bluuebunny/crossref_metadata_2025_split huggingface dataset:
Observation of the Low‐Frequency Spectrum of the Water Dimer as a Sensitive Test of the Water Dimer Potential and Dipole Moment Surfaces
Authors: Schwan Raffael , Qu Chen , Mani Devendra , Pal Nitish , van der Meer Lex , Redlich Britta , Leforestier Claude , Bowman Joel M. , Schwaab Gerhard , Havenith Martina 
Published: July 2019

AbstractUsing the helium nanodroplet isolation setup at the ultrabright free‐electron laser source FELIX in Nijmegen (BoHeNDI@FELIX), the intermolecular modes of water dimer in the frequency region from 70 to 550 cm−1 were recorded. Observed bands were assigned to donor torsion, acceptor wag, acceptor twist, intermolecular stretch, donor torsion overtone, and in‐plane and out‐of‐plane librational modes. This experimental data set provides a sensitive test for state‐of‐the‐art water potentials and dipole moment surfaces. Theoretical calculations of the IR spectrum are presented using high‐level quantum and approximate quasiclassical molecular dynamics approaches. These calculations use the full‐dimensional ab initio WHHB potential and dipole moment surfaces. Based on the experimental data, a considerable increase of the acceptor switch and a bifurcation tunneling splitting in the librational mode is deduced, which is a consequence of the effective decrease in the tunneling barrier.
Copper‐Catalyzed Asymmetric Annulation Reactions of Carbenes with 2‐Iminyl‐ or 2‐Acyl‐Substituted Phenols: Convenient Access to Enantioenriched 2,3‐Dihydrobenzofurans
Authors: Liang Xin‐Shen , Li Rui‐Dong , Wang Xiao‐Chen 
Published: July 2019

AbstractWe have developed a method for the highly diastereo‐ and enantioselective construction of 2,3‐dihydrobenzofurans bearing tetrasubstituted carbon stereocenters by means of annulation reactions between carbenes and 2‐iminyl‐ or 2‐acyl‐substituted phenols through catalysis by readily accessible copper(I)/bisoxazoline catalysts under mild conditions. These reactions feature a unique mechanism in which the copper catalyst serves a dual function: first it reacts with the diazo compound to generate a metal carbene, and second, upon formation of an oxonium ylide, it acts as a Lewis acid to activate the imine or ketone for diastereo‐ and enantioselective cyclization.
Kontrolle über Selbstassemblierung durch Ausnutzung von Koordinationsisomerie
Authors: Bäumer Nils , Kartha Kalathil K. , Allampally Naveen Kumar , Yagai Shiki , Albuquerque Rodrigo Q. , Fernández Gustavo 
Published: July 2019

AbstractHierin wird die inhärente geometrische Isomerie eines PtIIKomplexes als neues Werkzeug zur Kontrolle von supramolekularen Assemblierungsprozessen ausgenutzt. Bestrahlung mit UV‐Licht sowie die sorgfältige Auswahl des verwendeten Lösungsmittels, der Temperatur und Konzentration führen zu einer regelbaren Koordinationsisomerie. Dies ermöglicht ein vollständig reversibles Schalten zwischen zwei definierten aggregierten Spezies (1D Fasern ↔ 2D Lamellen) mit unterschiedlichem photoresponsivem Verhalten. Unsere Erkenntnisse erweitern nicht nur die Reichweite von Koordinationsisomerie, sondern eröffnen auch aufregende Möglichkeiten zur Entwicklung neuartiger stimuliresponsiver Materialien.
A μ‐Phosphido Diiron Dumbbell in Multiple Oxidation States
Authors: Ghosh Munmun , Cramer Hanna H. , Dechert Sebastian , Demeshko Serhiy , John Michael , Hansmann Max M. , Ye Shengfa , Meyer Franc 
Published: July 2019

