Periodic Fermentor Yield and Enhanced Product Enrichment from Autonomous Oscillations

Four decades of work have clearly established the existence of autonomous oscillations in budding yeast culture across a range of operational parameters and in a few strains. Autonomous oscillations impact substrate conversion to biomass and products. Relatively little work has been done to quantify yield in this case. We have analyzed the yield of autonomously oscillating systems, grown under different conditions, and demonstrate that it too oscillates. Using experimental data and mathematical models of yeast growth and division, we demonstrate strategies to increase the efficient recovery of products. The analysis makes advantage of the population structure and synchrony of the system and our ability to target production within the cell cycle. While oscillatory phenomena in culture have generally been regarded with trepidation in the engineering art of bioprocess control, our results provide further evidence that autonomously oscillating systems can be a powerful tool, rather than an obstruction.     

Studies on the redox properties of the heteropolytungstosilicates substituted by transition elements

The redox properties of the tri-heteropolytungstosilicates of transition elements K_nSiZ(H₂O)W₁₁O₃₉ (Z ? Mn²⁺, Fe³⁺, Co²⁺, Ni²⁺, Zn²⁺, Cd²⁺). In solution have been studied with polarography and cyclic voltammetry as well as with ultraviolet spectroscopy and X-ray photoelectron spectroscopy. The order of the polarographic half-wave potentials (E_1/2) of these heteropolyanions is as follows: Z?Ni²⁺>Co²⁺>Zn²⁺>Fe²⁺>Mn²⁺. We have found that the E_1/2 of heteropolyanions could be correlated linearly with both the electronegativities X of the transition elements and the logarithm of the rate constants (log k_e) of reaction of transition metal ions with hydrated electrons. The reduction mechanism and effects of transition elements on the redox properties of the heteropolyanions have been discussed.     

Completely Entangled State and Simultaneous Eigenstate in a Finite Dimensional Space

It is shown that a completely entangled state belonging to a finite dimensional Hilbert space is equivalent to a simultaneous eigenstate of two unitary operators. These operators are exponentials of sum and difference of two Hermitian operators of a two-mode system that are complementary with each other.     

Sensitivity enhancement of CE and CE-MS for the analysis of peptides by a dynamic pH junction

An analytical method of CE-MS and CE with an online preconcentration technique induced by a dynamic pH junction, addition of organic solvent and large volume injection was developed for sensitive determination of peptides in biological samples. Leucine enkephalin, methionine enkephalin, dynorphin A, β-endorphin and angiotensin II were used as model peptides. The optimal online preconcentration conditions were obtained at a sample matrix consisting of 100?mM borate buffer (pH 10.0) with 50% v/v acetonitrile and a BGE containing 1?M formic acid at pH 2.0, along with a 25-cm injection length. Under the optimized conditions, a 4.0×10(3)-1.1×10(4)-fold increase in peak intensity was achieved without degrading the peak shape. This online preconcentration method was applied to analyze the intracellular angiotensin II within the peptides extracted from HL1 cells and approximately increase of 1×10(4)-fold sensitivity was achieved compared to normal condition. Thus, the developed method could be applied to the analysis of various peptides for peptidomics study in biological samples.     

Maxwell方程离散系统的谱分析

主要考虑有限元离散混合时谐Maxwell方程的鞍点线性方程组的谱分析.理论分析显示在一定的条件下相应系数矩阵的特征值是非常聚集的.