bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simultaneous Assessment of Myocardial Perfusion, Wall Motion, and Deformation during Myocardial Contrast Echocardiography: A Feasibility Study
Authors: Zoppellaro Giacomo , Venneri Lucia , Khattar Rajdeep S. , Li Wei , Senior Roxy 
Published: February 2016

AimsUltrasound contrast agents may be used for the assessment of regional wall motion and myocardial perfusion, but are generally considered not suitable for deformation analysis. The aim of our study was to assess the feasibility of deformation imaging on contrast‐enhanced images using a novel methodology.Methods and ResultsWe prospectively enrolled 40 patients who underwent stress echocardiography with continuous intravenous infusion of SonoVue for the assessment of myocardial perfusion imaging with flash replenishment technique. We compared longitudinal strain (Lε) values, assessed with a vendor‐independent software (2D CPA), on 68 resting contrast‐enhanced and 68 resting noncontrast recordings. Strain analysis on contrast recordings was evaluated in the first cardiac cycles after the flash. Tracking of contrast images was deemed feasible in all subjects and in all views. Contrast administration improved image quality and increased the number of segments used for deformation analysis. Lε of noncontrast and contrast‐enhanced images were statistically different (−18.8 ± 4.5% and −22.8 ± 5.4%, respectively; P < 0.001), but their correlation was good (ICC 0.65, 95%CI 0.42–0.78). Patients with resting wall‐motion abnormalities showed lower Lε values on contrast recordings (−18.6 ± 6.0% vs. −24.2 ± 5.5%, respectively; P < 0.01). Intra‐operator and inter‐operator reproducibility was good for both noncontrast and contrast images with no statistical differences.ConclusionsOur study shows that deformation analysis on postflash contrast‐enhanced images is feasible and reproducible. Therefore, it would be possible to perform a simultaneous evaluation of wall‐motion abnormalities, volumes, ejection fraction, perfusion defects, and cardiac deformation on the same contrast recording.
Intraventricular Isovolumic Relaxation Flow Patterns Studied by Using Vector Flow Mapping
Authors: Zhang Haibin , Ren Xiaofeng , Song Jin , Cao Xinyu , Wang Benna , Liu Ying , Li Zhiguo , Ma Na 
Published: February 2016

AimsThe purpose of this study was to characterize isovolumic relaxation flow (IRF) in the left ventricle (LV) in patients with a wide spectrum of LV dysfunction.MethodsColor Doppler flow imaging was performed in 61 patients with coronary artery disease, 29 patients with dilated cardiomyopathy, and 41 healthy controls. Vector flow mapping was used to analyze the Doppler data.ResultsIRF patterns were divided into three types: pattern A, an apically directed flow; pattern B, a bidirectional flow with small scattered vortices; and pattern C, a large vortex persisting throughout the entire isovolumic relaxation (IVR) period. All controls demonstrated an IRF corresponding to pattern A. Of the 90 patients, 42 demonstrated IRF as pattern A, 26 as pattern B, and 22 as pattern C. There were significant differences among the subgroups of patients with different IRF patterns and the control group in LV‐ejection fraction, size, wall‐motion score index, apical wall‐motion score index, systolic and diastolic mitral annular velocities, ratio of the mitral inflow E velocity to early diastolic mitral annular velocity (E/e′), and left atrial diameter (all P < 0.05). In the patient group, a higher wall‐motion score index independently predicted the IRF pattern. In patients with severe LV dysfunction, a higher E/e′ ratio was the independent predictor of the persistence of a large vortex during the IVR period.ConclusionsThe IRF pattern is associated with LV function. A large intraventricular vortex persisting during the IVR period should be indicative of increasingly depressed LV function.
Portosystemic shunts: A diagnostic challenge
Authors: Gold J. R. 
Published: February 2016

