bluuebunny/crossref_metadata_2025 huggingface dataset:
Graded morphology in bulk-heterojunction solar cells based on colloidal semiconductor nanostructures: Directed charge-separation and facile carrier transport
Authors: Dasgupta Uttiya , Pal Amlan J.
Published: August 2016

We introduce density gradient of p- and n-type compound semiconductor nanostructures in bulk-heterojunction (BHJ) solar cells. The graded BHJs (GBHJs) were formed with the p-type copper-zinc-tin-sulfide (Cu2ZnSnS4) nanoparticles and n-type Bi2S3 nanorods, both of which were based on nontoxic and earth-abundant elements and were grown at a moderate reaction temperature (180 °C). The concentration gradient of the nanostructures in the GBHJs provided a preferred directionality of nano-depletion regions for directed charge separation and also a controlled vertical segregation for ever-increasing carrier-transport pathways during the charge-extraction process. A comparison of solar cell characteristics having a bilayer, a BHJ, and a GBHJ structure is being presented. The performance of the thickness-optimized devices for highest efficiency shows that the GBHJ offered an improved short-circuit current as compared to the bilayer and the BHJ structures and a higher fill-factor as compared to the BHJ device. The overall energy conversion efficiency (η) of GBHJ exceeded that of the other two heterojunctions. The advantages of GBHJ structures in yielding an improved η have been explained through an increased exciton dissociation process along with a lower carrier recombination as compared to the bilayer and the BHJ structures, respectively. Series and shunt resistances, which were derived from current-voltage characteristics and impedance spectroscopy, supported such analyses.
Hydrothermal synthesis of Co3O4 nanowire electrocatalysts for oxygen evolution reaction
Authors: Xu Shuai , Tong Jinlin , Liu Yuan , Hu Wei , Zhang Ganbing , Xia Qinghua
Published: August 2016

Herein, we reported a well-controlled hydrothermal synthesis of Co3O4 nanowires using CoSO4 as a cobalt precursor and glycerol as a morphological directing agent. Scanning electron microscopy was employed to observe the growth of nanowires. As an important synthetic parameter, reaction time is spanned from 4 to 24 h, which played an important role in the morphology and properties of materials. When the reaction time was 4 h, the resulting Co3O4 nanoparticles assembled into some short nanorods. While increasing the reaction time, the nanorods grew into long nanowires with large aspect ratio, and then attached into bundles when the reaction time was extended up to 24 h. Electrochemical characterization shows that Co3O4 nanowires prepared by hydrothermal reaction for 12 h exhibited the highest catalytic activity for oxygen evolution reaction (OER) among all synthesized nanowires and nanoparticles using the similar method. The enhanced OER activity of the 12 h-prepared Co3O4 nanowires should be attributed to the increased electroactive surface area because observed from the cyclic voltammogram, the 12 h-prepared Co3O4 nanowires possessed the highest surface area among all tested samples. It was also illustrated that there existed a close correlation of the OER catalytic activity with the transition of oxidation state and the density of activity sites of the catalyst exposing to the electrolyte solution during the electrolysis. Though both Co3O4 nanowires and nanoparticles exhibited a considerable loss in OER activity during the stability testing, after polarization for 4 h at 1.7 V (versus a reversible hydrogen electrode), the Co3O4 nanowires still produced the higher catalytic current than that of the Co3O4 nanoparticles showing a slightly higher stability than the particles because of the nanowire structure.
Enhancement of carrier lifetimes in type-II quantum dot/quantum well hybrid structures
Authors: Couto O. D. D. , de Almeida P. T. , dos Santos G. E. , Balanta M. A. G. , Andriolo H. F. , Brum J. A. , Brasil M. J. S. P. , Iikawa F. , Liang B. L. , Huffaker D. L.
Published: August 2016

We investigate optical transitions and carrier dynamics in hybrid structures containing type-I GaAs/AlGaAs quantum wells (QWs) and type-II GaSb/AlGaAs quantum dots (QDs). We show that the optical recombination of photocreated electrons confined in the QWs with holes in the QDs and wetting layer can be modified according to the QW/QD spatial separation. In particular, for low spacer thicknesses, the QW optical emission can be suppressed due to the transference of holes from the QW to the GaSb layer, favoring the optical recombination of spatially separated carriers, which can be useful for optical memory and solar cell applications. Time-resolved photoluminescence (PL) measurements reveal non-exponential recombination dynamics. We demonstrate that the PL transients can only be quantitatively described by considering both linear and quadratic terms of the carrier density in the bimolecular recombination approximation for type-II semiconductor nanostructures. We extract long exciton lifetimes from 700 ns to 5 μs for QDs depending on the spacer layer thickness.
Magnetic fingerprint of interfacial coupling between CoFe and nanoscale ferroelectric domain walls
Authors: Zhang Qintong , Murray Peyton , You Lu , Wan Caihua , Zhang Xuan , Li Wenjing , Khan Usman , Wang Junling , Liu Kai , Han Xiufeng
Published: August 2016

