bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessing inbred–hybrid relationships for developing drought‐tolerant provitamin A–quality protein maize hybrids
Authors: Obeng‐Bio Ebenezer , Badu‐Apraku Baffour , Ifie Beatrice Elohor , Danquah Agyemang , Blay Essie T. , Dadzie Mustapha Abu 
Published: June 2020

AbstractDrought‐tolerant early‐maturing maize (Zea mays L.) inbred lines with high levels of provitamin A (PVA) and quality protein (QPM) are urgently needed for development of superior hybrids to mitigate malnutrition and to intensify maize production and productivity in sub‐Saharan Africa (SSA). This study was designed to identify early‐maturing inbred lines with combined tolerance to drought, elevated tryptophan, and PVA contents; to examine inbred–hybrid relationships for tryptophan and PVA accumulation; and to select hybrids with outstanding grain yield (GY) performance. A total of 64 inbred lines and six checks, plus 96 hybrids and four checks, were evaluated under drought and well‐watered environments in Nigeria for 2 yr. Eighteen parental lines and 54 derived hybrids were assayed for tryptophan and PVA contents. Ten drought‐tolerant inbred lines with high tryptophan and elevated PVA levels were identified in the top 10 hybrid combinations across managed drought and well‐watered conditions. The inbred–hybrid relationship was significant for GY under each and across the two contrasting environments. Significant average heterosis was found for tryptophan and PVA under well‐watered conditions. This indicated that the selected inbred lines could be used for developing high‐yielding PVA‐QPM hybrids tolerant to drought stress in SSA. The 10 top‐performing PVA‐QPM hybrids identified are being extensively evaluated in different locations and subsequently in on‐farm trials for commercialization throughout SSA.
A Self‐Consistent Model for Sorption and Transport in Polyimide‐Derived Carbon Molecular Sieve Gas Separation Membranes
Authors: Sanyal Oishi , Hays Samuel S. , León Nicholas E. , Guta Yoseph A. , Itta Arun K. , Lively Ryan P. , Koros William J. 
Published: June 2020

AbstractDemand for energy‐efficient gas separations exists across many industrial processes, and membranes can aid in meeting this demand. Carbon molecular sieve (CMS) membranes show exceptional separation performance and scalable processing attributes attractive for important, similar‐sized gas pairs. Herein, we outline a mathematical and physical framework to understand these attributes. This framework shares features with dual‐mode transport theory for glassy polymers; however, physical connections to CMS model parameters differ from glassy polymer cases. We present evidence in CMS membranes for a large volume fraction of microporous domains characterized by Langmuir sorption in local equilibrium with a minority continuous phase described by Henry's law sorption. Using this framework, expressions are provided to relate measurable parameters for sorption and transport in CMS materials. We also outline a mechanism for formation of these environments and suggest future model refinements.
Rational Design of Microporous MOFs with Anionic Boron Cluster Functionality and Cooperative Dihydrogen Binding Sites for Highly Selective Capture of Acetylene
Authors: Zhang Yuanbin , Hu Jianbo , Krishna Rajamani , Wang Lingyao , Yang Lifeng , Cui Xili , Duttwyler Simon , Xing Huabin 
Published: June 2020

AbstractSeparation of acetylene (C2H2) from carbon dioxide (CO2) or ethylene (C2H4) is important in industry but limited by the low capacity and selectivity owing to their similar molecular sizes and physical properties. Herein, we report two novel dodecaborate‐hybrid metal–organic frameworks, MB12H12(dpb)2 (termed as BSF‐3 and BSF‐3‐Co for M=Cu and Co), for highly selective capture of C2H2. The high C2H2 capacity and remarkable C2H2/CO2 selectivity resulted from the unique anionic boron cluster functionality as well as the suitable pore size with cooperative proton‐hydride dihydrogen bonding sites (B−Hδ−⋅⋅⋅Hδ+−C≡C−Hδ+⋅⋅⋅Hδ−−B). This new type of C2H2‐specific functional sites represents a fresh paradigm distinct from those in previous leading materials based on open metal sites, strong electrostatics, or hydrogen bonding.
Insect‐Associated Bacteria Assemble the Antifungal Butenolide Gladiofungin by Non‐Canonical Polyketide Chain Termination
Authors: Niehs Sarah P. , Kumpfmüller Jana , Dose Benjamin , Little Rory F. , Ishida Keishi , Flórez Laura V. , Kaltenpoth Martin , Hertweck Christian 
Published: June 2020

