bluuebunny/crossref_metadata_2025_split huggingface dataset:
Static and Dynamic Disorder of Charge Transfer States Probed by Optical Spectroscopy
Authors: Kahle Frank‐Julian , Rudnick Alexander , Wedler Stefan , Saxena Rishabh , Ammenhäuser Robin , Scherf Ullrich , Bagnich Sergey , Bässler Heinz , Köhler Anna 
Published: February 2022

AbstractSince the key role of charge transfers (CT) states has been identified for organic solar cells (OSCs), research into their properties is a timely topic. Conventionally, their absorption and emission spectra are described in terms of Marcus’ electron transfer theory. This is a single site approach with the essential parameter being the reorganization energy. Thus, it ignores ensemble effects, notably the role of static disorder that is inevitably present in a spin‐coated OSC film. Here time dependent photoluminescence spectroscopy is applied on blends of the polymeric donor MeLPPP with either the non‐fullerene acceptor SF‐PDI2 or with PC61BM within a temperature range from 295 to 5 K. The authors monitor how initially excited singlet states are converted to emissive CT states. Concomitantly, emission from residual singlets on the acceptor is observed rather than hybrid CT‐states. The role of spectral diffusion in this process is discussed. From the temperature and time dependent linewidths of absorption, fluorescence, and CT emission, the static and dynamic contributions to the total disorder are inferred. In both blends, at 295 K, the contribution of static disorder is comparable to the dynamic disorder.
Pd‐Catalyzed Chemoselective Bis‐Allylic Substitution of Allylic Dicarbonates with Arylated Nitromethanes: A Route to 1,2‐Oxazine N‐Oxides
Authors: Zhao Can , Li Tao , Khan Ijaz , Zhang Yong Jian 
Published: February 2022

AbstractAn efficient method for the construction of 1,2‐oxazine N‐oxides has been developed via Pd‐catalyzed chemoselective bis‐allylic substitution of 2‐methylenepropane‐1,3‐diol dicarbonates with arylated nitroalkanes through sequential C‐ and O‐nucleophilic allylic substitution in one‐pot manipulation. By using Pd(PPh3)4 as a catalyst under mild reaction conditions, the process allows rapid access to 3‐aryl‐5,6‐dihydro‐4H‐1,2‐oxazine N‐oxides in high yields with excellent chemoselectivities.
Remote blood collection from older adults in the Brain Health Registry for plasma biomarker and genetic analysis
Authors: Fockler Juliet , Ashford Miriam T. , Eichenbaum Joseph , Howell Taylor , Ekanem Aniekan , Flenniken Derek , Happ Alexander , Truran Diana , Mackin R. Scott , Blennow Kaj , Halperin Eran , Coppola Giovanni , Weiner Michael W. , Nosheny Rachel L. 
Published: February 2022

AbstractIntroductionUse of online registries to efficiently identify older adults with cognitive decline and Alzheimer's disease (AD) is an approach with growing evidence for feasibility and validity. Linked biomarker and registry data can facilitate AD clinical research.MethodsWe collected blood for plasma biomarker and genetic analysis from older adult Brain Health Registry (BHR) participants, evaluated feasibility, and estimated associations between demographic variables and study participation.ResultsOf 7150 participants invited to the study, 864 (12%) enrolled and 629 (73%) completed remote blood draws. Participants reported high study acceptability. Those from underrepresented ethnocultural and educational groups were less likely to participate.DiscussionThis study demonstrates the challenges of remote blood collection from a large representative sample of older adults. Remote blood collection from > 600 participants within a short timeframe demonstrates the feasibility of our approach, which can be expanded for efficient collection of plasma AD biomarker and genetic data.
Cystine Knot Peptides with Tuneable Activity and Mechanism
Authors: Li Choi Yi , Rehm Fabian B. H. , Yap Kuok , Zdenek Christina N. , Harding Maxim D. , Fry Bryan G. , Durek Thomas , Craik David J. , de Veer Simon J. 
Published: February 2022