Magnetoelectric coupling in ferromagnetic/multiferroic systems is often manifested in the exchange bias effect, which may have combined contributions from multiple sources, such as domain walls, chemical defects, or strain. In this study we magnetically “fingerprint” the coupling behavior of CoFe grown on epitaxial BiFeO3 (BFO) thin films by magnetometry and the first-order-reversal-curves (FORC). The contribution to exchange bias from 71°, 109° and charged ferroelectric domain walls (DWs) was elucidated by the FORC distribution. CoFe samples grown on BFO with 71° DWs only exhibit an enhancement of the coercivity, but little exchange bias. Samples grown on BFO with 109° DWs and mosaic DWs exhibit a much larger exchange bias, with the main enhancement attributed to 109° and charged DWs. Based on the Malozemoff random field model, a varying-anisotropy model is proposed to account for the exchange bias enhancement. This work sheds light on the relationship between the exchange bias effect of the CoFe/BFO heterointerface and the ferroelectric DWs, and provides a path for multiferroic device analysis and design.
Maximum anode chamber volume and minimum anode area for supporting electrogenesis in microbial fuel cells treating wastewater
Authors: Ghadge Anil N. , Ghangrekar Makarand M. , Scott Keith
Published: August 2016

During scale-up of microbial fuel cell (MFC), a proportional increment in power does not usually occur determining the importance of maximum possible anode chamber volume (Van) to exploit electrogenesis and achieve maximum energy recovery. A systematic approach is proposed for determining the optimal single anode chamber volume and the minimum anode surface area (Aan) of an MFC. The optimal anode chamber volume was estimated based on the substrate required to produce a defined maximum current that is likely to be produced from the basic electromotive force equation. The Aan was obtained by considering the area required for biofilm formation, the substrate utilization rate by electrogens, the MFC polarization curve, charge transfer kinetics and mass transport overpotential. Based on the theoretical bio-electrochemical considerations, the maximum Van and minimum Aan required for each anode chamber are proposed for electrogenesis to dominate. A single Van of a few litres will only be optimal for treating wastewater. With wastewater of chemical oxygen demand (COD) of 5 g l−1 and considering a Coulombic efficiency and a COD removal of 80% each, a Van of 2.02 l is optimum for a single anode chamber to produce a current up to 750 mA; which is the maximum possible current estimated from electromotive force equation. Any additional volume provided will leave the substrate unused by electrogens and encourage methanogenesis. Adopting this volume for each anode chamber in a MFC stack is recommended for treating wastewater under the assumptions of the analysis. Charge transfer kinetics dominate the minimum Aan required, which satisfies the area required for biofilm formation, MFC polarization, and mass transfer. The minimum Aan should be provided in a MFC to ensure the dominance of electrogenesis.
Peculiar temperature dependence of electric-field effect on magnetic anisotropy in Co/Pd/MgO system
Authors: Hibino Y. , Koyama T. , Obinata A. , Hirai T. , Ota S. , Miwa K. , Ono S. , Matsukura F. , Ohno H. , Chiba D.
Published: August 2016

We report on the temperature dependence of the magnetic anisotropy in Co/Pd/MgO system, in which magnetic moment in Pd is induced by the magnetic proximity effect. We demonstrate that the magnetic anisotropy is modulated by applying an electric field to the Pd surface. At temperatures below 100 K, we find the nonlinear electric-field dependence of the anisotropy with the sign reversal. We obtain a huge anisotropy modulation efficiency of ∼1600 fJ/V m at 10 K.
Effects of domain size on x-ray absorption spectra of boron nitride doped graphenes
Authors: Li Xin , Hua Weijie , Wang Bo-Yao , Pong Way-Faung , Glans Per-Anders , Guo Jinghua , Luo Yi
Published: August 2016

Doping is an efficient way to open the zero band gap of graphene. The control of the dopant domain size allows us to tailor the electronic structure and the properties of the graphene. We have studied the electronic structure of boron nitride doped graphenes with different domain sizes by simulating their near-edge X-ray absorption fine structure (NEXAFS) spectra at the N K-edge. Six different doping configurations (five quantum dot type and one phase-separated zigzag-edged type) were chosen, and N K-edge NEXAFS spectra were calculated with large truncated cluster models by using the density functional theory with hybrid functional and the equivalent core hole approximation. The opening of the band gap as a function of the domain size is revealed. We found that nitrogens in the dopant boundary contribute a weaker, red-shifted π* peak in the spectra as compared to those in the dopant domain center. The shift is related to the fact that these interfacial nitrogens dominate the lowest conduction band of the system. Upon increasing the domain size, the ratio of interfacial atom decreases, which leads to a blue shift of the π* peak in the total NEXAFS spectra. The spectral evolution agrees well with experiments measured at different BN-dopant concentrations and approaches to that of a pristine h-BN sheet.
Controlled vapour-phase deposition synthesis and growth mechanism of Bi2Te3 nanostructures
Authors: Lei W. , Madni I. , Ren Y. L. , Yuan C. L. , Luo G. Q. , Faraone L.
Published: August 2016

