Sedimentology of the Late Quaternary Wadi Hasa Marl Formation of Central Jordan: a record of climate variability

The sedimentary features and fossils within the Wadi Hasa Marl Formation coupled with optical luminescence chronology indicate alternating wet and dry periods have occurred on the Jordanian plateau since the last interglacial. The Jurf Ed Darawish Member rests unconformably on the Maastrichtian Muwaqqar Chalk Marl Formation and is composed predominantly of poorly sorted, clast-supported conglomerate. Palaeocurrents and clast composition indicate provenance from Cretaceous sedimentary rocks and Tertiary basalts to the west and southwest of the study site and the facies suggest a flashy alluvial depositional environment probably similar to the modern wadis. The overlying Burma Member consists of bedded grey-green clayey silts and marls with calcrete profiles, up to 1.2 m thick, and isolated gravel lenses. The fine-grained sediments contain charophytes, ostracods, bivalves and various species of gastropod indicating normal freshwater lacustrine conditions. The calcretes contain a poorly preserved fauna suggesting lacustrine deposition followed by subaerial exposure and pedogenesis. Three optical luminescence ages have been obtained from the Burma Member which suggest that the member ranges in age from >111 ka through to <40 ka. The facies variations are indicative of climatic fluctuations in Jordan during this period and human artefacts are found embedded in the sediments. This preliminary study suggests that the Late Quaternary central Jordan sedimentary record may preserve valuable evidence of complex climatic variation which will supplement the data from the Jordan Valley where tectonic activity complicates the sedimentary record.     

Growth and luminescence of luminous bacteria promoted by agents of microbial origin

The examination of four species of luminous bacteria Photobacterium leiognathi, Photobacterium phosphoreum, Vibrio fischeri and Vibrio harveyi has enabled us to reveal some nutrient medium components effecting growth, luminescence intensity and luciferase synthesis. These agents are nucleic components (nucleotides, nucleosides and amine bases), amino acids and vitamins, which are part of hydrolysates from the biomass of various lithotrophic microorganisms, hydrogen-oxidizing, ironoxidizing and carboxydobacteria. The effect of promoting agents essentially alters the physiological state and ultrastructure of the cells of luminous bacteria and increases luciferase biosynthesis two- to three-fold compared to a control.     

Effects of isoflurane on measurements of delayed lumininescence in Acetabularia acetabulum.

The volatile halogenated methyl ethyl ether, isoflurane, used as an anaesthetic, inhibits actin-based dynamics directly or indirectly in animal cells. In plant cells, most intracellular movements are related to actin pathways. We have used isoflurane in a unicellular alga, Acetabularia acetabulum, to test the dynamics of choloroplast organization. By measuring the delayed luminescence, we found that isoflurane worked efficiently in the unicellular organism and showed dose- and time-course-dependent actin-inhibition patterns. When A. acetabulum was treated with saturated solutions of isoflurane in artificial seawater (defined as 100% isoflurane) for 3 or 6 min, the delayed luminescence (DL) was decreased and was never recovered. In contrast, if treated with 75% diluted isoflurane, the DL was firstly inhibited and then recovered several hours later, and if treated with 50% diluted isoflurane, the change of DL was small. Our work proved that isoflurane can affect actin-related pathways in both animals and plants.     

Delayed luminescence of Prorocentrum minimum under controlled conditions

Delayed luminescence (DL), also termed delayed fluorescence or delayed light emission, is the phenomenon of long-lived light emission by plants and cyanobacteria after being illuminated with light and put into darkness. Culture growth of three Prorocentrum minimum strains was studied with DL measurements. DL decay kinetics was measured from 1–60 s after a pulse of white light. The strains used were from the Adriatic Sea (PmK), from Chesapeake Bay, USA (D5), and from the Baltic Sea (BAL), cultured at salinity of 32, 16, and 8 (practical salinity scale), respectively. The strains differed in cell size and chlorophyll a content (PmK > D5 > BAL), as well as in DL parameters. The DL results were compared to standard measurements of culture density and carbon content (calculated from biovolumes). DL decay curves had a specific peak, which changed with culture growth and showed more similarities between the strains PmK and D5. The DL intensity increased with cell density and carbon content in a two-stage process, corresponding to the lag and exponential phases of growth. DL intensity was best correlated with carbon content irrespective of strain and is proposed as an estimate of biomass and for differentiating between lag and exponential phases of growth.     

