bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chirality Enhancement of Porphyrin Supramolecular Assembly Driven by a Template Preorganization Effect
Authors: Gaeta Massimiliano , Raciti Domenica , Randazzo Rosalba , Gangemi Chiara M. A. , Raudino Antonio , D'Urso Alessandro , Fragalà Maria E. , Purrello Roberto 
Published: June 2018

AbstractCationic polylysine promotes, under neutral conditions, the spontaneous aggregation of opposite charged ZnTPPS in water. Spectroscopic investigations evidence a different preorganization of ZnTPPS onto the polypeptide matrix depending on the chain length. Spinodal decomposition theory in confined geometry is used to model this mechanism by considering the time evolution of a homogeneous distribution of randomly adsorbed particles (porphyrins) onto a rodlike polyelectrolyte (polymer) of variable length L.
Enhanced production of poly‐γ‐glutamic acid by improving ATP supply in metabolically engineered Bacillus licheniformis
Authors: Cai Dongbo , Chen Yaozhong , He Penghui , Wang Shiyi , Mo Fei , Li Xin , Wang Qin , Nomura Christopher T. , Wen Zhiyou , Ma Xin , Chen Shouwen 
Published: June 2018

AbstractPoly‐γ‐glutamic acid (γ‐PGA) is an important multifunctional biopolymer with various applications, for which adenosine triphosphate (ATP) supply plays a vital role in biosynthesis. In this study, the enhancement of γ‐PGA production was attempted through various approaches of improving ATP supply in the engineered strains of Bacillus licheniformis. The first approach is to engineer respiration chain branches of B. licheniformis, elimination of cytochrome bd oxidase branch reduced the maintenance coefficient, leading to a 19.27% increase of γ‐PGA yield. The second approach is to introduce Vitreoscilla hemoglobin (VHB) into recombinant B. licheniformis, led to a 13.32% increase of γ‐PGA yield. In the third approach, the genes purB and adK in ATP‐biosynthetic pathway were respectively overexpressed, with the AdK overexpressed strain increased γ‐PGA yield by 14.69%. Our study also confirmed that the respiratory nitrate reductase, NarGHIJ, is responsible for the conversion of nitrate to nitrite, and assimilatory nitrate reductase NasBC is for conversion of nitrite to ammonia. Both NarGHIJ and NasBC were positively regulated by the two‐component system ResD–ResE, and overexpression of NarG, NasC, and ResD also improved the ATP supply and the consequent γ‐PGA yield. Based on the above individual methods, a method of combining the deletion of cydBC gene and overexpression of genes vgB, adK, and resD were used to enhance ATP content of the cells to 3.53 μmol/g of DCW, the mutant WX‐BCVAR with this enhancement produced 43.81 g/L of γ‐PGA, a 38.64% improvement compared to wild‐type strain WX‐02. Collectively, our results demonstrate that improving ATP content in B. licheniformis is an efficient strategy to improve γ‐PGA production.
Vascularized microfluidic platforms to mimic the tumor microenvironment
Authors: Michna Rhys , Gadde Manasa , Ozkan Alican , DeWitt Matthew , Rylander Marissa 
Published: June 2018

AbstractMicrofluidic technology has led to the development of advanced in vitro tumor platforms that overcome the challenges of in vivo animal and in vitro two dimensional models. This paper presents platform designs and methods used to develop complex vascularized in vitro models to mimic the tumor microenvironment. Features of these platforms include a continuous, aligned endothelium that allows for cell‐cell interactions between vasculature and tumor cells. A novel platform for fabrication of a single endothelialized microchannel encased within a collagen platform hosting breast cancer cells was developed and utilized to study the influence of cellular interaction on transport phenomenon through vasculature in a hyperpermeable tumor microenvironment. This platform relies on subtractive tissue engineering fabrication techniques. Through confocal imaging we have demonstrated that the platform produces enhanced vessel leakiness recapitulating physiological features of the tumor microenvironment. The influence of tumor endothelial interactions on transport of particles was also demonstrated. Additionally, we designed two more complex and intricate endothelialized microfluidic networks by combining lithographic techniques with additive tissue engineering methods. We created a network platform consisting of interconnected microchannels to model a highly vascularized system and successfully perfused the system with fluorescent particles. Finally, we developed a physiologically representative in vitro microfluidic platform with vasculature patterned from in vivo data showing the versatility of these systems to replicate the complex geometries of tumor microvasculature and dynamically measured particle transport. Overall, we have shown the ability to develop functional microfluidic vascular tumor platforms of varying complexities and demonstrated their utility for studying spatial particle transport within these systems.
Segmental bone replacement via patient‐specific, three‐dimensional printed bioresorbable graft substitutes and their use as templates for the culture of mesenchymal stem cells under mechanical stimulation at various frequencies
Authors: Chung Rebecca , Kalyon Dilhan M. , Yu Xiaojun , Valdevit Antonio 
Published: June 2018

