Silicon solar cells are operating close to the theoretical maximum efficiency limit. To increase their efficiency beyond this limit, it is necessary to decrease energy losses occurring for ...high-energy photons. A sensitizing layer of singlet-fission material can in principle double the current generated by high-energy photons, and significantly reduce energy losses from high-energy photons within the solar cell. Here, we construct a model of such a solar cell, using Si(111) surfaces and tetracene. To increase the energy transfer between the two layers, a series of tetracene derivatives was synthesized, and the molecules were covalently attached onto the silicon surface as a seed layer. Using X-ray diffraction, a shift in crystal structure and ordering of the tetracene close to the seed layer can be observed. Unfortunately, the effect on the energy transfer was limited, showing a need for further investigations into the effect of the seed layer.
The amygdala is critically involved in emotional processing, including fear responses, and shows hyperactivity in anxiety disorders. Previous research in healthy participants has indicated that ...amygdala activity is down-regulated by cognitively demanding tasks that engage the PFC. It is unknown, however, if such an acute down-regulation of amygdala activity might correlate with reduced fear in anxious participants. In an fMRI study of 43 participants (11 men) with fear of snakes, we found reduced amygdala activity when visual stimuli were processed under high cognitive load, irrespective of whether the stimuli were of neutral or phobic content. Furthermore, dynamic causal modeling revealed that this general reduction in amygdala activity was partially mediated by a load-dependent increase in dorsolateral PFC activity. Importantly, high cognitive load also resulted in an acute decrease in perceived phobic fear while viewing the fearful stimuli. In conclusion, our data indicate that a cognitively demanding task results in a top–down regulation of amygdala activity and an acute reduction of fear in phobic participants. These findings may inspire the development of novel psychological intervention approaches aimed at reducing fear in anxiety disorders.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Biologists have observed that the presence of divalent metal is essential for the binding of the hormone oxytocin (OT) to its cellular receptor. However, this interaction is not understood on the ...molecular level. Because conformation is a key factor controlling ligand binding in biomolecule systems, we have used ion mobility experiments and molecular modeling to probe the conformation of the oxytocin−zinc complex. Results show that Zn2+ occupies an octahedral site in the interior of the OT peptide that frees the N-terminus and creates a structured hydrophobic binding site on the peptide exterior; both factors are conducive to binding oxytocin to its receptor.
CdSe nanocrystals (NCs) can be used as an electron acceptor in solar cells, employing organic ligands to passivate their surface and make them processable from solution. The nature and abundance of ...impurities present after NC ligand exchange from oleic acid to n‐butylamine are identified. A further purification step using hexane as a selective solvent is described, which excludes NC aggregates from solution. The influence of NC aggregates on photovoltaic device performance is studied in a CdSe:poly2‐methoxy‐5‐(3′,7′‐dimethyloctyloxy)‐1,4‐phenylene vinylene (MDMO‐PPV) bulk heterojunction solar cell. The exclusion of NC aggregates leads to a four‐fold increase in device power conversion efficiency (PCE) in optimized devices. A superior blend morphology leading to improved charge generation and a better NC percolation network is identified as the main causes of this increased solar cell performance.
The influence of nanocrystal aggregates on photovoltaic device
performance is studied in a CdSe:poly2‐methoxy‐5‐(3′,7′‐dimethyloctyloxy)‐1,4‐phenylene vinylene (MDMO‐PPV) bulk heterojunction solar cell. The exclusion of CdSe aggregates yields a superior blend morphology leading to improved charge generation and better percolation in the nanocrystal component. Solar cells with treated nanocrystals show a significant increase in device performance.
The combination of inorganic PbS quantum dots (QDs) and lead halide perovskite in one nanocomposite is considered as a promising approach to overcoming the limitations of metastable perovskites. ...However, to date, only a few examples of improved optoelectronic perovskites are realized with such materials. One of the keys to unraveling the full potential offered by the PbS QDs/perovskite material is the ability to purposefully modulate the interfacial electronic energy levels by changing the PbS QDs capping shell. Herein, this approach to adjust the offsets of the energy levels of the perovskite is demonstrated. To prepare the perovskite films with embedded PbS QDs, the organic capping of QDs is exchanged by a halide perovskite shell. Film properties are correlated to the structural changes of the soft perovskite matrix and their optical properties. Interestingly, this approach can be used to adjust the energy levels in the whole nanocomposite film, without changing the original bandgap, and thus paves the way for novel functional materials for optoelectronic devices. The applicability of this method is exemplified by fabricating solar cells with the perovskite nanocomposite, observing that the introduction of PbS/FAPI QDs into FAPI matrix boosts the average performance from 17.9% to 18.9% (21.3% champion device).