AbstractThe reaction of the ferrous complex [LFe(NCMe)2](OTf)2 (1), which contains a macrocyclic tetracarbene as ligand (L), with Na(OCP) generates the OCP−‐ligated complex [LFe(PCO)(CO)]OTf (2) together with the dinuclear μ‐phosphido complex [(LFe)2P](OTf)3 (3), which features an unprecedented linear Fe‐(μ‐P)‐Fe motif and a “naked” P‐atom bridge that appears at δ=+1480 ppm in the 31P NMR spectrum. 3 exhibits rich redox chemistry, and both the singly and doubly oxidized species 4 and 5 could be isolated and fully characterized. X‐ray crystallography, spectroscopic studies, in combination with DFT computations provide a comprehensive electronic structure description and show that the Fe‐(μ‐P)‐Fe core is highly covalent and structurally invariant over the series of oxidation states that are formally described as ranging from FeIIIFeIII to FeIVFeIV. 3–5 now add a higher homologue set of complexes to the many systems with Fe‐(μ‐O)‐Fe and Fe‐(μ‐N)‐Fe core structures that are prominent in bioinorganic chemistry and catalysis.
Microenvironment Engineering of Ruthenium Nanoparticles Incorporated into Silica Nanoreactors for Enhanced Hydrogenations
Authors: Ren Xiaomin , Guo Miao , Li He , Li Chengbin , Yu Liang , Liu Jian , Yang Qihua 
Published: July 2019

AbstractIt is a challenging task to promote the activity and selectivity of a catalyst via precisely engineering the microenvironment, an important factor related with the catalytic performance of natural catalysts. Motivated by the water effect in promoting the catalytic activity explored in this work, a nanoreactor modified with phosphine ligand enabled the efficient hydrogenation of benzoic acid (BA) over Ru nanoparticles (NPs) in organic solvent under mild conditions, which cannot be achieved in unmodified nanoreactors. Both density functional theory (DFT) calculations and catalytic performance tests showed that the phosphine ligands can manipulate the adsorption strength of BA on Ru NPs by tuning the surface properties as well as preferentially interacting with the carboxyl of BA. The insights obtained in the present study provide a novel concept of nanoreactor design by anchoring ligands near catalytically active centers.
Exploiting Coordination Isomerism for Controlled Self‐Assembly
Authors: Bäumer Nils , Kartha Kalathil K. , Allampally Naveen Kumar , Yagai Shiki , Albuquerque Rodrigo Q. , Fernández Gustavo 
Published: July 2019

AbstractWe exploited the inherent geometrical isomerism of a PtIIcomplex as a new tool to control supramolecular assembly processes. UV irradiation and careful selection of solvent, temperature, and concentration leads to tunable coordination isomerism, which in turn allows fully reversible switching between two distinct aggregate species (1D fibers↔2D lamellae) with different photoresponsive behavior. Our findings not only broaden the scope of coordination isomerism, but also open up exciting possibilities for the development of novel stimuli‐responsive nanomaterials.
Biobased miktoarm star copolymer from soybean oil, isosorbide, and caprolactone
Authors: Teng Xiaoxu , Zhang Pei , Liu Tuan , Xin Junna , Zhang Jinwen 
Published: July 2019

ABSTRACTSoybean oil‐based macroinitiator was prepared from epoxidized soybean oil. A 1H NMR quantitative method was utilized for the characterization of this macroinitiator. A kind of renewable carbohydrate derivate, 1,4: 3,6‐Dianhydro‐D‐glucitol 2‐acrylate 5‐acetate (AAI) was prepared as the substitute monomer of styrene. Series of renewable miktoarm star copolymers initiated by soybean oil macroinitiator were obtained by atom transfer radical polymerization (ATRP) of AAI and ring‐opening polymerization (ROP) of ε‐caprolactone sequentially. The obtained miktoarm star block copolymers were characterized by 1H NMR, FTIR, and DSC. The DSC results show well dependence of the thermal behaviors of these miktoarm star block copolymers on the component of the two kinds of segments. A new strategy of renewable resource utilization has been provided on polymeric materials. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48281.
Amine‐impregnated natural zeolite as filler in mixed matrix membranes for CO2/CH4 separation
Authors: Castruita‐de León Griselda , Yeverino‐Miranda Claudia Y. , Montes‐Luna Angel de J. , Meléndez‐Ortiz Hector Iván , Alvarado‐Tenorio German , García‐Cerda Luis Alfonso 
Published: July 2019

