The Role of Bioactive Phenolic Compounds on the Impact of Beer on Health

This review reports recent knowledge on the role of ingredients (barley, hop and yeasts), including genetic factors, on the final yield of phenolic compounds in beer, and how these molecules generally affect resulting beer attributes, focusing mainly on new attempts at the enrichment of beer phenols, with fruits or cereals other than barley. An entire section is dedicated to health-related effects, analyzing the degree up to which studies, investigating phenols-related health effects of beer, have appropriately considered the contribution of alcohol (pure or spirits) intake. For such purpose, we searched Scopus.com for any kind of experimental model (in vitro, animal, human observational or intervention) using beer and considering phenols. Overall, data reported so far support the existence of the somehow additive or synergistic effects of phenols and ethanol present in beer. However, findings are inconclusive and thus deserve further animal and human studies.     

Vanadium oxide intercalated with polyelectrolytes: novel layered hybrids with anion exchange properties

Novel anion exchange hybrid materials were developed by the insertion of poly(diallymethylammonium chloride) (PDDACl) and poly(allylamine hydrochloride) (PAHCl) polyelectrolytes into V(2)O(5) interlayer spaces using hydrothermal treatment and were used to host an anionic cyanine dye. A systematic study of the hybrid material synthesis by direct in situ reaction of PDDACl and PAHCl polycations with V(2)O(5) powders showed that the interlayer space of V(2)O(5) expands from 0.44 nm to 1.40 nm and 1.80 nm upon intercalation of PDDACl and PAHCl polyelectrolytes, respectively. X-ray photoelectron spectroscopy and DR UV-Vis-NIR spectroscopy revealed that some V(5+) sites were reduced to V(4+) during the intercalation of the polyelectrolytes, these acted as both charge balancing entities for the negative oxide sheets and carriers for exchange sites located in the V(2)O(5) interlayer space. The interlayer separation is consistent with the existence of coiled conformation of the polycations. The hybrid materials produced [PDDACl](0.24)[PDDA](0.29)V(2)O(5) and [PAHCl](0.28)[PAH](0.47)V(2)O(5), exhibited approximately 45.0% and 37.0% of chloride ions still available for anionic exchange, respectively. These materials were used to encapsulate a cyanine anionic dye. The presence of the dye was evidenced in the [PDDACl](0.24)[PDDA](0.29)V(2)O(5) by significant fluorescence, with emission peak centered at 617 nm.     

Micellization of CTAB in the presence of silicate anions and the exchange between bromide and silicate at the micelle surface: A step to understand the formation of mesoporous molecular sieves at extremely low surfactant and silicate concentrations

The effect of silicate anions, from dilute aqueous tetramethylammonium silicate (TMASi) solutions (0-3.0 mmol L(-1) in silicon), on the formation of hexadecyltrimethylammonium bromide (CTAB) micelles was investigated by means of a series of simple conductivity experiments. These two compounds are used in the preparation of mesoporous silicate molecular sieves. An increase in the monovalent silicate anion concentration decreases the critical micelle concentration (cmc) of CTAB, as might be expected from the decreased repulsive forces between the polar heads of the surfactant molecules. However, the decrease in cmc values is less pronounced than that observed in the presence of bromide ions, suggesting that Br- binds more strongly than Si(OH)3O- at the micelle surface. Through the ion-exchange formalism, a selectivity coefficient for Si(OH)3O-/Br- exchange of 0.30+/-0.03 was estimated from the conductivity data. This value compares well with that of 0.4+/-0.1 also determined in this work by the pyrene fluorescence quenching method. The experimental results were used to rationalize the formation of a surfactant supramolecular-templated mesoporous molecular sieve at extremely low surfactant (0.63 mmol L(-1)) and silicate (4.00 mmol L(-1)) concentrations.     

Composition modulation analysis of InxGa1−xP layers grown on (0 0 1) germanium substrates

The development of new photovoltaic approach to improve costs and efficiencies is focused on the new materials and new technologies. InGaP is, in this sense, a key material for solar conversion. In particular, in the solar concentration approach, this material is part of multiple junction solar cells. Its low lattice mismatch with germanium and its adequate bandgap make it very promising. This paper shows how compositional modulation can affect the InGaP emitter and the AlGaAs tunnel junctions. The influence of the growth conditions, on the compositional modulation and misfit and threading dislocations, in In_0.49Ga_0.51P layers is demonstrated by TEM on purposely grown single InGaP layers. High resolution electron microscopy (HREM) intensity profiles showed no elastic lattice related modulation.     

