[en] Short communication

[en] Particle track membranes (PTM) are ideal surface filters. Their parameters can be adjusted to the separation problem. In an investigation several RoTrac PTM with different pore parameters were tested in dead end filtration of microorganism suspensions. The used species were rod-like ''E. coli, Serratia marcescens, Pseudomonas diminuta'' with a rigid cell wall. The suitability of PTM in bacteria removal as well as in bacteria free filtration was proven. Blocking was very strong for membranes with pore diameters in size range of the microorganisms. Through the filtrate had immense reduced bacteria counts in these cases, it was generally not sterile. For the rigid bacteria type membranes with 0.2 μm and smaller pore diameters always assure a bacteria free filtrate even for a very high bacteria count of about 10⁷ to 10⁸ bacteria/ml. Flux (and thus the filterable volume) corresponds to values of competitive membranes. The filtration mechanism is governed by several processes. Both the membrane (pore diameter, shape, inclination, porosity) and the microorganisms (size, shape, count) have influence. (author). 13 refs, 7 figs, 1 tab

[en] Short communication. 2 refs, 2 figs

[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] A parametric particle track model for detector response to energetic heavy ions is described. (author)

[en] The results of tests for the track-reconstruction efficiency and the speed of the algorithm and its scalability with respect to the number of cores of the server with two Intel Xeon E5640 CPUs (in total 8 physical or 16 logical cores) are presented and discussed.

[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] Short communication. 2 refs, 5 figs