A comprehensive morphological study was used to elucidate chloride’s role in CH3NH3PbI3–x Cl x film evolution on a conducting polymer, PEDOT:PSS. Complex ion equilibria and aggregation in solution, ...as well as the role they play in nucleation, are found to ultimately be responsible for the unique morphological diversity observed in perovskite films grown in the presence of the chloride ion. An intermediate phase that is generated upon deposition and initial annealing templates continued self-assembly in the case of CH3NH3PbI3–x Cl x . In the absence of chloride, the film growth of CH3NH3PbI3 is directed by substrate interfacial energy. By employing the through-plane TEM analysis, we gain detailed insight into the unique crystallographic textures, grain structures, and elemental distributions across the breadth of films grown from precursor solutions with different chemistries. The lattice coherence seen in morphologies generated under the influence of chloride provides a physical rational for the enhancement in carrier diffusion length and lifetime.
Rationale
Previous research demonstrating that lysergic acid diethylamide (LSD) produces alterations in time perception has implications for its impact on conscious states and a range of ...psychological functions that necessitate precise interval timing. However, interpretation of this research is hindered by methodological limitations and an inability to dissociate direct neurochemical effects on interval timing from indirect effects attributable to altered states of consciousness.
Methods
We conducted a randomised, double-blind, placebo-controlled study contrasting oral administration of placebo with three microdoses of LSD (5, 10, and 20 μg) in older adults. Subjective drug effects were regularly recorded and interval timing was assessed using a temporal reproduction task spanning subsecond and suprasecond intervals.
Results
LSD conditions were not associated with any robust changes in self-report indices of perception, mentation, or concentration. LSD reliably produced over-reproduction of temporal intervals of 2000 ms and longer with these effects most pronounced in the 10 μg dose condition. Hierarchical regression analyses indicated that LSD-mediated over-reproduction was independent of marginal differences in self-reported drug effects across conditions.
Conclusions
These results suggest that microdose LSD produces temporal dilation of suprasecond intervals in the absence of subjective alterations of consciousness.
Twitter has become an important platform for geo-spatial analyses, providing high-volume spatial data on a wide variety of social processes. Understanding the relationship between population density ...and Twitter activity is therefore of key importance. This study reports a systematic relationship between population density and Twitter use. Number of tweets, number of users and population per unit area are related by power law functions with exponents greater than one. These relations are consistent with each other and hold across a range of spatial scales. This implies that population density can accurately predict Twitter activity, but importantly, it also implies that correct predictions are not given by a naive linear scaling analysis. The observed super-linearity has implications for any spatial analyses performed with Twitter data and is important for understanding the relationship between Twitter use and demographics. For example, the robustness of this relationship means that we can identify 'anomalous' geographic areas that deviate from the observed trend, identifying several towns with high/low usage relative to expectation; using the scaling relationship we are able to show that these anomalies are not caused by age structure, as has been previously proposed. Proper consideration of this scaling relationship will improve robustness in future geo-spatial studies using Twitter.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Question and answer (Q&A) websites are a medium where people can communicate and help each other. Stack Overflow is one of the most popular Q&A websites about programming, where millions of ...developers seek help or provide valuable assistance. Activity on the Stack Overflow website is moderated by the user community, utilizing a voting system to promote high quality content. The website was created on 2008 and has accumulated a large amount of crowd wisdom about the software development industry. Here we analyse this data to examine trends in the grouping of technologies and their users into different sub-communities. In our work we analysed all questions, answers, votes and tags from Stack Overflow between 2008 and 2020. We generated a series of user-technology interaction graphs and applied community detection algorithms to identify the biggest user communities for each year, to examine which technologies those communities incorporate, how they are interconnected and how they evolve through time. The biggest and most persistent communities were related to web development. In general, there is little movement between communities; users tend to either stay within the same community or not acquire any score at all. Community evolution reveals the popularity of different programming languages and frameworks on Stack Overflow over time. These findings give insight into the user community on Stack Overflow and reveal long-term trends on the software development industry.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
An effective method to control the rate of perovskite crystallization by incorporating rationally chosen additives into the perovskite precursor solutions is demonstrated. The processing additives ...simultaneously facilitate nucleation and modulate the kinetics of crystal growth during crystallization, leading to much smoother perovskite morphology with improved coverage area and crystal uniformity. As a result, it enables very high PCE (∼12%) planar‐heterojunction solar cells to be fabricated through the low‐temperature solution processes (under 150 °C). This study opens up a new direction for optimizing perovskite active layer properties to expand device performance ceilings.
The CO2 dry reforming of various types of waste plastics (LDPE, HDPE, PS, PET, and PP) and a simulated mixture of the different waste plastics was investigated over a Ni–Co–Al catalyst using a ...two-stage reactor. The first stage pyrolyzed the plastics, and the second stage involved catalytic-dry reforming of the product pyrolysis gases with CO2. The introduction of CO2 without a catalyst markedly increased the dry reforming reaction and significantly improved the production of H2/CO synthesis gas (syngas). The introduction of the Ni–Co–Al catalyst further significantly improved the production of syngas. LDPE produced the highest yield of syngas at 154.7 mmolsyngas g–1 plastic from the pyrolysis-catalytic-dry reforming process. The order of syngas production for the different plastics was LDPE < HDPE < PP < PS < PET. The syngas yield from the processing of the simulated waste plastic mixture was 148.6 7 mmolsyngas g–1 plastic which reflected the high content of the linear polyalkene plastics (LDPE, HDPE, PP) in the simulated waste plastic mixture.
