bluuebunny/crossref_metadata_2025 huggingface dataset:
Photo-lability of deep ocean dissolved black carbon
Authors: Stubbins A. , Niggemann J. , Dittmar T.
Published: May 2012

Abstract. Dissolved black carbon (DBC), defined here as condensed aromatics isolated from seawater via PPL solid phase extraction and quantified as benzenepolycarboxylic acid (BPCA) oxidation products, is a significant component of the oceanic dissolved organic carbon (DOC) pool. These condensed aromatics are widely distributed in the open ocean and appear to be tens of thousands of years old. As such DBC is regarded as highly refractory. In the current study, the photo-lability of DBC, DOC and coloured dissolved organic matter (CDOM; ultraviolet-visible absorbance) were determined over the course of a 28 day irradiation of North Atlantic Deep Water under a solar simulator. During the irradiation DBC fell from 1044 ± 164 nM-C to 55 ± 15 nM-C, a 20-fold decrease in concentration. Dissolved black carbon photo-degradation was more rapid and more extensive than for bulk CDOM and DOC. The concentration of DBC correlated with CDOM absorbance and the quality of DBC indicated by the ratios of different BPCAs correlated with CDOM absorbance spectral slope, suggesting the optical properties of CDOM may provide a proxy for both DBC concentrations and quality in natural waters. Further, the photo-lability of components of the DBC pool increased with their degree of aromatic condensation. These trends indicate that a continuum of compounds of varying photo-lability exists within the marine DOC pool. In this continuum, photo-lability scales with aromatic character, specifically the degree of condensation. Scaling the rapid photo-degradation of DBC to rates of DOC photo-mineralisation for the global ocean leads to an estimated photo-chemical half-life for oceanic DBC of less than 800 years. This is more than an order of magnitude shorter than the apparent age of DBC in the ocean. Consequently, photo-degradation is posited as the primary sink for oceanic DBC and the apparent survival of DBC molecules in the oceans for millennia appears to be facilitated not by their inherent inertness but by the rate at which they are cycled through the surface ocean's photic zone.
Partitioning of soil water among canopy trees during a soil desiccation period in a temperate mixed forest
Authors: Meißner M. , Köhler M. , Schwendenmann L. , Hölscher D.
Published: May 2012

Abstract. Complementary resource use is considered an important mechanism in the study of biodiversity effects. Here we explore how species identity, species mixture and tree size influence the vertical partitioning of soil water among canopy trees during a soil desiccation period. In the Hainich forest, Germany, the species Fagus sylvatica, Tilia sp. and Fraxinus excelsior were studied in single- and three-species mixed clusters, each consisting of three co-dominant trees situated within a larger mixed forest stand. Vertical soil water uptake depth was assessed by analyzing the hydrogen stable isotope composition (deuterium, δ D) of water from depth intervals throughout the soil profile and in tree xylem water. For single species clusters, a mixing model suggested that Fagus distinctively drew water from soil depths of 0.3–0.5 m, Tilia from 0.3–0.5 m and 0.5–0.7 m and Fraxinus mainly used water from 0.5–0.7 m. In mixed clusters, the uptake patterns of Fagus and Tilia were similar to those of the single-species clusters (mainly uptake form 0.3–0.5 m), but Fraxinus showed a different uptake pattern. Fraxinus in mixture had a somewhat homogenously distributed uptake over the soil depths 0.2–0.7 m. For single species clusters, there was no correlation between main soil water uptake depth and tree diameter, irrespective of variations in tree size. In contrast, for mixed clusters there was a significant decrease in the main uptake depth with increasing tree size (P<0.001, R2adj = 0.73), irrespective of species mix. In consequence, soil water partitioning was strongest where species were mixed and tree size varied. We further analyzed whether single and mixed-species clusters differed in the level of water uptake, e.g. due to complementarity, but our soil water budgeting did not indicate any such differences. A possible explanation might be that the volume of water used is predominantly governed by properties at the stand level, such as aerodynamic roughness, than by processes acting at the meter scale between neighbouring trees. With respect to application, we assume that the upcoming close-to-nature forestry approach for the area, which fosters mixed stands of heterogonous diameters, may result in enhanced complementarity in soil water uptake among canopy trees.
A dynamic continental runoff routing model applied to the last Northern Hemisphere deglaciation
Authors: Goelzer H. , Janssens I. , Nemec J. , Huybrechts P.
Published: May 2012

Abstract. We describe and evaluate a dynamical continental runoff routing model for the Northern Hemisphere that calculates the runoff pathways in response to topographic modifications due to changes in ice thickness and isostatic adjustment. The algorithm is based on the steepest gradient method and takes as simplifying assumption that depressions are filled at all times and water drains through the lowest outlet points. It also considers changes in water storage and lake drainage in post-processing mode that become important in the presence of large ice dammed proglacial lakes. Although applicable to other scenarios as well, the model was conceived to study the routing of freshwater fluxes during the last Northern Hemisphere deglaciation. For that specific application we simulated the Northern Hemisphere ice sheets with an existing 3-D thermomechanical ice sheet model, which calculates changes in topography due to changes in ice cover and isostatic adjustment, as well as the evolution of freshwater fluxes resulting from surface ablation, iceberg calving and basal melt. The continental runoff model takes this input, calculates the drainage pathways and routes the freshwater fluxes to the surface grid points of an existing ocean model. This results in a chronology of temporally and spatially varying freshwater fluxes from the Last Glacial Maximum to the present day. We analyse the dependence of the runoff routing to grid resolution and parameters of the isostatic adjustment module of the ice sheet model.
Hydrological responses to climate change conditioned by historic alterations of land-use and water-use
Authors: Jarsjö J. , Asokan S. M. , Prieto C. , Bring A. , Destouni G.
Published: May 2012

