Size exclusion behavior of polymers in amide solvents

Summary The size exclusion chromatography of neutral polymers and polymers containing ionic groups was investigated using N,N-dimethylacetamide (DMA) as mobile phase. As reported previously for N,N-dimethylformamide (DMF), acrylonitrile polymers containing charges, even those at terminal end groups, showed markedly small retention volumes and multimodal peaks by refractive index and 280 nm UV detectors. In DMA containing small amounts of LiBr the peaks of the ionic polymers were shifted to small retention volumes while neutral polymers with analogous chemical structures did not show the same behavior. As in the case of DMF the peculiarities observed in DMA were attributed to the formation of supramolecular structures by the interaction of the ionic groups in the polymer and the ionic species from DMA decomposition.     

Evaluation of 4-(4-Fluorobenzyl)piperazin-1-yl]-Based Compounds as Competitive Tyrosinase Inhibitors Endowed with Antimelanogenic Effects

There is a considerable attention for the development of inhibitors of tyrosinase (TYR) as therapeutic strategy for the treatment of hyperpigmentation disorders in humans. Continuing in our efforts to identify TYR inhibitors, we describe the design, synthesis and pharmacophore exploration of new small molecules structurally characterized by the presence of the 4-fluorobenzylpiperazine moiety as key pharmacophoric feature for the inhibition of TYR from Agaricus bisporus (AbTYR). Our investigations resulted in the discovery of the competitive inhibitor [4-(4-fluorobenzyl)piperazin-1-yl]-(3-chloro-2-nitro-phenyl)methanone 26 (IC₅₀=0.18 μM) that proved to be ∼100-fold more active than reference compound kojic acid (IC₅₀=17.76 μM). Notably, compound 26 exerted antimelanogenic effect on B16F10 cells in absence of cytotoxicity. Docking analysis suggested its binding mode into AbTYR and into modelled human TYR.     

Constituents and Pharmacological Activities of Myrcia (Myrtaceae): A Review of an Aromatic and Medicinal Group of Plants

Myrcia is one of the largest genera of the economically important family Myrtaceae. Some of the species are used in folk medicine, such as a group known as “pedra-hume-caá” or “pedra-ume-caá” or “insulina vegetal” (insulin plant) that it is used for the treatment of diabetes. The species are an important source of essential oils, and most of the chemical studies on Myrcia describe the chemical composition of the essential oils, in which mono- and sesquiterpenes are predominant. The non-volatile compounds isolated from Myrcia are usually flavonoids, tannins, acetophenone derivatives and triterpenes. Anti-inflammatory, antinociceptive, antioxidant, antimicrobial activities have been described to Myrcia essential oils, while hypoglycemic, anti-hemorrhagic and antioxidant activities were attributed to the extracts. Flavonoid glucosides and acetophenone derivatives showed aldose reductase and α-glucosidase inhibition, and could explain the traditional use of Myrcia species to treat diabetes. Antimicrobial and anti-inflammatory are some of the activities observed for other isolated compounds from Myrcia.     

Preferential orienting to faces in newborns: A temporal–nasal asymmetry.

It has been proposed that newborns' preferential orienting to faces is primarily controlled by a subcortical mechanism. As an index of subcortical, extrageniculate mediation, the asymmetry between the temporal and nasal hemifields was exploited. In Experiment 1, under monocular viewing conditions, newborns were presented with a pattern that had 3 blobs in the appropriate locations for the eyes and the mouth or a pattern that had an inverted position of the blobs. Results showed that newborns preferentially oriented to the facelike pattern only when it was presented in the temporal hemifield. In Experiment 2, both patterns had the blobs in the inverted position. For one pattern the blobs were black, and for the other they were striped. Newborns preferentially oriented to the striped blobs in either hemifield. The results support the hypothesis that in newborns, preference for facelike patterns reflects the activity of a subcortical mechanism. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Power output fluctuations in large scale pv plants: One year observations with one second resolution and a derived analytic model

The variable nature of the irradiance can produce significant fluctuations in the power generated by large grid‐connected photovoltaic (PV) plants. Experimental 1 s data were collected throughout a year from six PV plants, 18 MWp in total. Then, the dependence of short (below 10 min) power fluctuation on PV plant size has been investigated. The analysis focuses on the study of fluctuation frequency as well as the maximum fluctuation value registered. An analytic model able to describe the frequency of a given fluctuation for a certain day is proposed. Copyright © 2010 John Wiley & Sons, Ltd.     

