Study of Iowa’s Current Road Use Tax Funds (RUTF) and Future Road Maintenance and Construction Needs, 2006

The 81st General Assembly of the Iowa legislature, in Section 85 of House File 868, required the Iowa Department of Transportation (Iowa DOT) to conduct a study of current Road Use Tax Fund (RUTF) revenues, and projected roadway construction and maintenance needs. With input from Iowa’s cities, counties and other interested groups, the Iowa DOT completed this report for submittal to the legislature.

Study of Iowa’s Current Road Use Tax Funds (RUTF) and Future Road Maintenance and Construction Needs, 2006

The 81st General Assembly of the Iowa legislature, in Section 85 of House File 868, required the Iowa Department of Transportation (Iowa DOT) to conduct a study of current Road Use Tax Fund (RUTF) revenues, and projected roadway construction and maintenance needs.

Effective Shoulder Design and Maintenance, 2007

Granular shoulders are an important element of the transportation system and are constantly subjected to performance problems due to wind- and water-induced erosion, rutting, edge drop-off, and slope irregularities. Such problems can directly affect drivers’ safety and often require regular maintenance. The present research study was undertaken to investigate the factors contributing to these performance problems and to propose new ideas to design and maintain granular shoulders while keeping ownership costs low. This report includes observations made during a field reconnaissance study, findings from an effort to stabilize the granular and subgrade layer at six shoulder test sections, and the results of a laboratory box study where a shoulder section overlying a soft foundation layer was simulated. Based on the research described in this report, the following changes are proposed to the construction and maintenance methods for granular shoulders: • A minimum CBR value for the granular and subgrade layer should be selected to alleviate edge drop-off and rutting formation. • For those constructing new shoulder sections, the design charts provided in this report can be used as a rapid guide based on an allowable rut depth. The charts can also be used to predict the behavior of existing shoulders. • In the case of existing shoulder sections overlying soft foundations, the use of geogrid or fly ash stabilization proved to be an effective technique for mitigating shoulder rutting.

Improved nonparametric confidence intervals in time series regressions

Condence intervals in econometric time series regressions suffer fromnotorious coverage problems. This is especially true when the dependencein the data is noticeable and sample sizes are small to moderate, as isoften the case in empirical studies. This paper suggests using thestudentized block bootstrap and discusses practical issues, such as thechoice of the block size. A particular data-dependent method is proposedto automate the method. As a side note, it is pointed out that symmetricconfidence intervals are preferred over equal-tailed ones, since theyexhibit improved coverage accuracy. The improvements in small sampleperformance are supported by a simulation study.

Salt subtraction in patients on maintenance hemodialysis. Efficacy and limitations.

In 6 hypertensive patients with terminal renal failure maintained on hemodialysis, the effects of 'salt subtraction' and of sequential ultrafiltrating were evaluated. Following each of 3 weekly hemodialysis sessions, salt subtraction was carried out by ultrafiltrating 1 liter and simultaneously infusing an equal volume of 5% dextrose. This resulted in a net sodium loss without hypovolemia. After a 2-week period of this procedure, the blood pressure prior to dialysis was lower (156/76 +/- 12/5 mm Hg) than after a comparable number of sequential ultrafiltration sessions (181/88 +/- 10/6 mm Hg; mean +/- SEM). This difference was not statistically significant. At the same time, body weight was comparable at 64.4 +/- 3 and 64.7 +/- 4 kg, respectively. Neither plasma renin activity nor plasma catecholamines responded with a clear increase to either procedure. The limited effect on blood pressure and the renin system of a marked sodium removal during salt subtraction suggests that sodium must still be present in excess in these patients. The procedure of salt subtraction appears safe and subjectively well tolerated, but it can probably not be used as the sole means of decreasing total body sodium without associating dietary measures to reduce sodium intake.

Cytochrome P450 2D6 genotype and methadone steady-state concentrations

A genetic polymorphism of cytochrome P450 2D6 has been described with the existence of poor (zero functional genes), extensive (one or two functional genes), and ultrarapid metabolizers (three or more functional genes). The authors measured the steady-state trough (R)- (i.e., the active enantiomer), (S)-, and (R,S)-methadone plasma levels in opiate-dependent patients receiving methadone maintenance treatment (MMT) and genotyped them for cytochrome P4502D6. The patients' medical records were reviewed to assess the outcome of the MMT with regard to the absence of illicit opiate consumption and to the absence of withdrawal complaints in ultrarapid and poor metabolizers. Of 256 patients included, 18 were found to be poor metabolizers, 228 to be extensive metabolizers, and 10 to be ultrarapid metabolizers. Significant differences were found between genotypes for (R)- (p = 0.024), (S)- (p = 0.033), and (R,S)-methadone (p = 0.026) concentrations to dose-to-weight ratios. For (R)-methadone, a significant difference was found between ultrarapid metabolizers and poor metabolizers (p = 0.009), with the median value in the former group being only 54% of the median value in the latter group. These results confirm the involvement of cytochrome P450 2D6 in methadone metabolism. Although the difference was nonsignificant (p = 0.103), 13 (72%) of the 18 poor metabolizers and only 4 (40%) of the 10 ultrarapid metabolizers were considered successful in their treatment. More studies are needed to examine the influence of the ultrarapid metabolizer status on the outcome of the MMT.

