bluuebunny/crossref_metadata_2025_split huggingface dataset:
Good extrusion foaming performance of long‐chain branched PET induced by its enhanced crystallization property
Authors: Yao Shun , Guo Tianhao , Liu Tao , Xi Zhenhao , Xu Zhimei , Zhao Ling 
Published: March 2020

AbstractPoly(ethylene terephthalate) (PET) was modified by regulating different contents of branching agent epoxy‐based multifunctional oligomer and chain extender pyromellitic dianhydride in reactive extrusion process. The modified PET with better long‐chain branched (LCB) structure boosted its rheological properties, and its enhancement of melt viscoelasticity resulted in excellent foamability in molten‐state foaming process using supercritical CO2 as blowing agent. More importantly, the branched structures acted as crystal sites to accelerate the crystallization kinetic of LCB PET whether under atmospheric pressure or high‐pressure CO2. The shear and elongation flow inside die further quickly induced the crystallization of LCB PET. The rapidly generated fine crystals could both introduce heterogeneous cell nucleation and suppress CO2 escape, so the cell morphology of LCB PET in continuous extrusion foaming process exhibited a three‐fold increase in cell density and smaller uniform cell size with respect to those of other foam‐grade PET with long‐chain structure.
Optimized Fluorescent Probe for Specific Imaging of Glutathione S‐Transferases in Living Cells and Mice
Authors: Song Aiguo , Shen Xin , Feng Tian , Gai Shouchang , Wei Haiqing , Li Xinxin , Chen Hui 
Published: March 2020

AbstractGSTP1 has been considered to be a marker for malignancy in many tissues. However, the existing GST fluorescent probes are unfavorable for in vivo imaging because of the limited emission wavelength or insufficient fluorescence enhancement (six‐fold). The limited fluorescence enhancement of GST fluorescent probes is mainly ascribed to the high background signals resulting from the spontaneous reaction between GSH and the probes. In this work, a highly specific GST probe with NIR emission has been successfully developed through optimization of the essential unit of the probe to repress the spontaneous reaction. The novel GST probe exhibits over 100‐fold fluorescence enhancement upon incubation with GSTP1/GSH and high selectivity over other potential interference. In addition, the probe has been proved to be capable of tracking endogenous GST in A549 cells. Finally, the in vivo imaging results demonstrate that the probe can be used for effective imaging of endogenous GST activity in subcutaneous tumor mouse with high contrast.
Self‐Supported FeP‐CoMoP Hierarchical Nanostructures for Efficient Hydrogen Evolution
Authors: Wang Qin , Wang Zhiying , Zhao Yue , Li Fumin , Xu Ling , Wang Xiaoming , Jiao Huan , Chen Yu 
Published: March 2020

AbstractFabricating highly efficient electrocatalysts for electrochemical hydrogen generation is a top priority to relief the global energy crisis and environmental contamination. Herein, a rational synthetic strategy is developed for constructing well‐defined FeP−CoMoP hierarchical nanostructures (HNSs). In general terms, the self‐supported Co nanorods (NRs) are grown on conductive carbon cloth and directly serve as a self‐sacrificing template. After solvothermal treatment, Co NRs are converted into well‐ordered Co−Mo nanotubes (NTs). Subsequently, the small‐sized Fe oxyhydroxide nanorods arrays are hydrothermally grown on the surface of Co−Mo NTs to form Fe−Co−Mo HNSs, which are then converted into FeP−CoMoP HNSs through a facile phosphorization treatment. FeP−CoMoP HNSs display high activity for hydrogen evolution reaction (HER) with an ultralow cathodic overpotential of 33 mV at 10 mA cm−2 and a Tafel slope of 51 mV dec−1. Moreover, FeP−CoMoP HNSs also possess an excellent electrochemical durability in alkaline media. First‐principles density functional theory (DFT) calculations demonstrate that the remarkable HER activitiy of FeP−CoMoP HNSs originates from the synergistic effect between FeP and CoMoP.
Bimetal‐organic Framework‐derived Co9S8/ZnS@NC Heterostructures for Superior Lithium‐ion Storage
Authors: Duan Junfei , Wang Yongkang , Li Hongxing , Wei Donghai , Wen Fang , Zhang Guanhua , Liu Piao , Li Lingjun , Zhang Wei‐bing , Chen Zhaoyong 
Published: March 2020

