Publications

Collision induced unfolding is method used with ion mobility mass spectrometry to examine protein structures and their stability. Such experiments yield information about higher order protein structures, yet are unable to provide details about the underlying processes. That information can however be provided using molecular dynamics simulations. Here, we investigate the collision induced unfolding of norovirus capsid dimers from the Norwalk and Kawasaki strains by employing molecular dynamics simulations over a range of temperatures, representing different levels of activation. The dimers have highly similar structures, but the activation reveals differences in the dynamics that arises in response to the activation.

High-quality crystals of CoTeO₄ were grown by application of chemical vapor transport reactions in closed silica ampoules, starting from polycrystalline material in a temperature gradient 640 °C → 580 °C with TeCl₄ as transport agent. Crystal structure analysis of CoTeO₄ from single crystal X-ray data revealed a dirutile-type structure with Co^II and Te^VI atoms at crystallographically distinct sites, each with point group symmetry . The statistical significance and accuracy of the previously reported structural model based on powder data with the ordered arrangement of Co and Te cations was noticeably improved. CoTeO₄ does not undergo a structural phase transition upon heating, but decomposes stepwise (Co₂Te₃O₈ as intermediate phase) to Co₃TeO₆ as the only crystalline phase stable above 770 °C. Temperature-dependent magnetic susceptibility and dielectric measurements suggest antiferromagnetic ordering at ∼50 K. Optical absorption spectroscopy and computational studies reveal wide-band semiconductive behavior for CoTeO₄. The experimentally determined band gap of ∼2.42 eV is also found for CdS, which is frequently used in photovoltaic systems but is hazardous to the environment. Hence, CoTeO₄ might be a possible candidate to replace CdS in this regard.

The synthetic availability of mol­ecular water oxidation catalysts containing high-valent ions of 3d metals in the active site is a prerequisite to enabling photo- and electrochemical water splitting on a large scale. Herein, the synthesis and crystal structure of di­ammonium {μ-1,3,4,7,8,10,12,13,16,17,19,22-dodeca­aza­tetra­cyclo­[8.8.4.13,17.18,12]tetra­cosane-5,6,14,15,20,21-hexa­onato}ferrate(IV) acetic acid tris­olvate, (NH4)2[FeIV(C12H12N12O6)]·3CH3COOH or (NH4)2[FeIV(L–6H)]·3CH3COOH is reported. The FeIV ion is encapsulated by the macropolycyclic ligand, which can be described as a dodeca-aza-quadricyclic cage with two capping tri­aza­cyclo­hexane fragments making three five- and six six-membered alternating chelate rings with the central FeIV ion. The local coord­ination environment of FeIV is formed by six deprotonated hydrazide nitro­gen atoms, which stabilize the unusual oxidation state. The FeIV ion lies on a twofold rotation axis (multiplicity 4, Wyckoff letter e) of the space group C2/c. Its coordination geometry is inter­mediate between a trigonal prism (distortion angle φ = 0°) and an anti­prism (φ = 60°) with φ = 31.1°. The Fe—N bond lengths lie in the range 1.9376 (13)–1.9617 (13) Å, as expected for tetra­valent iron. Structure analysis revealed that three acetic acid mol­ecules additionally co-crystallize per one iron(IV) complex, and one of them is positionally disordered over four positions. In the crystal structure, the ammonium cations, complex dianions and acetic acid mol­ecules are inter­connected by an intricate system of hydrogen bonds, mainly via the oxamide oxygen atoms acting as acceptors.

The present study investigates the photofragmentation behavior of iodine-enhanced nitroimidazole-based radiosensitizer model compounds in their protonated form using near-edge X-ray absorption mass spectrometry and quantum mechanical calculations. These molecules possess dual functionality: improved photoabsorption capabilities and the ability to generate species that are relevant to cancer sensitization upon photofragmentation. Four samples were investigated by scanning the generated fragments in the energy regions around C 1s, N 1s, O 1s, and I 3d-edges with a particular focus on NO2+ production. The experimental summed ion yield spectra are explained using the theoretical near-edge X-ray absorption fine structure spectrum based on density functional theory. Born-Oppenheimer-based molecular dynamics simulations were performed to investigate the fragmentation processes.

U(VI) in natural pyromorphite reaches 0.5 wt%. However, this depends on concentration of U in source solutions and the upper limit of incorporation of uranyl into pyromorphite at low temperature is unknown. If U(VI) incorporation capacity in the structure is high enough, Pb-apatite could be used in radioactive waste remediation. In this study, eight compounds were synthesized from aqueous solutions containing Pb²⁺, (UO₂)²⁺, (PO₄)^3- and Cl^- ions in a still water column under ambient conditions. In each synthesis, the molar ratio of (UO₂)²⁺:Pb was varied, targeting composition Pb_5-x(UO₂)_x(PO₄)₃Cl. The final solutions were analyzed with inductively coupled plasma optical emission spectroscopy (ICP-OES) for Pb and U(VI) concentrations, while dried solids were analyzed using powder X-ray diffraction (PXRD), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), wavelength dispersive X-ray spectroscopy (WDS) using an electron microprobe, and Raman spectroscopy. Synthesis products are synthetic analogs of pyromorphite containing (UO₂)²⁺, partially substituting Pb²⁺. For the higher initial concentration of U, coprecipitation of a second phase/phases was observed. U was removed from the solution at levels ranging from 74.3 % (σ = 1.5) to 88 % (σ = 2), and Pb was removed at levels ranging from 91 % (σ = 2) to 96.8 % (σ = 1.9). Precipitation of pyromorphite from uranyl-contaminated solutions may immobilize uranyl in the form of highly insoluble, stable, crystalline Pb phosphates.

Stoichiometric Ti_0.33-xAl_xB_0.67 coatings with x = 0.04, 0.15, 0.21, and 0.28 were synthesized by magnetron sputtering and characterized regarding phase formation, mechanical properties, and oxidation behavior. By increasing the Al concentration from 4 to 28 at.%, the measured elastic modulus (496±19 GPa) and unit cell volume (25.646 ų ) decreased by 33 and 0.8 %, respectively. The Al concentration induced changes in measured elastic modulus and unit cell volume are in very good agreement with ab initio predictions, as the maximum deviations between experiment and theory, observed here, are 12 and 1.1 %, respectively. The corresponding hardness values decreased by 45 % from 22±1 to 12±1 GPa. The oxidation experiments were performed in ambient air at 700, 800, and 900 °C for 1, 4, and 8 h. Analysis by scanning transmission electron microscopy (STEM) revealed a bimodal, strongly Al concentration-dependent oxidation behavior where films containing ≤15 at.% of Al form a porous, non-passivating crystalline oxide scale containing Ti -rich as well as Al -rich oxide regions, while the formation of a passivating, dense, X-ray amorphous oxide scale was observed for films containing ≥ 21 at.% of Al. Coincident with the passive scale formation for Al concentrations ≥ 21 at.%, the elastic modulus decreases by ≥ 32.6 % compared to TiB₂ and can be rationalized based on Al concentration induced bond weakening as revealed by the concomitant cohesive energy reduction of ≥ 22 %.

Two new cyanido-bridged {Fe^IIM^II} double chains were obtained by reacting cyanido anions [M(CN)₄]²⁻ with complex cations [Fe^II(tptz)]²⁺ (preformed in situ by mixing a hydrated tetrafluoroborate salt of iron(II) and a tptz ligand, tptz = 2,4,6-tri(2-pyridyl)-1,3,5-triazine) having the general formula [Fe^II(tptz)M^II(CN)₄]·2H₂O·CH₃CN, where M = Pd (1) or Pt (2). Additionally, two molecular complexes formulated as [Fe^II(tptz)₂][M^II(CN)₄]·4.25H₂O, where M = Pd (3) or Pt (4), were subsequently obtained from the same reaction, as secondary products. Single crystal X-ray analysis revealed that 1 and 2 are isostructural and crystallize in the P-1 triclinic space group. Their structure consists of a double-chain with a ladder-like topology, in which cyanido-based [M(CN)₄]²⁻ metalloligands coordinate, through three CN⁻ ligands and three [Fe^II(tptz)]²⁺ complex cations. Compounds 3 and 4 are also isostructural and crystallize in the P triclinic space group, and the X-ray structural data show the formation of [Fe^II(tptz)₂]²⁺ and [M^II(CN)₄]²⁻ ionic units interconnected through H-bonds and π⋯π stacking supramolecular interactions. The static DC magnetic measurements recorded in the temperature range of 2–300 K showed that 1 and 2 exhibit incomplete spin transition on cooling, which is also confirmed by single crystal XRD analysis and Mössbauer spectroscopy. Compounds 3 and 4 are diamagnetic, most likely due to the encapsulation of Fe(II) in a tight pocket formed by two tptz ligands that preserve the low-spin state in the temperature range of 2–400 K.

