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•Quantum yields of losartan potassium in water are reported for the first time.•UV-C photolysis enabled 90% removal of furosemide in water within 870 mJ cm−2.•Mineralization of target ...compounds was higher under UV-C/S2O82−.•UV-C/H2O2 was more efficient on the removal of toxicity than UV-C/S2O82−.•A degradation pathway for caffeine degradation via UV-C/H2O2 is proposed.
In this study, the degradation of four emerging contaminants losartan potassium (LP), furosemide (FRSM), caffeine (CAF), and carbendazim (CBZ) under UV-C, UV-C/H2O2, and UV-C/S2O82− was investigated. A comparative evaluation of the efficiency of UV-C/H2O2 and UV-C/S2O82− in the degradation of these target CECs has not yet been reported. Moreover, target compounds were submitted to UV-C/AOPs individually in pure water and their simultaneous degradation was investigated in real surface water. Evolution of the acute toxicity of each compound during treatment was evaluated using Alivibrio fischeri. Quantum yields were determined for LP (0.011–0.016), FRSM (0.024–0.092), CAF (0.0007–0.0009), and CBZ (0.0016–0.0036) at different pH values. UV-C/H2O2 and UV-C/S2O82 achieved more than 98% removal of all compounds within 600 mJ cm−2, and pseudo-fist-order kinetic constants (k′app) for the degradation reactions were up to seven times higher in the presence of these oxidants when compared to k′app values obtained for UV-C photolysis. k′app measured for UV-C/H2O2 were higher than those calculated for UV-C/S2O82− except in the case of LP. Acute toxicity analysis suggested the formation of toxic intermediates during the UV-C photolysis of LP and FRSM, and the degradation of LP via UV-C/S2O82− also enhanced acute toxicity although electric energy efficiency per order identified UV-C/S2O82 as the most efficient process for the removal of this compound. Finally, different transformation products obtained during the degradation of caffeine under the different UV-C AOPs suggested that distinct degradation routes were involved in each treatment tested.
Partial reduction of ceria generates catalytically active bridging OH groups on the surface of ceria. Pt facilitates this surface reduction process, and in this work, the impact of the Pt promoter ...loading on catalyst structural-property relationships was explored. XANES spectra were recorded under H
2 treatment for a series of Pt/ceria catalysts with increasing Pt loading at both the Pt and Ce
L
III
edges. Reduction of Pt oxide was hindered by metal–support interactions, such that higher Pt loadings facilitated reduction of Pt oxide to Pt
0. Two routes of bridging OH group formation are as follows: (1) once it is reduced, Pt
0 dissociates H
2, which spills over to the ceria surface to generate the bridging OH group active sites directly, accompanied by a change in the oxidation state of the Ce atoms involved with the sites from Ce
4+ to Ce
3+; and (2) H
2 or CO removes ceria surface capping oxygen atoms to generate vacancies (and surface Ce
3+), followed by H
2O dissociation at the vacancies to generate the bridging OH groups. Either route highlights the direct link between the extent of ceria partial reduction and the active site density of the bridging OH group active sites. The relative Ce
3+ and Ce
4+ concentrations from XANES were quantified and at low temperature; the greatest degree of ceria reduction was obtained for the Pt/ceria catalysts with higher Pt loadings, correlating with a higher bridging OH group active site density. Using in situ DRIFTS, we used CO as a probe molecule, as it reacts with the bridging OH groups to generate surface formates, the proposed intermediates of the WGS reaction. While addition of CO to the unpromoted catalyst reduced at 250 °C led to only very weak formate bands due to a lack of bridging OH groups on the ceria surface at that temperature, strong formate bands arose on the surface of the Pt/ceria catalysts at 250 °C. In situ DRIFTS was also utilized to probe the dynamics of the surface formate coverages under low-temperature WGS reaction conditions over the Pt/ceria series. A high H
2O/CO feed ratio was employed, and the surface formate coverages were found to be more limited by the WGS rate for the heavily loaded Pt/ceria catalysts. This indicates that Pt may not only serve to facilitate the generation of the bridging OH group active sites at low temperature, but may also be involved in accelerating surface formate decomposition, the elementary step of the mechanism that is proposed to be rate limiting. A clear trend of higher CO conversion with higher Pt loading was established in reaction testing. HR-TEM carried out on the 5%Pt/ceria catalyst indicated well-dispersed Pt clusters in the diameter range of 1–2 nm.