AbstractKnottins are topologically complex peptides that are stabilised by a cystine knot and have exceptionally diverse functions, including protease inhibition. However, approaches for tuning their activity in situ are limited. Here, we demonstrate separate approaches for tuning the activity of knottin protease inhibitors using light or streptavidin. We show that the inhibitory activity and selectivity of an engineered knottin can be controlled with light by activating a second mode of action that switches the inhibitor ON against new targets. Guided by a knottin library screen, we also identify a position in the inhibitor's binding loop that permits insertion of a biotin tag without impairing activity. Using streptavidin, biotinylated knottins with nanomolar affinity can be switched OFF in activity assays, and the anticoagulant activity of a factor XIIa inhibitor can be rapidly switched OFF in human plasma. Our findings expand the scope of engineered knottins for precisely controlling protein function.
Catalytic Enantioselective Pictet–Spengler Reaction of α‐Ketoamides Catalyzed by a Single H‐Bond Donor Organocatalyst
Authors: Andres Rémi , Wang Qian , Zhu Jieping 
Published: February 2022

AbstractThe asymmetric Pictet–Spengler reaction (PSR) with aldehydes is well known. However, PSR involving ketones as electrophilic partners is far‐less developed. We report herein the first examples of catalytic enantioselective PSR of tryptamines with α‐ketoamides. A new class of easily accessible prolyl‐urea organocatalysts bearing a single H‐bond donor function catalyzes the title reaction to afford 1,1‐disubstituted tetrahydro‐β‐carbolines in excellent yields and enantioselectivities. The kinetic isotope effect using C2‐deuterium‐labelled tryptamine indicates that the rearomatization of the pentahydro‐β‐carbolinium ion intermediate might be the rate‐ and the enantioselectivity‐determining step.
Site‐Specific Protein Modification with Reducing Carbohydrates
Authors: Wu Qifan , Dong Weidong , Miao Hui , Wang Qian , Dong Suwei , Xuan Weimin 
Published: February 2022

AbstractProtein glycosylation plays critical roles in many biological processes. However, the fundamental study and application of glycobiology are hindered by the heterogeneousness of oligosaccharides in natural glycoproteins and the difficulty in constructing glycoproteins of human design. Herein, we describe a semisynthetic method to site‐specifically modify proteins with reducing carbohydrates. The method involves the genetic incorporation of a side‐chain‐esterified aspartate, which was subsequently quantitatively converted into alanine‐β‐hydrazide (Aβz), and chemoselective conjugation of Aβz with a range of readily available reducing carbohydrates. The resulting Aβz‐linked GlcNAc is a close mimic of native N‐GlcNAc and could be installed on various proteins, including IL‐17A and RNase A. Notably, Aβz‐linked GlcNAc on proteins reacted with biantennary oligosaccharide oxazoline derivatives through endoglycosidase‐catalyzed transglycosylation reactions to enable the assembly of homogeneous glycans on proteins.
Host‐Assisted Delivery of a Model Drug to Genomic DNA: Key Information from Ultrafast Spectroscopy and in silico Study
Authors: Ghosh Ria , Singh Soumendra , Mukherjee Dipanjan , Mondal Susmita , Das Monojit , Pal Uttam , Adhikari Aniruddha , Bhushan Aman , Bose Surajit , Bhattacharyya Siddharth Sankar , Pal Debasish , Saha‐Dasgupta Tanusri , Bhattacharyya Maitree , Bhattacharyya Debasis , Mallick Asim Kumar , Das Ranjan , Pal Samir Kumar 
Published: February 2022

AbstractDrug delivery to a target without adverse effects is one of the major criteria for clinical use. Herein, we have made an attempt to explore the delivery efficacy of SDS surfactant in a monomer and micellar stage during the delivery of the model drug, Toluidine Blue (TB) from the micellar cavity to DNA. Molecular recognition of pre‐micellar SDS encapsulated TB with DNA occurs at a rate constant of k1 ∼652 s−1. However, no significant release of encapsulated TB at micellar concentration was observed within the experimental time frame. This originated from the higher binding affinity of TB towards the nano‐cavity of SDS at micellar concentration which does not allow the delivery of TB from the nano‐cavity of SDS micelles to DNA. Thus, molecular recognition controls the extent of DNA recognition by TB which in turn modulates the rate of delivery of TB from SDS in a concentration‐dependent manner.
A Combined Sodium Intercalation and Copper Extrusion Mechanism in the Thiophosphate Family: CuCrP2S6 as Anode Material in Sodium‐Ion Batteries
Authors: van Dinter Jonas , Grantz David , Bitter Alexander , Bensch Wolfgang 
Published: February 2022

