The role of in-cylinder gas density and oxygen concentration on late spray mixing and soot oxidation processes

An analysis of in-cylinder gas density and oxygen mass concentration (YO 2) impact on the mixing and oxidation processes and the final soot emissions in conventional high temperature diffusive Diesel combustion conditions is presented in this paper. Parametrical tests were performed on a single cylinder heavy duty research engine. The density was modified adjusting the boost pressure following two approaches, maintaining the YO 2 either before or after the combustion process. The YO 2 was modified by diluting fresh air with exhaust gas maintaining a constant density. The possibility of controlling the soot emissions combining both parameters (YO 2 and density) is evaluated and, in a final part, the NO X emission results are also addressed. Results show that YO 2 has a strong effect on both mixing and oxidation processes while density affects principally the mixing process. Both parameters affect the final soot emissions. The density modification through adjustment of boost pressure modifies the trapped mass and has a strong impact on the evolution of YO 2 (thus on the evolution of the mixing process) during combustion. If the density is increased maintaining constant the YO 2 at the beginning of the combustion, the NO X-Soot trade-off is enhanced. © 2011 Elsevier Ltd.Benajes Calvo, JV.; Novella Rosa, R.; García Martínez, A.; Arthozoul ., SJL. (2011). The role of in-cylinder gas density and oxygen concentration on late spray mixing and soot oxidation processes. Energy. 36:1599-1611. doi:10.1016/j.energy.2010.12.071S159916113

Modulation of σ-Alkane Interactions in [Rh(L2)(alkane)]+ Solid-State Molecular Organometallic (SMOM) Systems by Variation of the Chelating Phosphine and Alkane : Access to η2,η2-σ-Alkane Rh(I), η1-σ-Alkane Rh(III) Complexes, and Alkane Encapsulation

Solid/gas single-crystal to single-crystal (SC-SC) hydrogenation of appropriate diene precursors forms the corresponding σ-alkane complexes [Rh(Cy2P(CH2)nPCy2)(L)][BArF 4] (n = 3, 4) and [RhH(Cy2P(CH2)2(CH)(CH2)2PCy2)(L)][BArF 4] (n = 5, L = norbornane, NBA; cyclooctane, COA). Their structures, as determined by single-crystal X-ray diffraction, have cations exhibiting Rh···H-C σ-interactions which are modulated by both the chelating ligand and the identity of the alkane, while all sit in an octahedral anion microenvironment. These range from chelating η2,η2 Rh···H-C (e.g., [Rh(Cy2P(CH2)nPCy2)(η2η2-NBA)][BArF 4], n = 3 and 4), through to more weakly bound η1 Rh···H-C in which C-H activation of the chelate backbone has also occurred (e.g., [RhH(Cy2P(CH2)2(CH)(CH2)2PCy2)(η1-COA)][BArF 4]) and ultimately to systems where the alkane is not ligated with the metal center, but sits encapsulated in the supporting anion microenvironment, [Rh(Cy2P(CH2)3PCy2)][COÅBArF 4], in which the metal center instead forms two intramolecular agostic η1 Rh···H-C interactions with the phosphine cyclohexyl groups. CH2Cl2 adducts formed by displacement of the η1-alkanes in solution (n = 5; L = NBA, COA), [RhH(Cy2P(CH2)2(CH)(CH2)2PCy2)(κ1-ClCH2Cl)][BArF 4], are characterized crystallographically. Analyses via periodic DFT, QTAIM, NBO, and NCI calculations, alongside variable temperature solid-state NMR spectroscopy, provide snapshots marking the onset of Rh···alkane interactions along a C-H activation trajectory. These are negligible in [Rh(Cy2P(CH2)3PCy2)][COÅBArF 4]; in [RhH(Cy2P(CH2)2(CH)(CH2)2PCy2)(η1-COA)][BArF 4], σC-H → Rh σ-donation is supported by Rh → σ∗C-H "pregostic" donation, and in [Rh(Cy2P(CH2)nPCy2)(η2η2-NBA)][BArF 4] (n = 2-4), σ-donation dominates, supported by classical Rh(dπ) → σ∗C-H π-back-donation. Dispersive interactions with the [BArF 4]- anions and Cy substituents further stabilize the alkanes within the binding pocket

η2-Alkene complexes of [Rh(PONOP-iPr)(L)]+ cations (L = COD, NBD, Ethene). Intramolecular alkene-assisted hydrogenation and dihydrogen complex [Rh(PONOP-iPr)(η-H2)].

