bluuebunny/crossref_metadata_2025 huggingface dataset:
Non-uniform annular rings-based metasurfaces for high-efficient and polarization-independent focusing
Authors: Li Tong , Wang Saisai , Zhang Xu-Lin , Deng Zi-Lan , Hang Zhi Hong , Sun Hong-Bo , Wang Guo Ping
Published: December 2015

A reflection metasurface, composed of metallic annular rings, is presented for realizing high-efficient and polarization-independent focusing. By varying the inner and outer radii of the isotropic rings, we can achieve a full modulation on the phase from −180° to 180°. By properly arranging the annular rings, we design gradient metasurfaces for focusing without polarization sensitivity by finite element method simulations and further demonstrate the focusing effect with high-efficient and polarization-independent performance experimentally in the microwave domain. In addition, the structure is also proved applicable in the optical domain by simulations. This work expands the capabilities of metasurfaces to focusing and imaging applications without polarization limitations.
Hall and Seebeck measurements estimate the thickness of a (buried) carrier system: Identifying interface electrons in In-doped SnO2 films
Authors: Papadogianni Alexandra , White Mark E. , Speck James S. , Galazka Zbigniew , Bierwagen Oliver
Published: December 2015

We propose a simple method based on the combination of Hall and Seebeck measurements to estimate the thickness of a carrier system within a semiconductor film. As an example, this method can distinguish “bulk” carriers, with homogeneous depth distribution, from “sheet” carriers, that are accumulated within a thin layer. The thickness of the carrier system is calculated as the ratio of the integral sheet carrier concentration, extracted from Hall measurements, to the volume carrier concentration, derived from the measured Seebeck coefficient of the same sample. For rutile SnO2, the necessary relation of Seebeck coefficient to volume electron concentration in the range of 3 × 1017 to 3 × 1020 cm−3 has been experimentally obtained from a set of single crystalline thin films doped with varying Sb-doping concentrations and unintentionally doped bulk samples, and is given as a “calibration curve.” Using this calibration curve, our method demonstrates the presence of interface electrons in homogeneously deep-acceptor (In) doped SnO2 films on sapphire substrates.
Absorbing metasurface created by diffractionless disordered arrays of nanoantennas
Authors: Chevalier Paul , Bouchon Patrick , Jaeck Julien , Lauwick Diane , Bardou Nathalie , Kattnig Alain , Pardo Fabrice , Haïdar Riad
Published: December 2015

We study disordered arrays of metal-insulator-metal nanoantenna in order to create a diffractionless metasurface able to absorb light in the 3–5 μm spectral range. This study is conducted with angle-resolved reflectivity measurements obtained with a Fourier transform infrared spectrometer. A first design is based on a perturbation of a periodic arrangement, leading to a significant reduction of the radiative losses. Then, a random assembly of nanoantennas is built following a Poisson-disk distribution of given density, in order to obtain a nearly perfect cluttered assembly with optical properties of a homogeneous material.
Persistent monolayer-scale chemical ordering in Si1−xGex heteroepitaxial films during surface roughening and strain relaxation
Authors: Amatya J. M. , Floro J. A.
Published: December 2015

Chemical ordering in semiconductor alloys could modify thermal and electronic transport, with potential benefits to thermoelectric properties. Here, metastable ordering that occurs during heteroepitaxial growth of Si1−xGex thin film alloys on Si(001) and Ge(001) substrates is investigated. A parametric study was performed to study how strain, surface roughness, and growth parameters affect the order parameter during the alloy growth. The order parameter for the alloy films was carefully quantified using x-ray diffraction, taking into account an often-overlooked issue associated with the presence of multiple spatial variants associated with ordering along equivalent 〈111〉 directions. Optimal ordering was observed in the films having the smoothest surfaces. Extended strain relaxation is suggested to reduce the apparent order through creation of anti-phase boundaries. Ordering surprisingly persists even when the film surface extensively roughens to form {105} facets. Growth on deliberately miscut Si(001) surfaces does not affect the volume-averaged order parameter but does impact the relative volume fractions of the equivalent ordered variants in a manner consistent with geometrically necessary changes in step populations. These results provide somewhat self-contradictory implications for the role of step edges in controlling the ordering process, indicating that our understanding is still incomplete.
Millikelvin cooling by heavy-fermion-based tunnel junctions
Authors: Prest Martin , Min Gao , Whall Terry
Published: December 2015

This paper addresses a high-performance electron-tunneling cooler based on a novel heavy-fermion/insulator/superconductor junction for millikelvin cooling applications. We show that the cooling performance of an electronic tunneling refrigerator could be significantly improved using a heavy-fermion metal to replace the normal metal in a conventional normal metal/insulator/superconductor junction. The calculation, based on typical parameters, indicates that, for a bath temperature of 300 mK, the minimum cooling temperature of an electron tunneling refrigerator is reduced from around 170 mK to below 50 mK if a heavy-fermion metal is employed in place of the normal metal. The improved cooling is attributed to an enhancement in electron tunneling due to the existence of a resonant density of states at the Fermi level.
Experimental investigation on the energy deposition and expansion rate under the electrical explosion of aluminum wire in vacuum
Authors: Shi Zongqian , Wang Kun , Shi Yuanjie , Wu Jian , Han Ruoyu
Published: December 2015