AbstractThe treatment of large segmental bone defects remains a challenge as infection, delayed union, and nonunion are common postoperative complications. A three‐dimensional printed bioresorbable and physiologically load‐sustaining graft substitute was developed to mimic native bone tissue for segmental bone repair. Fabricated from polylactic acid, this graft substitute is novel as it is readily customizable to accommodate the particular size and location of the segmental bone of the patient to be replaced. Inspired by the structure of the native bone tissue, the graft substitute exhibits a gradient in porosity and pore size in the radial direction and exhibit mechanical properties similar to those of the native bone tissue. The graft substitute can serve as a template for tissue constructs via seeding with stem cells. The biocompatibility of such templates was tested under in vitro conditions using a dynamic culture of human mesenchymal stem cells. The effects of the mechanical loading of cell‐seeded templates under in vitro conditions were assessed via subjecting the tissue constructs to 28 days of daily mechanical stimulation. The frequency of loading was found to have a significant effect on the rate of mineralization, as the alkaline phosphatase activity and calcium deposition were determined to be particularly high at the typical walking frequency of 2 Hz, suggesting that mechanical stimulation plays a significant role in facilitating the healing process of bone defects. Utilization of such patient‐specific and biocompatible graft substitutes, coupled with patient’s bone marrow cells seeded and exposed to mechanical stimulation of 2 Hz have the potential of reducing significant volumes of cadaveric tissue required, improving long‐term graft stability and incorporation, and alleviating financial burdens associated with delayed or failed fusions of long bone defects.
Covalent Chemical Cochaperones of the p300/CBP GACKIX Domain
Authors: Lodge Jean M. , Majmudar Chinmay Y. , Clayton James , Mapp Anna K. 
Published: June 2018

AbstractThe GACKIX activator binding domain has been a compelling target for small‐molecule probe discovery because of the central role of activator–GACKIX complexes in diseases ranging from leukemia to memory disorders. Additionally, GACKIX is an ideal model to dissect the context‐dependent function of activator–coactivator complexes. However, the dynamic and transient protein–protein interactions (PPIs) formed by GACKIX are difficult targets for small molecules. An additional complication is that activator‐binding motifs, such as GACKIX, are found in multiple coactivators, making specificity difficult to attain. In this study, we demonstrate that the strategy of tethering can be used to rapidly discover highly specific covalent modulators of the dynamic PPIs between activators and coactivators. These serve as both ortho‐ and allosteric modulators, enabling the tunable assembly or disassembly of the activator–coactivator complexes formed between the KIX domain and its cognate activator binding partners MLL and CREB. The molecules maintain their function and selectivity, even in human cell lysates and in bacterial cells, and thus, will ultimately be highly useful probes for cellular studies.
Sodium Aminotroponiminates: Ligand‐Induced Disproportionation, Mixed‐Metal Compounds, and Exceptional Activity in Polymerization Catalysis
Authors: Hanft Anna , Jürgensen Malte , Bertermann Rüdiger , Lichtenberg Crispin 
Published: June 2018

AbstractSodium complexes of aminotroponiminate (ATI) ligands have been reacted with a range of neutral donor ligands. Upon addition of crown ethers, they undergo an unusual ligand‐induced disproportionation reaction with formation of [Na(ATI)2]− sodiate complex anions. The same structural motif has also been found in the first well‐defined mixed‐metal ATI complexes, which have been accessed starting from monometallic sodium and potassium species. The mixed‐metal compounds confirm the possibility of ATIs to act as ditopic ligands. Using the polymerization of ϵ‐caprolactone as a model system, structure‐reactivity‐relationships in sodium and mixed‐metal ATI compounds have been studied by comparing the reactivity of [Na(ATI)] and [Na(ATI)2]− structural motifs. These studies revealed trends in the catalyst activity depending on the nuclearity of the complex and the substitution pattern at the ATI ligand. Exceptionally high activities were obtained for dinuclear sodium sodiates of type [Na(crown)2][Na(ATI)2], making them the most active alkali metal initiators for this reaction. The organometallic and polymeric compounds presented in this work have been characterized by techniques including (VT‐)NMR spectroscopy, single‐crystal X‐ray diffraction, gel permeation chromatography, mass spectrometry, and DFT calculations.
Effects of Temperature on the Filtration Characteristics of a Dual‐Layer Granular Bed Filter
Authors: Shen Wei-Jie , Yang Guo-Hua , Liu Peng , Yao Zhi-Wei , Shi Hua-Jie , Cui Yu-Yong , Li Zhen 
Published: June 2018

