Oxygen binding to cobalt and iron phthalocyanines as determined from in situ X-ray absorption spectroscopy

Cobalt phthalocyanine (CoPc) and iron phthalocyanine (FePc) are possible oxygen reduction catalysts in fuel cells, but the exact functioning and deactivation of these catalysts is unknown. The electronic structure of the CoPc and FePc has been studied in situ under hydrogen and oxygen atmospheres by a combination of ambient-pressure X-ray photoelectron spectroscopy and X-ray absorption spectroscopy. The results show that when oxygen is introduced, the iron changes oxidation state while the cobalt does not. The data show that oxygen binds in an end-on configuration in CoPc, while for FePc side-on binding is most likely

CropPol: a dynamic, open and global database on crop pollination

Seventy five percent of the world's food crops benefit from insect pollination. Hence, there has been increased interest in how global change drivers impact this critical ecosystem service. Because standardized data on crop pollination are rarely available, we are limited in our capacity to understand the variation in pollination benefits to crop yield, as well as to anticipate changes in this service, develop predictions, and inform management actions. Here, we present CropPol, a dynamic, open and global database on crop pollination. It contains measurements recorded from 202 crop studies, covering 3,394 field observations, 2,552 yield measurements (i.e. berry weight, number of fruits and kg per hectare, among others), and 47,752 insect records from 48 commercial crops distributed around the globe. CropPol comprises 32 of the 87 leading global crops and commodities that are pollinator dependent. Malus domestica is the most represented crop (32 studies), followed by Brassica napus (22 studies), Vaccinium corymbosum (13 studies), and Citrullus lanatus (12 studies). The most abundant pollinator guilds recorded are honey bees (34.22% counts), bumblebees (19.19%), flies other than Syrphidae and Bombyliidae (13.18%), other wild bees (13.13%), beetles (10.97%), Syrphidae (4.87%), and Bombyliidae (0.05%). Locations comprise 34 countries distributed among Europe (76 studies), Northern America (60), Latin America and the Caribbean (29), Asia (20), Oceania (10), and Africa (7). Sampling spans three decades and is concentrated on 2001-05 (21 studies), 2006-10 (40), 2011-15 (88), and 2016-20 (50). This is the most comprehensive open global data set on measurements of crop flower visitors, crop pollinators and pollination to date, and we encourage researchers to add more datasets to this database in the future. This data set is released for non-commercial use only. Credits should be given to this paper (i.e., proper citation), and the products generated with this database should be shared under the same license terms (CC BY-NC-SA). This article is protected by copyright. All rights reserved

Temperature-Dependent 1s2p Resonant Inelastic X-ray Scattering of CoO

The temperature-dependent 1s2p resonant inelastic X-ray scattering (RIXS) spectra of CoO have been measured with 0.3 eV overall resolution, and the RIXS planes have been analyzed with multiplet calculations. The analysis of the high-resolution 1s2p RIXS plane allows a more detailed determination of the ground-state electronic structure, as compared to Is X-ray absorption spectroscopy (XAS). The apparent absence of interference effects suggests that the lifetime broadening of the pre-edge states is (significantly) reduced from the edge lifetime broadening. The temperature-dependent RIXS planes are explained as a combination of the ground state and first excited state due to thermal population of the excited state, which are a result of the symmetry distortion, 3d spin orbit coupling, and magnetic exchange interactions. No features due to charge transfer and nonlocal transitions are observed due to the relatively small cobalt oxygen overlap as compared to higher valent systems. The successful determination of the spin state and crystal field parameters using hard X-ray experiments promises to make 1s2p RIXS a useful technique for in situ transition metal oxide studies

Origin of Low Energy d-d Excitations Observed on Wet Chemically Prepared Cobalt Bearing Nanoparticles by 2p3d Resonant X-ray Emission Spectroscopy

The 2p3d resonant X-ray emission spectroscopic (RXES) measurements on 8.4 and 5.0 nm cobalt and 3.6 nm cobalt-nickel nanoparticles coated with oleate molecules are provided. The spectra reveal low energy resonant Raman features at 0.3 and 0.75 ev. In combination with time-dependent density functional theory (TD-DFT) and ligand field multiple (LFM) calculations, these are ascribed to d-d excitations of cobalt ions in a low symmetry ligand field. Two different chemical environments of the ion may cause the transitions. In the first model cobalt ions in the nanoparticle outer atomic layer, resulting from the adsorbate binding, cause the excitations. These are transitions from a mixture of B-4(1g) plus E-4(g) to E-4(g) at 0.3 eV. At 0.75 ev transitions to B-4(2g) and (4)A(1g) take place. In the alternative model the excitations occur in a cobalt molecular species that might coexist with the nanoparticles. Here the transitions are from (4)A(2g) to E-4(g) and to E-4(g) plus B-4(2g) at 0.3 and 0.75 eV, respectively. On the basis of two-dimensional 2p3d RXES planes of the models and the differences between the three different nanoparticle systems, we exclude the first model and conclude that the metallic particles indeed coexist with varying minor degrees of molecular species. We observe however a second type of cobalt species, which is possible related to surface-ligated cobalt ions

