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Ajay B Patil - One of the best experts on this subject based on the ideXlab platform.
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efficient solvent system containing malonamides in room temperature ionic liquids actinide extraction fluorescence and radiolytic degradation studies
Dalton Transactions, 2013Co-Authors: Ajay B Patil, P N Pathak, Vaishali S Shinde, Shripad V. Godbole, P K MohapatraAbstract:Solvent extraction studies of actinide metal ions such as Am(III), U(VI), Np(IV), Np(VI), Pu(IV) were carried out in a nitric acid medium using two Diamides (L) viz. (DMDBTDMA (N,N′-dimethyl-N,N′-dibutyl-2-tetradecylmalonamide) and DMDOHEMA (N,N′-dimethyl-N,N′-dioctyl-2-(2′-(hexyloxy)ethyl)-malonamide) dissolved in different room temperature ionic liquids (RTILs). The use of RTILs as the diluent significantly enhanced metal ion extraction as compared to that observed in non polar diluent such as n-dodecane. The effects of parameters such as kinetics, aqueous phase acidity (0.01–3 M HNO3), metal ion oxidation states, Diamide concentration on the extraction of metal ions were studied. The stoichiometry of the extracted Am(III) species using these Diamides varied with ligand concentration viz. (Am.3L)3+ ([L] = 0.005–0.02 M) and (Am.2–2.5L)3+ ([L] = 0.05–0.1 M). Time resolved laser induced fluorescence spectroscopy (TRLFS) studies showed that the extracted species of Eu(III) in an ionic liquid medium had no coordinated water molecules, in contrast to the presence of 1–2 water molecules in the extracted species in a n-dodecane medium. The radiolytic degradation behavior of the Diamides/RTIL system has been studied using IR spectroscopy and gas chromatography-mass spectrometry (GC-MS). The data revealed that a significantly lower ligand concentration is required for actinide extraction in ionic liquids as the extraction media as compared to nonpolar diluents.
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efficient solvent system containing malonamides in room temperature ionic liquids actinide extraction fluorescence and radiolytic degradation studies
Dalton Transactions, 2013Co-Authors: Ajay B Patil, P N Pathak, Vaishali S Shinde, Shripad V. Godbole, P K MohapatraAbstract:Solvent extraction studies of actinide metal ions such as Am(III), U(VI), Np(IV), Np(VI), Pu(IV) were carried out in a nitric acid medium using two Diamides (L) viz. (DMDBTDMA (N,N′-dimethyl-N,N′-dibutyl-2-tetradecylmalonamide) and DMDOHEMA (N,N′-dimethyl-N,N′-dioctyl-2-(2′-(hexyloxy)ethyl)-malonamide) dissolved in different room temperature ionic liquids (RTILs). The use of RTILs as the diluent significantly enhanced metal ion extraction as compared to that observed in non polar diluent such as n-dodecane. The effects of parameters such as kinetics, aqueous phase acidity (0.01–3 M HNO3), metal ion oxidation states, Diamide concentration on the extraction of metal ions were studied. The stoichiometry of the extracted Am(III) species using these Diamides varied with ligand concentration viz. (Am.3L)3+ ([L] = 0.005–0.02 M) and (Am.2–2.5L)3+ ([L] = 0.05–0.1 M). Time resolved laser induced fluorescence spectroscopy (TRLFS) studies showed that the extracted species of Eu(III) in an ionic liquid medium had no coordinated water molecules, in contrast to the presence of 1–2 water molecules in the extracted species in a n-dodecane medium. The radiolytic degradation behavior of the Diamides/RTIL system has been studied using IR spectroscopy and gas chromatography-mass spectrometry (GC-MS). The data revealed that a significantly lower ligand concentration is required for actinide extraction in ionic liquids as the extraction media as compared to nonpolar diluents.
Ralf Nauen - One of the best experts on this subject based on the ideXlab platform.
