bluuebunny/crossref_metadata_2025 huggingface dataset:
The nucleosomal acidic patch relieves auto-inhibition by the ISWI remodeler SNF2h
Authors: Gamarra Nathan , Johnson Stephanie L , Trnka Michael J , Burlingame Alma L , Narlikar Geeta J
Published: April 2018

ISWI family chromatin remodeling motors use sophisticated autoinhibition mechanisms to control nucleosome sliding. Yet how the different autoinhibitory domains are regulated is not well understood. Here we show that an acidic patch formed by histones H2A and H2B of the nucleosome relieves the autoinhibition imposed by the AutoN and the NegC regions of the human ISWI remodeler SNF2h. Further, by single molecule FRET we show that the acidic patch helps control the distance travelled per translocation event. We propose a model in which the acidic patch activates SNF2h by providing a landing pad for the NegC and AutoN auto-inhibitory domains. Interestingly, the INO80 complex is also strongly dependent on the acidic patch for nucleosome sliding, indicating that this substrate feature can regulate remodeling enzymes with substantially different mechanisms. We therefore hypothesize that regulating access to the acidic patch of the nucleosome plays a key role in coordinating the activities of different remodelers in the cell.
Hexameric and pentameric complexes of the ExbBD energizer in the Ton system
Authors: Maki-Yonekura Saori , Matsuoka Rei , Yamashita Yoshiki , Shimizu Hirofumi , Tanaka Maiko , Iwabuki Fumie , Yonekura Koji
Published: April 2018

Gram-negative bacteria import essential nutrients such as iron and vitamin B12 through outer membrane receptors. This process utilizes proton motive force harvested by the Ton system made up of three inner membrane proteins, ExbB, ExbD and TonB. ExbB and ExbD form the proton channel that energizes uptake through TonB. Recently, crystal structures suggest that the ExbB pentamer is the scaffold. Here, we present structures of hexameric complexes of ExbB and ExbD revealed by X-ray crystallography and single particle cryo-EM. Image analysis shows that hexameric and pentameric complexes coexist, with the proportion of hexamer increasing with pH. Channel current measurement and 2D crystallography support the existence and transition of the two oligomeric states in membranes. The hexameric complex consists of six ExbB subunits and three ExbD transmembrane helices enclosed within the central channel. We propose models for activation/inactivation associated with hexamer and pentamer formation and utilization of proton motive force.
Fighting the Enemy Within? Challenging Minor Principles of Professionalism in Care and Welfare
Authors: Trappenburg Margo , Noordegraaf Mirko
Published: April 2018

Wilensky’s seminal article on professionals mentions three identifying characteristics besides the familiar specialized knowledge, autonomy and professional ideology. These are the referral principle, which states that professionals should refer clients to a colleague with a different specialty if necessary, the principle of sloughing off, which dictates that professionals allocate less rewarding parts of their job to lesser paid assistants, and the principle of impersonal service delivery, which admonishes professionals to treat clients equally. A changing clientele in health care and social care warrants a reappraisal of these three principles. Population ageing necessitates a reappraisal in health care. The deinstitutionalization of people with psychiatric or mental disabilities necessitates a reappraisal in social care. Referral, sloughing off and impersonal service delivery are professional characteristics that concur with managerial or political objectives. Managers and politicians are partly responsible for their widespread application. Hence, professionals need their help to fight this “enemy within professionalism.”
Non-dispersive phloem-protein bodies (NPBs) ofPopulus trichocarpaconsist of a SEOR protein and do not respond to cell wounding and Ca2+
Authors: Mullendore Daniel L. , Ross-Elliott Timothy , Liu Yan , Hellmann Hanjo H. , Roalson Eric H. , Peters Winfried S. , Knoblauch Michael
Published: April 2018

Differentiating sieve elements in the phloem of angiosperms produce abundant phloem-specific proteins before their protein synthesis machinery is degraded. These P-proteins initially form dense bodies, which disperse into individual filaments when the sieve element matures. In some cases, however, the dense protein agglomerations remain intact and are visible in functional sieve tubes as non-dispersive P-protein bodies, or NPBs. Species exhibiting NPBs are distributed across the entire angiosperm clade. We found that NPBs in the model tree,Populus trichocarpa, resemble the protein bodies described from other species of the order Malpighiales as they all consist of coaligned tubular fibrils bundled in hexagonal symmetry. NPBs of all Malpighiales tested proved unresponsive to sieve tube wounding and Ca2+. TheP. trichocarpaNPBs consisted of a protein encoded by a gene that in the genome database of this species had been annotated as a homolog ofSEOR1(sieve element occlusion-related 1) inArabidopsis. Sequencing of the gene in our plants corroborated this interpretation, and we named the genePtSEOR1. Previously characterized SEOR proteins form irregular masses of P-protein slime in functional sieve tubes. We conclude that a subgroup of these proteins is involved in the formation of NPBs at least in the Malpighiales, and that these protein bodies have no role in rapid wound responses of the sieve tube network.
A Rare Dispersion of Low‐Salinity, High‐Gelbstoff, High‐Primary Production Water in the East China Sea During the Summer of 2010: Possible Influence of the ENSO
Authors: Siswanto Eko , Xu Yongjiu , Ishizaka Joji
Published: April 2018

