bluuebunny/crossref_metadata_2025 huggingface dataset:
Social environment affects the transcriptomic response to bacteria in ant queens
Authors: Viljakainen Lumi , Jurvansuu Jaana , Holmberg Ida , Pamminger Tobias , Erler Silvio , Cremer Sylvia
Published: October 2018

Social insects have evolved enormous capacities to collectively build nests and defend their colonies against both predators and pathogens. The latter is achieved by a combination of individual immune responses and sophisticated collective behavioral and organizational disease defenses, that is, social immunity. We investigated how the presence or absence of these social defense lines affects individual‐level immunity in ant queens after bacterial infection. To this end, we injected queens of the ant Linepithema humile with a mix of gram+ and gram− bacteria or a control solution, reared them either with workers or alone and analyzed their gene expression patterns at 2, 4, 8, and 12 hr post‐injection, using RNA‐seq. This allowed us to test for the effect of bacterial infection, social context, as well as the interaction between the two over the course of infection and raising of an immune response. We found that social isolation per se affected queen gene expression for metabolism genes, but not for immune genes. When infected, queens reared with and without workers up‐regulated similar numbers of innate immune genes revealing activation of Toll and Imd signaling pathways and melanization. Interestingly, however, they mostly regulated different genes along the pathways and showed a different pattern of overall gene up‐regulation or down‐regulation. Hence, we can conclude that the absence of workers does not compromise the onset of an individual immune response by the queens, but that the social environment impacts the route of the individual innate immune responses.
Disturbance shapes avian communities on a grassland–sagebrush ecotone
Authors: Duchardt Courtney J. , Porensky Lauren M. , Augustine David J. , Beck Jeffrey L.
Published: October 2018

Ecotones, or transitional zones between ecosystems, are often hotspots for biodiversity and targets for conservation. Where the Great Plains meet the sagebrush (Artemisiaspp.) steppe, an opportunity exists to conserve habitat for the two most imperiled avian guilds in North America, grassland and shrub‐steppe birds. This ecotone creates a unique challenge with respect to the management of disturbance processes, such as fire and grazing, because grassland and sagebrush‐shrubland birds respond quite dissimilarly to disturbance. To address this management challenge and maximize conservation opportunities, we examined the responses of grassland and sagebrush bird communities to disturbance at a grassland–sagebrush ecotone in northeast Wyoming,USA. Specifically, we surveyed bird communities on active black‐tailed prairie dog (Cynomys ludovicianus) colonies and burned areas, as well as on paired undisturbed points in 2016 and 2017. Bird community structure varied in response to both the presence and type of disturbance. Although alpha diversity of avian species was highest on undisturbed sites and burned areas, only prairie dog colonies provided breeding habitat for the imperiled shortgrass‐obligate mountain plover (Charadrius montanus), and species turnover (beta diversity) was greatest between on‐colony and off‐colony points. Furthermore, bird communities were shaped by both disturbance‐dependent (e.g., disturbance age) and disturbance‐independent (e.g., topography and soils) landscape features. Managers must balance the benefits of high species diversity in undisturbed sagebrush with habitat requirements of other imperiled species like the mountain plover. This may entail prioritizing the amount and distribution of disturbances in relation to population goals for species of conservation concern while simultaneously maintaining a mosaic of all three patch types in this landscape.
Energy Production and Storage Promoted by Organometallic Complexes
Authors: Bellini Marco , Bevilacqua Manuela , Marchionni Andrea , Miller Hamish Andrew , Filippi Jonathan , Grützmacher Hansjörg , Vizza Francesco
Published: October 2018

Invited for the cover of this issue are the groups of Hansjörg Grützmacher at ETH, Zürich, Switzerland, and Francesco Vizza at ICCOM‐CNR in Florence, Italy. The cover image shows a single courageous fish swimming against the main school of fish. This fish represents the few examples of organometallic electrocatalysts that have been successfully used in a fuel cell or in an electrolyzer.
A β‐Diketiminato‐Based Pincer‐Type Nickel(II) Complex: Synthesis and Catalytic Performance in the Cross‐Coupling of Aryl Fluorides with Aryl Grignard Reagents
Authors: Kurisu Nobutaka , Asano Erika , Hatayama Yuki , Kurihara Youji , Hashimoto Toru , Funatsu Kei , Ueda Kazuyoshi , Yamaguchi Yoshitaka
Published: October 2018

A β‐diketiminato‐based tridentate pincer‐type nickel(II) complex Ni‐NNP was prepared by the reaction of the nickel(II) precursor [NiCl2(2,4‐lutidine)2] with the lithiated NNP ligand, which was generated in situ by the reaction of the NNP pro‐ligand H‐NNP with nBuLi. H‐NNP was prepared by the condensation of 4‐[(2,4,6‐trimethylphenyl)amino]pent‐3‐en‐2‐one with 2‐(diphenylphosphanyl)ethylamine. Ni‐NNP was characterized spectroscopically and by X‐ray diffraction, revealing a slightly distorted square‐planar geometry around the nickel center. Density functional theory calculations indicated that the highest occupied molecular orbital in Ni‐NNP is located at higher energy than those of three other homologous nickel(II) complexes, i.e., Ni‐ONN, Ni‐ONP, and Ni‐NNN, which contain β‐aminoketonato‐ or β‐diketiminato‐based pincer‐type ligands. The electronic and steric properties of Ni‐NNP effectively facilitated the cross‐coupling of aryl fluorides with aryl Grignard reagents.
DMSO tolerant NAD(P)H recycler enzyme from a pathogenic bacterium, Burkholderia dolosa PC543: effect of N‐/C‐terminal His Tag extension on protein solubility and activity
Authors: Alpdağtaş Saadet , Çelik Ayhan , Ertan Fatma , Binay Barış
Published: October 2018

