The Effect of Cone Opsin Mutations on Retinal Structure and the Integrity of the Photoreceptor Mosaic

Purpose. To evaluate retinal structure and photoreceptor mosaic integrity in subjects with OPN1LW and OPN1MW mutations. Methods. Eleven subjects were recruited, eight of whom have been previously described. Cone and rod density was measured using images of the photoreceptor mosaic obtained from an adaptive optics scanning light ophthalmoscope (AOSLO). Total retinal thickness, inner retinal thickness, and outer nuclear layer plus Henle fiber layer (ONL+HFL) thickness were measured using cross-sectional spectral-domain optical coherence tomography (SD-OCT) images. Molecular genetic analyses were performed to characterize the OPN1LW/OPN1MW gene array. Results. While disruptions in retinal lamination and cone mosaic structure were observed in all subjects, genotype-specific differences were also observed. For example, subjects with “L/M interchange” mutations resulting from intermixing of ancestral OPN1LW and OPN1MW genes had significant residual cone structure in the parafovea (∼25% of normal), despite widespread retinal disruption that included a large foveal lesion and thinning of the parafoveal inner retina. These subjects also reported a later-onset, progressive loss of visual function. In contrast, subjects with the C203R missense mutation presented with congenital blue cone monochromacy, with retinal lamination defects being restricted to the ONL+HFL and the degree of residual cone structure (8% of normal) being consistent with that expected for the S-cone submosaic. Conclusions. The photoreceptor phenotype associated with OPN1LW and OPN1MW mutations is highly variable. These findings have implications for the potential restoration of visual function in subjects with opsin mutations. Our study highlights the importance of high-resolution phenotyping to characterize cellular structure in inherited retinal disease; such information will be critical for selecting patients most likely to respond to therapeutic intervention and for establishing a baseline for evaluating treatment efficacy

Orbital dynamics during an ultrafast insulator to metal transition

Phase transitions driven by ultrashort laser pulses have attracted interest both for understanding the fundamental physics of phase transitions and for potential new data storage or device applications. In many cases these transitions involve transient states that are different from those seen in equilibrium. To understand the microscopic properties of these states, it is useful to develop elementally selective probing techniques that operate in the time domain. Here we show fs-time-resolved measurements of V Ledge Resonant Inelastic X-Ray Scattering (RIXS) from the insulating phase of the Mott- Hubbard material V2O3 after ultrafast laser excitation. The probed orbital excitations within the d-shell of the V ion show a sub-ps time response, which evolve at later times to a state that appears electronically indistinguishable from the high-temperature metallic state. Our results demonstrate the potential for RIXS spectroscopy to study the ultrafast orbital dynamics in strongly correlated materials.Comment: 12 pages, 4 figure

Uranium oxides investigated by X-ray absorption and emission spectroscopies

X-ray absorption and resonant X-ray emission measurements at the O 1s edge of the uranium oxides UO2, U3O8 and UO3 are presented. The spectral shapes of the O Kα X-ray emission spectra of UO3 exhibit significant excitation energy dependence, from an asymmetric to a symmetric form, which differs from those of UO2 and U3O8. This energy dependence is attributed to a significant difference in the oxygen–uranium hybridization between two different sites in the crystal structure of UO3. The spectral shapes of UO2 and U3O8 are also found to be different but without significant energy dependence. The experimental spectra of the valence and conduction bands of the uranium oxides are compared to the results of electronic structure calculations available in the literature

Opportunities for developing thinking in nature observations at the youngest pre-school age