The work in this dissertation is devoted to investigating order and interfaces in epitaxial heterostructures. To achieve that the software tool box GenL was developed for simulating and fitting x-ray diffraction patterns from epitaxial thin films, which is used to access structural information on the length scales of interfaces and atomic bonds. Employing GenL, it is shown that a small lattice mismatch between substrate and epitaxial layer is not the sole origin of high crystal quality, as demonstrated for nearly strain-free epitaxial growth of tungsten on sapphire with a lattice mismatch of up to 19.4 %. Furthermore, it is discussed that electronic states at the substrate/film interface can have substantial significance for the crystal structure of an epitaxial layer. For instance, despite a nearly mismatch-free interface of body-centered cubic iron on spinel, the presence of a boundary-induced interface layer with tetragonally distorted crystal structure is discovered, which has a profound impact on the magnetic properties. Finally, when creating multilayered structures, not only the interface states but the total structure is found to influence the physical properties, which is demonstrated for the interlayer exchange coupling in [Fe/MgO]_Nsuperlattices.

Note: This PhD thesis is partly based on the licentiate dissertation "Growth of high quality Fe thin films" by Anna L. Ravensburg, Uppsala University, 2022. Particularly parts of: Chapter 1, Sections 2.0, 2.1, 2.2, 3.0, 3.1, 3.2, 3.3, 5.1, and Fig. 2.6 are adapted from the licentiate thesis with minor edits and updates.

Four new compositionally complex perovskites with multiple (four or more) cations on the B site of the perovskites have been studied. The materials have the general formula La_0.5Sr_2.5(M)₂O_7−δ (M = Ti, Mn, Fe, Co, and Ni) and have been synthesized via conventional solid-state synthesis. The compounds are the first reported examples of compositionally complex n = 2 Ruddlesden–Popper perovskites. The structure and properties of the materials have been determined using powder X-ray diffraction, neutron diffraction, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and magnetometry. The materials are isostructural and adopt the archetypal I4/mmm space group with the following unit cell parameters: a ∼ 3.84 Å, and c ∼ 20.1 Å. The measured compositions from energy dispersive X-ray spectroscopy were La_0.51(2)Sr_2.57(7)Ti_0.41(2)Mn_0.41(2)Fe_0.39(2)Co_0.38(1)Ni_0.34(1)O_7−δ, La_0.59(4)Sr_2.29(23)Mn_0.58(5)Fe_0.56(6)Co_0.55(6)Ni_0.42(4)O_7−δ, La_0.54(2)Sr_2.49(13)Mn_0.41(2)Fe_0.81(5)Co_0.39(3)Ni_0.36(3)O_7−δ, and La_0.53(4)Sr_2.55(19)Mn_0.67(6)Fe_0.64(5)Co_0.31(2)Ni_0.30(3)O_7−δ. No magnetic contribution is observed in the neutron diffraction data, and magnetometry indicates a spin glass transition at low temperatures.

Temperature-dependent dc-magnetization and ac-susceptibility curves have been recorded for series of single and double layered Ruddlesden-Popper multicomponent perovskites with chemical formula A₂BO₄ and A₃B₂O₇, respectively, with (La, Sr) on A-sites and up to 7 different cations on the B-sites (Ti, Cr, Mn, Fe, Co, Ni, Cu). The phase purity and chemical homogeneity of the compounds were investigated by X-ray diffraction and energy dispersive X-ray spectroscopy. Independently of the composition, spin glassiness is observed in both systems. Scaling analyses suggest the materials undergo spin glass phase transitions at low temperatures. Yet, qualitative differences are observed between the single-layered and double-layered systems, which are discussed in the light of the spatial dimensionality and magnetic interaction in layered oxide perovskites.

Heavy-fermion metals are prototype systems for observing emergent quantum phases driven by electronic interactions1-6. A long-standing aspiration is the dimensional reduction of these materials to exert control over their quantum phases7-11, which remains a significant challenge because traditional intermetallic heavy-fermion compounds have three-dimensional atomic and electronic structures. Here we report comprehensive thermodynamic and spectroscopic evidence of an antiferromagnetically ordered heavy-fermion ground state in CeSiI, an intermetallic comprising two-dimensional (2D) metallic sheets held together by weak interlayer van der Waals (vdW) interactions. Owing to its vdW nature, CeSiI has a quasi-2D electronic structure, and we can control its physical dimension through exfoliation. The emergence of coherent hybridization of f and conduction electrons at low temperature is supported by the temperature evolution of angle-resolved photoemission and scanning tunnelling spectra near the Fermi level and by heat capacity measurements. Electrical transport measurements on few-layer flakes reveal heavy-fermion behaviour and magnetic order down to the ultra-thin regime. Our work establishes CeSiI and related materials as a unique platform for studying dimensionally confined heavy fermions in bulk crystals and employing 2D device fabrication techniques and vdW heterostructures12 to manipulate the interplay between Kondo screening, magnetic order and proximity effects.

Innovations in resistive switching devices constitute a core objective for the development of ultralow-power computing devices. Forming-free resistive switching is a type of resistive switching that eliminates the need for an initial high voltage for the formation of conductive filaments and offers promising opportunities to overcome the limitations of traditional resistive switching devices. Here, we demonstrate mixed charge state oxygen vacancy-engineered electroforming-free resistive switching in NiFe₂O₄ (NFO) thin films, fabricated as asymmetric Ti/NFO/Pt heterostructures, for the first time. Using pulsed laser deposition in a controlled oxygen atmosphere, we tune the oxygen vacancies together with the cationic valence state in the nickel ferrite phase, with the latter directly affecting the charge state of the oxygen vacancies. The structural integrity and chemical composition of the films are confirmed by X-ray diffraction and hard X-ray photoelectron spectroscopy, respectively. Electrical transport studies reveal that resistive switching characteristics in the films can be significantly altered by tuning the amount and charge state of the oxygen vacancy concentration during the deposition of the films. The resistive switching mechanism is seen to depend upon the migration of both singly and doubly charged oxygen vacancies formed as a result of changes in the nickel valence state and the consequent formation/rupture of conducting filaments in the switching layer. This is supported by the existence of an optimum oxygen vacancy concentration for efficient low-voltage resistive switching, below or above which the switching process is inhibited. Along with the filamentary switching mechanism, the Ti top electrode also enhances the resistive switching performance due to interfacial effects. Time-resolved measurements on the devices display both long- and short-term potentiation in the optimized vacancy-engineered NFO resistive switches, ideal for solid-state synapses achieved in a single system. Our work on correlated oxide forming-free resistive switches holds significant potential for CMOS-compatible low-power, nonvolatile resistive memory and neuromorphic circuits.

Bone strength is an important contributor to fracture risk. Areal bone mineral density (aBMD) derived from dual-energy X-ray absorptiometry (DXA) is used as a surrogate for bone strength in fracture risk prediction tools. 3D finite element (FE) models predict bone strength better than aBMD, but their clinical use is limited by the need for 3D computed tomography and lack of automation. We have earlier developed amethod to reconstruct the 3D hip anatomy froma 2D DXA image, followed by subject-specific FE-based prediction of proximal femoral strength. In the current study, we aim to evaluate the method's ability to predict incident hip fractures in a populationbased cohort (Osteoporotic Fractures in Men [MrOS] Sweden). We defined two subcohorts: (i) hip fracture cases and controls cohort: 120men with a hip fracture (<10 years frombaseline) and two controls to each hip fracture case, matched by age, height, and body mass index; and (ii) fallers cohort: 86men who had fallen the year before their hip DXA scan was acquired, 15 of which sustained a hip fracture during the following 10 years. For each participant, we reconstructed the 3D hip anatomy and predicted proximal femoral strength in 10 sideways fall configurations using FE analysis. The FE-predicted proximal femoral strength was a better predictor of incident hip fractures than aBMD for both hip fracture cases and controls (difference in area under the receiver operating characteristics curve, Delta AUROC = 0.06) and fallers (Delta AUROC = 0.22) cohorts. This is the first time that FE models outperformed aBMD in predicting incident hip fractures in a population-based prospectively followed cohort based on 3D FE models obtained from a 2D DXA scan. Our approach has potential to notably improve the accuracy of fracture risk predictions in a clinically feasible manner (only one single DXA image is needed) and without additional costs compared to the current clinical approach.

Many enzymes use adaptive frameworks to preorganize substrates,accommodate various structural and electronic demands of intermediates,and accelerate related catalysis. Inspired by biological systems,a Ru-based molecular water oxidation catalyst containing a configurationallylabile ligand [2,2 ':6 ',2 ''-terpyridine]-6,6 ''-disulfonatewas designed to mimic enzymatic framework, in which the sulfonatecoordination is highly flexible and functions as both an electrondonor to stabilize high-valent Ru and a proton acceptor to acceleratewater dissociation, thus boosting the catalytic water oxidation performancethermodynamically and kinetically. The combination of single-crystalX-ray analysis, various temperature NMR, electrochemical techniques,and DFT calculations was utilized to investigate the fundamental roleof the self-adaptive ligand, demonstrating that the on-demand configurationalchanges give rise to fast catalytic kinetics with a turnover frequency(TOF) over 2000 s(-1), which is compared to oxygen-evolvingcomplex (OEC) in natural photosynthesis.

