Use of green fluorescent protein expressing Salmonella Stanley to investigate survival, spatial location, and control on alfalfa sprouts.

Laser scanning confocal microscopy (LSCM) was used to observe the interaction of Salmonella Stanley with alfalfa sprouts. The green fluorescent protein (gfp) gene was integrated into the chromosome of Salmonella Stanley for constitutive expression, thereby eliminating problems of plasmid stability and loss of signal. Alfalfa seeds were inoculated by immersion in a suspension of Salmonella Stanley (ca. 10(7) CFU/ml) for 5 min at 22 degrees C. Epifluorescence microscopy demonstrated the presence of target bacteria on the surface of sprouts. LSCM demonstrated bacteria present at a depth of 12 microm within intact sprout tissue. An initial population of ca. 10(4) CFU/g seed increased to 7.0 log CFU/g during a 24-h germination period and then decreased to 4.9 log CFU/g during a 144-h sprouting period. Populations of Salmonella Stanley on alfalfa seeds decreased from 5.2 to 4.1 log CFU/g and from 5.2 to 2.8 log CFU/g for seeds stored 60 days at 5 and 22 degrees C, respectively. The efficacy of 100, 200, 500, or 2,000 ppm chlorine in killing Salmonella Stanley associated with sprouts was determined. Treatment of sprouts in 2,000 ppm chlorine for 2 or 5 min caused a significant reduction in populations of Salmonella Stanley. Influence of storage on Salmonella Stanley populations was investigated by storing sprouts 4 days at 4 degrees C. The initial population (7.76 log CFU/g) of Salmonella Stanley on mature sprouts decreased (7.67 log CFU/g) only slightly. Cross-contamination during harvest was investigated by harvesting contaminated sprouts, then directly harvesting noncontaminated sprouts. This process resulted in the transfer of ca. 10(5) CFU/g Salmonella Stanley to the noncontaminated sprouts.     

Étude de l'aspect cornbinatoire de la gestion des conflits dans un atelier discontinu

The combinatorial angle of management of batch processes or job‐shop for fine chemicals is presented. Indeed, the order of priority for product recipes, which allows one to determine the first batch to be loaded, has a strong combinatorial aspect. When dealing with stochastic algorithms, this aspect requires a precise and non‐redundant numbering of the orders of priority. A fairly complex mathematical study based on a family of pseudo‐orthogonal polynomials provides a non‐recursive formula easy to implement.     

Remote sensing by nuclear quadrupole resonance

Detection of explosives has the flavor of those mathematical problems that are not invertible. It is easier to hide explosives than to find them. Many approaches have been proposed and executed for the remote detection of explosives, contraband materials, weapons of mass destruction, currency, etc. Most detection technologies suffer from a common problem: the features they look for, such as discontinuities in electrical conductivity, are not unique properties of the target but are contained, to some degree, in the more benign surroundings. Such a degeneracy leads to “clutter” in the response. For example, resolving the false alarms generated by this clutter can determine the rate of advance of a conventional electromagnetic metal detector employed as a landmine detector. One approach that provides a “unique” signature is nuclear quadrupole resonance (NQR) (the technique is also called QR, to avoid confusion with strictly nuclear techniques). This paper outlines the important physical principles behind the use of NQR for remote detection, indicates areas of applicability, and presents results of field trials of a prototype landmine detection system     

Imaging E-selectin expression following traumatic brain injury in the rat using a targeted USPIO contrast agent

Introduction  The aim of this work was to map E-selectin expression in a traumatic brain injury model using a newly-designed MR contrast agent. Iron cores, responsible for susceptibility effects and therefore used as T2* contrast agents, need to be coated in order to be stabilized and need to be targeted to be useful. Methods  We have designed a molecule coating composed, at one end, of bisphosphonate to ensure anchorage of the coating on the iron core and, at the other end, of Fukuda’s defined heptapeptide known to target selectin binding sites. Conclusion  The synthesized nanoparticles were able to non-invasively target the traumatic brain lesion, inducing a specific T2* decrease of about 25% up to at least 70 min post-injection of the targeted contrast agent.     

