Search

The literature on socio-technical transitions considers how technological innovations can be established within the context of an incumbent regime that is often resistant or inflexible to change. Strategic niche management is an approach to catalysing a transition to a new regime using protected ‘niche’ spaces to enable development and experimentation with an innovation. Intermediary actors play an important role in establishing these niches as they facilitate knowledge sharing and build the wider networks and systems needed to support an innovation. The influence of intermediaries within socio-technical transitions and strategic niche management is still an under-researched area. In this paper, we use a decision theatre research process to collect empirical evidence from a range of local stakeholders involved in establishing new district heating projects in the United Kingdom (UK). This method, carried out in a group workshop format, enables understanding of the interactions between stakeholders throughout the stages of the district heating development process. The study suggests that intermediaries can play a role in supporting niche empowering processes. The existing institutional framework surrounding intermediary actors, and the geographical scale at which they work within that framework, are shown to be influential on actors’ agency to choose their approach to empowering an innovation. The work highlights the potential for intermediaries to support the restructuring of this institutional framework to enable more radical ‘stretch and transform’ empowering activities. [ABSTRACT FROM AUTHOR]

Abstract: The dispersal, quiescent crystallization kinetics and morphology of a series of unique polyethylene–polyhedral oligomeric silsesquioxanes (PE-POSS) nanocomposite blends is presented. POSS molecules with long linear alkyl-chain substituents were blended at one composition into a commercial low density polyethylene. Time-resolved Small- and Wide-Angle X-ray scattering (SAXS/WAXS) and thermal techniques were used to elucidate the affect that POSS and its substituent groups have on the dispersal and crystallization kinetics of the host polymer. The miscibility and dispersal of the POSS molecules was seen to increase with the increasing alkyl-chain length substituents suggesting increased compatibility and interaction with the host polymer chains. The POSS molecules act as nucleating agents increasing the crystallinity, crystallization kinetics and influencing the final lamellar morphology. Thus, these unique POSS compounds show great potential as nancomposite filler particles in polyolefins where the alkyl-chain substituent plays a vital role in its compatibility and subsequent improvement of physical properties in the host polymer. [Copyright &y& Elsevier]

Physical Supply Use Tables overcome some of the main limitations of the commonly used Energy Extended Input Output Analysis by describing the Energy Conversion Chain in energy terms only. In this paper, we build on recent advances in the field to construct a Multi-Regional Physical Supply Use Table framework. We use data from the International Energy Agency and have developed open source R packages, thereby enabling easy adoption of the present work. The new framework enables analysts to take into consideration the trade in energy products and to track energy flows across regions. In addition, we expand the existing Physical Supply Use Table framework to provide the mathematical structure with symmetry, by adding a resource extraction matrix at the upstream end of the Energy Conversion Chain, thereby enabling reverse Input–Output calculations. Then, we demonstrate two important applications of the new multi-regional framework. First, we show how the framework can be used for energy security analysis, how the primary energy supply can be broken down by region of origin, and how the exposure to overseas suppliers can be quantified by energy product, and final demand sector. Second, we show how energy-related greenhouse gas emissions can be accounted for and disaggregated in terms of energy use by the energy industry, downstream energy use by final demand sectors, and methane leakages and flaring. The framework, which consistently binds energy products supplied to the economy to the Energy Conversion Chain, may be helpful for numerous subfields of energy analysis and modelling. • Energy analysis is important for understanding global energy and climate issues. • Physical Energy IO analysis overcomes expenditure-based traditional IO limitations. • We construct a Multi-Regional Physical Supply Use Table (MR-PSUT) framework. • The MR-PSUT framework binds energy from extraction to end use, and across borders. • The benefits of the MR-PSUT framework are demonstrated via illustrative examples. [ABSTRACT FROM AUTHOR]

