- Joshi, Matina, Adhikari, Benu, Aldred, Peter, Panozzo, Joe, Kasapis, Stefan
- Authors: Joshi, Matina , Adhikari, Benu , Aldred, Peter , Panozzo, Joe , Kasapis, Stefan
- Date: 2011
- Type: Text , Journal article
- Relation: Food Chemistry Vol. 129, no. 4 (2011), p. 1513-1522
- Full Text: false
- Reviewed:
- Description: Lentil protein isolate (LPI) extract was converted into powder by freeze drying, spray drying and vacuum drying. Differences in particle size distribution, protein subunit composition and colour and surface morphology were observed amongst the three drying methods. Spray and freeze-dried LPI powders exhibited higher solubility (81% and 78%, respectively) compared to vacuum dried powders (50%). The spray dried powders showed a low water absorption capacity (0.43 ± 0.02 g/g) compared to freeze (0.48 ± 0.02 g/g) and vacuum-dried (0.47 ± 0.01 g/g) LPI powders. Spray and freeze-dried powders displayed better gelation ability and higher gel strength, compared to vacuum-dried powder. Both spray and freeze-dried gels showed typical viscoelastic gel characteristics, with G′ dominating over G″ and very low loss tangent. The holding time required for gelation of vacuum dried powder at 90 °C was significantly longer, compared to spray and freeze dried powders. Hence, drying methods used for preparation of lentil protein isolate powders can affect physicochemical and associated functional properties. © 2011 Elsevier Ltd. All rights reserved.
Interfacial and emulsifying properties of lentil protein isolate
- Joshi, Matina, Adhikari, Benu, Aldred, Peter, Panozzo, Joe, Kasapis, Stefan, Barrow, Colin
- Authors: Joshi, Matina , Adhikari, Benu , Aldred, Peter , Panozzo, Joe , Kasapis, Stefan , Barrow, Colin
- Date: 2012
- Type: Text , Journal article
- Relation: Food Chemistry Vol.134 no.3 (2012), p.343-1353
- Full Text:
- Reviewed:
- Description: The dynamic interfacial tension (DIFT) at oil-water interface, diffusion coefficients, surface hydrophobicity, zeta potential and emulsifying properties, including emulsion activity index (EAI), emulsion stability index (ESI) and droplet size of lentil protein isolate (LPI), were measured at different pH and LPI concentration, in order to elucidate its emulsifying behaviour. Sodium caseinate (NaCas), whey protein isolate (WPI), bovine serum albumin (BSA) and lysozyme (Lys) were used as benchmark proteins and their emulsifying property was compared with that of LPI. The speed of diffusion-controlled migration of these proteins to the oil/water interface, was in the following order: NaCas > LPI > WPI > BSA > Lys, while their surface hydrophobicity was in the following order: BSA > LPI > NaCas > WPI > Lys. The EAI of emulsions stabilised by the above proteins ranged from 90.3 to 123.3 m 2/g and it was 93.3 ± 0.2 m 2/g in LPI-stabilised emulsion. However, the stability of LPI-stabilised emulsions was slightly lower compared to that of WPI and NaCas-stabilised emulsions at the same protein concentration at pH 7.0. The ESI of LPI emulsions improved substantially with decrease in droplet size when protein concentration was increased (20-30 mg/ml). Reduction of disulphide bonds enhanced both the EAI and ESI compared to untreated samples. Heat treatment of LPI dispersions resulted in poor emulsion stability due to molecular aggregation. The stability of LPI-stabilised emulsions was found to decrease in the presence of NaCl. This study showed that LPI can be as effective emulsifiers of oil-in-water emulsions as are WPI and NaCas at ≥20 mg/ml concentrations both at low and neutral pH. The emulsifying property of LPI can be improved by reducing the intra and inter-disulphide bond by using appropriate reducing agents. © 2012 Elsevier Ltd. All rights reserved.
- Authors: Joshi, Matina , Adhikari, Benu , Aldred, Peter , Panozzo, Joe , Kasapis, Stefan , Barrow, Colin
- Date: 2012
- Type: Text , Journal article
- Relation: Food Chemistry Vol.134 no.3 (2012), p.343-1353
- Full Text:
- Reviewed:
- Description: The dynamic interfacial tension (DIFT) at oil-water interface, diffusion coefficients, surface hydrophobicity, zeta potential and emulsifying properties, including emulsion activity index (EAI), emulsion stability index (ESI) and droplet size of lentil protein isolate (LPI), were measured at different pH and LPI concentration, in order to elucidate its emulsifying behaviour. Sodium caseinate (NaCas), whey protein isolate (WPI), bovine serum albumin (BSA) and lysozyme (Lys) were used as benchmark proteins and their emulsifying property was compared with that of LPI. The speed of diffusion-controlled migration of these proteins to the oil/water interface, was in the following order: NaCas > LPI > WPI > BSA > Lys, while their surface hydrophobicity was in the following order: BSA > LPI > NaCas > WPI > Lys. The EAI of emulsions stabilised by the above proteins ranged from 90.3 to 123.3 m 2/g and it was 93.3 ± 0.2 m 2/g in LPI-stabilised emulsion. However, the stability of LPI-stabilised emulsions was slightly lower compared to that of WPI and NaCas-stabilised emulsions at the same protein concentration at pH 7.0. The ESI of LPI emulsions improved substantially with decrease in droplet size when protein concentration was increased (20-30 mg/ml). Reduction of disulphide bonds enhanced both the EAI and ESI compared to untreated samples. Heat treatment of LPI dispersions resulted in poor emulsion stability due to molecular aggregation. The stability of LPI-stabilised emulsions was found to decrease in the presence of NaCl. This study showed that LPI can be as effective emulsifiers of oil-in-water emulsions as are WPI and NaCas at ≥20 mg/ml concentrations both at low and neutral pH. The emulsifying property of LPI can be improved by reducing the intra and inter-disulphide bond by using appropriate reducing agents. © 2012 Elsevier Ltd. All rights reserved.
- Judkins, Courtney, Wang, Yutang, Jelinic, Maria, Bobik, Alex, Vinh, Antony, Sobey, Christopher, Drummond, Grant
- Authors: Judkins, Courtney , Wang, Yutang , Jelinic, Maria , Bobik, Alex , Vinh, Antony , Sobey, Christopher , Drummond, Grant
- Date: 2023
- Type: Text , Journal article
- Relation: Scientific Reports Vol. 13, no. 1 (2023), p.