NAD(P)+ dependent formate dehydrogenase (FDH) is an oxidoreductase used as a biocatalyst to regenerate NAD(P)H in reductase‐mediated chiral synthesis reactions. Solvent stability and the need to reduce NADP+ to NADPH, due to the high cost of NADPH, are required features in the industrial usage of FDHs. Therefore, we aimed to identify a novel, robust NADP+ dependent FDH and evaluate the effect of N‐ and C‐ terminus His tag extensions on protein solubility and activity. Herein, we report a novel, DMSO tolerant formate dehydrogenase (BdFDH), which has dual coenzyme specificity and tolerance to acidic pH, from Burkholderia dolosa PC543. N‐ and C‐terminus His‐tagged BdFDHs were expressed separately in Escherichia coli BL21 (DE3). The C‐terminal His‐tagged BdFDH was soluble and active whereas the N‐terminal version was not. The enzyme displays dual coenzyme specificity and resistance to some organic solvents, particularly DMSO, and is able to tolerate acidic pH conditions. The apparent KM values for NADP+, NAD+ and sodium formate (with NADP+), are 1.17, 14.7 and 5.66 mM, respectively. As a result, due to its DMSO tolerance and coenzyme preference, this enzyme can be utilized as an NAD(P)H recycler in several biotransformations particularly when carried out under acidic conditions. Moreover, it can be said that the position of the His tag extension may affect the enzyme solubility and functionality.
Evaluation of U. S. National Toxicology Program (NTP) mouse lymphoma assay data using International Workshop on Genotoxicity Tests (IWGT) and the Organization for Economic Co‐Operation and Development (OECD) criteria
Authors: Schisler M. R. , Gollapudi B. B. , Moore M. M.
Published: October 2018

The forward gene mutation mouse lymphoma assay (MLA) is widely used, as part of a regulatory test battery, to identify the genotoxic potential of chemicals. It identifies mutagens capable of inducing a variety of genetic events. During the 1980s and early 1990s, the U.S. National Toxicology Program (NTP) developed a publicly available database (https://tools.niehs.nih.gov/cebs3/ui/) of MLA results. This database is used to define the mutagenic potential of chemicals, to develop structure–activity relationships (SAR), and to draw correlations to animal carcinogenicity findings. New criteria for MLA conduct and data interpretation were subsequently developed by the International Workshop for Genotoxicity Testing (IWGT) and the Organization of Economic Cooperation and Development (OECD). These recommendations are included in a new OECD Test Guideline (TG490). It is essential that early experimental data be re‐examined and classified according to the current criteria to build a curated database to better inform chemical‐specific evaluations and SAR models. We re‐evaluated more than 1900 experiments representing 342 chemicals against the newly defined acceptance criteria for background mutant frequency (MF), cloning efficiency (CE), positive control values (modified for this evaluation due to lack of colony sizing), appropriate dose selection, and data consistency. Only 17% of the evaluated experiments met all acceptance criteria used in this re‐evaluation. Results from 211 chemicals were determined to be uninterpretable, 92 were positive, and 39 equivocal. The authors could not classify any responses as negative because colony sizing was not performed for any of these experiments and it is clear, based on many experiment with unacceptably low background and positive control MFs, that mutant colony recovery was often suboptimal. This re‐evaluation provides a curated database for the MLA. A similar curation should be done for other widely used genetic toxicology assays, but will be more difficult for certain assays (e.g., in vitro chromosomal aberrations) because important parameters such as level of cytotoxicity were often not evaluated/reported. Environ. Mol. Mutagen. 59:829–841, 2018. © 2018 Wiley Periodicals, Inc.
The Effect of Transition Alumina (γ‐, η‐, χ‐Al2O3) on the Activity and Stability of Chromia/Alumina Catalysts. Part I: Model Catalysts and Aging Conditions
Authors: Nazimov Daniil A. , Klimov Oleg V. , Trukhan Sergey N. , Cherepanova Svetlana V. , Prosvirin Igor P. , Noskov Aleksandr S.
Published: October 2018

The effect of transition alumina (γ‐, η‐, χ‐Al2O3) on the activity and stability of model chromia/alumina catalysts with 4 wt% Cr in isobutane dehydrogenation is studied. It is shown that a fresh catalyst with η‐Al2O3as a support has the highest activity, while with χ‐Al2O3has the lowest one. The characterization of the catalysts by N2adsorption, X‐ray diffraction (XRD), electron spin resonance (ESR) spectroscopy, and X‐ray photoelectron spectroscopy (XPS) is used to describe changes in the catalysts induced by high‐temperature treatment at 800, 1000, and 1200 °C in air. It is shown that sintering of the alumina support and formation of chromia‐alumina solid solutions are the reasons of irreversible decline in the catalytic activity. Cr/γ‐Al2O3is found to be the most stable to sintering and phase transformation, whereas Cr/χ‐Al2O3is found to be the least stable. Due to its highest initial activity, the η‐Al2O3‐supported catalyst loses its dehydrogenation activity most rapidly as the calcination temperature is raised. The segregation of sodium impurities is observed in the course of heat treatment, which may be an additional cause of deactivation.
The Effect of Transition Alumina (γ‐, η‐, χ‐Al2O3) on the Activity and Stability of Chromia/Alumina Catalysts. Part II: Industrial‐Like Catalysts and Real Plant Aging Conditions
Authors: Nazimov Daniil A. , Klimov Oleg V. , Shaverina Anastasiya V. , Cherepanova Svetlana V. , Larina Tatyana V. , Khabibulin Dzhalil F. , Noskov Aleksandr S.
Published: October 2018

