bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhanced piezoelectric wind energy harvesting based on a buckled beam
Authors: Zhang Jiantao , Zhang Jia , Shu Chang , Fang Zhou
Published: May 2017

In order to improve the wind energy conversion efficiency, this study entails a concept utilizing the buckling behavior of a buckled beam to induce large amplitude oscillations in a PVDF beam harvester. Specifically, when the buckled beam subjected to the buckling load is in an unstable condition, the wind load can trigger the drastic vibration of the PVDF beam harvester. Experimental results demonstrate that the output performances of the proposed harvester are improved dramatically compared with a traditional cantilever beam harvester.
Characterization of an induced pressure pumping force for microfluidics
Authors: Jiang Hai , Fan Na , Peng Bei , Weng Xuan
Published: May 2017

The electro-osmotic pumping and pressure-driven manipulation of fluids are considered as the most common strategies in microfluidic devices. However, both of them exhibit major disadvantages such as hard integration and high reagent consumption, and they are destructive methods for detection and photo bleaching. In this paper, an electric field-effect flow control approach, combining the electro-osmotic pumping force and the pressure-driven pumping force, was developed to generate the induced pressure-driven flow in a T-shaped microfluidic chip. Electro-osmotic flow between the T-intersection and two reservoirs was demonstrated, and it provided a stable, continuous, and electric field-free flow in the section of the microchannel without the electrodes. The velocity of the induced pressure-driven flow was linearly proportional to the applied voltages. Both numerical and experimental investigations were conducted to prove the concept, and the experimental results showed good agreement with the numerical simulations. In comparison to other induced pressure pumping methods, this approach can induce a high and controllable pressure drop in the electric field-free segment, subsequently causing an induced pressure-driven flow for transporting particles or biological cells. In addition, the generation of bubbles and the blocking of the microchannel are avoided.
Concentration dependent carriers dynamics in CsPbBr3 perovskite nanocrystals film with transient grating
Authors: Wang Yinghui , Wang Yanting , Dev Verma Sachin , Tan Mingrui , Liu Qinghui , Yuan Qilin , Sui Ning , Kang Zhihui , Zhou Qiang , Zhang Han-Zhuang
Published: May 2017

The concentration dependence of the carrier dynamics is a key parameter to describe the photo-physical properties of semiconductor films. Here, we investigate the carrier dynamics in the CsPbBr3 perovskite nanocrystal film by employing the transient grating (TG) technique with continuous bias light. The concentration of initial carriers is determined by the average number of photons per nanocrystals induced by pump light (⟨N⟩). The multi-body interaction would appear and accelerate the TG dynamics with ⟨N⟩. When ⟨N⟩ is more than 3.0, the TG dynamics slightly changes, which implies that the Auger recombination would be the highest order multi-body interaction in carrier recombination dynamics. The concentration of non-equilibrium carriers in the film is controlled by the average number of photons per nanocrystals excited by continuous bias light (⟨nne⟩). Increasing  ⟨nne⟩ would improve the trapping-detrapping process by filling the trapping state, which would accelerate the carrier diffusion and add the complexity of the mono-molecular recombination mechanism. The results should be useful to further understand the mechanism of carrier dynamics in the CsPbBr3 perovskite nanocrystal film and of great importance for the operation of the corresponding optoelectronic devices.
Demonstration of a mid-wavelength infrared narrowband thermal emitter based on GaN/AlGaN quantum wells and a photonic crystal
Authors: Kang Dongyeon Daniel , Inoue Takuya , Asano Takashi , Noda Susumu
Published: May 2017

We experimentally demonstrate a thermal emitter with a narrow-bandwidth and low background emission, operating in the mid-wavelength infrared (MWIR) range, based on a combination of intersubband transitions in GaN/AlGaN multiple quantum wells and optical resonance in a photonic crystal slab. The fabricated device exhibits single-peak narrowband thermal emission with a Q factor of 93 at a wavelength of 4.0 μm. Stable operation at high temperatures over 700 °C has been demonstrated owing to the good thermal stability of GaN/AlGaN, which enables the generation of strong peak emission intensity as high as 93 mW/μm/sr/cm2. Such a narrow-band and low-background emitter in the MWIR range has been difficult to realize by metal or heavily doped semiconductor-based emitters due to the broadband emission characteristics of the materials and by GaAs/AlGaAs-based emitters due to the thermal instability of the materials. Our device can be applied to various MWIR applications including CO2 and NOx gas sensing systems.
Polybenzofulvenes-based blends with benzothiadiazole and perylene diimide derivatives emitting from yellow to the deep-red by resonant energy transfer processes
Authors: Villafiorita-Monteleone F. , Kozma E. , Pasini M. , Paolino M. , Cappelli A. , Bongiovanni G. , Mura A. , Botta C.
Published: May 2017

The ability of a π-stacked polybenzofulvene derivative to self-assemble with emissive dyes in supramolecular organizations that reduce unwanted microaggregation processes is demonstrated by a study of the photophysical properties of its blends with benzothiadiazole and two perylenediimide derivatives. Films displaying efficient emissions with quantum yields of 0.85 in the yellow, 0.54 in the red, and 0.39 in the deep-red regions are obtained thanks to combined homo- and hetero-resonant energy transfer processes from the polymer excimer-like π-stacked chromophores to the emitting dyes.
Characterizations of nonlinear optical properties on GaN crystals in polar, nonpolar, and semipolar orientations
Authors: Chen Hong , Huang Xuanqi , Fu Houqiang , Lu Zhijian , Zhang Xiaodong , Montes Jossue A. , Zhao Yuji
Published: May 2017

