Showing papers by "Michael R. Hoffmann published in 2019"

Activation of Peroxymonosulfate by Oxygen Vacancies-Enriched Cobalt-Doped Black TiO2 Nanotubes for the Removal of Organic Pollutants

Abstract: Cobalt-mediated activation of peroxymonosulfate (PMS) has been widely investigated for the oxidation of organic pollutants. Herein, we employ cobalt-doped Black TiO_2 nanotubes (Co-Black TNT) for the efficient, stable, and reusable activator of PMS for the degradation of organic pollutants. Co-Black TNTs induce the activation of PMS by itself and stabilized oxygen vacancies that enhance the bonding with PMS and provide catalytic active sites for PMS activation. A relatively high electronic conductivity associated with the coexistence of Ti^(4+) and Ti^(3+) in Co-Black TNT enables an efficient electron transfer between PMS and the catalyst. As a result, Co-Black TNT is an effective catalyst for PMS activation, leading to the degradation of selected organic pollutants when compared to other TNTs (TNT, Co-TNT, and Black TNT) and other Co-based materials (Co_3O_4, Co-TiO_2, CoFe_2O_4, and Co_3O_4/rGO). The observed organic compound degradation kinetics are retarded in the presence of methanol and natural organic matter as sulfate radical scavengers. These results demonstrate that sulfate radical is the primary oxidant generated via PMS activation on Co-Black TNT. The strong interaction between Co and TiO_2 through Co–O–Ti bonds and rapid redox cycle of Co^(2+)/Co^(3+) in Co-Black TNT prevents cobalt leaching and enhances catalyst stability over a wide pH range and repetitive uses of the catalyst. Electrode-supported Co-Black TNT facilitates the recovery of the catalyst from the treated water.

Measuring Terrestrial Area of Habitat (AOH) and Its Utility for the IUCN Red List.

Abstract: The International Union for Conservation of Nature (IUCN) Red List of Threatened Species includes assessment of extinction risk for 98 512 species, plus documentation of their range, habitat, elevation, and other factors. These range, habitat and elevation data can be matched with terrestrial land cover and elevation datasets to map the species' area of habitat (AOH; also known as extent of suitable habitat; ESH). This differs from the two spatial metrics used for assessing extinction risk in the IUCN Red List criteria: extent of occurrence (EOO) and area of occupancy (AOO). AOH can guide conservation, for example, through targeting areas for field surveys, assessing proportions of species' habitat within protected areas, and monitoring habitat loss and fragmentation. We recommend that IUCN Red List assessments document AOH wherever practical.

CO2, water, and sunlight to hydrocarbon fuels: a sustained sunlight to fuel (Joule-to-Joule) photoconversion efficiency of 1%

Abstract: If we wish to sustain our terrestrial ecosphere as we know it, then reducing the concentration of atmospheric CO2 is of critical importance. An ideal pathway for achieving this would be the use of sunlight to recycle CO2, in combination with water, into hydrocarbon fuels compatible with our current energy infrastructure. However, while the concept is intriguing such a technology has not been viable due to the vanishingly small CO2-to-fuel photoconversion efficiencies achieved. Herein we report a photocatalyst, reduced blue-titania sensitized with bimetallic Cu–Pt nanoparticles that generates a substantial amount of both methane and ethane by CO2 photoreduction under artificial sunlight (AM1.5): over a 6 h period 3.0 mmol g−1 methane and 0.15 mmol g−1 ethane are obtained (on an area normalized basis 0.244 mol m−2 methane and 0.012 mol m−2 ethane), while no H2 nor CO is detected. This activity (6 h) translates into a sustained Joule (sunlight) to Joule (fuel) photoconversion efficiency of 1%, with an apparent quantum efficiency of φ = 86%. The time-dependent photoconversion efficiency over 0.5 h intervals yields a maximum value of 3.3% (φ = 92%). Isotopic tracer experiments confirm the hydrocarbon products originate from CO2 and water.

