Four different approaches for the measurement of IC surface temperature: application to thermal testing

Silicon die surface temperature can be used to monitor the health state of digital and analogue integrated circuits (IC). In the present paper, four different sensing techniques: scanning thermal microscope, laser reflectometer, laser interferometer and electronic built-in differential temperature sensors are used to measure the temperature at the surface of the same IC containing heat sources (hot spots) that behave as faulty digital gates. The goal of the paper is to describe the techniques as well as to present the performances of these sensing methods for the detection and localisation of hot spots in an IC.     

Improved Approximation Results for the Minimum Energy Broadcasting Problem

In this paper we present new results on the performance of the Minimum Spanning Tree heuristic for the Minimum Energy Broadcast Routing (MEBR) problem. We first prove that, for any number of dimensions d≥2, the approximation ratio of the heuristic does not increase when the power attenuation coefficient α, that is the exponent to which the coverage distance must be raised to give the emission power, grows. Moreover, we show that, for any fixed instance, as a limit for α going to infinity, the ratio tends to the lower bound of Clementi et al. (Proceedings of the 18th annual symposium on theoretical aspects of computer science (STACS), pp. 121–131, 2001), Wan et al. (Wirel. Netw. 8(6):607–617, 2002) given by the d-dimensional kissing number, thus closing the existing gap between the upper and the lower bound. We then introduce a new analysis allowing to establish a 7.45-approximation ratio for the 2-dimensional case, thus significantly decreasing the previously known 12 upper bound (Wan et al. in Wirel. Netw. 8(6):607–617, 2002) (actually corrected to 12.15 in Klasing et al. (Proceedings of the 3rd IFIP-TC6 international networking conference, pp. 866–877, 2004)). Finally, we extend our analysis to any number of dimensions d≥2 and any α≥d, obtaining a general approximation ratio of 3 ^d −1, again independent of α. The improvements of the approximation ratios are specifically significant in comparison with the lower bounds given by the kissing numbers, as these grow at least exponentially with respect to d. The research was partially funded by the European project COST Action 293, “Graphs and Algorithms in Communication Networks” (GRAAL). Preliminary version of this paper appeared in Flammini et al. (Proceedings of ACM joint workshop on foundations of mobile computing (DIALM-POMC), pp. 85–91, 2004).     

Aerobic spore-forming bacteria for assessing quality of drinking water produced from surface water

Cryptosporidium and Giardia represent a major microbiological issue for drinking water production from surface water. As their monitoring through a treatment process is rather tedious and as low-concentration goals should be reached for drinking water, aerobic spore-forming bacteria (ASFB) have been studied as an indicator microorganism for a drinking water treatment plant using surface water. The results reveal that monitoring naturally occurring ASFB better highlights daily achievable performances and identifies unusual process events for global disinfection, for both physical and chemical treatment steps in a multi-barrier drinking water treatment plant. Advantages of ASFB over usual process parameters are that these microorganisms are more sensitive to process fluctuations.

The use of ASFB also showed that the efficiency of ozone disinfection is not as significantly influenced by the water temperature as reported, despite similar or higher CT values applied during warmer periods. Thus, the disinfection of resistant microorganisms with ozone can also be an efficient process at lower water temperature.

ASFB have been shown to be a conservative indicator for Cryptosporidium and Giardia up to a 1st stage filtration and the ASFB Log removals can be used to estimate Log removals for Cryptosporidium and Giardia: compared to ASFB, the Log removals for Cryptosporidium or Giardia are at least equal or 50% higher, respectively. Thus, the monitoring of ASFB along a drinking water treatment process could be a useful tool for performing risk analysis for parasites such as Cryptosporidium and Giardia, and would further allow integration of daily variability into a risk analysis.     

Ion-exchange membranes made of semi-interpenetrating polymer networks,used for pervaporation-assisted esterification and ion transport

Ionic membranes were prepared by blending poly(vinyl alcohol) (PVA) with an ionic polymer. Semi-interpenetrating polymer networks (sIPN) in which the crosslinked PVA chains trap the ionic polymer were obtained by using a heat treatment at 180 °C or dibromoethane vapor at 140 °C, respectively, for poly (styrene sulfonic acid) (PSSH), poly (sodium styrene sulfonate) (PSSNa), poly (acrylic acid) (PAA) or poly (dimethyl dimethylene piperidinum chloride) (PDMeDMPCl) as the ionic polymer. The stability of the sIPN membranes in some liquid media was studied to select the appropriate membranes for the envisaged applications. The thermally crosslinked PVA/PSSH membranes showed an effective catalytic effect on the esterification reaction between n-propanol and propanoic acid. An active composite membrane made of a layer of PVA/PSSH deposited on a dense PVA layer of an industrial dehydration membrane exhibited both high catalytic activity and high selectivity to water in the pervaporation-assisted esterification. The values of the counter-ion transport number indicated that some crosslinked ionic membranes have good ion permselectivity.     

Cytoskeleton and cell cycle control during meiotic maturation of the mouse oocyte: integrating time and space

During meiotic maturation of mammalian oocytes, two successive divisions occur without an intermediate phase of DNA replication, so that haploid gametes are produced. Moreover, these two divisions are asymmetric, to ensure that most of the maternal stores are retained within the oocyte. This leads to the formation of daughter cells with different sizes: the large oocyte and the small polar bodies. All these events are dependent upon the dynamic changes in the organization of the oocyte cytoskeleton (microtubules and microfilaments) and are highly regulated in time and space. We review here the current knowledge of the interplay between the cytoskeleton and the cell cycle machinery in mouse oocytes, with an emphasis on the two major activities that control meiotic maturation in vertebrates, MPF (Maturation promoting factor) and CSF (Cytostatic factor).     