This work presents a study on the controlled growth and the growth mechanism of vapour-phase deposited two-dimensional Bi2Te3 nanostructures by investigating the influence of growth conditions on the morphology of Bi2Te3 nanostructures. The formation of a hexagonal plate geometry for Bi2Te3 nanostructures is a consequence of the large difference in growth rate between crystal facets along 〈0001〉 and 〈112¯0〉 directions. Under low Ar carrier gas flow rates (60–100 sccm), the growth of Bi2Te3 nanoplates occurs in the mass-transport limited regime, whereas under high carrier gas flow rates (130 sccm), the growth of Bi2Te3 nanoplates is in the surface-reaction limited regime. This leads to an increase in the lateral size of Bi2Te3 nanoplates with increasing the Ar carrier gas flow rate from 60 to 100 sccm, and a decrease in size for a flow rate of 130 sccm. In addition, the lateral size of Bi2Te3 nanoplates was found to increase with increasing growth time due to the kinetic characteristics of material growth. The proposed growth model provides an effective guide for achieving controlled growth of Bi2Te3 nanoplates, as well as other two dimensional nanomaterials.
Room temperature deintercalation of alkali metal atoms from epitaxial graphene by formation of charge-transfer complexes
Authors: Shin H.-C. , Ahn S. J. , Kim H. W. , Moon Y. , Rai K. B. , Woo S. H. , Ahn J. R.
Published: August 2016

Atom (or molecule) intercalations and deintercalations have been used to control the electronic properties of graphene. In general, finite energies above room temperature (RT) thermal energy are required for the intercalations and deintercalations. Here, we demonstrate that alkali metal atoms can be deintercalated from epitaxial graphene on a SiC substrate at RT, resulting in the reduction in density of states at the Fermi level. The change in density of states at the Fermi level at RT can be applied to a highly sensitive graphene sensor operating at RT. Na atoms, which were intercalated at a temperature of 80 °C, were deintercalated at a high temperature above 1000 °C when only a thermal treatment was used. In contrast to the thermal treatment, the intercalated Na atoms were deintercalated at RT when tetrafluorotetracyanoquinodimethane (F4-TCNQ) molecules were adsorbed on the surface. The RT deintercalation occurred via the formation of charge-transfer complexes between Na atoms and F4-TCNQ molecules.
Accurate electron affinity of Pb and isotope shifts of binding energies of Pb−
Authors: Chen Xiaolin , Ning Chuangang
Published: August 2016

Lead (Pb) was the last element of the group IVA whose electron affinity had a low accuracy around 10 meV before the present work. This was due to the generic threshold photodetachment measurement that cannot extent well below 0.5 eV due to the light source limitation. In the present work, the electron affinity of Pb was determined to be 2877.33(13) cm−1 or 0.356 743(16) eV for the isotope m = 208. The accuracy was improved by a factor of 500 with respect to the previous laser photodetachment electron spectroscopy. Moreover, remarkable isotope shifts of the binding energy of Pb− 6p3 4S3/2 − Pb 6p2 3P2 were observed for m = 206, 207, and 208.
Supercontinuum Fourier transform spectrometry with balanced detection on a single photodiode
Authors: Goncharov Vasily V. , Hall Gregory E.
Published: August 2016

We demonstrate a method of combining a supercontinuum light source with a commercial Fourier transform spectrometer, using a novel approach to dual-beam balanced detection, implemented with phase-sensitive detection on a single light detector. A 40 dB reduction in the relative intensity noise is achieved for broadband light, analogous to conventional balanced detection methods using two matched photodetectors. Unlike conventional balanced detection, however, this method exploits the time structure of the broadband source to interleave signal and reference pulse trains in the time domain, recording the broadband differential signal at the fundamental pulse repetition frequency of the supercontinuum. The method is capable of real-time correction for instability in the supercontinuum spectral structure over a broad range of wavelengths and is compatible with commercially designed spectrometers. A proof-of-principle experimental setup is demonstrated for weak absorption in the 1500-1600 nm region.
Magnetoresistance effect in Fe20Ni80/graphene/Fe20Ni80 vertical spin valves
Authors: Entani Shiro , Seki Takeshi , Sakuraba Yuya , Yamamoto Tatsuya , Takahashi Saburo , Naramoto Hiroshi , Takanashi Koki , Sakai Seiji
Published: August 2016

Vertical spin valve devices with junctions of single- and bi-layer graphene interlayers sandwiched with Fe20Ni80 (Permalloy) electrodes were fabricated by exploiting the direct growth of graphene on the Permalloy. The linear current-voltage characteristics indicated that ohmic contacts were realized at the interfaces. The systematic characterization revealed the significant modification of the electronic state of the interfacial graphene layer on the Permalloy surface, which indicates the strong interactions at the interface. The ohmic transport was attributable to the strong interface-interaction. The vertical resistivity of the graphene interlayer and the spin asymmetry coefficient at the graphene/Permalloy interface were obtained to be 0.13 Ω cm and 0.06, respectively. It was found that the strong interface interaction modifies the electronic structure and metallic properties in the vertical spin valve devices with bi-layer graphene as well as single-layer graphene.
Communication: Variation after response in quantum Monte Carlo
Authors: Neuscamman Eric
Published: August 2016

