Metabolite profiling of foslevodopa/foscarbidopa in plasma of healthy human participants by LC-HRMS indicates no major differences compared to administration of levodopa/carbidopa intestinal gel

Analysis was conducted to compare levodopa/carbidopa pharmacokinetics and drug-related material in plasma of healthy participants after receiving a continuous infusion of Levodopa/Carbidopa Intestinal Gel (LCIG) to a continuous subcutaneous infusion of foslevodopa/foscarbidopa. Study samples were from a randomized, open-label, 2-period crossover study in 20 healthy participants. Participants received either 24-h foslevodopa/foscarbidopa SC infusion to the abdomen or LCIG delivered for 24 h to the jejunum through a nasogastric tube with jejunal extension. Serial blood samples were collected for PK. Comparability of the LD PK parameters between the two treatment regimens was determined. Selected plasma samples were pooled per treatment group and per time point for metabolite profiling. LC-MSn was performed using high-resolution mass spectrometry to identify drug-related material across the dosing regimens and time points. The LD PK parameter central values and 90% confidence intervals following the foslevodopa/foscarbidopa subcutaneous infusion were between 0.8 and 1.25 relative to the LCIG infusion. With LCIG administration, LD, CD, 3-OMD, DHPA, DOPAC, and vanillacetic acid were identified in plasma at early and late time points (0.75 and 24 h); the metabolic profile after administration of foslevodopa/foscarbidopa demonstrated the same drug-related compounds with the exception of the administered foslevodopa. 3-OMD and vanillacetic acid levels increased over time in both treatment regimens. Relative quantification of LC-MS peak areas showed no major differences in the metabolite profiles. These results indicate that neither the addition of monophosphate prodrug moieties nor SC administration affects the circulating metabolite profile of foslevodopa/foscarbidopa compared to LCIG.

Comparison of PM2.5 Air Pollution Exposures and Health Effects Associations Using 11 Different Modeling Approaches in the Women's Health Initiative Memory Study (WHIMS)

BACKGROUND

Many approaches to quantifying air pollution exposures have been developed. However, the impact of choice of approach on air pollution estimates and health-effects associations remains unclear.

OBJECTIVES

Our objective is to compare particulate matter with aerodynamic diameter ≤ 2.5 μ m (PM 2.5 ) concentrations and resulting health effects associations using multiple estimation approaches previously used in epidemiologic analyses.

METHODS

We assigned annual PM 2.5 exposure estimates from 1999 to 2004 derived from 11 different approaches to Women's Health Initiative Memory Study (WHIMS) participant addresses within the contiguous US. Approaches included geostatistical interpolation approaches, land-use regression or spatiotemporal models, satellite-derived approaches, air dispersion and chemical transport models, and hybrid models. We used descriptive statistics and plots to assess relative and absolute agreement among exposure estimates and examined the impact of approach on associations between PM 2.5 and death due to natural causes, cardiovascular disease (CVD) mortality, and incident CVD events, adjusting for individual-level covariates and climate-based region.

RESULTS

With a few exceptions, relative agreement of approach-specific PM 2.5 exposure estimates was high for PM 2.5 concentrations across the contiguous US. Agreement among approach-specific exposure estimates was stronger near PM 2.5 monitors, in certain regions of the country, and in 2004 vs. 1999. Collectively, our results suggest but do not quantify lower agreement at local spatial scales for PM 2.5 . There was no evidence of large differences in health effects associations with PM 2.5 among estimation approaches in analyses adjusted for climate region.

CONCLUSIONS

Different estimation approaches produced similar spatial patterns of PM 2.5 concentrations across the contiguous US and in areas with dense monitoring data, and PM 2.5 -health effects associations were similar among estimation approaches. PM 2.5 estimates and PM 2.5 -health effects associations may differ more in samples drawn from smaller areas or areas without substantial monitoring data, or in analyses with finer adjustment for participant location. Our results can inform decisions about PM 2.5 estimation approach in epidemiologic studies, as investigators balance concerns about bias, efficiency, and resource allocation. Future work is needed to understand whether these conclusions also apply in the context of other air pollutants of interest. https://doi.org/10.1289/EHP12995.

The association of long-term exposure to criteria air pollutants, fine particulate matter components, and airborne trace metals with late-life brain amyloid burden in the Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND

Studies suggest associations between long-term ambient air pollution exposure and outcomes related to Alzheimer's disease (AD). Whether a link exists between pollutants and brain amyloid accumulation, a biomarker of AD, is unclear. We assessed whether long-term air pollutant exposures are associated with late-life brain amyloid deposition in Atherosclerosis Risk in Communities (ARIC) study participants.

METHODS

We used a chemical transport model with data fusion to estimate ambient concentrations of PM2.5 and its components, NO2, NOx, O3 (24-hour and 8-hour), CO, and airborne trace metals. We linked concentrations to geocoded participant addresses and calculated 10-year mean exposures (2002 to 2011). Brain amyloid deposition was measured using florbetapir amyloid positron emission tomography (PET) scans in 346 participants without dementia in 2012-2014, and we defined amyloid positivity as a global cortical standardized uptake value ratio ≥ the sample median of 1.2. We used logistic regression models to quantify the association between amyloid positivity and each air pollutant, adjusting for putative confounders. In sensitivity analyses, we considered whether use of alternate air pollution estimation approaches impacted findings for PM2.5, NO2, NOx, and 24-hour O3.

