bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multiple Helicenes Defected by Heteroatoms and Heptagons with Narrow Emissions and Superior Photoluminescence Quantum Yields**
Authors: Tan Dehui , Dong Jiaqi , Ma Tinghao , Feng Qingliang , Wang Suning , Yang Deng‐Tao 
Published: May 2023

AbstractThe incorporation of heteroatoms and/or heptagons as the defects into helicenes expands the variety of chiroptical materials with novel properties. However, it is still challenging to construct novel boron‐doped heptagon‐containing helicenes with high photoluminescence quantum yields (PLQYs) and narrow full‐width‐at‐half‐maximum (FWHM) values. We report an efficient and scalable synthesis of a quadruple helicene 4Cz‐NBN with two nitrogen‐boron‐nitrogen (NBN) units and a double helicene 4Cz‐NBN‐P1 bearing two NBN‐doped heptagons, the latter could be formed via a two‐fold Scholl reaction of the former. The helicenes 4Cz‐NBN and 4Cz‐NBN‐P1 exhibit excellent PLQYs up to 99 % and 65 % with narrow FWHM of 24 nm and 22 nm, respectively. The emission wavelengths are tunable via stepwise titration experiments of 4Cz‐NBN‐P1 toward fluoride, enabling distinguished circularly polarized luminescence (CPL) from green, orange (4Cz‐NBN‐P1‐F1) to yellow (trans/cis‐4Cz‐NBN‐P1‐F2) with near‐unity PLQYs and broader circular dichroism (CD) ranges. The five structures of the aforementioned four helicenes were confirmed by single crystal X‐ray diffraction analysis. This work provides a novel design strategy for construction of non‐benzenoid multiple helicenes exhibiting narrow emissions with superior PLQYs.
Photochemically‐Driven CO2 Release Using a Metastable‐State Photoacid for Energy Efficient Direct Air Capture
Authors: Premadasa Uvinduni I. , Bocharova Vera , Miles Audrey R. , Stamberga Diana , Belony Stella , Bryantsev Vyacheslav S. , Elgattar Adnan , Liao Yi , Damron Joshua T. , Kidder Michelle K. , Doughty Benjamin , Custelcean Radu , Ma Ying‐Zhong 
Published: May 2023

AbstractOne of the grand challenges underlying current direct air capture (DAC) technologies relates to the intensive energy cost for sorbent regeneration and CO2 release, making the massive scale (GtCO2/year) deployment required to have a positive impact on climate change economically unfeasible. This challenge underscores the critical need to develop new DAC processes with substantially reduced regeneration energies. Here, we report a photochemically‐driven approach for CO2 release by exploiting the unique properties of an indazole metastable‐state photoacid (mPAH). Our measurements on simulated and amino acid‐based DAC systems revealed the potential of mPAH to be used for CO2 release cycles by regulating pH changes and associated isomers driven by light. Upon irradiating with moderate intensity light, a ≈55 % and ≈68 % to ≈78 % conversion of total inorganic carbon to CO2 was found for the simulated and amino acid‐based DAC systems, respectively. Our results confirm the feasibility of on‐demand CO2 release under ambient conditions using light instead of heat, thereby providing an energy efficient pathway for the regeneration of DAC sorbents.
Hybrid Improper Ferroelectricity in Columnar (NaY)MnMnTi4O12
Authors: Scatena Rebecca , Liu Ran , Shvartsman Vladimir V. , Khalyavin Dmitry D. , Inaguma Yoshiyuki , Yamaura Kazunari , Belik Alexei A. , Johnson Roger D. 
Published: May 2023

AbstractWe show that cation ordering on A site columns, oppositely displaced via coupling to B site octahedral tilts, results in a polar phase of the columnar perovskite (NaY)MnMnTi4O12. This scheme is similar to hybrid improper ferroelectricity found in layered perovskites, and can be considered a realisation of hybrid improper ferroelectricity in columnar perovskites. The cation ordering is controlled by annealing temperature and when present it also polarises the local dipoles associated with pseudo‐Jahn–Teller active Mn2+ ions to establish an additional ferroelectric order out of an otherwise disordered dipolar glass. Below TN≈12 K, Mn2+ spins order, making the columnar perovskites rare systems in which ordered electric and magnetic dipoles may reside on the same transition metal sublattice.
Comparative electroanalytical performance of poly o‐toulidine and polyaniline towards hydrazine oxidation supplemented by DFT
Authors: Liaqat Faroha , Jamil Madiha , Tariq Irsa , Haider Ali , Khan Muhammad Abdullah 
Published: May 2023

