Graft copolymers of lignin from straw with 1‐ethenylbenzene: Synthesis and characterization

The synthesis of copolymers between lignin from steam‐exploded straw and 1‐ethenylbenzene is described. Beforehand, lignin from steam‐exploded straw was fully characterized by using elemental analysis, ultraviolet spectroscopy, gel permeation chromatography (GPC), Fourier transform infrared (FTIR), and both ¹H and ¹³C nuclear magnetic resonance (NMR) spectroscopy. Using a previously described procedure utilizing calcium chloride and hydrogen peroxide as reagents the synthesis of the copolymers was performed. FTIR of the copolymers showed the presence of both lignin and polystyrene. GPC analysis showed the presence of a fraction with high molecular weights. These results were confirmed from both viscosity data and differential calorimetry. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 72–79, 2001     

Electrokinetic remediation of metals and organics from historically contaminated soil

The electrokinetic remediation of an historically contaminated soil is described. The soil was contaminated with a range of metals including lead, zinc, manganese, copper and arsenic, polycyclic aromatic hydrocarbons (PAHs) and benzene, toluene, ethylbenzene and xylene (BTEX). A small‐scale experiment (973.2 g dry weight soil), utilising a planar electrode configuration, investigated the potential for moving metals and organics. After 23 days treatment at a current density of 3.72 A /m⁻², 44% of calcium and 29% of manganese were removed from the soil at the cathode. Of the other contaminating metals, zinc and lead moved towards the cathode, but with no significant removal from the soil. Movement of PAHs was also observed, with a 94% reduction in concentration in the third of the soil closest to the anode after 23 days. A larger scale experiment (46.7 kg dry weight soil) utilised a hexagonal array of tubular anodes surrounding a central tubular cathode. Treatment for 112 days led to acidification of the soil to pH 2.59 closest to the anode in a direct line between the anode and cathode. Soil not directly in line between the electrodes was not acidified significantly. Movement of metal ions was observed, in line with the electrodes, with concentrations of lead and arsenic increasing to 162% and 171% of starting concentrations closest to the anode, respectively, and those of zinc, copper and manganese decreasing to 42%, 68% and 57%, respectively. At positions not directly in line with the electrodes, no significant metal movements were observed. Overall, there was no significant removal of contaminating metals from the soil. PAHs and BTEX compounds were moved by electroosmosis towards the cathode, with soil concentrations of PAHs reduced from 720 mgkg⁻¹ to 4.7 mgkg⁻¹ after 22 days. PAHS (28 mg) and benzene (9660 mg) were recovered in granular activated carbon (GAC) columns. © 2000 Society of Chemical Industry     

Tau Cleavage Contributes to Cognitive Dysfunction in Strepto-Zotocin-Induced Sporadic Alzheimer’s Disease (sAD) Mouse Model

Tau cleavage plays a crucial role in the onset and progression of Alzheimer’s Disease (AD), a widespread neurodegenerative disease whose incidence is expected to increase in the next years. While genetic and familial forms of AD (fAD) occurring early in life represent less than 1%, the sporadic and late-onset ones (sAD) are the most common, with ageing being an important risk factor. Intracerebroventricular (ICV) infusion of streptozotocin (STZ)—a compound used in the systemic induction of diabetes due to its ability to damage the pancreatic β cells and to induce insulin resistance—mimics in rodents several behavioral, molecular and histopathological hallmarks of sAD, including memory/learning disturbance, amyloid-β (Aβ) accumulation, tau hyperphosphorylation, oxidative stress and brain glucose hypometabolism. We have demonstrated that pathological truncation of tau at its N-terminal domain occurs into hippocampi from two well-established transgenic lines of fAD animal models, such as Tg2576 and 3xTg mice, and that it’s in vivo neutralization via intravenous (i.v.) administration of the cleavage-specific anti-tau 12A12 monoclonal antibody (mAb) is strongly neuroprotective. Here, we report the therapeutic efficacy of 12A12mAb in STZ-infused mice after 14 days (short-term immunization, STIR) and 21 days (long-term immunization regimen, LTIR) of i.v. delivery. A virtually complete recovery was detected after three weeks of 12A12mAb immunization in both novel object recognition test (NORT) and object place recognition task (OPRT). Consistently, three weeks of this immunization regimen relieved in hippocampi from ICV-STZ mice the AD-like up-regulation of amyloid precursor protein (APP), the tau hyperphosphorylation and neuroinflammation, likely due to modulation of the PI3K/AKT/GSK3-β axis and the AMP-activated protein kinase (AMPK) activities. Cerebral oxidative stress, mitochondrial impairment, synaptic and histological alterations occurring in STZ-infused mice were also strongly attenuated by 12A12mAb delivery. These results further strengthen the causal role of N-terminal tau cleavage in AD pathogenesis and indicate that its specific neutralization by non-invasive administration of 12A12mAb can be a therapeutic option for both fAD and sAD patients, as well as for those showing type 2 diabetes as a comorbidity.     