We applied ocean color algorithms and a primary production model to a 13‐year ocean color data set to assess interannual variations of Changjiang‐influenced water (CIW) dispersion, with an emphasis on the unusual CIW dispersion during July 2010. The characteristics of the CIW offshore dispersion were primarily driven by alongshore winds and secondarily by the Changjiang discharge, the interannual variations of which were linked to the El Niño/La Niña. The unusual southeastward dispersion of CIW in July 2010 was attributed to a relatively weak southwesterly wind (with southwesterly wind anomalies) and high Changjiang discharge (after the El Niño peak in winter). In July 2010, the CIW, which is characterized by low‐salinity, high‐gelbstoff, and high‐primary production, intruded into the Kuroshio Current axis to form a rare band of CIW that flowed toward an area south of Japan. The southeastward dispersion of CIW in July 2003 was also unusual, but it did not extend as far as in July 2010, perhaps because of the relatively strong southwesterly winds and low Changjiang discharge in July 2003. During La Niña events, the dispersion of CIW retreated toward the coast due to prevailing northeasterly wind anomalies. We confirmed that the CIW in July 2010 was characterized by low‐salinity, abundant phytoplankton biomass, and high biological production. The fact that high biological production and the peak of Changjiang discharge occurred in the same month (July) in 2010 indicated that biogeochemical production stimulated by nutrients from the Changjiang was higher than during normal summer conditions.
Overview of the Arctic Sea State and Boundary Layer Physics Program
Authors: Thomson Jim , Ackley Stephen , Girard‐Ardhuin Fanny , Ardhuin Fabrice , Babanin Alex , Boutin Guillaume , Brozena John , Cheng Sukun , Collins Clarence , Doble Martin , Fairall Chris , Guest Peter , Gebhardt Claus , Gemmrich Johannes , Graber Hans C. , Holt Benjamin , Lehner Susanne , Lund Björn , Meylan Michael H. , Maksym Ted , Montiel Fabien , Perrie Will , Persson Ola , Rainville Luc , Erick Rogers W. , Shen Hui , Shen Hayley , Squire Vernon , Stammerjohn Sharon , Stopa Justin , Smith Madison M. , Sutherland Peter , Wadhams Peter
Published: April 2018

A large collaborative program has studied the coupled air‐ice‐ocean‐wave processes occurring in the Arctic during the autumn ice advance. The program included a field campaign in the western Arctic during the autumn of 2015, with in situ data collection and both aerial and satellite remote sensing. Many of the analyses have focused on using and improving forecast models. Summarizing and synthesizing the results from a series of separate papers, the overall view is of an Arctic shifting to a more seasonal system. The dramatic increase in open water extent and duration in the autumn means that large surface waves and significant surface heat fluxes are now common. When refreezing finally does occur, it is a highly variable process in space and time. Wind and wave events drive episodic advances and retreats of the ice edge, with associated variations in sea ice formation types (e.g., pancakes, nilas). This variability becomes imprinted on the winter ice cover, which in turn affects the melt season the following year.
An integrated analysis of genome‐wide DNA methylation and gene expression data in hepatocellular carcinoma
Authors: Sun Xiang‐Jun , Wang Ming‐Chun , Zhang Feng‐Hua , Kong Xiao
Published: April 2018

Despite progress in the treatment of hepatocellular carcinoma (HCC), 5‐year survival rates remain low. Thus, a more comprehensive approach to explore the mechanism of HCC is needed to provide new leads for targeted therapy. We performed an integrated analysis to discover the relationship between DNA methylation and gene expression in hepatocellular carcinoma (HCC). DNA methylation and gene expression data for HCC were downloaded from The Cancer Genome Atlas (TCGA) database, and differential analysis was performed. Correlation analysis between DNA methylation and gene expression data was then performed in R language. Finally, we selected several crucial genes and evaluated their potential use as diagnostic biomarkers for HCC. In total, 1135 differentially DNA‐methylated CpG sites (DMCs), 377 differentially methylated regions (DMRs), and 1194 differentially expressed genes (DEGs) were identified in HCC. Among the DEGs, 14 genes (ALX3, B4GALNT1, CTHRC1, DLX5, EMX1, IRX3, OTX1, SIX2, TLX1, VASH2, ZIC2, ZIC4, ZIC5, and ZNF695) exhibited changes in DNA methylation in terms of CpG sites or CpG island (CGI) level, of which TLX1 and ZIC4 had the most DMCs (12 and 13, respectively). Further analysis of CTHRC1, ZIC4, SIX2, VASH2, IL17D, TLX1, OTX1, and LART, examining alterations in both DNA methylation and gene expression level in HCC, showed their potential diagnostic value for HCC was better at the gene expression level than that the DNA methylation level. The DNA methylation status of CTHRC1, VASH2, and IL7D was significantly associated with HCC overall survival (P‐value <0.05). This systemic analysis identified a group of novel gene signatures (CTHRC1, ZIC4, and OTX1) that may be regulated by DNA hypermethylation, which may be closely associated with HCC.
Shortcut Models Based on Molecular Structure for Life Cycle Impact Assessment: The Case of the FineChem Tool and Beyond
Authors: Papadokonstantakis Stavros , Baxevanidis Pantelis , Marcoulaki Effie , Badr Sara , Kokossis Antonis
Published: April 2018

The sections in this article are

Introduction

Concept and Development of the FineChem Tool

Illustrative Applications of the FineChem Tool

LCAAspects of Solvent Selection for PostcombustionCO2Capture (PCC)

Bio‐Based Production of Platform Chemicals

Toward A New Group Contribution‐Based Version of the FineChem Tool

Introduction toGCmodels

Development ofGC‐BasedLCAModels

Screening for Substances with Desirable Properties

Illustrative Example of Screening Molecules

Conclusions and Outlook
Green Chemistry Metrics and Life Cycle Assessment for Microflow Continuous Processing
Authors: Zhang Lihua , Wang Qi , Hessel Volker
Published: April 2018

