bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radical Cascade Bicyclization/Aromatization of 1,7‐Enynes with 1,3‐Dicarbonyl Compounds towards 2,3‐Dihydro‐1H‐cyclopenta[a]naphthalenes
Authors: Cai Tao , Zhang Zhebing , Li Peiqin , Sun Tao , Chen Xinyu , Ni Yuqi , Chen Jianhui , Xu Huiting , Xu Yanfei , Wu Chunlei , Shen Runpu , Gao Yuzhen 
Published: June 2021

AbstractAn Ag‐catalyzed radical cascade bicyclization/aromatization of C‐linked 1,7‐enynes with 1,3‐dicarbonyls has been achieved, providing a step‐ and atom‐economy approach for the construction of 2,3‐dihydro‐1H‐cyclopenta[a]naphthalenes, an important structural scaffold existed in biologically active compounds. From this transformation, structurally diverse 2,3‐dihydro‐1H‐cyclopenta[a]naphthalenes were obtained in moderate to good yields with high regioselectivity. Moreover, the further product derivatizations were also exemplified.magnified image
Which impeller should be chosen for efficient solid–liquid mixing in the laminar and transitional regime?
Authors: Delacroix Bastien , Fradette Louis , Bertrand François , Blais Bruno 
Published: June 2021

AbstractThe vast majority of solid–liquid mixing studies have focused on high Reynolds number applications with configurations and impeller geometries adapted to this type of regime. However, the mixing of particles in a viscous fluid is an essential element of many contemporary industries. We used the computational fluid dynamics‐discrete element method model previously developed in our group to investigate solid–liquid mixing with close‐clearance impellers in the laminar regime of operation. We compared different geometries, that is, the double helical ribbon, anchor, Paravisc™, and Maxblend™ impellers. We investigated the impact of fluid viscosity and compared the results with those obtained with the pitched blade turbine, a more commonly used impeller, based on power consumption for equivalent mixing states. This study highlights that the higher the viscosity of the fluid, the more interesting it is to use close‐clearance impellers for their ability to generate a strong shear stress and a strong bulk flow in the entire vessel.
Fruit evolution in Hydrophyllaceae
Authors: Vasile Maria‐Anna , Luebert Federico , Jeiter Julius , Weigend Maximilian 
Published: June 2021

PremiseFruit type and morphology are tightly connected with angiosperm diversification. In Boraginales, the first‐branching families, including Hydrophyllaceae, have one‐ to many‐seeded capsules, whereas most of the remaining families have four‐seeded indehiscent fruits. This fact argues for many‐seeded capsules as the ancestral condition. However, little is known about the evolution of fruit dehiscence and seed number. The present study investigated the gynoecium and fruit development and morphology and the evolution of seed‐numbers in Hydrophyllaceae.MethodsGynoecium and fruit development and morphology were studied using scanning electron microscopy and x‐ray microcomputed tomography. Ancestral character state reconstruction of seed number was performed using a broadly sampled phylogeny of Boraginales (ndhF and ITS) with an emphasis on Hydrophyllaceae.ResultsOur ontogenetic studies not only demonstrate parallel developmental trajectories across Hydrophyllaceae, but also a striking diversity regarding the internal organization of the gynoecium. Ovule number appears to determine ovary structure. Many‐seeded capsules are retrieved as the ancestral state of Hydrophyllaceae. At least seven transitions to fruits with (one to) four seeds and four reversals (i.e., from four‐ to many‐seeded fruits) were reconstructed in Hydrophyllaceae.ConclusionsSeveral shifts in seed number from “many” to “four” and back to “many” have taken place in capsular‐fruited Hydrophyllaceae, a strikingly high number considering that seed number is virtually conserved across the rest of the order. The groups with a conserved seed number of four are characterized by indehiscent schizocarps or drupes and by seeds that are integrated into mericarps. This functional integration probably acts as an evolutionary constraint to shifts in seed number.
Investigating genetic diversity in admixed populations from Ecuador
Authors: Flores‐Espinoza Rodrigo , Paz‐Cruz Elius , Ruiz‐Pozo Viviana A. , Lopez‐Carrera Marcelo , Cabrera‐Andrade Alejandro , Gusmão Leonor , Burgos German 
Published: June 2021

