93 results on '"Wade AJ"'
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2. Transit times – the link between hydrology and water quality at the catchment scale
- Author
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Hrachowitz, M., Benettin, P, van Breukelen, B.M., Fovet, O, Howden, Nicholas J.K., Ruiz, L, van der Velde, Y, and Wade, AJ
- Abstract
In spite of trying to understand processes in the same spatial domain, the catchmenthydrology and water quality scientific communities are relatively disconnectedand so are their respective models. This is emphasized by an inadequaterepresentation of transport processes, in both catchment-scale hydrological andwater quality models. While many hydrological models at the catchment scaleonly account for pressure propagation and not for mass transfer, catchment scalewater quality models are typically limited by overly simplistic representations offlow processes. With the objective of raising awareness for this issue and outliningpotential ways forward we provide a nontechnical overview of (1) the importanceof hydrology-controlled transport through catchment systems as the linkbetween hydrology and water quality; (2) the limitations of current generationcatchment-scale hydrological and water quality models; (3) the concept of transittimes as tools to quantify transport; and (4) the benefits of transit time basedformulations of solute transport for catchment-scale hydrological and water qualitymodels. There is emerging evidence that an explicit formulation of transportprocesses, based on the concept of transit times has the potential to improvethe understanding of the integrated system dynamics of catchments and to providea stronger link between catchment-scale hydrological and water qualitymodels.
- Published
- 2016
3. Obituaries.
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McFarlane JA, Fletcher J, Penney C, and Wade AJ
- Published
- 2007
4. Cryosphere and land cover influence on stream water quality in Central Asia's glacierized catchments.
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Wade AJ, Yapiyev V, Shahgedanova M, Saidaliyeva Z, Madibekov A, Kapitsa V, Kasatkin N, Ismukhanova L, Kulbekova R, Sultanbekova B, Severskiy I, Esenaman M, Kalashnikova O, Usubaliev R, Akbarov F, Umirzakov G, Petrov M, Rakhimov I, Kayumova D, and Kayumov A
- Abstract
This work helps address recent calls for systematic water quality assessment in Central Asia and considers how nutrient and salinity sources, and transport, affect water quality along the continuum from the cryosphere to the lowland plains. Spatial and, for the first time, temporal variations in stream water pH, temperature, electrical conductivity, and nitrate and phosphate concentrations are presented for four catchments (485-13,500 km
2 ), all with glaciers and major urban areas. The catchments studied were: Kaskelen (Kazakhstan), Ala-Archa (Kyrgyzstan), Chirchik (Uzbekistan) and the Kofarnihon (Tajikistan). Measurements were made in cryosphere, stream water, groundwater, reservoir and lake samples over a 22-month period at fortnightly intervals from 35 sites. The results highlight that glacier, permafrost and rock glacier outflows were primary and secondary nitrate sources (>1 mg N L-1 ) to the headwaters, and there were major increases in salinity and nitrate concentrations where rivers receive inputs from agriculture and settlements. Overall, the water quality complied with national and World Health Organization standards, however there were pollution hot-spots with shallow urban groundwaters contaminated with nitrate (>11 mg N L-1 ) and stream electrical conductivity above 800 μS cm-1 in some agricultural areas indicative of high salinity. Phosphate concentrations were generally low (<0.06 mg P L-1 ) throughout the catchments, though elevated (>0.2 mg P L-1 ) in urban areas due to effluent contamination. A melt water dilution effect along the main river channels was discernible, in the electrical conductivity and nitrate concentration seasonal dynamics, 100 s of km from the headwaters. Thus, the input of relatively clean water from the cryosphere is an important regulator of main channel water quality in the urban and farmed lowland plains adjacent to the Tien Shan and Pamir. Improved sewage treatment is needed in urban areas., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Andrew J Wade reports financial support and article publishing charges were provided by UK Research and Innovation. Maria Shahgedanova reports financial support and article publishing charges were provided by UK Research and Innovation. Andrew J Wade reports a relationship with UK Research and Innovation that includes: funding grants. Maria Shahgedanova reports a relationship with UK Research and Innovation that includes: funding grants. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)- Published
- 2024
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5. Negative and positive mental health characteristics of affected family members: Findings from a cross-sectional Australian general population gambling study.
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Spence K, Merkouris SS, Jackson AC, Wade AJ, and Dowling NA
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- Humans, Male, Female, Middle Aged, Cross-Sectional Studies, Adult, Quality of Life psychology, Tasmania epidemiology, Adaptation, Psychological, Australia epidemiology, Mental Health, Gambling psychology, Gambling epidemiology, Family psychology
- Abstract
Despite the impact of problem gambling on affected family members (AFMs), there are limited large-scale population level studies identifying the negative mental health (NMH) and positive mental health (PMH) characteristics of AFMs. Furthermore, no study has explored whether PMH characteristics are protective in the relationships between AFM status and NMH characteristics. This study involved secondary data analysis from the Third Social and Economic Impact Study of Gambling in Tasmania. Using a subsample of 1,869 adults (48.30 % male; mean
age = 48.48; 4.67 % AFMs), this study aimed to explore whether: (1) AFM status is associated with NMH (depression, anxiety, panic, post-traumatic stress disorder, social anxiety, binge drinking, tobacco use, and drug use symptoms) and PMH (quality of life [QOL], personal growth/autonomy, interpersonal/social skills, coping skills) characteristics after separately controlling for sociodemographic, problem gambling severity, and other NMH characteristics; (2) PMH characteristics moderate (buffer) the relationships between AFM status and NMH characteristics; and (3) gender influences these relationships. AFM status, defined as exposure to family member gambling problems, significantly positively predicted NMH characteristics (depression, anxiety, panic, PTSD, and tobacco use symptoms) and negatively predicted QOL (physical, social) and planning coping. The strength of these relationships generally attenuated after controlling for various covariates. Gender did not moderate these relationships. Religious coping exacerbated the relationship between AFM status and panic disorder symptoms. These findings can inform the development of intervention initiatives for family members exposed to gambling problems. Future population-representative research is required using a range of affected other types, longitudinal study designs, and more comprehensive measures., Competing Interests: Declaration of competing interest 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., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)- Published
- 2024
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6. Transferability of a Bayesian Belief Network across diverse agricultural catchments using high-frequency hydrochemistry and land management data.
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Negri C, Schurch N, Wade AJ, Mellander PE, Stutter M, Bowes MJ, Mzyece CC, and Glendell M
- Abstract
Biogeochemical catchment models are often developed for a single catchment and, as a result, often generalize poorly beyond this. Evaluating their transferability is an important step in improving their predictive power and application range. We assess the transferability of a recently developed Bayesian Belief Network (BBN) that simulated monthly stream phosphorus (P) concentrations in a poorly-drained grassland catchment through application to three further catchments with different hydrological regimes and agricultural land uses. In all catchments, flow and turbidity were measured sub-hourly from 2009 to 2016 and supplemented with 400-500 soil P test measurements. In addition to a previously parameterized BBN, five further model structures were implemented to incorporate in a stepwise way: in-stream P removal using expert elicitation, additional groundwater P stores and delivery, and the presence or absence of septic tank treatment, and, in one case, Sewage Treatment Works. Model performance was tested through comparison of predicted and observed total reactive P (TRP) concentrations and percentage bias (PBIAS). The original BBN accurately simulated the absolute values of observed flow and TRP concentrations in the poorly and moderately drained catchments (albeit with poor apparent percentage bias scores; 76 % ≤ PBIAS≤94 %) irrespective of the dominant land use, but performed less well in the groundwater-dominated catchments. However, including groundwater total dissolved P (TDP) and Sewage Treatment Works (STWs) inputs, and in-stream P uptake improved model performance (-5 % ≤ PBIAS≤18 %). A sensitivity analysis identified redundant variables further helping to streamline the model applications. An enhanced BBN model capable for wider application and generalisation resulted., Competing Interests: Declaration of competing interest 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., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)
- Published
- 2024
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7. Missed Opportunities: A Retrospective Study of Hepatitis C Testing in Hospital Inpatients.
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Roder C, Cosgrave C, Mackie K, McNamara B, Doyle JS, and Wade AJ
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- Humans, Retrospective Studies, Male, Female, Middle Aged, Adult, Substance Abuse, Intravenous complications, Substance Abuse, Intravenous epidemiology, Hospitalization statistics & numerical data, Victoria epidemiology, Aged, Emergency Service, Hospital statistics & numerical data, Mass Screening methods, Young Adult, Hepatitis C epidemiology, Hepatitis C diagnosis, Inpatients statistics & numerical data, Hepacivirus isolation & purification
- Abstract
Increasing testing is key to achieving hepatitis C elimination. This retrospective study aimed to assess the testing cascade of patients at a regional hospital in Victoria, Australia, who inject drugs or are living with hepatitis C, to identify missed opportunities for hepatitis C care. Adult hospital inpatients and emergency department (ED) attendees from 2018 to 2021 with indications for intravenous drug use (IDU) or hepatitis C on their discharge or ED summary were included. Data sources: hospital admissions, pathology, hospital pharmacy, and outpatients. We assessed progression through the testing cascade and performed logistic regression analysis for predictors of hepatitis C care, including testing and treatment. Of 79,923 adults admitted, 1345 (1.7%) had IDU-coded separations and 628 (0.8%) had hepatitis C-coded separations (N = 1892). Hepatitis C virus (HCV) status at the end of the study was unknown for 1569 (82.9%). ED admissions were associated with increased odds of not providing hepatitis C care (odds ratio 3.29, 95% confidence interval 2.42-4.48). More than 2% of inpatients at our hospital have an indication for testing, however, most are not being tested despite their hospital contact. As we work toward HCV elimination in our region, we need to incorporate testing and linkage strategies within hospital departments with a higher prevalence of people at risk of infection.
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- 2024
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8. Outreach nurses critical for delivery of HIV care to women in western Victoria.
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Gador-Whyte AP, Roder C, Hamilton R, Fay H, Huning E, Nicholson E, Mackie K, Athan E, and Wade AJ
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- Humans, Female, HIV Infections drug therapy, Anti-HIV Agents therapeutic use
- Abstract
Women living with HIV in regional Victoria face barriers accessing care. We evaluated the care cascade and outreach nurse support required for women attending our service between 2005 and 2020. A total of 33 women attended; 97% (32/33) were on antiretroviral therapy; 67% (22/33) retained in care, 27% (9/33) transferred and 6% (2/33) lost to follow up. Of women retained in care, 95% (21/22) were on antiretroviral therapy and 91% (20/22) had virological suppression. A total of 91% (30/33) required outreach nurse care (median care episodes 100/woman; IQR 44-179) - most frequently (87%; 26/30) liaising with pharmacies and prescribers. Outreach nurses are critical in achieving UNAIDS targets for women in western Victoria.