Experimental investigations on the electrical explosion of aluminum wire using negative polarity current in vacuum are presented. Current pulses with rise rates of 40 A/ns, 80 A/ns, and 120 A/ns are generated for investigating the influence of current rise rate on energy deposition. Experimental results show a significant increase of energy deposition into the wire before the voltage breakdown with the increase of current rise rate. The influence of wire dimension on energy deposition is investigated as well. Decreasing the wire length allows more energy to be deposited into the wire. The energy deposition of a 0.5 cm-long wire explosion is ∼2.5 times higher than the energy deposition of a 2 cm-long wire explosion. The dependence of the energy deposition on wire diameter demonstrates a maximum energy deposition of 2.7 eV/atom with a diameter of ∼18 μm. Substantial increase in energy deposition is observed in the electrical explosion of aluminum wire with polyimide coating. A laser probe is applied to construct the shadowgraphy, schlieren, and interferometry diagnostics. The morphology and expansion trajectory of exploding products are analyzed based on the shadowgram. The interference phase shift is reconstructed from the interferogram. Parallel dual wires are exploded to estimate the expansion velocity of the plasma shell.
Compact turnkey focussing neutron guide system for inelastic scattering investigations
Authors: Brandl G. , Georgii R. , Dunsiger S. R. , Tsurkan V. , Loidl A. , Adams T. , Pfleiderer C. , Böni P.
Published: December 2015

We demonstrate the performance of a compact neutron guide module which boosts the intensity in inelastic neutron scattering experiments by approximately a factor of 40. The module consists of two housings containing truly curved elliptic focussing guide elements, positioned before and after the sample. The advantage of the module lies in the ease with which it may be reproducibly mounted on a spectrometer within a few hours, on the same timescale as conventional sample environments. It is particularly well suited for samples with a volume of a few mm3, thus enabling the investigation of materials which to date would have been considered prohibitively small or samples exposed to extreme environments, where there are space constraints. We benchmark the excellent performance of the module by measurements of the structural and magnetic excitations in single crystals of model systems. In particular, we report the phonon dispersion in the simple element lead. We also determine the magnon dispersion in the spinel ZnCr2Se4 (V = 12.5 mm3), where strong magnetic diffuse scattering at low temperatures evolves into distinct helical order.
Transport of fast electrons in a nanowire array with collisional effects included
Authors: Li Boyuan , Zhang Zhimeng , Wang Jian , Zhang Bo , Zhao Zongqing , Shan Lianqiang , Zhou Weimin , Cao Lihua , Zhang Baohan , Gu Yuqiu
Published: December 2015

The transport of picosecond laser generated fast electrons in a nanowire array is studied with two-dimensional particle-in-cell simulations. Our simulations show that a fast electron beam is initially guided and collimated by strong magnetic filaments in the array. Subsequently, after the decomposition of the structure of nanowire array due to plasma expansion, the beam is still collimated by the resistive magnetic field. An analytical model is established to give a criterion for long-term beam collimation in a nanowire array; it indicates that the nanowire cell should be wide enough to keep the beam collimated in picosecond scale.
Ultrafast optical control of magnetization dynamics in polycrystalline bismuth doped iron garnet thin films
Authors: Deb Marwan , Vomir Mircea , Rehspringer Jean-Luc , Bigot Jean-Yves
Published: December 2015

Controlling the magnetization dynamics on the femtosecond timescale is of fundamental importance for integrated opto-spintronic devices. For industrial perspectives, it requires to develop simple growth techniques for obtaining large area magneto-optical materials having a high amplitude ultrafast Faraday or Kerr response. Here we report on optical pump probe studies of light induced spin dynamics in high quality bismuth doped iron garnet polycrystalline film prepared by the spin coating method. We demonstrate an ultrafast non-thermal optical control of the spin dynamics using both circularly and linearly polarized pulses.
Fast–slow continuum and reproductive strategies structure plant life-history variation worldwide
Authors: Salguero-Gómez Roberto , Jones Owen R. , Jongejans Eelke , Blomberg Simon P. , Hodgson David J. , Mbeau-Ache Cyril , Zuidema Pieter A. , de Kroon Hans , Buckley Yvonne M.
Published: December 2015

Significance

Schedules of survival, growth, and reproduction define life-history strategies across species. Understanding how life-history strategies are structured is fundamental to our understanding of the evolution, abundance, and distribution of species. We found that life-history strategies of 418 plant species worldwide are explained by an axis representing the pace of life and another representing the wide range of reproductive strategies. This framework predicts responses to perturbations and long-term population performance, showing great promise as a predictive tool for plant population responses to environmental change.
Regulation of neural gene transcription by optogenetic inhibition of the RE1-silencing transcription factor
Authors: Paonessa Francesco , Criscuolo Stefania , Sacchetti Silvio , Amoroso Davide , Scarongella Helena , Pecoraro Bisogni Federico , Carminati Emanuele , Pruzzo Giacomo , Maragliano Luca , Cesca Fabrizia , Benfenati Fabio
Published: December 2015

Significance

Repressor element 1-silencing transcription factor (REST) is a transcriptional repressor that regulates nervous system development. Normally expressed at low levels by mature neurons, REST is up-regulated in various brain pathologies. Using a light-sensitive domain from the oat plant (
Avena sativa
), we engineered novel optogenetic proteins that inhibit REST activity when illuminated by blue light, thus obtaining the spatial and temporal control of the transcription of REST target genes. This approach may have an impact in the development of new therapies for all the diseases in which REST is dysregulated, such as epilepsy, ischemia, and cancers of various origin, as such therapies may counteract the long-term changes in gene expression that take place in the context of the pathological brain.
Functional hierarchy underlies preferential connectivity disturbances in schizophrenia
Authors: Yang Genevieve J. , Murray John D. , Wang Xiao-Jing , Glahn David C. , Pearlson Godfrey D. , Repovs Grega , Krystal John H. , Anticevic Alan
Published: December 2015