AbstractThe layered hypothiophosphate CuCrP2S6 was identified as promising candidate for the application as anode in sodium‐ion batteries exhibiting an appropriate electrochemical performance (409 mAh g−1 after 200 cycles @ 1 A g−1). The electrochemical long‐term experiments suggest that the reaction mechanism changed upon repeated discharging and charging. The initial discharge and charge process was studied by X‐ray diffraction evidencing that at the early discharge stages, Na+ was intercalated into the interlayer space accompanied by a simultaneous reduction of Cu+ to metallic Cu, which was extruded from the host. At later stages of discharge, a conversion of the intermediate phase to Cu0, amorphous Cr0 and P0 embedded in nanocrystalline Na2S occurred. After recharging, only reflections of nanocrystalline NaF could be identified, which is part of the generated solid electrolyte interphase (SEI) layer. In contrast to observation made in literature, elemental Cu seems to be oxidized during the charge process again.
Quantitative Assessment of Ligand Substituent Effects on σ‐ and π‐Contributions to Fe−N Bonds in Spin Crossover FeIIComplexes
Authors: Bondì Luca , Garden Anna L. , Totti Federico , Jerabek Paul , Brooker Sally 
Published: February 2022

AbstractThe effect ofpara‐substituentXon the electronic structure of sixteen tridentate 4‐X‐(2,6‐di(pyrazol‐1‐yl))‐pyridine (bppX) ligands and the corresponding solution spin crossover [FeII(bppX)2]2+complexes is analysed further, to supply quantitative insights into the effect ofXon the σ‐donor and π‐acceptor character of the Fe‐NA(pyridine) bonds. EDA‐NOCV on the sixteenLScomplexes revealed that neitherΔEorb,σ+π(R2=0.48) norΔEorb,π(R2=0.31) correlated with the experimental solution T1/2values (which are expected to reflect the ligand field imposed on the iron centre), but thatΔEorb,σcorrelates well (R2=0.82) and implies that asXchanges fromEDG→EWG(Electron Donating to Withdrawing Group), the ligand becomes a better σ‐donor. This counter‐intuitive result was further probed by Mulliken analysis of theNAatomic orbitals:NA(px) involved in the Fe−N σ‐bond vs. the perpendicularNA(pz) employed in the ligand aromatic π‐system. AsXchangesEDG→EWG, the electron population onNA(pz) decreases, making it a better π‐acceptor, whilst that inNA(px) increases, making it a better σ‐bond donor; both increase ligand field, and T1/2as observed. In 2016, Halcrow, Deeth and co‐workers proposed an intuitively reasonable explanation of the effect of thepara‐Xsubstituents on theT1/2values in this family of complexes, consistent with the calculated MO energy levels, that M→L π‐backdonation dominates in these M−L bonds. Here the quantitative EDA‐NOCV analysis of the M−L bond contributions provides a more complete, coherent and detailed picture of the relative impact of M−L σ‐versus π‐bonding in determining the observed T1/2, refining the earlier interpretation and revealing the importance of the σ‐bonding. Furthermore, our results are in perfect agreement with the ΔE(HS‐LS) vs. σp+(X) correlation reported in their work.
Oxidation of BINOLs by Hypervalent Iodine Reagents: Facile Synthesis of Xanthenes and Lactones
Authors: Zhang Huaiyuan , Wirth Thomas 
Published: February 2022

AbstractXanthene derivatives have broad applications in medicines, fluorescent probes, dyes, food additives, etc. Therefore, much attention was focused on developing the synthetic methods to prepare these compounds. Binaphthyl‐based xanthene derivatives were prepared through the oxidation of BINOLs promoted by the hypervalent iodine reagent iodosylbenzene (PhIO). Nine‐membered lactones were obtained through a similar oxidative reaction when iodoxybenzene (PhIO2) was used. Additionally, one‐pot reactions of BINOLs, PhIO and nucleophiles such as alcohols and amines were also investigated to provide alkoxylated products and amides in good to excellent yields.
Marriage of Heterobuckybowls with Triptycene: Molecular Waterwheels for Separating C60 and C70
Authors: Liu Zhe , Song Wenru , Yang Shaojie , Yuan Chengshan , Liu Zitong , Zhang Hao‐Li , Shao Xiangfeng 
Published: February 2022

