bluuebunny/crossref_metadata_2025_split huggingface dataset:
Centimeter‐Sized Molecular Perovskite Crystal for Efficient X‐Ray Detection
Authors: Ma Chuang , Chen Fang , Song Xin , Chen Ming , Gao Lili , Wang Peijun , Wen Jialun , Yang Zhou , Tang Youzhi , Zhao Kui , Liu Shengzhong (Frank) 
Published: March 2021

AbstractMolecular perovskites have demonstrated great potential for ferroelectrics and nonlinear optics; however, their charge transport properties for optoelectronics have rarely been explored. Here, understanding of charge transport behavior of molecular perovskite under X‐ray excitation based on centimeter‐scale TMCM‐CdCl3 (TMCM+, trimethylchloromethyl ammonium) single crystal is demonstrated. The crystal is fabricated from an aqueous solution and exhibits a large bandgap of 5.51 eV, with the valence band maximum mainly dominated by the Cl‐p/Cd‐d states and the conduction band minimum primarily by Cd‐s/Cl‐p states. Charge mobility exceeding 40 cm2 V−1 s−1 and mobility–lifetime (µτ) product on the order of 10−4 cm2 V−1 for the crystal are observed. These excellent optoelectronic properties translate to an efficient photoresponse under X‐ray excitation, with the sensitivity reaching 128.9 ± 4.64 µC Gyair−1 cm−2 [fivefold higher than that of the commercialized amorphous selenium (α‐Se)] and a low detection limit of 1.06 μC Gyair−1 s−1 (10 V bias). This work pioneers a superior metal‐based molecular perovskite single‐crystal based paradigm for optoelectronic investigation, which may lead to the discovery of a new generation of X‐ray detection and imaging materials.
Recombinant Human Epidermal Growth Factor/Quatsome Nanoconjugates: A Robust Topical Delivery System for Complex Wound Healing
Authors: Ferrer‐Tasies Lidia , Santana Hector , Cabrera‐Puig Ingrid , González‐Mira Elisabet , Ballell‐Hosa Lídia , Castellar‐Álvarez Carla , Córdoba Alba , Merlo‐Mas Josep , Gerónimo Haydee , Chinea Glay , Falcón Viviana , Moreno‐Calvo Evelyn , Pedersen Jan Skov , Romero Jessica , Navarro‐Requena Claudia , Valdés Calixto , Limonta Miladys , Berlanga Jorge , Sala Santiago , Martínez Eduardo , Veciana Jaume , Ventosa Nora 
Published: March 2021

AbstractA multitude of microparticles and nanoparticles is developed to improve the delivery of different small drugs and large biomolecules, which are subject to several hindering biological barriers that limit their optimal biodistribution and therapeutic effects. Here, a soft, reliable, and scalable method based on compressed CO2 is reported for obtaining nanoconjugates of recombinant human epidermal growth factor and nanovesicles called quatsomes, where the latter consists of cholesterol and cetyltrimethylammonium bromide. These nanoconjugates exhibit appropriate values of the major critical quality attributes of colloidal nanomedicines, such as controlled and narrow nanoscopic particle size distribution (which play important roles in determining their stability), drug loading, drug release, drug protection, targeting ability, and bioactivity. Also, they exhibit a dual action by 1) inbuilt antimicrobial activity preventing infections and 2) promoting regeneration of granulation tissue and re‐epithelialization with complete closure of complex wounds. Therefore, such nanoconjugates are a potential nanomedicine for the topical treatment of complex wounds, particularly diabetic foot ulcers and venous leg ulcers.
Reduced Graphene Oxide Tattoo as Wearable Proximity Sensor
Authors: Kedambaimoole Vaishakh , Kumar Neelotpala , Shirhatti Vijay , Nuthalapati Suresh , Kumar Saurabh , Nayak Mangalore Manjunatha , Sen Prosenjit , Akinwande Deji , Rajanna Konandur 
Published: March 2021