One novel option for treating metastatic castration resistant prostate cancer is radionuclide therapy targeting prostate-specific membrane antigen (PSMA), e.g. [Lu-177]Lu-PSMA-617. Overexpression of HER2 has been found in 80% of metastatic cases of prostate cancer. Previous research showed that HER2 is elevated post irradiation in PC-3 prostate cancer cells. Co-treating with anti-HER2 antibody Trastuzumab gave less proliferation of irradiated tumor cells in vitro, and when using radionuclide therapy, also in vivo. The aim of this study is to determine whether the same holds true in PSMA-expressing PC-3 PIP cells using [Lu-177]Lu-PSMA-617 radionuclide therapy. PC-3 PIP and 22Rv1 prostate cancer cells were tested in vitro, treated with 6 Gy of x-rays with or without Trastuzumab incubation. We measured uptake of HER2-targeting affibody [Ga-68]Ga-ABY-025 and cell survival, e.g. using the WST-1 assay. Three groups (n=10 each) of male nude Balb/c mice were inoculated with PC-3 PIP xenograft tumors and treated with just [Lu-177]Lu-PSMA-617 (20 MBq), [Lu-177]Lu-PSMA-617 (20 MBq) and Trastuzumab (4 x 5 mg/kg), or left untreated. Tumor sizes and animal survival was observed. In vitro, x-ray irradiation did reduce survival in 22Rv1 but not PC-3 PIP cells, and there was no significant effect of Trastuzumab treatment. Cells expressed HER2 but not significantly elevated post irradiation. In vivo, mice co-treated with Trastuzumab had significantly longer survival than untreated mice, but not than only [Lu-177]Lu-PSMA-617. Staining of tumor sections showed similar HER2 and PSMA expression across groups. In conclusion, these results give no support for any benefit from co-treatment with anti-HER2 antibody for PSMA-targeted radioligand therapy.

Metal centers in transition metal–ligand complexes occur in a variety of oxidation states causing their redox activity and therefore making them relevant for applications in physics and chemistry. The electronic state of these complexes can be studied by X-ray absorption spectroscopy, which is, however, due to the complex spectral signature not always straightforward. Here, we study the electronic structure of gas-phase cationic manganese acetylacetonate complexes Mn(acac)_1–3⁺ using X-ray absorption spectroscopy at the metal center and ligand constituents. The spectra are well reproduced by multiconfigurational wave function theory, time-dependent density functional theory as well as parameterized crystal field and charge transfer multiplet simulations. This enables us to get detailed insights into the electronic structure of ground-state Mn(acac)_1–3⁺ and extract empirical parameters such as crystal field strength and exchange coupling from X-ray excitation at both the metal and ligand sites. By comparison to X-ray absorption spectra of neutral, solvated Mn(acac)_2,3 complexes, we also show that the effect of coordination on the L₃ excitation energy, routinely used to identify oxidation states, can contribute about 40–50% to the observed shift, which for the current study is 1.9 eV per oxidation state.

Most of the physical, mechanical, and esthetic properties of wood products are affected by the drying of sawn timber. A better understanding of moisture transport in wood during kiln drying is necessary to obtain better quality products, shorter drying schedules, lower energy consumption, and a more sustainable process. Four-dimensional X-ray computed tomography (4DCT) (three-dimensional in space and one in time) with image processing techniques can be used to study the moisture content (MC) of sawn timber during kiln drying. The development of the technique is however made difficult by computational complexity and a lack of accurate experimental validation. In this study, a method relying on 4DCT has been developed using state-of-the-art image processing techniques. The method was validated by a regression analysis of the predicted MC against gravimetric measurements for different timber cross sections and differentinitial MC distributions on a significantly smaller scale than has previously been investigated. It is concluded that the MC can be estimated with an average uncertainty of ±4.8 percentage points on a 10 mm scale. Sawmills could ultimately benefit from a better understanding of wood-water interactions and dry sawn timber more efficiently.

One of the reasons for the high efficiency and selectivity of biological catalysts arise from their ability to control the pathways of substrates and products using protein channels, and by modulating the transport in the channels using the interaction with the protein residues and the water/hydrogen-bonding network. This process is clearly demonstrated in Photosystem II (PS II), where its light-driven water oxidation reaction catalyzed by the Mn4CaO5 cluster occurs deep inside the protein complex and thus requires the transport of two water molecules to and four protons from the metal center to the bulk water. Based on the recent advances in structural studies of PS II from X-ray crystallography and cryo-electron microscopy, in this review we compare the channels that have been proposed to facilitate this mass transport in cyanobacteria, red and green algae, diatoms, and higher plants. The three major channels (O1, O4, and Cl1 channels) are present in all species investigated; however, some differences exist in the reported structures that arise from the different composition and arrangement of membrane extrinsic subunits between the species. Among the three channels, the Cl1 channel, including the proton gate, is the most conserved among all photosynthetic species. We also found at least one branch for the O1 channel in all organisms, extending all the way from Ca/O1 via the ‘water wheel’ to the lumen. However, the extending path after the water wheel varies between most species. The O4 channel is, like the Cl1 channel, highly conserved among all species while having different orientations at the end of the path near the bulk. The comparison suggests that the previously proposed functionality of the channels in T. vestitus (Ibrahim et al., Proc Natl Acad Sci USA 117:12624-12635, 2020; Hussein et al., Nat Commun 12:6531, 2021) is conserved through the species, i.e. the O1-like channel is used for substrate water intake, and the tighter Cl1 and O4 channels for proton release. The comparison does not eliminate the potential role of O4 channel as a water intake channel. However, the highly ordered hydrogen-bonded water wire connected to the Mn4CaO5 cluster via the O4 may strongly suggest that it functions in proton release, especially during the S-0 -> S-1 transition (Saito et al., Nat Commun 6:8488, 2015; Kern et al., Nature 563:421-425, 2018; Ibrahim et al., Proc Natl Acad Sci USA 117:12624-12635, 2020; Sakashita et al., Phys Chem Chem Phys 22:15831-15841, 2020; Hussein et al., Nat Commun 12:6531, 2021).

This project investigates how different types of perovskite solar cells, differentiated by choice of materials and processing techniques, compares to each other regarding performance and characterization. The purpose of the project is to further develop perovskite solar cells and to improve the method of manufacturing for better performance.

A total of 160 perovskite solar cells are constructed, divided into eight distinct types. Two different perovskites, MAPbI₃ and MAFAPbI₃, are used and prepared using two different solvents: isopropanol (IPA) and pentanol (PenOH). Furthermore half of the solar cells contain phenethylammonium iodide (PEAI). When completed, the solar cells' performances are measured and compared. Lastly, the solar cells and the perovskites are compared through characterization measurements. An incident-photon-to-current-efficiency (IPCE) spectroscopy is performed on the solar cells to get a better understanding of the efficiency depending on the wavelength of the incident light. An UV-vis-NIR spectroscopy is performed on the thin film to analyze the absorbance and determine the band gap of the material. The pre-crystallized perovskite powders are compared through characterization measurements, such as X-ray Photoelectron Spectroscopy (XPS) characterization and scanning electron microscopy (SEM) measurements. This results in comparing material compositions and optical properties of the solar cells.

The results indicate that MAPbI₃ (PenOH) is the highest performing type independent of the presence of PEAI. The measured mean power conversion efficiency (PCE) are 15.47% and 13.84% for MAPbI₃ (PenOH) with and without PEAI respectively. The best performing individual solar cell contains MAPbI₃ (PenOH) with PEAI and has a PCE of 20.21%. On the contrary, MAFAPbI₃ (PenOH) with and without PEAI perform the worst. The best improvement of the PCE after two weeks is +22.13%, given by MAPbI₃ (PenOH) with PEAI. Generally, solar cells with MAPbI₃ have a larger band gap, 1.61 eV, compared to MAFAPbI₃'s 1.55 eV, regardless of the presence of PEAI. MAPbI₃ (PenOH) can convert a larger portion of incident photons to electrical energy, up to almost 80%. MAFAPbI₃ (IPA) converts almost as much, over 70%, while MAPbI₃ (IPA) and MAFAPbI₃ (PenOH) in some measurements barely has a 50% conversion rate.

