12 research outputs found
Microwave assisted reaction, photophysical studies and antibacterial activities of simple sugar chalcone derivatives
No full text121-125Aldol condensation is adopted for the synthesis of sugar chalcone derivatives from β-C-glycosidic ketones with various
aromatic aldehydes under basic conditions with both conventional heating as well as microwave irradiation. Microwave
assisted reaction gives excellent yields. Products obtained have been characterized using 1H and 13C NMR and elemental
analysis. Sugar chalcone derivatives exhibit excellent antibacterial activity
Introduction of an α,β-unsaturated carbonyl conjugated pyrene–lactose hybrid as a fluorescent molecular probe for micro-scale anisotropic media
No full textA new fluorescent lactose molecule (pyd-lact) (E)-1-(galactose-β-(1→4)-β-D-glucopyranosyl)-4-(1-pyrene)-but-3-en-2-one, has been synthesized by attaching 1-pyrene-but-3-ene-2-one to lactose. Extended π-conjugation removes the emission forbiddenness of pyrene, which results in the broad spectrum. Detailed photo-physical studies in homogeneous media show the sensitivity of ICT (intra molecular charge transfer) emission towards medium polarity. Unlike pyrene, pyd-lact is more soluble in water at a probe concentration of 10 μM, because of the attached disaccharide. Thus, the usage of pyd-lact as an aqueous probe is found to be advantageous over pyrene. Using the polarity sensitivity of fluorescence parameters (intensity, shift of emission maximum, anisotropy, lifetime), the micro-heterogeneity of anisotropic media such as β-CD, bile salts, and Pluronic P123 have been monitored. In contrast to pyrene-3-carboxaldehyde, which is often used as a hydrophobic fluorescent molecular probe, pyd-lact reports from the interfacial regions of micro-heterogeneous media
Design, synthesis and metal sensing studies of ether-linked bis-triazole derivatives
No full textEther-linked-bis-triazole derivatives have been synthesized by (CuAAC) "Click" reaction and well characterized by NMR spectroscopy, mass spectrometry, and elemental analysis. Application of these materials in the field of sensors has also been demonstrated using various spectroscopic techniques. The interaction of the compound with Hg2+ was further confirmed by computational studies
Microwave assisted reaction, photophysical studies and antibacterial activities of simple sugar chalcone derivatives
Get PDFAldol condensation is adopted for the synthesis of sugar chalcone derivatives from b-C-glycosidic ketones with various aromatic aldehydes under basic condition with both conventional as well as microwave condition. Microwave assisted reaction gave an excellent yield. Products obtained were characterized using (1H, 13C) and elemental analysis. Sugar chalcone derivatives exhibited an excellent antibacterial activity.
A Lagrangian passive scalar solver for mass transport in electrolytes and coupling to the particle-resolved Bluebottle: code development, testing & validation
No full textWater electrolysis is a popular energy storage technique used in tandem with many renewable sources to convert the generated energy into storeable hydrogen. The efficiency of water electrolyzers is greatly affected by overpotential losses. Bubble evolution is a unique characteristic of flows in water electrolysis. The evolution of bubbles alter electrokinetics close to the electrodes and vary ionic mass transport. The localized flow features close to a bubble are often attributed to the variation in the current density and subsequently, the electrolyzer efficiency. For the purpose of modelling flows close to a bubble better, a Lagrangian method for the simulation of passive tracers is developed and programmed to be coupled to the flow field of Bluebottle, an open-source particulate multiphase flow solver that uses the Physalis algorithm.The dynamics of the tracers are modelled using a simplified Langevin equation. In the present work, the migration flux is omitted and priority is given to convection and diffusion with the objective of establishing a foundation for the simulation of ionic mass transport. Brownian motion is described using a random displacement term. The coupling with the flow field is achieved using trilinear interpolation. The domain boundaries in regards to tracer dynamics are modelled as either a rigid wall pair or as a periodic boundary pair. Specular reflection is programmed for the former ensuring elastic collision of a tracer with the domain boundary. For the latter, the tracer position is altered so as to place the tracer in the opposite side of the domain in the axis of intrusion. Particles are assumed to be non-penetrative and hence, specular reflection is implemented at the surface of each particle. Since the tracer module is coupled one-way with the flow field and executed after a Bluebottle time-step, a subroutine is developed to push the tracers out of a particle radially if a tracer is located inside a particle after a Bluebottle time-step. To ensure particle interaction is ensured across periodic boundaries, a subroutine is developed that places the particle in an apparent location that enables particle-tracer interaction. The module execution time is found to be linearly proportional to the number of particles and the number of tracers and consumes roughly 10% of a Bluebottle