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Background Integrase strand transfer inhibitors (INSTIs) are recommended by international guidelines as first-line therapy in antiretroviral-naive and -experienced HIV-1-infected patients. Objectives This study aimed at evaluating the prevalence at failure of INSTI-resistant variants and the impact of baseline minority resistant variants (MiRVs) on the virological response to an INSTI-based regimen. Methods Samples at failure of 134 patients failing a raltegravir-containing (n = 65), an elvitegravir-containing (n = 20) or a dolutegravir-containing (n = 49) regimen were sequenced by Sanger sequencing and ultra-deep sequencing (UDS). Baseline samples of patients with virological failure (VF) (n = 34) and of those with virological success (VS) (n = 31) under INSTI treatment were sequenced by UDS. Data were analysed using the SmartGene platform, and resistance was interpreted according to the ANRS algorithm version 27. Results At failure, the prevalence of at least one INSTI-resistant variant was 39.6% by Sanger sequencing and 57.5% by UDS, changing the interpretation of resistance in 17/134 (13%) patients. Among 53 patients harbouring at least one resistance mutation detected by both techniques, the most dominant INSTI resistance mutations were N155H (45%), Q148H/K/R (23%), T97A (19%) and Y143C (11%). There was no difference in prevalence of baseline MiRVs between patients with VF and those with VS. MiRVs found at baseline in patients with VF were not detected at failure either in majority or minority mutations. Conclusions UDS is more sensitive than Sanger sequencing at detecting INSTI MiRVs at treatment failure. The presence of MiRVs at failure could be important to the decision to switch to other INSTIs. However, there was no association between the presence of baseline MiRVs and the response to INSTI-based therapies in our study.

Background In recent years, dolutegravir monotherapy has been explored as a drug-reduced regimen for HIV patients. Methods This was a retrospective observational study, including patients virologically suppressed for ≥6 months, without previous virological failure (VF) under integrase inhibitors (INIs), who had been switched to dolutegravir monotherapy (50 mg/day). The primary aim was to report the proportion of VF at week 48 (W48) and week 96 (W96) of dolutegravir monotherapy. The evolution from baseline to W48 of residual viraemia on ultra-deep sequencing and HIV DNA was also evaluated. Results Sixty-one patients were included. Prior to switching to dolutegravir monotherapy, they had a median (IQR) of 15.4 (6.5–19.9) years of antiretroviral exposure, 5.8 (3.2–10.3) years of viral suppression and 687 (461–848) CD4+ cells/mm3. They remained on dolutegravir monotherapy for a median (IQR) of 100 (29–148) weeks. Forty-two out of 61 patients (68.9%) reached W48 and 32 out of 61 patients (52.5%) reached W96. VF occurred in three patients, with the emergence of INI resistance. VF occurred before W24 and in patients pre-exposed to INIs. At W48, the probability of VF (Kaplan–Meier analysis) was 5.6% (95% CI = 1.8%–16.4%). The same result was obtained at W96. Detectable residual viraemia did not increase and median HIV DNA did not change significantly (2.4 log/106 cells at baseline and 2.3 log/106 cells at W48). Dolutegravir plasma concentration was above the IC90 in 41/41 samples, from 22 patients. Conclusions Long-term follow-up showed a low risk of VF under dolutegravir monotherapy, in a selected population of patients with previous long-term virological suppression and low HIV reservoir.

Objectives To investigate the dynamics of HIV-1 variants archived in cells harbouring drug resistance-associated mutations (DRAMs) to lamivudine/emtricitabine, etravirine and rilpivirine in patients under effective ART free from selective pressure on these DRAMs, in order to assess the possibility of recycling molecules with resistance history. Patients and methods We studied 25 patients with at least one DRAM to lamivudine/emtricitabine, etravirine and/or rilpivirine identified on an RNA sequence in their history and with virological control for at least 5 years under a regimen excluding all drugs from the resistant class. Longitudinal ultra-deep sequencing (UDS) and Sanger sequencing of the reverse transcriptase region were performed on cell-associated HIV-1 DNA samples taken over the 5 years of follow-up. Results Viral variants harbouring the analysed DRAMs were no longer detected by UDS over the 5 years in 72% of patients, with viruses susceptible to the molecules of interest found after 5 years in 80% of patients with UDS and in 88% of patients with Sanger. Residual viraemia with