Photochemistry and photophysics processes involve structures far from equilibrium. In these reactions, there is often strong coupling between nuclear and electronic degrees of freedom. For first-row transition metals, K beta X-ray emission spectroscopy (XES) is a sensitive probe of electronic structure due to the direct overlap between the valence orbitals and the 3p hole in the final state. Here the sensitivity of K beta mainline (K beta(1,3)) XES to structural dynamics is analyzed by simulating spectral changes along the excited state dynamics of an iron photosensitizer [Fe-II(bmip)(2)](2+) [bmip = 2,6-bis(3-methyl-imidazole-1-ylidine)-pyridine], using both restricted active space (RAS) multiconfigurational wavefunction theory and a one-electron orbital-energy approach in density-functional theory (1-DFT). Both methods predict a spectral blue-shift with increasing metal-ligand distance, which changes the emission intensity for any given detection energy. These results support the suggestion that the [Fe-II(bmip)(2)](2+) femtosecond K beta XES signal shows oscillations due to coherent wavepacket dynamics. Based on the RAS results, the sensitivity to structural dynamics is twice as high for K beta compared to K alpha, with the drawback of a lower signal-to-noise ratio. K beta sensitivity is favored by a larger spectral blue-shift with increasing metal-ligand distance and larger changes in spectral shape. Comparing the two simulations methods, 1-DFT predicts smaller energy shifts and lower sensitivity, likely due to missing final-state effects. The simulations can be used to design and interpret XES probes of non-equilibrium structures to gain mechanistic insights in photocatalysis.

Laboratory column experiments have been used to study the sequential removal of nitrate (NO₃⁻) and sulfate (SO₄²⁻) from mine water, where NO₃⁻ was removed through denitrification and SO₄²⁻ was removed through SO₄²⁻ reduction and the subsequent precipitation of hydrogen sulfide (H₂S) in a hematite-coated biochar (HCB) bioreactor. Denitrification and SO₄²⁻ reduction were investigated in columns filled with pine woodchips and pine woodchips + biochar, both with and without the addition of lactate. Experimental results indicated that a >90% NO₃⁻ removal from 50 mg L⁻¹ NO₃⁻-N was achieved at a hydraulic residence time of 5 days without lactate addition, but that SO₄²⁻ reduction was minimal after an initial startup period. Lactate was added to stimulate SO₄²⁻ reduction, producing H₂S with >90% SO₄²⁻ removal from an initial concentration of 361 mg L⁻¹ SO₄²⁻-S. Sulfate concentrations were reduced to a greater extent in the woodchip + biochar column, and NH₄⁺ production was enhanced in both columns after lactate addition. After treatment in the HCB columns, H₂S and NH₄⁺ were removed to >95%. X-ray photoelectron spectroscopy (XPS) indicated that S²⁻, S₂²⁻, S⁰ and NH₄⁺ were accumulating in the HCB columns and surface-bound iron was converted from Fe(III) to Fe(II). The XPS results suggested that the reductive dissolution of hematite preceded the precipitation of H₂S as FeS, pyrite and elemental sulfur on the HCB surfaces.

The solvation capacity of dispersion solvents plays a crucial role in the solution processing of metal halide perovskites. For instance, N,N-dimethylformamide (DMF), a widely used dispersion solvent, possesses high solvation capacity but often generates suboptimal film quality due to slow crystallization kinetics. We propose using low-solvation binary cosolvents (nitrile-and ether-type solvents) to achieve a balance between solvation (i.e., sufficient solubility of precursors) and desolvation (i.e., rapid crystallization of films) pro-cesses during perovskite synthesis. The polarity and hydrogen -bonding property of these cosolvents synergistically enhance their solvation capacity, facilitating perovskite precursor dissolution. Moreover, the low-solvation cosolvents accelerate the crystalliza-tion of well-defined intermediate films, yielding higher-quality pe-rovskites than those synthesized with DMF. The optimized modules achieved an active-area efficiency of 22.27%, with a certified aper-ture-area efficiency of 16.10% and corresponding active-area effi-ciency of 20.75%. This research on solvation regulation provides universal guidelines for innovatively preparing high-quality halide perovskites.

Previously unknown Co-2(TeO3)(OH)(2) and Co-15(TeO3)(14)(OH)(2) were obtained under mild hydrothermal reaction conditions (210 degrees C, autogenous pressure) from alkaline solutions. Their crystal structures were determined from single-crystal X-ray diffraction data. Co-2(TeO3)(OH)(2) (Z = 2, P1 over bar , a = 5.8898(5), b = 5.9508(5), c = 6.8168(5) & ANGS;, alpha = 101.539(2), beta = 100.036(2), gamma = 104.347(2)& DEG;, 2120 independent reflections, 79 parameters, R[F-2 > 2 sigma(F-2)] = 0.017) crystallizes in a unique structure comprised of undulating (2)(& PROP;)[Co-2(OH)(6/3)O3/3O2/2O1/1](4-) layers. Adjacent layers are linked by Te-IV atoms along the [001] stacking direction. Co-2(TeO3)(OH)(2) is stable up to 450 & DEG;C and decomposes under the release of water into Co6Te5O16 and CoO. Magnetic measurements of Co-2(TeO3)(OH)(2) showed antiferromagnetic ordering at & AP; 70 K. The crystal structure of Co-15(TeO3)(14)(OH)(2) (Z = 3, R3 over bar , a = 11.6453(2), c = 27.3540(5) & ANGS;, 3476 independent reflections, 112 parameters, R[F-2 > 2 sigma(F-2)] = 0.026) is isotypic with Co-15(TeO3)(14)F-2. A quantitative structural comparison revealed that the main structural difference between the two phases is connected with the replacement of F by OH, whereas the remaining part of the three-periodic network defined by [CoO6], [CoO5(OH)], [CoO5] and [TeO3] polyhedra is nearly unaffected. Consequently, the magnetic properties of the two phases are similar, namely being antiferromagnetic at low temperatures.

The Concise Guide to PHARMACOLOGY 2023/24 is the sixth in this series of biennial publications. The Concise Guide provides concise overviews, mostly in tabular format, of the key properties of approximately 1800 drug targets, and about 6000 interactions with about 3900 ligands. There is an emphasis on selective pharmacology (where available), plus links to the open access knowledgebase source of drug targets and their ligands (), which provides more detailed views of target and ligand properties. Although the Concise Guide constitutes almost 500 pages, the material presented is substantially reduced compared to information and links presented on the website. It provides a permanent, citable, point-in-time record that will survive database updates. The full contents of this section can be found at . G protein-coupled receptors are one of the six major pharmacological targets into which the Guide is divided, with the others being: ion channels, nuclear hormone receptors, catalytic receptors, enzymes and transporters. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. The landscape format of the Concise Guide is designed to facilitate comparison of related targets from material contemporary to mid-2023, and supersedes data presented in the 2021/22, 2019/20, 2017/18, 2015/16 and 2013/14 Concise Guides and previous Guides to Receptors and Channels. It is produced in close conjunction with the Nomenclature and Standards Committee of the International Union of Basic and Clinical Pharmacology (NC-IUPHAR), therefore, providing official IUPHAR classification and nomenclature for human drug targets, where appropriate.

We designed and investigated the electronic, mechanical, and thermoelectric properties of Graphene/hexagonal Boron Nitride (Gr/h-BN) heterostructure at various twisting angles based on the Ab-initio simulation. The structural stability was studied at optimized rotation angles (cp) = 0 degrees, 16.10 degrees, 21.79 degrees, 38.21 degrees, 43.90 degrees and 60 degrees. The heterostructure shows semiconducting nature at cp = 0 degrees, 21.79 degrees and 38.21 degrees. These twisted heterostructures have demonstrated extraordinary mechanical properties such as Young's modulus and bulk modulus. Using the semiclassical Boltzmann transport theory, it is observed that the Seebeck coefficient, electric conductivity, and power factor at cp = 0 degrees, 21.79 degrees, 38.21 degrees, and 60 degrees are much higher than the values measured at cp = 16.10 degrees and 43.90 degrees. Moreover, at cp = 60 degrees, the Power Factor for the n-type dopants can reach 1.37 x 1011 W/msK2. The lattice thermal conductivity at room temperature is found to be very low for cp = 16.10 degrees, 21.79 degrees, 43.90 degrees and 38.21 degrees rotation angles. An ultralow lattice thermal conductivity with a value of 0.095 W/mK at 300K has been observed for 21.79 degrees rotation angle, which is lower than other rotation angles because of very low group velocity (22.1 km/s) and short phonon lifetime (similar to 0.12 ps). The high thermoelectric performance results from an ultralow thermal conductivity arising due to the strong lattice anharmonicity. The present observations can offer significant impact on the design of high performance thermoelectric materials based on twisted van der Waals heterostructure (vdWH).

INTRODUCTION 

One of the main limiting factors to the life span of spinal implants is the release of detrimental ions and particles, which are typically produced by wear and corrosion1,2. One suggested approach to overcome these issues is the use of silicon nitride-based coatings on metallic implants because of their low wear rates and their ability to slowly dissolve in aqueous solutions into biocompatible ions only, which could be advantageous in terms of limiting the effects of wear debris and ion release3. A previous study found that alloying the silicon nitride coating with Fe and C did not have a negative effect on mechanical properties nor biocompatibility in a direct contact in vitro test4. However, the dissolution behaviour of the coatings remains to be investigated. Furthermore, due to the close proximity to nerve tissues in spinal implants, the effect of the ions released on the neural tissue is a concern. The present study aimed to study the dissolution behaviour and in vitro neural cell response of SiFeCN coatings. A combinatorial approach was used for efficient screening of different compositions. 