We present a new method for modeling electronically excited states that overcomes a key failing of linear response theory by allowing the underlying ground state ansatz to relax in the presence of an excitation. The method is variational, has a cost similar to ground state variational Monte Carlo, and admits both open and periodic boundary conditions. We present preliminary numerical results showing that, when paired with the Jastrow antisymmetric geminal power ansatz, the variation-after-response formalism delivers accuracies for valence and charge transfer single excitations on par with equation of motion coupled cluster, while surpassing coupled cluster’s accuracy for excitations with significant doubly excited character.
Scaling of the anomalous Hall effect in epitaxial antiperovskite Mn3.5Dy0.5N involving multiple competing scattering mechanisms
Authors: Meng M. , Wu S. X. , Zhou W. Q. , Li S. W.
Published: August 2016

Anomalous Hall effect (AHE) has been studied for ferrimagnetic antiperovskite Mn3.5Dy0.5N film grown by molecular-beam epitaxy. Reflective high energy electron diffraction and transmission electron microscopy demonstrate the high quality of the film. We have used a scaling involving multiple competing scattering mechanisms to distinguish variations of contributions to the AHE by heavily doped Dy. The scaling analysis revealed that the heavily doped Dy has dramatically modified the skew scattering part of the AHE in Mn4N and Mn3.5Dy0.5N has a totally different scattering mechanism from an undoped film.
Influence of internal geometry on magnetization reversal in asymmetric permalloy rings
Authors: Gopman D. B. , Kabanov Y. P. , Cui J. , Lynch C. S. , Shull R. D.
Published: August 2016

We report the magnetization reversal behavior of microstructured Ni80Fe20 rings using magneto-optic indicator film imaging and magnetometry. While the reversal behavior of rings with a symmetric (circular) interior hole agrees with micromagnetic simulations of an onion → vortex → onion transition, we experimentally demonstrate that rings possessing an elliptical hole with an aspect ratio of 2 exhibit complex reversal behavior comprising incoherent domain propagation in the rings. Magneto optic images reveal metastable magnetic configurations that illustrate this incoherent behavior. These results have important implications for understanding the reversal behavior of asymmetric ferromagnetic rings.
Fabrication and independent control of patterned polymer gate for a few-layer WSe2 field-effect transistor
Authors: Hong Sung Ju , Park Min , Kang Hojin , Lee Minwoo , Jeong Dae Hong , Park Yung Woo
Published: August 2016

We report the fabrication of a patterned polymer electrolyte for a two-dimensional (2D) semiconductor, few-layer tungsten diselenide (WSe2) field-effect transistor (FET). We expose an electron-beam in a desirable region to form the patterned structure. The WSe2 FET acts as a p-type semiconductor in both bare and polymer-covered devices. We observe a highly efficient gating effect in the polymer-patterned device with independent gate control. The patterned polymer gate operates successfully in a molybdenum disulfide (MoS2) FET, indicating the potential for general applications to 2D semiconductors. The results of this study can contribute to large-scale integration and better flexibility in transition metal dichalcogenide (TMD)-based electronics.
Na
+
coordination at the Na2 site of the Na
+
/I
−
symporter
Authors: Ferrandino Giuseppe , Nicola Juan Pablo , Sánchez Yuly E. , Echeverria Ignacia , Liu Yunlong , Amzel L. Mario , Carrasco Nancy
Published: August 2016

Significance

The Na
+
/I
−
symporter (NIS) uses the Na
+
electrochemical gradient to actively transport I
−
into the thyroid with a 2 Na
+
:1 I
−
stoichiometry. In NIS and related transporters, one of the two Na
+
binding sites, Na2, includes a Ser and a Thr residue. We determined that, besides these residues, four other amino acids participate in binding Na
+
at the Na2 site, at different stages of the transport cycle. These residues are conserved throughout the entirety of solute carrier family 5 (SLC5), to which NIS belongs. Replacing any of these residues has a marked effect on transport and on the dynamics of NIS. These results not only deepen our understanding of the mechanism of transport by NIS but are also relevant to the study of other Na
+
-driven cotransporters.
Codeswitching and identity among Island Puerto Rican bilinguals
Authors: Pérez Casas Marisol
Published: August 2016

This study investigates how a network of elite, educated bilinguals on the Island of Puerto Rico (PR) alternate between English and Spanish in everyday, casual conversations, and how their choice of language relates to their social identities. Due to the complex relationship between Spanish and English in PR this context is ideal for looking into the meaning and social significance of CS, and how individual creativity and collective social knowledge intersect in identity creation. Ethnographic interviews and observations, audio recording of casual conversations, and a thorough understanding of speakers’ socio-cultural realities revealed the development of the communicative style of CS, and its relationship to the enactment, reproduction, and shaping of the following identity categories: ‘elite,’ ‘American,’ and ‘Puerto Rican.’
Socio-pragmatic functions of codeswitching in Nuyorican & Cuban American literature
Authors: Montes-Alcalá Cecilia
Published: August 2016

