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61.
Guipeng Cai Aravind Dasari Zhong-Zhen Yu Shaocong Dai Jiyang Wang 《Polymer Degradation and Stability》2010,95(5):845-45
To improve the fire retardancy performance of polyamide 6 (PA 6), layered silicates are used in combination with multi-walled carbon nanotubes (CNTs) to address the issue of packing density and uniformity of the protective inorganic barrier formed at the burning surface of the nanocomposites during combustion. Benzimidazolium is used to modify the silicate layers instead of conventional alkyl ammonium surfactants to tackle the issue of thermal stability. However, the poor dispersion of the modified layered silicates in PA 6 has a significant negative effect on the fire performance of the materials and offsets the positive effect of CNTs. Also, the results point to the apparent contradictions with different fire exposure tests; that is, significant reductions in heat release and mass loss rates in the cone calorimetry test do not imply a higher rating in the UL 94 vertical burning test. 相似文献
62.
We present a high-speed synthetic aperture microscopy for quantitative phase imaging of live biological cells. We measure 361 complex amplitude images of an object with various directions of illumination covering an NA of 0.8 in less than one-thirteenth of a second and then combine the images with a phase-referencing method to create a synthesized phase image. Because of the increased depth selectivity, artifacts from diffraction that are typically present in coherent imaging are significantly suppressed, and lateral resolution of phase imaging is improved. We use the instrument to demonstrate high-quality phase imaging of live cells, both static and dynamic, and thickness measurements of a nanoscale cholesterol helical ribbon. 相似文献
63.
Raghu Dasari Srinivas Gali Rajashekar Korra Namratha Vaddiraju 《Journal of heterocyclic chemistry》2024,61(4):642-650
A series of novel oxadiazole functionalized pyridopyrimidine derivatives prepared starting from 6-methyl/ethyl-2-oxo-4-(trifluoromethyl)-1,2-dihydropyridine-3-carbonitrile 1 . This compound 1 on reaction with sulfuric acid obtained compound 2 , further compound 2 on reaction with chloroacetamide followed by reaction with ethoxy methylene malonic diethyl ester coupling and further cyclization to obtain compound 5 . Compound 5 on reaction with hydrazide hydrate obtained hydrazide derivatives 6 . Compound 6 on reaction with diverse substituted aromatic acids to get oxadiazole derivatives 7a–l . All the final compounds 7a–l evaluated for anticancer activity against four human cancer cell lines such as HeLa—cervical cancer (CCL-2); COLO 205—colon cancer (CCL-222); HepG2—liver cancer (HB-8065); and MCF7—breast cancer (HTB-22) and promising compounds 7d and 7k have been identified and evaluated for molecular docking interactions. 相似文献
64.
Srinivasa Rao Dasari Subbaiah Tondepu Lakshmana Rao Vadali Mutyala Naidu Ganivada Nareshvarma Seelam 《Journal of heterocyclic chemistry》2019,56(1):195-208
In this research article, a highly efficient, cost‐effective synthesis of various hybrid molecules possessing 1,2,3‐triazolyltetrazoles and evaluation of their biological activity have been addressed. The structure elucidation of these new library hybrid molecules has been carried out by IR, 1H NMR, 13C NMR, and mass spectral analysis. The compounds have been screened for their anticancer activity against human colon cancer cell line Colo‐205 and human lung cancer cell line HOP‐205, and the results attest that most of the compounds have shown very good therapeutic nature. In particular, compounds 3d , 3j , 6a , and 6e were more cytotoxic than Adriamycin against all tested human cancer cell lines with 68%, 101.8%, 94%, and 104.5% growth, respectively. In the present investigation, a series of 3a – j and 6a – h were subjected to molecular properties prediction, drug likeness by Molinspiration, and toxicity risks by Molsoft software programs. All the 18 analogues were chosen on the basis of Lipinski “Rule of five” for the synthesis, screening their antibacterial and anticancer as oral bioavailable drugs/leads. 相似文献
65.
We have developed diffraction phase microscopy as a new technique for quantitative phase imaging of biological structures. The method combines the principles of common path interferometry and single-shot phase imaging and is characterized by subnanometer path-length stability and millisecond-scale acquisition time. The potential of the technique for quantifying nanoscale motions in live cells is demonstrated by experiments on red blood cells. 相似文献
66.
Popescu G Ikeda T Goda K Best-Popescu CA Laposata M Manley S Dasari RR Badizadegan K Feld MS 《Physical review letters》2006,97(21):218101
Using a novel noncontact technique based on optical interferometry, we quantify the nanoscale thermal fluctuations of red blood cells (RBCs) and giant unilamellar vesicles (GUVs). The measurements reveal a nonvanishing tension coefficient for RBCs, which increases as cells transition from a discocytic shape to a spherical shape. The tension coefficient measured for GUVs is, however, a factor of 4-24 smaller. By contrast, the bending moduli for cells and vesicles have similar values. This is consistent with the cytoskeleton confinement model, in which the cytoskeleton inhibits membrane fluctuations [Gov et al., Phys. Rev. Lett. 90, 228101, (2003). 相似文献
67.
Singh Surya P. Mukherjee Soumavo Galindo Luis H. So Peter T. C. Dasari Ramachandra Rao Khan Uzma Zubair Kannan Raghuraman Upendran Anandhi Kang Jeon Woong 《Analytical and bioanalytical chemistry》2019,411(6):1297-1297
Analytical and Bioanalytical Chemistry - The authors would like to bring to the reader’s attention that the Clarke error grid plot presented in Fig. 3 was generated using codes... 相似文献
68.
Extended depth of focus in tomographic phase microscopy using a propagation algorithm 总被引:1,自引:0,他引:1
Tomographic phase microscopy is a laser interferometry technique in which a 3D refractive index map of a biological sample is constructed from quantitative phase images collected at a set of illumination angles. Although the resulting tomographic images provide valuable information, their resolution declines at axial distances beyond about 1 microm from the focal plane. We describe an improved 3D reconstruction algorithm in which the field at the focal plane is numerically propagated to depths throughout the sample. Diffraction is thus incorporated, extending the depth of focus to more than 10 mum. Tomograms with improved focal depth are demonstrated for single HT29 cells. 相似文献
69.
Ramachandra R. Dasari Gregory M. Shimkaveg Michael S. Otteson Michael S. Feld 《Hyperfine Interactions》1987,38(1-4):711-722
The ability of optical pumping to produce nuclear orientation and the advent of single frequency tunable dye lasers has brought
about a new interesting area of study, Laser Induced Nuclear Orientation (LINO). The impact of LINO on the nuclear structure
studies of short lived nuclei along with a discussion on various relaxation mechanisms involved are presented. As an example,
recent experimental results on85mRb (T1/2=1.0 μs) are given in detail. Possible application of LINO to151Eu discussed. 相似文献
70.
We report on phase-dispersion optical tomography, a new imaging technique based on phase measurements using low-coherence interferometry. The technique simultaneously probes the target with fundamental and second-harmonic light and interferometrically measures the relative phase shift of the backscattered light fields. This phase change can arise either from reflection at an interface within a sample or from bulk refraction. We show that this highly sensitive (~5 degrees ) phase technique can complement optical coherence tomography, which measures electric field amplitude, by revealing otherwise undetectable dispersive variations in the sample. 相似文献