31,452 research outputs found
Mutations in multidomain protein MEGF8 identify a Carpenter syndrome subtype associated with defective lateralization
No full textCarpenter syndrome is an autosomal-recessive multiple-congenital-malformation disorder characterized by multisuture craniosynostosis and polysyndactyly of the hands and feet; many other clinical features occur, and the most frequent include obesity, umbilical hernia, cryptorchidism, and congenital heart disease. Mutations of RAB23, encoding a small GTPase that regulates vesicular transport, are present in the majority of cases. Here, we describe a disorder caused by mutations in multiple epidermal-growth-factor-like-domains 8 (MEGF8), which exhibits substantial clinical overlap with Carpenter syndrome but is frequently associated with abnormal left-right patterning. We describe five affected individuals with similar dysmorphic facies, and three of them had either complete situs inversus, dextrocardia, or transposition of the great arteries; similar cardiac abnormalities were previously identified in a mouse mutant for the orthologous Megf8. The mutant alleles comprise one nonsense, three missense, and two splice-site mutations; we demonstrate in zebrafish that, in contrast to the wild-type protein, the proteins containing all three missense alterations provide only weak rescue of an early gastrulation phenotype induced by Megf8 knockdown. We conclude that mutations in MEGF8 cause a Carpenter syndrome subtype frequently associated with defective left-right patterning, probably through perturbation of signaling by hedgehog and nodal family members. We did not observe any subject with biallelic loss-of function mutations, suggesting that some residual MEGF8 function might be necessary for survival and might influence the phenotypes observed
Developments in the hydrogenation of challenging substrates utilising transition metal complexes
No full textThis thesis describes the developments of new protocols for the hydrogenation of challenging substrates. Three specific substrates were highlighted for study after an initial review of the literature; benzofurans, esters and bulky ketones.
Chapter 1 details a review of the hydrogenation of challenging unsaturated substrates, highlighting areas where development is still required.
Chapter 2 describes studies on the hydrogenation of 2,3-benzofuran. While a benzofuran hydrogenation catalysts was optimised, severe conditions were required to facilitate the reaction, and not found to be applicable for more elaborate substrates. We therefore considered an alternative process of enantioselective hydrogenation of benzofuranyl ketones followed by heterogeneous hydrogenation. A good process for transfer hydrogenation of a range of these hitherto unstudied substrates was developed along with greater understanding.
The hydrogenation of esters is another challenge in the catalytic reduction field, so was also selected for study, with the results described in Chapter 3. After screening a range of catalysts of types [RuCl₂ (diphosphine)(diamine)] and [RuCl₂ (PNX)(DMSO)], good catalysts were identified. Successful hydrogenation of a range of esters, under mild conditions was achieved using [RuCl₂ (1,3-bisdiphenylphosphinepropane)(2-aminomethylpyridine)] using high concentrations of base co-catalyst. [RuCl₂ ((2-(diphenylphosphanylbenzyl)ethane-1,2-diamine)(DMSO)] combined with 15-25 mol% of a basic co-catalyst have been shown to be active at near ambient conditions in the hydrogenation of aromatic esters.
Chapter 4 related to studies where the activity of Ru, Ir and Rh complexes of the same tridentate ligand were tested in the hydrogenation of ketones that would be regarded as sluggish substrates. Highly active and selective catalysts for the hydrogenation of bulky acetophenone derivatives were found using iridium complexes of PNX ligands (formed in situ). The highest selectivity was obtained with acetophenone substrates containing iso-propyl and cyclohexyl substituents, or medicinally important piperdinyl groups. In the best cases over 90% e.e. was observed with high conversions and with only 0.1 mol% of catalyst
Mischocyttarus pelor Carpenter, 1988: 89 in Carpenter & Wenzel 1988
No full textMischocyttarus pelor Carpenter, 1988: 89 in Carpenter & Wenzel, 1988 Paratype: 1♀ (# MZSP 56996) ‘ Costa Rica, Turrialba, 31.May.1951, OLCartwright’ ‘ Paratype, Mischocyttarus pelor Carpenter’.Published as part of Andrade, Tamires de O., Ramos, Kelli S., Onody, Helena C., dos Santos, Alvaro D. & Brandão, Carlos Roberto F., 2018, Type specimens of Pompiloidea, Thynnoidea and Vespoidea (Hymenoptera) deposited in the Museu de Zoologia da Universidade de São Paulo, Brazil, pp. 1-21 in Papéis Avulsos de Zoologia 58 on page 17, DOI: 10.11606/1807-0205/2018.58.39, http://zenodo.org/record/461350
Protopolybia bituberculata Silveira & Carpenter 1995