This chapter emphasizes the social, pragmatic, and cultural nature of codeswitching (CS) over the search for grammatical constraints on the phenomenon. While the bulk of research performed on language mixing has concentrated on spontaneous oral production, the present investigation focuses on CS in literary writing. Through the quantitative and qualitative analysis of a selection of contemporary Nuyorican and Cuban American bilingual literature (poetry, drama, and fiction) the goal of the study is to determine the extent to which literary CS reflects ordinary bilingual speech and performs socio-pragmatic functions similar to those ascribed to natural bilingual discourse. It also seeks to establish whether literary CS displays any substantial differences across genres and/or between the two groups analyzed.
The importance of prescriptivism in the development of “schemes for respelling” in 18th century pronouncing dictionaries
Authors: Pouillon Véronique
Published: August 2016

This paper will give an overview of the evolution of phonic descriptions in 18th century English pronouncing dictionaries, and of the role of prescriptivism within this process. The prescriptive attitudes of orthoepists during this period led them to adopt increasingly detailed and precise transcription systems, and this same prescriptivism, informed by graphocentrism, influenced these systems as well as the individual transcriptions.
Our aim is to establish that the prescriptive tendencies that hardened in 18th century England (during the period which saw the rise of what would come to be known as Received Pronunciation) served as a catalyst for a more systematic approach to describing spoken language and graphophonemic conventions. This is linked to prescriptivism as a tool for social demarcation, and a pedagogical necessity, but also as the hallmark of the traditional, accretive approach to knowledge, of which graphocentric bias is one example.
Els discursos sobre la llengua literària en la Renaixença valenciana / Discourses on literary language in the Valencian Renaissance
Authors: Roca Ricart Rafael
Published: August 2016

When Pompeu Fabra wrote his famous article in 1918, later entitled “La tasca dels escriptors valencians i balears” (The task of Valencian and Balearic writers), he was simply echoing two of the main issues which Valencian writers had been struggling with for about 40 years: the purification of literary language and the subordination of their dialect to the one used in Catalonia. Thus, this paper examines some of the linguistic difficulties which the writers of the Valencian Renaissance stumbled over, such as the doubts and obstacles posed by decastilianization and the setting of the high variety of the language, and also the opposition from many influential social sectors against linguistic and literary recovery, which was considered politically based. Another problem was the fierce resistance from Valencian society when having to accept and apply the name of the shared language “Catalan” to their own.
Le mythe de la langue mère / The myth of the mother tongue
Authors: Auroux Sylvian
Published: August 2016

Our linguistic history is full of myths. There is the myth of the national language, the one of a particular genius of each language. Insofar as national languages are artifacts built by centuries of language policy and by the careful equipping of the major culture’s languages through language instruments that are (among others) translation manuals, dictionaries and grammars, we can assume that the idea of a “language” isotopic and regular before any human intervention is also a myth. In what follows, I shall endeavor to unravel a particular myth; that of the original mother tongue of mankind. This myth has one very special feature: it was created by the scientific community and has resurfaced again after seemingly having had its fate sealed.
Mitos de decadencia lingüística en la historia del neerlandés. Una exploración sociolingüística de la lengua en Flandes en los siglos xviii y xix / Myths of language decadence in Dutch history. A sociolinguistic exploration of language in Flanders in the eighteenth and nineteenth centuries
Authors: Vosters Rik
Published: August 2016

Contrary to the fixed language norms of Northern (“Hollandic”) Dutch, Southern (“Flemish”) Dutch in the eighteenth and nineteenth century is claimed to have been nothing more than a collection of mutually unintelligible and Frenchified dialects. Such discourses of Southern linguistic chaos lie at the basis of Hollandic varieties serving as the foundation for the modern-day standard language. In this contribution, I will identify and trace back several “myths of linguistic decay” in a collection of normative works and metalinguistic texts, and test them against findings from actual usage, based on a corpus of handwritten documents from the early nineteenth century. By examining adnominal case and gender marking as a representative case study, I will show how the divide between the North and the South existed not only on the linguistic level, but thrived all the more on the metalinguistic level.
De llengües, mites i emocions al xix català: el mite de la llengua del cor? / Language, myths and emotions in nineteenth-century Catalan: The myth of the language of the heart?
Authors: Ginebra Jordi
Published: August 2016

At the beginning of the nineteenth century very few reasons remained to support the claim that the Catalan language would play a significant role in the future of Catalonia. The opinion was that, if the teaching of Spanish was both good and well established, the Catalans would give up their own language without any problems. However, one hundred years later, at the beginning of the twentieth century, different factors have emerged that have refuelled the debate in favour of Catalan. It is generally claimed that cultural links between languages and nations were established during the Romantic period. Indeed, language became the source of nationhood. Nevertheless, Romanticism not only raised the collective cultural dimension of languages, but also legitimized the emotional links between individuals and their own language. Thus, Catalan as a mother tongue achieves a new value and significance: it becomes the language of the heart and soul, the language of sincerity and authenticity.
Functional analyses of chitinases in the moss Physcomitrella patens: chitin oligosaccharide-induced gene expression and enzymatic characterization
Authors: Kobaru Saki , Tanaka Ryusuke , Taira Toki , Uchiumi Toshiki
Published: August 2016