Significance

Schizophrenia is linked to widespread neuronal-level changes causing cortical excitation-inhibition imbalance. However, functional neuroimaging reveals preferential association network dysconnectivity. Therefore, a tension exists between two competing frameworks: global versus localized neural dysfunction in schizophrenia. To link these levels of analysis, this study initially simulated cellular-level glutamatergic deficits, generating network-level predictions of cortical imbalance. Schizophrenia results revealed widespread hyperconnectivity in line with model predictions, yet effects were most profound within association networks. These clinical effects were computationally captured by considering a pre-existing functional cortical hierarchy between association and sensory regions. This study reveals that widespread cellular deficits in schizophrenia can give rise to network-preferential disruptions observed in neuroimaging as an emergent property of pre-existing functional differences between cortical areas.
Aquatic carbon cycling in the conterminous United States and implications for terrestrial carbon accounting
Authors: Butman David , Stackpoole Sarah , Stets Edward , McDonald Cory P. , Clow David W. , Striegl Robert G.
Published: December 2015

Significance

Inland waters provide habitat for aquatic organisms; are sources of human drinking water; and integrate, transport, and process carbon across continents. Estimates of the accumulation of carbon in terrestrial environments suggest that agricultural and forest ecosystems have annual net gains in carbon storage. These ecosystems are considered sinks of atmospheric carbon dioxide. None of these estimates have considered the loss of carbon to and also through aquatic environments at the national or continental scale. We show that aquatic ecosystems in the conterminous United States export over 100 teragrams of carbon (TgC) per year, highlighting the need to attribute the sources of aquatic carbon more accurately, and assert that inland waters play an important role in carbon accounting.
Nicastrin functions to sterically hinder γ-secretase–substrate interactions driven by substrate transmembrane domain
Authors: Bolduc David M. , Montagna Daniel R. , Gu Yongli , Selkoe Dennis J. , Wolfe Michael S.
Published: December 2015

Significance

γ-Secretase is a conserved and ubiquitous intramembrane-cleaving protease (I-CLiP). Its normal function is required for proper notch signaling, and its processing of amyloid precursor protein is implicated in Alzheimer’s disease. Although γ-secretase has over 90 reported substrates, little is known about the mechanism by which γ-secretase recruits its substrates while at the same time distinguishing substrate from nonsubstrate within the protein-crowded environment of cellular membranes. In contrast to previous studies, our data demonstrate that substrate transmembrane domain drives its interaction with γ-secretase. We find that the γ-secretase component nicastrin acts to sterically block substrates with large ectodomains from interacting with γ-secretase, providing the mechanism by which γ-secretase selectively recruits ectodomain-shed substrates while also preventing cleavage of nonsubstrates.
TLR4-activated microglia require IFN-γ to induce severe neuronal dysfunction and death in situ
Authors: Papageorgiou Ismini E. , Lewen Andrea , Galow Lukas V. , Cesetti Tiziana , Scheffel Jörg , Regen Tommy , Hanisch Uwe-Karsten , Kann Oliver
Published: December 2015

Significance

Microglia (brain macrophages) become rapidly activated in most neuropsychiatric disorders. A popular concept is that a single pathogenic stimulus, such as bacterial lipopolysaccharide (LPS) through Toll-like receptor 4 (TLR4), is sufficient to induce a reactive proinflammatory phenotype in microglia that exerts neurotoxicity. This concept is biologically risky, however. Here we provide evidence that chronic activation with either LPS or the leukocyte cytokine IFN-γ induces different reactive phenotypes in microglia of postnatal hippocampal tissue. Notably, these phenotypes only moderately alter diverse neuronal functions. In contrast, coactivation of TLR4 and IFN-γ receptors results in massive neural dysfunction and death. Thus, activation of TLR4 in microglia in situ requires concomitant IFN-γ signaling from other host immune cells to induce neurodegeneration.
Estimating the reliability of eyewitness identifications from police lineups
Authors: Wixted John T. , Mickes Laura , Dunn John C. , Clark Steven E. , Wells William
Published: December 2015

Significance

In contrast to prior research, recent studies of simulated crimes have reported that (
i
) eyewitness confidence can be a strong indicator of accuracy and (
ii
) traditional simultaneous lineups may be diagnostically superior to sequential lineups. The significance of our study is that these issues were investigated using actual eyewitnesses to a crime. Recent laboratory trends were confirmed: Eyewitness confidence was strongly related to accuracy, and simultaneous lineups were, if anything, diagnostically superior to sequential lineups. These results suggest that recent reforms in the legal system, which were based on the results of older research, may need to be reevaluated.
Harnessing RNAi-based nanomedicines for therapeutic gene silencing in B-cell malignancies
Authors: Weinstein Shiri , Toker Itai A. , Emmanuel Rafi , Ramishetti Srinivas , Hazan-Halevy Inbal , Rosenblum Daniel , Goldsmith Meir , Abraham Avigdor , Benjamini Ohad , Bairey Osnat , Raanani Pia , Nagler Arnon , Lieberman Judy , Peer Dan
Published: December 2015

