Inter-site Difference Research Articles

White matter characteristics in children with cerebral palsy prior to selective dorsal rhizotomy: a multicenter diffusion tensor imaging study.

The aims of this study were to 1) assess and quantify white matter (WM) microstructural characteristics derived from diffusion tensor imaging (DTI) in children with cerebral palsy (CP) prior to selective dorsal rhizotomy (SDR), and 2) investigate potential associations between WM diffusion properties and gross motor function and spasticity in children with spastic CP who underwent SDR. This study is a multisite study based on DT images acquired prior to SDR as well as postoperative outcome data. DTI data collected from two sites were harmonized using the ComBat approach to minimize intersite scanner difference. The DTI abnormalities between children with spastic CP and controls were analyzed and correlated with the severity of impaired mobility based on the Gross Motor Function Classification System (GMFCS). The improvement in gross motor function and spasticity after SDR surgery was assessed utilizing the Gross Motor Function Measure-66 (GMFM-66), the Modified Tardieu Scale (MTS), and the modified Ashworth scale (MAS). Alterations in these outcome measures were quantified in association with DTI abnormalities. Significant DTI alterations, including lower fractional anisotropy (FA) in the genu of the corpus callosum (gCC) and higher mean diffusivity (MD) in the gCC and posterior limb of the internal capsule (PLIC), were found in children in the SDR group when compared with the age-matched control group (all p < 0.05). Greater DTI alterations (FA in gCC and MD in gCC and PLIC) were associated with lower mobility levels as determined based on GMFCS level (p < 0.05). The pre- to post-SDR improvement in motor function based on GMFM-66 was statistically significant (p = 0.006 and 0.002 at 6-month and 12-month follow-ups, respectively). The SDR efficacy was also identified as improving spasticity in lower-extremity muscle groups assessed with the MTS and MAS. Partial correlation analysis presented a significant association between pre- to post-SDR MTS alteration and DTI abnormalities. The findings in the present study provided initial quantitative evidence to establish the WM microstructural characteristics in children with spastic CP prior to SDR surgery. The study generated data for the association between baseline DTI characteristics and mobility in children with CP prior to SDR surgery. The study also demonstrated SDR efficacy in improving motor function and spasticity based on the GMFM-66, MTS, and MAS, respectively, in association with DTI data.

Blinding efficacy and adverse events following repeated transcranial alternating current, direct current, and random noise stimulation

As transcranial electrical stimulation (tES) protocols advance, assumptions underlying the technique need to be retested to ensure they still hold. Whilst the safety of stimulation has been demonstrated mainly for a small number of sessions, and small sample size, adverse events (AEs) following multiple sessions remain largely untested. Similarly, whilst blinding procedures are typically assumed to be effective, the effect of multiple stimulation sessions on the efficacy of blinding procedures also remains under question. This is especially relevant in multisite projects where small unintentional variations in protocol could lead to inter-site difference. We report AE and blinding data from 1,019 participants who received up to 11 semi-consecutive sessions of active or sham transcranial alternating current stimulation (tACS), direct current stimulation (tDCS), and random noise stimulation (tRNS), at 4 sites in the UK and US. We found that AEs were often best predicted by factors other than tES, such as testing site or session number. Results from the blinding analysis suggested that blinding was less effective for tDCS and tACS than tRNS. The occurrence of AEs did not appear to be linked to tES despite the use of smaller electrodes or repeated delivery. However, blinding efficacy was impacted in tES conditions with higher cutaneous sensation, highlighting a need for alternative stimulation blinding protocols. This may be increasingly necessary in studies wishing to deliver stimulation with higher intensities.

Multi-site MRI harmonization via attention-guided deep domain adaptation for brain disorder identification.