Plant chitinases play diverse roles including defense against pathogenic fungi. Using reverse-transcription quantitative PCR analysis, we found that six chitinase (PpChi) genes and two genes for chitin elicitor receptor kinases (PpCERKs) are expressed at considerable levels in the moss Physcomitrella patens subsp. patens. The expressed PpChis belonged to glycoside hydrolase family 19 (class I: PpChi-Ia and -Ib; class II: PpChi-IIa and -IIc; and class IV: PpChi-IV) and to glycoside hydrolase family 18 (class V: PpChi-Vb). Treatment with chitin tetramer or hexamer increased the expression of class I and IV PpChi genes and decreased that of class II PpChi genes. Recombinant PpChi-Ia, PpChi-IV, and PpChi-Vb were characterized. PpChi-IV exhibited higher activity against chitin tetramer and pentamer than PpChi-Ia did. PpChi-Vb showed transglycosylation activity and PpChi-Ia inhibited fungal growth. These results suggest that chitinases of different classes play different roles in defense mechanism of moss plant against fungal pathogens.
Effects of Liming on Quality of Water Discharged from the Supply Reservoir at a Fisheries Research Station
Authors: Somridhivej Benjaporn , Boyd Claude E
Published: August 2016

Annual treatment of a water supply reservoir with agricultural limestone at the E. W. Shell Fisheries Center at Auburn University has roughly doubled conductivity and concentrations of total alkalinity, total hardness, and calcium hardness in the discharge water. It also has prevented pH values below 6.7. Concentrations of water quality variables decreased following some large rainfall events and during periods of prolonged rainfall. Calcium hardness concentrations were sometimes lower than recommended for hatchery water supplies intended for Channel Catfish Ictalurus punctatus. Nevertheless, liming has improved the quality of the reservoir discharge for use in both the hatchery and research ponds at the station.
Feasibility of Oxytetracycline Marking Fingerling White Bass
Authors: Perrion Matthew A , Schall Benjamin J , Schoenebeck Casey W , Koupal Keith D , Sweet Bryan D
Published: August 2016

Chemical batch marks with compounds such as oxytetracycline hydrochloride (OTC) can be useful for estimates of stock contribution. However, no information currently exists on the feasibility of marking fingerling White Bass Morone chrysops with OTC. The objectives of this study were to determine the level of mortality on White Bass when immersed in solutions of OTC at 0, 350, and 500 mg/L at intervals up to 96 h postimmersion and to assess the quality of marks on sagittal otoliths 14 d postmarking. A total of 900 White Bass (29–41 mm) were utilized with 100 fish used in three replicates per treatment. No differences in mortality rates were detected among control and treatment groups up to 96 h postmarking. Cumulative mortality rates were ≤6.7%. Mark visibility was ranked on a scale of 0–3; mean mark score was higher in the 500-mg/L treatment (2.5) than the 350-mg/L treatment (2.0). Batch-marking fingerling White Bass using the 500-mg/L marking solution provided visible marks and low mortality rates and therefore represents a viable option for biologists seeking to assess stock contribution and year-class strength.
The European VAT Oxymoron: A pragmatic solution for welfare, especially in times of crisis?
Authors: Polomarkakis Konstantinos Alexandris
Published: August 2016

VAT is an important but at the same time long neglected issue in social policy literature. The way in which taxes are levied has important implications for citizens in terms of equity and efficiency effects. Rate diversification is embedded in VAT planning across the EU, which enables Member States to address particular welfare objectives and tackle VAT's regressivity. Nonetheless, for some, this undermines the uniformity and effectiveness of a pan-European VAT system comprised of the so-called ideal single-rate VAT structure which could bring more money into state budgets and, thus, allow for more generous welfare provision. This paper evaluates arguments put forward by both sides, concluding that in times of crisis, where governments might advance VAT streamlining purely in order to deal with deficit constraints instead of fairer redistribution, the regime currently in place is the most pragmatic solution from a pro-welfare perspective.
Interpreting Heritability Causally
Authors: Lynch Kate E. , Bourrat Pierrick
Published: August 2016

A high heritability estimate usually corresponds to a situation in which trait variation is largely caused by genetic variation. However, in some cases of gene-environment covariance, causal intuitions about the sources of trait difference can vary, leading experts to disagree as to how the heritability estimate should be interpreted. We argue that the source of contention for these cases is an inconsistency in the interpretation of the concepts ‘genotype’, ‘phenotype’, and ‘environment’. We propose an interpretation of these terms under which trait variance initially caused by genetic variance is subsumed into a heritability for all cases of gene-environment covariance.
Understanding Polarization: Meanings, Measures, and Model Evaluation
Authors: Bramson Aaron , Grim Patrick , Singer Daniel J. , Berger William J. , Sack Graham , Fisher Steven , Flocken Carissa , Holman Bennett
Published: August 2016

Polarization is a topic of intense interest among social scientists, but there is significant disagreement regarding the character of the phenomenon and little understanding of underlying mechanics. A first problem, we argue, is that polarization appears in the literature as not one concept but many. In the first part of the article, we distinguish nine phenomena that may be considered polarization, with suggestions of appropriate measures for each. In the second part of the article, we apply this analysis to evaluate the types of polarization generated by the three major families of computational models proposing specific mechanisms of opinion polarization.
Assembly-based inference of B-cell receptor repertoires from short read RNA sequencing data with V’DJer
Authors: Mose Lisle E. , Selitsky Sara R. , Bixby Lisa M. , Marron David L. , Iglesia Michael D. , Serody Jonathan S. , Perou Charles M. , Vincent Benjamin G. , Parker Joel S.
Published: August 2016

Motivation: B-cell receptor (BCR) repertoire profiling is an important tool for understanding the biology of diverse immunologic processes. Current methods for analyzing adaptive immune receptor repertoires depend upon PCR amplification of VDJ rearrangements followed by long read amplicon sequencing spanning the VDJ junctions. While this approach has proven to be effective, it is frequently not feasible due to cost or limited sample material. Additionally, there are many existing datasets where short-read RNA sequencing data are available but PCR amplified BCR data are not.

