bluuebunny/crossref_metadata_2025_split huggingface dataset:
Red/NIR Thermally Activated Delayed Fluorescence from Aza‐BODIPYs
Authors: Avellanal‐Zaballa Edurne , Prieto‐Castañeda Alejandro , García‐Garrido Fernando , Agarrabeitia Antonia R. , Rebollar Esther , Bañuelos Jorge , García‐Moreno Inmaculada , Ortiz María J. 
Published: July 2020

AbstractThe search for long‐lived red and NIR fluorescent dyes is challenging and hitherto scarcely reported. Herein, the viability of aza‐BODIPY skeleton as a promising system for achieving thermal activated delayed fluorescent (TADF) probes emitting in this target region is demonstrated for the first time. The synthetic versatility of this scaffold allows the design of energy and charge transfer cassettes modulating the stereoelectronic properties of the energy donors, the spacer moieties and the linkage positions. Delayed emission from these architectures is recorded in the red spectral region (695–735 nm) with lifetimes longer than 100 μs in aerated solutions at room temperature. The computational‐aided photophysical study under mild and hard irradiation regimes disclose the interplay between molecular structure and photonic performance to develop long‐lived fluorescence red emitters through thermally activated reverse intersystem crossing. The efficient and long‐lasting NIR emission of the newly synthesized aza‐BODIPY systems provides a basis to develop advanced optical materials with exciting and appealing photonic response.
Tuning the Oxidation States of Dopants: A Strategy for the Modulation of Material Photoluminescence Properties
Authors: Glais Estelle , Massuyeau Florian , Gautier Romain 
Published: July 2020

AbstractDoped single‐phase materials have been widely investigated owing to their easy to implement synthesis and the variety of their properties. This Minireview covers strategies for the co‐stabilization and the ratio control of several oxidation states of dopants inserted in the same host. The tuning of the oxidation states of dopants opens up many possibilities for the optimization of specific properties and can be envisioned for various applications such as telecommunication, medicine, displays, lasers or lighting. Technics used for the quantification of each valence state of dopant are also emphasized, and the importance of high throughput methods for the discovery of efficient materials with dopants in multiple valence states is discussed.
Metal‐only Lewis Pairs of Rhodium with s, p and d‐Block Metals
Authors: Bajo Sonia , Alférez Macarena G. , Alcaide María M. , López‐Serrano Joaquín , Campos Jesús 
Published: July 2020

AbstractMetal‐only Lewis pairs (MOLPs) in which the two metal fragments are solely connected by a dative M→M bond represent privileged architectures to acquire fundamental understanding of bimetallic bonding. This has important implications in many catalytic processes or supramolecular systems that rely on synergistic effects between two metals. However, a systematic experimental/computational approach on a well‐defined class of compounds is lacking. Here we report a family of MOLPs constructed around the RhI precursor [(η5‐C5Me5)Rh(PMe3)2] (1) with a series of s, p and d‐block metals, mostly from the main group elements, and investigate their bonding by computational means. Among the new MOLPs, we have structurally characterized those formed by dative bonding between 1 and MgMeBr, AlMe3, GeCl2, SnCl2, ZnMe2 and Zn(C6F5)2, as well as spectroscopically identified the ones resulting from coordination to MBArF (M=Na, Li; BArF−=[B(C6H2‐3,5‐(CF3)2)4]−) and CuCl. Some of these compounds represent unique examples of bimetallic structures, such as the first unambiguous cases of Rh→Mg dative bonding or base‐free rhodium bound germylene and stannylene species. Multinuclear NMR spectroscopy, including 103Rh NMR, is used to probe the formation of Rh→M bonds. A comprehensive theoretical analysis of those provides clear trends. As anticipated, greater bond covalency is found for the more electronegative acids, whereas ionic character dominates for the least electronegative nuclei, though some degree of electron sharing is identified in all cases.
An Imidazolium‐Based Lipid Analogue as a Gene Transfer Agent
Authors: Paulisch Tiffany O. , Bornemann Steffen , Herzog Marius , Kudruk Sergej , Roling Lena , Linard Matos Anna Livia , Galla Hans‐Joachim , Gerke Volker , Winter Roland , Glorius Frank 
Published: July 2020