Abstract. This paper quantifies and conditions expected hydrological responses in the Aral Sea Drainage Basin (ASDB; occupying 1.3% of the earth's land surface), Central Asia, to multi-model projections of climate change in the region from 20 general circulation models (GCMs). The aim is to investigate how uncertainties of future climate change interact with the effects of historic human re-distributions of water for land irrigation to influence future water fluxes and water resources. So far, historic irrigation changes have greatly amplified water losses by evapotranspiration (ET) in the ASDB, whereas 20th century climate change has not much affected the regional net water loss to the atmosphere. Results show that errors in temperature (T) and precipitation (P) from single GCMs have large influence on projected change trends (for the period 2010–2039) of river runoff (R), even though the ASDB is spatially well resolved by current GCMs. By contrast, observed biases in GCM ensemble mean results have relatively small influence on projected R change trends. Ensemble mean results show that projected future climate change will considerably increase the net water loss to the atmosphere. Furthermore, the ET response strength to any future T change will be further increased by maintained (or increased) irrigation practices, which shows how climate change and water use change can interact in modifying ET (and R). With maintained irrigation practices, R is likely to decrease to near-total depletion, with risk for cascading ecological regime shifts in aquatic ecosystems downstream of irrigated land areas. Without irrigation, the agricultural areas of the principal Syr Darya river basin could sustain a 50% higher T increase (of 2.3 °C instead of the projected 1.5 °C until 2010–2039) before yielding the same consumptive ET increase and associated R decrease as with the present irrigation practices.
Teaching hydrological modeling with a user-friendly catchment-runoff-model software package
Authors: Seibert J. , Vis M. J. P.
Published: May 2012

Abstract. Computer models, and especially conceptual models, are frequently used for catchment hydrology studies. Teaching hydrological modeling, however, is challenging as students, when learning to apply computer models, have both to understand general model concepts and to be able to use particular computer programs. Here we present a new version of the HBV model. This software provides a user-friendly version which is especially useful for education. Different functionalities like an automatic calibration using a genetic algorithm or a Monte Carlo approach as well as the possibility to perform batch runs with predefined model parameters make the software also interesting for teaching in more advanced classes and research projects. Different teaching goals related to hydrological modeling are discussed and a series of exercises is suggested to reach these goals.
Characterizing interactions between surface water and groundwater in the Jialu River basin using major ion chemistry and stable isotopes
Authors: Yang L. , Song X. , Zhang Y. , Han D. , Zhang B. , Long D.
Published: May 2012

Abstract. The Jialu River, a secondary tributary of the Huaihe River, has been severely contaminated for the major contaminant sources, such as a number of untreated or lightly treated sewage wastes in some cities. Groundwater along the river is not an isolated component of the hydrologic system, but instead connected with the surface water. This study aims to characterize the relationships between surface water (e.g. reservoirs, lakes and rivers) and groundwater near the river in the shallow Quaternary aquifer. The concentration of Cl− in North Zhengzhou City increased prominently due to the discharge of a large amount of domestic water. Nitrate and potassium show maximum concentrations in groundwater in Fugou County. These high levels can be attributed to the use of a large quantity of fertilizer over this region. The regional well had water with a constant stable isotopic signature, which illustrates that the groundwater never or rarely receive recharge from surface water. However, the groundwater of transitional well (location SY3) seemed to be recharged by river water via bank infiltration in September 2010. Fractional contributions of river water to the groundwater were calculated based on isotopic and chemical data using a mass-balance approach. Results show that the groundwater was approximately composed of 60–70% river water. These findings would be useful for a better understanding of hydrogeological processes at the river-aquifer interface and ultimately benefit water management in the future.
Combined FTIR Matrix Isolation and Density Functional Studies of Indole-3-Pyruvic Acid Molecule. Spectroscopic Evidence of Gas-Phase Tautomerism
Authors: Bencivenni Luigi , Margonelli Andrea , Mariani Alessandro , Pieretti Andrea , Nunziante Cesaro Stella
Published: May 2012

The vibrational spectrum of matrix-isolated indole-3-pyruvic acid has been studied aiming to obtain information about the structures of the stable vapour-phase forms of the molecule. Together with results from theoretical density functional calculations, the spectroscopic data enable to undertake an attribution for most of the observed bands. The FTIR spectrum of crystalline indole-3-pyruvic acid has been compared with that of matrix isolation study.
Ultrasonographic Evaluation of Bowel Wall Thickness and Intramural Blood Flow in Ulcerative Colitis
Authors: Bavil Abolhassan Shakeri , Somi Mohommad Hossein , Nemati Masoud , Nadergoli Batool Seyfi , Ghabili Kamyar , Mirnour Reshad , Ashrafi Hamideh
Published: May 2012