- Full Text: false
- Reviewed:
- Description: The association between constipation and cardiovascular risk is unclear. This population-level matched cohort study compared the association of constipation with hypertension and incident cardiovascular events in 541,172 hospitalized patients aged
Trends in land use and land cover change in the protected and communal areas of the Zambezi Region, Namibia
- Kamwi, Jonathan, Kaetsch, Christoph, Graz, Patrick, Chirwa, Paxie, Manda, Samuel
- Authors: Kamwi, Jonathan , Kaetsch, Christoph , Graz, Patrick , Chirwa, Paxie , Manda, Samuel
- Date: 2017
- Type: Text , Journal article
- Relation: Environmental Monitoring and Assessment Vol. 189, no. 5 (2017), p. 1-18
- Full Text:
- Reviewed:
- Description: Land management decisions have extensively modified land use and land cover in the Zambezi Region. These decisions are influenced by land tenure classifications, legislation, and livelihoods. Land use and land cover change is an important indicator for quantifying the effectiveness of different land management strategies. However, there has been no evidence on whether protected or communal land tenure is more affected by land use and land cover changes in southern Africa and particularly Namibia. Our study attempted to fill this gap by analyzing the relationship between land use and land cover change and land tenure regimes stratified according to protected and communal area in the Zambezi Region. Multi-temporal Landsat TM and ETM+ imagery were used to determine the temporal dynamics of land use and land cover change from 1984 to 2010. The landscape showed distinctive modifications over the study period; broad trends include the increase in forest land after 1991. However, changes were not uniform across the study areas. Two landscape development stages were deduced: (1) 1984–1991 represented high deforestation and gradual increase in shrub land; (2) 1991–2000 and 2000–2010 represented lower deforestation and slower agropastoral expansion. The results further show clear patterns of the dynamics, magnitude, and direction of land use and land cover change by tenure regime. The study concluded that land tenure has a direct impact on land use and land cover, since it may restrict some activities carried out on the land in the Zambezi Region. © 2017, Springer International Publishing Switzerland.
- Authors: Kamwi, Jonathan , Kaetsch, Christoph , Graz, Patrick , Chirwa, Paxie , Manda, Samuel
- Date: 2017
- Type: Text , Journal article
- Relation: Environmental Monitoring and Assessment Vol. 189, no. 5 (2017), p. 1-18
- Full Text:
- Reviewed:
- Description: Land management decisions have extensively modified land use and land cover in the Zambezi Region. These decisions are influenced by land tenure classifications, legislation, and livelihoods. Land use and land cover change is an important indicator for quantifying the effectiveness of different land management strategies. However, there has been no evidence on whether protected or communal land tenure is more affected by land use and land cover changes in southern Africa and particularly Namibia. Our study attempted to fill this gap by analyzing the relationship between land use and land cover change and land tenure regimes stratified according to protected and communal area in the Zambezi Region. Multi-temporal Landsat TM and ETM+ imagery were used to determine the temporal dynamics of land use and land cover change from 1984 to 2010. The landscape showed distinctive modifications over the study period; broad trends include the increase in forest land after 1991. However, changes were not uniform across the study areas. Two landscape development stages were deduced: (1) 1984–1991 represented high deforestation and gradual increase in shrub land; (2) 1991–2000 and 2000–2010 represented lower deforestation and slower agropastoral expansion. The results further show clear patterns of the dynamics, magnitude, and direction of land use and land cover change by tenure regime. The study concluded that land tenure has a direct impact on land use and land cover, since it may restrict some activities carried out on the land in the Zambezi Region. © 2017, Springer International Publishing Switzerland.
Assessment of the impact of stormwater characteristics on clogging in stormwater filters
- Kandra, Harpreet, McCarthy, David, Deletic, Ana
- Authors: Kandra, Harpreet , McCarthy, David , Deletic, Ana
- Date: 2014
- Type: Text , Journal article
- Relation: Water Resources Management Vol. 29, no. 4 (2014), p. 1031-1048
- Full Text: false
- Reviewed:
- Description: Hydraulic conductivity of granular filter media and its evolution over time is a key design parameter for stormwater filtration and infiltration systems that are now widely used in management of polluted urban runoff. In fact, clogging of filter media is recognised as the main limiting factor of these stormwater treatment systems. This paper focuses on the effect of stormwater characteristics on the clogging of stormwater filters. Effect of five different operational regimes has been tested in this study of sediment concentration; pollutant concentrations; stormwater sediment size; loading rate and stormwater loading/dosing regime and compared with the Base case. For each operational condition, five column replicates were tested. Results suggest that sediment concentration in stormwater is a significant parameter affecting hydraulic and treatment performance, eventually affecting longevity of these stormwater treatment systems. Further, the size of sediments (and their relation to the size of filter media grains) in stormwater was found to be an important parameter to be considered in design of coarse filters with high infiltration rates that are used for stormwater treatment. As expected, the addition of metals and nutrients had limited or no contribution to changes in hydraulic or sediment removal performance of the studied stormwater filters. Whilst loading rate was found to be an important parameter affecting the hydraulic and treatment performance of these systems, any variation in the stormwater loading regime had a limited effect on their performance. This study therefore develops an understanding of the effect of catchment characteristics on design of filters and hence their longevity and maintenance needs. © 2014, Springer Science+Business Media Dordrecht.
Assessment of impact of filter design variables on clogging in stormwater filters
- Kandra, Harpreet, Deletic, Ana, McCarthy, David
- Authors: Kandra, Harpreet , Deletic, Ana , McCarthy, David
- Date: 2014
- Type: Text , Journal article
- Relation: Water Resources Management Vol. 28, no. 7 (2014), p. 1873-1885
- Full Text: false
- Reviewed:
- Description: Stormwater filters are widely used in stormwater management, sometimes as standalone structures (e.g. stormwater filter beds), or as part of porous pavements, soak ways, infiltration basins and trenches. Due to the high levels of sediment present in stormwater, clogging is the main operational issue for these systems. A laboratory-based study was conducted to investigate the effect of filter bed design variables on the clogging phenomenon in non-vegetated stormwater filters with high infiltration rates. Design parameters studied include: filter media particle sizes (0.5 mm, 2 mm, 5 mm); depth of the filter bed (100 mm, 300 mm and 500 mm); and filter media packing configurations (layered or mixed). The size of filter media particles significantly impact the clogging process, as well as the overall sediment removal performance of the filters; filters with smaller particles had better sediment removal efficiency, but subsequently shorter lifespan. Deeper systems had longer lifespan compared with shallower ones, notwithstanding deeper systems removed more sediment over their life span. Having two layers of distinct sized media in the filter bed improved performance (e.g. volume of water treated; sediment removed) over the single-layered systems. However, the three-layered systems behaved similarly to two-layered systems. Mixed systems also showed improved performance, as compared with single-layered systems, and were similar to the three-layered systems. This study therefore suggests that simple modifications to a stormwater filtration system can help improve sediment removal performance and/or reduce maintenance intervals significantly, while only slightly affecting sediment removal performance. © 2014 Springer Science+Business Media Dordrecht.
