The Burden of Avian Influenza Viruses in Community Ponds in California

Emerging influenza viruses continue to challenge public health. The problem is public health science professionals have been battling emerging human influenza diseases with tactile and reactionary methods because there is a lack of knowledge and data at the human-animal interface. This research was a baseline study of the proportion of influenza A virus (IAV) in urban and rural communities in California. The population was artificial recirculating water ponds in the geographic locations of rural and urban Californian communities. Surface water samples [N = 182] were collected from artificial recirculating ponds in California. Positivity for IAV was verified by real time RT-PCR, MDCK cells for virus infectivity, nucleotide sequencing of the RNA genome, and phylogenic analysis of IAV H5N1 strains. The proportion of IAV in rural and urban ponds favored the greater burden of IAV in urban ponds over rural ponds. The presence of waterfowl and IAV M gene sequence positivity were found not to be significantly related. The geochemical properties--pH, salinity, and water temperature at time of collection--were not predictors of IAV infectivity. This baseline research study validated these water ponds as resource sites for IAV surveillance and monitoring. The social change implications of this study can be recognized at the national and international levels, to the population level, and to the individual level by providing geospatial analysis and spatial-temporal data for IAV surveillance, initiating biosecurity measures to protect poultry industries in the United States and Brazil, and contributing to the current IAV strain library. Contributions to the IAV strain library may be used to develop vaccines against human pandemics

Evaluating the suitability of RAS culture environment for rainbow trout and Atlantic salmon: A ten-year progression of applied research and technological advancements to optimize water quality and fish performance

Over the last several decades, recirculating aquaculture systems (RAS) have become a viable technology for the production of high-value food-fish. In Norway, for example, many Atlantic salmon smolt farms are now using RAS, and there is increased interest and investment in landbased facilities for the production of larger smolts, post-smolts, and, in some cases, market-size Atlantic salmon. Similar trends are taking shape in other countries, including the United States where multi-million-dollar land-based salmon and trout facilities are being planned and constructed with several already in operation. RAS continuously recycle water through specialized unit processes that recondition the flow to support intensive fish production. Core advantages of RAS include substantial water savings, diminished waste discharge, and increased flexibility for siting facilities near major seafood markets; however, a critical tradeoff is the accumulation of dissolved nutrients, metals, and compounds that can negatively affect fish health and performance in the absence of proper water treatment and system management techniques. Therefore, research that prioritizes assessment of technologies and operational metrics that optimize the RAS environment has been and will continue to be essential for sustainable industry growth. During my 21-year career as a researcher at The Conservation Fund’s Freshwater Institute, I have focused largely on evaluating the suitability of environmental conditions for salmonid production in RAS. Early research sought to identify accumulating water quality variables of concern, followed by studies designed to establish safe water quality thresholds for salmonids, namely nitrate. Assessment of specialized technologies for water quality control was intertwined with these objectives and is now at the forefront of today’s research. As the use of RAS for intensive salmonid production is still a relatively new frontier, novel questions continue to arise and evolve with increasing RAS scale, adoption of new technologies, and the declining availability of clean water resources. My thesis will track the evolution of research that I have contributed to as author and researcher within the focal area of RAS culture environment with special attention to seven peer-reviewed articles. Each manuscript resulted in novel information regarding the RAS environment for salmonids while raising new questions and providing direction for important follow-up studies. This manuscript provides a history of related research, concluding with up-to-date studies that blend optimization of the RAS culture environment with use of advanced water treatment technologies such as ozone and membrane biological reactor systems. My research synopsis will also focus on the relevance and practicality of these studies to the salmonid aquaculture industry, particularly in the United States, and seeks to extract additional value when considering the results with broader perspective related to water use and technology selection for commercial scale operations

Optimalisering av biogassproduksjon fra lignocellulose og organisk avfall: effekt av dampeksplosjon, samråtning og resirkulering av prosessvann.

