A Zinc-Mediated Deprotective Annulation Approach to New Polycyclic Heterocycles

A straightforward approach to new polycyclic heterocycles, 1H-benzo[4,5]imidazo[1,2-c][1,3]oxazin-1-ones, is presented. It is based on the ZnCl₂-promoted deprotective 6-endo-dig heterocyclization of N-Boc-2-alkynylbenzimidazoles under mild conditions (CH₂Cl₂, 40 °C for 3 h). The zinc center plays a dual role, as it promotes Boc deprotection (with formation of the tert-butyl carbocation, which can be trapped by substrates bearing a nucleophilic group) and activates the triple bond toward intramolecular nucleophilic attack by the carbamate group. The structure of representative products has been confirmed by X-ray diffraction analysis.     

A DNA-Encoded Chemical Library Based on Peptide Macrocycles

The synthesis and characterization of a novel DNA-encoded library of macrocyclic peptide derivatives are described; the macrocycles are based on three sets of proteinogenic and non-proteinogenic amino acid building blocks and featuring the use of copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC) reaction for ring closure. The library (termed YO-DEL) which contains 1 254 838 compounds, was encoded with DNA in single-stranded format and was screened against target proteins of interest using affinity capture procedures and photocrosslinking. YO-DEL selections yielded specific binders against serum albumins, carbonic anhydrases and NKp46, a marker of activated Natural Killer cells.     

Impact of Climatic Conditions on the Resveratrol Concentration in Blend of Vitis vinifera L. cvs. Barbera and Croatina Grape Wines

The aim of this work was to investigate the effect of meteorological conditions on resveratrol concentration of red wines produced in Piacenza viticultural region (Italy). In this regard, six representative estates producing Colli Piacentini Gutturnio DOC (a blend of V. vinifera L. cvs. Barbera and Croatina) vintage wines were analysed for trans- and cis-resveratrol over an 8-year period (1998–2005). Grapes were taken from the same vineyard in each estate by using the same enological practices over the entire investigated period. The meteorological conditions corresponding to the production areas were recorded, and bioclimatic indices were calculated as well. Overall, cis-resveratrol concentration was negatively correlated to Huglin index and August mean temperature, whilst positive correlation coefficients were found when considering the Selianinov index and the rainfall of September.     

A Chemometric Investigation on the Functional Potential in High Power Ultrasound (HPU) Processed Strawberry Juice Made from Fruits Harvested at two Stages of Ripeness

This work aimed to investigate the influence of high-power ultrasound (HPU) technology on the stability of bioactive compounds in strawberry juices obtained from fruits with different stages of ripeness (75% vs. 100%) and stored at 4 °C for 7 days. HPU parameters were amplitude (25, 50, 75, and 100%), pulses (50 vs. 100%) and treatment time (5 vs. 10 min). Amplitude and pulse had a significant effect (p ≤ 0.05) on all bioactive compounds except flavonols and hydroxycinnamic acids. The treatment duration of 5 min vs. 10 min had a significant positive impact on the content of anthocyanins, flavonols and condensed tannins, while the opposite was observed for total phenols, whereas no statistically significant effect was observed for hydroxycinnamic acids. The temperature changes during HPU treatment correlated positively with almost all HPU treatment parameters (amplitude, pulse, energy, power, frequency). Optimal parameters of HPU were obtained for temperature changes, where the highest content of a particular group of bioactive compounds was obtained. Results showed that by combining fruits with a certain ripeness and optimal HPU treatment, it would be possible to produce juices with highly preserved bioactive compounds, while HPU technology has prospects for application in functional food products.     

Photons for Photography: A First Diagnostic Approach to Polaroid Emulsion Transfer on Paper in Paolo Gioli’s Artworks

The aim of this research is to study and diagnose for the first time the Polaroid emulsion transfer in the contemporary artist Paolo Gioli’s artworks to provide preliminary knowledge about the materials of his artworks and the appropriate protocols which can be applied for future studies. The spectral analysis performed followed a multi-technical approach first on the mock-up samples created following Gioli’s technique and on one original artwork of Gioli, composed by: FORS (Fiber Optics Reflectance), Raman, and FTIR (Fourier-Transform InfraRed) spectroscopies. These techniques were chosen according to their completely non-invasiveness and no requirement for sample collection. The obtained spectra from FTIR were not sufficient to assign the dyes found in the transferred Polaroid emulsion. However, they provided significant information about the cellulose-based materials. The most diagnostic results were obtained from FORS for the determination of the dye developers present in the mock-up sample which was obtained from Polacolor Type 88 and from Paolo Gioli’s original artwork created with Polacolor type 89.     

