Lipophilization of dihydrocaffeic acid affects its antioxidative properties in fish‐oil‐enriched emulsions

The aim of the present study was to evaluate the antioxidative effect of lipophilized dihydrocaffeic acid, i.e., octyl dihydrocaffeate and oleyl dihydrocaffeate. Furthermore, the relationship between the measured efficacy of the antioxidants in emulsions, their partitioning into different phases of an emulsion system and their in vitro antioxidant properties was also evaluated. Lipid oxidation in the emulsions was affected by the antioxidants applied. Thus, despite a reduced antioxidant activity of lipophilized dihydrocaffeic acid in the antioxidant assays, lipophilized dihydrocaffeic acid was more efficient than caffeic and dihydrocaffeic acids. Octyl dihydrocaffeate had a significantly higher antioxidative effect than oleyl dihydrocaffeate in emulsions. The results partly supported the polar paradox hypothesis, since lipophilized compounds resulted in increased oxidative stability. However, the decreased antioxidative efficacy with increasing alkyl chain length esterified to dihydrocaffeic acid supported a newly suggested cut‐off effect hypothesis. This hypothesis suggests that when a certain level of hydrophobicity is obtained for lipophilized phenolic acids, the ester forms micelles in the aqueous phase rather than being located at the interface or oil phase. This phenomenon is suggested to explain the reduced antioxidant activity of oleyl dihydrocaffeate compared with octyl dihydrocaffeate. Practical application: The finding that lipophilization of phenolic compounds increase their efficacy opens up new possibilities for producing new and more efficient antioxidants for food systems. However, the results also show that optimization of the chain length for each type of phenolic compound may be necessary. Since these compounds may have a much higher efficacy against lipid oxidation a lower amount of antioxidant will be necessary to obtain the same effect. This would decrease the costs. In addition, the use of synthetic antioxidants, that might have toxic effect in vivo, can be avoided. The raw materials used for the lipophilized compounds are natural compounds, however the fate of the lipophilized compounds in vivo should eventually be evaluated.     

Emerging hiPSC Models for Drug Discovery in Neurodegenerative Diseases

Neurodegenerative diseases affect millions of people worldwide and are characterized by the chronic and progressive deterioration of neural function. Neurodegenerative diseases, such as Alzheimer’s disease (AD), Parkinson’s disease (PD), amyotrophic lateral sclerosis (ALS), and Huntington’s disease (HD), represent a huge social and economic burden due to increasing prevalence in our aging society, severity of symptoms, and lack of effective disease-modifying therapies. This lack of effective treatments is partly due to a lack of reliable models. Modeling neurodegenerative diseases is difficult because of poor access to human samples (restricted in general to postmortem tissue) and limited knowledge of disease mechanisms in a human context. Animal models play an instrumental role in understanding these diseases but fail to comprehensively represent the full extent of disease due to critical differences between humans and other mammals. The advent of human-induced pluripotent stem cell (hiPSC) technology presents an advantageous system that complements animal models of neurodegenerative diseases. Coupled with advances in gene-editing technologies, hiPSC-derived neural cells from patients and healthy donors now allow disease modeling using human samples that can be used for drug discovery.     

Synergy Versus Potency in the Defensive Secretions from Nymphs of two Pentatomomorphan Families (Hemiptera: Coreidae and Pentatomidae)

One characteristic of true bugs (Heteroptera) is the presence of dorsal abdominal glands in the immature nymphal stages. These glands usually produce defensive chemicals (allomones) that vary among taxa but are still similar in closely related groups. Knowledge of the chemistry and prevalence of allomones in different taxa may clarify the evolution of these chemical defensive strategies. Within the infraorder Pentatomomorpha, the known secretions of nymphs of Pentatomidae tend to contain the hydrocarbon, n-tridecane, a keto-aldehyde, and an (E)-2-alkenal as the most abundant components. In the Coreidae, the dorsal abdominal gland secretions of nymphs often contain little or no hydrocarbon, and the most abundant keto-aldehyde and (E)-2-alkenal are often of shorter chain-length than those of pentatomids. We hypothesized that the long chain compounds would be less potent than their shorter homologs, and that bugs that carry the former would benefit from a synergistic effect of n-tridecane. To test this hypothesis we used three different behavioral assays with ants. A predator?Cprey assay tested the deterrence of allomones toward predators; a vapor experiment tested the effectiveness of allomones in the gaseous phase toward predators; and application of allomones onto predators tested the effect of direct contact. The results substantiate the hypothesis of a synergistic effect between n-tridecane and longer chain keto-aldehyde and (E)-2-alkenal in deterring predators. The short chain keto-aldehyde 4-oxo-(E)-2-hexenal was highly effective on its own. Thus, it seems that different groups of the infraorder diverged in their strategies involving defensive chemicals. Implications of this divergence are discussed.     

Robust and Selective Metathesis Catalysts for Oleochemical Applications

The screening of known ruthenium alkylidene complexes in the ethenolysis of methyl oleate shows that the Grubbs-type Ru-catalysts bearing two phosphine donor ligands exhibit high selectivity for the formation of terminal olefins. Second-generation ruthenium catalysts promote almost the exclusive formation of self-metathesis products. Complexes with chelating alkylidene moieties (Hoveyda-type) generally exhibit poor selectivity for both ethenolysis and self-metathesis products. Complexes 2b and 2d promote self-metathesis of methyl oleate with catalyst loading of 2?ppm without significant isomerization up to 110?°C (using 2d) and up to 150?°C (using 2b).     

Language-driven concept learning: Deciphering Jabberwocky.