AbstractObjectivesAccording to demographic history, Ecuador has experienced shifts in its Native American populations caused by European colonization and the African slave trade. The continuous admixture events among Europeans, Native Americans, and Africans occurred differently in each region of the country, producing a stratified population. Thus, the aim of this study was to investigate the level of genetic substructure in the Ecuadorian Mestizo population.Materials and methodsA total of 377 male and 209 female samples were genotyped for two sets of X‐chromosomal markers (32 X‐Indels and 12 X‐STRs). Population analyses performed included Hardy–Weinberg equilibrium tests, LD analysis, PCA, pairwise FSTs, and AMOVA.ResultsSignificant levels of LD were observed between markers separated by distances of less than 1 cM, as well as between markers separated by distances varying from 10.891 to 163.53 cM. Among Ecuadorian regions, Amazonia showed the highest average R2 value.DiscussionWhen X‐chromosomal and autosomal differentiation values were compared, a sex‐biased admixture between European men and Native American and African women was revealed, as well as between African men and Native American women. Moreover, a distinct Native American ancestry was discernible in the Amazonian population, in addition to sex‐biased gene flow between Amazonia and the Andes and Pacific coast regions. Overall, these results underline the importance of integrating X chromosome information to achieve a more comprehensive view of the genetic and demographic histories of South American admixed populations.
Thiophen‐basierte konjugierte acetylenische Polymere mit dualen aktiven Zentren für effiziente Cokatalysator‐freie photoelektrochemische Wasserreduktion im alkalischen Medium
Authors: Borrelli Mino , Querebillo Christine Joy , Pastoetter Dominik L. , Wang Tao , Milani Alberto , Casari Carlo , Khoa Ly Hoang , He Fan , Hou Yang , Neumann Christof , Turchanin Andrey , Sun Hanjun , Weidinger Inez M. , Feng Xinliang 
Published: June 2021

AbstractKonjugierte Polymere sind attraktive Materialien für die photoelektrochemische Wasserstoffentwicklungsreaktion (PEC‐HER) unter neutralen oder sauren Bedingungen. Jedoch zeigen sie im alkalischen Medium immer noch eine geringe PEC‐HER‐Leistung aufgrund des Fehlens von Wasserdissoziations‐Zentren. Hier zeigen wir, dass durch Anpassung des konjugierten acetylenischen Polymers (CAPs) von Poly(diethinylthieno[3,2‐b]thiophen) (pDET) zu Poly(2,6‐diethinylbenzo[1,2‐b:4,5‐b′]dithiophen (pBDT) und Poly(diethinyldithieno[3,2‐b:2′,3′‐d]thiophen) (pDTT) hocheffiziente aktive Wasserdissoziations‐Zentren in CAPs eingeführt werden können. Infolgedessen zeigen auf Cu‐Substrat gewachsene pDTT und pBDT Benchmark‐Photostromdichten von 170 μA cm−2 und 120 μA cm−2 (bei 0,3 V vs. RHE; pH 13), die 4,2‐ bzw. 3‐mal höher sind als die von pDET. DFT‐Rechnungen und elektrochemische Operando‐Resonanz‐Raman‐Spektroskopie zeigen, dass die elektronenangereicherten Cβ der äußeren Thiophenringe von pDTT die aktiven Zentren für die Wasserdissoziation sind, während die ‐C≡C‐Bindungen als aktive Zentren für die Wasserstoffentwicklung fungieren.
Nanoscale Chemical Imaging of Supported Lipid Monolayers using Tip‐Enhanced Raman Spectroscopy
Authors: Pandey Yashashwa , Kumar Naresh , Goubert Guillaume , Zenobi Renato 
Published: June 2021