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identification of the ryanodine receptor mutation i4743m and its contribution to Diamide insecticide resistance in spodoptera exigua lepidoptera noctuidae
Insect Science, 2020Co-Authors: Yayun Zuo, Ralf Nauen, Xingliang Wang, Yihua YangAbstract:Insect ryanodine receptors (RyRs) are the targets of Diamide insecticides. Two point mutations G4946E and I4790M (numbering according to Plutella xylostella, PxRyR) in the transmembrane domain of the insect RyRs associated with Diamide resistance have so far been identified in three lepidopteran pests, P. xylostella, Tuta absoluta and Chilo suppressalis. In this study, we identified one of the known RyR target site resistance mutations (I4790M) in a field-collected population of Spodoptera exigua. The field-collected WF population of S. exigua exhibited 154 fold resistance to chlorantraniliprole when compared with the susceptible WH-S strain. Sequencing the transmembrane domains of S. exigua RyR (SeRyR) revealed that the resistant WF strain was homozygous for the I4743M mutation (corresponding to I4790M in PxRyR), whereas the G4900E allele (corresponding to G4946E of PxRyR) was not detected. The 4743M allele was introgressed into the susceptible WH-S strain by crossing WF with WH-S, followed by three rounds of backcrossing with WH-S. The introgressed strain 4743M was homozygous for the mutant 4743M allele and shared about 94% of its genetic background with that of the recipient WH-S strain. Compared with WH-S, the near-isogenic 4743M strain showed moderate levels of resistance to chlorantraniliprole (21 fold), cyantraniliprole (25 fold) and flubenDiamide (22 fold), suggesting that the I4743M mutation confers medium levels of resistance to all three Diamides. Genetic analysis showed Diamide resistance in the 4743M strain was inherited as an autosomal and recessive trait. Results from this study have direct implications for the design of appropriate resistance monitoring and management practices to sustainably control S. exigua.
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detection of a ryanodine receptor target site mutation in Diamide insecticide resistant fall armyworm spodoptera frugiperda
Pest Management Science, 2020Co-Authors: Debora Boaventura, Anderson Bolzan, Fernando Eo Padovez, Daniela M Okuma, Celso Omoto, Ralf NauenAbstract:BACKGROUND: Fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), a major lepidopteran pest in Latin and North America, has very recently invaded the continents of Africa and Asia. FAW has evolved resistance to different insecticides and transgenic corn expressing Bacillus thuringiensis (Bt) toxins. Here, we investigated the extent and mechanisms of resistance to Diamide insecticides in a Brazilian field-collected FAW strain selected using chlorantraniliprole. RESULTS: Continuous laboratory selection of a field-collected FAW strain with chlorantraniliprole resulted in resistance ratios of 225-fold and > 5400-fold against chlorantraniliprole and flubenDiamide, respectively, when compared with a susceptible strain. Pre-exposure to different synergists known to inhibit detoxification enzymes did not result in significantly increased larval toxicity, suggesting a minor role for metabolic resistance. Sequencing of the FAW ryanodine receptor (RyR) C-terminal domains II to VI revealed a single nucleotide polymorphism, resulting in a I4734M mutation recently said to confer target-site resistance to Diamides in lepidopteran pests. Genotyping by pyrosequencing of field-collected FAW larvae sampled in the 2018 crop season suggests a low resistance allele frequency. Furthermore, we developed a fluorescent polymerase chain reaction (PCR)-based allelic discrimination assay for rapid genotyping of field-collected FAW samples, because Diamides are increasingly used in Bt-/non-Bt corn. CONCLUSIONS: Recently, the identified RyR mutation has been shown to confer field resistance in other lepidopteran pests such as diamondback moth, tomato leafminer and striped rice stem borer. The developed PCR-based allelic discrimination assay will help to monitor the frequency and future spread of Diamide resistance allele in FAW field populations and help to implement appropriate resistance management measures. (c) 2019 Society of Chemical Industry.
