Single-conformation spectroscopy of hydrogen bonding networks: Solvation, synthetic foldamers, and neurodegenerative diseases

The hydrogen bond is one of the most important interactions in natural processes ranging from protein folding to chemical reactions. Two complementary methodologies are applied to understanding this important interaction: top-down and bottom-up. Top-down methods use large molecules, such as proteins, revealing secondary structure information. Bottom-up experiments are performed on small molecules, utilizing high-resolution spectroscopy to reveal underlying quantum mechanical effects. The complexity gap is formed between these two experimental regimes; between large and small molecules; between bulk and individual solvent molecules; between classical mechanics calculations and quantum chemical calculations. This dissertation will focus on the application of gas phase, single-conformation ultraviolet (UV) and infrared (IR) spectroscopies to the study of molecules and clusters in the size and solvation complexity gap, with the goal of bridging the gulf between the two experimental approaches. Single-conformation spectroscopy is perfectly suited to study solvation. Solvent molecules, in many instances water, can be frozen onto the solute in a stepwise manner. Here, we solvate a prototypical flexible bichromophore—1,2-diphenoxyethane (DPOE)—by stepwise addition of water molecules. Single-conformation spectroscopy reveals both the structural perturbations associated with water molecule addition and their effect on DPOE’s pair of closely spaced excited electronic states. These experimental studies provide excellent insight into solvent effects on vibronic and excitonic coupling, and can be used to further develop the models used to describe such processes. Similarly, single-conformation spectroscopy can reveal the effects of conformational flexibility on the innate conformational preferences and hydrogen bonding motifs in peptides. Results obtained from a study of a cyclically constrained γ peptide, γACHC, reveal that increased conformational flexibility can be controlled by synthetic chemists in order to direct folding into pre-programmed secondary structures and that these structures are stabilized with intramolecular rather than intermolecular hydrogen bonds. This theme of conformational flexibility is continued in studies of glutamine containing peptides. Glutamine—with its flexible, hydrogen bond forming sidechain—is intimately involved with neurodegenerative diseases such as Huntington’s disease. Single-conformation studies help reveal the delicate interplay between three different types of hydrogen bonds within the molecule: backbone-backbone, sidechain-backbone, and sidechain-sidechain hydrogen bonds. The importance of these competing hydrogen bonds on the conformational preferences will be discussed both locally and within the larger context of disease pathogenesis

How to assess the adaptive capacity of legislation and policies

Abstract: Intuitively it is clear that institutions can both enhance and hamper the adaptive capacity of a society. But what characteristics make an institution more or less helpful for development and implementation of adaptation strategies? Based on the literature, we developed an analytical framework to assess the adaptive capacity of institutions. The Adaptive Capacity Wheel consists of six dimensions: variety, learning, autonomous ability to change, leadership, legitimacy and resources. The six dimensions were operationalised into 22 criteria and were applied to formal institutions in a content analysis. We conclude that sometimes dimensions and criteria seem to contradict each other, which is not surprising, because this reflects existing paradoxes in the governance of society. We would like to discuss the analytical instrument and its possible uses with the audience of the Amsterdam Conference

Toward healthy and sustainable diets for the 21st century: Importance of sociocultural and economic considerations

Four years after the EAT-Lancet landmark report, worldwide movements call for action to reorient food systems to healthy diets that respect planetary boundaries. Since dietary habits are inherently local and personal, any shift toward healthy and sustainable diets going against this identity will have an uphill road. Therefore, research should address the tension between the local and global nature of the biophysical (health, environment) and social dimensions (culture, economy). Advancing the food system transformation to healthy, sustainable diets transcends the personal control of engaging consumers. The challenge for science is to scale-up, to become more interdisciplinary, and to engage with policymakers and food system actors. This will provide the evidential basis to shift from the current narrative of price, convenience, and taste to one of health, sustainability, and equity. The breaches of planetary boundaries and the environmental and health costs of the food system can no longer be considered externalities. However, conflicting interests and traditions frustrate effective changes in the human-made food system. Public and private stakeholders must embrace social inclusiveness and include the role and accountability of all food system actors from the microlevel to the macrolevel. To achieve this food transformation, a new “social contract,” led by governments, is needed to redefine the economic and regulatory power balance between consumers and (inter)national food system actors

Healthy and Sustainable Diets : Finding co-benefits and trade-offs for the Netherlands

This thesis investigated the association between diet-related environmental impact and health. Data were from 40,000 Dutch participants enrolled in the EPIC-NL cohort with available dietary data at baseline (1993-1997) and in 2015. Environmental impact of diet was calculated using greenhouse gas (GHG) emissions and land use and health was measured according to the Dutch dietary guidelines (RGV). Additionally, mortality risk of chronic diseases was examined. Diet-related environmental impact was not associated with mortality risk. In 2015, participants ate relatively more fish and chicken but comparable quantities of red and processed meat. This resulted in a healthier diet, but similar environmental impact. Scenarios in which 35 grams of meat per day was replaced by vegetables, fruit or fish were environmentally friendlier (< 10% less GHG emission) and healthier (< 19% lower mortality risk). Better adherence to the RGV was healthier and more sustainable. Modelled policy scenarios with a 15% or 30% higher meat price or 10% lower price for fruit and vegetables showed several billion Euros net benefits over a 30-year period. Important dietary patterns for environment and health were characterized by the ratio of plant-based to animal-based foods (patterns 1) or the amount of dairy consumed (patterns 2). Compared to the average diet in EPIC-NL, participants with a ‘plant-based’ diet had a favorable score for environmental impact and health, while participants with the ‘dairy-based’ pattern were slightly healthier but had a higher environmental impact. Health aspects have been central in current dietary guidelines. In order to integrate environmental impact, several adjustments are proposed for profit on both aspects