Biogas production is a sustainable bioenergy process very much in demand nowadays for all the benefits it entails. It does not only allow production of clean energy and thus autonomy from fossil fuels, but also the recirculation of nutrients back to the crop fields and the decrease on greenhouse gas emissions from the agricultural sector. Biogas production is very versatile, because a wide variety of materials can be used as resources to generate methane, including organic wastes that do not present a threat to food production. With the increase interest in employing different types of available agricultural and industrial materials as biogas feedstocks, improvements along the whole process need to be addressed so to make this technology an efficient one. This thesis deals with many aspects of the anaerobic digestion process in which improvement of both process efficiency and stability can be achieved. Focus in particular was made on studying the effects of pre-treating highly lignocellulosic biomass by steam explosion on its biogas production (Paper I), mixing of different types of materials (Papers I-II-III), performing recirculation (Papers II-III) and recovery of nutrients from the digestate (Paper III). Steam explosion was tested on a hardwood crop rich in lignin, Salix viminalis, and was found to increase the methane production by up to 50 % compared to just mill Salix chips (Paper I). Different carbon-to-nitrogen (C/N) ratios were studied by screening mixtures of Salix and cattle manure with varying contents of volatile solids (VS %), which indicated that mixtures containing up to 40 % VS of steam exploded Salix could be used together with manure in anaerobic digestion and give good methane yields (Paper I). However, when substrates with high fiber content are digested in semi-continuous systems, much of the methane potential remains unexploited if the retention times are not enough for the slowly degrading materials. Ways to take advantage of such residual potential include; i) using gas tight post-storage tanks; ii) arranging post digestion systems at the biogas plants, iii) applying pretreatment to substrates that are difficult to easily digest and/or iv) applying longer hydraulic retention times. This last one can also be achieved by performing recirculation of the digestate back to the digester, thereby allowing a longer hydraulic (and solid) retention time without reducing the capacity of the system. In this study, recirculation of the liquid fraction of the digestate was evaluated as a method to enhance process efficiency and stability (Paper II). The results showed that using recirculated digestate instead of water to dilute the feedstock increased the methane production by up to 27 %. Ammonia and volatile fatty acids did not cause any inhibition problems, but accumulation of solids was more noticeable in the recirculating reactors, causing the degree of digestion to decrease after three hydraulic retention times. This indicates that optimization of the solids separation when recirculating is essential to guarantee long-term stability of systems. An enhancement of such separation was included in Paper III. Besides cattle manure and Salix, another organic waste of importance in Norway was tested, namely, “category 2” fish byproduct (Paper III). Fish farming is an extensive industrial activity in Norway, and the wastes from that sector have a high protein and fat content which translates in high energetic value. Seizing such products that benefits for Norway. When fish byproduct category 2 was mixed with steam exploded Salix and manure in continuously stirred tank reactors, yields in average increased 35 % (Paper III). Recirculation was also tested together with the addition of such nitrogen-rich substrate in order to evaluate the stability of the process with regard to levels of ammonium. The results revealed that the stability of the reactors was substantial since ammoniacal nitrogen (NH4+-N) concentrations increased to levels that otherwise would have inhibited the methanogenic process (Paper III). Recirculating digestate not only helps in recover residual methane potential, but also may favor the stability, enriching the microbial biomass that becomes tolerant to levels of NH4+-N usually corresponding to toxic levels of free ammonia. A proper co-digestion fraction of lignocelluloses together with NH4+-N rich biomass was crucial for balancing the nutrients and keeping the process running. During anaerobic digestion, nitrogen and phosphorous are mineralized and converted into plant-available nutrients. NH4+-N and phosphate could be recovered from the raw digestate and fixed into more solid fractions that can improve the final biofertilizer. The simple cost effective techniques tested in this study were struvite precipitation and bentonite adsorption, and both gave interesting results regarding the amount of NH4+-N removed (approx. 90 % and 80 % removal respectively). Even though the phosphate content was not high in the digestates, some removal was achieved mostly as struvite. Therefore, by taking into account: i) a good pre-treatment, ii) an optimum mixing ratio of different available materials, iii) savings on resources while profiting residual energy potential and enhancing stability, iv) and recovery of nutrients in the form of a richer biofertilizer, biogas can become attractive in Norway, not only as a substitute for fossil fuels in transport, but also as a source of good quality organic fertilizer, all this while also helping in some cases, in the reuse and treatment of potentially polluting organic wastes.Biogassproduksjon kan være en bærekraftig energiprosess som er mye etterspurt i dag på grunnlag av de fordeler dette innebærer for klimanøytral energi og gjenbruk av organiske