An example for kinetic control of a solid-state phase transformation, in which the system evolves... more An example for kinetic control of a solid-state phase transformation, in which the system evolves via the path with the lowest activation barrier rather than ending in the thermodynamically most favorable state, has been demonstrated. As a case study, the phase transitions of indium sesquioxide (In2O3) have been guided by theoretical calculations and followed in situ under high-pressure high-temperature conditions in multi-anvil assemblies. The corundum-type rh-In2O3 has been synthesized from stable bixbyite-type c-In2O3 in two steps: first generating orthorhombic Rh2O3-II-type o′-In2O3 which is thermodynamically stable at 8.5 GPa/850 °C and, thereafter, exploiting the preferred kinetics in the subsequent transformation to the rh-In2O3 during decompression. This synthesis strategy of rh-In2O3 was confirmed ex situ in a toroid-type high-pressure apparatus at 8 GPa and 1100 °C. The pressure–temperature phase diagrams have been constructed and the stability fields of In2O3 polymorphs a...
Congenital hypertrophy of the retinal pigment epithelium (CHRPE) can be associated with Gardner&#... more Congenital hypertrophy of the retinal pigment epithelium (CHRPE) can be associated with Gardner's syndrome (GS). During childhood multiple adenomatose polyps develop in the colon ascendens (familiar-autosomal Polyposis coli [FAP]), and always become malignant until the age of 35. The tumour-suppressive FAP-gen was identified at the long arm of chromosome 5 (5q21). Ophthalmic funduscopy is very important. Patients with more than 3 CHRPE in one eye or a bilateral CHRPE, as well as patients with a positive family history and one unilateral solid CHRPE require further gastroenterological evaluation.
Chemistry (Weinheim an der Bergstrasse, Germany), Jan 2, 2002
The crystal structures and the enthalpy-pressure phase diagram of P(3)N(5) were investigated by u... more The crystal structures and the enthalpy-pressure phase diagram of P(3)N(5) were investigated by using density functional methods. Applying both approximations to the electron exchange and correlation gives a consistent picture for the two known polymorphs, alpha-P(3)N(5) and gamma-P(3)N(5). The calculated zone-center phonon modes compare very well with the experimental results. They indicate low-frequency bending modes for two-coordinate N atoms of alpha-P(3)N(5), which are responsible for a C2/c --> C c structural modulation of alpha-P(3)N(5) at moderate pressures. alpha-P(3)N(5) transforms into gamma-P(3)N(5) at pressures of about 6 GPa. We propose gamma-P(3)N(5) transforms into a delta-P(3)N(5) with Kyanite-type structure at pressures exceeding 43 GPa. Upon quenching, this triclinic modification of P(3)N(5) is likely to distort into a more symmetric monoclinic structure.
ABSTRACT Orthorhombic o′-In2O3 (Rh2O3(II)-type, space group Pbcn, Z = 4) is synthesized in macros... more ABSTRACT Orthorhombic o′-In2O3 (Rh2O3(II)-type, space group Pbcn, Z = 4) is synthesized in macroscopic quantities (ca. 10—100 mm3) from rhombohedral corundum-type rh-In2O3 at 8—9 GPa and 600—1100 °C in multianvil and toroid cell assemblies.
Silicon nitride (Si 3 N 4 ) is used in a variety of important technological applications. The hig... more Silicon nitride (Si 3 N 4 ) is used in a variety of important technological applications. The high fracture toughness, hardness and wear resistance of Si 3 N 4 -based ceramics are exploited in cutting tools and anti-friction bearings 1 ; in electronic applications, Si 3 N 4 is used as ...
Close Window. Close Window. Thank you for choosing to subscribe to the eTOC for RETINA. Enter you... more Close Window. Close Window. Thank you for choosing to subscribe to the eTOC for RETINA. Enter your Email address: Wolters Kluwer Health may email you for journal alerts and information, but is committed to maintaining your ...