Abstract: The first example of biomimetic siloxane bond formation catalyzed by molecularly imprinted polymers (MIPs) is reported. MIPs were prepared by free-radical polymerization and characterized via a combination of solid-state NMR, infrared spectroscopy, and electron microscopy studies. Methacrylic acid–based polymers with high functional monomer content were observed to catalyze the hydrolysis and condensation of a model monoalkoxysilane to a greater extent when compared with the corresponding blank (non-imprinted) materials and buffer control solutions, as judged by quantitative gas chromatography investigations. Moreover, the polymers were used as biomimetic catalysts to synthesize silica-MIP hybrids with a certain degree of control of the microstructure of the resulting composites. [Copyright &y& Elsevier]

Abstract: Biotransformations make use of biological systems to catalyze or promote specific chemical reactions. Transformations that utilize enzymes as “greener” and milder catalysts compared to traditional reaction conditions are of particular interest. Recently, organosilicon compounds have begun to be explored as non-natural enzymatic substrates for biotransformations. The aims of this study were to screen readily available (approximately eighty) enzymes for their ability to catalyze in vitro siloxane bond formation under mild reaction conditions using a model monoalkoxysilane as the substrate and to make a preliminary evaluation of potential factors that might lead to activity or inactivity of a particular enzyme. Several new hydrolase enzymes were observed to catalyze the formation of the condensation product when compared to peptide controls, or buffer solutions at the same pH, as judged from quantitative analyses by gas chromatography. Aspergillus ficuum phytase, Aspergillus niger phytase, chicken egg white lysozyme, porcine gastric mucosa pepsin, and Rhizopus oryzae lipase all catalyzed the condensation of silanols in aqueous media. Factors involved in determining the activity of an enzyme towards silanol condensation appear to include: the presence of imidazole and hydroxyl functions in the active site; solvent; the presence of water; the surface properties of the enzyme; possible covalent inhibition; and steric factors in the substrate. [ABSTRACT FROM AUTHOR]

• Hypercoordinated complexes with octahedral structure. • Halogen exchange reactions between hexacoordinate tin dihalides produce mixed dihalides. • NMR 119Sn spectroscopy, electrical conductivity and quantum-chemical calculations for investigation of exchange reactions for hexacoordinated complexes. Halogen exchange reactions between hexacoordinate tin dihalides (LnCH 2) 2 SnX 2 and (LnCH 2) 2 SnY 2 (LnCH 2 = C,O-chelate n-membered lactamomethyl ligand, n = 5–7, X, Y = Cl, Br, I) produce mixed dihalides (LnCH 2) 2 SnXY. Along with the signals of original complexes, NMR 119Sn spectra of solutions containing two different homodihalides show the third signal with a median chemical shift. The results of NMR monitoring studies, conductivity data and quantum-chemical calculations suggest that mixed dihalides readily form in solutions, although these complexes have not been isolated as individual compounds. [Display omitted] [ABSTRACT FROM AUTHOR]

Successful ring-expanding insertion reactions of T6 silsesquioxane cages using dialkyl and diarylethoxysilanes have been performed to give the first reported mixed T6D1 and T6D2 silsesquioxane cages. The reactions of hexacyclohexylsilsesquioxane (T6) with dialkyl and diaryldiethoxysilanes give predominantly T6D2 bis-insertion compounds while the reaction of T6 with dimethylethoxysilane gives one T6D1 mono-insertion product and various T6D2 bis-insertion products as isolable components. Three of the ring-expanded products are chiral and it has been shown from their X-ray crystal structures that the pairs of enantiomers, formed as racemic mixtures, co-crystallise together. As well as comparing these structures with related ones in the literature, the possible mechanism of their formation is discussed. [Copyright &y& Elsevier]

Solution 1JSi&z.sbnd;F and 2JC&z.sbnd;F NMR coupling constant and 19F-NMR chemical shift data have been analysed in a series of pentacoordinate silyl monofluoride complexes used to model nucleophilic substitution at silicon. Patterns in the data reveal strong correlations between both coupling constants and 19F-NMR chemical shifts and the degree of substitution displayed by each. Excellent correlation is obtained between the new data and our previous 13C- and 29Si-NMR studies to further confirm the validity of the NMR technique for structural correlation in solution. By pooling the X-ray crystal structures of a large number of compounds of this class from both our own results and the literature we are able to provide a possible explanation for some of the trends in the NMR data we observe in solution. [Copyright &y& Elsevier]

