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1.
The time delay experiment proposed by I.I. Shapiro in 1964 and conducted in the seventies was the most precise experiment
of general relativity until that time. Further experimentation has improved the accuracy level of both the time delay and
the light deflection experiments. A simulation model is proposed that involves only a simple mass and time transformation
factor involving velocity of light. The light deflection and the time delay experiments are numerically simulated using this
model that does not use the general relativistic equations. The computed values presented in this paper compare well with
recent levels of accuracy of their respective experimental results. 相似文献
2.
We describe the design, synthesis and biological evaluation of conformationally-locked 5'-acyl sulfamoyl adenosine derivatives as new parasitic inhibitors against Trypanosoma and Leishmania. The conformationally-locked (3'-endo, North-type) nucleosides have been synthesized by covalently attaching a 4'-CH(2)-O-2' bridge () across C2'-C4' of adenosine in order to reduce the conformational flexibility of the pentose ring. This is designed to decrease the entropic penalty for complex formation with the target protein, which may improve free-energy of stabilization of the complex leading to improved potency. Conformationally-locked 5'-acyl sulfamoyl adenosine derivatives (16-22) were tested against parasitic protozoans for the first time in this work, and showed potent inhibition of Trypanosoma cruzi, Trypanosoma brucei, Trypanosoma rhodesiense and Leishmania infantum with IC(50) = 0.25-0.51 μM. In particular, the potent 5'-pentanyl acyl sulfamoyl adenosine derivative 17 (IC(50) = 0.25 μM) against intracellular L. infantum amastigotes and Trypanosoma subspecies is interesting in view of its almost insignificant cytotoxicity in murine macrophage host cells (CC(50) >4 μM) and in diploid human fibroblasts MRC-5 cell lines (CC(50) 4 μM). This work also suggests that variable alkyl chain length of the acyl group on the acylsulfamoyl side chain at 5' can modulate the toxicity of 5'-O-sulfamoylnucleoside analogues. This conformationally-locked sulfamoyl adenosine scaffold presents some interesting possibilities for further drug design and lead optimization. 相似文献
3.
We present two new variants of Schur complement domain decompositionpreconditioners suitable for 2D anisotropic problems. Thesevariants are based on adaptations of the probing idea, describedby Chan et al (1992 Fifth Int. Symp. on Domain DecompositionMethods for Partial Differential Equations, Philadelphia: SIAM,pp 236-249), used in conjunction with a coarse grid approximationas introduced by Bramble et al (1986 Math. Comput. 47, 103-134).The new methods are specifically designed for situations wherethe coupling between neighbouring interfaces is stronger thanthe coupling within an interface. Taking into account this strongcoupling, one variant uses a multicolour probing technique toavoid distortion in the probe approximations that appear whenusing the method proposed by Chan et al. The second techniqueuses additional probe matrices to approximate not only the couplingwithin the interfaces but also the coupling between interfacepoints across the subdomains. This latter procedure looks somewhatlike an alternating line relaxation method for anisotropic problems,see Brandt (1977 Math. Comput.. 31, 333-390). To assess therelevance of the new preconditioners, we compare their numericalbehaviour with well known robust preconditioners such as thebalanced Neumann-Neumann method proposed by Mandel (1993 Commun.Numer. Methods Eng.. 9, 233-241). 相似文献
4.
The ‘anomalous perihelion precession’ of Mercury, announced by Le Verrier in 1859, was a highly controversial topic for more
than half a century and invoked many alternative theories until 1916, when Einstein presented his theory of general relativity
as an alternative theory of gravitation and showed perihelion precession to be one of its potential manifestations. As perihelion
precession was a directly derived result of the full General Theory and not just the Equivalence Principle, Einstein viewed
it as the most critical test of his theory. This paper presents the computed value of the anomalous perihelion precession
of Mercury's orbit using a new relativistic simulation model that employs a simple transformation factor for mass and time,
proposed in an earlier paper. This computed value compares well with the prediction of general relativity and is, also, in
complete agreement with the observed value within its range of uncertainty. No general relativistic equations have been used
for computing the results presented in this paper. 相似文献
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6.
