Regulation of surface and intracellular expression of CTLA4 on mouse T cells

CTLA4 is a cell surface molecule that shares 30% homology with CD28 and binds B7 family members with high affinity. Analysis of surface expression on murine T cells revealed up-regulation after stimulation with anti-CD3 mAb in vitro and further augmentation after the addition of exogenous IL-2 or anti-CD28 mAb. The effects of IL-2 and anti-CD28 mAb were additive and in part independent, as anti-CD28 mAb increased anti-CD3 mAb-induced T cell CTLA4 expression in IL-2-deficient mice. In contrast, CTLA4 expression was only minimally augmented by the addition of IL-4, IL-6, IL-7, or IL-12. Expression of CTLA4 induced by anti-CD3 mAb was inhibited by anti-IL-2 plus anti-IL-2R mAbs. Inasmuch as these agents prevented T cell proliferation, the effects of cell cycle inhibitors also were examined. Drugs blocking at G1 (cyclosporin A, mimosine) or S (hydroxyurea) phase inhibited the up-regulation of CTLA4 induced by anti-CD3 mAb, suggesting that entry into the cell cycle was necessary to increase the expression of CTLA4. The kinetics of intracellular expression of CTLA4 after stimulation with anti-CD3 mAb paralleled those of surface expression, but surprisingly, much more CTLA4 was localized in the cytoplasm of T lymphocytes than on the cell surface at each time point. Importantly, surface CTLA4 was rapidly internalized intracellularly, which may explain the low levels of expression generally detected on the cell surface. We conclude that both CD28 and IL-2 play important roles in the up-regulation of CTLA4 expression. In addition, the cell surface accumulation of CTL4 appears to be primarily regulated by its rapid endocytosis.     

Methane oxidation – effect of support, precursor and pretreatment conditions – in situ reaction XPS and DRIFT

The methane combustion was studied on Pd supported catalysts searching for explanation of the effects of support, pretreatment and induction periods on the activity of the Pd/alumina, Pd/zirconia, Pd/niobia and Pd/niobia/alumina catalysts. Characterization of methane oxidation in XPS and DRIFTS chambers indicated that an induction period of at least 6 h is necessary to form Pd in a higher oxidation state Pd^2+δ coexisting with PdO as the surface active phases. Similarly, DRIFTS measurements showed distinct species at the surface during the oxidation of methane after 6 h, indicating formate species on Pd/Alumina and CH_x-species and O₂⁻ adsorption on the Pd/zirconia catalyst, suggesting different reaction mechanisms. The reverse pathway depends on the surface modification due to the temperature and induction time.

The activity of the Pd/niobia/alumina was better than of the Pd/niobia. The effect of the precursor was observed, indicating that palladium nitrate precursor allows to lower dispersion but better performance on methane oxidation. The stability was studied and shows that the Pd/zirconia catalyst was stable and is regenerated, while the Pd/alumina catalyst deactivates very fast and is not regenerated. The effect of pretreatment of the catalysts on the methane oxidation showed different behavior depending of the support.     

Heuristic Solutions for Locating Health Resources

Of the three metaheuristic strategies tested that can help determine healthcare facility locations, scatter search performed the best and fastest. Hypoglycemia, or low blood sugar, can cause many health problems, including blurred vision, mental confusion, and speech impairment. If someone becomes severely hypoglycemic and doesn't recover quickly, he or she might lose consciousness and go into a diabetic coma. If that happens, the person must get treated within 15 to 20 minutes; otherwise, he or she almost certainly will suffer devastating physical damage - possibly neuropathy, or blindness - or might even die. Because the risk of permanent neurological deficit increases as the coma is prolonged, it's important for people with diabetes to live no further than 20 minutes (known as the critical time) from their closest health center. Facility location problems such as this involve determining where to install resources and how to assign potential customers to those resources. Most studies on location problems are framed under deterministic conditions. Our proposed solution is more realistic. We adapted, implemented, and compared three metaheuristic strategies - scatter search, tabu search. and variable neighborhood search - to find the best locations in Spain's Burgos province to place health resources for treating people in diabetic comas. To check the efficiency of SS, TS, and VNS, we used instances of the well-known OR-Library as well as real data from the Burgos area in northern Spain. Using metaheuristics is a good option when the problem's complexity prevents us from using a commercially available solver to solve it exactly. This is especially true here, because we're considering hundreds of locations.     