- Published
- 2023
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9. Trait Loss in Evolution: What Cavefish Have Taught Us about Mechanisms Underlying Eye Regression.
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Sifuentes-Romero I, Aviles AM, Carter JL, Chan-Pong A, Clarke A, Crotty P, Engstrom D, Meka P, Perez A, Perez R, Phelan C, Sharrard T, Smirnova MI, Wade AJ, and Kowalko JE
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- Animals, Eye, Pigmentation genetics, Caves, Biological Evolution, Characidae genetics
- Abstract
Reduction or complete loss of traits is a common occurrence throughout evolutionary history. In spite of this, numerous questions remain about why and how trait loss has occurred. Cave animals are an excellent system in which these questions can be answered, as multiple traits, including eyes and pigmentation, have been repeatedly reduced or lost across populations of cave species. This review focuses on how the blind Mexican cavefish, Astyanax mexicanus, has been used as a model system for examining the developmental, genetic, and evolutionary mechanisms that underlie eye regression in cave animals. We focus on multiple aspects of how eye regression evolved in A. mexicanus, including the developmental and genetic pathways that contribute to eye regression, the effects of the evolution of eye regression on other traits that have also evolved in A. mexicanus, and the evolutionary forces contributing to eye regression. We also discuss what is known about the repeated evolution of eye regression, both across populations of A. mexicanus cavefish and across cave animals more generally. Finally, we offer perspectives on how cavefish can be used in the future to further elucidate mechanisms underlying trait loss using tools and resources that have recently become available., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology.)
- Published
- 2023
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10. Leave No-One Behind: A Retrospective Study of Hepatitis C Testing and Linkage to Care for Hospital Inpatients.
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Roder C, Cosgrave C, Mackie K, Roberts SK, Hellard ME, Wade AJ, and Doyle JS
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- Adult, Humans, Retrospective Studies, Antiviral Agents therapeutic use, Inpatients, Hepacivirus genetics, RNA, Hospitals, Substance Abuse, Intravenous, Hepatitis C diagnosis, Hepatitis C drug therapy, Hepatitis C epidemiology, Hepatitis C, Chronic diagnosis, Hepatitis C, Chronic drug therapy, Hepatitis C, Chronic epidemiology
- Abstract
Hospital admissions are a missed opportunity to engage people living with hepatitis C virus (HCV) into care. This study aimed to describe the proportion of hospital inpatients and emergency department (ED) patients identified with hepatitis C who were subsequently linked to care and treatment at a metropolitan health service in Melbourne, Australia. Data were collected retrospectively from hospital databases (admissions, notifiable diseases, and pharmacy) for all adults admitted or attending the ED with separation coding indicating hepatitis C infection from March 2016 to March 2019. There were 2149 patients with at least one separation with hepatitis C coding. 15.4% (331/2149) had a documented antibody test, 4.6% (99/2149) had a documented RNA test, and 8.3% (179/2149) had a DAA prescription dispensed by hospital pharmacy. Antibody positivity was 95.2% (315/331) and RNA (when completed) was detected in 37.4% (37/99). Hepatitis specialist units had the highest rate of hepatitis C coded separations and RNA testing (39/88; 44.3%), mental health had the highest rate of antibody testing (70/276; 25.4%). Emergency had the lowest rate of antibody testing (101/1075; 13.7%) and the third highest rate of RNA testing (32/94; 34.1%), but the highest rate of RNA detected (15/32; 46.9%). This study highlights key steps to improve the care cascade. Simplified diagnostic pathways, expansion of hepatitis C care services, and clear in-hospital pathways to link patients to care would be beneficial in this setting. To scale up hepatitis C testing and treatment as part of national elimination strategies, hospital systems need to target interventions to their local data.
- Published
- 2023
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11. Interventions to eliminate hepatitis C: which ones suit your community?
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Wade AJ and Doyle JS
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- Hepacivirus, Humans, Hepatitis C drug therapy, Hepatitis C epidemiology, Hepatitis C prevention & control
- Abstract
Competing Interests: AJW has previously received funding for investigator-initiated research from AbbVie. JSD has received funding for investigator-initiated research and honoraria from AbbVie and Gilead Sciences.
- Published
- 2022
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12. Area-level social and economic factors and the local incidence of SARS-CoV-2 infections in Victoria during 2020.
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Roder C, Maggs C, McNamara BJ, O'Brien D, Wade AJ, Bennett C, Pasco JA, and Athan E
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- Australia, Economic Factors, Humans, Incidence, SARS-CoV-2, COVID-19 epidemiology
- Abstract
Objective: To examine associations between area-level socio-economic factors and the incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in Victoria during 2020., Design, Setting: Population-level ecological study of the incidence of SARS-CoV-2 infections in Victoria, by postcode, 1 March - 13 August 2020., Main Outcome Measures: Relationships between the incidence of SARS-CoV-2 infections by postcode (Department of Health and Human Services data published on The Age website), and demographic, education level, ethnic background, economic and employment-related factors, housing-related factors, and social disadvantage (Australian Bureau of Statistics data for 2014-19), expressed as incidence rate ratios (IRRs)., Results: During the study period, 15 482 SARS-CoV-2 infections with associated postcodes were recorded in Victoria. Incidence was higher for metropolitan than regional postcodes (418.3 v 62 infections per 100 000 population; IRR, 6.2; 95% CI, 4.6-8.2). In regional postcodes, incidence rose with mean household size (per person: IRR, 7.30; 95% CI, 4.37-12.2), unemployment proportion (per percentage point: IRR, 1.50; 95% CI, 1.33-1.69), and proportions for whom rent (IRR, 1.15; 95% CI, 1.07-1.22) or mortgage repayments (IRR, 1.22; 95% CI, 1.15-1.28) exceeded 30% of household income. In metropolitan areas, incidence increased with unemployment proportion (IRR, 1.14; 95% CI, 1.05-1.23) and proportion without paid leave (IRR, 1.22; 95% CI, 1.02-1.45). Incidence also increased with proportion speaking languages other than English at home (regional: IRR, 1.08; 95% CI, 1.06-1.11; metropolitan: IRR, 1.01; 95% CI, 1.002-1.02) and with Indigenous Australian proportion (metropolitan only: IRR, 1.91; 95% CI, 1.10-2.73)., Conclusions: Socio-economic factors may have contributed to the non-homogeneous incidence of SARS-CoV-2 infections across Victoria during 2020., (© 2022 AMPCo Pty Ltd.)
- Published
- 2022
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13. A multi-site, nurse-coordinated hepatitis C model of care in primary care and community services in Melbourne, Australia.
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Harney BL, Whitton B, Paige E, Brereton R, Weiss R, Membrey D, Wade AJ, Iser D, Kemp W, Roberts SK, Spelman T, Sacks-Davis R, Hellard ME, and Doyle JS
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- Antiviral Agents therapeutic use, Australia, Hepacivirus genetics, Humans, Primary Health Care, Social Welfare, Hepatitis C complications, Hepatitis C diagnosis, Hepatitis C drug therapy, Hepatitis C, Chronic complications, Hepatitis C, Chronic diagnosis, Hepatitis C, Chronic drug therapy, Substance Abuse, Intravenous complications
- Abstract
Background: Hepatitis C virus (HCV) treatment through primary care and community-based services will be a critical component of HCV elimination. We evaluated a nurse-coordinated programme providing care across eight sites and analysed progression through the HCV care cascade., Methods: People-accessing services from six primary care clinics, a homeless crisis accommodation provider and a mental health service were directly referred to nurses or engaged by nurses during regular clinic visits. Nurses supported HCV testing, treatment and follow-up. The prescription was provided by affiliated clinicians. Logistic regression was used to examine factors associated with treatment commencement and sustained virological response (SVR) testing., Results: Of 640 people referred to and/or engaged by the nurses from January 2017 to July 2019, 518 had an HCV RNA test of whom 381 (74%) were HCV RNA positive. Treatment was commenced by 281 (74%) people of whom 161 had an SVR test, 157 (97.5%) were cured. Opioid agonist therapy was associated with treatment commencement (aOR 2.68, 95% CI 1.48-4.88). People who were homeless/unstably housed were less likely to commence treatment (aOR 0.45, 95% CI 0.23-0.87). Treatment prescription from a specialist (aOR 2.39, 95% CI 1.20-4.74) and recent injection drug use (<6 months) (aOR 2.15, 95% CI 1.07-4.31) was associated with SVR testing., Conclusion: A nurse-coordinated model of care led to high levels of HCV treatment uptake and cure amongst people attending primary care and community services. More tailored models of care may be beneficial for people who are homeless or have unstable housing. These results support primary care and community-based hepatitis C treatment., (© 2022 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)
- Published
- 2022
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14. Psychiatrists can treat hepatitis C.
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Roder C, Nguyen P, Harvey C, Wardrop M, Finlay J, Ogunleye L, Hill H, Athan E, and Wade AJ
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- Hepacivirus, Humans, Hepatitis C drug therapy, Psychiatry
- Published
- 2021
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15. Efficacy and Safety of Sofosbuvir/Velpatasvir/Voxilaprevir for Hepatitis C Virus (HCV) NS5A-Inhibitor Experienced Patients With Difficult to Cure Characteristics.