Significance

RNA interference (RNAi) holds great promise as a novel therapeutic approach. Small interfering RNAs (siRNAs) that manipulate gene expression in leukocytes could be used to treat blood cancers. However, the lack of strategies for delivering siRNAs to leukocytes systemically has hampered the development of RNAi-based therapeutics. Here, we show that lipid-based nanoparticles coated with anti-CD38 monoclonal antibodies specifically target mantle cell lymphoma (MCL) cells and induce cell-specific therapeutic gene silencing in vivo. CD38-targeted nanoparticles that contain cyclin D1 siRNAs prolong survival of mice bearing MCL lymphomas in the bone marrow. This strategy opens a new avenue for treating MCL that might be applied to other hematological malignancies.
Mesenchymal stem/stromal cells precondition lung monocytes/macrophages to produce tolerance against allo- and autoimmunity in the eye
Authors: Ko Jung Hwa , Lee Hyun Ju , Jeong Hyun Jeong , Kim Mee Kum , Wee Won Ryang , Yoon Sun-ok , Choi Hosoon , Prockop Darwin J. , Oh Joo Youn
Published: December 2015

Significance

Mesenchymal stem/stromal cells (MSCs) are the focus of intensive efforts directed at developing cell-based therapies in immunologic disorders. However, one of the paradoxical observations made so far is that MSCs engraft transiently in the recipient after exogenous infusion, but achieve long-term therapeutic benefits. Here we demonstrate that MSCs induce the immune tolerance by activating endogenous immune regulatory system of the recipient. Specifically, i.v. administered MSCs induce a population of regulatory monocytes/macrophages in the lung, which are capable of suppressing allo- and autoimmune responses independently of regulatory T cells. The data provide a mechanistic insight into the action of MSCs in immunologic disorders, one of the most frequent indications of diseases for clinical trials using stem cells.
Structural foundations of optogenetics: Determinants of channelrhodopsin ion selectivity
Authors: Berndt Andre , Lee Soo Yeun , Wietek Jonas , Ramakrishnan Charu , Steinberg Elizabeth E. , Rashid Asim J. , Kim Hoseok , Park Sungmo , Santoro Adam , Frankland Paul W. , Iyer Shrivats M. , Pak Sally , Ährlund-Richter Sofie , Delp Scott L. , Malenka Robert C. , Josselyn Sheena A. , Carlén Marie , Hegemann Peter , Deisseroth Karl
Published: December 2015

Significance

Channelrhodopsins are membrane proteins that enable cellular regulation of transmembrane ion conductance through light-gated pores; these proteins have found application in optogenetics. This paper tests the hypothesis that selectivity of channelrhodopsins is determined by surface potential of the pore region: Cations are conducted by a negatively charged pore, and chloride ions are conducted by a pore that has neutral and positively charged residues. In confirming this hypothesis and applying the resulting principles, we engineer improved chloride-conducting channels with higher chloride selectivity and conductivity. We also provide insights into the distinct mechanisms underlying inhibition mediated by higher-efficiency chloride channels compared with ion pumps. Finally, we demonstrate initial utility of light-gated microbial opsin-based chloride channels in controlling behavior of freely moving animals.
Fish Assemblage Associations with Floodplain Connectivity Following Restoration to Benefit an Endangered Catostomid
Authors: Landress Chad M.
Published: December 2015

The dynamics of stream and floodplain connectivity are a growing consideration for restoration projects. Restoration of a tributary stream to Utah Lake was undertaken in 2008 with the intent of increasing available spawning and nursery habitat for the endangered June Sucker Chasmistes liorus. Restoration efforts provided an opportunity to evaluate relationships between fish assemblages and variables related to the physiochemical environment, vegetation, and habitat connectivity at floodplain ponds. Fish were collected with beach seines and habitat variables were measured each month at 12 floodplain ponds during March 2010 to March 2011. Total catch was predominated by nonnative species: Green Sunfish Lepomis cyanellus, Western Mosquitofish Gambusia affinis, Black Bullhead Ameiurus melas, Fathead Minnow Pimephales promelas, and Bluegill Lepomis macrochirus. Both indirect and direct gradient analyses indicated a significant correlation between fish assemblages and site connectivity. The percentage and type of macrophyte cover (e.g., emergent, submergent) also played a significant role in structuring fish assemblages. Species richness was generally higher at sites with intermediate to high connectivity than at sites with lower connectivity. Sites with lower connectivity were predominated by Green Sunfish, Mosquitofish, and Fathead Minnow. June Suckers were collected from sites with intermediate values of connectivity and vegetation. Observed patterns suggested connectivity structured initial fish assemblages and macrophyte colonization dynamics; subsequent interactions between local habitat (i.e., percent vegetation) and biotic factors (e.g., competition, predation, etc.) provided site‐specific interactions and structure. The results of this study indicate connectivity dynamics should be an important consideration in stream and floodplain restoration efforts.
Effect of Species Assemblage on Juvenile Growth and Condition in Three California Estuarine Fishes
Authors: Chase D. A. , Todgham A. E.
Published: December 2015

