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61.
Higher-order aberration correction in abnormal eyes can result in significant vision improvement, especially in eyes with abnormal corneas. Customized optics such as phase plates and customized contact lenses are one of the most practical, nonsurgical ways to correct these ocular higher-order aberrations. We demonstrate the feasibility of correcting higher-order aberrations and improving visual performance with customized soft contact lenses in keratoconic eyes while compensating for the static decentration and rotation of the lens. A reduction of higher-order aberrations by a factor of 3 on average was obtained in these eyes. The higher-order aberration correction resulted in an average improvement of 2.1 lines in visual acuity over the conventional correction of defocus and astigmatism alone. 相似文献
62.
Ramkumar Raghu Mahadesh Panju Vaneet Aggarwal Vinod Sharma 《Entropy (Basel, Switzerland)》2021,23(12)
Multicasting in wireless systems is a natural way to exploit the redundancy in user requests in a content centric network. Power control and optimal scheduling can significantly improve the wireless multicast network’s performance under fading. However, the model-based approaches for power control and scheduling studied earlier are not scalable to large state spaces or changing system dynamics. In this paper, we use deep reinforcement learning, where we use function approximation of the Q-function via a deep neural network to obtain a power control policy that matches the optimal policy for a small network. We show that power control policy can be learned for reasonably large systems via this approach. Further, we use multi-timescale stochastic optimization to maintain the average power constraint. We demonstrate that a slight modification of the learning algorithm allows tracking of time varying system statistics. Finally, we extend the multi-time scale approach to simultaneously learn the optimal queuing strategy along with power control. We demonstrate the scalability, tracking and cross-layer optimization capabilities of our algorithms via simulations. The proposed multi-time scale approach can be used in general large state-space dynamical systems with multiple objectives and constraints, and may be of independent interest. 相似文献
63.
Sowmya Chaganti Bhoopendra Singh Kushwah Laximan Velip Shristy S. Tiwari Shrilekha Chilvery Chandraiah Godugu Gananadhamu Samanthula 《Biomedical chromatography : BMC》2024,38(5):e5849
Nirmatrelvir (NRV), a 3C-like protease or Mpro inhibitor of SARS-CoV-2, is used for the treatment of COVID-19 in adult and paediatric patients. The present study was accomplished to investigate the comprehensive metabolic fate of NRV using in vitro and in vivo models. The in vitro models used for the study were microsomes (human liver microsomes, rat liver microsomes, mouse liver microsomes) and S9 fractions (human liver S9 fractions and rat liver S9 fractions) with the appropriate cofactors, whereas Sprague–Dawley rats were used as the in vivo models. Nirmatrelvir was administered orally to Sprague–Dawley rats, which was followed by the collection of urine, faeces and blood at pre-determined time intervals. Protein precipitation was used as the sample preparation method for all the samples. The samples were then analysed by liquid chromatography–quadrupole time-of-flight tandem mass spectrometry (LC-Q-ToF-MS/MS) using an Acquity BEH C18 column with 0.1% formic acid and acetonitrile as the mobile phase. Four metabolites were found to be novel, which were formed via amide hydrolysis, oxidation and hydroxylation. Furthermore, an in silico analysis was performed using Meteor Nexus software to predict the probable metabolic changes of NRV. The toxicity and mutagenicity of NRV and its metabolites were also determined using DEREK Nexus and SARAH Nexus. 相似文献
64.
Selvakumar M. Ramkumar T. Chandrasekar P. 《Journal of Thermal Analysis and Calorimetry》2019,135(1):419-436
Journal of Thermal Analysis and Calorimetry - Numerical simulation of mixed convection heat transfer in a lid-driven triangular cavity filled with power law nanofluid and with an opening was... 相似文献
65.
Narayanasamy P. Selvakumar M. Ramkumar T. Mohanraj M. Pillai G. Pitchayya 《Journal of Thermal Analysis and Calorimetry》2021,145(5):2335-2342
Journal of Thermal Analysis and Calorimetry - In this paper, the detailed characterization of mechanical, electrical and thermal properties of Ag nanoparticle-reinforced Al6061 alloy was studied.... 相似文献
66.