Multiphase Porous Electrochemical Catalysts Derived from Iron-Based Metal-Organic Framework Compounds.

Abstract: Herbicide use has attracted attention recently due to potential damage to human health and lethality to the honey bees and other pollinators. Fenton reagent treatment processes can be applied for the degradation of herbicidal contaminants from water. However, the need to carry out the normal Fenton reactions under acidic conditions often hinders their practical application for pollution control. Herein, we report on the synthesis and application of multiphasic porous electro-Fenton catalysts prepared from calcinated metal–organic framework compounds, CMOF@PCM, and their application for the mineralization of herbicides in aqueous solution at circum-neutral pH. CMOF nanoparticles (NPs) are anchored on porous carbon monolithic (PCM) substrates, which allow for binder-free application. H_2O_2 is electrochemically generated on the PCM substrate which serves as a cathode, while ·OH is generated by the CMOF NPs at low applied potentials (−0.14 V). Results show that the structure and reactivity of the CMOF@PCM electro-Fenton catalysts are dependent on the specific MOF precursor used during synthesis. For example, CMIL-88-NH_2, which is prepared from MIL-88(Fe)–NH_2, is a porous core–shell structured NP comprised of a cementite (Fe_3C) intermediate layer that is sandwiched between a graphitic shell and a magnetite (Fe_3O_4) core. The electro-Fenton production of hydroxyl radical on the CMOF@PCM composite material is shown to effectively degrade an array of herbicides.

Digital Loop-Mediated Isothermal Amplification on a Commercial Membrane.

Abstract: In this work, we report digital loop-mediated isothermal amplification (LAMP) or reverse-transcription LAMP (RT-LAMP) on a commercial membrane, without the need for complex chip fabrication or use of specialized equipment. Due to the pore size distribution, the theoretical error for digital LAMP on these membranes was analyzed, using a combination of Random Distribution Model and Multivolume Theory. A facile peel-off process was developed for effective droplet formation on the commercial track-etched polycarbonate (PCTE) membrane. Each pore functions as an individual nanoreactor for single DNA amplification. Absolute quantification of bacteria genomic DNA was realized with a dynamic range from 11 to 1.1 × 105 copies/μL. One-step digital RT-LAMP was also successfully performed on the membrane for the quantification of MS2 virus in wastewater. With the introduction of new probes, the positive pores can be easily distinguished from negative ones with 100 times difference in fluorescence intensities. Finally, the cost of a disposable membrane is less than $0.10/piece, which, to the best of our knowledge, is the most inexpensive way to perform digital LAMP. The membrane system offers opportunities for point-of-care users or common laboratories to perform digital quantification, single cell analysis, or other bioassays in an inexpensive, flexible, and simplified way.

Enhancing the activity of oxygen-evolution and chlorine-evolution electrocatalysts by atomic layer deposition of TiO2.

Abstract: We report that TiO2 coatings formed via atomic layer deposition (ALD) may tune the activity of IrO2, RuO2, and FTO for the oxygen-evolution and chlorine-evolution reactions (OER and CER). Electrocatalysts exposed to ∼3–30 ALD cycles of TiO2 exhibited overpotentials at 10 mA cm−2 of geometric current density that were several hundred millivolts lower than uncoated catalysts, with correspondingly higher specific activities. For example, the deposition of TiO2 onto IrO2 yielded a 9-fold increase in the OER-specific activity in 1.0 M H2SO4 (0.1 to 0.9 mA cmECSA−2 at 350 mV overpotential). The oxidation state of titanium and the potential of zero charge were also a function of the number of ALD cycles, indicating a correlation between oxidation state, potential of zero charge, and activity of the tuned electrocatalysts.

Using historical and palaeoecological data to inform ambitious species recovery targets.