In this chapter, major green metrics are described as they have been applied to microflow continuous processes (e.g., mass intensity (MI)/process mass intensity (PMI),E‐factor, atom economy, etc.). Thereafter, life cycle assessment (LCA) and life cycle costing (LCC) analysis are reviewed in the framework of their application to evaluate microflow continuous processes. Green metrics,LCA, andLCCallow an objective quantitative measurement and decision support tool to evaluate the ecological, environmental as well as the economic impact of a chemical synthesis and process. Within the approach of green chemistry, continuous microflow processing has become a major method to achieve process intensification and engineering support. Accordingly, the specific sustainability characteristics of microflow continuous processes will be described. A comparison of microscale continuous processes and conventional macroscale processes accompanied by green metrics andLCAwill be conducted. This is done in a hierarchical manner, starting from single microflow reaction optimization (both with single and bundled innovation drivers) toward combined microflow reaction separation and microflow multistep reactions. The production volume under consideration is both small (pharma) and large (fine/bulk chemical). This scenario analysis allows one to draw some generic conclusions about the environmental opportunities of continuous microflow technology and, vice versa, on the suitability of these green assessment tools. Each case scenario is for a typical, mostly experimentally validated microreactor application and illustrates the pros and cons of microflow continuous processes in the fine chemical and pharmaceutical industry. The environmental analysis is completed by a snapshot ofLCCanalysis for these microreactor case scenarios.
Prior Learning Assessment: Does Dewey's Theory Offer Insight?
Authors: Harris Judy
Published: April 2018

This chapter evaluates Dewey's thinking in relation to the theorization of Prior Learning Assessment (PLA). It compares Dewey's concepts with ideas from social realism, Vygotsky, and cultural historical activity theory, illustrated by PLA research in South Africa.
Parotid gland radiation dose‐xerostomia relationships based on actual delivered dose for nasopharyngeal carcinoma
Authors: Lou Jingjiao , Huang Pu , Ma Changsheng , Zheng Yue , Chen Jinhu , Liang Yueqiang , Li Hongsheng , Yin Yong , Liu Danhua , Yu Gang , Li Dengwang
Published: April 2018

Xerostomia induced by radiotherapy is a common toxicity for head and neck carcinoma patients. In this study, the deformable image registration of planning computed tomography (CT) and weekly cone‐beam CT (CBCT) was used to override the Hounsfield unit value of CBCT, and the modified CBCT was introduced to estimate the radiation dose delivered during the course of treatment. Herein, the beams from each patient's treatment plan were applied to the modified CBCT to construct the weekly delivered dose. Then, weekly doses were summed together to obtain the accumulated dose. A total of 42 parotid glands (PGs) of 21 nasopharyngeal carcinoma patients were analyzed. Doses delivered to the parotid glands significantly increased compared with the planning doses. V20, V30, V40, Dmean, and D50 increased by 11.3%, 28.6%, 44.4%, 9.5%, and 8.4% respectively. Of the 21 patients included in the study, eight developed xerostomia and the remaining 13 did not. Both planning and delivered PG Dmean for all patients exceeded tolerance (26 Gy). Among the 21 patients, the planning dose and delivered dose of Dmean were 30.6 Gy and 33.6 Gy, respectively, for patients with xerostomia, and 26.3 Gy and 28.0 Gy, respectively, for patients without xerostomia. The D50 of the planning and delivered dose for patients was below tolerance (30 Gy). The results demonstrated that the p‐value of V20, V30, D50, and Dmean difference of the delivery dose between patients with xerostomia and patients without xerostomia was less than 0.05. However, for the planning dose, the significant dosimetric difference between the two groups only existed in D50 and Dmean. Xerostomia is closely related to V20, V30, D50, and Dmean.
The NRF2 pathway as potential biomarker for dimethyl fumarate treatment in multiple sclerosis
Authors: Hammer Anna , Waschbisch Anne , Kuhbandner Kristina , Bayas Antonios , Lee De‐Hyung , Duscha Alexander , Haghikia Aiden , Gold Ralf , Linker Ralf A.
Published: April 2018

Objective

Immunological studies have demonstrated a plethora of beneficial effects of dimethyl fumarate (DMF) on various cell types. However, the cellular and molecular targets are incompletely understood and response markers are scarce. Here, we focus on the relation between nuclear factor (erythroid‐derived 2)‐like 2 (NRF2) pathway induction under DMF therapy and the composition of the blood immune cell compartment and clinical efficacy in relapsing‐remitting multiple sclerosis (MS) patients.

Methods

We explored effects of DMF on peripheral immune cell subsets by flow cytometric and transcriptional analysis of serial blood samples obtained from 43 MS patients during the first year of therapy.

Results

Gene expression analysis proved activation of NRF2 signaling under DMF therapy that was paralleled by a temporal expansion of FoxP3+ regulatory T cells, CD56bright natural killer cells, plasmacytoid dendritic cells, and a decrease in CD8+ T cells, B cells, and type 1 myeloid dendritic cells. In a subgroup of 28 patients with completely available clinical data, individuals with higher levels of the NRF2 target gene NAD(P)H quinone dehydrogenase 1 (NQO1) 4–6 weeks after DMF therapy initiation were more likely to achieve no evidence of disease activity status 1 year later. The degree of NQO1 induction further correlated with patient age.