EXPERIMENTAL METHODS 

SiFeCN coatings were deposited on CoCr disc substrates by reactive sputtering in an in-house built equipment, allowing for combinatorial processes, using Si, Fe and C solid targets. Nitrogen was supplied as a reactive gas. The coatings were characterized in 9 points using x-ray photoelectron spectroscopy (XPS), vertical scanning interferometry (VSI) and scanning electron microscopy (SEM). The points were placed in a 3x3 grid with 22.5 mm between each point. 

The dissolution behaviour was evaluated by exposing the coated samples to cell media for 14 days. The obtained extracts were diluted (1:32, 1:48, 1:64 and 1:80 dilution) and used to measure ion levels with inductively coupled plasma (ICP-OES) and to assess indirect biocompatibility in vitro using the MTT assay and glial cells. 

RESULTS AND DISCUSSION 

The XPS results showed compositional gradients of Si ranging between 36.4-47.3 at.%, Fe 1.4-9.3 at.% and C 4.5-13.9 at.% with average surface roughness, Sa, of 7.4 to 11.1 nm, similar to SiN and CoCr reference materials. SEM after exposure displayed signs of dissolution with visibly increased porosity for the coated samples. The SiN reference also showed substantial changes to the surface. The ICP results (Figure 1) showed a reduction in Co ions from the substrate in the coated samples compared to uncoated. Moreover, the addition of Fe and C decreased the ion release from the coating compared to the SiN reference coating. Extract biocompatibility tests suggested that glial cells tolerated the extracts and their dilutions obtained from the coated samples in a dose- dependent manner and the cell viability was comparable to that of the uncoated CoCr and SiN coating. 

CONCLUSIONS 

The findings from this study suggest that using iron and carbon as alloying elements in silicon nitride coatings has the potential to reduce ion release from a metallic substrate and lower the dissolution rate of the coating, while having a comparable cell response to that of the CoCr and SiN control materials. Therefore, SiFeCN coatings merit further investigation as a future option for spinal implants. 

REFERENCES 

1.Shimamura Y. et al., Spine. 33(4):351–355, 2008 2.Vicars R. et al., Comprehensive Biomaterials II. (pp. 246–264), 20173. Pettersson M. et al., ACS Biomaterials Science and Engineering. 2(6):998–1004, 20164. Skjöldebrand C. et al., Materials (Basel). 13(9):1–16, 2020 

ACKNOWLEDGMENTS 

This project has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No 812765 and from the European Union’s Seventh Framework Programme (FP7/2007-2013), grant agreement GA-310477(LifeLongJoints). 

A series of heteroleptic Cu(I) diimine complexes with different ancillary ligands and 6,6'-dimethyl-2,2'-bipyridine-4,4'-dibenzoic acid (dbda) as the anchoring ligand were selfassembled on TiO2 surfaces and used as dyes for dye-sensitized solar cells (DSSCs). The binding to the TiO2 surface was studied by hard X-ray photoelectron spectroscopy for a brominecontaining complex, confirming the complex formation. The performance of all complexes was assessed and rationalized on the basis of their respective ancillary ligand. The DSSC photocurrent-voltage characteristics, incident photon-to-current conversion efficiency (IPCE) spectra, and calculated lowest unoccupied molecular orbital (LUMO) distributions collectively show a push-pull structural dye design, in which the ancillary ligand exhibits an electron-donating effect that can lead to improved solar cell performance. By analyzing the optical properties of the dyes and their solar cell performance, we can conclude that the presence of ancillary ligands with bulky substituents protects the Cu(I) metal center from solvent coordination constituting a critical factor in the design of efficient Cu(I)-based dyes. Moreover, we have identified some components in the I-/I-3(-)-based electrolyte that causes dissociation of the ancillary ligand, i.e., TiO2 photoelectrode bleaching. Finally, the detailed studies on one of the dyes revealed an electrolyte-dye interaction, leading to a dramatic change of the dye properties when adsorbed on the TiO2 surface.

A novel tetratopic metallo-linker, [Ru(tda)(py(PhCOOH)2)2], 1, (tda = 2,2′:6′,2′′-terpyridine-6,6′′-dicarboxylate; py(PhCOOH)2 = (4,4′-(pyridine-3,5-diyl)dibenzoic acid), that is structurally based on one of the most active molecular water oxidation catalysts has been prepared and fully characterized, including single crystal X-ray diffraction. 1 bears geometric similarities to H4TBAPy (H4TBAPy = 4,4′,4′′,4′′′-(pyrene-1,3,6,8-tetrayl)tetrabenzoic acid), i.e. the native linker in NU-1000, which offers the possibility to synthesize NU-1000-Ru mixed linker MOFs solvothermally. Mixed linker MOF formation was demonstrated by powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM), and Ru linker incorporation confirmed by FT-IR, energy-dispersive X-ray (EDX) spectroscopy and inductively coupled plasma optical emission spectroscopy (ICP-OES). It was found that the Ru contents in the final mixed linker MOFs correlate with the amount of Ru linker present during solvothermal synthesis, albeit not in a linear fashion. The cyclic voltammograms (CV) of the mixed linker MOFs are largely dominated by TBAPy-based oxidations with features attributed to 1. Interestingly, Ru linkers near the crystal surface are oxidized directly by interfacial hole transfer form the electrode, while those in the crystal interior can be oxidized indirectly from oxidized TBAPy linkers at more anodic potential. Upon repeated scanning, the CVs show the appearance of new waves that arise from irreversible TBAPy oxidation, as well as from the activation of the Ru-based water oxidation catalyst. Of the materials prepared, the one with the highest Ru content, NU-1000-Ruhigh, was shown to catalyze the electrochemical oxidation of water to dioxygen. The Faradaic efficiency (FE) of the construct is 37%, due to water oxidation being accompanied by oxidative transformations of the TBAPy linkers. Despite the low FE, NU-1000-Ruhigh is still among the best MOF-based water oxidation catalysts, operating by a unique co-linker mediated hole-transport mechanism to supply oxidizing equivalents also to catalysts in the crystal interior.

This study demonstrates the electrochemical sodiation and desodiation of gallium (Ga). A variety of techniques including galvanostatic cycling, cyclic voltammetry, as well as ex situ and in situ powder X-ray diffraction were used to determine the electrochemical reaction mechanisms. The sodiation and desodiation of Ga occurs reversibly at 0.71 V vs Na+/Na and the sodiated product was determined to be NaGa4 with a theoretical capacity of 96 mAh g(-1) (567 mAh cm(-3)). In addition, an anomalous plateau was observed at 0.66 V vs Na+/Na during the sodiation, which was attributed to a slow diffusion of Na into Ga particles. It was also shown that Na22Ga39 was not formed even if it is one of the expected compounds from the Ga-Na phases diagram. However, new crystalline structures were observed and were attributed to metastable phases of NaGa4.

A supermassive black hole, obscured by cosmic dust, powers the nearby active galaxy NGC 1068. Neutrinos, which rarely interact with matter, could provide information on the galaxy's active core. We searched for neutrino emission from astrophysical objects using data recorded with the IceCube neutrino detector between 2011 and 2020. The positions of 110 known gamma-ray sources were individually searched for neutrino detections above atmospheric and cosmic backgrounds. We found that NGC 1068 has an excess of 79(-20)(+22) neutrinos at tera-electron volt energies, with a global significance of 4.2 sigma, which we interpret as associated with the active galaxy. The flux of high-energy neutrinos that we measured from NGC 1068 is more than an order of magnitude higher than the upper limit on emissions of tera-electron volt gamma rays from this source.

Experimental near-edge x-ray-absorption fine-structure (NEXAFS) spectra of the nitrosonium NO+ ion are presented and theoretically analyzed. While neutral NO has an open shell, the cation is a closed-shell species, which for NEXAFS leads to the simplicity of a closed-shell spectrum. Compared to neutral NO, the electrons in the cation experience a stronger Coulomb potential, which introduces a shift of the ionization potential towards higher energies, a depletion of intensity in a large interval above the pi* resonance, and a shift of the sigma* resonance from the continuum to below the ionization threshold. NEXAFS features at the nitrogen and oxygen K edges of NO+ are compared, as well as NEXAFS features at the nitrogen edges of the isoelectronic closed-shell species NO+, N2, and N2H+.

