Water-Tolerant Superbase Polyoxometalate [H2(Nb6O19)]6- for Homogeneous Catalysis.

Here, doubly protonated Lindqvist-type niobium oxide cluster [H2(Nb6O19)]6-, fabricated by microwave-assisted hydrothermal synthesis, exhibited superbase catalysis for Knoevenagel and crossed aldol condensation reactions accompanied by activating C-H bond with pKa >26 and proton abstraction from a base indicator with pKa=26.5. Surprisingly, [H2(Nb6O19)]6- exhibited water-tolerant superbase properties for Knoevenagel and crossed aldol condensation reactions in the presence of water, although it is well known that the strong basicity of metal oxides and organic superbase is typically lost by the adsorption of water. Density functional theory calculation revealed that the basic surface oxygens that share the corner of NbO6 units in [H2(Nb6O19)]8- maintained the negative charges even after proton adsorption. This proton capacity and the presence of un-protonated basic sites led to the water tolerance of the superbase catalysis.

A New Class of Proton Conductors with Dramatically Enhanced Stability and High Conductivity for Reversible Solid Oxide Cells.

Reversible solid oxide cells based on proton conductors (P-ReSOCs) have potential to be the most efficient and low-cost option for large-scale energy storage and power generation, holding promise as an enabler for the implementation of intermittent renewable energy technologies and the widespread utilization of hydrogen. Here, the rational design of a new class of hexavalent Mo/W-doped proton-conducting electrolytes with excellent durability while maintaining high conductivity is reported. Specifically, BaMo(W)0.03 Ce0.71 Yb0.26 O3-δ exhibits dramatically enhanced chemical stability against high concentrations of steam and carbon dioxide than the state-of-the-art electrolyte materials while retaining similar ionic conductivity. In addition, P-ReSOCs based on BaW0.03 Ce0.71 Yb0.26 O3-δ demonstrate high peak power densities of 1.54, 1.03, 0.72, and 0.48 W cm-2 at 650, 600, 550, and 500 °C, respectively, in the fuel cell mode. During steam electrolysis, a high current density of 2.28 A cm-2 is achieved at a cell voltage of 1.3 V at 600 °C, and the electrolysis cell can operate stably with no noticeable degradation when exposed to high humidity of 30% H2 O at -0.5 A cm-2 and 600 °C for over 300 h. Overall, this work demonstrates the promise of donor doping for obtaining proton conductors with both high conductivity and chemical stability for P-ReSOCs.

Controlling Intermolecular Interaction and Interphase Chemistry Enabled Sustainable Water-tolerance LiMn2 O4 ||Li4 Ti5 O12 Batteries.

Solid electrolyte interphase (SEI) formation and H2 O activity reduction in Water-in-Salt electrolytes (WiSE) with an enlarged stability window of 3.0 V have provided the feasibility of the high-energy-density aqueous Li-ion batteries. Here, we extend the cathodic potential of WiSE by rationally controlling intermolecular interaction and interphase chemistry with the introduction of trimethyl phosphate (TMP) into WiSE. The TMP not merely limits the H2 O activity via the strong interaction between TMP and H2 O but also contributes to the formation of reinforced SEI involving phosphate and LiF by manipulating the Li+ solvation structure. Thus, water-tolerance LiMn2 O4 (LMO)||Li4 Ti5 O12 (LTO) full cell with a P/N ratio of 1.14 can be assembled and achieve a long cycling life of 1000 times with high coulombic efficiency of >99.9 %. This work provides a promising insight into the cost-effective practical manufacture of LMO||LTO cells without rigorous moisture-free requirements.

Nanocomposite-Decorated Filter Paper as a Twistable and Water-Tolerant Sensor for Selective Detection of 5 ppb-60 v/v% Ammonia.