AbstractHeterostructure engineering of electrode materials, which is expected to accelerate the ion/electron transport rates driven by a built‐in internal electric field at the heterointerface, offers unprecedented promise in improving their cycling stability and rate performance. Herein, carbon nanotubes with Co9S8/ZnS heterostructures embedded in a N‐doped carbon framework (Co9S8/ZnS@NC) have been rationally designed via an in‐situ vapor chemical transformation strategy with the aid of thiophene, which not only acted as carbon source for the growth of carbon nanotubes but also as sulfur source for the sulfurization of metal Zn and Co. Density functional theory (DFT) calculation shows an about 3.24 eV electrostatic potential difference between ZnS and Co9S8, which results in a strong electrostatic field across the interface that makes electrons transfer from Co9S8 to the ZnS side. As expected, a stable cycling performance with reversible capacity of 411.2 mAh g−1 at 1000 mA g−1 after 300 cycles, excellent rate capability (324 mAh g−1 at 2000 A g−1) and a high percentage of pseudocapacitance contribution (87.5% at 2.2 mv/s) for lithium‐ion batteries (LIBs) are achieved. This work provides a possible strategy for designing multicomponent heterostructural materials for application in energy storage and conversion fields.
Combining particle tracking microrheology and viscometry for the study of DNA aqueous solutions
Authors: Stefanopoulou Evdokia , Papagiannopoulos Aristeidis 
Published: March 2020

AbstractWe use video particle tracking microrheology (VPTMR) in order to investigate the viscoelasticity of salmon DNA and correlate it to its steady‐flow shear‐thinning viscosity. Aqueous solutions of DNA are tested in a wide concentration range from the dilute to the semidilute unentangled concentration regime. The observed mean squared displacement shows power‐law scaling with lag‐time which is equivalent to power‐law behavior of the complex modulus as a function of frequency that is, |G*(ω)| = S ∙ ω
α. The relaxation exponent
α changes abruptly with concentration in the semidilute regime from about 1 to about 0.5 which is the exponent predicted by the Rouse model. The quasi‐property
S follows the scaling of viscosity for uncharged polymers near θ‐conditions in the semidilute regime that is, with
νeff = 0.50 − 0.51. The shear‐thinning exponent observed by viscometry increases gradually towards the value of 0.5 which has been predicted for Rouse chains under flow. Our findings are in agreement with recent studies of DNA solutions where DNA is treated as a model polymer and addresses the low‐molar mass regime of DNA viscoelasticity. This work demonstrates that the combination of passive particle tracking with viscometry can provide a complete picture on the viscoelasticity of DNA‐based biopolymer materials.
High‐level production of 3‐hydroxypropionic acid from glycerol as a sole carbon source using metabolically engineered Escherichia coli
Authors: Kim Je Woong , Ko Yoo‐Sung , Chae Tong Un , Lee Sang Yup 
Published: March 2020

