Solid-State Oxidation of Alcohols in Gold-Coated Milling Vessels via Direct Mechanocatalysis.

This paper presents a novel approach for the selective oxidation of alcohols to their corresponding aldehydes through direct mechanocatalysis, employing a gold-coated milling vessel as catalyst and air as the oxidation agent. By adjusting milling frequency, media, and duration, high catalytic efficiencies and selectivities are achieved. Remarkably, yields of up to 99 % are obtained for specific substrates, with a turnover number (TON) of 8200 and a turnover frequency (TOF) of 0.77 s-1, surpassing existing alternatives. Confirmation of the catalytic reaction indeed occurring on the milling tool surface was achieved through X-ray photoelectron spectroscopy (XPS).

Milling Medium-Free Suzuki Coupling by Direct Mechanocatalysis: From Mixer Mills to Resonant Acoustic Mixers.

Here we describe the development of a sustainable and cost-effective approach for catalytic cross-coupling reactions in mechanochemistry. It is found that the substrate's impact with the vessel wall alone is sufficient to initiate the reaction, thus indicating that milling balls function primarily as a mixing agent for direct mechanocatalytic Suzuki coupling. The absence of milling balls can be offset by adjusting the rheology using liquid-assisted grinding (LAG). The LAG sweet spot of 0.25 µL mg-1 is confirmed for both resonance acoustic mixers (RAMs) and ball-free mixer mills, and is higher than in the presence of milling balls. RAMs exhibit excellent performance in the Suzuki reaction, achieving yields of 90 % after 60 min and complete conversion after 90 min. The longevity of the milling vessel is significantly improved in a RAM, allowing for at least 20 reactions without deterioration.

From Inert to Catalytically Active Milling Media: Galvanostatic Coating for Direct Mechanocatalysis.

The inert milling balls, commonly utilized in mechanochemical reactions, were coated with a layer of Pd and utilized as catalyst in the direct mechanocatalytic Suzuki reaction. With high yields (>80 %), the milling balls can be recycled multiple times in the absence of any solvents, ligands, catalyst-molecules and -powders, while utilizing as little as 0.8 mg of Pd per coated milling ball. The coating sequence, the support material, and the layer thickness were examined towards archiving high catalyst retention, low abrasion and high conversion. The approach was transferred to the coating of milling vessels revealing the interplay between catalytically available surface area and the mechanical energy impact in direct mechanocatalysis.

The Direct Mechanocatalytic Suzuki-Miyaura Reaction of Small Organic Molecules.

The molecular Suzuki cross-coupling reaction was conducted mechanochemically, without solvents, ligands, or catalyst powders. Utilizing one catalytically active palladium milling ball, products could be formed in quantitative yield in as little as 30 min. In contrast to previous reports, the adjustment of milling parameters led to the complete elimination of abrasion from the catalyst ball, thus enabling the first reported systematic catalyst analysis. XPS, in situ XRD, and reference experiments provided evidence that the milling ball surface was the location of the catalysis, allowing a mechanism to be proposed. The versatility of the approach was demonstrated by extending the substrate scope to deactivated and even sterically hindered aryl iodides and bromides.

Humans, machines, and double standards? The moral evaluation of the actions of autonomous vehicles, anthropomorphized autonomous vehicles, and human drivers in road-accident dilemmas.

A more critical evaluation of the actions of autonomous vehicles in comparison to those of human drivers in accident scenarios may complicate the introduction of autonomous vehicles into daily traffic. In two experiments, we tested whether the evaluation of actions in road-accident scenarios differs as a function of whether the actions were performed by human drivers or autonomous vehicles. Participants judged how morally adequate they found the actions of a non-anthropomorphized autonomous vehicle (Experiments 1 and 2), an anthropomorphized autonomous vehicle (Experiment 2), and a human driver (Experiments 1 and 2) in otherwise identical road-accident scenarios. The more lives were spared, the better the action was evaluated irrespective of the agent. However, regardless of the specific action that was chosen, the actions of the human driver were always considered more morally justifiable than the corresponding actions of the autonomous vehicle. The differences in the moral evaluations between the human driver and the autonomous vehicle were reduced, albeit not completely eliminated, when the autonomous vehicle was anthropomorphized (Experiment 2). Anthropomorphizing autonomous vehicles may thus influence the processes underlying moral judgments about the actions of autonomous vehicles such that the actions of anthropomorphized autonomous vehicles appear closer in moral justifiability to the actions of humans. The observed differences in the moral evaluation of the actions of human drivers and autonomous vehicles could cause a more critical public response to accidents involving autonomous vehicles compared to those involving human drivers which might be reduced by anthropomorphizing the autonomous vehicles.

Self-protective and self-sacrificing preferences of pedestrians and passengers in moral dilemmas involving autonomous vehicles.

Upon the introduction of autonomous vehicles into daily traffic, it becomes increasingly likely that autonomous vehicles become involved in accident scenarios in which decisions have to be made about how to distribute harm among involved parties. In four experiments, participants made moral decisions from the perspective of a passenger, a pedestrian, or an observer. The results show that the preferred action of an autonomous vehicle strongly depends on perspective. Participants' judgments reflect self-protective tendencies even when utilitarian motives clearly favor one of the available options. However, with an increasing number of lives at stake, utilitarian preferences increased. In a fifth experiment, we tested whether these results were tainted by social desirability but this was not the case. Overall, the results confirm that strong differences exist among passengers, pedestrians, and observers about the preferred course of action in critical incidents. It is therefore important that the actions of autonomous vehicles are not only oriented towards the needs of their passengers, but also take the interests of other road users into account. Even though utilitarian motives cannot fully reconcile the conflicting interests of passengers and pedestrians, there seem to be some moral preferences that a majority of the participants agree upon regardless of their perspective, including the utilitarian preference to save several other lives over one's own.

Do they really wash their hands? Prevalence estimates for personal hygiene behaviour during the COVID-19 pandemic based on indirect questions.

BACKGROUND: During the COVID-19 pandemic, billions of people have to change their behaviours to slow down the spreading of the virus. Protective measures include self-isolation, social (physical) distancing and compliance with personal hygiene rules, particularly regular and thorough hand washing. Prevalence estimates for the compliance with the COVID-19 measures are often based on direct self-reports. However, during a health crisis there is strong public pressure to comply with health and safety regulations so that people's responding in direct self-reports may be seriously compromised by social desirability. METHODS: In an online survey, an indirect questioning technique was used to test whether the prevalence of hygiene practices may be lower than in conventional surveys when confidentiality of responding is guaranteed. The Extended Crosswise Model is an indirect questioning technique that guarantees the confidentiality of responding. To the degree that direct self-reports are biased by social desirability, prevalence estimates of hygiene practices such as thorough hand washing based on the Extended Crosswise Model should be lower than those based on direct self-reports. RESULTS: We analysed data of 1434 participants. In the direct questioning group 94.5% of the participants claimed to practice proper hand hygiene; in the indirect questioning group a significantly lower estimate of only 78.1% was observed. CONCLUSIONS: These results indicate that estimates of the degree of commitment to measures designed to counter the spread of the disease may be significantly inflated by social desirability in direct self-reports. Indirect questioning techniques with higher levels of confidentiality seem helpful in obtaining more realistic estimates of the degree to which people follow the recommended personal hygiene measures. More realistic estimates of compliance can help to inform and to adjust public information campaigns on COVID-19 hygiene recommendations.