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detection of a ryanodine receptor target site mutation in Diamide insecticide resistant fall armyworm spodoptera frugiperda
Pest Management Science, 2020Co-Authors: Debora Boaventura, Anderson Bolzan, Fernando Eo Padovez, Daniela M Okuma, Celso Omoto, Ralf NauenAbstract:Background Fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), a major lepidopteran pest in Latin and North America, has very recently invaded the continents of Africa and Asia. FAW has evolved resistance to different insecticides and transgenic corn expressing Bacillus thuringiensis (Bt) toxins. Here, we investigated the extent and mechanisms of resistance to Diamide insecticides in a Brazilian field-collected FAW strain selected using chlorantraniliprole. Results Continuous laboratory selection of a field-collected FAW strain with chlorantraniliprole resulted in resistance ratios of 225-fold and > 5400-fold against chlorantraniliprole and flubenDiamide, respectively, when compared with a susceptible strain. Pre-exposure to different synergists known to inhibit detoxification enzymes did not result in significantly increased larval toxicity, suggesting a minor role for metabolic resistance. Sequencing of the FAW ryanodine receptor (RyR) C-terminal domains II to VI revealed a single nucleotide polymorphism, resulting in a I4734M mutation recently said to confer target-site resistance to Diamides in lepidopteran pests. Genotyping by pyrosequencing of field-collected FAW larvae sampled in the 2018 crop season suggests a low resistance allele frequency. Furthermore, we developed a fluorescent polymerase chain reaction (PCR)-based allelic discrimination assay for rapid genotyping of field-collected FAW samples, because Diamides are increasingly used in Bt-/non-Bt corn. Conclusions Recently, the identified RyR mutation has been shown to confer field resistance in other lepidopteran pests such as diamondback moth, tomato leafminer and striped rice stem borer. The developed PCR-based allelic discrimination assay will help to monitor the frequency and future spread of Diamide resistance allele in FAW field populations and help to implement appropriate resistance management measures. © 2019 Society of Chemical Industry.
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geographic spread genetics and functional characteristics of ryanodine receptor based target site resistance to Diamide insecticides in diamondback moth plutella xylostella
Insect Biochemistry and Molecular Biology, 2015Co-Authors: Denise Steinbach, Peter Lümmen, Oliver Gutbrod, Svend Matthiesen, Corinna Schorn, Ralf NauenAbstract:Anthranilic Diamides and flubenDiamide belong to a new chemical class of insecticides acting as conformation sensitive activators of the insect ryanodine receptor (RyR). These compounds control a diverse range of different herbivorous insects including diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae), a notorious global pest on cruciferous crops, which recently developed resistance due to target-site mutations located in the trans-membrane domain of the Plutella RyR. In the present study we further investigated the genetics and functional implications of a RyR G4946E target-site mutation we recently identified in a Philippine diamondback moth strain (Sudlon). Strain Sudlon is homozygous for the G4946E mutation and has been maintained under laboratory conditions without selection pressure for almost four years, and still exhibit stable resistance ratios of >2000-fold to all commercial Diamides. Its F1 progeny resulting from reciprocal crosses with a susceptible strain (BCS-S) revealed no maternal effects and a Diamide susceptible phenotype, suggesting an autosomally almost recessive mode of inheritance. Subsequent back-crosses indicate a near monogenic nature of the Diamide resistance in strain Sudlon. Radioligand binding studies with Plutella thoracic microsomal membrane preparations provided direct evidence for the dramatic functional implications of the RyR G4946E mutation on both Diamide specific binding and its concentration dependent modulation of [(3)H]ryanodine binding. Computational modelling based on a cryo-EM structure of rabbit RyR1 suggests that Plutella G4946E is located in trans-membrane helix S4 close to S4-S5 linker domain supposed to be involved in the modulation of the voltage sensor, and another recently described mutation, I4790M in helix S2 approx. 13 A opposite of G4946E. Genotyping by pyrosequencing revealed the presence of the RyR G4946E mutation in larvae collected in 2013/14 in regions of ten different countries where Diamide insecticides largely failed to control diamondback moth populations. Thus, our study highlights the global importance of the G4946E RyR target-site mutation, which as a mechanism on its own, confers high-level resistance to Diamide insecticides in diamondback moth.
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Diamide insecticide target site specificity in the Heliothis and Musca ryanodine receptors relative to toxicity.
