Search results for "PHOTOS"

Pyrrolo[2,3-h]quinolinones: A new ring system with potent photoantiproliferative activity

2006

A new class of compounds, the pyrrolo[2,3-h]quinolin-2-ones, nitrogen isosters of the angular furocoumarin Angelicin, was synthesized with the aim of obtaining new photochemotherapeutic agents with increased antiproliferative activity and lower undesired toxic effects than the lead compound. Two synthetic pathways were approached to allow the isolation both of the dihydroderivatives 10-17 and of the aromatic ring system 23. Compounds 10-17 showed a remarkable phototoxicity and a great UVA dose dependence reaching IC(50) values at submicromolar level. Intracellular localization of these compounds has been evaluated by means of fluorescence microscopy using tetramethylrhodamine methyl ester a…

Latvijas Universitāte ilustrācijās

1929

Grāmatā publicēti fotoattēli par Latvijas Universitātes pirmajiem 10 darbības gadiem. Lielākā daļa ir K. Rakes fotogrāfijas, kā arī darbi no "Klio", Zvirbuļa, Lapiņa, Baula u. c. fotodarbnīcām.

Seasonal and Inter-annual Variation of Evapotranspiration in Amazonia Based on Precipitation, River Discharge and Gravity Anomaly Data

2019

We analyzed seasonal and spatial variations of evapotranspiration (ET) for five Amazon sub-basins and their response to the 2015/16 El Nino episode using a recently developed water-budget approach. ET varied typically between similar to 7 and 10 cm/month with exception of the Xingu basin for which it varied between 10 and 15 cm/month. Outstanding features of ET seasonality are (i) generally weak seasonality, (ii) two ET peaks for the two very wet catchments Solimoes and Negro, with one occurring during the wet season and one during the drier season, and (iii) a steady increase of ET during the second half of the dry season for the three drier catchments (Madeira, Tapajos, Xingu). Peak ET oc…

Sulfur Dioxide Oxidation Catalyzed by Photosensitized Ytterbium Diphthalocyanine

2008

Oxidation of SO2 into SO3 was found effectively catalyzed by photosensitized ytterbium diphthalocyanine, YbPc2 (Pc = phthalocyanine ligand, C32H16N8) when performed in air-saturated dimethylformamide (DMF) solution at 20 °C. The process follows according to a multi-step complex mechanism involving chemical induction as its driving force. Excitation energy of the sandwich molecular system in YbPc2 is used to promote the reaction by creating a reactive intermediate form of the ytterbium complex hosting up to eight SO2 molecules. The conversion of SO2 proved complete.

Selective Stepwise Suzuki Cross-Coupling Reaction for the Modelling of Photosynthetic Donor−Acceptor Systems

2009

A Suzuki reaction performed as a selective stepwise substitution of two boryl groups on a diarylporphyrin precursor is reported for straightforward construction of a porphyrin trimer, modeling photosynthetic donor-acceptor systems.

Photosynthesis mediates expression of Sorghum bicolor transporters in arbuscular mycorrhizal symbiosis

2014

Virtuālā izstāde "Fotogrāfiju albums “Prezidiju konventa vīru kora koncertceļojums uz Zviedriju un Norvēģiju”"

2018

Par Latvijas Universitātes Muzeja 2018. gada augusta mēneša priekšmetu tika izvēlēts fotogrāfiju albums “Prezidiju konventa vīru kora koncertceļojums uz Zviedriju un Norvēģiju”. Vairāk par to iespējams uzzināt tam veltītajā virtuālajā izstādē, kurā apskatāmas izteiksmīgākās fotogrāfijas no albuma par Prezidiju konventa vīru kora koncertceļojumu uz Zviedriju un Norvēģiju 1937. gadā.

Solar Coronal Loops Associated with Small-scale Mixed Polarity Surface Magnetic Fields

2017

L. P. Chitta et. al.

Proton‐Gated Ring‐Closure of a Negative Photochromic Azulene‐Based Diarylethene

2020

Abstract Proton‐responsive photochromic molecules are attractive for their ability to react on non‐invasive rapid optical stimuli and the importance of protonation/deprotonation processes in various fields. Conventionally, their acidic/basic sites are on hetero‐atoms, which are orthogonal to the photo‐active π‐center. Here, we incorporate azulene, an acid‐sensitive pure hydrocarbon, into the skeleton of a diarylethene‐type photoswitch. The latter exhibits a novel proton‐gated negative photochromic ring‐closure and its optical response upon protonation in both open and closed forms is much more pronounced than those of diarylethene photoswitches with hetero‐atom based acidic/basic moieties. …

Identifying a marine microalgae with high carbohydrate productivities under stress and potential for efficient flocculation

2018

Microalgal biomass represents a potential third generation feedstock that could be utilised as a source of carbohydrates for fermentative production of a range of platform biochemicals. Identifying microalgal strains with high biomass and carbohydrate productivities while also being amenable to downstream processes is key in improving the feasibility of these processes. Utilising marine microalgae capable of growing in seawater will decrease reliance on freshwater resources and improve the sustainability of production. This study screened several marine microalgae believed to accumulate carbohydrates to find new high performing strains. Four strains had high growth rates and accumulated car…