AbstractA dicationic imidazolium salt is described and investigated towards its application for gene transfer. The polar head group and the long alkyl chains in the backbone contribute to a lipid‐like behavior, while an alkyl ammonium group provides the ability for crucial electrostatic interaction for the transfection process. Detailed biophysical studies regarding its impact on biological membrane models and the propensity of vesicle fusion are presented. Fluorescence spectroscopy, atomic force microscopy and confocal fluorescence microscopy show that the imidazolium salt leads to negligible changes in lipid packing, while displaying distinct vesicle fusion properties. Cell culture experiments reveal that mixed liposomes containing the novel imidazolium salt can serve as plasmid DNA delivery vehicles. In contrast, a structurally similar imidazolium salt without a second positive charge showed no ability to support DNA transfection into cultured cells. Thus, we introduce a novel and variable structural motif for cationic lipids, expanding the field of lipofection agents.
A sequential split‐and‐conquer approach for the analysis of big dependent data in computer experiments
Authors: Li Chengrui , Hung Ying , Xie Minge 
Published: July 2020

AbstractMassive correlated data with many inputs are often generated from computer experiments to study complex systems. The Gaussian process (GP) model is a widely used tool for the analysis of computer experiments. Although GPs provide a simple and effective approximation to computer experiments, two critical issues remain unresolved. One is the computational issue in GP estimation and prediction where intensive manipulations of a large correlation matrix are required. For a large sample size and with a large number of variables, this task is often unstable or infeasible. The other issue is how to improve the naive plug‐in predictive distribution which is known to underestimate the uncertainty. In this article, we introduce a unified framework that can tackle both issues simultaneously. It consists of a sequential split‐and‐conquer procedure, an information combining technique using confidence distributions (CD), and a frequentist predictive distribution based on the combined CD. It is shown that the proposed method maintains the same asymptotic efficiency as the conventional likelihood inference under mild conditions, but dramatically reduces the computation in both estimation and prediction. The predictive distribution contains comprehensive information for inference and provides a better quantification of predictive uncertainty as compared with the plug‐in approach. Simulations are conducted to compare the estimation and prediction accuracy with some existing methods, and the computational advantage of the proposed method is also illustrated. The proposed method is demonstrated by a real data example based on tens of thousands of computer experiments generated from a computational fluid dynamic simulator.
Happy Photometry–Tips and Tricks against the Pitfalls when using a School Photometer
Authors: Ehli Christian 
Published: July 2020

AbstractMit Hilfe von Fotometrie lässt sich auch in der Schule eine Vielzahl an naturwissenschaftlichen Projekten durchführen. Hierbei ist es empfehlenswert, eine Reihe experimenteller Parameter zu beachten. Der folgende Artikel ist eine Hilfestellung, um mögliche Störeffekte zu identifizieren und ggf. zu entfernen.
Evolution of the speech‐ready brain: The voice/jaw connection in the human motor cortex
Authors: Brown Steven , Yuan Ye , Belyk Michel 
Published: July 2020

AbstractA prominent model of the origins of speech, known as the “frame/content” theory, posits that oscillatory lowering and raising of the jaw provided an evolutionary scaffold for the development of syllable structure in speech. Because such oscillations are nonvocal in most nonhuman primates, the evolution of speech required the addition of vocalization onto this scaffold in order to turn such jaw oscillations into vocalized syllables. In the present functional MRI study, we demonstrate overlapping somatotopic representations between the larynx and the jaw muscles in the human primary motor cortex. This proximity between the larynx and jaw in the brain might support the coupling between vocalization and jaw oscillations to generate syllable structure. This model suggests that humans inherited voluntary control of jaw oscillations from ancestral species, but added voluntary control of vocalization onto this via the evolution of a new brain area that came to be situated near the jaw region in the human motor cortex.
Functionalized Nanogap for DNA Read‐Out: Nucleotide Rotation and Current‐Voltage Curves
Authors: Maier Frank C. , Fyta Maria 
Published: July 2020

