Carbon nanotubes quench singlet oxygen generated by photosynthetic reaction centers

Photosensitizers may convert molecular oxygen into reactive oxygen species (ROS) including, e.g., singlet oxygen (1O2), superoxide anion (O2-•), and hydroxyl radicals (•OH), chemicals with extremely high cyto- and potential genotoxicity. Photodynamic ROS reactions are determinative in medical photodynamic therapy (cancer treatment with externally added photosensitizers) and in reactions damaging the photosynthetic apparatus of plants (via internal pigments). The primary events of photosynthesis take place in the chlorophyll containing reaction center protein complex (RC), where the energy of light is converted into chemical potential. 1O2 is formed by both bacterial bacteriochlorophylls and plant RC triplet chlorophylls in high light and if the quenching of 1O2 is impaired. In plant physiology, reducing the formation of the ROS and thus lessening photooxidative membrane damage (including the RC protein) and increasing the efficiency of the photochemical energy conversion is of special interest. Carbon nanotubes, in artificial systems, are also known to react with singlet oxygen. To investigate the possibility of 1O2 quenching by carbon nanotubes in a biological system, we studied the effect of carbon nanotubes on 1O2 photogenerated by photosynthetic RCs purified from purple bacteria. 1,3-Diphenylisobenzofuran (DPBF), a dye responding to oxidation by 1O2 with absorption decrease at 420nm was used to measure 1O2 concentrations. 1O2 was produced either from a photosensitizer (methylene blue) or from triplet photosynthetic RCs and the antioxidant capacity of carbon nanotubes was assessed. Less 1O2 was detected by DPBF in the presence of carbon nanotubes, suggesting that these are potential quenchers of this ROS. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Are European decision-makers preparing for high-end climate change?

Despite the Paris Agreement target of holding global temperature increases 1.5 to 2 °C above pre-industrial levels, high-end climate change (HECC) scenarios going beyond 4 °C are becoming increasingly plausible. HECC may imply increasing climate variability and extremes as well as the triggering of tipping points, posing further difficulties for adaptation. This paper compares the outcomes of four concurrent European case studies (EU, Hungary, Portugal, and Scotland) that explore the individual and institutional conditions, and the information used to underpin adaptation-related decision-making in the context of HECC. The focus is on (i) whether HECC scenarios are used in current adaptation-related decision-making processes; (ii) the role of uncertainty and how climate and non-climate information is used (or not) in these processes; and (iii) the information types (including socio-economic drivers) commonly used and their limitations in relation to HECC scenarios. Decision-makers perceive HECC as having a low probability or distant occurrence and do not routinely account for HECC scenarios within existing climate actions. Decision-makers also perceive non-climate drivers as at least as important, in many cases more important, than climate change alone. Whilst more information about the implications of particular sectoral and cross-sectoral impacts is needed, climate change uncertainty is not a significant barrier to decision-making. Further understanding of individual and institutional challenges brought about by the ‘squeeze’ between adapting to HECC scenarios or to lower levels of temperature change (as those agreed in Paris) is essential to better contextualise the use of climate change information.info:eu-repo/semantics/publishedVersio

Photocatalytic activity of N-TiO2 nanotubes decorated with CdS QD

The negative consequences of the modern world are environmental pollution. To decrease it, a lot of research is focused on finding solution for its remediation. Photoactive materials have ability to utilize solar energy for the degradation of organic and inorganic pollutants. Among different photoactive material TiO2 has advantages due to its non-toxicity, chemical stability and corrosion resistance. The aim of this study was to investigate the synergetic effect of nitrogen incorporation into crystal structure of TiO2 and deposition of CdS onto amelioration of the photocatalytic degradation of methylen orange compared to the pristine TiO2. For that purpose TiO2 nanotubes were obtained by anodization of titanium foil in HF containing electrolyte. To achieve crystal structure and at the same time to introduce nitrogen in TiO2, the samples were annealed in ammonia atmosphere at 450 °C, for different time of annealing. The highest amount of nitrogen was achieved for the shortest time of annealing (30 min). Beside that, it was observed that the highest level of interstitial nitrogen was also achieved for the shortest time of annealing. Further, CdS quantum dots (QDs) were deposited on the nitrogen doped TiO2 nanotubes via an ex-situ method (using binding reagent). According to the FESEM micrographs, a partial agglomeration of CdS QDs on some domaines on top of the nanotubes was observed. By performing the DRS, the improvement of the optical response after nitrogen doping and deposition of CdS was demonstrated. The sample with the highest amount of total nitrogen and interstitial nitrogen in combination with deposition CdS QDs exhibited the highest photocatalytic efficiency