AbstractAs climate change is an important environmental issue, the conventional petrochemical‐based processes to produce valuable chemicals are being shifted toward eco‐friendly biological‐based processes. In this study, 3‐hydroxypropionic acid (3‐HP), an industrially important three carbon (C3) chemical, was overproduced by metabolically engineered Escherichia coli using glycerol as a sole carbon source. As the first step to construct a glycerol‐dependent 3‐HP biosynthetic pathway, the dhaB1234 and gdrAB genes from Klebsiella pneumoniae encoding glycerol dehydratase and glycerol reactivase, respectively, were introduced into E. coli to convert glycerol into 3‐hydroxypropionaldehyde (3‐HPA). In addition, the ydcW gene from K. pneumoniae encoding γ‐aminobutyraldehyde dehydrogenase, among five aldehyde dehydrogenases examined, was selected to further convert 3‐HPA to 3‐HP. Increasing the expression level of the ydcW gene enhanced 3‐HP production titer and reduced 1,3‐propanediol production. To enhance 3‐HP production, fed‐batch fermentation conditions were optimized by controlling dissolved oxygen (DO) level and employing different feeding strategies including intermittent feeding, pH‐stat feeding, and continuous feeding strategies. Fed‐batch culture of the final engineered E. coli strain with DO control and continuous feeding strategy produced 76.2 g/L of 3‐HP with the yield and productivity of 0.457 g/g glycerol and 1.89 g·L−1·h−1, respectively. To the best of our knowledge, this is the highest 3‐HP productivity achieved by any microorganism reported to date.
The role of intellectual and financial capital in competitiveness and performance: A study of emerging small and medium enterprises
Authors: Khattak Muhammad S. , Shah Syed Z. A. 
Published: March 2020

AbstractThe present research scrutinizes the influence of intellectual capital and financial capital (FC) on the small and medium enterprises' (SMEs) performance with a competitive advantage (CA) as a mediator. A plethora of research has been carried out to test the relationships among intellectual capital (IC), FC, and firm performance (FP) across the globe. However, studies on the CA as a mediator among these variables are rare in SMEs. Moreover, none of the studies of this landscape could be traced in developing countries particularly in Pakistan. This research examines the mediating role of CA between IC and FP as well as between FC and FP. A self‐administered survey was used to gather information from 178 registered ventures located in Rawalpindi and Islamabad Regions. The findings of this study display that IC and FC have a significant positive impact on the performance of SMEs, also significant and positive association exists between CA and FP. The path between IC and SMEs performance as well as between FC and SMEs performance is significantly mediated by the CA. The results recommend that SMEs should give attention to both IC and FC to sustain their position in the competitive markets.
The Selectivity of Fosfosal for STAT5b over STAT5a is Mediated by Arg566 in the Linker Domain
Authors: Gräb Julian , Berg Thorsten 
Published: March 2020

AbstractFosfosal is the O‐phosphorylated derivative of salicylic acid, with documented clinical use as a prodrug for the treatment of inflammatory diseases. We recently discovered that fosfosal itself inhibits the protein‐protein interaction domain, the SH2 domain, of the tumor‐related transcription factor STAT5b. Here, we demonstrate that fosfosal is selective for STAT5b over its close homologue STAT5a. This selectivity is mediated by the STAT5b residue Arg566, located in the SH2 domain‐adjacent linker domain. Our data provide further evidence for the role of the STAT linker domain in determining the activity of small molecules against the SH2 domain. We present a refined binding model for fosfosal and STAT5b, which can serve as the basis for the development of fosfosal‐based STAT5b inhibitors.
Optochemical Control of Protein Degradation
Authors: Wu Peng , Manna Debasish 
Published: March 2020

AbstractOptochemical approach has been successfully utilized to regulate cellular protein degradation with a high resolution of spatiotemporal control. In this highlight, we discuss two recent developments of combining reversible optochemical functionalities with the bifunctional proteolysis targeting chimeras, or PROTACs to achieve light‐controlled degradation of protein targets of interest. PHOTACs are azobeneze‐containing molecules that are inactive as trans forms and active as cis forms, switchable upon pulse‐irradiation with either an activating 390 nm light or a deactivating 525 nm light. In contrast, photoPROTACs are o‐F4‐azobenzene‐containing molecules that can be switched between active trans isomers and inactive cis isomers by a single irradiation event using 415 or 530 nm light. Combining these two optochemically controlled PROTAC systems has the potential to achieve orthogonal control on protein degradation.
Fluorophore‐Labeled Cyclic Nucleotides as Potent Agonists of Cyclic Nucleotide‐Regulated Ion Channels
Authors: Lelle Marco , Otte Maik , Bonus Michele , Gohlke Holger , Benndorf Klaus 
Published: March 2020