Four experiments assessed (Whorfian) effects of language on acquiring event categories. During learning, English-like spoken language accompanied animated scenes in some conditions. Lexical (novel verbs) and/or syntactic cues (either argument structures or prepositions) covaried with event category. Other conditions provided no language. All participants' knowledge of event categories was tested without language. Participants learned the event categories better when some aspect of language covaried with them (Experiments 1, 2, & 3; but not with sounds, Experiment 4), and better still when two aspects of language covaried (Experiments 1 & 3). However, multiple (Experiments 2 & 3) and individual language cues (Experiment 4) did not always facilitate learning. The effect of language is more complicated than providing feedback, as in supervised learning, or increasing systematicity, as in unsupervised learning. Language form induced specific expectations, with effects on learning analogous to the effects of prior theories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Strategies for oxidation catalyzed by polyoxometalates at the interface of homogeneous and heterogeneous catalysis

A basic premise behind the use of polyoxometalates in oxidation chemistry is the fact that polyoxometalates are oxidatively stable. This, a priori, leads to the conclusion that for practical purposes polyoxometalates would have distinct advantages over widely investigated organometallic compounds that are vulnerable to decomposition due to oxidation of the ligand bound to the metal center. Since polyoxometalate synthesis is normally carried out in water by mixing the stoichiometrically required amounts of monomeric metal salts and adjusting the pH to a specific acidic value many structure types are accessible by variation of the reaction stoichiometry, replacement of one or more addenda atoms with other transition or main group metals, and pH control. The structural variety available has enabled the use of polyoxometalates as catalysts for oxidation of hydrocarbons and functionalized organic substrates (alcohols, amines, sulfides, etc.) with a wide range of oxygen donors ranging from molecular oxygen, hydrogen peroxide, nitrous oxide, ozone, alkyl hydroperoxides, periodate, sulfoxide and others. The wide purview of oxidation reactions is enabled because the structural variety leads to oxidation through a number of different mechanistic motifs.From a synthetic organic point of view, the most applicable uses of polyoxometalates as catalysts involve the green oxygen donors – hydrogen peroxide and molecular oxygen. Since practical applications are in hand in this area, practical considerations concerned with catalyst recycle and/or recovery and the elimination of environmentally problematic solvents are also coming to the forefront. In this paper, we will present some of our activities in the area of catalyst engineering for catalytic synthetic applications by polyoxometalates including: (a) catalytic mesoporous solids from organic-polyoxometalate hybrid materials, (b) fluorous phase polyoxometalates with and without fluorous solvents and (c) the use of aqueous biphasic media for oxidation with hydrogen peroxide.     

Reverse-phase protein arrays for application-orientated cancer research

A detailed and quantitative analysis of disease-relevant signaling will greatly contribute to our understanding of tumorigenesis and cancer progression, and thus open new strategies for drug discovery. However, throughput and sensitivity of currently established methods available for proteome profiling do not comply with the needs of clinical research such as high sample capacity and low sample consumption. Protein microarrays emerged as a promising alternative to analyze the abundance of proteins and their phosphorylation status on a high-throughput level. Here we summarize recent methodological advancements in the field of reverse-phase protein arrays and demonstrate their potential for clinical research as well as for in vitro applications.     

A Polynomial Quantum Algorithm for Approximating the Jones Polynomial

The Jones polynomial, discovered in 1984, is an important knot invariant in topology. Among its many connections to various mathematical and physical areas, it is known (due to Witten) to be intimately connected to Topological Quantum Field Theory ( ). The works of Freedman, Kitaev, Larsen and Wang provide an efficient simulation of by a quantum computer, and vice versa. These results implicitly imply the existence of an efficient (namely, polynomial) quantum algorithm that provides a certain additive approximation of the Jones polynomial at the fifth root of unity, e ^{2π i/5}, and moreover, that this problem is -complete. Unfortunately, this important algorithm was never explicitly formulated. Moreover, the results of Freedman et al. are heavily based on , which makes the algorithm essentially inaccessible to computer scientists. We provide an explicit and simple polynomial quantum algorithm to approximate the Jones polynomial of an n strands braid with m crossings at any primitive root of unity e ^{2π i/k} , where the running time of the algorithm is polynomial in m, n and k. Our algorithm is based, rather than on , on well known mathematical results (specifically, the path model representation of the braid group and the uniqueness of the Markov trace for the Temperley-Lieb algebra). By the results of Freedman et al., our algorithm solves a complete problem. Our algorithm works by encoding the local structure of the problem into the local unitary gates which are applied by the circuit. This structure is significantly different from previous quantum algorithms, which are mostly based on the Quantum Fourier transform. Since the results of the current paper were presented in their preliminary form, these ideas have been extended and generalized in several interesting directions. Most notably, Aharonov, Arad, Eban and Landau give a simplification and extension of these results that provides additive approximations for all points of the Tutte polynomial, including the Jones polynomial at any point, and the Potts model partition function at any temperature and any set of coupling strengths. We hope and believe that the ideas presented in this work will have other extensions and generalizations.     

Air-drying of human leucocytes for scanning electron microscopy using the GTGO procedure

The utilization of tannic acid and guanidine hydrochloride as mordants for better osmium binding has been shown to serve as an excellent alternative to metal coating of organ tissue specimens for scanning electron microscopy (SEM). The present report describes the GTGO procedure, a modification of the TAO technique introduced by Murakami et al. (1977, 1978), which we have found successful for the preparation of air dried peripheral blood leucocytes for SEM studies. Air dried, GTGO-treated leucocytes show excellent preservation of surface features with minimal cell shrinkage. When critical point dried, GTGO-treated cells are examined, they also show less shrinkage than cells prepared with standard glutaraldehyde fixation and critical point drying. The potential application of this air drying procedure (GTGO-AD) to other soft biological specimens is currently under investigation. This technique is recommended as a new and effective air drying procedure for the successful preparation of cells for SEM.