Assessment of clogging phenomena in granular filter media used for stormwater treatment
- Kandra, Harpreet, McCarthy, David, Fletcher, Tim, Deletic, Ana
- Authors: Kandra, Harpreet , McCarthy, David , Fletcher, Tim , Deletic, Ana
- Date: 2014
- Type: Text , Journal article
- Relation: Journal of Hydrology Vol. 512, no. (2014), p. 518-527
- Full Text:
- Reviewed:
- Description: Hydraulic performance of granular filter media and its evolution over time is a key design parameter for stormwater filtration and infiltration systems that are now widely used in management of polluted urban runoff. In fact, clogging of filter media is recognised as the main limiting factor of these stormwater treatment systems. This paper focuses on the effect of physical characteristics of filter media and flow-through rates on the clogging of stormwater filters. Five replicate experimental columns were constructed using zeolite, scoria, riversand and polymeric glass beads, and different flow-through rates were achieved using restricted outlets. The systems were dosed with semi-synthetic stormwater and the evolution of hydraulic performance and sediment removal rate was observed (for four filter media and across four flow rates) to investigate impacts of media type and flow rate. It was found that shape and smoothness of filter media grains had limited effect on clogging and sediment removal rate. All media except scoria clogged after similar volumes of stormwater but scoria-based filters were found to be highly variable in performance, most likely due to breakdown of its particles. Conversely, flow-through rate significantly affected clogging and sediment removal rate. For instance, in the case of zeolite filters, the systems with the lowest flow rate clogged after application of over 30. m of stormwater, while the unrestricted zeolite columns (with 200 times the flow rate) clogged after only 10. m of applied stormwater. At the same time, the zeolite filters with the lowest flow rate had an overall treatment efficiency of 88% compared with the unrestricted design's efficiency of 59%. Further work is needed to analyse the influence of filter bed design, stormwater inflow characteristics and drying and wetting regimes on clogging and to understand the location of the clogged material in these filters. © 2014 Elsevier B.V.
- Authors: Kandra, Harpreet , McCarthy, David , Fletcher, Tim , Deletic, Ana
- Date: 2014
- Type: Text , Journal article
- Relation: Journal of Hydrology Vol. 512, no. (2014), p. 518-527
- Full Text:
- Reviewed:
- Description: Hydraulic performance of granular filter media and its evolution over time is a key design parameter for stormwater filtration and infiltration systems that are now widely used in management of polluted urban runoff. In fact, clogging of filter media is recognised as the main limiting factor of these stormwater treatment systems. This paper focuses on the effect of physical characteristics of filter media and flow-through rates on the clogging of stormwater filters. Five replicate experimental columns were constructed using zeolite, scoria, riversand and polymeric glass beads, and different flow-through rates were achieved using restricted outlets. The systems were dosed with semi-synthetic stormwater and the evolution of hydraulic performance and sediment removal rate was observed (for four filter media and across four flow rates) to investigate impacts of media type and flow rate. It was found that shape and smoothness of filter media grains had limited effect on clogging and sediment removal rate. All media except scoria clogged after similar volumes of stormwater but scoria-based filters were found to be highly variable in performance, most likely due to breakdown of its particles. Conversely, flow-through rate significantly affected clogging and sediment removal rate. For instance, in the case of zeolite filters, the systems with the lowest flow rate clogged after application of over 30. m of stormwater, while the unrestricted zeolite columns (with 200 times the flow rate) clogged after only 10. m of applied stormwater. At the same time, the zeolite filters with the lowest flow rate had an overall treatment efficiency of 88% compared with the unrestricted design's efficiency of 59%. Further work is needed to analyse the influence of filter bed design, stormwater inflow characteristics and drying and wetting regimes on clogging and to understand the location of the clogged material in these filters. © 2014 Elsevier B.V.
New diagonal bundle method for clustering problems in large data sets
- Karmitsa, Napsu, Bagirov, Adil, Taheri, Sona
- Authors: Karmitsa, Napsu , Bagirov, Adil , Taheri, Sona
- Date: 2017
- Type: Text , Journal article
- Relation: European Journal of Operational Research Vol. 263, no. 2 (2017), p. 367-379
- Relation: http://purl.org/au-research/grants/arc/DP140103213
- Full Text: false
- Reviewed:
- Description: Clustering is one of the most important tasks in data mining. Recent developments in computer hardware allow us to store in random access memory (RAM) and repeatedly read data sets with hundreds of thousands and even millions of data points. This makes it possible to use conventional clustering algorithms in such data sets. However, these algorithms may need prohibitively large computational time and fail to produce accurate solutions. Therefore, it is important to develop clustering algorithms which are accurate and can provide real time clustering in large data sets. This paper introduces one of them. Using nonsmooth optimization formulation of the clustering problem the objective function is represented as a difference of two convex (DC) functions. Then a new diagonal bundle algorithm that explicitly uses this structure is designed and combined with an incremental approach to solve this problem. The method is evaluated using real world data sets with both large number of attributes and large number of data points. The proposed method is compared with two other clustering algorithms using numerical results. © 2017 Elsevier B.V.
Integration of palaeo-and-modern food webs reveal slow changes in a river floodplain wetland ecosystem
- Kattel, Giri, Eyre, Bradley, Gell, Peter
- Authors: Kattel, Giri , Eyre, Bradley , Gell, Peter
- Date: 2020
- Type: Text , Journal article
- Relation: Scientific Reports Vol. 10, no. 1 (2020), p.
- Full Text:
- Reviewed:
- Description: Large rivers, including the Murray River system in southeast Australia, are disturbed by many activities. The arrival of European settlers to Australia by the mid-1800s transformed many floodplain wetlands of the lower Murray River system. River impoundment and flow regulation in the late 1800s and, from the 1930s, resulted in species invasion, and elevated nutrient concentrations causing widespread eutrophication. An integrated palaeoecology, and palaeo-and-modern food web approach, incorporating mixing models, was undertaken to reveal changes in a regulated wetland (i.e. Kings Billabong). The lack of preserved sediment suggests the wetland was naturally intermittent before 1890. After this time, when used as a water retention basin, the wetland experienced net sediment accumulation. Subfossil cladocerans, and δ13C of Daphnia, chironomid, and bulk sediment, all reflected an early productive, likely clear water state and shifts in trophic state following river regulation in the 1930s. Food web mixing models, based on δ13C and δ15N in subfossil and modern Daphnia, fish, and submerged and emergent macrophytes, also indicated a shift in the trophic relationships between fish and Daphnia. By the 1970s, a new state was established but a further significant alteration of nitrogen and carbon sources, and trophic interactions, continued through to the early 2000s. A possible switch from Daphnia as a prey of Australian Smelt could have modified the food web of the wetland by c. 2006. The timing of this change corresponded to the expansion of emergent macrophytes possibly due to landscape level disruptions. The evidence of these changes suggests a need for a broader understanding of the evolution of wetlands for the management of floodplains in the region. © 2020, The Author(s).
- Description: Funding details: National Key Research and Development Program of China Stem Cell and Translational Research, #2016YFC0402900 Funding details: National Key Research and Development Program of China Stem Cell and Translational Research, #2016YFE0201900 Funding details: Centre of Excellence for Electromaterials Science, Australian Research Council, ARC;ACES, DP160100248 Funding details: Centre of Excellence for Electromaterials Science, Australian Research Council, ARC;ACES, LE0668495
- Authors: Kattel, Giri , Eyre, Bradley , Gell, Peter
- Date: 2020
- Type: Text , Journal article
- Relation: Scientific Reports Vol. 10, no. 1 (2020), p.
