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991.
Sandra Piras Gabriele Murineddu Giovanni Loriga Antonio Carta Enrica Battistello Stefania Merighi Stefania Gessi Paola Corona Battistina Asproni Roberta Ibba Veronika Temml Daniela Schuster Grard Aim Pinna 《Molecules (Basel, Switzerland)》2021,26(18)
Opioid analgesics are clinically used to relieve severe pain in acute postoperative and cancer pain, and also in the long term in chronic pain. The analgesic action is mediated by μ-, δ-, and κ-receptors, but currently, with few exceptions for k-agonists, μ-agonists are the only ones used in therapy. Previously synthesized compounds with diazotricyclodecane cores (DTDs) have shown their effectiveness in binding opioid receptors. Fourteen novel diazatricyclodecanes belonging to the 9-propionyl-10-substituted-9,10-diazatricyclo[4.2.1.12,5]decane (compounds 20–23, 53, 57 and 59) and 2-propionyl-7-substituted-2,7-diazatricyclo[4.4.0.03,8]decane (compounds 24–27, 54, 58 and 60) series, respectively, have been synthesized and their ability to bind to the opioid μ-, δ- and κ-receptors was evaluated. Five of these derivatives, compounds 20, 21, 24, 26 and 53, showed μ-affinity in the nanomolar range with a negligible affinity towards δ- and κ-receptors and high μ-receptor selectivity. The synthesized compounds showed μ-receptor selectivity higher than those of previously reported methylarylcinnamyl analogs. 相似文献
992.
Photoluminescence and Photoacoustic Spectroscopies of Fe3+ in the LiGa5O8–LiGaSiO4–Li5GaSi2O8 System
This report is devoted to the study of the low and room temperature photoluminescence and photoacoustic spectroscopy of the
Fe3+ impurity ion in the LiGa5O8–LiGaSiO4–Li5GaSi2O8 system. The sample was obtained by solid-state reaction between β-Ga2O3, Li2CO3, SiO2 and appropriated quantities of Fe2O3. It was investigated by X-ray diffraction to determine the formed phases and through photoluminescence, excitation and photoacoustic
spectroscopy measurements. The broad absorption and emission bands in the visible and near-infrared spectral regions presented
by that system constitute the motivation for this study. More specifically, the luminescence occurs over a large interval
of wavelengths, between 400 nm and 800 nm. 相似文献
993.
Cara L Ryan David C Baranowski Babykumari P Chitramuthu Suneil Malik Zhi Li Mingju Cao Sandra Minotti Heather D Durham Denis G Kay Christopher A Shaw Hugh PJ Bennett Andrew Bateman 《BMC neuroscience》2009,10(1):1-22
Background
Progranulin is a secreted high molecular weight growth factor bearing seven and one half copies of the cysteine-rich granulin-epithelin motif. While inappropriate over-expression of the progranulin gene has been associated with many cancers, haploinsufficiency leads to atrophy of the frontotemporal lobes and development of a form of dementia (frontotemporal lobar degeneration with ubiquitin positive inclusions, FTLD-U) associated with the formation of ubiquitinated inclusions. Recent reports indicate that progranulin has neurotrophic effects, which, if confirmed would make progranulin the only neuroprotective growth factor that has been associated genetically with a neurological disease in humans. Preliminary studies indicated high progranulin gene expression in spinal cord motor neurons. However, it is uncertain what the role of Progranulin is in normal or diseased motor neuron function. We have investigated progranulin gene expression and subcellular localization in cultured mouse embryonic motor neurons and examined the effect of progranulin over-expression and knockdown in the NSC-34 immortalized motor neuron cell line upon proliferation and survival.Results
In situ hybridisation and immunohistochemical techniques revealed that the progranulin gene is highly expressed by motor neurons within the mouse spinal cord and in primary cultures of dissociated mouse embryonic spinal cord-dorsal root ganglia. Confocal microscopy coupled to immunocytochemistry together with the use of a progranulin-green fluorescent protein fusion construct revealed progranulin to be located within compartments of the secretory pathway including the Golgi apparatus. Stable transfection of the human progranulin gene into the NSC-34 motor neuron cell line stimulates the appearance of dendritic structures and provides sufficient trophic stimulus to survive serum deprivation for long periods (up to two months). This is mediated at least in part through an anti-apoptotic mechanism. Control cells, while expressing basal levels of progranulin do not survive in serum free conditions. Knockdown of progranulin expression using shRNA technology further reduced cell survival.Conclusion
Neurons are among the most long-lived cells in the body and are subject to low levels of toxic challenges throughout life. We have demonstrated that progranulin is abundantly expressed in motor neurons and is cytoprotective over prolonged periods when over-expressed in a neuronal cell line. This work highlights the importance of progranulin as neuroprotective growth factor and may represent a therapeutic target for neurodegenerative diseases including motor neuron disease. 相似文献994.