AbstractVisualizing the molecular organization of lipid membranes is essential to comprehend their biological functions. However, current analytical techniques fail to provide a non‐destructive and label‐free characterization of lipid films under ambient conditions at nanometer length scales. In this work, we demonstrate the capability of tip‐enhanced Raman spectroscopy (TERS) to probe the molecular organization of supported DPPC monolayers on Au (111), prepared using the Langmuir–Blodgett (LB) technique. High‐quality TERS spectra were obtained, that permitted a direct correlation of the topography of the lipid monolayer with its TERS image for the first time. Furthermore, hyperspectral TERS imaging revealed the presence of nanometer‐sized holes within a continuous DPPC monolayer structure. This shows that a homogeneously transferred LB monolayer is heterogeneous at the nanoscale. Finally, the high sensitivity and spatial resolution down to 20 nm of TERS imaging enabled reproducible, hyperspectral visualization of molecular disorder in the DPPC monolayers, demonstrating that TERS is a promising nanoanalytical tool to investigate the molecular organization of lipid membranes.
From Kinase Inhibitors to Multitarget Ligands as Powerful Drug Leads for Alzheimer's Disease using Protein‐Templated Synthesis
Authors: Nozal Vanesa , García‐Rubia Alfonso , Cuevas Eva P. , Pérez Concepción , Tosat‐Bitrián Carlota , Bartolomé Fernando , Carro Eva , Ramírez David , Palomo Valle , Martínez Ana 
Published: June 2021

AbstractMultitarget directed ligands (MTDLs) are arising as promising tools to tackle complex diseases. The main goal of this work is to create powerful modulating agents for neurodegenerative disorders. To achieve this aim, we have combined fragments that inhibit key protein kinases involved in the main pathomolecular pathways of Alzheimer's disease (AD) such as tau aggregation, neuroinflammation and decreased neurogenesis, whilst looking for a third action in beta‐secretase (BACE1), responsible of β‐amyloid production. We obtained well‐balanced MTDLs with in vitro activity in three different relevant targets and efficacy in two cellular models of AD. Furthermore, computational studies confirmed how these compounds accommodate adequately into the long and rather narrow BACE1 catalytic site. Finally, we employed in situ click chemistry using BACE1 as protein template as a versatile synthetic tool that allowed us to obtain further MTDLs.
Das Kupfer‐Chaperon NosL bildet ein Heterometallzetrum für die Cu‐Abgabe an Distickstoffmonoxid‐Reduktase
Authors: Prasser Benedikt , Schöner Lisa , Zhang Lin , Einsle Oliver 
Published: June 2021

AbstractDer letzte Schritt der Denitrifikation ist die Reduktion von Lachgas (N2O) zu N2, die durch die Cu‐abhängige Distickstoffmonoxid‐Reduktase (N2OR) vermittelt wird. Ihre Metallzentren, CuA und CuZ, werden durch die sequenzielle Bereitstellung von zwölf CuI‐Ionen durch ein Metall‐Chaperon assembliert, das Teil eines nos‐Genclusters ist, der das Enzym und seine akzessorischen Faktoren kodiert. Bei dem Chaperon handelt es sich um das nosL‐Genprodukt, ein 18 kDa Lipoprotein, von dem man annimmt, dass es sich in der äußeren Membran Gram‐negativer Bakterien befindet. Um den Zusammenbau von N2OR besser zu verstehen, haben wir NosL aus Shewanella denitrificans hergestellt und die Struktur des metallbeladenen Chaperons mittels Röntgenkristallographie bestimmt. Das Protein assembliert ein heterodinukleares Metallzentrum, bestehend aus ZnII und CuI, wie durch anomale Röntgenstreuung nachgewiesen werden konnte. Während nur CuI an das Enzym geliefert wird, ist die stabilisierende Anwesenheit von ZnII essentiell für die Funktionalität und strukturelle Integrität des Chaperons.
The Copper Chaperone NosL Forms a Heterometal Site for Cu Delivery to Nitrous Oxide Reductase
Authors: Prasser Benedikt , Schöner Lisa , Zhang Lin , Einsle Oliver 
Published: June 2021

