59 research outputs found
A Very Unusual Presentation of Metastatic Colon Cancer
This case highlights two very rare complications of metastatic colorectal carcinoma. It
describes a 59 year old female with both cutaneous and endometrial metastases from colorectal
carcinoma. While both of these presentations are very unusual, they highlight the need to be vigilant
about the detection of metastatic complications during follow up
Deprotonation, insertion and isomerisation in the post-functionalisation of tris-pyridyl aluminates
ProducciĂłn CientĂficaPost-functionalisation of the aluminate anion [EtAl(6-R-2-py)3]â (6-R-2-py = 6-R-2-pyridyl, R = Me or Br) can be accomplished via nucleophilic addition of the pyridyl groups to the electrophilic C[double bond, length as m-dash]O group of aldehydes (RCH[double bond, length as m-dash]O) or by deprotonation of carboxylic acids (RCO2H). NMR spectroscopic and crystallographic studies show how 6-Me-2-py groups can detect chirality and reveal a new aspect of isomerism.Ministerio de EconomĂa, Industria y Competitividad - Agencia Estatal de InvestigaciĂłn - Fondo Social Europeo (Ramon y Cajal contract RG-R, RYC-2015-19035)
A Tris(3âpyridyl)stannane as a Building Block for Heterobimetallic Coordination Polymers and Supramolecular Cages
ProducciĂłn CientĂficaThe systematic assembly of supramolecular arrangements is a persistent challenge in modern coordination chemistry, especially where further aspects of complexity are concerned, as in the case of large molecular mixedâmetal arrangements. One targeted approach to such heterometallic complexes is to engineer metalâbased donor ligands of the correct geometry to build 3D arrangements upon coordination to other metals. This simple idea has, however, only rarely been applied to main group metalâbased ligand systems. Here, we show that the new, benchâstable tris(3âpyridyl)stannane ligand PhSn(3âPy)3 (3âPy=3âpyridyl) provides simple access to a range of heterometallic SnIV/transition metal complexes, and that the presence of weakly coordinating counter anions can be used to build discrete molecular arrangements involving anion encapsulation. This work therefore provides a building strategy in this area, which parallels that of supramolecular transition metal chemistry.Ministerio de EconomĂa, Industria y Competitividad - Agencia Estatal de InvestigaciĂłn - Fondo Social Europeo (Ramon y Cajal contract RGâR, RYCâ2015â19035)Ministerio de Ciencia, InnovaciĂłn y Universidades - Agencia Estatal de InvestigaciĂłn - FEDER - UniĂłn Europea (project PGC2018â096880âAâI00)
A General, Rhodium-Catalyzed, Synthesis of Deuterated Boranes and N-Methyl Polyaminoboranes
The rhodium complex [Rh(Ph2PCH2CH2CH2PPh2)(η6âFC6H5)][BArF4], 2, catalyzes BH/BD exchange between D2 and the boranes H3Bâ
NMe3, H3Bâ
SMe2 and HBpin, facilitating the expedient isolation of a variety of deuterated analogues in high isotopic purities, and in particular the isotopologues of Nâmethylamineâborane: R3Bâ
NMeR2 1âdx (R=H, D; x=0, 2, 3 or 5). It also acts to catalyze the dehydropolymerization of 1âdx to give deuterated polyaminoboranes. Mechanistic studies suggest a metalâbased polymerization involving an unusual hybrid coordination insertion chainâgrowth/stepâgrowth mechanism
The role of neutral Rh(PONOP)H, free NMe2H, boronium and ammonium salts in the dehydrocoupling of dimethylamine-borane using the cationic pincer [Rh(PONOP)(η2-H2)]+ catalyst
The Ï-amine-borane pincer complex [Rh(PONOP)(η1-H3B·NMe3)][BArF4] [2, PONOP = Îș3-NC5H3-2,6-(OPtBu2)2] is prepared by addition of H3B·NMe3 to the dihydrogen precursor [Rh(PONOP)(η2-H2)][BArF4], 1. In a similar way the related H3B·NMe2H complex [Rh(PONOP)(η1-H3B·NMe2H)][BArF4], 3, can be made in situ, but this undergoes dehydrocoupling to reform 1 and give the aminoborane dimer [H2BNMe2]2. NMR studies on this system reveal an intermediate neutral hydride forms, Rh(PONOP)H, 4, that has been prepared independently. 1 is a competent catalyst (2 mol%, âŒ30 min) for the dehydrocoupling of H3B·Me2H. Kinetic, mechanistic and computational studies point to the role of NMe2H in both forming the neutral hydride, via deprotonation of a Ï-amine-borane complex and formation of aminoborane, and closing the catalytic cycle by reprotonation of the hydride by the thus-formed dimethyl ammonium [NMe2H2]+. Competitive processes involving the generation of boronium [H2B(NMe2H)2]+ are also discussed, but shown to be higher in energy. Off-cycle adducts between [NMe2H2]+ or [H2B(NMe2H)2]+ and amine-boranes are also discussed that act to modify the kinetics of dehydrocoupling
A Tris(3-pyridyl)stannane as a Building Block for Heterobimetallic Coordination Polymers and Supramolecular Cages