RESULTS

At PET imaging, eligible participants (N = 318) had a mean age of 78 years, 56% were female, 43% were Black, and 27% had mild cognitive impairment. We did not find evidence of associations between long-term exposure to any pollutant and brain amyloid positivity in adjusted models. Findings were materially unchanged in sensitivity analyses using alternate air pollution estimation approaches for PM2.5, NO2, NOx, and 24-hour O3.

CONCLUSIONS

Air pollution may impact cognition and dementia independent of amyloid accumulation, though whether air pollution influences AD pathogenesis later in the disease course or at higher exposure levels deserves further consideration.

Synthesis of self-renewing Fe(0)-dispersed ordered mesoporous carbon for electrocatalytic reduction of nitrates to nitrogen

In electrocatalytic reduction of nitrates to nitrogen, key issues are electrode activity, sustainable materials, preparation methods and cost. Herein, lignin, Fe³⁺ ion, and non-ionic surfactant were combined with evaporation-induced self-assembly (EISA) to prepare zero-valent Fe-dispersed ordered mesoporous carbon (OMC) electrode materials denoted as Fe#OMC. The method developed for preparing Fe-coordinated OMC material avoids the use of toxic phenols, aldehyde reagents and metal doping compounds. When synthesized Fe#OMC samples were applied as electrode materials for the electrocatalytic reduction of nitrate in aqueous solutions, maximum nitrate nitrogen removal was as high as 5373 mg N·g^-1 Fe from aqueous solutions containing 400 mg·L^-1 NO₃^--N, while nitrogen selectivity was close to 100%, exceeding catalytic performance of comparable materials. Active hydrogen produced by electrolysis of water during the reaction re-reduced Fe ions formed in the OMC material and stabilized Fe#OMC electrode performance and recycle. The Fe#OMC electrode is self-renewing with respect to its Fe zero-valent state, is simple to prepare from sustainable materials and is effective for electrocatalytic reduction of nitrate or nitrogen-containing compounds in water.

The Associations of Dietary Copper With Cognitive Outcomes

Dietary copper intake may be associated with cognitive decline and dementia. We used data from 10,269 participants of the Atherosclerosis Risks in Communities Study to study the associations of dietary copper intake with 20-year cognitive decline and incident dementia. Dietary copper intake from food and supplements was quantified using food frequency questionnaires. Cognition was assessed using 3 cognitive tests at study visits; dementia was ascertained at study visits and via surveillance. Multiple imputation by chained equations was applied to account for the missing information of cognitive function during follow-up. Survival analysis with parametric models and mixed-effect models were used to estimate the associations for incident dementia and cognitive decline, respectively. During 20 years of follow-up (1996-1998 to 2016-2017), 1,862 incident cases of dementia occurred. Higher intake of dietary copper from food was associated with higher risk of incident dementia among those with high intake of saturated fat (hazard ratio = 1.49, 95% confidence interval: 1.04, 1.95). Higher intake of dietary copper from food was associated with greater decline in language overall (beta = -0.12, 95% confidence interval: -0.23, -0.02). Therefore, a diet high in copper, particularly when combined with a diet high in saturated fat, may increase the risk of cognitive impairment.

Effects of Climate on the Variation in Abundance of Three Tick Species in Illinois

The range of ticks in North America has been steadily increasing likely, in part, due to climate change. Along with it, there has been a rise in cases of tick-borne disease. Among those medically important tick species of particular concern are Ixodes scapularis Say (Acari: Ixodidae), Dermacentor variabilis Say (Acari: Ixodidae), and Amblyomma americanum Linneaus (Acari: Ixodidae). The aim of this study was to determine if climate factors explain existing differences in abundance of the three aforementioned tick species between two climatically different regions of Illinois (Central and Southern), and if climate variables impact each species differently. We used both zero-inflated regression approaches and Bayesian network analyses to assess relationships among environmental variables and tick abundance. Results suggested that the maximum average temperature and total precipitation are associated with differential impact on species abundance and that this difference varied by region. Results also reinforced a differential level of resistance to desiccation among these tick species. Our findings help to further define risk periods of tick exposure for the general public, and reinforce the importance of responding to each tick species differently.

Characteristics of movers and predictors of residential mobility in the Atherosclerosis Risk in Communities (ARIC) cohort

Current efforts to characterize movers and identify predictors of moving have been limited. We used the ARIC cohort to characterize non-movers, short-distance movers, and long-distance movers, and employed best subset algorithms to identify important predictors of moving, including interactions between characteristics. Short- and long-distance movers were notably different from non-movers, and important predictors of moving differed based on the distance of the residential move. Importantly, systematic inclusion of interaction terms enhanced model fit and was substantively meaningful. This work has important implications for epidemiologic studies of contextual exposures and those treating residential mobility as an exposure.

A new measure to understand the role of science in US Congress: lessons learned from the Legislative Use of Research Survey (LURS)

BACKGROUND

There is growing interest in and recognition of the need to use scientific evidence to inform policymaking. However, many of the existing studies on the use of research evidence (URE) have been largely qualitative, and the majority of existing quantitative measures are underdeveloped or were tested in regional or context-dependent settings. We are unaware of any quantitative measures of URE with national policymakers in the US.

AIMS AND OBJECTIVES

Explore how to measure URE quantitatively by validating a measure of congressional staff's attitudes and behaviors regarding URE, the Legislative Use of Research Survey (LURS), and by discussing the lessons learned through administering the survey.

METHODS

A 68-item survey was administered to 80 congressional staff to measure their reported research use, value of research, interactions with researchers, general information sources, and research information sources. Confirmatory factor analyses were conducted on each of these five scales. We then trimmed the number of items, based on a combination of poor factor loadings and theoretical rationale, and ran the analyses on the trimmed subscales.

