Furan fatty acid concentrations in tea infusions prepared from green,black, and herbal teas

Furan fatty acids (FuFAs) are valuable antioxidants with highly effective radical scavenging properties which are widely distributed at low levels in food. Previous research indicated that tea is a valuable source of FuFAs. However, tea is only consumed in form of infusions. To fill this gap, we prepared infusions from different herbal, green, and black teas. Initial measurements with GC-MSMS of tea verified previous findings that 11-(3,4-dimethyl-5-penylfuran-2-yl)-undecanoic acid (11D5) was the prevalent FuFA in tea matrix. Therefore, 11D5 was quantified in tea infusions by means of UHPLC-MSMS equipment after mild alkaline hydrolysis. While herbal tea infusions were low or free of FuFAs, 11D5 was detectable in all samples of green and black tea infusions. Amounts of 11D5 were higher in green tea than in black tea. Moreover, Darjeeling tea infusions were by ~30% richer in 11D5 than black and green teas from other regions. Each cup of green and black tea infusion may provide 20–60 μg 11D5, which is about 5% of the amounts found in tea samples. Spread over the day, regular tea consumption may contribute to the intake of valuable FuFAs.     

Cross-sector collaboration within Dutch flood risk governance: historical analysis of external triggers

ABSTRACT

This article synthesizes the literature on Dutch flood risk governance to analyze how external conditions shaped past and present dynamics of cross-sector collaboration for integrated flood risk management in the Netherlands. It traces the extent to which policy and legal frameworks, socio-economic circumstances, political realities, power relations and conflict situations have influenced attempts at collaboration between flood safety, spatial planning, environmental protection and other sectors. Despite the growing interdependences, existing power relations between the sectors are characterized by the dominance of the water sector. Hence, cross-sector collaboration can develop as long as it does not compromise flood safety.     

LIQHYSMES storage unit – Hybrid energy storage concept combining liquefied hydrogen with Superconducting Magnetic Energy Storage

A new energy storage concept for variable renewable energy, LIQHYSMES, has been proposed which combines the use of LIQuid HYdrogen (LH2) with Superconducting Magnetic Energy Storage (SMES). LH2 with its high volumetric energy density and, compared with compressed hydrogen, increased operational safety is a prime energy carrier for large scale stationary energy storage. But balancing load or supply fluctuations from seconds to several hours with hydrogen alone is difficult due to the response times of the flow control, and an additional short-term electrical energy storage will be needed. For this purpose a compact LIQHYSMES Storage Unit is proposed which integrates the H2 liquefaction part, the LH2 tank and the SMES based on Magnesium Diboride and cooled by the LH2 bath. This allows jointly utilizing the cryogenic infrastructure and reducing the otherwise significant H2 liquefaction losses by introducing a novel process with “cold recovery”. Preliminary target numbers for this process, key parameters for a complete LIQHYSMES model plant, simulations on the anticipated buffering behaviour, a loss analysis and a crude cost estimate are given.     

Assessment of biofuels supporting policies using the BioTrans model

The introduction of advanced, 2nd generation biofuels is a difficult to forecast process. Policies may impact the timing of their introduction and the future biofuels mix. The least-cost optimization model BioTrans supports policy analyses on these issues. It includes costs for all parts of the supply chain, and endogenous learning for all biofuels technologies, including cost reductions through scale. BioTrans shows that there are significant lock-in effects favouring traditional biofuels, and that the optimal biofuels mix by 2030 is path dependent. The model captures important barriers for the introduction of emerging technologies, thereby providing valuable quantitative information that can be used in analyses of biofuels supporting policies. It is shown that biodiesel from oil crops will remain a cost effective way of producing biofuels in the medium term at moderate target levels. Aiming solely at least-cost biofuel production is in conflict with a longer term portfolio approach on biofuels, and the desire to come to biofuels with the lowest greenhouse gas emissions. Lowering the targets because of environmental constraints delays the development of 2nd generation biofuels, unless additional policy measures (such as specific sub targets for these fuels) are implemented.     