Interpretation

We demonstrate that positive effects of DMF on the clinical outcome are paralleled by induction of the antioxidant NRF2 transcriptional pathway and a shift toward regulatory immune cell subsets in the periphery. Our data identify a role of the NRF2 pathway as potential biomarker for DMF treatment in MS.
Targeting and Modulation of Liver Myeloid Immune Cells by Hard‐Shell Microbubbles
Authors: Warzecha Klaudia T. , Bartneck Matthias , Möckel Diana , Appold Lia , Ergen Can , Al Rawashdeh Wa'el , Gremse Felix , Niemietz Patricia M. , Jahnen‐Dechent Willi , Trautwein Christian , Kiessling Fabian , Lammers Twan , Tacke Frank
Published: April 2018

Poly n‐butylcyanoacrylate (PBCA)‐based hard‐shell microbubbles (MB) have manifold biomedical applications, including targeted drug delivery or contrast agents for ultrasound (US)‐based liver imaging. MB and their fragments accumulate in phagocytes, especially in the liver, but it is unclear if MB affect the function of these immune cells. Herein, it is shown that human primary monocytes internalize different PBCA‐MB by phagocytosis, which transiently inhibits monocyte migration in vertical chemotaxis assays and renders monocytes susceptible to cytotoxic effects of MB during US‐guided destruction. Conversely, human macrophage viability and function, including cytokine release and polarization, remain unaffected after MB uptake. After intravenous injection in mice, MB predominantly accumulate in liver, especially in hepatic phagocytes (monocytes and Kupffer cells). Despite efficiently targeting myeloid immune cells in liver, MB or MB after US‐elicited burst do not cause overt hepatotoxicity or inflammation. Furthermore, MB application with or without US‐guided burst does not aggravate the course of experimental liver injury in mice or the inflammatory response to liver injury in vivo. In conclusion, PBCA‐MB have immunomodulatory effects on primary human myeloid cells in vitro, but do not provoke hepatotoxicity, inflammation or altered response to liver injury in vivo, suggesting the safety of these MB for diagnostic and therapeutic purposes.
Enhanced Targeted Delivery of Doxorubicin Based on Acid Induced Charge Reversal and Combinational Stimuli‐Responsive Nanocarrier
Authors: Xue Yanan , Tao Lijun , Zhou Yang , Liu Jie , Yu Bo , Long Sihui , Huang Shiwen , Yu Faquan
Published: April 2018

To elevate the efficacy and to attenuate the adverse effects remain a tough challenge in exploring anticancer drug delivery systems. A nanocarrier characteristic of acid induced charge reversal and acid/redox/magnetic combinational stimuli‐responsiveness is designed. This system exhibits weaker repulsion between the carrier and the cancer cell membrane, resulting in enhanced uptake. After nanocarriers enter the cell, the system exhibits negative‐to‐positive charge reversal in response to the low intracellular pH value. Moreover, after the uptake, the carrier will be further dissociated by glutathione in cytoplasm via the reduction of the disulfide bond, leading to the rapid release of the encapsulated DOX into the nuclei. In vitro release study expresses the sequent stimulus release profile. The antitumor activity tested in CT26 tumor‐bearing mice reveals efficient therapeutic efficacy and as low adverse effect as PBS. H&E staining and immunohistochemical analysis of tumor tissues as well as pathological test of tissue sections of vital organs confirm the high antitumor activity and low tissue toxicity. Thus, the belief that this system has a good prospect in the field of cancer clinical chemotherapy.
Conjugated Polymer Nanoparticle–Graphene Oxide Charge‐Transfer Complexes
Authors: Istif Emin , Hernández‐Ferrer Javier , Urriolabeitia Esteban P. , Stergiou Anastasios , Tagmatarchis Nikos , Fratta Giuseppe , Large Matthew J. , Dalton Alan B. , Benito Ana M. , Maser Wolfgang K.
Published: April 2018

The game‐changing role of graphene oxide (GO) in tuning the excitonic behavior of conjugated polymer nanoparticles is described for the first time. This is demonstrated by using poly(3‐hexylthiophene) (P3HT) as a benchmark conjugated polymer and employing an in situ reprecipitation approach resulting in P3HT nanoparticles (P3HTNPs) with sizes of 50–100 nm in intimate contact with GO. During the self‐assembly process, GO changes the crystalline packing of P3HT chains in the forming P3HTNPs from H to H/J aggregates exhibiting exciton coupling constants as low as 2 meV, indicating favorable charge separation along the P3HT chains. Concomitantly, π–π interface interactions between the P3HTNPs and GO sheets are established resulting in the creation of P3HTNPs–GO charge‐transfer complexes whose energy bandgaps are lowered by up to 0.5 eV. Moreover, their optoelectronic properties, preestablished in the liquid phase, are retained when processed into thin films from the stable aqueous dispersions, thus eliminating the critical dependency on external processing parameters. These results can be transferred to other types of conjugated polymers. Combined with the possibility of employing water based “green” processing technologies, charge‐transfer complexes of conjugated polymer nanoparticles and GO open new pathways for the fabrication of improved optoelectronic thin film devices.
Polyformamidine‐Derived Non‐Noble Metal Electrocatalysts for Efficient Oxygen Reduction Reaction
Authors: Pardo Pérez Laura C. , Sahraie Nastaran Ranjbar , Melke Julia , Elsässer Patrick , Teschner Detre , Huang Xing , Kraehnert Ralph , White Robin J. , Enthaler Stephan , Strasser Peter , Fischer Anna
Published: April 2018