- Full Text:
- Reviewed:
- Description: Large rivers, including the Murray River system in southeast Australia, are disturbed by many activities. The arrival of European settlers to Australia by the mid-1800s transformed many floodplain wetlands of the lower Murray River system. River impoundment and flow regulation in the late 1800s and, from the 1930s, resulted in species invasion, and elevated nutrient concentrations causing widespread eutrophication. An integrated palaeoecology, and palaeo-and-modern food web approach, incorporating mixing models, was undertaken to reveal changes in a regulated wetland (i.e. Kings Billabong). The lack of preserved sediment suggests the wetland was naturally intermittent before 1890. After this time, when used as a water retention basin, the wetland experienced net sediment accumulation. Subfossil cladocerans, and δ13C of Daphnia, chironomid, and bulk sediment, all reflected an early productive, likely clear water state and shifts in trophic state following river regulation in the 1930s. Food web mixing models, based on δ13C and δ15N in subfossil and modern Daphnia, fish, and submerged and emergent macrophytes, also indicated a shift in the trophic relationships between fish and Daphnia. By the 1970s, a new state was established but a further significant alteration of nitrogen and carbon sources, and trophic interactions, continued through to the early 2000s. A possible switch from Daphnia as a prey of Australian Smelt could have modified the food web of the wetland by c. 2006. The timing of this change corresponded to the expansion of emergent macrophytes possibly due to landscape level disruptions. The evidence of these changes suggests a need for a broader understanding of the evolution of wetlands for the management of floodplains in the region. © 2020, The Author(s).
- Description: Funding details: National Key Research and Development Program of China Stem Cell and Translational Research, #2016YFC0402900 Funding details: National Key Research and Development Program of China Stem Cell and Translational Research, #2016YFE0201900 Funding details: Centre of Excellence for Electromaterials Science, Australian Research Council, ARC;ACES, DP160100248 Funding details: Centre of Excellence for Electromaterials Science, Australian Research Council, ARC;ACES, LE0668495
Healthy waterways and ecologically sustainable cities in Beijing-Tianjin-Hebei urban agglomeration (northern China) : challenges and future directions
- Kattel, Giri, Reeves, Jessica, Western, Andrew, Zhang, Wenjing, Dowling, Kim
- Authors: Kattel, Giri , Reeves, Jessica , Western, Andrew , Zhang, Wenjing , Dowling, Kim
- Date: 2021
- Type: Text , Journal article
- Relation: Wiley Interdisciplinary Reviews: Water Vol. 8, no. 2 (2021), p.
- Full Text:
- Reviewed:
- Description: The cities across the northern dry region of China are exposed to multiple sustainability challenges. Beijing-Hebei-Tianjin (BTH) urban agglomeration, for example, experiences severe water shortages due to rapidly expanding urban populations, industrial use, and irrigation-intensive agriculture. Climate change has further threatened water resources security. Overuse of water resources to meet the demand of various water sectors has far-reaching health and environmental implications including ecosystem sustainability. Surface water and groundwater pollution present public health risks. Despite the extraordinary policies and efforts being made and implemented by the Government of China, the BTH region currently lacks coordination among stakeholders leading to poor water governance. Consultation among scientists, engineers and stakeholders on regional water security issues is crucial and must be frequent and inclusive. An international symposium was held in Shijiazhuang in early November 2019 to identify some of the key water security challenges and scope of an idealized future eco-city in the region by developing a sustainability framework. This work drew on experiences from across China and beyond. Scientists agree that integration of science, technology, and governance within an appropriate policy framework was particularly significant for combating the issue of water insecurity, including in the region's newly developed city, Xiong'an New Area. An emerging concept, “Healthy Waterways and Ecologically Sustainable Cities” which integrates social, ecological and hydrological systems and acts as an important pathway for sustainability in the 21st century was proposed in the symposium to tackle the problems in the region. This high level biophysical and cultural concept empowers development goals and promotes human health and wellbeing. The framework on healthy waterways and ecologically sustainable cities can overcome sustainability challenges by resolving water resource management issues in BTH in a holistic way. To implement the concept, we strongly recommend the utilization of evidence-based scientific research and institutional cooperation including national and international collaborations to achieve the Healthy Waterways and Ecologically Sustainable Cities goal in the BTH in future. This article is categorized under: Water and Life > Conservation, Management, and Awareness. © 2020 Wiley Periodicals LLC. **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Giri Kattel, Jessica Reeves and Kim Dowling” is provided in this record**
- Authors: Kattel, Giri , Reeves, Jessica , Western, Andrew , Zhang, Wenjing , Dowling, Kim
- Date: 2021
- Type: Text , Journal article
- Relation: Wiley Interdisciplinary Reviews: Water Vol. 8, no. 2 (2021), p.
- Full Text:
- Reviewed:
- Description: The cities across the northern dry region of China are exposed to multiple sustainability challenges. Beijing-Hebei-Tianjin (BTH) urban agglomeration, for example, experiences severe water shortages due to rapidly expanding urban populations, industrial use, and irrigation-intensive agriculture. Climate change has further threatened water resources security. Overuse of water resources to meet the demand of various water sectors has far-reaching health and environmental implications including ecosystem sustainability. Surface water and groundwater pollution present public health risks. Despite the extraordinary policies and efforts being made and implemented by the Government of China, the BTH region currently lacks coordination among stakeholders leading to poor water governance. Consultation among scientists, engineers and stakeholders on regional water security issues is crucial and must be frequent and inclusive. An international symposium was held in Shijiazhuang in early November 2019 to identify some of the key water security challenges and scope of an idealized future eco-city in the region by developing a sustainability framework. This work drew on experiences from across China and beyond. Scientists agree that integration of science, technology, and governance within an appropriate policy framework was particularly significant for combating the issue of water insecurity, including in the region's newly developed city, Xiong'an New Area. An emerging concept, “Healthy Waterways and Ecologically Sustainable Cities” which integrates social, ecological and hydrological systems and acts as an important pathway for sustainability in the 21st century was proposed in the symposium to tackle the problems in the region. This high level biophysical and cultural concept empowers development goals and promotes human health and wellbeing. The framework on healthy waterways and ecologically sustainable cities can overcome sustainability challenges by resolving water resource management issues in BTH in a holistic way. To implement the concept, we strongly recommend the utilization of evidence-based scientific research and institutional cooperation including national and international collaborations to achieve the Healthy Waterways and Ecologically Sustainable Cities goal in the BTH in future. This article is categorized under: Water and Life > Conservation, Management, and Awareness. © 2020 Wiley Periodicals LLC. **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Giri Kattel, Jessica Reeves and Kim Dowling” is provided in this record**
Impact of traditional and embedded image denoising on CNN-based deep learning
- Kaur, Roopdeep, Karmakar, Gour, Imran, Muhammad
- Authors: Kaur, Roopdeep , Karmakar, Gour , Imran, Muhammad
- Date: 2023
- Type: Text , Journal article
- Relation: Applied sciences Vol. 13, no. 20 (2023), p.
