383 research outputs found
Members of the PbFCI-Type Family: Possible Candidates for Room-Temperature Photochemical Hole Burning
We report on crystal growth and about physico-chemical studies on SryBa1-yFClxBr1-x (y = 0, 0.5, and 1) compounds doped with Sm. Persistent spectral hole burning at 300 K is further reported on Sr0.5Ba0.5FCl0.5Br0.5:Sm single crystals
Danger control programs cause tissue injury and remodeling.
Are there common pathways underlying the broad spectrum of tissue pathologies that develop upon injuries and from subsequent tissue remodeling? Here, we explain the pathophysiological impact of a set of evolutionary conserved danger control programs for tissue pathology. These programs date back to the survival benefits of the first multicellular organisms upon traumatic injuries by launching a series of danger control responses, i.e., 1. Haemostasis, or clotting to control bleeding; 2. Host defense, to control pathogen entry and spreading; 3. Re-epithelialisation, to recover barrier functions; and 4. Mesenchymal, to repair to regain tissue stability. Taking kidney pathology as an example, we discuss how clotting, inflammation, epithelial healing, and fibrosis/sclerosis determine the spectrum of kidney pathology, especially when they are insufficiently activated or present in an overshooting and deregulated manner. Understanding the evolutionary benefits of these response programs may refine the search for novel therapeutic targets to limit organ dysfunction in acute injuries and in progressive chronic tissue remodeling
Danger control programs cause tissue injury and remodeling.
Are there common pathways underlying the broad spectrum of tissue pathologies that develop upon injuries and from subsequent tissue remodeling? Here, we explain the pathophysiological impact of a set of evolutionary conserved danger control programs for tissue pathology. These programs date back to the survival benefits of the first multicellular organisms upon traumatic injuries by launching a series of danger control responses, i.e., 1. Haemostasis, or clotting to control bleeding; 2. Host defense, to control pathogen entry and spreading; 3. Re-epithelialisation, to recover barrier functions; and 4. Mesenchymal, to repair to regain tissue stability. Taking kidney pathology as an example, we discuss how clotting, inflammation, epithelial healing, and fibrosis/sclerosis determine the spectrum of kidney pathology, especially when they are insufficiently activated or present in an overshooting and deregulated manner. Understanding the evolutionary benefits of these response programs may refine the search for novel therapeutic targets to limit organ dysfunction in acute injuries and in progressive chronic tissue remodeling
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Pyrogenic carbon capture and storage
The growth of biomass is considered the most efficient method currently available to extract carbon dioxide from the atmosphere. However, biomass carbon is easily degraded by microorganisms releasing it in the form of greenhouse gases back to the atmosphere. If biomass is pyrolyzed, the organic carbon is converted into solid (biochar), liquid (bio-oil), and gaseous (permanent pyrogas) carbonaceous products. During the last decade, biochar has been discussed as a promising option to improve soil fertility and sequester carbon, although the carbon efficiency of the thermal conversion of biomass into biochar is in the range of 30%–50% only. So far, the liquid and gaseous pyrolysis products were mainly considered for combustion, though they can equally be processed into recalcitrant forms suitable for carbon sequestration. In this review, we show that pyrolytic carbon capture and storage (PyCCS) can aspire for carbon sequestration efficiencies of >70%, which is shown to be an important threshold to allow PyCCS to become a relevant negative emission technology. Prolonged residence times of pyrogenic carbon can be generated (a) within the terrestrial biosphere including the agricultural use of biochar; (b) within advanced bio-based materials as long as they are not oxidized (biochar, bio-oil); and (c) within suitable geological deposits (bio-oil and CO 2 from permanent pyrogas oxidation). While pathway (c) would need major carbon taxes or similar governmental incentives to become a realistic option, pathways (a) and (b) create added economic value and could at least partly be implemented without other financial incentives. Pyrolysis technology is already well established, biochar sequestration and bio-oil sequestration in soils, respectively biomaterials, do not present ecological hazards, and global scale-up appears feasible within a time frame of 10–30 years. Thus, PyCCS could evolve into a decisive tool for global carbon governance, serving climate change mitigation and the sustainable development goals simultaneously. © 2018 John Wiley & Sons Lt
Synthesis of a Bimetallic Dodecaborate LiNaB_(12)H_(12)with Outstanding Superionic Conductivity
Metal dodecaborates M_2/_nB_(12)H_(12) (n denotes the valence of
the metal M), containing icosahedral polyatomic anion
[B_(12)H_(12)]^(2−), have been attracting increasing interest as potential
energy materials, especially in the context of hydrogen
storage and superionic conductivity. M_2/_nB_(12)H_(12) are
commonly formed as dehydrogenation intermediates from
metal borohydrides M(BH_4)_n, like LiBH_4 and Mg(BH_4)_2,
which are well-known as potential high-density hydrogen
storage materials. The strong B−B bond in the icosahedral
[B_(12)H_(12)]^(2−), however, is regarded to be the key factor that
prevents the rehydrogenation of dodecaborates. In order to
elucidate the mechanism as well as to provide effective
solutions to this problem, a novel solvent-free synthesis route
of anhydrous M_2/nB_(12)H_(12) (here M means Li, Na, and K) has
been developed. Thermal stability and transformations of the
anhydrous single phase Li_2B_(12)H_(12) suggested the formation of
the high temperature polymorph of Li_2B_(12)H_(12) during the
dehydrogenation of LiBH_4, while concurrently emphasized the
importance of further investigation on the decomposition
mechanism of metal borohydrides and metal dodecaborates.
The high stability of icosahedral [B_(12)H_(12)]^(2−), on the other hand,
favors its potential application as solid electrolyte. Recently,
Na^+ conductivity of Na_2B_(12)H_(12) was reported to be 0.1 S/cm
above its order−disorder phase transition at ∼529 K, which is
comparable to that of a polycrystalline β”-Al_2O_3 (0.24 S/cm at
573 K) solid state Na-electrolyte. Mechanistic understanding
on the diffusion behavior of cation and further improvement of
ionic conductivity at a lower temperature, however, are
important in order to facilitate the practical application of
metal dodecaborates as superionic conductors
Structural and dynamic studies of Pr(BH)
Rare earth borohydrides RE (BH4)(3) are studied in the context of energy storage, lumines-cence and magnetic applications. We have investigated the structural behavior of pra-seodymium borohydride Pr ((BH4)-B-11)(3) containing B-11 isotope because of the previously reported negative thermal expansion. Differential scanning calorimetry (DSC), in-situ var-iable temperature synchrotron radiation powder X-ray diffraction (SR-PXD) and infrared studies reveal that Pr ((BH4)-B-11)(3) undergoes to a volume contraction during the phase tran-sition from alpha alpha-Pr ((BH4)-B-11)(3) to rhombohedral r-Pr ((BH4)-B-11)(3) phase upon heating to 493 K. Surprisingly, the phase transition persists upon cooling at room temperature. Vibrational analysis also shows that the stretching frequency of BH4-3; anion does not change upon heating which indicates that the B-H bond length remains constant during the structural phase transition from alpha-Pr ((BH4)-B-11)(3) to r-Pr ((BH4)-B-11)(3) phase. Additionally, the energy barrier of reorientation motion of the BH4- anion in the alpha-phase was estimated to be ca 23 kJ/mol by quasi-elastic neutron scattering (QENS) and Raman spectroscopy. (C) 2021 The Authors. Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC
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