FINDINGS

We substantially improved our model fits for each scale over the original models and all items had acceptable factor loadings with our trimmed 35-item survey. We also describe the unique set of challenges and lessons learned from surveying congressional staff.

DISCUSSION AND CONCLUSIONS

This work contributes to the transdisciplinary field of URE by offering a tool for studying the mechanisms that can bridge research and policy and shedding light into best practices for measuring URE with national policymakers in the US.

Duration of skin desensitisation following palmar digital nerve blocks with lidocaine, bupivacaine, mepivacaine and prilocaine

Objective comparative evidence of the time to onset and duration of effect provided by local anaesthetic (LA) agents for perineural blocks in the horse is lacking. Clear knowledge of these properties is required to guide clinically appropriate agent selection and aid interpretation of response to diagnostic blocks for lameness examinations. An interventional study, with complete, randomised crossover design was used to compare time to onset and duration of skin desensitisation provided by four LA agents applied to palmar digital nerve blocks in 12 horses. Effect at each time point was determined using a pressure gauge to measure the mechanical nociceptive threshold (MNT) over the heel bulbs. Complete desensitisation was defined when MNT was greater than four times the pre-block baseline. Onset and duration of complete desensitisation were recorded and compared across agents using a mixed linear model. When significant (P ≤ 0.05), post-hoc paired comparisons between agents were performed against a Tukey's corrected P ≤ 0.05. Onset of complete skin desensitisation for each agent was <5 min. Duration for lidocaine (mean 25 min; 95% confidence interval [CI] 9-42) was shorter than bupivacaine (53 min; 95% CI 39-65), which was shorter than both prilocaine (102 min; 95% CI 81-123) and mepivacaine (107 min; 95% CI 92-121), which were not different. Although onset of complete skin desensitisation was not different for the LA agents tested, duration varied from 25 min to nearly 2 h. Prilocaine and mepivacaine provided the most prolonged duration of effect, both exceeding bupivacaine.

Nitrogen biogeochemistry in a boreal headwater stream network in interior Alaska

High latitude, boreal watersheds are nitrogen (N)-limited ecosystems that export large amounts of organic carbon (C). Key controls on C cycling in these environments are the biogeochemical processes affecting the N cycle. A study was conducted in Nome Creek, an upland tributary of the Yukon River, and two headwater tributaries to Nome Creek, to examine the relation between seasonal and transport-associated changes in C and N pools and N-cycling processes using laboratory bioassays of water and sediment samples and in-stream tracer tests. Dissolved organic nitrogen (DON) exceeded dissolved inorganic nitrogen (DIN) in Nome Creek except late in the summer season, with little variation in organic C:N ratios with time or transport distance. DIN was dominant in the headwater tributaries. Rates of organic N mineralization and denitrification in laboratory incubations were positively correlated with sediment organic C content, while nitrification rates differed greatly between two headwater tributaries with similar drainages. Additions of DIN or urea did not stimulate microbial activity. In-stream tracer tests with nitrate and urea indicated that uptake rates were slow relative to transport rates; simulated rates of uptake in stream storage zones were higher than rates assessed in the laboratory bioassays. In general, N-cycle processes were more active and had a greater overall impact in the headwater tributaries and were minimized in Nome Creek, the larger, higher velocity, transport-dominated stream. Given expectations of permafrost thaw and increased hydrologic cycling that will flush more inorganic N from headwater streams, our results suggest higher N loads from these systems in the future.

0343 Associations of Endogenous Hormones and Phthalate Exposure with Subjective and Objective Sleep Measures in Midlife Women

Introduction

Impaired sleep during the menopausal transition reduces quality of life and increases risk of multiple diseases. The changing hormonal milieu during midlife is associated with impaired sleep. Endocrine disrupting chemicals, such as phthalates, may also contribute to the increased prevalence of sleep disturbances in midlife women. Phthalates are known to impact the endogenous hormones associated with sleep. However, the link between phthalate exposure and sleep quality remains unexplored.

Methods

We recruited 26 midlife women (median age 50 years) through the Carle Regional Sleep Disorders Center in Urbana, Illinois. Subjective sleep was assessed through the Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, and self-reported frequency of sleep disturbances, insomnia, and restless sleep. Objective sleep was measured using actigraphy and manual sleep logs (7-day average). Serum levels of follicle-stimulating hormone, estradiol, progesterone, testosterone, free estradiol, and free testosterone were quantified using ELISAs from a single sample from each participant. Phthalate metabolites were quantified from urine using high performance liquid chromatography-mass spectrometry (HPLC-MS). Covariates, including depression, hot flashes, quality of life, demographics, and lifestyle factors, were measured via surveys.

Results

Preliminary unadjusted logistic regression was used to determine the association between hormone values and subjective sleep quality binomial variables, including daytime sleepiness, sleep efficiency, sleep onset latency, sleep duration, number of sleep disturbances, and frequency of sleep disturbances. Each of these subjective sleep measures is significantly associated with one or more hormones.

Conclusion

Our results are consistent with literature identifying associations between hormones and subjective sleep in midlife women. Additional analyses will determine associations between hormones and objective sleep, and phthalates with both subjective and objective sleep measures. Excitingly, our study will be among the first to investigate the association between endocrine disruption and sleep quality in this population.