AbstractThe final step of denitrification is the reduction of nitrous oxide (N2O) to N2, mediated by Cu‐dependent nitrous oxide reductase (N2OR). Its metal centers, CuA and CuZ, are assembled through sequential provision of twelve CuI ions by a metallochaperone that forms part of a nos gene cluster encoding the enzyme and its accessory factors. The chaperone is the nosL gene product, an 18 kDa lipoprotein predicted to reside in the outer membrane of Gram‐negative bacteria. In order to better understand the assembly of N2OR, we have produced NosL from Shewanella denitrificans and determined the structure of the metal‐loaded chaperone by X‐ray crystallography. The protein assembled a heterodinuclear metal site consisting of ZnII and CuI, as evidenced by anomalous X‐ray scattering. While only CuI is delivered to the enzyme, the stabilizing presence of ZnII is essential for the functionality and structural integrity of the chaperone.
Boosting Photocatalytic Water Oxidation Over Bifunctional Rh0‐Rh3+ Sites
Authors: Liu Yuanwei , Wang Li Jie , Zhang Hao , Yuan Hai Yang , Zhang Qinghua , Gu Lin , Wang Hai Feng , Hu P. , Liu Peng Fei , Jiang Zheng , Yang Hua Gui 
Published: June 2021

AbstractPhotocatalytic water splitting provides an economically feasible way for converting solar energy into hydrogen. Great efforts have been devoted to developing efficient photocatalysts; however, the surface catalytic reactions, especially for the sluggish oxygen evolution reaction (OER), still remain a challenge, which limits the overall photocatalytic energy efficiency. Herein, we design a Rhn cluster cocatalyst, with Rh0‐Rh3+ sites anchoring the Mo‐doped BiVO4 model photocatalytic system. The resultant photocatalyst enables a high visible‐light photocatalytic oxygen production activity of 7.11 mmol g−1 h−1 and an apparent quantum efficiency of 29.37 % at 420 nm. The turnover frequency (TOF) achieves 416.73 h−1, which is 378 times higher than that of the photocatalyst only with Rh3+ species. Operando X‐ray absorption characterization shows the OER process on the Rh0‐Rh3+ sites. The DFT calculations further illustrate a bifunctional OER mechanism over the Rh0‐Rh3+ sites, in which the oxygen intermediate attacks the Rh3+ sites with assistance of a hydrogen atom transfer to the Rh0 sites, thus breaking the scaling relationship of various oxygen intermediates.
Effect of Ce doping on the catalytic performance of xNiCeOy@SiO2 catalysts for dry reforming of methane
Authors: Lu Yao , Wang Ruilei , Zhao Yujun , Wang Shengping , Ma Xinbin 
Published: June 2021

AbstractA series of xNiCeOy@SiO2 catalysts with different cerium contents were prepared by hydrothermal coprecipitation and Stöber method. The results of catalytic performance showed that 15NiCeOy@SiO2 has the best catalytic activity with the methane conversion of 81.1% and the specific activity of the catalyst (the amount of methane converted per mol Ni per minute) of 1.14. 10NiCeOy@SiO2 exhibits the highest stability, with the methane conversion remaining unchanged within 40 h. Compared with the undoped Ni@SiO2 catalyst, the enhancement of the activity can be attributed to the reduction of the Ni particle size due to the doping of Ce, which enabled more exposure of active species. Meanwhile, the oxygen vacancies originating from extrinsic defects of ceria increase the reaction rate of activated carbon and CO2, inhibit carbon deposition, and accelerate the structure stability.
Effect of the interphase properties on the fracture energy and fatigue behavior of thermoset resins containing spherical fillers
Authors: Khezri Jamal , Rash‐Ahmadi Samrand , Alizadeh Kaklar Javad 
Published: June 2021