AbstractThe human body is punctuated with wide array of sensory systems that provide a high evolutionary advantage by facilitating formation of a detailed picture of the immediate surroundings. The sensors range across a wide spectrum, acquiring input from noncontact audiovisual means to contact‐based input via touch and taste. The ambit of sensing can be extended further by imparting the body with increased noncontact sensing capability through the phenomenon of electrostatics. Here, a graphene‐based tattoo sensor is presented for proximity sensing, employing the principle of electrostatic gating. The sensor shows a remarkable change in resistance upon exposure to objects surrounded with static charge on them. Compared to prior work in this field, the sensor demonstrates the highest recorded proximity detection range of 20 cm. It is ultrathin, highly skin conformal, and comes with a facile transfer process such that it can be tattooed on the human skin, unlike other graphene‐based proximity sensors reported before. Present work details the operation of wearable proximity sensor while exploring the effect of mounting body on the working mechanism. A possible role of the sensor as an alerting system against unwarranted contact with objects in public places especially during the current COVID‐19 pandemic is also explored.
Tunable Electroluminescence for Pure White Emission From a Perovskite‐Based LED
Authors: Vashishtha Parth , Brown Alasdair A. M. , Pu Suan Hui , Mhaisalkar Subodh , Mathews Nripan 
Published: March 2021

AbstractHalide perovskite nanocrystals are a promising candidate for lighting applications. However, the production of white light emitting diodes (LEDs) is still a major challenge due to halide ion segregation. In this work, it is demonstrated that reducing the thickness of the perovskite layer in an LED stack can modulate the recombination zone, such that a tunable emission can be obtained. This comprises of an orange electromer emission from a hole‐transport layer (HTL), green electroluminescence from the perovskite active layer, and a blue monomer emission from the same HTL. Overall, a pure white emission can be achieved after successful device optimization, which is particularly challenging for LEDs in which the emission originates solely from perovskite layer. It is anticipated that this methodology could be employed on any type of green‐emitting nanocrystals to fabricate white LEDs.
Cellulose for Light Manipulation: Methods, Applications, and Prospects
Authors: Reimer Martin , Zollfrank Cordt 
Published: March 2021

AbstractCellulose is one of the most abundant biopolymers on earth. It is a sustainable and renewable raw material with many beneficial properties. Due to its availability, nontoxicity, environmental friendliness, biocompatibility, and biodegradability, cellulose is one of the world's most used biopolymers. Cellulose is currently establishing its role as a strong potential candidate for advanced applications in various engineering fields. In addition, cellulose and some of its derivatives exhibit properties, which recommend themselves for use in optical applications and for manipulating light in a targeted manner. In the last decades, efforts were directed toward the production of artificial ordered structures such as photonic crystals, chiral nematic liquid crystals or Bragg stacks, as well as disordered structures such as random lasers from cellulose in order to tailor the interaction of visible light with biopolymers. Due to its sustainable availability and its ability to manage light interactions, cellulose is increasingly used in optoelectronic devices to replace fossil‐based polymers. Cellulose and its derivatives can be consequently applied as optical fibers, probes, organic light emitting diodes, flexible touch screens, and solar cells. The present review provides an overview of the processability and applications of cellulose and its derivatives for the specific manipulation of light.
Market integration and agricultural development: The case of Tibet's ruminant livestock industries
Authors: Brown Colin , Zhang Jing , Zhuoga Deqing , Baiyang Weisi , Yadav Lava 
Published: March 2021

AbstractExpanding livestock production is widely promoted as a way of improving livelihoods of smallholder farmers. However the rudimentary, insular and relatively small size of markets in which many smallholders operate means that rapid livestock industry expansion can have an adverse impact on prices and livelihoods. The link between market integration, livestock industry development and smallholder livelihoods is examined in the case of ruminant livestock industry expansion in Tibet. The analysis finds some transmission between Chinese and Tibetan sheepmeat prices and that this integration with the broader Chinese market and its favourable medium term outlook is crucial to any livestock industry expansion given the current low margins for sheep for Tibetan farmers. While Tibet milk prices exceed eastern China prices, and evidence of transmission is less pronounced, the outcome for smallholder Tibetan dairy farmers in doubling their cow numbers is better in an integrated market than in an insular market. Thus the analysis highlights the importance for ruminant livestock industry expansion in Tibet of integration with broader Chinese markets while also highlighting the need to consider market integration when assessing livestock industry development strategies for smallholder farmers. [EconLit Citations: Q12, Q13]
Equilibrium catalyst from a fluidized catalytic cracking unit separated by metal content by using carbon nanotubes and a biphasic system
Authors: Briggs Nicholas M. , Crossley Steven P. 
Published: March 2021