Gaussia分泌型萤光素酶的研究进展及其应用

Gaussia分泌型萤光素酶是近年发现的一种来源于海洋桡脚类动物Gaussia princeps的新型分泌型萤光素酶,是目前已知的可自然分泌的最小萤光素酶,因其分子小、灵敏度高、半衰期短和可高效分泌,而成为一种理想的报告基因,广泛应用于体内外研究。我们就Gaussia分泌型萤光素酶的发光原理、荧光特性及其应用等进行简要综述。     

The structure and luminescence properties of Mn2+/Eu2+/Er3+‐doped MgO‐Ga2O3‐SiO2 glasses and glass‐ceramics

The MgO–Ga₂O₃–SiO₂ glasses and glass‐ceramics samples doped with Eu²⁺/Mn²⁺/Er³⁺ and heated in reductive atmosphere were prepared by the sol–gel method. The structure, morphology and the luminescence properties were studied using X‐ray diffraction, high‐resolution transmission electron microscope, fluorescence spectra, and up‐conversion emission. The luminescence characteristics of doped ions could be influenced by temperature and matrix component. The characteristic emission of Mn²⁺, Eu²⁺ and Er³⁺ were seen and the energy transfer efficiency from Eu²⁺ to Mn²⁺ was enhanced as Mn²⁺ concentration was increased. In addition, the two‐photon process was determined for the Er³⁺‐doped samples.     

Imaging Spatial Variations of Optical Bandgaps in Perovskite Solar Cells

A fast, nondestructive, camera‐based method to capture optical bandgap images of perovskite solar cells (PSCs) with micrometer‐scale spatial resolution is developed. This imaging technique utilizes well‐defined and relatively symmetrical band‐to‐band luminescence spectra emitted from perovskite materials, whose spectral peak locations coincide with absorption thresholds and thus represent their optical bandgaps. The technique is employed to capture relative variations in optical bandgaps across various PSCs, and to resolve optical bandgap inhomogeneity within the same device due to material degradation and impurities. Degradation and impurities are found to both cause optical bandgap shifts inside the materials. The results are confirmed with micro‐photoluminescence spectroscopy scans. The excellent agreement between the two techniques opens opportunities for this imaging concept to become a quantified, high spatial resolution, large‐area characterization tool of PSCs. This development continues to strengthen the high value of luminescence imaging for the research and development of this photovoltaic technology.     

High‐Voltage Photogeneration Exclusively via Aggregation‐Induced Triplet States in a Heavy‐Atom‐Free Nonplanar Organic Semiconductor

The electron–hole recombination kinetics of organic photovoltaics (OPVs) are known to be sensitive to the relative energies of triplet and charge‐transfer (CT) states. Yet, the role of exciton spin in systems having CT states above 1.7 eV—like those in near‐ultraviolet‐harvesting OPVs—has largely not been investigated. Here, aggregation‐induced room‐temperature intersystem crossing (ISC) to facilitate exciton harvesting in OPVs having CT states as high as 2.3 eV and open‐circuit voltages exceeding 1.6 V is reported. Triplet excimers from energy‐band splitting result in ultrafast CT and charge separation with nonradiative energy losses of <250 meV, suggesting that a 0.1 eV driving force is sufficient for charge separation, with entropic gain via CT state delocalization being the main driver for exciton dissociation and generation of free charges. This finding can inform engineering of next‐generation active materials and films for near‐ultraviolet OPVs with open‐circuit voltages exceeding 2 V. Contrary to general belief, this work reveals that exclusive and efficient ISC need not require heavy‐atom‐containing active materials. Molecular aggregation through thin‐film processing provides an alternative route to accessing 100% triplet states on photoexcitation.