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Papaluca T, Roberts SK, Strasser SI, Stuart KA, Farrell G, MacQuillan G, Dore GJ, Wade AJ, George J, Hazeldine S, O'Beirne J, Wigg A, Fisher L, McGarity B, Sawhney R, Sinclair M, Thomas J, Valiozis I, Weltman M, Wilson M, Woodward A, Ahlenstiel G, Haque M, Levy M, Prewett E, Sievert W, Sood S, Tse E, Valaydon Z, Bowden S, Douglas M, New K, O'Keefe J, Hellard M, Doyle J, Stoove M, and Thompson AJ
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- Aminoisobutyric Acids, Antiviral Agents adverse effects, Carbamates, Cyclopropanes, Genotype, Hepacivirus genetics, Heterocyclic Compounds, 4 or More Rings, Humans, Lactams, Macrocyclic, Leucine analogs & derivatives, Male, Middle Aged, Proline analogs & derivatives, Quinoxalines, Sofosbuvir adverse effects, Sulfonamides, Sustained Virologic Response, Treatment Outcome, Hepatitis C drug therapy, Hepatitis C, Chronic complications, Hepatitis C, Chronic drug therapy
- Abstract
Background: In clinical trials, hepatitis C virus (HCV) salvage treatment with sofosbuvir/velpatasvir/voxilaprevir (SOF/VEL/VOX) achieved an SVR12 rate of >95% in NS5A-experienced participants. Lower SVR12 rates have been reported in real-world studies, particularly for genotype (GT)3 infection and cirrhosis. We determined the efficacy and safety of SOF/VEL/VOX in a large real-world cohort., Methods: We assessed the efficacy of salvage SOF/VEL/VOX for HCV infection in NS5A-inhibitor experienced participants with cirrhosis and portal hypertension, prior liver transplantation (LT) or severe extra-hepatic manifestations. SOF/VEL/VOX was available via an early access program. The primary outcome was SVR12. Secondary outcome was frequency of adverse events (AE)., Findings: Ninety-seven participants were included. Median age was 58, 82% were male, 78% had cirrhosis, most with portal hypertension (61%, n = 46/76), and 18% had prior-LT. Of the cirrhotic participants, 96% were Child-Turcotte-Pugh class A, and 4% were class B. Of the 72% with GT3, 76% were also cirrhotic. By intention-to-treat analysis, SVR12 rate was 85% (n = 82/97). Per protocol, the SVR12 rate was 90%, including 91% in GT1 (GT1a n = 18/18, GT1b n = 2/4), 89% in GT3 (n = 59/66) and 100% in GT6 (n = 3/3). SVR12 in participants with GT3 and cirrhosis was 90%. No predictors of non-SVR12 were identified. There were 4 serious AEs including 1 death and 3 hepatic decompensation events. NS5A resistance-associated substitutions detected at baseline did not affect SVR12., Conclusions: This real-world study confirms high efficacy of SOF/VEL/VOX for the treatment of difficult-to-cure NS5A-inhibitor experienced patients, including those with GT3 and cirrhosis. Treatment was well tolerated in most; however, serious AEs can occur in those with advanced liver disease., (© The Author(s) 2020. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)
- Published
- 2021
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16. Spatial properties affecting the sensitivity of soil water dissolved organic carbon long-term median concentrations and trends.
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Sawicka K, Clark JM, Vanguelova E, Monteith DT, and Wade AJ
- Abstract
It is increasingly clear that increases in dissolved organic carbon in upland waters in recent decades have often been dominated by acid deposition, but reasons for substantial variation in rates of change remain unclear. This paper focuses on the extent to which spatial properties, such as variation in soil properties, atmospheric deposition and climate, affect the sensitivity of DOC concentrations in soil water. The purpose is to i) examine evidence for differences in site average concentrations and trends in soil water DOC between sites with contrasting ecosystem properties, i.e. vegetation cover and soil type, and ii) identify the wider combination of site characteristics that best explain variation in these DOC metrics between sites. We collated soil water and deposition chemistry, soil chemistry and meteorological data from 15 long-term UK monitoring sites (1992-2010) covering a range of soils, vegetation, climate and acid deposition levels. Mineral soils under forests showed the greatest range of long-term mean DOC concentrations and trends. Regression analysis indicated that acid and sea-salt deposition, and soil sensitivity to acidification were the factors most strongly associated with spatial variation in mean DOC concentrations. Spatial variation in DOC trends were best explained by Al saturation and water flux. Overall, the sensitivity of DOC release from soil to changes in pollutant deposition could be related to the type of vegetation cover and soils chemistry properties, such as Al saturation, divalent base cation content and hydrological regime. The identification of the ecosystem properties that appear most influential in modifying DOC production and responses to long-term drivers, helps elucidate potential mechanistic explanations for differences in DOC dynamics across seemingly similar ecosystems, and points to the importance of DOC mobility in regulating its dynamics., Competing Interests: Declaration of competing interest 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., (Copyright © 2021. Published by Elsevier B.V.)
- Published
- 2021
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17. Pregnancy - a key moment for engaging women with hepatitis B in care.
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Roder C, Chand S, Streat S, Beynon S, Huning E, Dabkowski P, Athan E, and Wade AJ
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- Female, Hepatitis B Surface Antigens, Hepatitis B virus, Humans, Pregnancy, Hepatitis B prevention & control, Hepatitis B, Chronic
- Published
- 2021
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18. A Bayesian network to simulate macroinvertebrate responses to multiple stressors in lowland streams.
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de Vries J, Kraak MHS, Skeffington RA, Wade AJ, and Verdonschot PFM
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- Animals, Bayes Theorem, Environmental Monitoring, Invertebrates, Ecosystem, Rivers
- Abstract
Aquatic ecosystems are affected by multiple environmental stressors across spatial and temporal scales. Yet the nature of stressor interactions and stressor-response relationships is still poorly understood. This hampers the selection of appropriate restoration measures. Hence, there is a need to understand how ecosystems respond to multiple stressors and to unravel the combined effects of the individual stressors on the ecological status of waterbodies. Models may be used to relate responses of ecosystems to environmental changes as well as to restoration measures and thus provide valuable tools for water management. Therefore, we aimed to develop and test a Bayesian Network (BN) for simulating the responses of stream macroinvertebrates to multiple stressors. Although the predictive performance may be further improved, the developed model was shown to be suitable for scenario analyses. For the selected lowland streams, an increase in macroinvertebrate-based ecological quality (EQR) was predicted for scenarios where the streams were relieved from single and multiple stressors. Especially a combination of measures increasing flow velocity and enhancing the cover of coarse particulate organic matter showed a significant increase in EQR compared to current conditions. The use of BNs was shown to be a promising avenue for scenario analyses in stream restoration management. BNs have the capacity for clear visual communication of model dependencies and the uncertainty associated with input data and results and allow the combination of multiple types of knowledge about stressor-effect relations. Still, to make predictions more robust, a deeper understanding of stressor interactions is required to parametrize model relations. Also, sufficient training data should be available for the water type of interest. Yet, the application of BNs may now already help to unravel the contribution of individual stressors to the combined effect on the ecological quality of water bodies, which in turn may aid the selection of appropriate restoration measures that lead to the desired improvements in macroinvertebrate-based ecological quality., Competing Interests: Declaration of Competing Interest 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., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2021
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19. In support of community-based hepatitis C treatment with triage of people at risk of cirrhosis to specialist care.
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Wade AJ, Doyle JS, Draper B, Howell J, Iser D, Roberts SK, Kemp W, Thompson AJ, and Hellard ME
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- Health Services Accessibility, Humans, Liver Cirrhosis epidemiology, Triage, Hepatitis C diagnosis, Hepatitis C drug therapy, Hepatitis C epidemiology, Pharmaceutical Preparations
- Published
- 2021
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20. Can community pharmacists treat hepatitis C virus?
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Wade AJ
- Subjects
- Humans, Opiate Substitution Treatment, Pharmacists, Treatment Outcome, Antiviral Agents, Hepacivirus
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- 2020
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21. Indicators of potential health-related social needs and the association with perceived health and well-being outcomes among community-dwelling medicare beneficiaries.
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Engelberg Anderson JK, Jain P, Wade AJ, Morris AM, Slaboda JC, and Norman GJ
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- Aged, Aged, 80 and over, Cross-Sectional Studies, Female, Humans, Male, Nutritional Status, Personal Satisfaction, Prevalence, Social Isolation psychology, Transportation, United States, Health Status, Independent Living psychology, Medicare statistics & numerical data, Quality of Life psychology
- Abstract
Purpose: Health-related social needs (HRSNs) can make older adults' more vulnerable and impact their health, well-being, and ability to age-in-place. The current study assessed the prevalence of potential HRSNs (pHRSNs) across several domains (e.g., transportation, social isolation) and explored the associations with health and well-being outcomes in a sample of Medicare beneficiaries., Methods: Cross-sectional analyses were conducted with a representative sample of community-dwelling Medicare beneficiaries (N = 5758) from the 2012 National Health and Aging Trends Study. Binary indicators of pHRSNs were created for five domains: medical and utility financial needs (MUFN), housing, nutrition, social isolation, and transportation. Outcomes were depression/anxiety, self-rated health, meaning/satisfaction, perceived control/adaptability. Variables were weighted, and multivariate regression models assessed associations between pHRSN variables and outcomes, controlling for sociodemographics and health conditions., Results: Of the estimated 32 million community-dwelling beneficiaries, approximately 13.3 million were positive for ≥ 1 pHRSN and 11.4 million for ≥ 2 pHRSNs. The prevalence by domain was 7% for housing, 8% for transportation, 12% for UMFN and nutrition, and 33% for social isolation. Each domain, except for housing, was significantly (p < .05) associated with at least two of the four outcomes, where being positive for a pHRSN was associated with greater depression/anxiety and poorer self-rated general health., Conclusions: Over 40% of Medicare beneficiaries had ≥ 1 pHRSN indicators, which means they are more vulnerable and that may limit their ability to age-in-place. Given the growing aging population, better measures and methods are needed to identify, monitor, and address HRSNs. For example, leveraging existing community-based services through coordinated care may be an effective strategy to address older adults' HRSNs.
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- 2020
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22. Australia needs to increase testing to achieve hepatitis C elimination.
