TAP Reactor Development and Application in the Kinetic Characterization of Catalysts for Heterogeneously Catalyzed Gas Phase Reactions

This manuscript describes the application and further development of the TAP technique in kinetic characterization of heterogeneous catalysis. The major application of TAP systems is to study mechanisms, kinetics and transport phenomena in heterogeneous catalysis, all of which is made possible by the sub-millisecond time resolution. Furthermore, the kinetic information obtained can be used to gain an insight into the mechanism occurring over the catalyst system. This is advantageous as heterogeneous catalysts with an improved efficiency can be developed as a result. TAP kinetic studies are carried out at low pressure (~1x10-7 mbar) and TAP pulses are sufficiently small (1013-1015 molecules) so as to maintain this low pressure. The use of a small number of molecules in comparison to the total number of active sites means the state of the catalyst remains relatively unchanged. The use of the low intensity pulses also makes the pressure gradient negligible and so allows the TAP reactor system to operate in the Knudsen Diffusion regime, where gas-gas reactions are eliminated. Hence only gas-catalyst reactions are investigated and, by the use of moment analysis of observed exit flow, rate constants of elementary steps of the reaction can be obtained.

In this manuscript, two attempts to further the TAP technique are reported. Firstly, the work undertaken at QUB to attempt to control the number of molecules of condensable reagents that can be pulsed during a TAP pulse experiment is disclosed. Secondly, a collaborative project with SAI Ltd Manchester is discussed in a separate chapter, where technical details and validation of a customised time of flight mass spectrometer (ToF MS) for the QUB TAP-1 system are reported. A collaborative project with Cardiff Catalysis Institute focusing on the study of CO oxidation over hopcalite catalysts is also reported. The analysis of the experimental results has provided an insight into the possible mechanism of the oxidation of CO over these catalysts. A correction function has also been derived which accounts for the adsorption of reactant molecules over inert materials that are used for the reactor packing in TAP experiments. This function was then applied to the selective reduction of O2 in a H2 rich ethene feed, so that more accurate TAP moment based analysis could be conducted.

Hypofractionated radiotherapy versus conventionally fractionated radiotherapy for patients with intermediate-risk localised prostate cancer: 2-year patient-reported outcomes of the randomised, non-inferiority, phase 3 CHHiP trial

BACKGROUND: Patient-reported outcomes (PROs) might detect more toxic effects of radiotherapy than do clinician-reported outcomes. We did a quality of life (QoL) substudy to assess PROs up to 24 months after conventionally fractionated or hypofractionated radiotherapy in the Conventional or Hypofractionated High Dose Intensity Modulated Radiotherapy in Prostate Cancer (CHHiP) trial.

METHODS: The CHHiP trial is a randomised, non-inferiority phase 3 trial done in 71 centres, of which 57 UK hospitals took part in the QoL substudy. Men with localised prostate cancer who were undergoing radiotherapy were eligible for trial entry if they had histologically confirmed T1b-T3aN0M0 prostate cancer, an estimated risk of seminal vesicle involvement less than 30%, prostate-specific antigen concentration less than 30 ng/mL, and a WHO performance status of 0 or 1. Participants were randomly assigned (1:1:1) to receive a standard fractionation schedule of 74 Gy in 37 fractions or one of two hypofractionated schedules: 60 Gy in 20 fractions or 57 Gy in 19 fractions. Randomisation was done with computer-generated permuted block sizes of six and nine, stratified by centre and National Comprehensive Cancer Network (NCCN) risk group. Treatment allocation was not masked. UCLA Prostate Cancer Index (UCLA-PCI), including Short Form (SF)-36 and Functional Assessment of Cancer Therapy-Prostate (FACT-P), or Expanded Prostate Cancer Index Composite (EPIC) and SF-12 quality-of-life questionnaires were completed at baseline, pre-radiotherapy, 10 weeks post-radiotherapy, and 6, 12, 18, and 24 months post-radiotherapy. The CHHiP trial completed accrual on June 16, 2011, and the QoL substudy was closed to further recruitment on Nov 1, 2009. Analysis was on an intention-to-treat basis. The primary endpoint of the QoL substudy was overall bowel bother and comparisons between fractionation groups were done at 24 months post-radiotherapy. The CHHiP trial is registered with ISRCTN registry, number ISRCTN97182923.