Cryotolerance of Lactobacillus delbrueckii subsp. bulgaricus CFL1 is influenced by the physiological state during fermentation

To better understand the effects of freezing and frozen storage on different characteristics of the cell state, the influence of the physiological state, as defined by fermentation pH and harvesting time, and the freezing medium on the cryotolerance of Lactobacillus bulgaricus CFL1 was investigated. Esterase activity, membrane integrity, cultivability and acidification activity were quantified during culture with and without pH control, and during freezing and frozen storage at ?20 °C. The preservation of esterase activity and membrane integrity was not related to starter functionalities such as cultivability and acidification activity. Cell cryotolerance increased with fermentation time or when cells were harvested during culture at pH 5 and frozen, as compared with fermentations at pH 6 or without pH control. Long-term cell cryotolerance could be predicted by determining an early physiological parameter such as a low initial acidification activity when the cells are harvested.     

Molecular Study of a Hoxa2 Gain-of-Function in Chondrogenesis: A Model of Idiopathic Proportionate Short Stature

In a previous study using transgenic mice ectopically expressing Hoxa2 during chondrogenesis, we associated the animal phenotype to human idiopathic proportionate short stature. Our analysis showed that this overall size reduction was correlated with a negative influence of Hoxa2 at the first step of endochondral ossification. However, the molecular pathways leading to such phenotype are still unknown. Using protein immunodetection and histological techniques comparing transgenic mice to controls, we show here that the persistent expression of Hoxa2 in chondrogenic territories provokes a general down-regulation of the main factors controlling the differentiation cascade, such as Bapx1, Bmp7, Bmpr1a, Ihh, Msx1, Pax9, Sox6, Sox9 and Wnt5a. These data confirm the impairment of chondrogenic differentiation by Hoxa2 overexpression. They also show a selective effect of Hoxa2 on endochondral ossification processes since Gdf5 and Gdf10, and Bmp4 or PthrP were up-regulated and unmodified, respectively. Since Hoxa2 deregulation in mice induces a proportionate short stature phenotype mimicking human idiopathic conditions, our results give an insight into understanding proportionate short stature pathogenesis by highlighting molecular factors whose combined deregulation may be involved in such a disease.     

'I Think Home is More than a Building': Young Home(less) People on the Cusp of Home,Self and Something Else

This paper explores research undertaken with young home(less) people in Sydney in which I specifically pursue ideas of home and belonging in the inner city. In a context in which young home(less) people are seen to 'lack' both identity and place, the responses of young people indicate the fragility and importance of relations of space and self.     

Removal of total dissolved solids, nitrates and ammonium ions from drinking water using charge-barrier capacitive deionisation

A charge-barrier capacitive deionisation system was tested for electrochemical removal of Total Dissolved Solids (TDS), nitrates and ammonium ions. Several experiments were conducted with inorganic species spiked in tap water. The system efficiency was first evaluated using experimental statistical designs with different concentrations of NaCl (150 to 3000 mg/L). The raw water conductivity and the targeted residual TDS in treated water were the key process variables. Power consumption increased linearly as the difference between these two values increased. Water recovery rate and electrical consumption, which varied respectively from 63.9% to 95.8% and from 0.45 to 5.35 kWh/m³, were adequately described by a simple linear regression model (R²: 0.98 and 0.99, respectively). Additional experiments performed on nitrates (100 mg N-NO₃/L) and ammonium ions (1000 mg N-NH₄/L) showed high levels of removal. A rise in TDS concentration led to a decrease in their removal due to the competition for electrodes carbon adsorption sites. It was concluded from this study that this technology offers an innovative alternative for demineralising water. However, assays should be conducted in natural waters and in a steady-state manner to confirm data obtained and get long-term performance.