Rism-based pressure-dependent computational spectroscopy

Spectroscopic measurements are an indispensable tool in chemical analysis; even under extreme conditions such as high hydrostatic pressures, they can provide valuable insights. Theoretical methods that can reliably reproduce observables in solution can be used to validate the obtained results. A common theoretical model is the Reference Interaction Site Model (RISM), which was used in this work. In the first part, a previously developed method for calculating IR frequencies with the embedded cluster(EC)-RISM under equilibrium conditions was extended to non-equilibrium thermodynamics for IR spectroscopy. The pressure-dependent IR frequency shifts of TMAO and the cyanide anion were investigated as model systems. Furthermore, EC-RISM was used here for the first time to calculate EPR observables at ambient conditions. First, experiments with the geometrically optimized structure showed that EC-RISM gives significantly better results than a standard continuum calculation despite a large deviation from the experiment. A significant improvement in the direction of the experimental values was achieved by using a large number of snapshots from an ab initio molecular dynamics simulation (AIMD) instead of a single geometry. In general, in the context of the theoretical description of high-pressure effects on proteins, the critical question can be raised whether using force fields parameterized for ambient conditions is appropriate for high-pressure conditions. To answer this question, the pressure dependence of the peptide backbone was investigated in the third part, and the small molecules N-methyl acetamide (NMA) and Ac-Gly/Ala-NHMe were used as model systems. In this work, it was shown that EC-RISM is a suitable method of choice for the calculation of spectroscopic observables in solution. Especially when non-ambient conditions are to be examined, EC-RISM shows its strength since it is relatively easily extensible, e.g., high-pressure environments

User Entrepreneurship in the esports Industry : An exploratory Case Study of the Game Series "Super Smash Bros."

Background: Users are an important but underestimated driver of innovation and entrepreneurship. Therefore, they have a positive impact on the competitive position of companies, the development of industries and the wealth of societies as a whole. Our study focuses on the occurrence and development of user entrepreneurship in the esports industry, which is a modern and fast-growing industry that is also characterized by its over-energetic, over-enthusiastic and over-dynamic users. One compelling case of user entrepreneurship can be observed in the game series “Super Smash Bros.” where users have developed an esports scene out of the game without the active involvement of its publisher Nintendo. Research Purpose: The development of an in-depth understanding of how user entrepreneurship evolves and works in the esports industry. Research Problem: Both, user entrepreneurship and the esports industry, are relatively new research areas that have not yet been sufficiently investigated. As user entrepreneurship is assumed to be more likely in industries that are characterized by uncertainty, ambiguity and evolving demands, and in which the product or service provides enjoyment, we deem the esports industry to provide facilitating conditions for its emergence. Therefore, a deeper understanding of genesis and mechanics has the potential to apply those learnings within the industry and to other industries which may benefit from user entrepreneurship as well. Research Question: How do users and the environment in the esports industry enable the occurrence and flourishing of user entrepreneurship? Method: Ontology – Relativism; Epistemology – Social Constructionism; Methodology – Exploratory Single Embedded Case Study; Data Collection – 12 Semi-structured Interviews supported by Online Forum Narratives; Sampling – Purposeful selection of the first Interviewees followed by Snowball Sampling; Data Analysis – Content Analysis (creation of a tree-diagram based on quotes, sub-categories, generic categories and main categories) Conclusion: We developed a model that represents the most important factors for user entrepreneurship apparent in the esports industry and describes how they enable its occurrence and flourishing. Thereby we contribute to an understanding of the interdependence between user- and environmental-specific enabling factors for user entrepreneurship. Our results suggest that the presence of a supportive environment fosters the user entrepreneur’s motivation, knowledge and skills. Practical Implications: Emerging from our findings, implications for producer firms, individual user entrepreneurs and user entrepreneurship communities were developed on how to purposely foster user entrepreneurship and benefit from its occurrence

Positive and negative cooperativity of TNF and Interferon-γ in regulating synovial fibroblast function and B cell survival in fibroblast/B cell co-cultures