AbstractInterphase region in polymer based nanocomposites is a very thin layer that is created between the reinforcing phase and the matrix surface due to reaction forces between the nanoparticles and the matrix. The ability to determine the behavior of the interphase region can facilitate the understanding and prediction of the fracture toughness and fatigue behavior through multiscale modeling. In the present study, by using the fully analytical multiscale hierarchical modeling method, fracture toughness and also fatigue behavior of thermoset resins containing spherical fillers with consideration the influences of the main damage mechanisms and interphase properties (thickness and elastic modulus of the interphase region) were investigated. The novelty of this investigation is that it enables the application of a range of properties to the interphase zone and describes a technique for multiscale modeling based on this interphase zone. The present multiscale approach quantifies the dissipation energy due to main damage mechanisms at the nanoscale and accounts for the emergence of an interphase region as functionally graded (FG) properties surrounding nanofillers. Modeling of FG interphase power‐varying properties, the derivation of governing equations, and the evaluation of the findings, all are parts of the achievements of this research. In addition, multiscale analyses have been carried out on fracture energy and fatigue behavior in various fiber volume fractions with and without interphase properties. It was found that the fracture toughness and fatigue behavior are significantly dependent on the interphase elastic properties and thickness. Furthermore, the critical debonding stress and the fracture energy were assessed with various interfacial fracture energy, elastic modulus, and thickness of interphase. Finally, the accuracy of the utilized multiscale approach with consideration of interphase properties was verified by comparing the modeling results with experimental tests on thermoset resins containing spherical fillers.
Molecular dynamics simulation for investigating and assessing reaction conditions between carboxylated polyethersulfone and polyethyleneimine
Authors: Rahmati Mahmoud , Rajabzadeh Saeid , Abdelrasoul Amira , Kawabata Yuki , Yoshioka Tomohisa , Matsuyama Hideto , Mohammadi Toraj 
Published: June 2021

AbstractRecently, nano‐filtration membranes are made by the reaction between a reactive functional group on the surface of a tight ultrafiltration membrane and a charged branched polymer. This reaction makes the selective layer of the nanofiltration membrane, which plays an essential role in membrane performance. A molecular dynamics simulation with a reactive force field was used to investigate the reaction of carboxylated polyethersulfone as the functional group of the ultrafiltration membrane with polyethyleneimine. Experimental elucidation of the reaction between the PEI amine and carboxyl groups is challenging, and an MD simulation was thus employed. Furthermore, the simulation results show that the PEI and carboxylated polyethersulfone polymers react with each other in a temperature‐dependent manner. While no reaction occurs at 298 K, carboxylated polyethersulfone and PEI begin to react when the temperature is increased from 298 to 323 K. Furthermore, a reversible reaction was observed with a subsequent increase in temperature to 353 K.
Connectivity and flow regime direct conservation priorities for pelagophil fishes
Authors: Mollenhauer Robert , Brewer Shannon K. , Perkin Joshuah S. , Swedberg Dusty , Wedgeworth Maeghen , Steffensmeier Zachary D. 
Published: June 2021