Ammonia (NH3) sensors proposed for the simultaneous exhalation diagnosis, environmental pollution monitoring, and industrial leakage alarm require high flexibility, selectivity, stability, humidity tolerance, and wide-concentration-range detection; however, technical challenges still remain. Herein, twistable and water-tolerant paper-based sensors integrated over surgical masks have been developed for NH3 detection at room temperature, via decorating specially designed ternary nanocomposites (ternary-NCs) on the commercial filter paper. The NCs consist of a multiwalled carbon nanotube framework with a polypyrrole nanolayer and are further loaded with Pt nanodots. Benefiting from the synergy effect of ternary components, the ternary-NCs exhibit an ultrasensitive response to 5 ppb-60 v/v% NH3 and present high selectivity confirmed by the theory calculations. Remarkably, the filter-paper-based sensors possess outstanding stability against twisting 0-1080°, along with excellent cuttability and foldability. Critically, such paper-based sensors can be integrated over surgical masks for simulated exhaled diagnosis and display superior water tolerance even being immersed in water for 24 h. Practically, the detecting accuracy of the filter-paper-based sensor toward the simulated exhaled NH3, environmental NH3 pollution, and industrial NH3 leakage is validated using ion chromatography.

Effect of the Configuration of Copper Oxide-Ceria Catalysts in NO Reduction with CO: Superior Performance of a Copper-Ceria Solid Solution.

Various copper-ceria-based composites have attracted attention as efficient catalysts for the reduction of NO with CO. In this comparative study, we have examined the catalytic potential of different configurations of copper oxide-ceria catalysts, including catalysts based on a copper-ceria solid solution, copper oxide particles supported on ceria, and ball-milled copper oxide-ceria. The structurally different interfaces between the constituents of these catalysts afforded very different catalytic performances. The solid solution catalyst outperformed the corresponding ceria-supported and ball-milled CuO-CeO2 catalysts. The copper cations incorporated into the ceria lattice strongly improved the activity, N2 selectivity, and water vapor tolerance compared to the other catalyst configurations. The experimental observations are supported by first-principles density functional theory (DFT) studies of the reaction pathway, which indicate that the incorporation of Cu cations into the ceria matrix lowers the energy required for activating the lattice oxygen, thereby enhancing the formation and healing of oxygen vacancies, and thus promoting NO reduction with CO.

Water Tolerance After Laparoscopic Sleeve Gastrectomy.

BACKGROUND: Laparoscopic sleeve gastrectomy (LSG) is taking the lead as the most popular bariatric procedure in most regions of the world. Unlike other liquids, water is particularly affected by LSG. Because of its importance for safe hospital discharge, weight loss, and patients' lifestyle, we evaluated water tolerance after LSG. METHODS: The study included 106 consecutive patients who underwent LSG. All patients had upper gastrointestinal series (UGI) 48 h (early) and 3 months postoperatively (late), during which flow patterns (esophageal and gastric transit time) for water and juice were measured and correlated with subjective tolerance for water and juice at the same time of the contrast studies. Intraoperative measurements of the sleeve were also correlated with subjective tolerance. RESULTS: One-hundred and two (94 females, 92%) completed the 3-month follow-up. The mean age was 30.75 years; mean pre-operative BMI 46.76 kg/m2. The mean %EWL after 3 months was 32.17% ± 9.5%. Fifty patients (49%) expressed early difficulty drinking water (EDDW), and 30 (29.41%) showed late difficulty drinking water (LDDW), compared with 8 patients (7.8%) with early difficulty drinking juice (EDDJ) and 6 (5.9%) with late difficulty drinking juice (LDDJ). CONCLUSION: LSG reduces water tolerance significantly more than other liquids (juice) in the early postoperative period. Good water tolerance is a critical parameter for early hospital discharge after LSG. Larger studies with longer follow-up are warranted to determine the long-term fate of fluid tolerance following LSG and its effect on weight loss and quality of life.

Solving the Water Hypersensitive Challenge of Sulfated Solid Superacid in Acid-Catalyzed Reactions.

In the past decades, water tolerance has always been the long-pending key issue of sulfated solid superacids (SO42-/M xO y) toward industrial applications. Herein, we report a strategy for the facile coating of a thick tunable hydrophobic layer over SO42-/M xO y, which can significantly improve water tolerance, with negligible inhibition on the catalytic performance of SO42-/M xO y. Even after being directly immersed in water, the hydrophobic SO42-/M xO y can still maintain above 90% of original catalytic activity, whereas pristine SO42-/M xO y and control samples are almost completely deactivated. This strategy opens a new route to enhance the water tolerance of sulfated solid superacids.

Direct Reductive Amination of Carbonyl Compounds Catalyzed by a Moisture Tolerant Tin(IV) Lewis Acid.