AbstractGenome mining of one of the protective symbionts (Burkholderia gladioli) of the invasive beetle Lagria villosa revealed a cryptic gene cluster that codes for the biosynthesis of a novel antifungal polyketide with a glutarimide pharmacophore. Targeted gene inactivation, metabolic profiling, and bioassays led to the discovery of the gladiofungins as previously‐overlooked components of the antimicrobial armory of the beetle symbiont, which are highly active against the entomopathogenic fungus Purpureocillium lilacinum. By mutational analyses, isotope labeling, and computational analyses of the modular polyketide synthase, we found that the rare butenolide moiety of gladiofungins derives from an unprecedented polyketide chain termination reaction involving a glycerol‐derived C3 building block. The key role of an A‐factor synthase (AfsA)‐like offloading domain was corroborated by CRISPR‐Cas‐mediated gene editing, which facilitated precise excision within a PKS domain.
Diradical Organic One‐Dimensional Polymers Synthesized on a Metallic Surface
Authors: Sánchez‐Grande Ana , Urgel José I. , Cahlík Aleš , Santos José , Edalatmanesh Shayan , Rodríguez‐Sánchez Eider , Lauwaet Koen , Mutombo Pingo , Nachtigallová Dana , Nieman Reed , Lischka Hans , de la Torre Bruno , Miranda Rodolfo , Gröning Oliver , Martín Nazario , Jelínek Pavel , Écija David 
Published: June 2020

AbstractWe report on the synthesis and characterization of atomically precise one‐dimensional diradical peripentacene polymers on a Au(111) surface. By means of high‐resolution scanning probe microscopy complemented by theoretical simulations, we provide evidence of their magnetic properties, which arise from the presence of two unpaired spins at their termini. Additionally, we probe a transition of their magnetic properties related to the length of the polymer. Peripentacene dimers exhibit an antiferromagnetic (S=0) singlet ground state. They are characterized by singlet–triplet spin‐flip inelastic excitations with an effective exchange coupling (Jeff) of 2.5 meV, whereas trimers and longer peripentacene polymers reveal a paramagnetic nature and feature Kondo fingerprints at each terminus due to the unpaired spin. Our work provides access to the precise fabrication of polymers featuring diradical character which are potentially useful in carbon‐based optoelectronics and spintronics.
Structural Elucidation of the Mechanism of Molecular Recognition in Chiral Crystalline Sponges
Authors: Zhang Shi‐Yuan , Fairen‐Jimenez David , Zaworotko Michael J. 
Published: June 2020

AbstractTo gain insight into chiral recognition in porous materials we have prepared a family of fourth generation chiral metal–organic frameworks (MOFs) that have rigid frameworks and adaptable (flexible) pores. The previously reported parent material, [Co2(S‐mandelate)2(4,4′‐bipyridine)3](NO3)2, CMOM‐1S, is a modular MOF; five new variants in which counterions (BF4−, CMOM‐2S) or mandelate ligands are substituted (2‐Cl, CMOM‐11R; 3‐Cl, CMOM‐21R; 4‐Cl, CMOM‐31R; 4‐CH3, CMOM‐41R) and the existing CF3SO3−variant CMOM‐3Sare studied herein. Fine‐tuning of pore size, shape, and chemistry afforded a series of distinct host–guest binding sites with variable chiral separation properties with respect to three structural isomers of phenylpropanol. Structural analysis of the resulting crystalline sponge phases revealed that host–guest interactions, guest–guest interactions, and pore adaptability collectively determine chiral discrimination.
Design of Optical‐Imaging Probes by Screening of Diverse Substrate Libraries Directly in Disease‐Tissue Extracts
Authors: Tholen Martina , Yim Joshua J. , Groborz Katarzyna , Yoo Euna , Martin Brock A. , van den Berg Nynke S. , Drag Marcin , Bogyo Matthew 
Published: June 2020