The effect of alumina structure (γ‐, η‐, χ‐Al2O3) on the long‐term stability of industrial‐like Cr2O3/Al2O3dehydrogenation catalysts under industrial dehydrogenation conditions is studied. It is shown that the type of alumina support determines physicochemical and catalytic stability of the catalyst: η‐Al2O3is the most stable against irreversible deactivation, whereas χ‐Al2O3is the least stable. One of the possible reasons of predominant stability of η‐Al2O3‐based catalyst is its relatively high sintering stability under real plant conditions. High‐temperature (>800 °C) calcination, sometimes used to compare stabilities of chromia/alumina catalysts, appears to be unable to simulate industrial aging because of the inconsistency of the phase composition of industrially and artificially aged catalysts.
Individual and simultaneous adsorption of Ni (II), Cd (II), and Zn (II) ions over polyamide resin: Equilibrium, kinetic and thermodynamic studies
Authors: Thangaraj Vidhyadevi , Aravamudan Kannan , Lingam Ravikumar , Subramanian Sivanesan
Published: October 2018

Heavy metal pollution is a serious environmental issue worldwide with rapid increase in global industrial activities (Podder and Majumder [2016]: Water Conserv Sci Eng 1, 103–125). In this study, aromatic polyamide (PA) containing the azomethine group (Vidhyadevi et al. [2012]: Sep Sci Technol 48, 1450–1458) was used as an adsorbent for the individual and simultaneous adsorption of Ni (II), Cd (II), and Zn (II) ions from their aqueous solutions. Equilibrium, kinetic, and thermodynamic analyses of Ni (II), Cd (II), and Zn (II) ions adsorption were also carried out. The kinetic study on heavy metal ions adsorption suggests that the adsorption follows pseudo‐second‐order kinetic model. The thermodynamic study results revealed that the process is spontaneous and exothermic in nature. In the multicomponent adsorption system, adsorption of one metal ion was considerably reduced by the presence of other ions in the solution due to competition for the active sites on PA. The adsorption of heavy metal ions over PA was confirmed through FT‐IR, SEM, and EDX analyses. The adsorption capacity of PA was found significantly higher than other adsorbents. The PA could be regenerated and reused even after five cycles for the Ni (II), Cd (II), and Zn (II) ions suggesting that adsorption using the PA is a reversible process.

Significance of the present work

Polyamide resin (PA) is an effective adsorbent for the individual and simultaneous removal of Ni (II), Cd (II), and Zn (II).

Maximum adsorption capacity of PA for Ni (II), Cd (II), and Zn (II) ions were found to be better than other commonly used adsorbents.

Repeated desorption studies indicate that the PA may be reused and the adsorption is a reversible process.

Adsorption mechanism of metal ions over PA is explained.

© 2018 American Institute of Chemical Engineers Environ Prog, 38: S340–S351, 2019
An International Perspective on the Tools and Concepts for Effluent Toxicity Assessments in the Context of Animal Alternatives: Reduction in Vertebrate Use
Authors: Norberg-King Teresa J. , Embry Michelle R. , Belanger Scott E. , Braunbeck Thomas , Butler Joshua D. , Dorn Phil B. , Farr Brianna , Guiney Patrick D. , Hughes Sarah A. , Jeffries Marlo , Journel Romain , Lèonard Marc , McMaster Mark , Oris James T. , Ryder Kathy , Segner Helmut , Senac Thomas , Van Der Kraak Glen , Whale Graham , Wilson Peter
Published: October 2018

Since the 1940s, effluent toxicity testing has been used to assess potential ecological impacts of effluents and help determine necessary treatment options for environmental protection prior to release. Strategic combinations of toxicity tests, analytical tools, and biological monitoring have been developed. Because the number of vertebrates utilized in effluent testing is thought to be much greater than that used for individual chemical testing, there is a new need to develop strategies to reduce the numbers of vertebrates (i.e., fish) used. This need will become more critical as developing nations begin to use vertebrates in toxicity tests to assess effluent quality. A workshop was held to 1) assess the state of science in effluent toxicity testing globally; 2) determine current practices of regulators, industry, private laboratories, and academia; and 3) explore alternatives to vertebrate (fish) testing options and the inclusion of modified/new methods and approaches in the regulatory environment. No single approach was identified, because of a range of factors including regulatory concerns, validity criteria, and wider acceptability of alternatives. However, a suite of strategies in a weight-of-evidence approach would provide the flexibility to meet the needs of the environment, regulators, and the regulated community; and this “toolbox” approach would also support reduced reliance on in vivo fish tests. The present Focus article provides a brief overview of wastewater regulation and effluent testing approaches. Alternative methodologies under development and some of the limitations and barriers to regulatory approaches that can be selected to suit individual country and regional requirements are described and discussed. Environ Toxicol Chem 2018;37:2745–2757. © 2018 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.
Effects of neonicotinoids on putative escape behavior of juvenile wood frogs (Lithobates sylvaticus) chronically exposed as tadpoles
Authors: Lee-Jenkins Stacey S.Y. , Robinson Stacey A.
Published: October 2018