AbstractDuring fluid catalytic cracking (FCC) operations FCC catalyst particles become contaminated with various metals. These metals impact FCC performance and currently requires equilibrium catalyst (ECAT) mixtures consisting of a blend of FCC particles with a time spent in the reactor ranging from minutes to several months to be continuously extracted and sold as low value products or sent to landfills. Here a unique method to recycle FCC ECAT particles is presented, which separates ECAT particles by metal content by synthesizing carbon nanotubes and nanofibers on the ECAT particles surface and using a biphasic system. ECAT with low metal content can be sent back to the FCC unit for further use while ECAT with high metal content can be used for other purposes. Further, we show these treated ECAT materials of high metals content will absorb oil on the surface of water and may prove useful for oil spill clean‐up applications.
Kinetics simulation of propylene epoxidation over different Ti species in TS‐1
Authors: Zhang Miao , Zuo Yi , Li Tonghui , Liu Min , Yang Hong , Guo Xinwen 
Published: March 2021

AbstractA thorough experimental investigation on the kinetic behavior of liquid‐phase propylene epoxidation over TS‐1 and tetrapropylammonium hydroxide (TPAOH) treated TS‐1 catalysts was conducted in a fixed‐bed reactor. The amounts of different coordinated Ti species in the catalysts were quantified by spectroscopies, and their catalytic performances of the epoxidation and alcoholysis of propylene oxide were measured by kinetic modeling. The study shows that the TPAOH treatment converted some of the tetrahedrally coordinated Ti to octahedrally coordinated Ti, and both species were active for the epoxidation and alcoholysis. The superior catalytic performance observed over the TPAOH treated TS‐1 is due to two factors, the increased percentage of active sites, and reduced energy barrier for epoxidation on the octahedrally coordinated Ti. In addition, as the H2O2 conversion increases, the adsorption equilibrium constant of propylene oxide plays a more decisive role than the activation energy for the selectivity of propylene glycol monomethyl ethers.
Peer‐based interventions targeting suicide prevention: A scoping review
Authors: Bowersox Nicholas W. , Jagusch Jennifer , Garlick James , Chen Jason I. , Pfeiffer Paul N. 
Published: March 2021

AbstractPeers of individuals at risk for suicide may be able to play important roles in suicide prevention. The aim of the current study is to conduct a scoping review to characterize the breadth of peer‐delivered suicide prevention services and their outcomes to inform future service delivery and research. Articles were selected based on search terms related to peers, suicide, or crisis. After reviews of identified abstracts (N = 2681), selected full‐text articles (N = 286), and additional references (N = 62), a total of 84 articles were retained for the final review sample.Types of suicide prevention services delivered by peers included being a gatekeeper, on‐demand crisis support, crisis support in acute care settings, and crisis or relapse prevention. Peer relationships employed in suicide prevention services included fellow laypersons; members of the same sociodemographic subgroup (e.g., racial minority), workplace, or institution (e.g., university, correctional facility); and the shared experience of having a mental condition. The majority of published studies were program descriptions or uncontrolled trials, with only three of 84 articles qualifying as randomized controlled trials. Despite a lack of methodological rigor in identified studies, peer support interventions for suicide prevention have been implemented utilizing a diverse range of peer provider types and functions. New and existing peer‐delivered suicide prevention services should incorporate more rigorous evaluation methods regarding acceptability and effectiveness.
Wild chimpanzee offspring exhibit adult‐like foraging patterns around the age of weaning
Authors: Lonsdorf Elizabeth V. , Stanton Margaret A. , Wellens Kaitlin R. , Murray Carson M. 
Published: March 2021

