bluuebunny/crossref_metadata_2025_split huggingface dataset:
Concussion Management, Education, and Return-to-Play Policies in High Schools
Authors: Esquivel Amanda , Haque Sadiq , Keating Patrick , Marsh Stephanie , Lemos Stephen 
Published: February 2013

Background: Concussions represent 8.9% to 13.2% of all high school athletic injuries. How these injuries are managed is currently unknown. Hypothesis: There are differences in concussion management and awareness among boys football, boys ice hockey, and boys and girls soccer. Study Design: Descriptive epidemiologic study. Methods: High school athletic directors were contacted via e-mail and asked to complete, and request that their staff complete, an online survey with 4 sections aimed at athletic directors, head coaches, team physicians, and certified athletic trainers. Results: According to coaches, concussion awareness education was provided for football (97%), hockey (65%), and boys and girls soccer (57% and 47%, respectively) ( P < 0.01). Use of sideline screening tools was significantly greater for football ( P = 0.03). All participants agreed that a player who has suffered a concussion cannot return to play the same day. Conclusion: There is a difference in concussion management and awareness among the 4 sports. Concussion education is well promoted in football but should be expanded in soccer and hockey. Players are not allowed to return to play the same day, and the majority are referred to a physician. Clinical Relevance: Study results highlight the differences in concussion education among sports. Health care providers should address these gaps.
Blacks and whites in Cuba have equal prevalence of hypertension: confirmation from a new population survey
Authors: Ordúñez Pedro , Kaufman Jay S , Benet Mikhail , Morejon Alain , Silva Luis C , Shoham David A , Cooper Richard S 
Published: February 2013

Abstract

Background
The excess burden of hypertension among blacks has been a prominent feature of the heath disparities literature, and many scientists presume it to be a stable and inevitable phenomenon. The underlying causes of this disparity can only be disentangled in a setting in which the population does not experience racial stratification of socioeconomic opportunities. While such conditions of racial equality remain uncommon, they may be approximated in Cuba, a country with a persistent policy of social inclusion over the last 5 decades.

Methods
We report on a 2010–2011 stratified probability sample of those aged 15–74 years from the urban population of Cienfuegos in central Cuba. A total of 1496 adults (880 women and 616 men) were recruited and assessed for blood pressure and anthropometrics according to standardized protocols, as well as medication use, educational attainment and observed skin tone (dichotomized into “black” and “white”). Weighted tabular and regression analyses were conducted to estimate adjusted prevalences of hypertension (> 140/90 mmHg) and adjusted prevalence odds ratios for contrasts between the two skin color groups.

Results
Mean pressures were higher for men than for women, but overall did not differ importantly between racial groups. About half of all diagnosed hypertensive men were on medication, a proportion that did not vary by racial group. For women, however, adjusted prevalence was somewhat higher among blacks, and treatment and control rates were also somewhat advantaged for white women.

Conclusions
Overall, skin color was unrelated to mean blood pressure or hypertensive status in this population, although among women specifically some racial advantage appears evident in adjusted prevalence and control, and should be investigated further. The overall null result suggests that Cuba may exemplify the social conditions in which racial excess in hypertension, characteristic of much of the western world, is not a necessary reality.
Gastrointestinal function development and microbiota
Authors: Di Mauro Antonio , Neu Josef , Riezzo Giuseppe , Raimondi Francesco , Martinelli Domenico , Francavilla Ruggiero , Indrio Flavia 
Published: February 2013

Abstract
The intestinal microbiota plays an important role in the development of post-natal gastrointestinal functions of the host. Recent advances in our capability to identify microbes and their function offer exciting opportunities to evaluate the complex cross talk between microbiota, intestinal barrier, immune system and the gut-brain axis. This review summarizes these interactions in the early colonization of gastrointestinal tract with a major focus on the role of intestinal microbiota in the pathogenesis of feeding intolerance in preterm newborn. The potential benefit of early probiotic supplementation opens new perspectives in case of altered intestinal colonization at birth as preventive and therapeutic agents.
An Ecofriendly synthesis of silver nano-bioconjugates by Penicillium citrinum (MTCC9999) and its antimicrobial effect
Authors: Goswami Achintya Mohan , Sarkar Tuhin Subhra , Ghosh Sanjay 
Published: February 2013