Neonicotinoids are water-soluble neurotoxic insecticides widely used in agriculture that are being detected in nontarget aquatic environments. Nontarget aquatic wildlife, such as amphibians, may be at risk of exposure. Studies using larval stages suggest neonicotinoids are a minor concern to amphibians; however, behavioral effects manifesting later in life are not often considered. Behavioral endpoints could further our understanding of potential sublethal neurotoxic effects after exposure has ended. Using juvenile wood frogs (Lithobates sylvaticus), we investigated the effects of chronic larval exposure to 3 concentrations (1, 10, and 100 μg/L) of formulations containing imidacloprid or thiamethoxam on the putative escape response to a simulated heron attack. We found that control frogs actively responded (i.e., moved or jumped) to the simulated predator attack but frogs exposed to imidacloprid at 10 and 100 μg/L were less likely to respond. The exposed frogs, specifically from the imidacloprid treatment at 10 μg/L (tendency at 100 μg/L) were less likely to leave the attack area compared with controls. However, frogs used refuge similarly among all treatments. Finally, there were no differences in locomotor performance, as measured by total number of jumps and distance traveled during a trial among treatments. In conclusion, our study suggests that exposure to neonicotinoids during amphibian larval development may affect a juvenile frog's ability to perceive or respond to a predator, potentially increasing their vulnerability to predation. Future studies should validate and explore this potential effect further. Environ Toxicol Chem 2018;37:3115–3123. © 2018 Crown in the right of Canada. Published by Wiley Periodicals Inc. on behalf of SETAC.
Effective Utilization of Waste Red Mud for High Performance Supercapacitor Electrodes
Authors: Bhattacharya Gourav , Fishlock Sam Jeffery , Roy Joy Sankar , Pritam Anurag , Banerjee Debosmita , Deshmukh Sujit , Ghosh Subhasis , McLaughlin James A. , Roy Susanta Sinha
Published: October 2018

In recent years, metal oxide‐based, inexpensive, stable electrodes are being explored as a potent source of high performance, sustainable supercapacitors. Here, the employment of industrial waste red mud as a pseudocapacitive electrode material is reported. Mechanical milling is used to produce uniform red mud nanoparticles, which are rich in hematite (Fe2O3), and lower amounts of other metal oxides. A comprehensive supercapacitive study of the electrode is presented as a function of ball‐milling time up to 15 h. Ten‐hour ball‐milled samples exhibit the highest pseudocapacitive behavior with a specific capacitance value of ≈317 F g−1, at a scan rate of 10 mV s−1 in 6 m aqueous potassium hydroxide electrolyte solution. The modified electrode shows an extraordinary retention of ≈97% after 5000 cycles. A detailed quantitative electrochemical analysis is carried out to understand the charge storage mechanism at the electrode–electrolyte interface. The formation of uniform nanoparticles and increased electrode stability are correlated with the high performance. This work presents two significant benefits for the environment; in energy storage, it shows the production of a stable and efficient supercapacitor electrode, and in waste management with new applications for the treatment of red mud.
PI3K: A master regulator of brain metastasis‐promoting macrophages/microglia
Authors: Blazquez Raquel , Wlochowitz Darius , Wolff Alexander , Seitz Stefanie , Wachter Astrid , Perera‐Bel Julia , Bleckmann Annalen , Beißbarth Tim , Salinas Gabriela , Riemenschneider Markus J. , Proescholdt Martin , Evert Matthias , Utpatel Kirsten , Siam Laila , Schatlo Bawarjan , Balkenhol Marko , Stadelmann Christine , Schildhaus Hans‐Ulrich , Korf Ulrike , Reinz Eileen , Wiemann Stefan , Vollmer Elena , Schulz Mathias , Ritter Uwe , Hanisch Uwe K. , Pukrop Tobias
Published: October 2018

Mutations and activation of the PI3K signaling pathway in breast cancer cells have been linked to brain metastases. However, here we describe that in some breast cancer brain metastases samples the protein expression of PI3K signaling components is restricted to the metastatic microenvironment. In contrast to the therapeutic effects of PI3K inhibition on the breast cancer cells, the reaction of the brain microenvironment is less understood. Therefore we aimed to quantify the PI3K pathway activity in breast cancer brain metastasis and investigate the effects of PI3K inhibition on the central nervous system (CNS) microenvironment. First, to systematically quantify the PI3K pathway activity in breast cancer brain metastases, we performed a prospective biomarker study using a reverse phase protein array (RPPA). The majority, namely 30 out of 48 (62.5%) brain metastatic tissues examined, revealed high PI3K signaling activity that was associated with a median overall survival (OS) of 9.41 months, while that of patients, whose brain metastases showed only moderate or low PI3K activity, amounted to only 1.93 and 6.71 months, respectively. Second, we identified PI3K as a master regulator of metastasis‐promoting macrophages/microglia during CNS colonization; and treatment with buparlisib (BKM120), a pan‐PI3K Class I inhibitor with a good blood‐brain‐barrier penetrance, reduced their metastasis‐promoting features. In conclusion, PI3K signaling is active in the majority of breast cancer brain metastases. Since PI3K inhibition does not only affect the metastatic cells but also re‐educates the metastasis‐promoting macrophages/microglia, PI3K inhibition may hold considerable promise in the treatment of brain metastasis and the respective microenvironment.
Does financial market growth improve income distribution? A comparison of developed and emerging market economies of the global sample
Authors: Paramati Sudharshan Reddy , Nguyen Thanh Pham Thien
Published: October 2018

