bluuebunny/crossref_metadata_2025_split huggingface dataset:
Poly(Glycerol Sebacate) in Biomedical Applications—A Review of the Recent Literature
Authors: Vogt Lena , Ruther Florian , Salehi Sahar , Boccaccini Aldo R. 
Published: March 2021

AbstractPoly(glycerol sebacate) (PGS) continues to attract attention for biomedical applications owing to its favorable combination of properties. Conventionally polymerized by a two‐step polycondensation of glycerol and sebacic acid, variations of synthesis parameters, reactant concentrations or by specific chemical modifications, PGS materials can be obtained exhibiting a wide range of physicochemical, mechanical, and morphological properties for a variety of applications. PGS has been extensively used in tissue engineering (TE) of cardiovascular, nerve, cartilage, bone and corneal tissues. Applications of PGS based materials in drug delivery systems and wound healing are also well documented. Research and development in the field of PGS continue to progress, involving mainly the synthesis of modified structures using copolymers, hybrid, and composite materials. Moreover, the production of self‐healing and electroactive materials has been introduced recently. After almost 20 years of research on PGS, previous publications have outlined its synthesis, modification, properties, and biomedical applications, however, a review paper covering the most recent developments in the field is lacking. The present review thus covers comprehensively literature of the last five years on PGS‐based biomaterials and devices focusing on advanced modifications of PGS for applications in medicine and highlighting notable advances of PGS based systems in TE and drug delivery.
Near‐Field Characterization of Higher‐Order Topological Photonic States at Optical Frequencies
Authors: Vakulenko Anton , Kiriushechkina Svetlana , Wang Mingsong , Li Mengyao , Zhirihin Dmitry , Ni Xiang , Guddala Sriram , Korobkin Dmitry , Alù Andrea , Khanikaev Alexander B. 
Published: March 2021

AbstractHigher‐order topological insulators (HOTIs) represent a new type of topological system, supporting boundary states localized over boundaries, two or more dimensions lower than the dimensionality of the system itself. Interestingly, photonic HOTIs can possess a richer physics than their original condensed matter counterpart, supporting conventional HOTI states based on tight‐binding coupling, and a new type of topological HOTI states enabled by long‐range interactions. Here, a new mechanism to establish all‐dielectric infrared HOTI metasurfaces exhibiting both types of HOTI states is proposed, supported by a topological transition accompanied by the emergence of topological Wannier‐type polarization. Two kinds of near‐field experimental studies are performed: i) the solid immersion spectroscopy and ii) near‐field imaging using scattering scanning near‐field optical microscopy to directly observe the topological transition and the emergence of HOTI states of two types. It is shown that the near‐field profiles indicate the displacement of the Wannier center across the topological transition leading to the topological dipole polarization and emergence of the topological boundary states. The proposed all‐dielectric HOTI metasurface offers a new approach to confine the optical field in micro‐ and nano‐scale topological cavities and thus paves the way to achieve a novel nanophotonic technology.
Porosimetry for Thin Films of Metal–Organic Frameworks: A Comparison of Positron Annihilation Lifetime Spectroscopy and Adsorption‐Based Methods
Authors: Stassin Timothée , Verbeke Rhea , Cruz Alexander John , Rodríguez‐Hermida Sabina , Stassen Ivo , Marreiros João , Krishtab Mikhail , Dickmann Marcel , Egger Werner , Vankelecom Ivo F. J. , Furukawa Shuhei , De Vos Dirk , Grosso David , Thommes Matthias , Ameloot Rob 
Published: March 2021

AbstractThin films of crystalline and porous metal–organic frameworks (MOFs) have great potential in membranes, sensors, and microelectronic chips. While the morphology and crystallinity of MOF films can be evaluated using widely available techniques, characterizing their pore size, pore volume, and specific surface area is challenging due to the low amount of material and substrate effects. Positron annihilation lifetime spectroscopy (PALS) is introduced as a powerful method to obtain pore size information and depth profiling in MOF films. The complementarity of this approach to established physisorption‐based methods such as quartz crystal microbalance (QCM) gravimetry, ellipsometric porosimetry (EP), and Kr physisorption (KrP) is illustrated. This comprehensive discussion on MOF thin film porosimetry is supported by experimental data for thin films of ZIF‐8.
Supramolecular Self‐Assembly‐Facilitated Aggregation of Tumor‐Specific Transmembrane Receptors for Signaling Activation and Converting Immunologically Cold to Hot Tumors
Authors: Li Jun , Fang Yuan , Zhang Yufan , Wang Huaimin , Yang Zhimou , Ding Dan 
Published: March 2021