AbstractExploration of π‐conjugated polycycles, particularly those have π‐frameworks spread over the three‐dimensional space, is essential in materials science and synthetic chemistry as these chemical entities possess featured optoelectronic properties and supramolecular assembly. Herein, the bowl‐shaped trichalcogenasumanenes are fused onto three branches of triptycene through pyrazine units, affording waterwheel‐like three‐dimensional polycycles 4 a/4 b. Because the three branches on 4 a/4 b are chemically equal, the molecular orbitals of 4 a/4 b show degenerate feature that results in the strong UV‐Vis absorbance at steady state. 4 a/4 b exhibit photo‐induced charge‐separation and subsequent charge‐redistribution at transient state, leading to excited state absorption in NIR‐II window (1165–1400 nm). 4 a/4 b are excellent fullerene receptors, and they form 1 : 1 host‐guest complexes with C60/C70 as proved by spectroscopic titrations and single crystal structure analysis. Moreover, 4 a/4 b show much stronger affinity toward C70 than C60. Consequently, 4 a/4 b are able to separate C60 and C70 from their mixture, giving the purity of C60 up to 99.5 %.
Diradicals Photogeneration from Chloroaryl‐Substituted Carboxylic Acids
Authors: Di Terlizzi Lorenzo , Protti Stefano , Ravelli Davide , Fagnoni Maurizio 
Published: February 2022

AbstractWith the aim of generating new, thermally inaccessible diradicals, potentially able to induce a double‐strand DNA cleavage, the photochemistry of a set of chloroaryl‐substituted carboxylic acids in polar media was investigated. The photoheterolytic cleavage of the Ar−Cl bond occurred in each case to form the corresponding triplet phenyl cations. Under basic conditions, the photorelease of the chloride anion was accompanied by an intramolecular electron‐transfer from the carboxylate group to the aromatic radical cationic site to give a diradical species. This latter intermediate could then undergo CO2 loss in a structure‐dependent fashion, according to the stability of the resulting diradical, or abstract a hydrogen atom from the medium. In aqueous environment at physiological pH (pH=7.3), both a phenyl cation and a diradical chemistry was observed. The mechanistic scenario and the role of the various intermediates (aryl cations and diradicals) involved in the process was supported by computational analysis.
Synthesis of Tetrahydro‐4H‐pyrido[1,2‐b]isoquinolin‐4‐ones from Ugi 4‐CR‐Derived Dihydroisoquinoline‐Xanthates**
Authors: Amador‐Sánchez Yoarhy A. , López‐Mendoza Pedro , Mijangos Marco V. , Miranda Luis D. 
Published: February 2022

AbstractAn efficient protocol for the synthesis of poly‐functionalized 1,2,3,6‐tetrahydro‐4H‐pyrido[1,2‐b]isoquinolin‐4‐ones is described. First, propargyl‐containing Ugi adducts were transformed to polysubstituted dihydroisoquinolines by an intramolecular Au‐catalyzed alkyne hydro‐arylation, followed by the alkene isomerization process. Then, these pivotal intermediates were engaged in a xanthate‐based oxidative radical cascade addition/cyclization process with a suitable alkene.
Oxygen reduction reaction at conducting polymer electrodes in a wider context: Insights from modelling concerning outer and inner sphere mechanisms
Authors: Gueskine Viktor , Vagin Mikhail , Berggren Magnus , Crispin Xavier , Zozoulenko Igor 
Published: February 2022

AbstractPractical interest in oxygen reduction reaction (ORR) has traditionally been due to its application at fuel cells’ cathode following its complete 4e route to the water. In search of new electrode materials, it was discovered that conducting polymers (CPs) also are capable of driving ORR, though predominantly halting the process at 2e reduction leading to hydrogen peroxide generation. As alternative ways to produce this “green oxidant” are attracting increasing attention, a detailed study of the ORR mechanism at CP electrodes gains importance. Here, we summarize our recent theoretical work on the topic, which underscores the fundamental difference between CP and electrocatalytic metal ORR electrodes. Our insights also bring to us the attention of outer‐sphere electron transfer, not unknown but somewhat ignored in the field. We also put the action of CP electrodes in a more general context of chemical ORR and redox mediation responsible for the electrocatalytic ORR mechanism.
Implementation of exactly well‐balanced numerical schemes in the event of shockwaves: A 1D approach for the shallow water equations
Authors: Akbari Majid , Pirzadeh Bahareh 
Published: February 2022