OBJECTIVES In resource-limited settings, few data are available on virological failure after long-term first-line antiretroviral therapy. This study characterized the genotypic resistance patterns at the time of failure after at least 36 months of a first-line regimen in Mali, West Africa. METHODS Plasma samples from 84 patients who were receiving first-line antiretroviral treatment and with an HIV-1 RNA viral load (VL) >1000 copies/mL were analysed. Genotypic resistance testing was performed and HIV-1 drug resistance was interpreted according to the latest version of the National Agency for HIV and Hepatitis Research algorithm. RESULTS At the time of resistance testing, patients had been treated for a median of 60 months (IQR 36-132 months) and had a median CD4 cell count of 292 cells/mm(3) (IQR 6-1319 cells/mm(3)), a median HIV-1 RNA level of 28266 copies/mL (IQR 1000-2 93 495 copies/mL) and a median genotypic susceptibility score of 1 (IQR 1-4). The prevalence of nucleoside reverse transcriptase inhibitor (NRTI) and non-nucleoside reverse transcriptase inhibitor (NNRTI) resistance mutations was 78% and 82%, respectively. Viruses were resistant to at least one drug in 92% of cases. Although etravirine and rilpivirine were not used in the first-line regimens, viruses were resistant to etravirine in 34% of cases and to rilpivirine in 49% of cases. The treatment duration, median number of NRTI and NNRTI mutations and some reverse transcriptase mutations (T215Y/F/N, L210W, L74I, M41L and H221Y) were associated with the VL at virological failure. CONCLUSIONS This study demonstrated a high level of resistance to NRTIs and NNRTIs, compromising second-generation NNRTIs, for patients who stayed on long-term first-line regimens. It is crucial to expand the accessibility of virological testing in resource-limited settings to limit the expansion of resistance and preserve second-line treatment efficacy.

Recent studies have independently implicated the chemokine CXCL12 and its receptors, CXCR4 and CXCR7, in the pathophysiology of Kaposi sarcoma (KS).We investigated whether the CXCL12/CXCR4-CXCR7 protein trio could constitute KS biomarkers.Endothelial and spindle cells positive for CXCL12/CXCR4-CXCR7, human herpesvirus-8 latency-associated nuclear antigen (LANA), Ki67 antigen (proliferation) and vascular endothelial growth factor (VEGF) were quantitated in skin lesions from patients with AIDS-associated KS, patients with classic KS and patients with angiomas, using immunohistochemistry and quantitative image analysis (16, 21 and 20 skin lesions, respectively). Plasma CXCL12 concentrations were measured by enzyme-linked immunosorbent assay from 20 patients with AIDS-KS, 12 HIV-infected patients without KS and 13 healthy donors' samples.Cells positive for CXCL12, CXCR4, CXCR7, LANA, Ki67 and VEGF were significantly enriched in patients with AIDS-associated KS and classic KS vs. angiomas (P0·001), and in nodular vs. macular/papular KS lesions (P0·05). CXCL12, CXCR4 and CXCR7 detection correlated with LANA, Ki67 and VEGF detection (r0·4; P0·05). However, plasma CXCL12 concentrations did not differ between patients with AIDS-associated KS, HIV-infected patients without KS, and healthy donors.The CXCL12/CXCR4-CXCR7 trio is upregulated in KS and correlates with KS pathophysiological markers and the severity of skin lesions. Histological assessment of the CXCL12 axis could serve as a valuable biomarker for KS diagnosis and progression.

International audience; Background Reducing drug burden is a key challenge for achieving lifelong suppressive HIV therapy. Dolutegravir, with a high potency, long half-life and high genetic barrier, offers potential for monotherapy.Methods This observational single-centre study enrolled all patients with HIV RNA (viral load) 350 cells/mm3 and with no failure under integrase inhibitor therapy who had switched from suppressive ART to dolutegravir monotherapy (50 mg/day). Primary outcome was proportion of patients with viral load

OBJECTIVES There are few data on clinical and virological factors associated with maraviroc virological response (VR) in clinical practice. This study aimed to identify factors associated with VR in 94 treatment-experienced, but CCR5 inhibitor-naive, HIV-1 patients switched to maraviroc-containing regimens. METHODS Patients with HIV-1 RNA viral load (VL)

