Microbiology, chemistry and biofilm development in a pilot drinking water distribution system with copper and plastic pipes

We studied the changes in water quality and formation of biofilms occurring in a pilot-scale water distribution system with two generally used pipe materials: copper and plastic (polyethylene, PE). The formation of biofilms with time was analysed as the number of total bacteria, heterotrophic plate counts and the concentration of ATP in biofilms. At the end of the experiment (after 308 days), microbial community structure, viable biomass and gram-negative bacterial biomass were analysed via lipid biomarkers (phospholipid fatty acids and lipopolysaccharide 3-hydroxy fatty acids), and the numbers of virus-like particles and total bacteria were enumerated by SYBR Green I staining. The formation of biofilm was slower in copper pipes than in the PE pipes, but after 200 days there was no difference in microbial numbers between the pipe materials. Copper ion led to lower microbial numbers in water during the first 200 days, but thereafter there were no differences between the two pipe materials. The number of virus-like particles was lower in biofilms and in outlet water from the copper pipes than PE pipes. Pipe material influenced also the microbial and gram-negative bacterial community structure in biofilms and water.     

On simplification of large fault trees

This paper describes some fault tree optimization algorithms used in STUK PSA code SPSA that is capable of generating minimal cut sets for fault trees containing 12 000 gates and basic events. The complexity of a minimal cut set search is a function of multiple gates and basic events. In a fault tree containing 1000 multiple elements, these optimizations reduce the number of multiple elements often by 30 to 50%. One novel feature of the algorithm is that no boolean reduction rules are used, since the fault tree itself contains its simplification rules.     

Significance of tissue anisotropy in optical tomography of the infant brain

We study the effect of tissue anisotropy in optical tomography of neonates. A Monte Carlo method capable of modeling photon migration in an arbitrary 3D tissue model with spatially varying optical properties and tissue anisotropy is used for simulating measurements of neonates. Anatomical and diffusion tensor magnetic resonance imaging of neonates are used for creating the anatomical models. We find that tissue anisotropy affects the measured signal and the pattern of sensitivity in optical measurements.     

The effect of low-intensity pulsed ultrasound on bone healing in SR-PLLA rod fixed experimental distal femur osteotomy in rat

The effects of low-intensity pulsed ultrasound (30 mW/cm²) were investigated in experimental cancellous bone fracture healing in bioabsorbable self-reinforced poly-l-lactide (SR-PLLA) rod fixed distal femur osteotomy in rats. A transverse transcondylar osteotomy was fixed with one SR-PLLA rod in 32 male Wistar rats of the age of 20 weeks. Half of the rats had a daily 20-min ultrasound exposure for three weeks. The follow-up times were three, six, and 12 weeks. Radiographical, histological, microradiographical, oxytetracycline labeling, and histomorphometrical analyses were performed. No foreign-body reactions were noted. The biocompatibility of SR-PLLA and ultrasound was found to be good. In the radiological and histological assessments there was a slight tendency for enhanced healing in the ultrasound group at three weeks, but at six and 12 weeks no differences were observed. The histomorphometrical and oxytetracycline labeling analyses showed that ultrasound exposure had no significant effects on bone healing. The present study shows that there were no obvious findings to support the hypothesis that low-intensity pulsed ultrasound enhances bone healing in self-reinforced poly-l-lactide (SR-PLLA) rod fixed experimental metaphyseal distal femur osteotomy in rats. The observed good biocompatibility provides a safe starting-point for clinical trials on bioabsorbable fixation combined with low-intensity ultrasound.     

Independent amplification and frequent co-amplification of three nonsyntenic regions on the long arm of chromosome 20 in human breast cancer

DNA amplification at 20q13.2 is common in breast cancer, correlates with poor prognosis, and may reflect location of an important oncogene. Recently, other regions along 20q were also found to undergo amplification. Here, amplification levels and patterns of co-amplification were analyzed by interphase fluorescence in situ hybridization at 14 loci along 20q in 146 uncultured breast carcinomas and 14 cell lines. Three regions were independently amplified in uncultured tumors: RMC20C001 region at 20q13.2 (highly amplified in 9.6% of the cases), PTPN1 region 3 Mb proximal (6.2%), and AIB3 region at 20q11 (6.2%). Co-amplifications involving two or three of these regions were seen in 11 of the 19 highly amplified tumors. The results suggest that three distinct nonsyntenic regions along 20q may be important and that complex chromosomal rearrangements underlie their frequent co-amplification in breast cancer.     

Dissolution properties of direcet compression tablets containing an agglomerated cellulose powder

In previous studies a novel agglomerated cellulose powder was shown to own advantageous properties for direct compression. Due to the favourable particle and powder properties this material has good binding and disintegration ability in direct compression tablets. In this study the dissolution properties of direct compression tablets containing the agglomerated cellulose powder as a fillerbinder were evaluated. Especially the effect of the amount of cellulose, the porosity of tablets, the solubility of drug material and the amount and the amount and mixing method of lubricant, magnesium stearate were studied.

Tablets containing different amounts of cellulose with dicalcium phosphate as a filler and 10 wt % of water soluble sodium tolmetin as a drug were compressed at a constant pressure of 150 MPa. The breaking strength of tablets increased with increasing amounts of agglomerated cellulose powder. However, the dissolution of drug accelerated up to cellulose amount of 50 wt %. This was due to the ability of the agglomerated cellulose powder to enhance the water penetration into powder compact and the loosening of tablet structure, i.e. formation of cracks.

Tablets containing 20 wt % of cellulose material and 10 wt % of drug material were compressed to different porosities. Tablet porosity had no effect on dissolution of poorly water soluble tolfenamic acid. Also the dissolution of water soluble sodium tolmetin was only slightly affected by the porosity of tablets. This supports the suggested disintegrant mechanism of the agglomerated cellulose powder. The expansion of cellulose agglomerates, which have been deformed, under compression, is widely responsible for the disintegration of the tablets. An increase in the amount as well as in the mixing intensity of magncsium stearate decreased the dissolution of sodium tolmetin from tablets containing 20 wt % of agglomerated cellulose. However, the intrinsic wetting and dissolution phenomens were practically unchanged when the amount of magnesium stearate was below 2 wt %. Thus, the retardation of drug dissolution was acceptable at low lubricant concentrations.

The properties of tablets containing the agglomerated cellulose were compared to those containing microcrystalline cellulose. In all cases tablets containing the agglomerated cellulose powder liberated drug clearly faster and more properly than corresponding microcrystalline cellulose tablets.     

Increased copy number at 17q22-q24 by CGH in breast cancer is due to high-level amplification of two separate regions

Our understanding of sodium transport defects has exploded in the past 18 months, and has provided unique insights into epithelial transport processes and unusual clinical syndromes resulting from mutations of specific transporters. These genetic disorders disturb sodium balance, with both sodium retaining and sodium wasting disorders as the consequence.     

Meta-searches in peer-to-peer networks

We propose a method for carrying out enhanced collaborative searches, called meta-searches, in peer-to-peer networks. In addition to performing regular searches, our method supports searches based on other network users’ previous searches on the same or similar topic. In essence, when a user performs a search, s/he will receive not only the usual result set, but also information on other users’ previous results, as well as relevancy information (such as how many times a resource that appeared in the result set was successfully downloaded). The core components of meta-search are query relevancy calculation, query matching algorithms, and relevancy file format. In this paper we discuss the underlying concepts and principles, and describe the component design in detail. Meta-search provides a way of benefiting from other users’ successful searches without any additional effort, thus potentially improving the efficiency and experience of a search.