AbstractHigh‐affinity fluorescent derivatives of cyclic adenosine and guanosine monophosphate are powerful tools for investigating their natural targets. Cyclic nucleotide‐regulated ion channels belong to these targets and are vital for many signal transduction processes, such as vision and olfaction. The relation of ligand binding to activation gating is still challenging, and there is a need for fluorescent probes that enable the process to be broken down to the single‐molecule level. This inspired us to prepare fluorophore‐labeled cyclic nucleotides, which are composed of a bright dye and a nucleotide derivative with a thiophenol motif at position 8 that has already been shown to enable superior binding affinity. These bioconjugates were prepared by a novel cross‐linking strategy that involves substitution of the nucleobase with a modified thiophenolate in good yield. Both fluorescent nucleotides are potent activators of different cyclic nucleotide‐regulated ion channels with respect to the natural ligand and previously reported substances. Molecular docking of the probes excluding the fluorophore reveals that the high potency can be attributed to additional hydrophobic and cation‐π interactions between the ligand and the protein. Moreover, the introduced substances have the potential to investigate related target proteins, such as cAMP‐ and cGMP‐dependent protein kinases, exchange proteins directly activated by cAMP or phosphodiesterases.
Evaluation of Transport Phenomena for Removing Vanadium from Petrochemical Industry Solid Waste
Authors: Deniz Amanda Broska da Cruz , Valt Renata Bachmann Guimarães , Ponte Maria José Jerônimo de Santana , Ponte Haroldo de Araújo 
Published: March 2020

AbstractTransport phenomena are investigated which are involved in the electrokinetic remediation process used for removing vanadium from deactivated catalysts from oil catalytic cracking that are currently allotted to cement plants and class‐I landfills. Variables such as the concentration of electrolyte, electric potential, and applied electric current were evaluated in order to determine the effects produced by electroosmosis, diffusion, hydraulic gradient, and electromigration on the removal of vanadium from the catalyst. It was observed that migration is the most relevant phenomenon in the remediation tests, and for the best remediation condition, the migratory flow accounted for about 87 % of the vanadium removal.
Guest‐Dependent Pressure‐Induced Spin Crossover in FeII4[MIV(CN)8]2 (M=Mo, W) Cluster‐Based Material Showing Persistent Solvent‐Driven Structural Transformations
Authors: Jankowski Robert , Reczyński Mateusz , Chorazy Szymon , Zychowicz Mikołaj , Arczyński Mirosław , Kozieł Marcin , Ogorzały Karolina , Makowski Wacław , Pinkowicz Dawid , Sieklucka Barbara 
Published: March 2020

AbstractDiscrete molecular species that can perform certain functions in response to multiple external stimuli constitute a special class of multifunctional molecular materials called smart molecules. Herein, cyanido‐bridged coordination clusters {[FeII(2‐pyrpy)2]4[MIV(CN)8]2}⋅4 MeOH⋅6 H2O (M=Mo (1 solv), M=W (2 solv) and 2‐pyrpy=2‐(1‐pyrazolyl)pyridine are presented, which show persistent solvent driven single‐crystal‐to‐single‐crystal transformations upon sorption/desorption of water and methanol molecules. Three full desolvation–resolvation cycles with the concomitant change of the host molecules do not damage the single crystals. More importantly, the Fe4M2 molecules constitute a unique example where the presence of the guests directly affects the pressure‐induced thermal spin crossover (SCO) phenomenon occurring at the FeII centres. The hydrated phases show a partial SCO with approximately two out‐of‐four FeII centres undergoing a gradual thermal SCO at 1 GPa, while in the anhydrous form the pressure‐induced SCO effect is almost quenched with only 15 % of the FeII centres undergoing high‐spin to low‐spin transition at 1 GPa.
Amorphous/Crystalline Hetero‐Phase TiO2‐Coated α‐Fe2O3 Core–Shell Nanospindles: A High‐Performance Artificial Nitrogen Fixation Electrocatalyst
Authors: Qiu Weibin , Luo Yu‐Xi , Liang Ru‐Ping , Qiu Jian‐Ding 
Published: March 2020