- Full Text:
- Reviewed:
- Description: In digital image processing, filtering noise is an important step for reconstructing a high-quality image for further processing such as object segmentation, object detection, and object recognition. Various image-denoising approaches, including median, Gaussian, and bilateral filters, are available in the literature. Since convolutional neural networks (CNN) are able to directly learn complex patterns and features from data, they have become a popular choice for image-denoising tasks. As a result of their ability to learn and adapt to various denoising scenarios, CNNs are powerful tools for image denoising. Some deep learning techniques such as CNN incorporate denoising strategies directly into the CNN model layers. A primary limitation of these methods is their necessity to resize images to a consistent size. This resizing can result in a loss of vital image details, which might compromise CNN’s effectiveness. Because of this issue, we utilize a traditional denoising method as a preliminary step for noise reduction before applying CNN. To our knowledge, a comparative performance study of CNN using traditional and embedded denoising against a baseline approach (without denoising) is yet to be performed. To analyze the impact of denoising on the CNN performance, in this paper, firstly, we filter the noise from the images using traditional means of denoising method before their use in the CNN model. Secondly, we embed a denoising layer in the CNN model. To validate the performance of image denoising, we performed extensive experiments for both traffic sign and object recognition datasets. To decide whether denoising will be adopted and to decide on the type of filter to be used, we also present an approach exploiting the peak-signal-to-noise-ratio (PSNRs) distribution of images. Both CNN accuracy and PSNRs distribution are used to evaluate the effectiveness of the denoising approaches. As expected, the results vary with the type of filter, impact, and dataset used in both traditional and embedded denoising approaches. However, traditional denoising shows better accuracy, while embedded denoising shows lower computational time for most of the cases. Overall, this comparative study gives insights into whether denoising will be adopted in various CNN-based image analyses, including autonomous driving, animal detection, and facial recognition.
- Authors: Kaur, Roopdeep , Karmakar, Gour , Imran, Muhammad
- Date: 2023
- Type: Text , Journal article
- Relation: Applied sciences Vol. 13, no. 20 (2023), p.
- Full Text:
- Reviewed:
- Description: In digital image processing, filtering noise is an important step for reconstructing a high-quality image for further processing such as object segmentation, object detection, and object recognition. Various image-denoising approaches, including median, Gaussian, and bilateral filters, are available in the literature. Since convolutional neural networks (CNN) are able to directly learn complex patterns and features from data, they have become a popular choice for image-denoising tasks. As a result of their ability to learn and adapt to various denoising scenarios, CNNs are powerful tools for image denoising. Some deep learning techniques such as CNN incorporate denoising strategies directly into the CNN model layers. A primary limitation of these methods is their necessity to resize images to a consistent size. This resizing can result in a loss of vital image details, which might compromise CNN’s effectiveness. Because of this issue, we utilize a traditional denoising method as a preliminary step for noise reduction before applying CNN. To our knowledge, a comparative performance study of CNN using traditional and embedded denoising against a baseline approach (without denoising) is yet to be performed. To analyze the impact of denoising on the CNN performance, in this paper, firstly, we filter the noise from the images using traditional means of denoising method before their use in the CNN model. Secondly, we embed a denoising layer in the CNN model. To validate the performance of image denoising, we performed extensive experiments for both traffic sign and object recognition datasets. To decide whether denoising will be adopted and to decide on the type of filter to be used, we also present an approach exploiting the peak-signal-to-noise-ratio (PSNRs) distribution of images. Both CNN accuracy and PSNRs distribution are used to evaluate the effectiveness of the denoising approaches. As expected, the results vary with the type of filter, impact, and dataset used in both traditional and embedded denoising approaches. However, traditional denoising shows better accuracy, while embedded denoising shows lower computational time for most of the cases. Overall, this comparative study gives insights into whether denoising will be adopted in various CNN-based image analyses, including autonomous driving, animal detection, and facial recognition.
- Keene, Annabelle, Johnston, Scott, Bush, Richard, Burton, Edward, Sullivan, Leigh
- Authors: Keene, Annabelle , Johnston, Scott , Bush, Richard , Burton, Edward , Sullivan, Leigh
- Date: 2010
- Type: Text , Journal article
- Relation: Marine Pollution Bulletin Vol. 60, no. 4 (2010), p. 620-626
- Full Text: false
- Reviewed:
- Description: This study examines the abundance of trace elements in surface sediments of a former acid sulfate soil (ASS) wetland subjected to marine tidal inundation. Sediment properties of this highly modified study site are compared with those of an adjacent unmodified, intertidal mangrove forest. Whilst some trace elements (Al, Cd, Mn, Ni and Zn) were clearly depleted due to mobilisation and leaching in the previous oxic-acidic phase, other trace elements (As and Cr) displayed significant enrichment in the tidally inundated ASS. Many trace elements were strongly associated with the reactive Fe and acid volatile sulfide (AVS) fractions, suggesting that trace elements may be adsorbed to abundant reactive Fe phases or sequestered as sulfide minerals. These findings provide an important understanding of the fate and mobility of reactive iron, AVS and trace elements during tidal remediation of a formerly acidified Great Barrier Reef (GBR) catchment. © 2010 Elsevier Ltd.
Designing multi-agent system organisations for flexible runtime behaviour
- Keogh, Kathleen, Sonenberg, Liz
- Authors: Keogh, Kathleen , Sonenberg, Liz
- Date: 2020
- Type: Text , Journal article
- Relation: Applied Sciences (Switzerland) Vol. 10, no. 15 (2020), p.
- Full Text:
- Reviewed:
- Description: We address the challenge of multi-agent system (MAS) design for organisations of agents acting in dynamic and uncertain environments where runtime flexibility is required to enable improvisation through sharing knowledge and adapting behaviour. We identify behavioural features that correspond to runtime improvisation by agents in a MAS organisation and from this analysis describe the OJAzzIC meta-model and an associated design method. We present results from simulation scenarios, varying both problem complexity and the level of organisational support provided in the design, to show that increasing design time guidance in the organisation specification can enable runtime flexibility afforded to agents and improve performance. Hence the results demonstrate the usefulness of the constructs captured in the OJAzzIC meta-model. © 2020 by the authors.
- Authors: Keogh, Kathleen , Sonenberg, Liz
- Date: 2020
- Type: Text , Journal article
- Relation: Applied Sciences (Switzerland) Vol. 10, no. 15 (2020), p.
- Full Text:
- Reviewed:
- Description: We address the challenge of multi-agent system (MAS) design for organisations of agents acting in dynamic and uncertain environments where runtime flexibility is required to enable improvisation through sharing knowledge and adapting behaviour. We identify behavioural features that correspond to runtime improvisation by agents in a MAS organisation and from this analysis describe the OJAzzIC meta-model and an associated design method. We present results from simulation scenarios, varying both problem complexity and the level of organisational support provided in the design, to show that increasing design time guidance in the organisation specification can enable runtime flexibility afforded to agents and improve performance. Hence the results demonstrate the usefulness of the constructs captured in the OJAzzIC meta-model. © 2020 by the authors.
