CH3NH3PbX3 (X = Cl, Br, I) perovskites were prepared by a self-organization processes using different precursor solutions. The XRD analysis indicates the formation, at room temperature, of a ...tetragonal structure (space group I4/mcm) for X = I, of a cubic structure (space group Pm3̅m) for X = Br, and of centro-symmetric cubic structure (space group Pm3m) for X = Cl, respectively. The structural analysis revealed the formation of CH3NH3Cl as secondary phase in the Cl-containing system. The morphological investigation revealed the formation of rhombo-hexagonal dodecahedra crystallite for X = I, Br, whereas cube-like aggregates were observed for X = Cl. The thermogravimetric analysis performed in air did not reveal any loss until 250 °C for X = I and 300 °C for X = Br, respectively, whereas the differential thermal analysis (DTA) detected two endothermic thermal events (at 336 and 409 °C) for X = I and one only (379 °C) for X = Br, respectively. The infrared spectra (IR) of the powders conformed to the 3-fold symmetry of the methylammonium ion which rotates around the C–N axis. Optical absorption measurements indicated that the CH3NH3PbX3 systems behave as direct-gap semiconductors with energy band gaps of 1.53 eV for X = I, 2.20 eV for X = Br, and 3.00 eV for X = Cl, respectively, at room temperature. The direct-gap semiconductivity for X = I and X = Br was confirmed by the photoluminescence emission measurements, whereas the compound for X = Cl is inactive. I-containing powders were dissolved in an organic solvent (dimethyl-formamide, DMF). The dispersion (100–300 μL) was dropped on glassy substrates on which thick films were obtained by spin-coating and thermal treatment at 120 °C for ca. 5 min. The preparation of the layers was performed in air at room temperature.
Presentation of the scratch assay as a convenient and inexpensive
in vitro tool to gain first insights in the wound healing potential of plant extracts and natural compounds.
The present study deals ...with the optimization of the scratch assay which can be used as an
in vitro model for quantification of fibroblast migration to and proliferation into the wounded area. It is suitable for the first evaluation of the wound re-epithelialization potential of crude herbal extracts, isolated compounds and pharmaceutical preparations. As a proof of concept three preparations from traditional medicinal plants were investigated.
Swiss 3T3 albino mouse fibroblasts were used in monolayers and platelet derived growth factor as positive control. Hexane and ethanolic extracts from
Calendula officinalis and
Matricaria recutita,
Hypericum oil as well as the triterpenoids faradiol myristate and palmitate were studied. To differentiate between proliferation and migration antimitotic mitomycin C was added.
Both extracts of
Calendula officinalis stimulated proliferation and migration of fibroblasts at low concentrations, e.g. 10
μg/ml enhanced cell numbers by 64.35% and 70.53%, respectively. Inhibition of proliferation showed that this effect is mainly due to stimulation of migration. Faradiol myristate and palmitate gave comparable stimulation rates at an almost 50
μg/ml concentration, indicating that they contribute partially, but not most significantly to the wound healing effects of
Calendula preparations. Extracts from
Matricaria recutita were only moderately active.
Hypericum oil was cytotoxic at concentrations higher than 0.5
μg/ml.
The scratch assay in the present form can be used as a promising scientific approach and platform to differentiate between plant extracts known for their wound healing and their anti-inflammatory properties.
Earthquake‐triggered landslides are a significant hazard in seismically active regions, but our ability to assess the hazard they pose in near‐real‐time is limited. In this study, we present a new ...globally applicable model for seismically induced landslides based on the most comprehensive global data set available; we use 23 landslide inventories that span a range of earthquake magnitudes and climatic and tectonic settings. We use logistic regression to relate the presence and distribution of earthquake‐triggered landslides with spatially distributed estimates of ground shaking, topographic slope, lithology, land cover type, and a topographic index designed to estimate variability in soil wetness to provide an empirical model of landslide distribution. We tested over 100 combinations of independent predictor variables to find the best fitting model, using a diverse set of statistical tests. Blind validation tests show that the model accurately estimates the distribution of available landslide inventories. The results indicate that the model is reliable and stable, with high balanced accuracy (correctly versus incorrectly classified pixels) for the majority of test events. A cross‐validation analysis shows high balanced accuracy for a majority of events as well. By combining near‐real‐time estimates of ground shaking with globally available landslide susceptibility data, this model provides a tool to estimate the distribution of coseismic landslide hazard within minutes of the occurrence of any earthquake worldwide for which a U.S. Geological Survey ShakeMap is available.
