The problem of activating N and its subsequent hydrogenation to form NH has been approached from many directions. One of these approaches involves the use of transition metal hydride complexes. Recently, transition metal hydride complexes of Ti and Ta have been shown to activate N, but without catalytic formation of NH. Here, we show that at elevated temperatures (400 °C, 5 MPa), solid-state hydride-containing Ti compounds (TiH and BaTiOH) form a nitride-hydride surface similar to those observed with titanium clusters, but continuously (∼7 days) form NH under H/N flow conditions to achieve a catalytic cycle, with activity (up to 2.8 mmol·g··h) almost comparable to conventional supported Ru catalysts such as Cs-Ru/MgO or Ru/BaTiO that we have tested. As with the homogeneous analogues, the initial presence of hydride within the catalyst is critical. A rare hydrogen-based Mars van Krevelen mechanism may be at play here. Conventional scaling rules of pure metals predict essentially no activity for Ti, making this a previously overlooked element, but our results show that by introducing hydride, the repertoire of heterogeneous catalysts can be expanded to include formerly unexamined compositions without resorting to precious metals.

produced by the Haber-Bosch process, typically using fused iron as the catalyst. However, the iron-based catalyst requires harsh reaction conditions (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25) and catalysts that work under mild conditions are therefore much needed. This may become more relevant in the future because as the needs for ammonia shift from fertilizer to energy, new plants operating under different conditions (lower pressure, alternate N 2 / H 2 ratios, etc.) may become necessary.In terms of the catalyst metal, ruthenium (Ru) is one of the most promising candidate elements for ammonia synthesis under mild conditions. Ru-based catalysts on carbon [3] and MgO [4] have also been extensively reported. Regarding support materials, over the most recent past few years, a number of new studies have focused on new catalysts incorporating metal hydride or electride in the support, such as 12CaO·7Al 2 O 3 :e − (C12A7:e − ), [5] [Ca 2 N]:e − , [6] CaH 2 , [7] Ca 2 NH, [8] Y 5 Si 3 , [9] LaScSi, [10] LiH, [11] and BaH 2 , [12] where all of these catalysts show high activities and unusual mechanisms. As related materials, we have recently examined BaTiO 2.5 H 0.5 and TiH 2 as a catalyst for NH 3 synthesis under Haber-Bosch conditions (400 °C, 5 MPa). [13] Titanium, being an early transition metal, was traditionally viewed as an inactive metal for catalytic NH 3 Ammonia is an attractive energy carrier for the hydrogen economy, given its high hydrogen density and ease of liquefaction. A titanate oxyhydride has recently been demonstrated that can catalyze ammonia synthesis without Ru or Fe metal, despite titanium being regarded as an inert element. Here, the synthesis activity of ammonia is examined when Ru, Fe, and Co particles are supported onto the oxyhydride BaTiO 2.5 H 0.5 . The activity of BaTiO 2.5 H 0.5 as support is significantly higher than BaTiO 3 . For example, the activity for Fe and Co increases by a factor of 70-400, making them more active than Ru/ MgO, one conventional Ru catalyst. In terms of mechanism, for Ru, H/D isotope studies show participation of lattice hydride in the catalytic cycle, while kinetic analysis shows reduced H 2 poisoning probably due to spillover. For Fe (and Co), the presence of hydride results in significantly lower activation energy and N 2 reaction order, likely due to strong electron donation from the oxyhydride. This metal-dependent support effect is further verified by N 2 isotopic exchange experiments. These perovskite-type oxyhydrides can be easily modified in terms of A-and B-site (A = Ba, B = Ti); the high potential for compositional variation and morphologies will expand the search for efficient catalysts for ammonia synthesis.

In synthesizing mixed anion oxides, direct syntheses have often been employed, usually involving high temperature and occasionally high pressure. Compared with these methods, here we show how the use of a titanium perovskite oxyhydride (BaTiO2.5H0.5) as a starting material enables new multistep low temperature topochemical routes to access mixed anion compounds. Similar to labile ligands in inorganic complexes, the lability of H(-) provides the necessary reactivity for syntheses, leading to reactions and products previously difficult to obtain. For example, BaTiO2.5N0.2 can be prepared with the otherwise inert N2 gas at 400-600 °C, in marked contrast with currently available oxynitride synthetic routes. F(-)/H(-) exchange can also be accomplished at 150 °C, yielding the oxyhydride-fluoride BaTi(O, H, F)3. For BaTiO2.4D0.3F0.3, we find evidence that further anionic exchange with OD(-) yields BaTiO2.4(D(-))0.26(OD(-))0.34, which implies stable coexistence of H(+) and H(-) at ambient conditions. Such an arrangement is thermodynamically unstable and would be difficult to realize otherwise. These results show that the labile nature of hydride imparts reactivity to oxide hosts, enabling it to participate in new multistep reactions and form new materials.

In order to confirm 14-3-3 sigma (sigma) protein distribution in human tissues, immunohistochemistry was performed using various paraffin-embedded human tissues. In normal human tissues, the strongest immunoreactivity for 14-3-3sigma protein was observed in squamous epithelia at various sites, followed by basal cells of the trachea, bronchus and basal or myoepithelial cells of various glands. Moderate to weak 14-3-3sigma immunoreactivity was seen in the epithelial cells of the alimentary tract, gall bladder, urinary tract and endometrium. In the lung, 14-3-3sigma immunoreactivity was also observed in hyperplastic type II alveolar cells and metaplastic squamous cells. Immunohistochemical study using non-small-cell lung cancers revealed that 14-3-3sigma immunoreactivity was stronger in squamous cell carcinomas than in adenocarcinomas. The present study revealed that 14-3-3sigma expression was exclusively present in various epithelial cells and had a tendency to be stronger in cells destined for squamous epithelium or differentiating toward squamous cells in human normal and neoplastic cells.

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