We report the basic nonlinear optical properties, namely, two-photon absorption coefficient (β), three-photon absorption coefficient (γ), and Kerr nonlinear refractive index (nkerr), of GaN crystals in polar c-plane, nonpolar m-plane, and semipolar (2021¯) plane orientations. A typical Z-scan technique was used for the measurement with a femtosecond Ti:S laser from wavelengths of 724 nm to 840 nm. For the two-photon absorption coefficient (β), similar values were obtained for polar, nonpolar, and semipolar samples, which are characterized to be ∼0.90 cm/GW at 724 nm and ∼0.65 cm/GW at 730 nm for all the three samples. For the Kerr nonlinear refractive index (nkerr), self-focusing features were observed in this work, which is different from previous reports where self-defocusing features were observed on GaN in the visible and near-UV spectral regions. At 724 nm, nkerr was measured to be ∼2.5 0×10−14 cm2/W for all three samples. Three-photon absorption coefficients (γ) were also determined, which were found to be consistent with previous reports. This study provides valuable information on the basic nonlinear optical properties of III-nitride semiconductors, which are vital for a wide range of applications such as integrated photonics and quantum photonics.
Dielectric elastomer fingers for versatile grasping and nimble pinching
Authors: Lau Gih-Keong , Heng Kim-Rui , Ahmed Anansa S. , Shrestha Milan
Published: May 2017

Boneless soft robotic fingers cannot apply concentrated forces to pinch a delicate object. This letter reports a three-dimensional design of dielectric elastomer fingers with higher flexural stiffness and close to 90° voltage-controllable bending for object gripping and pinching. It makes use of tension arch flexures to elevate a pre-stretched dielectric elastomer actuator (DEA) into a roof shape and thus magnifies the tension-induced moment, 40 times higher than a flat DEA does, to bend a stiff base frame. Such fingers make normally close-grippers to lift a payload 8–9 times their weight. They also make normally open grippers that pinch a highly deformable raw egg yolk.
Selective coherent perfect absorption of subradiant mode in ultrathin bi-layer metamaterials via antisymmetric excitation
Authors: Tan Wei , Zhang Caihong , Li Chun , Zhou Xiaoying , Jia Xiaoqing , Feng Zheng , Su Juan , Jin Biaobing
Published: May 2017

We demonstrate that the subradiant mode in ultrathin bi-layer metamaterials can be exclusively excited under two-antisymmetric-beam illumination (or equivalently, at a node of the standing wave field), while the superradiant mode is fully suppressed due to their different mode symmetry. Coherent perfect absorption (CPA) with the Lorentzian lineshape can be achieved corresponding to the subradiant mode. A theoretical model is established to distinguish the different behaviors of these two modes and to elucidate the CPA condition. Terahertz ultrathin bi-layer metamaterials on flexible polyimide substrates are fabricated and tested, exhibiting excellent agreement with theoretical predictions. This work provides physical insight into how to selectively excite the antisymmetric subradiant mode via coherence incidence.
Lactational challenges in transition dairy cows
Authors: Bruckmaier R. M. , Gross J. J.
Published: May 2017

Lactation evolved to be the core functional system of providing maternal care in mammalian species. The mammary gland provides an ideally composed nutrient source for the newborn. In addition, colostrum provides passive immunisation after birth, and each suckling process supports the establishment and maintenance of a close mother–offspring bonding. The importance of lactation for the survival of the offspring is represented by a high metabolic priority of the mammary gland within the organism of the lactating animal. Therefore, animal breeding for high milk production has been quite successful, and modern breeding methods have allowed an enormous increase in the performance within only few generations of cows. Mainly in early lactation, most of the available nutrients are directed to the mammary gland, both those from feed, and those mobilised from body tissue. Therefore, milk production can be maintained at a high level despite a negative energy balance. However, the high metabolic load and mobilisation of body tissue requires adequate endocrine and metabolic regulation, which can be successful or less successful in individual animals, i.e. the dairy cow population consists of both metabolically robust and metabolically vulnerable dairy cows. While robust animals adapt adequately, vulnerable cows show often high plasma concentrations of non-esterified fatty acids and β-hydroxybutyrate, and are prone to various production-related diseases. In pasture- or forage-based feeding systems, an additional challenge is a limited availability of nutrients for milk production. Forage feeding without complementary concentrate leads to enormous metabolic disorders in high-yielding cows, but is tolerated in dairy cows with a moderate genetic-performance level.
Soil physical properties in relation to maize (Zea mays) yield after tillage and application of organic and inorganic fertilisers in Abeokuta, southwestern Nigeria
Authors: Busari M. A.
Published: May 2017