Structural magnetic resonance imaging (MRI) has shown great clinical and practical values in computer-aided brain disorder identification. Multi-site MRI data increase sample size and statistical power, but are susceptible to inter-site heterogeneity caused by different scanners, scanning protocols, and subject cohorts. Multi-site MRI harmonization (MMH) helps alleviate the inter-site difference for subsequent analysis. Some MMH methods performed at imaging level or feature extraction level are concise but lack robustness and flexibility to some extent. Even though several machine/deep learning-based methods have been proposed for MMH, some of them require a portion of labeled data in the to-be-analyzed target domain or ignore the potential contributions of different brain regions to the identification of brain disorders. In this work, we propose an attention-guided deep domain adaptation (AD2A) framework for MMH and apply it to automated brain disorder identification with multi-site MRIs. The proposed framework does not need any category label information of target data, and can also automatically identify discriminative regions in whole-brain MR images. Specifically, the proposed AD2A is composed of three key modules: (1) an MRI feature encoding module to extract representations of input MRIs, (2) an attention discovery module to automatically locate discriminative dementia-related regions in each whole-brain MRI scan, and (3) a domain transfer module trained with adversarial learning for knowledge transfer between the source and target domains. Experiments have been performed on 2572 subjects from four benchmark datasets with T1-weighted structural MRIs, with results demonstrating the effectiveness of the proposed method in both tasks of brain disorder identification and disease progression prediction.

Lobular diameters of autopsied dog livers give clues for an appropriate liver biopsy methodology.

Hepatobiliary diseases of animals are frequently diagnosed by a combination of imaging, clinical pathology, and histopathology. A standardized surgical liver biopsy protocol, however, has not been established in veterinary medicine with regard to the selection of lobe and site of the liver to yield the most diagnostic information. To address this matter, we histologically examined 33 livers of autopsied dogs from which tissue samples of 4 different lobes as well as 4 different sites of each lobe were prepared. We measured the hepatic lobular diameter (HLD) as an objective variable to refer to the inter-lobar or inter-site difference among the biopsied samples. A measurement of 2,623 hepatic lobules resulted in 1.042 mm as the average of all the HLD values. Statistical analysis further revealed that the HLD tended to be small in a superficial 2 mm area of the liver parenchyma regardless of biopsy location, thus this area should be evaluated carefully by pathologists. The results also suggest that the HLD values of the quadrate lobe may measure smaller than those in the other lobes. Therefore, one would be able to obtain representative data of the entire liver by taking a sample from any single lobe except for the quadrate lobe. HLD measurements are needed in order to accumulate potentially useful information on the microanatomy and pathophysiology of the liver.

Effects of latitudinal transplanting on temperature sensitivity of leaf dark respiration for Larix gmelinii.

Exploring the temperature sensitivity of leaf dark respiration is of significance for understanding forest carbon cycling and its response to climate change. However, its intra-specific variability and seasonality are not clear yet. In this study, we measured the temperature sensitivity coefficient (Q10) of leaf dark respiration for Dahurian larch (Larix gmelinii) that were transplanted from four latitudinal sites (i.e., Tahe, Songling, Heihe, and Dailing) in a common garden. Our specific aims were to explore the seasonal dynamics of Q10 and compare differences in Q10 among the indivi-duals from the four latitudinal sites. The results showed that the Q10 for the four sites exhibited similar seasonal trend, with the maximum Q10 in the middle growing season. The inter-site difference in Q10 was significant, ranging from (1.48±0.01) to (2.15±0.03). Furthermore, the inter-site difference showed the same pattern across the whole growing season, i.e., the warmer and lower latitudinal sites, the higher Q10. The Q10 was significantly and positively correlated with foliar nitrogen concentration and soluble sugar concentration, and mean annual temperature and mean annual precipitation in the transplanting sites. These findings suggested that the inter-site variation in Q10 and its seasonality could be mainly attributed to the foliar nutrient concentration and adaptation of trees to the climatic conditions of the transplanting sites, which should be considered in modeling and predicting responses of forest carbon cycling to climate change.

