ABSTRACT
Two-dimensional (2D) antimonene, bismuthene, and their binary compound 2D BiSb possess high spin-orbit coupling (SOC) and potential topological insulator properties upon engineering their structural and chemical properties. Based on many-body first-principles calculations, we show that these materials can exhibit isotropic or anisotropic optoelectronic properties depending on their geometry, i.e. buckled (hb) or asymmetrical washboard (aw) phases. SOC significantly alters their optoelectronic properties, which is predominantly evident in 2D bismuthene. hb-antimonene absorbs light in the visible and partially in the ultraviolet regimes, while the absorption band edge for aw-antimonene, hb- and aw-bismuthene is set at the infrared region, absorption being spread as a broadband optical response through the spectral range. An exciton binding with 0.18 eV energy is detected for hb-bismuthene. Due to their broadband optical response, antimonene, bismuthene, and their binary compound offer possibilities towards applications as 2D materials in solar cells, light-emitting devices, photodetectors and light modulation.
ABSTRACT
A suspended single layer of GaN in a honeycomb structure is stable in a planar geometry. By stacking these GaN layers one can construct bilayers or multilayers, even new three-dimensional (3D) periodic structures. In this study, we clarified how the planar layers are buckled with the onset of vertical Ga-N bonds. Among the four stable phases of bilayer GaN, only one of them maintains the planar geometry, which is bound by weak van der Waals interactions. For the remaining three phases, the layers are buckled with the onset of weak vertical bonds, and attain total energies slightly lower than that of the planar geometry. Structural phase changes, as well as direct-indirect band transitions take place under strain and electrostatic charging. The vertical bonds become shorter in multilayers, and eventually attain the bulk value. Among the stable phases of 3D periodic GaN, only one with a graphite-like structure behaves as a layered, van der Waals solid; whereby others are 3D uniform crystals beyond the van der Waals solid.
ABSTRACT
Following its synthesis, borophene has drawn noticeable attention due to its remarkable intrinsic properties. Understanding and modifying these properties are crucial for implementation of borophene in high-technological applications. In this study, we employed ab initio techniques to examine the variation of the optoelectronic properties of buckled borophene by strain and surface functionalization. We find that the optical response can be tuned by applying compressive/tensile strain and covering the surface with hydrogen and fluorine atoms. It is shown that the variations in optical properties can be correlated with structural deformations and modifications in the electronic band structure. Revealing the tunability of the optical response of borophene can pave the way for its potential uses in various optoelectronic devices.
ABSTRACT
OBJECTIVE: To present the influence of dexamethasone intravitreal implant due to macular edema in non-infectious uveitis in the fellow eye. PATIENTS AND METHODS: A 25-year-old patient with a long history of juvenile arthritis with concomitant recurrent bilateral uveitis, complicated with increases of intraocular pressure and macular edema was treated with a single intravitreal dexamethasone implant into the eye with lower visual acuity. RESULTS: During a 36-month follow-up, the patient's bilateral visual acuity improved. The retinal thickness in both maculae decreased. CONCLUSIONS: Treating macular edema in the course of recurrent uveitis accompanying a systemic disease with dexamethasone depot in vitreous may play a beneficial role also in the fellow eye, when affected. This therapeutic effect in the fellow eye may suggest that the medication can penetrate into the circulatory system and reach such other organs as the fellow eye.
Subject(s)
Anti-Inflammatory Agents/administration & dosage , Dexamethasone/administration & dosage , Intravitreal Injections/methods , Uveitis/diagnosis , Uveitis/drug therapy , Adult , Drug Implants , Glucocorticoids/therapeutic use , Humans , Intraocular Pressure/physiology , Macular Edema/complications , Macular Edema/diagnosis , Macular Edema/drug therapy , Male , Treatment Outcome , Uveitis/etiology , Visual Acuity/drug effects , Visual Acuity/physiologyABSTRACT
Vitreous amyloidosis, a rare condition characteristic of the familial form of systemic amyloidosis with polyneuropathy, is caused by a mutation in the transthyretin (TTR) gene. Herein we have presented 2 sisters with involvement of the vitreous body, which prompted a subsequent diagnosis of the TTR-related, familial form of systemic amyloidosis. Due to the progressive character of the disease and poor prognosis, the patients have been considered for liver transplantation, which at present is the only treatment option for this disease.
Subject(s)
Amyloid Neuropathies, Familial/genetics , Amyloid Neuropathies, Familial/surgery , Liver Transplantation/physiology , Prealbumin/genetics , Adult , Amyloid Neuropathies, Familial/diagnostic imaging , Diagnosis, Differential , Disease Progression , Female , Humans , Mutation , Siblings , Ultrasonography , Vitreous Body/pathologyABSTRACT
We present two patients who developed keratitis sicca and pemphigoid-like symptoms following allogeneic bone marrow transplantation (BMT). The diagnosis of ocular graft-versus-host disease (GvHD) was considerably delayed in both. They were admitted to the reference ophthalmology and posttransplant care departments years after allogeneic BMT, when skin biopsy revealed changes typical for chronic GvHD. In both cases either systemic or local immunosuppressive treatment led to improvement of the clinical condition but did not significantly change patients' quality of life.