International audience; Objectives In the context of a rilpivirine/emtricitabine/tenofovir disoproxil fumarate switch in HIV-1-infected patients with at least 1 year of virological success, we determined whether proviral DNA is an alternative to plasma HIV RNA for resistance genotyping.Methods Resistance-associated mutations (RAMs) in DNA after at least 1 year of virological success [viral load (VL) 50 copies/mL). Kappa's coefficient was used to measure agreement between the DNA and RNA genotypes.Results In patients without VF (n = 130) and with VF (n = 114), RNA and DNA showed resistance to at least one drug of the rilpivirine/emtricitabine/tenofovir disoproxil fumarate combination in 8% and 9% and in 60% and 45%, respectively. For rilpivirine RAMs, correlation between RNA and DNA was higher in patients without VF than in patients with VF (kappa = 0.60 versus 0.19, P = 0.026). Overall, the prevalence of RAMs was lower in DNA than in RNA.Conclusions Incomplete information provided by the DNA genotypic test is more notable in patients with VF, suggesting that all resistance mutations associated with prior VF have not been archived in the proviral DNA or decreased to a level below the threshold of detection. In the case where no historical plasma genotypic test is available, DNA testing might be useful to rule out switching to rilpivirine/emtricitabine/tenofovir disoproxil fumarate.

There is evidence that HIV-1 evolution under maraviroc (MVC) pressure can lead to the selection of either X4-tropic variants and/or R5-tropic, MVC-resistant isolates. However, the viral dynamics of HIV-1 variants in patients with virological failure (VF) on MVC-containing regimens remain poorly studied. Here, we investigated the V3 loop evolution of HIV-1 on MVC in relation to coreceptor usage and the nature of HIV-1 quasispecies before MVC therapy using bulk population sequences and ultradeep sequencing. The majority of patients had no detectable minority X4 variant at baseline. The evolution of tropism was followed up until VF and showed three possibilities for viral evolution in these patients: emergence of preexisting X4 variants, de novo selection of R5 variants presenting V3 loop mutations, or replication of R5 variants without selection of known mutations.

A novel but fairly simple approach has been used to elucidate the effect of Li+ promotion of 5 wt% Pd/SiO2 [(Li/Pd)atomic = 0, 1, 2, 4] by using a set of three distinct reactions (CO hydrogenation, isobutylene hydrogenation, and ethane hydrogenolysis) in addition to H2 TPD, CO chemisorption, XRD, and TEM. The results were used to indicate the degree of metal surface blockage by the promoter and to better understand how Li+ goes about affecting Pd catalysis, especially CO hydrogenation which is known to be greatly modified. Li+ promotion decreased the strength of H2 adsorption and enhanced CO adsorption on Pd/SiO2. Additionally, it significantly decreased the hydrogenation (in the presence of CO) and ethane hydrogenolysis activities of Pd/SiO2 relative to those of the unpromoted catalyst, with the activities decreasing monotonically with increasing Li+ loading. Isobutylene hydrogenation results suggest Li+ blockage of some of the active Pd sites. Steady-state isotopic transient kinetic analysis (SSITKA) of isobutylene hydrogenation in the presence of CO indicates that surface coverage by CO was significantly enhanced by Li+ promotion. The simultaneous enhancement and suppression of CO and H2 adsorption, respectively, coupled with active site blockage by Li+ resulted in olefin hydrogenation appearing to behave like a structure sensitive reaction. Ethane hydrogenolysis results indicate a nonuniform distribution of the promoter on Pd as well as its probable dispersion on the surface of the support as well. Despite the fact that site blockage resulted in a decrease in the hydrogenation and ethane hydrogenolysis activities of Li-Pd/SiO2 (Li/Pd = 1), an increase in the rate of methanol formation was observed. This increase in the methanol formation rate with low levels of Li+ promotion can be attributed to an increase in the number of active sites or in the coverage of the active sites by the surface intermediates since TEM indicated no change in Pd particle size distribution. Higher loadings of Li+ (Li/Pd ≥ 2) resulted in a decrease in methanol formation.

Objective: Activation of AT2 angiotensin II receptor release cytochrome P-450 arachidonic acid metabolites (CYP-AA). The presence of the AT2 receptor and its ability to mediate renal vasodilation through CYP-AA metabolites were evaluated. Methods: Vascular response to angiotensin II in the isolated perfused kidney of the rat was evaluated in the absence and presence of angiotensin II AT1 and AT2 receptor blockers. Results: Blockade of the AT1 receptor unmasked a vasodilatory response that was inhibited by AT2 receptor blockade and AA metabolism. Conclusion: The findings indicate that blockade of the AT1 angiotensin II receptor, activation of AT2 receptors, releases CYP-AA metabolites that induce renal vasodilation.

