High-Pressure Synthesis and Characterization of the Ammonium Yttrium Borate (NH₄)YB₈O₁₄

The first high-pressure yttrium borate (NH₄)­YB₈O₁₄ was synthesized at 12.8 GPa/1300 °C using a Walker-type multianvil module. The compound crystallizes in the orthorhombic space group <i>Pnma</i> (no. 62) with the lattice parameters <i>a</i> = 17.6375(9), <i>b</i> = 10.7160(5), and <i>c</i> = 4.2191(2) Å. (NH₄)­YB₈O₁₄ constitutes a novel structure type but exhibits similarities to the crystal structure of β-BaB₄O₇. X-ray single-crystal and powder diffraction, EDX, vibrational spectroscopy as well as quantum chemical calculations were used to characterize (NH₄)­YB₈O₁₄

The Indium Borate In₁₉B₃₄O₇₄(OH)₁₁ with T2 Supertetrahedra

The trigonal indium borate In₁₉B₃₄O₇₄(OH)₁₁ was synthesized in a Walker-type multianvil apparatus under high-pressure/high-temperature conditions of 13 GPa and 1150 °C. The crystal structure could be determined by single-crystal X-ray diffraction data collected at room temperature. In₁₉B₃₄O₇₄(OH)₁₁ crystallizes in the trigonal space group <i>R</i>3̅ (Z = 3) with the lattice parameters <i>a</i> = 1802.49(6) pm, <i>c</i> = 1340.46(5) pm, and <i>V</i> = 3.7716(3) nm³. The structure of In₁₉B₃₄O₇₄(OH)₁₁ contains alternating B–O T2 supertetrahedra units. The presence of hydroxyl groups was confirmed with vibrational spectroscopic methods such as Raman and IR. Besides H₂InB₅O₁₀, In₁₉B₃₄O₇₄(OH)₁₁ is now the second known compound in the system In–B–O–H

Synthesis and Characterization of the New Strontium Borogermanate Sr_{3–<i>x</i>/2}B_2–<i>x</i>Ge_4+<i>x</i>O₁₄ (<i>x</i> = 0.32)

The strontium borogermanate Sr_{3–<i>x</i>/2}B_2–<i>x</i>Ge_4+<i>x</i>O₁₄ (<i>x</i> = 0.32) was synthesized by high-temperature solid-state reaction of SrO, GeO₂, and H₃BO₃ in a NaF/KF flux system using platinum crucibles. The structure determination revealed that Sr_{3–<i>x</i>/2}B_2–<i>x</i>Ge_4+<i>x</i>O₁₄ (<i>x</i> = 0.32) crystallizes in the trigonal space group <i>P</i>321 (No. 150) with the parameters <i>a</i> = 800.7(2) and <i>c</i> = 488.8(2) pm, with <i>R</i>1 = 0.0281, <i>wR</i>2 = 0.0671 (all data), and <i>Z</i> = 1. The crystal structure of Sr_{3–<i>x</i>/2}B_2–<i>x</i>Ge_4+<i>x</i>O₁₄ (<i>x</i> = 0.32) consists of distorted SrO₈ cubes, GeO₆ octahedra, GeO₄ tetrahedra, and BO₄ tetrahedra. In addition to the structural investigations, Raman and IR spectroscopic investigations were carried out

Narrow-Band Red Emission in the Nitridolithoaluminate Sr₄[LiAl₁₁N₁₄]:Eu²⁺

The new narrow-band red-emitting phosphor material Sr₄[LiAl₁₁N₁₄]:Eu²⁺ was synthesized by solid-state reaction using a tungsten crucible with a cover plate in a tube furnace. When excited with blue light (460 nm), it exhibits red fluorescence with an emission maximum at 670 nm and a full width at half-maximum of 1880 cm^–1 (∼85 nm). The crystal structure was solved and refined from single-crystal X-ray diffraction data. This new compound from the group of the nitridolithoaluminates crystallizes in the orthorhombic space group <i>Pnnm</i> (No. 58) with the following unit-cell parameters: <i>a</i> = 10.4291(7) Å, <i>b</i> = 10.4309(7) Å, and <i>c</i> = 3.2349(2) Å. Sr₄[LiAl₁₁N₁₄]:Eu²⁺ shows a pronounced tetragonal pseudo-symmetry. It consists of a framework of disordered (Al/Li)­N₄ and AlN₄ tetrahedra that are connected to each other by common corners and edges. Along the [001] direction, the tetrahedral network creates empty four-membered-ring channels as well as five-membered-ring channels, in which the Sr²⁺ cations are located

Do bacteria shape our development? Crosstalk between intestinal microbiota and HPA axis

Contains fulltext : 179965.pdf (publisher's version ) (Closed access)The human body contains as many bacteria in the intestine as the total number of human body cells. These bacteria have a central position in human health and disease, and would also play a role in the regulation of emotions, behavior, and even higher cognitive functions. The Hypothalamic-Pituitary-Adrenal axis (HPA axis) is a major physiological stress system that produces cortisol. This hormone is involved in responding to environmental stress and also shapes many aspects of brain development. Both the HPA axis and the intestinal microbiota show rapid and profound developmental changes during the first years of life. Early environmental disturbances can affect the development of both systems. Early adversity, for example, is known to lead to later unbalances in both, as well as to psychopathological behavior and emotions. The goal of this theoretical review is to summarize current knowledge on the developmental crosstalk between the intestinal microbiota and the HPA axis, providing a basis for understanding the development and bidirectional communication between these two essential systems in human functioning.14 p

