Molecularly imprinted polymers: present and future prospective

Molecular Imprinting Technology (MIT) is a technique to design artificial receptors with a predetermined selectivity and specificity for a given analyte, which can be used as ideal materials in various application fields. Molecularly Imprinted Polymers (MIPs), the polymeric matrices obtained using the imprinting technology, are robust molecular recognition elements able to mimic natural recognition entities, such as antibodies and biological receptors, useful to separate and analyze complicated samples such as biological fluids and environmental samples. The scope of this review is to provide a general overview on MIPs field discussing first general aspects in MIP preparation and then dealing with various application aspects. This review aims to outline the molecularly imprinted process and present a summary of principal application fields of molecularly imprinted polymers, focusing on chemical sensing, separation science, drug delivery and catalysis. Some significant aspects about preparation and application of the molecular imprinting polymers with examples taken from the recent literature will be discussed. Theoretical and experimental parameters for MIPs design in terms of the interaction between template and polymer functionalities will be considered and synthesis methods for the improvement of MIP recognition properties will also be presented.     

Urolithin as a converging scaffold linking ellagic acid and coumarin analogues: design of potent protein kinase CK2 inhibitors

Casein kinase 2 (CK2) is a ubiquitous, essential, and highly pleiotropic protein kinase; its abnormally high constitutive activity is suspected to underlie its pathogenic potential in neoplasia and other relevant diseases. Previously, using different in silico screening approaches, two potent and selective CK2 inhibitors were identified by our group: ellagic acid, a naturally occurring tannic acid derivative (K(i)=20 nM) and 3,8-dibromo-7-hydroxy-4-methylchromen-2-one (DBC, K(i)=60 nM). Comparing the crystallographic binding modes of both ellagic acid and DBC, an X-ray structure-driven merging approach was taken to design novel CK2 inhibitors with improved target affinity. A urolithin moiety is proposed as a possible bridging scaffold between the two known CK2 inhibitors, ellagic acid and DBC. Optimization of urolithin A as the bridging moiety led to the identification of 4-bromo-3,8-dihydroxy-benzo[c]chromen-6-one as a novel, potent and selective CK2 inhibitor, which shows a K(i) value of 7 nM against the protein kinase, representing a significant improvement in affinity for the target compared with the two parent fragments.     

Deactivation of a Ni-Based Reforming Catalyst During the Upgrading of the Producer Gas, from Simulated to Real Conditions

The deactivation of a nickel reforming catalyst during the upgrading of the producer gas obtained by gasification of lignocellulosic biomass was studied. The research involved several steps: the selective deactivation of the catalyst in a laboratory scale; the streaming of the catalyst with the producer gas of a downdraft and an oxygen/steam circulating fluidized bed (CFB) gasifier; and tests in a reformer placed in a slipstream of the CFB gasifier. The information obtained allowed to elucidate the catalyst deactivation mechanisms taking place during the reforming of the producer gas: physical deactivation by deposition of fine ashes, aerosol particulate or carbon; poisoning by H₂S and HCl present in the gas phase and thermal sintering because of the high operation temperatures required to avoid the chemical deactivation. These physical and chemical effects depended on the composition of the biomass fuel.     

An Easy Entry to Optically Active Spiroindolinones: Chiral Brønsted Acid‐Catalysed Pictet–Spengler Reactions of Isatins

The first catalytic asymmetric Pictet–Spengler reaction of isatins is presented. BINOL‐derived phosphoric acids were found to be competent catalysts for this transformation, giving challenging spirooxindole structures bearing a quaternary stereocentre with generally good results. The 1,2,3,4‐tetrahydro‐β‐carboline products (spiroindolinones) are the core of some newly discovered anti‐malarial agents.     

Two‐dimensional fluorescence as a fingerprinting tool for monitoring wastewater treatment systems

BACKGROUND: The use of two‐dimensional (2D) fluorescence for monitoring complex biological systems requires careful assessment of the effect of chemical species present, which may be fluorescent and/or may interfere with the fluorescence response of target fluorophores. Given the complexity of fluorescence data (excitation emission matrices—EEMs), the challenge is how to recover the information embedded into those EEMs that can be related quantitatively with the observed performance of the biological processes under study. RESULTS: This work shows clearly that interference effects (such as quenching and inner filter effects) occur due to the presence of multiple species in complex biological media, such as natural water matrices, wastewaters and activated sludge. A statistical multivariate analysis is proposed to recover quantitative information from 2D fluorescence data, correlating EEMs with the observed performance. A selected case study is discussed, where 2D fluorescence spectra obtained from the effluent of a membrane bioreactor were compressed using PARAFAC and successfully correlated with the effluent chemical oxygen demand, using projection to latent structures modelling. CONCLUSION: This study demonstrates the potential of using 2D fluorescence spectroscopy as a status fingerprint. Additionally, it is shown how statistical multivariate data analysis can be used to correlate EEMs with selected performance parameters for monitoring of biological systems. Copyright © 2011 Society of Chemical Industry     