Harmonization of pipeline for preclinical multicenter MRI biomarker discovery in a rat model of post-traumatic epileptogenesis

Preclinical imaging studies of posttraumatic epileptogenesis (PTE) have largely been proof-of-concept studies with limited animal numbers, and thus lack the statistical power for biomarker discovery. Epilepsy Bioinformatics Study for Antiepileptogenic Therapy (EpiBioS4Rx) is a pioneering multicenter trial investigating preclinical imaging biomarkers of PTE. EpiBios4Rx faced the issue of harmonizing the magnetic resonance imaging (MRI) procedures and imaging data metrics prior to its execution. We present here the harmonization process between three preclinical MRI facilities at the University of Eastern Finland (UEF), the University of Melbourne (Melbourne), and the University of California, Los Angeles (UCLA), and evaluate the uniformity of the obtained MRI data.Adult, male rats underwent a lateral fluid percussion injury (FPI) and were followed by MRI 2 days, 9 days, 1 month, and 5 months post-injury. Ex vivo scans of fixed brains were conducted 7 months post-injury as an end point follow-up. Four MRI modalities were used: T2-weighted imaging, multi-gradient-echo imaging, diffusion-weighted imaging, and magnetization transfer imaging, and acquisition parameters for each modality were tailored to account for the different field strengths (4.7 T and 7 T) and different MR hardwares used at the three participating centers.Pilot data collection resulted in comparable image quality across sites. In interim analysis (of data obtained by April 30, 2018), the within-site variation of the quantified signal properties was low, while some differences between sites remained. In T2-weighted images the signal-to-noise ratios were high at each site, being 35 at UEF, 48 at Melbourne, and 32 at UCLA (p < 0.05). The contrast-to-noise ratios were similar between the sites (9, 10, and 8, respectively). Magnetization transfer ratio maps had identical white matter/ gray matter contrast between the sites, with white matter showing 15% higher MTR than gray matter despite different absolute MTR values (MTR both in white and gray matter was 3% lower in Melbourne than at UEF, p < 0.05). Diffusion-weighting yielded different degrees of signal attenuation across sites, being 83% at UEF, 76% in Melbourne, and 80% at UCLA (p < 0.05). Fractional anisotropy values differed as well, being 0.81 at UEF, 0.73 in Melbourne, and 0.84 at UCLA (p < 0.05). The obtained values in sham animals showed low variation within each site and no change over time, suggesting high repeatability of the measurements. Quality control scans with phantoms demonstrated stable hardware performance over time. Timing of post-TBI scans was designed to target specific phases of the dynamic pathology, and the execution at different centers was highly accurate. Besides a few outliers, the 2-day scans were done within an hour from the target time point. At day 9, most animals were scanned within an hour from the target time point, and all but 2 outliers within 24 h from the target. The 1-month post-TBI scans were done within 31 ± 3 days. MRI procedures and animal physiology during scans were similar between the sites.Taken together, the 10% inter-site difference in FA and 3% difference in MTR values should be included into analysis as a covariate or balanced out in post-processing in order to detect disease-related effects on brain structure at the same scale. However, for a MRI biomarker for post-traumatic epileptogenesis to have realistic chance of being successfully translated to validation in clinical trials, it would need to be a robust TBI-induced structural change which tolerates the inter-site methodological variability described here.

Scaling effects of riparian peatlands on stable isotopes in runoff and DOC mobilisation

