Extracorporeal membrane oxygenator support for cardiopulmonary failure. Experience in 28 cases

We have used extracorporeal membrane oxygenation (ECMO) for 28 patients (14 children and 14 adults) over a 5 year period. Nine patients improved on ECMO and 5 were long-term survivors. ECMO was used for pulmonary insufficiency in 24 patients. Initially, only moribund patients were treated, but recently the combination of open lung biopsy and pulmonary insufficiency index (PII) has been used to select patients. The best results have been obtained in newborn cases and the adult capillary leak syndromes; the major problem has been progression to fibrosis despite ECMO support. ECMO was used for cardiac failure in 4 patients. Children with postoperative cardiac failure did the best; profound shock was not reversed with venoarterial bypass. ECMO support is lifesaving in selected cases of pulmonary insufficiency. Initial trials in cardiac failure and the infant age group in this series suggest that ECMO will have an even greater role in those applications.     

Radar image texture as a function of forest stand age

Data on forest variables are required for environmental and forest management applications. Numerous authors have shown significant correlations between mean radar response intensity and forest variables (age, height or biomass) but few studies have explored the spatial characteristics of the radar response for varying forest states. In this Letter, variation in the most commonly used texture features is shown as a function of an indicator of forest growth (age) for a controlled homogeneous test site (monospecific, even‐aged forest, with identical sylvicultural practices and a sampling that covers all forest stages from sowing to harvest). Significant linear relationships between some texture features and stand age are observed. Moreover, the quality of some fits indicates that texture could be used instead of the usual intensity–age relationships that saturate for mature stands.     

Structure and stability of an immunoglobulin superfamily domain from twitchin, a muscle protein of the nematode Caenorhabditis elegans

The NMR solution structure of an immunoglobulin superfamily module of twitchin (Ig 18') has been determined and the kinetic and equilibrium folding behaviour characterised. Thirty molecular coordinates were calculated using a hybrid distance geometry-simulated annealing protocol based on 1207 distance and 48 dihedral restraints. The atomic rms distributions about the mean coordinate for the ensemble of structures is 0.55( +/- 0.09) A for backbone atoms and 1.10( +/- 0.08) A for all heavy atoms. The protein has a topology very similar to that of telokin and the titin Ig domains and thus it falls into the I set of the immunoglobulin superfamily. The close agreement between the predicted and observed structures of Ig 18' demonstrates clearly that the I set profile can be applied in the structure prediction of immunoglobulin-like domains of diverse modular proteins. Folding studies reveal that the protein has relatively low thermodynamic stability, deltaG(H2O)U-F = 4.0 kcal mol(-1) at physiological pH. Unfolding studies suggest that the protein has considerable kinetic stability, the half life of the unfolding is greater than 40 minutes in the absence of denaturant.     

The anthropogenic nitrogen cycle in the Netherlands

Results of a study on the nitrogen flows in the Netherlands are presented for three different years. The details given for 1995 are preliminary. The data are derived from a material balance sheet investigation. The objective of the study is to present a complete, integrated and accurate overview of nitrogen losses from the anthropogenic nitrogen cycle in the country with respect to present and possible future nitrous oxide emissions. Losses are analyzed in terms of economic sources and the recipient environmental compartments. The nitrogen losses account for about 25% of the total nitrogen input in the anthropogenic nitrogen cycle. Most of the losses occur in agriculture (67%), whereas industry, traffic and households each contribute about 10% to the total nitrogen loss. About 15% of the total nitrogen input in the national economy ends up in the environment, where it gives rise to adverse effects as the eutrophication of fresh surface water and the contamination of ground water with nitrate. A comparison of the results for different years shows that little progress has been made in emission reductions so far. Ammonia emissions have been reduced, but at the expense of an increase of the nitrogen input to agricultural soils.     

On the mechanism of enhancing the nucleation behavior of UNCD films by Mo-coating

Enhanced nucleation behavior for ultra-nanocrystalline diamond on Si-substrates via the utilization of Mo-coating was observed. Spectroscopic examinations indicated that the mechanism of enhancement is the formation of Mo₂C phase, which hindered the inward diffusion of carbon species into the substrate materials. The diamonds may either nucleate directly on Mo₂C-layer or via the formation of transition phases, the graphite. The incoming carbons may also react with Mo₂C phase to form MoC phase or form the graphite phase prior to the induction of diamond nuclei. In all cases, the carbons accumulated rapidly due the presence of a Mo₂C (or MoC) layer, triggering the formation of diamond nuclei.     

电动旋转定位机设计与分析

介绍一种旋转定位机的工作原理，分析了定位机的分度精度和传动力矩计算，建立了完整的设计准则，为定位机的正确使用和设计开发提供了理论根据．