The objective of this research is to investigate the effects of stock market indicators, banking, and foreign direct investment inflows on income inequalities in developed and emerging market economies around the world. For this reason, the study utilizes annual data that range from 1981 to 2014 on the selected indicators. Given the nature of our variables, we employ panel autoregressive distributed lag models to explore the long‐run estimates of income inequalities. The long‐run estimates indicate that the stock market indicators have significant positive and negative impact on income inequalities in developed and emerging market economies, respectively. Further, our findings show that the banking credit adversely affects income inequalities both in developed and emerging economies. Our results also establish significant short‐run causalities among stock market indicators and income inequalities. Given these findings, we argue that the stock markets are playing an important role in reducing income inequalities in emerging economies whereas they contribute for higher inequalities in developed economies.
Is Instructional Scaffolding Actually Vygotskian, and Why Should It Matter to Literacy Teachers?
Authors: Smagorinsky Peter
Published: October 2018

In this commentary, the author reconceives Vygotsky's zone of proximal development (ZPD), particularly its conflation with the notion of instructional scaffolding. The author reviews Vygotsky's description of theZPDand how it has come to be misinterpreted; summarizes Wood, Bruner, and Ross's introduction of the scaffolding metaphor and how it emerges from a poor translation; and provides a different, more accurate translation of theZPDas the zone of next development as available in the documentary filmThe Butterflies of Zagorsk. The author argues that the conflation of scaffolding with theZPDhas produced a trivialization of Vygotsky's greater body of work, which focused on long‐term, socially mediated human development not short‐term learning. The author makes a case for contextualizing Vygotsky's attention to theZPD(better translated as zone of next development) in a broader reading of his work and its emphasis on how people develop over time rather than through brief pedagogical intervention.
This Is What We Came Here to Do: Literacy at the Heart of Institutional Culture Change
Authors: Hogan Nika , Rose Shelagh
Published: October 2018

This department focuses on literacy leaders, including school and instructional leaders, teachers, and external partners, who are working to improve outcomes for adolescent and adult learners in a wide range of education settings. Columns investigate the challenges and complexities inherent in such work and share lessons learned, impactful strategies and approaches, and promising pathways forward.
Reading and Writing on Screen and Paper
Authors: Fisher Douglas , Frey Nancy
Published: October 2018

This forum highlights research that literacy teachers, students, and others can explore, use, or adapt as they provide literacy instruction and develop related programs and research agendas.
Boundary Crossings at the Intersection of Texts and Identities
Authors: Holmes Tamie R.
Published: October 2018

This forum focuses on the intersections of texts and identities with the aim of selecting and mediating texts that readers and writers find valuable within and outside of formal educational settings.
Acquisition and generative responding following print‐to‐braille construction response training with sighted learners
Authors: Lillie Madelynn A. , Tiger Jeffrey H.
Published: October 2018

Previous researchers have taught sighted adults to match braille sample stimuli to print comparisons in a matching‐to‐sample (MTS) format and assessed the emergence of other braille repertoires, such as transcribing and reading braille following this training. Although participants learned to match to sample with braille, they displayed limited emergence of other braille repertoires. Lack of generative responding may have resulted from participants' over‐selective attending to components of compound braille characters during instruction. We taught undergraduates to construct braille characters given a print sample, which required attending to each individual braille symbol, and assessed generative braille responding. Participants met mastery of 378 braille construction responses and demonstrated modestly improved responding compared with previous research.
Particle‐coated electrospun scaffold: A semi‐conductive drug eluted scaffold with layered fiber/particle arrangement
Authors: Khorshidi Sajedeh , Karkhaneh Akbar
Published: October 2018

In this study, an antibacterial fiber/particle scaffold with improved hydrophilicity has been fabricated. To this end, polyaniline (PANi)/polycaprolactone (PCL) was processed to fibers via electrospinning. Thereafter, ciprofloxacin was loaded in oxidized alginate/gelatin mixture. The mixture was then electrosprayed onto PANi‐based fibers. After particle solidification, oxidized alginate and gelatin simultaneously were crosslinked and encapsulated the ciprofloxacin. The particle/fiber scaffold enabled controlled release of ciprofloxacin. Moreover, the scaffold offered a semi‐conductive structure in which the conductive fibers were interrupted by insulating particles. The scaffold proved higher hydrophilicity, better cell adhesion and proliferation compared with the pristine fibers. Furthermore, the scaffold demonstrated extensive antibacterial activity against gram positive and gram negative bacteria tested. The construct with layered fiber/particle arrangement and benefited from electrical semi‐conductivity, relevant surface hydrophilicity and controlled release of an antibacterial component can be a potent nerve tissue engineering scaffold. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 3248–3254, 2018.
Comparison of visible and UVA phototoxicity in neural culture systems micropatterned with digital projection photolithography
Authors: Khoshakhlagh Parastoo , Bowser Devon A. , Brown J. Quincy , Moore Michael J.
Published: October 2018

