Electrochemical engineering of anodic oxygen evolution in molten oxides

Molten oxide electrolysis (MOE) is a metal extraction process that exhibits an exceptionally high productivity in comparison with other electrowinning techniques. Furthermore, MOE has the ability to generate oxygen as an environmentally benign byproduct, which is a key asset to improve metal extraction sustainability. From an electrochemical engineering standpoint, the high concentration of metal cations dissolved in the electrolyte justifies cathode current densities above 10,000 A m[superscript −2]. At the anode, the available data suggest a mechanism of oxidation of the free oxide anions which concentration in oxide melts is reported to be limited. In this context, the application of available mass-transfer correlations for the anodic oxygen evolution suggests a key role of convection induced by gas bubbles evolution

Contribution of Electricity to Materials Processing: Historical and Current Perspectives

Introduction: Most major materials extraction processes are more than 100 years old, developed at a time of limited awareness of their environmental impact and the issue of resources limitations. In this context, it is proposed to look back at materials processes progress in parallel with the history of electric power generation. This overview reveals that electricity became a key energy vector for chemical and materials processing in less than a century. The role of electricity in the production of the highest tonnage metals (i.e., aluminum and steel) proved to be crucial, leading to higher productivity and lower energy consumption for both metals. Finally, a review of the recent developments in electrolytic steel shows that new electricity- based processes are possible, offering the opportunity for a symbiosis between future carbon-free power generation and materials processing

Aqueous alteration of potassium-bearing aluminosilicate minerals: from mechanism to processing

The anticipated increase in demand for potassium fertilizers and alumina from developing nations experiencing a high-rate of population growth brings a global sustainability concern. Most of these countries do not have economically viable resources for both commodities; and the environmental footprint of existing technologies may compromise local ecosystems. Alternatives, both in terms of resources and extraction technologies, are therefore needed. Aqueous alteration of potassium-bearing aluminosilicate minerals has been proposed as an alternative to both traditional K-fertilization and alumina production. This work discusses the mechanism of aqueous alteration of aluminosilicate minerals, and the chemical processes that have been proposed to date. Although extensive studies are found in the fields of geochemistry and materials chemistry, their results have rarely been analysed and engineered to allow a proper control and design of chemical processing. The review suggests that such a multi-disciplinary approach is required to enable new technologies that both comply with green chemistry principles and are economically viable

A thermodynamic basis for the electronic properties of molten semiconductors: the role of electronic entropy

The thermodynamic origin of a relation between features of the phase diagrams and the electronic properties of molten semiconductors is provided. Leveraging a quantitative connection between electronic properties and entropy, a criterion is derived to establish whether a system will retain its semiconducting properties in the molten phase. It is shown that electronic entropy is critical to the thermodynamics of molten semiconductor systems, driving key features of phase diagrams including, for example, miscibility gaps. Keywords: entropy; electronic entropy; thermopower; molten semiconductorUnited States. Air Force Office of Scientific Research (Grant FA9550-15-1-0046

Treatment of systemic sclerosis associated ILD: Lessons from clinical trials

Systemic sclerosis–associated interstitial lung disease remains a leading cause of mortality. Despite decades of clinical trials, the treatment effects of disease modifying anti-rheumatic drugs continue to be modest and there remains a great need for therapies that attenuate and hopefully ameliorate parenchymal lung disease. In this review, we highlight the key clinical trials that have shaped the management strategies employed by the authors, providing their strength of recommendation based on level of evidence. We also review lessons learned in more recent years, suggesting a benefit in targeting patients with subclinical interstitial lung disease with high risk for progression early in the disease course, as well as the benefit seen in a large clinical trial leading to the first Food and Drug Administration–approved treatment for systemic sclerosis–associated interstitial lung disease. These lessons come in a context of heterogeneity of patient populations and response to therapy, as well as the inherent constraints of time-limited studies to detect meaningful outcomes for patients

Centerline Depletion in Direct-Chill Cast Aluminum Alloys: The Avalanche Effect and Its Consequence for Turbulent Jet Casting