AbstractThe effects of temperature on the filtration efficiency and pressure drop of a dual‐layer granular bed filter were investigated in a hot dual‐layer granular bed filter with experimental dust. Enhanced higher filtration efficiency was obtained with higher filtration temperature, and the removal efficiency of ultrafine dust was also at a high level. Simultaneously, the total pressure drop maintained at an acceptable range. The results demonstrate that the dual‐layer granular bed has excellent prospects for application to low‐temperature coal pyrolysis.
Overcoming the Inertness of Iridium(III) in a Facile Single‐Crystal to Single‐Crystal Reaction of Iodine Vapor with a Cyclometalated Chloride Monomer
Authors: Bezzubov Stanislav I. , Kalle Paulina , Bilyalova Alfiya A. , Tatarin Sergei V. , Dolzhenko Vladimir D. 
Published: June 2018

AbstractIridium(III) is often considered to be one of the most inert octahedral metal ions. Herein we present a phenanthroimidazole‐based bis‐cyclometalated iridium(III) chloride undergoing a facile chloro ligand exchange with iodine, in a gas‐solid reaction under ambient conditions. Monitoring the progress of the reaction by X‐ray diffraction analysis reveals the crystal‐packing‐induced exceptional stereoselectivity of this topochemical transformation. The results provide excellent opportunities to modulate the geometry and kinetic properties of cyclometalated iridium(III) complexes that may be very promising in catalysis and design of anticancer agents.
A Novel Sc(OTf)3‐Catalyzed (2+2+1)‐Cycloannulation/Aza‐Friedel–Crafts Alkylation Sequence toward Multicyclic 2‐Pyrrolines
Authors: Schlegel Marcel , Coburger Peter , Schneider Christoph 
Published: June 2018

AbstractThe rapid assembly of molecular complexity continues to be at the forefront of novel reaction development. In the pursuit of that goal, we herein report a novel Sc(OTf)3‐catalyzed, one‐pot multicomponent reaction that furnishes complex multicyclic 2‐pyrrolines with excellent overall yields and perfect diastereocontrol. This process is based on our previously established (2+2+1)‐cycloannulation of in situ generated 1‐azaallyl cations, 1,3‐dicarbonyls and primary amines. The newly formed and highly reactive aminal moiety is readily substituted with indoles and pyrroles both as external and internal π‐nucleophiles to provide densely functionalized N‐heterocycles with four new σ‐bonds and two vicinal quaternary stereogenic centers. In addition, DFT calculations have been conducted to further characterize the intermediate 1‐azaallyl cations.
Luminescence from Lanthanide(III) Ions Bound to the Glycocalyx of Chinese Hamster Ovary Cells
Authors: Arppe‐Tabbara Riikka , Carro‐Temboury Miguel R. , Hempel Casper , Vosch Tom , Sørensen Thomas Just 
Published: June 2018

AbstractLanthanide(III) ions bind to the glycocalyx of Chinese Hamster Ovary (CHO) cells and give rise to a unique luminescent fingerprint. Following direct excitation of terbium(III) and europium(III) ions in the visible part of the spectrum, we are able to collect emission spectra pixel‐by‐pixel in images of CHO cells. Following data analysis that removes the background signal, the fine structure of the europium(III) luminescence indicate that the lanthanide(III) ions are bound to a single structure of the CHO cell glycocalyx. This was deduced from the fact that the structure‐sensitive emission spectrum of europium is unchanged throughout the investigated samples.
Realizing the Potential of Acetylenedicarboxylate by Functionalization to Halofumarate in ZrIV Metal–Organic Frameworks
Authors: Ma Ntep Tobie J. Matemb , Reinsch Helge , Moll Bastian , Hastürk Emrah , Gökpinar Serkan , Breitzke Hergen , Schlüsener Carsten , Schmolke Laura , Buntkowsky Gerd , Janiak Christoph 
Published: June 2018

