215 research outputs found
Transition-metal-free, atom-economical cascade synthesis of novel 2-sulfonated-benzo[f][1,7]naphthyridines and their cytotoxic activities
No full textAn efficient, transition-metal-free cascade synthetic method has been developed for new 2-aryl/heteroaryl sulfonated benzo[f][1,7]naphthyridines. It is tert-butyl hydroperoxide (TBHP) mediated highly regioselective sulfonylation？cyclization？aromatization process between N-(3-aryl/heteroarylprop-2-yn-1-yl)quinolin-3-amines and aryl/heteroaryl sulfonylhydrazides. This synthetic protocol offers one-step strategy for C？S and C？C bond formations with a broad range of functional group tolerance. It is a simple, mild, and atom-economical route for the synthesis of various valuable functionalized 1, 2-aryl/heteroaryl sulfonated benzo[f][1,7]naphthyridines in moderate yields. Since the core motif of 2-sulfonated benzo[f][1,7]naphthyridines are biologically and pharmaceutically important (TLR activity 7, 8 modulators). Additionally, the synthesized derivatives were evaluated for their in vitro cytotoxic activities against six human cancer cell lines including lung (NCIH23), colon (HCT15), gastric (NUCG-3), renal (ACHN), prostate (PC-3), and breast (MDA-MB-231) cell lines. These compounds displayed significant cytotoxic activities against all tested human cancer cell lines
Design, synthesis and biological evaluation of 1,3-diphenylbenzo[f][1,7]naphthyrdines
No full textA novel series of twenty 1,3-diphenylbenzo[f][1,7]benzonaphthyrdine derivatives were designed and synthesized through intermolecular imino Diels-Alder reaction. Their in vitro cytotoxic activities were evaluated against six human cancer cell lines (NCIH23, HCT15, NUGC-3, ACHN, PC-3, and MDA-MB-231). Majority of synthesized compounds exhibited significant cytotoxic activities against all tested human cancer cell lines. Among them 4l, 4m, and 4o derivatives exhibited most promising cytotoxic activities. Furthermore these compounds were evaluated against human Topoisomerase IIα inhibition. Interestingly, the compound 4l exhibited 1.3 and 1.2 times more potent human Topoisomerase IIα inhibition than the reference drug etoposide in both 100 μM and 20 μM concentrations respectively. Molecular docking studies for the compound 4l have also been executed by Sybyl X-2.1 in which it reveals the binding site of the compound 4l with topo IIα DNA cleavage site where etoposide was situated. The benzo[f][1,7]naphthyridine ring was stacked between the DNA bases of the cleavage site
A two-stage genome-wide association study of sporadic amyotrophic lateral sclerosis
No full textThe cause of sporadic amyotrophic lateral sclerosis (ALS) is largely unknown, but genetic factors are thought to play a significant role in determining susceptibility to motor neuron degeneration. To identify genetic variants altering risk of ALS, we undertook a two-stage genome-wide association study (GWAS): we followed our initial GWAS of 545 066 SNPs in 553 individuals with ALS and 2338 controls by testing the 7600 most associated SNPs from the first stage in three independent cohorts consisting of 2160 cases and 3008 controls. None of the SNPs selected for replication exceeded the Bonferroni threshold for significance. The two most significantly associated SNPs, rs2708909 and rs2708851 [odds ratio (OR) = 1.17 and 1.18, and P-values = 6.98 x 10–7 and 1.16 x 10–6], were located on chromosome 7p13.3 within a 175 kb linkage disequilibrium block containing the SUNC1, HUS1 and C7orf57 genes. These associations did not achieve genome-wide significance in the original cohort and failed to replicate in an additional independent cohort of 989 US cases and 327 controls (OR = 1.18 and 1.19, P-values = 0.08 and 0.06, respectively). Thus, we chose to cautiously interpret our data as hypothesis-generating requiring additional confirmation, especially as all previously reported loci for ALS have failed to replicate successfully. Indeed, the three loci (FGGY, ITPR2 and DPP6) identified in previous GWAS of sporadic ALS were not significantly associated with disease in our study. Our findings suggest that ALS is more genetically and clinically heterogeneous than previously recognized. Genotype data from our study have been made available online to facilitate such future endeavors
Preparation and mass-spectrometric analysis of some partially methylated alditol acetates from d-galactose
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Tensile loading of ropes of single wall carbon nanotubes and their mechanical properties
No full textThe mechanical response of 15 single wall carbon nanotube (SWCNT) ropes under tensile load was measured. For 8 of these ropes strain data were obtained and they broke at strain values of 5.3% or lower. The force-strain data are well fit by a model that assumes the load is carried by the SWCNTs on the perimeter of each rope. This model provides an average breaking strength of SWCNTs on the perimeter of each rope; the 15 values range from 13 to 52 GPa (mean 30 GPa). Based on the same model the 8 average Young's modulus values determined range from 320 to 1470 GPa (mean 1002 GPa)
Sporadic Burkitt Lymphoma with Orbital Extramedullary Infiltration
No full text<b><i>Background/Aims:</i></b> Sporadic Burkitt lymphoma is rarely associated with orbital involvement. <b><i>Methods:</i></b> We present a case of sporadic Burkitt lymphoma with extramedullary subperiosteal leukemic infiltrates of the orbit and facial bones. <b><i>Results:</i></b> Follow-up examination after chemotherapy and disease remission reveals resolution of the subperiosteal infiltrates. <b><i>Conclusion:</i></b> Despite an aggressive presentation, cure is common with appropriate, intensive treatment. To our knowledge, this report is the first to photographically depict the resolution of extramedullary orbital subperiosteal leukemic infiltrates after appropriate chemotherapy.</jats:p
Transmission-electron-microscopic studies of mechanical properties of single-walled carbon nanotube bundles
No full textThe mechanical properties of single-walled carbon nanotube bundles were studied via the observation of mechanical resonance in a transmission electron microscope. The bundles were capacitively actuated using tunable ac signals applied through a custom built specimen holder. Resonant frequencies ranging from 0.2 to 9 MHz were observed in bundles of diameters and lengths ranging from 15 to 70 nm, and from 1 to 10 \ub5m, respectively. An effective bending modulus of Eb = 76\ub14 GPa was extracted from the data. Onset of nonlinear frequency response was observed under large actuation amplitudes.NRC publication: Ye
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