Abstract: Historical data are a valuable resource for addressing present-day conservation issues, for example by informing the establishment of appropriate recovery targets. However, while the recovery of threatened species is the end goal of many conservation programmes, data made available through the efforts of palaeoecologists and historical ecologists are rarely consulted. The proposal of a 'Green List of Species' by the International Union for Conservation of Nature (IUCN) will soon change this. The Green List of Species measures recovery against historical baselines; in particular, the method requires estimates of species range and abundance in previous centuries. In this paper, we present the case for why setting species recovery against a historical baseline is necessary to produce ambitious conservation targets, and we highlight examples from palaeoecology and historical ecology where fossil and archival data have been used to establish historical species baselines. Finally, we introduce Conservation Archive (https://conservationarchive.shinyapps.io/ConservationArchive/), a database of resources that can be used to infer baseline species conditions, and invite contributions to this database. This article is part of a discussion meeting issue 'The past is a foreign country: how much can the fossil record actually inform conservation?'

Unshifting the baseline: a framework for documenting historical population changes and assessing long-term anthropogenic impacts

Abstract: Ecological baselines—reference states of species' distributions and abundances—are key to the scientific arguments underpinning many conservation and management interventions, as well as to the pub...

Membrane-separated electrochemical latrine wastewater treatment

Abstract: Electrolysis is demonstrated to be useful for onsite latrine wastewater treatment. Improved wastewater treatment efficiencies are achieved through the use of a combination of cation and anion exchange membranes (CEM/AEM) in electrochemical reactors. Compared to a membrane-free electrolysis cell, the separation of anodic and cathodic chambers using a CEM separator is shown to reduce energy consumption by 51% for COD removal and 87% for NH_4+ removal. Furthermore, 51% of the initial [NH_4+]_0 is recovered via electrodialysis. CEM-separated electrolysis is shown to produce 39% less ClO_3− and 92% less chlorinated organic by-products than in a membrane-free reactor. Helminth (Ascaris suum) eggs, which yield parasitic worms, are very resistant to conventional disinfection methods. Membrane-free electrolysis only inactivates 15% of the dosed helminth eggs (100 eggs per mL). In CEM-separated electrolysis, a combination of low pH and in situ chlorine production in the anodic chamber results in 85% inactivation of helminth eggs. In addition, H_2, which is produced in the cathodic chamber of the CEM-separated reactor, is directly converted to electricity using a hydrogen–air fuel cell. The hydrogen energy produced during electrolysis is estimated to reduce the overall energy cost of operation by 20%. Recovery of 85% of the initial [PO_4^3−]_0 and pH neutralization are achieved by treating the acidic effluent of a CEM-separated electrolysis cell in an AEM-separated electrolysis cell. A one-month continuous operation demonstrates the potential of using both the CEM and AEM during electrolysis to achieve more efficient wastewater treatment while, at the same time, recovering NH_4+ and PO_4^3−, for eventual use as agricultural fertilizers.

High-Efficiency Solar Desalination Accompanying Electrocatalytic Conversions of Desalted Chloride and Captured Carbon Dioxide

Abstract: The sustainability of conventional water- and energy-associated systems is being examined in terms of water–energy nexus. This study presents a high-efficiency, off-grid solar desalination system f...

Finite-pulse waves for efficient suppression of evolving mesoscale dendrites in rechargeable batteries.

Abstract: The ramified and stochastic evolution of dendritic microstructures has been a major issue on the safety and longevity of rechargeable batteries, particularly for the utilization of high-energy metallic electrodes. We analytically develop criteria for the pulse characteristics leading to the effective halting of the ramified electrodeposits grown during extensive timescales beyond inter-ionic collisions. Our framework is based on the competitive interplay between diffusion and electromigration and tracks the gradient of ionic concentration throughout the entire cycle of pulse-rest as a critical measure for heterogeneous evolution. In particular, the framework incorporates the Brownian motion of the ions and investigates the role of the geometry of the electrodeposition interface. Our experimental observations verify the analytical developments, where the dimension-free developments allows the application to the electrochemical systems of various scales.