The present research sought to investigate the effect of noise, comparable to that experienced in an aircraft cabin, on cognitive performance in terms of working memory and recognition memory. In addition, and since advancements in technology have long permitted the exchange of information via various media, the present research also sought to investigate the effect of in-cabin aircraft noise on the medium in which the target signal is delivered. Thirty-two participants (19 female), half non-native English speakers with an average age of 21.84 years (SD = 3.16), and all with normal hearing were asked to complete four different memory tasks under two different experimental factors. The first independent variable was noise, with two conditions: no noise versus wideband noise at 80 dBA. The second independent variable was mode of presentation, with two conditions: target signal presented aurally or visually. With the presentation of stimuli presented in a counterbalanced order, the results from a series of mixed repeated measures analyses revealed that working memory appears largely immune from the effects of wideband noise at 80 dBA. In contrast, recognition memory is most vulnerable to the effects of this noise. In terms of mode of delivery, presenting the target signal visually improves recall performance on the recognition memory task and two of the three working memory tasks (not the linguistics working memory task). Also noise had a greater effect on non-native English speakers on the recognition memory task. These results highlight the varying effect of noise on memory, and the benefits of considering alternate methods of presenting information in noisy settings, such as aviation. 相似文献
995.
Hydration of gas-phase ions formed by electrospray ionization 总被引:1,自引:0,他引:1
Sandra E. Rodriguez-Cruz John S. Klassen Evan R. Williams 《Journal of the American Society for Mass Spectrometry》1999,10(10):958-968
The hydration of gas-phase ions produced by electrospray ionization was investigated. Evidence that the hydrated ions are formed by two mechanisms is presented. First, solvent condensation during the expansion inside the electrospray source clearly occurs. Second, some solvent evaporation from more extensively solvated ions or droplets is apparent. To the extent that these highly solvated ions have solution-phase structures, then the final isolated gas-phase structure of the ion will be determined by the solvent evaporation process. This process was investigated for hydrated gramicidin S in a Fourier-transform mass spectrometer. Unimolecular dissociation rate constants of isolated gramicidin S ions with between 2 and 14 associated water molecules were measured. These rate constants increased from 16 to 230 s-1 with increasing hydration, with smaller values corresponding to magic numbers. 相似文献
996.
Cancellous bone is a two–component structure consisting of the bone frame and interstitial blood marrow. In the scope of this presentation, the multiscale finite element method is used for its modeling. This method results from a combination of homogenization theory and the theory of finite elements and is based on the calculation of effective material parameters by investigating representative volume elements (RVEs). For the particular kind of material considered here, a cubic two–phase RVE is assumed where the dry skeleton is modeled in different ways. Apart from the variations of the geometry, the influence of the usage of different types of finite elements is studied in this context. Note that the presence of a liquid phase requires dynamic investigation including the viscous phenomena. To this end, acoustic excitation and an analysis in the complex domain are chosen. The method permits calculation of the effective material parameters such as Young's modulus, bulk modulus and Poisson's ratio and furthermore the simulation of the behaviour of the complete bone or of its parts. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
997.
Louis H. A. Prins Armand de Vries Mino R. Caira Douglas W. Oliver Sandra van Dyk Sarel F. Malan 《Journal of chemical crystallography》2008,38(9):705-709
Abstract Polycyclic hydrocarbon compounds exhibit a wide variety of biological activities, ranging from antiviral to Parkinson’s disease.