Support

Carle Illinois Seed Grant Program

Irrigation fluid volume requirement for conventional arthrocentesis of the temporomandibular joint: a cadaver study

Temporomandibular joint (TMJ) arthrocentesis is considered an effective and minimally invasive procedure for certain conditions related to temporomandibular disorders. The ideal irrigation volume for arthrocentesis lavage has not yet been defined. Therefore, the aim of this study was to evaluate the efficacy of different saline solution volumes in removing methylene blue from the TMJ space of fresh human cadavers. Nineteen cadavers were selected and 1ml of 10μM methylene blue solution was injected into the upper joint space unilaterally. Conventional arthrocentesis was then conducted by infusion of 300ml of 0.9% saline solution, collecting a 1-ml sample from the drained quantity for every 25ml injected. Finally, the samples were assayed by measuring photo absorbance of the methylene blue solution. There was a statistically significant difference between the irrigation volumes regarding the removal of methylene blue solution from the joint space (P<0.001), specifically between the first 25 ml and 200 ml (P=0.014), 225 ml (P=0.001), 250 ml (P<0.001), and 275 ml (P=0.001). Based on this ex vivo study, a 25-ml perfusion volume appears to be sufficient for joint lavage in conventional arthrocentesis of the TMJ.

Ranking disease control strategies with stochastic outcomes

This paper explains how the methodologies of first and second order stochastic dominance, and expected utility using specific risk preferences, can be applied to epidemiology when choosing among control strategies that have stochastic outcomes. We provide a step-by-step guide on how epidemiologists can rank a number of control strategies based on their distribution of estimated benefits. We also explain how the expected utility model and decision maker's risk preferences can be used to select between outcomes when none stochastically dominates. To illustrate these techniques, we show the ranking of various control strategies for a dairy herd endemically infected with Mycobacterium avium subs. paratuberculosis (MAP) and mastitis, and explain how decision maker's risk preferences affect the ranking.

Black liquor-derived calcium-activated biochar for recovery of phosphate from aqueous solutions

Black liquor-derived calcium-activated biochars (Ca-biochar) were synthesized by treating rice straw with Ca(OH)₂ to create an adsorbent that was effective for removing phosphate from aqueous waste streams. The Ca(OH)₂ acts to separate lignin from the biomass, create pores in the biochar solids and form active adsorption sites. The Ca-biochar adsorbent was efficient for the removal of phosphate from aqueous solutions (pH 1.0 to pH 13.0) with a highest phosphate adsorption capacity of 197 mg/g. Phosphate adsorption was correlated with pseudo-second-order kinetics and the Langmuir model with primary mechanisms being attributed to chemical precipitation and ligand exchange. Application of the Ca-biochar (0.2 g/L) to actual wastewater from a cattle farm (phosphorus content 3.78 mg/L) reduced the phosphorus content to 0.021 mg/L. This work utilizes waste black liquor to prepare functionalized biochar materials, providing a promising approach for black liquor reuse and phosphate removal and recovery from phosphorus-rich waste streams.

Methane and nitrous oxide temporal and spatial variability in two midwestern USA streams containing high nitrate concentrations

Concentrations and emissions of greenhouse gases CO₂, CH₄, and N₂O commonly are examined individually in aquatic environments in which each is expected to be relatively important; however, their co-occurrence and dynamic interactions in fluvial settings could provide important information about their controlling biogeochemical processes and potential contributions to global climate change. Spatial and temporal variability of CH₄, N₂O, and CO₂ concentrations were measured from June 1999 to September 2003 in two nitrate-rich (40-1200 μM) streams draining agricultural land in the midwestern USA that differed ~13-fold in flow. Seasonal (biweekly), diel (hourly), and transport-oriented (reach-scale) sampling approaches were compared. Dissolved gas concentrations exceeded atmospheric equilibrium values up to 700- and 16-fold, for CH₄ and N₂O, respectively. Mean concentrations were higher in the larger stream than in the smaller stream. In both streams, CH₄ emissions were generally higher in summer-fall and negatively correlated with flow and NO₃^- concentration while N₂O emissions were generally higher in winter/spring and positively correlated with flow and NO₃^-. In the small stream, diel variations in the concentrations, emissions, and isotopic compositions of CH₄, N₂O, and NO₂^- resulted from diel variations in sources, sinks, and air-water gas exchange velocities. Seasonal mean total (CH₄ + N₂O) area-normalized emission rates, expressed as CO₂ warming potential equivalents, were similar for the two streams, but the total reach-scale emission rate for the larger stream, including CO₂, was about 2.9 times that of the smaller stream (131.6 vs 46.0 kg CO₂ equivalents km^-1 day^-1, respectively). The CH₄ contribution to this flux was 9-28%, despite the relatively high NO₃^- and O₂ concentrations in the streams, indicating contributions from upwelling groundwater or reactions in streambed sediment.

School start times and teenage driver motor vehicle crashes

INTRODUCTION

Shifting school start times to 8:30 am or later has been found to improve academic performance and reduce behavior problems. Limited research suggests this may also reduce adolescent driver motor vehicle crashes. A change in the school start time from 7:30 am to 8:45 am for all public high schools in one North Carolina county presented the opportunity to address this question with greater methodologic rigor.

METHOD

We conducted ARIMA interrupted time-series analyses to examine motor vehicle crash rates of high school age drivers in the intervention county and 3 similar comparison counties with comparable urban-rural population distribution. To focus on crashes most likely to be affected, we limited analysis to crashes involving 16- & 17-year-old drivers occurring on days when school was in session.

