scholarly journals Biogenic Metal Oxides

Biomimetics ◽  
2020 ◽  
Vol 5 (2) ◽  
pp. 29
Author(s):  
Hipassia M. Moura ◽  
Miriam M. Unterlass

Biogenic metal oxides (MxOy) feature structures as highly functional and unique as the organisms generating them. They have caught the attention of scientists for the development of novel materials by biomimicry. In order to understand how biogenic MxOy could inspire novel technologies, we have reviewed examples of all biogenic MxOy, as well as the current state of understanding of the interactions between the inorganic MxOy and the biological matter they originate from and are connected to. In this review, we first summarize the origins of the precursors that living nature converts into MxOy. From the point-of-view of our materials chemists, we present an overview of the biogenesis of silica, iron and manganese oxides, as the only reported biogenic MxOy to date. These MxOy are found across all five kingdoms (bacteria, protoctista, fungi, plants and animals). We discuss the key molecules involved in the biosynthesis of MxOy, the functionality of the MxOy structures, and the techniques by which the biogenic MxOy can be studied. We close by outlining the biomimetic approaches inspired by biogenic MxOy materials and their challenges, and we point at promising directions for future organic-inorganic materials and their synthesis.

1995 ◽  
Vol 32 (3) ◽  
pp. 187-192 ◽  
Author(s):  
W. J. Tarutis ◽  
R. F. Unz

The primary mechanisms responsible for the removal and retention of iron, manganese, and sulfate in constructed wetlands receiving acidic mine drainage (AMD) include the formation of metal oxides and sulfides within the sediments. This study was initiated to determine the kinetics of metal ion liberation, under reducing conditions, from synthetic and naturally occurring iron and manganese oxides typically found in AMD precipitates. Rates of metal ion liberation were determined during time series incubations of an organic substrate (spent mushroom compost) to which five metal oxides of varying crystallinity (amorphous and crystalline oxides of iron and manganese; natural AMD oxide) were added. All experiments were carried out in silicone-sealed polycarbonate centrifuge tubes incubated at 22°C for a period of 3, 7, 10, 14, 21 or 28 days. Tubes were sacrificed after each incubation period and were analyzed for redox potential, pH, sulfide, and metals. All tubes exhibited reducing potentials within 3 days coupled with rapidly increasing concentrations of iron and manganese. Liberation of iron and manganese decreased with increasing mineral crystallinity (amorphous > natural AMD ≫ crystalline). The results suggest that metal ion liberation from oxide minerals may be an important source of iron and manganese within constructed wetlands receiving AMD.


1998 ◽  
Vol 37 (04/05) ◽  
pp. 518-526 ◽  
Author(s):  
D. Sauquet ◽  
M.-C. Jaulent ◽  
E. Zapletal ◽  
M. Lavril ◽  
P. Degoulet

AbstractRapid development of community health information networks raises the issue of semantic interoperability between distributed and heterogeneous systems. Indeed, operational health information systems originate from heterogeneous teams of independent developers and have to cooperate in order to exchange data and services. A good cooperation is based on a good understanding of the messages exchanged between the systems. The main issue of semantic interoperability is to ensure that the exchange is not only possible but also meaningful. The main objective of this paper is to analyze semantic interoperability from a software engineering point of view. It describes the principles for the design of a semantic mediator (SM) in the framework of a distributed object manager (DOM). The mediator is itself a component that should allow the exchange of messages independently of languages and platforms. The functional architecture of such a SM is detailed. These principles have been partly applied in the context of the HEllOS object-oriented software engineering environment. The resulting service components are presented with their current state of achievement.


Author(s):  
Zuzana Kvetanová

The submitted study addresses the topic of the current state of the opinion journalism and its genres in the Slovak periodical press. The author draws attention to the question of classification of the opinion journalism of a rational and emotional type from the genre categorization point of view and, simultaneously, reflects on its application in the present journalistic practice. This brings a certain rate of confrontation between the defined theoretical premises and their subsequent practical (non-)implementation. The main objective of the study is to clarify the presence of genres of analytical and literary opinion journalism stated by media theory in the environment of the Slovak periodicals. Presentation of the basic terminological axis and the related explication of journalism genres included in the opinion journalism constitute the secondary objectives of the paper. For the purposes of achieving the set objectives, the author uses methods of logical analysis of text in combination with discourse analysis. Similarly, she predicts the evident presence of the phenomenon of hybridization in the Slovak journalistic practice.