Synovial fibroblasts (SF) were reported to produce B cell activating factor (BAFF) in response to stimulation with interferon-gamma (IFN-gamma) or tumor necrosis factor (TNF). However, the influence of these pro-inflammatory cytokines on other receptors/ligands of the TNF superfamily or associated cytokine receptors in SF has not been investigated yet. Here we show the differential regulation of BAFF (CD257), Fn14 (CD266), TACI (CD267), BAFF-R (CD268), BCMA (CD269), CD40 ligand (CD40L, CD154), IFN-gamma R (CD119), Leptin receptor (ObR, CD295), VCAM-1 (CD106) and membrane TGF-beta in isolated SF and the impact of IFN-gamma/TNF co-incubation on proliferation, IL-6 and IL-8 production. In addition, the impact of differentially stimulated SF on B cell survival in co-cultures was assessed. Surface cytokines and cytokine receptors were detected by flow cytometry. Soluble cytokine receptors and cytokines were quantified by ELISA. Proliferation was assessed by cell titer blue. Murine B cell survival in fibroblast/ B cell co-cultures was determined by annexin V/propidium iodide staining and flow cytometry. IFN-gamma together with TNF synergistically and significantly increased the cell surface levels of BAFF, Fn14, TACI, BAFF-R, BCMA, CD40L, ObR and IFN-gamma R in rheumatoid arthritis SF after 72h incubation. Soluble BAFF was only induced by IFN-gamma and inhibited by TNF. Addition of TWEAK had no influence on proliferation or IL-8 production but decreased TNF-induced IL-6 production, whereas APRIL, BAFF and leptin did not modulate TNF or TNF/IFN-gamma-induced proliferation or cytokine production. Proliferation was increased by TNF and further enhanced by the addition of IFN-gamma. In co-culture experiments, SF stimulated with TNF/IFN but not TNF or IFN-gamma alone increased shedding of VCAM-1 and expression of membrane TGF beta, which was associated with reduced survival of murine B cells. IFN-gamma and TNF regulate the expression of TNF family member cytokines and associated receptors. Ligation of IFN-gamma R and Fn14 under pro-inflammatory conditions modulated IL-6/IL-8 production and proliferation. In B cell/SF co-cultures, the combination of TNF/IFN reduced B cell survival possibly via enhanced VCAM-1 shedding and/or increased TGF-beta production. IFN-gamma is necessary for the observed effects on B cell survival and SF cytokine production and emphasizes its anti-inflammatory role in rheumatoid arthritis

Dissecting the Molecular Origin of <i>g</i> -Tensor Heterogeneity and Strain in Nitroxide Radicals in Water: Electron Paramagnetic Resonance Experiment versus Theory

Nitroxides are common EPR sensors of microenvironmental properties such as polarity, numbers of H-bonds, pH, and so forth. Their solvation in an aqueous environment is facilitated by their high propensity to form H-bonds with the surrounding water molecules. Their g- and A-tensor elements are key parameters to extracting the properties of their microenvironment. In particular, the gxx value of nitroxides is rich in information. It is known to be characterized by discrete values representing nitroxide populations previously assigned to have different H-bonds with the surrounding waters. Additionally, there is a large g-strain, that is, a broadening of g-values associated with it, which is generally correlated with environmental and structural micro-heterogeneities. The g-strain is responsible for the frequency dependence of the apparent line width of the EPR spectra, which becomes evident at high field/frequency. Here, we address the molecular origin of the gxx heterogeneity and of the g-strain of a nitroxide moiety (HMI: 2,2,3,4,5,5-hexamethylimidazolidin-1-oxyl, C9H19N2O) in water. To treat the solvation effect on the g-strain, we combined a multi-frequency experimental approach with ab initio molecular dynamics simulations for structural sampling and quantum chemical EPR property calculations at the highest realistically affordable level, including an explicitly micro-solvated HMI ensemble and the embedded cluster reference interaction site model. We could clearly identify the distinct populations of the H-bonded nitroxides responsible for the gxx heterogeneity experimentally observed, and we dissected the role of the solvation shell, H-bond formation, and structural deformation of the nitroxide in the creation of the g-strain associated with each nitroxide subensemble. Two contributions to the g-strain were identified in this study. The first contribution depends on the number of hydrogen bonds formed between the nitroxide and the solvent because this has a large and well-understood effect on the gxx-shift. This contribution can only be resolved at high resonance frequencies, where it leads to distinct peaks in the gxx region. The second contribution arises from configurational fluctuations of the nitroxide that necessarily lead to g-shift heterogeneity. These contributions cannot be resolved experimentally as distinct resonances but add to the line broadening. They can be quantitatively analyzed by studying the apparent line width as a function of microwave frequency. Interestingly, both theory and experiment confirm that this contribution is independent of the number of H-bonds. Perhaps even more surprisingly, the theoretical analysis suggests that the configurational fluctuation broadening is not induced by the solvent but is inherently present even in the gas phase. Moreover, the calculations predict that this broadening decreases upon solvation of the nitroxide.</p

