The effect of gold loading and particle size on photocatalytic hydrogen production from ethanol over Au/TiO2 nanoparticles.

Catalytic hydrogen production from renewables is a promising method for providing energy carriers in the near future. Photocatalysts capable of promoting this reaction are often composed of noble metal nanoparticles deposited on a semiconductor. The most promising semiconductor at present is TiO2. The successful design of these catalysts relies on a thorough understanding of the role of the noble metal particle size and the TiO2 polymorph. Here we demonstrate that Au particles in the size range 3-30 nm on TiO2 are very active in hydrogen production from ethanol. It was found that Au particles of similar size on anatase nanoparticles delivered a rate two orders of magnitude higher than that recorded for Au on rutile nanoparticles. Surprisingly, it was also found that Au particle size does not affect the photoreaction rate over the 3-12 nm range. The high hydrogen yield observed makes these catalysts promising materials for solar conversion.

Synthesis of novel magnetic iron metal-silica (Fe-SBA-15) and magnetite-silica (Fe(3)O(4)-SBA-15) nanocomposites with a high iron content using temperature-programed reduction.

Magnetic iron metal-silica and magnetite-silica nanocomposites have been prepared via temperature-programed reduction (TPR) of an iron oxide-SBA-15 (SBA: Santa Barbara Amorphous) composite. TPR of the starting SBA-15 supported Fe(2)O(3) generated Fe(3)O(4) and FeO as stepwise intermediates in the ultimate formation of Fe-SBA-15. The composite materials have been characterized by means of x-ray diffraction, high resolution transmission electron microscopy and SQUID (superconducting quantum interference device) magnetometry. The Fe oxide and metal components form a core, as nanoscale particles, that is entrapped in the SBA-15 pore network. Fe(3)O(4)-SBA-15 and Fe-SBA-15 exhibited superparamagnetic properties with a total magnetization value of 17 emu g(-1). The magnetite-silica composite (at an Fe(3)O(4) loading of 30% w/w) delivered a magnetization that exceeded values reported in the literature or obtained with commercial samples. Due to the high pore volume of the mesoporous template, the magnetite content can be increased to 83% w/w with a further enhancement of magnetization.

Reverse engineering of metabolic pathways from observed data using genetic programming.

Recent work has demonstrated that genetic programming is capable of automatically creating complex networks (such as analog electrical circuits and controllers) whose behavior is modeled by linear and non-linear continuous-time differential equations and whose behavior matches prespecified output values. The concentrations of substances participating in networks of chemical reactions are also modeled by non-linear continuous-time differential equations. This paper demonstrates that it is possible to automatically create (reverse engineer) a network of chemical reactions from observed time-domain data. Genetic programming starts with observed time-domain concentrations of input substances and automatically creates both the topology of the network of chemical reactions and the rates of each reaction within the network such that the concentration of the final product of the automatically created network matches the observed time-domain data. Specifically, genetic programming automatically created metabolic pathways involved in the phospholipid cycle and the synthesis and degradation of ketone bodies.

Filamentous carbon growth on nickel/silica: potassium and bromine as catalyst promotors.

In a previous Communication, we reported the catalytic growth of highly ordered carbon filaments during the hydrodechlorination of chlorobenzene over nickel/silica at the remarkably low temperature of 553 K. This low temperature growth was attributed to the presence of bromine and potassium on the catalyst surface, which facilitated a restructuring of the active sites leading to a destructive chemisorption of the reactant that preceded the dissolution and precipitation of carbon in an ordered fashion. In this paper, we examine the effect of bromine and potassium built into (by impregnation with KOH, HBr and KBr) a Ni/SiO2 parent sample on filamentous carbon production through ethylene decomposition. The parent catalyst delivered a low yield of carbon (0.2 g(C)g(cat)(-1)) and promoted the competing hydrogenation (to ethane) step to the same degree; hydrogenolysis to methane represented the only other significant reaction. The nature of the carbon deposition has been characterised by high-resolution transmission electron microscopy (HRTEM) and temperature-programmed oxidation (TPO). Impregnation with KOH resulted in little change in carbon yield but the hydrogenolysis step was completely suppressed. A combination of CO chemisorption/temperature programmed desorption has been employed to probe the electronic structure of the nickel sites where the presence of potassium limited CO uptake in contrast to surface bromine which served, through electron withdrawal, to strengthen the CO-Ni interaction. Incorporation of bromine into the catalyst resulted in a marked increase in nickel particle size and a dramatic enhancement of carbon yield; the sample treated with KBr delivered the appreciably higher carbon yield of 7.6 g(C)g(cat)(-1)). While the presence of bromine on the surface served to enhance carbon deposition, the additional incorporation of potassium raised the degree of order in the carbon growth.

Anhydride modified cantharidin analogues. Is ring opening important in the inhibition of protein phosphatase 2A?

A series of anhydride modified cantharidin analogues have been synthesised and screened for their ability to inhibit protein phosphatase 2A. Surprisingly only analogues capable of undergoing a facile ring opening of the anhydride moiety displayed any significant inhibition. Subsequent NMR experiments indicated that 7-oxobicyclo[2.2.1]heptane-2,3-dicarboxylic acid was the major (sole) species under assay conditions. The ability of these modified anhydro-cantharidin analogues to inhibit protein phosphatase 2A varies from 4 (16) to 100% (8) at 100 microM test concentration.

Detoxifying chlorine rich gas streams using solid supported nickel catalysts.