Aim. This study aimed at assessing Doppler ultrasonographic findings of gut wall vessels and thickness in active and quiescent ulcerative colitis. Methods. Fifty patients with ulcerative colitis were studied using transabdominal grayscale and Doppler sonography of sigmoid, distal and middle parts of descending colon in different stages of the disease. Thickness of colon wall in the most involved site, number of color signals in each box, resistive index (RI), and pulsatility index (PI) were evaluated.
Results. The median thickness of the colon wall in the most involved sites was 4.3 mm in acute phase and 4.4 mm in the inactive phase (P=0.47). The median number of the color signals in the active phase at the most involved site, distal part of descending colon and sigmoid was higher than that of the color signals in the inactive phase (P=0.0001). In the most involved site, the PI and RI were undetectable in the inactive phase. The median PI was 1.4 in the mild phase, 1.3 in the moderate phase, and 1.1 in the severe phase (P=0.002). Conclusion. In contrast to the colon wall thickness, increased intramural blood flow reflected the clinical severity in ulcerative colitis patients.
Rare Earth Elements: Their Importance in Understanding Soil Genesis
Authors: Aide Michael T. , Aide Christine
Published: May 2012

The rare earth elements (REEs) are commonly defined as lanthanum (La) and the 14 elements comprising the Lanthanide series. The REE’s typically exhibit trivalent oxidation states; however, Europium may also occur as Eu2+ and Cerium may occur as Ce4+. The REE’s ionic radii decrease on progression from La to Lu, which results in a slight but predictable change in their chemical affinity. Typically, the light REE (La to Sm) reside in trace minerals such as apatite, epidote and allanite, whereas the heavy REE (Gd to Lu) are associated with minerals such as zircon. Investigations typically show that the REE are depleted in near-surface horizons and accumulate in deeper horizons or the regolith as clay-oxyhydroxide adsorbates or REE-phosphate precipitates. Numerous studies show the heavy REE accumulating in the deeper soil regions to a greater extent than the light REE, whereas other studies show the light REE’s preferentially accumulating at greater soil depths. The degree of interhorizon transport has great potential to become an index of weather intensity. The various REE soil migration pathways have been isolated, including lessivage, soil organic matter complexation, leaching in percolating water, adsorption by inorganic colloids, and precipitated by phosphate-bearing minerals.
Outcomes of Open Subacromial Decompression after Failed Arthroscopic Acromioplasty
Authors: Pillai Anand , Eranki Vivek , Malal Joby , Nimon Gavin
Published: May 2012

Aim. To prospectively assess the effectiveness of revision with open subacromial decompression in patients who had a previous unsatisfactory outcome with the arthroscopic procedure.Methods. 11 patients were identified for the study, who did not demonstrate expected improvement in symptoms after arthroscopic acromioplasty. All patients underwent structured rehabilitation. Functional evaluation was conducted using the Hospital for Special Surgery, New York, shoulder rating questionnaire.Results. M : F was 7 : 4. The mean age was 57 years. The average shoulder score improved from 49.6 preoperatively to 56 postoperatively at an average followup of 16 months. Two patients showed deterioration in their shoulder scores after revision while the rest showed only marginal improvement. All except one patient stated that they would opt for surgery again if given a second chance.Conclusion. In the group of patients that fail to benefit from the arthroscopic decompression, only a marginal improvement was noted after revision with open decompression.
Uso estratégico da internet e as mudanças de organizações do terceiro setor
Authors: Periotto Álvaro , Theodoro José
Published: May 2012

The sequence of transformations in chain that have marked the rhythm of development of oursociety finds in the Technology of the Information a new front, that quickly establishes changes in the form of theman to live and to become related. In this scene, the Internet discloses conditions realistic so that the Society of theKnowledge effectively stablishes yourself: the sites of the companies not only serve as points of attacked andelectronic retail, but become vital for electronic communications between the companies and its commercialemployees, customers, suppliers and partners; the governmental organizations invest to voluminous resources inthis technology, searching the control and the transparency of the public accounts and the installment of betterservices to the citizen; while that the organizations of the Third Sector search conditions more favorable topromote its causes and to reach effectiveness in its action. The job of the resources of the Internet and theconsequent redirectionment of efforts in the strategical management of the organizations of this last segment areplaced in the focus of queries in the present article.
A força das imagens na campanha civilista: representações em fotografias e caricaturas
Authors: Ueócka Lorayne Garcia
Published: May 2012

The presente has as objective the rescue of the construction of the image of Rui Barbosa as a mythpolitician through the production of caricatures and produced photographs about its respect in the First Republic.Our intention was to privilege as documentary source the iconographic material of rich value for the imaginaryunderstanding of the social one of the time.
Hiperatividade ou falta de limites?
Authors: Corredato Tania Regina , Brogio Silvana
Published: May 2012

The present work has an objective to understand the hiper-activity concept better, its mains symptomsand characteristics of the children who search psychological attendance with this complaint. For some authors, thehiper-activity concept is based on the construction of the medical thought, neurological illness, parallel to thecomment of the learning riots. The concepts of learning riots and hiper-activity had walked together in thescientific way, making it difficult the distinguishing diagnosis between both. The aspects of the diagnosis have beensubmitted to the numerous conceptualizations, redefinitions and renomeations, embracing and little enlightening.As well as the medical thought it is important for the hiper-activity diagnosis, other authors privilege the social andpsychological aspects.
A geografia no ensino fundamental - trajetória histórica e proposições pedagógicas
Authors: Gebran Raimunda Abou
Published: May 2012

In the present work we seek to trace the history of Geography as a school subject, trying tounderstand its configuration in different moments and contexts of the Brazilian educational politics, pointing outthe obstacles and the possibilities of overcoming this process. For such, we opt by a historical cutting implicatingthe last decades that presented significant changes in the educational politics and consequently in the trajectory ofthe different subjects
EDUCAÇÃO MORAL NA ESCOLA: CAMINHOS PARA A CONSTRUÇÃO DA CIDADANIA
Authors: Lepre Rita Melissa
Published: May 2012