2019 ◽  
pp. 37-47
Author(s):  
Yao Yueqin ◽  
Oleksiy Kozlov ◽  
Oleksandr Gerasin ◽  
Galyna Kondratenko

Analysis and formalization of the monitoring and automatic control tasks of the MR for the movement and execution of various types of technological operations on inclined and vertical ferromagnetic surfaces are obtained. Generalized structure of mobile robotic complex is shown with main subsystems consideration. Critical analysis of the current state of the problem of development of universal structures of mobile robots (MRs) for the various types of technological operations execution and elaborations of computerized systems for monitoring and control of MR movement is done. In particular, wheeled, walked and crawler type MRs with pneumatic, vacuum-propeller, magnetic and magnetically operated clamping devices to grip with vertical and ceiling surfaces are reviewed. The constructive features of the crawler MR with magnetic clamping devices capable of moving along sloping ferromagnetic surfaces are considered. The basic technical parameters of the MR are shown for the further synthesis of computerized monitoring and automatic control systems. Formalization of the tasks of monitoring and control of the MR positioning at the processing of large area ferromagnetic surfaces is considered from the point of view of control theory.


Author(s):  
Olivier Asselin

“Canadian cinema.” The term may appear self-evident but is problematic. First, one may question the value of national approaches to culture, especially here, in Quebec and Canada, where the debates over the Nation seem interminable, and especially now, in an era of globalization. Next, one may question the value of media-centered approaches to culture, especially when the successive waves of the “digital revolution” have blurred the boundaries between technologies and among artistic practices. Rather than try to survey “important” fiction films for theatres in Quebec or Canada, this essay adopts another point of view to examine the presence of cinema in Montreal museums over the past few years by focusing on three singular exhibitions. It may well be symptomatic of the current state of film in Quebec and Canada—but also, paradoxically, everywhere else—and says much about the relationship between medium and nation, the expansion of cinema beyond the movie theatre, and the internationalization of culture.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 834
Author(s):  
Anima M. Schäfer ◽  
Henriette E. Meyer zu Schwabedissen ◽  
Markus Grube

The central nervous system (CNS) is an important pharmacological target, but it is very effectively protected by the blood–brain barrier (BBB), thereby impairing the efficacy of many potential active compounds as they are unable to cross this barrier. Among others, membranous efflux transporters like P-Glycoprotein are involved in the integrity of this barrier. In addition to these, however, uptake transporters have also been found to selectively uptake certain compounds into the CNS. These transporters are localized in the BBB as well as in neurons or in the choroid plexus. Among them, from a pharmacological point of view, representatives of the organic anion transporting polypeptides (OATPs) are of particular interest, as they mediate the cellular entry of a variety of different pharmaceutical compounds. Thus, OATPs in the BBB potentially offer the possibility of CNS targeting approaches. For these purposes, a profound understanding of the expression and localization of these transporters is crucial. This review therefore summarizes the current state of knowledge of the expression and localization of OATPs in the CNS, gives an overview of their possible physiological role, and outlines their possible pharmacological relevance using selected examples.


2013 ◽  
Vol 726-731 ◽  
pp. 4464-4467
Author(s):  
Wei Wei ◽  
Xue Jin Zhou ◽  
Yun Tao Gao

Taking plateau red soil as research object, using the ultrasonic-assisted organic acid extraction the heavy metal zinc in it, and analyze the form of zinc. Results showed that the extraction rate can reach 68%, with the increase of time, the extraction effect of zinc is obviously enhanced in this method. Ultrasonic-assisted citric acid extraction soil can increase the extraction rate of exchangeable, bound to carbonates and bound to iron and manganese oxides relatively.


2021 ◽  
Vol 1 (10) ◽  
pp. 167-173
Author(s):  
Nurida Аlish Gasimova ◽  

The increase in citrus production is of particular economic importance both from the point of view of meeting the demand of the population for these products, and from the point of view of its use as an industrial raw material. The article studies and analyzes the current state of citrus cultivation in Azerbaijan, the possibilities of increasing their production; relevant suggestions and recommendations are made.


2021 ◽  
pp. 1-14
Author(s):  
Javier Blanco-Portals ◽  
Francesca Peiró ◽  
Sònia Estradé

Hierarchical density-based spatial clustering of applications with noise (HDBSCAN) and uniform manifold approximation and projection (UMAP), two new state-of-the-art algorithms for clustering analysis, and dimensionality reduction, respectively, are proposed for the segmentation of core-loss electron energy loss spectroscopy (EELS) spectrum images. The performances of UMAP and HDBSCAN are systematically compared to the other clustering analysis approaches used in EELS in the literature using a known synthetic dataset. Better results are found for these new approaches. Furthermore, UMAP and HDBSCAN are showcased in a real experimental dataset from a core–shell nanoparticle of iron and manganese oxides, as well as the triple combination nonnegative matrix factorization–UMAP–HDBSCAN. The results obtained indicate how the complementary use of different combinations may be beneficial in a real-case scenario to attain a complete picture, as different algorithms highlight different aspects of the dataset studied.


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