A framework to measure the wildness of managed large vertebrate populations

Abstract: As landscapes continue to fall under human influence through habitat loss and fragmentation, fencing is increasingly being used to mitigate anthropogenic threats and enhance the commercial value of wildlife. Subsequent intensification of management potentially erodes wildness by disembodying populations from landscape-level processes, thereby disconnecting species from natural selection. Tools are needed to measure the degree to which populations of large vertebrate species in formally protected and privately owned wildlife areas are self-sustaining and free to adapt. We devised a framework to measure such wildness based on 6 attributes relating to the evolutionary and ecological dynamics of vertebrates (space, disease and parasite resistance, exposure to predation, exposure to limitations and fluctuations of food and water supply, and reproduction). For each attribute, we set empirical, species-specific thresholds between 5 wildness states based on quantifiable management interventions. We analysed data from 205 private wildlife properties with management objectives spanning ecotourism to consumptive utilization to test the framework on 6 herbivore species representing a range of conservation statuses and commercial values. Wildness scores among species differed significantly, and the proportion of populations identified as wild ranged from 12% to 84%, which indicates the tool detected site-scale differences both among populations of different species and populations of the same species under different management regimes. By quantifying wildness, this framework provides practitioners with standardized measurement units that link biodiversity with the sustainable use of wildlife. Applications include informing species management plans at local scales; standardizing the inclusion of managed populations in red-list assessments; and providing a platform for certification and regulation of wildlife-based economies. Applying this framework may help embed wildness as a normative value in policy and mitigate the shifting baseline of what it means to truly conserve a species.

Criteria for CITES species protection

Abstract: ![Figure][1] Although the red pencilfish is listed as critically endangered and threatened by trade, it is not listed in CITES. PHOTO: BRUNO CAVIGNAUX/BIOSPHOTO/ALAMY STOCK PHOTO Unsustainable international wildlife trade is a major conservation concern, and the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) is a key tool for regulating it. In their Policy Forum “Long delays in banning trade in threatened species” (15 February, p. 686), E. G. Frank and D. S. Wilcove suggest that when the International Union for Conservation of Nature (IUCN) Red List of Threatened Species identifies a species as threatened, at least in part by international trade, it should be promptly added to CITES. The authors claim that 271 such species warrant inclusion in CITES Appendix I or II, which they characterize as a backlog in need of clearing. We welcome the suggestion for closer interaction between the Red List and amendments to the CITES Appendices. However, the proposed approach of a near-automatic pathway overlooks the independent criteria and processes used for evaluating extinction risk on the Red List and for including species in CITES. ![Figure][1] Many pangolin species were upgraded to the more urgent CITES rating only after risk from trade had rapidly increased. PHOTO: [ISTOCK.COM][2]/2630BEN The Red List uses objective categories and criteria with quantitative thresholds (such as population size and trends) and information on known or likely threats ([ 1 ][3]). Conversely, the listing of species under CITES, a legally binding multilateral agreement, is a matter for its 183 parties. CITES uses detailed biological and trade criteria to evaluate proposals for species inclusion in its Appendices, and proposals can only be submitted by parties ([ 2 ][4]). Crucially, species threatened on the Red List that can be linked to international trade may not meet the criteria for inclusion in CITES, particularly when international trade is not a major threat. We agree that new or updated Red List assessments should be shared promptly with the CITES parties, but only subsequent evaluation of species against the CITES listing criteria can determine whether they are added. 1. [↵][5]IUCN Standards and Petitions Subcommittee, “Guidelines for using the IUCN Red List categories and criteria, version 13 (2017); . 2. [↵][6]CITES, Res. Conf. 9.24 (Rev. CoP17), Criteria for amendment of Appendices I and II ( ). [1]: pending:yes [2]: http://ISTOCK.COM [3]: #ref-1 [4]: #ref-2 [5]: #xref-ref-1-1 "View reference 1 in text" [6]: #xref-ref-2-1 "View reference 2 in text"