Surgical management of macular holes consists of pars plana vitrectomy, removal of the posterior ... more Surgical management of macular holes consists of pars plana vitrectomy, removal of the posterior hyaloid facia, and peeling of the epiretinal membranes (ERM). Additionally, removal of the internal limiting membrane (ILM) may enable an increase in the anatomic and functional success rates. However, recognition of fine ILM is difficult thus increasing the time that the macula is exposed to intraoperative light. Staining the ILM with indocyanine green (ICG) dye during vitrectomy facilitates recognition of the ILM and assures that all adjacent ERM are removed. Therefore, ICG-assisted ILM peeling has gained worldwide popularity among vitreoretinal surgeons. However, there are some concerns about the intravitreal ICG application. Reports in the literature described a variety of application techniques using different concentrations. The postoperative outcomes were controversial reporting heterogeneous anatomical and functional outcomes after ICG application, as well as descriptions of adverse effects related to the dye. We discuss the indications, techniques, surgical results, and complications after intravitreal ICG injection for the treatment of macular holes.
ABSTRACT Our In situ high pressure high temperature experiments in multi-anvil assemblies unambig... more ABSTRACT Our In situ high pressure high temperature experiments in multi-anvil assemblies unambiguously evidence the stability of bixbyite-type c-In2O3 at 6 GPa from room temperature to ca. 600°C. At 5.5 GPa and ca. 1100°C, c-In2O3 reacts with free carbon from the amorphous Si‐B‐C‐N capsule being reduced to metallic indium. The material recovered from the ex situ multi-anvil experiment at 6 GPa and 1100°C using the Mo capsule is inhomogeneous, thereby its phase composition depends on the specimen position from the furnace midline that in turn is characterized by the inhomogeneous temperatures. In the midpoint of the furnace, at the highest temperature point, c-In2O3 completely transforms into a corundum-type rh-In2O3 polymorph that is recovered under ambient conditions, as confirmed by X-ray powder and electron diffraction and Raman spectroscopy. Transmission electron microscopic characterization indicates the growth of single crystals of corundum-type rh-In2O3 with an average crystal size of ∼3 μm in the specimen part away from the furnace midline. The automated electron diffraction tomography analysis and X-ray powder-diffraction point out at the possible formation of orthorhombic In2O3 polymorphs.
An example for kinetic control of a solid-state phase transformation, in which the system evolves... more An example for kinetic control of a solid-state phase transformation, in which the system evolves via the path with the lowest activation barrier rather than ending in the thermodynamically most favorable state, has been demonstrated. As a case study, the phase transitions of indium sesquioxide (In2O3) have been guided by theoretical calculations and followed in situ under high-pressure high-temperature conditions in multi-anvil assemblies. The corundum-type rh-In2O3 has been synthesized from stable bixbyite-type c-In2O3 in two steps: first generating orthorhombic Rh2O3-II-type o′-In2O3 which is thermodynamically stable at 8.5 GPa/850 °C and, thereafter, exploiting the preferred kinetics in the subsequent transformation to the rh-In2O3 during decompression. This synthesis strategy of rh-In2O3 was confirmed ex situ in a toroid-type high-pressure apparatus at 8 GPa and 1100 °C. The pressure–temperature phase diagrams have been constructed and the stability fields of In2O3 polymorphs a...
Congenital hypertrophy of the retinal pigment epithelium (CHRPE) can be associated with Gardner&#... more Congenital hypertrophy of the retinal pigment epithelium (CHRPE) can be associated with Gardner's syndrome (GS). During childhood multiple adenomatose polyps develop in the colon ascendens (familiar-autosomal Polyposis coli [FAP]), and always become malignant until the age of 35. The tumour-suppressive FAP-gen was identified at the long arm of chromosome 5 (5q21). Ophthalmic funduscopy is very important. Patients with more than 3 CHRPE in one eye or a bilateral CHRPE, as well as patients with a positive family history and one unilateral solid CHRPE require further gastroenterological evaluation.