ABSTRACTFlat mixed matrix membranes (MMMs) comprising polysulfone and clinoptilolite‐type natural zeolite were prepared by casting. Zeolite was modified with three alkylamines: ethanolamine (EA), bis(2‐hydroxypropyl)amine (BHPA), and polyethylenimine (PEI) by the impregnation method. Impregnated zeolite samples were characterized by X‐ray diffraction, Fourier transform infrared spectroscopy, and N2 adsorption–desorption. The alkylamine loading extent determined by thermogravimetric analysis was 5.2, 4.8, and 8.5% for EA, BHPA, and PEI, respectively. Analyses of MMMs showed that the incorporation of impregnated zeolite affected the glass‐transition temperature (Tg) and mixed‐gas transport properties. In this regard, a decreasing trend of the Tg values from 185.5 °C for the polymeric membrane up to 176.6 °C for Clino‐EA‐based MMM was recorded. In addition, the gas separation performance was evaluated at two different feed pressures. At 50 psi, MMMs showed an enhancement up to 30% on the CO2 permeability (22.79 Barrer) and 55% on the CO2/CH4 selectivity (45.78) in comparison with the polymeric membrane (CO2 permeability 17.34 Barrer; CO2/CH4 selectivity 29.38). These values varied depending on the alkylamine, BHPA being the most selective. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48286.
High‐efficiency preparation of polypropylene nanofiber by melt differential centrifugal electrospinning
Authors: Liu Yu‐Jian , Tan Jing , Yu Shao‐Yang , Yousefzadeh Maryam , Lyu Ting‐ting , Jiao Zhi‐Wei , Li Hao‐yi , Ramakrishna Seeram 
Published: July 2019

ABSTRACTMelt differential centrifugal electrospinning (MDCE) method is proposed by integrating the advantages of centrifugal spinning and melt differential electrospinning, including high efficiency, solvent‐free, multiple jets formation from nozzle‐less spinning system, and small diameter. A mathematical model of jet diameter in MDCE is established. An orthogonal experiment is carried out to explore the effects of main processing parameters on the average diameter and the diameter standard deviation of the prepared fibers. Ultimately, polypropylene (PP) nanofibers with an average diameter of 790 nm are successfully prepared in a higher flow rate of 124.26 g h−1 than that of other methods. The X‐ray diffraction and differential scanning calorimeter indicate that the introduction of high‐voltage electrostatic field in centrifugal spinning contribute to the crystal orientation of the PP molecular chain. Therefore, tensile mechanical strength is enhanced as the increase of the loading voltage. MDCE may provide an efficient and eco‐friendly method for nanofiber manufacturing in the future. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48299.
Dipeptidylpeptidase 4 as a Marker of Activated Fibroblasts and a Potential Target for the Treatment of Fibrosis in Systemic Sclerosis
Authors: Soare Alina , Györfi Hermina A. , Matei Alexandru E. , Dees Clara , Rauber Simon , Wohlfahrt Thomas , Chen Chih‐Wei , Ludolph Ingo , Horch Raymund E. , Bäuerle Tobias , von Hörsten Stephan , Mihai Carina , Distler Oliver , Ramming Andreas , Schett Georg , Distler Jörg H. W. 
Published: July 2019

ObjectiveExpression of dipeptidylpeptidase 4 (DPP‐4) identifies a dermal fibroblast lineage involved in scarring during wound healing. The role of DDP‐4 in tissue fibrosis is, however, unknown. The aim of the present study was to evaluate DPP‐4 as a potential target for the treatment of fibrosis in patients with systemic sclerosis (SSc).MethodsExpression of DPP‐4 in skin biopsy samples and dermal fibroblasts was analyzed by real‐time polymerase chain reaction, immunofluorescence, and Western blot analyses. The activity of DPP‐4 was modulated by overexpression, knockdown, and pharmacologic inhibition of DPP4 using sitagliptin and vildagliptin. The effects of DPP4 inhibition were analyzed in human dermal fibroblasts and in different mouse models of SSc (each n = 6).ResultsThe expression of DPP‐4 and the number of DPP‐4–positive fibroblasts were increased in the fibrotic skin of SSc patients, in a transforming growth factor β (TGFβ)–dependent manner. DPP‐4–positive fibroblasts expressed higher levels of myofibroblast markers and collagen (each P < 0.001 versus healthy controls). Overexpression of DPP4 promoted fibroblast activation, whereas pharmacologic inhibition or genetic inactivation of DPP4 reduced the proliferation, migration, and expression of contractile proteins and release of collagen (each P < 0.001 versus control mice) by interfering with TGFβ‐induced ERK signaling. DPP4‐knockout mice were less sensitive to bleomycin‐induced dermal and pulmonary fibrosis (P < 0.0001 versus wild‐type controls). Treatment with DPP4 inhibitors promoted regression of fibrosis in mice that had received bleomycin challenge and mice with chronic graft‐versus‐host disease, and ameliorated fibrosis in TSK1 mice (each P < 0.001 versus untreated controls). These antifibrotic effects were associated with a reduction in inflammation.ConclusionDPP‐4 characterizes a population of activated fibroblasts and shows that DPP‐4 regulates TGFβ‐induced fibroblast activation in the fibrotic skin of SSc patients. Inhibition of DPP4 exerts potent antifibrotic effects when administered in well‐tolerated doses. As DPP4 inhibitors are already in clinical use for diabetes, these results may have direct translational implications for the treatment of fibrosis in patients with SSc.
Sepiapterin Reductase Inhibition Leading to Selective Reduction of Inflammatory Joint Pain in Mice and Increased Urinary Sepiapterin Levels in Humans and Mice
Authors: Fujita Masahide , Scheffer Débora da Luz , Turnes Bruna Lenfers , Cronin Shane J. F. , Latrémolière Alban , Costigan Michael , Woolf Clifford J. , Latini Alexandra , Andrews Nick A. 
Published: July 2019