A facile approach for the template‐free synthesis of highly active non‐noble metal based oxygen reduction reaction (ORR) electrocatalysts is presented. Porous Fe−N−C/Fe/Fe3C composite materials are obtained by pyrolysis of defined precursor mixtures of polyformamidine (PFA) and FeCl3 as nitrogen‐rich carbon and iron sources, respectively. Selection of pyrolysis temperature (700–1100 °C) and FeCl3 loading (5–30 wt%) yields materials with differing surface areas, porosity, graphitization degree, nitrogen and iron content, as well as ORR activity. While the ORR activity of Fe‐free materials is limited (i.e., synthesized from pure PFA), a huge increase in activity is observed for catalysts containing Fe, revealing the participation of the metal dopant in the construction of active electrocatalytic sites. Further activity improvement is achieved via acid‐leaching and repeated pyrolysis, a result which is attributed to the creation of new active sites located at the surface of the porous nitrogen‐doped carbon by dissolution of the Fe and Fe3C nanophases. The best performing catalyst, which was synthesized with a low Fe loading (i.e., 5 wt%) and at a pyrolysis temperature of 900 °C, exhibits high activity, excellent H2O selectivity, extended stability, in both basic and acidic media as well as a remarkable tolerance toward methanol.
Er3+ Sensitized Photon Upconversion Nanocrystals
Authors: Cheng Xingwen , Pan Yue , Yuan Ze , Wang Xiuwen , Su Wenhong , Yin Lisha , Xie Xiaoji , Huang Ling
Published: April 2018

Lanthanide doped upconversion nanocrystals, showing bright future in diverse fields, are typically excited by ≈700–1000 nm light when Nd3+ and Yb3+ are used as sensitizers. Thus far, extending the excitation range of upconversion nanocrystals is still a formidable challenge. Herein, a new type of upconversion nanocrystals is reported, using Er3+ ions as sensitizers, which can be excited by 1532 nm light located in the second near‐infrared biological window. Through Er3+ sensitization, upconversion emission from a series of activators, including Nd3+, Ho3+, Eu3+, and Tm3+, is obtained and can be modulated by Yb3+ codoping. In addition, Er3+ sensitized photon upconversion of Ho3+ and Tm3+ can be further enhanced by shell coating. It is found that Er3+ sensitized upconversion processes are mainly dependent on the energy transfer between Er3+ ions and activators. Considering the demonstration of anticounterfeiting by using this newly designed nanocrystal, it is anticipated that these results can bring more opportunities to upconversion nanomaterials in other aspects, ranging from lasing to super resolution imaging.
Spiky Fe3O4@Au Supraparticles for Multimodal In Vivo Imaging
Authors: Wang Weiwei , Hao Changlong , Sun Maozhong , Xu Liguang , Xu Chuanlai , Kuang Hua
Published: April 2018

Nanomaterials with high biocompatibility and efficient photothermal conversion have drawn tremendous attention for tumor diagnosis and treatment. In this study, spiky Fe3O4@Au supraparticles (SPs) are used as phototherapy and multimodal imaging agents. The SPs show excellent photothermal and photodynamic therapeutic effects, with a photothermal conversion efficiency of 31%, and allow tumor‐targeted imaging, including computed tomographic, photoacoustic, and magnetic resonance imaging. The SPs show excellent biocompatibility both in vitro and in vivo. Furthermore, because of their remarkable absorption at near‐infrared region, the SPs obliterate a tumor under 808 nm irradiation. With their capacity for highly integrated multimodal imaging and multiple therapeutic functions, SPs are a promising agent for application to clinical practice.
Comparative Study of Two Droplet‐Based Dissolving Microneedle Fabrication Methods for Skin Vaccination
Authors: Lee Chisong , Kim Hongil , Kim Suyong , Lahiji Shayan F. , Ha Na‐Young , Yang Huisuk , Kang Geonwoo , Nguyen Hai Yen Thi , Kim Yuri , Choi Myung‐Sik , Cho Nam‐Hyuk , Jung Hyungil
Published: April 2018

Dissolving microneedles (DMNs) have been widely studied in medical applications due to their pain‐free administration, superior efficiency, and safe drug delivery. In skin vaccination, preserving the activity of the encapsulated antigen is an important consideration, as antigen activity is lost during DMN fabrication because of various stress factors. These stress factors vary between fabrication methods and each method affects the antigen's activity to different degrees. In this study, the activity of encapsulated antigens delivered by DMNs is compared between two recently developed DMN fabrication methods; droplet‐born air blowing (DAB) and centrifugal lithography (CL) for a model scrub typhus vaccine antigen, ScaA. Although the in vitro analysis of ScaA‐loaded DMNs (ScaA‐DMNs) does not show any differences in physical properties depending on the fabrication methods, the immunogenicity of the CL‐produced ScaA‐DMN is significantly higher based on cytokine measurement and humoral immunity. DAB and CL differ in their solidification conditions, suggesting that solidification factors critically affect the encapsulated antigen's activity. ScaA‐DMNs may also be stably stored for 4 weeks at room temperature. In conclusion, CL is a superior DMN fabrication method compared with DAB, and this study proves that DMN is feasible and practical for skin vaccination.
Assembly of PEG Microgels into Porous Cell‐Instructive 3D Scaffolds via Thiol‐Ene Click Chemistry
Authors: Xin Shangjing , Wyman Omar M. , Alge Daniel L.
Published: April 2018

The assembly of microgel building blocks into 3D scaffolds is an emerging strategy for tissue engineering. A key advantage is that the inherent microporosity of these scaffolds provides cells with a more permissive environment than conventional nanoporous hydrogels. Here, norbornene‐bearing poly(ethylene glycol) (PEG) based microgels are assembled into 3D cell‐instructive scaffolds using a PEG‐dithiol linker and thiol‐ene click photopolymerization. The bulk modulus of these materials depends primarily on the crosslink density of the microgel building blocks. However, the linker and initiator concentrations used during assembly have significant effects on cell spreading and proliferation when human mesenchymal stem cells (hMSCs) are incorporated in the scaffolds. The cell response is also affected by the properties of the modular microgel building blocks, as hMSCs growing in scaffolds assembled from stiff but not soft microgels activate Yes‐associated protein signaling. These results indicate that PEG microgel scaffolds assembled via thiol‐ene click chemistry can be engineered to provide a cell‐instructive 3D milieu, making them a promising 3D platform for tissue engineering.
Organic 2D Optoelectronic Crystals: Charge Transport, Emerging Functions, and Their Design Perspective
Authors: Park Sang Kyu , Kim Jin Hong , Park Soo Young
Published: April 2018