Journal of Agricultural and Food Chemistry, 2014Co-Authors: Suzhen Qi, Peter Lümmen, Ralf Nauen, John E CasidaAbstract:Anthranilic and phthalic Diamides act on the ryanodine receptor (RyR), which constitutes the Ca2+-activated Ca2+ channel and can be assayed as shown here in Heliothis thoracic muscle tissue with anthranilic Diamide [3H]chlorantraniliprole ([3H]Chlo), phthalic Diamide [3H]flubenDiamide ([3H]Flu), and [3H]ryanodine ([3H]Ry). Using Heliothis with [3H]Chlo or [3H]Flu gives very similar anthranilic and phthalic Diamide binding site structure–activity correlations, indicating a common binding site. The anthranilic and phthalic Diamide stimulation of [3H]Ry binding in Heliothis generally parallels their inhibition of [3H]Chlo and [3H]Flu binding. In Musca adults [3H]Ry binding site stimulation is a good predictor of in vivo activity for anthranilic but not phthalic Diamides, and no high-affinity [3H]Flu specific binding site is observed. These relationships establish species differences in Diamide target site specificity important in structure optimization and target site-based resistance mechanisms.
P K Mohapatra - One of the best experts on this subject based on the ideXlab platform.
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efficient solvent system containing malonamides in room temperature ionic liquids actinide extraction fluorescence and radiolytic degradation studies
Dalton Transactions, 2013Co-Authors: Ajay B Patil, P N Pathak, Vaishali S Shinde, Shripad V. Godbole, P K MohapatraAbstract:Solvent extraction studies of actinide metal ions such as Am(III), U(VI), Np(IV), Np(VI), Pu(IV) were carried out in a nitric acid medium using two Diamides (L) viz. (DMDBTDMA (N,N′-dimethyl-N,N′-dibutyl-2-tetradecylmalonamide) and DMDOHEMA (N,N′-dimethyl-N,N′-dioctyl-2-(2′-(hexyloxy)ethyl)-malonamide) dissolved in different room temperature ionic liquids (RTILs). The use of RTILs as the diluent significantly enhanced metal ion extraction as compared to that observed in non polar diluent such as n-dodecane. The effects of parameters such as kinetics, aqueous phase acidity (0.01–3 M HNO3), metal ion oxidation states, Diamide concentration on the extraction of metal ions were studied. The stoichiometry of the extracted Am(III) species using these Diamides varied with ligand concentration viz. (Am.3L)3+ ([L] = 0.005–0.02 M) and (Am.2–2.5L)3+ ([L] = 0.05–0.1 M). Time resolved laser induced fluorescence spectroscopy (TRLFS) studies showed that the extracted species of Eu(III) in an ionic liquid medium had no coordinated water molecules, in contrast to the presence of 1–2 water molecules in the extracted species in a n-dodecane medium. The radiolytic degradation behavior of the Diamides/RTIL system has been studied using IR spectroscopy and gas chromatography-mass spectrometry (GC-MS). The data revealed that a significantly lower ligand concentration is required for actinide extraction in ionic liquids as the extraction media as compared to nonpolar diluents.
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efficient solvent system containing malonamides in room temperature ionic liquids actinide extraction fluorescence and radiolytic degradation studies
Dalton Transactions, 2013Co-Authors: Ajay B Patil, P N Pathak, Vaishali S Shinde, Shripad V. Godbole, P K MohapatraAbstract:Solvent extraction studies of actinide metal ions such as Am(III), U(VI), Np(IV), Np(VI), Pu(IV) were carried out in a nitric acid medium using two Diamides (L) viz. (DMDBTDMA (N,N′-dimethyl-N,N′-dibutyl-2-tetradecylmalonamide) and DMDOHEMA (N,N′-dimethyl-N,N′-dioctyl-2-(2′-(hexyloxy)ethyl)-malonamide) dissolved in different room temperature ionic liquids (RTILs). The use of RTILs as the diluent significantly enhanced metal ion extraction as compared to that observed in non polar diluent such as n-dodecane. The effects of parameters such as kinetics, aqueous phase acidity (0.01–3 M HNO3), metal ion oxidation states, Diamide concentration on the extraction of metal ions were studied. The stoichiometry of the extracted Am(III) species using these Diamides varied with ligand concentration viz. (Am.3L)3+ ([L] = 0.005–0.02 M) and (Am.2–2.5L)3+ ([L] = 0.05–0.1 M). Time resolved laser induced fluorescence spectroscopy (TRLFS) studies showed that the extracted species of Eu(III) in an ionic liquid medium had no coordinated water molecules, in contrast to the presence of 1–2 water molecules in the extracted species in a n-dodecane medium. The radiolytic degradation behavior of the Diamides/RTIL system has been studied using IR spectroscopy and gas chromatography-mass spectrometry (GC-MS). The data revealed that a significantly lower ligand concentration is required for actinide extraction in ionic liquids as the extraction media as compared to nonpolar diluents.