Abstract
This report provides for the first time a novel environment friendly extracellular synthesis of stable silver nano-bioconjugates (SNBCs) at room temperature at pH 5.0 using Penicillium citrinum MTCC 9999 biomass. The UV-Visible spectral scan of dispersed SNBCs solution showed absorption in the region 340–450 nm due to surface plasma resonance (SPR). Typical Transmission Electron Microscopic (TEM) images showed that although two populations were present but most of them were in 20–30 nm range. Average zeta potential of SNBCs was −21 mV suggesting some biomolecules capped the nanoparticles imparting a net negative charge over it. FTIR analysis also showed that biomolecules were involved in stabilization. SNBCs showed strong antibacterial activity against both Gram positive (Bacillus subtilis) and Gram negative bacteria (Escherichia coli). SNBCs also showed strong antifungal activity as assessed against Schizosaccharomyces pombe. In the case of E. coli the minimum inhibitory concentrations (MIC) of SNBCs was 4 μg/ml while in B. subtilis it was 8 μg/ml. In the case of E. coli the minimum bactericidal concentrations (MBC) of SNBCs was 8 μg/ml while in B. subtilis it was 32 μg/ml. The SNBCs exerted its antibacterial and antifungal activity through generation of reactive oxygen species (ROS) inside the cell.
The influence of current speed and vegetation density on flow structure in two macrotidal eelgrass canopies
Authors: Lacy Jessica R. , Wyllie‐Echeverria Sandy 
Published: February 2013

Lay AbstractThe influence of eelgrass (Zostera marina) on near‐bed currents, turbulence, and drag was investigated at three sites in two eelgrass canopies of differing density and at one unvegetated site in the San Juan archipelago of Puget Sound, Washington, USA. The data were compared to the canopy shear‐layer model, which has been shown to describe flow through submerged vegetation in laboratory studies. Although most of the data were consistent with the model, velocity profiles from the site with lowest eelgrass density were not, particularly when currents were strong. The eelgrass attenuated tidal currents by at least 40%. Attenuation decreased with increasing current speed, and was greater than 70% at the site with greatest eelgrass density. The attenuation produces a region of low velocities within the canopy that provides a sheltered environment for zooplankton, benthic invertebrates, juvenile fishes, and microalgae. In contrast, the top of the canopy is a region of strong turbulent mixing, exhibiting large‐scale velocity fluctuations. Friction velocity (an indicator of turbulence intensity) at the canopy top was 1.5–2 times greater than at the sea floor of the unvegetated site. This strong turbulence creates a very different habitat type than within the canopy and promotes exchange of oxygen, nutrients, and organic matter between the canopy and the water above it. The eelgrass canopies generated significantly more roughness and drag than the unvegetated sea floor. The drag coefficient CD for flow over the canopies was 3–8 times greater than at the unvegetated site (0.01–0.023 vs. 2.9 × 10− 3).
Horizontal internal‐tide fluxes support elevated phytoplankton productivity over the inner continental shelf
Authors: Lucas Andrew J. , Franks Peter J. S. , Dupont Christopher L. 
Published: February 2013

Lay AbstractThe small, free‐living, photosynthetic organisms collectively called phytoplankton are the base of the oceanic food web. The phytoplankton use the energy from sunlight to convert carbon dioxide into organic carbon. Besides the necessity for sufficient light, phytoplankton also require nutrients to photosynthesize and grow. They acquire these nutrients from the dissolved pool of nutrients in the surrounding ocean. In the surface waters, where there is sufficient light for phytoplankton growth, nutrients are often in short supply and act to limit the growth of the phytoplankton. The renewal of the nutrients in the surface ocean is controlled by the physical dynamics of the upper ocean, including waves and tides, and the influence of the wind. Since the phytoplankton are limited by the availability of nutrients, the rate at which physical dynamics supply nutrients is a fundamental control on the rate of phytoplankton productivity and thus on the entire oceanic food web.In the Southern California Bight (SCB), the nutrient fluxes that regulate the productivity of the phytoplankton are caused by internal waves. Internal waves are waves that propagate through the body of the ocean much in the same way that waves propagate on the surface of the ocean. In the SCB, the most energetic internal waves are internal waves of tidal frequency, called the internal tide. The internal tide causes transport and mixing of nutrient‐rich waters from deep and offshore to shallow coastal waters. This means that coastal waters are much more productive than the surface waters offshore (these productive coastal phytoplankton populations can even be observed from space). In this article, we demonstrate quantitatively that the horizontal flux of nutrients due to the internal tide controls the productivity of the coastal ocean in Southern California.
Physical and biological controls of vertical gradients in phytoplankton
Authors: Prairie Jennifer C. , Franks Peter J. S. , Jaffe Jules S. , Doubell Mark J. , Yamazaki Hidekatsu 
Published: February 2013