From irradiance to output power fluctuations: the PV plant as a low pass filter

The power generated by large grid‐connected photovoltaic (PV) plants depends greatly on the solar irradiance. This paper studies the effects of the solar irradiance variability analyzing experimental 1‐s data collected throughout a year at six PV plants, totaling 18 MWp. Each PV plant was modeled as a first order filter function based on an analysis in the frequency domain of the irradiance data and the output power signals. An empiric expression which relates the filter parameters and the PV plant size has been proposed. This simple model has been successfully validated precisely determining the daily maximum output power fluctuation from incident irradiance measurements. Copyright © 2011 John Wiley & Sons, Ltd.     

Exploring Molecular Contacts of MUC1 at CIN85 Binding Interface to Address Future Drug Design Efforts

The modulation of protein-protein interactions (PPIs) by small molecules represents a valuable strategy for pharmacological intervention in several human diseases. In this context, computer-aided drug discovery techniques offer useful resources to predict the network of interactions governing the recognition process between protein partners, thus furnishing relevant information for the design of novel PPI modulators. In this work, we focused our attention on the MUC1-CIN85 complex as a crucial PPI controlling cancer progression and metastasis. MUC1 is a transmembrane glycoprotein whose extracellular domain contains a variable number of tandem repeats (VNTRs) regions that are highly glycosylated in normal cells and under-glycosylated in cancer. The hypo-glycosylation fosters the exposure of the backbone to new interactions with other proteins, such as CIN85, that alter the intracellular signalling in tumour cells. Herein, different computational approaches were combined to investigate the molecular recognition pattern of MUC1-CIN85 PPI thus unveiling new structural information useful for the design of MUC1-CIN85 PPI inhibitors as potential anti-metastatic agents.     

Structural properties and self-activated photoluminescence emissions in hydroxyapatite with distinct particle shapes

The understanding on defect-related photoluminescence (PL) properties of hydroxyapatite (HA) particles has a fundamental importance in the technological field for the development of new non-toxic biomedical and optical devices. However, the mechanisms responsible for this intrinsic PL in HA are not completely elucidated in the literature yet. In the present paper, stoichiometric and calcium-deficient HA nano- and micro-particles were synthesized by chemical precipitation. The influence of structural and morphological features on the intrinsic PL and electronic structure of this material were investigated by varying the addition rate of the phosphate precursor (0.15, 7.00 or 600.00 mL/min) and pH (4.5–5.0 or 9.5–10.0) value adopted in the precipitation. The results indicated that the structural order at long- and short-range varied with the synthesis conditions and particle shapes (rods, needles, plates, and rices). The blue and green PL emissions were attributed to defects (bulk, surface and interface) in the samples. These defects promoted the formation of additional energy levels within the band gap, as revealed by using two distinct excitation wavelengths for photoemission measurements. The energies of these wavelengths (~ 3.54 and ~ 2.98 eV at 350 and 415 nm, respectively) were lower than the band gap energies of HA samples (from 5.59 to 5.72 eV). A general model was proposed to explain the occurrence of self-activated PL in HA structure.     

A multiagent system for retrieving bioinformatics publications from web sources

Due to the enormous amount of information available on the Internet, extracting and classifying it has become one of the most important tasks. This principle is valid also while searching for scientific publications. This paper describes a system able to retrieve scientific publications from the Web throughout a text categorization process. To this end, a generic multiagent architecture has been customized according to the requirements imposed by the specific task. Experiments have been performed on publications extracted from BMC Bioinformatics and PubMed digital archives.