Study of the effect of the base,the silica and the niobium sources on the [Nb]-MCM-41 synthesized at room temperature

[Nb]-MCM-41 was synthesized at room temperature by varying the base (tetramethylammonium hydroxide or ammonium hydroxide), the silica source (tetraethyl orthosilicate or tetramethyl orthosilicate), the niobium source (ammonium niobium oxalate, NH₄[NbO(C₂O₄)₂(H₂O)₂] · 3H₂O, or potassium niobate, K₈Nb₆O₁₉) and the order of addition of the niobium source (before or after the silica source). These variations were determinant in the amount of niobium incorporated into the framework and in the structural order of the [Nb]-MCM-41 obtained. Only one method led to the formation of [Nb]-MCM-41 with the desired characteristics and active in the epoxidation of cis-cyclooctene with tert-butyl hydroperoxide leading to 19% conversion and 95% selectivity for cyclooctene oxide after 10 h.     

A note on almost Kähler and nearly Kähler submersions

In this paper the integrability of the horizontal distribution of an almost-Kähler or a nearly-Kähler submersion is studied and curvature properties of such submersions are investigated.     

Unusual Hafnium–Pyridylamido/ERn Heterobimetallic Adducts (ERn=ZnR2 or AlR3)

NMR spectroscopy and DFT studies indicate that the Symyx/Dow Hf(IV)–pyridylamido catalytic system for olefin polymerization, [{N^?,N,C_Nph^?}HfMe][B(C₆F₅)₄] ( 1 , Nph=naphthyl), interacts with ER_n (E=Al or Zn, R=alkyl group) to afford unusual heterobimetallic adducts [{N^?,N}HfMe(μ‐C_Nph)(μ‐R)ER_n?1][B(C₆F₅)₄] in which the cyclometalated Nph acts as a bridge between Hf and E. ¹H VT (variable‐temperature) EXSY NMR spectroscopy provides direct evidence of reversible alkyl exchanges in heterobimetallic adducts, with ZnR₂ showing a higher tendency to participate in this exchange than AlR₃. 1‐Hexene/ER_n competitive reactions with 1 at 240 K reveal that the formation of adducts is strongly favored over 1‐hexene polymerization. Nevertheless, a slight increase in the temperature (to >265 K) initiates 1‐hexene polymerization.     

Real‐time Amyloid Aggregation Monitoring with a Photonic Crystal‐based Approach

We propose the application of a new label‐free optical technique based on photonic nanostructures to real‐time monitor the amyloid‐beta 1‐42 (Aβ(1‐42)) fibrillization, including the early stages of the aggregation process, which are related to the onset of the Alzheimer’s Disease (AD). The aggregation of Aβ peptides into amyloid fibrils has commonly been associated with neuronal death, which culminates in the clinical features of the incurable degenerative AD. Recent studies revealed that cell toxicity is determined by the formation of soluble oligomeric forms of Aβ peptides in the early stages of aggregation. At this phase, classical amyloid detection techniques lack in sensitivity. Upon a chemical passivation of the sensing surface by means of polyethylene glycol, the proposed approach allows an accurate, real‐time monitoring of the refractive index variation of the solution, wherein Aβ(1‐42) peptides are aggregating. This measurement is directly related to the aggregation state of the peptide throughout oligomerization and subsequent fibrillization. Our findings open new perspectives in the understanding of the dynamics of amyloid formation, and validate this approach as a new and powerful method to screen aggregation at early stages.     

A straightforward synthetic access to symmetrical glycosyl disulfides and biological evaluation thereof

Symmetrical glycosyl disulfides can be prepared within a few hours from per-O-acetylated precursors via a sequential approach entailing short reactions and no purification of any intermediate. The final thiolate-to-disulfide oxidation step is noticeably accelerated by low amounts of phenyl diselenide under air. Applicability of the strategy to non-saccharidic symmetrical alkyl disulfides has also been examined. A preliminary assay of the cytotoxic activity of symmetrical 1,1'- disulfides was performed on two human tumor cell lines, and a noteworthy activity was recorded for a range of these synthetic compounds.