iteration execution time in nominal tests. The module is tested to ensure the Brownian displacement term obeys diffusion statistics and also to ensure that the trilinear interpolation works as intended. The numerically enforced no-penetration boundary at particle surfaces is also tested and observed to prevent intrusion of tracers. The tracer module is then used to stochastically simulate mass transport across a particulate suspension in a stagnant and a sheared flow field. The Sherwood number Sh determined from the tracer module is found to agree well with the expected experimental and numerical results of Wang et al. (2009). The tracer module is also compared to a scalar field solver of Bluebottle. The tracer module is observed to capture features of the flow field quite well. However, the transient tracer positions upon conversion to a transient continuous concentration field exhibits noise due to the discrete nature of the tracers. Hence, transient comparisons with a continuous field in terms of absolute magnitude requires a large number of tracers.Recommendations for improvement of the code is provided. The present work is intended to be followed up with the addition of migration flux to the equations of motion for the tracers through the solution of an additional equation for velocity of the tracer using a force equivalence of Coulomb's law and Stokes' drag law. Future challenges that will be encountered in the development of an accurate ionic mass transport solver is briefly discussed
An easy access to novel sugar-based spirooxindole-pyrrolidines or -pyrrolizidines through [3+2] cycloaddition of azomethine ylides
No full textAn efficient one-pot synthesis of a library of novel sugar-based spirooxindole-pyrrolidines or -pyrrolizidines has been accomplished by [3+2] cycloaddition. This method utilizes an azomethine ylide derived from isatin and sarcosine or l-proline with an α,β-unsaturated β-C-glycosidic ketone as the dipolarophile. All these sugar-based heterocyclics were characterized by NMR (1H and 13C), HPLC, and elemental analysi
Evaluating Central Aortic Blood Pressures in a Tertiary South Indian Hospital
No full textAbstract
Background Of late, central aortic blood pressure (CABP) has emerged as a better parameter than peripheral blood pressure (BP) in the diagnosis of cardiovascular events. Advent of new technologies has facilitated the calculation of CABP from machine-derived peripheral BP. In this study, the author determined the differences between peripheral BP measured manually or by machine and machine-derived CABP and examined whether this difference is stable even after categorizing the sample pool based on sex, hypertension, diabetes status, and β-blocker use.
Materials and Methods A total of 83 patients (both male and female) who attended the cardiology outpatient department were enrolled in the study. BP was recorded both manually and using Mobil-O-Graph pulse wave analyzer (ARC Solver) in the patient's sitting posture. The author compared the derived central, manual, and device-measured BP among the patient samples and assessed whether sex, hypertension, diabetes, and β-blocker use influence these differences.
Results Among the study population, 28 were females and 55 were males; patients’ mean age was 59.97 ± 12.15 years. The mean peripheral systolic BP (SBP) and diastolic BP (DBP) measured manually were127.55 ± 20.15 and 79.73 ± 9.57 mm Hg, respectively. Similar measurements recorded by the device were 129.68 ± 19.93 and 78.92 ± 13.48, respectively. The derived mean central aortic SBP and DBP was 117.69 ± 17.78 and 80.15 ± 13.71, respectively. Statistically significant difference in the manual and central aortic SBP (9.85 ± 11.16; p < 0.0001) was observed. This difference was significant irrespective of sex, hypertension, diabetes status, and β-blocker use. Similarly, difference between machine-derived peripheral SBP and central aortic SBP was statistically significant (p < 0.0001). However, the difference in manual and central aortic DBP was nonsignificant (p = 0.6976). Interestingly, a small (−1.34 ± 2.28) but statistically significant difference (p < 0.0001) between machine-derived peripheral DBP and central aortic DBP was observed. Further analysis to find out effect of β-blocker use on CABP revealed that the central aortic SBP is slightly, but statistically significantly, lower in β-blocker users (117.7 ± 17.71; p < 0.0001) than that of β-blocker nonusers (118.9 ± 18.37; p< 0.0001).
Conclusion Central aortic systolic pressure is statistically significantly lower than the manually recorded peripheral SBP irrespective of sex, hypertension, diabetes status, and β-blocker use. A small but significant difference was observed between machine-derived peripheral DBP and central aortic DBP. Patients using β-blockers were observed to have marginally lower CABP values than those who are not using them.</jats:p
Design and synthesis of sugar-triazole based uracil appended sugar-imine derivatives – an application in DNA binding studies
No full textSeveral sugar-triazole derivatives were synthesized and characterized by spectroscopic techniques. The interaction of the sugar-triazoles with CT-DNA was explored, which revealed that all the compounds could interact with CT-DNA through groove binding, which was further supported by a docking analysis