Discovery of a monomeric green fluorescent protein sensor for chloride by structure-guided bioinformatics

Chloride is an essential anion for all forms of life. Beyond electrolyte balance, an increasing body of evidence points to new roles for chloride in normal physiology and disease. Over the last two decades, this understanding has been advanced by chloride-sensitive fluorescent proteins for imaging applications in living cells. To our surprise, these sensors have primarily been engineered from the green fluorescent protein (GFP) found in the jellyfish Aequorea victoria. However, the GFP family has a rich sequence space that could already encode for new sensors with desired properties, thereby minimizing protein engineering efforts and accelerating biological applications. To efficiently sample this space, we present and validate a stepwise bioinformatics strategy focused first on the chloride binding pocket and second on a monomeric oligomerization state. Using this, we identified GFPxm163 from GFPxm found in the jellyfish Aequorea macrodactyla. In vitro characterization shows that the binding of chloride as well as bromide, iodide, and nitrate rapidly tunes the ground state chromophore equilibrium from the phenolate to the phenol state generating a pH-dependent, turn-off fluorescence response. Furthermore, live-cell fluorescence microscopy reveals that GFPxm163 provides a reversible, yet indirect readout of chloride transport via iodide exchange. With this demonstration, we anticipate that the pairing of bioinformatics with protein engineering methods will provide an efficient methodology to discover and design new chloride-sensitive fluorescent proteins for cellular applications.

We developed a workflow to identify and apply GFPxm163 as a new green fluorescent protein-based sensor for chloride.     

Effects of Vocal Constitution and Autonomic Stress-Related Reactivity on Vocal Endurance in Female Student Teachers

Several studies revealed a high percentage of voice problems in future teachers. The influence of vocal constitution on the vocal endurance is, however, still unclear. The goal of this study was to evaluate whether the increase of voice fundamental frequency (F0) during teaching is caused by (1) autonomic regulation patterns under stress, (2) anxiety as an emotional factor, or (3) limitations in voice constitution. Thirty-three subjects with either normal voice constitution (n = 15, group 1) or constitutional hypofunction (n = 18, group 2) assessed by voice range profile measurements were enrolled in this study. Furthermore, they underwent a standardized baseline test to register selected autonomic test parameters and were classified into autonomic outlet types (AOT) as proposed by Johannes et al. Later the subjects were examined during 1 hour of teaching (field study). The parameters tested included heart rate, pulse transition time, finger temperature, and voice fundamental frequency. To measure situational anxiety and general anxiety proneness, a state-trait anxiety inventory was taken. Eleven subjects per group were identified as autonomic stable (AOT 1), two per group as responding cardiovascularly (AOT 2), and two of group 1 and four of group 2, respectively, as having higher heart rate and higher blood pressure responses to stress (AOT 4). One subject had to be excluded because of missing data. However, statistical analyses showed no differences between AOT groups regarding the voice constitution groups. Increased fundamental frequencies of speaking voice after 30 and 45 minutes of teaching were found in group 2 (constitutional hypofunction). No effect of state or trait anxiety on voice endurance could be detected. Thus, the increase of fundamental frequency of voice has to be regarded as a consequence of vocal fatigue. A constitutionally weak voice seems to be a risk factor for developing a professional voice disorder.     

Kinematic FE limit analysis homogenization model for masonry walls reinforced with continuous FRP grids

A homogenization model for periodic masonry structures reinforced with continuous FRP grids is presented. Starting from the observation that a continuous grid preserves the periodicity of the internal masonry layer, rigid-plastic homogenization is applied directly on a multi-layer heterogeneous representative element of volume (REV) constituted by bricks, finite thickness mortar joints and external FRP grids. In particular, reinforced masonry homogenized failure surfaces are obtained by means of a compatible identification procedure, where each brick is supposed interacting with its six neighbors by means of finite thickness mortar joints and the FRP grid is applied on the external surfaces of the REV. In the framework of the kinematic theorem of limit analysis, a simple constrained minimization problem is obtained on the unit cell, suitable to estimate – with a very limited computational effort – reinforced masonry homogenized failure surfaces.A FE strategy is adopted at a cell level, modeling joints and bricks with six-noded wedge shaped elements and the FRP grid through rigid infinitely resistant truss elements connected node by node with bricks and mortar. A possible jump of velocities is assumed at the interfaces between contiguous wedge and truss elements, where plastic dissipation occurs. For mortar and bricks interfaces, a frictional behavior with possible limited tensile and compressive strength is assumed, whereas for FRP bars some formulas available in the literature are adopted to reproduce the delamination of the truss from the support.Two meaningful structural examples are considered to show the capabilities of the procedure proposed, namely a reinforced masonry deep beam (0°/90° continuous reinforcement) and a masonry beam in simple flexion for which experimental data are available. Good agreement is found between present model and alternative numerical approaches.