The skeleton as an ion exchange system: Implications for the role of acid-base imbalance in the genesis of osteoporosis

2009 ◽  
Vol 10 (10) ◽  
pp. 1431-1436 ◽  
Author(s):  
Uriel S. Barzel
1976 ◽  
Vol 64 (3) ◽  
pp. 711-725
Author(s):  
J. N. Cameron

1. Techniques for the measurement of unidirectional flux rates in fish which require no anaesthesia or surgery are described. 2. Resting values for Cl- uptake at 10 and 17 degrees C were 8–03 +/− 1–11 and 13–52 +/− 0–95 mu-equiv. 200 g-1 h-1 (+/− S.E.), respectively; and for Na+ the rates were 15–49 +/− 0–40 and 26–30 +/− 0–36, respectively. 3. Hypercapnic acidosis caused an increase in Na+ uptake, presumably through Na+/H+ (or NH+4) exchange. It is suggested that this is a compensation mechanism leading to the increase in blood buffering observed in response to hypercapnia. 4. Alkalosis was observed following acute temperature increase and was accompanied by an increase in the rate of Cl-/HCO-3 exchange and also by an increase in Na+/H+ exchange. 5. The role of these branchial ion exchange mechanisms in overall acidbase regulation is discussed.


2018 ◽  
Vol 69 (1) ◽  
pp. 38-44
Author(s):  
Nicoleta Mirela Marin ◽  
Olga Tiron ◽  
Luoana Florentina Pascu ◽  
Mihaela Costache ◽  
Mihai Nita Lazar ◽  
...  

This study investigates the synergistic effects of ion exchange and biodegradation methods to remove the Acid Blue 193 also called Gryfalan Navy Blue RL (GNB) dye from wastewater. Ion exchange studies were performed using a strongly basic anion exchange resin Amberlite IRA 400. The equilibrium was characterized by a kinetic and thermodynamic points of view, establishing that the sorption of the GNB dye was subject to the Freundlich isotherm model with R2 = 0.8710. Experimental results showed that the activated resin can removed up to 93.4% when the concentration of dye solution is 5.62�10-2 mM. The biodegradation of the GNB was induced by laccase, an enzyme isolated from white-rot fungus. It was also analyzed the role of pH and dye concentration on GNB biodegradation, so 5�10-2 mM dye had a maximum discoloration efficiency of 82.9% at pH of 4. The laccase showed a very fast and robust activity reaching in a few minutes a Km value of 2.2�10-1mM. In addition, increasing the GNB concentration up to 8�10-1 mM did not triggered a substrat inhibition effect on the laccase activity. Overall, in this study we proposed a mixt physicochemical and biological approach to enhance the GNB removal and biodegradability from the wastewaters and subsequently the environment.


2012 ◽  
Author(s):  
Jeffrey A. Rine ◽  
Edward N. Coppola ◽  
Andrea M. Davis

2021 ◽  
pp. 146470012110090
Author(s):  
Romina Wainberg

Over the last two decades, Eduardo Viveiros de Castro has developed the concept of ‘perspectival anthropology’ to think philosophically with and through Amerindian cosmology. In this article, I argue that the epistemological roundness of this concept is, in actuality, a by-product of philosophical reification of Amerindian cosmological dynamics. This reification stems from distortive abstractions of specific societal structures, which rely on the silencing of two key phenomena: the fact that the central or unmarked perspective assumed in ‘perspectivism’ is that of men, and the fact that the valorisation of men’s perspective is enabled by the exchange and accumulation of women. By unearthing this exchange system that lies behind the cyclical valuation of males’ gaze, I do not seek to denounce the role of actual women in Amerindian societies. My central aim is to demonstrate that both perspectival anthropology’s depiction of Amerindian cosmology and what Viveiros de Castro calls ‘Western objectivist epistemology’ are made possible by the erasure of women’s capacity for transcendence.


2021 ◽  
Vol 629 ◽  
pp. 119271
Author(s):  
Jiří Charvát ◽  
Petr Mazúr ◽  
Martin Paidar ◽  
Jaromír Pocedič ◽  
Jiří Vrána ◽  
...  

Author(s):  
Takashi Yamamoto ◽  
Akihito Kurimoto ◽  
Riona Sato ◽  
Shoki Katada ◽  
Hirotaka Mine ◽  
...  

Ethanol conversion by Ga2O3-ZrO2 solid solution was examined in the temperature range 573–773 K, and acetone/isobutene formation was confirmed under cofeeding of H2O vapor. The reaction pathway was empirically investigated...


Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 824
Author(s):  
Przemysław J. Jodłowski ◽  
Izabela Czekaj ◽  
Patrycja Stachurska ◽  
Łukasz Kuterasiński ◽  
Lucjan Chmielarz ◽  
...  

The objective of our study was to prepare Y-, USY- and ZSM-5-based catalysts by hydrothermal synthesis, followed by copper active-phase deposition by either conventional ion-exchange or ultrasonic irradiation. The resulting materials were characterized by XRD, BET, SEM, TEM, Raman, UV-Vis, monitoring ammonia and nitrogen oxide sorption by FT-IR and Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). XRD data confirmed the purity and structure of the Y/USY or ZSM-5 zeolites. The nitrogen and ammonia sorption results indicated that the materials were highly porous and acidic. The metallic active phase was found in the form of cations in ion-exchanged zeolites and in the form of nanoparticle metal oxides in sonochemically prepared catalysts. The latter showed full activity and high stability in the SCR deNOx reaction. The faujasite-based catalysts were fully active at 200–400 °C, whereas the ZSM-5-based catalysts reached 100% activity at 400–500 °C. Our in situ DRIFTS experiments revealed that Cu–O(NO) and Cu–NH3 were intermediates, also indicating the role of Brønsted sites in the formation of NH4NO3. Furthermore, the results from our experimental in situ spectroscopic studies were compared with DFT models. Overall, our findings suggest two possible mechanisms for the deNOx reaction, depending on the method of catalyst preparation (i.e., conventional ion-exchange vs. ultrasonic irradiation).


2021 ◽  
Vol 11 (10) ◽  
pp. 4610
Author(s):  
Simone Berneschi ◽  
Giancarlo C. Righini ◽  
Stefano Pelli

Glasses, in their different forms and compositions, have special properties that are not found in other materials. The combination of transparency and hardness at room temperature, combined with a suitable mechanical strength and excellent chemical durability, makes this material indispensable for many applications in different technological fields (as, for instance, the optical fibres which constitute the physical carrier for high-speed communication networks as well as the transducer for a wide range of high-performance sensors). For its part, ion-exchange from molten salts is a well-established, low-cost technology capable of modifying the chemical-physical properties of glass. The synergy between ion-exchange and glass has always been a happy marriage, from its ancient historical background for the realisation of wonderful artefacts, to the discovery of novel and fascinating solutions for modern technology (e.g., integrated optics). Getting inspiration from some hot topics related to the application context of this technique, the goal of this critical review is to show how ion-exchange in glass, far from being an obsolete process, can still have an important impact in everyday life, both at a merely commercial level as well as at that of frontier research.


2018 ◽  
Vol 62 (1-4) ◽  
pp. 100-107 ◽  
Author(s):  
Peter N. R. Vennestrøm ◽  
Lars F. Lundegaard ◽  
Christoffer Tyrsted ◽  
Dmitriy A. Bokarev ◽  
Alina I. Mytareva ◽  
...  
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