Segregation and templating approaches have been honed by billions of years of evolution to direct many complex biological processes. Nature uses segregation to improve biochemical control by ...organizing reactants into defined, well-regulated environments, and the transfer of genetic information is a primary function of templating. The ribosome, wherein messenger RNA is translated into polypeptides, combines both techniques to allow for ideal biopolymer syntheses. Herein is presented a biomimetic segregation/templating approach to synthetic radical polymerization. Polymerization of a nucleobase-containing vinyl monomer in the presence of a complementary block copolymer template of low molecular weight yields high molecular weight (M(w) up to ~400,000 g mol(-1)), extremely low polydispersity (≤1.08) daughter polymers. Control is attained by segregation of propagating radicals in discrete micelle cores (via cooperative assembly of dynamic template polymers). Significantly reduced bimolecular termination, combined with controlled propagation along a defined number of templates, ensures unprecedented control to afford well-defined high molecular weight polymers.
Metal–organic frameworks (MOFs) have emerged as a versatile platform for the rational design of multifunctional materials, combining large specific surface areas with flexible, periodic frameworks ...that can undergo reversible structural transitions, or “breathing”, upon temperature and pressure changes, and through gas adsorption/desorption processes. Although MOF breathing can be inferred from the analysis of adsorption isotherms, direct observation of the structural transitions has been lacking, and the underlying processes of framework reorganization in individual MOF nanocrystals is largely unknown. In this study, we describe the characterization and elucidation of these processes through the combination of in situ environmental transmission electron microscopy (ETEM) and computer simulations. This combined approach enables the direct monitoring of the breathing behavior of individual MIL-53(Cr) nanocrystals upon reversible water adsorption and temperature changes. The ability to characterize structural changes in single nanocrystals and extract lattice level information through in silico correlation provides fundamental insights into the relationship between pore size/shape and host–guest interactions.
The skin is inhabited by a multitude of microorganisms. An imbalance of these microorganisms is associated with disease, however, the causal relationship between skin microbiota and disease remains ...unknown. To describe the cutaneous bacterial microbiota of cats and determine whether bacterial dysbiosis occurs on the skin of allergic cats, the skin surfaces on various regions of 11 healthy cats and 10 allergic cats were sampled.
Genomic DNA was extracted from skin swabs and sequenced using primers that target the V4 region of the bacterial 16S rRNA. The bacterial sequences from healthy cats revealed that there are differences in species diversity and richness between body sites and different epithelial surfaces. Bacterial communities preferred body site niches in the healthy cats, however, the bacterial communities on allergic cat skin tended to be more unique to the individual cat. Overall, the number of bacterial species was not significantly different between the two health status groups, however, the abundances of these bacterial species were different between healthy and allergic skin. Staphylococcus, in addition to other taxa, was more abundant on allergic skin.
This study reveals that there are more bacterial species inhabiting the skin of cats than previously thought and provide some evidence of an association between dysbiosis and skin disease.
Background
The public safety sector includes law enforcement officers (LEO), corrections officers (CO), firefighter service (FF), wildland firefighting (WFF), and emergency medical services (EMS), as ...defined in the National Occupational Research Agenda (NORA) of the National Institute for Occupational Safety and Health (NIOSH). Across these occupations, shiftwork, long‐duration shifts, and excessive overtime are common. Our objective was to identify research gaps related to working hours, sleep, and fatigue among these workers.
Methods
We used a scoping review study design that included searches of MEDLINE, Embase, CAB s, Global Health, PsychInfo, CINAHL, Scopus, Academic Search Complete, Agricultural and Environmental Science Collection, ProQuest Central, Cochrane Library, Safety Lit, Homeland Security Digital Library, and Sociological s using a range of occupational search terms and terms related to working hours, sleep, and fatigue.
Results
Out of 3415 articles returned from our database search, 202 met all inclusion criteria. Six common outcomes related to working hours, sleep, and fatigue emerged: sleep, fatigue, work performance, injury, psychosocial stress, and chronic disease. Nearly two‐thirds (59%, n = 120) of the studies were observational, of which 64% (n = 77) were cross sectional and 9% were (n = 11) longitudinal; 14% (n = 30) of the studies were reviews; and 19% (n = 39) were experimental or quasi‐experimental studies. Only 25 of the 202 articles described mitigation strategies or interventions. FFs, LEOs, EMS, and WFFs were the most studied, followed by COs.
Conclusions
In general, more longitudinal and experimental studies are needed to enrich the knowledge base on the consequences of long working hours, poor sleep, and fatigue in the public safety sector. Few experimental studies have tested novel approaches to fatigue mitigation in diverse sectors of public safety. This gap in research limits the decisions that may be made by employers to address fatigue as a threat to public‐safety worker health and safety.