Moderation of soil disturbance following tillage operations using external inputs, particularly organic manures, is becoming an important aspect of soil tillage management. This study examined the effects of tillage, poultry manure (PM) and NPK fertiliser on soil physical properties and their relationship with maize yield. The experiment was a split-split-plot design with three replications. Tillage (zero tillage (ZT), minimum tillage (MT) and conventional tillage (CT)) was the main plot, the subplot contained four NPK fertiliser treatments (0, 90, 120 and 150kg N ha–1), and the sub-subplots comprised three PM treatments (0, 10 and 20 Mg ha–1). The soil texture was gravelly loamy sand. Soil bulk density (BD), total porosity (Pt), clay dispersion ratio (CDR) and saturated hydraulic conductivity (Ks) were evaluated. Samples for BD and Ks were collected from the soil surface using stainless cylindrical soil core (5cm in diameter and 5cm in height), whereas samples for CDR determination were collected at 0–20cm soil depth. Compared with the ZT, significantly lower BD was obtained under CT plots at 4 weeks after planting (WAP), which increased at 12 WAP possibly due to slaking and collapse of soil particles by raindrops. Application of PM resulted in significantly lower BD than the unmanured plots. There was a significant interaction effect among tillage, PM and NPK fertiliser on soil physical properties. In plots treated with combined 20 Mg ha–1 PM (PM20) and 150kg N ha–1, the soil Pt of 55.6% and 57.2% obtained under CT and MT respectively at the end of the second year were significantly higher than those of the control plots (48.5% (CT) and 47.5% (MT)). In general, combined application of NPK and PM did not result in significant differences in CDR and Ks under MT and CT but the higher rate of PM (PM20) and NPK fertiliser under ZT significantly raised the CDR and reduced Ks by 20–43% in 2008 and 23–45% in 2009 relative to the unmanured plots. This implies disaggregation (higher CDR), which possibly resulted in creation of water-repellent properties causing lower Ks. Although Ks and CDR showed no significant relation with grain yield, BD was significantly related with maize grain yield with MT tending to produce ~23% and 20% higher maize grain yield than ZT and CT respectively under a typical arable surface soil BD. Therefore, integrated use of PM and NPK fertiliser is beneficial to soil physical qualities, especially under tillage management, but high quantities of PM should be avoided under ZT soil.
Vimentin fibers orient traction stress
Authors: Costigliola Nancy , Ding Liya , Burckhardt Christoph J. , Han Sangyoon J. , Gutierrez Edgar , Mota Andressa , Groisman Alex , Mitchison Timothy J. , Danuser Gaudenz
Published: May 2017

Significance

Vimentin is a marker for the epithelial-to-mesenchymal transition, which is thought to lead to cancer metastasis. Without vimentin, planar cells exhibit polarity defects and cannot migrate as single cells. The mechanisms by which vimentin influences cell migration remain mostly unknown, however. Generally, intermediate filaments regulate the mechanical integrity of cells and tissues; thus, we hypothesized that vimentin could be involved in supporting the directionally aligned force transmission required for single-cell migration. We have developed imaging and analysis methods to probe the role of vimentin in mesenchymal cell migration that will have broad utility in intermediate filament research. In summary, our results demonstrate that vimentin governs the alignment of the cell traction forces needed for directed single-cell mesenchymal migration.
Elucidating interplay of speed and accuracy in biological error correction
Authors: Banerjee Kinshuk , Kolomeisky Anatoly B. , Igoshin Oleg A.
Published: May 2017

Significance

Biological processes are unique in showing a remarkable level of accuracy in discriminating between similar molecules. This characteristic is attributed to an error-correcting mechanism known as kinetic proofreading. It is widely believed that the enhancement of the accuracy in biological processes always slows them down. By analyzing the fundamental processes of DNA replication and protein translation, we established that these systems maximize speed rather than accuracy with additional energetic constraints. Our theoretical study further indicates that both speed and accuracy can be enhanced in certain parameter regimes. The resulting findings provide a microscopic picture of how complex biological processes can be accomplished so quickly with minimal errors.
High-density lipoprotein receptor SCARB1 is required for carotenoid coloration in birds
Authors: Toomey Matthew B. , Lopes Ricardo J. , Araújo Pedro M. , Johnson James D. , Gazda Małgorzata A. , Afonso Sandra , Mota Paulo G. , Koch Rebecca E. , Hill Geoffrey E. , Corbo Joseph C. , Carneiro Miguel
Published: May 2017

Significance

The yellow, orange, and red colors of birds are produced through the deposition of carotenoid pigments into feathers and skin, and often function as signals in aggressive interactions and mate choice. These colors are hypothesized to communicate information about individual quality because their expression is linked to vital cellular processes through the mechanisms of carotenoid metabolism. To elucidate these mechanisms, we carried out genomic and biochemical analyses of the white recessive canary breed, which carries a heritable defect in carotenoid uptake. We identified a mutation in theSCARB1gene in this breed that disrupts carotenoid transport function. Our study implicates SCARB1 as a key mediator of carotenoid-based coloration and suggests a link between carotenoid coloration and lipid metabolism.
Revealing the frictional transition in shear-thickening suspensions
Authors: Clavaud Cécile , Bérut Antoine , Metzger Bloen , Forterre Yoël
Published: May 2017

Significance

The sudden and severe increase in the viscosity of certain suspensions above an onset stress is one of the most spectacular phenomena observed in complex fluids. This shear thickening, which has major implications for industry, is a long-standing puzzle in soft-matter physics. Recently, a frictional transition was conjectured to cause this phenomenon. Using experimental concepts from granular physics, we provide direct evidence that such suspensions are frictionless under low confining pressure, which is key to understanding their shear-thickening behavior.
Structural variants caused byAluinsertions are associated with risks for many human diseases
Authors: Payer Lindsay M. , Steranka Jared P. , Yang Wan Rou , Kryatova Maria , Medabalimi Sibyl , Ardeljan Daniel , Liu Chunhong , Boeke Jef D. , Avramopoulos Dimitri , Burns Kathleen H.
Published: May 2017