RESULTS

In the intervention county, there was a 14% downward shift in the time-series following the 75 min delay in school start times (p = .076). There was no change approaching statistical significance in any of the other three counties. Further analysis indicated marked, statistically significant shifts in hourly crash rates in the intervention county, reflecting effects of the change in school start time on young driver exposure. Crashes from 7 to 7:59 am decreased sharply (-25%, p = .008), but increased similarly from 8 to 8:59 am (21%, p = .004). Crashes from 2 to 2:59 pm declined dramatically (-48%, p = .000), then increased to a lesser degree from 3 to 3:59 pm (32%, p = .024) and non-significantly from 4 to 4:59 (19%, p = .102). There was no meaningful change in early morning or nighttime crashes, when drowsiness-induced crashes might have been expected to be most common.

DISCUSSION

The small decrease in crashes among high school age drivers following the shift in school start time is consistent with the findings of other studies of teen driver crashes and school start times. All these studies, including the present one, have limitations, but the similar findings suggest that crashes and school start times are indeed related, with earlier start times equating to more crashes.

CONCLUSION

Later high school start times (>8:30 am) appear to be associated with lower adolescent driver crash rates, but additional research is needed to confirm this and to identify the mechanism by which this occurs (reduced drowsiness or reduced exposure).

Constraining the Oxygen Isotopic Composition of Nitrate Produced by Nitrification

Measurements of the stable isotope ratios of nitrogen (¹⁵N/¹⁴N) and oxygen (¹⁸O/¹⁶O) in nitrate (NO₃^-) enable identification of sources, dispersal, and fate of natural and contaminant NO₃^- in aquatic environments. The ¹⁸O/¹⁶O of NO₃^- produced by nitrification is often assumed to reflect the proportional contribution of oxygen atom sources, water, and molecular oxygen, in a 2:1 ratio. Culture and seawater incubations, however, indicate oxygen isotopic equilibration between nitrite (NO₂^-) and water, and kinetic isotope effects for oxygen atom incorporation, which modulate the NO₃^{- 18}O/¹⁶O produced during nitrification. To investigate the influence of kinetic and equilibrium effects on the isotopic composition of NO₃^- produced from the nitrification of ammonia (NH₃), we incubated streamwater supplemented with ammonium (NH₄⁺) and increments of ¹⁸O-enriched water. Resulting NO₃^{- 18}O/¹⁶O ratios showed (1) a disproportionate sensitivity to the ¹⁸O/¹⁶O ratio of water, mediated by isotopic equilibration between water and NO₂^-, as well as (2) kinetic isotope discrimination during O atom incorporation from molecular oxygen and water. Empirically, the NO₃^{- 18}O/¹⁶O ratios thus produced fortuitously converge near the ¹⁸O/¹⁶O ratio of water. More elevated NO₃^{- 18}O/¹⁶O values commonly reported in soils and oxic groundwater may thus derive from processes additional to nitrification, including NO₃^- reduction.

Thalidomide-type teratogenicity: structure-activity relationships for congeners

Unravelling the molecular basis of thalidomide embryotoxicity, which is remarkably species-specific, is challenging in view of its low toxicity in the mature animal. Employing data derived solely from proven sensitive primate species or susceptible strains of rabbit, the structure-activity relationship of over 50 compounds which are, arguably, congeners of thalidomide has been reviewed. The molecular requirement for 'thalidomide-type' teratogenicity was highly structure dependent. Both the phthalimide and glutarimide groups were essential for embryopathic activity, although minor substitutions in either or both rings could be tolerated without a loss of toxicity. An α-linkage between the two cyclic structures was essential; a β-link resulted in a complete loss of embryopathic activity. Crucially, this α-configuration provided a centre of asymmetry enabling the existence of stereoisomers. The thalidomide molecule is not a static entity and under physiological conditions it undergoes a number of intra- and inter-molecular reactions. Besides irreversible hydrolysis, its keto-enol tautomerism, base-assisted proton transfer and glutarimide ring rotation lead to rapid interconversion of the thalidomide enantiomers. These enantiomers form equilibria between themselves and also between both homochiral and heterochiral dimers. It is proposed that the more energetically favourable and stable heterochiral dimer of thalidomide is an active agent that possesses the structural features of the paired nucleotides of the double-stranded DNA. Its capacity to enter into hydrogen bonding interactions affects DNA expression in a chaotic manner without causing permanent mutations. This disruption may well be concentrated at nucleotide sites known to be involved in specific promoter regions of the genome.

The reliability of identifying the Omega sign using axial T2-weighted magnetic resonance imaging

Preoperative identification of the eloquent brain is important for neurosurgical planning. One common method of finding the motor cortex is by localizing "the Omega sign." No studies have tested the reliability of imaging to identify the Omega sign. We identified 40 recent and consecutive patients who had undergone preoperative functional magnetic resonance imaging for identification of the hand motor area prior to tumor resection. We recruited 11 neurosurgical residents of various levels of training and one board-certified neurosurgeon to identify the hand motor cortex Omega. Testees were given axial images of T2-weighted MRI and placed marks where they expected to find the Omega. Two board-certified radiologists graded and quantified the localization attempts. Inter-rater reliability was assessed using the kappa statistic, and Rao-Scott chi-square tests were used to examine the relationship between clinical factors and testees' experience with correct identification of the Omega sign. The overall correct identification rate was 69.9% (95% CI = 63.4-75.7), ranging from 36.6% to 92.7% among all raters for the tumor side and from 46.2% to 97.4% for the non-tumor side. Anatomic distortion greatly affected correct identification ( p < 0.005). Senior residents had a significantly higher rate of identification of the Omega than junior residents ( p < 0.001). Overall, inter-rater reliability for the Omega sign is poor, with a Fleiss kappa of 0.23. We concluded that correct identification of the Omega sign is affected by tumor distortion and experience but overall is not reliable. This underscores the limitations of anatomic landmarks and the importance of utilizing multiple scanning planes and preoperative fMRI for appropriate localization.