The main purpose of this article is to reflect on moral education at school and its role in the construction of the citizen-student, in the search for the building of his autonomy. For such intent we present the conception of moral education proposed by some Spanish authors who continue and improve Piaget's ideas. Thereafter we propose an analysis of the school as a place for moral education focusing its possibilities and limitations.
A FORMAÇÃO DO LEITOR E O ENSINO DA LITERATURA
Authors: Bulhões Ricardo Magalhães
Published: May 2012

This is a report of an ongoing research. Theoretically its basic objective is to suggest certain connections between literature and education, verifying to what extension the traditional ways of expression are affected by the transforming power of language, also observing mechanical methodological alternatives, wick promote the lack of interest for literature texts.
JUVENTUDE DO CAMPO E POLÍTICAS PÚBLICAS: ALGUMAS REFLEXÕES DE UM TEXTO EM CONSTRUÇÃO
Authors: Silva Rogério Nunes da , Capelo Maria Regina Clivati
Published: May 2012

This article is result of a research work of a subgroup of research on Youths of rural areas of the Project "Catalogue of Youths: (Re) cognizing inequalities and diversities", which is being developed by an interdisciplinary group of professors and students of the State Unviersity of Londrina. The purpose of this paper is to map, even in a preliminary form, the several interpretations and concepts of present Brazilian rural areas. Another focus of our analysis intends to explain how modern sciences build the concept of youth as a social category and how this category can help us presently theorize about the rural area and the youth of rural areas. Finally we tried to identify which are the tensions faced by the youths of rural areas and how public policies are intervening in in this social segment.
O EDUCADOR MEDIADOR DO DISCENTE EM SUA FORMAÇÃO: A ARTE DO CUIDAR DO HUMANO
Authors: Cardoso Sônia Maria Vicente
Published: May 2012

This paper is a reflection about the significance of student-teacher relationship and its integration with the human care. Also, the text the role of education, that must be the obligation to prepare the students to behavior just like an individuals able to understanding themselves and all kind of people, performing their activities with respect and zealous in relation the people.
Immigrants, undocumented
Authors: Yamamoto Ryoko
Published: May 2012

Undocumented immigration refers to international migration without valid authorization from the government of the receiving country. In the contemporary nation‐state system, the cross‐national movement of people is controlled by national governments. Undocumented immigration is an international flow of people outside of the official governmental regulatory system. While undocumented migration includes both unauthorized emigration (exiting) and unauthorized immigration (entering and staying), public discussion almost exclusively focuses on the latter.
An adaptive robust observer for velocity estimation in an electro‐hydraulic system
Authors: Mohanty Amit , Gayaka Shreekant , Yao Bin
Published: May 2012

This paper proposes the design of an observer to estimate the velocity of an electro‐hydraulic system by using pressure measurements only. The difficulties involved in the design of an observer for such a system include the highly nonlinear system dynamics, severe parametric uncertainties such as large variation of inertial load and unmatched model uncertainties. In order to address these issues, a nonlinear model‐based adaptive robust observer is designed to estimate the velocity. The contributions of the proposed work is twofold. First, it introduces a novel coordinate transformation to reconstruct the velocity estimate. And second, from a structural viewpoint, the design has two important features: (i) an underlying robust filter structure, which can attenuate the effect of uncertain nonlinearities such as friction and disturbances on the velocity estimation, and (ii) an adaptation mechanism to reduce the extent of parametric uncertainties. Experimental results on the swing motion control of an electro‐hydraulic robot arm demonstrate the effectiveness of the proposed observer. Copyright © 2012 John Wiley & Sons, Ltd.
Strength, Hardening, and Failure Observed by In Situ TEM Tensile Testing
Authors: Kiener Daniel , Kaufmann Petra , Minor Andrew M.
Published: May 2012

We present in situ transmission electron microscope tensile tests on focused ion beam fabricated single and multiple slip oriented Cu tensile samples with thicknesses in the range of 100–200 nm. Both crystal orientations fail by localized shear. While failure occurs after a few percent plastic strain and limited hardening in the single slip case, the multiple slip samples exhibit extended homogenous deformation and necking due to the activation of multiple dislocation sources in conjunction with significant hardening. The hardening behavior at 1% plastic strain is even more pronounced compared to compression samples of the same orientation due to the absence of sample taper and the interface to the compression platen. Moreover, we show for the first time that the strain rate sensitivity of such FIB prepared samples is an order of magnitude higher than that of bulk Cu.
Nanostructuring Platinum Nanoparticles on Multilayered Graphene Petal Nanosheets for Electrochemical Biosensing
Authors: Claussen Jonathan C. , Kumar Anurag , Jaroch David B. , Khawaja M. Haseeb , Hibbard Allison B. , Porterfield D. Marshall , Fisher Timothy S.
Published: May 2012