Efficacy of neutral electrolyzed water (NEW) for reducing microbial contamination on minimally-processed vegetables

Consumption of minimally-processed, or fresh-cut, fruit and vegetables has rapidly increased in recent years, but there have also been several reported outbreaks associated with the consumption of these products. Sodium hypochlorite is currently the most widespread disinfectant used by fresh-cut industries. Neutral electrolyzed water (NEW) is a novel disinfection system that could represent an alternative to sodium hypochlorite. The aim of the study was to determine whether NEW could replace sodium hypochlorite in the fresh-cut produce industry. The effects of NEW, applied in different concentrations, at different treatment temperatures and for different times, in the reduction of the foodborne pathogens Salmonella, Listeria monocytogenes and Escherichia coli O157:H7 and against the spoilage bacterium Erwinia carotovora were tested in lettuce. Lettuce was artificially inoculated by dipping it in a suspension of the studied pathogens at 10(8), 10(7) or 10(5) cfu ml(-1), depending on the assay. The NEW treatment was always compared with washing with deionized water and with a standard hypochlorite treatment. The effect of inoculum size was also studied. Finally, the effect of NEW on the indigenous microbiota of different packaged fresh-cut products was also determined. The bactericidal activity of diluted NEW (containing approximately 50 ppm of free chlorine, pH 8.60) against E. coli O157:H7, Salmonella, L. innocua and E. carotovora on lettuce was similar to that of chlorinated water (120 ppm of free chlorine) with reductions of 1-2 log units. There were generally no significant differences when treating lettuce with NEW for 1 and 3 min. Neither inoculation dose (10(7) or 10(5) cfu ml(-1)) influenced the bacterial reduction achieved. Treating fresh-cut lettuce, carrot, endive, corn salad and 'Four seasons' salad with NEW 1:5 (containing about 50 ppm of free chlorine) was equally effective as applying chlorinated water at 120 ppm. Microbial reduction depended on the vegetable tested: NEW and sodium hypochlorite treatments were more effective on carrot and endive than on iceberg lettuce, 'Four seasons' salad and corn salad. The reductions of indigenous microbiota were smaller than those obtained with the artificially inoculated bacteria tested (0.5-1.2 log reduction). NEW seems to be a promising disinfection method as it would allow to reduce the amount of free chlorine used for the disinfection of fresh-cut produce by the food industry, as the same microbial reduction as sodium hypochlorite is obtained. This would constitute a safer, 'in situ', and easier to handle way of ensuring food safety.     

Moving urban water infrastructure asset management from science into practice

iGPI, the National Initiative for Infrastructure Asset Management is a Portuguese collaborative project led by LNEC (National Civil Engineering Laboratory, Portugal) through which 19 water utilities develop their own infrastructure asset management (IAM) systems and plans in a joint training and capacitation programme. Technical assistance to the participating utilities is ensured by LNEC, IST (Technical University of Lisbon) and Addition, a software development company. The water utilities get collective as well as one-on-one support and specific training. They benefit from networking with the other utilities in a common and simultaneous process, with similar difficulties and challenges, leading to an effective sharing of solutions. The developed products, including training materials, templates and guidelines for developing strategic and tactical IAM plans, are available to the general public. This project has greatly contributed to the establishment of reference methodologies and standards for IAM planning, in a range of utilities of widely diverse size and context, effectively defining an accepted best practice. This paper discusses the project's format and its advantages, and goes on to describe the main outcomes, including selected cases and final products.