We combined 13months of daily isotope measurements in stream water with daily DOC and 15 min FDOM (fluorescent component of dissolved organic matter) data at three nested scales to identify how riparian peatlands generate runoff and influence DOC dynamics in streams. We investigated how runoff generation processes in a small, riparian peatland-dominated headwater catchment (0.65km2) propagate to larger scales (3.2km2 and 31km2) with decreasing percentage of riparian peatland coverage. Isotope damping was most pronounced in the 0.65km2 headwater catchment due to high water storage in the organic soils encouraging tracer mixing. At the largest scale, stream flow and water isotope dynamics showed a more flashy response. The isotopic difference between the sites was most pronounced in the summer months when stream water signatures were enriched. During the winter months, the inter-site difference reduced. The isotopes also revealed evaporative fractionation in the peatland dominated catchment, in particular during summer low flows, which implied high hydrological connectivity in the form of constant seepage from the peatlands sustaining high baseflows at the headwater scale. This connectivity resulted in high DOC concentrations at the peatland site during baseflow (∼5mgl−1). In contrast, at the larger scales, DOC was minimal during low flows (∼2mgl−1) due to increased groundwater influence and the disconnection between DOC sources and the stream. High frequency data also revealed diel variability during low flows. Insights into event dynamics through the analysis of hysteresis loops showed slight dilution on the rising limb, the strong influence of dry antecedent conditions and a quick recovery between events at the riparian peatland site. Again, these dynamics are driven by the tight coupling and high connectivity of the landscape to the stream. At larger scales, the disconnection between the landscape units increases and the variable connectivity controls runoff generation and DOC dynamics. The results presented here suggest that the processes occurring in riparian peatlands in headwater catchments are less evident at larger scales which may have implications for the larger scale impact of peatland restoration projects.

Variation in larval properties of the Atlantic brooding coral Porites astreoides between different reef sites in Bermuda

Recent research has documented phenotypic differences among larvae released from corals with a brooding reproductive mode, both among species and within broods from a single species. We studied larvae released from the common Atlantic coral Porites astreoides in Bermuda to further evaluate phenotypic variability. Inter-site differences were investigated in larvae from conspecifics at a rim and patch reef site. Larvae were collected daily for one lunar cycle from several colonies per site each year over 5 yr. Larval volume varied with reef site of origin, with colonies from the rim reef site producing larger larvae than colonies from the patch reef site. This inter-site variation in larval size could not be explained by corallite size and may be a response to different environmental conditions at the sites. Larvae from both reef sites also varied in size depending on lunar day of release over 4 yr of study. Regardless of site of origin, smaller larvae were released earlier in the lunar cycle. Over 1 yr of study, lipid and zooxanthellae content and settlement success after 48 h covaried with larval size. However, there may be a trade-off between larger larvae and reduced fecundity. Overall, larvae released from colonies from the rim reef site were larger and had greater settlement success than those from colonies from the patch reef site. This study documents larval phenotypic variability and a distinct inter-site difference in larval ecology among conspecifics within the same geographic area, which may have implications for recruitment success, population dynamics, and resilience.

Levels and distributions of organic pollutants in subtidal sediments from the Loire estuary: Are there any relationships with TTR-binding activity?

The Loire estuary runs through important urban sites with shipping, industrial and agricultural activities, being the receptacle of diffusive pollutants comprising, a mixture of contaminants such as persistent organic pollutants (POPs). This work was set out to evaluate the occurrence of thyroid endocrine disruptors in sediments of this estuary. Sediments were collected in September 2012 and April 2013, in subtidal zones along the estuary. Targeted chemical analyses of five classes of pollutants, i.e. polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs), alkylphenols (APs), and bisphenol A (BPA) were performed in sediment extracts. Extracts were further tested for their thyroid hormone (TH) disrupting potency to compete with TH for binding to its transporter protein transthyretin (TTR). The Haute-Indre site was characterized by a significant PAH contamination whereas Saint-Nazaire, Bellevue and Rezé would be particularly contaminated by PCBs. These observations could be linked to the different type of anthropogenic activities taking place close to these sites. Donges, Mindin and Paimboeuf were the sampling sites displaying the lowest contamination in PAHs, APs, PCBs and PBDEs. No inter-site difference could be observed for TTR-binding activity, which should be attributed to different compounds than the chemically analyzed compounds, as confirmed by PCA analyses. Furthermore, the TTR-binding potencies of the extracts were relatively low compared to data from literature. More investigations on the quantification of PCB and PBDE hydroxylated metabolites and other known endocrine disruptors such as pesticides or perfluorinated compounds could be considered, as well as bioassays highlighting other endocrine disrupting effects.