AbstractSupramolecular self‐assembling peptide systems are attracting increasing interest in the field of cancer theranostics. Additionally, transformation of the immunologically cold tumor microenvironment into hot is of great importance for obtaining high antitumor responses for most immunotherapies. However, as far as it is known, there are nearly no studies on self‐assembling peptides reported to be able to convert cold to hot tumors. Herein, a self‐assembling peptide‐based cancer theranostic agent (named DBT‐2FFGYSA) is designed and synthesized, which can target tumor‐specific transmembrane Eph receptor A2 (EphA2) receptors selectively and make the receptors form large aggregates. Such aggregate formation promotes the cross‐phosphorylations among EphA2 receptors, leading to signal transduction of antitumor pathway. As a consequence, DBT‐2FFGYSA can not only visualize EphA2 receptors in a fluorescence turn‐on manner, but also specifically suppress the EphA2 receptor‐overexpressed cancer cell proliferation and tumor growth. What is more, DBT‐2FFGYSA also serves as an effective agent to convert immunologically cold tumors to hot by inducing the immunogenic cell death of EphA2 receptor‐overexpressed cancer cells and recruiting massive tumor‐infiltrating T cells. This study, thus, introduces a new category of agents capable of converting cold to hot tumors by pure supramolecular self‐assembly without any aid of known anticancer drugs.
Significantly Improving the Bioefficacy for Rheumatoid Arthritis with Supramolecular Nanoformulations
Authors: Ma Chao , Li Bo , Zhang Jinrui , Sun Yao , Li Jingjing , Zhou Hangcheng , Shen Jianlei , Gu Rui , Qian Jiangchao , Fan Chunhai , Zhang Hongjie , Liu Kai 
Published: March 2021

AbstractAs a typical inflammatory disease with chronic pain syndromes, rheumatoid arthritis (RA) generally requires long‐term treatment with frequent injection administration at 1–2 times per day, because common medications such as interleukin1 receptor antagonist (IL1ra) have poor bioavailability and very limited half‐life residence. Here a novel strategy to fabricate nanotherapeutic formulations employing genetically engineered IL1ra protein complexes, yielding ultralong‐lasting bioefficacy is developed rationally. Using rat models, it is shown that these nanotherapeutics significantly improved drug regimen to a single subcutaneous administration in a 14‐day therapy, suggesting their extraordinary bioavailability and ultralong‐acting pharmacokinetics. Specifically, the half‐life and bioavailability of the nanoformulations are boosted to the level of 30 h and by 7 times, respectively, significantly greater than other systems. This new strategy thus holds great promise to potently improve patient compliance in RA therapy, and it can be adapted for other therapies that suffer similar drawbacks.
Polyelectrolyte Substrate Coating for Controlling Biofilm Growth at Solid–Air Interface
Authors: Ryzhkov Nikolay V. , Nikitina Anna A. , Fratzl Peter , Bidan Cécile M. , Skorb Ekaterina V. 
Published: March 2021

AbstractBecause bacteria–surface interactions play a decisive role in bacteria adhesion and biofilm spreading, it is essential to understand how biofilms respond to surface properties to develop effective strategies to combat them. Polyelectrolyte coating is a simple and efficient way of controlling surface charge and energy. Using polyelectrolytes of various types, with different molecular weights and polyelectrolyte solutions of various pH provides a unique approach to investigate the interactions between biofilms and their substrate. Here, the formation of Escherichia coli biofilms at a solid–air interface is explored, whereby charge and interfacial energy are tuned using polyelectrolyte coatings on the surface. Cationic coatings are observed to limit biofilm spreading, which remain more confined when using high molecular weight polycations. Interestingly, biofilm surface densities are higher on polycationic surfaces despite their well‐studied bactericidal properties. Furthermore, the degree of polyelectrolyte protonation also appears to have an influence on biofilm spreading on polycation‐coated substrates. Finally, altering the interplay between biomass production and surface forces with polyelectrolyte coatings is shown to affect biofilm 3D architecture. Thereby, it is demonstrated that biofilm growth and spreading on a hydrogel substrate can be tuned from confined to expanded, simply by coating the surface using available polyelectrolytes.
Antenna Doping: The Key for Achieving Efficient Optical Wavelength Conversion in Crystalline Chromophoric Heterolayers
Authors: Haldar Ritesh , Chen Hongye , Mazel Antoine , Chen Dong‐Hui , Gupta Gaurav , Dua Navneet , Diring Stéphane , Odobel Fabrice , Wöll Christof 
Published: March 2021

