A novel technique to specifically analyze the secretome of cells and tissues

The secretome of cells and tissues may reflect a broad variety of pathological conditions and thus represents a rich source of biomarkers. The identity of secreted proteins, usually isolated from cell supernatants or body fluids, is hardly accessible by direct proteome analysis, because these proteins are often masked by high amounts of proteins actually not secreted by the investigated cells. Here, we present a novel method for the specific detection of proteins secreted by human tissue specimen as well as cultured cells and chose liver as a model. The method is based on the metabolic labelling of proteins synthesized during a limited incubation period. Then, the cell supernatant is filtered, precipitated, and subjected to two-dimensional gel electrophoresis. Whereas fluorography detected a large number of proteins derived from residual plasma and dead cells, the autoradiographs selectively displayed genuinely secreted proteins. We demonstrate the feasibility of this approach by means of the secretomes of the hepatocellular carcinoma-derived cell line HepG2 and human liver slices. The selective identification of cell- and tissue-specific protein secretion profiles may help to identify novel sets of biomarkers for wide clinical applications.     

Following the rules: Integrating asset allocation and annuitization in retirement portfolios

Financial advisers have developed standardized payout strategies to help Baby Boomers manage their money in their golden years. Prominent among these are phased withdrawal plans offered by mutual funds including the “self-annuitization” or default rules encouraged under US tax law, and fixed payout annuities offered by insurers. Using a utility-based framework, and taking account of stochastic capital markets and uncertain lifetimes, we first evaluate these rules on a stand-alone basis for a wide range of risk aversion. Next, we permit the consumer to integrate these standardized payout strategies at retirement and compare the results. We show that integrated strategies can enhance retirees’ well-being by 25%-50% for low/moderate levels of risk aversion when compared to full annuitization at retirement. Finally, we examine how welfare changes if the consumer is permitted to switch to a fixed annuity at an optimal point after retirement. This affords the retiree the chance to benefit from the equity premium when younger, and exploit the mortality credit in later life. For moderately risk-averse retirees, the optimal switching age lies between 80 and 85.     

The decision rule approach to optimization under uncertainty: methodology and applications

Computational Management Science - Dynamic decision-making under uncertainty has a long and distinguished history in operations research. Due to the curse of dimensionality, solution schemes that...     

Direct potentiometric immunoelectrodes

A method is described to determine Atrazine and its cross-reacting relatives in water, using a previously described graphite based one-way immunoelectrode and any standard millivoltmeter with low input bias current. The new procedure separates the potential measuring step from the incubation step. In this way, the conditions for highly stable potential measurements and for a most effective formation of the hapten (Atrazine) antibody complex can be optimized separately and all imponderable influence from ions in the analyte water is excluded. The limit of detection of such an electrode is some nanogram per liter.Part III: see [4]     

Crystal packing patterns of cyclodextrin inclusion complexes

Cyclodextrin inclusion complexes crystallize in two basically different patterns, the cage and the channel type. The cage type occurs when cyclodextrins are packed crosswise (fishbone) or, if they are packed side-by-side, in layers and adjacent layers are displaced by about one half molecule. In each case, the internal cavity of one cyclodextrin is closed on both sides by neighbouring cyclodextrins. On the other hand, channel complexes are formed if cyclodextrins are stacked like coins in a roll so that cavities line up to produce long channels. In these crystal structures, cyclodextrins can be arranged in head-to-head or head-to-tail mode. In the smaller -cyclodextrin, cage type structures are formed with small, molecular guests whereas long molecular guests and ionic guest molecules induce channel type structures. The latter are generally preferred with the - and -cyclodextrin series which is probably due to the higher tendency for self aggregation in these two members of the cyclodextrin family.Part XXII of the series Topography of Cyclodextrin Inclusion Complexes. For part XXI, see ref. 6.     

Electrolyte-cathode interactions in 5-V lithium-ion cells

The electrolyte/electrode interactions on the anode side of a lithium-ion cell and the formation of the solid electrolyte interphase (SEI) have been investigated intensively in the past and are fairly well understood. Present knowledge about the reactions on the cathode side and the resulting cathode electrolyte interphase (CEI) is less detailed. In this study, the electrolyte/electrode interactions on the surface of the high-voltage cathode material LiNi_0.5Mn_1.5O₄ (LNMO), both bare and FePO₄-coated, were investigated. The gases evolving upon first time charging of the system were investigated using a GC/MS combination. The degradation products included THF, dimethyl peroxide, phosphor trifluoride, 1,3-dioxolane and dimethyl difluor silane, formed in the GC’s column as its coating reacts with HF from the experiments. Although these substances and their formation are in themselves interesting, the absence of many degradation products which have been mentioned in the existing literature is of equal interest. Our results clearly indicate that coating a cathode material can have a major influence on the amount and composition of the gaseous decomposition products in the formation phase.