Light Use Efficiency over Two Temperate Steppes in Inner Mongolia, China

Vegetation light use efficiency (LUE) is a key parameter of Production Efficiency Models (PEMs) for simulating gross primary production (GPP) of vegetation, from regional to global scales. Previous studies suggest that grasslands have the largest inter-site variation of LUE and controlling factors of grassland LUE differ from those of other biomes, since grasslands are usually water-limited ecosystems. Combining eddy covariance flux data with the fraction of photosynthetically active radiation absorbed by the plant canopy from MODIS, we report LUE on a typical steppe and a desert steppe in Inner Mongolia, northern China. Results show that both annual average LUE and maximum LUE were higher on the desert steppe (0.51 and 1.13 g C MJ−1) than on the typical steppe (0.34 and 0.88 g C MJ−1), despite the higher GPP of the latter. Water availability was the primary limiting factor of LUE at both sites. Evaporative fraction (EF) or the ratio of actual evapotranspiration to potential evapotranspiration (AET/PET) can explain 50–70% of seasonal LUE variations at both sites. However, the slope of linear regression between LUE and EF (or AET/PET) differed significantly between the two sites. LUE increased with the diffuse radiation ratio on the typical steppe; however, such a trend was not found for the desert steppe. Our results suggest that a biome-dependent LUEmax is inappropriate, because of the large inter-site difference of LUEmax within the biome. EF could be a promising down-regulator on grassland LUE for PEMs, but there may be a site-specific relationship between LUE and EF.

Symbiotic and phenotypic characterization of Rhizobium isolates of field pea (Pisum sativum L.) Fabaceae, from central and southern Ethiopia

A total of 25 rhizobial isolates from field pea ( Pisum sativum L .) were collected from Shewa, Gojam, Gondar, Wollo and Tigray, and authenticated as root nodule using the trap host. They showed significant variations in their symbiotic effectiveness in nitrogen fixation and enhancing growth of the pea cultivar Markose plants compared to the uninoculated and non-fertilized control plants on sand culture under greenhouse conditions. Although there was inter-site difference in harbouring effective and very effective isolates ranging from 86% (Tigray) and 67% (Gondar) in terms of shoot dry matter accumulation of 50-100%, on the average 76% of the pea rhizobial isolates in the soils of major growing areas in the country were effective and very effective. The inoculated plants also showed differences in total nitrogen contents in the range of 1.72% and 2.93%. These isolates were then characterized based on their cultural, physiological and ecological features in relation to their symbiotic characteristics. The isolates showed diversity in their eco-physiological tolerance (NaCl, pH and temperature) inherent resistance to antibiotics and heavy metals, and heterotrophic competence of utilization of 17 carbon sources. Consequently, isolates NSRlFP1, NSRlFP3, NSRlFP13, NSRlFP17 and NSRlFP18 were the elite rhizobia that can be selected and further tested for their genetic and symbiotic performance in field trials for future bio-inoculant formulation. Key words/phrases: Antibiotic resistance, Eco-physiological tolerance, Heavy metal resistance, Symbiotic effectiveness.

Factors affecting 210Po and 210Pb activity concentrations in mussels and implications for environmental bio-monitoring programmes

