title: Two complexes containing 19-atom chains linking metal centres

authors: Bruce, Michael I.

subjects: carbon chain

abstract: The first example of a complex containing a C₁₉ chain, {Co₃(μ-dppm)(CO)₇}{μ₃-C(C≡C)₉}{W(CO)₃Cp}, has been prepared in 22% yield from the Pd(0) / Cu(I)-catalysed reaction between I(C≡C)₃I, W{C≡CC≡CAu(PPh₃)}(CO)₃Cp and Co₃{μ₃-C(C≡C)₄Au(PPh₃)}(μ-dppm)(CO)₇. Other products also formed include {Co₃(μ-dppm)(CO)₇}{μ₃-C(C≡C)₆}{W(CO)₃Cp} (32%), {Co₃(μ-dppm)(CO)₇}₂{μ₃:μ₃-C(C≡C)xC} [x = 8 (6%) and 11 (5%)], containing respectively C₁₃, C₁₈ and C₂₄ chains, and {W(CO)₃Cp}₂{μ-(C≡C)x} (x = 4, 7) (traces). A second example of a 19-atom chain is found in Hg{(C≡C)₄C[Co₃(μ-dppm)(CO)₇]}₂, obtained in 24% yield from the reaction between Hg(OAc)₂ and Co₃{μ₃-C(C≡C)₄SiMe₃}(μ-dppm)(CO)₇ in the presence of NaOMe.

text: Two complexes containing 19-atom chains linking metal centres The first example of a complex containing a C₁₉ chain, {Co₃(μ-dppm)(CO)₇}{μ₃-C(C≡C)₉}{W(CO)₃Cp}, has been prepared in 22% yield from the Pd(0) / Cu(I)-catalysed reaction between I(C≡C)₃I, W{C≡CC≡CAu(PPh₃)}(CO)₃Cp and Co₃{μ₃-C(C≡C)₄Au(PPh₃)}(μ-dppm)(CO)₇. Other products also formed include {Co₃(μ-dppm)(CO)₇}{μ₃-C(C≡C)₆}{W(CO)₃Cp} (32%), {Co₃(μ-dppm)(CO)₇}₂{μ₃:μ₃-C(C≡C)xC} [x = 8 (6%) and 11 (5%)], containing respectively C₁₃, C₁₈ and C₂₄ chains, and {W(CO)₃Cp}₂{μ-(C≡C)x} (x = 4, 7) (traces). A second example of a 19-atom chain is found in Hg{(C≡C)₄C[Co₃(μ-dppm)(CO)₇]}₂, obtained in 24% yield from the reaction between Hg(OAc)₂ and Co₃{μ₃-C(C≡C)₄SiMe₃}(μ-dppm)(CO)₇ in the presence of NaOMe.

year: 2009

title: Delivery of a coated bioactive from a rumen controlled-release device

authors: Syzov, Vladyslav

subjects: Eudragit E100

abstract: Ruminants possess a unique digestive system. Using the high metabolic potential of the symbiotic microflora of the rumen, ruminants are capable of digesting plant material and obtaining nutrients and energy from this process. Because of the ruminal fermentation, the most bioactives are not stable in the harsh ruminal environment. Therefore there is a need to improve the bioavailability of a bioactive by protecting it from the ruminal digestion. The formulation of protected bioactive can be delivered in the rumen in a controlled manner and over a long period of time.

In this project the degree of rumen protection was estimated using model substrates (sugar pellets and granules). These materials were coated with the pH-sensitive polymer Eudragit E. The model bioactive (phloridizin) was coated using the coating methodology adopted from exploratory studies with model substrates. The bioavailability of protected (coated) phloridizin was assessed by administering directly into the abomasum of fistulated cows.

Formulation of protected phloridizin was used to demonstrate the feasibility of bioactive controlled delivery based on ART ( Active Rumen Technology ). This technology uses an elevated gas pressure created by a hydrogen-producing cell to drive a plunger which extrudes bioactive formulation from an intraruminal controlled-release device.

Four groups of devices filled with formulation containing different amounts of protected phloridizin were tested. The bioactive was released in a controlled manner over several days. The formulation release profiles were reproducible suggesting that in principle the technology can be further developed to use in a commercial sense or for research purposes. The limitations of the technology, including formulation issues and gas diffusion through barrel walls, were identified.

text: Delivery of a coated bioactive from a rumen controlled-release device Ruminants possess a unique digestive system. Using the high metabolic potential of the symbiotic microflora of the rumen, ruminants are capable of digesting plant material and obtaining nutrients and energy from this process. Because of the ruminal fermentation, the most bioactives are not stable in the harsh ruminal environment. Therefore there is a need to improve the bioavailability of a bioactive by protecting it from the ruminal digestion. The formulation of protected bioactive can be delivered in the rumen in a controlled manner and over a long period of time.

In this project the degree of rumen protection was estimated using model substrates (sugar pellets and granules). These materials were coated with the pH-sensitive polymer Eudragit E. The model bioactive (phloridizin) was coated using the coating methodology adopted from exploratory studies with model substrates. The bioavailability of protected (coated) phloridizin was assessed by administering directly into the abomasum of fistulated cows.

Formulation of protected phloridizin was used to demonstrate the feasibility of bioactive controlled delivery based on ART ( Active Rumen Technology ). This technology uses an elevated gas pressure created by a hydrogen-producing cell to drive a plunger which extrudes bioactive formulation from an intraruminal controlled-release device.

Four groups of devices filled with formulation containing different amounts of protected phloridizin were tested. The bioactive was released in a controlled manner over several days. The formulation release profiles were reproducible suggesting that in principle the technology can be further developed to use in a commercial sense or for research purposes. The limitations of the technology, including formulation issues and gas diffusion through barrel walls, were identified.

year: 2008

title: Indigenous-washing and colonial amnesia: how New Zealand’s nation brand depoliticizes climate change

authors: Hellmann, Olli

abstract: New Zealand’s nation brand has drawn ever louder accusations of “greenwashing” the country’s image in recent years. Through a visual discourse analysis of Air New Zealand’s Tiaki & The Guardians safety briefing video, this article shows that brand managers have responded with a strategy of “Indigenous-washing,” appropriating the Māori worldview to deflect attention from intensive farming’s carbon footprint and other environmentally unfriendly activities. More broadly, this article makes an important contribution to the growing critical-cultural literature on nation branding by revealing how New Zealand’s latest marketing initiative contributes to the depoliticization of climate change. The “Tiaki” campaign not only positions New Zealand as an “untouched land,” but also closes the space for democratic debate about climate change by obscuring the role of colonialism in causing the planet’s ecological crisis and by silencing alternative socioecological futures proposed by Indigenous peoples.

text: Indigenous-washing and colonial amnesia: how New Zealand’s nation brand depoliticizes climate change New Zealand’s nation brand has drawn ever louder accusations of “greenwashing” the country’s image in recent years. Through a visual discourse analysis of Air New Zealand’s Tiaki & The Guardians safety briefing video, this article shows that brand managers have responded with a strategy of “Indigenous-washing,” appropriating the Māori worldview to deflect attention from intensive farming’s carbon footprint and other environmentally unfriendly activities. More broadly, this article makes an important contribution to the growing critical-cultural literature on nation branding by revealing how New Zealand’s latest marketing initiative contributes to the depoliticization of climate change. The “Tiaki” campaign not only positions New Zealand as an “untouched land,” but also closes the space for democratic debate about climate change by obscuring the role of colonialism in causing the planet’s ecological crisis and by silencing alternative socioecological futures proposed by Indigenous peoples.

year: 2023-07-27