Fast continuous collision detection and handling for desktop virtual prototyping

This paper presents an overview of our recent work on continuous collision detection methods and constraints handling for rigid polyhedral objects. We demonstrate that continuous collision detection algorithms are practical in interactive dynamics simulation of complex polyhedral rigid bodies and show how continuous collision detection and efficient constraint-based dynamics algorithms allow us to perform various virtual prototyping tasks intuitively, precisely and robustly on commodity desktop computers. Especially, we present two applications of our system to actual industrial cases. We note that both tasks are performed with a simple 2D mouse on a high-end computer.     

Combined Post-harvest Treatments for Improving Quality and Extending Shelf-Life of Minimally Processed Broccoli Florets (<Emphasis Type="Italic">Brassica oleracea var. italica</Emphasis>)

Broccoli is an important source of many nutritional and bioactive compounds. However, its shelf-life is very short due to physicochemical losses and microbiological degradation. This study was undertaken to implement treatments that could improve the quality of ready-to-eat (RTE) broccoli during storage by evaluating the effect of pre-treatment with calcium chloride (CaCl₂) and alginate coating on the physicochemical and microbial properties of RTE broccoli. Broccoli florets were pre-treated with three different concentrations of CaCl₂ (1, 2.5, and 4 g L^?1), then coated with an alginate formulation (13 g L^?1) and stored at 4 °C for 24 days. Texture, color, weight loss, respiration rate, and total mesophilic flora (TMF) counts were evaluated at days 0, 3, 7, 14, and 24 of storage. The obtained results in this study showed that combining pre-treatment with calcium and alginate coating led to reducing the weight loss and respiration rate of broccoli, maintaining its color and texture as well as extending its shelf-life by 6 days. These results not only allowed reducing post-harvest losses resulting in the loss of the product but also have a major impact on the environment and resources involved in the production process.     

Lead, cadmium and aluminum in Canadian infant formulae, oral electrolytes and glucose solutions

Lead (Pb), cadmium (Cd) and aluminum (Al) were determined in 437 individual samples of infant formulae, oral electrolytes and 5% glucose solutions available in Canada. In the electrolytes, Cd and Pb concentrations were all below 0.01 and 0.041 ng g(-1), respectively. In the 5% glucose solutions, Pb and Cd levels averaged 0.01 and 0.09 ng g(-1), respectively. Reported on an as-consumed basis, Pb levels in milk- and soya-based formulae averaged 0.90 and 1.45 ng g(-1), respectively, while Cd levels averaged 0.23 and 1.18 ng g(-1), respectively Average Al levels on an as-consumed basis were 440 ng g(-1) (range 10-3400 ng g(-1)) in milk-based formulae and 730 ng g(-1) (range 230-1100 ng g(-1)) in soy-based formulae. Al concentrations increased in the following order: plain formula < low-iron formula < iron-supplemented formula < casein hydrolysate formula ≈ premature formula ≤ soy formula. For example, in the powdered formulae, average Al concentrations were 18 ng g(-1) for plain milk-based, 37 ng g(-1) for low-iron, 128 ng g(-1) for iron supplemented, 462 ng g(-1) for lactose-free, 518 ng g(-1) for hypoallergenic and 619 ng g(-1) for soy-based formula. Al concentrations, as-consumed, increased with decreasing levels of concentration: powder < concentrated liquid < ready-to-use. Formulae stored in glass bottles contained between 100 and 300 ng g(-1) more Al than the same formulae stored in cans. The source of the increased Al did not appear to be the glass itself, because most electrolytes and glucose solutions, also stored in glass, contained less than 8 ng g(-1) Al. Corresponding differences in Pb and Cd levels were not observed. Al concentrations varied substantially among manufacturers; however, all manufacturers were able to produce plain milk-based formulae containing less than 50 ng g(-1) Al, i.e. within the range of Al concentrations found in human milk. Next to soya-based and hypoallergenic formulae, premature formulae contained among the highest concentrations of Al, ranging 851-909 ng g(-1) from one manufacturer and 365-461 ng g(-1) from another.     

Surface properties and cell adhesion onto allylamine-plasma and amine-plasma coated glass coverslips

Surface properties of nanoparticles to be used for radioimmunotherapy need to be optimized to allow antibody conjugation while ensuring biocompatibility. We aimed to investigate cell adhesion and proliferation onto different coatings to be used for nanoparticles. C, CH _x or SiO _x coatings deposited onto glass coverslips by magnetron deposition as well as nitrogen functionalized materials synthetized using different reactive sputtering conditions and PPAA (plasma polymerized allylamine) coating, were compared. Amine functionalization did increase hydrophilicity in all the materials tested. Biocompatibility was assessed by measuring cell viability, morphology, attachment, spreading, and pro-inflammatory cytokine secretion. The results show that C and CN _x were the most biocompatible substrates while SiO _x and SiO _x N _y were the most toxic materials. PPAA coatings displayed unexpectedly an intermediate biocompatibility. A correlation could be observed between wettability and cell proliferation except for C coated surface, indicating that more complex processes than hydrophilicity alone are taking place that affect cell functions.