Satheeshmanikandan RS Thappali Kanthikiran VS Varanasi Sridhar Veeraraghavan Swaroop Kumar VS Vakkalanka Mukkanti K 《Journal of mass spectrometry : JMS》2012,47(12):1612-1619
A sensitive and reliable high‐performance liquid chromatography–mass spectrometry (LC–MS/MS) was developed and validated for simultaneous quantification IC87114, roflumilast (RFM), and its active metabolite roflumilast N‐oxide (RFN) using tolbutamide as an internal standard. The analytes were extracted by using liquid–liquid extraction and separated on a reverse phase C18 column (50 mm × 3 mm i.d., 4.6 µ) using methanol: 2 mM ammonium acetate buffer, pH 4.0 as mobile phase at a flow rate 1 mL/min in gradient mode. Selective reaction monitoring was performed using the transitions m/z 398.3 > 145.9, 403.1 >186.9, 419.1 > 187.0 and 271.1 > 155.0 to quantify quantification IC87114, RFM, RFN and tolbutamide, respectively. The method was validated over the concentration range of 0.1–60 ng.mL?1 for RFM and RFN and 6 to 2980 ng.mL?1 for IC87114. Intra‐ and inter‐day accuracy and precision of validated method were within the acceptable limits of <15% at all concentrations. Coefficients of correlation (r2) for the calibration curves were >0.99 for all analytes. The quantitation method was successfully applied for simultaneous estimation of IC87114, RFM and RFN in a pharmacokinetic drug–drug interaction study in Wistar rats. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
7.
Munshi G Mustafa Sudhir Raniwala T Awes B Rai RS Bhalerao JG Contreras RV Gavai SK Ghosh P Jaikumar GC Mishra AP Mishra H Mishra B Mohanty J Nayak J-Y Ollitrault SC Phatak L Ramello R Ray PK Sahu AM Srivastava DK Srivastava VK Tiwari 《Pramana》2006,67(5):961-981
This is the report of Heavy Ion Physics and Quark-Gluon Plasma at WHEPP-09 which was part of Working Group-4. Discussion and
work on some aspects of quark-gluon plasma believed to have created in heavy-ion collisions and in early Universe are reported. 相似文献
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9.
MVN Murthy Urjit A Yajnik KRS Balaji G Bhattacharyya Amol Dighe Shashikant Dugad ND Hari Dass PK Kabir Kamales Kar D Indumathi John G Learned Debasish Majumdar NK Mondal MVN Murthy SN Nayak Sandip Pakvasa Amitava Raychaudhuri RS Raghavan G Rajasekaran R Ramachandran Alak K Ray Asim K Ray Saurabh Rindani HS Sharatchandra Rahul Sinha Nita Sinha S Umasankar Urjit A Yajnik 《Pramana》2000,55(1-2):347-355
We have identified some important and worthwhile physics opportunities with a possible neutrino detector located in India.
Particular emphasis is placed on the geographical advantage with a stress on the complimentary aspects with respect to other
neutrino detectors already in operation. 相似文献
10.
Upadhayaya RS Shinde PD Sayyed AY Kadam SA Bawane AN Poddar A Plashkevych O Földesi A Chattopadhyaya J 《Organic & biomolecular chemistry》2010,8(24):5661-5673
Prompted by our discovery of a new class of conformationally-locked indeno[2,1-c]quinolines as anti-mycobacterials, compounds 2a and 3a (Fig. 1; MIC < 0.39 μg mL(-1) and 0.78 μg mL(-1), respectively)(14) with a freely rotating C2-imidazolo substituent, we herein describe the synthesis of pentacyclic azole-fused quinoline derivatives 4 and 5, in which we have restricted the rotation of the C2-imidazolo moiety by fusing it to the adjacent quinoline-nitrogen to give a five-membered fused azole heterocycle. The idea of locking the flexibility of the system by conformational constraint was simply to reduce its entropy, thereby reducing the overall free-energy of its binding to the target receptor. Out of 22 different azole-fused indeno[2,1-c]quinoline derivatives, seven structurally distinct compounds, 9, 15, 17, 25, 27, 28 and 29, have shown 79-99% growth inhibition of Mycobacterium tuberculosis H37Rv at a fixed dose of 6.25 μg mL(-1). The efficacies of these compounds were evaluated in vitro for 8/9 consecutive days using the BACTEC radiometric assay upon administration of single dose on day one. Of these, two compounds, 9 and 28, inhibited growth of M. tuberculosis very effectively at MIC < 0.39 μg mL(-1) (0.89 μM and 1 μM, respectively). These active compounds 9, 15, 17, 25, 27, 28 and 29 were screened for their cytotoxic effect on mammalian cells (human monocytic cell line U937), which showed that the human cell survival is almost unperturbed (100% survival), except for compound 25, hence these new compounds with new scaffolds have been identified as potent anti-mycobacterials, virtually with no toxicity. Thus these "hit" molecules constitute our important "leads" for further optimization by structure-activity relationship against TB. 相似文献