Significance

Repetitive sequences comprise a large portion of the genome and are often thought of as “junk DNA.” They are a significant source of genetic variation, particularlyAluelements. Their functional consequence is frequently dismissed. Here, we test the hypothesis thatAlupolymorphisms contribute to phenotypic differences between individuals. We identified an enrichment ofAlupolymorphisms in regions of the genome associated with human disease risk. Further, we find 44 instances where the trait-associated SNP is a surrogate for presence or absence of anAluinsertion. This finding indicates that theAlumay be the variant effecting disease risk, an intriguing possibility given its size and regulatory potential. This work emphasizes the importance of considering repeat polymorphisms in functional variant analysis.
Anglicisms and word axiology in homosexual language
Authors: Crespo-Fernández Eliecer , Luján-García Carmen
Published: May 2017

Among those areas linked to the forbidden, homosexuality has traditionally met one of the strongest interdictions. Given the taboo nature of homosexuality, it is our purpose in this paper to gain an insight into the axiological values that anglicisms present in the Spanish homosexual vocabulary. The analysis of the different types of anglicisms in a sample of 253 English borrowings reveals that pure anglicisms (including clippings and initialisms) are the most frequently used, followed by pseudoanglicisms. Calques, hybrids and adapted anglicisms are used less often to refer to homosexuality. The research carried out reveals that anglicized units perform different X-phemistic functions in homosexual discourse: not only that of softening or avoiding the use of a taboo term in Spanish but also displaying in-group solidarity or referring to homosexuality disparagingly. Homosexual-related anglicisms promote innovative uses of the Spanish language and provide evidence of a special kind of language used by homosexuals.
Análisis de las líneas de investigación y actuación en la enseñanza y el aprendizaje del lenguaje oral en contexto escolar
Authors: Gràcia Marta , Galván-Bovaira Maria José , Sánchez-Cano Manel
Published: May 2017

En la Educación obligatoria enseñar y aprender la competencia lingüística en sus ámbitos de hablar y escuchar para comunicarse y construir conocimiento, requiere de acciones educativas específicas. Este trabajo revisa descriptivamente las perspectivas de estudio que abordan este tema. Hemos consultado diversas bases de datos para seleccionar los autores relevantes e identificar las estrategias y actividades que cada perspectiva prioriza para enseñar y aprender el uso del lenguaje oral en el aula. Las perspectivas analizadas son siete, incluyendo la didáctica de la lengua, la interacción comunicativa en el aula, o el TIL (Tratamiento Integrado de Lenguas), entre otras. Las estrategias de enseñanza son diversas y las actividades más frecuentes son las exposiciones orales y los debates. Los resultados aportan una visión de conjunto y manifiestan que la enseñanza y el aprendizaje del uso del lenguaje oral requieren una programación y definición de objetivos de aprendizaje sistemática.
Conceptual complexes in cognitive modeling
Authors: Ruiz de Mendoza Ibáñez Francisco José
Published: May 2017

The present paper goes beyond previous treatments of cognitive models, especially conceptual metaphor and metonymy, by drawing on linguistic evidence. It introduces needed refinements into previous meaning construction accounts by investigating the activity ofconceptual complexes, i.e., combinations of cognitive models whose existence can be detected from a careful examination of the meaning effects of some linguistic expressions. This improvement endows the linguist with a more powerful set of analytical tools capable of dealing with a broader range of phenomena than previous theories. The paper first exploresmetaphoricandmetonymic complexes, and their meaning effects. Then, it addresses the metonymic exploitation offrame complexesandimage-schematic complexes. The resulting analytical apparatus proves applicable to the study offictive motionandimage-schema transformations, which have so far been addressed in Cognitive Linguistics without making explicit any relation between them or with other phenomena. We give evidence that these two phenomena can be dealt with as specific cases of metonymic domain expansion and domain reduction respectively. This means that fictive motion and image-schema transformations can be fully integrated into an encompassing account of cognitive modeling based on the activity of single or combined cognitive operations on basic or complex cognitive models.
Procesamiento temporal auditivo de estímulos lingüísticos y no lingüísticos en niños con dificultades en lectura
Authors: Muñetón Ayala Mercedes Amparo , Rosario Ortiz María del , Estévez Monzó Adelina , Vásquez Claudia
Published: May 2017

Este estudio examina si niños con dificultades lectoras presentan déficit en el procesamiento temporal de estímulos auditivos, y si este déficit es específico al procesamiento del lenguaje. El diseño usa el mismo paradigma para evaluar estímulos lingüísticos y no-lingüísticos y se controla la complejidad de ambos tipos de estímulos. Se evaluaron 10 niños sin dificultades en la lectura y 11 niños con dificultades en lectura emparejados en edad (8–9 años) en tareas de juicio de orden temporal. La tarea consiste en determinar el orden en el que perciben las silabas /pa/ – /ba/, las cuales difieren en sonoridad, y dos tonos que difieren en la frecuencia (260 – 470 Hz). Los resultados muestran que los problemas en el procesamiento temporal de los niños con dificultades en la lectura son específicos al procesamiento de estímulos lingüísticos. La discusión se centra en el papel del procesamiento temporal del lenguaje en la lectura.
Why are Suicide Rates Climbing after Years of Decline?
Authors: Valko Nancy
Published: May 2017

