•Hydrothermal carbonization was used to treat with waste PVC.•The quality of waste PVC hydrochars were resemble to bituminous coal.•Hydrochars had rich pore structure and good combustion ...characteristics.•The activation energy of hydrochars calculated by KAS methods ranged from 124.8 to 234.7 kJ/mol.
In this study, hydrothermal carbonization (HTC) was used to convert waste polyvinyl chloride to produce hydrochar by evaluating its physiochemical, structural and combustion properties for use as a solid fuel. The results showed that the yield, H/C and O/C atomic ratio of hydrochars decreased with the increase of HTC temperature, meanwhile the higher heating value increased. From physiochemical property analysis, hydrochars had more abundant pore structure and higher ordering degree of carbonaceous due to elimination, aromatization and polymerization reaction during HTC process. The combustion and kinetic analysis results show that the hydrochar obtained at the HTC temperature of 250 °C and time of 60 min had the best combustion reactivity. The activation energy calculated by KAS and OFW methods were similar, and the average activation energy of hydrochars calculated by KAS method ranged from 124.8 kJ/mol to 234.7 kJ/mol.
ClC‐6 and ClC‐7 are closely related, intracellular Cl−/H+ antiporters belonging to the CLC family of channels and transporters. They localize to acidic late endosomes and lysosomes and probably ...function in ionic homeostasis of these contiguous compartments. ClC‐7 transport function requires association with the accessory protein Ostm1, whereas ClC‐6 transport does not. To elucidate their roles in endo‐lysosomes, we measured Cl−‐ and pH‐dependences of over‐expressed wild‐type ClC‐6 and ClC‐7, as well as disease‐associated mutants, using high‐resolution recording protocols. Lowering extracellular Cl− (corresponding to luminal Cl− in endo‐lysosomes) reduced ClC‐6 currents, whereas it increased transport activity of ClC‐7/Ostm1. Low extracellular Cl− activated ClC‐7/Ostm 1 under acidic extracellular conditions, as well as under conditions of low intracellular chloride. Activation is conserved in ClC‐7Y713C, a variant displaying disrupted PI(3,5)P2 inhibition. Detailed biophysical analysis of disease‐associated ClC‐6 and ClC‐7 gain‐of‐function (GoF) variants, ClC‐6Y553C and ClC‐7Y713C, and the ClC‐7Y577C and ClC‐6Y781C correlates, identified additional functional nuances distinguishing ClC‐6 and ClC‐7. ClC‐7Y577C recapitulated GoF produced by ClC‐6Y553C. ClC‐6Y781C displayed transport activation qualitatively similar to ClC‐7Y713C, although current density did not differ from that of wild‐type ClC‐6. Finally, rClC‐7R760Q, homologous to hClC‐7R762Q, an osteopetrosis variant with fast gating kinetics, appeared indifferent to extracellular Cl−, identifying altered Cl− sensitivity as a plausible mechanism underlying disease. Collectively, the present studies underscore the distinct roles of ClC‐6 and ClC‐7 within the context of their respective localization to late endosomes and lysosomes. In particular, we suggest the atypical inhibition of ClC‐7 by luminal Cl− serves to limit excessive intraluminal Cl− accumulation.
Key points
ClC‐6 and ClC‐7 are late endosomal and lysosomal 2 Cl−/1 H+ exchangers, respectively. When targeted to the plasma membrane, both activate slowly at positive voltages.
ClC‐6 activity is decreased in low extracellular (i.e. luminal) chloride, whereas ClC‐7 is activated by low luminal chloride, even at acidic pH.
The functional gain‐of‐function phenotypes of the ClC‐6 and ClC‐7 disease mutations ClC‐6Y553C and ClC‐7Y715C are maintained when introduced in their respective homologues, ClC‐7Y577C and ClC‐6Y781C, with all mutations retaining chloride dependence of the respective wild type (WT).
An osteopetrosis mutation of ClC‐7 displaying fast gating kinetics (R762Q) was less sensitive to extracellular chloride compared to WT.
The opposing substrate dependences of ClC‐6 and ClC‐7 Cl− / H+ exchangers point to non‐overlapping physiological functions, leading us to propose that inhibition of ClC‐7 by luminal chloride and protons serves to prevent osmotic stress imposed by hyper‐accumulation of chloride.
figure legend Plasma membrane‐targeted ClC‐6 and ClC‐7 (top) produce whole cell currents characterized by opposite dependence on extracellular proton and chloride concentration. High extracellular chloride and proton concentrations (i.e. low pH) activate ClC‐6 whereas they inhibit ClC‐7. ClC‐6 localizes to late endosomes whereas ClC‐7 resides in lysosomes, and hence the physiological relevance of the extracellular conditions tested in the present studies apply to effects within the respective luminal compartments (bottom). The opposing regulation of these endolysosomal transporters by their substrates suggests non‐overlapping physiological roles. Furthermore, these findings suggest that inhibition of ClC‐7 by high luminal chloride may function to mitigate potentially disastrous osmotic effects of lysosomal chloride overload. Created with BioRender.com.