Key Points
We develop a statistical model to estimate the probability and spatial extent of seismically induced landslides for major earthquakes around the world within minutes after an earthquake occurs
Earthquake‐induced landslides are shown to be related to peak ground velocity, slope, lithology, land cover type, and ground wetness
This model uses globally available data and can be applied in near‐real‐time to any earthquake around the globe for which a USGS ShakeMap is produced
Recent research showed that plant secondary metabolites in pollen may exacerbate the protein-mediated allergic reaction in pollen allergy. It was found that allergenic pollen from various plant ...families contain significant amounts of electrophiles which may covalently bind to nucleophilic groups of proteins, such as thiol moieties. Electrophiles in pollen of the Asteraceae species are typically sesquiterpene lactones, but the nature of electrophilic metabolites in allergenic pollen of other plant families is unknown. We developed a solid-supported cysteinyl probe in order to selectively extract physiologically relevant electrophiles from pollen extracts, and to enable their subsequent characterization by on-line and off-line spectroscopic analysis. The validity of this approach was evaluated with a selection of structurally different model compounds and with a spiked model extract.
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•Small metabolites in pollen may exacerbate the effects of proteins in pollen allergy.•Pollen contain electrophiles that react covalently with thiol groups.•A catch and release approach for the analysis of plant electrophiles is developed.•Solid-phase method allows efficient sample processing and handling of small amounts.
In this study, we present a newly developed, comprehensive dataset of 196 historical earthquakes, including 127 events with known landslide fatality counts, which we use to examine the impact of ...earthquake-induced landslides. Using this dataset, we assess the potential impact of seismically induced landslides on affected populations, based on the exposure of population to expected landslide occurrence. We calculate predicted landslide probabilities out of a global statistical landslide model in the area surrounding each earthquake using USGS’s
ShakeMap
model of strong ground motion. We identify estimated population exposure by comparing the predicted probability grid with a time-corrected global population dataset to determine a predicted
landslide exposure index
. We compare these values to the number of actual fatalities for 91 training events and use these comparisons, together with the United Nations Human Development Index as a vulnerability proxy, to develop a multiple regression model that can potentially be used to provide order-of-magnitude estimates of human impact of earthquake-induced landslides. We observe a significant positive correlation between predicted and observed fatalities, but with very high variability in fatality rates for similar exposure levels, suggesting that other factors (e.g., landslide type and density, the effect of urbanization on population exposure) should be used to improve this estimate. We also demonstrate that these estimates of landslide impacts can be used in a deterministic mode, in collaboration with use of scenario earthquakes, to assess the potential impacts of anticipated future events. With further development, these landslide scenarios can be used by vulnerable communities to improve land use planning, structural design, and emergency response in landslide-prone areas.
Large area processing of organic semiconductors to photovoltaic cells and modules opens up a large potential for commercialization. At the same time, the scale-up of fabrication techniques entails ...evaluation and optimization of several process parameters. In this study, comprising a state-of-the-art absorber polymer (PTB7, together with PCgoBM), we vary processing parameters for blade coated and gravure printed active layers and evaluate their effects on solar cell performance. Thus, efficiencies of up to 3.6% for coated and 1.6% for printed cells on a flexible substrate could be obtained.
Phytochemical studies on Peltodon longipes afforded the isolation of twelve known abietane diterpenes being the active principle. The main diterpene, 7α-acetoxyroyleanone exhibited a similar strong ...cytotoxic activity against a pancreatic and a melanoma cancer cell line as tanshinone IIa the main compound from Salvia miltiorrhiza. Structure–activity relationship study was undertaken including 21 structurally different abietane diterpenes.
Phytochemical investigations of the n-hexane extract from the roots of Peltodon longipes (Lamiaceae) resulted in the isolation of 12 known abietane diterpenes (1–12). Structures were established on the basis of one and two dimensional nuclear magnetic resonance spectroscopic data (1H and 13C, COSY, HSQC and HMBC), electron ionization mass spectrometric analysis (EIMS) as well as comparison with data from literature. These compounds, as well as eight known diterpenes (13–19) from Salvia miltiorrhiza, and two from Salvia sahendica (20 and 21) were evaluated for their cytotoxic effects in human pancreatic (MIAPaCa-2) and melanoma (MV-3) tumor cell lines using the MTT assay. Tanshinone IIa (13), 7α-acetoxyroyleanone (1), 1,2-dihydrotanshinone (16) and cryptotanshinone (14) had the highest cytotoxic effects in MIAPaCa-2, displaying IC50 of 1.9, 4.7, 5.6, and 5.8μM, respectively. Structure–activity relationships of abietane diterpenoid quinones are discussed.