Giant pangolin Smutsia gigantea (Illiger, 1815)

Abstract: The giant pangolin (Smutsia gigantea) is the largest of all living pangolins, approaching a total length of 180 cm and a weight of more than 30 kg. The species is widely distributed in West and Central Africa in a variety of habitats, including primary and secondary forest, swamp forest and wooded savanna, ranging from Senegal to western Tanzania south to central Democratic Republic of the Congo. Primarily solitary and nocturnal, giant pangolins use their large muscular forelimbs to open subterranean termitaries in contrast to Temminck’s pangolin (S. temminckii) which do little digging. Available data suggest the species is uncommon and declining in many parts of its range, with no recent data for several countries from which it has been previously recorded. Despite their presence in many protected areas and international trade controls, hunting and poaching for bushmeat and international trade remains the primary threat to the species.

Iodide Accelerates the Processing of Biogenic Monoterpene Emissions on Marine Aerosols

Abstract: Marine photosynthetic organisms emit organic gases, including the polyolefins isoprene (C5H8) and monoterpenes (MTPs, C10H16), into the boundary layer. Their atmospheric processing produces particl...

The status of wild canids (Canidae, Carnivora) in Vietnam

Abstract: Four species of wild canids are documented as occurring in Vietnam: Dhole Cuon alpinus, Eurasian Golden Jackal Canis aureus, Red Fox Vulpes vulpes and Raccoon Dog Nyctereutes procyonoides. Except for Dhole, all species are widely distributed globally and are listed as Least Concern on the IUCN Red List of Threatened Species. Concerned by the paucity of recent records of these species from Vietnam, especially in the context of rapidly declining mammal populations in the country in general, we undertook a review of the status of these species in Vietnam. All traceable and potentially verifiable canid records from 01 January 2002 until 31 December 2018 were collated and reviewed. The Dhole, formerly the most widely distributed of all canid species in Vietnam, and Raccoon Dog, apparently formerly widely distributed in the northern part of the country, appear to have both declined; Dhole is now either extirpated, or close to extirpation, while Raccoon Dog is of uncertain status. The Eurasian Golden Jackal does not seem to have been reliably observed in the wild since 2004, although it is possible the species may persist in some areas. Red Fox has only ever been known from a handful of records, and the current status of this species is unknown. In summary, Vietnam cannot be considered to sustain healthy populations of any of its four native wild canid species. These declines seem largely attributable to hunting of both the canids themselves and, for Dhole, their prey base, exacerbated by habitat loss.

Electrolysis electrode featuring metal-doped nanotube array and methods of manufacture and using same

Abstract: An electrolysis electrode includes a metal-doped array of nanotubes formed on a substrate The nanotube array (NTA) may be a stabilized metal-doped black TiO2 NTA formed on a titanium substrate, and the metal dopant may include any suitable metal, for example, cobalt The metal dopant improves the reactivity of the electrode and enhances its service life The metal-doped NTA electrode may provide improved chlorine evolution and/or oxygen evolution activity for electrochemical wastewater treatment The electrode may also be useful for water splitting applications Increasing the loading of the metal dopant may lead to the formation of a metal oxide layer on top of the NTA, which improves oxygen evolution reaction (OER) overpotential

Global priorities for conservation of reptilian phylogenetic diversity in the face of human impacts

Abstract: Phylogenetic Diversity (PD) is increasingly recognised as an important measure that can provide information on evolutionary and functional aspects of biodiversity for conservation planning that are not readily captured by species diversity. Here we develop and analyse two new metrics that combine the effects of PD and human encroachment on species range size — one metric valuing regions and another enabling species prioritisation. We evaluate these metrics for reptiles, which have been largely neglected in previous studies, and contrast these results with equivalent calculations for all terrestrial vertebrate groups. We find that high human impacted areas unfortunately coincide with the most valuable areas of reptilian diversity, more than expected by chance. We also find that, under our species-level metric, the highest priority reptile species score far above the top mammal and bird species, and they include a disproportionate number of species with insufficient information on potential threats. Such Data Deficient species are, in terms of our metric, comparable to Critically Endangered species and may require urgent conservation attention.