Alane adsorption and dissociation on the Si(0 0 1) surface

We used DFT to study the energetics of the decomposition of alane, AlH₃, on the Si(0 0 1) surface, as the acceptor complement to PH₃. Alane forms a dative bond with the raised atoms of silicon surface dimers, via the Si atom lone pair. We calculated the energies of various structures along the pathway of successive dehydrogenation events following adsorption: AlH₂, AlH and Al, finding a gradual, significant decrease in energy. For each stage, we analyse the structure and bonding, and present simulated STM images of the lowest energy structures. Finally, we find that the energy of Al atoms incorporated into the surface, ejecting a Si atom, is comparable to Al adatoms. These findings show that Al incorporation is likely to be as precisely controlled as P incorporation, if slightly less easy to achieve.

Use of an Individual-based Model to Control Transmission Pathways of Mycobacterium avium Subsp. paratuberculosis Infection in Cattle Herds

Johne’s disease (JD) is a chronic enteric disease in cattle caused by Mycobacterium avian subsp. paratuberculosis (MAP). Eradicating JD is a difficult task due to the long incubation period of MAP, inefficient diagnostic tests, and delayed clinical signs. Effective control strategies can help farmers to reduce prevalence, but those most acceptable to farmers combine specific information about lactation performance and testing results, which existing models do not provide. This paper presents an individual-based model of MAP infection dynamics and assesses the relative performance of the applied alternative control strategies. The base dairy herd model included the daily life events of a dairy cow and reflects several current dairy management processes. We then integrated MAP infection dynamics into the model. The model adopted four different test-based control strategies based on risk-based culling decisions and three hygiene scenarios. The model tracked the source of each infection and quantified the efficacy of each control strategy in reducing the risks of different transmission routes. The results suggest that risk-based culling can reduce prevalence compared with no control, but cannot eliminate the infection. Overall, this work provides not only a valuable tool to investigate MAP transmission dynamics but also offers adaptability to model similar infectious diseases.

The effect of Mycobacterium avium ssp. paratuberculosis infection on clinical mastitis occurrence in dairy cows

Endemic diseases can be counted among the most serious sources of losses for livestock production. In dairy farms in particular, one of the most common diseases is Johne's disease, caused by Mycobacterium avium ssp. paratuberculosis (MAP). Infection with MAP causes direct costs because it affects milk production, but it has also been suspected to increase the risk of clinical mastitis (CM) among infected animals. This might contribute to further costs for farmers. We asked whether MAP infection represents a risk factor for CM and, in particular, whether CM occurrences were more common in MAP-infected animals. Our results, obtained by survival analysis, suggest that MAP-infected cows had an increased probability of experiencing CM during lactation. These results highlight the need to account for the interplay of infectious diseases and other health conditions in economic and epidemiological modeling. In this case, accounting for MAP-infected cows having an increased CM occurrence might have nonnegligible effects on the estimated benefit of MAP control.

Nutrient recycle from defatted microalgae (Aurantiochytrium) with hydrothermal treatment for microalgae cultivation

Defatted heterotrophic microalgae (Aurantiochytrium limacinum SR21) was treated with high temperature water (175-350°C, 10-90min) to obtain nitrogen and phosphorous nutrients as a water soluble fraction (WS). Yields of nitrogen and phosphorous recovered in WS varied from 38 to 100% and from 57 to 99%, respectively. Maximum yields of nitrogen containing compounds in WS were proteins (43%), amino acids (12%) and ammonia (60%) at treatment temperatures of 175, 250 and 350°C, respectively. Maximum yield of phosphorous in WS was 99% at a treatment temperature of 250°C. Cultivation experiments of microalgae (A. limacinum SR21) using WS obtained at 200 and 250°C showed positive growth. Water soluble fractions from hydrothermal treatment of defatted microalgae are effective nitrogen and phosphorous nutrient sources for microalgae cultivation.

Economic consequences of paratuberculosis control in dairy cattle: A stochastic modeling study

The cost of paratuberculosis to dairy herds, through decreased milk production, early culling, and poor reproductive performance, has been well-studied. The benefit of control programs, however, has been debated. A recent stochastic compartmental model for paratuberculosis transmission in US dairy herds was modified to predict herd net present value (NPV) over 25 years in herds of 100 and 1000 dairy cattle with endemic paratuberculosis at initial prevalence of 10% and 20%. Control programs were designed by combining 5 tests (none, fecal culture, ELISA, PCR, or calf testing), 3 test-related culling strategies (all test-positive, high-positive, or repeated positive), 2 test frequencies (annual and biannual), 3 hygiene levels (standard, moderate, or improved), and 2 cessation decisions (testing ceased after 5 negative whole-herd tests or testing continued). Stochastic dominance was determined for each herd scenario; no control program was fully dominant for maximizing herd NPV in any scenario. Use of the ELISA test was generally preferred in all scenarios, but no paratuberculosis control was highly preferred for the small herd with 10% initial prevalence and was frequently preferred in other herd scenarios. Based on their effect on paratuberculosis alone, hygiene improvements were not found to be as cost-effective as test-and-cull strategies in most circumstances. Global sensitivity analysis found that economic parameters, such as the price of milk, had more influence on NPV than control program-related parameters. We conclude that paratuberculosis control can be cost effective, and multiple control programs can be applied for equivalent economic results.