The activity of 210Po and 210Pb was determined in mussels of the same size (3.5–4.0 cm shell length) sampled monthly over a 17-month period at the Atlantic coast of Portugal. Average radionuclide concentration values in mussels were 759 ± 277 Bq kg −1 for 210Po (range 460–1470 Bq kg −1 dry weight), and 45 ± 19 Bq kg −1 for 210Pb (range 23–96 Bq kg −1 dry weight). Environmental parameters and mussel biometric parameters were monitored during the same period. Although there was no seasonal variation of radionuclide concentrations in sea water during the study period, the concentration of radionuclide activity in mussels varied seasonally displaying peaks of high concentrations in winter and low concentrations in summer. Analysis of radionuclide data in relation to the physiological Condition Index of mussels revealed that 210Po and 210Pb activities in the mussel (average activity per individual) remained nearly constant during the investigation period, while mussel body weight fluctuated due to fat storage/expenditure in the soft tissues. Similar variation of radionuclide concentrations was observed in mussels transplanted from the sea coast into the Tejo Estuary. However, under estuarine environmental conditions and with higher food availability throughout the year, transplanted mussel Condition Index was higher than in coastal mussels and average radionuclide concentrations were 210 ± 75 Bq kg −1 (dry weight) for 210Po and 10 ± 4 Bq kg −1 (dry weight) for 210Pb, therefore lower than in coastal mussels with similar shell length. It is concluded that the apparent seasonal fluctuation and inter-site difference of radionuclide concentrations were mostly caused by mussel body weight fluctuation and not by radionuclide body burden fluctuation. This interpretation can be extended to the apparent seasonal fluctuation in concentrations of lipophilic and lipophobic contaminants in mussels, and provides an explanation for occasional high concentrations of 210Po and man-made contaminants measured in mussels far from pollution sources.

Factors Influencing Interannual and Intersite Variability in the Diet of Trachypithecus francoisi

Comparative studies of the diet of the same species in different habitats, and over the long term, are essential to understanding a species’ behavioral and ecological plasticity. Moreover, such studies can help researchers and managers evaluate a species’ capacity to cope with changes in habitat quality resulting from natural processes or human disturbance, which is important for developing conservation strategies. We compared dietary data for Francois’ langur (Trachypithecus francoisi) collected at Nonggang and Fusui Nature Reserves, Guangxi Province, China, over 2 separate study periods to evaluate interannual and intersite variation in diet. Young leaves were the preferred staple foods for langurs, whereas mature leaves and seeds served as fallback foods in response to seasonal shortage in the abundance of young leaves. Species composition of the diets and the percentage of feeding records for plant species varied between the 2 study periods. The langurs at both study sites fed selectively, and they did not base their diet simply on the abundance of plant species in the habitat. However, the plant species eaten by langur groups inhabiting the 2 different reserves were markedly different, and the top 10 food species eaten by the Fusui group showed no overlap with those eaten by the Nonggang group. The variation may be related to differences in forest composition resulting from different level of human disturbance. In summary, our results indicate that Francois’ langurs exhibit a comparable dietary pattern both temporally and geographically, but there is marked interannual and intersite difference in species composition of the langur diet.

Inter-site differences in the biodynamics and body concentration of silver in a marine predatory gastropod

The body concentrations of Ag in a top marine predator, the whelk Thais clavigera, varied significantly (1.10 to 4.67 µg g -1 dry wt) in individuals collected from 3 intertidal rocky shores in Hong Kong, whereas there was no significant difference in Ag concentrations in species from lower trophic levels (macroalgae Ulva sp. and rocky oyster Saccostrea cucullata). We compared the variation in Ag biodynamics in whelks collected from these 3 locations. There was no significant difference in the Ag dietary assimilation efficiency, Ag dissolved uptake rate, or estimated metallothionein concen- tration among the 3 locations. Significant differences were found in the Ag efflux rate constant and the subcellular distribution of Ag. Whelks from Clear Water Bay, which had the lowest body concentration of Ag, had a higher Ag efflux rate constant (0.0268 d -1 ) than those collected from the other 2 sites (0.0076 to 0.0095 d -1 ), as well as a correspondingly lower fraction of Ag in the metallothionein-like pro- tein pool (which might contain both metallothioneins and other low molecular weight thiols). The Ag distribution in the other 4 subcellular fractions (metal-rich granules, cellular debris, organelles, heat- sensitive proteins) was similar among the 3 sites. The biokinetic model demonstrated that biokinetic parameters can predict this 4-fold inter-site difference of body Ag concentrations in whelks. Moreover, such variation was mainly caused by variation in Ag efflux, although other parameters such as dietary assimilation and the concentration of Ag in prey were also important. Our calculations suggest that the prey composition may be specific to the site. The complexity of food webs should thus be considered when examining metal bioaccumulation in marine predators.