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Scott N, Sacks-Davis R, Wade AJ, Stoove M, Pedrana A, Doyle JS, Thompson AJ, Wilson DP, and Hellard ME
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Antiviral Agents therapeutic use, Australia epidemiology, Basic Reproduction Number, Child, Child, Preschool, Female, Goals, Harm Reduction, Hepatitis C drug therapy, Hepatitis C epidemiology, Humans, Incidence, Infant, Infant, Newborn, Male, Middle Aged, Models, Theoretical, Prevalence, Public Health, Substance Abuse, Intravenous, World Health Organization, Young Adult, Diagnostic Tests, Routine statistics & numerical data, Disease Eradication, Hepatitis C diagnosis
- Abstract
Objectives: To assess progress in Australia toward the 2030 WHO hepatitis C elimination targets two years after the introduction of highly effective direct-acting antiviral (DAA) treatments., Design: Analysis of quarterly data on government-subsidised hepatitis C RNA testing and hepatitis C treatment in Australia, January 2013 - June 2018. Changes in testing and treatment levels associated with DAA availability were assessed in an autoregressive integrated moving average (ARIMA) statistical model, and the impact by 2030 of different levels of testing and treatment were estimated using a mathematical model., Major Outcome Measures: Hepatitis C prevalence among people who inject drugs; annual hepatitis C incidence relative to 2015 levels; projections for the hepatitis C care cascade in 2030., Results: The mean annual number of treatments initiated for people with hepatitis C increased from 6747 during 2013-2015 (before the introduction of DAAs) to 28 022 during 2016-18; the mean annual number of diagnostic RNA tests increased from 17 385 to 23 819. If current trends in testing and treatment continue (ie, 2018 testing numbers are maintained but treatment numbers decline by 50%), it is projected that by 2030 only 72% of infected people would be treated (by 2025 all people diagnosed with hepatitis C would be treated). The incidence of hepatitis C in 2030 would be 59% lower than in 2015, well short of the WHO target of an 80% reduction. The identification and testing of people exposed to hepatitis C must be increased by at least 50% for Australia to reach the WHO elimination targets., Conclusion: Hepatitis C elimination programs in Australia should focus on increasing testing rates and linkage with care to maintain adequate levels of treatment., (© 2020 The Authors. Medical Journal of Australia published by John Wiley & Sons Australia, Ltd on behalf of AMPCo Pty Ltd.)
- Published
- 2020
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23. Data on the theoretical X-Ray attenuation and transmissions for lithium-ion battery cathodes.
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Heenan TMM, Tan C, Wade AJ, Jervis R, Brett DJL, and Shearing PR
- Abstract
This article reports the data required for planning attenuation-based X-ray characterisation e.g. X-ray computed tomography (CT), of lithium-ion (Li-ion) battery cathodes. The data reported here is to accompany a co-submitted manuscript (10.1016/j.matdes.2020.108585 [1]) which compares two well-known X-ray attenuation data sources: Henke et al. and Hubbell et al., and applies methodology reported by Reiter et al. to extend this data towards the practical characterisation of prominent cathode materials. This data may be used to extend beyond the analysis reported in the accompanying manuscript, and may aid in the applications for other materials, not limited to Li-ion batteries., (© 2020 The Author(s).)
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- 2020
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24. Outcomes of Treatment for Hepatitis C in Primary Care, Compared to Hospital-based Care: A Randomized, Controlled Trial in People Who Inject Drugs.
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Wade AJ, Doyle JS, Gane E, Stedman C, Draper B, Iser D, Roberts SK, Kemp W, Petrie D, Scott N, Higgs P, Agius PA, Roney J, Stothers L, Thompson AJ, and Hellard ME
- Subjects
- Australia, Hepacivirus, Hospitals, Humans, New Zealand epidemiology, Primary Health Care, Antiviral Agents therapeutic use, Hepatitis C drug therapy, Hepatitis C, Chronic drug therapy, Pharmaceutical Preparations, Substance Abuse, Intravenous drug therapy
- Abstract
Background: To achieve the World Health Organization hepatitis C virus (HCV) elimination targets, it is essential to increase access to direct-acting antivirals (DAAs), especially among people who inject drugs (PWID). We aimed to determine the effectiveness of providing DAAs in primary care, compared with hospital-based specialist care., Methods: We randomized PWID with HCV attending primary care sites in Australia or New Zealand to receive DAAs at their primary care site or local hospital (standard of care [SOC]). The primary outcome was to determine whether people treated in primary care had a noninferior rate of sustained virologic response at Week 12 (SVR12), compared to historical controls (consistent with DAA trials at the time of the study design); secondary outcomes included comparisons of treatment initiation, SVR12 rates, and the care cascade by study arm., Results: We recruited 140 participants and randomized 136: 70 to the primary care arm and 66 to the SOC arm. The SVR12 rate (100%, 95% confidence interval [CI] 87.7-100) of people treated in primary care was noninferior when compared to historical controls (85% assumed). An intention-to-treat analysis revealed that the proportion of participants commencing treatment in the primary care arm (75%, 43/57) was significantly higher than in the SOC arm (34%, 18/53; P < .001; relative risk [RR] 2.48, 95% CI 1.54-3.95), and the proportion of participants with SVR12 was significantly higher in the primary care arm, compared to in the SOC arm (49% [28/57] and 30% [16/53], respectively; P = .043; RR 1.63, 95% CI 1.0-2.65)., Conclusions: Providing HCV treatment in primary care increases treatment uptake and cure rates. Approaches that increase treatment uptake among PWID will accelerate elimination strategies., Clinical Trials Registration: NCT02555475., (© The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)
- Published
- 2020
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25. A cost-effectiveness analysis of primary versus hospital-based specialist care for direct acting antiviral hepatitis C treatment.
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Palmer AY, Wade AJ, Draper B, Howell J, Doyle JS, Petrie D, Thompson AJ, Wilson DP, Hellard ME, and Scott N
- Subjects
- Antiviral Agents therapeutic use, Cost-Benefit Analysis, Hospitals, Humans, Hepatitis C drug therapy, Hepatitis C, Chronic drug therapy, Substance Abuse, Intravenous drug therapy
- Abstract
Background: Hepatitis C virus elimination may be possible by scaling up direct-acting antiviral (DAA) treatment. Due to the safety and simplicity of DAA treatment, primary care-based treatment delivery is now feasible, efficacious and may be cheaper than hospital-based specialist care. In this paper, we use Prime Study data - a randomised controlled trial comparing the uptake of DAA treatment between primary and hospital-based care settings amongst people who inject drugs (PWID) - to estimate the cost of initiating treatment for PWID diagnosed with hepatitis C in primary care compared to hospital-based care., Methods: The total economic costs associated with delivering DAA treatment (post hepatitis C diagnosis) within the Prime study - including health provider time/training, medical tests, equipment, logistics and pharmacy costs - were collected. Appointment data were used to estimate the number/type of appointments required to initiate treatment in each case, or the stage at which loss to follow up occurred., Results: Among the hepatitis C patients randomised to be treated within primary care, 43/57 (75%) commenced treatment at a mean cost of A$885 (95% CI: A$850-938) per patient initiating treatment. In hospital-based care, 18/53 hepatitis C patients (34%) commenced treatment at a mean cost of A$2078 (range: A$2052-2394) per patient initiating treatment - more than twice as high as primary care. The lower cost in the primary care arm was predominantly the result of increased retention in care compared to the hospital-based arm., Conclusions: Compared to hospital-based care, providing hepatitis C services for PWID in primary care can improve treatment uptake and approximately halve the average cost of treatment initiation. To improve treatment uptake and cure, countries should consider primary care as the main model for hepatitis C treatment scale-up., (Copyright © 2019 Elsevier B.V. All rights reserved.)
- Published
- 2020
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26. Home and community-based services coordination for homebound older adults in home-based primary care.
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Norman GJ, Wade AJ, Morris AM, and Slaboda JC
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- Aged, Community Health Services trends, Female, Homebound Persons rehabilitation, House Calls trends, Humans, Male, Primary Health Care trends, Self Report, United States, Community Health Services methods, Home Care Services trends, Homebound Persons psychology, Primary Health Care methods, Surveys and Questionnaires
- Abstract
Background: Medically complex vulnerable older adults often face social challenges that affect compliance with their medical care plans, and thus require home and community-based services (HCBS). This study describes how non-medical social needs of homebound older adults are assessed and addressed within home-based primary care (HBPC) practices, and to identify barriers to coordinating HCBS for patients., Methods: An online survey of members of the American Academy of Home Care Medicine (AAHCM) was conducted between March through November 2016 in the United States. A 56-item survey was developed to assess HBPC practice characteristics and how practices identify social needs and coordinate and evaluate HCBS. Data from 101 of the 150 surveys received were included in the analyses. Forty-four percent of respondents were physicians, 24% were nurse practitioners, and 32% were administrators or other HBPC team members., Results: Nearly all practices (98%) assessed patient social needs, with 78% conducting an assessment during the intake visit, and 88% providing ongoing periodic assessments. Seventy-four percent indicated 'most' or 'all' of their patients needed HCBS in the past 12 months. The most common needs were personal care (84%) and medication adherence (40%), and caregiver support (38%). Of the 86% of practices reporting they coordinate HCBS, 91% followed-up with patients, 84% assisted with applications, and 83% made service referrals. Fifty-seven percent reported that coordination was 'difficult.' The most common barriers to coordinating HCBS included cost to patient (65%), and eligibility requirements (63%). Four of the five most frequently reported barriers were associated with practices reporting it was 'difficult' or 'very difficult' to coordinate HCBS (OR from 2.49 to 3.94, p-values < .05)., Conclusions: Despite the barriers to addressing non-medical social needs, most HBPC practices provided some level of coordination of HCBS for their high-need, high-cost homebound patients. More efforts are needed to implement and scale care model partnerships between medical and non-medical service providers within HBPC practices.
- Published
- 2018
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27. Balancing macronutrient stoichiometry to alleviate eutrophication.
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Stutter MI, Graeber D, Evans CD, Wade AJ, and Withers PJA
- Abstract
Reactive nitrogen (N) and phosphorus (P) inputs to surface waters modify aquatic environments, affect public health and recreation. Source controls dominate eutrophication management, whilst biological regulation of nutrients is largely neglected, although aquatic microbial organisms have huge potential to process nutrients. The stoichiometric ratio of organic carbon (OC) to N to P atoms should modulate heterotrophic pathways of aquatic nutrient processing, as high OC availability favours aquatic microbial processing. Heterotrophic microbial processing removes N by denitrification and captures N and P as organically-complexed, less eutrophying forms. With a global data synthesis, we show that the atomic ratios of bioavailable dissolved OC to either N or P in rivers with urban and agricultural land use are often distant from a "microbial optimum". This OC-deficiency relative to high availabilities of N and P likely overwhelms within-river heterotrophic processing. We propose that the capability of streams and rivers to retain N and P may be improved by active stoichiometric rebalancing. Although autotrophic OC production contributes to heterotrophic rates substantial control on nutrient processing from allochthonous OC is documented for N and an emerging field for P. Hence, rebalancing should be done by reconnecting appropriate OC sources such as wetlands and riparian forests that have become disconnected from rivers concurrent with agriculture and urbanisation. However, key knowledge gaps require research prior to the safe implementation of this approach in management: (i) to evaluate system responses to catchment inputs of dissolved OC forms and amounts relative to internal production of autotrophic dissolved OC and aquatic and terrestrial particulate OC and (ii) evaluate risk factors in anoxia-mediated P desorption with elevated OC scenarios. Still, we find stoichiometric rebalancing through reconnecting landscape beneficial OC sources has considerable potential for river management to alleviate eutrophication, improve water quality and aquatic ecosystem health, if augmenting nutrient source control., (Copyright © 2018 Elsevier B.V. All rights reserved.)