Results: We present here V’DJer, an assembly-based method that reconstructs adaptive immune receptor repertoires from short-read RNA sequencing data. This method captures expressed BCR loci from a standard RNA-seq assay. We applied this method to 473 Melanoma samples from The Cancer Genome Atlas and demonstrate V’DJer’s ability to accurately reconstruct BCR repertoires from short read mRNA-seq data.

Availability and Implementation: V’DJer is implemented in C/C ++, freely available for academic use and can be downloaded from Github: https://github.com/mozack/vdjer

Contact:  benjamin_vincent@med.unc.edu or parkerjs@email.unc.edu

Supplementary information:  Supplementary data are available at Bioinformatics online.
Core deficits and quality of survival after childhood medulloblastoma: a review
Authors: Chevignard Mathilde , Câmara-Costa Hugo , Doz François , Dellatolas Georges
Published: August 2016

Background.

Medulloblastoma is the most common malignant central nervous system tumor in children. Treatment most often includes surgical resection, craniospinal irradiation, and adjuvant chemotherapy. Although survival has improved dramatically, the tumor and its treatments have devastating long-term side effects that negatively impact quality of survival (QoS). The objective was to review the literature on QoS following childhood medulloblastoma.

Methods.

This narrative review is based on a Medline database search and examination of the reference lists of papers selected.

Results.

Frequent problems after medulloblastoma treatment include medical complications, such as long-term neurological and sensory (hearing loss) impairments; endocrine deficits, including growth problems; and secondary tumors. Neurocognitive impairment is repeatedly reported, with decreasing cognitive performances over time. Although all cognitive domains may be affected, low processing speed, attention difficulties, and working memory difficulties are described as the core cognitive deficits resulting from both cerebellar damage and the negative effect of radiation on white matter development. Long-term psychosocial limitations include low academic achievement, unemployment, and poor community integration with social isolation. Important negative prognostic factors include young age at diagnosis, conventional craniospinal radiotherapy, presence of postoperative cerebellar mutism, and perioperative complications. The influence of environmental factors, such as family background and interventions, remains understudied.

Conclusion.

Future studies should focus on the respective impact of radiation, cerebellar damage, genomic and molecular subgroup parameters, and environmental factors on cognitive and psychosocial outcomes. Long-term (probably lifelong) follow-up into adulthood is required in order to monitor development and implement timely, suitable, multi-disciplinary rehabilitation interventions and special education or support when necessary.
Creating a caregiver program in neuro-oncology
Authors: Page Margaretta S. , Chang Susan M.
Published: August 2016

Background.

Neuro-oncology caregivers face unique challenges. Caring for a patient who has a catastrophic, life-threatening diagnosis combined with progressive neurological decline can produce great distress. Experts agree that a formalized plan of care to address the needs of the neuro-oncology caregiver is needed.

Methods.

In 2013, the Division of Neuro-Oncology at the University of California, San Francisco initiated a program designed to provide additional services to address the needs of the neuro-oncology caregiver. Records have been kept outlining program development, the caregivers seen, their identified needs, and services provided.

Results.

From October 2013 through August 2015 staff met with 334 “new to clinic” caregivers, 90 of whom were caring for patients with newly diagnosed glioblastoma. One hundred ninety-eight caregivers were deemed at high risk for distress due to transitions in patient care that were occurring. One hundred forty-nine caregivers of former patients received bereavement services for up to 6 months. The areas of highest need were emotional support and advocacy issues. The number of caregiver needs increased as patients moved along the disease trajectory. The program was able to identify resources that were lacking. Dedicated staff allowed for improvement in the kinds of caregiver-specific support services offered.

Conclusion.

Dedicated caregiver staff allows for developing relationships with caregivers across the disease trajectory and appears to be important in being able to offer individualized assessments and tailored care plans. Evaluation of caregiver and patient outcomes is the next step in understanding program effectiveness.
Why Does Threshold Level Change in Transcranial Motor-evoked Potentials During Surgery for Supratentorial Lesions?
Authors: Abboud Tammam , Huckhagel Torge , Stork Jan-Henrich , Hamel Wolfgang , Schwarz Cindy , Vettorazzi Eik , Westphal Manfred , Martens Tobias
Published: August 2016

Background:

Rising threshold level during monitoring of motor-evoked potentials (MEP) using transcranial electrical stimulation (TES) has been described without damage to the motor pathway in the cranial surgery, suggesting the need for monitoring of affected and unaffected hemisphere. We aimed to determine the factors that lead to a change in threshold level and to establish reliable criteria for adjusting stimulation intensity during surgery for supratentorial lesions.