SummaryThe case report in this issue by Woodfordet al. (2017) describes the surgical management of an extrahepatic portosystemic shunt in a 5‐week old miniature foal. Only a handful of reports exist in the literature describing surgical procedures for repair of these congenital abnormalities in foals. One of the important aspects of the accompanying case report was the multidisciplinary approach taken in handling, imaging and surgical repair of the extrahepatic shunt. Small animal internal medicine specialists and surgeons diagnose portosystemic shunts much more frequently than equine veterinarians, regardless of whether they are general practitioners or specialists. It is therefore important to work as a team with small and large animal practitioners. The case described by Woodfordet al. (2017) had a positive outcome.
Temperature‐dependent uniaxial ratchetting of ultra‐high molecular weight polyethylene
Authors: Chen K. , Kang G. , Lu F. , Xu J. , Jiang H. 
Published: January 2016

AbstractUniaxial stress‐controlled cyclic tests were performed on the ultra‐high molecular weight polyethylene (UHMWPE) polymer at different temperatures. The effects of stress level, stress rate, peak/valley stress hold and loading history on the ratchetting of the UHMWPE were discussed at different temperatures, and the temperature‐dependence of ratchetting was addressed. It is concluded from the experimental observations that the ratchetting of the UHMWPE depends greatly on the test temperature, and the ratchetting strain increases with the increasing temperature from −20 to 37 °C, but decreases when the temperature is equal to or higher than 60 °C in some cases. The ratchetting is also time‐dependent and increases with the increase of peak stress hold time and the decrease of stress rate. The ratchetting presents apparent loading history dependence, and previous cyclic history with higher stress level remarkably restrains the occurrence of ratchetting in the subsequent cyclic loading cases with lower stress levels, but previous cyclic history with lower stress level hardly influences the ratchetting in the subsequent cyclic loading cases with higher stress levels.
A landscape approach to advance intermittent river ecology
Authors: Datry Thibault , Pella Herve , Leigh Catherine , Bonada Núria , Hugueny Bernard 
Published: February 2016

Summary

Intermittent rivers are increasingly viewed as shifting mosaics of lotic (flowing water), lentic (standing water) and terrestrial (dry riverbed) habitats. The diversity, spatial arrangement, temporal turnover and connectivity of these habitats are controlled by the magnitude, frequency, duration and extent of drying and rewetting events, which maintain habitat heterogeneity and control biodiversity and biogeochemical processes in intermittent rivers.

We consider intermittent rivers as spatiotemporal landscape mosaics to identify the implications such a view has for empirical and theoretical developments in landscape and river ecology. Using observational data of flow states collected by citizen scientists along 1400 km of river channels in western France, we used landscape metrics and ecologically scaled indices for four hypothetical, aquatic species (two fish and two insects) to describe the dynamics of intermittent river mosaics for five catchments.

Dry patches dominated most observation dates but flowing patches had the longest average length and occupied the greatest proportion of channel length. At the start of each summer, catchments were almost entirely composed of flowing patches but lentic and dry patches could represented up to 80% of the catchments as summer progressed. Patch dynamics were typified by high levels of spatiotemporal variability. In contrast, ecologically scaled indices did not vary greatly among catchments within species. The ecologically scaled indices representing small fish were the most affected by habitat fragmentation.

Such a landscape perspective could affect understanding of biodiversity patterns and biogeochemical processes in intermittent rivers. We outline the methodological developments required to integrate landscape approaches into intermittent river research, the associated challenges and current limitations in landscape ecology tools and models and the benefits of citizen science data sets. The continued quantification of shifting habitat mosaics in intermittent rivers will provide multiple opportunities to advance river and landscape ecology.
Lake‐type‐specific seasonal patterns of nutrient limitation in German lakes, with target nitrogen and phosphorus concentrations for good ecological status
Authors: Dolman Andrew M. , Mischke Ute , Wiedner Claudia 
Published: February 2016

Summary

Eutrophication is a global environmental problem that leaves many lakes with impaired ecological status. Human activity has increased the total concentrations of both nitrogen and phosphorus in aquatic systems, but their relative influence on phytoplankton biomass is uncertain. Their action as alternative limiting resources complicates assessment of their relative influence and disagreement may be in part due to seasonal shifts and lake‐type‐specific differences in the prevalence of limitation by nitrogen versus phosphorus. Debate continues as to whether measures to reduce nitrogen would be beneficial in addition to controls placed on phosphorus.