- Published
- 2018
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28. Aiming for elimination: Outcomes of a consultation pathway supporting regional general practitioners to prescribe direct-acting antiviral therapy for hepatitis C.
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Wade AJ, McCormack A, Roder C, McDonald K, Davies M, Scott N, Wardrop M, Athan E, and Hellard ME
- Subjects
- Adult, Australia, Female, Humans, Male, Middle Aged, RNA, Viral blood, Retrospective Studies, Sustained Virologic Response, Treatment Outcome, Antiviral Agents therapeutic use, General Practitioners, Health Services Accessibility, Hepatitis C, Chronic drug therapy, Patient Acceptance of Health Care, Remote Consultation organization & administration, Remote Consultation statistics & numerical data
- Abstract
To increase access to treatment, the Australian government enabled general practitioners (GPs) to prescribe direct-acting antivirals (DAAs) to treat hepatitis C virus (HCV)-in consultation with a specialist if inexperienced in HCV management. This study describes the establishment and outcomes of a remote consultation pathway supporting GPs to treat HCV. Key stakeholders from primary and tertiary healthcare services in the Barwon South Western region developed and implemented an HCV remote consultation pathway. Pharmaceutical Benefits Schedule prescription data were used to evaluate GP DAA prescription 12 months pre-and post- pathway implementation. A retrospective review of patients referred for remote consultation for 12 months post- pathway inception was undertaken to determine the care cascade. HCV treatment initiation by GPs increased after implementation of the remote consultation pathway. In the 12-month study period, 74 GPs referred 169 people for remote consultation; 114 (67%) were approved for GP DAA treatment; 48 (28%) were referred for specialist assessment. In total, 119 (71%) patients commenced DAA; 69 were eligible for SVR12 assessment. Post-treatment HCV RNA data were available for 52 (75%) people; 37 achieved SVR12; 15 achieved SVR ranging from week 5 to 11 post-treatment. No treatment failure was detected. Collaborative development and implementation of a remote consultation pathway has engaged regional GPs in managing HCV. Follow-up post-treatment could be improved; however, no treatment failure has been documented. To eliminate HCV as a public health threat, it is vital that specialists support GPs to prescribe DAA., (© 2018 John Wiley & Sons Ltd.)
- Published
- 2018
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29. Community-based provision of direct-acting antiviral therapy for hepatitis C: study protocol and challenges of a randomized controlled trial.
- Author
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Wade AJ, Doyle JS, Gane E, Stedman C, Draper B, Iser D, Roberts SK, Kemp W, Petrie D, Scott N, Higgs P, Agius PA, Roney J, Stothers L, Thompson AJ, and Hellard ME
- Subjects
- Adult, Humans, Outcome Assessment, Health Care, Sample Size, Antiviral Agents therapeutic use, Community Health Services, Hepatitis C drug therapy, Randomized Controlled Trials as Topic
- Abstract
Background: To achieve the World Health Organization hepatitis C virus (HCV) elimination targets, it is essential to increase access to treatment. Direct-acting antiviral (DAA) treatment can be provided in primary healthcare services (PHCS), improving accessibility, and, potentially, retention in care. Here, we describe our protocol for assessing the effectiveness of providing DAAs in PHCS, and the impact on the HCV care cascade. In addition, we reflect on the challenges of conducting a model of care study during a period of unprecedented change in HCV care and treatment., Methods: Consenting patients with HCV infection attending 13 PHCS in Australia or New Zealand are randomized to receive DAA treatment at the local tertiary institution (standard care arm), or their PHCS (intervention arm). The primary endpoint is the proportion commenced on DAAs and cured. Treatment providers at the PHCS include: hepatology nurses, primary care practitioners, or, in two sites, a specialist physician. All PHCS offer opioid substitution therapy., Discussion: The Prime Study is the first real-world, randomized, model of care study exploring the impact of community provision of DAA therapy on HCV-treatment uptake and cure. Although the study has faced challenges unique to this period of time characterized by changing treatment and service delivery, the data gained will be of critical importance in shaping health service policy that enables the elimination of HCV., Trial Registration: ClinicalTrials.gov , ID: NCT02555475 . Registered on 15 September 2015.
- Published
- 2018
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30. Health issues of refugees attending an infectious disease refugee health clinic in a regional Australian hospital
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Masters PJ, Lanfranco PJ, Sneath E, Wade AJ, Huffam S, Pollard J, Standish J, McCloskey K, Athan E, O'Brien DP, and Friedman ND
- Subjects
- Altruism, Australia epidemiology, Avitaminosis diagnosis, Avitaminosis epidemiology, Communicable Diseases epidemiology, Hepatitis B diagnosis, Hepatitis B epidemiology, Humans, Latent Tuberculosis diagnosis, Latent Tuberculosis epidemiology, Retrospective Studies, Rural Population statistics & numerical data, Schistosomiasis diagnosis, Schistosomiasis epidemiology, Communicable Diseases diagnosis
- Abstract
Background and Objectives: Refugees in Australia present with conditions different to those of the general population. The aim of this study was to review the reasons for referral, prevalence of conditions and treatment outcomes for refugee patients attending a specialist referral clinic in regional Victoria., Method: A retrospective review was undertaken of patients attending the refugee health clinic at University Hospital Geelong from January 2007 to December 2012., Results: Two hundred and ninety-one refugee patients attended the clinic over the six-year period. Latent tuberculosis infection (LTBI) (54.6%), vitamin deficiencies (15.8%), hepatitis B (11%) and schistosomiasis (11%) were the most common diagnoses. Less than two-thirds of the patients completed LTBI treatment; 35.4% of patients attended all scheduled clinic appointments., Discussion: LTBI, vitamin deficiencies, parasitic infections and hepatitis B were the most common diagnoses among refugees referred to the University Hospital Geelong (UHG) Refugee Health Clinic from January 2007 to December 2012. General practitioners play an important role in the care of refugees, guiding referral to specialist services when necessary and recognising the potential implications of suboptimal clinic attendance and treatment completion.
- Published
- 2018
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31. Responses of Aquatic Plants to Eutrophication in Rivers: A Revised Conceptual Model.
- Author
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O'Hare MT, Baattrup-Pedersen A, Baumgarte I, Freeman A, Gunn IDM, Lázár AN, Sinclair R, Wade AJ, and Bowes MJ
- Abstract
Compared to research on eutrophication in lakes, there has been significantly less work carried out on rivers despite the importance of the topic. However, over the last decade, there has been a surge of interest in the response of aquatic plants to eutrophication in rivers. This is an area of applied research and the work has been driven by the widespread nature of the impacts and the significant opportunities for system remediation. A conceptual model has been put forward to describe how aquatic plants respond to eutrophication. Since the model was created, there have been substantial increases in our understanding of a number of the underlying processes. For example, we now know the threshold nutrient concentrations at which nutrients no longer limit algal growth. We also now know that the physical habitat template of rivers is a primary selector of aquatic plant communities. As such, nutrient enrichment impacts on aquatic plant communities are strongly influenced, both directly and indirectly, by physical habitat. A new conceptual model is proposed that incorporates these findings. The application of the model to management, system remediation, target setting, and our understanding of multi-stressor systems is discussed. We also look to the future and the potential for new numerical models to guide management.
- Published
- 2018
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32. Modelling the bioaccumulation of persistent organic pollutants in agricultural food chains for regulatory exposure assessment.
- Author
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Takaki K, Wade AJ, and Collins CD
- Subjects
- Agriculture, Animals, Biodiversity, Cattle, Milk chemistry, Milk metabolism, Plants chemistry, Plants metabolism, Soil chemistry, Soil Pollutants metabolism, Food Chain, Soil Pollutants analysis
- Abstract
New models for estimating bioaccumulation of persistent organic pollutants in the agricultural food chain were developed using recent improvements to plant uptake and cattle transfer models. One model named AgriSim was based on K
OW regressions of bioaccumulation in plants and cattle, while the other was a steady-state mechanistic model, AgriCom. The two developed models and European Union System for the Evaluation of Substances (EUSES), as a benchmark, were applied to four reported food chain (soil/air-grass-cow-milk) scenarios to evaluate the performance of each model simulation against the observed data. The four scenarios considered were as follows: (1) polluted soil and air, (2) polluted soil, (3) highly polluted soil surface and polluted subsurface and (4) polluted soil and air at different mountain elevations. AgriCom reproduced observed milk bioaccumulation well for all four scenarios, as did AgriSim for scenarios 1 and 2, but EUSES only did this for scenario 1. The main causes of the deviation for EUSES and AgriSim were the lack of the soil-air-plant pathway and the ambient air-plant pathway, respectively. Based on the results, it is recommended that soil-air-plant and ambient air-plant pathway should be calculated separately and the KOW regression of transfer factor to milk used in EUSES be avoided. AgriCom satisfied the recommendations that led to the low residual errors between the simulated and the observed bioaccumulation in agricultural food chain for the four scenarios considered. It is therefore recommended that this model should be incorporated into regulatory exposure assessment tools. The model uncertainty of the three models should be noted since the simulated concentration in milk from 5th to 95th percentile of the uncertainty analysis often varied over two orders of magnitude. Using a measured value of soil organic carbon content was effective to reduce this uncertainty by one order of magnitude.- Published
- 2017
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33. Modelling impacts of atmospheric deposition and temperature on long-term DOC trends.