Photopolymerization provides a favorable method for hydrogel formation due to its simplicity, convenience, and versatility. However, the light exposure required to initiate photopolymerization is known to have a cytotoxic effect on encapsulated cells. Here, a 3D in vitro model of the nervous system microenvironment, micropatterned through the use of digital projection photolithography using a single hydrogel formulation that cross‐links similarly under ultraviolet A (UVA, 315–400 nm) and visible light (400–700 nm) exposure, is presented. This setup allowed for the investigation of neuronal responses to different light wavelengths and exposure times during photoencapsulation, while ruling out effects due to the hydrogel formulation or photoinitiators used. Cellular studies—including neurite viability, DNA fragmentation, and neurite outgrowth for both UVA and visible light irradiation, the most common spectra used in biological photomicropatterning applications—were performed to assess the effect of light source on neuronal cultures. These studies indicated that while cell death occurs after exposure to either spectrum, visible light was less phototoxic than UVA, when using comparable levels of irradiation, and interestingly, glial cells were more susceptible to phototoxicity than neuronal cells. Thus, while utilizing visible light for micropatterning and cell encapsulation for nervous system applications is beneficial, it is helpful to keep the light exposure low to ensure optimal neuronal survival and growth. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 134–144, 2019.
Matrices based on lineal and star fumarate‐metha/acrylate copolymers for bone tissue engineering: Characterization and biocompatibility studies
Authors: Bravi Costantino M. Leticia , Oberti Tamara G , Cortizo Ana M. , Cortizo M. Susana
Published: October 2018

This article presents the preparation of matrices from two new families of fumaric copolymers and the effect of structural differences on their physicochemical and biological behavior. Diisopropyl fumarate (DIPF) and poly(ethylene glycol) methyl ether methacrylate (OEGMA) or N‐isopropylacrylamide (NIPAM) were copolymerized by conventional radical and RAFT polymerization to obtain lineal or start architectures, respectively. These copolymers were characterized by spectroscopic (FTIR and 1H‐NMR) and chromatographic methods. The thermal stability was studied by thermal gravimetric analysis, showing some differences in relation to the architecture and chemical nature of copolymers. SEM morphological analysis demonstrated that the surface of the matrices derived from OEGMA exhibited an irregular and rough surface, while DIPF–NIPAM copolymers presented smooth surface with nearly no significant porosity. The matrix obtained of both kinds of copolymers presented no cytotoxicity as it was evaluated using a model of macrophages on culture. Moreover, cell growth was better on the surfaces of the DIPF–NIPAM matrices, suggesting a good interaction with this matrix and its potential application as matrices for tissue engineering. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 195–203, 2019.
Ultrashort echo time imaging for quantification of hepatic iron overload: Comparison of acquisition and fitting methods via simulations, phantoms, and in vivo data
Authors: Tipirneni‐Sajja Aaryani , Loeffler Ralf B. , Krafft Axel J. , Sajewski Andrea N. , Ogg Robert J. , Hankins Jane S. , Hillenbrand Claudia M.
Published: October 2018

Background

Current R2*‐MRI techniques for measuring hepatic iron content (HIC) use various acquisition types and fitting models.

Purpose

To evaluate the accuracy and precision of R2*‐HIC acquisition and fitting methods.

Study Type

Signal simulations, phantom study, and prospective in vivo cohort.

Population

In all, 132 patients (58/74 male/female, mean age 17.7 years).

Field Strength/Sequence

2D‐multiecho gradient‐echo (GRE) and ultrashort echo time (UTE) acquisitions at 1.5T.

Assessment

Synthetic MR signals were created to mimic published GRE and UTE methods, using different R2* values (25–2000 s−1) and signal‐to‐noise ratios (SNR). Phantoms with varying iron concentrations were scanned at 1.5T. In vivo data were analyzed from 132 patients acquired at 1.5T. R2* was estimated by fitting using three signal models. Accuracy and precision of R2* measurements for UTE acquisition parameters (SNR, echo spacing [ΔTE], maximum echo time [TEmax]) and fitting methods were compared for simulated, phantom, and in vivo datasets.

Statistical Tests

R2* accuracy was determined from the relative error and by linear regression analysis. Precision was evaluated using coefficient of variation (CoV) analysis.

Results

In simulations, all models had high R2* accuracy (error <5%) and precision (CoV <10%) for all SNRs, shorter ΔTE (≤0.5 msec), and longer TEmax (≥10.1 msec); except the constant offset model overestimated R2* at the lowest SNR. In phantoms and in vivo, all models produced similar R2* values for different SNRs and shorter ΔTEs (slopes: 0.99–1.06, R2 > 0.99, P < 0.001). In all experiments, R2* results degraded for high R2* values with longer ΔTE (≥1 msec). In vivo, shorter and longer TEmax gave similar R2* results (slopes: 1.02–1.06, R2 > 0.99, P < 0.001) for the noise subtraction model for 25≤R2*≤2000 s−1. However, both quadratic and constant offset models, using shorter TEmax (≤4.7 msec) overestimated R2* and yielded high CoVs up to ∼170% for low R2* (<250 s−1).