AbstractFunctionalized nanogaps embedded in nanopores show a strong potential for enhancing the detection of biomolecules, their length, type, and sequence. This detection is strongly dependent on the features of the target biomolecules, as well as the characteristics of the sensing device. In this work, through quantum‐mechanical calculations, we elaborate on representative such aspects for the specific case of DNA detection and read‐out. These aspects include the influence of single DNA nucleotide rotation within the nanogap and the current‐voltage (I‐V) characteristics of the nanogap. The results unveil a distinct variation in the electronic current across the functionalized device for the four natural DNA nucleotides with the applied voltage. These also underline the asymmetric response of the rotating nucleotides on this applied voltage and the respective variation in the rectification ratio of the device. The electronic tunneling current across the nanogap can be further enhanced through the proper choice of an applied bias voltage. We were able to correlate the enhancement of this current to the nucleotide rotation dynamics and a shift of the electronic transmission peaks towards the Fermi level. This nucleotide specific shift further reveals the sensitivity of the device in reading‐out the identity of the DNA nucleotides for all different configurations in the nanogap. We underline the important information that can be obtained from both the I‐V curves and the rectification characteristics of the nanogap device in view of accurately reading‐out the DNA information. We show that tuning the applied bias can enhance this detection and discuss the implications in view of novel functionalized nanopore sequencers.
Molecular Modification of Single Cobalt Sites Boosts the Catalytic Activity of CO2 Electroreduction into CO
Authors: Zhong Yongzhi , Kong Xiangdong , Geng Zhigang , Zeng Jie , Luo Xuan , Zhang Lin 
Published: July 2020

AbstractElectroreduction of CO2 into carbonaceous fuels or industrial chemicals using renewable energy sources is an ideal way to promote global carbon recycling. Thus, it is of great importance to develop highly selective, efficient, and stable catalysts. Herein, we prepared cobalt single atoms (Co SAs) coordinated with phthalocyanine (Co SAs‐Pc). The anchoring of phthalocyanine with Co sites enabled electron transfer from Co sites to CO2 effectively via the π‐conjugated system, resulting in high catalytic performance of CO2 electroreduction into CO. During the process of CO2 electroreduction, the Faradaic efficiency (FE) of Co SAs‐Pc for CO was as high as 94.8 %. Meanwhile, the partial current density of Co SAs‐Pc for CO was −11.3 mA cm−2 at −0.8 V versus the reversible hydrogen electrode (vs RHE), 18.83 and 2.86 times greater than those of Co SAs (−0.60 mA cm−2) and commercial Co phthalocyanine (−3.95 mA cm−2), respectively. In an H‐cell system operating at −0.8 V vs RHE over 10 h, the current density and FE for CO of Co SAs‐Pc dropped by 3.2 % and 2.5 %. A mechanistic study revealed that the promoted catalytic performance of Co SAs‐Pc could be attributed to the accelerated reaction kinetics and facilitated CO2 activation.
High‐Throughput Approaches for the Discovery of Supramolecular Organic Cages
Authors: Greenaway Rebecca L. , Jelfs Kim E. 
Published: July 2020

AbstractThe assembly of complex molecules, such as organic cages, can be achieved through supramolecular and dynamic covalent strategies. Their use in a range of applications has been demonstrated, including gas uptake, molecular separations, and in catalysis. However, the targeted design and synthesis of new species for particular applications is challenging, particularly as the systems become more complex. High‐throughput computation‐only and experiment‐only approaches have been developed to streamline the discovery process, although are still not widely implemented. Additionally, combined hybrid workflows can dramatically accelerate the discovery process and lead to the serendipitous discovery and rationalisation of new supramolecular assemblies that would not have been designed based on intuition alone. This Minireview focuses on the advances in high‐throughput approaches that have been developed and applied in the discovery of supramolecular organic cages.
Recent Advances in Heterogeneous Photo‐Driven Oxidation of Organic Molecules by Reactive Oxygen Species
Authors: Luo Lan , Zhang Tingting , Wang Miao , Yun Rongping , Xiang Xu 
Published: July 2020