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Sawicka K, Rowe EC, Evans CD, Monteith DT, E I Vanguelova, Wade AJ, and J M Clark
- Abstract
It is increasingly recognised that widespread and substantial increases in Dissolved organic carbon (DOC) concentrations in remote surface, and soil, waters in recent decades are linked to declining acid deposition. Effects of rising pH and declining ionic strength on DOC solubility have been proposed as potential dominant mechanisms. However, since DOC in these systems is derived mainly from recently-fixed carbon, and since organic matter decomposition rates are considered sensitive to temperature, uncertainty persists over the extent to which other drivers that could influence DOC production. Such potential drivers include fertilisation by nitrogen (N) and global warming. We therefore ran the dynamic soil chemistry model MADOC for a range of UK soils, for which time series data are available, to consider the likely relative importance of decreased deposition of sulphate and chloride, accumulation of reactive N, and higher temperatures, on soil DOC production in different soils. Modelled patterns of DOC change generally agreed favourably with measurements collated over 10-20years, but differed markedly between sites. While the acidifying effect of sulphur deposition appeared to be the predominant control on the observed soil water DOC trends in all the soils considered other than a blanket peat, the model suggested that over the long term, the effects of nitrogen deposition on N-limited soils may have been sufficient to raise the "acid recovery DOC baseline" significantly. In contrast, reductions in non-marine chloride deposition and effects of long term warming appeared to have been relatively unimportant. The suggestion that future DOC concentrations might exceed preindustrial levels as a consequence of nitrogen pollution has important implications for drinking water catchment management and the setting and pursuit of appropriate restoration targets, but findings still require validation from reliable centennial-scale proxy records, such as those being developed using palaeolimnological techniques., (Copyright © 2016 Elsevier B.V. All rights reserved.)
- Published
- 2017
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34. False positive and false negative errors in the design and implementation of agri-environmental policies: A case study on water quality and agricultural nutrients.
- Author
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Psaltopoulos D, Wade AJ, Skuras D, Kernan M, Tyllianakis E, and Erlandsson M
- Subjects
- Climate Change, Decision Making, Greece, Models, Theoretical, Research Design, Agriculture, Environmental Policy, Water Quality
- Abstract
When designing and implementing agri-environmental policies to reduce nutrient loss, action programmes may falsely address areas where the nutrient issue from agricultural activity is not currently important and is not likely to become so in the future (a false positive), or may fail to address areas where the agricultural nutrient issue is currently important or may likely become so in the future (a false negative). Based on a case study of the Louros watershed in Greece, this work identifies database and modelling sources of false positives and negatives and proposes a decision making process aimed at minimizing the possibility of committing such errors. The baseline is well simulated and shows that the Louro's watershed falls behind a Good Environmental Status, at least marginally. Simulated mitigation measures show that the river's status can be upgraded to "Good", at least as concerns nitrates and ammonium. Simulated climate change does not seem to exert an important positive or negative effect. Land use changes forecasting considerably less cultivated area have a significant effect on Total Phosphorous but not on nitrates or ammonium concentrations. The non-linearity between nutrient disposition (inputs) and nutrient concentration in downstream water bodies (output) and the many factors that affect the nutrient disposition-transportation-concentration chain, highlights the importance of simulating the effects of mitigation actions and of future climate and land use changes before adopting and establishing agri-environmental measures., (Copyright © 2016 Elsevier B.V. All rights reserved.)
- Published
- 2017
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35. Sensors in the Stream: The High-Frequency Wave of the Present.
- Author
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Rode M, Wade AJ, Cohen MJ, Hensley RT, Bowes MJ, Kirchner JW, Arhonditsis GB, Jordan P, Kronvang B, Halliday SJ, Skeffington RA, Rozemeijer JC, Aubert AH, Rinke K, and Jomaa S
- Subjects
- Temperature, Water Quality, Hydrology, Rivers
- Abstract
New scientific understanding is catalyzed by novel technologies that enhance measurement precision, resolution or type, and that provide new tools to test and develop theory. Over the last 50 years, technology has transformed the hydrologic sciences by enabling direct measurements of watershed fluxes (evapotranspiration, streamflow) at time scales and spatial extents aligned with variation in physical drivers. High frequency water quality measurements, increasingly obtained by in situ water quality sensors, are extending that transformation. Widely available sensors for some physical (temperature) and chemical (conductivity, dissolved oxygen) attributes have become integral to aquatic science, and emerging sensors for nutrients, dissolved CO
2 , turbidity, algal pigments, and dissolved organic matter are now enabling observations of watersheds and streams at time scales commensurate with their fundamental hydrological, energetic, elemental, and biological drivers. Here we synthesize insights from emerging technologies across a suite of applications, and envision future advances, enabled by sensors, in our ability to understand, predict, and restore watershed and stream systems.- Published
- 2016
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36. Riparian shading controls instream spring phytoplankton and benthic algal growth.
- Author
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Halliday SJ, Skeffington RA, Wade AJ, Bowes MJ, Read DS, Jarvie HP, and Loewenthal M
- Subjects
- Autotrophic Processes, Conservation of Natural Resources, England, Environmental Monitoring, Heterotrophic Processes, Nitrates analysis, Phosphates analysis, Seasons, Chlorophyta growth & development, Ecosystem, Eutrophication, Phytoplankton growth & development, Rivers, Sunlight, Trees growth & development
- Abstract
Dissolved oxygen (DO) concentrations showed a striking pattern in a multi-year study of the River Enborne, a small river in SE England. In each of three years (2010-2012), maximum DO concentrations were attained in mid-April, preceded by a period of steadily increasing diurnal amplitudes, followed by a steady reduction in both amplitude and concentration. Flow events during the reduction period reduce DO to low concentrations until the following spring. Evidence is presented that this pattern is mainly due to benthic algal growth which is eventually suppressed by the growth of the riparian tree canopy. Nitrate and silicate concentrations are too high to inhibit the growth of either benthic algae or phytoplankton, but phosphate concentrations might have started to reduce growth if the tree canopy development had been delayed. This interpretation is supported by evidence from weekly flow cytometry measurements and analysis of the diurnal, seasonal and annual patterns of nutrient concentrations. As the tree canopy develops, the river switches from an autotrophic to a heterotrophic state. The results support the use of riparian shading to help control algal growth, and highlight the risks of reducing riparian shade.
- Published
- 2016
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37. A systematic review of community based hepatitis C treatment.
- Author
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Wade AJ, Veronese V, Hellard ME, and Doyle JS
- Subjects
- Drug Therapy, Combination, Genotype, Hepacivirus drug effects, Hepacivirus genetics, Hepatitis C virology, Humans, Interferon-alpha therapeutic use, Ribavirin therapeutic use, Tertiary Care Centers, Treatment Outcome, Antiviral Agents therapeutic use, Hepatitis C drug therapy
- Abstract
Background: Hepatitis C virus (HCV) treatment uptake globally is low. A barrier to treatment is the necessity to attend specialists, usually in a tertiary hospital. We investigate the literature to assess the effect of providing HCV treatment in the community on treatment uptake and cure., Methods: Three databases were searched for studies that contained a comparison between HCV treatment uptake or sustained virologic response (SVR) in a community site and a tertiary site. Treatment was with standard interferon with or without ribavirin, or pegylated interferon and ribavirin. A narrative synthesis was conducted., Results: Thirteen studies fulfilled the inclusion criteria. Six studies measured treatment uptake; three demonstrated an increase in uptake at the community site, two demonstrated similar rates between sites and one demonstrated decreased uptake at the community site. Nine studies measured SVR; four demonstrated higher SVR rates in the community, four demonstrated similar SVR rates, and one demonstrated inferior SVR rates in the community compared to the tertiary site., Conclusion: The data available supports the efficacy of HCV treatment in the community, and the potential for community based treatment to increase treatment uptake. Whilst further studies are required, these findings highlight the potential benefit of providing community based HCV care - benefits that should be realised as interferon-free therapy become available. (PROSPERO registration number CRD42015025505).
- Published
- 2016
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38. The Cascade of Care for an Australian Community-Based Hepatitis C Treatment Service.
- Author
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Wade AJ, Macdonald DM, Doyle JS, Gordon A, Roberts SK, Thompson AJ, and Hellard ME
- Subjects
- Adult, Australia epidemiology, Female, Hepacivirus drug effects, Hepacivirus isolation & purification, Hepatitis C epidemiology, Hepatitis C pathology, Humans, Liver Cirrhosis complications, Liver Cirrhosis drug therapy, Liver Cirrhosis pathology, Liver Cirrhosis virology, Male, Retrospective Studies, Antiviral Agents therapeutic use, Community Health Services, Hepatitis C complications, Hepatitis C drug therapy, Medication Adherence, Substance Abuse, Intravenous complications
- Abstract
Background: Hepatitis C treatment uptake in Australia is low. To increase access to hepatitis C virus treatment for people who inject drugs, we developed a community-based, nurse-led service that linked a viral hepatitis service in a tertiary hospital to primary care clinics, and resulted in hepatitis C treatment provision in the community., Methods: A retrospective cohort study of patients referred to the community hepatitis service was undertaken to determine the cascade of care. Logistic regression analyses were used to identify predictors of hepatitis C treatment uptake., Results: Four hundred and sixty-two patients were referred to the community hepatitis service; 344 attended. Among the 279 attendees with confirmed chronic hepatitis C, 257 (99%) reported ever injecting drugs, and 124 (48%) injected in the last month. Of 201 (72%) patients who had their fibrosis staged, 63 (31%) had F3-F4 fibrosis. Fifty-five patients commenced hepatitis C treatment; 26 (47%) were current injectors and 25 (45%) had F3-F4 fibrosis. Nineteen of the 27 (70%) genotype 1 patients and 14 of the 26 (54%) genotype 3 patients eligible for assessment achieved a sustained virologic response. Advanced fibrosis was a significant predictor of treatment uptake in adjusted analysis (AOR 2.56, CI 1.30-5.00, p = 0.006)., Conclusions: Our community hepatitis service produced relatively high rates of fibrosis assessment, hepatitis C treatment uptake and cure, among people who inject drugs. These findings highlight the potential benefits of providing community-based hepatitis C care to people who inject drugs in Australia-benefits that should be realised as direct-acting antiviral agents become available.
- Published
- 2015
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39. Assessment and improvement of biotransfer models to cow's milk and beef used in exposure assessment tools for organic pollutants.