In-situ Scanning Transmission X-Ray Microscopy of Catalytic Solids and Related Nanomaterials

The present status of in-situ scanning transmission X-ray microscopy (STXM) is reviewed, with an emphasis on the abilities of the STXM technique in comparison with electron microscopy. The experimental aspects and interpretation of X-ray absorption spectroscopy (XAS) are briefly introduced and the experimental boundary conditions that determine the potential applications for in-situ XAS and in-situ STXM studies are discussed. Nanoscale chemical imaging of catalysts under working conditions is outlined using cobalt and iron Fischer-Tropsch catalysts as showcases. In the discussion, we critically compare STXM-XAS and STEM-EELS (scanning transmission electron microscopy-electron energy loss spectroscopy) measurements and indicate some future directions of in-situ nanoscale imaging of catalytic solids and related nanomaterials

In-situ Scanning Transmission X-Ray Microscopy of Catalytic Solids and Related Nanomaterials

The present status of in-situ scanning transmission X-ray microscopy (STXM) is reviewed, with an emphasis on the abilities of the STXM technique in comparison with electron microscopy. The experimental aspects and interpretation of X-ray absorption spectroscopy (XAS) are briefly introduced and the experimental boundary conditions that determine the potential applications for in-situ XAS and in-situ STXM studies are discussed. Nanoscale chemical imaging of catalysts under working conditions is outlined using cobalt and iron Fischer-Tropsch catalysts as showcases. In the discussion, we critically compare STXM-XAS and STEM-EELS (scanning transmission electron microscopy-electron energy loss spectroscopy) measurements and indicate some future directions of in-situ nanoscale imaging of catalytic solids and related nanomaterials

The TalkMeHome service for people with early dementia

INTRODUCTION: People suffering from mild dementia may get lost during a walk, which can be dangerous for them and may add to the anxiety felt by their informal caregivers. TalkMeHome is a new service that allows these people to get home safely in such situations using their mobile phone. With an emergency button they can call a remote care professional who will guide the lost person home. To accomplish this, the professional caregiver is able to follow the person’s GPS-location on a map and in Google Streetview. This paper reports on the gathering of user requirements, the technical design of the TalkMeHome service, and small scale experiments to assess the effectiveness and user experience of the service. AIMS AND OBJECTIVES: The goal of the evaluation of the TalkMeHome service was to assess the effectiveness of this novel service and to investigate how persons with mild dementia and care professionals experience the service. The final aim is to make the TalkMeHome service structurally available for the target group. METHODS: User requirements were collected through desk research, expert interviews with care professionals, and pre-experiments by researchers in which conventional trackers were used combined with an additional mobile phone to simulate the anticipated implementation as close as possible. In the small scale experiments four participants with mild dementia were included using inclusion criteria based on the target group. Each participant was accompanied outdoor by two researchers, one observing the participant, the other ensuring the participant’s safety regarding traffic. The actual test began by pushing the alarm button, simulating being ‘lost’. This established a connection with the care professional who then started guiding the participant back home. Data were collected by observation, interviews with the participants, and questionnaires and interviews with the care professionals. RESULTS: As for effectiveness, all four participants were guided home satisfactorily, technical imperfections set aside. Only a few easily corrected mistakes were noticed. The evaluations further showed that guiding people with dementia home is possible even under suboptimal conditions (unreliable information of the person with dementia, missing location updates or an incomplete map). Regarding the experiences of the users, both persons with dementia and care professionals, we conclude that the contact between both was easy but guiding somebody home is a demanding task for a care professional. CONCLUSIONS: The results suggest that TalkMeHome is an effective service, which increases our confidence that it can be made available as a commercial service. It also shows that a technology that is not 100% accurate can still provide an added value. In terms of user experience, our work revealed the difficulty of the care professional’s task. With an aging population the demand for appropriate support will increase. For this reason the research group ‘ICT-Innovations in Healthcare’ will take the initiative for a ‘Skills Lab’, a laboratory equipped with the necessary hardware and software to facilitate both research and training with regard to the skills of a care professional offering remote services to patients