STUDIES ON PLANT BILE PIGMENTS-6. PHOTOCHEMICALLY ASSISTED REACTION OF A-DIHYDROBILINDIONE WITH NUCLEOPHILES AS A MODEL FOR PHYTOCHROME INTERCONVERSION

From the A-dihydrobilindione 3. the pyridinium derivatives 6a,b and analogues thereof have been obtained by a formal nucleophilic substitution. The reaction is rationalized as a photochemically assisted oxidation of 3 with a subsequent regioselective addition of pyridine at C-5. By thermolysis. 6a.b yields back the parent bilin 3, together with an oxidation product. The significance of the reaction with respect to the phytochrome interconversion is discussed

PHYCOBILISOMES AND ISOLATED PHYCOBILIPROTEINS. EFFECT OF GLUTARDIALDEHYDE AND BENZOQUINONE ON FLUORESCENCE

The fluorescence of the biliproteins C-phycocyanin from Spirulina platensis, B-phycoerythrin from Porphyridium cruentum and of isolated whole P. cruentum phycobilisomes is quenched in the presence of glutardialdehyde (GA) or benzoquinone (BQ). The kinetics of fluorescence decrease thus induced is biphasic. If GA is used as a quencher, the fluorescence can be recovered at 77 K. Contrary to the GA-effect, only a minor recovery takes place with BQ at 77K, thus demonstrating a different mechanism of action of GA and BQ on biliprotein

The Utah Model: Lessons for Regional Planning

Utah has become an unlikely leader in regional planning through a voluntary partnership of key leaders, agencies, local government, and the general public. Given that regional planning efforts around the nation have generally evoked strong reactions from residents concerned about losing local control, the success of Envision Utah—the organization that emerged as a key driver of regional planning in Utah—in building a consensus around regional growth management holds lessons for other regions. Envision Utah adopted several strategies that have distinguished Utah’s regional planning efforts from other regions and given rise to what can be called the “Utah model” of collaborative planning. Envision Utah found success by not only tapping into people’s shared values and aspirations, but also because of its significant public engagement, use of convincing, unbiased data to demonstrate the need to work regionally, and ability to garner broad buy‐in from important stakeholders in the community. As more is learned from Envision Utah’s success in regional coordination, a number of takeaways appear relevant for other regions: Pay attention to the sustainability and capacity of the leading organization Arm the public with clear data and analysis, skillfully marketed Package all proposals and principles to appeal to the values of the community Spend time initiating and maintaining the right political setu

Polymer Dissolution Model: An Energy Adaptation Of The Critical Ionization Theory

The current scale of features size in the microelectronics industry has reached the point where molecular level interactions affect process fidelity and produce excursions from the continuum world like line edge roughness (LER). Here we present a 3D molecular level model based on the adaptation of the critical ionization (CI) theory using a fundamental interaction energy approach. The model asserts that it is the favorable interaction between the ionized part of the polymer and the developer solution which renders the polymer soluble. Dynamic Monte Carlo methods were used in the current model to study the polymer dissolution phenomenon. The surface ionization was captured by employing an electric double layer at the interface, and polymer motion was simulated using the Metropolis algorithm. The approximated interaction parameters, for different species in the system, were obtained experimentally and used to calibrate the simulated dissolution rate response to polymer molecular weight and developer concentration. The predicted response is in good agreement with experimental dissolution rate data. The simulation results support the premise of the CI theory and provide an insight into the CI model from a new prospective. This model may provide a means to study the contribution of development to LER and other related defects based on molecular level interactions between distinct components in the polymer and the developer.Chemical Engineerin

Conduction Channels of One-Atom Zinc Contacts

We have determined the transmission coefficients of atomic-sized Zn contacts using a new type of breakjunction which contains a whisker as a central bridge. We find that in the last conductance plateau the transport is unexpectedly dominated by a well-transmitting single conduction channel. We explain the experimental findings with the help of a tight-binding model which shows that in an one-atom Zn contact the current proceeds through the 4s and 4p orbitals of the central atom.Comment: revtex4, 5 pages, 5 figure