title: Development of extrudable hydrogels based on carboxymethyl cellulose–gelatin complex coacervates

authors: Gharanjig, Hamid

subjects: hydrogel

abstract: This study investigates the 3D extrusion printing of a carboxymethyl cellulose (CMC)–gelatin complex coacervate system. Various CMC–gelatin coacervate hydrogels were prepared and analyzed to achieve this goal. The impact of the CMC–gelatin ratio, pH, and total biopolymer concentration on coacervation formation and rheological properties was evaluated to characterize the printability of the samples. Turbidity results indicated that the molecular interactions between gelatin and CMC biopolymers are significantly pH-dependent, occurring within the range of pH 3.7 to pH 5.6 for the tested compositions. Confocal Laser Scanning Microscopy (CLSM) confirmed the presence of coacervates as spherical particles within the optimal coacervation range. Scanning electron microscopy micrographs supported the CLSM findings, revealing greater porosity within this optimal pH range. Rheological characterization demonstrated that all CMC–gelatin hydrogels exhibited pseudoplastic behavior, with an inverse correlation between increased coacervation and decreased shear viscosity. Additionally, the coacervates displayed lower tackiness compared to gelatin hydrogels, with the maximum tackiness normal force for various CMC–gelatin ratios ranging from 1 to 15 N, notably lower than the 29 N observed for gelatin hydrogels. Mixtures with CMC–gelatin ratios of 1:15 and 1:20 exhibited the best shear recovery behavior, maintaining higher strength after shear load. The maximum strength of the CMC–gelatin coacervate system was found at a biopolymer concentration of 6%. However, lower biopolymer content allowed for consistent extrusion. Importantly, all tested samples were successfully extruded at 22 ± 2 °C, with the 1:15 biopolymer ratio yielding the most consistent printed quality. Our research highlights the promise of the CMC–gelatin coacervate system for 3D printing applications, particularly in areas that demand precise material deposition and adjustable properties.

text: Development of extrudable hydrogels based on carboxymethyl cellulose–gelatin complex coacervates This study investigates the 3D extrusion printing of a carboxymethyl cellulose (CMC)–gelatin complex coacervate system. Various CMC–gelatin coacervate hydrogels were prepared and analyzed to achieve this goal. The impact of the CMC–gelatin ratio, pH, and total biopolymer concentration on coacervation formation and rheological properties was evaluated to characterize the printability of the samples. Turbidity results indicated that the molecular interactions between gelatin and CMC biopolymers are significantly pH-dependent, occurring within the range of pH 3.7 to pH 5.6 for the tested compositions. Confocal Laser Scanning Microscopy (CLSM) confirmed the presence of coacervates as spherical particles within the optimal coacervation range. Scanning electron microscopy micrographs supported the CLSM findings, revealing greater porosity within this optimal pH range. Rheological characterization demonstrated that all CMC–gelatin hydrogels exhibited pseudoplastic behavior, with an inverse correlation between increased coacervation and decreased shear viscosity. Additionally, the coacervates displayed lower tackiness compared to gelatin hydrogels, with the maximum tackiness normal force for various CMC–gelatin ratios ranging from 1 to 15 N, notably lower than the 29 N observed for gelatin hydrogels. Mixtures with CMC–gelatin ratios of 1:15 and 1:20 exhibited the best shear recovery behavior, maintaining higher strength after shear load. The maximum strength of the CMC–gelatin coacervate system was found at a biopolymer concentration of 6%. However, lower biopolymer content allowed for consistent extrusion. Importantly, all tested samples were successfully extruded at 22 ± 2 °C, with the 1:15 biopolymer ratio yielding the most consistent printed quality. Our research highlights the promise of the CMC–gelatin coacervate system for 3D printing applications, particularly in areas that demand precise material deposition and adjustable properties.

year: 2025-01-08

title: Cloning of the IL-1β3 gene and IL-1β4 pseudogene in salmonids uncovers a second type of IL-1β gene in teleost fish

authors: Husain, Mansourah

subjects: Atlantic salmon

abstract: To date two closely related interleukin-1β genes (IL-1β1 and IL-β2) have been found in salmonids. The cloning of trout and salmon IL-1β3., and a salmon IL-1β4 pseudogene reveals that two types of IL-1β genes exist in teleost species. Type I teleost IL-1β genes, including salmonid IL-1β3, share a similar 6 coding exon structure as in tetrapods. Type II teleost IL-1β genes, e.g. salmonid IL-1β1-2, lack one or two coding exons at their 5'-end, and share higher identities within this subgroup than within the type I subgroup. Both types of IL-1β genes have been found in species of Salmoniformes, Perciformes and Beloniformes, suggesting the divergence occurred early in teleost evolution. Trout IL-1β3 is highly expressed in ovary suggesting a role in reproduction. A relatively high constitutive expression in gills, spleen and kidney and the up-regulation by PAMPs, proinflammatory cytokines and viral infection suggests IL-1β3 also has a role in inflammation and host defence.

