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[en] A modified CR-39 microfilter with funnel-shaped pore entrances is produced by using a multi-step etching procedure with NaOH and PEWsub(x) solution (PEWsub(x) = 15g KOH + x g C2H5OH + (85 - x)g H2O) as etching agents. The air throughput through this microfilter is measured and compared with the CR-39 microfilter with cylinder-shaped pores and a commercial microfilter (Nuclepore). The experimental data of both CR-39 microfilters show a good agreement with the theoretical values for the air throughout contrary to the Nuclepore microfilter. Furthermore both CR-39 filters have an extremely plane surfaces and no roughness of the pore walls. (author)
[en] Present-day microtechnology depends very much on the availability of suitable lithographic techniques for generating smaller and smaller structures. On this road, conventional techniques using light particles, such as photons or electrons, are approaching their technological limits. Our goal is to scrutinize the technique of ion track generation in order to extract technologically relevant properties and predict potential fields of future applications. Examples of practical relevance are given. (author)
[en] A study has been carried out on the filtration of bacteria having different shapes and sizes using particle track microfilters. The filtration of spherical shaped bacteria (staphylococci), rod-like bacteria (colon bacilli) and mixed miscellaneous bacteria living in pool water in the countryside shows quantitatively that particle track microfilters are a reliable tool to remove various bacteria from liquid substances. The study convinces us that in future particle track microfilters will play an important role in medical sciences and daily life. (author)
[en] Hydrophobicity is known to play a key role in the biological distribution of materials but is often an overlooked parameter when conjugating targeting agents, drugs, and dyes to dendrimers. This review examines the impact of hydrophobic variation in stochastically conjugated dendrimers as well as materials where synthetic methods or approaches to purification provide more controlled samples. Hydrophobic interactions are considered for three general classes: (1) terminal functional group modifications, (2) bioactive small molecules chosen to interact with receptors and proteins as targeting agents and/or drugs, and (3) imaging agents to track biological activity. Impacts on membrane interaction and cellular uptake, biodistribution, interaction with transport proteins, and pharmacokinetics are discussed. The size range of the dendrimers discussed is ~ 1–10 nm.
[en] The 15-Foot Bubble Chamber was exposed to a wide-band neutrino beam from the Fermilab Tevatron. A large number of photographs was taken simultaneously in a holographic setup and with conventional cameras. Technical aspects of this experiment will be discussed. (orig.)
[en] Spatial stochastic molecular simulations in biology are limited by the intense computation required to track molecules in space either in a discrete time or discrete space framework, which has led to the development of parallel methods that can take advantage of the power of modern supercomputers in recent years. We systematically test suggested components of stochastic reaction-diffusion operator splitting in the literature and discuss their effects on accuracy. We introduce an operator splitting implementation for irregular meshes that enhances accuracy with minimal performance cost. We test a range of models in small-scale MPI simulations from simple diffusion models to realistic biological models and find that multi-dimensional geometry partitioning is an important consideration for optimum performance. We demonstrate performance gains of 1-3 orders of magnitude in the parallel implementation, with peak performance strongly dependent on model specification.
[en] It is only recently that solid state nuclear track detectors (SSNTD) have started to spread to research centres. Its wide scope of applications and simple setting will, no doubt, cause it to be put a greater number of uses. They have only just started to be used in Latin America and are little known in this area. With this review we have endeavoured to give the information lacking, particularly since no complete literature on the subject is available in Spanish. We have presented a brief summary of the basic theory, processes, methods and applications of (SSNTD), a thorough search in the literature of the last five years has been performed and the previous most relevant information has also been included