We investigated the physiological response of the endangered Tidewater Goby Eucyclogobius newberryi to the presence of Threespine Sticklebacks Gasterosteus aculeatus (native to California) and Rainwater Killifish Lucania parva (nonnative). A fully factorial experimental design was used to examine species assemblage effects on juvenile fish over a 28‐d period. Growth characteristics (weight, SL, and relative condition factor [Kn]) and stress hormone levels (cortisol) were assessed under ample food conditions and at a salinity of 15‰. Weight and SL of Tidewater Goby increased throughout the experiment; growth did not differ in relation to fish assemblage treatment, but significant differences in growth were observed between sampling dates within the experiment. Rainwater Killifish exhibited marginal increases in weight, SL, and Kn, but these increases were not different among assemblage treatments or over time. For Threespine Sticklebacks, weight and SL increased during the final 2 weeks of the experiment, resulting in significant differences over the entire experimental period; however, growth characteristics of this species did not differ among assemblage treatments. Cortisol levels in all three species were not significantly affected by assemblage treatment. The present results indicate that juvenile Tidewater Goby are not adversely affected by native Threespine Sticklebacks or nonnative Rainwater Killifish under stable abiotic conditions in the absence of food limitation.
Electrospray deposition of SnO2 films from precursor solution
Authors: Gürbüz Mevlüt , Günkaya Göktuğ , Doğan Aydın
Published: December 2015

The electrospray deposition (ESD) of SnO2 films from SnCl4.5H2O precursor solution was performed for gas sensor applications. Deposition time, solution flow rate and solution concentration were the main control parameters in the ESD process. The morphological properties of the deposited films were characterised by scanning electron microscopy. X-ray diffraction and energy dispersive X-ray analyses were employed to confirm the crystal phases and composition of the films. The best coatings with an island of particle agglomerates were observed at a flow rate of 0.12 ml min−1, for 60 min, and at a 0.05M concentration. The crystallisation of SnO2 films was observed at 650°C. The grain size and surface morphology of the films were influenced by the sol concentrations. Larger grain size and cracked surface were observed by increasing the sol concentration. The film thickness of 6 µm and a grain size of less than 100 nm were achieved.
Active recovery of the finger flexors enhances intermittent handgrip performance in rock climbers
Authors: Baláš Jiří , Michailov Michail , Giles David , Kodejška Jan , Panáčková Michaela , Fryer Simon
Published: December 2015

This study aimed to (1) evaluate the effect of hand shaking during recovery phases of intermittent testing on the time–force characteristics of performance and muscle oxygenation, and (2) assess inter‐individual variability in the time to achieve the target force during intermittent testing in rock climbers. Twenty‐two participants undertook three finger flexor endurance tests at 60% of their maximal voluntary contraction until failure. Performances of a sustained contraction and two intermittent contractions, each with different recovery strategies, were analysed by time–force parameters and near‐infrared spectroscopy. Recovery with shaking of the forearm beside the body led to a significantly greater intermittent test time (↑ 22%, P < .05), force–time integral (↑ 28%, P < .05) and faster muscle re‐oxygenation (↑ 32%, P < .05), when compared to the hand over hold condition. Further, the ratio of intermittent to continuous test time distinguished specific aerobic muscular adaptations among sport climbers (2.02), boulderers (1.74) and lower grade climbers (1.25). Lower grade climbers and boulderers produced shorter duration contractions due to the slower development of target force during the intermittent test, indicating worse kinaesthetic differentiation. Both the type of recovery and climbing discipline determined muscle re‐oxygenation and intermittent performance in rock climbers.
Evaluating Policy Design Choices for the Margin Protection Program for Dairy Producers: An Expected Indemnity Approach
Authors: Newton John , Thraen Cameron S. , Bozic Marin
Published: December 2015

The Agricultural Act of 2014 replaced dairy product price supports and countercyclical income support payments with the Margin Protection Program for Dairy Producers. Using farm‐level data, producer decisions and aggregate policy costs under a variety of risk environments and policy design alternatives are simulated. Fixed premium rates may result in budget outlays that are substantially higher than for equivalent variable‐rate insurance subsidized at levels observed in revenue‐based crop insurance policies. Due to the absence of adjusted gross income or production eligibility constraints, a significant portion of benefits may accrue to a small share of large dairy farms.
We should not assume that fishing jellyfish will solve our jellyfish problem
Authors: Gibbons M. J. , Boero F. , Brotz L.
Published: December 2015

Whether jellyfish are increasing or not in the global ocean is a subject of some debate, but the fact remains that when they bloom, jellyfish can negatively affect local economies. Despite this, there has been no robust debate about the idea of deliberately removing jellyfish as a means of population control. Here, we discuss the effects of fishing for jellyfish, either as a sustainable resource and/or as a way to simply reduce their nuisance value, on both individual jellyfish populations and the ecosystem. Given that the drivers influencing each local bloom are different, or that the effects of more widespread drivers may be manifested differently at each locale, our priority at population control/use needs to be more basic research on jellyfish. While we do not advocate a no-fishing approach, we emphasize the need to be cautious in embracing jellyfish fisheries as a panacea and we need to consider the management of each bloom on a case-by-case basis.
Decades of habitat use reveal food limitation of Newfoundland caribou
Authors: Schaefer James A. , Mahoney Shane P. , Weir Jackie N. , Luther J. Glenn , Soulliere Colleen E.
Published: December 2015