Bakalaura darbu izstrādāja Signija Ātrena, un darba tēma ir „Domāšanas attīstīšanas iespējas dabas vērojumos jaunākajā pirmsskolas vecumā”. Problēmas aktualitāte: visiem cilvēkiem, kuru attīstība bijusi normāla, piemīt spēja domāt. Bērni spēj uztvert, atcerēties, veidot jēdzienus un sazināties. Lai saprastu pasauli, bērnam vispirms jāpievērš tai uzmanība, jāuztver apkārtējie redzes un dzirdes stimuli, jāpatur prātā, kamēr viņš izlemj, ko tie nozīmē un kā uz tiem reaģēt. Šajā darbā autore pēta, vai un kā dabas vērojumi bērnos rosina domāšanas procesus un, ko darīt, lai domāšanas process dabas vērojumos noritētu. Pētījuma mērķis: pētīt bērnu domāšanas attīstīšanas iespējas dabas vērojumos jaunākajā pirmsskolas vecumā. Pirmajā nodaļā autore sniedz vispārīgu jēdziena ‘domāšana’ raksturojumu no psihologu un pedagogu atziņām. Gan psihologi, gan filozofi ir vienisprātis, ka domāšana ir cieši saistīta ar runu. Kad cilvēkam rodas vajadzība saprast, tad viņš sāk domāt. Otrajā nodaļā autore apraksta domāšanas attīstīšanas paņēmienus pedagoģiskajā procesā teorijā un izstrādā paņēmienus, ko izmantot arī praksē. Bērni ir lieli pētnieki, zinātkāri un ar vēlmi izprast. Daba nodrošina iespēju pētīt, domāt un izzināt. Trešajā nodaļā autore veic pētījumu, lai pārliecinātos, vai gūtās un izstrādātās teorētiskās atziņas apstiprinās arī praksē. Saskaroties dabā ar dzīvajām būtnēm, bērni kļūst atvērtāki, viņos sāk darboties pētnieka instinkts un viņi vēlas izzināt, viņiem rodas jautājumi, uz kuriem rast atbildes. Atslēgas vārdi: Jaunākais pirmsskolas vecums, domāšana, domāšanas attīstība, dabas vērojumi. Darbs sastāv no 51 lapaspusēm, tajā ir 7 attēli, 1 tabula, 4 diagrammas, izmantotas 32 literatūras vienības.Bachelor work was developed by Signija Ātrena and title is „Opportunities for developing thinking in nature observations at the youngest pre-school age”. Topicality of the problem: all people with normal development have the ability to think. Children are able to perceive, remember, form concepts and communicate. To understand the world, the child must first pay attention to it, perceive the surrounding visual and auditory stimuli, and keep in mind while deciding what they mean and how to respond to them. In this work, the author explores whether and how nature observations in children stimulate thinking processes and what to do to make the thinking process happen. The aim of the study: to study the possibilities of developing children's thinking in nature observation at the youngest pre-school age. In the first chapter, the author gives a general description of the concept of 'thinking' from psychologists and educators. Both psychologists and philosophers agree that thinking is closely related to speech. When person needs to understand, he begins to think. In the second chapter, the author describes ways of developing thinking in the pedagogical process in theory and develops techniques that can be used in practice. Children are great researchers, curious and eager to understand. Nature provides the opportunity to explore, think and cognize. In the third chapter, the author carries out a research to make sure that the theoretical findings gained and developed will be validated in practice. Faced with living beings in nature, children become more open, have the instinct of a researcher, and they want to cognize and have questions to answer. Key words: youngest preschool age, thinking, thinking development, nature observations. The work consists of 51 pages, 7 pictures, 1 table, 4 diagrams, 32 literary units

The Effect of Cone Opsin Mutations on Retinal Structure and the Integrity of the Photoreceptor MosaicEffect of Opsin Mutations on Photoreceptor Phenotype

PurposeTo evaluate retinal structure and photoreceptor mosaic integrity in subjects with OPN1LW and OPN1MW mutations.MethodsEleven subjects were recruited, eight of whom have been previously described. Cone and rod density was measured using images of the photoreceptor mosaic obtained from an adaptive optics scanning light ophthalmoscope (AOSLO). Total retinal thickness, inner retinal thickness, and outer nuclear layer plus Henle fiber layer (ONL+HFL) thickness were measured using cross-sectional spectral-domain optical coherence tomography (SD-OCT) images. Molecular genetic analyses were performed to characterize the OPN1LW/OPN1MW gene array.ResultsWhile disruptions in retinal lamination and cone mosaic structure were observed in all subjects, genotype-specific differences were also observed. For example, subjects with "L/M interchange" mutations resulting from intermixing of ancestral OPN1LW and OPN1MW genes had significant residual cone structure in the parafovea (∼25% of normal), despite widespread retinal disruption that included a large foveal lesion and thinning of the parafoveal inner retina. These subjects also reported a later-onset, progressive loss of visual function. In contrast, subjects with the C203R missense mutation presented with congenital blue cone monochromacy, with retinal lamination defects being restricted to the ONL+HFL and the degree of residual cone structure (8% of normal) being consistent with that expected for the S-cone submosaic.ConclusionsThe photoreceptor phenotype associated with OPN1LW and OPN1MW mutations is highly variable. These findings have implications for the potential restoration of visual function in subjects with opsin mutations. Our study highlights the importance of high-resolution phenotyping to characterize cellular structure in inherited retinal disease; such information will be critical for selecting patients most likely to respond to therapeutic intervention and for establishing a baseline for evaluating treatment efficacy