FINDINGS: 2100 participants in the CHHiP trial consented to be included in the QoL substudy: 696 assigned to the 74 Gy schedule, 698 assigned to the 60 Gy schedule, and 706 assigned to the 57 Gy schedule. Of these individuals, 1659 (79%) provided data pre-radiotherapy and 1444 (69%) provided data at 24 months after radiotherapy. Median follow-up was 50·0 months (IQR 38·4-64·2) on April 9, 2014, which was the most recent follow-up measurement of all data collected before the QoL data were analysed in September, 2014. Comparison of 74 Gy in 37 fractions, 60 Gy in 20 fractions, and 57 Gy in 19 fractions groups at 2 years showed no overall bowel bother in 269 (66%), 266 (65%), and 282 (65%) men; very small bother in 92 (22%), 91 (22%), and 93 (21%) men; small bother in 26 (6%), 28 (7%), and 38 (9%) men; moderate bother in 19 (5%), 23 (6%), and 21 (5%) men, and severe bother in four (<1%), three (<1%) and three (<1%) men respectively (74 Gy vs 60 Gy, ptrend=0.64, 74 Gy vs 57 Gy, ptrend=0·59). We saw no differences between treatment groups in change of bowel bother score from baseline or pre-radiotherapy to 24 months.

INTERPRETATION: The incidence of patient-reported bowel symptoms was low and similar between patients in the 74 Gy control group and the hypofractionated groups up to 24 months after radiotherapy. If efficacy outcomes from CHHiP show non-inferiority for hypofractionated treatments, these findings will add to the growing evidence for moderately hypofractionated radiotherapy schedules becoming the standard treatment for localised prostate cancer.

FUNDING: Cancer Research UK, Department of Health, and the National Institute for Health Research Cancer Research Network.

MErCuRIC1: A Phase I study of MEK1/2 inhibitor PD-0325901 with cMET inhibitor crizotinib in RASMT and RASWT (with aberrant c-MET) metastatic colorectal cancer (mCRC) patients.

Background: RAS is mutated (RASMT) in ~55% of mCRC, and phase III studies have shown that patients harbouring RAS mutations do not benefit from anti-EGFR MoAbs. In addition, ~50% of RAS Wild Type (RASWT) will not benefit from the addition of an EGFR MoAb to standard chemotherapy. Hence, novel treatment strategies are urgently needed for RASMT and > 50% of RASWT mCRC patients. c-MET is overexpressed in ~50-60%, amplified in ~2-3% and mutated in ~3-5% of mCRC. Recent preclinical studies have shown that c-MET is an important mediator of resistance to MEK inhibitors (i) in RASMT mCRC, and that combined MEKi/METi resulted in synergistic reduction in tumour growth in RASMT xenograft models (1). A number of recent studies have highlighted the role of c-MET in mediating primary/secondary resistance to anti-EGFR MoAbs in mCRC, suggesting that patient with RASWT tumours with aberrant c-MET (RASWT/c-MET+) may benefit from anti-c-MET targeted therapies (2). These preclinical data supported the further clinical evaluation of combined MEKi/METi treatment in RASMT and RASWT CRC patients with aberrant c-MET signalling (overexpression, amplification or mutation; RASWT/c-MET+). Methods: MErCuRIC1 is a phase I combination study of METi crizotinib with MEKi PD-0325901. The dose escalation phase, utilizing a rolling six design, recruits 12-24 patients with advanced solid tumours and aims to assess safety/toxicity of combination, recommended phase II (RPII) dose, pharmacokinetics (PK) and pharmacodynamics (PD) (pERK1/2 in PBMC and tumour; soluble c-MET). In the dose expansion phase an additional 30-42 RASMT and RASWT/c-MET mCRC patients with biopsiable disease will be treated at the RPII dose to further evaluate safety, PK, PD and treatment response. In the dose expansion phase additional biopsy and blood samples will be obtained to define mechanisms of response/resistance to crizotinib/PD-0325901 therapy. Enrolment into the dose escalation phase began in December 2014 with cohort 1 still ongoing. EudraCT registry number: 2014-000463-40. (1) Van Schaeybroeck S et al. Cell Reports 2014;7(6):1940-55; (2) Bardelli A et al. Cancer Discov 2013;3(6):658-73. Clinical trial information: 2014-000463-40.

