Old Father Hudson: The Three Stages of Environmental Activism in the Hudson River Valley

Consequences of development have threatened the health of the Hudson River for decades. These have included the prospect of destroying scenic value of the Hudson River Valley with the a hydroelectric power plant on Storm King Mountain, as well as the pollution of the river itself by a variety of industrial sources. Since the 1960s, a long lineage of environmental activism in the Hudson River Valley has emerged to address those issues. The example of the Hudson River supplies an excellent case study of how environmental issues began to be addressed in the later half of the 20th century. I will demonstrate how environmental activism regarding the Hudson River had developed since the 1960s. Research focused primarily on several key environmental organizations —Scenic Hudson Inc., Riverkeeper, and the Hudson River Sloop Clearwater —to reveal environmental awareness of a particular time period. Data for the project was gathered from primary sources such as contemporary newspaper articles, archival sources at the Hudson River Sloop Clearwater Collection, and the Scenic Hudson Collection. As a result, it was found that environmental activism on the Hudson River very much so reflected the evolution of the greater environmental movement’s transition from scenic to ecological concerns of the Hudson River. The Storm King case marked the beginning of the transition from preservationist to ecological concerns, the Clearwater focused on the education of the ecology of the Hudson, and the Riverkeeper pursued polluters on the basis of this altered ethic. All in all resulting in making the Hudson River one of the most cared about and distinct bodies of water in the nation

An overview of the effects of thermal processing on bioactive glasses

Bioglass® 45S5 is widely used in biomedical applications due to its ability to bond to bone and even to soft tissues. The sintering ability of Bioglass® powders is a key factor from a technological point of view, since its govern the production of advanced devices, ranging from highly porous scaffolds to functionalized coatings. Unfortunately this particular glass composition is prone to crystallize at the temperature required for sintering and this may impair the bioactivity of the original glass. For these reasons, a prerequisite to tailor the fabrication of Bioglass®-derived implants is to understand the interaction between sintering, crystallization and bioactivity. In this work the structural transformations which occur during the heat treatment of Bioglass® are reviewed and a special attention is paid to the sintering and crystallization processes. Moreover the bioactivity of the final glass-ceramics is discussed and some alternative glass formulations are reported

Dall’atomismo sociale alla società ecologica. L’etica di Murray Bookchin

Riassunto - Murray Bookchin inserisce l’analisi riguardante il rapporto tra natura e società all’interno di una più ampia riflessione dai caratteri filosofici ed etici. Tematiche sociali e tematiche ecologiche si intrecciano su diversi piani con un unico intento: rintracciare le cause della crisi sociale, ancora attuale, dalla quale è scaturita la crisi ecologica, e individuare possibili soluzioni, attingendo dalla natura modelli di moralità, che costituiscano il fondamento di una "società ecologica" o, meglio, di una "ecologia sociale".Parole-chiave: Murray Bookchin; ecologia sociale; etica ambientale; etica sociale; biocentrismo.  From Social Atomism to Ecological Society. Murray Bookchin's EthicsAbstract - Murray Bookchin examines the relation between nature and society in broader philosophical and ethical terms. In his thinking social and ecological themes interact on different levels, with a single purpouse: to identify the caises of the contemporary social crisis, from which the ecological crisis has arisen, and to find possible solutions, modeling morality on nature, to lay the foudations of an "ecological society" or, better, a "social ecology".Keywords: Murray Bookchin; Social Ecology; Environmental Ethics; Social Ethics; Biocentrism

A comparative in vivo evaluation of bioactive glasses and bioactive glass-based composites for bone tissue repair

