Recent publications
Enhanced catalytic activity of Ni on-Al2O3 and ZSM-5 on addition of ceria zirconia for the partial oxidation of methane, Applied Catalysis B, Environmental http://dx.
Nickel supported on η-Al2O3 and ZSM-5(80) catalysts with and without the addition of ceria-zirconia, were prepared by co-precipitation and wet impregnation methods and used for the low temperature catalytic partial oxidation of methane (CPOM). The catalysts were tested under reaction temperatures of between 400 and 700 °C with a WHSV of 63,000 mL g−1 h−1. The activity of the catalyst was found to be dependent on the support and preparation method. The optimum catalyst composition of those tested was 10% Ni on 25%CeO2-ZrO2/ZSM-5(80), prepared by co-precipitation, where the reaction reached equilibrium conversion at 400 °C (T50% < 400 °C), which is one of the lowest temperatures reported to date. Further increases in temperature led to improved selectivity to CO reaching 60% at 600 °C. Although the observed kinetics were found to be controlled by strong adsorption of CO at lower temperature, this was an equilibrium limitation with longer time on stream experiments showing no decrease in the catalyst activity over 25 hours at 400 °C.
A two‐step one‐pot rapid microwave assisted method has been developed for the Baeyer‐Villiger oxidation of biomass derived levoglucosenone (LGO) analogues. This method uses the acidic resin Amberlyst 15 as the catalyst and hydrogen peroxide as the oxidant in ethanol solution. A small library of C4‐substituted LGO analogues have been synthesised and oxidised using this method giving high yields in short times in each case. The purity of the recovered products was very high removing the need for chromatographic separation.
To tackle global warming, the Paris Agreement (2015) strategically proposed achieving net-zero emissions of greenhouse gases (GHGs) by 2050 and limiting the global temperature rise below 2 °C. This requires a substantial reduction of all GHG emissions across all sectors over the next few decades. Methane has come into the spotlight as the second most potent GHG for its contribution to global warming. The Global Methane Pledge announced at COP26 (2021) proposed to reduce 30% of anthropogenic methane emissions by 2030 compared to the 2020 level. However, studies show that methane emissions will continue to increase even with the planned reductions and therefore the atmospheric methane concentration also. Effective methane removal technologies are urgently required for atmospheric methane remediation. This work evaluates the feasibility of atmospheric methane removal by enhancing the chlorine atom sink (i.e. a natural sink of methane in the lower troposphere) at a significant scale, considering that atomic chlorine initiates methane oxidation 16 times faster than the major natural methane sink of hydroxyl radicals in the atmosphere. Atomic chlorine is proposed to be generated by electrolysis of brine for chlorine gas followed by photolysis. This methane removal technology could be integrated with the state-of-the-art industrial chlor-alkali processes. Such integrated technology is evaluated for the potential of negative GHG emissions and their costs, with attention given to cost-efficient measures, i.e., the use of alternative renewable sources. A brief discussion is included on potential risks, side effects, benefits to the atmospheric methane remediation by 2050 and key required developments.
Considering the rise of far-right groups in Western countries, we examined whether exposure to media coverage on the far-right is associated with attitudes toward it, using surveys in 15 Western democratic countries (total N = 2,576). We hypothesized that greater media exposure to the far-right will be associated with greater perceived prevalence and acceptability of it, which will in turn be associated with divergent attitudes. On the one hand, greater perceived prevalence may be associated with more unfavorable attitudes toward the far-right (a threat response). On the other hand, greater perceived acceptability may be associated with more favorable attitudes toward the far-right (a normalization response). Overall, there was more evidence for a threat response than a normalization response: media exposure was consistently related to greater perceived prevalence (but not acceptability) of the far-right. This research underscores the importance of studying the consequences of the rise of the far-right.
Bacterial adaptation to stress can lead to phenotypic variants with diverse levels of niche competitiveness, pathogenicity, and antimicrobial resistance. In this work, we employed experimental evolution to investigate whether exposure to various stress conditions results in new phenotypic and metabolic properties in clinical and environmental strains of Vibrio cholerae . Our findings revealed the emergence of variants with metabolic and genetic variations and enhanced survival under stress compared to the parental isolates. Phenotypic changes in the evolved variants included colony morphology, biofilm formation, and the appearance of proteolytic and hemolytic activities. The variants demonstrated metabolic changes in the preferred use of carbon, nitrogen, phosphorous, and sulfur substrates, while the genetic changes included single nucleotide polymorphisms (SNPs), breakpoints, translocations, and single nucleotide insertions and deletions. Mutations in genes encoding EAL and HD-GYP domain-containing proteins correlated with increased biofilm formation and different colony morphotypes. The combined analysis of the metabolic and genomic data pointed to pathways implicated in stress survival. The environmental strains were generally more pathogenic than the clinical strains in the Galleria mellonella infection model prior to the experimental evolution, and these differences did not change in the evolved variants. This study highlights the contribution of stress conditions as drivers for the evolution of genetic modifications and metabolic adaptation in V. cholerae , which may explain the continuous evolution of El-Tor biotype strains toward variants with improved survival in the environment.