avfallsprodukter til gjødsel. Det betyr ikke bare produksjon av energi som kan erstatte bruk av fossilt brennstoff, men som også kan gi grunnlag for resirkulering av næringsstoffer tilbake til dyrket mark og redusert klimagassutslipp fra landbruket. Dette er en svært allsidig prosess, siden mange forskjellige typer materialer og stoffer kan brukes som ressurs til å generere metan, som organiske avfall som ikke vil konkurrere med matproduksjon. Siden det er stor interesse for også å ta i bruk nye typer tilgjengelige landbruks- og industri avfall som råstoff for biogassproduksjon, er det nødvendig å undersøke mulige forbedringer langs hele prosessen for å gjøre teknologien mer effektiv. Denne avhandlingen peker på mange aspekter av biogassprosessen der det kan oppnås forbedring av både prosess-effektivitet og -stabilitet. Det ble spesielt satt fokus på å studere effekten av dampeksplosjon som forbehandling av biomasse med mye lignocellulose, altså fra trevirke på biogassproduksjon (Artikkel I), blanding av forskjellige typer av materialer sammen med trevirke (Artikkel I-II-III), resirkulering av prosessvann (Artikkel II-III) og gjenvinning av næringsstoffer fra råtnerest (Artikkel III). Tema for arbeidet omhandler ulike metoder for å forbedre eller optimalisere anaerob nedbrytning av lignocellulose og organisk avfall, slik at det oppnås maksimal biogassproduksjon. Dette gjøres ved dampeksplosjon, samråtning og resirkulering av prosessvann. Det betyr ikke bare hvordan produksjon av ren energi kan økes, men avhandlingen inneholder også studier av hvordan oppløste næringsstoffer i våte råtnerester kan renses og fanges og derved resirkuleres tilbake til dyrket mark. For organisk avfall, landbruk og matavfall vil dette også føre til redusert klimagassutslipp dersom mineralgjødsel erstattes. Dampeksplosjon ble testet på et lignin rikt løvtre, Salix viminalis (korgpil), som ga en økning av metanproduksjonen på opptil 50 % sammenlignet med chips (Artikkel I). Forholdstallene mellom karbon og nitrogen (C/N) som ble funnet etter screening av ulike blandinger av Salix og storfe gjødsel, indikerte at blandinger som inneholdt opp til 40 % VS (volatile solids) av dampeksplodert Salix ga godt metanutbytte (Artikkel I). Men når substrater med høyt fiberinnhold blir utråtnet i semi-kontinuerlige systemer, forblir mye av metan potensialet uutnyttet dersom oppholdstiden er for kort. For å kunne dra nytte av et slik gjenværende metan potensial innebærer, i) gasstette tanker for etterlagring, ii) etablere et ekstra utråtningstrinn ved anlegget, iii) gjennomføre en ekstra forbehandling/etterbehandling av råtneresten før ii) og/eller iv) bruke lengre oppholdstid. Dette siste kan også oppnås ved å tynne ut råstoff ved resirkulering av våt råtnerest, altså vannfasen fra avvannet slam fra bioreaktor (prosessvann) i stedet for bruk av rent vann. Dette ble undersøkt for å se om en oppnår lengre oppholdstid uten å redusere kapasiteten. I denne studien ble resirkulering av væskefraksjonen av råtneresten vurdert som en metode for å forbedre effektiviteten og mer stabil metan produksjon (Artikkel II). Resultatene viste at fortynning av råmaterialet ved hjelp av resirkulert råtnerest i stedet for med vann økte metan produksjonen med opptil 27 %. Konsentrasjonene av ammoniakk og flyktige fettsyrer var lave og førte ikke til problemer, men tørrstoff akkumulering var merkbar i reaktorene med resirkulering, noe som førte til lavere nedbrytningsgrad etter tre hydrauliske oppholdstider. Dette indiker at seperasjonen av tørrstoff i avvanningsprosessen må optimaliseres ved bruk av denne metodenmed resirkulasjon. Separasjon av en større andel partikler ble derfor inkludert i Artikkel III. Foruten storfegjødsel og Salix, ble et annet viktig norsk organisk avfall testet: fiskeavfall som biprodukt kategori 2 (Artikkel III). Fiskeoppdrett er en stor industri i Norge og avfall fra denne virksomheten har et høyt protein- og fettinnhold som betyr et høyt energiinnhold. Bedre utnyttelse av slike produkter som ellers blir dumpet i havet, ville innebære store miljømessige og økonomiske fordeler. Når fiskeavfall som biprodukt kategori 2 ble blandet med dampeksplodert Salix og gjødsel i en kontinuerlig rørt tank reaktorer, økte avkastning i gjennomsnitt 35 % (Artikkel III). Fiskeavfall er et nitrogen rikt substrat og resirkulering av prosessvann ble også testet her for å evaluere stabiliteten av prosessen med hensyn til ammonium nivåer. Resirkulert råtnerest ga ikke bare økt metanutbytte, men favoriserte også stabilitet med en mikrobiell biomasse som var tolerant for nivåer av NH4+-N som vanligvis vil korrespondere med hemmende nivåer av ammoniakk (Artikkel III). Utråtning av et nitrogen rikt substrat sammen med en tilstrekkelig andel lignocellulose og husdyrgjødsel var avgjørende for å balansere næringsstofftilgangen og holde prosessen i gang. Nitrogen og fosfor ble mineralisert under anaerobe forhold, og omgjort til plante-tilgjengelige næringsstoffer. De ble derfor undersøkt for rensing og utvinning fra den våte råtneresten til faststoff fraksjoner ved hjelp av stuvitt utfelling og betonitt adsorpsjon og begge metoder gav interessante resultater med henholdsvis 90 og 80 % NH4+-N fjerning. Fosfat innholdet var lavt i den våte råtneresten, men noe ble fjernet, det meste som struvitt. Derfor, ved å ta hensyn til: i) en hensiktsmessig forbehandling, ii) et riktig blandingsforhold mellom forskjellige tilgjengelige råstoffer til trevirke, iii) at resirkulering kan gi høyere metanutbytte og styrker stabiliteten med et lavere ressursbehov, og iv) at gjenvinning av næringsstoffer i den våte råtneresten gir gode gjødselprodukter, kan biogassproduksjon i Norge blir attraktivt både til erstatning av fossile brensler til transport og som leverandør av næringsstoffer

