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Genetic analysis of orotic acid predicted with Fourier transform infrared milk spectra
Get PDFFourier transform infrared spectral analysis is a cheap and fast method to predict milk composition. A not very well studied milk component is orotic acid. Orotic acid is an intermediate in the biosynthesis pathway of pyrimidine nucleotides and is an indicator for the metabolic cattle disorder deficiency of uridine monophosphate synthase. The function of orotic acid in milk and its effect on calf health, health of humans consuming milk or milk products, manufacturing properties of milk, and its potential as an indicator trait are largely unknown. The aims of this study were to determine if milk orotic acid can be predicted from infrared milk spectra and to perform a large-scale phenotypic and genetic analysis of infrared-predicted milk orotic acid. An infrared prediction model for orotic acid was built using a training population of 292 Danish Holstein and 299 Danish Jersey cows, and a validation population of 381 Danish Holstein cows. Milk orotic acid concentration was determined with nuclear magnetic resonance spectroscopy. For genetic analysis of infrared orotic acid, 3 study populations were used: 3,210 Danish Holstein cows, 3,360 Danish Jersey cows, and 1,349 Dutch Holstein Friesian cows. Using partial least square regression, a prediction model for orotic acid was built with 18 latent variables. The error of the prediction for the infrared model varied from 1.0 to 3.2 mg/L, and the accuracy varied from 0.68 to 0.86. Heritability of infrared orotic acid predicted with the standardized prediction model was 0.18 for Danish Holstein, 0.09 for Danish Jersey, and 0.37 for Dutch Holstein Friesian. We conclude that milk orotic acid can be predicted with moderate to good accuracy based on infrared milk spectra and that infrared-predicted orotic acid is heritable. The availability of a cheap and fast method to predict milk orotic acid opens up possibilities to study the largely unknown functions of milk orotic acid.</p
Defining and Classifying Infrastructural Contestation: Towards a Synergy Between Anthropology and Data Science
No full textThe last decade infrastructure systems have been under strain around the globe. The 2008 financial crisis, the so-called fourth industrial revolution, ongoing urbanisation and climate change have contributed to the emergence of an infrastructural crisis that has been labelled as infrastructural gap. During this period, infrastructure systems have increasingly become sites of public contestation with significant effects on their operation and governance. At stake has been the issues of access to infrastructure, their social and environmental consequences and the ‘modern ideal’ embodied in the design of those socio-technical systems. With this paper we apply a cross-disciplinary methodology in order to document and define the practices of this new wave of infrastructural contestation, taking Greece in the 2008–2017 period as the case study. The synthesis of quantitative and qualitative datasets with ethnographic knowledge help us, furthermore, to record tendencies and patterns in the ongoing phenomenon of infrastructural contestation (This study is part of infra-demos project (www.infrademos.net), which is funded by a VIDI grant awarded by the Dutch Organisation of Science, PI: Prof. Dimitris Dalakoglou, Dept. of Social and Cultural Anthropology, Vrije Universiteit Amsterdam)
Transdisciplinary innovation in irrigated smallholder agriculture in africa
Get PDFBoosting the productivity of smallholder farming systems continues to be a major need in Africa. Challenges relating to how to improve irrigation are multi-factor and multisectoral, and they involve a broad range of actors who must interact to reach decisions collectively. We provide a systematic reflection on findings from the research project EAU4Food, which adopted a transdisciplinary approach to irrigation for food security research in five case studies in Ethiopia, Mali, Mozambique, South Africa and Tunisia. The EAU4Food experiences emphasize that actual innovation at irrigated smallholder farm level remains limited without sufficient improvement of the enabling environment and taking note of the wider political economy environment. Most project partners felt at the end of the project that the transdisciplinary approach has indeed enriched the research process by providing different and multiple insights from actors outside the academic field. Local capacity to facilitate transdisciplinary research and engagement with practitioners was developed and could support the continuation and scaling up of the approach. Future projects may benefit from a longer time frame to allow for deeper exchange of lessons learned among different stakeholders and a dedicated effort to analyse possible improvements of the enabling environment from the beginning of the research process.</p