There is evidence that the increasing rates of suicide can be linked to the legalization of physician-assisted suicide. Factors such as suicide contagion and the increasing positive media reporting on such suicides are also relevant and have led to different standards of treatment for suicidal people who claim the right to have their suicides medically assisted.
Metal-organic frameworks based materials for photocatalytic CO2 reduction
Authors: Crake Angus
Published: May 2017

Photocatalytic conversion of CO2 to valuable chemicals by solar irradiation is a hugely attractive process due to its potential to offset both the energy and economic penalties of CO2 capture and sequestration. Metal-organic frameworks (MOFs) have recently been explored as photocatalysts for this processing owing to their promising photochemical and textural properties. Papers to date are collated and reviewed to highlight advances made in MOF photocatalysts through novel synthesis and analytical methods. These are compared with key metrics highlighting the range of materials and methods used to show the diversity and novelty of this emerging field. Knowledge gaps were noted in order to propose potential routes for further improvements in catalyst and reactor design.

This review was chosen as a runner up of the 2017 Materials Literature Review Prize of the Institute of Materials, Minerals and Mining, run by the Editorial Board of MST. Sponsorship of the prize by TWI Ltd is gratefully acknowledged
Effects of the TiC and sintering process on the TiC-steel composite
Authors: Wang Zhi , He Xinbo , Lin Tao , Guo You , Shao Huiping , Qu Xuanhui
Published: May 2017

In this paper, the composite of low alloy steel reinforced with TiC particles was prepared by conventional powder metallurgy process. The effects of the combined carbon content of TiC powder, sintering temperature and heating rate on the composite were studied. The results showed that the selected TiC powder has a combined carbon content of 17.91 wt-% and the optimal sintering process is heating from 600 to 1440°C at a rate of 1°C min−1 and holding for 1 h at 1440°C. The composite after heat treatment has excellent mechanical properties with density of 6.45 g cm−3, hardness of 68–69 HRC and TRS of 1763 MPa, respectively, and will be used as wear-resistant parts, assembly fixtures, moulds, etc.
Effect of strain rate on fracture of U-5.5Nb alloy
Authors: Chen Dong , Chen Xianglin , Ma Rong , Tang Qingfu , Su Bin , Wang Zhenhong , Zhang Xinjian , Meng Daqiao
Published: May 2017

The microstructure and tensile properties of an aged U-5.5 wt-% Nb alloy have been experimentally investigated with the aim of obtaining the influence of strain rates on fracture behaviour. The result shows that strain to failure is sensitive to strain rate and decreases with an increase in the strain rate. Fracture surface analysis indicates that the alloy exhibits a typical ductile fracture. Two types of carbides (niobium carbide and uranium carbide), mainly distributed at the grain boundary, are confirmed, which participate in the process of fracture and are involved in different void nucleation mechanisms during the final ductility fracture. Namely, niobium carbide tends to generate voids by debonding with the matrix, while uranium carbide is more likely to experience cracking.
Ablation resistance of carbides-coated C/C composites
Authors: Li Hejun , Wang Yongjie , Fu Qiangang
Published: May 2017

To improve the ablation resistance of C/C composites under oxyacetylene flame, SiC, TaC and HfC coatings were fabricated on composites surface. Ablation properties of coatings were detected and the ablation mechanism was discussed in the paper as well. The centre region of SiC and TaC coatings has failed during ablation and exhibited high ablative rates; it attributed to so high ablation temperature, which was much higher melting point of their oxides (Ta2O5 and SiO2). HfC coating exhibited lowest ablative rates. The reason is that the ablation temperature was just between sinter point and melting temperature of HfO2, the oxides could behave as the thermal barrier coating during ablation and provide efficient protection for C/C composites. It can be indicated that the carbide coating provides best ablation protection between the Tammann temperature and melting point of their oxides.
Multilevel regulation of an α-arrestin by glucose depletion controls hexose transporter endocytosis
Authors: Hovsepian Junie , Defenouillère Quentin , Albanèse Véronique , Váchová Libuše , Garcia Camille , Palková Zdena , Léon Sébastien
Published: May 2017

Nutrient availability controls the landscape of nutrient transporters present at the plasma membrane, notably by regulating their ubiquitylation and subsequent endocytosis. In yeast, this involves the Nedd4 ubiquitin ligase Rsp5 and arrestin-related trafficking adaptors (ARTs). ARTs are targeted by signaling pathways and warrant that cargo ubiquitylation and endocytosis appropriately respond to nutritional inputs. Here, we show that glucose deprivation regulates the ART protein Csr2/Art8 at multiple levels to trigger high-affinity glucose transporter endocytosis. Csr2 is transcriptionally induced in these conditions through the AMPK orthologue Snf1 and downstream transcriptional repressors. Upon synthesis, Csr2 becomes activated by ubiquitylation. In contrast, glucose replenishment induces CSR2 transcriptional shutdown and switches Csr2 to an inactive, deubiquitylated form. This glucose-induced deubiquitylation of Csr2 correlates with its phospho-dependent association with 14-3-3 proteins and involves protein kinase A. Thus, two glucose signaling pathways converge onto Csr2 to regulate hexose transporter endocytosis by glucose availability. These data illustrate novel mechanisms by which nutrients modulate ART activity and endocytosis.
Bipotent progenitors as embryonic origin of retinal stem cells
Authors: Tang Xia , Gao Jianan , Jia Xinling , Zhao Wencao , Zhang Yijie , Pan Weijun , He Jie
Published: May 2017