Income maintenance programs and multidimensional screening

This paper examines properties of optimal poverty assistance programs under different informational environments using an income maintenanceframework. To that end, we make both the income generating ability andthe disutility of labor of individuals unobservable, and compare theresulting benefit schedules with those of programs found in the UnitedStates since Welfare Reform (1996). We find that optimal programs closelyresemble a Negative Income Tax with a Benefit Reduction rate that dependson the distribution of population characteristics. A policy of workfare(unpaid public sector work) is inefficient when disutility of labor isunobservable, but minimum work requirements (for paid work) may be usedin that same environment. The distortions to work incentives and thepresence of minimum work requirements depend on the observability andrelative importance of the population's characteristics.

LRF-mediated Dll4 repression in erythroblasts is necessary for hematopoietic stem cell maintenance.

Hematopoietic stem cells (HSCs) are the most primitive cells in the hematopoietic system and are under tight regulation for self-renewal and differentiation. Notch signals are essential for the emergence of definitive hematopoiesis in mouse embryos and are critical regulators of lymphoid lineage fate determination. However, it remains unclear how Notch regulates the balance between HSC self-renewal and differentiation in the adult bone marrow (BM). Here we report a novel mechanism that prevents HSCs from undergoing premature lymphoid differentiation in BM. Using a series of in vivo mouse models and functional HSC assays, we show that leukemia/lymphoma related factor (LRF) is necessary for HSC maintenance by functioning as an erythroid-specific repressor of Delta-like 4 (Dll4) expression. Lrf deletion in erythroblasts promoted up-regulation of Dll4 in erythroblasts, sensitizing HSCs to T-cell instructive signals in the BM. Our study reveals novel cross-talk between HSCs and erythroblasts, and sheds a new light on the regulatory mechanisms regulating the balance between HSC self-renewal and differentiation.

Maintenance Service Level Map, October 13, 2006

Maintenance Service Level Map

Exposure of highway maintenance workers to fine particulate matter and noise

In this study, we assessed the mixed exposure of highway maintenance workers to airborne particles, noise, and gaseous co-pollutants. The aim was to provide a better understanding of the workers' exposure to facilitate the evaluation of short-term effects on cardiovascular health endpoints. To quantify the workers' exposure, we monitored 18 subjects during 50 non-consecutive work shifts. Exposure assessment was based on personal and work site measurements and included fine particulate matter (PM2.5), particle number concentration (PNC), noise (Leq), and the gaseous co-pollutants: carbon monoxide, nitrogen dioxide, and ozone. Mean work shift PM2.5 concentrations (gravimetric measurements) ranged from 20.3 to 321 μg m(-3) (mean 62 μg m(-3)) and PNC were between 1.6×10(4) and 4.1×10(5) particles cm(-3) (8.9×10(4) particles cm(-3)). Noise levels were generally high with Leq over work shifts from 73.3 to 96.0 dB(A); the averaged Leq over all work shifts was 87.2 dB(A). The highest exposure to fine and ultrafine particles was measured during grass mowing and lumbering when motorized brush cutters and chain saws were used. Highest noise levels, caused by pneumatic hammers, were measured during paving and guardrail repair. We found moderate Spearman correlations between PNC and PM2.5 (r = 0.56); PNC, PM2.5, and CO (r = 0.60 and r = 0.50) as well as PNC and noise (r = 0.50). Variability and correlation of parameters were influenced by work activities that included equipment causing combined air pollutant and noise emissions (e.g. brush cutters and chain saws). We conclude that highway maintenance workers are frequently exposed to elevated airborne particle and noise levels compared with the average population. This elevated exposure is a consequence of the permanent proximity to highway traffic with additional peak exposures caused by emissions of the work-related equipment.

Maintenance of neuronal expression of calbindin by a muscular extract in cultures of chick dorsal root ganglion cells.

Calbindin D-28K is a calcium-binding protein which is expressed by subpopulations of dorsal root ganglion cells cultured from 10-day-old (E10) chick embryos. After 7 or 10 days of culture, more than 20% of the ganglion cells are immunostained by an anticalbindin-antiserum; however, after 14 days of culture, the proportion drops to 10%. This fall can be prevented by addition of muscle extract to cultures at 10 days. Thus the transitory expression of calbindin-immunoreactivity by responsive sensory neurons would be not only induced but also maintained by a differentiation factor of muscular origin.

Longer Intervals Between Hematopoietic Stem Cell Transplantation and Subsequent 90Y-Ibritumomab Radioimmunotherapy May Correlate With Better Tolerance.