Anti-fingerprints fluorinated coating for anodized titanium avoiding color alteration

In this study amorphous fluorinated coatings applied to anodized titanium surface have been investigated. A copolymer between tetrafluoroethylene and perfluoro-4-trifluoromethoxy-1,3-dioxole (AD60) and two perfluoropolyether containing ammonium phosphate (F10) or triethoxysilane (S10) functionalities have been tested. To estimate the color alteration of the anodized titanium surfaces due to the application of the coatings, spectrophotometric analyses have been made. Water and n-dodecane contact angles as well as apparent surface energy have been evaluated. Ellipsometry and atomic force microscopy data have been used to measure the thickness of the fluorinated coatings. A tailored mechanical preliminary test has also been explored to evaluate the adhesion of the coatings on the anodized titanium surface. The resistance to surface soiling with castor oil was also preliminarily investigated. The fluorinated coating tested on anodized titanium showed a low apparent surface energy and high chromatic aspect conservation, this is particularly evident for the titanium anodized coated with triethoxysilane functionalities fluoropolymers S10.     

Dendrimer finishing influence on CO/PES blended fabrics color assessment

Textile finishing includes all processes that help to maintain the value or increase the value of the textile material. It encompasses dyeing, printing, and all the finishing treatments to realize durable press, soil release, flame retardant, antistatic, antimicrobial, or water/oil repellency properties. When these properties are realized on dyed textile fabric, one effect could be ascribed to the color change induced by finishing operations. This research focuses on the assessment of color alterations occurring on the dyed cotton/polyester blended fabrics due to the nanoparticle‐sized dendrimer (DWR), dendrimer–fluorocarbon (DWOR), and fluorocarbon (FWOR) finishing onto their surfaces. The dependence of color on the surface state of treated textiles is calculated in the context of spectrophotometric measurements. Modification of the surface roughness by reflectance spectrum and the absorbance of finishes in visible range were investigated to determine color changes between the original (control fabric, dyed but not treated) and treated fabrics. As a result of color matching calculated by CIE‐Lab values, color change is related to the surface roughness associated with absorbance values of applied finishes. In addition, fabrics mechanical properties were evaluated to estimate if finishing agents application gives rise to other changes, besides color alterations. The fabrics mechanical properties have been found not significantly altered by the aforementioned finishing treatments. These results could be applied for industrial needs (quality control), or in the artistic field of conservation, or restoration (to follow the color of paintings). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Biodiesel production from Stichococcus strains at laboratory scale

BACKGROUND: This paper reports the results of an experimental campaign of autotrophic cultures of Stichococcus strains aiming at selecting the most promising strain for biofuel production. The strain selected—S. bacillaris 158/11—was cultivated in 1 L lab‐scale bubble column photobioreactors under fed‐batch and semi‐continuous conditions. A Bold basal medium supplemented with NaNO₃ as nitrogen source was adopted. Tests were carried out at 23 °C, 140 µE m^?2 s^?1, and air flow rate ranging between 0.4 and 4 vvm. Cultures were characterized in terms of pH, concentration of total nitrogen, total organic carbon, total inorganic carbon, biomass, lipid fraction and methyl‐ester distribution of transesterified lipids. RESULTS: S. bacillaris 158/11 proved to be the best strain to produce biodiesel. Methyl‐ester distribution was characterized by a large fraction of methyl palmitate, methyl linolenate, methyl linoleate, and methyl oleate along with phytol. The process photosynthetic efficiency—fraction of available light stored as chemical energy ‐ was about 1.5%. Specific biomass productivity was ～60 mg_DM L^?1 day^?1 under the semi‐continuous conditions tested. Total lipid productivity was 14 mg L^?1 day^?1 at a dilution rate of 0.050 L day^?1. CONCLUSION: S. bacillaris 158/11 is a potential strain for massive microalgae cultures for biofuel production. Higher biomass/total‐lipid productivity could be obtained in sunlight. Copyright © 2011 Society of Chemical Industry     

Evidence for Bulk Residual Stress Strengthening in Al2O3/SiC Nanocomposites

The fracture behavior of Al₂O₃/SiC nanocomposites has been studied as a function of the SiC volume fraction and compared to that of the pure Al₂O₃ matrix. A pronounced strengthening effect was only observed for materials with low SiC content (i.e., ≤10 vol%) although no evidence of concurrent toughening was found. Assessment of near-tip crack opening displacement (COD) could not experimentally substantiate significant occurrence of an elastic crack-bridging mechanism, in contrast with a recently proposed literature model. Quantitative fractography analysis indicated that transgranular crack propagation in Al₂O₃/SiC nanocomposites depends on the location of the SiC dispersoids within the matrix texture; the higher the fraction of transgranularly located dispersoids, the more transgranular the fracture mode. Experimental evidence of remarkably high residual stresses arising from thermal dilatation mismatch (upon cooling) between Al₂O₃ and SiC phases were obtained by fluorescence and Raman spectroscopy. A strengthening mechanism is invoked which merely arises from residual stress through strengthening of Al₂O₃ grain boundaries.