Quantitative High-Throughput Screen Identifies Inhibitors of the Schistosoma mansoni Redox Cascade

Schistosomiasis is a tropical disease associated with high morbidity and mortality, currently affecting over 200 million people worldwide. Praziquantel is the only drug used to treat the disease, and with its increased use the probability of developing drug resistance has grown significantly. The Schistosoma parasites can survive for up to decades in the human host due in part to a unique set of antioxidant enzymes that continuously degrade the reactive oxygen species produced by the host's innate immune response. Two principal components of this defense system have been recently identified in S. mansoni as thioredoxin/glutathione reductase (TGR) and peroxiredoxin (Prx) and as such these enzymes present attractive new targets for anti-schistosomiasis drug development. Inhibition of TGR/Prx activity was screened in a dual-enzyme format with reducing equivalents being transferred from NADPH to glutathione via a TGR-catalyzed reaction and then to hydrogen peroxide via a Prx-catalyzed step. A fully automated quantitative high-throughput (qHTS) experiment was performed against a collection of 71,028 compounds tested as 7- to 15-point concentration series at 5 µL reaction volume in 1536-well plate format. In order to generate a robust data set and to minimize the effect of compound autofluorescence, apparent reaction rates derived from a kinetic read were utilized instead of end-point measurements. Actives identified from the screen, along with previously untested analogues, were subjected to confirmatory experiments using the screening assay and subsequently against the individual targets in secondary assays. Several novel active series were identified which inhibited TGR at a range of potencies, with IC50s ranging from micromolar to the assay response limit (∼25 nM). This is, to our knowledge, the first report of a large-scale HTS to identify lead compounds for a helminthic disease, and provides a paradigm that can be used to jump-start development of novel therapeutics for other neglected tropical diseases

Iterative focused screening with biological fingerprints identifies selective Asc-1 inhibitors distinct from traditional high throughput screening