The systematic assembly of supramolecular arrangements is a persistent challenge in modern coordination chemistry, especially where further aspects of complexity are concerned, as in the case of large molecular mixedâmetal arrangements. One targeted approach to such heterometallic complexes is to engineer metalâbased donor ligands of the correct geometry to build 3D arrangements upon coordination to other metals. This simple idea has, however, only rarely been applied to main group metalâbased ligand systems. Here, we show that the new, benchâstable tris(3âpyridyl)stannane ligand PhSn(3âPy)3 (3âPy=3âpyridyl) provides simple access to a range of heterometallic SnIV/transition metal complexes, and that the presence of weakly coordinating counter anions can be used to build discrete molecular arrangements involving anion encapsulation. This work therefore provides a building strategy in this area, which parallels that of supramolecular transition metal chemistry
A d10 Ag(i) amine-borane Ï-complex and comparison with a d8 Rh(i) analogue : Structures on the η1 to η2:η2 continuum
H3B·NMe3 Ï-complexes of d8 [(L1)Rh][BArF4] and d10 [(L1)Ag][BArF4] (where L1 = 2,6-bis-[1-(2,6-diisopropylphenylimino)ethyl]pyridine) have been prepared and structurally characterised. Analysis of the molecular and electronic structures reveal important but subtle differences in the nature of the bonding in these Ï-complexes, which differ only by the identity of the metal centre and the d-electron count. With Rh the amine-borane binds in an η2:η2 fashion, whereas at Ag the unsymmetrical {AgâŻH3B·NMe3} unit suggests a structure lying between the η2:η2 and η1 extremes
Re-visiting Meltsner: Policy Advice Systems and the Multi-Dimensional Nature of Professional Policy Analysis
10.2139/ssrn.15462511-2
Evolution of late-stage metastatic melanoma is dominated by aneuploidy and whole genome doubling
Although melanoma is initiated by acquisition of point mutations and limited focal copy number alterations in melanocytes-of-origin, the nature of genetic changes that characterise lethal metastatic disease is poorly understood. Here, we analyze the evolution of human melanoma progressing from early to late disease in 13 patients by sampling their tumours at multiple sites and times. Whole exome and genome sequencing data from 88 tumour samples reveals only limited gain of point mutations generally, with net mutational loss in some metastases. In contrast, melanoma evolution is dominated by whole genome doubling and large-scale aneuploidy, in which widespread loss of heterozygosity sculpts the burden of point mutations, neoantigens and structural variants even in treatment-naĂŻve and primary cutaneous melanomas in some patients. These results imply that dysregulation of genomic integrity is a key driver of selective clonal advantage during melanoma progression
Fingertip force control during bimanual object lifting in hemiplegic cerebral palsy
In the present study we examined unimanual and bimanual fingertip force control during grasping in children with hemiplegic cerebral palsy (CP). Participants lifted, transported and released an object with one hand or both hands together in order to examine the effect on fingertip force control for each hand separately and to determine whether any benefit exists for the affected hand when it performed the task concurrently with the less-affected hand. Seven children with hemiplegic CP performed the task while their movement and fingertip force control were measured. In the bimanual conditions, the weight of the instrumented objects was equal or unequal. The durations of the all temporal phases for the less-affected hand were prolonged during bimanual control compared to unimanual control. We observed close synchrony of both hands when the task was performed with both hands, despite large differences in duration between both hands when they performed separately. There was a marginal benefit for two of the five force related variables for the affected hand (grip force at onset of load force, and peak grip force) when it transported the object simultaneously with the less-affected hand. Collectively, these results corroborate earlier findings of reaching studies that showed slowing down of the less-affected hand when it moved together with the affected hand. A new finding that extends these studies is that bimanual tasks may have the potential to facilitate force control of the affected hand. The implications of these findings for recent rehabilitative therapies in children with CP that make use of bimanual training are discussed
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