Chemistry for audio heritage preservation : a review of analytical techniques for audio magnetic tapes

Vast and important cultural resources are entrusted to magnetic tape around the world, but they are susceptible to degradation, which may lead to severe replay problems. Audio magnetic tapes are complex and multicomponent devices containing organic compounds and metal systems, which can be potential catalysts for many degradative reactions in the presence of water, light, or heating. The aim of this review is to collect the literature concerning the analytical determinations and instrumental approaches that can achieve the chemical identification of the components in the tape and the degradation state. Thus, a combination of destructive (such as acetone extraction) and non-destructive techniques (such as ATR FTIR spectroscopy) have been proposed, together with SEM, ESEM, XRD and TGA analyses to assess the chemical and physical characterization of the tape with the purpose to individualize restoration treatments and optimize conditions for preservation. The impact of the studies reviewed in this paper may go beyond audio, being potentially relevant to video, data, instrumentation, and logging tapes

Adsorption of Heavy Metal Ions on Alginate-Based Magnetic Nanocomposite Adsorbent Beads

Graphene oxide and its magnetic nanoparticle-based composites are a well-known tool to remove heavy metals from wastewater. Unfortunately, one of the major issues in handling such small particles consists of their difficult removal from treated wastewater (even when their magnetic properties are exploited), due to their very small diameter. One possible way to overcome this problem is to embed them in a macroscopic biopolymer matrix, such as alginate or chitosan beads. In this way, the adsorbent becomes easier to handle and can be used to build, for example, a packed column, as in a traditional industrial adsorber. In this work, the removal performances of two different embedded magnetic nanocomposite adsorbents (MNAs) are discussed. The first type of MNA is based on ferrite magnetic nanoparticles (MNPs) generated by coprecipitation using iron(II/III) salts and ammonium hydroxide, while the second is based on a 2D material composed of MNP-decorated graphene oxide. Both MNAs were embedded in cross-linked alginate beads and used to treat artificial water contaminated with chromium(III), nickel(II), and copper(II) in different concentrations. The yield of removal and differences between MNAs and non-embedded magnetic nanomaterials are also discussed. From the results, it was found that the time to reach the adsorption equilibrium is higher when compared to that of the nanomaterials only, due to the lower surface/volume ratio of the beads, but the adsorption capacity is higher, due to the additional interaction with alginate

Novel Multifunctional Magnetic Inorganic Composites: Synthesis and Characterization

We report the preparation of a series of new magnetic inorganic composites (MICs) with tuneable magnetic and mechanical properties. In the field of power inductive components and inductive heating, they could transfer energy with high robustness and excellent performances. Moreover, they may mitigate electromagnetic interference (EMI) in the LF and MF band. The MICs have been prepared using an alkaline or acidic activation process carried out in the presence of commercial magnetic micrometric particles made of anisotropic and isotropic Sr-ferrite. Three different matrices have been prepared, varying the type of activator, slag addition, water content, and aggregates

Novel Multifunctional Magnetic Inorganic Composites: Synthesis and Characterization

We report the preparation of a series of new magnetic inorganic composites (MICs) with tuneable magnetic and mechanical properties. In the field of power inductive components and inductive heating, they could transfer energy with high robustness and excellent performances. Moreover, they may mitigate electromagnetic interference (EMI) in the LF and MF band. The MICs have been prepared using an alkaline or acidic activation process carried out in the presence of commercial magnetic micrometric particles made of anisotropic and isotropic Sr-ferrite. Three different matrices have been prepared, varying the type of activator, slag addition, water content, and aggregates

Polysaccharide hydrogels for multiscale 3D printing of pullulan scaffolds

Structurally and mechanically similar to the extracellular matrix (ECM), biomimetic hydrogels offer a number of opportunities in medical applications. However, the generation of synthetic microenvironments that simulate the effects of natural tissue niches on cell growth and differentiation requires new methods to control hydrogel feature resolution, biofunctionalization and mechanical properties. Here we show how these goals can be achieved by using a pullulan-based hydrogel, engineered in composition and server as cell-adhesive hydrogel, 3D photo-printable in dimension, ranging from the macro- to the micro-scale dimensions, and of tunable mechanical properties. For this, we used absorbers that limit light penetration, achieving 3D patterning through stereolithography with feature vertical resolution of 200 μm and with overall dimension up to several millimeters. Furthermore, we report the fabrication of 3D pullulan-modified hydrogels by two-photon lithography, with sub-millimetric dimensions and minimum feature sizes down to some microns. These materials open the possibility to produce multiscale printed scaffolds that here we demonstrate to be inert for cell adhesion, but biologically compatible and easily functionalizable with cell adhesive proteins. Under these conditions, successful cell cultures were established in 2D and 3D. Keywords: Hydrogel, Biomaterials, Polysaccharide, Pullulan, 3D printing, Two photon laser lithography, Mesenchymal stromal cell