The transcription factor EGR2 is the molecular linchpin connecting STAT6 activation to the late, stable epigenomic program of alternative macrophage polarization

Macrophages polarize into functionally distinct subtypes while responding to microenvironmental cues. The identity of proximal transcription factors (TFs) downstream from the polarization signals are known, but their activity is typically transient, failing to explain the long-term, stable epigenomic programs developed. Here, we mapped the early and late epigenomic changes of interleukin-4 (IL-4)-induced alternative macrophage polarization. We identified the TF, early growth response 2 (EGR2), bridging the early transient and late stable gene expression program of polarization. EGR2 is a direct target of IL-4-activated STAT6, having broad action indispensable for 77% of the induced gene signature of alternative polarization, including its autoregulation and a robust, downstream TF cascade involving PPARG. Mechanistically, EGR2 binding results in chromatin opening and the recruitment of chromatin remodelers and RNA polymerase II. Egr2 induction is evolutionarily conserved during alternative polarization of mouse and human macrophages. In the context of tissue resident macrophages, Egr2 expression is most prominent in the lung of a variety of species. Thus, EGR2 is an example of an essential and evolutionarily conserved broad acting factor, linking transient polarization signals to stable epigenomic and transcriptional changes in macrophages

Membrane fluidity matters: Hyperthermia from the aspects of lipids and membranes

Hyperthermia is a promising treatment modality for cancer in combination both with radio- and chemotherapy. In spite of its great therapeutic potential, the underlying molecular mechanisms still remain to be clarified. Due to lipid imbalances and 'membrane defects' most of the tumour cells possess elevated membrane fluidity. However, further increasing membrane fluidity to sensitise to chemo-or radiotherapy could have some other effects. In fact, hyperfluidisation of cell membrane induced by membrane fluidiser initiates a stress response as the heat shock protein response, which may modulate positively or negatively apoptotic cell death. Overviewing some recent findings based on a technology allowing direct imaging of lipid rafts in live cells and lipidomics, novel aspects of the intimate relationship between the 'membrane stress' of tumour cells and the cellular heat shock response will be highlighted. Our findings lend support to both the importance of membrane remodelling and the release of lipid signals initiating stress protein response, which can operate in tandem to control the extent of the ultimate cellular thermosensitivity. Overall, we suggest that the fluidity variable of membranes should be used as an independent factor for predicting the efficacy of combinational cancer therapies

Influence of local exposure to static magnetic field on pain perception and bone turnover of osteoporotic patients with vertebral deformity - a randomized controlled trial

Purpose: Static magnetic field (SMF) could improve pain sensation and bone turnover. In a single-center randomized double-blind placebo-controlled study we investigated the effects of SMF exposure on subjective pain and bone turnover. Materials and methods: Postmenopausal osteoporotic women (aged 50-70 years) with bone deformity and back pain were randomized to 10 weekly visits of 30-min SMF (n = 6) or treatment with non-magnetized pads (n = 5) on the back. Primary and secondary outcomes were changes in pain sensation on a visual analogue scale (VAS) during each visit and over 10 weeks, respectively. Tertiary outcomes were changes in osteocalcin and beta-crosslaps. SMF was inhomogeneous with 192 millitesla peak-to-peak value by 19 tesla/meter gradient of the magnetic flux density at 3 mm. Results: Participants randomized to sham had higher VAS at baseline (mean difference: 2.8, 95% confidence interval (CI) 0.47-5.2 cm). Both SMF and sham similarly reduced short term pain (sham-SMF: 0.59, 95% CI - 0.31-1.49 cm, p = 0.195). VAS did not change in SMF, while it decreased in the sham group (between-group difference 0.27, 95% CI 0.04-0.50 cm/visit). Bone turnover markers remained stable. Conclusions: SMF as used in this investigation is not recommended for pain relief in postmenopausal women with vertebral deformity. The finding on long-term pain relief may relate to unbalanced randomization