Understanding the role of atmospheric CO 2 during past climate changes requires clear knowledge of how it varies in time relative to temperature. Antarctic ice cores preserve highly resolved records ...of atmospheric CO 2 and Antarctic temperature for the past 800,000 years. Here we propose a revised relative age scale for the concentration of atmospheric CO 2 and Antarctic temperature for the last deglacial warming, using data from five Antarctic ice cores. We infer the phasing between CO 2 concentration and Antarctic temperature at four times when their trends change abruptly. We find no significant asynchrony between them, indicating that Antarctic temperature did not begin to rise hundreds of years before the concentration of atmospheric CO 2 , as has been suggested by earlier studies.
Understanding the role of atmospheric CO2 during past climate changes requires clear knowledge of how it varies in time relative to temperature. Antarctic ice cores preserve highly resolved records ...of atmospheric CO2 and Antarctic temperature for the past 800,000 years. Here we propose a revised relative age scale for the concentration of atmospheric CO2 and Antarctic temperature for the last deglacial warming, using data from five Antarctic ice cores. We infer the phasing between CO2 concentration and Antarctic temperature at four times when their trends change abruptly. We find no significant asynchrony between them, indicating that Antarctic temperature did not begin to rise hundreds of years before the concentration of atmospheric CO2, as has been suggested by earlier studies.
Systemic inflammation is accompanied by profound behavioral and mood changes that resemble symptoms of depression. Findings in animals suggest that pro-inflammatory cytokines released by activated ...immune cells in the periphery evoke these behavioral symptoms by driving inflammatory changes in the brain. However, experimental data in humans are lacking. Here we demonstrate in healthy male volunteers (10 endotoxin treated, 8 placebo treated) that intravenous administration of low-dose endotoxin (0.8 ng/kg body weight), a prototypical pathogen-associated molecular pattern that activates the innate immune system, not only induces a significant increase in peripheral blood cytokine concentrations (that is, tumor necrosis factor-α, interleukin (IL)-6, IL-10) but also results, with some latency, in a robust and selective increase of IL-6 in the cerebrospinal fluid (CSF). Moreover, we found a strong association between the endotoxin-induced increase of IL-6 in the CSF and the severity of mood impairment, with larger increases in CSF IL-6 concentration followed by a greater deterioration in mood. Taken together, these findings suggest that the appearance of depressive symptoms in inflammatory conditions might be primarily linked to an increase in central IL-6 concentration, identifying IL-6 as a potential therapeutic target in mood disorders.
Phage selection of photoswitchable peptide ligands Bellotto, Silvia; Chen, Shiyu; Rentero Rebollo, Inmaculada ...
Journal of the American Chemical Society,
04/2014, Letnik:
136, Številka:
16
Journal Article
Recenzirano
Odprti dostop
Photoswitchable ligands are powerful tools to control biological processes at high spatial and temporal resolution. Unfortunately, such ligands exist only for a limited number of proteins and their ...development by rational design is not trivial. We have developed an in vitro evolution strategy to generate light-activatable peptide ligands to targets of choice. In brief, random peptides were encoded by phage display, chemically cyclized with an azobenzene linker, exposed to UV light to switch the azobenzene into cis conformation, and panned against the model target streptavidin. Isolated peptides shared strong consensus sequences, indicating target-specific binding. Several peptides bound with high affinity when cyclized with the azobenzene linker, and their affinity could be modulated by UV light. The presented method is robust and can be applied for the in vitro evolution of photoswitchable ligands to virtually any target.
The expression levels of intracellular heat shock proteins (Hsps), specialized chaperone proteins, increase in cases of cellular stress with protein misfolding and aggregation. In a previous study, ...we demonstrated that there is an extensive increase in intracellular Hsp27 and 70 expression levels in renal tissues in fire fatality cases. Hsp expression can be induced by not only heat, but also by tissue hypoxia. In cases of fatal hemorrhage, the individual suffers hypoxemia and consequently tissue hypoxia. Here, we examined 43 cases of fatal hemorrhage and a control group of 85 deaths not related to blood loss or temperature exposure. We evaluated Hsp27 and 70 protein expression levels in renal tissue using immunohistochemistry. The results revealed that no extensive Hsp27 or 70 expression is induced in the fatal hemorrhage cases. The renal Hsp levels were similar to those of the control group. Fatal blood loss does not cause relevant cell stress.
•Tissue hypoxia can cause cellular stress even leading to cell death.•Hsps are expressed in case of cell stress to maintain protein homeostasis.•Persistent hypoxidosis causes micromorphological alterations.•Renal tissue is very sensitive to hypoxia.•Fatal hemorrhage does not cause an extensive hsp expression.
Azobenzene, as one of the most prominent molecular switches, is featured in many applications ranging from photopharmacology to information or energy storage. In order to easily and reproducibly ...synthesize non-symmetric substituted azobenzenes in an efficient way, especially on a large scale, the commonly used Baeyer–Mills coupling reaction was adopted to a continuous flow setup. The versatility was demonstrated with a scope of 20 substances and the scalability of this method exemplified by the synthesis of >70 g of an azobenzene derivative applied in molecular solar thermal storage (MOST) systems.
Intermolecular halogen bonds are ideally suited for designing new molecular assemblies because of their strong directionality and the possibility of tuning the interactions by using different types ...of halogens or molecular moieties. Due to these unique properties of the halogen bonds, numerous areas of application have recently been identified and are still emerging. Here, we present an approach for controlling the 2D self-assembly process of organic molecules by adsorption to reactive vs. inert metal surfaces. Therewith, the order of halogen bond strengths that is known from gas phase or liquids can be reversed. Our approach relies on adjusting the molecular charge distribution, i.e., the σ-hole, by molecule-substrate interactions. The polarizability of the halogen and the reactiveness of the metal substrate are serving as control parameters. Our results establish the surface as a control knob for tuning molecular assemblies by reversing the selectivity of bonding sites, which is interesting for future applications.
New photometric and long-slit spectroscopic observations are presented for NGC 7113, PGC 1852, and PGC 67207 which are three bright galaxies residing in low-density environments. The ...surface-brightness distribution is analysed from the KS-band images taken with adaptive optics at the Gemini North Telescope and the ugriz-band images from the Sloan Digital Sky Survey while the line-of-sight stellar velocity distribution and line-strength Lick indices inside the effective radius are measured along several position angles. The age, metallicity, and a-element abundance of the galaxies are estimated from single stellar-population models. In spite of the available morphological classification, images show that PGC 1852 is a barred spiral which we do not further consider for mass modelling. The structural parameters of the two early-type galaxies NGC 7113 and PGC 67207 are obtained from a two-dimensional photometric decomposition and the mass-to-light ratio of all the (luminous and dark) mass that follows the light is derived from orbit-based axisymmetric dynamical modelling together with the mass density of the dark matter halo. The dynamically derived mass that follows the light is about a factor of 2 larger than the stellar mass derived using stellar-population models with Kroupa initial mass function. Both galaxies have a lower content of halo dark matter with respect to early-type galaxies in high-density environments and in agreement with the predictions of semi-analytical models of galaxy formation.
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