Spatial Distribution of Polychlorinated Biphenyls in Coastal Marine Sediments Receiving Industrial Effluents in Kuwait

The concentrations of polychlorinated biphenyls (PCBs) were measured in surficial sediments receiving industrial and municipal effluents in Kuwait. The SigmaPCB concentrations varied by two orders of magnitude ranging from 0.4 to 84 microg kg(-1) dw. The homologue distribution in the study favored the more chlorinated congeners and generally followed the order: penta-PCBs > hexa-PCBs > tetra-PCBs approximately hepta-PCBs, with the dominant congeners being 138, 101, 110, 180, 153, 132, 149, and 118. The spatial distribution revealed significant intersite difference in concentration, with high levels encountered close to a harbor and several wastewater outlets suggesting that point source input is the primary delivery mechanism of PCBs to the sediment. This study suggests that atmospheric deposition of PCBs may not be a significant delivery mechanism to sediments in Kuwait possibly due to low annual precipitation and high annual temperatures that are experienced in the Arabian Gulf. The implication of this observation is that PCBs in air are likely to remain in the gas phase long enough to be subject to long-range atmospheric transport to other regions.

Unintended pregnancy risk in an emergency department population

Objective To assess unintended pregnancy risk and associated factors among female urban Baltimore emergency department (ED) attendees. Methods A cross-sectional anonymous questionnaire study was completed by 790 women, sufficient to detect a 5% difference of unintended pregnancy risk in the national population and a 10% intersite difference with 80% power. The results were analyzed with chi-square tests, univariate and multivariate logistic regression analyses. Results Female ED attendees are at greater risk for unintended pregnancy (33.5%), particularly those of lower income (p=.006) and without a primary care provider (p=.003). Unintended pregnancy risk did not vary between sites by any variable except young age despite the fact that sites varied significantly by race, insurance and income measures. Conclusion Women using the ED are at increased risk for unintended pregnancy and are less likely to have access to a regular medical care source; thus, the ED represents a possible contraceptive provision site.

Primary care services for an emergency department population: a novel location for contraception

Objective To assess contraceptive provision site preferences in female urban Baltimore emergency department patients. Methods This cross-sectional questionnaire study was completed by 790 women, a population sufficient to detect a 10% intersite difference. The results were analyzed with chi-square, univariate and multivariate logistic regression analyses. Results Obtaining contraception other than from a physician's office was acceptable to 57.2% of the subjects, particularly those uninsured (p=.006) and without primary care providers (p<.001). Contraceptive provision in the emergency department (ED) was acceptable to 44.0%, particularly those who are frequent ED users (p=.003) and those at risk for unintended pregnancy (p=.024; pooled, p<.001). Care in nontraditional settings may preclude pelvic examination; 34.0% of the subjects felt safe obtaining contraception without this examination, significantly for those desiring contraceptive provision in the ED. Conclusion Contraceptive services are acceptable in nontraditional settings, including the ED, particularly to women of limited resources. This service is acceptable without pelvic examination for a sizable proportion of the women using the ED.

Mapping, profiling and clustering of pressure pain threshold (PPT) in edentulous oral mucosa

Edentulous oral mucosa involves different tissue types, various innervation and wound healing process. We hypothesized that pressure pain threshold (PPT) of edentulous oral mucosa varies significantly among different regions. The objective of this study is to examine regional differences and correlations of PPT in edentulous oral mucosa. Pain threshold (PPT) was measured at 112 sites in 15 edentulous patients using an electric-controlled pressure algometer. PPT mapping was created by the level of PPT, and PPT clustering was undertaken based on the inter-site correlation of PPT. PPT increased from the anterior to posterior alveolus in both maxilla and mandible, but decreased from the anterior palate to the posterior palate. PPT decreased from the ridge crest to the buccal vestibule. The inter-site difference was four fold within the maxilla and 2.4 fold within the mandible. Principal component analysis applied on PPT inter-site correlation matrix revealed that the maxilla and mandible could be differentiated statistically. The maxilla and mandible were divided into three and four clusters, respectively. These results demonstrate that different areas of edentulous oral mucosa have different PPT and that the PPT varies proportionally in selected areas, providing useful diagnostic and therapeutic information in removable prosthodontics and a new opportunity for understanding pain underneath the denture.