Debora Boaventura - One of the best experts on this subject based on the ideXlab platform.
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detection of a ryanodine receptor target site mutation in Diamide insecticide resistant fall armyworm spodoptera frugiperda
Pest Management Science, 2020Co-Authors: Debora Boaventura, Anderson Bolzan, Fernando Eo Padovez, Daniela M Okuma, Celso Omoto, Ralf NauenAbstract:BACKGROUND: Fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), a major lepidopteran pest in Latin and North America, has very recently invaded the continents of Africa and Asia. FAW has evolved resistance to different insecticides and transgenic corn expressing Bacillus thuringiensis (Bt) toxins. Here, we investigated the extent and mechanisms of resistance to Diamide insecticides in a Brazilian field-collected FAW strain selected using chlorantraniliprole. RESULTS: Continuous laboratory selection of a field-collected FAW strain with chlorantraniliprole resulted in resistance ratios of 225-fold and > 5400-fold against chlorantraniliprole and flubenDiamide, respectively, when compared with a susceptible strain. Pre-exposure to different synergists known to inhibit detoxification enzymes did not result in significantly increased larval toxicity, suggesting a minor role for metabolic resistance. Sequencing of the FAW ryanodine receptor (RyR) C-terminal domains II to VI revealed a single nucleotide polymorphism, resulting in a I4734M mutation recently said to confer target-site resistance to Diamides in lepidopteran pests. Genotyping by pyrosequencing of field-collected FAW larvae sampled in the 2018 crop season suggests a low resistance allele frequency. Furthermore, we developed a fluorescent polymerase chain reaction (PCR)-based allelic discrimination assay for rapid genotyping of field-collected FAW samples, because Diamides are increasingly used in Bt-/non-Bt corn. CONCLUSIONS: Recently, the identified RyR mutation has been shown to confer field resistance in other lepidopteran pests such as diamondback moth, tomato leafminer and striped rice stem borer. The developed PCR-based allelic discrimination assay will help to monitor the frequency and future spread of Diamide resistance allele in FAW field populations and help to implement appropriate resistance management measures. (c) 2019 Society of Chemical Industry.
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detection of a ryanodine receptor target site mutation in Diamide insecticide resistant fall armyworm spodoptera frugiperda
Pest Management Science, 2020Co-Authors: Debora Boaventura, Anderson Bolzan, Fernando Eo Padovez, Daniela M Okuma, Celso Omoto, Ralf NauenAbstract:Background Fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), a major lepidopteran pest in Latin and North America, has very recently invaded the continents of Africa and Asia. FAW has evolved resistance to different insecticides and transgenic corn expressing Bacillus thuringiensis (Bt) toxins. Here, we investigated the extent and mechanisms of resistance to Diamide insecticides in a Brazilian field-collected FAW strain selected using chlorantraniliprole. Results Continuous laboratory selection of a field-collected FAW strain with chlorantraniliprole resulted in resistance ratios of 225-fold and > 5400-fold against chlorantraniliprole and flubenDiamide, respectively, when compared with a susceptible strain. Pre-exposure to different synergists known to inhibit detoxification enzymes did not result in significantly increased larval toxicity, suggesting a minor role for metabolic resistance. Sequencing of the FAW ryanodine receptor (RyR) C-terminal domains II to VI revealed a single nucleotide polymorphism, resulting in a I4734M mutation recently said to confer target-site resistance to Diamides in lepidopteran pests. Genotyping by pyrosequencing of field-collected FAW larvae sampled in the 2018 crop season suggests a low resistance allele frequency. Furthermore, we developed a fluorescent polymerase chain reaction (PCR)-based allelic discrimination assay for rapid genotyping of field-collected FAW samples, because Diamides are increasingly used in Bt-/non-Bt corn. Conclusions Recently, the identified RyR mutation has been shown to confer field resistance in other lepidopteran pests such as diamondback moth, tomato leafminer and striped rice stem borer. The developed PCR-based allelic discrimination assay will help to monitor the frequency and future spread of Diamide resistance allele in FAW field populations and help to implement appropriate resistance management measures. © 2019 Society of Chemical Industry.