Jatropha curcas is an oilseed species that is considered an excellent alternative energy source for fossil-based fuels for growing in arid and semiarid regions, where salinity is becoming a stringent ...problem to crop production. Our working hypothesis was that nitric oxide (NO) priming enhances salt tolerance of J. curcas during early seedling development. Under NaCl stress, seedlings arising from NO-treated seeds showed lower accumulation of Na+ and Cl− than those salinized seedlings only, which was consistent with a better growth for all analyzed time points. Also, although salinity promoted a significant increase in hydrogen peroxide (H2O2) content and membrane damage, the harmful effects were less aggressive in NO-primed seedlings. The lower oxidative damage in NO-primed stressed seedlings was attributed to operation of a powerful antioxidant system, including greater glutathione (GSH) and ascorbate (AsA) contents as well as catalase (CAT) and glutathione reductase (GR) enzyme activities in both endosperm and embryo axis. Priming with NO also was found to rapidly up-regulate the JcCAT1, JcCAT2, JcGR1 and JcGR2 gene expression in embryo axis, suggesting that NO-induced salt responses include functional and transcriptional regulations. Thus, NO almost completely abolished the deleterious salinity effects on reserve mobilization and seedling growth. In conclusion, NO priming improves salt tolerance of J. curcas during seedling establishment by inducing an effective antioxidant system and limiting toxic ion and reactive oxygen species (ROS) accumulation.
Role of CFTR in epithelial physiology Saint-Criq, Vinciane; Gray, Michael A.
Cellular and molecular life sciences : CMLS,
01/2017, Letnik:
74, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Salt and fluid absorption and secretion are two processes that are fundamental to epithelial function and whole body fluid homeostasis, and as such are tightly regulated in epithelial tissues. The ...CFTR anion channel plays a major role in regulating both secretion and absorption in a diverse range of epithelial tissues, including the airways, the GI and reproductive tracts, sweat and salivary glands. It is not surprising then that defects in CFTR function are linked to disease, including life-threatening secretory diarrhoeas, such as cholera, as well as the inherited disease, cystic fibrosis (CF), one of the most common life-limiting genetic diseases in Caucasian populations. More recently, CFTR dysfunction has also been implicated in the pathogenesis of acute pancreatitis, chronic obstructive pulmonary disease (COPD), and the hyper-responsiveness in asthma, underscoring its fundamental role in whole body health and disease. CFTR regulates many mechanisms in epithelial physiology, such as maintaining epithelial surface hydration and regulating luminal pH. Indeed, recent studies have identified luminal pH as an important arbiter of epithelial barrier function and innate defence, particularly in the airways and GI tract. In this chapter, we will illustrate the different operational roles of CFTR in epithelial function by describing its characteristics in three different tissues: the airways, the pancreas, and the sweat gland.
Fabricating a robust interfacial layer on the lithium metal anode to isolate it from liquid electrolyte is vital to restrain the rapid degradation of a lithium metal battery. Here, we report that the ...solution-processed metal chloride perovskite thin film can be coated onto the lithium metal surface as a robust interfacial layer to shield the lithium metal from liquid electrolyte. Via phase analysis and density functional theory calculations, we demonstrate that the perovskite layer can allow fast lithium ion shuttle under a low energy barrier of 0.45 eV without the collapse of framework. Such perovskite modification can realize stable cycling of LiCoO
|Li cells with an areal capacity of 2.8 mAh cm
using thin lithium metal foil (50 μm) and limited electrolyte (20 μl mAh
) for over 100 cycles at 0.5 C. The metal chloride perovskite protection strategy could open a promising avenue for advanced lithium metal batteries.
Inspired by the light‐regulating capabilities of naturally occurring rhodopsin, we have constructed a visible‐light‐regulated Cl−‐transport membrane channel based on a supramolecular host–guest ...interaction. A natural retinal chromophore, capable of a visible‐light response, is used as the guest and grafted into the artificial channel. Upon introduction of an ethyl‐urea‐derived pillar6arene (Urea‐P6) host, threading or de‐threading of the retinal and selective bonding of Cl− can be utilized to regulate ion transport. Based on the visible‐light responsiveness of the host–guest interaction, Cl− transport can be regulated by visible light between ON and OFF states. Visible‐light‐regulated Cl− transport as a chemical model permits to understand comparable biological ion‐selective transport behaviors. Furthermore, this result also supplies a smart visible‐light‐responsive Cl− transporter, which may have applications in natural photoelectric conversion and photo‐controlled delivery systems.