Subject(s)
Bone Marrow Transplantation/adverse effects , Eye Diseases/etiology , Graft vs Host Disease/etiology , Pemphigoid, Bullous/etiology , Adult , Female , Graft vs Host Disease/drug therapy , Humans , Immunosuppressive Agents/therapeutic use , Male , Skin/pathology , Transplantation, Homologous , Treatment OutcomeABSTRACT
Tolpa Peat Preparation (TPP) administered in various doses does not influence the ability of mononuclear cells (MNC) obtained from diabetic patients with proliferative retinopathy to induce neovascularization response in H-LIA test. Methylxanthines (theophylline, theobromine) significantly decrease the angiogenic activity of these cells. The therapeutic value of these drugs in proliferative retinopathy should be evaluated.
Subject(s)
Amino Acids/pharmacology , Carbohydrates/pharmacology , Diabetic Retinopathy/pathology , Humic Substances/pharmacology , Leukocytes, Mononuclear/drug effects , Neovascularization, Pathologic/etiology , Theobromine/pharmacology , Theophylline/pharmacology , Uronic Acids/pharmacology , Adolescent , Adult , Animals , Child , Drug Combinations , Humans , Leukocytes, Mononuclear/physiology , Mice , Mice, Inbred BALB C , SoilABSTRACT
Twenty four patients with retinal pigment dystrophy were subjected to examination of pupillary reaction. Evaluated was the amplitude of pupillary reaction on a standard light flash. The results received were compared with the field changes. It was noted that the amplitude is diminished depending on the changes in the visual field.
Subject(s)
Reflex, Pupillary/physiology , Retinitis Pigmentosa/diagnosis , Visual Acuity/physiology , Visual Fields/physiology , Adolescent , Adult , Child , Electroretinography , Humans , Light , Middle Aged , Retinitis Pigmentosa/physiopathologyABSTRACT
Presented is a case of uveal melanoma in the posterior segment of the eye. It has been accompanied by an inflammatory reaction of the anterior segment which made impossible the visual evaluation of the fundus.
Subject(s)
Choroid Neoplasms/diagnosis , Iridocyclitis/diagnosis , Melanoma/diagnosis , Retinal Detachment/diagnosis , Choroid Neoplasms/complications , Choroid Neoplasms/surgery , Diagnosis, Differential , Eye Enucleation , Humans , Iridocyclitis/complications , Iridocyclitis/surgery , Male , Melanoma/complications , Melanoma/surgery , Retinal Detachment/complications , Retinal Detachment/surgeryABSTRACT
Presented is the initial clinical evaluation of Ocuflur, a compound of Allergan. The influence of the drug on the size of the pupil and the reaction of the pupil to a light flash was tested in volunteer subjects. The efficacy of the drug was tested intraoperatively.
Subject(s)
Cataract Extraction , Flurbiprofen/administration & dosage , Pupil/drug effects , Flurbiprofen/pharmacology , Humans , Mydriatics , Ophthalmic Solutions , Premedication , Pupil/physiologyABSTRACT
Presented are the results of a 3 years long observation of the pupillary reaction in patients with pigmentary retinal dystrophy who have been subjected to a complex treatment. The authors discovered a consistency between the changes in the visual field and the amplitude of the pupillary reaction.
Subject(s)
Iontophoresis , Lighting , Pupil Disorders/therapy , Pupil/physiology , Retinitis Pigmentosa/therapy , Tolazoline/administration & dosage , Ultrasonic Therapy , Xanthinol Niacinate/administration & dosage , Combined Modality Therapy , Dark Adaptation/drug effects , Dark Adaptation/physiology , Humans , Pupil/drug effects , Pupil Disorders/etiology , Pupil Disorders/physiopathology , Retinitis Pigmentosa/complications , Retinitis Pigmentosa/physiopathologyABSTRACT
The reaction of the pupil for light was checked in 25 patients with an unilateral retinal detachment. The sore eye and the fellow-eye were examined separately. The deterioration of the reaction was dependent on the area of detachment and on the condition of the macula.
Subject(s)
Pupil Disorders/etiology , Pupil/physiology , Reflex, Pupillary/physiology , Retinal Detachment/physiopathology , Adolescent , Adult , Aged , Humans , Middle Aged , Photic Stimulation/methods , Pupil Disorders/diagnosis , Retinal Detachment/complicationsABSTRACT
The pupillary diameter was checked in illumination of various intensity in 20 patients with unilateral retinal detachment. The healthy and the diseased eye were examined separately. The authors discovered a latent anisocoria the amount of which was dependent on the condition of the macular area and on the extent of the detachment.