2D organic semiconductor crystals are emerging as a fascinating platform with regard to their applications in organic field‐effect transistors (OFETs), attributed to their enhanced charge transport efficiency and their new optoelectronic functions, based on their unique morphological features. Advances in material processing techniques have not only enabled easy fabrication of few‐monolayered 2D nanostructures but also facilitated exploration of the interesting properties induced by characteristic 2D morphologies. However, to date, only a limited number of representative organic semiconductors have been utilized in organic 2D optoelectronics. Therefore, in order to further spur this research, an intuitive crystal engineering principle for realizing organic 2D crystals is required. In this regard, here, not only the important implications of applying 2D structures to OFET devices are discussed but also a crystal engineering protocol is provided that first predicts molecular arrangements depending on the molecular factors, which is followed by realizing 2D supramolecular synthon networks for different molecular packing motifs. It is expected that 2D organic semiconductor crystals developed by this approach will pave a promising way toward next‐generation organic 2D optoelectronics.
Real‐Time Observation of Order‐Disorder Transformation of Organic Cations Induced Phase Transition and Anomalous Photoluminescence in Hybrid Perovskites
Authors: Yang Bin , Ming Wenmei , Du Mao‐Hua , Keum Jong K. , Puretzky Alexander A. , Rouleau Christopher M. , Huang Jinsong , Geohegan David B. , Wang Xiaoping , Xiao Kai
Published: April 2018

A fundamental understanding of the interplay between the microscopic structure and macroscopic optoelectronic properties of organic‐inorganic hybrid perovskite materials is essential to design new materials and improve device performance. However, how exactly the organic cations affect the structural phase transition and optoelectronic properties of the materials is not well understood. Here, real‐time, in situ temperature‐dependent neutron/X‐ray diffraction and photoluminescence (PL) measurements reveal a transformation of the organic cation CH3NH3
+ from order to disorder with increasing temperature in CH3NH3PbBr3 perovskites. The molecular‐level order‐to‐disorder transformation of CH3NH3
+ not only leads to an anomalous increase in PL intensity, but also results in a multidomain to single‐domain structural transition. This discovery establishes the important role that organic cation ordering has in dictating structural order and anomalous optoelectronic phenomenon in hybrid perovskites.
Extreme Toughening of Soft Materials with Liquid Metal
Authors: Kazem Navid , Bartlett Michael D. , Majidi Carmel
Published: April 2018

Soft and tough materials are critical for engineering applications in medical devices, stretchable and wearable electronics, and soft robotics. Toughness in synthetic materials is mostly accomplished by increasing energy dissipation near the crack tip with various energy dissipation techniques. However, bio‐materials exhibit extreme toughness by combining multi‐scale energy dissipation with the ability to deflect and blunt an advancing crack tip. Here, we demonstrate a synthetic materials architecture that also exhibits multi‐modal toughening, whereby embedding a suspension of micron sized and highly deformable liquid metal (LM) droplets inside a soft elastomer, the fracture energy dramatically increases by up to 50x (from 250 ± 50 J m‐2 to 11,900 ± 2600 J m‐2) over an unfilled polymer. For some LM‐embedded elastomer (LMEE) compositions, the toughness is measured to be 33,500 ± 4300 J m‐2, which far exceeds the highest value previously reported for a soft elastic material. This extreme toughening is achieved by (i) increasing energy dissipation, (ii) adaptive crack movement, and (iii) effective elimination of the crack tip. Such properties arise from the deformability of the LM inclusions during loading, providing a new mechanism to not only prevent crack initiation, but also resist the propagation of existing tears for ultra tough, soft materials.
FeS2 Nanoparticles Decorated Graphene as Microbial‐Fuel‐Cell Anode Achieving High Power Density
Authors: Wang Ruiwen , Yan Mei , Li Huidong , Zhang Lu , Peng Benqi , Sun Jinzhi , Liu Da , Liu Shaoqin
Published: April 2018

Microbial fuel cells (MFCs) have received great attention worldwide due to their potential in recovering electrical energy from waste and inexhaustible biomass. Unfortunately, the difficulty of achieving the high power, especially in real samples, remains a bottleneck for their practical applications. Herein, FeS2 nanoparticles decorated graphene is fabricated via a simple hydrothermal reaction. The FeS2 nanoparticles decorated graphene anode not only benefits bacterial adhesion and enrichment of electrochemically active Geobacter species on the electrode surface but also promotes efficient extracellular electron transfer, thus giving rise to a fast start‐up time of 2 d, an unprecedented power density of 3220 mW m−2 and a remarkable current density of 3.06 A m−2 in the acetate‐feeding and mixed bacteria‐based MFCs. Most importantly, the FeS2 nanoparticles decorated graphene anode successfully achieves a power density of 310 mW m−2 with simultaneous removal of 1319 ± 28 mg L−1 chemical oxygen demand in effluents from a beer factory wastewater. The characteristics of improved power generation and enhanced pollutant removal efficiency opens the door toward development of high‐performance MFCs via rational anode design for practical application.
Impact of High Valence State Cation Ti/Ta Surface Doping on the Stabilization of Spinel LiNi0.5Mn1.5O4 Cathode Materials: A Systematic Density Functional Theory Investigation
Authors: Chen Yuyang , Ben Liubin , Chen Bin , Zhao Wenwu , Huang Xuejie
Published: April 2018