AbstractHigh‐yield wavelength conversion is one of the key requirements for efficient photon energy harvesting. Attempts to realize efficient conversion by simply stacking layers of chromophores have failed so far, even when using highly crystalline assemblies and employing the recently discovered long‐range (>100 nm) Förster resonance energy transfer (LR‐FRET). Optical conversion efficiency is drastically improved using chromophoric metal–organic framework heterolayers fabricated layer‐by‐layer in connection with an “antenna doping” strategy. Systematic investigations reveal that the LR‐FRET mechanism, reported previously in chromophoric aggregates, is highly anisotropic for neat materials but can be made more isotropic by employing doping strategies. Using optimized fabrication parameters and dopant concentrations, a three‐layer, two‐step cascade with an overall optical conversion efficiency of ≈75% is realized.
Improved Long‐Term Stability and Reduced Humidity Effect in Gas Sensing: SiO2 Ultra‐Thin Layered ZnO Columnar Films
Authors: Postica Vasile , Lupan Oleg , Gapeeva Anna , Hansen Luka , Khaledialidusti Rasoul , Mishra Abhishek Kumar , Drewes Jonas , Kersten Holger , Faupel Franz , Adelung Rainer , Hansen Sandra 
Published: March 2021

AbstractThe undoped and metal‐doped zinc oxide columnar films (ZnO:Sn, ZnO:Fe, ZnO:Ag, and ZnO:Cu) are covered with an ultra‐thin layer of SiO2 (10–20 nm). The electrical, UV, and volatile organic compounds (VOCs) sensing properties are evaluated under different ambient conditions for ≈7 months to investigate the impact of the top SiO2‐layer on the long‐term stability of samples. The obtained results show a high immunity of sensing properties of SiO2‐coated samples to humidity. Furthermore, gas sensing measurements show that the loss in response after 203 days is significantly lower for coated samples indicating higher stability of sensing performance. For ZnO:Fe the gas response is reduced by about 90% after 203 days, but for SiO2‐coated ZnO:Fe columnar films the gas response is slightly reduced by only 38%. The density functional theory (DFT) calculations show that water species bind strongly with the surface SiO2 layer atoms with a −0.129 e− charge transfer, which is, much higher compared to the interaction with ethanol and acetone. Calculations show strong binding of water species on the SiO2 layer indicating preferential absorption of water molecules on SiO2. The obtained results demonstrate an important role of the top SiO2 ultra‐thin layer in order to produce humidity‐tolerant sensitive devices.
Multi‐Arm PEG/Peptidomimetic Conjugate Inhibitors of DR6/APP Interaction Block Hematogenous Tumor Cell Extravasation
Authors: Wang Liting , Shen Qing , Liao Hongze , Fu Hao , Wang Qi , Yu Jian , Zhang Wei , Chen Chuanrong , Dong Yang , Yang Xupeng , Guo Qianqian , Zhang Jiali , Zhang Jian , Zhang Wei , Lin Houwen , Duan Yourong 
Published: March 2021

AbstractThe binding of amyloid precursor protein (APP) expressed on tumor cells to death receptor 6 (DR6) could initiate the necroptosis pathway, which leads to necroptotic cell death of vascular endothelial cells (ECs) and results in tumor cells (TCs) extravasation and metastasis. This study reports the first inhibitor of DR6/APP interaction as a novel class of anti‐hematogenous metastatic agent. By rationally utilizing three combined strategies including selection based on phage display library, d‐retro‐inverso modification, and multiple conjugation of screened peptidomimetic with 4‐arm PEG, the polymer–peptidomimetic conjugate PEG‐tAHP‐DRI (tetra‐(D‐retro‐inverso isomer of AHP‐12) substitued 4‐arm PEG5k) is obtained as the most promising agent with the strongest binding potency (KD = 51.12 × 10−9 m) and excellent pharmacokinetic properties. Importantly, PEG‐tAHP‐DRI provides efficient protection against TC‐induced ECs necroptosis both in vitro and in vivo. Moreover, this ligand exhibits prominent anti‐hematogenous metastatic activity in serval different metastatic mouse models (B16F10, 4T1, CT26, and spontaneous lung metastasis of 4T1 orthotopic tumor model) and displays no apparent detrimental effects in preliminary safety evaluation. Collectively, this study demonstrates the feasibility of exploiting DR6/APP interaction to regulate hematogenous tumor cells transendothelial migration and provides PEG‐tAHP‐DRI as a novel and promising inhibitor of DR6/APP interaction for developments of anti‐hematogenous metastatic therapies.
Total Synthesis of Phenanthroviridin Aglycon and Its Analog
Authors: Akagi Yusuke , Harasawa Kohei , Komatsu Toshiya 
Published: March 2021