AbstractObjectivesThe prolonged juvenile period exhibited by primates is an evolutionary conundrum. Here we examine wild chimpanzee feeding development in the context of two hypotheses regarding prolonged development in primates: the needing‐to‐learn hypothesis and the expensive brain hypothesis.Material and MethodsWe studied wild chimpanzee (Pan troglodytes schweinfurthii) offspring at Gombe National Park, Tanzania. We analyzed 41 years of observational behavioral data collected between 1975 and 2016 from 81 offspring. We characterized feeding development in the first 10 years of life via four different measures: (1) proportion of observation time spent feeding; (2) diet composition; (3) diet breadth; and (4) diet maturity as measured by similarity to maternal diet. We used mixed effects models to examine changes with age and by sex, while controlling for season.ResultsFeeding time, diet breadth, and diet maturity exhibited the most substantial increases with age in the first 6 years, with no significant change thereafter. Males and females showed different patterns of change in diet breadth by age, but did not differ by age 10. Diet composition did not change significantly with age and did not differ by sex.DiscussionWe found that chimpanzee offspring attained adult‐like feeding behaviors between 4 and 6 years of age, concomitant with the completion of weaning. Thus, our data do not support the needing‐to‐learn feeding skills hypothesis of a prolonged juvenile period, but additional data are needed to evaluate how and when adolescent chimpanzees are able to make foraging decisions independent of their mothers. Existing data on growth provides support for the expensive brain hypothesis, however, these hypotheses are not necessarily mutually exclusive. As more studies across taxa accumulate sufficient datasets on a range of developmental metrics, we will be able to achieve a more robust understanding of prolonged development in primates.
Nonreciprocal Amplification in Coupled‐Rotating Cavities Around Exceptional Points
Authors: Peng Rui , Zhao Chengsong , Yang Zhen , Xiong Biao , Zhou Ling 
Published: March 2021

AbstractA nonreciprocal‐amplified scheme for signal transmission is proposed in a coupled rotation‐cavity system, where the two cavities rotate with opposite directions, and an optical parametric amplifier (OPA) is attached to one cavity. The coupling between cavities can effectively compensate and enhance the frequency shift of the Sagnac effect, and a perfect nonreciprocity can be achieved. Owing to the introduction of an OPA medium, eigenvalues of the dynamic matrix exhibit exceptional points (EPs), and the amplified‐nonreciprocal transmission can be obtained around EPs.
Enhanced Surface Ligands Reactivity of Metal Clusters by Bulky Ligands for Controlling Optical and Chiral Properties
Authors: Deng Guocheng , Malola Sami , Yuan Peng , Liu Xianhu , Teo Boon K. , Häkkinen Hannu , Zheng Nanfeng 
Published: March 2021

AbstractSurface ligands play critical roles in determining the surface properties of metal clusters. However, modulating the properties and controlling the surface structure of clusters through surface‐capping‐agent displacement is challenging. Herein, [Ag14(SPh(CF3)2)12(PPh3)4(DMF)4] (Ag14‐DMF; DMF=N,N‐dimethylformamide), with weakly coordinated DMF ligands on surface silver sites, was synthesized by a mixed‐ligands strategy. Owing to the high surface reactivity of Ag14‐DMF, the surface ligands are labile, easily dissociated or exchanged by other ligands. Based on the enhanced surface reactivity, easy modulation of the optical properties of Ag14 by reversible “on‐off” DMF ligation was realized. When chiral amines were introduced to as‐prepared products, all eight surface ligands were replaced by amines and the racemic Ag14 clusters were converted to optically pure homochiral Ag14 clusters as evidenced by circular dichroism (CD) activity and single‐crystal X‐ray diffraction (SCXRD). This work provides a new insight into modulation of the optical properties of metal clusters and atomically precise homochiral clusters for specific applications are obtained.
E. coli Nickel‐Iron Hydrogenase 1 Catalyses Non‐native Reduction of Flavins: Demonstration for Alkene Hydrogenation by Old Yellow Enzyme Ene‐reductases**
Authors: Joseph Srinivasan Shiny , Cleary Sarah E. , Ramirez Miguel A. , Reeve Holly A. , Paul Caroline E. , Vincent Kylie A. 
Published: March 2021

AbstractA new activity for the [NiFe] uptake hydrogenase 1 of Escherichia coli (Hyd1) is presented. Direct reduction of biological flavin cofactors FMN and FAD is achieved using H2 as a simple, completely atom‐economical reductant. The robust nature of Hyd1 is exploited for flavin reduction across a broad range of temperatures (25–70 °C) and extended reaction times. The utility of this system as a simple, easy to implement FMNH2 or FADH2 regenerating system is then demonstrated by supplying reduced flavin to Old Yellow Enzyme “ene‐reductases” to support asymmetric alkene reductions with up to 100 % conversion. Hyd1 turnover frequencies up to 20.4 min−1 and total turnover numbers up to 20 200 were recorded during flavin recycling.
Synthese von trifluorierten Tetralinen durch I(I)/I(III)‐katalysierte Ringexpansion: programmieren von Konformationen über [CH2CH2] → [CF2CHF] Isosterismus
Authors: Neufeld Jessica , Stünkel Timo , Mück‐Lichtenfeld Christian , Daniliuc Constantin G. , Gilmour Ryan 
Published: March 2021

