Thermal desorption of polychlorobiphenyls from contaminated soils and their hydrodechlorination using Pd- and Rh-supported catalysts.

This paper reports about a combined technology for soil remediation from PCBs using the thermal desorption technique coupled with the catalytic hydrogenation of recovered PCBs. The reactor is a bench scale rotating desorption furnace through which nitrogen is flushed and used as carrier gas of desorbed PCBs. The latter are condensed into an hexane or hexane-acetone (1:1 v/v) solution that is then hydrogenated using phosphate-supported Pd or Rh as catalyst. The analysis of the treated soil, under variable operative conditions (temperature and desorption time), shows that the total (99.8%) decontamination from PCBs occurs. The recovery yield of the desorbed PCBs is better than 75% and the subsequent hydrogenation reaches 63% of the collected PCBs in 5h or 100% in 12h.

Comparative life cycle assessment study on environmental impact of oil production from micro-algae and terrestrial oilseed crops.

In this study the LCA methodology is applied in order to satisfy two goals: i) to evaluate the hot spots in site-specific production chain of biodiesel from terrestrial and micro-algae feedstock; ii) to compare quantitatively, utilizing primary data, the impacts of the first generation in respect to the third generation bio-fuels. Results show that micro-algae are neither competitive yet with traditional oil crops nor with fossil fuel. The use of renewable technologies as photovoltaics and biogas self production might increase the competitiveness of micro-algae oil. Further investigations are however necessary to optimize their production chain and to increase the added value of co-products.

Neuronal cell death: searching for the smoking gun.

During the past year,several model systems have been developed to identify cellular and biochemical events involved in neuronal cell death, to investigate the role of bcl-2 in cell survival, and to characterize the relationship between cell death and the cell cycle.

Localization of tissue plasminogen activator mRNA in adult rat brain.

The distribution of tissue plasminogen activator (tPA) messenger RNA in rat brain was studied using in situ hybridization with 35S UTP-labeled RNA probes derived from a full-length tPA cDNA. Sense strand controls produced low, even backgrounds, with small elevations in the hippocampus. Full-length antisense probes produced strong signals over cerebral ventricular ependyma (including ependyma of the subcommissural organ), meninges, blood vessels, and Purkinje cell layer of the cerebellum, as well as strong signals over scattered cells throughout the brain. Some of these scattered labeled cells were large with lightly stained nuclei, while others were small with darkly stained nuclei. The large labeled cells, which were probably neurons, constituted 6% and 8% of cells in the brain stem and neocortex, respectively, and 100% of Purkinje cells. The small cells, which were present in all areas of the brain, constituted 3-11% of cells in individual brain areas.

The influence of delayed renal allograft function on long-term outcome in the cyclosporine era.

The influence of delayed renal graft function on long-term allograft outcome remains uncertain. All 495 cyclosporine treated cadaver donor renal transplants within a single center were analyzed with respect to dialysis dependence in the early posttransplant period. When compared with immediate allograft function, dialysis dependence for more than one week posttransplant was associated with prolonged cold ischemia time (27 +/- 11 vs 32 +/- 12 hours), cytotoxic antibodies > 30% (14% vs 25%), black race (29% vs 41%), increased incidence of acute rejection in the first year posttransplant (31% vs 67%) and inferior 1-year (85% vs 52%) and 5-year (68% vs 33%) graft survival among primary transplants. No adverse effect however was noted on renal function in long-term survivors.

Continuous fiber reinforced composite materials as alternatives for metal alloys used for dental appliances.

Two types of uniaxially oriented long S2-glass fiber reinforced composites were prepared for use in various dental appliances. Matrix polymers were polycarbonate (PC) and bisphenol A bis (2-hydroxy-propyl) methacrylate (Bis-GMA) based copolymers. Flexural tests were conducted on the composites using a procedure which simulates clinical usages. To evaluate the adhesion between the composites and the adhesive, the single-lap shear test was conducted. Mechanical properties of the small cross-sectional composite strips were superior to those used previously in clinical studies.

Transosseous reconstruction of temporalis muscle for pterional craniotomy: technical note.

Temporalis muscle asymmetry is a bothersome complication of pterional craniotomy, resulting from atrophy, malposition, and unreliable fixation. The authors describe a simple, quick, and inexpensive technique to achieve firm, anatomic reapproximation of the temporalis muscle to its bone attachment.

PC12 cells overexpressing tissue plasminogen activator regenerate neurites to a greater extent and migrate faster than control cells in complex extracellular matrix.