A Food System Approach for Sustainable Food-Based Dietary Guidelines : An Exploratory Scenario Study on Dutch Animal Food Products

This study explores interconnections between food consumption and production of animal (by-)products in different food system scenarios within the scope of Dutch Food-Based Dietary Guidelines (FBDG). For this scenario study, a Microsoft Excel model was created that include seven scenarios with different quantities of eggs, milk, cheese, beef cattle, broilers, and pigs as input. Number of animals, intake of energy, animal protein, saturated fatty acids (SFAs), trans-fatty acids (TFAs), salt, greenhouse gas emissions (GHGEs), and land use (LU) were calculated and compared with current consumption and reference values. Based on the concept of eating the whole animal, every recommended lean, unprocessed portion of beef comes along with a non-recommended portion of beef (two portions for pork, 0.5 portion for broilers). The reference values for SFAs, TFAs, and salt were not exceeded if the intake of meat is limited to 410 g/week. The scenarios with recommended 450 mL semi-skimmed milk and 40 g/day low-fat cheese results in 36 g/day of butter as by-product, exceeding its acceptable intake three times. The near-vegetarian scenario with recommended amounts of eggs, milk, and cheese, includes only a portion of beef/calf per 6 days and a portion of chicken per 9 weeks as by-products. This scenario more than halves the GHGE and LU. Finally, the scenario that included the maximum recommended amounts of animal products is reachable with half the current size of Dutch livestock. This conceptual framework may be useful in the discussion on how future sustainable FBDG can incorporate a more food system-based approach

Can healthy and sustainable dietary patterns that fit within current dutch food habits be identified?

This study investigated major healthy and sustainable dietary patterns in the Dutch population. Two 24-hour dietary recalls were collected in 2078 participants aged 19–79 years in the Dutch National Food Consumption Survey 2012–2016. Dietary patterns were identified using reduced rank regression. Predictor variables were food groups and response variables were Dutch Healthy Diet index 2015 (DHD15-index) score, greenhouse gas emissions (GHGE), and blue water use. Three patterns were discovered, including a “high fruit and vegetable dietary pattern”, a “low meat dietary pattern”, and a “high dairy, low fruit juices dietary pattern”. Diets in the highest quartile of these patterns had higher DHD15-index score than the average population. However, diets of the “high fruit and vegetable dietary pattern” were associated with higher dietary GHGE (14%) and blue water use (69.2%) compared to the average population. Diets of the “low meat dietary pattern” were associated with lower GHGE (19.6%) and higher blue water use (7.7%). Concluding, the “low meat dietary pattern” was the most healthy and sustainable dietary pattern in this population. The addition of blue water use as an environmental impact indicator shows the difficulty of finding existing dietary patterns that have low environmental impact in all determinants.</p

Are more environmentally sustainable diets with less meat and dairy nutritionally adequate?

Our current food consumption patterns, and in particular our meat and dairy intakes, cause high environmental pressure. The present modelling study investigates the impact of diets with less or no meat and dairy foods on nutrient intakes and assesses nutritional adequacy by comparing these diets with dietary reference intakes

Shifting towards optimized healthy and sustainable Dutch diets : impact on protein quality

Purpose: To reduce the environmental impact of Western diets, a reduction of meat consumption and a substitution by plant-based protein sources is needed. This protein transition will affect the quantity and quality of dietary protein. Therefore, the aim of this study was to evaluate the protein adequacy of diets optimized for nutritional health and diet-related greenhouse gas emission (GHGE). Methods: Data from 2150 adult participants of the Dutch National Food Consumption Survey were used, with diet assessed using two non-consecutive 24 h dietary recalls. Utilizable protein of current diets per day was based on meal composition and the Protein Digestibility-Corrected Amino Acid Score and was compared to protein requirements. Optimized diets were derived as linear combinations of current diets that minimized GHGE and maximized the Dutch Healthy Diet 2015 score, with/without constraints to keep dietary change within 33% of current consumption. Protein adequacy was evaluated in both current and optimized diets. Results: In all age and gender strata, the healthiest diets had higher GHGE, the most sustainable diets had the lowest dietary quality, though higher than current diets, and protein adequacy remained sufficient. When limiting dietary change to 33% of current consumption, in the most promising trade-off diet GHGE was reduced by 12–16%. The current diet provided 1.4–2.2 times the required amount of utilizable protein. Conclusion: These results suggest that a realistic aim for the next decade might be to reduce diet-related GHGE to 12–16% of the current levels without compromising protein adequacy and diet quality. To achieve global targets, upstream food system transformations are needed with subsequent dietary changes