Hybridization of nanoscale metals and carbon nanotubes into composite nanomaterials has produced some of the best‐performing sensors to date. The challenge remains to develop scalable nanofabrication methods that are amenable to the development of sensors with broad sensing ranges. A scalable nanostructured biosensor based on multilayered graphene petal nanosheets (MGPNs), Pt nanoparticles, and a biorecognition element (glucose oxidase) is presented. The combination of zero‐dimensional nanoparticles on a two‐dimensional support that is arrayed in the third dimension creates a sensor platform with exceptional characteristics. The versatility of the biosensor platform is demonstrated by altering biosensor performance (i.e., sensitivity, detection limit, and linear sensing range) through changing the size, density, and morphology of electrodeposited Pt nanoparticles on the MGPNs. This work enables a robust sensor design that demonstrates exceptional performance with enhanced glucose sensitivity (0.3 µM detection limit, 0.01–50 mM linear sensing range), a long stable shelf‐life (>1 month), and a high selectivity over electroactive, interfering species commonly found in human serum samples.
Biologically Responsive Polymeric Nanoparticles for Drug Delivery
Authors: Colson Yolonda L. , Grinstaff Mark W.
Published: May 2012

Responsive nanoparticles that release their drug cargo in accordance with a change in pH or oxidative stress are of significant clinical interest as this approach offers the opportunity to link drug delivery to a specific location or disease state. This research news article reviews the current state of this field by examining a series of published articles that highlight the novelty and benefits of using responsive polymeric particles to achieve functionally‐targeted drug delivery.
Update: An Efficient Synthesis of Poly(ethylene glycol)‐Supported Iron(II) Porphyrin Using a Click Reaction and its Application for the Catalytic Olefination of Aldehydes
Authors: Chinnusamy Tamilselvi , Rodionov Valentin , Kühn Fritz E. , Reiser Oliver
Published: May 2012

The facile synthesis of polyethylene glycol (PEG)‐immobilized iron(II) porphyrin using a copper‐catalyzed azide‐alkyne [3+2] cycloaddition “click” reaction is reported. The prepared complex 5 (PEG‐C51H39FeN7O) was found to be an efficient catalyst for the selective olefination of aldehydes with ethyl diazoacetate in the presence of triphenylphosphine, and afforded excellent olefin yields with high (E) selectivities. The PEG‐supported catalyst 5 was readily recovered by precipitation and filtration, and was recycled through ten runs without significant activity loss.
Efficient Procedures to Prepare Primary and Secondary Alkyl Halides from Alkanols via the Corresponding Sulfonates under Mild Conditions
Authors: Cahiez Gérard , Gager Olivier , Moyeux Alban , Delacroix Thomas
Published: May 2012

The study presented herein shows that sulfonate/halide exchange can be advantageously performed in THF to avoid several side reactions such as elimination and epimerization when the reaction is performed from a chiral alkyl sulfonate or a substrate having a CH acidic chiral center. The main limitation of this procedure was found to be the conversion of secondary alkyl sulfonates to alkyl chlorides. In this case, the addition of a catalytic amount of manganese chloride clearly accelerates the rate and the efficiency of the reaction.
A General Method for the Synthesis of 5H‐Benzo[b]‐, Carbazolo[2,3‐b]‐ and Indolo[2,3‐b]carbazole Derivatives via Copper(II) Triflate‐Catalyzed Heteroannulation
Authors: Prakash K. S. , Nagarajan Rajagopal
Published: May 2012

A straightforward approach for the construction of 5H‐benzo[b]‐, carbazolo[2,3‐b]‐ and indolo[2,3‐b]carbazole derivatives has been developed by using copper(II) triflate‐catalyzed heteroannulation.
Europium(III) Triflate‐Catalyzed Trofimov Synthesis of Polyfunctionalized Pyrroles
Authors: Madabhushi Sridhar , Vangipuram Venkata Sairam , Mallu Kishore Kumar Reddy , Chinthala Narsaiah , Beeram China Ramanaiah
Published: May 2012

The synthesis of polyfunctionalized pyrroles by reaction of a ketoxime with dimethyl acetylenedicarboxylate using europium(III) triflate as the catalyst is described.
Nanofiber‐Based Bulk‐Heterojunction Organic Solar Cells Using Coaxial Electrospinning
Authors: Bedford Nicholas M. , Dickerson Matthew B. , Drummy Lawrence F. , Koerner Hilmar , Singh Kristi M. , Vasudev Milana C. , Durstock Michael F. , Naik Rajesh R. , Steckl Andrew J.
Published: May 2012

Nanofibers consisting of the bulk heterojunction organic photovoltaic (BHJ–OPV) electron donor–electron acceptor pair poly(3‐hexylthiophene):phenyl‐C61‐butyric acid methyl ester (P3HT:PCBM) are produced through a coaxial electrospinning process. While P3HT:PCBM blends are not directly electrospinnable, P3HT:PCBM‐containing fibers are produced in a coaxial fashion by utilizing polycaprolactone (PCL) as an electrospinnable sheath material. Pure P3HT:PCBM fibers are easily obtained after electrospinning by selectively removing the PCL sheath with cyclopentanone (average diameter 120 ± 30 nm). These fibers are then incorporated into the active layer of a BHJ–OPV device, which results in improved short‐circuit current densities, fill factors, and power‐conversion efficiencies (PCE) as compared to thin‐film devices of identical chemical composition. The best‐performing fiber‐based devices exhibit a PCE of 4.0%, while the best thin‐film devices have a PCE of 3.2%. This increase in device performance is attributed to the increased in‐plane alignment of P3HT polymer chains on the nanoscale, caused by the electrospun fibers, which leads to increased optical absorption and subsequent exciton generation. This methodology for improving device performance of BHJ–OPVs could also be implemented for other electron donor–electron acceptor systems, as nanofiber formation is largely independent of the PV material.
Prothrombin complex concentrates in emergency bleeding disorders
Authors: Rodgers George M.
Published: May 2012