Estimation of precipitation fraction in the soil water of the Hillslope Vineyard using stable isotopes of water
- Kovač, Zoran, Krevh, Vedran, Filipović, Lana, Defterdarović, Jasmina, Balaž, Borna-Ivan, Filipović, Vilim
- Authors: Kovač, Zoran , Krevh, Vedran , Filipović, Lana , Defterdarović, Jasmina , Balaž, Borna-Ivan , Filipović, Vilim
- Date: 2023
- Type: Text , Journal article
- Relation: Water (Switzerland) Vol. 15, no. 5 (2023), p.
- Full Text:
- Reviewed:
- Description: This paper presents research related to the estimation of the precipitation fraction in the soil water of a sloped vineyard at the SUPREHILL Critical Zone Observatory (CZO) in Zagreb, Croatia. Numerous investigations have shown that exploration of hillslope soils can be very challenging due to the existence of heterogeneity and different soil properties, as well as due to anthropogenically induced processes, which can affect precipitation infiltration and soil water flow. Within this research, physicochemical soil properties, soil water content (SWC), and isotopic composition of soil water and precipitation (
- Authors: Kovač, Zoran , Krevh, Vedran , Filipović, Lana , Defterdarović, Jasmina , Balaž, Borna-Ivan , Filipović, Vilim
- Date: 2023
- Type: Text , Journal article
- Relation: Water (Switzerland) Vol. 15, no. 5 (2023), p.
- Full Text:
- Reviewed:
- Description: This paper presents research related to the estimation of the precipitation fraction in the soil water of a sloped vineyard at the SUPREHILL Critical Zone Observatory (CZO) in Zagreb, Croatia. Numerous investigations have shown that exploration of hillslope soils can be very challenging due to the existence of heterogeneity and different soil properties, as well as due to anthropogenically induced processes, which can affect precipitation infiltration and soil water flow. Within this research, physicochemical soil properties, soil water content (SWC), and isotopic composition of soil water and precipitation (
- Kraal, Peter, Burton, Edward, Rose, Andrew, Cheetham, Michael, Bush, Richard, Sullivan, Leigh
- Authors: Kraal, Peter , Burton, Edward , Rose, Andrew , Cheetham, Michael , Bush, Richard , Sullivan, Leigh
- Date: 2013
- Type: Text , Journal article
- Relation: Environmental Science and Technology Vol. 47, no. 7 (2013), p. 3114-3121
- Full Text: false
- Reviewed:
- Description: Estuaries are crucial biogeochemical filters at the land-ocean interface that are strongly impacted by anthropogenic nutrient inputs. Here, we investigate benthic nitrogen (N) and phosphorus (P) dynamics in relation to physicochemical surface sediment properties and bottom water mixing in the shallow, eutrophic Peel-Harvey Estuary. Our results show the strong dependence of sedimentary P release on Fe and S redox cycling. The estuary contains surface sediments that are strongly reducing and act as net P source, despite physical sediment mixing under an oxygenated water column. This decoupling between water column oxygenation and benthic P dynamics is of great importance to understand the evolution of nutrient dynamics in marine systems in response to increasing nutrient loadings. In addition, the findings show that the relationship between P burial efficiency and bottom water oxygenation depends on local conditions; sediment properties rather than oxygen availability may control benthic P recycling. Overall, our results illustrate the complex response of an estuary to environmental change because of interacting physical and biogeochemical processes. © 2013 American Chemical Society.
Investigation of hillslope vineyard soil water dynamics using field measurements and numerical modeling
- Krevh, Vedran, Groh, Jannis, Weihermüller, Lutz, Filipović, Lana, Defterdarović, Jasmina, Kovač, Zoran, Magdić, Ivan, Lazarević, Boris, Baumgartl, Thomas, Filipović, Vilim
- Authors: Krevh, Vedran , Groh, Jannis , Weihermüller, Lutz , Filipović, Lana , Defterdarović, Jasmina , Kovač, Zoran , Magdić, Ivan , Lazarević, Boris , Baumgartl, Thomas , Filipović, Vilim
- Date: 2023
- Type: Text , Journal article
- Relation: Water (Switzerland) Vol. 15, no. 4 (2023), p.
- Full Text:
- Reviewed:
- Description: Soil heterogeneities can impact hillslope hydropedological processes (e.g., portioning between infiltration and runoff), creating a need for in-depth knowledge of processes governing water dynamics and redistribution. The presented study was conducted at the SUPREHILL Critical Zone Observatory (CZO) (hillslope vineyard) in 2021. A combination of field investigation (soil sampling and monitoring campaign) and numerical modeling with hydrological simulator HYDRUS-1D was used to explore the water dynamics in conjunction with data from a sensor network (soil water content (SWC) and soil-water potential (SWP) sensors), along the hillslope (hilltop, backslope, and footslope). Soil hydraulic properties (SHP) were estimated based on (i) pedotransfer functions (PTFs), (ii) undisturbed soil cores, and (iii) sensor network data, and tested in HYDRUS. Additionally, a model ensemble mean from HYDRUS simulations was calculated with PTFs. The highest agreement of simulated with observed SWC for 40 cm soil depth was found with the combination of laboratory and field data, with the lowest average MAE, RMSE and MAPE (0.02, 0.02, and 5.34%, respectively), and highest average R2 (0.93), while at 80 cm soil depth, PTF model ensemble performed better (MAE = 0.03, RMSE = 0.03, MAPE = 7.55%, R2 = 0.81) than other datasets. Field observations indicated that heterogeneity and spatial variability regarding soil parameters were present at the site. Over the hillslope, SWC acted in a heterogeneous manner, which was most pronounced during soil rewetting. Model results suggested that the incorporation of field data expands model performance and that the PTF model ensemble is a feasible option in the absence of laboratory data. © 2023 by the authors.
- Authors: Krevh, Vedran , Groh, Jannis , Weihermüller, Lutz , Filipović, Lana , Defterdarović, Jasmina , Kovač, Zoran , Magdić, Ivan , Lazarević, Boris , Baumgartl, Thomas , Filipović, Vilim
- Date: 2023
- Type: Text , Journal article
- Relation: Water (Switzerland) Vol. 15, no. 4 (2023), p.
- Full Text:
- Reviewed:
- Description: Soil heterogeneities can impact hillslope hydropedological processes (e.g., portioning between infiltration and runoff), creating a need for in-depth knowledge of processes governing water dynamics and redistribution. The presented study was conducted at the SUPREHILL Critical Zone Observatory (CZO) (hillslope vineyard) in 2021. A combination of field investigation (soil sampling and monitoring campaign) and numerical modeling with hydrological simulator HYDRUS-1D was used to explore the water dynamics in conjunction with data from a sensor network (soil water content (SWC) and soil-water potential (SWP) sensors), along the hillslope (hilltop, backslope, and footslope). Soil hydraulic properties (SHP) were estimated based on (i) pedotransfer functions (PTFs), (ii) undisturbed soil cores, and (iii) sensor network data, and tested in HYDRUS. Additionally, a model ensemble mean from HYDRUS simulations was calculated with PTFs. The highest agreement of simulated with observed SWC for 40 cm soil depth was found with the combination of laboratory and field data, with the lowest average MAE, RMSE and MAPE (0.02, 0.02, and 5.34%, respectively), and highest average R2 (0.93), while at 80 cm soil depth, PTF model ensemble performed better (MAE = 0.03, RMSE = 0.03, MAPE = 7.55%, R2 = 0.81) than other datasets. Field observations indicated that heterogeneity and spatial variability regarding soil parameters were present at the site. Over the hillslope, SWC acted in a heterogeneous manner, which was most pronounced during soil rewetting. Model results suggested that the incorporation of field data expands model performance and that the PTF model ensemble is a feasible option in the absence of laboratory data. © 2023 by the authors.