Vellaisamy K Napoleon JV Venkatachalam R Manheri MK 《Chemical communications (Cambridge, England)》2010,46(48):9212-9214
Reductive transformation of the dipeptide BocAlaAlaOMe to a complex, internally charge-stabilized, natural product-like skeleton in one synthetic step is discussed. Stepwise replacement of the B-H bonds in borane by B-N or B-O resulted in incorporation of three boron atoms in a tetracyclic framework whereby one is stereogenic! 相似文献
67.
S. Rajeswari G. Venkatesa Prabhu D. Tamilvendan V. Ramkumar 《Journal of chemical crystallography》2009,39(9):650-654
Abstract A new mannich base 1-[(2,5-dioxopyrrolidin-1-yl)(phenyl)methyl] thiourea formed by the direct condensation of thiourea, succinimide
and benzaldehyde has been synthesized. The structure of this mannich base has been elucidated on the basis of micro elemental
analysis, IR, 1H NMR, 13C NMR, Mass and UV–Visible Techniques. The crystal structure of the title compound C12 H13 N3 O2 S was determined. It crystallizes in the monoclinic system, space group P21/c with a = 10.8234 (7) ?, b = 6.0355 (5) ?, c = 19.3692 (14) ?, β = 100.540(3)°, Z = 4 and V = 1243.94 (16) ?3. The structure was solved by the full-matrix least squares on F
2 and had a refined R value of 0.0465 for 1,964 observed reflections. The crystal structure is stabilized by strong intramolecular C–H···O, C–H···S
interactions and inter molecular N–H···O and S···S interactions.
Graphical Abstract This paper describes the spectroscopic and crystallographic studies of the title compound which is essential in ascertaining
the structure of this new compound.
相似文献
68.
S. Rajeswari G. Venkatesa Prabhu D. Tamilvendan V. Ramkumar 《Journal of chemical crystallography》2010,40(5):437-442
Abstract
A new mannich base 1-(morpholino(phenyl)methyl)pyrrolidine-2,5-dione formed by the direct condensation of morpholine, succinimide and benzaldehyde has been synthesized. The structure of this mannich base has been elucidated on the basis of micro elemental analysis, IR, 1H NMR, 13C NMR, UV–Visible Techniques and Mass. The crystal structure of the title compound C15 H18 N2 O3 was determined. It crystallizes in the triclinic system, space group P − 1, with a = 8.8122(13) ?, b = 9.2794(14) ?, c = 9.814 (3) ?, α = 107.154(9)°, β = 97.936(9)°, γ = 110.197(7)°,V = 693.4(2) ?3, D x = 1.314 Mg/m3. The structure was solved by the full-matrix least squares on F2 and had a refined R value of 0.0486 for 8567 observed reflections. The six membered heterocyclic ring of the morpholino moiety adopts a chair conformation. The crystal structure is stabilized by weak intermolecular C–H···O interactions that link the molecules into inversion dimers. 相似文献69.
70.
Ramkumar Kothandam Muthuraman Pandurangan R. Jayavel Sanjeev Gupta 《Journal of Cluster Science》2016,27(4):1263-1272
The present study was aimed to investigate the novel approach for the promotion of leather finishing properties through the incorporation of copper nanoparticles (Cu nanoparticles). Cu nanoparticles were synthesized by chemical reduction method, and particle sizes were in the range of 25–50 nm. X-ray diffraction, transmission electron microscope, ultra violet-vis spectrometry and scanning electron microscopy were used to characterize the Cu nanoparticles. The ascorbic acid was used as a protective agent to prevent the oxidation. Polyvinylpyrrolidone used as a stabilizing and dispersing agent, whereas sodium borohydride was used as a reducing agent. Spray coatings were carried out with Cu nanoparticles on both base and top coat formulations to evaluate their performance properties. Interestingly, the Cu nanoparticles coated leather samples showed the improved wet and rub fastness, color fastness to water and adhesion strength. 相似文献