Project Performance Control in Reconstruction Projects

Cost, schedule, and quality are the main indicators of performance in construction projects. These indicators are highly interrelated and require some balance and trade-off among them to achieve efficient overall control over project performance. Focusing on these performance indicators, the primary objective of this study is to investigate the use of conventional control techniques in projects involving reconstruction of occupied buildings. To facilitate this analysis, performance data have been collected, using a questionnaire survey, from 25 reconstruction and 15 new construction projects. The survey was followed by structured interviews with construction practitioners and project participants to elicit success-related factors and to identify some of the unique problems affecting the control of reconstruction projects. Using the collected data, performance comparison was conducted between new and reconstruction projects along with a detailed analysis of the suitability of existing techniques for the control of the cost, schedule, and quality in reconstruction projects.     

An improved method to create nitrocellulose particles suitable for the immobilization of antigen and antibody

A method is described for producing 1-3 microns sized particles of nitrocellulose (NC) which are able to absorb protein. Protein is absorbed onto preformed particles made by first dissolving a sheet of nitrocellulose paper in DMSO, and then precipitating it with sodium carbonate/bicarbonate buffer. The efficiency of binding is the same as that of an equivalent sheet of non-processed NC filter paper. Antibodies absorbed onto preformed particles are not exposed to DMSO and carbonate buffer and therefore retain a high antigen binding capacity. Antigen and antibody-absorbed NC preformed particles were used to capture antibody and antigen, respectively. Using lysis buffer, the captured antibodies and antigens were readily released from the NC particles. This makes the latter an appropriate matrix for immunoprecipitation assays either for an antigen or for specific antibody. Antigen-coated NC particles were specifically aggregated ('agglutinated') by specific antibodies and thus can be used in semi-quantitative tests.     

A new two-impinging-streams heterogeneous reactor

The characteristics of a new heterogeneous reactor of the “two impinging streams” type, suitable for gas-solid heat and mass-transfer operations, were investigated. The operating limits of the reactor, with respect to gas and solid particles mass flow rate and pressure drop, were determined; scale-up criteria with respect to the hydrodynamics of the reactor were also established. It has been found that, under certain conditions, the introduction of solid particles into the gas stream lowers the pressure drop on the reactor. In addition, the maximal pumping energy per kg of solids transported through the reactor by the air is much lower than in a fluidized-bed-type reactor. A stochastic model based on Markov processes was developed which closely describes the behavior of the solid particles in the reactor. A technique based on this model was employed for determining the residence time distribution of the particles in the reactor.     

Etheno adducts in spleen DNA of SJL mice stimulated to overproduce nitric oxide

In order to investigate specific DNA damage caused by nitric oxide (NO) induced lipid peroxidation, levels of promutagenic etheno adducts 1,N6-ethenodeoxyadenosine (epsilondA) and 3,N4-ethenodeoxycytidine (epsilondC) were measured in spleen DNA of SJL mice induced to produce high levels of NO by injection of RcsX (pre-B-cell lymphoma) cells. epsilondA and epsilondC levels were quantified by an ultrasensitive immunoaffinity-32P-post-labeling method. Spleen DNA of control mice (n = 5) had background levels of 9.2+/-5.4 epsilondA adducts per 10(9) dA and 13.1+/-5.7 epsilondC adducts per 10(9) dC. In RcsX cell-injected mice (n = 7), levels of these adducts were elevated approximately 6-fold, i.e. 53.9+/-39.4 epsilondA per 10(9) dA and 83.5+/-57.8 epsilondC per 10(9) dC (P < 0.05). Mice injected with RcsX cells and also treated with NG-methyl-L-arginine (NMA), an inhibitor of inducible nitric oxide synthase (n = 6), had significantly reduced levels (P < 0.05) of both epsilondA and epsilondC (13.5+/-5.7 epsilondA per 10(9) dA and 28.2+/-15.7 epsilondC per 10(9) dC). These findings constitute the first available evidence of formation of etheno adducts associated with NO overproduction in vivo. The adducts were presumably formed from lipid peroxidation products such as trans-4-hydroxy-2-nonenal (HNE), generated via oxidation of lipids by peroxynitrite. The results suggest that etheno-DNA adducts, among other types of damage, may contribute to the etiology of cancers associated with chronic infection/inflammation in which NO is overproduced.     