AbstractThe photo‐driven oxidation of organic molecules into corresponding high‐value‐added products has become a promising method in chemical synthesis. This strategy can drive thermodynamically non‐spontaneous reactions and achieve challenging thermocatalytic processes under ambient conditions. Reactive oxygen species (ROS) are not only significant intermediates for producing target products via photoinduced oxidation reactions but also contribute to the creation of sustainable chemical processes. Here, the latest advances in heterogeneous photo‐driven oxidation reactions involving ROS are summarized. The major types of ROS and their generation are introduced, and the behaviors of various ROS involved in photo‐driven processes are reviewed in terms of the formation of different bonds. Emphasis is placed on unraveling the reaction mechanisms of ROS and establishing strategies for their regulation, and the remaining challenges and perspectives are summarized and analyzed. This Review is expected to provide an in‐depth understanding of the mechanisms of ROS involved in photo‐driven oxidation processes as an important foundation for the design of efficient catalysts. Clarifying the role of ROS in oxidation reactions has important scientific significance for improving the atomic and energy efficiency of reactions in practical applications.
N‐Butylpyrrolidinone for Solid‐Phase Peptide Synthesis is Environmentally Friendlier and Synthetically Better than DMF
Authors: Kumar Ashish , Alhassan Mahama , Lopez John , Albericio Fernando , de la Torre Beatriz G. 
Published: July 2020

AbstractSolid‐phase peptide synthesis (SPPS) is the method of choice for the preparation of peptides in both laboratory scale and large production. Although the methodology has been improved during the last decades allowing the achievement of long peptides and challenging sequences in good yields and purities, the process was not revised from an environmental point of view. One of the main problems in this regard is the large amount of solvents used, and therefore the tons of generated waste. Moreover, the solvent of choice for the SPPS is N,N‐dimethylformamide (DMF), which is considered as reprotoxic; thus, there is an urgent necessity to replace it with safer solvents. The DMF substitution by a green solvent is not a trivial task, because it should solubilize all the reagents and byproducts involved in the process, and, in addition to facilitating the coupling of the different amino acids, it should not favor the formation of side‐reactions compared with DMF. Herein, it was demonstrated that the use of the green solvent N‐butylpyrrolidinone (NBP) as a replacement of DMF was beneficial in two well‐documented side reactions in peptide synthesis, racemization and aspartimide formation. The use of NBP rendered a lower or equal level of racemization in the amino acids more prone to this side reaction than DMF, whilst the aspartimide formation was clearly lower when NBP was used as solvent. Our findings demonstrate that the use of a green solvent does not hamper the synthetic process and could even improve it, making it environmentally friendlier and synthetically better.
Enhancing quality of experience using peer‐to‐peer overlay on device‐to‐device communications
Authors: Tetarave Sumit , Tripathy Somanath , Ghosh Ratan 
Published: July 2020

SummaryWith the recent development of LTE‐A/5G technologies, data sharing among mobile devices offer an attractive opportunity to reduce Internet access. However, it requires smart strategies to share the data with low trade‐offs in time, cost, and energy. Several existing schemes offer a super‐peer‐based two‐tier model using a distributed hash table (DHT) organization for smart devices having device‐to‐device (D2D)/Bluetooth/WiFi capabilities. The primary focus of these schemes has been to reduce Internet usage by increased D2D content sharing. However, the real challenge is not in creating a two‐tier model, but evolving an efficient overlay that offers enhanced opportunities for D2D content sharing over the existing model. In this paper, we formulated a P‐median‐based selection of tier‐1 devices in a distribution network and solved it using the Lagrangian relaxation method. The tier‐2 devices become clients seeking content sharing services from tier‐1 devices. A strong motivation in this work is to raise a user's perception of the grade of service known as quality of experience (QoE). We analyzed the challenge for QoE assessment in resource‐constrained smartphones under the proposed model of enhanced D2D communication. Our focus is to establish a framework to evaluate QoE for applications and services over LTE‐A/5G networks with an improved D2D communication level. The simulation and the experimental results validate the claim that substantial improvements in QoE are possible with the proposed mathematical model for selecting and placing tier‐1 mobile devices and maintaining a DHT for D2D communication.
EXFI: Exon and splice graph prediction without a reference genome
Authors: Langa Jorge , Estonba Andone , Conklin Darrell 
Published: July 2020