The influence of changes induced by ion irradiation on structure and thermal stability of metastable cubic (Ti,Al)N coatings deposited by cathodic arc evaporation is systematically investigated by correlating experiments and theory. Decreasing the nitrogen deposition pressure from 5.0 to 0.5 Pa results in an ion flux-enhancement by a factor of three and an increase of the average ion energy from 15 to 30 eV, causing the stress-free lattice parameter to expand from 4.170 to 4.206 Å, while the chemical composition of Ti_0.27Al_0.21N_0.52 remains unchanged. The 0.9% lattice parameter increase is a consequence of formation of Frenkel pairs induced by ion bombardment, as revealed by density functional theory (DFT) simulations. The influence of the presence of Frenkel pairs on the thermal stability of metastable Ti_0.27Al_0.21N_0.52 is investigated by scanning transmission electron microscopy, differential scanning calorimetry, atom probe tomography and in-situ synchrotron X-ray powder diffraction. It is demonstrated that the ion flux and ion energy induced formation of Frenkel pairs increases the thermal stability as the Al diffusion enabled crystallization of the wurtzite solid solution is retarded. This can be rationalized by DFT predictions since the presence of Frenkel pairs increases the activation energy for Al diffusion by up to 142%. Hence, the thermal stability enhancement is caused by a hitherto unreported mechanism - the Frenkel pair impeded Al mobility and thereby retarded formation of wurtzite solid solution.

Sustainable sources of hydrogen are a vital component of the envisioned energy transition. Understanding and mimicking the [FeFe]-hydrogenase provides a route to achieving this goal. In this study we re-visit a molecular mimic of the hydrogenase, the propyl dithiolate bridged complex [Fe₂(μ-pdt)(CO)₄(CN)₂]²⁻, in which the cyanide ligands are tuned via Lewis acid interactions. This system provides a rare example of a cyanide containing [FeFe]-hydrogenase mimic capable of catalytic proton reduction, as demonstrated by cyclic voltammetry. EPR, FTIR, UV-vis and X-ray absorption spectroscopy are employed to characterize the species produced by protonation, and reduction or oxidation of the complex. The results reveal that biologically relevant iron-oxidation states can be generated, potentially including short-lived mixed valent Fe(I)Fe(II) species. We propose that catalysis is initiated by protonation of the diiron complex and the resulting di-ferrous bridging hydride species can subsequently follow two different pathways to promote H₂ gas formation depending on the applied reduction potential.

Full understanding of moisture transport in wood is not achieved despite many transport theories (Thybring et al. 2021). It remains an essential research domain to improve both timber quality and drying schedules. X-ray Computed Tomography (CT) has shown to be a useful tool in this regard as it allows for the computation of moisture-content (MC) at voxel level (Couceiro 2019). To the knowledge of the authors, no method exists to analyse the evolution of MC and gradient (MG) distributions, that can later be related to the quality of the sawn-timber. Popular methods, such as presented in Esping 1988, to quantify the MG are not adapted to CT (local) data as they provide averaged (global) MC and MG. In this study, an analysis method based on image-processing and CT data is presented to statistically quantify the evolution of MC and MG distributions within cross-sections of timber during drying.

The electrolyte solution of NaBOB in TEP is a low-cost, fluorine-free and flame-retardant electrolyte with ionic conductivity of 5 mS cm(-1), recently discovered to show promises for sodium-ion batteries. Here, the abilities of this electrolyte to effectively form a solid electrolyte interphase (SEI) was augmented with five common electrolyte additives of fluoroethylene carbonate (FEC), vinylene carbonate (VC), prop-1-ene-1,3-sultone (PES), 1,3,2-dioxathiolane 2,2-dioxide (DTD) and tris(trimethylsilyl)phosphite (TTSPi). Full-cells with electrodes of Prussian white and hard carbon and industrial mass loadings of >10 mg cm(-2) and electrolyte volumes of <5 ml g(-1) were used. X-ray photoelectron spectroscopy (XPS) and pressure analysis were also deployed to investigate parasitic reactions. Cells using electrolyte additives of PES, PES+DTD and PES+TTSPi (3 wt%) showed significantly increased performance in terms of capacity retention and initial Coulombic efficiency as compared to additive-free NaBOB-TEP. The best cell retained 80% discharge capacity (89 mAh g(-1)) after 450 cycles, which is also significantly better than reference cells using 1 M NaPF6 in EC:DEC electrolyte. This study sheds light on opportunities to optimize the NaBOB-TEP electrolyte for full-cell sodium-ion batteries in order to move from low-mass-loading lab-scale electrodes to high mass loading electrodes aiming for commercialization of sodium-ion batteries.

Postcollision-interaction (PCI) effects involving multistep decay processes following Ar 1s photoionization has been studied by Auger electron spectroscopy. The experiment focused on LMM Auger electrons measured in small photon energy steps across the Ar 1s photoionization threshold. Decay pathways that we studied include (1) the Ar+*2p-1 -> Ar2+3p-2 LMM alpha Auger process due to a single L hole created by KL fluorescence, (2) the Ar2+*2p-2 -> Ar3+*2p-13p-2 LMM1 Auger process following double L shell hole states produced by a KLL Auger processes, and (3) the subsequent Ar3+*2p-13p-2 -> Ar4+3p-4 LMM2 Auger transitions. Particularly pronounced PCI shifts and unusual line shapes compared to the ordinary one-step PCI process were found in the spectra of Auger processes following a KLL Auger first step. The experimental results were compared with calculations based on the semiclassical approach to PCI. Good agreement was found between the calculated and experimental PCI shifts. The result opens possibilities for further studies of the multielectron dynamics between Auger electrons mediated through the photoelectron in these and similar systems.

PANDA (anti-proton annihiliation at Darmstadt) is planned to be one of the four main experiments at the future international accelerator complex FAIR (Facility for Antiproton and Ion Research) in Darmstadt, Germany. It is going to address fundamental questions of hadron physics and quantum chromodynamics using cooled antiproton beams with a high intensity and and momenta between 1.5 and 15 GeV/c. PANDA is designed to reach a maximum luminosity of 2 × 10³² cm⁻² s. Most of the physics programs require an excellent particle identification (PID). The PID of hadronic states at the forward endcap of the target spectrometer will be done by a fast and compact Cherenkov detector that uses the detection of internally reflected Cherenkov light (DIRC) principle. It is designed to cover the polar angle range from 5° to 22° and to provide a separation power for the separation of charged pions and kaons up to 3 standard deviations (s.d.) for particle momenta up to 4 GeV/c in order to cover the important particle phase space. This document describes the technical design and the expected performance of the novel PANDA disc DIRC detector that has not been used in any other high energy physics experiment before. The performance has been studied with Monte-Carlo simulations and various beam tests at DESY and CERN. The final design meets all PANDA requirements and guarantees sufficient safety margins.

On 22 September 2017, IceCube reported a high-energy neutrino event which was found to be coincident with a flaring blazar, TXS 0506+056. This multi-messenger observation hinted at blazars contributing to the observed high-energy astrophysical neutrinos and raised a need for extensive correlation studies. Recent work shows that the internal absorption of gamma rays, and their interactions intrinsic to the source and with the extragalactic background, will cause a lack of energetic gamma-ray and neutrino correlation while hinting towards a correlation between neutrinos and lower photon energy observations in the X-ray and radio bands. Studies based on published IceCube alerts and radio observations report a possible radio-neutrino correlation in both gamma-ray bright and gamma-ray dim active galactic nuclei (AGN). However, they have marginal statistical significance due to limited available data. We present a correlation analysis between 15 GHz radio observations of AGN reported in the MOJAVE XV catalog and 10 years of IceCube detector data and discuss the results derived from a time-averaged stacking analysis.

Context. The Gaia-ESO Survey (GES) is a public, high-resolution spectroscopic survey, conducted with the multi-object spectrograph Fibre Large Array Multi Element Spectrograph (FLAMES) on the Very Large Telescope (European Southern Observatory, ESO, Cerro Paranal, Chile) from December 2011 to January 2018. Gaia-ESO has targeted all the main stellar components of the Milky Way, including thin and thick disc, bulge, and halo. In particular, a large sample of open clusters has been observed, from very young ones, just out of the embedded phase, to very old ones. Aims. The different kinds of clusters and stars targeted in them are useful to reach the main science goals of the open cluster part of GES, which are the study of the open cluster structure and dynamics, the use of open clusters to constrain and improve stellar evolution models, and the definition of Galactic disc properties (e.g., metallicity distribution). Methods. The Gaia-ESO Survey is organised in 19 working groups (WGs), each one being responsible for a task. We describe here the work of three of them, one in charge of the selection of the targets within each cluster or association (WG4), one responsible for defining the most probable candidate member stars (WG1), and another one in charge of the preparation of the observations (WG6). As the entire GES has been conducted before the second Gaia data release, we could not make use of the Gaia astrometry to define cluster member candidates. We made use of public and private photometry to select the stars to be observed with FLAMES, once brought on a common astrometric system (the one defined by 2MASS). Candidate target selection was based on ground-based proper motions, radial velocities, and X-ray properties when appropriate, for example, and it was mostly used to define the position of the clusters' evolutionary sequences in the colour-magnitude diagrams. Targets for GIRAFFE were then selected near the sequences in an unbiased way. We used known information on membership, when available, only for the few stars to be observed with UVES. Results. We collected spectra for 62 confirmed clusters in the main observing campaign (and a few more clusters were taken from the ESO archive). Among them are very young clusters, where the main targets are pre-main sequence stars, clusters with very hot and massive stars currently on the main sequence, intermediate-age and old clusters where evolved stars are the main targets. Our strategy of making the selection of targets as inclusive and unbiased as possible and of observing a significant and representative fraction of all possible targets permitted us to collect the largest, most accurate, and most homogeneous spectroscopic data set on open star clusters ever achieved.