The Chemical Shift Baseline for High-Pressure NMR Spectra of Proteins

High-pressure (HP) NMR spectroscopy is an important method for detecting rare functional states of proteins by analyzing the pressure response of chemical shifts. However, for the analysis of the shifts it is mandatory to understand the origin of the observed pressure dependence. Here we present experimental HP NMR data on the N-15-enriched peptide bond model, N-methylacetamide (NMA), in water, combined with quantum-chemical computations of the magnetic parameters using a pressure-sensitive solvation model. Theoretical analysis of NMA and the experimentally used internal reference standard 4,4-dimethyl-4-silapentane-1-sulfonic (DSS) reveal that a substantial part of observed shifts can be attributed to purely solvent-induced electronic polarization of the backbone. DSS is only marginally responsive to pressure changes and is therefore a reliable sensor for variations in the local magnetic field caused by pressure-induced changes of the magnetic susceptibility of the solvent

Pressure-dependent electronic structure calculations using integral equation-based solvation models

Recent methodological progress in quantum-chemical calculations using the "embedded cluster reference interaction site model" (EC-RISM) integral equation theory is reviewed in the context of applying it as a solvation model for calculating pressure-dependent thermodynamic and spectroscopic properties of molecules immersed in water. The methodology is based on self-consistent calculations of electronic and solvation structure around dissolved molecules where pressure enters the equations via an appropriately chosen solvent response function and the pure solvent density. Besides specification of a dispersion-repulsion force field for solute-solvent interactions, the EC-RISM approach derives the electrostatic interaction contributions directly from the wave function. We further develop and apply the method to a variety of benchmark cases for which computational or experimental reference data are either available in the literature or are generated specifically for this purpose in this work. Starting with an enhancement to predict hydration free energies at non-ambient pressures, which is the basis for pressure-dependent molecular population estimation, we demonstrate the performance on the calculation of the autoionization constant of water. Spectroscopic problems are addressed by studying the biologically relevant small osmolyte TMAO (trimethylamine N-oxide). Pressure-dependent NMR shifts are predicted and compared to experiments taking into account proper computational referencing methods that extend earlier work. The experimentally observed IR blue-shifts of certain vibrational bands of TMAO as well as of the cyanide anion are reproduced by novel methodology that allows for weighing equilibrium and non-equilibrium solvent relaxation effects. Taken together, the model systems investigated allow for an assessment of the reliability of the EC-RISM approach for studying pressure-dependent biophysical processes

Indicators of Global Climate Change 2022: annual update of large-scale indicators of the state of the climate system and human influence

Abstract. Intergovernmental Panel on Climate Change (IPCC) assessments are the trusted source of scientific evidence for climate negotiations taking place under the United Nations Framework Convention on Climate Change (UNFCCC), including the first global stocktake under the Paris Agreement that will conclude at COP28 in December 2023. Evidence-based decision-making needs to be informed by up-to-date and timely information on key indicators of the state of the climate system and of the human influence on the global climate system. However, successive IPCC reports are published at intervals of 5–10 years, creating potential for an information gap between report cycles. We follow methods as close as possible to those used in the IPCC Sixth Assessment Report (AR6) Working Group One (WGI) report. We compile monitoring datasets to produce estimates for key climate indicators related to forcing of the climate system: emissions of greenhouse gases and short-lived climate forcers, greenhouse gas concentrations, radiative forcing, surface temperature changes, the Earth's energy imbalance, warming attributed to human activities, the remaining carbon budget, and estimates of global temperature extremes. The purpose of this effort, grounded in an open data, open science approach, is to make annually updated reliable global climate indicators available in the public domain (https://doi.org/10.5281/zenodo.8000192, Smith et al., 2023a). As they are traceable to IPCC report methods, they can be trusted by all parties involved in UNFCCC negotiations and help convey wider understanding of the latest knowledge of the climate system and its direction of travel. The indicators show that human-induced warming reached 1.14 [0.9 to 1.4] ∘C averaged over the 2013–2022 decade and 1.26 [1.0 to 1.6] ∘C in 2022. Over the 2013–2022 period, human-induced warming has been increasing at an unprecedented rate of over 0.2 ∘C per decade. This high rate of warming is caused by a combination of greenhouse gas emissions being at an all-time high of 54 ± 5.3 GtCO2e over the last decade, as well as reductions in the strength of aerosol cooling. Despite this, there is evidence that increases in greenhouse gas emissions have slowed, and depending on societal choices, a continued series of these annual updates over the critical 2020s decade could track a change of direction for human influence on climate