Impact of in vitro digestion on gastrointestinal fate and uptake of silver nanoparticles with different surface modifications
Get PDFNanomaterials, especially silver nanoparticles (AgNPs), are used in a broad range of products owing to their antimicrobial potential. Oral ingestion is considered as a main exposure route to AgNPs. This study aimed to investigate the impact of the biochemical conditions within the human digestive tract on the intestinal fate of AgNPs across an intestinal in vitro model of differentiated Caco-2/HT29-MTX cells. The co-culture model was exposed to different concentrations (250–2500 µg/L) of pristine and in vitro digested (IVD) AgNPs and silver nitrate for 24 h. ICP-MS and spICP-MS measurements were performed for quantification of total Ag and AgNPs. The AgNPs size distribution, dissolution, and particle concentration (mass- and number-based) were characterized in the cell fraction and in the apical and basolateral compartments of the monolayer cultures. A significant fraction of the AgNPs dissolved (86–92% and 48–70%) during the digestion. Cellular exposure to increasing concentrations of pristine or IVD AgNPs resulted in a concentration dependent increase of total Ag and AgNPs content in the cellular fractions. The cellular concentrations were significantly lower following exposure to IVD AgNPs compared to the pristine AgNPs. Transport of silver as either total Ag or AgNPs was limited (<0.1%) following exposure to pristine and IVD AgNPs. We conclude that the surface chemistry of AgNPs and their digestion influence their dissolution properties, uptake/association with the Caco-2/HT29-MTX monolayer. This highlights the need to take in vitro digestion into account when studying nanoparticle toxicokinetics and toxicodynamics in cellular in vitro model systems.</p
Using Emotions to Frame Issues and Identities in Conflict: Farmer Movements on Social Media
No full textPolarization and group formation processes on social media networks have received ample academic attention, but few studies have looked into the discursive interactions on social media through which intergroup conflicts develop. In this comparative case study, we analyzed two social media conflicts between farmers and animal right advocates to understand how conflicts establish, escalate, and return dormant through issue and identity framing and the discursive use of emotions. The results show that the two groups used the same set of frames throughout the three phases. We identify this as a symmetric conflict framing repertoire. The groups both use a dominant moral frame (animal welfare is of absolute value), but express distinct views on policy solutions. This triggers a contestation of credibility (who knows best and who cares most for animals) in which the two groups use the same set of issue and identity frames to directly oppose each other. The binary opposition is initially established through issue framing but escalates into an identity conflict that involves group labeling and blaming. The discursive use of emotion reinforces this escalation in two ways. First, it reinforces a vicious cycle in the contestation of credibility: While emotions are implicitly used to frame oneself as caring and trustworthy, emotion is explicitly used to frame the other party as deceptive and irrational. Second, disputants use collective emotions as a response to the other group’s offensive actions (blaming) and as a justification of one’s own collective actions. We discuss how this conflict differs from previously studied conflicts to provide plausible explanations for these findings.</p
Combined physical and oxidative stability of food Pickering emulsions
Get PDFMany food products contain lipid droplets dispersed in an aqueous phase (e.g., milk, mayonnaise), thus are oil-in-water (O/W) emulsions. Food emulsions may be subjected to destabilization, both from a physical and a chemical perspective. Physical destabilization is generally prevented by the use of conventional emulsifiers such as surfactants and proteins. Chemical destabilization, in particular lipid oxidation, is a major concern in food products, especially when healthy polyunsaturated fatty acids are present, and this degradation is usually mitigated by the use of synthetic antioxidants, often in large amounts. The use of alternative ingredients for the formulation of food emulsions has been emerging, for example solid particles (so-called Pickering particles, that are very popular nowadays) that irreversibly adsorb to the interface and therewith provide high physical stability; or natural antioxidants such as tocopherols and rosemary extracts, which are attractive in the current clean-label trend to prevent lipid oxidation. The efficiency of these natural antioxidants is unfortunately