Chemically specific termination control of oxide interfaces via layer-by-layer mean inner potential engineering.

Creating oxide interfaces with precise chemical specificity at the atomic layer level is desired for the engineering of quantum phases and electronic applications, but highly challenging, owing partially to the lack of in situ tools to monitor the chemical composition and completeness of the surface layer during growth. Here we report the in situ observation of atomic layer-by-layer inner potential variations by analysing the Kikuchi lines during epitaxial growth of strontium titanate, providing a powerful real-time technique to monitor and control the chemical composition during growth. A model combining the effects of mean inner potential and step edge density (roughness) reveals the underlying mechanism of the complex and previously not well-understood reflection high-energy electron diffraction oscillations observed in the shuttered growth of oxide films. General rules are proposed to guide the synthesis of atomically and chemically sharp oxide interfaces, opening up vast opportunities for the exploration of intriguing quantum phenomena at oxide interfaces.

Two new iridoids from roots of Patrinia scabra Bunge.

Two new iridoids 1,3-dimethyloxy-7-hydroxymethyl-4-(3-methyl-butyryloxymethyl)-1-hydrocyclopenta-4,7-diene[c]pyran-6-one (1) and 1,3-dimethyloxy-7-hydroxymethyl-4-methyloxymethyl-1-hydrocyclopenta-4,7-diene[c]pyran-6-one (2) were isolated from the roots of Patrinia scabra Bunge. The structure elucidation of the isolated compounds was based primarily on HRESIMS, EIMS, IR, UV, 1D- and 2D-NMR analyses, including COSY, HMQC, HMBC and NOESY correlations, as well as X-ray crystallographic analysis.

Optic nerve and peripapillary choroidal microvasculature of the rat eye.

PURPOSE: To investigate the three-dimensional microvascular anatomy of the optic nerve and peripapillary choroid in the rat eye. METHODS: Gross vascular anatomy of the posterior eye segment of Wistar rats was studied in serial microsections with a light microscope. The optic nerve and peripapillary choroidal vessels were sequentially microdissected, using methylmethacrylate corrosion microvascular castings, and were examined with a scanning electron microscope to determine the three-dimensional relationships of the vessels. RESULTS: The posterior ciliary artery traveled along the inferior side of the optic nerve sheath, directly entered the optic nerve head, and divided into three branches: the central retinal artery and medial and lateral long posterior ciliary arteries, which provided several short branches to the choroid. The optic nerve head vasculature was consistently nourished by a recurrent arteriole from the central retinal artery and an arteriole from the choroidal artery at the peripapillary choroid. The central retinal vein flowed into a venous anastomosis along the optic disc border of the peripapillary choroid. Capillaries within the optic nerve drained into the central retinal vein, the marginal venous anastomosis of the peripapillary choroid, and the pial veins, all of which flowed into the posterior ciliary veins along the optic nerve sheath. CONCLUSIONS: The findings illustrate vascular anatomic differences in optic nerve and peripapillary choroidal microcirculation between rat and human. In rats, the peripapillary choroid plays a significant role in both blood supply and venous drainage of the optic nerve head. The central retinal artery also contributes to the optic nerve head circulation.

Morphometric characteristics of optic disk with disk hemorrhage in normal-tension glaucoma.

PURPOSE: To evaluate the morphometric characteristics of the optic disk in eyes with and without disk hemorrhage in normal-tension glaucoma. METHODS: This was a prospective study conducted at Gifu University Hospital of 50 eyes of 50 patients with normal-tension glaucoma (12 men, 38 women; age, 56.5 +/- 14.1 years) who had developed new disk hemorrhage at the time of enrollment and 58 eyes of 58 patients with normal-tension glaucoma (20 men, 38 women; age, 56.7 +/- 12.4 years) with no history of disk hemorrhage during the follow-up period of more than 2 years. Age and global indexes of the visual field were matched. We morphometrically compared the optic disk with and without hemorrhage using a scanning laser tomograph. Global and sector analyses were made of the optic disk structural parameters. RESULTS: There was no significant difference in the global values of the disk parameters between the disk hemorrhage and the nonhemorrhage groups. However, the inferotemporal values for the rim area, rim volume, mean retinal nerve fiber layer thickness, and retinal nerve fiber layer cross-section area in the disk hemorrhage group were significantly smaller than those in the nonhemorrhage group (P <.05). In the disk hemorrhage group, moreover, the values for the rim area, rim volume, and retinal nerve fiber layer cross-section area in the inferotemporal sector with hemorrhage were significantly smaller than those in the same sector without hemorrhage (P <.05). CONCLUSION: Localized damage of the disk rim and retinal nerve fiber layer at the inferotemporal sector was prominent in eyes with disk hemorrhage.

Biphasic intraocular pressure response to calcitonin gene-related peptide.