Lay AbstractAs the base of the food web, phytoplankton perform vital functions in the ocean by fixing carbon through photosynthesis and by acting as prey for other organisms. Recently, scientists have observed layers of increased phytoplankton concentration in the ocean as thin as a meter or less. These findings have suggested that phytoplankton are rarely homogeneously distributed with depth, which has significant implications for predator foraging and the formation of marine snow—particles that are important to downward carbon flux. In this study, we have developed a mathematical model that describes the biological and physical mechanisms that allow these phytoplankton layers to form and persist. Our results suggest that the steepness of a phytoplankton layer is controlled by a balance of ocean mixing and the process that allowed the layer to form, such as phytoplankton growth or swimming. We then compare our model results to data of ocean mixing and phytoplankton distributions that were obtained from a free‐falling phytoplankton imaging system on a cruise in 2006.The comparison of the data to our model shows a strong fit and allows us to estimate the rate at which observed phytoplankton layers were formed. This project thus combined biological and physical measurements in the ocean with mathematical theory to provide an understanding of the mechanisms leading to phytoplankton layer formation and persistence in the ocean. This new understanding will allow us to better predict the occurrence of these features and quantify their importance to the functioning of the marine ecosystem.
Recurrent internal waves in a small lake: Potential ecological consequences for metalimnetic phytoplankton populations
Authors: Pannard Alexandrine , Beisner Beatrix E. , Bird David F. , Braun Jean , Planas Dolors , Bormans Myriam 
Published: February 2013

Lay AbstractWind mixing is one of the main factors controlling the ecology of lakes. Large, deep lakes, as well as small, shallow ones, can develop a seasonal thermal stratification. Because both light and heat come from above, a warm and illuminated surface layer develops above a colder, darker, and heavier bottom water layer under the influence of gravity. Gravity also controls the tendency for the microscopic plants that make up the floating plankton—the phytoplankton, which are a bit heavier than water—to fall from the top layer to the bottom layer, where they die and decompose, releasing the nutrients contained in their bodies. For this reason, the warmer surface layer, or epilimnion, becomes depleted in plant nutrients and the deep layer becomes enriched with nutrients. Specialized phytoplankton can grow at the interface of these two layers, leading to the development of a deep‐chlorophyll maximum in the intermediate layer known as the metalimnion. Strong winds can stir the waters of the upper layer and increase resource availability to the plankton in the upper layer in two ways. First, the mixing can bring nutrients across the metalimnion and up into the epilimnion. Second, the wind increases turbulence in the epilimnion, thereby keeping the phytoplankton suspended in the lighted layer and resuspending cells from the metalimnion. In this study, a particular consequence of wind mixing known as internal waves, which are waves that occur in the metalimnion, was observed in a small lake. These waves are caused by the wind physically pushing the warm surface layer to the downwind side of the lake, where the warm water accumulates and pushes down on the metalimnion, inducing a lakewide tilt in the metalimnion. When the wind relaxes, the waves on the surface of the lake diminish, but larger waves can be induced in the metalimnion as it tries to reestablish its equilibrium with gravity. In much the same way as plucking a guitar string can produce a primary tone as well as several overtones, the oscillation in the metalimnion has more than one frequency. This study links lake physics and ecology by characterizing the different modes of internal waves and examining the potential ecological consequences of each for phytoplankton productivity. Until now, the exploitation of internal waves by specialized phytoplankton has been thought to be important mainly in large, deep lakes. This study highlights the occurrence and ecological importance of both vertically complex internal waves and the dominance of a deep chlorophyll maximum over the entire summer stratification period in a small shallow lake.
Mussel larval responses to turbulence are unaltered by larval age or light conditions
Authors: Fuchs Heidi L. , DiBacco Claudio 
Published: February 2013

