In-situ diagnostic of femtosecond laser probe pulses for high resolution ultrafast imaging

Ultrafast imaging is essential in physics and chemistry to investigate the femtosecond dynamics of nonuniform samples or of phenomena with strong spatial variat...     

浅议高层办公建筑的发展

当今高层办公建筑挣脱了20世纪50～60年代“方盒子”的束缚,走向了丰富多变的平面及形体设计时期。转向关注节能设计、创造多元的人性化公共空间及舒适的办公环境,成为设计的目标。     

The alpha-to-beta conformational transition of Alzheimer's Abeta-(1-42) peptide in aqueous media is reversible: a step by step conformational analysis suggests the location of beta conformation seeding

Current views of the role of beta-amyloid (Abeta) peptide fibrils range from regarding them as the cause of Alzheimer's pathology to having a protective function. In the last few years, it has also been suggested that soluble oligomers might be the most important toxic species. In all cases, the study of the conformational properties of Abeta peptides in soluble form constitutes a basic approach to the design of molecules with "antiamyloid" activity. We have experimentally investigated the conformational path that can lead the Abeta-(1-42) peptide from the native state, which is represented by an alpha helix embedded in the membrane, to the final state in the amyloid fibrils, which is characterized by beta-sheet structures. The conformational steps were monitored by using CD and NMR spectroscopy in media of varying polarities. This was achieved by changing the composition of water and hexafluoroisopropanol (HFIP). In the presence of HFIP, beta conformations can be observed in solutions that have very high water content (up to 99 % water; v/v). These can be turned back to alpha helices simply by adding the appropriate amount of HFIP. The transition of Abeta-(1-42) from alpha to beta conformations occurs when the amount of water is higher than 80 % (v/v). The NMR structure solved in HFIP/H2O with high water content showed that, on going from very apolar to polar environments, the long N-terminal helix is essentially retained, whereas the shorter C-terminal helix is lost. The complete conformational path was investigated in detail with the aid of molecular-dynamics simulations in explicit solvent, which led to the localization of residues that might seed beta conformations. The structures obtained might help to find regions that are more affected by environmental conditions in vivo. This could in turn aid the design of molecules able to inhibit fibril deposition or revert oligomerization processes.     

A Threat Analysis of Human Bond Communications

In this paper we provide a high-level threat analysis of Human Bond Communications, using the STRIDE methodology. To this end, we provide an overview over Human Bond Communications and define a sample set of cases. The Human Bond Communications cases are such that the threats literally may be existential by nature. We also outline the STRIDE threat analysis methodology, and apply it to the sample set of cases previously defined. The threat analysis is carried out at a high abstraction level to highlight the major threats.

     

Standpunkte, Praktiken und Kenntnisstand zur Ferkelkastration in Europa (PIGCAS) – Projektziele und erste Ergebnisse

Most of the male piglets in the EU are castrated. According to the current EU legislation, surgical castration can be performed without anaesthesia up to the age of 7 days. A report of the European Food Safety Authority (EFSA) on the welfare aspects in relation to the castration of pigs has underlined the need for further research. As a follow up, the EU has launched a two-year project (Specific Support Action PIGCAS) within the 6^th EU Framework Programme, starting in January 2007. “PIGCAS” is the acronym for “Attitudes, practices and state of the art regarding piglet castration in Europe”. The main objectives are: [A] to collect information on the attitudes of the various stakeholders (consumer groups, NGOs and industry stakeholders); [B] to collect information on the extent of the practice of castration of piglets (male or female) within the EU and the conditions under which castration is performed; [C] to evaluate research work and other sources of information, in order to examine surgical castration without anaesthesia and its possible alternatives from different perspectives and derive research priorities; and [D] to integrate the collected information and evaluation in a report providing support for EU policy in the field of research and legislation. Preliminary results are now available on objectives [A] and [B]. When referring to the alternatives to surgical castration, one has to distinguish between short-term and long-term solutions. Surgical castration with anaesthesia was mentioned by most of the stakeholders as a short-term alternative. Genetic control of boar taint and sperm sexing to select only females for pork production are considered as long-term alternatives. Current practices of castration and levels of acceptability vary substantially between and within countries and regions. The current research focuses on practical methods for acute and postoperative pain alleviation and analyses the complex consequences of raising entire males or immunocastrated boars. Considering the different dimensions (attitudes, extent of practice, animal welfare, pork quality and economy) of importance, it is intended to propose to the EU short and long-term strategies to handle this problem.