IMPORTANCE
How Vibrio cholerae , the causative agent of cholera, survives during the periods between outbreaks remains a critical question. Using experimental evolution based on serial bacterial passages in culture media mimicking diverse environmental stress conditions, we investigated whether clinical and environmental isolates of V. cholerae develop changes in survival and in their metabolism. The evolved variants exhibited alterations in colony morphology, biofilm formation, and metabolism, including changes in the preferred use of carbon, nitrogen, phosphorous, and sulfur substrates. These changes were accompanied by various genetic modifications, notably in genes encoding second messenger molecules that regulate multiple biochemical pathways implicated in stress survival and increased pathogenic potential. Our results suggest a continuous evolution of V. cholerae strains toward variants displaying increased survival under environmental stress conditions that may also be encountered in the human host.
Studies of microorganisms in extreme Mars-analog environments have generally overlooked fungi. Here, we document fungi in lake waters, slime, and halite of the acid-saline Lakes Magic and Gneiss in Western Australia with pH 1.4–3.5 and 7–32% total dissolved solids (TDS). Both extremotolerant fungi, including ascomycete Parengyodontium torokii, and relatively common fungi (mesophilic), including Penicillium breviocompactum and Trametes pubescens, were present. Our discovery of P. torokii in halite is among the first known fungal examples of such preservation, and we propose that it has the biological traits of a generalist species. Nine strains of the dominant P. torokii fungi were tested for growth on diverse salts. The presence of mesophilic fungal saprotrophs in these lakes, along with extremophilic fungi, algae, bacteria, and archaea, suggests transport of the former into indigenous lake populations. This reveals a distinction between habitability and preservation potential; not all biosignatures in lake waters or their halite represent organisms that were active in situ. Our results suggest that searches for biosignatures in extreme waters and salt minerals on Earth and Mars should include the possibility of fungi. Additionally, interpretations of microbial communities in both modern brines and the rock record should consider the likelihood of mixed indigenous and transported taxa.
Predator–prey interactions underpin ecological dynamics from population to ecosystem scales, affecting population growth and influencing community stability. One of the classic methods to study these relationships is the functional response (FR) approach, measuring resource use across resource densities.
Global warming is known to strongly mediate consumer–resource interactions, but the relevance of prey and predator densities remains largely unknown. Elevated temperature could increase consumer energy expenditure, which needs to be compensated by greater foraging activity. However, such greater activity may concurrently result in a higher encounter rate with other consumers, which potentially affects their total pressure on resource populations because of synergistic or antagonistic effects among multiple predators.
We performed a laboratory experiment using three densities of a fish predator (pumpkinseed, Lepomis gibbosus) (one, two and four specimens), two temperatures (25 and 28°C) and six prey densities. Using the FR approach, we investigated the combined effects of elevated temperature and predator and prey density on the consumer's foraging efficiency.
We observed a reduced maximum feeding rate at the higher temperature for single predators. However, the foraging efficiency of predators in groups was negatively affected by antagonistic interactions between individuals and further mediated by the temperature. Specifically, we observed a general decrease in antagonistic interactions at elevated compared to the ambient water temperature for multiple predator groupings. Irrespective of temperature, antagonistic multiple predator effects increased with predator density and peaked unimodally at intermediate prey densities, indicating multiple dimensions of density‐dependence that interact to supersede the effects of warming.
This study shows that conspecific presence negatively affects the per capita performance of predators, but that this effect is dampened with increasing temperature. Their adaptive response to temperature consists of limited food intake and further reduced intraspecific interactions. Including intraspecific competition in study design may thus offer more realistic outcomes compared to widely used experiments with only single predator individuals, which could overestimate the effect of increasing temperature.
