The Effects of Additives on the Dehydrogenation of Amorphous Manganese Borohydride and Its Crystalline Form after Solvent Filtration/Extraction

A non-stoichiometric, amorphous a-Mn(BH4)(2x) hydride, accompanied by a NaCl-type salt, was mechanochemically synthesized from the additive-free mixture of (2NaBH4 + MnCl2), as well as from the mixtures containing the additives of ultrafine filamentary carbonyl nickel (Ni), graphene, and LiNH2. It is shown that both graphene and LiNH2 suppressed the release of B2H6 during thermal gas desorption, with the LiNH2 additive being the most effective suppressor of B2H6. During solvent filtration and extraction of additive-free, as well as additive-bearing, (Ni and graphene) samples from diethyl ether (Et2O), the amorphous a-Mn(BH4)(2x) hydride transformed into a crystalline c-Mn(BH4)2 hydride, exhibiting a microstructure containing nanosized crystallites (grains). In contrast, the LiNH2 additive most likely suppressed the formation of a crystalline c-Mn(BH4)2 hydride during solvent filtration/extraction. In a differential scanning calorimeter (DSC), the thermal decomposition peaks of both amorphous a-Mn(BH4)(2x) and crystalline c-Mn(BH4)2 were endothermic for the additive-free samples, as well as the samples with added graphene and Ni. The samples with LiNH2 exhibited an exothermic DSC decomposition peak.Natural Sciences and Engineering Research Council (NSERC) of Canada Discovery gran

Mechano-chemical synthesis of nanostructured hydride composites based on Li-Al-N-Mg for solid state hydrogen storage

It is observed that large quantities of hydrogen (H2) are released at ambient temperatures during the mechano-chemical synthesis of the Li-Al-N-Mg-based hydride composites using an energetic ball milling in a unique magneto-mill. For the (nLiAlH4+LiNH2; n=1, 3, 11.5, 30) composite, at the molar ratio n=1, the LiNH2 constituent destabilizes LiAlH4 and enhances its decomposition to Li3AlH6, Al and H2, and subsequently Li3AlH6 to LiH, Al and H2. LiNH2 ceases to destabilize LiAlH4 in the composites with increasing molar content of LiAlH4 (n≥3). For the (nLiAlH4+MnCl2; n=1, 3, 8, 13, 30, 63) composite, XRD phase analysis shows that chemical reaction occurs during ball milling between the hydride and chloride constituent forming either an inverse cubic spinel Li2MnCl4 for n=1 or lithium salt (LiCl) for n>1. Both reactions release hydrogen. For the (LiNH2+nMgH2; n=1, 1.5) composite the pathway of hydride reactions depends on the milling energy and milling time. Under low milling energy up to 25h there is either no reaction (1h) or the reaction products are amorphous Mg(NH2)2 (magnesium amide) and nanocrystalline LiH (lithium hydride) without any release of hydrogen. Under high milling energy a new hydride MgNH (magnesium imide) is formed due to reaction between Mg(NH2)2 and MgH2 which is always associated with the release of H2

Directed precipitation of anhydrous magnesite for improved performance of mineral carbonation of CO2

The final publication is available at Elsevier via http://dx.doi.org/10.1016/j.jece.2017.06.048 © 2017. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/This paper studies the indirect aqueous carbon sequestration via Mg(OH)2 using directed precipitation technique. This technique produces anhydrous MgCO3 (magnesite), the most desirable carbonated phase for sequestration. The formation of magnesite is significantly affected by its kinetics of precipitation in an aqueous carbonation medium. This study considers directed precipitation strategy to control precipitation of anhydrous magnesite through enhancement of the heterogeneous precipitation. Heterogeneous precipitation is implemented using seeding material that could improve the conversion efficiency of the directed carbonation of Mg(OH)2. A ternary phase diagram is achieved which represents the relative concentration of possible precipitated phases: brucite (Mg(OH)2), magnesite and hydromagnesit (Mg5(CO3)4(OH)2·4H2O). The results reveal the fundamental role of heterogeneous precipitation on the magnesite concentration and conversion percentage of Mg(OH)2 wet carbonation process. Two seeding materials, hydrophobic activated carbon and hydrophilic alumina, were tested and the influence of the surface chemistry of varying seeding sites (hydrophobic vs. hydrophilic seeds) was elaborated. At the carbonation temperature of 100°C and 150°C, a heterogeneous precipitation using hydrophilic alumina results in lower concentrations of anhydrous magnesite in precipitated compounds, even as compared to the seedless solution, owing to the hydrophilic properties of alumina. In contrast, use of activated carbon as heterogeneous nucleation sites in an aqueous medium results in a magnesite concentration of around 60% and the corresponding carbonation conversion of about 72% under the controlled condition of 200°C and 30bar CO2 pressure.Network of Centres of Excellence - Carbon Management Canada (CMC)Natural Sciences and Engineering Research Council of Canada (NSERC)Waterloo Institute for Nanotechnology (WIN

The effects of filamentary Ni, graphene and lithium amide (LiNH2) additives on the dehydrogenation behavior of mechano-chemically synthesized crystalline manganese borohydride (Mn(BH4)2) and its solvent filtration/extraction