Exploring the Antitumor Potential of Copper Complexes Based on Ester Derivatives of Bis(pyrazol-1-yl)acetate Ligands

Bis(pyrazol-1-yl)acetic acid (HC(pz)(2)COOH) and bis(3,5-dimethyl-pyrazol-1-yl)acetic acid (HC(pz(Me2))(2)COOH) were converted into the methyl ester derivatives 1 (L-OMe) and 2 (L-2OMe), respectively, and were used for the preparation of Cu(I) and Cu(II) complexes 3-10. The copper(II) complexes were prepared by the reaction of CuCl2 center dot 2H(2)O or CuBr2 with ligands 1 and 2 in methanol solution. The copper(I) complexes were prepared by the reaction of Cu[(CH3CN)(4)]PF6 and 1,3,5-triaza-7-phosphaadamantane (PTA) or triphenylphosphine with L-OMe and L-2OMe in acetonitrile solution. Synchrotron radiation-based complementary techniques (XPS, NEXAFS, and XAS) were used to investigate the electronic and molecular structures of the complexes and the local structure around copper ions in selected Cu(I) and Cu(II) coordination compounds. All Cu(I) and Cu(II) complexes showed a significant in vitro antitumor activity, proving to be more effective than the reference drug cisplatin in a panel of human cancer cell lines, and were able to overcome cisplatin resistance. Noticeably, Cu complexes appeared much more effective than cisplatin in 3D spheroid cultures. Mechanistic studies revealed that the antitumor potential did not correlate with cellular accumulation but was consistent with intracellular targeting of PDI, ER stress, and paraptotic cell death induction

Novel Correlations between Spectroscopic and Morphological Properties of Activated Carbons from Waste Coffee Grounds

Massive quantities of spent coffee grounds (SCGs) are generated by users around the world. Different processes have been proposed for SCG valorization, including pyrolytic processes to achieve carbonaceous materials. Here, we report the preparation of activated carbons through pyrolytic processes carried out under different experimental conditions and in the presence of various porosity activators. Textural and chemical characterization of the obtained carbons have been achieved through Brunauer–Emmett–Teller (BET), ESEM, 13C solid state NMR, XPS, XRD, thermogravimetric and spectroscopic determinations. The aim of the paper is to relate these data to the preparation method, evaluating the correlation between the spectroscopic data and the physical and textural properties, also in comparison with the corresponding data obtained for three commercial activated carbons used in industrial adsorption processes. Some correlations have been observed between the Raman and XPS data

Revealing Commercial Epoxy Resins’ Antimicrobial Activity: A Combined Chemical–Physical, Mechanical, and Biological Study

In our continuing search for new polymer composites with antimicrobial activity, we observed that even unmodified epoxyresins exhibit significant activity. Considering their widespread use as starting materials for the realization of multifunctional nanocomposites with excellent chemical and mechanical properties, it was deemed relevant to uncover these unexpected properties that can lead to novel applications. In fact, in places where the contact with human activities makes working surfaces susceptible to microbial contamination, thus jeopardizing the sterility of the environment, their biological activity opens the way to their successful application in minimizing healthcare associated infections. To this end, three commercial and widely used epoxy resins (DGEBA/Elan TechW 152LR, 1; EPIKOTETM Resin MGS®/EPIKURETM RIM H235, 2andMC152/EW101, 3) have been investigated to determine their antibacterial and antiviral activity. After 24 h, according to ISO 22196:2011, resins1and2showedahighantibacterialefficacy(Rvalue>6.0logreduction)against Staphylococcus aureus and Escherichia coli. Resin 2, prepared according to the ratio epoxy/hardener indicated by the supplier (sample 2a) and with 10% w/w hardener excess (sample 2b), exhibited an intriguing virucidal activity against Herpes Simplex Virus type-1 and Human Coronavirus type V-OC43 as a surrogate of SARS-CoV-

Triphenylene based metal-pyridine cages

C3-symmetric pyridine containing tris-benzyl-O-substituted hexahydroxytriphenylene derivatives were prepared and used in combination with square-planar Pd(II) and Pt(II) complexes for the self-assembly of molecular cages in solution. The formation of a trigonal bipyramid M3L2 cage was demonstrated by multinuclear NMR analyses and pseudo 2D DOSY experiments and supported by semi-empirical calculation