We used a piecewise model to test whether total nitrogen (TN) concentrations, in addition to total phosphorus (TP), influence phytoplankton biomass in 369 lowland German lakes. The piecewise model predicts biomass from TN for low N : P ratio lakes, and from TP for high N : P ratio lakes. We tested three N : P mass ratios to divide lakes: dissolved inorganic nitrogen to TP (DIN : TP), DIN to dissolved reactive phosphorus (DIN : DIP) and TN : TP. TN was a better predictor of biomass than TP when either the DIN : TP ratio was below 1.6, DIN : DIP was below 8.4, or TN : TP below 29; predictions were most accurate when using the DIN : TP ratio.

To investigate seasonal and lake‐type‐specific patterns of N and P limitation, we used the DIN : TP ratio, together with absolute concentrations of DIN and DIP, to predict the limiting nutrient at each lake in each month of the vegetation period. N limitation was much more common in polymictic than stratified lakes. While a high proportion of both stratified and polymictic lakes were P limited in early spring (60–70%), for polymictic lakes, we found a strong shift from P limitation to N limitation in summer: more than 50% of polymictic lakes were N limited between June and September and only 15–30% were P limited.

To obtain lake‐type‐specific nutrient targets we estimated the average TN and TP concentrations at which lakes of different types achieved good ecological status according to EU water framework directive criteria. Stratified lakes achieved good ecological status at concentrations of 400–500 μg L−1 TN or 20–35 μg L−1 TP, while for polymictic lakes values of 500–1000 μg L−1 TN, or 35–75 μg L−1 TP were required.

We estimate that nitrogen has an important influence on phytoplankton biovolume, and thus ecological status, for many polymictic lakes in Germany. While there is some uncertainty in the nutrient targets required to achieve good ecological status, this uncertainty is small compared with the range of concentrations currently observed, and lakes with moderate or worse status have concentrations of both TN and TP that are far above these current target estimates.
Beaver activity increases aquatic subsidies to terrestrial consumers
Authors: McCaffery Magnus , Eby Lisa 
Published: February 2016

Summary

The occurrence and importance of fluxes of nutrients and organic matter between aquatic and terrestrial habitats is well established, but how catchment characteristics influence these fluxes remains unclear. Beaver (Castor canadensis) alter freshwater ecosystems and increase aquatic production, but it is unknown how these changes influence the magnitude and lateral dispersal of aquatic nutrients into terrestrial ecosystems.

We examined differences in abundances of dominant aquatic invertebrates, wolf spiders (Lycosidae), and deer mice (Peromyscus maniculatus), at beaver and non‐beaver sites. We used stable isotopes to track aquatic‐derived carbon in terrestrial consumers and linear mixed‐effects models to examine the importance of beaver presence and distance from stream channel on the percentage of aquatic‐derived carbon in terrestrial consumers.

Sites with beaver activity had >200% higher aquatic invertebrate emergence rates as well as 60% and 75% higher abundances of spiders and deer mice, respectively, relative to non‐beaver sites.

The tissues of both spiders and deer mice exhibited a greater percentage of aquatic‐derived carbon at sites with beaver activity than at non‐beaver sites.

Aquatic‐derived carbon in deer mice declined linearly with distance from the stream edge at both beaver and non‐beaver sites. The contribution of aquatic‐derived carbon in mice extended farther from the stream edge in beaver‐modified catchments. Aquatic‐derived carbon in spiders also declined linearly with distance from the stream at beaver sites but not at non‐beaver sites.