Catalytic combustion of natural gas, for applications such as gas turbine operation, is one means of reducing NO{sub x} emissions that are of increasing environmental concern. The high temperature, ca 1200{degrees}C, involved in the catalytic combustor for gas turbine operation requires the use of metal oxide catalysts because of their high thermal stability compared to noble metals. This paper reports the catalytic properties of Sr-substituted LaCoO{sub 3} perovskites for the combustion of methane and NO{sub x} formation/reduction. The NO{sub x} emissions under catalytic combustion conditions were less than 2 ppm at temperatures up to 1100{degrees}C. The La{sub 1{minus}x}Sr{sub x}CoO{sub 3} perovskites have considerable activity for NO{sub x} decomposition and reduction under combustion conditions. Addition of strontium to the perovskite increased the activity for both methane combustion and NO{sub x} reduction. Temperature Programmed Reduction and oxygen-Temperature Programmed Desorption results show an increase lattice oxygen mobility with increased strontium substitution in the LaCoO{sub 3} perovskites. The effect of strontium substitution on methane combustion and NO{sub x} reduction will be presented.

During the eleventh quarter of this project, significant time was spent in reinstalling the reactor system in Altamira`s new location. In addition, the experimental system was modified in order to include a shorter furnace, 8-inch heated length compared to the original 24-inch heated length. With the shorter reactor, contact times in the order of milliseconds can be achieved. Following the physical modification, a number of gas phase experiments were conducted in order to verify the operation of the system. As expected, conversions were typically lower in the shorter furnace. Preliminary investigations of the initiation of pyrolysis by a solid surface using {alpha}-Al{sub 2}O{sub 3} were also carried out during this reporting period.

A series of cobalt-based F-T catalysts supported on alumina and silica were prepared with different loadings of Zr and different sequences of impregnation of Co and Zr. All catalysts were extensively characterized by different methods. The catalysts were evaluated in terms of their activity and selectivity both in fixed bed and slurry bubble column reactors. Addition of ZrO{sub 2} to both Co/SiO{sub 2} and Co/Al{sub 2}O{sub 3} catalysts resulted in at least a twofold increase in the catalyst activity for F-T synthesis in the fixed bed reactor. In the slurry bubble column reactor, a similar promotion effect was observed for the SiO{sub 2}-supported catalysts, while the addition of Zr to a cobalt/alumina catalyst had a less significant effect.

Based on the information provided in patents assigned to Gulf, Shell, Exxon, and Statoil, a series of catalysts has been prepared consisting of 12--20 wt. % cobalt, a second metal promoter (Ru or Re), and an oxide promoter such as lanthana, zirconia, or alkali oxide, the support being alumina, silica, or titania. All catalysts have been extensively characterized by different methods. The catalysts have been evaluated in terms of their activity, selectivity both in a fixed bed reactor and in a slurry bubble column reactor, and the results correlated with their physico-chemical properties.

A series of cobalt-based F-T catalysts supported on alumina, silica, or titania were prepared with Ru and/or ZrO{sub 2} as promoters. All catalysts were extensively characterized by different methods. The catalysts were evaluated in terms of their activity and selectivity both in fixed bed and slurry bubble column reactors. Similar trends were observed in both reactors for support effects. However, this was not the case for the effects of promoters. Noble metal promotion effects were much more accentuated in the fixed bed reactor than under slurry bubble column reaction conditions, while the opposite seemed to hold true in the case of ZrO{sub 2} promotion effects, at least for SiO{sub 2}-supported Co catalysts.

Figure 7 summarizes the carbon selectivities observed towards the main products. During Period IV, the main products observed were the heavy hydrocarbons, with selectivity for MTBE being less than 3--5%. The only time that high MTBE selectivity was noted was during period III, when the i-butylene feed was shut-off. The large amounts of heavy products and the low selectivity to MTBE were surprising in view of our previous experiments in the gas phase and the high methanol-to-i-butylene ratio used in these runs. In the gas-phase and with methanol/i-butylene = 0.5, over 95% selectivity to MTBE was observed with this catalyst at this temperature. The higher level of methanol used here would be expected to further improve the MTBE selectivity. Perhaps one reason for the poor MTBE selectivity relates to the relative solubilities of the reactants in the Synfluid changing the effective methanol/i-butylene ratio. Figure 8 shows the relative molar concentration of i-butylene during Period III. At 180 minutes, the gas supply of that reactant was shut-off, yet the analyses show that i-butylene continued to elute from the reactor for at least an additional 2 hours. It seems reasonable that the i-butylene is highly soluble in the Synfluid since they aremore » both nonpolar hydrocarbons. Likewise, one would expect the methanol to not be quite as soluble and thus the methanol/i-butylene ratio in the liquid medium may be very low, favoring the oligomerization of i-butylene. Indeed, the only time that MTBE selectivity was high was after the i-butylene supply was shut-off. We intend to quantify these solubilities in future experiments.« less