The use of prothrombin complex concentrates (PCCs), a heterogeneous combination of coagulation factors and counterbalancing inhibitor components, has broadened in recent years beyond single‐factor replacement in conditions such as hemophilia B, to encompass emergency reversal of anticoagulation secondary to oral vitamin K antagonists, ie, warfarin therapy. PCCs also have been studied in other bleeding disorders, such as surgery‐related and trauma‐related bleeding. This review provides an updated examination of the differences among PCC formulations, their potential role in the management of bleeding disorders, and the primary safety issues affecting their use. Am. J. Hematol. 2012. © 2012 Wiley Periodicals, Inc.
Meta‐analysis of genetic association studies on bipolar disorder
Authors: Seifuddin Fayaz , Mahon Pamela Belmonte , Judy Jennifer , Pirooznia Mehdi , Jancic Dubravka , Taylor Jacob , Goes Fernando S. , Potash James B. , Zandi Peter P.
Published: May 2012

Numerous candidate gene association studies of bipolar disorder (BP) have been carried out, but the results have been inconsistent. Individual studies are typically underpowered to detect associations with genes of small effect sizes. We conducted a meta‐analysis of published candidate gene studies to evaluate the cumulative evidence. We systematically searched for all published candidate gene association studies of BP. We then carried out a random‐effects meta‐analysis on all polymorphisms that were reported on by three or more case–control studies. The results from meta‐analyses of these genes were compared with the findings from a recent mega‐analysis of eleven genome‐wide association studies (GWAS) in BP performed by the Psychiatric GWAS Consortium (PGC). A total of 487 articles were included in our review. Among these, 33 polymorphisms in 18 genes were reported on by three or more case–control studies and included in the random‐effects meta‐analysis. Polymorphisms in BDNF, DRD4, DAOA, and TPH1, were found to be nominally significant with a P‐value < 0.05. However, none of the findings were significant after correction for multiple testing. Moreover, none of these polymorphisms were nominally significant in the PGC‐BP GWAS. A number of plausible candidate genes have been previously associated with BP. However, the lack of robust findings in our review of these candidate genes highlights the need for more atheoretical approaches to study the genetics of BP afforded by GWAS. The results of this meta‐analysis and from other on‐going genomic experiments in BP are available online at Metamoodics (http://metamoodics.igm.jhmi.edu). © 2012 Wiley Periodicals, Inc.
Loss of ERLIN2 function leads to juvenile primary lateral sclerosis
Authors: Al‐Saif Amr , Bohlega Saeed , Al‐Mohanna Futwan
Published: May 2012

Objective:

Primary lateral sclerosis (PLS) is a motor neuron disorder that exclusively affects upper motor neurons leading to their degeneration. Mutations in the ALS2 gene encoding the protein Alsin have been described previously in the juvenile form of the disease. In this study, we identify mutation of the ERLIN2 gene in juvenile PLS patients and describe an in vitro model for loss of ERLIN2 function.

Methods:

Single nucleotide polymorphism arrays were used for homozygosity mapping. DNA sequencing of candidate genes was used to detect the underlying mutation. Level of ERLIN2 mRNA was measured by quantitative real time polymerase chain reaction. Knocking down ERLIN2 in NSC34 cells was accomplished by short‐hairpin RNA interference.

Results:

We identified a splice junction mutation in the ERLIN2 gene—a component of the endoplasmic reticulum (ER) lipid rafts—that resulted in abnormal splicing of ERLIN2 transcript and nonsense‐mediated decay of ERLIN2 mRNA. Knocking down ERLIN2 in NSC34 cells suppressed their growth in culture.

Interpretation:

Recently, we found that mutation of SIGMAR1, a component of ER lipid rafts, leads to juvenile amyotrophic lateral sclerosis. The identification of mutation in another component of the ER lipid rafts in juvenile PLS patients emphasizes their role in motor neuron function. Furthermore, the discovered effect of ERLIN2 loss on cell growth may advance understanding of the mechanism behind motor neuron degeneration in PLS. ANN NEUROL 2012;72:510–516
Alzheimer disease family history impacts resting state functional connectivity
Authors: Wang Liang , Roe Catherine M. , Snyder Abraham Z. , Brier Matthew R. , Thomas Jewell B. , Xiong Chengjie , Benzinger Tammie L. , Morris John C. , Ances Beau M.
Published: May 2012

Objective:

Offspring whose parents have Alzheimer disease (AD) are at increased risk for developing dementia. Patients with AD typically exhibit disruptions in the default mode network (DMN). The aim of this study was to investigate the effect of a family history of late onset AD on DMN integrity in cognitively normal individuals. In particular, we determined whether a family history effect is detectable in apolipoprotein E (APOE) ε4 allele noncarriers.

Methods:

We studied a cohort of 348 cognitively normal participants with or without family history of late onset AD. DMN integrity was assessed by resting state functional connectivity magnetic resonance imaging.

Results:

A family history of late onset AD was associated with reduced resting state functional connectivity between particular nodes of the DMN, namely the posterior cingulate and medial temporal cortex. The observed functional connectivity reduction was not attributable to medial temporal structural atrophy. Importantly, we detected a family history effect on DMN functional connectivity in APOE ε4 allele noncarriers.