AbstractGesättigte, fluorierte Carbocyclen haben sich als wichtiges Gerüst in der heutigen Wirkstoffforschung etabliert. Um das aktuelle Portfolio zu erweitern, wurde eine neue Methode zur Synthese von trifluorierten Tetralinen entwickelt. Fluorierte Methylenindane dienen dabei als geeignete Substrate und unterliegen einer effizienten, difluorierenden Ringexpansion mit in situ erzeugtem p‐TolIF2 (>20 Beispiele, bis zu >95 % Ausbeute). Eine Reihe verschiedener Substituenten wird unter den katalytischen Reaktionsbedingungen toleriert und das Ergebnis wird zusätzlich durch Hammett Analyse bestätigt. Die Röntgenstrukturanalyse zeigt, dass die CH‐F‐Bindung eine pseudoaxiale Orientierung einnimmt, welche mit einer Stabilisierung der σC‐H→σC‐F* Wechselwirkung einhergeht. Das Ersetzen des symmetrischen [CH2‐CH2]‐Motivs durch das nicht‐symmetrische [CF2‐CHF]‐Motiv beseitigt die Konformationsentartung und führt zu einem vorhersagbaren Halbsessel. Die erhaltenen Konformationen dieses neuartigen strukturellen Gleichgewichts wurden durch Computeranalyse untersucht und das Ergebnis steht im Einklang mit der stereoelektronischen Theorie.
Segmented Flow Processes to Overcome Hurdles of Whole‐Cell Biocatalysis in the Presence of Organic Solvents
Authors: Adebar Niklas , Nastke Alina , Löwe Jana , Gröger Harald 
Published: March 2021

AbstractIn modern process development, it is imperative to consider biocatalysis, and whole‐cell catalysts often represent a favored form of such catalysts. However, the application of whole‐cell catalysis in typical organic batch two‐phase synthesis often struggles due to mass transfer limitations, emulsion formation, tedious work‐up and, thus, low yields. Herein, we demonstrate that utilizing segmented flow tools enables the conduction of whole‐cell biocatalysis efficiently in biphasic media. Exemplified for three different biotransformations, the power of such segmented flow processes is shown. For example, a 3‐fold increase of conversion from 34 % to >99 % and a dramatic simplified work‐up leading to a 1.5‐fold higher yield from 44 % to 65 % compared to the analogous batch process was achieved in such a flow process.
Palladium‐Mediated Cγ−H Functionalization of Alicyclic Amines
Authors: Aguilera Ellen Y. , Sanford Melanie S. 
Published: March 2021

AbstractThis paper describes a new method for the transannular functionalization of the γ‐C−H bonds in alicyclic amines to install C(sp3)−halogen, oxygen, nitrogen, boron, and sulfur bonds. The key challenge for this transformation is controlling the relative rate of Cγ−H versus Cα−H functionalization. We demonstrate that this selectivity can be achieved by pre‐complexation of the substrate with Pd prior to the addition of oxidant. This approach enables the use of diverse oxidants that ultimately install various heteroatom functional groups at the γ‐position with high site‐ and diastereoselectivity.
Trifluorinated Tetralins via I(I)/I(III)‐Catalysed Ring Expansion: Programming Conformation by [CH2CH2] → [CF2CHF] Isosterism
Authors: Neufeld Jessica , Stünkel Timo , Mück‐Lichtenfeld Christian , Daniliuc Constantin G. , Gilmour Ryan 
Published: March 2021

AbstractSaturated, fluorinated carbocycles are emerging as important modules for contemporary drug discovery. To expand the current portfolio, the synthesis of novel trifluorinated tetralins has been achieved. Fluorinated methyleneindanes serve as convenient precursors and undergo efficient difluorinative ring expansion with in situ generated p‐TolIF2 (>20 examples, up to >95 %). A range of diverse substituents are tolerated under standard catalysis conditions and this is interrogated by Hammett analysis. X‐ray analysis indicates a preference for the CH−F bond to occupy a pseudo‐axial orientation, consistent with stabilising σC−H→σC−F* interactions. The replacement of the symmetric [CH2−CH2] motif by [CF2−CHF] removes the conformational degeneracy intrinsic to the parent tetralin scaffold leading to a predictable half‐chair. The conformational behavior of this novel structural balance has been investigated by computational analysis and is consistent with stereoelectronic theory.