DOSE AND GAMMA-RAY SPECTRA FROM NEUTRON-INDUCED RADIOACTIVITY IN MEDICAL LINEAR ACCELERATORS FOLLOWING HIGH-ENERGY TOTAL BODY IRRADIATION

Production of radioisotopes in medical linear accelerators (linacs) is of concern when the beam energy exceeds the threshold for the photonuclear interaction. Staff and patients may receive a radiation dose as a result of the induced radioactivity in the linac. Gamma-ray spectroscopy was used to identify the isotopes produced following the delivery of 18 MV photon beams from a Varian 21EX and an Elekta Synergy. The prominent radioisotopes produced include ¹⁸⁷W, ⁶³Zn, ⁵⁶Mn, ²⁴Na and ²⁸Al in both linac models. The dose rate was measured at the beam exit window (12.6 µSv in the first 10 min) following 18 MV total body irradiation (TBI) beams. For a throughput of 24 TBI patients per year, staff members are estimated to receive an annual dose of up to 750 μSv at the patient location. This can be further reduced to 65 μSv by closing the jaws before re-entering the treatment bunker.

In Defense of the Attitudes toward Women Scale: An Affirmation of Validity and Reliability

Numerous references were found as positive evidence of construct validity, criterion validity, and reliability for Attitudes Toward Women Scale. New separate factor analytic studies of the 55-item scale and of its 25-item short form were performed to evaluate and extend previous construct validations. Contrary to earlier reports of structural analysis, an administration of the scale to 208 female and 243 male tennis players yielded only one major factor, accounting for 22% of the total variance. An administration of the 25-item scale to 293 male and 258 female university students also yielded one major factor accounting for 30% and 23% of the total variance, respectively. Separate reliability analyses over female and male subjects yielded alphas of .93 for the 55-item scale and .86 and .90, respectively, for the 25-item scale. A Pearson correlation between the short and long forms produced a coefficient of .99. Recently reported doubts about the instrument's validity were groundless.

Factor Validation and Refinement of the Sex-Role Questionnaire and its Relationship to the Attitudes toward Women Scale

Separate factor analytic studies of the 82-item Sex-role Questionnaire and of its original 38 stereotypic items were performed to evaluate and extend previous structural analyses. The 82-item questionnaire and the 55-item Attitudes Toward Women Scale were administered to 208 female and 243 male tennis players. Results yielded three orthogonal Sex-role Questionnaire factors accounting for 33% of the total variance. This structure also held for the 38 stereotypic items. Loadings on an unrotated first principal axis yielded a description of Social Desirability. After rotation, variance spread to an Assertiveness Factor (10%), a Sensitivity Factor (12%), and a Rationality Factor (11%). From these factors were derived three highly reliable 15-item scales. The three scales combined to produce a refined 45-item Sex-role Questionnaire with an over-all reliability alpha of .83. The correlation between the 82-item instrument total score and the 55-item attitude scale total score was a low .25. The common variance was primarily attributable to the relationship between the Attitudes Toward Women Scale and the Sensitivity Factor. This relationship was enhanced little by refinement of the Sex-role Questionnaire.

Prolactin and Impotence in Diabetes Mellitus

A study was undertaken to determine whether impotence in some diabetic patients might be due to a coincidental prolactinoma and therefore be potentially treatable. Of 83 consecutive men attending a diabetic clinic, three were found to have persistent mild to moderate hyperprolactinaemia. None of the three was impotent or taking any drug known to be associated with elevated serum prolactin, and anterior pituitary responses and pituitary fossa tomograms did not reveal any abnormality. The mean serum prolactin concentration of the 37 insulin-treated men was not significantly different from that of the 46 men on diet with or without anti-diabetic tablets, nor was there any significant difference between the mean serum prolactin concentrations of the 19 impotent men and of the 64 non-impotent men.

Large deviations of tail estimators based on the Pareto approximation

We consider the relative error of a tail function when this is approximated by y–α using an estimator of Hill's for α. The results combine recent work of Davis and Resnick on tail estimation with Anderson's work on large deviations in extreme-value theory. Treating separately the domains of attraction of Φα and Λ, we obtain general conditions for the relative error to tend to 0 as u →∞, y → ∞ simultaneously. The results serve as warning against the automatic extrapolation of estimates based on extreme-value approximations.

The extremal index for a Markov chain

The paper presents a method of computing the extremal index for a discrete-time stationary Markov chain in continuous state space. The method is based on the assumption that bivariate margins of the process are in the domain of attraction of a bivariate extreme value distribution. Scaling properties of bivariate extremes then lead to a random walk representation for the tail behaviour of the process, and hence to computation of the extremal index in terms of the fluctuation properties of that random walk. The result may then be used to determine the asymptotic distribution of extreme values from the Markov chain.

The behavior of multivariate maxima of moving maxima processes

In the characterization of multivariate extremal indices of multivariate stationary processes, multivariate maxima of moving maxima processes, or M4 processes for short, have been introduced by Smith and Weissman. Central to the introduction of M4 processes is that the extreme observations of multivariate stationary processes may be characterized in terms of a limiting max-stable process under quite general conditions, and that a max-stable process can be arbitrarily closely approximated by an M4 process. In this paper, we derive some additional basic probabilistic properties for a finite class of M4 processes, each of which contains finite-range clustered moving patterns, called signature patterns, when extreme events occur. We use these properties to construct statistical estimation schemes for model parameters.