Liquid Chromatographic Determination of Polycyclic Aromatic Hydrocarbon Isomers of Molecular Weight 278 and 302 in Environmental Standard Reference Materials

Abstract

Polycyclic aromatic hydrocarbons (PAHs) of molecular weight (MW) 278 (dibenzanthracene isomers) and 302 (dibenzopyrene/dibenzofluoranthene isomers) are seldom measured in environmental samples. A multidimensional liquid chromatography (LC) procedure was developed for the quantification of isomers of MW278 and 302. The multidimensional LC procedure consists of normal-phase LC to isolate the PAH isomer groups followed by analysis of the isomeric groups by reversed-phase LC with fluorescence detection. Using the multidimensional LC procedure, six isomers of MW 278 and nine isomers of MW 302 were quantified in four environmental Standard Reference Materials (SRMs): coal tar (SRM 1597), air particulate matter (SRMs 1648 and 1649), and marine sediment (SRM 1941).     

Development and Analysis of Three Diesel Particulate-Related Standard Reference Materials for the Determination of Chemical,Physical, and Biological Characteristics

The National Institute of Standards and Technology (NIST) has recently issued three Standard Reference Materials (SRMs) related to diesel particulate matter: SRM 1650a, Diesel Particulate Matter; SRM 2975, Diesel Particulate Matter (Industrial Forklift); and SRM 1975, Diesel Particulate Extract. These three materials have certified and reference concentrations for selected polycyclic aromatic hydrocarbons (PAHs) including many alkyl-substituted compounds. SRM 1650a is the reissue of an existing material and SRMs 2975 and 1975 represent new materials. The characterization of the PAH content of these three diesel particulate-related SRMs is presented with a discussion of the approach for the certification of PAH concentrations. In addition, the physical and biological characterization of these materials is discussed. A review of customer reported uses of these SRMs in the chemical, physical, and biological sciences is also provided.     

Chromophore‐Linked Substrate (CLS405): Probing Metallo‐β‐Lactamase Activity and Inhibition

Serine‐ and metallo‐β‐lactamases present a threat to the clinical use of nearly all β‐lactam antibiotics, including penicillins, cephalosporins, and carbapenems. Efforts to develop metallo‐β‐lactamase (MBL) inhibitors require suitable screening platforms to allow the rapid determination of β‐lactamase activity and efficient inhibition. Unfortunately, the platforms currently available are not ideal for this purpose. Further progress in MBL inhibitor identification requires inexpensive and widely applicable assays. Herein the identification of an inexpensive and stable chromogenic substrate suitable for use in assays of clinically relevant MBLs is described. (6R,7R)‐3‐((4‐Nitrophenoxy)methyl)‐8‐oxo‐7‐(2‐phenylacetamido)‐5‐thia‐1‐azabicyclo[4.2.0]oct‐2‐ene‐2‐carboxylic acid 5,5‐dioxide (CLS405) was synthesised in a three‐step protocol. CLS405 was then characterised spectroscopically, and its stability and kinetic properties evaluated. With a Δλ_max value of 100 nm between the parent and hydrolysis product, a higher analytical accuracy is possible with CLS405 than with commonly used chromogenic substrates. The use of CLS405 in assays was validated by MBL activity measurements and inhibitor screening that resulted in the identification of N‐hydroxythiazoles as new inhibitor scaffolds for MBLs. Further evaluation of the identified N‐hydroxythiazoles against a panel of clinically relevant MBLs showed that they possess inhibitory activities in the mid‐ to low‐micromolar range. The findings of this study provide both a useful tool compound for further inhibitor identification, and novel scaffolds for the design of improved MBL inhibitors with potential as antibiotics against resistant strains of bacteria.     

A Detailed Model for the Sintering of Polydispersed Nanoparticle Agglomerates

In this study the coagulation, condensation, and sintering of nanoparticles is investigated using a stochastic particle model. Each stochastic particle consists of interacting polydisperse primary particles that are connected to each other. In the model sintering occurs between each individual pair of neighboring primary particles. This is important for particles in which the range of the size of the primary particles varies significantly. The sintering time is obtained from the viscous flow model. The model is solved using a stochastic particle algorithm. The particles are represented in a binary tree that contains the connectivity as well as the degree of sintering information. Particles are forme, coagulate, sinter, and experience condensation according to known rate laws. The particle binary tree, along with it the degree of sintering, is updated after each time step according to the rates of the different processes. The stochastic particle method uses the technique of fictitious jumps and linear process deferment. The theoretical results are fitted against experimental values for the formation of SiO ₂ nanoparticles and computer generated TEM pictures are presented and compared to experiments.