ABSTRACT
The molecular parameters that govern charge transport in anthradithiophene (ADT) are studied by a joint experimental/theoretical approach involving high-resolution gas-phase photoelectron spectroscopy and quantum-mechanical methods. The hole reorganization energy of ADT has been determined by an analysis of the vibrational structure of the lowest ionization band in the gas-phase photoelectron spectrum as well as by density-functional theory calculations. In addition, various dimers and clusters of ADT molecules have been considered in order to understand the effect of molecular packing on the hole and electron intermolecular transfer integrals. The results indicate that the intrinsic electronic structure, the relevant intramolecular vibrational modes, and the intermolecular interactions in ADT are very similar to those in pentacene.
Subject(s)
Electrons , Heterocyclic Compounds, 4 or More Rings/chemistry , Thiophenes/chemistry , Dimerization , Hydrogen Bonding , Models, Chemical , Models, Molecular , Models, Statistical , Molecular Conformation , Molecular Structure , Spectrum AnalysisABSTRACT
In 1997, over four thousand people on organ waiting lists lost their lives. The current organ shortage has led to the need to find alternative sources of organs for transplantation. Advances in immunosuppressive therapies and genetics have made xenotransplantation, the transplantation of animal organs into humans, an increasingly viable technology. However, the promise of xenotransplantation is tempered by the unspecified amount of risk that zoonotic pathogens could mutate and infect humans with potentially deadly diseases.
Subject(s)
Disease Transmission, Infectious/prevention & control , Transplantation, Heterologous/adverse effects , Animals , Federal Government , Government Regulation , Humans , Informed Consent , Public Health , Quarantine , Registries , Specific Pathogen-Free Organisms , Swine , Transplantation, Heterologous/economics , Transplantation, Heterologous/standards , United States , ZoonosesABSTRACT
The morphological and biochemical adaptations of knee meniscus to prolonged exercise were studied. Female Sprague-Dawley rats maintained under controlled environmental conditions were randomly assigned to either an endurance-trained or a sedentary group. Training consisted of a progressive exercise protocol on a motor-driven treadmill, 5 days/wk for 12 wk. Knee lateral menisci were obtained from anesthetized rats and used for morphological and biochemical analyses. Gastrocnemius succinate dehydrogenase increased 65% in the endurance-trained group, as evidence for a training effect. In the trained group, collagen, proteoglycan, and calcium concentrations increased significantly in the posterior region of the lateral meniscus. In contrast, no significant changes were found in the anterior region of the lateral meniscus. The region-specific changes in meniscal concentrations of calcium and matrix macromolecules in response to prolonged exercise are consistent with the distinctly different mechanical properties and functional roles of the anterior and posterior regions of the rat knee meniscus.
Subject(s)
Adaptation, Physiological , Cartilage, Articular/physiology , Knee Joint/physiology , Physical Exertion , Animals , Calcium/metabolism , Cartilage, Articular/anatomy & histology , Cartilage, Articular/metabolism , Female , Hydroxyproline/metabolism , Knee Joint/anatomy & histology , Knee Joint/metabolism , Rats , Time Factors , Uronic Acids/metabolismABSTRACT
We established quantitative histochemical assays for the enzymatic activity of succinate dehydrogenase and alpha-glycerol phosphate dehydrogenase for cat skeletal muscle. A computer-enhanced image analysis system was used to quantitate the histochemical enzyme-activity reaction products. We describe a series of experiments that verify the reliability and validity of the assays. Histochemically determined enzyme activities were linear with respect to tissue thickness and reaction time. Biochemically determined enzyme activities were also linear with respect to tissue thickness and incubation time. Consecutive tissue sections, assayed either histochemically or biochemically, were used to establish a linear regression equation that allowed quantitative histochemically determined reaction rates, measured in optical density per minute, to be calibrated as nanomoles per minute.
Subject(s)
Glycerolphosphate Dehydrogenase/analysis , Muscles/enzymology , Succinate Dehydrogenase/analysis , Animals , Cats , Histocytochemistry , Spectrometry, Fluorescence , Time FactorsABSTRACT
The effects of an acute injection of synthetic salmon calcitonin (sCT) and human CT (hCT) and of long term (4-month) administration of sCT on serum glucose levels were investigated in eight patients with Paget's disease of bone. The results obtained demonstrate a small but statistically significant rise in serum glucose after a single sc injection of synthetic hCT. However, the serum glucose level was not increased after 4 months of daily administration of synthetic sCT to our pagetic patients. Our results also substantiate the clinical observation that long term administration of CT does not cause clinical diabetes or significantly change fasting blood glucose concentration. Our results are also consistent with the view that the effect of CT administration on glucose metabolism is related to the secondary hypocalcemia.