Improved electrochemical performance of Sr2Fe1.5Mo0.4Nb0.1O6-δ -Sm0.2Ce0.8O2-δ composite cathodes by a one-pot method for intermediate temperature solid oxide fuel cells

In this paper, Sr₂Fe_1.5Mo_0.4Nb_0.1O_6-δ (SFMNb)-xSm_0.2Ce_0.8O_2-δ (SDC) (x = 0, 20, 30, 40, 50 wt%) composite cathode materials were synthesized by a one-pot combustion method to improve the electrochemical performance of SFMNb cathode for intermediate temperature solid oxide fuel cells (IT-SOFCs). The fabrication of composite cathodes by adding SDC to SFMNb is conducive to providing extended electrochemical reaction zones for oxygen reduction reactions (ORR). X-ray diffraction (XRD) demonstrates that SFMNb is chemically compatible with SDC electrolytes at temperature up to 1100 °C. Scanning electron microscope (SEM) indicates that the SFMNb-SDC composite cathodes have a porous network nanostructure as well as the single phase SFMNb. The conductivity and thermal expansion coefficient of the composite cathodes decrease with the increased content of SDC, while the electrochemical impedance spectra (EIS) exhibits that SFMNb-40SDC composite cathode has optimal electrochemical performance with low polarization resistance (R_p) on the La_0.9Sr_0.1Ga_0.8Mg_0.2O₃ electrolyte. The R_p of the SFMNb-40SDC composite cathode is about 0.047 Ω cm² at 800 °C in air. A single cell with SFMNb-40SDC cathode also displays favorable discharge performance, whose maximum power density is 1.22 W cm^-2 at 800 °C. All results indicate that SFMNb-40SDC composite material is a promising cathode candidate for IT-SOFCs.

Reactions of atomic and molecular ions with acetone, 1,1,1- trifluoroacetone, and hexafluoroacetone: An investigation of the effects of molecular structure on the dynamics and kinetics of ion-molecule reactions

A selected ion flow tube study of the reactions of a series of gas-phase atomic cations (S⁺, Xe⁺, O⁺, Kr⁺, N⁺, Ar⁺ and Ne⁺) and molecular ions (SF _n⁺ (n = 1-5), CF_n⁺ (n = 1-3), CF₂Cl⁺, H₃O⁺, NO⁺, N ₂O⁺, CO₂⁺, CO⁺, and N₂⁺) spanning a large range of recombination energies (6.3-21.6 eV), with acetone, 1,1,1-trifluoroacetone, and hexafluoroacetone has been undertaken with the objective of exploring the nature of the reaction ion chemistry as the methyl groups in acetone are substituted for CF₃. The reaction rate coefficients and product ion branching ratios for all 66 reactions, measured at 298 K, are reported. The experimental reaction rate coefficients are compared to theoretically calculated collisional values. Several distinct reaction processes were observed among the large number of reactions studied, including charge transfer (non-dissociative and dissociative), abstraction, ion-molecule associations and, in the case of the reactions involving the reagent ion H₃O⁺, proton transfer.