- Author
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Takaki K, Wade AJ, and Collins CD
- Subjects
- Animals, Environmental Pollutants chemistry, Fishes metabolism, Humans, Organic Chemicals chemistry, Quantitative Structure-Activity Relationship, Risk Assessment, Environmental Exposure analysis, Environmental Pollutants metabolism, Milk metabolism, Models, Biological, Organic Chemicals metabolism, Red Meat
- Abstract
The aim of this study was to assess and improve the accuracy of biotransfer models for the organic pollutants (PCBs, PCDD/Fs, PBDEs, PFCAs, and pesticides) into cow's milk and beef used in human exposure assessment. Metabolic rate in cattle is known as a key parameter for this biotransfer, however few experimental data and no simulation methods are currently available. In this research, metabolic rate was estimated using existing QSAR biodegradation models of microorganisms (BioWIN) and fish (EPI-HL and IFS-HL). This simulated metabolic rate was then incorporated into the mechanistic cattle biotransfer models (RAIDAR, ACC-HUMAN, OMEGA, and CKow). The goodness of fit tests showed that RAIDAR, ACC-HUMAN, OMEGA model performances were significantly improved using either of the QSARs when comparing the new model outputs to observed data. The CKow model is the only one that separates the processes in the gut and liver. This model showed the lowest residual error of all the models tested when the BioWIN model was used to represent the ruminant metabolic process in the gut and the two fish QSARs were used to represent the metabolic process in the liver. Our testing included EUSES and CalTOX which are KOW-regression models that are widely used in regulatory assessment. New regressions based on the simulated rate of the two metabolic processes are also proposed as an alternative to KOW-regression models for a screening risk assessment. The modified CKow model is more physiologically realistic, but has equivalent usability to existing KOW-regression models for estimating cattle biotransfer of organic pollutants., (Copyright © 2015. Published by Elsevier Ltd.)
- Published
- 2015
- Full Text
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40. Characterising phosphorus and nitrate inputs to a rural river using high-frequency concentration-flow relationships.
- Author
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Bowes MJ, Jarvie HP, Halliday SJ, Skeffington RA, Wade AJ, Loewenthal M, Gozzard E, Newman JR, and Palmer-Felgate EJ
- Abstract
The total reactive phosphorus (TRP) and nitrate concentrations of the River Enborne, southern England, were monitored at hourly interval between January 2010 and December 2011. The relationships between these high-frequency nutrient concentration signals and flow were used to infer changes in nutrient source and dynamics through the annual cycle and each individual storm event, by studying hysteresis patterns. TRP concentrations exhibited strong dilution patterns with increasing flow, and predominantly clockwise hysteresis through storm events. Despite the Enborne catchment being relatively rural for southern England, TRP inputs were dominated by constant, non-rain-related inputs from sewage treatment works (STW) for the majority of the year, producing the highest phosphorus concentrations through the spring-summer growing season. At higher river flows, the majority of the TRP load was derived from within-channel remobilisation of phosphorus from the bed sediment, much of which was also derived from STW inputs. Therefore, future phosphorus mitigation measures should focus on STW improvements. Agricultural diffuse TRP inputs were only evident during storms in the May of each year, probably relating to manure application to land. The nitrate concentration-flow relationship produced a series of dilution curves, indicating major inputs from groundwater and to a lesser extent STW. Significant diffuse agricultural inputs with anticlockwise hysteresis trajectories were observed during the first major storms of the winter period. The simultaneous investigation of high-frequency time series data, concentration-flow relationships and hysteresis behaviour through multiple storms for both phosphorus and nitrate offers a simple and innovative approach for providing new insights into nutrient sources and dynamics., (Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.)
- Published
- 2015
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41. Assessment of plant uptake models used in exposure assessment tools for soils contaminated with organic pollutants.
- Author
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Takaki K, Wade AJ, and Collins CD
- Subjects
- Calibration, Carbon analysis, Hydrophobic and Hydrophilic Interactions, Plant Roots drug effects, Plant Roots metabolism, Plant Shoots drug effects, Plant Shoots metabolism, Plant Transpiration drug effects, Plants drug effects, Soil chemistry, Soil Pollutants analysis, Soil Pollutants chemistry, Uncertainty, Environmental Exposure analysis, Models, Theoretical, Plants metabolism, Soil Pollutants pharmacokinetics
- Abstract
The aim of this study was to evaluate and improve the accuracy of plant uptake models for neutral hydrophobic organic pollutants (1 < logK(OW) < 9, -8 < logK(AW) < 0) used in regulatory exposure assessment tools, using uncertainty and sensitivity analyses. The models considered were RAIDAR, EUSES, CSOIL, CLEA, and CalTOX. In this research, CSOIL demonstrated the best performance of all five exposure assessment tools for root uptake from polluted soil in comparison with observed data, but no model predicted shoot uptake well. Recalibration of the transpiration and volatilisation parameters improved the performance of CSOIL and CLEA. The dominant pathway for shoot uptake simulated differed according to the properties of the chemical under consideration; those with a higher air-water partition coefficient were transported into shoots via the soil-air-plant pathway, while chemicals with a lower octanol-water partition coefficient and air-water partition coefficient were transported via the root. The soil organic carbon content was a particularly sensitive parameter in each model and using a site specific value improved model performance.
- Published
- 2014
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42. The potential for archiving and reconstituting valuable strains of turkey (Meleagris gallopavo) using primordial germ cells.
- Author
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Wade AJ, French NA, and Ireland GW
- Subjects
- Animals, Chimera embryology, Cryopreservation veterinary, Germ Cells growth & development, Gonads cytology, Gonads embryology, Cryopreservation methods, Embryo, Nonmammalian chemistry, Germ Cells cytology, Turkeys embryology, Turkeys genetics
- Abstract
Diseases such as avian influenza can destroy turkey flocks, potentially resulting in the loss of valuable or rare genetic material. Consequently, there is an urgent need to develop a means to archive such germplasm. Germline chimeras produced by intravascular transfer of primordial germ cells (PGC) have been reported in other avian species but not turkeys. This study examined the feasibility of both establishing an archive of frozen PGC, and producing germline chimeras by injecting the thawed PGC into host embryos. To meet these aims, the following experiments were performed: (1) PGC identification within turkey embryos; (2) development of an efficient method for isolation of turkey PGC; (3) demonstration that PGC can be cryopreserved, recovered, and retain viability; (4) reinjection into embryos and detection of injected PGC. Primordial germ cells were identified using periodic acid-Schiff reagent and the immunological marker OLP-1. Bloodstream PGC were isolated using Ficoll density gradient centrifugation with PGC recovery peaking at stages 13, 14, and 15 with 32 ± 4.9, 33 ± 6.4, and 26 ± 5.4 PGC recovered, respectively. Primordial germ cells were frozen using Dulbecco's modified Eagle medium, 20% fetal calf serum, and 10% dimethylsulfoxide and demonstrated 90 ± 1.7% viability after 3 mo frozen in liquid nitrogen. Freshly isolated and frozen thawed DiI- and Q-Tracker-labeled PGC repopulated stage 30 gonads after vascular transfer into ex ovo cultured embryos. The DiI-labeled cells repopulated gonads less frequently, with 36 ± 13.2% of gonads containing the DiI-labeled PGC, and 7 ± 3.8% of reinjected PGC reaching the gonads of positive embryos. The Q-tracker-labeled cells were detected more frequently in embryos, with 67 ± 21.1% having positive signals, and 44 ± 4.9% of reinjected Q-tracker-labeled PGC colonized the gonads of positive embryos. This study demonstrated the feasibility of using turkey PGC to archive turkey germplasm from different strains because frozen PGC reintroduced into host embryos can colonize the host gonads, suggesting the possibility of producing turkey germline chimeras.
- Published
- 2014
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43. A new method for producing transgenic birds via direct in vivo transfection of primordial germ cells.
- Author
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Tyack SG, Jenkins KA, O'Neil TE, Wise TG, Morris KR, Bruce MP, McLeod S, Wade AJ, McKay J, Moore RJ, Schat KA, Lowenthal JW, and Doran TJ
- Subjects
- Animals, Animals, Genetically Modified, Lipids genetics, Plasmids, Transfection methods, Chickens genetics, DNA Transposable Elements genetics, Gene Transfer Techniques, Germ Cells
- Abstract
Traditional methods of avian transgenesis involve complex manipulations involving either retroviral infection of blastoderms or the ex vivo manipulation of primordial germ cells (PGCs) followed by injection of the cells back into a recipient embryo. Unlike in mammalian systems, avian embryonic PGCs undergo a migration through the vasculature on their path to the gonad where they become the sperm or ova producing cells. In a development which simplifies the procedure of creating transgenic chickens we have shown that PGCs are directly transfectable in vivo using commonly available transfection reagents. We used Lipofectamine 2000 complexed with Tol2 transposon and transposase plasmids to stably transform PGCs in vivo generating transgenic offspring that express a reporter gene carried in the transposon. The process has been shown to be highly effective and as robust as the other methods used to create germ-line transgenic chickens while substantially reducing time, infrastructure and reagents required. The method described here defines a simple direct approach for transgenic chicken production, allowing researchers without extensive PGC culturing facilities or skills with retroviruses to produce transgenic chickens for wide-ranging applications in research, biotechnology and agriculture.
- Published
- 2013
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44. A cost-effectiveness analysis of water security and water quality: impacts of climate and land-use change on the River Thames system.
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Whitehead PG, Crossman J, Balana BB, Futter MN, Comber S, Jin L, Skuras D, Wade AJ, Bowes MJ, and Read DS
- Abstract
The catchment of the River Thames, the principal river system in southern England, provides the main water supply for London but is highly vulnerable to changes in climate, land use and population. The river is eutrophic with significant algal blooms with phosphorus assumed to be the primary chemical indicator of ecosystem health. In the Thames Basin, phosphorus is available from point sources such as wastewater treatment plants and from diffuse sources such as agriculture. In order to predict vulnerability to future change, the integrated catchments model for phosphorus (INCA-P) has been applied to the river basin and used to assess the cost-effectiveness of a range of mitigation and adaptation strategies. It is shown that scenarios of future climate and land-use change will exacerbate the water quality problems, but a range of mitigation measures can improve the situation. A cost-effectiveness study has been undertaken to compare the economic benefits of each mitigation measure and to assess the phosphorus reductions achieved. The most effective strategy is to reduce fertilizer use by 20% together with the treatment of effluent to a high standard. Such measures will reduce the instream phosphorus concentrations to close to the EU Water Framework Directive target for the Thames.
- Published
- 2013
- Full Text
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45. The interactive responses of water quality and hydrology to changes in multiple stressors, and implications for the long-term effective management of phosphorus.