AbstractWe report the total synthesis of phenanthroviridin aglycon with interesting antibacterial and anticancer activities. A Pd‐catalyzed direct arylation of 5‐hydroxy‐1,4‐naphthoquinone with aryl iodides, which were prepared from 3,5‐dimethylphenol, gave aryl‐1,4‐naphthoquinones. Treatment of the resulting aryl‐1,4‐naphthoquinones with aqueous ammonia, followed by oxidative cyclization and deprotection, successfully yielded phenanthroviridin aglycon (1,8‐dihydroxy‐3‐methylbenzo[b]phenanthridine‐7,12‐dione) and its analog (1,11‐dihydroxy‐3‐methylbenzo[b]phenanthridine‐7,12‐dione).
Migration and maize in the Virú Valley: Understanding life histories through multi‐tissue carbon, nitrogen, sulfur, and strontium isotope analyses
Authors: Hyland Corrie , Millaire Jean‐François , Szpak Paul 
Published: March 2021

AbstractObjectivesStable isotope analysis can provide crucial insight into the function and development of early state‐level societies on the north coast of Peru.Materials and MethodsMulti‐tissue (bone collagen, tooth enamel, hair, nail, skin, and tendon) stable isotope analyses (carbon, nitrogen, sulfur, and strontium) were conducted for 13 individuals from the lower Virú Valley.ResultsNon‐seasonal changes in a predominantly C4‐based terrestrial diet, with minimal inputs of marine foods were identified. One individual (Burial 5), however, had a stable isotope signature unlike any previously found on the north coast of Peru, indicating both a large contribution of C3‐terrestrial resources to their diet and an 87Sr/86Sr value suggestive of highland residence during childhood.DiscussionThis research provides the first strong stable isotope evidence of a highland individual within a coastal burial in northern Peru, new insight into the ritual killing event at Huaca Santa Clara during the late middle horizon and supporting evidence of the importance of C4 terrestrial resources to the developing Virú polity during the early intermediate period.
Synthesis of walnut‐like polyaniline by using polyvinyl alcohol micellar template with excellent film transmission
Authors: Wang Wenjiao , Ma Yong , Zhuang Zhao , Zhou Shujie , Ma Mingliang , Wu Qi , Bai Ruiqin , Li Tingxi 
Published: March 2021

AbstractThough there have been many reports on various morphologies of polyaniline (PANI), the research on fabricating new morphologies remains to be explored. In this work, with the help of polyvinyl alcohol (PVA) micelles as templates, walnut‐like PANI having a rough periphery is successfully synthesized at room temperature by a static reaction. In addition, the effects of the amount of PVA, the concentration of HCl solution and the type of surfactant on the morphologies of PANI are studied in detail. Outcomes demonstrate that the fabrication of PANI walnuts is a result of the cooperation effect of the amount of PVA and the concentration of HCl solution. Moreover, PANI walnuts exhibit good thermal stability, which begins to degrade at up to about 300°C. Thin film coated by PANI walnuts possesses excellent transmittance. When PANI sample is prepared in the presence of 0.50 g PVA and 0.010 M HCl solution, the film transmittance can reach a maximum of 74% at 1200 nm. The sample presented herein have potential to be used in optical devices.
Hydrophilicity of electrospun microfibers of polyethylene oxide with semisoluble polyaniline for biological applications
Authors: Ramírez Rosario , Olayo Ma. Guadalupe , Palacios J. Cuauhtemoc , Flores Fernando G. , González Torres Maribel , Colín Orozco Elena , Valdivia Ricardo , Cruz Guillermo J. 
Published: March 2021