Interpretation:

Unknown genetic factors, embodied in a family history of late onset AD, may affect DMN integrity prior to cognitive impairment. ANN NEUROL 2012;72:571–577
Palladiumkatalysierte Kreuzkupplungen: eine historische Perspektive im Kontext der Nobel‐Preise 2010
Authors: Johansson Seechurn Carin C. C. , Kitching Matthew O. , Colacot Thomas J. , Snieckus Victor
Published: May 2012

Im Jahr 2010 wurden Richard Heck, Ei‐ichi Negishi und Akira Suzuki in den illustren Kreis der Chemie‐Nobelpreisträger aufgenommen. Begründet wurde diese Auszeichnung mit ihrer Rolle bei der Entdeckung und Entwicklung von praktischen Methoden zur C‐C‐Bindungsbildung. Ausgelöst durch ihre Beiträge über höchst nützliche palladiumkatalysierte Kreuzkupplungen, hat sich seit den frühen 1970er Jahren die Auswahl an verfügbaren Strategien und Methoden in der modernen organischen Synthese grundlegend verändert – sowohl für Chemiker an Hochschulen wie auch in der Industrie. Dieser Aufsatz vollzieht die historische Entwicklung dieser leistungsstarken Reaktionen nach: von den bahnbrechenden Entdeckungen bis hin zu den Kreuzkupplungsverfahren, die heute in der Synthese angewendet und hoch geschätzt werden.
Molekülverbände von Perylenbisimid‐Farbstoffen in Wasser
Authors: Görl Daniel , Zhang Xin , Würthner Frank
Published: May 2012

Perylenbisimide zählen zu den bedeutendsten funktionellen Farbstoffen mit vielfältigen Anwendungsmöglichkeiten. Aufgrund ihrer chemischen Robustheit, Photostabilität und herausragenden optischen und elektronischen Eigenschaften wurden sie als Pigmentfarbstoffe, Fluoreszenzsonden sowie n‐Halbleiter in der organischen Elektronik und Photovoltaik eingesetzt. Das ausgedehnte quadrupolare π‐System dieser Farbstoffklasse ermöglichte außerdem die Herstellung zahlreicher supramolekularer Architekturen mit faszinierenden photophysikalischen Eigenschaften. Jedoch blieb der supramolekulare Ansatz zur Bildung von Perylenbisimid‐Molekülverbänden größtenteils organischen Medien vorbehalten. Erfreulicherweise gab es in den letzten Jahren beachtliche Bemühungen zur Entwicklung von wasserlöslichen Perylenbisimiden und deren Anwendungen in wässrigen Medien. Dieser Aufsatz gibt einen aktuellen Überblick über die Selbstorganisation von Perylenbisimiden durch π‐π‐Wechselwirkung im wässrigen Medium. Synthetische Strategien zur Herstellung von wasserlöslichen Perylenbisimiden und der Einfluss des Wassers auf die π‐π‐Stapelung von Perylenbisimiden, sowie daraus resultierende Anwendungen werden eingehend diskutiert.
Palladium‐Catalyzed Cross‐Coupling: A Historical Contextual Perspective to the 2010 Nobel Prize
Authors: Johansson Seechurn Carin C. C. , Kitching Matthew O. , Colacot Thomas J. , Snieckus Victor
Published: May 2012

In 2010, Richard Heck, Ei‐ichi Negishi, and Akira Suzuki joined the prestigious circle of Nobel Laureate chemists for their roles in discovering and developing highly practical methodologies for CC bond construction. From their original contributions in the early 1970s the landscape of the strategies and methods of organic synthesis irreversibly changed for the modern chemist, both in academia and in industry. In this Review, we attempt to trace the historical origin of these powerful reactions, and outline the developments from the seminal discoveries leading to their eminent position as appreciated and applied today.
Molecular Assemblies of Perylene Bisimide Dyes in Water
Authors: Görl Daniel , Zhang Xin , Würthner Frank
Published: May 2012

Perylene bisimides are among the most valuable functional dyes and have numerous potential applications. As a result of their chemical robustness, photostability, and outstanding optical and electronic properties, these dyes have been applied as pigments, fluorescence sensors, and n‐semiconductors in organic electronics and photovoltaics. Moreover, the extended quadrupolar π system of this class of dyes has facilitated the construction of numerous supramolecular architectures with fascinating photophysical properties. However, the supramolecular approach to the formation of perylene bisimide aggregates has been restricted mostly to organic media. Pleasingly, considerable progress has been made in the last few years in developing water‐soluble perylene bisimides and their application in aqueous media. This Review provides an up‐to‐date overview on the self‐assembly of perylene bisimides through π–π interactions in aqueous media. Synthetic strategies for the preparation of water‐soluble perylene bisimides and the influence of water on the π–π stacking of perylene bisimides as well as the resulting applications are discussed.
Adsorption characteristics of tannic acid onto the novel protonated palygorskite/chitosan resin microspheres
Authors: Wu Jie , Chen Jing
Published: May 2012