Despite the ever-broadening applications of main-group 'frustrated Lewis pair' (FLP) chemistry to both new and established reactions, their typical intolerance of water, especially at elevated temperatures (>100 °C), represents a key barrier to their mainstream adoption. Herein we report that FLPs based on the Lewis acid iPr3SnOTf are moisture tolerant in the presence of moderately strong nitrogenous bases, even under high temperature regimes, allowing them to operate as simple and effective catalysts for the reductive amination of organic carbonyls, including for challenging bulky amine and carbonyl substrate partners.

Expanding the Boundaries of Water-Tolerant Frustrated Lewis Pair Hydrogenation: Enhanced Back Strain in the Lewis Acid Enables the Reductive Amination of Carbonyls.

The development of a boron/nitrogen-centered frustrated Lewis pair (FLP) with remarkably high water tolerance is presented. As systematic steric tuning of the boron-based Lewis acid (LA) component revealed, the enhanced back-strain makes water binding increasingly reversible in the presence of relatively strong base. This advance allows the limits of FLP's hydrogenation to be expanded, as demonstrated by the FLP reductive amination of carbonyls. This metal-free catalytic variant displays a notably broad chemoselectivity and generality.

Expanding Water/Base Tolerant Frustrated Lewis Pair Chemistry to Alkylamines Enables Broad Scope Reductive Aminations.

Lower Lewis acidity boranes demonstrate greater tolerance to combinations of water/strong Brønsted bases than B(C6 F5 )3 , this enables Si-H bond activation by a frustrated Lewis pair (FLP) mechanism to proceed in the presence of H2 O/alkylamines. Specifically, BPh3 has improved water tolerance in the presence of alkylamines as the Brønsted acidic adduct H2 O-BPh3 does not undergo irreversible deprotonation with aliphatic amines in contrast to H2 O-B(C6 F5 )3 . Therefore BPh3 is a catalyst for the reductive amination of aldehydes and ketones with alkylamines using silanes as reductants. A range of amines inaccessible using B(C6 F5 )3 as catalyst, were accessible by reductive amination catalysed by BPh3 via an operationally simple methodology requiring no purification of BPh3 or reagents/solvent. BPh3 has a complementary reductive amination scope to B(C6 F5 )3 with the former not an effective catalyst for the reductive amination of arylamines, while the latter is not an effective catalyst for the reductive amination of alkylamines. This disparity is due to the different pKa values of the water-borane adducts and the greater susceptibility of BPh3 species towards protodeboronation. An understanding of the deactivation processes occurring using B(C6 F5 )3 and BPh3 as reductive amination catalysts led to the identification of a third triarylborane, B(3,5-Cl2 C6 H3 )3 , that has a broader substrate scope being able to catalyse the reductive amination of both aryl and alkyl amines with carbonyls.

Facile Protocol for Water-Tolerant "Frustrated Lewis Pair"-Catalyzed Hydrogenation.

Despite rapid advances in the field of metal-free, "frustrated Lewis pair" (FLP)-catalyzed hydrogenation, the need for strictly anhydrous reaction conditions has hampered wide-scale uptake of this methodology. Herein, we report that, despite the generally perceived moisture sensitivity of FLPs, 1,4-dioxane solutions of B(C6F5)3 actually show appreciable moisture tolerance and can catalyze hydrogenation of a range of weakly basic substrates without the need for rigorously inert conditions. In particular, reactions can be performed directly in commercially available nonanhydrous solvents without subsequent drying or use of internal desiccants.

Serotonin modulates the dehydration-induced changes in tolerance for bitter water.

Drinking behavior is regulated by endogenous factors such as the hydration condition of animals and exogenous factors such as the taste of ingested fluids. These factors have been suggested to interact with each other via serotonergic (5-HT) signaling to regulate drinking behavior. In the present study, we examined how dehydration affects the intake of bitter water, which suppresses drinking behavior, via 5-HT signaling. Water deprivation increased water intake for 1h, depending on the duration of water deprivation. The intake of 1mM quinine, which is a bitter tastant, was lower than that of water in mice deprived of water for 24h but not 48 h. We next examined the involvement of the dorsal raphe nucleus (DRN) and median raphe nucleus (MRN), which contain a large population of 5-HT neurons, in changing tolerance for quinine intake after water deprivation. The intake of quinine following water deprivation for 24h, but not 48 h, increased the number of tryptophan hydroxylase-positive neurons expressing c-Fos in the DRN, but not in the MRN. Moreover, administration of paroxetine, a selective serotonin reuptake inhibitor, decreased the intake of quinine solution, but not water, in mice deprived of water for 48 h, indicating that paroxetine treatment restored the aversion to quinine. These results suggest that unresponsiveness of 5-HT neurons in the DRN may be involved in the dehydration-induced increase in tolerance for bitter water.