AbstractElectrochemical nitrogen fixation techniques have emerged as a promisingly sustainable approach to face the challenge associated with nitrogen activation of ammonia synthesis by the Haber–Bosch process under ambient conditions. Herein, the performance of electrocatalytic nitrogen reduction for the production of α‐Fe2O3 nanospindles coated with mesoporous TiO2 with different crystallinity [denoted as α‐Fe2O3@mTiO2‐X (X=300, 400, and 500 °C)] were investigated. The as‐prepared α‐Fe2O3@mTiO2‐400 composite exhibits a large NH3 yield (27.2 μg h−1 mgcat.−1) at −0. 5 V vs. the reversible hydrogen electrode and a high Faradaic efficiency (13.3 %) in 0.1 m Na2SO4, with excellent electrochemical durability. This work presents a novel avenue for the rational design of efficient unique hetero‐phase nanocatalysts toward sustainable electrocatalytic N2 fixation.
Assessing Crystallisation Kinetics of Zr Metal–Organic Frameworks through Turbidity Measurements to Inform Rapid Microwave‐Assisted Synthesis
Authors: Griffin Sarah L. , Briuglia Maria L. , ter Horst Joop H. , Forgan Ross S. 
Published: March 2020

AbstractControlling the crystallisation of metal‐organic frameworks (MOFs), network solids of metal ions or clusters connected by organic ligands, is often hindered by the significant number of synthetic variables inherent to their synthesis. Coordination modulation, the addition of monotopic competing ligands to solvothermal syntheses, can allow tuning of physical properties (particle size, porosity, surface chemistry), enhance crystallinity, and select desired phases, by modifying the kinetics of self‐assembly, but its mechanism(s) are poorly understood. Herein, turbidity measurements were used to assess the effects of modulation on the solvothermal synthesis of the prototypical Zr terephthalate MOF UiO‐66 and the knowledge gained was applied to its rapid microwave synthesis. The studied experimental parameters—temperature, reagent concentration, reagent aging, metal precursor, water content, and modulator addition—all influence the time taken for onset of nucleation, and subsequently allow microwave synthesis of UiO‐66 in as little as one minute. The simple, low cost turbidity measurements align closely with previously reported in situ synchrotron X‐ray diffraction studies, proving their simplicity and utility for probing the nucleation of complex materials while offering significant insights to the synthetic chemist.
Multimeric Presentation of RGD Peptidomimetics Enhances Integrin Binding and Tumor Cell Uptake
Authors: Pina Arianna , Kadri Malika , Arosio Daniela , Dal Corso Alberto , Coll Jean‐Luc , Gennari Cesare , Boturyn Didier 
Published: March 2020

AbstractThe use of multimeric ligands is considered as a promising strategy to improve tumor targeting for diagnosis and therapy. Herein, tetrameric RGD (Arg‐Gly‐Asp) peptidomimetics were designed to target αvβ3 integrin‐expressing tumor cells. These compounds were prepared by an oxime chemoselective assembly of cyclo(DKP‐RGD) ligands and a cyclodecapeptide scaffold, which allows a tetrameric presentation. The resulting tetrameric RGD peptidomimetics were shown to improve αvβ3 integrin binding compared with the monomeric form. Interestingly, these compounds were also able to enhance tumor cell endocytosis in the same way as tetrameric RGD peptides. Altogether, the results show the potential of the tetrameric cyclo(DKP‐RGD) ligands for in vivo imaging and drug delivery.
Stereoselective Formation of Facial Tris‐Cyclometalated PtIV Complexes: Dual Phosphorescence from Heteroleptic Derivatives
Authors: López‐López Juan Carlos , Bautista Delia , González‐Herrero Pablo 
Published: March 2020