PURPOSE: To examine the effects of calcitonin gene-related peptide (CGRP) on intraocular pressure (IOP). METHODS: IOP was periodically measured in rabbits treated with intravitreal injection (20 ael) of either: 1) CGRP (10(-4) approximately 10(-7) M) into one eye; 2) CGRP (10(-4) or 10(-6) M) into both eyes 30 min after intravitreal administration of CGRP-(8-37) (10( -3) M), a CGRP1 receptor antagonist, into one eye; 3) CGRP (10(-4 ) or 10(-6) M) into one eye 30 min after intravenous administration (200 mg/kg) of either Nw-nitro-L-arginine methyl ester (L-NAME), a nonselective inhibitor of nitric oxide synthase (NOS), or aminoguanidine (AG), a selective inhibitor of inducible NOS; or 4) CGRP (10(-4) or 10(-6) M) into one eye along with intraperitoneal indomethacin (50 mg/ kg at -1 and 4 h). RESULTS: CGRP (10(-4) and 10(-5) M) produced a biphasic IOP response, which consisted of an early ocular hypertensive phase and a subsequent sustained hypotensive phase. While CGRP (10(-6) M) yielded only a profound IOP reduction. CGRP-(8-37) significantly inhibited the IOP elevation induced by CGRP (10(-4) M) and completely abolished the IOP reduction induced by CGRP (10(-6) M). The IOP increase induced by CGRP (10(-4) M) was completely abolished by L-NAME, but not affected by AG. The IOP reduction induced by CGRP (10(-6) M) was not affected by L-NAME. Indomethacin did not significantly affect the IOP responses to CGRP. CONCLUSIONS: CGRP dose-dependently produces a biphasic IOP response, which is mediated by CGRP1 receptors. It is suggested that constitutive NOS is involved in the early ocular hypertensive response.

Ocular effects of adrenomedullin.

The purpose of this study was to determine the expression and effects of adrenomedullin (AM), a novel vasodilator peptide, in the eye. Expression of AM mRNA was examined in the rat iris-ciliary body using reverse transcription-polymerase chain reaction (RT-PCR). In rabbits, intraocular pressure (IOP) was measured periodically after intravitreal injection (20 microl) of AM (10(-7)-10(-4)m) into one eye. In separate groups of rabbits, 30 min after intravitreal injection of either AM-(22-52) (10(-3)m), a specific AM receptor antagonist, or CGRP-(8-37) (10(-3)m), a CGRP1 receptor antagonist, into one eye, AM (10(-6)m) was injected into both eyes, and IOP was measured. Using different rabbits, aqueous protein and cAMP concentrations were determined 6 hr after injection of AM. Expression of AM mRNA was detected in the rat iris-ciliary body. In rabbits, intravitreally administered AM (10(-6)-10(-4)m) profoundly lowered IOP, and the maximum effect was observed at 4-8 h. The ocular hypotensive effect of AM was dose-dependent (10(-7)-10(-4)m). Pretreatment with CGRP-(8-37) did not significantly inhibit the ocular hypotensive effect of AM (10(-6)m), whereas pretreatment with AM-(22-52) completely abolished it. AM (10(-6)m) did not significantly affect aqueous protein concentration. The higher dose of AM (10(-5)m) induced a significant increase in aqueous protein, which was not associated with an increase in the aqueous cAMP content and was significantly inhibited by AM-(22-52) and CGRP-(8-37). These results demonstrate that AM is expressed in the iris-ciliary body and decreases IOP mainly via specific AM receptors, and suggest that AM may play a role in controlling IOP.

Three new saponins from Tribulus terrestris.

Three new steroidal saponins 1-3, together with five known steroidal saponins, L-mannitol and an inorganic salt were isolated from Tribulus terrestris L. (Zygophyllaceae). The structures of the new steroidal saponins were elucidated as hecogenin 3-O-beta-xylopyranosyl(1-->3)-beta-glucopyranosyl(1-->4)-beta-galactopyr anoside (1), hecogenin 3-O-beta-glucopyranosyl(1-->2)-beta-glucopyranosyl(1-->4)- beta-galactopyranoside (2) and 3-O-[beta-xylopyranosyl(1-->2)-[beta-xylopyranosyl(1-->3)]-beta- glucopyranosyl(1-->4)-[alpha-rhamnopyranosyl(1-->2)]-beta-galactopyranos yl]- 26-O-beta-glucopyranosyl-22-methoxy-(3 beta,5 alpha,25R)-furostan-3,26-diol (3). Structure elucidation was accomplished by 1D and 2D NMR spectra (13C-1H COSY, HMQC, HMBC, 1H-1H COSY, TOCSY, and NOESY), mass spectrometry (FABMS, ESIMS) and chemical methods.