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Eingegangen: 26. Februar 2008; angenommen: 29. Februar 2008     

Biodegradable Frequency‐Selective Magnesium Radio‐Frequency Microresonators for Transient Biomedical Implants

Bioresorbable implantable medical devices show a great potential for applications requiring medical care over well‐defined periods of time. Once their function is fulfilled, such implants naturally degrade and resorb in the body, which eliminates adverse long‐term effects or the need for a secondary surgery to extract the implanted device. Since biodegradable materials are water‐soluble, the fabrication of such transient electronic circuits and devices requires special care and needs to rely solely on dry processing steps without exposure to aqueous solutions. A further challenge is the in vivo powering of medical implants that are only constituted of biodegradable materials. This paper describes the design, fabrication, and testing of radio‐frequency biodegradable magnesium microresonators. To this end, an innovative microfabrication process with minimal exposure to aqueous media is developed to fabricate magnesium‐based, water‐soluble electronic components. It consists of a novel sequence of only three steps: one physical vapor deposition, one photolithography, and one ion beam etching step. The frequency‐selective wireless heating of different resonators is demonstrated. This represents a significant step toward their use as power receivers and microheaters in biodegradable implantable medical devices, for applications such as triggered drug release.     

Modeling the longitudinal variation of sawn timber grades in Norway spruce (Picea abies (L.) Karst.)

Grades derived from visual assessments of sawn timber are determined by the worst part of each piece. Since grade varies longitudinally in timber, grade yield will decrease if the average length of timber increases. The variation in grade is caused by longitudinal variation in knot properties and other features as they appear on the sawn surface taken into account during grading. The objective of this study is to describe and analyze this variation in Picea abies. The study consisting of 768 boards for which all features that could lead to downgrading were recorded noting position, type and size. Based on this information, all boards were graded according to appearance by Nordic Timber, and strength by INSTA 142. Logistic regression models of grade as a function of position in the stem were developed, and the dependence between responses was taken into consideration by using General Estimating Equations (GEE). The models showed a decreasing trend in grade from the butt end toward the top end of the trees, and the effect was more pronounced in strength grading than in appearance grading. Models with binomial response and different correlation structures were tested, and it was shown that both independent and autoregressive correlation structures could be used. This suggests that a multinomial ordinal logistic regression with a GEE-approach with an independent correlation structure is appropriate for modeling grade in this study.     

Designing an electricity tax system in presence of international regulations and multiple public goals: An empirical assessment

The European competition rules restrict governments’ opportunity to differentiate terms of energy accessibility among firms and industries. This easily runs counter with regional and industrial goals of national energy policies. Norway levies a tax on use of electricity, but exempts main industrial usages. This analysis assesses alternative, internationally legal, designs of the system in terms of their effects on efficiency and distribution, including industrial objectives. Among the reforms we explore, removing the exemptions would be the most effective way of raising revenue, but it would be politically costly by deteriorating the competitiveness of today's favoured industries. An entire abolishment of the electricity tax, and replacing revenue by increased VAT, would generate a more equal distribution of standard of living and, at the same time, avoid the trade-off between efficiency and competitiveness.     

Bioinformatics — Mining the genome for information

Since the launching of the human genome sequencing project in the 1990s, genomic research has already achieved definite results. At the beginning of the present century, the complete genomes of several model organisms have already been sequenced, including a number of prokaryote microorganisms and the eukaryotes yeast (Saccharomyces cerevisiae), nematode (C. elegans), fruit fly (Drosophila melanogaster) and thale cress (Arabidopsis thaliana) as well as the major part of the human genome. These achievements signified that a new era of data mining and analysis on the human genome had commenced. The language of human genetics would gradually be read and understood, and the genetic information underlying metabolism, development, differentiation and evolution would progressively become known to mankind. Large amounts of data are already accumulating, but at present many of the rules that should guide the understanding of this information are yet unknown. Bioinformatics research is thus not only becoming more important, but is also faced with severe challenges as well as great opportunities.