Effects of Gigapascal Level Pressure on Protein Structure and Function

Information on very high pressure (VHP) effects on proteins is limited and therefore effects of VHP on chemistry, structure and function of two model proteins in medical use were studied. VHP (8 GPa) application to l-asparaginase (L-ASNase) resulted in faster mobility on clear native gels. VHP induced generation of lower-MW forms of L-ASNase but VHP treatment did not deteriorate asparaginase activity. Electrophoretic patterns in native and denaturing gels were comparable for untreated and pressurized recombinant human growth hormone (rhGH). rhGH function, however, was deteriorated as shown by a bioassay. In L-ASNase and rhGH a series of protein modifications and amino acid exchanges (indicating cleavage of covalent bonds) were revealed that may probably lead to functional and conformational changes. The findings have implications in protein chemistry, structure, and function and are useful for designing biotechnological applications of protein products

Effects of Gigapascal Level Pressure on Protein Structure and Function

Information on very high pressure (VHP) effects on proteins is limited and therefore effects of VHP on chemistry, structure and function of two model proteins in medical use were studied. VHP (8 GPa) application to l-asparaginase (L-ASNase) resulted in faster mobility on clear native gels. VHP induced generation of lower-MW forms of L-ASNase but VHP treatment did not deteriorate asparaginase activity. Electrophoretic patterns in native and denaturing gels were comparable for untreated and pressurized recombinant human growth hormone (rhGH). rhGH function, however, was deteriorated as shown by a bioassay. In L-ASNase and rhGH a series of protein modifications and amino acid exchanges (indicating cleavage of covalent bonds) were revealed that may probably lead to functional and conformational changes. The findings have implications in protein chemistry, structure, and function and are useful for designing biotechnological applications of protein products

Effects of Gigapascal Level Pressure on Protein Structure and Function

Information on very high pressure (VHP) effects on proteins is limited and therefore effects of VHP on chemistry, structure and function of two model proteins in medical use were studied. VHP (8 GPa) application to l-asparaginase (L-ASNase) resulted in faster mobility on clear native gels. VHP induced generation of lower-MW forms of L-ASNase but VHP treatment did not deteriorate asparaginase activity. Electrophoretic patterns in native and denaturing gels were comparable for untreated and pressurized recombinant human growth hormone (rhGH). rhGH function, however, was deteriorated as shown by a bioassay. In L-ASNase and rhGH a series of protein modifications and amino acid exchanges (indicating cleavage of covalent bonds) were revealed that may probably lead to functional and conformational changes. The findings have implications in protein chemistry, structure, and function and are useful for designing biotechnological applications of protein products

New High-Pressure Gallium Borate Ga₂B₃O₇(OH) with Photocatalytic Activity

The new high-pressure gallium borate Ga₂B₃O₇(OH) was synthesized in a Walker-type multianvil apparatus under high-pressure/high-temperature conditions of 10.5 GPa and 700 °C. For the system Ga–B–O–H, it is only the second known compound next to Ga₉B₁₈O₃₃(OH)₁₅·H₃B₃O₆·H₃BO₃. The crystal structure of Ga₂B₃O₇(OH) was determined by single-crystal X-ray diffraction data collected at room temperature. Ga₂B₃O₇(OH) crystallizes in the orthorhombic space group <i>Cmce</i> (<i>Z</i> = 8) with the lattice parameters <i>a</i> = 1050.7(2) pm, <i>b</i> = 743.6(2) pm, <i>c</i> = 1077.3(2) pm, and <i>V</i> = 0.8417(3) nm³. Vibrational spectroscopic methods (Raman and IR) were performed to confirm the presence of the hydroxyl group. Furthermore, the band gap of Ga₂B₃O₇(OH) was estimated via quantum-mechanical density functional theory calculations. These results led to the assumption that our gallium borate could be a suitable substance to split water photocatalytically, which was tested experimentally

Structural Redetermination and Photoluminescence Properties of the Niobium Oxyphosphate (NbO)₂P₄O₁₃

The structure of (NbO)₂P₄O₁₃ was solved and refined based on new single-crystal diffraction data revealing considerably more complexity than previously described. (NbO)₂P₄O₁₃ crystallizes in the triclinic space group <i>P</i>1̅ with <i>Z</i> = 6. The lattice parameters determined at room temperature are <i>a</i> = 1066.42(4) pm, <i>b</i> = 1083.09(4) pm, <i>c</i> = 1560.46(5) pm, α = 98.55(1)°, β = 95.57(1)°, γ = 102.92(1)°, and <i>V</i> = 1.7213(2) nm³. The superstructure contains 64 unique atoms including two disordered semioccupied oxygen positions. An unusual 180° bond angle between two [P₄O₁₃]^6– groups was refined to form half-occupied, split positions in agreement with previous reports. The IR and Raman spectra reflect the appearance of overlapping bands assignable to specific group vibrations as well as P–O–P linkages present in the [P₄O₁₃]^6– entities. Investigation of the powdered product concerning its photoluminescence properties revealed an excitability in the UV at 270 nm assigned to O2p–Nb4d charge transfer transitions. A resulting broad-band emission with the maximum in the visible region at 455 nm was determined