Lay AbstractWhen marine larvae change their behavior in response to small‐scale water motions, these responses potentially affect large‐scale patterns of larval dispersal and settlement. This study examined the behavior of mussel larvae (Mytilus edulis) in turbulence representative of nearshore currents. We video recorded the behavior of early‐ and late‐stage larvae in a tank with turbulence generated by two stirring grids at five turbulence levels under light and dark conditions. Water velocities and turbulence were measured using particle image velocimetry and acoustic Doppler velocimetry. We determined the vertical velocity distributions of sinking, hovering, and swimming larvae in still water and calculated the average behavioral velocity of larvae in turbulence. In still water, young larvae swam upward faster than old larvae, and both stages swam upward faster in light than in dark. In turbulence, the larval movements varied from upward swimming in weak turbulence to sinking in strong turbulence above a threshold level. At this threshold, the smallest eddy lengths were two to three times larger than the larval shell lengths, implying that turbulence is detectable even by larvae that are smaller than the smallest eddies. Responses to turbulence were unaffected by larval age or light conditions and contributed substantial behavioral variation. By sinking in strong turbulence, mussel larvae could contact the seabed more frequently in energetic coastal flows, particularly over rough materials like mussel beds. The response to turbulence by early‐stage larvae will also affect dispersal and may help larvae remain near coastal populations.
Simultaneous field measurements of ostracod swimming behavior and background flow
Authors: Sutherland K. R. , Dabiri J. O. , Koehl M. A. R. 
Published: February 2013

Lay AbstractThe sea floor is often characterized by complex topography and water flow with steep velocity gradients that vary in space and time. Organisms that live at this interface therefore contend with a wide range of water motion, from very slow flow in crevices at the substratum to fast flow some distance above in the water column. An understanding of the swimming motions of bottom‐associated zooplankton requires behavioral measurements under realistic flows in the natural environment. In the present study, we measured the swimming trajectories of marine ostracods (Paravargula trifax), which are common in benthic habitats, and the instantaneous velocity of the water with high spatial resolution (centimeters) using a compact submersible system called a self‐contained underwater velocimetry apparatus (SCUVA). The ostracods were exposed to two flow conditions: slow “ambient flow” (average speed approx. 0.4 cm s − 1) and faster “experimental flow” (average speed approx. 3.5 cm s − 1). In the faster flow, swimming tracks were less tortuous (straighter) and ostracods tended to swim more parallel to the benthos and the direction of flow compared to slower flow. Compared to modeled, passive particles that moved through the same flow treatments, ostracods moved at much higher speeds and had more tortuous tracks, thus illustrating the importance of behavior as well as environmental flow in determining ostracod swimming tracks. The numbers of encounters by ostracods with the benthos and with other ostracods were not different between the flow treatments. However, in the experimental flow treatment, interactions with other ostracods were primarily confined to the boundary layer, within several centimeters from the substratum, which may allow for enhanced mating opportunities. Further studies of the swimming behaviors of plankton in realistic environmental flows at ecologically relevant scales will enhance our understanding of how individual responses to the fluid environment correspond to population and community patterns.
A Comparison of Rapid Bacterial Methods to U.S. EPA‐Approved Methods for Biosolids
Authors: Carner Niccole , Carroll Zachary S. , Long Sharon C. 
Published: February 2013

ABSTRACT: The U.S. Environmental Protection Agency (U.S. EPA) specifies methods for testing microorganisms in biosolids, including U.S. EPA Methods 1680 and 1682 for fecal coliforms and Salmonella sp., respectively. However, these methods require 3 to 5 days to complete. For research or nonregulatory process monitoring purposes, it would be desirable to have a more rapid, less labor‐intensive method of enumerating these organisms. The purpose of this study was to compare a modified Colilert with Quanti‐Tray/2000 method to U.S. EPA Method 1680 for enumeration of fecal coliforms and E. coli, and to compare spread plating on xylose‐lysine deoxycholate (XLD) supplemented with 10 μg/L novobiocin to U.S. EPA Method 1682 for Salmonella sp. in biosolids. These alternative enumeration methods require only 1 day to complete, using fewer costly materials. This limited study indicated that the more rapid methods provide results that are statistically comparable to U.S. EPA methods under most conditions and would be acceptable for rapid, nonregulatory data collection.
A Stereocontrolled 1,2‐Addition Reaction of Tetrazoles with Alkyl Propiolates for the Synthesis of Highly Functionalized Enamines
Authors: Luo Kai , Meng Lingguo , Zhang Yicheng , Zhang Xiuli , Wang Lei 
Published: February 2013

