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Iron molybdate catalysts are used for the selective oxidation of methanol to formaldehyde. In this paper we have attempted to understand what determines high selectivity in this reaction system by doping haematite with surface layers of Mo by incipient wetness impregnation. This works well and the Mo appears to form finely dispersed layers. Even very low loadings of Mo have a marked effect on improving the selectivity to formaldehyde. Haematite itself is a very poor catalyst with high selectivity to combustion products, whereas, when only 0.25 monolayers of Mo are deposited on the surface, formaldehyde and CO selectivities are greatly enhanced and CO2 production is greatly diminished. However, even with as much as seven monolayers of Mo dosed on to the surface, these materials achieve much less selectivity to formaldehyde at high conversion than do the industrial catalysts. The reason for this is that the Mo forms a ‘skin’ of ferric molybdate on a core of iron oxide, but does not produce a pure Mo oxide monolayer on the surface, a situation which is essential for very high yields of formaldehyde. [ABSTRACT FROM AUTHOR]

The age of surface uplift in southeastern Tibet is currently unknown, but the initiation of major river incision can be used as a proxy for the timing of initial uplift. The topographically high eastern plateau and gently dipping southeastern plateau margin are mantled by an elevated, low-relief relict landscape that formed at a time of slow erosion at low elevation and low tectonic uplift rates prior to uplift of the eastern Tibetan Plateau. Thermochronology from deep river gorges that are cut into the relict landscape shows slow cooling between ca. 100 and ca. 10–20 Ma and a change to rapid cooling after ca. 13 Ma with initiation of rapid river incision at 0.25–0.5 mm/yr between 9 and 13 Ma. A rapid increase in mean elevation of eastern Tibet beginning at this time supports tectonic-climate models that correlate the lateral (eastern) expansion of high topography in Tibet with the late Miocene intensification of the Indian and east Asian monsoons. [ABSTRACT FROM AUTHOR]

We used a PC-based videoconferencing system to conduct child psychiatry assessments. The telecommunications link was six digital lines, giving a total bandwidth of 336 kbit/s. Twenty-three patients (aged 4-16 years), accompanied by their parents, completed two psychiatric assessments, one via videoconferencing and another face to face (FTF). The order of assessments was randomized. Questionnaires were used to record the diagnosis, treatment recommendations and the psychiatrists', patients' and their parents' satisfaction with each assessment. An independent evaluator concluded that in 22 cases (96%) the diagnosis and treatment recommendations made via the videoconferencing system were the same as those made FTF. The psychiatrists stated that videoconferencing assessments were an adequate alternative to FTF assessments and did not interfere with diagnosis. However, the responses from the psychiatrist satisfaction questionnaire showed that they preferred FTF assessments. No significant difference was found in the patients' or parents' satisfaction responses after the two types of assessment. The majority of children (82%) 'liked' using the telepsychiatry system and six (26%) preferred it to a FTF assessment. Most parents (91%) indicated that they would prefer to use the videoconferencing system than to travel a long distance to see a psychiatrist in person. [ABSTRACT FROM AUTHOR]

The use of renal artery Doppler ultrasound for the diagnosis of renal artery stenosis is a well-established technique in selected populations, but the technical failure rate of the examination leading to incomplete studies is a major drawback. The results of ultrasound contrast-enhanced renal artery Doppler for renal artery stenosis, using the echo-enhancing agent, Levovist, are reported here. Sixteen patients (22 arteries) were examined with Levovist. The technical success rate of these examinations was 91%, and all four renal artery stenoses were correctly identified. It is concluded that the use of ultrasound contrast (Levovist) increases the technical success rate of renal artery Doppler ultrasound in this setting, with similar accuracy to unenhanced Doppler examinations. [ABSTRACT FROM AUTHOR]

Bile duct varices are a rare manifestation of portal vein cavernous transformation. They can present as an apparent enhancing, vascular mass in the porta hepatis and are readily diagnosed using ultrasound and CT modalities. Diagnosis is important to avoid unnecessary intervention and concomitant risk of haemobilia. [ABSTRACT FROM AUTHOR]