Impact of a short-term diazinon exposure on the osmoregulation potentiality of Caspian roach (Rutilus rutilus) fingerlings.

The stocks of Caspian roach (Rutilus rutilus), an economically important species in the Caspian Sea, are depleting. Each year millions of artificially produced fingerlings of this species are restocked in the mouth of rivers of the Southern Caspian Sea (e.g. Qare Soo River), where they are exposed to pesticides originating from regional rice and orchard fields. This early exposure to pesticides could affect the hypo-osmoregulatory ability of juvenile fish. Thus, in this study, Caspian roach fingerlings were exposed to environmentally-relevant concentrations of the organophosphate insecticide diazinon for 96 h in fresh water and then transferred to diazinon-free brackish water (BW) for another 96 h. We report that cortisol and glucose levels were significantly increased in all diazinon treatments at all sampling time points in comparison to the control group. Moreover, the thyroid hormone levels of TSH, T4, and T3 significantly decreased in diazinon-exposed fish even after the transfer to BW. The electrolytes were differentially affected during the exposure to diazinon and after the transfer to BW. The number of chloride cells in the gill tissue was significantly increased during diazinon exposure at the higher concentrations and decreased to control levels after transfer to BW. Finally, gill and kidney tissues showed many histopathological changes in diazinon-exposed fish even after 240 h in BW. These results suggest that the release of Caspian roach fingerlings into the diazinon-contaminated Caspian Sea regions may alter their physiology and jeopardize their survival, which could lead to a failure in rebuilding the Caspian roach stocks in the Caspian Sea.

Watering cattle (young bulls) with brackish water--a hazard due to its salt content?

OBJECTIVE: The aim of this experimental study was primarily to test the effects and reactions of cattle offered salty water as the only source of drinking water. MATERIAL AND METHODS: Mineral balance studies were carried out on three bull, continuously fed a ration based on hay, hay cobs, barley, soybean meal and a vitamin/mineral supplement. The salt content of the drinking water varied between the trials (trials I/II/III: 0.10/5.00/10.0 g/l; town water supplemented by different amounts of an additive containing 95.4% sodium chloride and 4.6% potassium chloride). RESULTS: Rising salt concentration of the drinking water led to significantly higher sodium, potassium and chloride intake (sodium: trial I/II/III = 5.42/59.5/ 157 g/day; potassium: trials I/II/III = 108/117/121 g/day; chloride: trials I/II/III = 22.8/112/266 g/day) mainly caused by a significantly higher water intake (trials I/II/III: 21.8 ± 2.03/30.4 ± 3.08/41.5 ± 5.89 kg/day). Amounts of urine increased significantly (trials I/II/III: 3.99 ± 0.46/ 9.66 ± 1.34/20.2 ± 3.14 kg/day). The concentrations of minerals in the urine (sodium: trials I/II/III = 123/3729/6705 mg/kg; potassium: trials I/II/III = 17345/9996/ 5496 mg/kg; chloride: trials I/II/III = 2020/ 9672/11870 mg/kg) and faeces (sodium: trials I/II/III = 1299/6544/ 7653 mg/kg; potassium: trials I/II/III = 6343/3719/3490 mg/kg; chloride: trials I/II/III = 3851/4580/4693 mg/kg) also changed significantly over time. Serum values of sodium tended to decrease (trials I/II/III: 142/137/137 mmol/l) within the physiological range, whereas those of chloride increased (trials I/II/III: 91.5/95.6/97.5 mmol/l) at higher salt concentrations in drinking water. The haematocrit, pH-value as well as urea content in blood were not affected by the higher salt intake. In balance trial III (highest salt load: 10.0 g/l), sodium intake of the bulls reached 0.57 ± 0.03 g/kg BW (~22.1 ± 0.9 g sodium/kg dry matter feed). CONCLUSION AND CLINICAL RELEVANCE: An increase of salinity in drinking water up to 10 g/l--with otherwise harmless water quality--had no measurable negative effects on animal health in the investigation period and subsequent periods (total of 58 days with more than 5.00 g of salt per litre drinking water).