Thermal degradation of ethylene–carbon monoxide alternating copolymer under inert atmosphere

This work aims to understand the mechanism of the thermal degradation of the ethylene–carbon monoxide (E-CO) alternating copolymer under mild conditions. The copolymer was subjected to accelerated ageing in an oven at different temperatures below the copolymer melting point, under argon atmosphere, and in the absence of light. The properties of the aged samples were compared with the properties of the untreated copolymer. Untreated and aged samples were analysed by mass spectroscopy (MS) with the direct introduction probe (DIP) and pyrolysis (Py) techniques. The accelerated ageing experiments showed that the thermal degradation of the E-CO alternating copolymer under inert atmosphere is characterized by chain cross-linking, loss of water, and changes in the UV absorption spectrum. The IR spectrum shows modifications only for highly degraded samples in which O−H and C=C groups are present. The experiments performed with the DIP-MS technique have confirmed that the E-CO alternating copolymer loses water during its thermal ageing. The pyrolysis products of the copolymer are linear molecules with 1,4-diketonic structure, 2-cyclopentenone derivatives, alkyl furans, and aromatic compounds. These results suggest that during the thermal degradation of the E-CO alternating copolymer under inert atmosphere, and at low temperatures, aldol condensations and/or dehydration to furan rings probably occur. © 1998 SCI.     

A proxy‐based framework to support synchronous cooperation on the Web

Owing to its widespread diffusion and ease of use, the Web is an attractive platform to support distributed cooperative work. The paper presents an object‐oriented proxy‐based framework to support synchronous cooperation on the Web. The framework implements the general‐purpose mechanisms of a proxy server. Specific application‐dependent functionalities have to be implemented in a module to be installed in the proxy‐framework. This leads to the implementation of an extensible proxy‐framework, which facilitates the development of specific cooperative services. The paper presents and evaluates several applications enabling different cooperative Web activities, to confirm the effectiveness of our proposal in terms of reusability, usability and performance. Copyright © 1999 John Wiley & Sons, Ltd.     

Dehydroacetic acid in cheese and cheese coating,results of official control in Italy

This paper reports the occurrence of dehydroacetic acid in cheese and cheese coatings collected in Italy during Agricultural Ministry Official control. Dehydroacetic acid is an antimicrobial substance not allowed to be used in EU countries as a food additive, with unknown effects on human health. Dehydroacetic acid was measured by a validated HPLC method according to Commission Decision 2002/657/EC criteria in terms of specificity, linearity, precision and accuracy, limit of detection, and limit of quantification. The method was successfully applied to 129 samples of commercial cheese coatings and related treated cheeses collected in Italy during 2017. The overall results demonstrated that about 40% of the investigated cheese coatings contained dehydroacetic acid, ranging from 0.010% to 2.5% w/w, evidencing illicit employment of this substance. Moreover, about 25% of treated cheeses contained dehydroacetic acid, from 5 to 250 mg/Kg, proving transfer of this substance from crust to cheese.     

