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Patel, Zh.; Khul'ka, K.

doi:10.1023/a:1014897029026

Cited by 11 publications

(5 citation statements)

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“…Complexes of the heavier group five metals, niobium and tantalum, have received little attention as initiators for the ROP of cyclic esters, with only a small handful of reports in the literature. ,– Indeed, the authors are aware of no established industrial catalytic processes mediated by Nb-based species, although this metal does have various specialist metallurgical uses, , as well as having more recently garnered interest in relation to potential energy material applications. – Importantly, ethical sourcing of Nb and Ta is a key consideration in developing any process for which they might be employed. – …”

Section: Introductionmentioning

confidence: 99%

Coordination of ε-Caprolactone to a Cationic Niobium(V) Alkoxide Complex: Fundamental Insight into Ring-Opening Polymerization via Coordination–Insertion

Buchard,

Davidson,

Gobius du Sart

et al. 2023

Inorg. Chem.

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We report three niobium-based initiators for the catalytic ring-opening polymerization (ROP) of ε-caprolactone, exhibiting good activity and molecular weight control. In particular, we have prepared on the gram-scale and fully characterized a monometallic cationic alkoxo-Nb(V) ε-caprolactone adduct representing, to the best of our knowledge, an unprecedented example of a metal complex with an intact lactone monomer and a functional ROP-initiating group simultaneously coordinated at the metal center. At 80 °C, all three systems initiate the immortal solution-state ROP of ε-caprolactone via a coordination−insertion mechanism, which has been confirmed through experimental studies, and is supported by computational data. Natural bond orbital calculations further indicate that polymerization may necessitate isomerization about the metal center between the alkoxide chain and the coordinated monomer. The observations made in this work are expected to inform mechanistic understanding both of amine tris(phenolate)-supported metal alkoxide ROP initiators, including various highly stereoselective systems for the polymerization of lactides and of coordination−insertion-type ROP protocols more broadly.

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Section: Introductionmentioning

confidence: 99%

Coordination of ε-Caprolactone to a Cationic Niobium(V) Alkoxide Complex: Fundamental Insight into Ring-Opening Polymerization via Coordination–Insertion

Buchard,

Davidson,

Gobius du Sart

et al. 2023

Inorg. Chem.

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“…Usually, the microalloyed steels contain small amounts (less than 0.1wt%) of microalloying elements such as niobium, titanium and vanadium [59][60][61]. The addition of these microalloying elements provides better strength and toughness through the refinement of the transformed products and strength through solid solution and/or precipitation strengthening.…”

Section: Microalloying Elementsmentioning

confidence: 99%

Thermomechanical Processing of Structural Steels with Dilute Niobium Additions

Cui¹,

Patel²,

Palmiere³

2015

HSLA Steels 2015, Microalloying 2015 &Amp; Offshore Engineering Steels 2015

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-i - AbstractIn this thesis, the influence of various dilute Nb additions (0.005-0.02 wt%) on austenite microstructure evolution along thermomechanical processing, in terms of austenite recrystallisation and grain growth, were investigated using steels with three carbon content levels.At the homogenisation temperature of 1250°C, all dilute Nb additions were dissolved in low carbon steels whereas the Nb dissolution limits for 0.4 wt% and 0.6 wt% C steels were 0.012 wt% and 0.08 wt%, respectively. Dilute Nb additions did not show significant influence on homogenised austenite grain size. The dramatic increase in C contents was more influential, which decreased the homogenised austenite grain size.The influence of dilute Nb additions and C contents on dynamic recrystallisation behaviour was studied by rough rolling at high deformation temperature with low strain rate. The dilute Nb additions were found to increase the critical strain of dynamic recrystallisation whereas C contents showed no influence on the dynamic recrystallisation behaviour.The austenite recrystallisation behaviour after finish rolling and after the holding period between finishing passes were studied by means of interrupted plane strain compression (PSC) tests and double hit PSC tests. It was found that with low Nb supersaturation, recrystallisation happened prior to Nb precipitation. Solute Nb in austenite delayed the onset of austenite recrystallisation through solute drag effect.With high Nb supersaturation, Nb precipitation occurred before the onset of recrystallisation which completely retarded austenite recrystallisation.The austenite grain growth during the holding period between finish rolling passes was studied by the evolution of prior-austenite grain size before and after the 20s holding period at the highest finish rolling temperature (1050°C). There was no Nb precipitation found and the difference in austenite grain growth behaviour was Abstract -iiattributed to the solute drag effect from both Nb and C in solution. It was found that Nb in solution suppressed austenite grain growth. However, the effectiveness of solute Nb in suppressing austenite grain growth was affected by the C content. Acknowledgement

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“…In the synovial tissue (ST) of affected rheumatoid joints there are abundant macrophages and T lymphocytes expressing CCR5 and CXCR3 (333,470,716). CCL3, CCL4 and CCL5 are present at high levels in the synovial fluid (SF) of affected RA joints (508,662,716). In vitro experiments have shown that inhibiting CCL3 and CCL5 in RA SF using neutralizing antibodies will inhibit chemotaxis of lymphocytes (8,333,555,716).…”

Section: Ccr5: a Potential Therapeutic Targetmentioning

confidence: 99%

The role of CCR5 in vaccinia virus pathogenesis

Rahbar

Fish

2009

Cytokine

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Viral appropriation of chemokine receptors is an effective way to prevent a host immune response against the invading virus. Many viruses, including poxviruses, subvert the host immune response by encoding several chemokine receptor homologues, capable of binding to and thereby precluding chemokines from activating their cognate cell surface receptors. All poxviruses employ strategies to modulate chemokine activity, including virus-encoded chemokine-binding proteins, receptor homologues and ligand mimics. The potential for the involvement of certain chemokine receptors in poxviral infection was suggested in studies utilizing the rabbit poxvirus, myxoma. Specifically, CCR5 was implicated in mediating cell target susceptibility to infection. Our data suggest virus-CCR5 interactions may lead to the selective activation of distinct signaling pathways that are advantageous for the virus.VACV, a member of the poxvirus family, produces two structurally distinct forms of virions, the intracellular mature virus (IMV) and the extracellular enveloped virus (EEV), for which the immediate events following cell entry are illiii defined. Using confocal microscopy, we provided evidence that IMV and EEV enter both permissive and non-permissive cells, and that introduction of CCR5 into non-permissive cells -mouse fibroblasts and human PM1 T cells -renders them permissive for VACV replication. We showed that virus activation of CCR5 leads to the selective activation of distinct signaling pathways that are advantageous for the virus. We demonstrated that VACV infection in permissive cells is inhibited by siRNA knockdown of cell surface

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Cited by 11 publications

References 0 publications

Coordination of ε-Caprolactone to a Cationic Niobium(V) Alkoxide Complex: Fundamental Insight into Ring-Opening Polymerization via Coordination–Insertion

Coordination of ε-Caprolactone to a Cationic Niobium(V) Alkoxide Complex: Fundamental Insight into Ring-Opening Polymerization via Coordination–Insertion

Thermomechanical Processing of Structural Steels with Dilute Niobium Additions

The role of CCR5 in vaccinia virus pathogenesis

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