The progress made over the past three decades in the key elements of pavement management systems was evaluated, and the significant improvements expected over the next 10 years were projected. Eight specific elements of a pavement management system were addressed: functions, data collection and management, pavement performance prediction, economic analysis, priority evaluation, optimization, institutional issues, and information technology. Among the significant improvements expected in pavement management systems in the next decade are improved linkage among, and better access to, databases; systematic updating of pavement performance prediction models by using data from ongoing pavement condition surveys; seamless integration of the multiple management systems of interest to a transportation organization; greater use of geographic information and Global Positioning Systems; increasing use of imaging and scanning and automatic interpretation technologies; and extensive use of formal optimization methods to make the best use of limited resources.

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Antibodies to HBsAg of IgG class enhanced the helper activity of a human T cell clone to promote the in vitro synthesis of immunoglobulins by autologous B lymphocytes. Using two different assay systems, the effect of antigen-specific antibodies on the helper function of a HBsAg-reactive T cell clone was studied. The monoclonal antibody to HBsAg A5C3 (IgG) increased significantly the T cell-dependent production of immunoglobulins by Staphyloccocus aureus-stimulated autologous B lymphocytes. Furthermore, the results obtained with a different type of assay showed that A5C3 also increased the synthesis of antibody to HBsAg by the autologous B cells in the presence of HBsAg and the helper T cell clone. On the other hand, when the monoclonal antibody to HBsAg of IgM class, H5D3 or the F(ab')2 fragment of A5C3 were tested, no significant enhancement of the helper activity of the T cell clone was observed. Experiments performed in mice showed that the in vivo antibody to HBsAg response to low concentrations of HBsAg was significantly enhanced by mixing this antigen with monoclonal antibody to HBsAg of IgG class. No effect was observed when a monoclonal antibody to HBsAg of IgM class was used to prepare the immune-complexed immunogen. The results presented here suggest that antibodies play a critical role in their own production through regulating the activity of helper T cells. This phenomenon might contribute to the increased antibody synthesis of in vivo secondary immune responses and could be of use in designing more efficient vaccine programs in man.

Remaining service life (RSL) has been defined as the anticipated number of years that a pavement will be functionally and structurally acceptable with only routine maintenance. The Kansas Department of Transportation (KDOT) has a comprehensive pavement management system, network optimization system (NOS), which uses the RSL concept. In support of NOS, annual condition surveys are conducted on the state highway system. Currently KDOT uses an empirical equation to compute RSL of flexible pavements based on surface condition and deflection from the last sensor of a falling-weight deflectometer (FWD). Due to limited resources and large size, annual network-level structural data collection at the same rate as the project level is impractical. A rolling-wheel deflectometer (RWD), which measures surface deflections at highway speed, is an alternate and fast method of pavement-deflection testing for network-level data collection. Thus, a model that can calculate RSL in terms of FWD first sensor/center deflection (the only deflection measured by RWD) is desired for NOS.In this study, RWD deflection data was collected under an 18-kip axle load at highway speed on non-Interstate highways in northeast Kansas in July 2006. FWD deflection data, collected with a Dynatest 8000 FWD on the KDOT network from 1998 to 2006, were reduced to mile-long data to match the condition survey data collected annually for NOS. Normalized and temperature-corrected FWD and RWD center deflections and corresponding effective structural numbers (SNeff) were compared. A nonlinear regression procedure in Statistical Analysis Software (SAS) and Solver in Microsoft Excel were used to develop the models in this study.Results showed that FWD and RWD center deflections and corresponding SNeff are statistically similar. Temperature-correction factors have significant influence on these variables.FWD data analysis on the study sections showed that average structural condition of pavements of the KDOT non-Interstate network did not change significantly over the last four years. Thus, network-level deflection data can be collected at four-year intervals when there is no major structural improvement.Results also showed that sigmoimal relationship exists between RSL and center deflection. Sigmoidal RSL models have very good fits and can be used to predict RSL based on center deflection from FWD or RWD. Sigmoidal equivalent fatigue crack-models have also shown good fits, but with some scatter that can be attributed to the nature and quality of the data used to develop these models. FWD data analysis on the study sections showed that average structural condition of pavements of the KDOT non-Interstate network did not change significantly over the last four years. Thus, network-level deflection data can be collected at four-year intervals when there is no major structural improvement.Results also showed that sigmoimal relationship exists between RSL and center deflection. Sigmoidal RSL models have very good fits and can be used to predict RSL based on cen...