Postsynthetic strategies for modifying metal–organic frameworks (MOFs) have proven to be an incredibly powerful approach for expanding the scope and functionality of these materials. Previously, we ...reported on the postsynthetic exchange (PSE) of metal ions and ligands in the University of Oslo (UiO) series of MOFs. Detailed characterization by several analytical methods, most notably inductively coupled plasma mass spectrometry and transmission electron microscopy reveal that metal ion deposition on the surface of these MOFs occurs in the form of nanoscale metal oxides, rather than yielding exchanged metal sites within the MOFs, as was previously reported. By contrast, these combined analytical methods do confirm that ligand-based PSE can occur in these MOFs. These findings provide new insight into the postsynthetic manipulation of MOF materials, highlight the importance of rigorously characterizing these materials to correctly assign their composition and structure, and provide a new route to making hybrid solids with a MOF@metal oxide architecture.
The effect of covalently attaching 4-(dimethylamino)pyridine (DMAP) functionality to the hydrophobic core of a polymeric micelle in water has been investigated in the context of acylation reactions ...employing non-water-soluble substrates. For this purpose a novel temperature-responsive polymeric micelle has been synthesized using reversible addition–fragmentation chain transfer (RAFT) polymerization techniques. The reactivity of the tethered organocatalyst within the nanostructure was found to be extremely high, improving in some cases the acylation rates up to 100 times compared to those for unsupported DMAP in organic solvents. Moreover, the catalytic nanoreactors have been demonstrated to be capable of reuse up to 6 times while maintaining high activity.
Changes in the microbial populations on the skin of animals have traditionally been evaluated using conventional microbiology techniques. The sequencing of bacterial 16S rRNA genes has revealed that ...the human skin is inhabited by a highly diverse and variable microbiome that had previously not been demonstrated by culture-based methods. The goals of this study were to describe the microbiome inhabiting different areas of the canine skin, and to compare the skin microbiome of healthy and allergic dogs.
DNA extracted from superficial skin swabs from healthy (n = 12) and allergic dogs (n = 6) from different regions of haired skin and mucosal surfaces were used for 454-pyrosequencing of the 16S rRNA gene. Principal coordinates analysis revealed clustering for the different skin sites across all dogs, with some mucosal sites and the perianal regions clustering separately from the haired skin sites. The rarefaction analysis revealed high individual variability between samples collected from healthy dogs and between the different skin sites. Higher species richness and microbial diversity were observed in the samples from haired skin when compared to mucosal surfaces or mucocutaneous junctions. In all examined regions, the most abundant phylum and family identified in the different regions of skin and mucosal surfaces were Proteobacteria and Oxalobacteriaceae. The skin of allergic dogs had lower species richness when compared to the healthy dogs. The allergic dogs had lower proportions of the Betaproteobacteria Ralstonia spp. when compared to the healthy dogs.
The study demonstrates that the skin of dogs is inhabited by much more rich and diverse microbial communities than previously thought using culture-based methods. Our sequence data reveal high individual variability between samples collected from different patients. Differences in species richness was also seen between healthy and allergic dogs, with allergic dogs having lower species richness when compared to healthy dogs.
In a subset of children experiencing prolonged febrile seizures (FSs), the most common type of childhood seizures, cognitive outcomes are compromised. However, the underlying mechanisms are unknown. ...Here we identified significant, enduring spatial memory problems in male rats following experimental prolonged FS (febrile status epilepticus; eFSE). Remarkably, these deficits were abolished by transient,
interference with the chromatin binding of the transcriptional repressor neuron restrictive silencing factor (NRSF or REST). This transcriptional regulator is known to contribute to neuronal differentiation during development and to programmed gene expression in mature neurons. The mechanisms of the eFSE-provoked memory problems involved complex disruption of memory-related hippocampal oscillations recorded from CA1, likely resulting in part from impairments of dendritic filtering of cortical inputs as well as abnormal synaptic function. Accordingly, eFSE provoked region-specific dendritic loss in the hippocampus, and aberrant generation of excitatory synapses in dentate gyrus granule cells. Blocking NRSF transiently after eFSE prevented granule cell dysmaturation, restored a functional balance of γ-band network oscillations, and allowed treated eFSE rats to encode and retrieve spatial memories. Together, these studies provide novel insights into developing networks that underlie memory, the mechanisms by which early-life seizures influence them, and the means to abrogate the ensuing cognitive problems.
Whereas seizures have been the central focus of epilepsy research, they are commonly accompanied by cognitive problems, including memory impairments that contribute to poor quality of life. These deficits often arise before the onset of spontaneous seizures, or independent from them, yet the mechanisms involved are unclear. Here, using a rodent model of common developmental seizures that provoke epilepsy in a subset of individuals, we identify serious consequent memory problems. We uncover molecular, cellular, and circuit-level mechanisms that underlie these deficits and successfully abolish them by targeted therapeutic interventions. These findings may be important for understanding and preventing cognitive problems in individuals suffering long febrile seizures.
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