Cuttings from road-verge grass could provide biomass for energy generation, but currently this potential is not exploited. This research assessed the technical, practical and financial feasibility of using grass harvested from road verges as a feedstock in farm-fed anaerobic digestion (AD) plants. The methane potential (191 mL CH 4 g DM −1) and digestion characteristics of verge grass were similar to those of current farm feedstocks; indicating suitability for AD. Ensiling had no significant impact on the biomethane generated. Testing co-digestions of verge grass with current farm feedstocks showed enhanced methane yields, suggesting that verge grass could be a valuable addition to AD feedstock mixes. In a case study of the UK county of Lincolnshire, potential volumes and locations of verge grass biomass were estimated, with capacities and locations of existing AD plants, to assess the potential to supply practical grass volumes. Grass harvesting costs were modelled and compared with other feedstock costs. Finally, the attitudes of AD operators to using verge grass were investigated to understand whether a market for verge grass exists. In a small survey all operators were willing to use it as a feedstock and most were prepared to pay over the estimated harvesting cost. If verge grass was legally recognised as a waste product it could be attractive to AD operators especially where financial incentives to use waste feedstocks are in place. In rural areas, verge grass could be harvested and co-digested by existing farm-fed AD plants, potentially reducing the cost of road verge maintenance and increasing biodiversity. • Verge grass had a methane potential of 222 mL CH 4 g VS −1 or 191 mL CH 4 g DM −1. • This is a similar methane potential to maize. • Adding verge grass to existing AD feedstock mixes can enhance methane production. • Estimated harvesting costs of under £18 t−1 were competitive with other feedstocks. • Four out of five AD plant operators interviewed would pay for verge grass. [ABSTRACT FROM AUTHOR]

• Methodology for assessment of generation-integrated and non-generation-integrated energy storage systems is developed. • Assessment covers economics, environment, and network constraints. • An efficient method of scheduling behind-the-meter storage is designed. • Storage alongside a community hydro scheme in North Wales is investigated. • Storage on a scale of 1 kWh per household can increase scheme membership by >30%. In this paper, we investigate how energy storage can be used to increase the value of community energy schemes through cost reductions, infrastructure support, increased scheme membership, and reduced carbon emissions. A linear programming optimisation framework is developed to schedule the operation of behind-the-meter energy storage such that costs are minimised, while keeping peak demands within allowable limits. This is also extended to model generation-integrated energy storage systems, where the storage is located in the flow of energy from primary source (e.g. wind) to a usable form (e.g. electricity). To demonstrate the potential of energy storage within a real community energy scheme, we present a case study of a community hydro scheme in North Wales, considering both battery storage and a reservoir-based storage system. It is found that either system can be used to substantially increase the membership of the scheme while avoiding impacts on the electricity network, but that storage remains prohibitively expensive when used for self-consumption of renewables and arbitrage. We also investigate the impacts of energy storage on the community's carbon emissions, showing that storage operation appears to provide very little additional reduction in emissions when grid average emissions factors are used. [ABSTRACT FROM AUTHOR]

Macromolecule branching upon polyhedral oligomeric silsesquioxanes (POSS) via "click" chemistry has previously been reported for promoting natural biological responses in vitro , particularly when regarding their demonstrated biocompatibility and structural robustness as potential macromolecule anchoring points. However, "clicking" of large molecules around POSS structures uncovers two main challenges: (1) a synthetic challenge encompassing multi-covalent attachment of macromolecules to a single nanoscale-central position, and (2) purification and separation of fully adorned nanocages from those that are incomplete due to their similar physical characteristics. Here we present peptide decoration to a T 8 POSS nanocage through the attachment of azido-modified trimers. Triglycine- and trialanine-methyl esters "clicked" to 97% and 92% completion, respectively, resulting in 84% and 68% yields of the fully-adorned octamers. The "clicks" halt within 27-h of the reaction time, and efforts to further increase the octamer yield were of negligible benefit. Exploration of reaction conditions reveals multiple factors preventing full octa-arm modification to all available POSS nanocages, and offers insights into macromolecule attachment between both peptides and small inorganic-organic structures, all of which require consideration for future work of this nature.

