No description available.

In this study we have used isothermal titration calorimetry, ITC, and circular dichroism spectropolarimetry, CD, to directly measure the thermodynamics and the structural changes for binding histones, H11 and H14, to DNA. The ITC data have been used to estimate the binding constant, (K ≈ 108) and the enthalpy change (ΔH ≈ + 5 (H11 at 25ºC), ΔH ≈ +20 kcal/mol (H14 at 15 ºC) for formation of the H1/DNA complex. CD data indicate that both H1 and DNA are partially unfolded in the H1/DNA complex. Protein and DNA unfolding must contribute to the large unfavorable endothermic enthalpy change for complex formation. The ITC data indicate that the H11 binding site is comprised 30 DNA base pairs while H14 interacts with approximately 36 DNA base pairs. At saturation, our data are consistent with 100% of the H1 binding sites being occupied in the H1/DNA complex.

No description available.

Stuttgart, Univ., Diss., 2000.

Thermal properties of ten different seafood were measured in this research. They included bluefish (<i>Pomatomus saltatrix</i>), croaker (<i>Micropogonias undulatus</i>), spanish mackerel (<i>Scomberomorus maculatus</i>), pink salmon (<i>Oncorhynhus gorbuscha</i>), black seabass (<i>Atractoscion nobilis</i>), spot (<i>Leiostomus xanthurus</i>), shrimp(<i>Pandalus borealis</i>), tilapia (<i>Tilapia aurea</i>), grey sea trout(</i>Cynoscion regalis</i>), and yellow fin tuna (<i>Thunnus albacares</i>) (Wheaton, et al. 1985). Thermal properties measured were thermal conductivity, thermal diffusivity, and specific heat from 5 to 30^oC. Enthalpy was measured from -40 to 30^oC. Moisture and fat content were measured. Thermal conductivity and thermal diffusivity were measured by a rapid transient technique using a bead thermistor probe. Specific heat and enthalpy were measured using a differential scanning calorimeter. Moisture content and fat content were measured by the AOAC specified oven dry method and ether extraction method, respectively. The measured thermal properties agreed well with the scarcely available literature values. They were then statistically correlated with moisture and fat content. Based on statistical analysis, mathematical models relating thermal properties and composition were proposed and compared with the models available in the literature. Models for thermal conductivity and specific heat were recommended to predict these properties of meats and fish with similar composition. / Master of Science

Cardiac contraction at the level of the sarcomere is regulated by the thin filament (TF) composed of actin, alpha tropomyosin (TPM), and the troponin (Tn) complex (cTnT: cTnC: cTnI). The "gate-keeper" protein, α-TPM, is a highly conserved α-helical, coiled-coil dimer that spans actin and regulates myosin-actin interactions. The N-terminus of one α-TPM dimer inter-digitates with the C-terminus of the adjacent dimer in a head-to-tail fashion forming the flexible and cooperative TPM-overlap that is necessary for myofilament activation. Two dilated cardiomyopathy (DCM) causing mutations in TPM (D84N and D230N) and one hypertrophic cardiomyopathy (HCM) causing mutation (E62Q), all identified in large, unrelated, multigenerational families, were utilized to study how primary alterations in protein structure cause functional deficits. We hypothesize that structural changes from a single point mutation propagate along the -helical coiled-coil of TPM, thus affecting its regulatory function. Structural effects of the mutations studied via differential scanning calorimetry (DSC) on TPM alone revealed significant changes in the thermal unfolding temperatures of both the C- and N-termini for all mutants compared to WT, indicating that mutational effects propagate to both ends of TPM, thus affecting the overlap region. Although, of note, the proximal termini to the mutation has shown more significant structural changes compared to WT. DSC analysis on fully reconstituted TF’s (Tn:TPM:Actin) revealed effects on the TPM-Actin cooperativity of activation, affecting interaction strength (thermal stability), and the rigidity of TPM moving along actin (FWHM). To characterize the resultant functional effect of these discrete changes in thermal stability and TPM rigidity, ATPase assays were used to measure actomyosin activation in the presence and absence of Ca2+. Together, these data will provide a molecular level understanding of the structural and functional deficits caused by these mutations to help elucidate the mechanisms leading to disease.

Zugl.: Halle (Saale), Univ., Diss., 2008

Stuttgart, Univ., Diss., 2000.

This study presents results on the use of ellipsometry as a novel probe for thin films of a diblock copolymer. Ellipsometry makes use of the change in polarisation induced upon reflection of light from a film covered substrate to enable calculation of the refractive index and thickness of the film. The infom1ation obtained in these measurements can be compared to differential scanning calorimetry, with the additional advantages that small sample volumes and slow cooling rates can be employed, and expansion coefficients can be determined. The work is presented in two parts; first crystallisation within the phase-separated domains is studied, then a morphological transition in the diblock ordering is characterised. By studying the temperature dependence of the film thickness and refractive index, crystallisation kinetics within very small volumes( 10^-10 L) of a poly (butadiene-b-ethylene oxide) diblock copolymer are measured. Through a comparison of two different PEO block lengths, a reduction in both the crystallisation and melting temperatures is demonstrated as the domain volume is decreased. Upon cooling, an additional transition is observed. We ascribe this to a morphological transition from a layer of ordered spheres to a lamellar layer at the substrate, which is consistent with a comparison between the data and simulated ellipsometry data. The sensitivity of ellipsometry makes it a well suited and versatile technique for probing thin film kinetics in diblock copolymers. / Thesis / Bachelor of Science (BSc)

No / The present study demonstrates the application of decision tree algorithms to the co-crystallization process. Fifty four (54) batches of carbamazepine–salicylic acid co-crystals embedded in poly(ethylene oxide) were manufactured via hot melt extrusion and characterized by powder X-ray diffraction, differnetial scanning calorimetry, and near-infrared spectroscopy. This dataset was then applied in WEKA, which is an open-sourced machine learning software to study the effect of processing temperature, screw speed, screw configuration, and poly(ethylene oxide) concentration on the percentage of co-crystal conversion. The decision trees obtained provided statistically meaningful and easy-to-interpret rules, demonstrating the potential to use the method to make rational decisions during the development of co-crystallization processes.