Novel protonated palygorskite/chitosan resin microspheres (p‐PCRM) were prepared and applied as adsorbents for the removal of tannic acid (TA) from aqueous solution. The effects of palygorskite (PAL) content, the initial pH value of the TA solution, and contact time and temperature on adsorption capacity of the microspheres were investigated. The adsorption process was found to be pH dependant with an optimum activity at pH 8.0. In comparison with protonated chitosan microspheres (224 mg g−1), the p‐PCRM with 20 wt % PAL content exhibited higher adsorption capacity (455 mg g−1) for TA at the same adsorption conditions. This may be attributed to the hydrogen bonding between adsorbents and adsorbates, and the porous structure formed by the introduction of PAL, which were confirmed by Fourier transform infrared and the pore parameters analysis. The study of adsorption kinetics and isotherms showed that the sorption processes were better fitted by pseudo‐second‐order equation and the Langmuir equation, respectively. Furthermore, the desorption study implied that the p‐PCRM were recyclable when 0.1M HCl was used as eluents. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Effect of the sol fraction and hydrostatic deformation on the viscoelastic behavior of prestrained highly filled elastomers
Authors: Azoug A. , Constantinescu A. , Pradeilles‐Duval R. M. , Vallat M. F. , Nevière R. , Haidar B.
Published: May 2012

This study focuses on the relations between the microstructure and the viscoelastic behavior of an industrial solid propellant belonging to the class of highly filled elastomers. Precisely, the study aims at determining the impact on the viscoelastic behavior of the presence of the sol fraction inside the polymer network. The sol fraction is the part of the binder that a good solvent can extract. The solid propellant is swollen to various extents by solutions of plasticizer and polymer molecules. This swelling leads to a hydrostatic deformation of the polymer network, corresponding to an extension or contraction loading for each specimen. Prestrained dynamic mechanical analysis tests, superimposing a small oscillating strain on a prestrain, characterize the viscoelastic behavior. The degree of swelling of the network and the effective filler fraction drive the viscoelastic response. In addition, the mechanical behavior does not depend on the chemical nature of the introduced sol fraction. Moreover, a nonlinear behavior, i.e., an increase in both storage and loss moduli with increasing prestrain, is initiated at low prestrain. This nonlinearity depends on the contraction or extension of the network and could result from particles aligning with prestrain, which is expected in such highly filled materials. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Functionalization of polymer‐supported pentaerythritol as a general synthesis for the preparation of ion‐binding polymers
Authors: Alexandratos Spiro D. , Zhu Xiaoping
Published: May 2012

Pentaerythritol bonded to cross‐linked poly(vinylbenzyl chloride) beads (PE) provides a scaffold onto which ligands can be attached by reaction with reactive compounds such as phosphoryl halides. To broaden the applicability of PE for the preparation of ion‐selective polymers, conditions are reported for the conversion of the hydroxyl group to the bromide, which acts as a better leaving group. The CH2Br moiety thus provides a handle on which an array of ligands can be bound through nucleophilic substitution. In this first in a series of reports, immobilization of diethylamine onto the PE and the ion‐binding affinities of the resulting polymer are described. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis of crosslinkable fluorinated linear‐hyperbranched copolyimides for optical waveguide devices
Authors: Liu Yu , Yao Hongyan , Zhang Yunhe , Zhang Haibo , Mu Jianxin , Jiang Zhenhua , Guan Shaowei
Published: May 2012

A series of novel crosslinkable fluorinated linear‐hyperbranched copolyimides (co‐FHBPIs) were prepared by condensation of 1,3,5‐tris(2‐trifluoromethy‐4‐aminopheoxy) benzene (TFAPOB), 1,4‐bis(4‐amino‐2‐trifluoromethylphenoxy) benzene (6FAPB), and 4,4′‐(2‐(3′,5′‐ditrifluoromethylphenyl)‐1,4‐phenylenedioxy)‐diphthalic anhydride (6FPDA) with different feed ratio, which followed by reaction with 3‐ethynylaniline. Under this circumstance, as the TFAPOB/6FAPB ratio increases, the Tg of the polymers decreases gradually from 218 to 199°C, and the Young's moduli decreases from 2.14 to 1.64 GPa. Although, the refractive indices are adjustable in the ranges of 1.5755–1.5631, and the polymer birefringences decrease from 0.0122 to 0.0012 at wave length 650 nm. The polymer films were fabricated by spin‐coating and crosslinked by thermal curing. The cured films have good resistance to common organic solvents such as acetone, tetrahydrofuran, N, N‐dimethylformamide, dimethyl sulfoxide, and chloroform. The glass transition temperature of E‐coFHBPI 50 (the TFAPOB/(6FAPB+ TFAPOB) ratio is 50%)changes from 200 to 243°C after curing, which shows higher thermal stability up to 582°C (5% weight loss). Rib‐type optical waveguide device is fabricated by E‐coFHBPI 50, which demonstrates an obvious near‐field mode pattern of the waveguide. All the results indicated that the polymers are promising candidates for optical waveguide materials. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
The physical properties of nonionic waterborne polyurethane with a polyether as side chain
Authors: Li Bing , Peng Dan , Zhao Ning , Mu Qiuhong , Li Jinhui
Published: May 2012

A series of nonionic waterborne polyurethanes (WPU) based on hydrogenated methylene diphenylene diisocyanate, polybutylene succinate diol, polybutylene adipate diol, polyethylene glycol, and diethylene glycol as chain extender were synthesized with a polyether, MPEG‐(OH)2, as side chain. The physical properties such as tensile strength, elongation, hardness, molecular weight, kinetic viscosity, and so on were detected. The WPUs made with polyesters have the best tensile strength but the lowest elongation. Because of the hydrophilic property of MPEG‐(OH)2 grafted on the WPUs, they have obvious increases of solid contents and water absorptions with the ratio of MPEG‐(OH)2. The functional group ratio of NCO/OH is another reason affecting the hydrophilic properties of the WPUs. In addition, the water ratios of the dispersions dramatically affect the stability of WPU systems. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013