AbstractFluorescently quenched probes that are specifically activated in the cancer microenvironment have great potential application for diagnosis, early detection, and surgical guidance. These probes are often designed to target specific enzymes associated with diseases by direct optimization using single purified enzymes. However, this can result in painstaking chemistry efforts to produce a probe with suboptimal performance when applied in vivo. We describe here an alternate, unbiased activity‐profiling approach in which whole tissue extracts are used to directly identify optimal peptide sequences for probe design. Screening of tumor extracts with a hybrid combinatorial substrate library (HyCoSuL) identified a combination of natural and non‐natural amino‐acid residues that was used to generate highly efficient tumor‐specific probes. This new strategy simplifies and enhances the process of probe optimization without any a priori knowledge of enzyme targets and has the potential to be applied to diverse disease states using clinical or animal‐model tissue samples.
In Situ Dispersion of Palladium on TiO2 During Reverse Water–Gas Shift Reaction: Formation of Atomically Dispersed Palladium
Authors: Nelson Nicholas C. , Chen Linxiao , Meira Debora , Kovarik Libor , Szanyi János 
Published: June 2020

AbstractThe application of single‐atom catalysts (SACs) to high‐temperature hydrogenation requires materials that thermodynamically favor metal atom isolation over cluster formation. We demonstrate that Pd can be predominantly dispersed as isolated atoms onto TiO2 during the reverse water–gas shift (rWGS) reaction at 400 °C. Achieving atomic dispersion requires an artificial increase of the absolute TiO2 surface area by an order of magnitude and can be accomplished by physically mixing a precatalyst (Pd/TiO2) with neat TiO2 prior to the rWGS reaction. The in situ dispersion of Pd was reflected through a continuous increase of rWGS activity over 92 h and supported by kinetic analysis, infrared and X‐ray absorption spectroscopies and scanning transmission electron microscopy. The thermodynamic stability of Pd under high‐temperature rWGS conditions is associated with Pd‐Ti coordination, which manifests upon O‐vacancy formation, and the artificial increase in TiO2 surface area.
Comparative study on the properties of cross‐linked cellulose nanocrystals/chitosan film composites with conventional heating and microwave curing
Authors: Gan Pei Gie , Sam Sung Ting , Abdullah Muhammad Faiq , Omar Mohd Firdaus , Tan Wai Kian 
Published: June 2020

AbstractCross‐linking of chitosan film composites was carried out by using conventional heating and microwave curing methods in this study. Non‐cross‐linked and glutaraldehyde (GA) cross‐linked neat chitosan and cellulose nanocrystals (CNC)/chitosan film composites were cured by either conventional oven heating or microwave irradiation. Tensile strength and Young's modulus of chitosan composites were enhanced significantly by the addition of CNC and GA especially for the microwave‐cured samples. The changes in chemical interaction of the chitosan film composites was determined by Fourier transform infrared (FTIR) spectroscopy. The microwave‐cured GA‐cross‐linked chitosan film composites were more thermally stable than non‐cross‐linked and conventionally heated GA‐cross‐linked chitosan film composites due to the formation of a more stable structure between GA and chitosan. Nevertheless, the reduced antimicrobial efficacy of film composites against Escherichia coli, Bacillus subtilis, and Saccharomyces cerevisiae was observed in cross‐linked film composites compared with non‐cross‐linked composites.
The Lifebox Surgical Headlight Project: engineering, testing, and field assessment in a resource-constrained setting
Authors: Starr N , Panda N , Johansen E W , Forrester J A , Wayessa E , Rebollo D , August A , Fernandez K , Bitew S , Mammo T Negussie , Weiser T G 
Published: June 2020

Abstract

Background
Poor surgical lighting represents a major patient safety issue in low-income countries. This study evaluated device performance and undertook field assessment of high-quality headlights in Ethiopia to identify critical attributes that might improve safety and encourage local use.

Methods
Following an open call for submissions (December 2018 to January 2019), medical and technical (non-medical) headlights were identified for controlled specification testing on 14 prespecified parameters related to light quality/intensity, mounting and battery performance, including standardized illuminance measurements over time. The five highest-performing devices (differential illumination, colour rendering, spot size, mounting and battery duration) were distributed to eight Ethiopian surgeons working in resource-constrained facilities. Surgeons evaluated the devices in operating rooms, and in a comparative session rated each headlight in terms of performance and willingness to purchase.

