RNA amplification chip with parallel microchannels and droplet positioning using capillary valves

We present results from the MicroActive project which develops an instrument for molecular diagnostics. The instrument is first tested for patient screening for a group of viruses causing cervical cancer. Two disposable polymer chips with reagents stored on-chip are developed and will be inserted into the instrument for each patient sample analysis. The first chip will perform nucleic acid extraction from patient epithelial cervical cells, while mRNA amplification and fluorescent detection takes place in the second chip. This paper reports results on the amplification chip. Purified sample is inserted into the chip and split into ten smaller droplets for simultaneous amplification and detection of ten viruses. The droplets move in parallel channels, each with two chamber extensions containing dried reagents. Experimental results on parallel droplet movement using one external pump combined with hydrophobic restrictions show that the parallel droplet positions can be controlled. There are four valves with increasing burst pressures between 800 and 4,500 Pa in each parallel channel, positioning the droplets in metering zones and reaction chambers. The re-hydration times for the dried reagents in micro chambers have been monitored. After sample insertion, uniform concentration of the reagents in the droplet was reached after respectively 60 s and 10 min. These times are acceptable for successful amplification. Finally we show positive amplification of HPV type 16 viruses in a micro chamber.     

Simulated Cryptosporidium removal under swimming pool filtration conditions

There has been no information available on the removal of Cryptosporidium oocysts or oocyst‐sized particles under the sand filtration conditions normally used for swimming pool water treatment. A pilot sand filtration plant has therefore been constructed at The University of Wales Swansea and operated under swimming pool conditions (25 m/h downflow, 30°C, 1.5 mg/L free chlorine, pH 7.3 to 7.5, alkalinity 120–150 mg/L as calcium carbonate). Removal of fluorescent polystyrene particles of a size range (1–7 μm) similar to the size of Cryptosporidium oocysts (about 5 μm) without added coagulant was less than 50%. Removal of the particles under the operating conditions above but with the addition of either of the coagulants polyaluminium chloride (PAC) or aluminium sulphate was capable of giving better than 99% removal of the particles.     

Exposure assessment of a burning ground for chemical ammunition on the Great War battlefields of Verdun

The destruction of arsenical shells from the 1914/18 war in the vicinity of Verdun (France) during the 1920s resulted in a locally limited but severe soil contamination by arsenic and heavy metals. At the study site, the main part of the contaminant inventory occurs in the upper 20 cm of the topsoil which is essentially composed of combustion residues. Besides, some Cu (cmax.=16,877 mg/kg) and Pb (cmax.=26,398 mg/kg) in this layer, As (cmax.=175,907 mg/kg) and Zn (cmax.=133,237 mg/kg) were detected in very high concentrations. The mobilities of Cu, Mn, Pb and Zn in the soil system were derived from ammonium nitrate eluates. They are strongly influenced by the soil pH and can be described by quadratic regression curves from which threshold pH values were calculated. Below these values more than 10% of the element content was available as mobile species. Within the examined pH range, this method could not be adopted for arsenic, because the mobility of As was only slightly controlled by the soil pH. In the heavily contaminated topsoil, Cu and Pb were fixed by the moderately acidic soil pH which varied from 4.8 to 5.8. No migration to the underlying horizons occurred. A different behavior was observed for As and Zn. The calculated threshold pH of Zn was 5.5, so certain amount of this element was transferred to the subsoil and the leachate (cmax.=350 microg/l). However, a major dispersion of Zn was prevented by a rise of the soil pH in the carbonate-containing subsoil. Elevated concentrations of As were found in all soil horizons up to a depth of 2 m and also in the leachate (cmax.=2377 microg/l). Contrary to Cu, Pb and Zn the mobility of As evidently was less affected by the subsoil. Regarding organic contaminants, nitroaromatic explosives were detected only in minor concentrations in the soil (cmax.=14.7 mg/kg) and the leachate (cmax.=13.5 microg/l). No aromatic organoarsenicals were detected in the soil and the leachate samples. The main hazard of the site is the severe arsenic contamination and the transfer of this carcinogen by leachate, surface runoff and probably by wind. Nevertheless, some studies on the effects of the contaminant inventory on the local vegetation revealed that ammonium nitrate elutable zinc is responsible for the spatial distribution of some tolerant plant species and not arsenic. Previously undetected buried munitions from the former delaboration facility can be an other source of environmental contaminants. This is supported by elevated concentrations of chlorate (cmax.=71 mg/l) and perchlorate (cmax.=0.8 mg/l) detected in the leachate samples. This is the second report about environmental contamination related to post-war ammunition destruction activities along the 1914/18 Western Front.     

Development of a robust laser beam bending process for aluminum fuselage structures

The aeronautic industry has to face the demand of cost reduction by its customers. These costs are divided into acquisition and operating costs. Both can be reduced by optimization and automation of production steps and by using highly integrated light weight structures. Within the EU-founded FP 6 project ECOSHAPE a laser beam forming (LBF) process for the laser beam bending of complex fuselage aluminum panels has been developed. The aim was to build up the fundamental know-how for an industrial manufacturing process performing most production steps in flat condition due to a minimum of machining costs, technological complexity and a maximum of robustness and reliability. To facilitate the cost intensive qualification of the LBF-process the metallurgical behavior of the aluminum alloys is investigated as well as the influences of the single structural elements of the fuselage panels like stingers and pockets on the forming result. For the industrial upgrade the process is integrated into a discrete control loop using the geometry of the panel as control variable.     

节假日期间面临的安全保护挑战

当重要的节日（如中国的春节和西方的圣诞节）到来之时,许多机构组织的大部分员工都休假了,业务通常在一段时间内完全停止,或最多只留下极少数员工来为其顾客提供服务。在欢庆的节假日里网络攻击者却不放假,因此对安全不能放松警惕。     

Local-Line Single-Mode Optics--Viable Options for Today and Tomorrow

Introducing optical transmission into the local network poses a number of severe economic and technological problems. In this paper, we address these problems assuming a future requirement for a wholly monomode transmission network through long/short haul and local lines. The key considerations therefore involve the economic realization of systems in the 2-140 Mbit/s range. Specific laboratory designs at 2, 8, and 34 Mbits/s employing uni- and bidirectional operation are discussed. Field experience at 1.3 and 1.5 μm using very low cost unidirectional and bidirectional systems is reported, including systems based upon directional couplers, wavelength-duplex, and "piggyback" schemes.     

Studies on a toxic metabolite from the mould Wallemia

While monitoring the occurrence of toxigenic moulds in foods, using a bioassay screen, it was shown that an isolate of Wallemia sebi produced toxic effects in several of the bioassays. The toxic metabolite was isolated and purified using solvent extraction, TLC and HPLC coupled with the brine shrimp assay to monitor the toxic fractions. The purified toxin, which we propose to call walleminol A, has been partially characterized by mass spectroscopy, nuclear magnetic resonance, ultraviolet and infrared spectroscopy. It can be provisionally interpreted as a tricyclic dihydroxy compound, C15H24O2, with structural features characteristic of a sesquiterpene with an isolated double bond, but further work is required to characterize this compound unequivocally. The minimum inhibitory dose of walleminol A in the bioassays is approximately 50 micrograms/ml, which is comparable with a number of mycotoxins such as citrinin and penicillic acid.