The objective of this project is to investigate three possible routes to the formation of ethers, in particular methyl tert-butyl ether (MTBE), during slurry phase Fischer-Tropsch reaction. The three reaction schemes to be investigated are: Addition of isobutylene during the formation of methanol and/or higher alcohols directly from CO and H{sub 2} during slurry-phase Fischer-Tropsch. Addition of isobutylene to FT liquid products including alcohols in a slurry-phase reactor containing an MTBE or other acid catalyst. Addition of methanol to slurry phase FT synthesis making iso-olefins.

The objective of this project is to investigate three possible routes to the formation of ethers, in particular methyl tert-butyl (MTBE), during slurry phase Fischer-Tropsch reaction. The three reaction schemes to be investigated are: addition of i-butylene during the formation of methanol and/or higher alcohols directly from CO and H{sub 2} during slurry-phase Fischer-Tropsch; addition of i-butylene to FT liquid products including alcohols in a slurry-phase reactor containing an MTBE or other acid catalyst; and addition of methanol to slurry phase FT synthesis making iso-olefins. During the seventh quarter we continued the shake down experiments for the SBCR and conducted an initial aborted run. We have also re-started experiments on Scheme 1, i.e., the addition of iso-butylene during CO hydrogenation. Using a dual bed arrangement, we have demonstrated the synthesis of MTBE from syngas and iso-butylene.

The objective of this project is to investigate three possible routes to the formation of ethers, in particular methyl tert-butyl ether (MTBE), during slurry phase Fischer-Tropsch reaction. The three reaction schemes to be investigated are: Addition of isobutylene during the formation of methanol and/or higher alcohols directly from CO and H{sub 2} during slurry-phase Fischer-Tropsch. Addition of isobutylene to FT liquid products including alcohols in a slurry-phase reactor containing an MTBE or other acid catalyst. Addition of methanol to slurry phase FT synthesis making iso-olefins.

The objective of this project is to investigate three possible routes to the formation of ethers, in particular methyl tert-butytl ether (MTBE), during slurry phase Fischer-Tropsch reaction. The three reaction schemes to be investigated are: (1) Addition of isobutylene during the formation of methanol and/or higher alcohols directly from CO and H{sub 2} during slurry-phase Fischer-Tropsch; (2) addition of isobutylene to FT liquid products including alcohols in a slurry-phase reactor containing an MTBE or other acid catalyst; and, (3) addition of methanol to slurry phase FT synthesis making iso-olefins.

Examination of the coupling reaction of methane in the gas-phase and over Pb–Mg–O catalysts reveals significant differences in certain kinetic parameters which are useful in determining the extent of homogeneous gas-phase contribution to the final product.

The preparation and characteristics of zirconium-modified alumina-aluminum phosphate were examined to determine their suitability as controlled-pore, catalytic supports. The composites were prepared by coprecipitation, at constant pH, of the metal ions using a mixture of ammonium phosphate and ammonium hydroxide as precipitating agents. Surface area and porosity were dependent upon the exact preparation parameters and were variable over a wide range. As the Al/Zr ratio increased, the materials exhibited the characteristic large surface area and porosity of alumina-aluminum phosphate. The surface properties also displayed a strong dependence upon the pH of precipitation with a higher pH resulting in a more rigid and, hence, less porous composite. Examination of the thermal stability of the supports by DTA and powder X-ray diffraction showed increased stability of the mixed phases over the pure components, with crystallization occurring only after 1000°C annealing. The resulting X-ray pattern obtained after high temperature annealing was related to the initial porosity of the materials.

The effect of ammonium bicarbonate as a precipitant upon the physicaln properties of activated alumina has been examined. The resulting precipitate is

The interaction of intercalated water molecules with Mg-Al-NO{sub 3} double-metal hydroxides has been studied by using NMR spectroscopy. The water molecules are hydrogen-bonded to the hydroxyl groups in the layers causing them to be oridented perpendicular to the plane of the layers, while retaining their translational mobility. The strength of the bonding between the interlayer water and the layers, as evidenced by the temperature at which a motionally averaged Pake doublet first appears, is related to the interlayer spacing available for intercalation of the guest water molecules.