Materials and Methods:

Between October 2014 and October 2015, TES-MEP were performed in 143 patients during surgery for unilateral supratentorial lesions in motor-eloquent brain areas. All procedures were performed under general anesthesia using a strict protocol to maintain stable blood pressure. MEP were evaluated bilaterally to assess the percentage increase in threshold level, which was considered significant if it exceeded 20% on the contralateral side beyond the percentage increase on the ipsilateral side. Patients who developed a postoperative motor deficit were excluded. Volume of subdural air was measured on postoperative magnetic resonance imaging. Logistic regression was performed to identify factors associated with the intraoperative recorded changes in threshold level.

Results:

A total of 123 patients were included in the study. On the affected side, 82 patients (66.7%) showed an increase in threshold level, which ranged from 2% to 48% and 41 patients (33.3%) did not show any change. The difference to the unaffected side was under 20% in all patients. The recorded range of changes in the systolic and mean pressure did not exceed 20 mm Hg in any of the patients. Pneumocephalus was detected on postoperative magnetic resonance imaging scans in 87 patients (70.7%) and 81 of them (93.1%) had an intraoperative increase in threshold level on either sides. Pneumocephalus was the only factor associated with an increase in threshold level on the affected side (P<0.001), while each of pneumocephalus and length of the procedure correlated with a change in threshold level on the unaffected side (P<0.001 and 0.032, respectively).

Conclusions:

Pneumocephalus was the only factor associated with increase in threshold level during MEP monitoring without damaging motor pathway. Threshold level on the affected side can rise up to 48% without being predictive of postoperative paresis, as long as the difference between the increased threshold of the affected and unaffected side is within 20%. Changes in systolic or mean blood pressure within a range of 20 mm Hg do not seem to influence intraoperative MEP.
What Next After GAS and PANDA?
Authors: Ing Caleb , Rauh Virginia A. , Warner David O. , Sun Lena S.
Published: August 2016

On April 16 and 17, 2016, the Fifth biennial Pediatric Anesthesia & Neurodevelopment Assessment (PANDA) symposium was convened at the Morgan Stanley Children’s Hospital of New York at Columbia University Medical Center. During the symposium, experts in the fields of anesthesiology, neuropsychology, and epidemiology were convened in a small group session to determine the level of confidence in the current clinical evidence and the next steps in anesthetic neurotoxicity clinical research. Among the participants in the discussion, there remained a lack of consensus on whether anesthetic exposure causes long-term neurodevelopmental deficits in children based on the current evidence. This causal relationship between anesthesia exposure and neurodevelopmental deficit is difficult to establish using observational data, and current and future clinical trials are critical for answering this question. It was, however, recognized that the continuum of data that is seen in studies of other toxic environmental exposures, such as lead poisoning, has not been established in the anesthetic neurotoxicity literature, specifically regarding the timing of the exposure, the dose effects, contributing perioperative conditions, or vulnerable populations. As a result, these questions may need to be addressed in observational studies to guide future clinical trials.
Biomarkers, Genetics, and Epigenetic Studies to Explore the Neurocognitive Effects of Anesthesia in Children
Authors: Levy Richard J. , Herbstman Julie B. , Bosnjak Zeljko J. , Loepke Andreas W. , McGowan Francis X.
Published: August 2016

Exposure to commonly used anesthetic agents causes widespread neuronal degeneration in the developing mammalian brain and has been shown to impair neurodevelopment in a variety of newborn vertebrate animal species. Although retrospective studies have suggested an association between anesthesia exposure in childhood and subsequent neurodevelopmental abnormalities, a causal relationship in humans has yet to be demonstrated. Unfortunately, translation of findings from bench to bedside is limited by several factors and histologic assessment in healthy children following exposure to anesthesia is not possible. Therefore, to prove that anesthesia-induced neurotoxicity occurs in humans, alternative approaches are necessary. Here we present the summary of a focus group discussion regarding the utility of biomarkers in translational studies of anesthetic neurotoxicity as part of The 2016 Pediatric Anesthesia NeuroDevelopmental Assessment (PANDA) Symposium at Columbia University Medical Center. The experts agreed that defining intermediate phenotypes using advanced neuroimaging as a biomarker is a highly feasible and reasonable modality to provide new insights into the deleterious effects of anesthetic exposure in the developing human brain and could illuminate a viable investigative path forward. Ultimately, well-defined intermediate phenotypes may allow us to fully understand the neurodevelopmental impact of anesthesia-induced neurotoxicity and permit us to develop the safest and most effective anesthetic strategies for the infants and children we care for.
Lessons Learned: Studying the Vulnerable Brain
Authors: Wolk Risa , Ko Riva R.
Published: August 2016

Neurotoxicity related to early exposure to various insults, both anesthesia-related and nonanesthesia-related, is a topic of ongoing and increasing interest. To better understand the process by which this might occur, the fifth PANDA Symposium convened a session in which 4 notable neuroscientists discussed current concepts and research in neurodevelopment, highlighting periods of particular susceptibility and ways in which neural connectivity and systemic functioning may be affected.