Results
Of 25 submissions, eight headlights (6 surgical and 2 technical) met the criteria for full specification testing. Scores ranged from 8 to 12 (of 14), with differential performance in lighting, mounting and battery domains. Only two headlights met the illuminance parameters of more than 35 000 lux during initial testing, and no headlight satisfied all minimum specifications. Of the five headlights evaluated in Ethiopia, daily operation logbooks noted variability in surgeons' opinions of lighting quality (6–92 per cent) and spot size (0–92 per cent). Qualitative interviews also yielded important feedback, including preference for easy transport. Surgeons sought high quality with price sensitivity (using out-of-pocket funds) and identified the least expensive but high-functioning device as their first choice.

Conclusion
No device satisfied all the predetermined specifications, and large price discrepancies were critical factors leading surgeons' choices. The favoured device is undergoing modification by the manufacturer based on design feedback so an affordable, high-quality surgical headlight crafted specifically for the needs of resource-constrained settings can be used to improve surgical safety.
Transitioning undergraduate research from wet lab to the virtual in the wake of a pandemic
Authors: Chandrasekaran Arun Richard 
Published: June 2020

AbstractThe COVID‐19 outbreak has shut down universities, and teaching faculty have moved to online classrooms to address students. This change has been supported by numerous online teaching tools and development of virtual classrooms. Undergraduate research programs in the sciences and biochemistry/molecular biology teaching labs, however, are affected by this change due to inaccessibility to laboratories. This communication outlines three concepts to engage undergraduate students who are involved in research: (a) remote data analysis, (b) literature review and science writing, and (c) science journal clubs.
Are women eco‐friendly? Board gender diversity and environmental innovation
Authors: Nadeem Muhammad , Bahadar Stephen , Gull Ammar Ali , Iqbal Umer 
Published: June 2020

AbstractAs a result of recent climate change impacts, environmental sustainability has received enormous attention from scholars and policy makers. Environmental innovation is one of the major ways of acting in harmony with the environment, but it also requires a significant amount of resources and strong corporate commitment. As boards of directors have great influence over the strategic direction of firms and are responsible for corporate environmentalism, we examine the likely relationship between board gender diversity (BGD) and environmental innovation measured as process innovation and product innovation. Based on a relatively large dataset (10,334 firm‐year observations) of U.S. listed firms, we find that BGD has a significant positive association with environmental innovation. Furthermore, we also find that this relationship is more pronounced in less profitable firms and in environmentally sensitive industries. Our results remain robust to endogeneity issues and alternative proxies. We interpret our results under upper echelon and gender socialization theories and suggest important implications for policy makers.
Transition‐Metal‐Mediated Modification of Biomolecules
Authors: Rodríguez Jessica , Martínez‐Calvo Miguel 
Published: June 2020

AbstractThe site‐selective modification of biomolecules has grown spectacularly in recent years. The presence of a large number of functional groups in a biomolecule makes its chemo‐ and regioselective modification a challenging goal. In this context, transition‐metal‐mediated reactions are emerging as a powerful tool owing to their unique reactivity and good functional group compatibility, allowing highly efficient and selective bioconjugation reactions that operate under mild conditions. This Minireview focuses on the current state of organometallic chemistry for bioconjugation, highlighting the potential of transition metals for the development of chemoselective and site‐specific methods for functionalization of peptides, proteins and nucleic acids. The importance of the selection of ligands attached to the transition metal for conferring the desired chemoselectivity will be highlighted.
A Porous Mooncake‐Shaped Li4Ti5O12 Anode Material Modified by SmF3 and Its Electrochemical Performance in Lithium Ion Batteries
Authors: Wang Bo , Hu Sisi , Gu Lin , Zhang Di , Li Yazhao , Sun Huilan , Li Wen , Wang Qiujun 
Published: June 2020