Two 2D Hofmann-type complexes of the composition [Fe(Phpz)₂{M(CN)₂}₂] (where Phpz = 2-phenylpyrazine; M = Ag, Au) have been synthesized, and their spin-crossover (SCO) behavior has been thoroughly characterized. Single-crystal X-ray analysis reveals that these complexes contain a crystallographically unique Fe(II) center surrounded by two axial Phpz ligands and four equatorial cyanide [M(CN)₂]⁻ bridges. It is shown that, using of a ligand with two aromatic rings, an advanced system of weak supramolecular interactions (metal–metal, C–H···M, and π···π stacking contacts) is realized. This ensures additional stabilization of the structures and the absence of solvent-accessible voids due to dense packing. Both complexes are characterized by a highly reproducible two-step SCO behavior, as revealed by different techniques (superconducting quantum interference device magnetometry, optical microscopy, etc.). Research shows the exceptional role of the presence of various supramolecular interactions in the structure and the influence of the bulky substituent in the ligand on SCO behavior. Moreover, the perspective of substituted pyrazines for the design of new switchable materials is supported by this work.

A nontrivial balance between Coulomb repulsion and kinematic effects determines the electronic structure of correlated electron materials. The use of electromagnetic fields strong enough to rival these native microscopic interactions allows us to study the electronic response as well as the time scales and energies involved in using quantum effects for possible applications. We use element-specific transient x-ray absorption spectroscopy and high-harmonic generation to measure the response to ultrashort off-resonant optical fields in the prototypical correlated electron insulator NiO. Surprisingly, fields of up to 0.22 V/angstrom lead to no detectable changes in the correlated Ni 3d orbitals contrary to previous predictions. A transient directional charge transfer is uncovered, a behavior that is captured by first-principles theory. Our results highlight the importance of retardation effects in electronic screening and pinpoints a key challenge in functionalizing correlated materials for ultrafast device operation.

We measure the velocity dispersions of clusters of galaxies selected by the red-sequence Matched-filter Probabilistic Percolation (redMaPPer) algorithm in the first three years of data from the Dark Energy Survey (DES), allowing us to probe cluster selection and richness estimation, λ, in light of cluster dynamics. Our sample consists of 126 clusters with sufficient spectroscopy for individual velocity dispersion estimates. We examine the correlations between cluster velocity dispersion, richness, X-ray temperature, and luminosity, as well as central galaxy velocity offsets. The velocity dispersion–richness relation exhibits a bimodal distribution. The majority of clusters follow scaling relations between velocity dispersion, richness, and X-ray properties similar to those found for previous samples; however, there is a significant population of clusters with velocity dispersions that are high for their richness. These clusters account for roughly 22 per cent of the λ < 70 systems in our sample, but more than half (55 per cent) of λ < 70 clusters at z > 0.5. A couple of these systems are hot and X-ray bright as expected for massive clusters with richnesses that appear to have been underestimated, but most appear to have high velocity dispersions for their X-ray properties likely due to line-of-sight structure. These results suggest that projection effects contribute significantly to redMaPPer selection, particularly at higher redshifts and lower richnesses. The redMaPPer determined richnesses for the velocity dispersion outliers are consistent with their X-ray properties, but several are X-ray undetected and deeper data are needed to understand their nature.

In this paper we put forward some historical notes on the development of computational chemistry toward applications of x-ray spectroscopies. We highlight some of the important contributions by Enrico Clementi as method and program developer and as a supporter of this branch of computational research. We bring up a modern example based on the very recent experimental development of x-ray absorption of cationic molecules. As we show this spectroscopy poses new challenges for electronic structure theory and the electron correlation problem.

The aim of this project was to study what mixed cluster fragments were formed in the interaction between radiation and H₂O-CO₂ clusters formed by adiabatic expansion, both experimentally and using simulations. The experiment was done using a mass spectrometer at the MAX IV synchrotron facility and by studying the time-of-flight of the ionic fragments. All peaks in the mass spectrum were identified by converting the time-of-flight to mass/charge, and the spectrum for two different photon energies (307 eV and 550 eV ) and two different stagnation pressures (1.5 bar and 2.2 bar) were compared. The data showed that mixed clusters were formed, including fragments with extra hydrogen atoms. The mass spectra showed a larger change in peak height and width with increasing pressure than with increasing photon energy. Molecular dynamics simulations were used to study the stability of the identified clusters. The simulated clusters contained CO₂, H₂O and H₂O⁺. As a measure of stability, the largest centre of mass distance between the H₂O⁺ molecule and any other molecule in the cluster in every time step of the simulation was determined. The structure of the more stable clusters was also studied visually. The simulations showed that the clusters vary greatly in stability, but generally clusters with many H₂O molecules were more stable. The stable structures had the H₂O⁺ molecule on one end of the cluster, with its hydrogen atoms directed towards the rest of the molecules. Although the clusters with many H₂O molecules were more stable in the simulations, clusters with many CO₂ molecules were more abundant in the experimental data. This was most likely due to a high amount of CO₂ in the gas used to create the clusters. 

Atmospheric aerosols contain a variety of compounds, among them free amino acids and salt ions. The pH of the aerosol droplets depends on their origin and environment. Consequently, compounds like free amino acids found in the droplets will be at different charge states, since these states to a great extent depend on the surrounding pH condition. In droplets of marine origin, amino acids are believed to drive salt ions to the water surface and a pH-dependent amino acid surface propensity will, therefore, indirectly affect many processes in atmospheric chemistry and physics such as for instance cloud condensation. To understand the surface propensity of glycine, valine, and phenylalanine at acidic, neutral, and basic pH, we used molecular dynamics (MD) simulations to investigate them at three different charge states in water. Their respective surface propensities were obtained by the means of a potential of mean force (PMF) in an umbrella sampling approach. Glycine was found to have no preference for the surface, while both valine and phenylalanine showed high propensities. Among the charge states of the surface-enriched ones, the cation, representing the amino acids at low pH, was found to have the highest affinity. Free energy decomposition revealed that the driving forces depend strongly on the nature of the amino acid and its charge state. In phenylalanine, the main factor was found to be a substantial entropy gain, likely related to the side chain, whereas in valine, hydrogen bonding to the functional groups leads to favorable energies and, in turn, affects the surface propensity. A significant gain in water-water enthalpy was seen for both valine and phenylalanine.

Background: Patients with CHD exhibit reduced isometric muscle strength and muscle mass; however, little is known how these parameters relate. Therefore, the aim was to investigate the relation between isometric limb muscle strength and muscle mass for patients in comparison to age- and sex-matched control subjects.

Methods: Seventy-four patients (35.6 +/- 14.3 years, women n = 22) and 74 matched controls were included. Isometric muscle strength in elbow flexion, knee extension, and hand grip was assessed using dynamometers. Lean mass, reflecting skeletal muscle mass, in the arms and legs was assessed with dual-energy x-ray absorptiometry.

Results: Compared to controls, patients had lower muscle strength in elbow flexion, knee extension, and hand grip, and lower muscle mass in the arms (6.6 +/- 1.8 kg versus 5.8 +/- 1.7 kg, p < 0.001) and legs (18.4 +/- 3.5 kg versus 15.9 +/- 3.2 kg, p < 0.001). There was no difference in achieved muscle force per unit muscle mass in patients compared to controls (elbow flexion 0.03 +/- 0.004 versus 0.03 +/- 0.005 N/g, p = 0.5; grip strength 0.008 +/- 0.001 versus 0.008 +/- 0.001 N/g, p = 0.7; knee extension 0.027 +/- 0.06 versus 0.028 +/- 0.06 N/g, p = 0.5). For both groups, muscle mass in the arms correlated strongly with muscle strength in elbow flexion (patients r = 0.86, controls, r = 0.89), hand grip (patients, r = 0.84, controls, r = 0.81), and muscle mass in the leg to knee extension (patients r = 0.64, controls r = 0.68).

Conclusion: The relationship between isometric muscle strength and limb muscle mass in adults with CHD indicates that the skeletal muscles have the same efficiency as in healthy controls.