We documented a novel example of increased aquatic subsidy to riparian areas with beaver activity, leading to changes in the magnitude of the lateral dispersal of aquatic nutrient subsidies to the terrestrial environment in small stream systems. Understanding the effects of natural disturbance regimes, such as beaver modification, will be important for management and, where appropriate, restoration of natural catchment processes.
Dual, differential isotope labeling shows the preferential movement of labile plant constituents into mineral‐bonded soil organic matter
Authors: Haddix Michelle L. , Paul Eldor A. , Cotrufo M. Francesca 
Published: February 2016

AbstractThe formation and stabilization of soil organic matter (SOM) are major concerns in the context of global change for carbon sequestration and soil health. It is presently believed that lignin is not selectively preserved in soil and that chemically labile compounds bonding to minerals comprise a large fraction of the SOM. Labile plant inputs have been suggested to be the main precursor of the mineral‐bonded SOM. Litter decomposition and SOM formation are expected to have temperature sensitivity varying with the lability of plant inputs. We tested this framework using dual 13C and 15N differentially labeled plant material to distinguish the metabolic and structural components within a single plant material. Big Bluestem (Andropogon gerardii) seedlings were grown in an enriched 13C and 15N environment and then prior to harvest, removed from the enriched environment and allowed to incorporate natural abundance 13C–CO2 and 15N fertilizer into the metabolic plant components. This enabled us to achieve a greater than one atom % difference in 13C between the metabolic and structural components within the plant litter. This differentially labeled litter was incubated in soil at 15 and 35 °C, for 386 days with CO2 measured throughout the incubation. After 14, 28, 147, and 386 days of incubation, the soil was subsequently fractionated. There was no difference in temperature sensitivity of the metabolic and structural components with regard to how much was respired or in the amount of litter biomass stabilized. Only the metabolic litter component was found in the sand, silt, or clay fraction while the structural component was exclusively found in the light fraction. These results support the stabilization framework that labile plant components are the main precursor of mineral‐associated organic matter.
Can the richness–climate relationship be explained by systematic variations in how individual species’ ranges relate to climate?
Authors: Boucher‐Lalonde Véronique , Morin Antoine , Currie David J. 
Published: January 2016

AbstractAimAt large spatial extents, the species richness of high‐level taxa is generally strongly positively correlated with temperature and precipitation, and consistently so across space and time. Here, we test whether this richness–climate relationship is driven by systematic associations between climate and characteristics of the geographical ranges of individual species. Specifically, we test the hypotheses that spatial variations in richness are driven by variations in species mean range size, climatic niche‐breadth, climatic range filling, frequency distribution of climatic niche position and/or frequency distribution of extant climatic conditions.LocationThe Americas.MethodsWe tested hypothetical effects of climatically constrained ranges on species richness using the breeding ranges of 3277 birds and 1659 mammals. We tallied species richness in 104‐km2 quadrats in the Americas as well as summary statistics describing the geographical ranges and climatic niches of the species occurring in each quadrat. We then used regression models to relate species richness to those characteristics.ResultsWe found that species mean range size, climatic niche‐breadth and range filling were generally, but inconsistently, negatively related to species richness. As predicted, species richness per quadrat increased with the number of species having their climatic niches centred in the climatic conditions of the quadrats and with the geographical extent of those conditions, although these relationships were relatively weak.Main conclusionThe richness–climate relationship appears to be largely decoupled from systematic variations in the characteristics of species climatic niches. Species generally have larger geographical ranges, wider climatic niches and higher range filling in species‐poor areas, each of which, all else being equal, should generate a richness–climate relationship the inverse of what we generally observe in nature. More species have their ranges centred on warm, wet and common climatic conditions. However, temperature and precipitation variables themselves explain more of the variance in species richness than the measured characteristics of species climatic niches.
Beneficial effects of dietary docosahexaenoic acid intervention on cognitive function and mental health of the oldest elderly in Japanese care facilities and nursing homes
Authors: Hashimoto Michio , Kato Setsushi , Tanabe Yoko , Katakura Masanori , Mamun Abdullah Al , Ohno Miho , Hossain Shahdat , Onoda Keiichi , Yamaguchi Shuhei , Shido Osamu 
Published: January 2016