Rhodium-alkene complexes of the pincer ligand κ3-C5H3N-2,6-(OPiPr2)2 (PONOP-iPr) have been prepared and structurally characterized: [Rh(PONOP-iPr)(η2-alkene)][BArF4] [alkene = cyclooctadiene (COD), norbornadiene (NBD), ethene; ArF = 3,5-(CF3)2C6H3]. Only one of these, alkene = COD, undergoes a reaction with H2 (1 bar), to form [Rh(PONOP-iPr)(η2-COE)][BArF4] (COE = cyclooctene), while the others show no significant reactivity. This COE complex does not undergo further hydrogenation. This difference in reactivity between COD and the other alkenes is proposed to be due to intramolecular alkene-assisted reductive elimination in the COD complex, in which the η2-bound diene can engage in bonding with its additional alkene unit. H/D exchange experiments on the ethene complex show that reductive elimination from a reversibly formed alkyl hydride intermediate is likely rate-limiting and with a high barrier. The proposed final product of alkene hydrogenation would be the dihydrogen complex [Rh(PONOP-iPr)(η2-H2)][BArF4], which has been independently synthesized and undergoes exchange with free H2 on the NMR time scale, as well as with D2 to form free HD. When the H2 addition to [Rh(PONOP-iPr)(η2-ethene)][BArF4] is interrogated using pH2 at higher pressure (3 bar), this produces the dihydrogen complex as a transient product, for which enhancements in the 1H NMR signal for the bound H2 ligand, as well as that for free H2, are observed. This is a unique example of the partially negative line-shape effect, with the enhanced signals that are observed for the dihydrogen complex being explained by the exchange processes already noted

A series of crystallographically characterized linear and branched σ-alkane complexes of rhodium : from propane to 3-methylpentane

We thank the EPSRC (EP/M024210, and the UK National Crystallography Service), the Leverhulme Trust (RPG-2015-447), and SGC Chemicals for funding, T. M. Boyd (York) for experimental assistance and useful discussions, and Dr. M. Chadwick (Imperial College) for the initial synthesis of [1-isoprene][BAr ] . This work used the ARCHER UK National Supercomputing Service ( http://www.archer.ac.uk ) and the Cirrus UK National Tier-2 HPC Service at the EPCC ( http://www.cirrus.ac.uk ) funded by the University of Edinburgh and the EPSRC (EP/P020267/1).Using solid-state molecular organometallic (SMOM) techniques, in particular solid/gas single-crystal to single-crystal reactivity, a series of σ-alkane complexes of the general formula [Rh(Cy2PCH2CH2PCy2)(ηn:ηm-alkane)][BArF4] have been prepared (alkane = propane, 2-methylbutane, hexane, 3-methylpentane; ArF = 3,5-(CF3)2C6H3). These new complexes have been characterized using single crystal X-ray diffraction, solid-state NMR spectroscopy and DFT computational techniques and present a variety of Rh(I)···H-C binding motifs at the metal coordination site: 1,2-η2:η2 (2-methylbutane), 1,3-η2:η2 (propane), 2,4-η2:η2 (hexane), and 1,4-η1:η2 (3-methylpentane). For the linear alkanes propane and hexane, some additional Rh(I)···H-C interactions with the geminal C-H bonds are also evident. The stability of these complexes with respect to alkane loss in the solid state varies with the identity of the alkane: from propane that decomposes rapidly at 295 K to 2-methylbutane that is stable and instead undergoes an acceptorless dehydrogenation to form a bound alkene complex. In each case the alkane sits in a binding pocket defined by the {Rh(Cy2PCH2CH2PCy2)}+ fragment and the surrounding array of [BArF4]- anions. For the propane complex, a small alkane binding energy, driven in part by a lack of stabilizing short contacts with the surrounding anions, correlates with the fleeting stability of this species. 2-Methylbutane forms more short contacts within the binding pocket, and as a result the complex is considerably more stable. However, the complex of the larger 3-methylpentane ligand shows lower stability. Empirically, there therefore appears to be an optimal fit between the size and shape of the alkane and overall stability. Such observations are related to guest/host interactions in solution supramolecular chemistry and the holistic role of 1°, 2°, and 3° environments in metalloenzymes.Peer reviewe

