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- Basavoju, Srinivas, et al.
(författare)
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Pharmaceutical Co-crystallization of Norfloxacin
- 2006
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Ingår i: 2006 AAPS Annual Meeting and Exposition. - : American Association of Pharmaceutical Scientists.
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Konferensbidrag (refereegranskat)abstract
- Description: Aim: The objective of the study was to prepare co-crystal and salts of norfloxacin and to investigate their structural and pharmaceutical properties. Methods: Norfloxacin was crystallized in a series of solvents in an effort to investigate the polymorphism. Norfloxacin was also co-crystallized with isonicotinamide and succinic acid in different solvents. We have characterised these materials using DSC, IR, Raman and PXRD. The single crystal X-ray diffraction data was obtained and crystal structures were solved. The solubility and moisture sorption behaviour (0-90%RH) of these materials were determined. Results: Norfloxacin Anhydrate, 1 crystallizes in the triclinic P-1 space group with one neutral molecule in the asymmetric unit. The carboxylic acid group participates in the intramolecular O-HO (D=2.525 Å) hydrogen bonding with carbonyl group of the quinolone moiety. NorfloxacinIsonicotinamideCHCl3, 2 crystallizes in the centrosymmetric C2/c space group with one molecule of norfloxacin, one molecule of isonicotinamide and one molecule of CHCl3.in the asymmetric unit. Four molecules of norfloxacin generate a rectangular host type network with N-HO (D=2.668 Å) and N-HO (D=2.657 Å) interactions. Two isonicotinamide molecules form robust amideamide (N-HO, D=2.889 Å) homodimer synthon and fits into the rectangular grid (N-HO, D=2.929 Å). The CHCl3 molecules lie in the channels of the host frame work. Norfloxacin (Succinate)0.5 Hydrate, 3 crystallizes in the triclinic P-1 space group with one norfloxacin cation, half molecule of succinate dianion and one H2O molecule in the asymmetric unit. The two succinate anions and two norfloxacin cations form a cyclic tetramer synthon (N-HO, D=2.726 Å) and extends with H2O molecules through the hydrophilic channel generated by quinolone stacked layers (ππ, 4.041 Å) along the a-axis via O-HO (D=2.928 Å) interactions. The rank order of the solubility of these materials was 1<2
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| 2. |
- Hameed, Khurram, et al.
(författare)
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Far-Field DOA Estimation of Uncorrelated RADAR Signals through Coprime Arrays in Low SNR Regime by Implementing Cuckoo Search Algorithm
- 2022
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Ingår i: Electronics. - : MDPI AG. - 2079-9292. ; 11:4
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Tidskriftsartikel (refereegranskat)abstract
- For the purpose of attaining a high degree of freedom (DOF) for the direction of arrival (DOA) estimations in radar technology, coprime sensor arrays (CSAs) are evaluated in this paper. In addition, the global and local minima of extremely non-linear functions are investigated, aiming to improve DOF. The optimization features of the cuckoo search (CS) algorithm are utilized for DOA estimation of far-field sources in a low signal-to-noise ratio (SNR) environment. The analytical approach of the proposed CSAs, CS and global and local minima in terms of cumulative distribution function (CDF), fitness function and SNR for DOA accuracy are presented. The parameters like root mean square error (RMSE) for frequency distribution, RMSE variability analysis, estimation accuracy, RMSE for CDF, robustness against snapshots and noise and RMSE for Monte Carlo simulation runs are explored for proposed model performance estimation. In conclusion, the proposed DOA estimation in radar technology through CS and CSA achievements are contrasted with existing tools such as particle swarm optimization (PSO).
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| 3. |
- Khan, Wasim, et al.
(författare)
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A Multi-Cohort Study of ApoE epsilon 4 and Amyloid-beta Effects on the Hippocampus in Alzheimer's Disease
- 2017
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Ingår i: Journal of Alzheimer's Disease. - 1387-2877 .- 1875-8908. ; 56:3, s. 1159-1174
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Tidskriftsartikel (refereegranskat)abstract
- The apolipoprotein E (APOE) gene has been consistently shown to modulate the risk of Alzheimer's disease (AD). Here, using an AD and normal aging dataset primarily consisting of three AD multi-center studies (n = 1,781), we compared the effect of APOE and amyloid-beta (A beta) on baseline hippocampal volumes in AD patients, mild cognitive impairment (MCI) subjects, and healthy controls. A large sample of healthy adolescents (n = 1,387) was also used to compare hippocampal volumes between APOE groups. Subjects had undergone a magnetic resonance imaging (MRI) scan and APOE genotyping. Hippocampal volumes were processed using FreeSurfer. In the AD and normal aging dataset, hippocampal comparisons were performed in each APOE group and in epsilon 4 carriers with positron emission tomography (PET) A beta who were dichotomized (A beta+/A beta-) using previous cut-offs. We found a linear reduction in hippocampal volumes with epsilon 4 carriers possessing the smallest volumes, epsilon 3 carriers possessing intermediate volumes, and epsilon 2 carriers possessing the largest volumes. Moreover, AD and MCI epsilon 4 carriers possessed the smallest hippocampal volumes and control epsilon 2 carriers possessed the largest hippocampal volumes. Subjects with both APOE epsilon 4 and A beta positivity had the lowest hippocampal volumes when compared to A beta-epsilon 4 carriers, suggesting a synergistic relationship between APOE epsilon 4 and A beta. However, we found no hippocampal volume differences between APOE groups in healthy 14-year-old adolescents. Our findings suggest that the strongest neuroanatomic effect of APOE epsilon 4 on the hippocampus is observed in AD and groups most at risk of developing the disease, whereas hippocampi of old and young healthy individuals remain unaffected.
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