Soil–water dynamics investigation at agricultural hillslope with high-precision weighing lysimeters and soil–water collection systems
- Krevh, Vedran, Groh, Jannis, Filipović, Lana, Gerke, Horst, Defterdarović, Jasmina, Thompson, Sally, Sraka, Mario, Bogunović, Igor, Kovač, Zoran, Robinson, Nathan, Baumgartl, Thomas, Filipović, Vilim
- Authors: Krevh, Vedran , Groh, Jannis , Filipović, Lana , Gerke, Horst , Defterdarović, Jasmina , Thompson, Sally , Sraka, Mario , Bogunović, Igor , Kovač, Zoran , Robinson, Nathan , Baumgartl, Thomas , Filipović, Vilim
- Date: 2023
- Type: Text , Journal article
- Relation: Water (Switzerland) Vol. 15, no. 13 (2023), p.
- Full Text:
- Reviewed:
- Description: A quantitative understanding of actual evapotranspiration (ETa) and soil–water dynamics in a hillslope agroecosystem is vital for sustainable water resource management and soil conservation; however, the complexity of processes and conditions involving lateral subsurface flow (LSF) can be a limiting factor in the full comprehension of hillslope soil–water dynamics. The research was carried out at SUPREHILL CZO located on a hillslope agroecosystem (vineyard) over a period of two years (2021–2022) by combining soil characterization and field hydrological measurements, including weighing lysimeters, sensor measurements, and LSF collection system measurements. Lysimeters were placed on the hilltop and the footslope, both having a dynamic controlled bottom boundary, which corresponded to field pressure head measurements, to mimic field soil–water dynamics. Water balance components between the two positions on the slope were compared with the goal of identifying differences that might reveal hydrologically driven differences due to LSF paths across the hillslope. The usually considered limitations of these lysimeters, or the borders preventing LSF through the domain, acted as an aid within this installation setup, as the lack of LSF was compensated for through the pumping system at the footslope. The findings from lysimeters were compared with LSF collection system measurements. Weighing lysimeter data indicated that LSF controlled ETa rates. The results suggest that the onset of LSF contributes to the spatial crop productivity distribution in hillslopes. The present approach may be useful for investigating the impact of LSF on water balance components for similar hillslope sites and crops or other soil surface covers. © 2023 by the authors.
- Authors: Krevh, Vedran , Groh, Jannis , Filipović, Lana , Gerke, Horst , Defterdarović, Jasmina , Thompson, Sally , Sraka, Mario , Bogunović, Igor , Kovač, Zoran , Robinson, Nathan , Baumgartl, Thomas , Filipović, Vilim
- Date: 2023
- Type: Text , Journal article
- Relation: Water (Switzerland) Vol. 15, no. 13 (2023), p.
- Full Text:
- Reviewed:
- Description: A quantitative understanding of actual evapotranspiration (ETa) and soil–water dynamics in a hillslope agroecosystem is vital for sustainable water resource management and soil conservation; however, the complexity of processes and conditions involving lateral subsurface flow (LSF) can be a limiting factor in the full comprehension of hillslope soil–water dynamics. The research was carried out at SUPREHILL CZO located on a hillslope agroecosystem (vineyard) over a period of two years (2021–2022) by combining soil characterization and field hydrological measurements, including weighing lysimeters, sensor measurements, and LSF collection system measurements. Lysimeters were placed on the hilltop and the footslope, both having a dynamic controlled bottom boundary, which corresponded to field pressure head measurements, to mimic field soil–water dynamics. Water balance components between the two positions on the slope were compared with the goal of identifying differences that might reveal hydrologically driven differences due to LSF paths across the hillslope. The usually considered limitations of these lysimeters, or the borders preventing LSF through the domain, acted as an aid within this installation setup, as the lack of LSF was compensated for through the pumping system at the footslope. The findings from lysimeters were compared with LSF collection system measurements. Weighing lysimeter data indicated that LSF controlled ETa rates. The results suggest that the onset of LSF contributes to the spatial crop productivity distribution in hillslopes. The present approach may be useful for investigating the impact of LSF on water balance components for similar hillslope sites and crops or other soil surface covers. © 2023 by the authors.
Kallistatin limits abdominal aortic aneurysm by attenuating generation of reactive oxygen species and apoptosis
- Krishna, Smriti, Li, Jiaze, Wang, Yutang, Moran, Corey, Trollope, Alexandra
- Authors: Krishna, Smriti , Li, Jiaze , Wang, Yutang , Moran, Corey , Trollope, Alexandra
- Date: 2021
- Type: Text , Journal article
- Relation: Scientific Reports Vol. 11, no. 1 (2021), p.
- Full Text:
- Reviewed:
- Description: Inflammation, vascular smooth muscle cell apoptosis and oxidative stress are believed to play important roles in abdominal aortic aneurysm (AAA) pathogenesis. Human kallistatin (KAL; gene SERPINA4) is a serine proteinase inhibitor previously shown to inhibit inflammation, apoptosis and oxidative stress. The aim of this study was to investigate the role of KAL in AAA through studies in experimental mouse models and patients. Serum KAL concentration was negatively associated with the diagnosis and growth of human AAA. Transgenic overexpression of the human KAL gene (KS-Tg) or administration of recombinant human KAL (rhKAL) inhibited AAA in the calcium phosphate (CaPO4) and subcutaneous angiotensin II (AngII) infusion mouse models. Upregulation of KAL in both models resulted in reduction in the severity of aortic elastin degradation, reduced markers of oxidative stress and less vascular smooth muscle apoptosis within the aorta. Administration of rhKAL to vascular smooth muscle cells incubated in the presence of AngII or in human AAA thrombus-conditioned media reduced apoptosis and downregulated markers of oxidative stress. These effects of KAL were associated with upregulation of Sirtuin 1 activity within the aortas of both KS-Tg mice and rodents receiving rhKAL. These results suggest KAL-Sirtuin 1 signalling limits aortic wall remodelling and aneurysm development through reductions in oxidative stress and vascular smooth muscle cell apoptosis. Upregulating KAL may be a novel therapeutic strategy for AAA. © 2021, The Author(s).
- Authors: Krishna, Smriti , Li, Jiaze , Wang, Yutang , Moran, Corey , Trollope, Alexandra
- Date: 2021
- Type: Text , Journal article
- Relation: Scientific Reports Vol. 11, no. 1 (2021), p.