Access and quality of biomarker testing for precision oncology in Europe

BACKGROUND Predictive biomarkers are essential for selecting the best therapeutic strategy in patients with cancer. The International Quality Network for Pathology, the European Cancer Patient Coalition and the European Federation of Pharmaceuticals Industries and Associations evaluated the access to and quality of biomarker testing across Europe. METHODS Data sources included surveys of 141 laboratory managers and 1.665 patients, and 58 in-depth interviews with laboratory managers, physicians and payers. Four access metrics (laboratory access, test availability, test reimbursement, test order rate) and three quality metrics (quality scheme participation, laboratory accreditation, test turnaround time) were applied to rank the results. RESULTS The access to precision medicines is higher in countries with public national reimbursement processes in place. Lack of diagnostic laboratory infrastructure, inefficient organization and/or insufficient public reimbursement narrow the access to single biomarker tests in many European countries. In countries with limited public reimbursement, pharma and patients' out of pocket were the primary funding sources for testing. Uptake of multi-biomarker next generation sequencing (NGS) is highly varied, ranging from 0% to >50%. Financial constraints, a lack of NGS testing capabilities and the failure to include NGS testing in the guidelines represent the main barriers to NGS implementation. The quality of biomarker testing is highest in Western and Northern Europe, with more than 90% of laboratories participating in quality assurance schemes. CONCLUSIONS Our data clearly indicate the need for a call to action to ensure the clinical implementation of precision medicine in Europe

Cross-Resistance to Abiraterone and Enzalutamide in Castration Resistance Prostate Cancer Cellular Models Is Mediated by AR Transcriptional Reactivation

Androgen deprivation therapy (ADT) and novel hormonal agents (NHAs) (Abiraterone and Enzalutamide) are the goal standard for metastatic prostate cancer (PCa) treatment. Although ADT is initially effective, a subsequent castration resistance status (CRPC) is commonly developed. The expression of androgen receptor (AR) alternative splicing isoforms (AR-V7 and AR-V9) has been associated to CRPC. However, resistance mechanisms to novel NHAs are not yet well understood. Androgen-dependent PCa cell lines were used to generate resistant models to ADT only or in combination with Abiraterone and/or Enzalutamide (concomitant models). Functional and genetic analyses were performed for each resistance model by real-time cell monitoring assays, flow cytometry and RT-qPCR. In androgen-dependent PCa cells, the administration of Abiraterone and/or Enzalutamide as first-line treatment involved a critical inhibition of AR activity associated with a significant cell growth inhibition. Genetic analyses on ADT-resistant PCa cell lines showed that the CRPC phenotype was accompanied by overexpression of AR full-length and AR target genes, but not necessarily AR-V7 and/or AR-V9 isoforms. These ADT resistant cell lines showed higher proliferation rates, migration and invasion abilities. Importantly, ADT resistance induced cross-resistance to Abiraterone and/or Enzalutamide. Similarly, concomitant models possessed an elevated expression of AR full-length and proliferation rates and acquired cross-resistance to its alternative NHA as second-line treatment.Instituto de Salud Carlos III PI17/00989European Regional Development Fund "A way to build Europe"Ramon y Cajal - Ministry of Economy and Competitiveness RYC-2015-18382Ministry of Education, Culture and Sport FPU14/05461University of Granad

Transforming Growth Factor-β3 Regulates Adipocyte Number in Subcutaneous White Adipose Tissue.

White adipose tissue (WAT) mass is determined by adipocyte size and number. While adipocytes are continuously turned over, the mechanisms controlling fat cell number in WAT upon weight changes are unclear. Herein, prospective studies of human subcutaneous WAT demonstrate that weight gain increases both adipocyte size and number, but the latter remains unaltered after weight loss. Transcriptome analyses associate changes in adipocyte number with the expression of 79 genes. This gene set is enriched for growth factors, out of which one, transforming growth factor-β3 (TGFβ3), stimulates adipocyte progenitor proliferation, resulting in a higher number of cells undergoing differentiation in vitro. The relevance of these observations was corroborated in vivo where Tgfb3+/- mice, in comparison with wild-type littermates, display lower subcutaneous adipocyte progenitor proliferation, WAT hypertrophy, and glucose intolerance. TGFβ3 is therefore a regulator of subcutaneous adipocyte number and may link WAT morphology to glucose metabolism

Graphene foam functionalized with electrodeposited nickel hydroxide for energy applications

The need of new systems for the storage and conversion of renewable energy sources is fueling the research in supercapacitors. In this work, we propose a low temperature route for the synthesis of electrodes for these supercapacitors: electrodeposition of a transition metal hydroxide-Ni(OH)₂ on a graphene foam. This electrode combines the superior mechanical and electrical properties of graphene, the large specific surface area of the foam and the large pseudocapacitance of Ni(OH)₂. We report a specific capacitance up to 900 F/g as well as specific power and energy comparable to active carbon electrodes. These electrodes are potential candidates for their use in energy applications