Malaria is a vector-borne disease that exacts a grave toll in the Global South. The epidemiology of Plasmodium vivax, the most geographically expansive agent of human malaria, is characterised by the accrual of a reservoir of dormant parasites known as hypnozoites. Relapses, arising from hypnozoite activation events, comprise the majority of the blood-stage infection burden, with implications for the acquisition of immunity and the distribution of superinfection. Here, we construct a novel model for the transmission of P. vivax that concurrently accounts for the accrual of the hypnozoite reservoir, (blood-stage) superinfection and the acquisition of immunity. We begin by using an infinite-server queueing network model to characterise the within-host dynamics as a function of mosquito-to-human transmission intensity, extending our previous model to capture a discretised immunity level. To model transmission-blocking and antidisease immunity, we allow for geometric decay in the respective probabilities of successful human-to-mosquito transmission and symptomatic blood-stage infection as a function of this immunity level. Under a hybrid approximation-whereby probabilistic within-host distributions are cast as expected population-level proportions-we couple host and vector dynamics to recover a deterministic compartmental model in line with Ross-Macdonald theory. We then perform a steady-state analysis for this compartmental model, informed by the (analytic) distributions derived at the within-host level. To characterise transient dynamics, we derive a reduced system of integrodifferential equations, likewise informed by our within-host queueing network, allowing us to recover population-level distributions for various quantities of epidemiological interest. In capturing the interplay between hypnozoite accrual, superinfection and acquired immunity-and providing, to the best of our knowledge, the most complete population-level distributions for a range of epidemiological values-our model provides insights into important, but poorly understood, epidemiological features of P. vivax., (© 2024. The Author(s).)

Reported herein is the development of assays for the spectrophotometric quantification of biocatalytic silicon-oxygen bond hydrolysis. Central to these assays are a series of chromogenic substrates that release highly absorbing phenoxy anions upon cleavage of the sessile bond. These substrates were tested with silicatein, an enzyme from a marine sponge that is known to catalyse the hydrolysis and condensation of silyl ethers. It was found that, of the substrates tested, tert -butyldimethyl(2-methyl-4-nitrophenoxy)silane provided the best assay performance, as evidenced by the highest ratio of enzyme catalysed reaction rate compared with the background (uncatalysed) reaction. These substrates were also found to be suitable for detailed enzyme kinetics measurements, as demonstrated by their use to determine the Michaelis-Menten kinetic parameters for silicatein.

A characteristic of malaria in all its forms is the potential for superinfection (that is, multiple concurrent blood-stage infections). An additional characteristic of Plasmodium vivax malaria is a reservoir of latent parasites (hypnozoites) within the host liver, which activate to cause (blood-stage) relapses. Here, we present a model of hypnozoite accrual and superinfection for P. vivax. To couple host and vector dynamics for a homogeneously-mixing population, we construct a density-dependent Markov population process with countably many types, for which disease extinction is shown to occur almost surely. We also establish a functional law of large numbers, taking the form of an infinite-dimensional system of ordinary differential equations that can also be recovered by coupling expected host and vector dynamics (i.e. a hybrid approximation) or through a standard compartment modelling approach. Recognising that the subset of these equations that model the infection status of the human hosts has precisely the same form as the Kolmogorov forward equations for a Markovian network of infinite server queues with an inhomogeneous batch arrival process, we use physical insight into the evolution of the latter process to write down a time-dependent multivariate generating function for the solution. We use this characterisation to collapse the infinite-compartment model into a single integrodifferential equation (IDE) governing the intensity of mosquito-to-human transmission. Through a steady state analysis, we recover a threshold phenomenon for this IDE in terms of a parameter [Formula: see text] expressible in terms of the primitives of the model, with the disease-free equilibrium shown to be uniformly asymptotically stable if [Formula: see text] and an endemic equilibrium solution emerging if [Formula: see text]. Our work provides a theoretical basis to explore the epidemiology of P. vivax, and introduces a strategy for constructing tractable population-level models of malarial superinfection that can be generalised to allow for greater biological realism in a number of directions., (© 2023. The Author(s).)