Inspired by natural rhodopsin, a natural chromophore retinal guest with visible‐light isomerization was introduced into a solid‐state membrane channel. A novel ethyl‐urea‐derived pillar6arene (Urea‐P6) host, capable of selectively binding Cl−, was self‐assembled with the retinal guest. Based on the visible‐light‐responsiveness of the host–guest system, Cl− transport can be regulated by visible light between ON and OFF states.
A new salt, NO sub(2)BzDMAP sub(3)Cu sub(2)Cl sub(7) . H sub(2)O (1), has been synthesized, where NO sub(2)BzDMAP super(+) is 1-(4'-nitrobenzyl)-4-dimethylaminopyridinium. Herein, the synthesis, ...spectral and structural characterization, and magnetic behavior of 1 are reported. It is orthorhombic, with space group Pca2 sub(1), and a = 26.639(2) Aa, b = 9.638(1) Aa, and c = 20.011(2) Aa with V = 5137.5(7) Aa super(3) for Z = 4. The anion shows a chloride-bridged binuclear structure with Cu ... Cu distance of 3.872 Aa; the two Cu(II) ions have a tetrahedral geometry. The cations stack through p ... pi and pi ... pi interactions, and a complicated hydrogen-bonding network structure is formed through C-H ... Cl and C-H ... O hydrogen bonds. The variable temperature magnetic susceptibility measurements reveal that 1 exhibits strong antiferromagnetic interaction with J = -193.0 cm super(-1).
► A kinetic model was used to predict the radical species and their distributions. ► The generated radical species were identified by EPR. ► The second-order rate constants of sulfate radical with ...PCBs were determined.
Advanced oxidation processes (AOPs) based on sulfate radical (SO4−) have been recently used for soil and groundwater remediation. The presence of chloride ion in natural or wastewater decreases the reactivity of sulfate radical system, but explanations for this behavior were inconsistent, and the mechanisms are poorly understood. Therefore, in this paper we investigated the effect of chloride ion on the degradation of 2,4,4′-CB (PCB28) and biphenyl (BP) by persulfate, based on the produced SO4−. The results showed that the presence of chloride ion greatly inhibited the transformation of PCB28 and BP. Transformation intermediates of BP were monitored, suggesting that the chloride ion can react with SO4− to produce chlorine radical, which reacts with BP to generate chlorinated compounds. To better understand the underlying mechanisms of these processes, a kinetic model was developed for predicting the effect of chloride ion on the types of radical species and their distributions. The results showed that chloride ion could influence the selectivity of radical species and their distribution, and increase the concentration of the sum of radical species. In addition, the second-order rate constants of sulfate radical with PCBs were determined, and quantum-chemical descriptors were introduced to predict the rate constants of other PCBs based on our experimental data.
The epithelial anion transporter SLC26A9 contributes to airway surface hydration and gastric acid production. Colocalizing with CFTR, SLC26A9 has been proposed as a target for the treatment of cystic ...fibrosis. To provide molecular details of its transport mechanism, we present cryo-EM structures and a functional characterization of murine Slc26a9. These structures define the general architecture of eukaryotic SLC26 family members and reveal an unusual mode of oligomerization which relies predominantly on the cytosolic STAS domain. Our data illustrates conformational transitions of Slc26a9, supporting a rapid alternate-access mechanism which mediates uncoupled chloride transport with negligible bicarbonate or sulfate permeability. The characterization of structure-guided mutants illuminates the properties of the ion transport path, including a selective anion binding site located in the center of a mobile module within the transmembrane domain. This study thus provides a structural foundation for the understanding of the entire SLC26 family and potentially facilitates their therapeutic exploitation.
In this paper, the thermodynamic activity of two lanthanide chlorides (CeCl3 and NdCl3) in molten LiCl-KCl eutectic salt measured using open circuit potentiometry has been reported. Activity ...coefficient of CeCl3 was found to be strongly dependent on the concentration of CeCl3 in a concentration window of up to 4.66 mol % CeCl3. The activity coefficient of NdCl3 could not be measured due to the uncertainty in NdCl3/NdCl2 molar ratio in the salt, however the thermodynamic activity was measured relative to a 5 mol% Ag∣AgCl reference electrode.
The concurrent analysis of data presented in this paper along with previously published activity data for LaCl3 and GdCl3 demonstrates that the departure from ideal solution behavior shown by the rare earths chlorides correlates with ionic size of underlying rare earth element. The smaller the ionic size of the species under consideration, the greater its departure from ideal solution behavior. Further, using the activity data of all four rare earth chlorides, an ionic size dependent correlation was developed. Using this empirical correlation, it is possible to calculate the activity of all species from La(Z = 57) to Gd (Z = 64) for a concentration of up to 2.5 mol% rare earth chloride in LiCl-KCl molten salt at 773 K.
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