Data Conclusion

UTE with TEmax ≥ 10.1 msec and ΔTE ≤ 0.5 msec yields accurate R2* estimates over the entire clinical HIC range. Monoexponential fitting with noise subtraction is the most robust signal model to changes in UTE parameters and achieves the highest R2* accuracy and precision.

Level of Evidence: 2

Technical Efficacy: Stage 2

J. Magn. Reson. Imaging 2019;49:1475–1488.
Effect of stevia supplementation of kale juice spheres on their quality changes during refrigerated shelf life
Authors: Klug Tâmmila V , Collado Elena , Martínez‐Hernández Ginés B , Artés Francisco , Artés‐Hernández Francisco
Published: October 2018

BACKGROUND

Kale is a vegetable that contains a high proportion of health‐promoting compounds although its consumption as a beverage is very limited due to its bitter flavor. Nonetheless, the bitter flavor of Brassica may be masked by sweetening. The effects were studied of different stevia extracts (CTRL, S0.5 (g L−1), S1.25 and S2.5) added to a kale beverage on the quality of kale juice spheres over a period of 7 days at 5 °C. Kale juice spheres were produced with a double‐spherification technique, which allowed hydrogel spheres to be produced with high mechanical resistance.

RESULTS

The addition of the stevia extracts did not affect the physicochemical quality of spheres. In particular, S2.5 spheres showed the least color changes after 7 days. All spheres showed good microbiological quality throughout storage, with loads < 7 log CFU g−1, regardless of the stevia concentration. The sulforaphane content of kale spheres was not affected by the stevia supplementation over the 7‐day period.

CONCLUSION

The addition of stevia to the kale juice spheres led to a better flavor without altering product quality during refrigerated storage. © 2018 Society of Chemical Industry
Investigation of excited‐state dynamics upon both photo‐excitation and electro‐excitation of thermally activated delayed fluorescent molecules
Authors: Wang Peng , Huang Qingyu , Zhao Suling , Xu Zheng , Song Dandan , Qiao Bo , Zheng Weiye , Chen Junfei , Yan Guang
Published: October 2018

Exciton dynamics is one of the core issues lies in the field of achieving high efficiency organic light‐emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) molecules. The authors briefly review the host dependence of TADF dopant and then discuss the host–guest interaction in TADF OLEDs. By the means of transient electroluminescence measurement, the dynamics of triplet and singlet excitons are studied. Results show that host material with high T1 energy levels, large spectral overlap with TADF dopant's absorption, and free of exciplex formation exhibits higher TADF character. Furthermore, the underlying reason for the efficiency roll‐off of the TADF OLEDs is clarified to be attributed to deeply trapped charges.
Kinetics of Maillard reaction in a chicken meat model system using a multiresponses modeling approach
Authors: Chansataporn W. , Prathumars P. , Nopharatana M. , Siriwattanayotin S. , Tangduangdee C.
Published: October 2018

This research aimed to study the Maillard reaction pathway in chicken meat. Owing to the complexity of real chicken meat, which is composed of many different types of amino acids and reducing sugars, the experiment was initiated with a glucose/lysine model system with the same concentration ratio of reactants as found in chicken meat. By considering glucose as the rate‐limiting substrate, a kinetic model of the glucose/lysine model system was developed. Methylglyoxal (MG) was found to be the principal important α‐dicarbonyl compound intermediates that further reacted to form melanoidins. Pyridine was a major volatile compound in this model system. The optimized kinetic model was then further validated in a chicken extract, for which the Maillard reaction mechanism has not been elucidated. However, the kinetic model of the glucose/lysine system could not explain the Maillard reaction in the chicken extract, presumably because both types of intermediates and reaction pathway depend on the reactants. Thus, a kinetic model of the Maillard reaction in the chicken extract was developed based on the main types of detected intermediates. Overall, MG was the central intermediate and acted as a substrate for the formation of furfural, volatile compounds, melanoidins, and unknown carbonyl compound(s) (Cn). Pyrazines and aldehydes were the major volatile compounds in the chicken extract.
Sensitivity analysis of the parameter‐efficient distributed (PED) model for discharge and sediment concentration estimation in degraded humid landscapes
Authors: Ochoa‐Tocachi Boris F. , Alemie Tilashwork C. , Guzman Christian D. , Tilahun Seifu A. , Zimale Fasikaw A. , Buytaert Wouter , Steenhuis Tammo S.
Published: October 2018

Sustainable development in degraded landscapes in the humid tropics requires effective soil and water management practices. Coupled hydrological‐erosion models have been used to understand and predict the underlying processes at watershed scale and the effect of human interventions. One prominent tool is the parameter‐efficient distributed (PED) model, which improves on other models by considering a saturation‐excess runoff generation driving erosion and sediment transport in humid climates. This model has been widely applied at different scales for the humid monsoonal climate of the Ethiopian Highlands, with good success in estimating discharge and sediment concentrations. However, previous studies performed manual calibration of the involved parameters without reporting sensitivity analyses or assessing equifinality. The aim of this article is to provide a multiobjective global sensitivity analysis of the PED model using automatic random sampling implemented in the SAFE Toolbox. We find that relative parameter sensitivity depends greatly on the purpose of model application and the outcomes used for its evaluation. Five of the 13 PED model parameters are insensitive for improving model performance. Additionally, associating behavioural parameter values with a clear physical meaning provides slightly better results and helps interpretation. Lastly, good performance in one module does not translate directly into good performance in the other module. We interpret these results in terms of the represented hydrological and erosion processes and recommend field data to inform model calibration and validation, potentially improving land degradation understanding and prediction and supporting decision‐making for soil and water conservation strategies in degraded humid landscapes.
Development of Clinical Criteria for Functional Assessment to Predict Primary Nonfunction of High‐Risk Livers Using Normothermic Machine Perfusion
Authors: Mergental Hynek , Stephenson Barnaby T. F. , Laing Richard W. , Kirkham Amanda J. , Neil Desley A. H. , Wallace Lorraine L. , Boteon Yuri L. , Widmer Jeannette , Bhogal Ricky H. , Perera M. Thamara P. R. , Smith Amanda , Reynolds Gary M. , Yap Christina , Hübscher Stefan G. , Mirza Darius F. , Afford Simon C.
Published: October 2018