The influenza pandemic of 1918-19 was the most devastating pandemic of the 20th century. It killed an estimated 50-100 million people worldwide. In late 1918, when the severity of the disease was apparent, the Australian Quarantine Service was established. Vessels returning from overseas and inter-state were intercepted, and people were examined for signs of illness and quarantined. Some of these vessels carried the infection throughout their voyage and cases were prevalent by the time the ship arrived at a Quarantine Station. We study four outbreaks that took place on board the Medic, Boonah, Devon, and Manuka in late 1918. These ships had returned from overseas and some of them were carrying troops that served in the First World War. By analysing these outbreaks under a stochastic Bayesian hierarchical modeling framework, we estimate the transmission rates among crew and passengers aboard these ships. Furthermore, we ask whether the removal of infectious, convalescent, and healthy individuals after arriving at a Quarantine Station in Australia was an effective public health response., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Alahakoon et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

As most disease causing pathogens require transmission from an infectious individual to a susceptible individual, continued persistence of the pathogen within the population requires the replenishment of susceptibles through births, immigration, or waning immunity. Consider the introduction of an unknown infectious disease into a fully susceptible population where it is not known how long immunity is conferred once an individual recovers from infection. If, initially, the prevalence of disease increases (that is, the infection takes off), the number of infectives will usually decrease to a low level after the first major outbreak. During this post-outbreak period, the disease dynamics may be influenced by stochastic effects and there is a non-zero probability that the epidemic will die out. Die out in this period following the first major outbreak is known as an epidemic fade-out. If the disease does not die out, the susceptible population may be replenished by the waning of immunity, and a second wave may start. In this study, we investigate if the rate of waning immunity (and other epidemiological parameters) can be reliably estimated from multiple outbreak data, in which some outbreaks display epidemic fade-out and others do not. We generated synthetic outbreak data from independent simulations of stochastic SIRS models in multiple communities. Some outbreaks faded-out and some did not. We conducted Bayesian parameter estimation under two alternative approaches: independently on each outbreak and under a hierarchical framework. When conducting independent estimation, the waning immunity rate was poorly estimated and biased towards zero when an epidemic fade-out was observed. However, under a hierarchical approach, we obtained more accurate and precise posterior estimates for the rate of waning immunity and other epidemiological parameters. The greatest improvement in estimates was obtained for those communities in which epidemic fade-out was observed. Our findings demonstrate the feasibility and value of adopting a Bayesian hierarchical approach for parameter inference for stochastic epidemic models., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

We describe an experimental setup and a currently running experiment for evaluating how physical interactions over time and between individuals affect the spread of epidemics. Our experiment involves the voluntary use of the Safe Blues Android app by participants at The University of Auckland (UoA) City Campus in New Zealand. The app spreads multiple virtual safe virus strands via Bluetooth depending on the physical proximity of the subjects. The evolution of the virtual epidemics is recorded as they spread through the population. The data is presented as a real-time (and historical) dashboard. A simulation model is applied to calibrate strand parameters. Participants' locations are not recorded, but participants are rewarded based on the duration of participation within a geofenced area, and aggregate participation numbers serve as part of the data. The 2021 experimental data is available as an open-source anonymized dataset, and once the experiment is complete, the remaining data will be made available. This paper outlines the experimental setup, software, subject-recruitment practices, ethical considerations, and dataset description. The paper also highlights current experimental results in view of the lockdown that started in New Zealand at 23:59 on August 17, 2021. The experiment was initially planned in the New Zealand environment, expected to be free of COVID and lockdowns after 2020. However, a COVID Delta strain lockdown shuffled the cards and the experiment is currently extended into 2022., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2022 Asanjarani et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

The influence of the water content in the initial composition on the size of silica particles produced using the Stöber process is well known. We have shown that there are three morphological regimes defined by compositional boundaries. At low water levels (below stoichiometric ratio of water:tetraethoxysilane), very high surface area and aggregated structures are formed; at high water content (>40 wt%) similar structures are also seen. Between these two boundary conditions, discrete particles are formed whose size are dictated by the water content. Within the compositional regime that enables the classical Stöber silica, the structural evolution shows a more rapid attainment of final particle size than the rate of formation of silica supporting the monomer addition hypothesis. The clearer understanding of the role of the initial composition on the output of this synthesis method will be of considerable use for the establishment of reliable reproducible silica production for future industrial adoption., Competing Interests: Compliance with ethical standardsThe authors declare that they have no conflict of interest.