Limit theorems and approximations for the reliability of load-sharing systems

Techniques for studying the reliability of simple series or parallel systems are well known. This paper is concerned with more complicated systems in which the load on failed elements is transmitted to unfailed elements according to some load-sharing rule. The emphasis is on local load sharing, and in particular on a specific load-sharing rule introduced by Harlow and Phoenix for fibrous composites. Earlier results are reviewed and improved techniques for approximating the probability of failure and the size effect are derived.

Uniform rates of convergence in extreme-value theory

Rates of convergence are derived for the convergence in distribution of renormalised sample maxima to the appropriate extreme-value distribution. Related questions which are discussed include the estimation of the principal error term and the optimality of the renormalising constants. Throughout the paper a close parallel is drawn with the theory of slow variation with remainder. This theory is used in proving most of the results. Some applications are discussed, including some models of importance in reliability.

A counterexample concerning the extremal index

The concept of an extremal index, which is a measure of local dependence amongst the exceedances over a high threshold by a stationary sequence, has a natural interpretation as the reciprocal of mean cluster size. We exhibit a counterexample which shows that this interpretation is not necessarily correct.

Hydrologic Controls on Nitrogen Cycling Processes and Functional Gene Abundance in Sediments of a Groundwater Flow-Through Lake

The fate and transport of inorganic nitrogen (N) is a critically important issue for human and aquatic ecosystem health because discharging N-contaminated groundwater can foul drinking water and cause algal blooms. Factors controlling N-processing were examined in sediments at three sites with contrasting hydrologic regimes at a lake on Cape Cod, MA. These factors included water chemistry, seepage rates and direction of groundwater flow, and the abundance and potential rates of activity of N-cycling microbial communities. Genes coding for denitrification, anaerobic ammonium oxidation (anammox), and nitrification were identified at all sites regardless of flow direction or groundwater dissolved oxygen concentrations. Flow direction was, however, a controlling factor in the potential for N-attenuation via denitrification in the sediments. Potential rates of denitrification varied from 6 to 4500 pmol N/g/h from the inflow to the outflow side of the lake, owing to fundamental differences in the supply of labile organic matter. The results of laboratory incubations suggested that when anoxia and limiting labile organic matter prevailed, the potential existed for concomitant anammox and denitrification. Where oxic lake water was downwelling, potential rates of nitrification at shallow depths were substantial (1640 pmol N/g/h). Rates of anammox, denitrification, and nitrification may be linked to rates of organic N-mineralization, serving to increase N-mobility and transport downgradient.

Antioxidation Properties and Surface Interactions of Polyvinylpyrrolidone-Capped Zerovalent Copper Nanoparticles Synthesized in Supercritical Water

Zerovalent copper nanoparticles (CuNPs) (diameter, 26.5 ± 9 nm) capped with polyvinylpyrrolidone (PVP) were synthesized in supercritical water at 400 °C and 30 MPa with a continuous flow reactor. The PVP-capped CuNPs were dispersed in distilled water, methanol, ethanol, 1-propanol, 2-propanol, butanol, and their mixed solvents to study their long-term stability. Temporal variation of UV-vis spectra and surface plasmon resonance were measured and showed that ethanol, the propanols, and butanol solvents provided varying degrees of oxidative protection for Cu(0). Fourier transform infrared spectroscopy showed that PVP adsorbed onto the surface of the CuNPs with a pyrrolidone ring of PVP even if the CuNPs were oxidized. Intrinsic viscosities of PVP were higher for solvents that provided antioxidation protection than those that give oxidized CuNPs. In solvents that provided Cu(0) with good oxidative protection (ethanol, the propanols, and butanol), PVP polymer chains formed large radii of gyration and coil-like conformations in the solvents so that they were arranged uniformly and orderly on the surface of the CuNPs and could provide protection of the Cu(0) surface against dissolved oxygen. In solvents that provided poor oxidative protection for Cu(0) (water, alcohol-water mixed solvents with 30% water), PVP polymer chains had globular-like conformations due to their relatively high hydrogen-bonding interactions and sparse adsorption onto the CuNP surface. Antioxidative properties of PVP-capped CuNPs in a solvent can be ascribed to the conformation of PVP polymer chains on the Cu(0) particle surface that originates from the interaction between polymer chains and its interaction with the solvent.

The views of parents who experience intergenerational poverty on parenting and play: a qualitative analysis

BACKGROUND

There is minimal literature on how parents experiencing intergenerational poverty view their role as parents and the value they place on children's play. The objective of this study was to examine how these parents view their parenting role and their beliefs about children's play.

METHODS

Thirteen mothers of preschool-aged children who experienced intergenerational poverty were recruited to the study. Semi-structured interviews were conducted and were analysed using interpretive phenomenological analysis.

RESULTS

Parents described their role as guiding their children to become 'good' people, to teach them skills and provide a routine within the home. There were two disconnections in the data including the view that whilst parenting was hard and lonely, it was also a private matter and participants preferred not to seek support. A second disconnection was in terms of their beliefs about play. Parents believed that whilst play was valuable to their child's development, it was not their role to play with children. However, if parents did play with their child, they noticed positive changes in their child's behaviour.

CONCLUSION

The views of parents who experienced intergenerational poverty were similar to other reported findings in parenting studies. However, the current sample differed on not seeking help for support as well as not seeing their role as playing with their children, even though occasions of joining their child in play were associated with a positive change in their relationship with their child. This has implications for communicating about parenting issues with parents who have experienced intergenerational poverty.