ObjectiveTo evaluate the antiinflammatory and analgesic effects of sepiapterin reductase (SPR) inhibition in a mouse model of inflammatory joint disease, and to determine whether urinary sepiapterin levels, as measured in mice and healthy human volunteers, could be useful as a noninvasive, translational biomarker of SPR inhibition/target engagement.MethodsThe collagen antibody–induced arthritis (CAIA) model was used to induce joint inflammation in mice. The effects of pharmacologic inhibition of SPR on thresholds of heat‐, cold‐, and mechanical‐evoked pain sensitivity and on signs of inflammation were tested in mice with CAIA. In addition, mice and healthy human volunteers were treated with SPR inhibitors, and changes in urinary sepiapterin levels were analyzed by high‐performance liquid chromatography.ResultsCAIA in mice was characterized by 2 phases: in the acute inflammation (early) phase, joint inflammation and heat‐, mechanical‐, and cold‐induced pain hypersensitivity were present, while in the postinflammation (late) phase, no joint inflammation was observed but heat‐ and mechanical‐induced hypersensitivity, but not cold hypersensitivity, were present. Inhibition of SPR in mice with CAIA significantly attenuated the heat‐induced hyperalgesia in both phases, and the mechanical allodynia in the late phase. Signs of inflammation were unaffected by SPR inhibition. Urinary tetrahydrobiopterin levels, as a marker of inflammatory pain, were increased during inflammation in mice with CAIA (2‐fold increase over controls; P < 0.05) and significantly reduced by SPR inhibition (P < 0.05 versus vehicle‐treated mice). Increased urinary sepiapterin levels in the presence of SPR inhibition in both mice and healthy human volunteers were associated with high sensitivity (70–85%) and high specificity (82–88%) for the prediction of SPR inhibition/target engagement.ConclusionSPR inhibition reduces the pain associated with joint inflammation, thus showing its potential utility as an analgesic strategy for inflammatory joint pain. In addition, SPR inhibition increases urinary sepiapterin levels, indicating the potential of this measurement as a noninvasive biomarker of target engagement of SPR inhibitors, such as sulfasalazine, a disease‐modifying antirheumatic drug that is currently used as a first‐line treatment for rheumatoid arthritis.
Lichenicidin rational site‐directed mutagenesis library: A tool to generate bioengineered lantibiotics
Authors: Barbosa Joana , Caetano Tânia , Mösker Eva , Süssmuth Roderich , Mendo Sónia 
Published: July 2019

AbstractLantibiotics are ribosomally synthesized and posttranslationally modified antimicrobial peptides that arise as an alternative to the traditional antibiotics. Lichenicidin is active against clinically relevant bacteria and it was the first lantibiotic to be fully produced in vivo in the Gram‐negative host Escherichia coli. Here, we present the results of a library of lichenicidin mutants, in which the mutations were generated based on the extensive bibliographical search available for other lantibiotics. The antibacterial activity of two‐peptide lantibiotics, as is lichenicidin, requires the synergistic activity of two peptides. We established a method that allows screening for bioactivity which does not require the purification of the complementary peptide. It is an inexpensive, fast and user‐friendly method that can be scaled up to screen large libraries of bioengineered two‐peptide lantibiotics. The applied system is reliable and robust because, in general, the results obtained corroborate structure–activity relationship studies carried out for other lantibiotics.
Reassessing the out‐of‐phase phenomenon in shake flasks by evaluating the angle‐dependent liquid distribution relative to the direction of the centrifugal acceleration
Authors: Azizan Amizon , Sieben Michaela , Wandrey Georg , Büchs Jochen 
Published: July 2019