AbstractReasonably designing and synthesizing advanced electrode materials is significant to enhance the electrochemical performance of lithium ion batteries (LIBs). Herein, a metal–organic framework (MOF, Mil‐125) was used as a precursor and template to successfully synthesize the porous mooncake‐shaped Li4Ti5O12 (LTO) anode material assembled from nanoparticles. Even more critical, SmF3 was used to modify the prepared porous mooncake‐shaped LTO material. The SmF3‐modified LTO maintained a porous mooncake‐shaped structure with a large specific surface area, and the SmF3 nanoparticles were observed to be attach on the surface of the LTO material. It has been proven that the SmF3 modification can further facilitate the transition from Ti4+ to Ti3+, reduce the polarization of electrode, decrease charge transfer impedance (Rct) and solid electrolyte interface impedance (Rsei), and increase the lithium ion diffusion coefficient (DLi), thereby enhancing the electrochemical performance of LTO. Therefore, the porous mooncake‐shaped LTO modified using 2 wt % SmF3 displays a large specific discharge capacity of 143.8 mAh g−1 with an increment of 79.16 % compared to pure LTO at a high rate of 10 C (1 C=170 mAh g−1), and shows a high retention rate of 96.4 % after 500 cycles at 5 C‐rate.
Investigating Ugi/Passerini Multicomponent Reactions for the Site‐Selective Conjugation of Native Trastuzumab**
Authors: Sornay Charlotte , Hessmann Steve , Erb Stéphane , Dovgan Igor , Ehkirch Anthony , Botzanowski Thomas , Cianférani Sarah , Wagner Alain , Chaubet Guilhem 
Published: June 2020

AbstractSite‐selective modification of proteins has been the object of intense studies over the past decades, especially in the therapeutic field. Prominent results have been obtained with recombinant proteins, for which site‐specific conjugation is made possible by the incorporation of particular amino acid residues or peptide sequences. In parallel, methods for the site‐selective and site‐specific conjugation of native and natural proteins are starting to thrive, allowing the controlled functionalization of various types of amino acid residues. Pursuing the efforts in this field, we planned to develop a new type of site‐selective method, aiming at the simultaneous conjugation of two amino acid residues. We reasoned that this should give higher chances of developing a site‐selective strategy compared to the great majority of existing methods that solely target a single residue. We opted for the Ugi four‐centre three‐component reaction to implement this idea, with the aim of conjugating the side‐chain amine and carboxylate groups of two neighbouring lysine and aspartate/glutamate. Herein, we show that this strategy can give access to valuable antibody conjugates bearing several different payloads; furthermore, the approach limits the potential conjugation sites to only six on the model antibody trastuzumab.
Formation of Highly Efficient, Long‐Lived Charge Separated States in Star‐Shaped Ferrocene‐Diketopyrrolopyrrole‐Triphenylamine Donor–Acceptor–Donor Conjugates
Authors: Popli Charu , Jang Youngwoo , Patil Yuvraj , Misra Rajneesh , D'Souza Francis 
Published: June 2020

AbstractThe significance of multiple number of donor–acceptor entities on a central electron donor in a star‐shaped molecular system in improving light energy harvesting ability is reported. For this, donor–acceptor–donor type conjugates comprised up to three entities ferrocenyl (Fc)‐diketopyrrolopyrrole (DPP) onto a central triphenylamine (TPA), (4–6) by the Pd‐catalyzed Sonogashira cross‐coupling reactions have been newly synthesized and characterized. Donor–acceptor conjugates possessing diketopyrrolopyrrole (1 to 3 entities) onto the central triphenylamine, (1–3) served as reference dyads while monomeric DPP and Fc‐DPP served as control compounds. Both DPP and Fc‐DPP carrying conjugates exhibited red‐shifted absorption compared to their respective control compounds revealing existence of ground state interactions. Furthermore, DPP fluorescence in 4–6 was found to be quantitatively quenched while for 1–3, this property varied between 73–65 % suggesting occurrence moderate amounts of excited state events. The electrochemical investigations exhibited an additional low potential oxidation in the case of Fc‐DPP‐TPA based derivatives (4–6) owing to the presence of ferrocene unit(s). This was in addition to DPP and TPA redox peaks. Using spectral, electrochemical and computational studies, Gibbs free‐energy calculations were performed to visualize excited state charge separation (ΔGCS) in these donor–acceptor conjugates as a function of different number of Fc‐DPP entities. Formation of Fc+‐DPP.−‐TPA charge separated states (CSS) in the case of 4–6 was evident. Using spectroelectrochemical studies, spectrum of CSS was deduced. Finally, femtosecond transient absorption spectral studies were performed to gather information on excited state charge separation. Increasing the number of Fc‐DPP entities in 4–6 improved charge separation rates. Surprisingly, lifetime of the charge separated state, Fc+‐DPP.−‐TPA was found to persist longer with an increase in the number of Fc‐DPP entities in 4–6 as compared to Fc‐DPP‐control and simple DPP derived donor–acceptor conjugates in literature. This unprecedented result has been attributed to subtle changes in ΔGCS and ΔGCR and the associated electron coupling between different entities.