In lower vertebrates, retinal stem cells (RSCs) capable of producing all retinal cell types are a resource for retinal tissue growth throughout life. However, the embryonic origin of RSCs remains largely elusive. Using a Zebrabow-based clonal analysis, we characterized the RSC niche in the ciliary marginal zone of zebrafish retina and illustrate that blood vessels associated with RSCs are required for the maintenance of actively proliferating RSCs. Full lineage analysis of RSC progenitors reveals lineage patterns of RSC production. Moreover, in vivo lineage analysis demonstrates that these RSC progenitors are the direct descendants of a set of bipotent progenitors in the medial epithelial layer of developing optic vesicles, suggesting the involvement of the mixed-lineage states in the RSC lineage specification.
A voltage-dependent K+ channel in the lysosome is required for refilling lysosomal Ca2+ stores
Authors: Wang Wuyang , Zhang Xiaoli , Gao Qiong , Lawas Maria , Yu Lu , Cheng Xiping , Gu Mingxue , Sahoo Nirakar , Li Xinran , Li Ping , Ireland Stephen , Meredith Andrea , Xu Haoxing
Published: May 2017

The resting membrane potential (Δψ) of the cell is negative on the cytosolic side and determined primarily by the plasma membrane’s selective permeability to K+. We show that lysosomal Δψ is set by lysosomal membrane permeabilities to Na+ and H+, but not K+, and is positive on the cytosolic side. An increase in juxta-lysosomal Ca2+ rapidly reversed lysosomal Δψ by activating a large voltage-dependent and K+-selective conductance (LysoKVCa). LysoKVCa is encoded molecularly by SLO1 proteins known for forming plasma membrane BK channels. Opening of single LysoKVCa channels is sufficient to cause the rapid, striking changes in lysosomal Δψ. Lysosomal Ca2+ stores may be refilled from endoplasmic reticulum (ER) Ca2+ via ER–lysosome membrane contact sites. We propose that LysoKVCa serves as the perilysosomal Ca2+ effector to prime lysosomes for the refilling process. Consistently, genetic ablation or pharmacological inhibition of LysoKVCa, or abolition of its Ca2+ sensitivity, blocks refilling and maintenance of lysosomal Ca2+ stores, resulting in lysosomal cholesterol accumulation and a lysosome storage phenotype.
Complex perspective for the projective heat map acting on pentagons
Authors: Kaschner Scott , Roeder Roland
Published: May 2017

We place Schwartz’s work on the real dynamics of the projective heat map

H
H

into the complex perspective by computing its first dynamical degree and gleaning some corollaries about the dynamics of

H
H

.
A new proof of scattering below the ground state for the 3d radial focusing cubic NLS
Authors: Dodson Benjamin , Murphy Jason
Published: May 2017

We revisit the scattering result of Holmer and Roudenko (2008) on the radial focusing cubic NLS in three space dimensions. Using the radial Sobolev embedding and a virial/Morawetz estimate, we give a simple proof of scattering below the ground state that avoids the use of concentration compactness.
Aberrant caveolin-1–mediated Smad signaling and proliferation identified by analysis of adenine 474 deletion mutation (c.474delA) in patient fibroblasts: a new perspective on the mechanism of pulmonary hypertension
Authors: Marsboom Glenn , Chen Zhenlong , Yuan Yang , Zhang Yanmin , Tiruppathi Chinnaswamy , Loyd James E. , Austin Eric D. , Machado Roberto F. , Minshall Richard D. , Rehman Jalees , Malik Asrar B.
Published: May 2017

A heterozygous caveolin-1 c.474delA mutation has been identified in a family with heritable pulmonary arterial hypertension (PAH). This frameshift mutation leads to a caveolin-1 protein that contains all known functional domains but has a change in only the final 20 amino acids of the C-terminus. Here we studied how this mutation alters caveolin-1 function, using patient-derived fibroblasts. Transmission electron microscopy showed that fibroblasts carrying the c.474delA mutation form typical caveolae. Expression of mutated caveolin-1 in caveolin-1–null mouse fibroblasts failed to induce formation of caveolae due to retention of the mutated protein in the endoplasmic reticulum. However, coexpression of wild-type caveolin-1 with mutated caveolin-1 restored the ability to form caveolae. Importantly, fibroblasts carrying the mutation showed twofold increase in proliferation rate associated with hyperphosphorylation of Smad1/5/8. This mutation impaired the antiproliferative function of caveolin-1. Inhibition of type I TGFβ receptors ALK1/2/3/6 responsible for phosphorylation of Smad1/5/8 reduced the hyperproliferation seen in c.474delA fibroblasts. These results demonstrate the critical role of the final 20 amino acids of caveolin-1 in modulating fibroblast proliferation by dampening Smad signaling and suggest that augmented Smad signaling and fibroblast hyperproliferation are contributing factors in the pathogenesis of PAH in patients with caveolin-1 c.474delA mutation.
SinCHet: a MATLAB toolbox for single cell heterogeneity analysis in cancer
Authors: Li Jiannong , Smalley Inna , Schell Michael J , Smalley Keiran S M , Chen Y Ann
Published: May 2017

