914 resultados para cyclic movements
Resumo:
Periodic leg movements (PLM) during sleep consist of involuntary periodic movements of the lower extremities. The debated functional relevance of PLM during sleep is based on correlation of clinical parameters with the PLM index (PLMI). However, periodicity in movements may not be reflected best by the PLMI. Here, an approach novel to the field of sleep research is used to reveal intrinsic periodicity in inter movement intervals (IMI) in patients with PLM.
Resumo:
Targeting of cholecystokinin receptor expressing malignancies such as medullary thyroid carcinoma is currently limited by low in vivo stability of radioligands. To increase the stability, we have developed and preclinically evaluated two cyclic 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-minigastrin analogs radiolabeled with (111)In and (68)Ga.
Resumo:
Undergraduate research in chemistry provides not only a meaningful experience for the students, but is essential in getting research done. This talk will focus on an ongoing project in my lab: designing large molecules of specific shapes by studying the fundamental reactions. While results will be discussed, the talk will be tailored towards a general audience. I will attempt to highlight the outstanding contributions made by Bucknell students that have worked in my lab.
Resumo:
Full geometry optimizations using the PM3, AM1, 3-21G∗/HF and 6-31G∗/HF levels of theory were conducted on the syn and anti conformations of cyclic3′,5′-adenosine monophosphate (cAMP). Comparison of the anti crystal structures with the semiempirical and ab initio results revealed that the ab initio results agree well with the experimental results. The results of semiempirical calculations are in qualitative agreement with experimental and ab initio values, with the exception of the glycosyl torsion angle for the anti conformer. Sugar puckering, which is not handled properly by semiempirical methods for unconstrained sugars, nucleosides, nucleotides and nucleotide base pairs, is modeled reasonably well by the semiempirical methods for cAMP. This improvement results from the constraints introduced by the cyclization of AMP to form the phosphodiester.
Resumo:
The supermolecule approach has been used to model the hydration of cyclic 3‘,5‘-adenosine monophosphate, cAMP. Model building combined with PM3 optimizations predict that the anti conformer of cAMP is capable of hydrogen bonding to an additional solvent water molecule compared to the syn conformer. The addition of one water to the syn superstructure with concurrent rotation of the base about the glycosyl bond to form the anti superstructure leads to an additional enthalpy of stabilization of approximately −6 kcal/mol at the PM3 level. This specific solute−solvent interaction is an example of a large solvent effect, as the method predicts that cAMP has a conformational preference for the anti isomer in solution. This conformational preference results from a change in the number of specific solute−solvent interactions in this system. This prediction could be tested by NMR techniques. The number of waters predicted to be in the first hydration sphere around cAMP is in agreement with the results of hydration studies of nucleotides in DNA. In addition, the detailed picture of solvation about this cyclic nucleotide is in agreement with infrared experimental results.
Resumo:
The recent rise of the Tea Party movement has added a new dimension to our discussion of domestic politics. The main question is: what effect will the Tea Party have on the political landscape? The best way to answer this question is to place the Tea Party in historical and theoretical context, in order to discuss what type of social movement the Tea Party is and what impact it might have. To this end, I will define and discuss the two major literatures in socialmovement theory: Issue Evolution and Political Process theory. This theoretical framework will provide the basis for a more concrete definition of the Tea Party movement itself. I will attemptto define the Tea Party movement based on its demographics, goals and political successes and will discuss it within the context of this theoretical framework. In addition, I will discuss four landmark social movements within our country’s history through the lens of the theoretical framework. I have found that successful movements rely on a combination of internal organizations and networks and external political opportunities to achieve and maintain nationalrelevance. In the end, I will come to the conclusion that the Tea Party will not likely have a major lasting impact on the political arena. It lacks key parts of the internal structure that makes some movements, such as the Civil Rights movement, so influential. But in the short term it will succeed in pushing the Republican Party towards a more fiscally conservative position.
Resumo:
The purpose of this study was to characterize the nature of the relation between periodic leg movements during sleep (PLMS) and cortical arousals to contribute to the debate on the clinical significance and treatment of PLMS.