often not optimal, which can be explained by their tendency to locate into the oil or water phase, whereas lipid oxidation is initiated at the oil-water interface, and thus is the place where antioxidants should be located to optimally exert their protective effect. The objective of this project was to develop food emulsions with a new and controlled architecture directed at yielding both excellent physical and oxidative stability. In these emulsions the oil droplets were covered by food-grade Pickering particles that exert a double role: they act as physical stabilizers, and as a reservoir for antioxidant molecules located close to the oil-water interface, therewith preventing the first lipid oxidation events, which is expected to drastically enhance antioxidant activity. The first part of this thesis focused on the preparation and characterization of a new food-grade lipid-based Pickering particles, referred to as colloidal lipid particles (CLPs). We prepared both surfactant-covered and protein-covered CLPs, and found that the type of emulsifier largely determined their morphology: protein-covered CLPs were roughly spherical, whereas surfactant-covered CLPs looked more lath-like (Chapters 3 and 6). We also showed that the lipid material alters the crystal polymorphism and subsequent CLP structure, which consequently influenced their performance as emulsion stabilizers (Chapter 3). For instance, surfactant-covered CLPs containing only high melting point lipids showed highly ordered crystalline structures, and formed jammed, cohesive interfacial layers once adsorbed onto oil droplets, whereas the ones containing a fraction of low melting point lipids showed less ordered crystalline structures and formed thin and bridged layers. Since protein-covered CLPs were particularly resilient to subsequent emulsification processes, these particles were used to study the formation of emulsion droplets in a microfluidic device and their stability to short-term coalescence (Chapter 4). We found a non-monotonic dependency of the droplet stability on the particle concentration: at low surface coverage, CLPs had a destabilizing effect as incompletely covered surfaces led to droplet-droplet bridging and subsequent coalescence, whereas at higher surface coverage, particles formed an effective barrier against droplet coalescence, resulting in physically stable emulsions over the time scales probed. As a next step, we investigated lipid oxidation in Pickering emulsions stabilized by protein-based CLPs that did not contain antioxidants (Chapter 5). We showed that these Pickering emulsions had a similar oxidative stability as conventional protein-stabilized emulsions for a similar composition of the oil droplets. Yet, when in both emulsions the same amount of solid lipids was present (either as stabilizing CLPs, or within the oil droplet core), a Pickering emulsion had a higher physicochemical stability. This shows that the location of crystallizable lipids influences lipid oxidation in O/W emulsions, and thus needs to be carefully considered in emulsion design. CLPs that did contain the lipophilic antioxidant α-tocopherol are presented in Chapter 6. The chemical stability of α-tocopherol was negatively influenced by lipid crystallization that probably promoted the localization of α-tocopherol close to the particle surface, which was further enhanced by emulsifiers that actively induce lipid crystallization. When applied as Pickering stabilizers in O/W emulsions (Chapter 7), lipid oxidation was reduced compared to control emulsions with the same composition and structure, but where the antioxidant was present in the core of the oil droplets. This confirmed that the interfacial localization of the antioxidant is crucial to prevent lipid oxidation in emulsions, and that the two main instability issues (i.e., physical and chemical instability) of emulsions can be mitigated through one single approach. After establishing the proof of concept with the CLPs, we used biobased particles (that may contain antioxidants) from various natural sources to stabilize O/W emulsions (Chapter 8). Emulsions stabilized by matcha tea powder or spinach leaf powder were both highly physically and oxidatively stable, which shows that the double functionality that we achieved using purposely built particles (CLPs) can also be achieved with naturally occurring particles. In the general discussion of the thesis (Chapter 9) we describe that the dual functionality of CLPs can also be reached using other food components, which makes this approach a generic one. We expect that the system could be further improved, for example, by increasing the residence time of antioxidants at the interface. To do so, we probably need to link the time scale at which the relevant oxidation events occur with those during which the antioxidant actually resides at the interface. Follow-up research on entrapment of antioxidants within particles is needed to reach long residence times at the interface while not compromising the ability of antioxidants to exert their chemical activity. To conclude: through our approach the highly-stable food emulsions of the future may come within reach