AimWe examined the effects of the administration of docosahexaenoic acid (DHA)‐enriched meals on cognitive function in the oldest elderly with cognitive impairment, such as dementia, living in nursing homes, and on the improvement in caregiver burden at aging agencies.MethodsParticipants in elderly care facilities and nursing homes (n = 75; 88.5 ± 0.6 years) were randomized in active and placebo groups. The active group had family‐style meals containing an additional 1720 mg of docosahexaenoic acid per day for 12 months. At baseline, and after 6 and 12 months of intervention, cognitive function was assessed using Hasegawa's Dementia Scale‐Revised and the Mini‐Mental State Examination; mental health condition was assessed with the Apathy scale and the Zung Self‐Rating Depression Scale; caregiver burden was evaluated using Zarit Burden Interview scores; and participants’ serum biochemical factors were measured.ResultsThe participants were suggested to have dementia. After 12 months, the mean change in Mini‐Mental State Examination subitem “Registration” score from baseline to month 12 showed a tendency to be greater in the active group than that in the placebo group. Mean changes in the Apathy scale from baseline to month 12 were less, and the changes in the Zung Self‐Rating Depression Scale and the total Zarit Burden Interview scores showed a tendency to be lower in the active group than in the placebo group, respectively.ConclusionThese results suggest that docosahexaenoic acid‐enriched meals protect against age‐related cognitive decline, and also improve apathy and caregiver burden for the oldest‐elderly Japanese with cognitive impairment, such as dementia. Geriatr Gerontol Int 2017; 17: 330–337.
Direct and Indirect Costs of Chronic and Episodic Migraine in the United States: A Web‐Based Survey
Authors: Messali Andrew , Sanderson Joanna C. , Blumenfeld Andrew M. , Goadsby Peter J. , Buse Dawn C. , Varon Sepideh F. , Stokes Michael , Lipton Richard B. 
Published: February 2016

ObjectiveThe objective of this study was to compare the societal direct and indirect costs of chronic and episodic migraine in the United States.BackgroundEpisodic and chronic migraine are distinguished by the frequency of headache‐days. Chronic migraine has a greater overall impact on quality of life than does episodic migraine. Individuals with chronic migraine also use more healthcare resources (resulting in higher direct costs) and experience greater decreases in productivity (resulting in higher indirect costs) than those with episodic migraine as shown in the American Migraine Prevalence and Prevention (AMPP) Study.MethodsThe International Burden of Migraine Study utilized a web‐based questionnaire to elicit data on several topics related to the burden of migraine illness, including health resource utilization and productivity losses. Potential survey participants were identified by Synovate Healthcare (Chicago, IL, USA) from a pool of registered panelists from various countries. The panelists were screened online to determine eligibility and to identify individuals with migraine (episodic or chronic), based on reported symptoms. Participants from the United States were divided into episodic and chronic migraine groups, based on reported headache‐day per month frequency. Direct and indirect costs were estimated by applying estimated unit costs to reported headache‐related productivity losses and resource use. Costs were compared between participants with episodic and chronic migraine.ResultsMean [standard deviation] total annual cost of headache among people with chronic migraine ($8243 [$10,646]) was over three times that of episodic migraine ($2649 [$4634], P < .001). Participants with chronic migraine had significantly greater direct medical costs ($4943 [$6382]) and indirect (lost productivity) costs ($3300 [$6907]) than did participants with episodic migraine (direct, $1705 [$3591]; indirect, $943 [$2084]) (P < .001 for each). Unlike previous findings, direct medical costs constituted the majority of total headache‐related costs for both chronic migraine (60.0%, $4943 of $8243) and episodic migraine (64.3%, $1705 of $2649) participants. A large portion of direct medical costs are attributable to pharmaceutical utilization among both chronic migraine (80%, $3925 of 4943) and episodic migraine (70%, $1196 of $1705) participants.ConclusionThe results of this study build on previous results of the AMPP Study, demonstrating that headache‐related direct, indirect, and total costs are significantly greater among individuals with chronic migraine than with episodic migraine in the United States.