The synthesis, characterisation and crystal structure of D(8) and D(6) cages from the corresponding bis(dialkoxy)methane is reported.

The present study was carried out in order to examine the anticancer properties of two sesquiterpene lactones, millerenolide and thieleanin, isolated from Viguiera sylvatica and Decachaeta thieleana, against cell lines in vitro, and on the growth B16/BL6 melanoma tumors in C57BL/6 mice. Millerenolide and thieleanin showed a similar pattern of cytotoxicity with the greatest effect on viability being evident with A549 human lung cancer cells (IC(50) - 40 and 32 microM respectively), and with the 3T3/HER2 cell line which are 3T3 mouse fibroblasts transfected with the HER2 oncogene (IC(50) - 16 and 28 microM respectively). The parent 3T3 cells and the B16/BL6 mouse melanoma cells were less sensitive to these compounds, with thieleanin showing an IC(50) with B16/BL6 greater than the highest dose tested (203 microM). Treatment with millerenolide (8 mg/kg, i.p. on days 0, 2 and 4 post-inoculation) significantly inhibited the growth of subcutaneous B16/BL6 tumors in C57BL/6 mice, (50% inhibition at day 25, P=0.015), as well as retarding the appearance of detectable tumor (millerenolide - day 15.2+/-0.4 vs control - day 12.8+/-0.5, mean+/-SEM, P=0.011). In contrast, treatment with thieleanin (8 mg/kg every other day up to the day of kill) neither retarded the appearance of the tumor nor its growth.

The use of rolling circle amplification together with the addition of a wild-type control significantly improves the usefulness of phage display methodology as exemplified by the production of silver and platinum nanoparticles.

Biosilicification occurs on a globally vast scale under mild conditions. Although research has progressed in the area of silica biosynthesis, the molecular mechanisms of these interactions are effectively unknown. The natural production of silica in the Tethya aurantia marine sponge, Cylindrotheca fusiformis diatom, and Equisetum telmateia plant appear to be similar. However, the studies were complicated mechanistic queries due to the use of silicic acid analogues. Given these complications, a carefully chosen model study was carried out to test the ability of enzymes to catalyse the formation of molecules with a single siloxane bond during the in vitro hydrolysis and condensation of alkoxysilanes. Our data suggest that homologous lipase and protease enzymes catalyse the formation of siloxane bonds under mild conditions. Non-specific interactions with trypsin promoted the in vitro hydrolysis of alkoxysilanes, while the active site was determined to selectively catalyse the condensation of silanols.

Hexasilsesquioxane cages (T6) have been prepared from a range of alkyl and aryl trichlorosilanes using a "non aqueous" hydrolysis with dimethyl sulfoxide.

Parrondo's games present an apparently paradoxical situation where individually losing games can be combined to win. In this article we analyze the case of two coin tossing games. Game B is played with two biased coins and has state-dependent rules based on the player's current capital. Game B can exhibit detailed balance or even negative drift (i.e., loss), depending on the chosen parameters. Game A is played with a single biased coin that produces a loss or negative drift in capital. However, a winning expectation is achieved by randomly mixing A and B. One possible interpretation pictures game A as a source of "noise" that is rectified by game B to produce overall positive drift-as in a Brownian ratchet. Game B has a state-dependent rule that favors a losing coin, but when this state dependence is broken up by the noise introduced by game A, a winning coin is favored. In this article we find the parameter space in which the paradoxical effect occurs and carry out a winning rate analysis. The significance of Parrondo's games is that they are physically motivated and were originally derived by considering a Brownian ratchet-the combination of the games can be therefore considered as a discrete-time Brownian ratchet. We postulate the use of games of this type as a toy model for a number of physical and biological processes and raise a number of open questions for future research. (c) 2001 American Institute of Physics.