N-methyl-d-aspartate receptors (NMDARs) mediate glutamatergic signaling that is critical to cognitive processes in the central nervous system, and NMDAR hypofunction is thought to contribute to cognitive impairment observed in both schizophrenia and Alzheimer’s disease. One approach to enhance the function of NMDAR is to increase the concentration of an NMDAR coagonist, such as glycine or d-serine, in the synaptic cleft. Inhibition of alanine–serine–cysteine transporter-1 (Asc-1), the primary transporter of d-serine, is attractive because the transporter is localized to neurons in brain regions critical to cognitive function, including the hippocampus and cortical layers III and IV, and is colocalized with d-serine and NMDARs. To identify novel Asc-1 inhibitors, two different screening approaches were performed with whole-cell amino acid uptake in heterologous cells stably expressing human Asc-1: (1) a high-throughput screen (HTS) of 3 M compounds measuring 35S l-cysteine uptake into cells attached to scintillation proximity assay beads in a 1536 well format and (2) an iterative focused screen (IFS) of a 45 000 compound diversity set using a 3H d-serine uptake assay with a liquid scintillation plate reader in a 384 well format. Critically important for both screening approaches was the implementation of counter screens to remove nonspecific inhibitors of radioactive amino acid uptake. Furthermore, a 15 000 compound expansion step incorporating both on- and off-target data into chemical and biological fingerprint-based models for selection of additional hits enabled the identification of novel Asc-1-selective chemical matter from the IFS that was not identified in the full-collection HTS

IUPAC-NIST solubility data series. 81. Hydrocarbons with water and seawater - Revised and updated. Part 8. C9 hydrocarbons with water

The mutual solubility and related liquid-liquid equilibria of C9 hydrocarbons with water are exhaustively and critically reviewed. Reports of the experimental determination of solubility in 18 chemically distinct binary systems that appeared in the primary literature prior to the end of 2002 are compiled. For 8 systems, sufficient data are available to allow critical evaluation. All data are expressed as mass percent and mole fraction, as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Date Series, a new method based on the evaluation of the all experimental data for a given homologous series of aliphatic and aromatic hydrocarbons was used

Towards an Autonomous Algal Turf Scrubber: Development of an Ecologically-Engineered Technoecosystem

The development of an autonomous and internally-controlled technoecological hybrid is explored. The technoecosystem is based on an algal turf scrubber (ATS) system that combines engineered feedback control programming with internal feedback patterns within the ecosystem. An ATS is an engineered, high-turbulent aquatic system to cultivate benthic filamentous algae for the removal of pollutants from an overlying water stream. This research focuses on designing a feedback control system to control the primary production of algae in an ATS through monitoring of the algal turf metabolism and manipulation of the turbulence regime experienced by the algae. The primary production of algae in an ATS, and thus the potential of the waste treatment process, is known to be directly related to the level of turbulence in the flowing water stream resulting from the amplitude and frequency of the wave surge. Experiments are performed to understand the influence of turbulence on the biomass production rate of algae in an ATS. These results show that biomass production is correlated with wave surge amplitude at a constant frequency. Further, the influence of turbulence on the net ecosystem metabolism of an algal turf in an ATS was investigated. Results showed that both net primary production and respiration, measured through the diurnal change of inorganic carbon, follow a subsidy-stress relationship with increasing wave surge frequency, although some of this trend may be explained by the transfer of metabolic gases across the air-water interface. A feedback control algorithm, developed to monitor the net primary production and manipulate a controlling parameter, was found to converge quickly on the state of maximum primary production when the variance of the input data was low, but the convergence rate was slow at only moderate levels of input variance. The elements were assembled into a physical system in which the feedback control algorithm manipulated the turbulence of the flow in an ATS system in response to measured shifts in ecosystem metabolism. Results from this testing show that the system can converge on the maximum algal productivity at the lowest level of turbulence--the most efficient state from an engineering perspective--but in practice the system was often confounded by measurement noise. Investigation into the species composition of the dominant algae showed shifting relative abundance for those units under automated control, suggesting that certain species are more suited for utilizing the technological feedback pathways for manipulating the energy signature of their environment