Perspectives on hiPSC-Derived Muscle Cells as Drug Discovery Models for Muscular Dystrophies

Muscular dystrophies are a heterogeneous group of inherited diseases characterized by the progressive degeneration and weakness of skeletal muscles, leading to disability and, often, premature death. To date, no effective therapies are available to halt or reverse the pathogenic process, and meaningful treatments are urgently needed. From this perspective, it is particularly important to establish reliable in vitro models of human muscle that allow the recapitulation of disease features as well as the screening of genetic and pharmacological therapies. We herein review and discuss advances in the development of in vitro muscle models obtained from human induced pluripotent stem cells, which appear to be capable of reproducing the lack of myofiber proteins as well as other specific pathological hallmarks, such as inflammation, fibrosis, and reduced muscle regenerative potential. In addition, these platforms have been used to assess genetic correction strategies such as gene silencing, gene transfer and genome editing with clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9), as well as to evaluate novel small molecules aimed at ameliorating muscle degeneration. Furthermore, we discuss the challenges related to in vitro drug testing and provide a critical view of potential therapeutic developments to foster the future clinical translation of preclinical muscular dystrophy studies.     

Self-locking analysis in closed kinematic chains

Self-locking analysis in closed kinematic chains is sometimes likened to kinematic singularity analysis, especially when mechanisms are characterized by more than one degree of freedom. Although in singular configurations a mechanism is obviously locked-up since joint constraint reactions and friction forces rise to infinity, this approach identifies only a condition sufficient for self-locking, while the phenomenon actually occurs in a larger domain, the size of which depends on the values of friction coefficients.The paper proposes a definition of self-locking for multi degrees of freedom mechanisms and presents an algorithm for computing the geometrical locus that corresponds to a specific self-locking configuration. This methodology is then demonstrated on a simple parallel kinematic mechanism with two degrees of freedom.     

Three-dimensional core-shell hybrid solar cells via controlled in situ materials engineering

Three-dimensional core-shell organic-inorganic hybrid solar cells with tunable properties are demonstrated via electropolymerization. Air-stable poly(3,4-ethylenedioxythiophene) (PEDOT) shells with controlled thicknesses are rapidly coated onto periodic GaAs nanopillar arrays conformally, preserving the vertical 3D structure. The properties of the organic layer can be readily tuned in situ, allowing for (1) the lowering of the highest occupied molecular orbital level (|ΔE| ～ 0.28 eV), leading to the increase of open-circuit voltage (V(OC)), and (2) an improvement in PEDOT conductivity that results in enhanced short-circuit current densities (J(SC)). The incorporation of various anionic dopants in the polymer during the coating process also enables the tailoring of the polymer/semiconductor interface transport properties. Systematic tuning of the device properties results in a J(SC) of 13.6 mA cm(-2), V(OC) of 0.63 V, peak external quantum efficiency of 58.5%, leading to a power conversion efficiencies of 4.11%.     

A new purification technique for single-walled carbon nanotubes by interaction with alkali and oxygen

In this work we present a purification technique for oxygen removal from carbon nanotubes (CNTs) at relatively low temperature monitored by X-ray Photoelectron Spectroscopy and electrical characterization (change in resistance). We dope the sample with alkali metal (Na, K and Cs), which successively bind with the residual impurities of oxygen. The removal of the so formed oxides occur by heating the sample at relatively low temperatures (500-600 degrees C) without collateral damage to CNTs mat. In particular we investigate the in situ intercalation of alkali in SWNT followed by oxygen adsorption monitored by DC resistance measurements and X-ray photo-spectroscopy (XPS), demonstrating that the alkali intercalation in the samples trigger the oxygen adsorption. A subsequent sample heating at 500 degrees C removes both oxygen and alkali. Furthermore, the amount of the oxygen removal depends upon the deposited alkali species: in effect only with Na and K we obtain a complete oxygen removal, while other alkalis probably do not intercalate properly inside the nanotube walls. We hypothesize that the atomic radius of alkali can affect the intercalation properties of them inside the CNT structure.