Several structures such as the adamantanes have reached clinical status and are used therapeutically to treat, amongst others,
neurodegenerative disorders such as Alzheimer’s. Polycyclics have also been utilised as carrier molecules to facilitate entry
of drugs into the brain. The synthesis, molecular and crystal structure of a new polycyclic compound, 3-hydroxy-4-aza-8-oxoheptacyclo[9.4.1.02,10.03,14.04,9.09,13.012,15]tetradecane, are reported. NMR spectroscopy was applied for structure elucidation of the novel compound and a rearrangement
mechanism is proposed for its formation. This compound crystallises in the orthorhombic system, space group Pbca (no. 61). The unit cell parameters are: a = 12.3763 (7), b = 11.6597 (6), c = 15.0539 (8) ?,
V = 2172.3 (2) ?3
, and Z = 8 molecules in the unit cell. The reported structure was confirmed by X-ray analysis, which showed that the title molecules
associate into centrosymmetric dimers via N–H···O hydrogen bonding.
Index Abstract The synthesis and structure of a new polycyclic compound, 3-hydroxy-4-aza-8-oxoheptacyclo[9.4.1.02,10.03,14.04,9.09,13.012,15]tetradecane, are reported in this article.
相似文献
998.
999.
Fernando Rascón-Cruz Sandra González-Gallardo Miguel A. Muñoz-Hernández Rubén A. Toscano Verónica García-Montalvo 《Journal of chemical crystallography》2009,39(7):530-534
Abstract Synthesis and X-ray structural determination of three phosphorus compounds are reported. (3b) is monoclinic P2(1)/c with a = 11.852(1), b = 12.825(1), c = 12.445(1) ?, β = 103.693(1)o; (4a) and (4b) are monoclinic P2(1)/n with a = 12.1422(16), b = 9.0860(12), c = 14.845(2) ?, β = 96.498(3)o for (4a), and a = 12.2714(16), b = 9.2812(12), c = 14.800(2) ?, β = 97.176(2)o for (4b). They all exhibit distorted tetrahedral geometry about the P atom. Ph2P(X)NHC7H7 (X=S (4a) and X=Se (4b)) show typical P–S and P–Se double bond distances and P–N single bonds, while P–S bond in 1-Ad2P(S)Cl (3b) is comparable to P–S single bonded probably due to the largeness of 1-adamantyl groups.
Graphical Abstract Synthesis and X-ray structural determination of 1-Ad2P(S)Cl (3b), Ph2P(S)NHC7H7 (4a) and Ph2P(Se)NHC7H7 (4b) are reported.
相似文献
1000.
Fielding AJ Usselman RJ Watmough N Simkovic M Frerman FE Eaton GR Eaton SS 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2008,190(2):222-232
Electron transfer flavoprotein-ubiquinone oxidoreductase (ETF-QO) is a membrane-bound electron transfer protein that links primary flavoprotein dehydrogenases with the main respiratory chain. Human, porcine, and Rhodobacter sphaeroides ETF-QO each contain a single [4Fe-4S](2+,1+) cluster and one equivalent of FAD, which are diamagnetic in the isolated enzyme and become paramagnetic on reduction with the enzymatic electron donor or with dithionite. The anionic flavin semiquinone can be reduced further to diamagnetic hydroquinone. The redox potentials for the three redox couples are so similar that it is not possible to poise the proteins in a state where both the [4Fe-4S](+) cluster and the flavoquinone are fully in the paramagnetic form. Inversion recovery was used to measure the electron spin-lattice relaxation rates for the [4Fe-4S](+) between 8 and 18K and for semiquinone between 25 and 65K. At higher temperatures the spin-lattice relaxation rates for the [4Fe-4S](+) were calculated from the temperature-dependent contributions to the continuous wave linewidths. Although mixtures of the redox states are present, it was possible to analyze the enhancement of the electron spin relaxation of the FAD semiquinone signal due to dipolar interaction with the more rapidly relaxing [4Fe-4S](+) and obtain point-dipole interspin distances of 18.6+/-1A for the three proteins. The point-dipole distances are within experimental uncertainty of the value calculated based on the crystal structure of porcine ETF-QO when spin delocalization is taken into account. The results demonstrate that electron spin relaxation enhancement can be used to measure distances in redox poised proteins even when several redox states are present. 相似文献