Surface modification of a high‐voltage spinel LiNi0.5Mn1.5O4 cathode is a common method to improve its cycling performance for next generation lithium‐ion batteries, but the exact surface structural stabilization mechanism is not well‐understood. Here, detailed density function theory investigations based on the first‐principles calculations of high valence state Ti‐/Ta‐surface‐doped LiNi0.5Mn1.5O4 are reported. The migration of Ni/Mn ions is simulated into the surface structure of bare and Ti‐/Ta‐coated LiNi0.5Mn1.5O4. The calculation results suggest that Ti/Ta doping promotes Ni/Mn migration toward the formation of the rocksalt phase. Integrated net spin suggests that the valence state of transition metal ions, especially Ni, around Ti/Ta are slightly reduced in the fully charged state, resulting in a weakened surface oxidative property toward electrolyte. Both Ti/Ta doping and the consequent formation of the rocksalt phase not only stabilizes the oxygen frame of LiNi0.5Mn1.5O4 by forming stronger metal‐O bonds but also suppresses the oxygen evolution during cycling. The stabilized anion frame of oxygen further mitigates the dissolution of Mn ions from the lattice into the electrolyte. These computer simulations are in good accordance with experimental observations. The surface structural stabilization mechanism of the high valence state cation Ti‐/Ta‐coated LiNi0.5Mn1.5O4 can certainly be expanded to improve other cathode electrode materials.
Failure of Fermi Level in Referencing Chemical Shift of Molecules on Solid Surfaces
Authors: Li Yiying , Lu Zheng‐Hong
Published: April 2018

Core level chemical shifts using Fermi level as an orthodox reference level are extensively used to detect the forming/breaking of bonds (i.e., change in oxidation states) during chemical reactions and are broadly used as an experimental proof of charge transfers across organic interfaces by several research communities for many decades. Based on core level and valence photoemission experimental measurements a paradoxical relationship between core‐level shift and charge transfer is shown, demonstrating the failure of conventional practice of using Fermi level to measure chemical shifts of molecules on solid surfaces. Thus, great care needs to be taken when interpreting experimentally observed shifts in core level binding energies as well as assigning core level energy peaks associated with certain oxidation states. To resolve this paradoxical problem, it is shown that measurement of interface dipoles is essential in investigating the charge transfers of molecules to/from solid surfaces.
Lotus Seedpod Inspired SERS Substrates: A Novel Platform Consisting of 3D Sub‐10 nm Annular Hot Spots for Ultrasensitive SERS Detection
Authors: Jin Binbin , He Junhui , Li Jing , Zhang Yue
Published: April 2018

A novel lotus seedpod (LSP) like array substrate with tailorable annular nanogaps is reported for surface‐enhanced Raman spectroscopy (SERS). High SERS activity with excellent Raman signal reproducibility is achieved for molecular detection. Finite‐different time‐domain simulation suggests that sub‐10 nm annular nanogaps formed in the LSP array contribute significantly to the electromagnetic field enhancement for SERS measurements. The SERS substrate presents a detection limit as low as 10−12m along with a relative standard deviation as small as 4.1−8.0% in the detection of rhodamine 6G (R6G). Moreover, the linear correlation between Raman intensity and the concentration of R6G indicates the capability of the substrate for quantitative SERS analyses. As a typical example, the SERS substrate is successfully applied to detecting the α‐helical structure of amyloid‐β oligomers at a low concentration of 0.1 × 10−6m, which will be promising for label‐free detection of Alzheimer's disease in its earliest, presymptomatic, and most treatable stages. The as‐fabricated LSP array substrates therefore hold exciting potentials toward SERS‐based chemical and biomedical detections.
Tunable Photoluminescence Including White‐Light Emission Based on Noncovalent Interaction‐Locked N,N′‐Disubstituted Dihydrodibenzo[a,c]phenazines
Authors: Wang Jie , Yao Xuyang , Liu Yang , Zhou Haitao , Chen Wei , Sun Guangchen , Su Jianhua , Ma Xiang , Tian He
Published: April 2018

Utilizing supramolecular assembling system to achieve tunable photoluminescence emission has become an important method for the development of light‐emitting materials, which could bring out intriguing photophysical properties out of the luminophores themselves without a demanding design and tedious chemical synthesis. In the last few years, vibration‐induced emission (VIE) molecules, with dual photoluminescence emissions and large Stokes shift, have shown their talent in generating tunable fluorescence and potential in fabricating novel light‐emitting materials. However, little attention has been devoted to explore the attractive properties of VIE molecules in supramolecular self‐assembling systems up to now. Herein, the first example of a supramolecular assembling system composed of a water‐soluble VIE molecule N,N′‐diphenyl‐dihydrodibenzo[a,c]phenazines derivative (DPAC‐AB) and bis‐p‐sulfonatocalix[4]arene (BSC4) is introduced. Based on noncovalent interactions including hydrophobic interaction and host–guest interaction between DPAC‐AB and BSC4, tunable fluorescence emissions from orange‐red to white (Commission Internationale de L'éclairage (CIE) coordinates (0.32, 0.37)) to blue are achieved by simple addition of different amounts of BSC4 to the solution of DPAC‐AB. Additionally, a competitive guest acetylcholine is utilized to recover the nearly orange‐red fluorescence emission. This strategy to efficiently control the emission of VIE molecules through supramolecular assembling based on reversible noncovalent interactions opens new avenues in developing tunable light‐emitting materials.
A General and Robust Strategy for Fabricating Mechanoresponsive Surface Wrinkles with Dynamic Switchable Transmittance
Authors: Jiang Baolai , Liu Luntao , Gao Zongpeng , Wang Wenshou
Published: April 2018