In this work a set of novel materials for bone tissue regeneration have been tested in vivo in an animal model. In fact, despite many studies have been devoted to amorphous 45S5 Bioglass®, there is lack in the literature of works aimed to study the in vivo performance of heat-treated – and thus partially crystallized – 45S5. As widely reported, crystallization limits the bioactivity of 45S5 and is the main reason that prevents a broader use of this material. Thus, in the present work, a recently developed bioactive glass (BG_Ca/Mix) is tested, since previous investigations demonstrated that BG_Ca/Mix is particularly promising by virtue of both its high bioactivity and lower tendency to crystallize with respect to 45S5. BG_Ca/Mix sintered powders and two composites, which contain BG_Ca/Mix and an increasing percentage (20 wt% or 70 wt%) of hydroxyapatite (HA), were considered. As a term of comparison, 45S5 sintered powders were also studied. The samples were implanted in rabbits' femurs and harvested after 8 weeks. The histological analysis demonstrated that BG_Ca/Mix has an osteoconductive ability slightly higher than that of 45S5 glass-ceramics, followed by that of the composites, which may represent the starting point for obtaining systems with degradation rate tailored for a given clinical application. Moreover, the 45S5 samples were locally cracked, probably because of a non-uniform dissolution in the physiological environment. On the contrary such cracks, which could lead to implant instability and unsuitable mechanical performance, were not observed in BG_Ca/Mix

Sol-gel derived bioactive glasses with low tendency to crystallize: synthesis, post-sintering bioactivity and possible application for the production of porous scaffolds.

A new sol-gel (SG) method is proposed to produce special bioactive glasses (BG_Ca family) characterized by a low tendency to devitrify. These formulations, derived from 45S5 Bioglass®, are characterized by a high content of CaO (45.6 mol%) and by a partial or complete substitution of sodium oxide with potassium oxide (total amount of alkaline oxides: 4.6 mol%), which increases the crystallization temperature up to 900°C. In this way, it is possible to produce them by SG preserving their amorphous nature, in spite of the calcination at 850°C. The sintering behavior of the obtained SG powders is thoroughly investigated and the properties of the sintered bodies are compared to those of the melt-derived (M) counterparts. Furthermore, the SG glass powders are successfully used to produce scaffolds by means of a modified replication technique based on the combined use of polyurethane sponges and polyethylene particles. Finally, in the view of a potential application for bone tissue engineering, the cytotoxicity of the produced materials is evaluated in vitro

Advanced open-celled structures from low-temperature sintering of a crystallization-resistant bioactive glass

Most materials for bone tissue engineering are in form of highly porous open-celled components (porosity > 70%) developed by means of an adequate coupling of formulations and manufacturing technologies. This paper is dedicated to porous components from BGMS10 bioactive glass, originally designed to undergo viscous flow sintering without crystallization, which is generally known to degrade the bioactivity of 45S5 bioglass. The adopted manufacturing technologies were specifically conceived to avoid any contamination and give excellent control on the microstructures by simple operations. More precisely, 'green' components were obtained by digital light processing and direct foaming of glass powders suspended in a photosensitive organic binder or in an aqueous solution, activated with an organic base, respectively. Owing to characteristic quite large sintering window of BGMS10 glass, sintering at 750 \ub0C caused the consolidation of the structures generated at room temperature, without any evidence of viscous collapse

Load bearing capability of three-units 4Y-TZP monolithic fixed dental prostheses: An innovative model for reliable testing

In this work, three-units monolithic fixed dental prostheses (FDPs) have been analysed and a novel model for reliable testing has been proposed. Such model is based on a new design of the polymeric base of the FDP, realised via additive manufacturing (AM) - a solution that conveys at the same time quick manufacturability, low cost, custom-ability, and design freedom. By means of this new model, the load-bearing capability of three-units monolithic FDPs has been thoroughly tested; in particular, three different analyses were performed: (i) analytical with a beam-like model, (ii) numerical, using non-linear three-dimensional Finite Elements (FE) models and (iii) experimental, by static bending test. The FDPs considered in this work were manufactured using a fourth-generation zirconia, namely 4Y-TZP. The findings demonstrated the undoubted advantages of the new base configuration, which minimized the effect of the base (which as a matter of fact is absent in in-vivo conditions) on the stress state of the connectors in the FDPs, and increased the repeatability and reliability of the experimental bending tests, able to determine the load bearing capability of the 4Y-TZP FDPs