AbstractA strategy was developed to obtain from acetylenedicarboxylic acid either an acetylenedicarboxylate‐based ZrIV metal–organic framework (MOF) with fcu topology or a halo‐functionalized‐MOF‐801 through in situ ligand hydrohalogenation. The new materials feature exceptionally high hydrophilicity and CO2/H2 adsorption energetics. The acetylenedicarboxylate linker and its functionalizable triple‐bond discloses its potential in the engineering of microporous materials with targeted properties.
Designing Deep‐UV Birefringent Crystals by Cation Regulation
Authors: Zhang Zhizhong , Wang Ying , Zhang Bingbing , Yang Zhihua , Pan Shilie 
Published: June 2018

AbstractTwo new alkaline earth metal fluorooxoborates, CaB4O6F2 and SrB4O6F2, have been synthesized and characterized. The title compounds are isostructural and crystallize in centrosymmetric space group P
(No. 2). Structurally, the fundamental building blocks, B4O8F2 groups, are connected by B−O bonds to form [B4O6F2]∞ layers, which stack parallelly along the c axis. In addition, BaB4O6F2, a known fluorooxoborate with different crystal structure, was also synthesized and characterized for comparison. The cation size influence on the structure of this MB4O6F2 (M=Ca, Sr, Ba) family is discussed in detail. The diffuse‐reflectance spectroscopy measurements indicate that the cutoff edges of title compounds are below 190 nm. Moreover, first‐principle calculation results demonstrate that MB4O6F2 (M=Ca, Sr, Ba) have large birefringence of 0.091, 0.089, and 0.085 at 1064 nm. Both experimental and theoretical studies suggest that MB4O6F2 (M=Ca, Sr, Ba) are promising birefringent materials for deep‐UV applications.
Are Sc—C and Sc—P Bonds Reactive in Scandium Phosphinoalkylidene Complex? Insights on a Versatile Reactivity
Authors: Mao Weiqing , Xiang Li , Lamsfus Carlos Alvarez , Maron Laurent , Leng Xuebing , Chen Yaofeng 
Published: June 2018

AbstractThe peculiar electronic structure of scandium phosphinoalkylidene complex [LSc{C(SiMe3)PPh2}THF] (L=[MeC(NDIPP)CHC(NDIPP)Me]−), DIPP=2,6‐(iPr)2C6H3) leads to an interesting versatile reactivity, which is demonstrated both experimentally and computationally. The complex undergoes [2+2] cycloaddition reactions with alkynes, and easily activates various X—O bonds such as C—O of propylene oxide, N—O of 3,5‐dimethylisoxazole, B—O of pinacolborane and Si—O of triethoxysilane. These reactions occur on the Sc—C bond of the phosphinoalkylidene complex. Interestingly, the Sc—P bond can also be activated as the presence of a Sc—C—P three center π interaction in the complex allows performing C—F activation of 2,6‐difluoropyridine and 1,2 addition with imine or ketone. The complex also reacts with metal complexes, [(COD)RhCl]2 and (Ph3P)AuCl, to form structural intriguing heterobimetallic complexes.
The basal interstitial nucleus (BIN) of the cerebellum provides diffuse ascending inhibitory input to the floccular granule cell layer
Authors: Jaarsma Dick , Blot Francois G. C. , Wu Bin , Venkatesan Subramanian , Voogd Jan , Meijer Dies , Ruigrok Tom J. H. , Gao Zhenyu , Schonewille Martijn , De Zeeuw Chris I. 
Published: June 2018