Identifying limiting factors is fundamental to understanding and conserving mammals, yet it often requires long-term data for long-lived species. Numerical changes of migratory caribou ( Rangifer tarandus ), for example, may unfold over decades, but few studies have examined habitat use at similar timeframes. We analyzed multiple decades of habitat use by caribou in Newfoundland, Canada, coincident with their numeric growth ( r = 0.064 in 1980s, 1990s) and decline ( r = −0.099 in 2000s). We examined 2 scales: selection of land cover, based on radiotracking of 520 adult females, and diet, based on microhistological analysis of feces and age-specific tooth wear from jawbones of harvested animals. Caribou responded at both scales. In contrast to previous decades, females during the population decline used proportionally less open coniferous and closed coniferous forests, they used more shrublands (in fall and winter) and barrens, open habitats with greater vascular plant resources. Patterns of selection also changed from nonselection to avoidance of open coniferous forest and from avoidance to nonselection or preference of barrens. The proportion of dietary moss increased at the expense of deciduous shrubs, especially during spring and summer and of ericaceous shrubs, graminoids, and lichens during winter. Teeth of both sexes exhibited premature wear, likely indicative of abrasion from low-quality forages and cropping of foods near the ground. These patterns mirror other responses, including declines in calf weight, female body size, number of male antler points, herd affinities, and time spent on the summer grounds. We surmise that they reflect density-dependent forage limitation of this island population.
Addressing the Interprofessional Collaboration Competencies of the Association of American Medical Colleges: A Systematic Review of Assessment Instruments in Undergraduate Medical Education
Authors: Havyer Rachel D. , Nelson Darlene R. , Wingo Majken T. , Comfere Nneka I. , Halvorsen Andrew J. , McDonald Furman S. , Reed Darcy A.
Published: December 2015

Purpose

To summarize characteristics and validity evidence of tools that assess teamwork in undergraduate medical education (UME), and provide recommendations for addressing the interprofessional collaboration competencies of the Association of American Medical Colleges (AAMC).

Method

The authors conducted a systematic review, searching MEDLINE, MEDLINE In-process, CINAHL, and PsycINFO from January 1, 1979, through April 1, 2014; they searched reference lists and national meeting abstracts. They included original research reports that described a quantitative tool used to assess teamwork in UME. They abstracted characteristics and validity evidence for the tools, plus study quality, according to established frameworks. Two authors independently abstracted 25% of articles and calculated agreement. Authors then applied predefined criteria to identify tools best suited to address the AAMC’s teamwork competencies.

Results

Of 13,549 citations, 70 articles describing 64 teamwork assessment tools were included. Of these 64 tools, 27 (42%) assessed teamwork in classroom, 31 (48%) in simulation, and only 7 (11%) in actual clinical settings. The majority (47; 73%) of tools assessed medical students’ teamwork in interprofessional teams. On the basis of content concordance, strength of validity evidence, generalizability of scores, and level of outcomes, four published tools were recommended to assess the AAMC’s teamwork competencies: the Collaborative Healthcare Interdisciplinary Relationship Planning Scale, Readiness for Interprofessional Learning Scale, Communication and Teamwork Skills assessment, and Teamwork Mini-Clinical Evaluation Exercise.

Conclusions

Substantial validity evidence supports the use of several UME teamwork assessments. Four tools have been appropriately designed and sufficiently studied to constitute appropriate assessments of the AAMC’s teamwork competencies.
All Health Is Global Health, All Medicine Is Social Medicine: Integrating the Social Sciences Into the Preclinical Curriculum
Authors: Kasper Jennifer , Greene Jeremy A. , Farmer Paul E. , Jones David S.
Published: December 2015

As physicians work to achieve optimal health outcomes for their patients, they often struggle to address the issues that arise outside the clinic. Social, economic, and political factors influence patients’ burden of disease, access to treatment, and health outcomes. This challenge has motivated recent calls for increased attention to the social determinants of health. At the same time, advocates have called for increased attention to global health. Each year, more U.S. medical students participate in global health experiences. Yet, the global health training that is available varies widely. The discipline of social medicine, which attends to the social determinants of disease, social meanings of disease, and social responses to disease, offers a solution to both challenges. The analyses and techniques of social medicine provide an invaluable toolkit for providing health care in the United States and abroad.

In 2007, Harvard Medical School implemented a new course, required for all first-year students, that teaches social medicine in a way that integrates global health. In this article, the authors argue for the importance of including social medicine and global health in the preclinical curriculum; describe Harvard Medical School’s innovative, integrated approach to teaching these disciplines, which can be used at other medical schools; and explore the barriers that educators may face in implementing such a curriculum, including resistance from students. Such a course can equip medical students with the knowledge and tools that they will need to address complex health problems in the United States and abroad.
Factors Associated With Receipt of Radiation Therapy for Rectal Cancer
Authors: McClure Laura A. , Sussman Daniel A. , Hernandez Monique N. , Tannenbaum Stacey L. , Yechieli Raphael L. , Bonner Judith M. , Zheng D. Diane , Lee David J.
Published: December 2015

Purpose:

Appropriate treatment for cancer is vital to increasing the likelihood of survival; however, for rectal cancer, there are demonstrated disparities in receipt of treatment by race/ethnicity and socioeconomic status. We evaluated factors associated with receipt of appropriate radiation therapy for rectal cancer using data from the Florida Cancer Data System that had been previously enriched with detailed treatment information collected from a Centers for Disease Control and Prevention Comparative Effectiveness Research study. This treatment information is not routinely available in cancer registry data and represents a unique data resource.

Materials and Methods:

Using multivariable regression, we evaluated factors associated with receiving radiation therapy among rectal cancer cases stage II/III. Our sample (n=403) included cases diagnosed in Florida in 2011 who were 18 years and older. Cases clinically staged as 0/I/IV were excluded.