On detecting changes in the jumps of arbitrary size of a time-continuous stochastic process

Abstract: This paper introduces test and estimation procedures for abrupt and gradual changes in the entire jump behaviour of a discretely observed Itō semimartingale. In contrast to existing work we analyse jumps of arbitrary size which are not restricted to a minimum height. Our methods are based on weak convergence of a truncated sequential empirical distribution function of the jump characteristic of the underlying Itō semimartingale. Critical values for the new tests are obtained by a multiplier bootstrap approach and we investigate the performance of the tests also under local alternatives. An extensive simulation study shows the finite-sample properties of the new procedures.

Loop-mediated isothermal amplification (lamp) based assay for detecting microbes

Abstract: A method and system are disclosed for detecting microbial pathogens in a sample suspected of containing the pathogens. The method includes combining loop-mediated isothermal amplification (LAMP) reagents and a polymer gel, such as a hydrogel, together with the sample to form a mixture. The gel polymerizes over a short time to immobilize the viral particles within the mixture. If target DNA/RNA are present in the sample, amplicons are produced. The target microorganisms are detected by visually detecting the presence or absence of the amplicons. The target microorganism concentrations may be determined based on the number of fluorescent amplicon dots after the reaction using a smartphone or a fluorescent microscope. The method may be employed for rapidly and inexpensively quantifying microbial pathogens in environmental water samples with high sensitivity.

Portable pathogen analysis system for detecting waterborne pathogens

Abstract: A portable pathogen analysis system (PPAS) designed to detect microbial pathogens at the point-of-sample collection. The system comprises a concentration tube used for the concentration of microbes in large volumes of water samples using super absorbent polymer (SAP) beads and a hand-powered centrifuge; and a processing component, which functions as a portable lab-on-a-disc droplet digital nucleic acid amplification system, which integrates DNA extraction, nucleic acid amplification, and post-amplicon analysis in a single unit. The present invention provides a fast, cost-effective, and user-friendly solution for microbial water quality analysis in low-resource settings.

A hydrogel beads based platform for single-cell phenotypic analysis and digital molecular detection

Abstract: Microfluidic platforms integrating phenotyping and genotyping approaches have the potential to advance the understanding of single cell genotype-to-phenotype correlations. These correlations can play a key role in tackling antibiotic heteroresistance, cancer cell heterogeneity, and other related fundamental problems. Herein, we report a novel platform that enables both high-throughput digital molecular detection and single-cell phenotypic analysis, utilizing nanoliter-sized biocompatible polyethylene glycol hydrogel beads produced by a convenient and disposable centrifugal droplet generation device. The hydrogel beads have been demonstrated enhanced thermal stability, and achieved uncompromised efficiencies in digital polymerase chain reaction, digital loop-mediated isothermal amplification, and single cell phenotyping. The crosslinked hydrogel network highlights the prospective linkage of various subsequent molecular analyses to address the genotypic differences between cellular subpopulations exhibiting distinct phenotypes. Our platform shows great potential for applications in clinical practice and medical research, and promises new perspectives in mechanism elucidation of environment-evolution interaction and other basic research areas.

Electropolymerization: Studies and Applications / Electrodes and Double Layers

Abstract: Electropolymerization plays a critical role in the electrochemical systems. In this chapter, we address such role within the context of interplay between kinetics and energetics. The trains of chin radical reactions leads to the formation of thin films in electrochemical devices. The structure of so-called solid electrolyte interphase (SEI) during the initial charge/discharge cycles of the device of any kind (i.e. rechargeable battery) on the surface of electrode directly controls the the ultimate stability and longevity. In this chapter, we study the morphological evolution of SEI, both in terms of transport and thermodynamics within quantitative and qualitative contexts.