Characterisation and source attribution of the semi-volatile organic content of atmospheric particles and associated vapour phase in Birmingham, UK

Abstract Concentrations of n -alkanes, petroleum biomarkers such as hopanes and steranes, n -alkanoic acids, n -alkanols, polycyclic aromatic hydrocarbons (PAH), dicarboxylic acids, and selected oxygenated PAH were separately determined in total suspended particulate matter and associated vapour phase in ambient air in Birmingham, UK. Samples were taken simultaneously at two locations on 24 separate occasions every 1–2 weeks between August 1999 and August 2000. Site A was 10 m from a busy road, 800 m from site B that was located within the “green space” of the University of Birmingham campus. Despite some differences in concentrations of some compounds, data from this study is in line with that reported in London, UK and in California. Differences between Sites A and B in both concentrations and carbon preference indices are consistent with greater traffic inputs at Site A , with some evidence of an appreciable biogenic input of n -alkanols and n -alkanes at the less-traffic influenced and more vegetated Site B . The biogenic input at Site B appears greater in the spring and summer months and suggests that biogenic emissions are appreciable even in British urban areas. Secondary formation mechanisms for some compounds including dicarboxylic acids and oxygenated PAH like fluoren-9-one are indicated by the lack of any significant intersite difference in concentrations. Intersite differences in concentrations provide new evidence that while petroleum biomarkers arise predominantly from local traffic, regional as well as local sources play an important role for the higher molecular weight PAH which exist predominantly in the particle phase.

Ammonium in coastal Antarctic aerosol and snow: Role of polar ocean and penguin emissions

Year‐round aerosol samples collected in the boundary layer at coastal Antarctic sites (Dumont D'Urville, Neumayer, and Halley) indicate a seasonal cycle of ammonium concentrations with a minimum in winter (April–September). A large intersite difference appears in the summer (November–February) maxima values, from ∼12.5 ng m−3 at Neumayer to 140–230 ng m−3 at Dumont D'Urville. At Dumont D'Urville, ammonium concentrations are the largest ever reported from Antarctic sites, and the large summer maxima are associated with large enrichments with respect to sea salt for potassium and calcium. In addition, seasonal ammonium variations at Dumont D'Urville are in phase with a well‐marked seasonal cycle of oxalate concentrations which exhibit maxima of 5–10 ng m−3 in spring and summer and minima of less than 0.5 ng m−3 in winter. Such a composition of aerosols present in the boundary layer at Dumont D'Urville in summer is linked to the presence of a large Adélie penguin population from the end of October to March at the site. Ornithogenic soils (defined as guano‐enriched soils), together with the bacterial decomposition of uric acid, are a source of ammonium, oxalate, and cation (such as potassium and calcium) aerosol, in addition to a subsequent large ammonia loss from ornithogenic soils to the atmosphere. The total breeding population of 5 million Adélie penguins widely distributed around the Antarctic continent may emit, at most, some 2.5 × 10−4 Mt of NH3‐N during the summer months. In contrast, Halley and Neumayer Stations are far less exposed to penguin colony emissions. At Neumayer, ammonium concentrations peak from January to March and are in phase with the increase of biogenic sulfur species. Here the NH4+/(MSA + nss SO4−) molar ratio is close to 13% in summer aerosol and to 40% in winter aerosol. Using this summer ratio, which may be related to ammonia and sulfur oceanic emissions occurring south of 50°S in summer and estimated DMS emissions in these regions at this time, we derive an upper limit of 0.064 Mt NH3‐N emitted per year by the high‐latitude Southern Ocean in summer. This study indicates a very limited ammonia neutralization of acidic sulfate aerosols at high southern latitudes, except in the vicinity of ornithogenic soils occupied by large penguin colonies.