Results:

Older age (odds ratio=0.96; 95% confidence interval, 0.94-0.97), the presence of one or more comorbidities (0.61; 0.39-0.96), and receipt of surgical intervention (0.44; 0.22-0.90) were associated with lack of radiation.

Conclusions:

In this cohort of patients, sociodemographic factors such as race/ethnicity, insurance status, and socioeconomic status, did not influence the receipt of radiation. Further research is needed, however, to understand why aging, greater comorbidity, and having surgery present a barrier to radiation therapy, particularly given that it is a well-tolerated treatment in most patients.
Correlation Between Standardized Uptake Value in Preneoadjuvant and Postneoadjuvant Chemoradiotherapy and Tumor Regression Grade in Patients With Locally Advanced Esophageal Cancer
Authors: Baksh Kathryn , Prithviraj Gopi , Kim Youngchul , Hoffe Sarah , Shridhar Ravi , Coppola Domenico , Centeno Barbara , Pimiento Jose , Meredith Kenneth , Almhanna Khaldoun
Published: December 2015

Purpose:

To investigate whether positron emission tomography/computed tomography (PET/CT) initial and restaging imaging predicts for pathologic response measured by tumor regression grade (TRG) after preoperative chemoradiotherapy (CRT) in patients with locally advanced esophageal cancer.

Methods:

A retrospective review of 220 patients with stage II-III esophageal cancer treated with neoadjuvant CRT followed by surgery was performed. In total, 187 patients were eligible for statistical analysis. Pretreatment and posttreatment PET/CT scans were reviewed. Maximum standard uptake value (SUV) at the site of the primary tumor was recorded before and 6 weeks after neoadjuvant therapy. Upon completion of surgery, TRG was determined by a specialized site-specific gastrointestinal pathologist. Spearman correlation was used to compare pre, post, and change in maximum SUV, TRG, and overall survival.

Results:

The median follow-up was 24 months. Although no significant correlation was found between pretreatment SUV and TRG (r=0.073, P=0.32), post-CRT SUV, however, showed a significant positive correlation with TRG (r=0.374, P<0.01). There was no significant correlation between the absolute change in fluorodeoxyglucose uptake after CRT and TRG (r=0.057, P=0.44); however, the rate of SUV change showed a significant correlation with TRG (r=0.178, P=0.017). Similar to previous studies, our study showed a significant difference in overall survival between TRG groups (log-rank test, P=0.019). Patients with TRG 3 showed prominently worse survival with median survival of 27.4 months. Patients with favorable pathologic responses were those whose scans demonstrated a metabolic response defined as a decrease in SUV≥70%.

Conclusions:

Changes in SUV uptake on PET/CT scans after CRT have prognostic value in predicting pathologic response of esophageal cancer after neoadjuvant therapy. Further studies are needed to validate the integration of PET/CT as a decision-making tool.
Ilex paraguariensis hydroalcoholic extract exerts antidepressant-like and neuroprotective effects: involvement of the NMDA receptor and the l-arginine-NO pathway
Authors: Ludka Fabiana K. , Tandler Lori de Fátima , Kuminek Gislaine , Olescowicz Gislaine , Jacobsen Jonatha , Molz Simone
Published: December 2015

Ilex paraguariensis St. Hilaire (Aquifoliaceae) is a typical plant from South America. Preclinical studies have reported the effect of I. paraguariensis-based preparations on different alterations in the brain. This study aimed to examine the antidepressant-like and neuroprotective effects of I. paraguariensis hydroalcoholic extract (IpHE). The role of the N-methyl-d-aspartate receptor and the l-arginine-nitric oxide pathway in the IpHE antidepressant-like effect was also evaluated. Using the tail suspension test, we showed that IpHE (0.1–10 mg/kg, orally) exerts an antidepressant-like effect similar to that of ketamine (1 mg/kg, intraperitoneally). The antidepressant-like effect depends on the N-methyl-d-aspartate receptor and l-arginine-nitric oxide pathway modulation as we observed a combinatory effect using subeffective doses of IpHE (0.01 mg/kg, orally) and ketamine (0.1 mg/kg, intraperitoneally) or MK-801 (0.001 mg/kg, intraperitoneally). Also, pretreatment of mice with l-arginine (750 mg/kg, intraperitoneally) abolished the antidepressant-like effect of IpHE. This effect coincides with the neuroprotective effect, given that glutamate toxicity (10 mmol/l) did not decrease cell viability in hippocampal or cortical slices from IpHE-treated mice. The chromatographic profile of IpHE showed the presence of the methylxanthines caffeine and theobromine. Administration of methylxanthines (2.7 µg/kg) in mice produced an antidepressant-like effect, but not neuroprotection. We suggest that methylxanthines are at least in part responsible for the antidepressant-like effect of IpHE; further studies are necessary to determine the biological compounds responsible for the neuroprotective effect.
Prognosis of overt disseminated intravascular coagulation in patients admitted to a medical emergency department
Authors: Schwameis Michael , Buchtele Nina , Schober Andreas , Schoergenhofer Christian , Quehenberger Peter , Jilma Bernd
Published: December 2015

Objective

To assess the prevalence, characteristics and prognosis of overt disseminated intravascular coagulation (DIC) in adult emergency department (ED) patients and identify markers of poor outcome.

Materials and methods

In a chart review study, we analysed the occurrence of overt DIC in all patients (n=1 001 727) attending the University’s ED from 2003 to 2014 applying the ISTH DIC score. The primary outcome measure was 30-day mortality. Logistic regression analysis was used to determine predictors of mortality.