- Author
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Crossman J, Whitehead PG, Futter MN, Jin L, Shahgedanova M, Castellazzi M, and Wade AJ
- Subjects
- Agriculture methods, Climate Change, Conservation of Natural Resources, England, Models, Theoretical, Sensitivity and Specificity, Phosphorus chemistry, Rivers chemistry, Water Movements, Water Pollution, Chemical prevention & control, Water Quality
- Abstract
Soluble reactive phosphorus (SRP) plays a key role in eutrophication, a global problem decreasing habitat quality and in-stream biodiversity. Mitigation strategies are required to prevent SRP fluxes from exceeding critical levels, and must be robust in the face of potential changes in climate, land use and a myriad of other influences. To establish the longevity of these strategies it is therefore crucial to consider the sensitivity of catchments to multiple future stressors. This study evaluates how the water quality and hydrology of a major river system in the UK (the River Thames) respond to alterations in climate, land use and water resource allocations, and investigates how these changes impact the relative performance of management strategies over an 80-year period. In the River Thames, the relative contributions of SRP from diffuse and point sources vary seasonally. Diffuse sources of SRP from agriculture dominate during periods of high runoff, and point sources during low flow periods. SRP concentrations rose under any future scenario which either increased a) surface runoff or b) the area of cultivated land. Under these conditions, SRP was sourced from agriculture, and the most effective single mitigation measures were those which addressed diffuse SRP sources. Conversely, where future scenarios reduced flow e.g. during winters of reservoir construction, the significance of point source inputs increased, and mitigation measures addressing these issues became more effective. In catchments with multiple point and diffuse sources of SRP, an all-encompassing effective mitigation approach is difficult to achieve with a single strategy. In order to attain maximum efficiency, multiple strategies might therefore be employed at different times and locations, to target the variable nature of dominant SRP sources and pathways., (Copyright © 2013 Elsevier B.V. All rights reserved.)
- Published
- 2013
- Full Text
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46. An analysis of long-term trends, seasonality and short-term dynamics in water quality data from Plynlimon, Wales.
- Author
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Halliday SJ, Wade AJ, Skeffington RA, Neal C, Reynolds B, Rowland P, Neal M, and Norris D
- Subjects
- Wales, Seasons, Water Quality
- Abstract
This paper examines two hydrochemical time-series derived from stream samples taken in the Upper Hafren catchment, Plynlimon, Wales. One time-series comprises data collected at 7-hour intervals over 22 months (Neal et al., 2012-this issue), while the other is based on weekly sampling over 20 years. A subset of determinands: aluminium, calcium, chloride, conductivity, dissolved organic carbon, iron, nitrate, pH, silicon and sulphate are examined within a framework of non-stationary time-series analysis to identify determinand trends, seasonality and short-term dynamics. The results demonstrate that both long-term and high-frequency monitoring provide valuable and unique insights into the hydrochemistry of a catchment. The long-term data allowed analysis of long-term trends, demonstrating continued increases in DOC concentrations accompanied by declining SO(4) concentrations within the stream, and provided new insights into the changing amplitude and phase of the seasonality of the determinands such as DOC and Al. Additionally, these data proved invaluable for placing the short-term variability demonstrated within the high-frequency data within context. The 7-hour data highlighted complex diurnal cycles for NO(3), Ca and Fe with cycles displaying changes in phase and amplitude on a seasonal basis. The high-frequency data also demonstrated the need to consider the impact that the time of sample collection can have on the summary statistics of the data and also that sampling during the hours of darkness provides additional hydrochemical information for determinands which exhibit pronounced diurnal variability. Moving forward, this research demonstrates the need for both long-term and high-frequency monitoring to facilitate a full and accurate understanding of catchment hydrochemical dynamics., (Copyright © 2011 Elsevier B.V. All rights reserved.)
- Published
- 2012
- Full Text
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47. Strengthening the link between climate, hydrological and species distribution modeling to assess the impacts of climate change on freshwater biodiversity.
- Author
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Tisseuil C, Vrac M, Grenouillet G, Wade AJ, Gevrey M, Oberdorff T, Grodwohl JB, and Lek S
- Subjects
- Animals, Biota, Climate, France, Water Movements, Climate Change, Conservation of Natural Resources methods, Ecosystem, Fishes physiology, Fresh Water, Models, Biological
- Abstract
To understand the resilience of aquatic ecosystems to environmental change, it is important to determine how multiple, related environmental factors, such as near-surface air temperature and river flow, will change during the next century. This study develops a novel methodology that combines statistical downscaling and fish species distribution modeling, to enhance the understanding of how global climate changes (modeled by global climate models at coarse-resolution) may affect local riverine fish diversity. The novelty of this work is the downscaling framework developed to provide suitable future projections of fish habitat descriptors, focusing particularly on the hydrology which has been rarely considered in previous studies. The proposed modeling framework was developed and tested in a major European system, the Adour-Garonne river basin (SW France, 116,000 km(2)), which covers distinct hydrological and thermal regions from the Pyrenees to the Atlantic coast. The simulations suggest that, by 2100, the mean annual stream flow is projected to decrease by approximately 15% and temperature to increase by approximately 1.2 °C, on average. As consequence, the majority of cool- and warm-water fish species is projected to expand their geographical range within the basin while the few cold-water species will experience a reduction in their distribution. The limitations and potential benefits of the proposed modeling approach are discussed., (Copyright © 2012 Elsevier B.V. All rights reserved.)
- Published
- 2012
- Full Text
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48. Modelling phosphorus dynamics in multi-branch river systems: a study of the Black River, Lake Simcoe, Ontario, Canada.
- Author
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Whitehead PG, Jin L, Baulch HM, Butterfield DA, Oni SK, Dillon PJ, Futter M, Wade AJ, North R, O'Connor EM, and Jarvie HP
- Subjects
- Conservation of Natural Resources, Ecosystem, Eutrophication, Lakes chemistry, Ontario, Seasons, Water Movements, Environmental Monitoring methods, Models, Chemical, Phosphorus chemistry, Rivers chemistry, Water Pollutants, Chemical chemistry
- Abstract
High rates of nutrient loading from agricultural and urban development have resulted in surface water eutrophication and groundwater contamination in regions of Ontario. In Lake Simcoe (Ontario, Canada), anthropogenic nutrient contributions have contributed to increased algal growth, low hypolimnetic oxygen concentrations, and impaired fish reproduction. An ambitious programme has been initiated to reduce phosphorus loads to the lake, aiming to achieve at least a 40% reduction in phosphorus loads by 2045. Achievement of this target necessitates effective remediation strategies, which will rely upon an improved understanding of controls on nutrient export from tributaries of Lake Simcoe as well as improved understanding of the importance of phosphorus cycling within the lake. In this paper, we describe a new model structure for the integrated dynamic and process-based model INCA-P, which allows fully-distributed applications, suited to branched river networks. We demonstrate application of this model to the Black River, a tributary of Lake Simcoe, and use INCA-P to simulate the fluxes of P entering the lake system, apportion phosphorus among different sources in the catchment, and explore future scenarios of land-use change and nutrient management to identify high priority sites for implementation of watershed best management practises., (Copyright © 2011 Elsevier B.V. All rights reserved.)
- Published
- 2011
- Full Text
- View/download PDF
49. A model-based assessment of the effects of projected climate change on the water resources of Jordan.
- Author
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Wade AJ, Black E, Brayshaw DJ, El-Bastawesy M, Holmes PA, Butterfield D, Nuimat S, and Jamjoum K
- Subjects
- Conservation of Natural Resources, Forecasting, Jordan, Models, Theoretical, Rivers, Seasons, Water Cycle physiology, Water Movements, Weather, Climate Change, Water Supply
- Abstract
This paper is concerned with the quantification of the likely effect of anthropogenic climate change on the water resources of Jordan by the end of the twenty-first century. Specifically, a suite of hydrological models are used in conjunction with modelled outcomes from a regional climate model, HadRM3, and a weather generator to determine how future flows in the upper River Jordan and in the Wadi Faynan may change. The results indicate that groundwater will play an important role in the water security of the country as irrigation demands increase. Given future projections of reduced winter rainfall and increased near-surface air temperatures, the already low groundwater recharge will decrease further. Interestingly, the modelled discharge at the Wadi Faynan indicates that extreme flood flows will increase in magnitude, despite a decrease in the mean annual rainfall. Simulations projected no increase in flood magnitude in the upper River Jordan. Discussion focuses on the utility of the modelling framework, the problems of making quantitative forecasts and the implications of reduced water availability in Jordan.
- Published
- 2010
- Full Text
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50. Sewage effluent clean-up reduces phosphorus but not phytoplankton in lowland chalk stream (River Kennet, UK) impacted by water mixing from adjacent canal.
- Author
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Neal C, Martin E, Neal M, Hallett J, Wickham HD, Harman SA, Armstrong LK, Bowes MJ, Wade AJ, and Keay D
- Subjects
- Calcium Carbonate chemistry, Chlorophyll analysis, Chlorophyll A, Environmental Monitoring, Eutrophication, Rivers chemistry, Sewage chemistry, Ships statistics & numerical data, United Kingdom, Water Movements, Environmental Restoration and Remediation methods, Phosphorus analysis, Phytoplankton growth & development, Waste Disposal, Fluid, Water Pollutants analysis
- Abstract
Information is provided on phosphorus in the River Kennet and the adjacent Kennet and Avon Canal in southern England to assess their interactions and the changes following phosphorus reductions in sewage treatment work (STW) effluent inputs. A step reduction in soluble reactive phosphorus (SRP) concentration within the effluent (5 to 13 fold) was observed from several STWs discharging to the river in the mid-2000s. This translated to over halving of SRP concentrations within the lower Kennet. Lower Kennet SRP concentrations change from being highest under base-flow to highest under storm-flow conditions. This represented a major shift from direct effluent inputs to a within-catchment source dominated system characteristic of the upper part to the catchment. Average SRP concentrations in the lower Kennet reduced over time towards the target for good water quality. Critically, there was no corresponding reduction in chlorophyll-a concentration, the waters remaining eutrophic when set against standards for lakes. Following the up gradient input of the main water and SRP source (Wilton Water), SRP concentrations in the canal reduced down gradient to below detection limits at times near its junction with the Kennet downstream. However, chlorophyll concentrations in the canal were in an order of magnitude higher than in the river. This probably resulted from long water residence times and higher temperatures promoting progressive algal and suspended sediment generations that consumed SRP. The canal acted as a point source for sediment, algae and total phosphorus to the river especially during the summer months when boat traffic disturbed the canal's bottom sediments and the locks were being regularly opened. The short-term dynamics of this transfer was complex. For the canal and the supply source at Wilton Water, conditions remained hypertrophic when set against standards for lakes even when SRP concentrations were extremely low., (Copyright © 2010 Elsevier B.V. All rights reserved.)
- Published
- 2010
- Full Text
- View/download PDF
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