Increased use of high‐risk allografts is critical to meet the demand for liver transplantation. We aimed to identify criteria predicting viability of organs, currently declined for clinical transplantation, using functional assessment during normothermic machine perfusion (NMP). Twelve discarded human livers were subjected to NMP following static cold storage. Livers were perfused with a packed red cell–based fluid at 37°C for 6 hours. Multilevel statistical models for repeated measures were employed to investigate the trend of perfusate blood gas profiles and vascular flow characteristics over time and the effect of lactate‐clearing (LC) and non‐lactate‐clearing (non‐LC) ability of the livers. The relationship of lactate clearance capability with bile production and histological and molecular findings were also examined. After 2 hours of perfusion, median lactate concentrations were 3.0 and 14.6 mmol/L in the LC and non‐LC groups, respectively. LC livers produced more bile and maintained a stable perfusate pH and vascular flow >150 and 500 mL/minute through the hepatic artery and portal vein, respectively. Histology revealed discrepancies between subjectively discarded livers compared with objective findings. There were minimal morphological changes in the LC group, whereas non‐LC livers often showed hepatocellular injury and reduced glycogen deposition. Adenosine triphosphate levels in the LC group increased compared with the non‐LC livers. We propose composite viability criteria consisting of lactate clearance, pH maintenance, bile production, vascular flow patterns, and liver macroscopic appearance. These have been tested successfully in clinical transplantation. In conclusion, NMP allows an objective assessment of liver function that may reduce the risk and permit use of currently unused high‐risk livers.
Impact of high‐grain diet feeding on mucosa‐associated bacterial community and gene expression of tight junction proteins in the small intestine of goats
Authors: Liu Junhua , Xue Chunxu , Sun Daming , Zhu Weiyun , Mao Shengyong
Published: October 2018

The objective of this study was to investigate the impact of a high‐grain (HG) diet on the microbial fermentation, the composition of the mucosa‐associated bacterial microbiota, and the gene expression of tight junction proteins in the small intestine of goats. In the present study, we randomly assigned 10 male goats to either a hay diet (n = 5) or a HG diet (56.5% grain; n = 5) and then examined changes in the bacterial community using Illumina MiSeq sequencing and the expression of tight junction proteins using qRT‐PCR in the mucosa of the small intestine. The results showed that HG diet decreased the luminal pH (p = 0.005) and increased the lipopolysaccharide content (p < 0.001) in the digesta of the ileum, and it increased the concentration of total volatile fatty acids in the digesta of the jejunum (p = 0.015) and ileum (p = 0.007) compared with the hay diet. MiSeq sequencing results indicated that the HG diet increased (FDR = 0.007–0.028) the percentage of the genera Stenotrophomonas, Moraxella, Lactobacillus, and Prevotella in jejunal mucosa but decreased (FDR = 0.016) the abundance of Christensenellaceae R7 group in the ileal mucosa compared with the hay diet. Furthermore, the HG diet caused downregulation of the mRNA expression of claudin‐4, occludin, and ZO‐1 in jejunal and ileal mucosa (p < 0.05). Collectively, our data suggested that the HG diet induced changes in the relative abundance of some mucosa‐associated bacteria, in addition to downregulation of the mRNA expression of tight junction proteins in the small intestine. These findings provide new insights into the adaptation response of the small intestine to HG feeding in ruminants.
Engineered cyclodextrin glucanotransferases from Bacillus sp. G‐825‐6 produce large‐ring cyclodextrins with high specificity
Authors: Sonnendecker Christian , Melzer Susanne , Zimmermann Wolfgang
Published: October 2018

Cyclodextrin glucanotransferases (CGTases) synthesize cyclic oligosaccharides (cyclodextrins, CD) from starch. A CGTase from Bacillus sp. G‐825‐6 was engineered by site‐directed mutagenesis at two positions by the construction of the variants Y183W, Y183R, D358R, Y183W/D358R, and Y183R/D358R. Among CD composed of 7–12 glucose units (CD7–CD12), Y183W mainly produced CD8. Y183R had completely lost its ability to synthesize CD7, and CD8 and the larger CD were the only cyclic oligosaccharides produced. D358R also formed mainly CD8–CD12 during a reaction time of 24 hr. The double mutant Y183W/D358R showed combined characteristics of the single mutations with very low CD7 cyclization activity and an increased formation of the larger CD. The results show that CGTases synthesizing mainly CD8–CD12 can be constructed allowing a convenient production of larger CD in significant amounts as host molecules in supramolecular complexing reactions.