PURPOSE: This study aimed to evaluate the efficacy and toxicity of radioimmunotherapy (RIT) in recurrent lymphoma after hematopoietic stem cell transplantation (HSCT). METHODS: We reviewed 9 patients, 7 with follicular lymphoma (DLBCL), 1 with mantle cell lymphoma (MCL), and 1 with diffuse large B-cell lymphoma treated with Y-ibritumomab tiuxetan 6 to 140 months after HSCT. Patients underwent In-ibritumomab scintigraphy and were treated 1 week later with standard 14.8 MBq/kg (n = 4) or 11.1 MBq/kg (n = 4) Y-ibritumomab. One patient who had allo-HSCT had reduced activity (70%) treatment. RESULTS: Among the 7 FL patients, we observed complete response (CR) in 2 patients and partial response (PR) in 5 patients. One patient with CR relapsed after 15 months; the other persisted 43.5 months after RIT. Of 5 patients with PR, 3 relapsed between 13 and 17 months; 1 persisted until unrelated death at 11.5 months. The fifth patient with PR received adoptive immunotherapy and improved to metabolic (FDG-PET) CR that persists 45.5 and 41 months after Y-ibritumomab and immunotherapy, respectively. Patients with MCL and DLBCL progressed or experienced stabilization (5 months), respectively. Six patients had grade 1 to 3 bone marrow (BM) toxicity and recovered within 3 months. Three patients having Y-ibritumomab 6, 14, and 24 months after HSCT experienced grade 4 BM toxicity. One of them (RIT 24 months after HSCT) recovered after 3 months, another delayed after 9 months, and the third patient only partially recovered, eventually developed myelodysplasia, and was allografted. CONCLUSIONS: Radioimmunotherapy after HSCT is an effective rescue therapy in FL. However, BM toxicity may be important; 3 of 8 patients treated with standard Y-ibritumomab activity experienced grade 4 BM toxicity, with incomplete recovery 3 months after RIT in 2 patients, both treated early (6 and 14 months) after HSCT.

CD93 is required for maintenance of antibody secretion and persistence of plasma cells in the bone marrow niche.

Plasma cells represent the end stage of B-cell development and play a key role in providing an efficient antibody response, but they are also involved in numerous pathologies. Here we show that CD93, a receptor expressed during early B-cell development, is reinduced during plasma-cell differentiation. High CD93/CD138 expression was restricted to antibody-secreting cells both in T-dependent and T-independent responses as naive, memory, and germinal-center B cells remained CD93-negative. CD93 was expressed on (pre)plasmablasts/plasma cells, including long-lived plasma cells that showed decreased cell cycle activity, high levels of isotype-switched Ig secretion, and modification of the transcriptional network. T-independent and T-dependent stimuli led to re-expression of CD93 via 2 pathways, either before or after CD138 or Blimp-1 expression. Strikingly, while humoral immune responses initially proceeded normally, CD93-deficient mice were unable to maintain antibody secretion and bone-marrow plasma-cell numbers, demonstrating that CD93 is important for the maintenance of plasma cells in bone marrow niches.

Cannabis and benzodiazepines as determinants of methadone trough plasma concentration variability in maintenance treatment: a transnational study.

PURPOSE: To assess tobacco, alcohol, cannabis and benzodiazepine use in methadone maintenance treatment (MMT) as potential sources of variability in methadone pharmacokinetics. METHODS: Trough plasma (R)- and (S)-methadone concentrations were measured on 77 Australian and 74 Swiss MMT patients with no additional medications other than benzodiazepines. Simple and multiple regression analyses were performed for the primary metric, plasma methadone concentration/dose. RESULTS: Cannabis and methadone dose were significantly associated with lower 24-h plasma (R)- and (S)-methadone concentrations/dose. The models containing these variables explained 14-16% and 17-25% of the variation in (R)- and (S)-methadone concentration/dose, respectively. Analysis of 61 patients using only CYP3A4 metabolised benzodiazepines showed this class to be associated with higher (R)-concentration/dose, which is consistent with a potential competitive inhibition of CYP3A4. CONCLUSION: Cannabis use and higher methadone doses in MMT could in part be a response to-or a cause of-more rapid methadone clearance. The effects of cannabis and benzodiazepines should be controlled for in future studies on methadone pharmacokinetics in MMT.

Maintenance of ancestral sex chromosomes in Palearctic tree frogs: direct evidence from Hyla orientalis.

Contrasting with the situation found in birds and mammals, sex chromosomes are generally homomorphic in poikilothermic vertebrates. This homomorphy was recently shown to result from occasional X-Y recombinations (not from turnovers) in several European species of tree frogs (Hyla arborea, H. intermedia and H. molleri). Because of recombination, however, alleles at sex-linked loci were rarely diagnostic at the population level; support for sex linkage had to rely on multilocus associations, combined with occasional sex differences in allelic frequencies. Here, we use direct evidence, obtained from anatomical and histological analyses of offspring with known pedigrees, to show that the Eastern tree frog (H. orientalis) shares the same pair of sex chromosomes, with identical patterns of male heterogamety and complete absence of X-Y recombination in males. Conservation of an ancestral pair of sex chromosomes, regularly rejuvenated via occasional X-Y recombination, seems thus a widespread pattern among Hyla species. Sibship analyses also identified discrepancies between genotypic and phenotypic sex among offspring, associated with abnormal gonadal development, suggesting a role for sexually antagonistic genes on the sex chromosomes.