AbstractA stereoselective synthetic route to homo‐ and heteroleptic facial tris‐cyclometalated PtIV complexes is reported, involving the oxidative addition of 2‐(2‐pyridyl)‐ or 2‐(1‐isoquinolinyl)benzenediazonium salts to cis‐[Pt(C^N)2] precursors, with C^N=cyclometalated 2‐(p‐tolyl)pyridine (tpy), 2‐phenylquinoline (pq), 2‐(2‐thienyl)pyridine or 1‐phenylisoquinoline (piq), to produce labile diazenide intermediates that undergo photochemical or thermal elimination of N2. The method allows the preparation of derivatives bearing cyclometalated ligands of low π–π* transition energies. The new complexes exhibit phosphorescence in fluid solution at room temperature arising from triplet ligand‐centered (3LC) excited states, which, in the cases of the heteroleptic derivatives, involve the ligand with the lowest π–π* gap. The heteroleptic piq derivatives exhibit fluorescence and dual phosphorescence from different ligand‐centered excited states in rigid media, demonstrating the potential of cyclometalated PtIV complexes as multi‐emissive materials.
Dicht‐ und Klebstoffe auf Silikonbasis
Authors: Wolf Andreas T. 
Published: March 2020

ZusammenfassungAufgrund ihrer außergewöhnlichen Eigenschaften und den daraus resultierenden, vielseitigen Anwendungsmöglichkeiten sind Dicht‐ und Klebstoffe auf Silikonbasis mittlerweile aus unserem Alltag nicht mehr wegzudenken. Dieser Teil der Artikelserie diskutiert die physikalischen und chemischen Verfestigungsmechanismen, die den anwendungsfertigen Dicht‐ oder Klebstoff in das funktionsfähige Fugenmaterial überführen. Bei den elastischen Dicht‐ und Klebstoffen stehen für die Verfestigung verschiedene chemische Vernetzungsmechanismen zur Verfügung, die zum Teil auch untereinander kombiniert werden können. Dabei kann jeder dieser Vernetzungsmechanismen – Polykondensation, Polyaddition und radikalische Kettenreaktion – durch verschiedene Vernetzertypen realisiert werden. Dieses breite Repertoire an chemischen Reaktionen ermöglicht es, maßgeschneiderte Produkte für eine Vielzahl von Marktsegmenten und Anwendungen zu entwickeln.
Response surface optimization of the photocatalytic degradation of atenolol using immobilized graphene‐TiO2 composite
Authors: Bhatia Vibhu , Manoli Kyriakos , Dhir Amit , Ray Ajay K. 
Published: March 2020

AbstractPhotocatalytic processes using semiconductors have been widely explored due to their fascinating benefits in environmental remediation. In this study, a four‐factor three‐level Box‐Benkhen design (BBD) was employed to assess the photocatalytic degradation of atenolol (ATL) using immobilized graphene‐TiO2 as a photocatalyst. The four variables that were considered in the BBD model were the photocatalyst concentration (10%‐20%), pH (4‐9), ATL concentration (10‐30 mg/L), and light intensity (60‐260 W/m2). A monolithic‐type swirl‐flow reactor, which allowed the immobilization of the photocatalyst, was employed in a semi‐batch system to study the photocatalytic degradation kinetics of ATL. The optimum conditions where the highest rate constant (0.667 min−1) was observed were graphene‐TiO2 concentration of 10%, pH of 6.5, ATL concentration of 30 mg/L, and light intensity of 160 W/m2. The developed model well predicted the observed values indicated by a high R2 of 0.897. Reaction rate constants obtained herein using graphene‐TiO2 in immobilized form were compared with slurry system and TiO2.