Studies were conducted on the chemisorptive and magnetic properties of supported nickel catalysts in order to investigate the effect of metal-support interactions on different support materials. The catalysts consisted of both 7 and 20% nickel supported on SiO 2 , Al 2 O 3 , TiO 2 , alumina-aluminum phosphate (AAP), and magnesia-alumina-aluminum phosphate (MgAAP). For catalysts supported on phosphate-containing materials, the inducement of metal-support interactions was accompanied by both a lowering of the Curie temperature and a change in chemisorptive behavior. Irreversible hydrogen chemisorption was suppressed, as is typical of strong metal-support interactions (SMSI) materials, but a significant reversible chemisorption was still evident. In contrast, the inducement of SMSI in TiO 2 -supported catalysts showed no change in Curie temperature and no reversible hydrogen chemisorption. The different behaviors observed in the various materials have been attributed to different mechanisms responsible for the inducement of the metal-support interactions.

The oxidative dimerization of methane was studied over alkali-doped antimony oxide catalysts. Selectivities for C 2 hydrocarbons as high as 68% were achieved over 5% lithium-doped antimony oxide supported on SiO 2 . The addition of small amounts of alkali to supported antimony oxide was found to improve the selectivity for coupled products. However, the nature of the alkali (Li, K, or Cs) made little difference in the final catalytic properties. This increased selectivity is attributed to the scavenging, by the alkali species, of acidic sites on the support, which are believed to be total oxidation sites.

Magnetic studies were conducted on supported nickel catalysts in order to elucidate changes in the bulk structure of the ferromagnetic nickel upon high-temperature reduction and inducement of metal-support interactions. The catalysts consisted of 10% Ni Nb 2 O 5 , 9% Ni Nb 2 O 5 -SiO 2 , and both 7 and 20% Ni on modified aluminum phosphate (AP). Catalysts supported on AP exhibited a change from the normal magnetization-temperature behavior of bulk nickel when reduced at high temperatures. Higher temperature and longer reduction times were required to make this change apparent in the higher loading catalysts. Niobia-supported catalysts did not show any deviation from the normal magnetic behavior of bulk Ni, regardless of the reduction conditions. They did, however, exhibit an apparent loss of Ni metal and a decrease in crystallite size upon treatment at 600 °C for 16 h. The difference in magnetic behavior of Ni depending on the supports can be explained if one considers the Ni AP to interact through bulk alloy formation, but the Ni Nb 2 O 5 through an encapsulation-compound formation mechanism.

The nitrogen-containing aromatics normally found in crude retorted shale oils have been shown to be involved in reactions leading to the deposition of insoluble gums and sediments. These nitrogen-containing compounds must be removed in order to permit the effective utilization of the shale oil product. A process is proposed in which the nitrogen-containing compounds found in raw shale oil are removed by mild hydrodenitrogenation followed by resin ion exchange. Ion exchange data from experimentation involving six jet fuel (15M-271°C) and diesel fuel (271–343°C) boiling point cuts are presented. Amberlyst A-15, a macroreticular, strongly acidic, cation exchange resin is used in this study. Three types of experiments were performed: batch sorption equilibrium experiments, batch sorption kinetics experiments, and dynamic ion-exchange column performance tests. The Langmuir isotherm was found to describe the equilibrium sorption behavior of the shale oil/ion-exchange resin system fairly Well. The sorpt...

The kinetics of adsorption-desorption processes were measured using Frequency Response Chemisorption for CO on supported Rh catalysts. Measurements on Rh/SiO2 failed to give a signal, most likely due to the strong natures of the CO sorption on the metal. CO on Rh/TiO2 measurements indicated the existence of one molecularly adsorbed state. The rate constants for adsorption state were derived.

The surface area and pore properties of composites of magnesia-alumina-aluminum phosphate have been examined as a function of preparation parameters. Sufficiently good correlations were obtained between the composition and the BET surface area, average pore size and median pore size, so that empirical models could be constructed to predict these properties with a reasonable degree of confidence. Pore volume was found to be independent of composition. Other preparation variables, such as pH and calcination temperature, were examined and these were found to only slightly influence the characteristics of the finished product.