Avalanche dynamics of sedimenting grains in direct-chill casting of aluminum ingots is investigated as a primary driving force for centerline segregation. An analytical model predicting the importance of avalanche events as a function of casting parameters is proposed and validated with prior art results. New experimental results investigating the transient and steady-state centerline segregation of DC casting with a turbulent jet are reported

Targeting Costimulatory Pathways in Systemic Sclerosis

Systemic sclerosis (SSc) is an autoimmune T-cell disease that is characterized by pathological fibrosis of the skin and internal organs. SSc is considered a prototype condition for studying the links between autoimmunity and fibrosis. Costimulatory pathways such as CD28/CTLA-4, ICOS-B7RP1, CD70-CD27, CD40-CD154, or OX40-OX40L play an essential role in the modulation of T-cell and inflammatory immune responses. A growing body of evidence suggests that T-cell costimulation signals might be implicated in the pathogenesis of SSc. CD28, CTLA-4, ICOS, and OX40L are overexpressed in patients with SSc, particularly in patients with cutaneous diffuse forms. In pre-clinical models of SSc, T-cell costimulation blockade with abatacept (CTLA-4-Ig) prevented and induced the regression of inflammation-driven dermal fibrosis, improved digestive involvement, prevented lung fibrosis, and attenuated pulmonary hypertension in complementary models of SSc. Likewise, potent anti-fibrotic effects were seen with the blockade of OX40L by reducing the infiltration of inflammatory cells into lesional tissues leading to decreased fibroblast activation. Concerning clinical effects, a preliminary observational study suggested some effectiveness of abatacept on inflammatory joint involvement, whereas clinical improvement of skin fibrosis was observed in a small placebo-controlled randomized trial. Currently there is one ongoing phase II clinical trial assessing the efficacy of abatacept in SSc (ASSET trial, NCT02161406). Overall, given the lack of available effective agents and the known toxic effects of immunosuppressive agents approved for use in SSc, costimulatory pathways offer the advantage of a targeted approach to costimulatory signals and potentially a better safety profile

Increased frequency of circulating Th22 in addition to Th17 and Th2 lymphocytes in systemic sclerosis: association with interstitial lung disease

International audienceABSTRACT: INTRODUCTION: T cell abnormalities have been associated with the pathogenesis of systemic sclerosis (SSc). Recently, besides T helper (Th)17 cells the Th22 subset has been identified in humans. Our purpose was to investigate the pattern of cytokines produced and chemokine-receptors expressed by peripheral blood (PB) Th cells in SSc and healthy donors (HD) focusing on cells producing interleukin (IL)-17 and IL-22 and to identify specific clinical associations. METHODS: Clinical data and peripheral blood were collected in 33 SSc individuals and 29 HD. IL-17A, IL-22, interferon gamma (IFN-gamma, IL-4 production, the chemokine receptors CCR4, CCR6, CCR10, CXCR3 expression and the CD161 Th17 cell marker were assessed by multiparametric flow cytometry in PB CD4+ T cells. Intracellular cytokine accumulation was further investigated in CD4+ T cells expanded in vitro for 7 days. RESULTS: The frequency of Th22, Th17, Th2 but not Th1 cells was significantly increased in SSc individuals compared to HD. The percentage of CD161+CD4+ T cells was increased in SSc and correlated with the percentage of IL-17A producing cells. Moreover, the expression of the skin- and lung-homing chemokine receptor CCR6 correlated with the frequency of IL-22 and IL-17A-producing cells in SSc but not in HD. Finally, SSc interstitial lung disease (ILD) was strongly associated with higher numbers of IL-22 and, to a lesser extent, IL-17A-producing cells. CONCLUSIONS: IL-22 and IL-17A-producing T cells with skin- and lung-homing capabilities are characteristically increased in SSc. These findings support the hypothesis that Th22 in addition to Th17 cells may be involved in pathological processes leading to SSc. While the association between IL-22 producing cells and ILD needs to be assessed in larger cohorts of patients, the increased frequency of Th22 cells appears to be a useful novel biomarker in SSc