Abstract

Dam construction threatens global aquatic biodiversity by fragmenting stream networks and altering flow regimes. The negative effects of dams are exacerbated by increased drought periods and associated water withdrawals, especially in semi‐arid regions. Stream fishes are particularly threatened owing to their mobile nature and requirement for multiple habitats to complete their life cycles. An understanding of relationships with fragmentation and flow regimes, particularly as coarse‐scale (e.g. catchment) constraints on species distributions, is essential for stream fish conservation strategies.
Prairie chub (Macrhybopsis australis) is a small‐bodied minnow (Cyprinidae) with poorly understood ecology endemic to the North American Great Plains. Suspected declines in abundance and extirpations have resulted in conservation interest for prairie chub at state and federal levels. Prairie chub is thought to share its reproductive strategy with pelagic‐broadcast spawning minnows (pelagophils). Freshwater pelagic‐broadcast spawning fishes have been disproportionately affected by fragmentation and streamflow alteration globally.
Relationships of prairie chub occurrence with coarse‐scale fragmentation and streamflow metrics were examined in the upper Red River catchment. Occurrence probability was modelled using existing survey data, while accounting for variable detection. The modelled relationships were used to project the distribution of prairie chub in both a wet and dry climatic period.
The probability of prairie chub occurrence was essentially zero at sites with higher densities of upstream dams, but increased sharply with increases in flow magnitude, downstream open mainstem, and flood duration. The projected distribution of prairie chub was broader than indicated by naïve occurrence, but similar in both climatic periods. The occurrence relationships are consistent with the hypotheses of pelagic broadcast spawning and represent coarse‐scale constraints that are useful for identifying areas of the stream network with higher potential for finer‐scale prairie chub conservation and recovery efforts. In addition to informing pelagophil conservation, the relationships are also applicable to pelagic‐broadcast spawning fishes in marine environments.
Nonviral siRNA delivery systems for pancreatic cancer therapy
Authors: Aghamiri Shahin , Raee Pourya , Talaei Sam , Mohammadi‐Yeganeh Samira , Bayat Shiva , Rezaee Delsuz , Ghavidel Afshin A. , Teymouri Alireza , Roshanzamiri Soheil , Farhadi Shohreh , Ghanbarian Hossein 
Published: June 2021

AbstractThe serious drawbacks of the conventional treatment of pancreatic ductal adenocarcinoma (PDAC) such as nonspecific toxicity and high resistance to chemo and radiation therapy, have prompted the development and application of countless small interfering RNA (siRNA)‐based therapeutics. Recent advances in drug delivery systems hold great promise for improving siRNA‐based therapeutics and developing a new class of drugs, known as nano‐siRNA drugs. However, many fundamental questions, regarding toxicity, immunostimulation, and poor knowledge of nano‐bio interactions, need to be addressed before clinical translation. In this review, we provide recent achievements in the design and development of various nonviral delivery vehicles for pancreatic cancer therapy. More importantly, codelivery of conventional anticancer drugs with siRNA as a new revolutionary pancreatic cancer combinational therapy is completely discussed.
Technology transfer of a monitoring system to predict product concentration and purity of biopharmaceuticals in real‐time during chromatographic separation
Authors: Christler Anna , Scharl Theresa , Sauer Dominik G. , Köppl Johannes , Tscheließnig Anne , Toy Cabir , Melcher Michael , Jungbauer Alois , Dürauer Astrid 
Published: June 2021

AbstractTechnological developments require the transfer to their location of application to make use of them. We describe the transfer of a real‐time monitoring system for lab‐scale preparative chromatography to two new sites where it will be used and developed further. Equivalent equipment was used. The capture of a biopharmaceutical model protein, human fibroblast growth factor 2 (FGF‐2) was used to evaluate the system transfer. Predictive models for five quality attributes based on partial least squares regression were transferred. Six out of seven online sensors (UV/VIS, pH, conductivity, IR, RI, and MALS) showed comparable signals between the sites while one sensor (fluorescence) showed different signal profiles. A direct transfer of the models for real‐time monitoring was not possible, mainly due to differences in sensor signals. Adaptation of the models was necessary. Then, among five prediction models, the prediction errors of the test run at the new sites were on average twice as high as at the training site (model‐wise 0.9–5.7 times). Additionally, new prediction models for different products were trained at each new site. These allowed monitoring the critical quality attributes of two new biopharmaceutical products during their purification processes with mean relative deviations between 1% and 33%.