Functional correlation between histamine metabolism and worm expulsion in Trichinella spiralis

Mucosal mast cell activity was quantified by measuring histamine forming capacity (HFC) of the gastric mucosa and histamine content in the intestinal tissues of mice infected with T. spiralis. The results wee correlated with the kinetics of worm expulsion. It was found that T. spiralis resulted in significant elevation of HFC by the day 6 post infection (p.i.) which reached a maximal value at day 9, a time when approximately 50% of the established worm burden had been expelled. Histamine content of the intestinal tissues followed the same pattern. No intestinal worms were present by day 28 of infection and there was a gradual reduction in HFC and histamine content which had returned almost to control values by that time. Significant inverse correlation between individual worm burdens and HFC was detected.     

Inhibition of T lymphocyte activation by cAMP is associated with down-regulation of two parallel mitogen-activated protein kinase pathways, the extracellular signal-related kinase and c-Jun N-terminal kinase

The induction of T cell proliferation requires signals from the TCR and a co-receptor molecule, such as CD28, that activate parallel and partially cross-reactive signaling pathways. These pathways are disrupted by agonists that utilize adenylate cyclase and cAMP-dependent protein kinase A (PKA). We found that the adenylate cyclase activator, forskolin, inhibits anti-CD3-induced shift in Lck electrophoretic mobility, suggesting an intervention at the TCR-coupled phosphoinositide turnover that precedes the activation of PKC. The shift of Lck following direct PKC activation by 12-O-tetradecanoyl phorbol 13-acetate, which bypasses early receptor-triggered biochemical events, is insensitive to forskolin. Nevertheless, forskolin also inhibits PKC downstream events, such as c-jun expression, which is critical for the activation process of T cells. To further analyze potential cross points between positively and negatively regulating signaling pathways in T cells, we tested the effects of activators of the adenylate cyclase or PKA on two parallel mitogen-activated protein kinase signaling pathways mediated by extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase. Using a PKC-specific inhibitor, GF109203X, or PKC-depleted T cells, we found that a large part of the anti-CD3-induced ERK activation is PKC dependent. Both PKC-dependent and -independent activation of ERK were sensitive to inhibition by forskolin or a cell-permeable cAMP analogue, dbcAMP. Furthermore, the effect of 12-O-tetradecanoyl phorbol 13-acetate and ionomycin, which synergized to fully activate c-Jun N-terminal kinase, was also sensitive to inhibition by forskolin. Our results suggest that PKA inhibits T cell activation by interfering with multiple events along the two signaling pathways operating downstream of the TCR and the CD28 co-receptor molecules.     

Metabolism of vicine and convicine in rat tissues: absorption and excretion patterns and sites of hydrolysis

The objectives of this study were to determine whether dietary vicine and convicine were absorbed by rat tissue, and to determine their excretion patterns and/or sites of degradation. Orally administered vicine and convicine were excreted in relatively low amounts via the kidney and faeces. However, no vicine or convicine was detected in the blood, liver, kidney or muscle tissue of rats which had been fed these compounds. In-vitro studies demonstrated that vicine and convicine were not hydrolysed in liver, kidney, muscle, caecal wall or intestinal wall homogenates. In contrast, digesta samples from the large intestine and caeca were able to rapidly hydrolyse these compounds, with the concomitant formation of new compounds. Digesta from the stomach and small intestine promoted the slow hydrolysis of these compounds, as did fresh faecal samples. These results would suggest that vicine and convicine are absorbed by the rat in only limited amounts, are not hydrolysed by rat tissues, and are rapidly cleared from tissue via the kidney. The bulk of the dietary vicine and convicine are hydrolysed in the large intestine and caecum.     

Coalescence model of particles in coaxial impinging streams

Coalescence is mainly affected by particle-to-particle collisions. A new model based on an equation expressing the condition for interparticle collision rate as well as the equation of motion of a single particle, has been developed for coaxial impinging streams. The model assumes that coalescence takes place only between small and large particles. In addition to the drag force usually influencing the behavior in impinging streams, the force acting on a large particle due to its collisions with small particles, has also been accounted for in the equation of motion. The effect of the change of the mass of the large particles on the acceleration due to coalescence with small particles, has also been included in the model. The model enables one to predict the composition of the product after coalescence from the composition of the feed and the operating conditions of the coalescentor.