The study has demonstrated the impact of shell on the PbS quantum dot and subsequent structural and optoelectronic properties of FAPbI3 and MAPbI3 perovskite. It has been highlighted how the FAPbI3 shell is needed to obtain the favourable energy alignment and high efficiency solar cells. This work opens the door to the property tuning by the use of tailored shells.
In a strategy to identify novel genes involved in glioma pathogenesis by molecular characterization of chromosomal translocation breakpoints, we identified the KIAA1797 gene, encoding a protein with ...an as yet undefined function, to be disrupted by a 7;9 translocation in a primary glioblastoma culture. Array-based comparative genomic hybridization detected deletions involving KIAA1797 in around half of glioblastoma cell lines and glioblastomas investigated. Quantification of messenger RNA levels in human tissues demonstrated highest KIAA1797 expression in brain, reduced levels in all glioblastoma cell lines and most glioblastomas and similar levels in glial and neuronal cells by analysis of different hippocampal regions from murine brain. Antibodies against KIAA1797 were generated and showed similar protein levels in cortex and subcortical white matter of human brain, while levels were significantly reduced in glioblastomas with KIAA1797 deletion. By immunofluorescence of astrocytoma cells, KIAA1797 co-localized with vinculin in focal adhesions. Physical interaction between KIAA1797 and vinculin was demonstrated via co-immunoprecipitation. Functional in vitro assays demonstrated a significant decrease in colony formation, migration and invasion capacity of LN18 and U87MG glioma cells carrying a homozygous KIAA1797 deletion ectopically expressing KIAA1797 compared with mock-transduced cells. In an in vivo orthotopic xenograft mouse model, U87MG tumour lesions expressing KIAA1797 had a significantly reduced volume compared to tumours not expressing KIAA1797. In summary, the frequently deleted KIAA1797 gene encodes a novel focal adhesion complex protein with tumour suppressor function in gliomas, which we name 'focadhesin'. Since KIAA1797 genetic variation has been implicated in Alzheimer's disease, our data are also relevant for neurodegeneration.
The performance of quantum dots (QDs) in optoelectronic devices suffers as a result of sub-bandgap states induced by the large fraction of atoms on the surface of QDs. Recent progress in passivating ...these surface states with thiol ligands and halide ions has led to competitive efficiencies. Here, we apply a hybrid ligand mixture to passivate PbSe QD sub-bandgap tail states via a low-temperature, solid-state ligand exchange. We show that this ligand mixture allows tuning of the energy levels and the physical QD size in the solid state during film formation. We hereby present a novel, postsynthetic path to tune the properties of QD films.
Objective:
To evaluate the efficacy, tolerance and acceptability of UrgoStart Contact (Laboratoires Urgo), a new wound dressing impregnated with NOSF, as an MMP regulator in the management of ...neuropathic diabetic foot ulcers.
Method:
A multicentre, pilot, prospective, non-controlled open-label clinical trial. Adult patients with type 1 or 2 diabetes mellitus, who had a grade 1A (Texas classification), uninfected, neuropathic foot ulcer, 1–15cm2 in size and of 1–20 months' duration (mean 6.7±5.2 months) were included in the study. The primary endpoint was the relative reduction of the wound surface area (%) at the end of the study. Secondary endpoints included rate of complete healing, and tolerability and acceptability of the dressing. The wound dressing was changed regularly at the investigator's discretion, in accordance with the wound status and exudate level. Patients were followed up every 2 weeks for a 12-week period. At each visit, patients underwent clinical assessments, and ulcer surface area was measured by planimetry and photographs.
Results:
Thirty-four diabetic patients with a neuropathic foot ulcer were included but only 33 cases were analysed, as data were completely lost for one patient. At baseline, mean surface area was 2.7±2.4cm2. At the 12-week follow-up, the median surface area reduction was 82.7% (mean reduction 62.7±49.9%) and in 10 of the 33 analysed patients (30%) the wound was healed. Only two of the seven documented local adverse events were deemed to be dressing related. According to the nursing staff, acceptability was considered very satisfactory, particularly in term of conformability and ease of use.
Conclusion:
This pilot study indicates that use of the new UrgoStart Contact dressing, combined with offloading and debridement,may help promote the healing process of the neuropathic diabetic foot ulcers, and was well tolerated and accepted.
Declaration of interest:
This study was supported by grants from Laboratoires URGO pharmaceutical company. S. Bohbot is an employee of Laboratoires URGO; J.L. Richard has received monetary compensation as a consultant and speaker for Laboratoires URGO. Data management and statistical analysis were carried out by StatMed (Villemoirieu, France).
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