An effective approach to significantly increase the electrical conductivity of a NiOx hole‐transporting layer (HTL) to achieve high‐efficiency planar heterojunction perovskite solar cells is ...demonstrated. Perovskite solar cells based on using Cu‐doped NiOx HTL show a remarkably improved power conversion efficiency up to 15.40% due to the improved electrical conductivity and enhanced perovskite film quality. General applicability of Cu‐doped NiOx to larger bandgap perovskites is also demonstrated in this study.
The addition of plastics to the steam pyrolysis/gasification of wood sawdust with and without a Ni/Al2O3 catalyst was investigated in order to increase the production of hydrogen in the gaseous ...stream. To study the influence of the biomass/plastic ratio in the initial feedstock, 5, 10 and 20 wt.% of polypropylene was introduced with the wood in the pyrolysis reactor. To investigate the effect of plastic type, a blend of 80 wt.% of biomass and 20 wt.% of either polypropylene, high density polyethylene, polystyrene or a mixture of real world plastics was fed into the reactor. The results showed that a higher gas yield (56.9 wt.%) and a higher hydrogen concentration and production (36.1 vol.% and 10.98 mmol H2 g−1 sample, respectively) were obtained in the gaseous fraction when 20 wt.% of polypropylene was mixed with the biomass. This significant improvement in gas and hydrogen yield was attributed to synergetic effects between intermediate species generated via co-pyrolysis. The Ni/Al2O3 catalyst dramatically improved the gas yield as well as the hydrogen concentration and production due to the enhancement of water gas shift and steam reforming reactions. Very low amounts of coke (less than 1 wt.% in all cases) were formed on the catalyst during reaction, with the deposited carbonaceous material being of the filamentous type. The Ni/Al2O3 catalyst was shown to be effective for hydrogen production in the co-pyrolysis/gasification process of wood sawdust and plastics.
Display omitted
•H2 has been produced from the pyrolysis/gasification of plastics/biomass mixtures.•Adding plastic to biomass increases H2 content with synergetic interaction.•Polypropylene addition produces higher H2 yield compared to polystyrene.•Addition of Ni/Al2O3 catalyst dramatically improved gas and H2 yield.
This paper investigates the co-production of hydrogen and carbon nanotubes from the pyrolysis–catalytic gasification of waste plastics (polypropylene). We report on the influence of a range of metal ...additions to a nickel based catalyst based on ternary mixed oxide types Ni–Metal–Al, where the metal was Zn, Mg, Ca, Ce or Mn. The results showed that of the different metal–nickel catalysts investigated, the Ni–Mn–Al catalyst was the most promising catalyst in relation to the co-production of hydrogen and CNT. For example, the Ni–Mn–Al catalyst produced 71.4mmolhydrogeng−1 plastic, while the hydrogen production using Ni–Ca–Al, Ni–Ce–Al and Ni–Zn–Al catalysts were 68.5mmolg−1, 63.1mmolg−1 and 45.9mmolhydrogeng−1 plastic respectively. In addition, carbon deposition on the catalyst was highest in the order of: Ni–Mn–Al>Ni–Ca–Al>Ni–Zn–Al>Ni–Ce–Al>Ni–Mg–Al. The carbon deposition for the Ni–Mn–Al catalyst was found to consist of mostly carbon nanotubes. Further investigation of the Ni–Mn–Al catalyst demonstrated that the interaction between Ni and catalyst support plays a significant role in the gasification process; weak metal support interaction (for the Ni–Mn–Al catalyst calcined at 300°C) resulted in a lower hydrogen production and much higher yield of carbon products. In addition, the influence of steam injection rate on hydrogen and carbon nanotube production was investigated for the Ni–Mn–Al catalyst. Increasing the steam injection rate significantly increased hydrogen production and decreased carbon deposition. However, at lower steam injection rates, the quality of the product carbon nanotubes was improved.
Display omitted
•Multi-walled carbon nanotubes (CNTs) and hydrogen are produced from waste plastic.•Mn addition to a Ni–Al catalyst produced large yields of CNTs and good yields of H2.•Steam significantly increases H2 production and decreases CNT yield.•Optimum steam injection can improve CNT quality.
Colorectal tumours that are wild type for KRAS are often sensitive to EGFR blockade, but almost always develop resistance within several months of initiating therapy. The mechanisms underlying this ...acquired resistance to anti-EGFR antibodies are largely unknown. This situation is in marked contrast to that of small-molecule targeted agents, such as inhibitors of ABL, EGFR, BRAF and MEK, in which mutations in the genes encoding the protein targets render the tumours resistant to the effects of the drugs. The simplest hypothesis to account for the development of resistance to EGFR blockade is that rare cells with KRAS mutations pre-exist at low levels in tumours with ostensibly wild-type KRAS genes. Although this hypothesis would seem readily testable, there is no evidence in pre-clinical models to support it, nor is there data from patients. To test this hypothesis, we determined whether mutant KRAS DNA could be detected in the circulation of 28 patients receiving monotherapy with panitumumab, a therapeutic anti-EGFR antibody. We found that 9 out of 24 (38%) patients whose tumours were initially KRAS wild type developed detectable mutations in KRAS in their sera, three of which developed multiple different KRAS mutations. The appearance of these mutations was very consistent, generally occurring between 5 and 6 months following treatment. Mathematical modelling indicated that the mutations were present in expanded subclones before the initiation of panitumumab treatment. These results suggest that the emergence of KRAS mutations is a mediator of acquired resistance to EGFR blockade and that these mutations can be detected in a non-invasive manner. They explain why solid tumours develop resistance to targeted therapies in a highly reproducible fashion.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
PDF