Catalytic hydrogen treatment is presented as a viable low energy means of treating/detoxifying concentrated chlorinated gas streams to generate recyclable raw materials. Nickel (1.5% w/w and 15.2%) loaded silica and nickel (2.2% w/w) exchanged Y zeolite catalysts have been used to hydrotreat a range of chlorophenols (CPs), dichlorophenols (DCPs), trichlorophenols (TCPs) and pentachlorophenol (PCP) over the temperature interval 473 K

A histological basis for the 'sonographic snowstorm' in opportunistic infection of the liver and spleen.

We report 3 cases of opportunistic infection of the liver and spleen due to Pneumocystis carinii, Candida albicans and Aspergillus with an unusual but similar sonographic appearance. In the patient with Pneumocystis we report for the first time this same appearance in the bowel and pleura. Histology showed either extensive fibrosis or focal fibrinous exudates as the underlying cause. Calcification, though present, was scanty and was not thought to be the likely explanation for the appearances.

Institutional Review Board (IRB) review lacks impact on the readability of consent forms for research.

Consent forms in research are a source of current and retrospective information for the subject, a "prompt" for the person who is obtaining consent, and a documentation of the "informed" consent process and its adequacy. Occasionally, these forms may be administered by inexperienced trainees or ancillary personnel, and thus stand virtually alone. Therefore, the forms must be inherently comprehensible to the subjects. To test whether this is the case, 65 new applications were randomly selected from 13 consecutive IRB agendas, and their consent documents were computer-analyzed (Flesch/Fry scoring) after correction for expected confounding features, such as lists, tables, and polysyllabic proper names and jargon. Mean U.S. school grade for 70% comprehension (Fry score) was 15.03 +/- 0.19 (standard error of the mean), implying readability by 37.4 +/- 1% of the U.S. adult population. In contrast, a consecutive sampling of 21 Ann Landers columns yielded a mean Fry score of 7.67 +/- 0.5 (p < 0.01; readable by 75 +/- 3%). Fifteen Reader's Digest articles yielded a mean Fry score of 9.95 +/- 0.65 (p < 0.01; readable by 59.1 +/- 3%), and 15 "Talk of the Town" columns from The New Yorker averaged a grade level of 13.3 +/- 0.83; p < 0.01; readable by 42.7% +/- 4.8%). No document was improved by more than one grade level by the IRB review process, and most were unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetics and effects on blood pressure of a single oral dose of milrinone in healthy subjects and in patients with renal impairment.

Milrinone, a new, nonglycosidic inotropic agent with peripheral vasodilating properties, was given as a single oral 5 mg dose to 7 healthy subjects, 7 patients with moderate renal impairment (CRI I, creatinine clearance 30-63 ml/min) and 7 patients with severe renal impairment had hypertension. The mean urinary recovery of milrinone was 82% in healthy subjects, the renal clearance was 288 ml/min and the plasma half-life (t1/2) was 0.94 h. In CRI the mean plasma t1/2 was prolonged (CRI I 1.78 h, CRI II 3.24 h). There was a significant linear relationship between creatinine clearance and the elimination rate constant, and between creatinine clearance and the renal clearance of milrinone. During the study day there was a tendency to a decrease in supine BP from 1 to 6-8 h after dosing, with the maximal decrease at 2-3 h (healthy subjects 118/71----107/56, CRI 159/95----136/79 mmHg). The same degree of change was seen in standing BP. A slight rise in standing HR was seen from 2-6 h after dosing. Changes in BP and HR are difficult to evaluate since the study was not placebo-controlled. The plasma elimination rate of milrinone was decreased in CRI and dose adjustment may be necessary. Placebo-controlled studies of milrinone in hypertensive patients would be required to validate its possible antihypertensive effect.

The effects of prolonged hepatic ischaemia before 70 per cent partial hepatectomy in the dog.

The effect of prolonged normothermic ischaemia before partial hepatectomy was assessed in 10 dogs. During the period of ischaemia, portal decompression was maintained. The survival rate for animals undergoing 75 minutes of total liver ischaemia was 60 per cent and 2 of the dogs died as a result of hypoglycaemia. High levels of alkaline phosphatase and transaminases in the survivors indicated a severe degree of hepatocyte damage. However, complete restoration of liver mass was noted 6 weeks after partial hepatectomy and was not impaired by the prolonged ischaemia. This study confirms the resistance of the dog liver to ischaemia before partial hepatectomy. The critical period beyond which ischaemia is followed by an increasing number of deaths and severe metabolic upset is in the region of 1 hours.

The effect of hepatic ischaemia on liver function and the restoration of liver mass after 70 per cent partial hepatectomy in the dog.

Partial hepatectomy was performed in dogs either as the only procedure or following a period of ischaemia of liver remnant produced by inflow occlusion for periods of 30-60 minutes before partial hepatectomy. Temporary portal decompression was maintained through the portion of liver subsequently excised. 1. Survival in dogs subjected to partial hepatectomy and ischaemia to the liver remnant was similar to that in animals after partial hepatectomy alone. 2. Metabolic changes were similar in both groups but dogs submitted to partial hepatectomy and ischaemia to the remnant had higher serum alkaline phosphatase and alanine amino-transferase levels with increased bromsulphthalein in the fourth to sixth post-operative weeks. 3. Replacement of liver mass proceeded rapidly in all groups of animals. It is concluded that ischaemia of the liver remnant for up to 60 minutes preceding partial hepatectomy in the dog is consistent with survival and produced little change in postoperative liver function or in the rate of restoration of liver mass.