AbstractThis article presents a numerical technique that ensures the exact solution of stationary shockwaves, known as the hydraulic jump, for the one‐dimensional shallow water equations with the geometric source term. The mathematical description of the hydraulic jump is given by the Rankine–Hugoniot condition, at the interface of a control volume, where one variable in the system, the discharge, is supposed to be constant while the remaining variables are discontinuous. However, at the discrete level, the solution could be, for instance, a 3‐state jump, consisting of extra (intermediate) states resulting in the so‐called numerical anomaly. The anomaly is due to the nonlinearity of the Hugoniot locus and the fact that, at these points, a naive formulation is unlikely to avoid the inaccurate representation. The concept used here is simple, limit all discontinuous variables, that is, the surface flow data inside the cell that contains a shock with the data of the nearby cells where the shock is traveling to, allowing the solution to be linear. When used with a number of well‐known numerical solvers, namely Lax–Friedrichs, HLL, and Roe schemes, this approach is confirmed to accurately capture the moving and stationary shockwaves in the trans‐critical flow over nonflat beds.
Nonlinear limits to arbitrage
Authors: Chen Jingzhi , Cai Charlie X. , Faff Robert , Shin Yongcheol 
Published: February 2022

AbstractWe study the nonlinear limits to arbitrage in a model. When mispricing is small, arbitrage activity increases with mispricing because of the higher cost‐adjusted return. However, at high levels of mispricing, arbitrageurs are deterred by larger mispricing as funding constraints become more binding. Testing the model predictions on the index spot‐futures arbitrage with a Markov‐switching model, we document an inverse U‐shaped relationship between mispricing and arbitrage activity. The extreme regime is with the largest mispricing but least arbitrage activity, and coincides with the market turmoil, suggesting that funding constraints become the main driver behind the limit to arbitrage.
Transoral robotic surgery for the identification of unknown primary head and neck squamous cell carcinomas: Its effect on the wait and the weight
Authors: Alzahrani Faisal , Sahovaler Axel , Mundi Neil , Rammal Almoaidbellah , Fnais Naif , MacNeil S. Danielle , Mendez Adrian , Yoo John , Fung Kevin , Laxague Francisco , Warner Andrew , Palma David A. , Nichols Anthony 
Published: February 2022

AbstractBackgroundNeck carcinoma of unknown primary (CUP) is a frequent scenario. Transoral robotic mucosectomies (TORM) of pharynx have increased rate of primary identification, but come with cost of treatment delay.MethodsWe reviewed patients who underwent CUP protocol from 2014 to 2020. Patients with cervical nodes carcinoma and failure to localize a primary source were classified as CUP. We determined primary identification rate and postoperative complications.ResultsWe included 65 patients underwent TORM. Surgical approach consisted of lingual and/or palatine tonsillectomies. The primary detection rate was 49.2%. Average weight reduction was 2.5 ± 4.3 kg. The average number of days from consultation to definitive treatment was 52.2 ± 18.3.ConclusionA systematic approach to patients with CUP showed a promising primary identification rate compared to panendoscopy alone. TORM carries a small risk of complications. The benefits of primary identification must be weighed with the morbidity and delay to definitive treatment.
Relationship between online social support and adolescents’ mental health: A systematic review and meta‐analysis
Authors: Zhou Ziyao , Cheng Qijin 
Published: February 2022

AbstractIntroductionThe potential benefits of supportive interactions on social networking sites on adolescents’ mental health are promising; however, no systematic evaluation has been conducted on this topic. This review examined empirical research on the relationship between social support derived from social networking sites and adolescents’ mental health both theoretically and empirically.MethodsFollowed PRISMA guidelines, we conducted a systematic literature search on six English and three Chinese databases in February 2020. Four thousand one hundred and seventy‐seven articles were screened first by title, then abstract, and lastly, full articles.ResultsFourteen studies (five English and nine Chinese) were identified, with total sample of 11,616 adolescents (age: 10–19 years; females: 42.7%–56.3%). Meta‐analysis showed that the correlation of online social support with self‐esteem was moderate and significant (r = .29), but with depression was small and insignificant (r = −.09). Sensitivity analysis indicated that social support from acquaintances on the internet may not be as beneficial as from real‐life acquaintances. Despite that there isn't enough research on other specific mental health outcomes to run a quantitative synthesis, individual studies suggest that online social support (OSS) may be associated with increased self‐identity and life satisfaction, decreased loneliness and social anxiety, it also counteracts the negative effect of stress and cyberbullying on mental health.ConclusionsOSS might be beneficial for adolescents' mental health, especially self‐esteem, although the causal relationship requires longitudinal studies to confirm, and the underlying mechanisms need further investigation.