AbstractShake flasks are still the most relevant experimental tool in the development of viscous fermentation processes. The phase number, which defines the onset of the unfavorable out‐of‐phase (OP) phenomenon in shake flasks, was previously defined via specific power input measurements. In the OP state, the bulk liquid no longer follows the orbital movement of the imposed centrifugal force, which is for example, detrimental to oxygen transfer. In this study, an optical fluorescence technique was used to measure the three‐dimensional liquid distribution in shake flasks. Four new optically derived evaluation criteria for the phase transition between the in‐phase and OP condition were established: (a) thickness of the liquid film left on the glass wall by the rotating bulk liquid, (b) relative slope of the leading edge of bulk liquid (LB) lines, (c) trend of the angular position of LB, and (d) very high angular position of the leading edge. In contrast to the previously applied power input measurements, the new optical evaluation criteria describe the phase transition in greater detailed. Instead of Ph = 1.26, a less conservative value of Ph = 0.91 is now suggested for the phase transfer, which implies a broader operating window for shake flask cultivations with higher viscosities.
A graph representation of functional diversity of brain regions
Authors: Yin Dazhi , Chen Xiaoyu , Zeljic Kristina , Zhan Yafeng , Shen Xiangyu , Yan Gang , Wang Zheng 
Published: July 2019

AbstractIntroductionModern network science techniques are popularly used to characterize the functional organization of the brain. A major challenge in network neuroscience is to understand how functional characteristics and topological architecture are related in the brain. Previous task‐based functional neuroimaging studies have uncovered a core set of brain regions (e.g., frontal and parietal) supporting diverse cognitive tasks. However, the graph representation of functional diversity of brain regions remains to be understood.MethodsHere, we present a novel graph measure, the neighbor dispersion index, to test the hypothesis that the functional diversity of a brain region is embodied by the topological dissimilarity of its immediate neighbors in the large‐scale functional brain network.ResultsWe consistently identified in two independent and publicly accessible resting‐state functional magnetic resonance imaging datasets that brain regions in the frontoparietal and salience networks showed higher neighbor dispersion index, whereas those in the visual, auditory, and sensorimotor networks showed lower neighbor dispersion index. Moreover, we observed that human fluid intelligence was associated with the neighbor dispersion index of dorsolateral prefrontal cortex, while no such association for the other metrics commonly used for characterizing network hubs was noticed even with an uncorrected p < .05.ConclusionsThis newly developed graph theoretical method offers fresh insight into the topological organization of functional brain networks and also sheds light on individual differences in human intelligence.
The prevalence, trends, and geographical distribution of human papillomavirus infection in China: The pooled analysis of 1.7 million women
Authors: Zhu Bo , Liu Yunyong , Zuo Tingting , Cui Xiaoli , Li Mengdan , Zhang Jing , Yu Huihui , Piao Haozhe 
Published: July 2019

AbstractHuman papillomavirus (HPV) infection which continues to be the most common sexually transmitted disease, has been identified as a major risk factor for cervical cancer. Therefore, it is very important to understand and grasp the distribution of HPV in Chinese population, and make the foundation for the development of cervical cancer vaccine in China. An extensive search strategy was conducted in multiple literature databases. All retrieved studies were screened by October 31, 2018. The prevalence of HPV infection was analyzed using random effects model. A total of 68 studies satisfied the inclusion criteria for our study. The national overall prevalence of HPV infection was 15.54% (95% CI: 13.83%‐17.24%). we also performed subgroup analysis by age, geographic location, level of economic development, HPV assay method, and type of HPV infection. The top 5 common HPV types detected in general population, were HPV 16 (3.52%, 95% CI: 3.18%‐3.86%), 52 (2.20%, 95% CI: 1.93%‐2.46%), 58 (2.10%, 95% CI: 1.88%‐2.32%), 18 (1.20%, 95% CI: 1.05%‐1.35%), and 33 (1.02%, 95% CI: 0.89%‐1.14%). Except for the higher prevalence of HPV infection in 2009 and 2010, the prevalence of HPV infection in other years changed little, ranged from 13.2% to 17.4%. HPV type in Chinese women was quite distinctive. HPV infection played a critical role in the occurrence of cervical cancer, understanding the distribution of HPV type and performing the HPV type testing had important clinical value for colposcopy referral and increasing the detection rate. Therefore, our findings could provide evidence for cervical cancer screening and vaccine, in order to reduce the burden of cervical cancer.