The final publication is available at Elsevier via http:/dx.doi.org/10.1016/j.materresbull.2017.12.051 © 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/Dehydrogenation properties of mechano-chemically synthesized crystalline Mn(BH4)2 hydride without and with ultrafine filamentary carbonyl nickel (Ni), graphene and LiNH2 were investigated. It is reported for the first time that all additives suppressed the release of B2H6 with the filamentary Ni additive being the most effective suppressor of B2H6. In DSC, the decomposition peak of Mn(BH4)2 was endothermic. The estimated apparent activation energy for isothermal dehydrogenation was dramatically reduced to 44.9 ± 4.3 kJ/mol for the 5 wt.% LiNH2 additive from about 76–81 kJ/mol range for the additive-free sample and 5 wt.% filamentary Ni and graphene additives. The most striking finding, that has never been reported in the literature, is that the process of solvent filtration and extraction of the mechano-chemically synthesized (Mn(BH4)2/LiCl) sample, resulted in the crystallization of a dimetallic borohydride solvate [{Li(Et2O)2}Mn2(BH4)5] instead of crystalline Mn(BH4)2. Its dehydrogenation behavior was investigated isothermally and by TGA/DSC.Natural Sciences and Engineering Research Council (NSERC) of Canada Discovery gran

Interleukin-4 Alters Early Phagosome Phenotype by Modulating Class I PI3K Dependent Lipid Remodeling and Protein Recruitment

Phagocytosis is a complex process that involves membranelipid remodeling and the attraction and retention of key effector proteins. Phagosome phenotype depends on the type of receptor engaged and can be influenced by extracellular signals. Interleukin 4 (IL-4) is a cytokine that induces the alternative activation of macrophages (MΦs) upon prolonged exposure, triggering a different cell phenotype that has an altered phagocytic capacity. In contrast, the direct effects of IL-4 during phagocytosis remain unknown. Here, we investigate the impact of short-term IL-4 exposure (1 hour) during phagocytosis of IgG-opsonized yeast particles by MΦs. By time-lapse confocal microscopy of GFP-tagged lipid-sensing probes, we show that IL-4 increases the negative charge of the phagosomal membrane by prolonging the presence of the negatively charged second messenger PI(3,4,5)P3. Biochemical assays reveal an enhanced PI3K/Akt activity upon phagocytosis in the presence of IL-4. Blocking the specific class I PI3K after the onset of phagocytosis completely abrogates the IL-4-induced changes in lipid remodeling and concomitant membrane charge. Finally, we show that IL-4 direct signaling leads to a significantly prolonged retention profile of the signaling molecules Rac1 and Rab5 to the phagosomal membrane in a PI3K-dependent manner. This protracted early phagosome phenotype suggests an altered maturation, which is supported by the delayed phagosome acidification measured in the presence of IL-4. Our findings reveal that molecular differences in IL-4 levels, in the extracellular microenvironment, influence the coordination of lipid remodeling and protein recruitment, which determine phagosome phenotype and, eventually, fate. Endosomal and phagosomal membranes provide topological constraints to signaling molecules. Therefore, changes in the phagosome phenotype modulated by extracellular factors may represent an additional mechanism that regulates the outcome of phagocytosis and could have significant impact on the net biochemical output of a cell

Omecamtiv mecarbil in chronic heart failure with reduced ejection fraction, GALACTIC‐HF: baseline characteristics and comparison with contemporary clinical trials

Aims: The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTIC‐HF) trial. Here we describe the baseline characteristics of participants in GALACTIC‐HF and how these compare with other contemporary trials. Methods and Results: Adults with established HFrEF, New York Heart Association functional class (NYHA) ≥ II, EF ≤35%, elevated natriuretic peptides and either current hospitalization for HF or history of hospitalization/ emergency department visit for HF within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokinetic‐guided dosing: 25, 37.5 or 50 mg bid). 8256 patients [male (79%), non‐white (22%), mean age 65 years] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NT‐proBNP 1971 pg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTIC‐HF randomized patients representative of recent HF registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressure < 100 mmHg (n = 1127), estimated glomerular filtration rate < 30 mL/min/1.73 m2 (n = 528), and treated with sacubitril‐valsartan at baseline (n = 1594). Conclusions: GALACTIC‐HF enrolled a well‐treated, high‐risk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation

Nanostructured, complex hydride systems for hydrogen generation

Complex hydride systems for hydrogen (H2) generation for supplying fuel cells are being reviewed. In the first group, the hydride systems that are capable of generating H2 through a mechanical dehydrogenation phenomenon at the ambient temperature are discussed. There are few quite diverse systems in this group such as lithium alanate (LiAlH4) with the following additives: nanoiron (n-Fe), lithium amide (LiNH2) (a hydride/hydride system) and manganese chloride MnCl2 (a hydride/halide system). Another hydride/hydride system consists of lithium amide (LiNH2) and magnesium hydride (MgH2), and finally, there is a LiBH4-FeCl2 (hydride/halide) system. These hydride systems are capable of releasing from ~4 to 7 wt.% H2 at the ambient temperature during a reasonably short duration of ball milling. The second group encompasses systems that generate H2 at slightly elevated temperature (up to 100 °C). In this group lithium alanate (LiAlH4) ball milled with the nano-Fe and nano-TiN/TiC/ZrC additives is a prominent system that can relatively quickly generate up to 7 wt.% H2 at 100 °C. The other hydride is manganese borohydride (Mn(BH4)2) obtained by mechano-chemical activation synthesis (MCAS). In a ball milled (2LiBH4 + MnCl2) nanocomposite, Mn(BH4)2 co-existing with LiCl can desorb ~4.5 wt.% H2 at 100 °C within a reasonable duration of dehydrogenation. Practical application aspects of hydride systems for H2 generation/storage are also briefly discussed