Chemistry (Weinheim an der Bergstrasse, Germany), Jan 2, 2002
The crystal structures and the enthalpy-pressure phase diagram of P(3)N(5) were investigated by u... more The crystal structures and the enthalpy-pressure phase diagram of P(3)N(5) were investigated by using density functional methods. Applying both approximations to the electron exchange and correlation gives a consistent picture for the two known polymorphs, alpha-P(3)N(5) and gamma-P(3)N(5). The calculated zone-center phonon modes compare very well with the experimental results. They indicate low-frequency bending modes for two-coordinate N atoms of alpha-P(3)N(5), which are responsible for a C2/c --> C c structural modulation of alpha-P(3)N(5) at moderate pressures. alpha-P(3)N(5) transforms into gamma-P(3)N(5) at pressures of about 6 GPa. We propose gamma-P(3)N(5) transforms into a delta-P(3)N(5) with Kyanite-type structure at pressures exceeding 43 GPa. Upon quenching, this triclinic modification of P(3)N(5) is likely to distort into a more symmetric monoclinic structure.
ABSTRACT Orthorhombic o′-In2O3 (Rh2O3(II)-type, space group Pbcn, Z = 4) is synthesized in macros... more ABSTRACT Orthorhombic o′-In2O3 (Rh2O3(II)-type, space group Pbcn, Z = 4) is synthesized in macroscopic quantities (ca. 10—100 mm3) from rhombohedral corundum-type rh-In2O3 at 8—9 GPa and 600—1100 °C in multianvil and toroid cell assemblies.
Silicon nitride (Si 3 N 4 ) is used in a variety of important technological applications. The hig... more Silicon nitride (Si 3 N 4 ) is used in a variety of important technological applications. The high fracture toughness, hardness and wear resistance of Si 3 N 4 -based ceramics are exploited in cutting tools and anti-friction bearings 1 ; in electronic applications, Si 3 N 4 is used as ...
Close Window. Close Window. Thank you for choosing to subscribe to the eTOC for RETINA. Enter you... more Close Window. Close Window. Thank you for choosing to subscribe to the eTOC for RETINA. Enter your Email address: Wolters Kluwer Health may email you for journal alerts and information, but is committed to maintaining your ...
Surgical management of macular holes consists of pars plana vitrectomy, removal of the posterior ... more Surgical management of macular holes consists of pars plana vitrectomy, removal of the posterior hyaloid facia, and peeling of the epiretinal membranes (ERM). Additionally, removal of the internal limiting membrane (ILM) may enable an increase in the anatomic and functional success rates. However, recognition of fine ILM is difficult thus increasing the time that the macula is exposed to intraoperative light. Staining the ILM with indocyanine green (ICG) dye during vitrectomy facilitates recognition of the ILM and assures that all adjacent ERM are removed. Therefore, ICG-assisted ILM peeling has gained worldwide popularity among vitreoretinal surgeons. However, there are some concerns about the intravitreal ICG application. Reports in the literature described a variety of application techniques using different concentrations. The postoperative outcomes were controversial reporting heterogeneous anatomical and functional outcomes after ICG application, as well as descriptions of adverse effects related to the dye. We discuss the indications, techniques, surgical results, and complications after intravitreal ICG injection for the treatment of macular holes.
ABSTRACT Our In situ high pressure high temperature experiments in multi-anvil assemblies unambig... more ABSTRACT Our In situ high pressure high temperature experiments in multi-anvil assemblies unambiguously evidence the stability of bixbyite-type c-In2O3 at 6 GPa from room temperature to ca. 600°C. At 5.5 GPa and ca. 1100°C, c-In2O3 reacts with free carbon from the amorphous Si‐B‐C‐N capsule being reduced to metallic indium. The material recovered from the ex situ multi-anvil experiment at 6 GPa and 1100°C using the Mo capsule is inhomogeneous, thereby its phase composition depends on the specimen position from the furnace midline that in turn is characterized by the inhomogeneous temperatures. In the midpoint of the furnace, at the highest temperature point, c-In2O3 completely transforms into a corundum-type rh-In2O3 polymorph that is recovered under ambient conditions, as confirmed by X-ray powder and electron diffraction and Raman spectroscopy. Transmission electron microscopic characterization indicates the growth of single crystals of corundum-type rh-In2O3 with an average crystal size of ∼3 μm in the specimen part away from the furnace midline. The automated electron diffraction tomography analysis and X-ray powder-diffraction point out at the possible formation of orthorhombic In2O3 polymorphs.
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