The two-stage game approach to coalition formation: Where we stand and ways to go
Get PDFCoalition formation is often analysed in an almost non-cooperative way, as a two-stage game that consists of a first stage comprising membership actions and a second stage with physical actions, such as the provision of a public good. We formalised this widely used approach for the case where actions are simultaneous in each stage. Herein, we give special attention to the case of a symmetric physical game. Various theoretical results, in particular, for cartel games, are provided. As they are crucial, recent results on the uniqueness of coalitional equilibria of Cournot-like physical games are reconsidered. Various concrete examples are included. Finally, we discuss research strategies to obtain results about equilibrium coalition structures with abstract physical games in terms of qualitative properties of their primitives.</p
Logging intensity drives variability in carbon stocks in lowland forests in Vietnam
Get PDFForest degradation in the tropics is generating large carbon (C) emissions. In tropical Asia, logging is the main driver of forest degradation. For effective implementation of REDD+ projects in logged forests in Southeast Asia, the impacts of logging on forest C stocks need to be assessed. Here, we assess C stocks in logged lowland forests in central Vietnam and explore correlations between logging intensity, soil, topography and living aboveground carbon (AGC) stocks. We present an approach to estimate historical logging intensities for the prevalent situation when complete records on logging history are unavailable. Landsat analysis and participatory mapping were used to quantify the density of historical disturbances, used as a proxy of logging intensities in the area. Carbon in AGC, dead wood, belowground carbon (BGC) and soil (SOC) was measured in twenty-four 0.25 ha plots that vary in logging intensity, and data on recent logging, soil properties, elevation and slope were also collected. Heavily logged forests stored only half the amount of AGC of stems ≥10 cm dbh as lightly logged forests, mainly due to a reduction in the number of large (≥60 cm dbh) trees. Carbon in AGC of small trees (5–10 cm dbh), dead wood and BGC comprised only small fractions of total C stocks, while SOC in the topsoil of 0–30 cm depth stored ~50% of total C stocks. Combining logging intensities with soil and topographic data showed that logging intensity was the main factor explaining the variability in AGC. Our research shows large reductions in AGC in medium and heavily logged forests. It highlights the critical importance of conserving big trees to maintain high forest C stocks and accounting for SOC in total C stock estimates.</p
Efficient oxidation and adsorption of As(III) and As(V) in water using a Fenton-like reagent, (ferrihydrite)-loaded biochar
No full textThe by-product of the traditional Fenton reaction, colloidal arsenic-‑iron oxide, is migratable and may cause secondary environmental pollution. This paper reported a new strategy involving oxidizing and immobilizing inorganic arsenic using the Fenton reaction, and avoiding the risk of secondary contamination. Lab synthesized ferrihydrite-loaded biochar (FhBC) was developed for oxidizing and binding As(III) and As(V) in aqueous solution. Batch experiments and a series of spectrum analysis (e.g., X-ray photoelectron spectroscopy [XPS], electron paramagnetic resonance [EPR], and Fourier transform infrared spectroscopy [FTIR]) were conducted to study the oxidizing or adsorption capacity and mechanism. The maximum adsorption capacity of FhBC for As(III) and As(V) is 1.315 and 1.325 mmol/g, respectively. In addition, FhBC has an efficient oxidizing capacity within a wide pH range, which is because biochar promotes the Fenton reaction by acting as an electron donator, electron shuttler, or by providing persistent free radicals. Moreover, the adsorption mechanism was studied by FTIR spectroscopy, XPS, and X-ray diffraction (XRD). The formation of internal spherical complexes and iron oxides with a higher degree of crystallization was observed, which indicate that the products of adsorption are stable and robust in a complex environment and can exist in a highly crystallized form after adsorbing arsenic ions. Therefore, the use of FhBC as an adsorbent for arsenic represents a new strategy of using the Fenton reaction while reducing secondary contamination. These results may contribute to further mechanistic studies or extensive practical applications of FhBC.</p