PC12 cells were stably transfected with expression vectors containing rat tissue plasminogen activator (tPA) under control of either a cytomegalovirus or rous sarcoma virus promoter. Cell lines were characterized using protease assays, ELISAs, immunoblots, northern blots, and Southern blots. Control PC12 cells or cells containing vectors alone released about 1 pg tPA/cell/24 h, whereas cells stably transfected with a tPA cDNA released 2-5 pg tPA/cell/24 h. A strong correlation existed between the amount of tPA released and the ability of cells to degrade extracellular matrix. Experiments with protease inhibitors and antibodies against tPA and plasminogen indicated that degradation of matrix involved tPA-generated plasmin and that the amount of matrix degraded was dependent on the amount of tPA released. Cells expressing high levels of tPA migrated on a three-dimensional matrix about twice as fast as control cells and regenerated neurites within three-dimensional gels of Matrigel to a greater extent than control cells. Antibodies that inhibited tPA and plasminogen decreased migration and neurite regeneration, indicating that tPA was involved in both events, PC12 cells overexpressing tPA should provide a useful model system for investigating neural functions of tPA including its role in migration and regeneration.

Death in the balance.

Two major hypotheses concerning programmed cell death are that it is the end result of a gene expression pathway and that it is the cellular response to conflicting growth control signals. These ideas are examined, and their potential applicant to neuronal cell death during development is discussed. Since most mammalian genes involved in cell death have other functions, it is possible that a novel set of death genes does not exist in mammals. Instead, the genes identified may serve to link an initial stimulus to die with the cellular events that actually cause death, primarily by providing regulatory signals that direct the decision. The idea of cell death as a response to conflicting growth regulatory signals, initially derived from studies on cycling, non-neuronal cells, is applied to proliferating neuronal precursors and postmitotic neurons. How neuronal death during development might be the outcome of conflicting signals, and how retinoblastoma protein might negotiate "death by conflict" in different populations of neurons is discussed.

Thymic hyperplasia following successful chemotherapy. A report of two cases and review of the literature.

True thymic hyperplasia is rare in adults. The authors have encountered this entity in two patients who were deemed disease-free following combination chemotherapy for malignant disease. It cannot be assumed that the development of a mediastinal mass or its persistence following chemotherapy is due to recurrent or residual disease. The interrelationship between the immunosuppressive effects of neoplasia and chemotherapy with the resultant thymic overgrowth remains to be clarified.

Probing the function of Drosophila melanogaster accessory glands by directed cell ablation.

The female Drosophila melanogaster fly undergoes behavioral changes after mating, including an increase in egg laying and an avoidance of remating. Accessory-gland products elicit these changes transiently when introduced into unmated female flies. We report here the generation and phenotype of flies that lack functional accessory-gland main cells as a consequence of genetically directed delivery of diphtheria toxin subunit A to those cells. Only main-cell secretions are essential for the short-term inhibition to remating; no other products of the genital tract can replace their function. Long-term inhibition to remating depends only on the storage of sperm in the female. Both sperm and main-cell secretions have roles in the increase of egg laying by the mated female. In addition to full-strength diphtheria toxin, we used low-activity toxins to kill only those cells that express toxin at high levels. These transgenic strains that express diphtheria toxins of different strengths in accessory-gland main cells will be useful in further defining the role of these cells.

Localization of tissue plasminogen activator mRNA in the developing rat cerebellum and effects of inhibiting tissue plasminogen activator on granule cell migration.

Tissue plasminogen activator (tPA) mRNA was localized in the developing cerebellum and the potential role of tPA in migration of cerebellar granule cells was investigated. Proteolytic assays and Northern blots showed little variation in levels of tPA proteolytic activity or tPA mRNA expression in the developing cerebellum. The distribution of cerebellar tPA mRNA at different ages was visualized by in situ hybridization histochemistry. At postnatal day 7 (P7), most labeled cells were in the internal granule layer or developing white matter, and very few if any premigratory granule cells contained tPA mRNA. Although the molecular layer contained labeled cells at all ages, cell counts indicated that a greater percentage of cells in the molecular layer contained tPA mRNA during adulthood than during the period of granule cell migration. The most striking change in tPA mRNA expression was in Purkinje neurons, most of which began to express tPA mRNA between P7 and P14. The potential role of tPA in granule cell migration was investigated by performing migration assays in cerebellar slice explants in the presence or absence of protease inhibitors. The presence of inhibitors did not affect the distance that granule cells migrated. Data in the present study do not support a role for tPA in granule neuron migration; however, they do indicate that tPA is both spatially and temporally regulated during cerebellar development. Possible functions of tPA in the cerebellum are discussed.