- Full Text:
- Reviewed:
- Description: Inflammation, vascular smooth muscle cell apoptosis and oxidative stress are believed to play important roles in abdominal aortic aneurysm (AAA) pathogenesis. Human kallistatin (KAL; gene SERPINA4) is a serine proteinase inhibitor previously shown to inhibit inflammation, apoptosis and oxidative stress. The aim of this study was to investigate the role of KAL in AAA through studies in experimental mouse models and patients. Serum KAL concentration was negatively associated with the diagnosis and growth of human AAA. Transgenic overexpression of the human KAL gene (KS-Tg) or administration of recombinant human KAL (rhKAL) inhibited AAA in the calcium phosphate (CaPO4) and subcutaneous angiotensin II (AngII) infusion mouse models. Upregulation of KAL in both models resulted in reduction in the severity of aortic elastin degradation, reduced markers of oxidative stress and less vascular smooth muscle apoptosis within the aorta. Administration of rhKAL to vascular smooth muscle cells incubated in the presence of AngII or in human AAA thrombus-conditioned media reduced apoptosis and downregulated markers of oxidative stress. These effects of KAL were associated with upregulation of Sirtuin 1 activity within the aortas of both KS-Tg mice and rodents receiving rhKAL. These results suggest KAL-Sirtuin 1 signalling limits aortic wall remodelling and aneurysm development through reductions in oxidative stress and vascular smooth muscle cell apoptosis. Upregulating KAL may be a novel therapeutic strategy for AAA. © 2021, The Author(s).
Coupling of cellular processes and their coordinated oscillations under continuous light in Cyanothece sp. ATCC 51142, a diazotrophic unicellular cyanobacterium
- Krishnakumar, Sujatha, Gaudana, Sandeep, Vinh, Nguyen, Viswanathan, Ganesh, Chetty, Madhu, Wangikar, Pramod
- Authors: Krishnakumar, Sujatha , Gaudana, Sandeep , Vinh, Nguyen , Viswanathan, Ganesh , Chetty, Madhu , Wangikar, Pramod
- Date: 2015
- Type: Text , Journal article
- Relation: PLoS ONE Vol. 10, no. 5 (2015), p. 1-23
- Full Text:
- Reviewed:
- Description: Unicellular diazotrophic cyanobacteria such as Cyanothece sp. ATCC 51142 (henceforth Cyanothece), temporally separate the oxygen sensitive nitrogen fixation from oxygen evolving photosynthesis not only under diurnal cycles (LD) but also in continuous light (LL). However, recent reports demonstrate that the oscillations in LL occur with a shorter cycle time of ∼11 h. We find that indeed, majority of the genes oscillate in LL with this cycle time. Genes that are upregulated at a particular time of day under diurnal cycle also get upregulated at an equivalent metabolic phase under LL suggesting tight coupling of various cellular events with each other and with the cell's metabolic status. A number of metabolic processes get upregulated in a coordinated fashion during the respiratory phase under LL including glycogen degradation, glycolysis, oxidative pentose phosphate pathway, and tricarboxylic acid cycle. These precede nitrogen fixation apparently to ensure sufficient energy and anoxic environment needed for the nitrogenase enzyme. Photosynthetic phase sees upregulation of photosystem II, carbonate transport, carbon concentrating mechanism, RuBisCO, glycogen synthesis and light harvesting antenna pigment biosynthesis. In Synechococcus elongates PCC 7942, a non-nitrogen fixing cyanobacteria, expression of a relatively smaller fraction of genes oscillates under LL condition with the major periodicity being 24 h. In contrast, the entire cellular machinery of Cyanothece orchestrates coordinated oscillation in anticipation of the ensuing metabolic phase in both LD and LL. These results may have important implications in understanding the timing of various cellular events and in engineering cyanobacteria for biofuel production. © 2015 Krishnakumar et al.
- Authors: Krishnakumar, Sujatha , Gaudana, Sandeep , Vinh, Nguyen , Viswanathan, Ganesh , Chetty, Madhu , Wangikar, Pramod
- Date: 2015
- Type: Text , Journal article
- Relation: PLoS ONE Vol. 10, no. 5 (2015), p. 1-23
- Full Text:
- Reviewed:
- Description: Unicellular diazotrophic cyanobacteria such as Cyanothece sp. ATCC 51142 (henceforth Cyanothece), temporally separate the oxygen sensitive nitrogen fixation from oxygen evolving photosynthesis not only under diurnal cycles (LD) but also in continuous light (LL). However, recent reports demonstrate that the oscillations in LL occur with a shorter cycle time of ∼11 h. We find that indeed, majority of the genes oscillate in LL with this cycle time. Genes that are upregulated at a particular time of day under diurnal cycle also get upregulated at an equivalent metabolic phase under LL suggesting tight coupling of various cellular events with each other and with the cell's metabolic status. A number of metabolic processes get upregulated in a coordinated fashion during the respiratory phase under LL including glycogen degradation, glycolysis, oxidative pentose phosphate pathway, and tricarboxylic acid cycle. These precede nitrogen fixation apparently to ensure sufficient energy and anoxic environment needed for the nitrogenase enzyme. Photosynthetic phase sees upregulation of photosystem II, carbonate transport, carbon concentrating mechanism, RuBisCO, glycogen synthesis and light harvesting antenna pigment biosynthesis. In Synechococcus elongates PCC 7942, a non-nitrogen fixing cyanobacteria, expression of a relatively smaller fraction of genes oscillates under LL condition with the major periodicity being 24 h. In contrast, the entire cellular machinery of Cyanothece orchestrates coordinated oscillation in anticipation of the ensuing metabolic phase in both LD and LL. These results may have important implications in understanding the timing of various cellular events and in engineering cyanobacteria for biofuel production. © 2015 Krishnakumar et al.
- Krishnakumar, Sujatha, Gaudana, Sandeep, Digmurti, Madhuri, Viswanathan, Ganesh, Chetty, Madhu, Wangikar, Pramod
- Authors: Krishnakumar, Sujatha , Gaudana, Sandeep , Digmurti, Madhuri , Viswanathan, Ganesh , Chetty, Madhu , Wangikar, Pramod
- Date: 2015
- Type: Text , Journal article
- Relation: Bioresource Technology Vol. 188, no. (2015), p. 145-152
- Full Text: false
- Reviewed:
- Description: This study investigates the influence of mixotrophy on physiology and metabolism by analysis of global gene expression in unicellular diazotrophic cyanobacterium Cyanothece sp. ATCC 51142 ( henceforth Cyanothece 51142). It was found that Cyanothece 51142 continues to oscillate between photosynthesis and respiration in continuous light under mixotrophy with cycle time of similar to 13 h. Mixotrophy is marked by an extended respiratory phase compared with photoautotrophy. It can be argued that glycerol provides supplementary energy for nitrogen fixation, which is derived primarily from the glycogen reserves during photoautotrophy. The genes of NDH complex, cytochrome c oxidase and ATP synthase are significantly overexpressed in mixotrophy during the day compared to autotrophy with synchronous expression of the bidirectional hydrogenase genes possibly to maintain redox balance. However, nitrogenase complex remains exclusive to nighttime metabolism concomitantly with uptake hydrogenase. This study throws light on interrelations between metabolic pathways with implications in design of hydrogen producer strains. (C) 2015 Elsevier Ltd. All rights reserved.