Single-cell technologies allow characterization of transcriptomes and epigenomes for individual cells under different conditions and provide unprecedented resolution for researchers to investigate cellular heterogeneity in cancer. The SinCHet (Single Cell Heterogeneity) toolbox is developed in MATLAB and has a graphical user interface (GUI) for visualization and user interaction. It analyzes both continuous (e.g. mRNA expression) and binary omics data (e.g. discretized methylation data). The toolbox does not only quantify cellular heterogeneity using Shannon Profile (SP) at different clonal resolutions but also detects heterogeneity differences using a D statistic between two populations. It is defined as the area under the Profile of Shannon Difference (PSD). This flexible tool provides a default clonal resolution using the change point of PSD detected by multivariate adaptive regression splines model; it also allows user-defined clonal resolutions for further investigation. This tool provides insights into emerging or disappearing clones between conditions, and enables the prioritization of biomarkers for follow-up experiments based on heterogeneity or marker differences between and/or within cell populations.

Availability and implementation

The SinCHet software is freely available for non-profit academic use. The source code, example datasets, and the compiled package are available at http://labpages2.moffitt.org/chen/software/.

Supplementary information

Supplementary data are available at Bioinformatics online.
The use of Twitter to facilitate sharing of clinical expertise in urology
Authors: Sternberg Kevan M , Loeb Stacy L , Canes David , Donnelly Laura , Tsai Mitchell H
Published: May 2017

The use of social media in the urologic community is common and increasing. Although the potential benefits of platforms like Twitter have been described in the literature, the use of social media in the clinical context of Urology has not been explored.

In this case report, we describe how we used Twitter to share ideas about the clinical management of a complex urologic patient. By posting a clinical scenario, a timely discussion was generated with global participation and expert suggestions. This knowledge was applied to the surgical management of a patient with positive clinical outcomes.

The ability of Twitter to facilitate rapid communication with a wide network of contributors makes it a potentially useful tool for clinical decision making. Care must be taken to ensure patient confidentiality and caution used appropriately when evaluating the sources and content of the clinical information shared.
Magnetic field formation in the Milky Way like disc galaxies of the Auriga project
Authors: Pakmor Rüdiger , Gómez Facundo A. , Grand Robert J. J. , Marinacci Federico , Simpson Christine M. , Springel Volker , Campbell David J. R. , Frenk Carlos S. , Guillet Thomas , Pfrommer Christoph , White Simon D. M.
Published: May 2017

The magnetic fields observed in the Milky Way and nearby galaxies appear to be in equipartition with the turbulent, thermal and cosmic ray energy densities, and hence are expected to be dynamically important. However, the origin of these strong magnetic fields is still unclear, and most previous attempts to simulate galaxy formation from cosmological initial conditions have ignored them altogether. Here, we analyse the magnetic fields predicted by the simulations of the Auriga Project, a set of 30 high-resolution cosmological zoom simulations of Milky Way like galaxies, carried out with a moving-mesh magnetohydrodynamics code and a detailed galaxy formation physics model. We find that the magnetic fields grow exponentially at early times owing to a small-scale dynamo with an e-folding time of roughly 100 Myr in the centre of haloes until saturation occurs around z = 2–3, when the magnetic energy density reaches about 10 per cent of the turbulent energy density with a typical strength of $10\text{--}50\,\rm {\mu G}$. In the galactic centres, the ratio between magnetic and turbulent energies remains nearly constant until z = 0. At larger radii, differential rotation in the discs leads to linear amplification that typically saturates around z = 0.5–0. The final radial and vertical variations of the magnetic field strength can be well described by two joint exponential profiles, and are in good agreement with observational constraints. Overall, the magnetic fields have only little effect on the global evolution of the galaxies as it takes too long to reach equipartition. We also demonstrate that our results are well converged with numerical resolution.
Development and Evaluation of an Implementation Strategy for Collecting Data in a National Registry and the Use of Patient-Reported Outcome Measures in Physical Therapist Practices: Quality Improvement Study
Authors: Meerhoff Guus A. , van Dulmen Simone A. , Maas Marjo J.M. , Heijblom Karin , Nijhuis-van der Sanden Maria W.G. , Van der Wees Philip J.
Published: May 2017

Background. In 2013, the Royal Dutch Society for Physical Therapy launched the program “Quality in Motion.” This program aims to collect data from electronic health record systems in a registry that is fed back to physical therapists, facilitating quality improvement.

Purpose. The purpose of this study was to describe the development of an implementation strategy for the program and to evaluate the feasibility of building a registry and implementing patient-reported outcome measures (PROMs) in physical therapist practices.

Methods. A stepwise approach using mixed methods was established in 3 consecutive pilots with 355 physical therapists from 66 practices. Interim results were evaluated using quantitative data from a self-assessment questionnaire and the registry and qualitative data from 21 semistructured interviews with physical therapists. Descriptive statistics and McNemar's symmetry chi-squared test were used to summarize the feasibility of implementing PROMs.