text: Cloning of the IL-1β3 gene and IL-1β4 pseudogene in salmonids uncovers a second type of IL-1β gene in teleost fish To date two closely related interleukin-1β genes (IL-1β1 and IL-β2) have been found in salmonids. The cloning of trout and salmon IL-1β3., and a salmon IL-1β4 pseudogene reveals that two types of IL-1β genes exist in teleost species. Type I teleost IL-1β genes, including salmonid IL-1β3, share a similar 6 coding exon structure as in tetrapods. Type II teleost IL-1β genes, e.g. salmonid IL-1β1-2, lack one or two coding exons at their 5'-end, and share higher identities within this subgroup than within the type I subgroup. Both types of IL-1β genes have been found in species of Salmoniformes, Perciformes and Beloniformes, suggesting the divergence occurred early in teleost evolution. Trout IL-1β3 is highly expressed in ovary suggesting a role in reproduction. A relatively high constitutive expression in gills, spleen and kidney and the up-regulation by PAMPs, proinflammatory cytokines and viral infection suggests IL-1β3 also has a role in inflammation and host defence.

year: 2012

title: Defining indigenous trade: A working paper incorporating Māori and indigenous perspectives

authors: McLellan, Georgia

abstract: This working paper is part of a New Zealand Government–funded research project titled ‘Tauhokohoko: Enabling mana motuhake through Indigenous trade’ (Tauhokohoko), which was developed by the University of Waikato and Te Rōpū Taumata Charitable Trust (Te Taumata). The paper was prepared by the Tauhokohoko Research Aim 1.3 team and sets out a working definition of ‘Indigenous trade’.

The Tauhokohoko Research Aim 1.3 team acknowledges that the term ‘Indigenous’ can be problematic, since it collectivises the experiences of all Indigenous peoples. The project acknowledges the diverse realities of Indigenous peoples and strives to use the term in an inclusive way. Despite the existence of fraught relations between Indigenous peoples and postcolonial trade practices, Indigenous peoples have always had their own trade practices and relations grounded in Indigenous ways of being, knowing and doing. Within contemporary economies, Indigenous peoples are increasingly turning to international trade to meet their economic, social and cultural aspirations.

The Tauhokohoko Research Aim 1.3 team believes that Indigenous trade, when practiced in the right way, can be used as a tool for enhancing Indigenous self-determination and collective wellbeing. This paper outlines a tentative definition of ‘Indigenous trade’ for research purposes and provides grounded examples of Indigenous trade that fit within that tentative definition. The Tauhokohoko project is concerned primarily with the involvement of Indigenous peoples in international trade as a financial activity; however, the tentative definition encompasses financial, non financial, tangible and non-tangible forms of exchange. The paper ends by outlining the key literature that informs the working definition of ‘Indigenous trade’, including perspectives on the origins of international trade and Indigenous trade, international business and entrepreneurship, and Indigenous economies.

text: Defining indigenous trade: A working paper incorporating Māori and indigenous perspectives This working paper is part of a New Zealand Government–funded research project titled ‘Tauhokohoko: Enabling mana motuhake through Indigenous trade’ (Tauhokohoko), which was developed by the University of Waikato and Te Rōpū Taumata Charitable Trust (Te Taumata). The paper was prepared by the Tauhokohoko Research Aim 1.3 team and sets out a working definition of ‘Indigenous trade’.

The Tauhokohoko Research Aim 1.3 team acknowledges that the term ‘Indigenous’ can be problematic, since it collectivises the experiences of all Indigenous peoples. The project acknowledges the diverse realities of Indigenous peoples and strives to use the term in an inclusive way. Despite the existence of fraught relations between Indigenous peoples and postcolonial trade practices, Indigenous peoples have always had their own trade practices and relations grounded in Indigenous ways of being, knowing and doing. Within contemporary economies, Indigenous peoples are increasingly turning to international trade to meet their economic, social and cultural aspirations.

The Tauhokohoko Research Aim 1.3 team believes that Indigenous trade, when practiced in the right way, can be used as a tool for enhancing Indigenous self-determination and collective wellbeing. This paper outlines a tentative definition of ‘Indigenous trade’ for research purposes and provides grounded examples of Indigenous trade that fit within that tentative definition. The Tauhokohoko project is concerned primarily with the involvement of Indigenous peoples in international trade as a financial activity; however, the tentative definition encompasses financial, non financial, tangible and non-tangible forms of exchange. The paper ends by outlining the key literature that informs the working definition of ‘Indigenous trade’, including perspectives on the origins of international trade and Indigenous trade, international business and entrepreneurship, and Indigenous economies.

year: 2025-12-10