AbstractThe basal interstitial nucleus (BIN) in the white matter of the vestibulocerebellum has been defined more than three decades ago, but has since been largely ignored. It is still unclear which neurotransmitters are being used by BIN neurons, how these neurons are connected to the rest of the brain and what their activity patterns look like. Here, we studied BIN neurons in a range of mammals, including macaque, human, rat, mouse, rabbit, and ferret, using tracing, immunohistological and electrophysiological approaches. We show that BIN neurons are GABAergic and glycinergic, that in primates they also express the marker for cholinergic neurons choline acetyl transferase (ChAT), that they project with beaded fibers to the glomeruli in the granular layer of the ipsilateral floccular complex, and that they are driven by excitation from the ipsilateral and contralateral medio‐dorsal medullary gigantocellular reticular formation. Systematic analysis of codistribution of the inhibitory synapse marker VIAAT, BIN axons, and Golgi cell marker mGluR2 indicate that BIN axon terminals complement Golgi cell axon terminals in glomeruli, accounting for a considerable proportion ( > 20%) of the inhibitory terminals in the granule cell layer of the floccular complex. Together, these data show that BIN neurons represent a novel and relevant inhibitory input to the part of the vestibulocerebellum that controls compensatory and smooth pursuit eye movements.
High‐Quality Yeast‐2‐Hybrid Interaction Network Mapping
Authors: Altmann Melina , Altmann Stefan , Falter Claudia , Falter‐Braun Pascal 
Published: June 2018

AbstractIn this article, we describe a Y2H interaction mapping protocol for systematically screening medium‐to‐large collections of open reading frames (ORFs) against each other. The protocol is well suited for analysis of focused networks, for modules of interest, assembling genome‐scale interactome maps, and investigating host‐microbe interactions. The four‐step high‐throughput protocol has a demonstrated low false‐discovery rate that is essential for producing meaningful network maps. Following the assembly of yeast expression clones from an existing ORFeome collection, we describe in detail the four‐step procedure that begins with the primary screen using minipools, followed by secondary verification of primary positives, identification of candidate interaction pairs by sequencing, and a final verification step using fresh inoculants. In addition to this core protocol, aspects of network mapping and quality control will be discussed briefly. © 2018 by John Wiley & Sons, Inc.
Growth, condition, and maturity schedules of an estuarine fish species change in estuaries following increased hypoxia due to climate change
Authors: Cottingham Alan , Huang Peisheng , Hipsey Matthew R. , Hall Norman G. , Ashworth Eloise , Williams Joel , Potter Ian C. 
Published: June 2018

AbstractUnderstanding challenges posed by climate change to estuaries and their faunas remains a high priority for managing these systems and their communities. Freshwater discharge into a range of estuary types in south‐western Australia between 1990 and 2015 is shown to be related to rainfall. This largely accounts for decreases in discharge in this microtidal region being more pronounced on the west coast than south coast, where rainfall decline was less. Results of an oxygen‐balance model imply that, as demonstrated by empirical data for the Swan River Estuary, declines in discharge into a range of estuary types would be accompanied by increases in the extent of hypoxia. In 2013–15, growth and body condition of the teleost Acanthopagrus butcheri varied markedly among three permanently open, one intermittently‐open, one seasonally‐closed and one normally‐closed estuary, with average time taken by females to reach the minimum legal length (MLL) of 250 mm ranging from 3.6 to 17.7 years. It is proposed that, in a given restricted period, these inter‐estuary variations in biological characteristics are related more to differences in factors, such as food resources and density, than to temperature and salinity. The biological characteristics of A. butcheri in the four estuaries, for which there are historical data, changed markedly between 1993–96 and 2013–15. Growth of both sexes, and also body condition in all but the normally‐closed estuary, declined, with females taking between 1.7 and 2.9 times longer to attain the MLL. Irrespective of period, body condition, and growth are positively related. Age at maturity typically increased between periods, but length at maturity declined only in the estuary in which growth was greatest. The plasticity of the biological characteristics of A. butcheri, allied with confinement to its natal estuary and ability to tolerate a wide range of environmental conditions, makes this sparid and comparable species excellent subjects for assessing estuarine “health.”
Rethinking the importance of the structure of ecological networks under an environment‐dependent framework
Authors: Cenci Simone , Song Chuliang , Saavedra Serguei 
Published: June 2018

AbstractA major quest in network and community ecology has been centered on understanding the importance of structural patterns in species interaction networks—the synthesis of who interacts with whom in a given location and time. In the past decades, much effort has been devoted to infer the importance of a particular structure by its capacity to tolerate an external perturbation on its structure or dynamics. Here, we demonstrate that such a perspective leads to inconsistent conclusions. That is, the importance of a network structure changes as a function of the external perturbations acting on a community at any given point in time. Thus, we discuss a research agenda to investigate the relative importance of the structure of ecological networks under an environment‐dependent framework. We hypothesize that only by studying systematically the link between network structure and community dynamics under an environment‐dependent framework, we can uncover the limits at which communities can tolerate environmental changes.