No full textProtopolybia bituberculata Silveira & Carpenter 1995: 48 Paratypes: 3♀ (# MZSP 57089‑57091) ‘ Peru, Depto. [Departament] Loreto, 40 km NE Iquitos, 29 December 1990, Carpenter & Wenzel, Nest 901229‑7’ ‘ Paratype, Protopolybia bituberculata, Silveira & Carpenter’.Published as part of Andrade, Tamires de O., Ramos, Kelli S., Onody, Helena C., dos Santos, Alvaro D. & Brandão, Carlos Roberto F., 2018, Type specimens of Pompiloidea, Thynnoidea and Vespoidea (Hymenoptera) deposited in the Museu de Zoologia da Universidade de São Paulo, Brazil, pp. 1-21 in Papéis Avulsos de Zoologia 58 on page 12, DOI: 10.11606/1807-0205/2018.58.39, http://zenodo.org/record/461350
Metapolybia miltoni Andena & Carpenter 2011
No full textMetapolybia miltoni Andena & Carpenter 2011: 117 (http://hol.osu.edu/spmInfo.html?id=MZSP%2056896) Holotype: ♀ (# MZSP 56896) ‘ Brasil, S.[ão] P.[aulo], Ribeirão Preto, 21°09’S, 47°51’W, 860 m, 15 may 1997, James M. Carpenter Nest, 970515‑9’‘ Metapolybia miltoni, Antena & Carpenter’. Paratypes: 1♀ (# MZSP 56897) ‘ Brasil, S.[ão] P.[aulo], Ribeirão Preto, 21°09’S, 47°51’W, 860 m, 15 may 1997, James M. Carpenter Nest 970515‑9’ ‘ Metapolybia miltoni, Antena & Carpenter’; 1♀ (# MZSP 56898) ‘ Brazil, S.[ão] P.[aulo], Ribeirão Preto, 21°09’S, 47°51’W, 860 m, 15 may 1997, James M. Carpenter Nest, 970515‑9’ ‘ Metapolybia docilis Richards, det. J.M. Carpenter 1997’ ‘ Metapolybia miltoni Andena & Carpenter’.Published as part of Andrade, Tamires de O., Ramos, Kelli S., Onody, Helena C., dos Santos, Alvaro D. & Brandão, Carlos Roberto F., 2018, Type specimens of Pompiloidea, Thynnoidea and Vespoidea (Hymenoptera) deposited in the Museu de Zoologia da Universidade de São Paulo, Brazil, pp. 1-21 in Papéis Avulsos de Zoologia 58 on page 11, DOI: 10.11606/1807-0205/2018.58.39, http://zenodo.org/record/461350
A wave driver theory for vortical waves propagating across junctions with application to those between rigid and compliant walls
No full textA theory is described for propagation of vortical waves across alternate rigid and compliant panels. The structure in the fluid side at the junction of panels is a highly vortical narrow viscous structure which is idealized as a wave driver. The wave driver is modelled as a ‘half source cum half sink’. The incoming wave terminates into this structure and the outgoing wave emanates from it. The model is described by half Fourier–Laplace transforms respectively for the upstream and downstream sides of the junction. The cases below cutoff and above cutoff frequencies are studied. The theory completely reproduces the direct numerical simulation results of Davies & Carpenter (J. Fluid Mech., vol. 335, 1997, p. 361). Particularly, the jumps across the junction in the kinetic energy integral, the vorticity integral and other related quantities as obtained in the work of Davies & Carpenter are completely reproduced. Also, some important new concepts emerge, notable amongst which is the concept of the pseudo group velocity
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
O(d+1, d+1) enhanced double field theory
No full text© 2017, The Author(s). Double field theory yields a formulation of the low-energy effective action of bosonic string theory and half-maximal supergravities that is covariant under the T-duality group O(d, d) emerging on a torus T d . Upon reduction to three spacetime dimensions and dualisation of vector fields into scalars, the symmetry group is enhanced to O(d+1, d+1). We construct an enhanced double field theory with internal coordinates in the adjoint representation of O(d + 1, d + 1). Its section constraints admit two inequivalent solutions, encoding in particular the embedding of D = 6 chiral and non-chiral theories, respectively. As an application we define consistent generalized Scherk-Schwarz reductions using a novel notion of generalized parallelization. This allows us to prove the consistency of the truncations of D = 6, N= (1 1) and D = 6, N= (2 0) supergravity on AdS 3 × S 3
O(d+1, d+1) enhanced double field theory
No full text© 2017, The Author(s). Double field theory yields a formulation of the low-energy effective action of bosonic string theory and half-maximal supergravities that is covariant under the T-duality group O(d, d) emerging on a torus T d . Upon reduction to three spacetime dimensions and dualisation of vector fields into scalars, the symmetry group is enhanced to O(d+1, d+1). We construct an enhanced double field theory with internal coordinates in the adjoint representation of O(d + 1, d + 1). Its section constraints admit two inequivalent solutions, encoding in particular the embedding of D = 6 chiral and non-chiral theories, respectively. As an application we define consistent generalized Scherk-Schwarz reductions using a novel notion of generalized parallelization. This allows us to prove the consistency of the truncations of D = 6, N= (1 1) and D = 6, N= (2 0) supergravity on AdS 3 × S 3
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