Results

The initial inter-rater reliability in the diagnosis of DIC was 0.85 [κ; 95% confidence interval (CI), 0.77–0.92]. The main DIC precipitators were malignancy (47%), cardiovascular diseases (CVD, 27%) and sepsis (16%). Hyperfibrinolytic DIC occurred in 27% of patients and was over-represented in those with cardiac arrest (68%). Thirty-day mortality (52%) was inversely associated with fibrinogen levels on admission [adjusted odds ratio, 0.49; 95% CI: 0.30–0.82; P=0.006]. Afibrinogenaemia implied an even 10-fold increased risk of dying (crude odds ratio, 10.0; 95% CI: 3.2–31.4; P<0.001). D-dimer and platelet count had no predictive value. Appropriate ICD-10 coding for DIC was present in only 1.8% of cases.

Conclusion

Overt DIC is a rare but underdiagnosed event in ED patients. In this collective, cardiac arrest is a dominant cause of DIC presenting with a fibrinolytic phenotype. The degree of hypofibrinogenaemia on admission strongly and linearly predicted early death.
Acute Recurrent Pancreatitis in Children
Authors: Pant Chaitanya , Sferra Thomas J. , Lee Brian R. , Cocjin Jose T. , Olyaee Mojtaba
Published: December 2015

We investigated acute recurrent pancreatitis (ARP) in children using a national health care database. From 2002 to 2014, 26,435 children had a diagnosis of acute pancreatitis (AP); 10,648 discharges were index hospitalizations. A total of 6159 children had a single hospitalization for AP, whereas 4489 (42%) children underwent 15,787 rehospitalizations. Children experienced a median of 2 ARP‐related hospitalizations with a median time between admissions of 86 days. Younger patients with a more severe index episode of AP were at a higher risk of ARP. ARP‐related hospitalizations had an increased requirement for intensive care unit care compared with an index episode of AP.
Clinical Features and Risk Factors of Autoimmune Liver Involvement in Pediatric Inflammatory Bowel Disease
Authors: Bramuzzo Matteo , Martelossi Stefano , Torre Giuliano , Cardile Sabrina , Arrigo Serena , Vignola Silvia , Ferrari Federica , Zuin Giovanna , Illiceto Maria Teresa , Gasparetto Marco , Pellegrino Salvatore , Romano Claudio , Maggiore Giuseppe , Montico Marcella , Aloi Marina ,   SIGENP IBD Group
Published: December 2015

Objectives:

Autoimmune liver disease is reported in up to 7.8% of children with inflammatory bowel disease. A distinct inflammatory bowel disease phenotype has been suggested in adults and in small pediatric cohorts. The aim of the study was to evaluate the features of inflammatory bowel disease associated with autoimmune liver diseases and to analyze the characteristics of the liver disease.

Methods:

Information on patients was obtained from the Italian Pediatric Inflammatory Bowel Disease Registry. Data of patients with and without autoimmune liver disease were compared.

Results:

Autoimmune liver disease was detected in 6.8% of the 677 patients enrolled and was significantly associated with the diagnosis of ulcerative colitis (83%), with pancolonic involvement (84%), and with perinuclear antineutrophil cytoplasmic antibody positivity (41%) (all Ps < 0.05). Autoimmune liver disease was defined as sclerosing cholangitis in 61% of the patients and as an overlap syndrome in 33%. Concomitant intra‐ and extrahepatic biliary involvement was reported in 61% of cases, whereas exclusive extrahepatic lesions were reported in 21%. Hepatobiliary complications were observed in 9% of the patients during follow‐up.

Conclusions:

Autoimmune liver disease, especially sclerosing cholangitis, was significantly more common in patients with extensive ulcerative colitis. Although complications are relatively rare in the pediatric age, monitoring is recommended.
Clinical Features of Focal Nodular Hyperplasia of the Liver in Children
Authors: Ji Yi , Chen Siyuan , Xiang Bo , Wen Tianfu , Yang Jiaying , Zhong Lin , Li Fuyu , Li Li
Published: December 2015

Background:

Focal nodular hyperplasia (FNH) is a benign hepatic lesion that is rare in children. The aim of the present study was to review the clinical features of children with FNH and our institution's experience in the management of this rare disease.

Methods:

A review of the medical records of children diagnosed as having FNH between 1999 and 2013 at West China Hospital of Sichuan University was undertaken.

Results:

Seventy‐nine patients with FNH were identified: 68 patients without a history of malignancy and 11 patients with a history of malignancy. Thirty‐seven (46.8%) patients were symptomatic at presentation. Patients with a history of malignancy had smaller FNH lesions and were less likely to have a central scar in FNH than do patients without a history of malignancy. Forty‐seven patients underwent liver resection because of concern for malignancy, symptoms, and/or large lesions. Three patients were treated by embolization because of compression of the adjacent organs. There was no operative death or severe postoperative complications. Fourteen patients underwent liver biopsy to rule out malignant masses. The remaining 15 patients were managed expectantly with imaging surveillance. On follow‐up, 2 patients for whom observation was initially recommended eventually required resection because of a mass effect.

Conclusions:

The clinical features of pediatric FNH are variable and can be nonspecific. Our data emphasize the therapeutic approach that active management is indicated in symptomatic or progressive FNH and in children with diagnostic difficulties, whereas observation management is recommended in asymptomatic children with a definitive diagnosis.