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The successful correction of lens aberrations in scanning transmission electron microscopy has allowed an improvement in resolution by a factor of two in just a few years. The benefits for materials research are far greater than a factor of two might imply, because enhanced resolution also brings enhanced image contrast, and therefore a vast increase in sensitivity to single atoms, both for imaging and electron energy loss spectroscopy. In addition, aberration correction enables simultaneous, aberration-corrected, Z-contrast and phase contrast imaging, and brings a depth resolution at the nanometer level. It becomes possible to focus directly on features at different depths in the specimen thickness, and three-dimensional information can be extracted with single atom sensitivity. In conjunction with density functional and elasticity theory, these advances provide a new level of insight into the atomistic origins of materials properties. Several examples are discussed that illustrate the potential for applications, including the segregation of rare earth elements to grain boundaries in Si₃N₄ceramics, the quantitative analysis of strain-induced growth phenomena in semiconductor quantum wells, the explanation of the enhanced thermal stability of La-doped y-alumina as a catalyst support, and the origin of the remarkable catalytic activity of Au nanoparticles., Mercek hatalarının taramalı geçirimli elektron mikroskoplarında, son birkaç yıl içerisinde, başarılı bir şekilde düzeltilmesi, mikroskobun ayırma gücünde iki kat iyileşmeye olanak tanımıştır. Bu gelişmenin, malzeme araştırmalarına katkısı iki katın çok daha üzerinde olacaktır, çünkü iyileştirilmiş ayırım gücü, görüntü kontrastını iyileştirecek ve bundan dolayı da atomların tek atom hassaslığında görüntülenmesinin yanı sıra elektron enerji kaybı spektroskopisine de olanak tanıyacaktır. Buna ek olarak, düzeltme, Z-kontrast ve faz kontrast görüntülerinin aynı anda, nanometre düzeyinde, yüksek ayırma gücünde kullanılmasına olanak verir. Çeşitli derinliklerdeki numune kalınlıklarında, yapıların direkt üzerine odaklanılmasıyla, tek atom düzeyindeki algılamayla, üç boyutta bilgi elde edilmesi mümkündür. Yoğunluk fonksiyonu ve elastisite teorisinin beraber kullanımı, malzeme özelliklerinin atomik yapıya bakarak belirlenmesinde yepyeni ilerlemeler sağlar. Si₃N₄ seramiklerinin tane sınırlarında nadir toprak elementlerinin segregasyonunu, yarı iletken kuvantum kuyularında, gerinim giderilmiş büyüme olayını, katalist desteği olarak kullanılan La-doplu y-aluminanın geliştirilmiş termal kararlılığını ve nano boyutlu altın tanelerinin elle tutulur katalitik aktivitelerini de içeren bir çok uygulama alanı tartışılacaktır.

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The Infectious Diseases Surveillance Information system that collects data of medical microbiology laboratories in the Netherlands (ISIS-MML) is not suitable for early warning of infectious diseases outbreaks. However, the system is appropriate for monitoring trends in antimicrobial resistance. These are the main outcomes of an evaluation described in this report to evaluate technical problems and doubts about the performance and usefulness of the system. ISIS-MML was developed ten years ago by RIVM to provide current information on the occurrence of infectious diseases via Internet. Important goals were to observe outbreaks in time, prevent further spread of disease, and to limit the negative consequences of these outbreaks. For this purpose all 85 medical microbiology laboratories in the Netherlands had to send in data on a daily basis. The evaluation showed that only eighteen laboratories are connected to the system; this led to a lack of national coverage by the system, causing outbreaks to be missed. For example, the outbreak of Clostridium difficile-associated disease of ribotype 027 was missed in June 2005. Furthermore, the system regularly causes false alarms since not all increases in incidence of micro-organisms require control measures. That does not mean that ISIS-MML is useless and needs to be stopped. The system is the most important database for antimicrobial resistance in the Netherlands. The European Union strongly recommends surveillance of antimicrobial resistance since it an increasing problem. Therefore RIVM advises adaptation of the current system (in which hardware and software are outdated) to an antimicrobial surveillance system.

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This report presents the results of an inventory made in 2002 by the Dutch National Institute for Public Health and the Environment (RIVM) on the revisions of the EC Technical Guidance Documents (TGDs) in support of risk assessment for newly notified substances, existing substances and biocides. The TGDs (first published in 1996) were subject to an update procedure, taking into account the experience gained in the assessment of numerous new and existing substances and the additional needs of the risk assessment of biocides. The Competent Authorities (CAs) of the EU member states came to an agreement on the revised TGDs. The 'final draft' documents, available on August 1, 2002, on the protected European Chemicals Bureau (ECB) website were used for the current inventory. These documents remained unchanged until the finalisation of the current report in November 2002. RIVM risk assessments and risk assessment procedures, along with the software tool, EUSES (European Union System for the Evaluation of Substances), will be adapted on the basis of this report.

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Projectnr.: 06P012.

Contains fulltext : 56868.pdf (Publisher’s version ) (Closed access) 58 p.

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Contains fulltext : 56678.pdf (Publisher’s version ) (Closed access) 48 p.