Calcium complexation and cluster formation as principal modes of action of polymers used as superplasticizer in cement systems

2015 ◽  
Vol 73 ◽  
pp. 42-50 ◽  
Author(s):  
Thomas Sowoidnich ◽  
Tim Rachowski ◽  
Christiane Rößler ◽  
Antje Völkel ◽  
Horst-Michael Ludwig
2013 ◽  
Vol 22 (04) ◽  
pp. 271-276 ◽  
Author(s):  
P. Farahmand ◽  
J. D. Ringe

SummaryOsteoporosis in men is increasingly recognized as an important public health problem but affected patients are still under-diagnosed and -treated. As in women the diagnostic and therapeutic strategy has to be adapted to the individual case. In the practical management it is very important to detect possible causes of secondary osteoporosis, to explain the possibilities of basic therapy counteracting individual risk factors and communicate that osteoporosis is a chronic disease and adherence to a long-term treatment is crucial. In established severe osteoporosis a careful analgesic therapy is important to avoid further bone loss related to immobility. In elderly men with increased risk of falling insufficient Vitamin D supply or impaired activation of Vitamin D due to renal insufficiency must be taken into consideration. Specific medications available today for the treatment of male osteoporosis comprise among antiresorptive drugs the bis phosphonates alendronate, risedronate and zoledronic acid. Denosumab, the first biological therapy is approved for men with androgen deprivation therapy for prostate cancer. An important advantage of this potent antiresorptive drug is the increased adherence due to the comfortable application by sixmonthly subcutaneous injections. Study results from the 2-year multi-center randomized controlled ADAMO-Study will very soon allow the use of denosumab in all types of male osteoporosis. Teriparatide, the 34 N-terminal amino acid sequence of parathyroid hormone was approved for men with osteoporosis as an anabolic agent based on proven efficacy by different studies. Among drugs with other modes of action the D-hormone pro-drug alfacalcidol can be used in men alone or in combination with the advantage of pleiotropic effects on calcium absorption, parathyroids, bone and muscle. Recently also Strontium-ranelate was approved for male patients with the limitation to exclude men with clinical relevant cardiovascular risk factors. In general the possibilities to treat male osteoporosis have considerably improved during recent years. Today there is a choice of a spectrum of drugs from mild to strong potency with different modes of action on bone turnover to design strategies for individual male patients.


2019 ◽  
Vol 30 (4) ◽  
pp. 157-163 ◽  
Author(s):  
Franck E. Dayan ◽  
Geert Haesaert ◽  
Thomas Van Leeuwen ◽  
Lindy Holden-Dye ◽  
Andrew Crossthwaite ◽  
...  
Keyword(s):  

2020 ◽  
Author(s):  
Christoph Buttersack

<p>Adsorption isotherms are an essential tool in chemical physics of surfaces. However, several approaches based on a different theoretical basis exist and for isotherms including capillary condensation existing approaches can fail. Here, a general isotherm equation is derived and applied to literature data both concerning type IV isotherms of argon and nitrogen in ordered mesoporous silica, and type II isotherms of disordered macroporous silica. The new isotherm covers the full range of partial pressure (10<sup>-6</sup> - 0.7). It relies firstly on the classical thermodynamics of cluster formation, secondly on a relationship defining the free energy during the increase of the cluster size. That equation replaces the Lennard-Jones potentials used in the classical density functional theory. The determination of surface areas is not possible by this isotherm because the cross-sectional area of a cluster is unknown. Based on the full description of type IV isotherms, most known isotherms are accessible by respective simplifications. </p>


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