We present and interpret Global Positioning System (GPS) measurements of crustal motions for the period 1988–1997 at 189 sites extending east‐west from the Caucasus mountains to the Adriatic Sea and ...north‐south from the southern edge of the Eurasian plate to the northern edge of the African plate. Sites on the northern Arabian platform move 18±2 mm/yr at N25°±5°W relative to Eurasia, less than the NUVEL‐1A circuit closure rate (25±1 mm/yr at N21°±7°W). Preliminary motion estimates (1994–1997) for stations located in Egypt on the northeastern part of Africa show northward motion at 5–6±2 mm/yr, also slower than NUVEL‐IA estimates (10±1 mm/yr at N2°±4°E). Eastern Turkey is characterized by distributed deformation, while central Turkey is characterized by coherent plate motion (internal deformation of <2 mm/yr) involving westward displacement and counterclockwise rotation of the Anatolian plate. The Anatolian plate is de‐coupled from Eurasia along the right‐lateral, strike‐slip North Anatolian fault (NAF). We derive a best fitting Euler vector for Anatolia‐Eurasia motion of 30.7°± 0.8°N, 32.6°± 0.4°E, 1.2°±0.1°/Myr. The Euler vector gives an upper bound for NAF slip rate of 24±1 mm/yr. We determine a preliminary GPS Arabia‐Anatolia Euler vector of 32.9°±1.2°N, 40.3°±1.1°E, 0.8°±0.2°/Myr and an upper bound on left‐lateral slip on the East Anatolian fault (EAF) of 9±1 mm/yr. The central and southern Aegean is characterized by coherent motion (internal deformation of <2 mm/yr) toward the SW at 30±1 mm/yr relative to Eurasia. Stations in the SE Aegean deviate significantly from the overall motion of the southern Aegean, showing increasing velocities toward the trench and reaching 10±1 mm/yr relative to the southern Aegean as a whole.
BACKGROUND AND PURPOSE Leukotrienes (LTs) are pro‐inflammatory mediators produced by 5‐lipoxygenase (5‐LO). Currently available 5‐LO inhibitors either lack efficacy or are toxic and novel approaches ...are required to establish a successful anti‐LT therapy. Here we provide a detailed evaluation of the effectiveness of the plant‐derived alkaloid tryptanthrin as an inhibitor of LT biosynthesis.
EXPERIMENTAL APPROACH We analysed LT formation and performed mechanistic studies in human neutrophils stimulated with pathophysiologically relevant stimuli (LPS and formyl peptide), as well as in cell‐free assays (neutrophil homogenates or recombinant human 5‐LO) and in human whole blood. The in vivo effectiveness of tryptanthrin was evaluated in the rat model of carrageenan‐induced pleurisy.
KEY RESULTS Tryptanthrin potently reduced LT‐formation in human neutrophils (IC50= 0.6 µM). However, tryptanthrin is not a redox‐active compound and did not directly interfere with 5‐LO activity in cell‐free assays. Similarly, tryptanthrin did not inhibit the release of arachidonic acid, the activation of MAPKs, or the increase in Ca2+i, but it modified the subcellular localization of 5‐LO. Moreover, tryptanthrin potently suppressed LT formation in human whole blood (IC50= 10 µM) and reduced LTB4 levels in the rat pleurisy model after a single oral dose of 10 mg·kg−1.
CONCLUSIONS AND IMPLICATIONS Our data reveal that tryptanthrin is a potent natural inhibitor of cellular LT biosynthesis with proven efficacy in whole blood and is effective in vivo after oral administration. Its unique pharmacological profile supports further analysis to exploit its pharmacological potential.
THE Tien Shan--a high, seismically active intracontinental mountain belt, 1,000-2,000 km north of the Himalaya--has grown as a result of India's collision with Asia1 . The crustal shortening (~ 200 ± ...50 km; refs 2, 3) and thickening that gave rise to the Tien Shan accommodates only a small fraction of India's total penetration into Asia (2,000--3,000km), and the temporal relationship of deformation in this belt to the India-Asia collision remains unclear. Here we report geodetic measurements of the Tien Shan, using the Global Positioning System (GPS), that indicate that the current crustal shortening rate is nearly half of India's convergence rate with Eurasia in this area4 . We infer a total shortening rate for the Tien Shan of ~20 mm yr-1 , which is approximately twice that inferred previously from the extrapolation of slip rates in the Holocene3 and earthquake-induced displacements during this century5 , suggesting that the rate of mountain building in this region has accelerated several-fold since the onset of collision ~50-55 Myr ago6,7 . If, as we argue, the current shortening rate can be extrapolated to geological timescales, then our results suggest that most of the Tien Shan has been constructed during the past 10 Myr, perhaps in response to an increased horizontal force following an abrupt rise of the Tibetan plateau8,9 .
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