AbstractA stereocontrolled 1,2‐addition reaction of 1‐aryl‐1H‐tetrazoles with alkyl propiolates for the synthesis of highly functionalized enamines was developed. In the presence of silver oxide (Ag2O), the 1,2‐addition reaction generated (Z)‐N‐cyano enamines in good yields with exclusive formation of the Z‐isomers. Meanwhile, the 1,2‐addition reaction generated (E)‐N‐cyano enamines in the presence of Ag2O and potassium carbonate (K2CO3) with high stereoselectivity and yields.
Carnosine Inhibits Aβ42 Aggregation by Perturbing the H‐Bond Network in and around the Central Hydrophobic Cluster
Authors: Attanasio Francesco , Convertino Marino , Magno Andrea , Caflisch Amedeo , Corazza Alessandra , Haridas Haritha , Esposito Gennaro , Cataldo Sebastiano , Pignataro Bruno , Milardi Danilo , Rizzarelli Enrico 
Published: February 2013

AbstractAggregation of the amyloid‐β peptide (Aβ) into fibrillar structures is a hallmark of Alzheimer's disease. Thus, preventing self‐assembly of the Aβ peptide is an attractive therapeutic strategy. Here, we used experimental techniques and atomistic simulations to investigate the influence of carnosine, a dipeptide naturally occurring in the brain, on Aβ aggregation. Scanning force microscopy, circular dichroism and thioflavin T fluorescence experiments showed that carnosine does not modify the conformational features of Aβ42 but nonetheless inhibits amyloid growth. Molecular dynamics (MD) simulations indicated that carnosine interacts transiently with monomeric Aβ42 by salt bridges with charged side chains, and van der Waals contacts with residues in and around the central hydrophobic cluster (17LVFFA21). NMR experiments on the nonaggregative fragment Aβ12–28 did not evidence specific intermolecular interactions between the peptide and carnosine, in agreement with MD simulations. However, a close inspection of the spectra revealed that carnosine interferes with the local propensity of the peptide to form backbone hydrogen bonds close to the central hydrophobic cluster (residues E22, S26 and N27). Finally, MD simulations of aggregation‐prone Aβ heptapeptide segments show that carnosine reduces the propensity to form intermolecular backbone hydrogen bonds in the region 18–24. Taken together, the experimental and simulation results (cumulative MD sampling of 0.2 ms) suggest that, despite the inability of carnosine to form stable contacts with Aβ, it might block the pathway toward toxic aggregates by perturbing the hydrogen bond network near residues with key roles in fibrillogenesis.
Mechanistic Insight into Catalytic Oxidation of Ammonia on Clean, O‐ and OH‐Assisted Ir(1 1 1) Surfaces
Authors: Lu Xiaoqing , Deng Zhigang , Chau Ka‐Shing , Li Longfei , Wen Zengqiang , Guo Wenyue , Wu Chi‐Man Lawrence 
Published: February 2013

AbstractPeriodic DFT calculations have been performed to systematically investigate the catalytic mechanisms of ammonia (NH3) decomposition on clean, O‐ and OH‐assisted Ir(1 1 1) surfaces. The adsorption configurations, reaction energies and barriers, and elementary steps were elaborated. Our results show that the NHx (x=1–3) decomposition prefers to proceed by means of the O‐ and OH‐assisted reaction mechanisms, NH3+O→NH2+OH, NH2+OH→NH+H2O, and NH+OH→N+H2O, rather than the direct NHx decomposition of NH3→NH2→NH→N as a result of the high energy barriers involved. The promotion effect of the O‐ and OH‐oxidizing agents are then discussed using energy barrier analysis. The relationships between the selectivity toward the final product and coverage, O to N coverage, and reaction temperature are elucidated. Finally, we compare our results with analogous investigations of NH3 decomposition on Pt, Rh, and Ir surfaces.