Preparation of surface wrinkles on a skin layer/elastomer substrate bilayer film has attracted extensive attention because of their unique and broad applications in flexible electronic devices, tunable diffraction gratings, and smart windows. However, it still remains a great challenge to develop a general strategy for fabricating mechanoresponsive surface wrinkles using various skin layer materials with wide tunability of wrinkles' wavelength and amplitude, large optical modulation range, rapid optical switching rate, and high stability. Here, a general, simple, and cost‐effective strategy is reported, through uniaxially stretching and subsequently releasing skin layer/elastomer substrate bilayer films, for producing highly ordered, crack‐free, 1D surface wrinkles on elastomeric polydimethylsiloxane (PDMS) substrates with various skin layer materials, including polyvinyl alcohol (PVA), chitosan (CS), hydroxyethyl cellulose, and the mixtures of PVA and CS. The surface wrinkles on PVA/PDMS bilayer film exhibit excellent mechanoresponsive optical switching properties, such as large transmittance modulation range (transmittance from ≈6% to 91% at visible region), high optical sensitivity with small mechanical strain (less than 20%), and long optical switching cycles (over 2000 times). It is anticipated that this method will enable a new path to the fabrication of mechanoresponsive surface wrinkles with outstanding performance for applications in dynamic optical switching fields and beyond.
Evaluation of Natural and Synthetic Phosphate Donors for the Improved Enzymatic Synthesis of Phosphate Monoesters
Authors: Tasnádi Gábor , Jud Wolfgang , Hall Mélanie , Baldenius Kai , Ditrich Klaus , Faber Kurt
Published: April 2018

Undesired product hydrolysis along with large amounts of waste in form of inorganic monophosphate by‐product are the main obstacles associated with the use of pyrophosphate in the phosphatase‐catalyzed synthesis of phosphate monoesters on large scale. In order to overcome both limitations, we screened a broad range of natural and synthetic organic phosphate donors with several enzymes on a broad variety of hydroxyl‐compounds. Among them, acetyl phosphate delivered stable product levels and high phospho‐transfer efficiency at the lower functional pH‐limit, which translated into excellent productivity. The protocol is generally applicable to acid phosphatases and compatible with a range of diverse substrates. Preparative‐scale transformations using acetyl phosphate synthesized from cheap starting materials yielded multiple grams of various sugar phosphates with up to 433 g L−1 h−1 space‐time yield and 75% reduction of barium phosphate waste.

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Synthesis of Benzo[4,5]imidazo[2,1‐b]thiazole by Copper(II)‐Catalyzed Thioamination of Nitroalkene with 1H‐Benzo[d]imidazole‐2‐thiol
Authors: Jana Sourav , Chakraborty Amrita , Shirinian Valerii Z. , Hajra Alakananda
Published: April 2018

A Copper(II)‐catalyzed thioamination of β‐nitroalkene with 1H‐benzo[d]imidazole‐2‐thiol has been developed for the synthesis of benzo[4,5]imidazo[2,1‐b]thiazole derivatives. A variety of N‐fused benzoimidazothiazole derivatives are obtained in high yields through successive C−N and C−S bond formations. This protocol is also applicable to β‐substituted β‐nitroalkenes to afford 2,3‐disubstituted benzoimidazothiazoles.

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In situ polymerized poly(acrylic acid)/alumina nanocomposites for Pb2+ adsorption
Authors: Wang Ya‐Ping , Zhou Peng , Luo Shi‐Zhong , Guo Sijie , Lin Jing , Shao Qian , Guo Xingkui , Liu Zhongqing , Shen Jun , Wang Bin , Guo Zhanhu
Published: April 2018

In this study, two poly(acrylic acid)/alumina (PAA/alumina) nanocomposites with varied polymer loadings were prepared via in situ polymerization of preadsorbed acrylic acid. One composite would have a ~1/4‐monolayer polymer coverage, while the other had a ~2‐monolayer coverage. The produced composite materials were characterized in the adsorptive behavior of Pb2+ from aqueous solution. When there was less PAA produced in a nanocomposite sample, there was higher Pb2+ sorption capacity due to potentially less blocked alumina pores by in situ formed PAA. Isothermal and kinetic models for Pb2+ sorption were applied by considering the effects of the initial Pb2+ concentration and the contact time. The adsorption kinetics was best expressed using the pseudo‐second‐order equation. Through the isothermal studies, the maximum Pb2+ monolayer adsorption capacity of 167.79 mg/g was recorded for the composite with higher PAA loading.
Large Built‐In Fields Control the Electronic Properties of Nanoscale Molecular Devices with Dipolar Structures
Authors: Van Dyck Colin , Bergren Adam J.
Published: April 2018

Large area molecular junctions are nanoscale materials made of a molecular layer sandwiched between two metal electrodes. In this study, a fundamental property of these systems is demonstrated: the emergence of a large built‐in field, typically as high as 109 V m−1, and susceptible to appear in any junction possessing an asymmetry. This field originates from permanent dipoles in the contacted molecular layer and is responsible for a large renormalization of the band alignment in the junction. To illustrate this effect, a predictive theoretical characterization of two realistic gold‐thiolate‐based organic layers is carried out. The parameters leading to the emergence of the built‐in field are given and the very large renormalization effect is interpreted in terms of an applied voltage drop. Despite a high significance, this generic feature of molecular junctions has widely been neglected hitherto in the design and interpretation of molecular device characteristics. Built‐in fields provide a powerful way to achieve structure–property relationships in molecular junctions, by taking advantage of dipolar nanometric building blocks.