Results. PROMs were selected for the 5 most prevalent musculoskeletal conditions in Dutch physical therapist practices. A core component of the implementation strategy was the introduction of knowledge brokers to support physical therapists in establishing the routine use of PROMs in clinical practice and to assist in executing peer assessment workshops. In February 2013, 30.3% of the physical therapist practices delivered 4.4 completed treatment episodes per physical therapist to the registry; this increased to 92.4% in November 2014, delivering 54.1 completed patient episodes per physical therapist. Pre- and posttreatment PROM use increased from 12.2% to 39.5%.

Limitations. It is unclear if the participating physical therapists reflect a representative sample of Dutch therapists.

Conclusion. Building a registry and implementing PROMs in physical therapist practices are feasible. The routine use of PROMs needs to increase to ensure valid feedback of outcomes. Using knowledge brokers is promising for implementing the program via peer assessment workshops.
Evaluating the Impact of Educational Interventions on Patients and Communities: A Conceptual Framework
Authors: Bzowyckyj Andrew S. , Dow Alan , Knab Mary S.
Published: May 2017

Health professions education programs can have direct effects on patients and communities as well as on learners. However, few studies have examined the patient and community outcomes of educational interventions. To better integrate education and health care delivery, educators and researchers would benefit from a unifying framework to guide the planning of educational interventions and evaluation of their impact on patients.

The authors of this Perspective mirrored approaches from Miller’s pyramid of educational assessment and Moore and colleagues’ framework for evaluating continuing professional development to propose a conceptual framework for evaluating the impact of educational interventions on patients and communities. This proposed framework, which complements these existing frameworks for evaluating the impact of educational interventions on learners, includes four levels: (1) interaction; (2) acceptability; (3) individual outcomes (i.e., knowledge, skills, activation, behaviors, and individual health indicators); and (4) population outcomes (i.e., community health indicators, capacity, and disparities). The authors describe measures and outcomes at each level and provide an example of the application of their new conceptual framework.

The authors encourage educators and researchers to use this conceptual framework to evaluate the impact of educational interventions on patients and to more clearly identify and define which educational interventions strengthen communities and enhance overall health outcomes.
Job Resources, Physician Work Engagement, and Patient Care Experience in an Academic Medical Setting
Authors: Scheepers Renée A. , Lases Lenny S.S. , Arah Onyebuchi A. , Heineman Maas Jan , Lombarts Kiki M.J.M.H.
Published: May 2017

Purpose

Physician work engagement is associated with better work performance and fewer medical errors; however, whether work-engaged physicians perform better from the patient perspective is unknown. Although availability of job resources (autonomy, colleague support, participation in decision making, opportunities for learning) bolster work engagement, this relationship is understudied among physicians. This study investigated associations of physician work engagement with patient care experience and job resources in an academic setting.

Method

The authors collected patient care experience evaluations, using nine validated items from the Dutch Consumer Quality index in two academic hospitals (April 2014 to April 2015). Physicians reported job resources and work engagement using, respectively, the validated Questionnaire on Experience and Evaluation of Work and the Utrecht Work Engagement Scale. The authors conducted multivariate adjusted mixed linear model and linear regression analyses.

Results

Of the 9,802 eligible patients and 238 eligible physicians, respectively, 4,573 (47%) and 185 (78%) participated. Physician work engagement was not associated with patient care experience (B = 0.01; 95% confidence interval [CI] = −0.02 to 0.03; P = .669). However, learning opportunities (B = 0.28; 95% CI = 0.05 to 0.52; P = .019) and autonomy (B = 0.31; 95% CI = 0.10 to 0.51; P = .004) were positively associated with work engagement.

Conclusions

Higher physician work engagement did not translate into better patient care experience. Patient experience may benefit from physicians who deliver stable quality under varying levels of work engagement. From the physicians’ perspective, autonomy and learning opportunities could safeguard their work engagement.
Evaluation of and Feedback for Academic Medicine Leaders: Developing and Implementing the Memorial Method
Authors: Rourke James , Bornstein Stephen , Vardy Cathy , Speed David , White Tyrone , Corbett Paula
Published: May 2017

Problem

Giving and receiving honest and helpful feedback for leadership development is a common challenge in all types of organizations but particularly in academic medicine.

Approach

At Memorial University of Newfoundland, in 2014, a consensus emerged to develop a new method for evaluating the leadership performance of the discipline chairs, dean, and vice dean, and to provide these leaders with the evaluation results to help them improve their performance. The leaders responsible for developing and implementing this method (called the Memorial Method) decided to use a survey to obtain faculty members’ perceptions about their leader’s performance. Beginning in October 2014, a portion of several regular meetings of the discipline chairs with the dean and vice dean was used to develop the survey, by first discussing the broad dimensions of leadership performance, then discussing these dimensions in more detail and drafting specific questions. The resulting survey included 44 quantitative questions addressing eight leadership dimensions. In March–April 2015, the survey was administered electronically to full-time faculty members on a confidential basis. The results were compiled and reported to each discipline chair and to the dean and vice dean.

Outcomes

In total, 144/249 faculty responded to the survey (response rate: 58%). For the various dimensions, individual chairs’ mean scores ranged from 2.82 to 4.70, and overall mean scores ranged from 3.57 to 4.24. Psychometric properties of the survey suggested it was both reliable and valid.

Next Steps

The survey will be repeated, this time with part-time as well as full-time faculty included.