AbstractThis work studies the hydrophilicity of electrospun microfibers of polyaniline (PANI) synthesized by plasma combined with polyethylene oxide (PEO). The hydrophilicity was evaluated measuring the contact angles of water, phosphate‐buffered saline (PBS) and Krebs‐Ringer (KR) biological solutions formed on the polymers. Plasma PANI is usually insoluble due to the crosslinking associated with the electrical discharges of the synthesis conditions; however, PANI was synthesized as semi‐soluble films, which were dissolved and mixed with soluble PEO to obtain PANI/PEO electrospun microfibers. Super‐hydrophilic (<30°) angles were obtained with water on PEO fibers and hydrophobic (>90°) angles were obtained with the PBS solution on PANI/PEO fibers. PANI films had contact angles, which increased with the salts of KR and PBS solutions, PEO films had sudden increments and reductions with the saline solutions. PANI showed the typical chemical groups of polyanilines and others as CN and CC associated with a high dehydrogenation, which disappeared in PANI fibers. Electromagnetic absorption peaks in the 270–320 nm wavelength range were detected in the fibers and not in the films, which can be associated with transitions between benzoid and quinoid PANI structures. These results indicated that PANI/PEO fibers would not dissolve as rapidly as PEO fibers in biological solutions.
Conservation genetic assessment of the paleback darter, Etheostoma pallididorsum, a narrowly distributed endemic in the Ouachita Highlands, Arkansas, USA
Authors: McCall Brittany L. , Fluker Brook L. 
Published: March 2021

Abstract

The paleback darter, Etheostoma pallididorsum, is considered imperilled and has recently been petitioned for listing under the Endangered Species Act. Previous allozyme‐based studies found evidence of a small effective population size, warranting conservation concern. The objective of this study was to assess the population dynamics and the phylogeographical history of the paleback darter, using a multilocus microsatellite approach and mitochondrial DNA.
The predictions of this study were that: paleback darter populations will exhibit low genetic diversity and minimal gene flow; population structure will correspond to the river systems from which the samples are derived; reservoir dams impounding the reaches between the Caddo and Ouachita rivers would serve as effective barriers to gene flow; and the Caddo and Ouachita rivers are reciprocally monophyletic.
Microsatellite DNA loci revealed significant structure among sampled localities (global Fst = 0.17, P < 0.001), with evidence of two distinct populations representing the Caddo and Ouachita rivers. However, Bayesian phylogeographical analyses resulted in three distinct clades: Caddo River, Ouachita River, and Mazarn Creek. Divergence from the most recent ancestor shared among the river drainages was estimated at 60 Kya. Population genetic diversity was relatively low (He = 0.65; mean alleles per locus, A = 6.26), but was comparable with the population genetic diversity found in the close relatives slackwater darter, Etheostoma boschungi (He = 0.65; A = 6.74), and Tuscumbia darter, Etheostoma tuscumbia (He = 0.57; A = 5.53).
These results have conservation implications for paleback darter populations and can be informative for other headwater specialist species. Like other headwater species with population structuring and relatively low genetic diversity, the persistence of paleback darter populations is likely to be tied to the persistence and connectivity of local breeding and non‐breeding habitat. These results do not raise conservation concern for a population decline; however, the restricted distribution and endemic status of the species still renders paleback darter populations vulnerable to extirpation or extinction.
Insight into the Multistate Emissive N, P‐doped Carbon Nano‐Onions: Emerging Visible‐Light Absorption for Photocatalysis
Authors: Kar Subhajit , Bramhaiah Kommula , John Neena S. , Bhattacharyya Santanu 
Published: March 2021

AbstractCarbon dots (CDs) have become one of the most emerging materials as an alternative solar light‐induced photocatalyst in contrast to traditional metal‐based systems. However, one of the major challenges is the lack of visible light absorption. Herein, we have fabricated unique N, P‐co‐doped CDs with a self‐assembled onion‐like layered structure by using a bottom‐up facile synthesis technique from chitosan gel and phosphoric acid as molecular precursors. This typical layered structure of N, P‐co‐doped carbon nano onions (N, P‐CNOs), with an average size of 25–50 nm, displays an enhanced visible light absorption. Detailed structural and elemental characterizations confirm the extensive aromatic domain with P‐containing surface functionalities, while electrochemical study clarifies the lowering of band gaps as well as the creation of new electronic states in comparison to the pristine N‐CDs. Furthermore, the intrinsic structural features are correlated with the underpinning photophysical processes by steady‐state and time‐resolved fluorescence spectroscopy. In addition, steady‐state polarized emission and thermo‐responsive PL properties have been carried out to unveil further the structure‐property correlation of N, P‐CNOs, and their comparative study with pristine N‐CDs at the different excitation wavelengths. Finally, N, P‐CNOs exhibit efficient visible‐light‐induced photocatalysis, and the detailed mechanistic study is carried out by trapping the photogenerated species in an aqueous medium. The prepared N, P‐CNOs displayed an excellent visible‐light photocatalytic performance over MB dye with a degradation efficiency of 75.8% within 120 min along with a degradation rate constant of ∼0.0109 min−1. It is concluded that the easy to synthesize and low‐cost N, P‐CNOs with a unique morphology hold great potential for application in visible‐light photocatalysis.