AbstractFor population genetic studies in nonmodel organisms, it is important to use every single source of genomic information. This paper presents EXFI, a Python pipeline that predicts the splice graph and exon sequences using an assembled transcriptome and raw whole‐genome sequencing reads. The main algorithm uses Bloom filters to remove reads that are not part of the transcriptome, to predict the intron–exon boundaries, to then proceed to call exons from the assembly, and to generate the underlying splice graph. The results are returned in GFA1 format, which encodes both the predicted exon sequences and how they are connected to form transcripts. EXFI is written in Python, tested on Linux platforms, and the source code is available under the MIT License at https://github.com/jlanga/exfi.
Potassium Concentration Alters Calibration Sensitivities of Dopamine but not Serotonin
Authors: Herrmann Mareike , Abdalla Aya , Patel Bhavik Anil 
Published: July 2020

AbstractThe use of carbon fibre microelectrodes and amperometric techniques for measurement of biological molecules has been widely studied. The use of calibrations to translate biological data is common practice between labs. Tris buffer is commonly used for conducting calibrations, where potassium ion concentrations are varied in buffers. However, little is known about how changes in this ion alter the calibration sensitivity of neurotransmitters. This work showcases that dopamine calibrations are highly dependent on the concentration of potassium ions, whilst serotonin is less affected. Our findings have implications on interpretation and comparison of measurements between different studies.
Electro‐oxidation of Ethanol and Methanol on Pd/C, Pd/CNFs and Pd−Ru/CNFs Nanocatalysts in Alkaline Direct Alcohol Fuel Cell
Authors: Sikeyi Ludwe L. , Matthews Thabo , Adekunle Abolanle S. , Maxakato Nobanathi W. 
Published: July 2020

AbstractPd/C, Pd/CNFs and Pd−Ru/CNFs nanocomposite materials were utilized as anode nanocatalysts in low‐temperature alkaline direct alcohol fuel cells. The palladium based nanocatalysts performance and stability were firmly relying upon the attributes of the carbon nanofibers (CNFs). CNFs were successfully synthesized employing a chemical vapour deposition method. The nanocatalysts were synthesized by dispersing Pd and Pd−Ru nanoparticles onto the CNFs surface using alcohol reduction method. The physical properties of the synthesized nanocatalysts were explored utilizing several techniques such as transmission electron microscope (TEM), scanning electron microscope‐Energy dispersive x‐ray (SEM‐EDX), X‐ray diffraction spectroscopy (XRD), X‐ray photoelectron spectroscopy (XPS) and Inductively Coupled Plasma Optical Emission Spectrometry (ICP‐OES) and confirmed successful synthesis of Pd/C, Pd/CNFs and Pd−Ru/CNFs nanocomposite. TEM showed that Pd and Ru nanoparticles were uniformly dispersed on the CNFs support surface. ICP‐OES determined the palladium and ruthenium concentration in Pd/C, Pd/CNFs and Pd−Ru/CNFs nanocatalysts to be Pd (7.67 %), Pd (7.74 %), Pd (7.82 %) and Ru (3.22 %) respectively. The three prepared nanocatalysts were evaluated by cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) in the evaluation of ethanol and methanol oxidation reactions. CV, CA and EIS experiments of Pd−Ru/CNFs nanocatalyst displayed superior activity towards alcohol oxidation reaction in alkaline conditions than Pd/CNFs and commercial Pd/C nanocatalysts.
Structure and conductivity of AOT solutions in n‐hexadecane‐chloroform mixtures
Authors: Shaparenko Nikita O. , Kompan'kov Nikolay B. , Demidova Marina G. , Bulavchenko Alexander I. 
Published: July 2020

AbstractThe structure and conductivity of AOT (sodium bis(2‐ethylhexyl) sulfosuccinate) solutions (2.5 × 10−4–2.5 × 10−1 M) in n‐hexadecane‐chloroform mixture at the chloroform concentration from 50 to 100 vol% were studied. The diffusion ordered spectroscopy NMR study revealed that in the indicated range, the observed hydrodynamic diameter of micelles depends only on the AOT concentration and does not depend on the chloroform content. Molar fractions of free AOT molecules and those aggregated into micelles were calculated using the Lindman's law: at concentrations above 2.5 × 10−1 М, the solutions contain mostly the micelles, whereas at concentrations below 2.5 × 10−4 M, the solutions contain AOT molecules. The transition region contains both the AOT molecules and the micelles. Conductivity measurements were used to determine free charge carriers in the bulk of solutions and their contributions to conductivity.