This article critically examines the concept of resource scarcity within the context of capitalist accumulation and colonial legacies. Employing an ecofeminist approach, it challenges dominant narratives of scarcity that obscure systemic processes of resource deprivation in the global South and care economies. The analysis reveals how the rhetoric of scarcity serves capitalist interests and perpetuates colonial exploitation, leading to unequal resource allocation between productive and reproductive economies, and between the global North and South. Drawing on ecofeminist theory, enriched by decolonial and Marxist critiques, this article argues that resource scarcity is not merely relative within planetary boundaries, but fundamentally a consequence of capitalist modes of production and colonial exploitation of women, racialised populations, and the more-than-human world. Scarcity is artificially manufactured through processes of overaccumulation, overdevelopment, and corporate violence. The article advocates for an ecofeminist decolonial degrowth political economy as a form of climate reparation. This approach explicitly aims to expand the care economy, challenging the growth paradigm and redistributing resources between production and reproduction, and between North and South. It envisions the development of plural, interdependent economies that resist capitalist domination and pave the way for post-capitalist modes of living that prioritise human flourishing and ecological sustainability.
Precisely modulating the chemical microenvironment of catalytic centers at the molecular level to achieve efficient photocatalytic nitrogen fixation remains a grand challenge. Herein, a polyoxometalates (POMs) metalloporphyrin organic framework Fe‐PMOF {POM‐TCPP(Fe)} is constructed by integrating the oxygen‐rich unit POMs {ε‐PMo8VMo4VIO40Zn4} and the photosensitive metalloporphyrin (Fe‐TCPP) as a model to precisely regulate intermolecular electron transfer. Benefiting from electronic interactions, the optimized POM‐TCPP(Fe) exhibits a favorable activity toward NH3 production with a rate of 110.06 µmol g⁻¹ h⁻¹. The improved performance can be attributed to the effective regulation of the chemical microenvironment surrounding the active centers, enabling the synergistic interaction of multiple active sites (Fe and Mo) to facilitate the adsorption and activation of nitrogen. More specifically, oxygen‐rich unit POMs exhibit strong electronegativity, which can attract electrons from Fe atoms, thereby decreasing the 3d orbitals’ electron density of Fe sites and elevating its unoccupied d‐orbitals to facilitate N2 adsorption. Moreover, the porphyrin units with high photosensitivity efficiently generate electrons under photoexcitation, which can rapidly migrate and inject them to the active Fe‐N‐N* sites to facilitate N2 activation. Ultimately, the mimic nitrogenase active site intelligently integrates multiple active sites of transition metals Fe and Mo, thus improving the nitrogen fixation efficiency.
Amidst the dual challenges of aggregate scarcity and the environmental impact of carbon dioxide (CO2) emissions from cement production, this study investigates the viability of palm oil clinker (POC) as a sustainable aggregate in geopolymer concrete (GPC). The lack of appropriate alternative coarse and fine aggregates essential in concrete production is one of the critical issues faced by the construction industry. This review evaluates its environmental benefits, chemical and physical attributes, and influence on GPC's microstructure. Previous studies have shown that incorporating POC in GPC significantly reduces density from 2345 to 1821 kg/m³ while maintaining competitive compressive strength, thus proving its applicability in various structural and nonstructural contexts. Moreover, GPC with POC demonstrates enhanced resistance to aggressive environmental conditions such as water absorption and resistance against acid and sulfate environments. Geopolymer mortar (GPM) exposed to sulfate attack recorded the lowest decrease in strength than GPM containing POC fine aggregates by about 20%. The use of 100% POC aggregates in GPC mix has a 3.2% water absorption, which is lower than the limit for high‐performance concrete. The results advocate for the development of POC‐aggregate GPC as an environmentally friendly construction material, contributing to the sustainable advancement of the building industry.
In this chapter, we present recommendations for change written by the project's peer researchers, based on their findings from the study. During qualitative interviews, the peers discussed with sex workers how services should change and what actions could be taken to bring about this change. The peer researchers then discussed potential changes in action learning sets, a problem-solving process explained in detail in Chapter 9 . Their personal experiences as sex workers and/or practitioners in the field gave them a deep understanding of the challenges that sex workers face. Their analysis followed an action research approach and aligned with the trauma-informed design of the project.
There are numerous modes of anesthesia from which an eye surgeon can choose. Overall, there is not one type of anesthesia that is right for all cases. The best choice varies from surgeon to surgeon and from patient to patient. As cataract removal has become faster, safer, and less traumatic, the need for akinesia and anesthesia has declined significantly, and the use of general anesthesia or regional (i.e., retrobulbar or peribulbar) block has largely been replaced with other safer and equally effective means of local anesthesia including sub-Tenon’s block, subconjunctival, intracameral, and topical, the latter being the most used technique. These newer and less invasive methods have not only reduced the potential for catastrophic surgical complications but also increased the efficiency of cataract surgery (as there is probably no need for anesthetic team support) and hastened the process of visual rehabilitation.
The goal of this chapter is to review the current choices for local ocular anesthesia in patients with glaucoma undergoing cataract surgery, helping to select the most appropriate type of anesthesia for each patient.
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