When a nuclear explosion occurs certain radionuclides are emitted, notably xenon. Due to the fact that xenon is a noble gas, it is hard to contain and can therefore be detected far from the explosion site. There are four isotopes of xenon that are of interest in the detection of a nuclear explosion: ^131mXe, ^133mXe, ¹³³Xe and ¹³⁵Xe. By constantly measuring the amount of these isotopes in the air, changes in the concentration in an indication that a nuclear explosion has occurred. In this thesis a detector was modelled in GEANT4 and focuses on one kind of noble gas detector: SAUNA - the Swedish Automatic Unit for Noble gas Acquisition. SAUNA uses the coincidence technique in order to determine the concentration of xenon there is in the air. By using the coincidence technique, it is possible to reduce the impact of the background radiation and therefore increase the efficiency of the detector. ¹³³Xe has a coincidence when it first undergoes beta decay, with an endpoint energy of 346 keV, and then emits a 80 keV gamma particle. ¹³⁵Xe has also a dual coincidence, a beta decay with an endpoint energy of 910 keV together with a 250 keV gamma-ray. However both these isotopes have a triple coincidence decay that also can be exploited: for ¹³³Xe, a beta particle with endpoint energy of 346 keV, a 30 keV X-ray and a 45 keV conversion electron, while for ¹³⁵Xe there is instead of the gamma particle a 30 keV X-ray and a 214keV conversion electron that can be emitted together with the beta particle. The 30 keV X-ray together with the beta particle for ¹³³Xe can also be used as a dual coincidence, in that case the conversion electron is ignored. For ¹³³Xe, when a beta particle, a 45 keV conversion electron, and a 30 keV X-ray are emitted, the model was able to detect all three particles in 69.2% ± 0.1 of the cases. However, when only the particles with a detected energy within a 5 keV interval of their generated energies are considered to be in coincidence, then for ¹³³Xe triple coincidence occurs in 22.9% ± 0.2 of the cases. For ¹³⁵Xe the model was able to detect the triple coincidence (between a beta, 214 keV CE and 30 keV X-ray) in 63.5% ± 0.1 of the cases. This work shows that adding another particle in a coincidence reduces the chance to detect the coincidence. The positive effect of adding another particle in a coincidence is that the minimum detectable concentration of xenon should be smaller. The goal for future detectors should be to make it possible for the detector to take advantage of the triple coincidences but at the same time be also able to use the dual coincidences.

Sarcopenia is a growing public health concern, involving a loss of muscle mass and function, thus resulting in functional impairment. The role of diet in sarcopenia is unknown.

Paper I identified equations by Mifflin-St Jeor and Harris-Benedict as accurate predictive equations for resting energy expenditure among 22 octogenarian men, from the Uppsala Longitudinal Study of Adult Men (ULSAM), using indirect calorimetry as a reference. Our results address the importance of validating the equation in the study population.

Papers II, III, and IV aimed to increase the understanding of the role of dietary patterns (DP) in sarcopenia and its individual components. Lean muscle mass index (LMI) was determined using dual-energy X-ray absorptiometry (DXA).

In Papers II and III, DPs were defined at baseline using a 7-day food record from ULSAM (mean age 71 years). Sarcopenia was defined 16 years later. In Paper IV, DPs were defined at baseline using a food frequency questionnaire in women from the Swedish Mammography Cohort Clinical (SMCC; mean age 67 years). Sarcopenia was defined 12 years later.

Paper II used the old definition by the European Working Group on Sarcopenia in Older People (EWGSOP1) (prevalence of sarcopenia: 21% of 254). Papers III and IV used the new definition (EWGSOP2) (prevalence of sarcopenia: 19% of 257, and incidence of sarcopenia 4% of 1,212, respectively).

Paper II used two a priori DPs (modified Mediterranean Diet Score and modified Healthy Diet Indicator). Higher adherence to a Mediterranean-like diet was associated with a lower prevalence of sarcopenia at follow-up.

Paper III defined four a posteriori DPs. Higher adherence to DP2 (characterized by high intake of vegetables, fruits, poultry, rice, and pasta) was associated with a lower prevalence of sarcopenia at follow-up.

In Paper IV, the associations between DPs (an a priori defined Mediterranean-like and three a posteriori) and sarcopenia displayed no clear associations. However, a DP characterized by a high intake of vegetables, fruits, nuts, grains, poultry, fatty fish, and fermented milk was associated with a higher appendicular LMI at baseline, better muscle function at follow-up, and displayed non-linear associations with changes in appendicular LMI. A DP characterized by a high intake of boiled potatoes, dairy, grains, pancake, and sweet bakery, and a low intake of wine/spirits and poultry displayed non-linear associations with changes in appendicular LMI.

Thus, dietary patterns with a common feature of being considered a healthy choice may be important for muscle function, muscle mass, and sarcopenia.

Biophysical screening of compound libraries for the identification of ligands that interact with a protein is efficient, but does typically not reveal if (or how) ligands may interfere with its functional properties. For this a biochemical/functional assay is required. But for proteins whose function is dependent on a conformational change, such assays are typically complex or have low throughput. Here we have explored a high-throughput second-harmonic generation (SHG) biosensor to detect fragments that induce conformational changes upon binding to a protein in real time and identify dynamic regions. Multiwell plate format SHG assays were developed for wild-type and six engineered single-cysteine mutants of acetyl choline binding protein (AChBP), a homologue to ligand gated ion channels (LGICs). They were conjugated with second harmonic-active labels via amine or maleimide coupling. To validate the assay, it was confirmed that the conformational changes induced in AChBP by nicotinic acetyl choline receptor (nAChR) agonists and antagonists were qualitatively different. A 1056 fragment library was subsequently screened against all variants and conformational modulators of AChBP were successfully identified, with hit rates from 9–22%, depending on the AChBP variant. A subset of four hits was selected for orthogonal validation and structural analysis. A time-resolved grating-coupled interferometry-based biosensor assay confirmed the interaction to be a reversible 1-step 1 : 1 interaction, and provided estimates of affinities and interaction kinetic rate constants (K_D = 0.28–63 μM, k_a = 0.1–6 μM⁻¹ s⁻¹, k_d = 1 s⁻¹). X-ray crystallography of two of the fragments confirmed their binding at a previously described conformationally dynamic site, corresponding to the regulatory site of LGICs. These results reveal that SHG has the sensitivity to identify fragments that induce conformational changes in a protein. A selection of fragment hits with a response profile different to known LGIC regulators was characterized and confirmed to bind to dynamic regions of the protein.

Hip and knee joint replacements have been some of the most successful surgeries for the treatment of patients with chronic pain due to arthritis. A current challenge is however the younger and more active patients, which demands longer-lasting devices that will withstand several decades of cyclic loading. Corrosion and wear products are herein a concern since they can cause localized inflammation leading to periprosthetic bone loss and potentially implant loosening, necessitating revision surgery. One approach to overcome the long-term issues is to develop materials more resistant to wear and corrosion, as well as materials giving less of an inflammatory response, e.g. by depositing a ceramic coating which acts as a barrier to the release of metal ions from the substrate as well as improving the wear resistance. Silicon nitride is a promising candidate because of its low wear rates and the possibility to limit the adverse effects of wear debris due to its slow dissolution in aqueous solutions.

Purpose of the study

This study aimed to investigate the dissolution and biocompatibility of SiCrNbN coatings deposited on cobalt chromium (CoCr) substrates. We hypothesized that the ceramic coating will reduce metal ion release compared to uncoated CoCr without affecting its biocompatibility.

MethodsThe SiCrNbN coatings were deposited on CoCr disc substrates by reactive sputtering in an in-house built equipment, allowing for combinatorial processes, using Si, Cr and Nb solid targets. Nitrogen was supplied as a reactive gas. To improve the adhesion of the coating a CrN interlayer was deposited. The coatings were characterized in 9 points using x-ray photoelectron spectroscopy (XPS), vertical scanning interferometry (VSI) and scanning electron microscopy (SEM). The points were placed in a 3x3 grid with 22.5 mm between each point. 

The dissolution was evaluated by exposing the coated samples to cell media for 7 days. The obtained extracts were diluted (neat extracts (1:1), and 3 two-fold dilutions (1:2, 1:4 and 1:8)) and used to measure ion levels with inductively coupled plasma (ICP-OES) and to assess indirect biocompatibility in vitro using the tetrazolium dye MTT

 and L929 fibroblast cells. 

Results

The XPS results revealed compositional gradients with Si ranging between 27.4-32.8 at.%, Cr 4.1-10.9 at.%, Nb 3.5-8.4 at.%, N 41.8-46.8 at.% and O 10.9-14.6 at.%. SEM revealed coating thicknesses between 320-590 nm, and interlayers approx. 50 nm thick. Images displayed an overall smooth surface with an average roughness, Ra, of 5.6 to 9.3 nm, similar for all points. Grooves from polishing and occasional features at the microscale were observed, likely formed during deposition. The ICP results showed a reduction in Co ions from the substrate in the coated samples compared to uncoated. The cell viability results suggest that fibroblasts tolerated the neat extracts and their dilutions (1:1, 1:2, 1:4) obtained from the coated samples in a dose-dependent manner. 

ConclusionsThe findings from this study suggest that the differences in composition did not affect the surface properties. The material characteristics indicate that silicon nitride has a promising potential to be used as a coating in metallic implants to improve corrosion resistance and reduce ion release, warranting further biological evaluation.