John M Torkelson - One of the best experts on this subject based on the ideXlab platform.
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Non-Isocyanate Polyurethane Thermoplastic Elastomer: Amide-Based Chain Extender Yields Enhanced Nanophase Separation and Properties in Polyhydroxyurethane
Macromolecules, 2017Co-Authors: Goliath Beniah, William H Heath, David J. Fortman, William R. Dichtel, John M TorkelsonAbstract:Non-isocyanate polyurethane (NIPU) was synthesized via cyclic carbonate aminolysis using poly(ethylene oxide) (PEO)- and poly(tetramethylene oxide) (PTMO)-based soft segments, divinylbenzene dicyclocarbonate as hard segment, and diamine–Diamide (DDA) chain extender. Characterization of the resulting segmented polyhydroxyurethanes (PHUs) reveals that the use of amide-based DDA chain extender leads to unprecedented improvements in nanophase separation and thermal and mechanical properties over segmented PHUs without DDA chain extender. With PEO-based soft segments, previously known to yield only phase-mixed PHUs, use of DDA chain extender yields nanophase-separated PHUs above a certain hard-segment content, as characterized by small-angle X-ray scattering. With PTMO-based soft segments, previously known to yield nanophase-separated PHUs with broad interphase, use of DDA chain extender produces nanophase-separated PHUs with sharp domain interphase, leading to wide, relatively temperature-independent rubbery ...
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Non-Isocyanate Polyurethane Thermoplastic Elastomer: Amide-Based Chain Extender Yields Enhanced Nanophase Separation and Properties in Polyhydroxyurethane
2017Co-Authors: Goliath Beniah, William H Heath, David J. Fortman, William R. Dichtel, John M TorkelsonAbstract:Non-isocyanate polyurethane (NIPU) was synthesized via cyclic carbonate aminolysis using poly(ethylene oxide) (PEO)- and poly(tetramethylene oxide) (PTMO)-based soft segments, divinylbenzene dicyclocarbonate as hard segment, and diamine–Diamide (DDA) chain extender. Characterization of the resulting segmented polyhydroxyurethanes (PHUs) reveals that the use of amide-based DDA chain extender leads to unprecedented improvements in nanophase separation and thermal and mechanical properties over segmented PHUs without DDA chain extender. With PEO-based soft segments, previously known to yield only phase-mixed PHUs, use of DDA chain extender yields nanophase-separated PHUs above a certain hard-segment content, as characterized by small-angle X-ray scattering. With PTMO-based soft segments, previously known to yield nanophase-separated PHUs with broad interphase, use of DDA chain extender produces nanophase-separated PHUs with sharp domain interphase, leading to wide, relatively temperature-independent rubbery plateau regions and much improved thermal properties with flow temperature as high as 200 °C. The PTMO-based PHUs with 19–34 wt % hard-segment content exhibit tunable mechanical properties with Young’s modulus ranging from 6.6 to 43.2 MPa and tensile strength from 2.4 to 6.7 MPa, with ∼300% elongation at break. Cyclic tensile testing shows that these PHUs exhibit elastomeric recovery with attributes very similar to conventional, isocyanate-based thermoplastic polyurethane elastomers