AbstractThis work presents a comparative experimental and theoretical study on the use of polyaniline and its derivative, poly o‐toluidine, as effective electrochemical sensor for the detection of hydrazine. Hydrazine is a toxic analytic with numerous adverse health effects on the human brain, liver and nervous system. The conducting polymers polyaniline (PANI) and poly o‐toluidine (POT) were synthesized by oxidative polymerization and characterized through x‐ray Diffraction, FT‐IR, and UV–Visible Spectroscopy. Electrochemical studies performed on the polymer modified glassy carbon electrode (GCE) using cyclic voltammetry and differential pulse voltammetry reveal strong interaction between hydrazine and the polymer through irreversible charge transfer. The oxidation current was seen to increase with increasing hydrazine concentration. The diffusion coefficients were found to be 1.89 × 10−5 cm2/s and 2.89 × 10−6 cm2/s for PANI and POT, respectively. PANI and POT based sensors show a limit of detection of 1 μM and 5.13 mM, respectively in the linear concentration range of 1–9 mM. Density functional studies on the PANI‐hydrazine and POT‐hydrazine complexes show enhanced intermolecular charge transfer from nitrogen lone pairs in hydrazine to the polymer backbone clearly identifying the donor and acceptor moieties. PANI based electrochemical sensor is shown to have a higher sensitivity for hydrazine compared to POT, where the sensing interaction is hindered by the bulky methyl group in ortho position.
Synthesis and antimicrobial testing of 5‐fluorouracil derivatives
Authors: Patil Mrunal , Serhii Krykun , Garzino Frédéric , Gobert Quentin , Giorgio Suzanne , Raimundo Jean‐Manuel , Bolla Jean‐Michel , Camplo Michel 
Published: May 2023

AbstractAntibiotic resistance has increased the demand for novel treatments against multidrug‐resistant microorganisms. In the research literature, 5‐fluorouracil (5‐FU) was proposed as an alternative due to its intrinsic antibacterial property. However, given its toxicity profile at high doses, its use in antibacterial therapy is dubious. In the quest for improving the efficacy of 5‐FU, the present study intends to synthesise 5‐FU derivatives and assess their susceptibility and mechanism against pathogenic bacteria. It was found that the compounds having tri‐hexylphosphonium substitution on both nitrogen groups of 5‐FU (6a, 6b and 6c) had considerable activity against both Gram‐positive and Gram‐negative bacteria. Among the active compounds, those with an asymmetric linker group 6c were found to have higher antibacterial efficacy. However, no conclusive efflux inhibition activity was found. As elucidated by electron microscopy studies, these self‐assembling active phosphonium‐based 5‐FU derivatives caused considerable septal damage and cytosolic alterations in Staphylococcus aureus cells. In Escherichia coli, these compounds triggered plasmolysis. Interestingly, the minimal inhibitory concentration (MIC) of the most potent 5‐FU derivative 6c remained constant, regardless of the bacteria's resistance profile. Further analysis revealed that compound 6c generated significant alterations in membrane permeabilization and depolarization in S. aureus and E. coli cells at the MIC. Compound 6c was found to substantially impede bacterial motility, suggesting its importance in regulating bacterial pathogenicity. Additionally, the nonhaemolytic activity of 6c suggested that it could be a potential therapeutic option for treating multidrug‐resistant bacterial infections.
Data analysis for accelerated life tests via Weibull‐gamma frailty regression models
Authors: Zhou Xiao‐Dong , Wang Yun‐Juan , Wu Lin , Yue Rong‐Xian 
Published: May 2023

AbstractIn this article, we study data analysis methods for accelerated life test (ALT) with blocking. Unlike the previous assumption of normal distribution for random block effects, we advocate the use of Weibull regression model with gamma random effects for making statistical inference of ALT data. To estimate the unknown parameters in the proposed model, maximum likelihood estimation and Bayesian estimation methods are provided. We illustrate the proposed methods using real data examples and simulation examples. Numerical results suggest that distribution of random effects has minimal impact on the estimation of fixed effects in the Weibull regression models. Furthermore, to demonstrate the advantage of our proposed model, we also provide methods to compare ALT plans and thus identify the optimal ALT plans.
Recognizing CRISPR as the new age disease‐modifying drug: Strategies to bioengineer CRISPR/Cas for direct in vivo delivery
Authors: Thevendran Ramesh , Maheswaran Solayappan 
Published: May 2023

AbstractClustered regularly interspaced short palindromic repeats (CRISPR) have established itself as a frontier technology in genetic engineering. Researchers have successfully used the CRISPR/Cas system as precise gene editing tools and have further expanded their scope beyond both imaging and diagnostic applications. The most prominent utility of CRISPR is its capacity for gene therapy, serving as the contemporary, disease‐modifying drug at the genetic level of human medical disorders. Correcting these diseases using CRISPR‐based gene editing has developed to the extent of preclinical trials and possible patient treatments. A major impediment in actualizing this is the complications associated with in vivo delivery of the CRISPR/Cas complex. Currently, only the viral vectors (e.g., lentivirus) and non‐viral encapsulation (e.g., lipid particles, polymer‐based, and gold nanoparticles) techniques have been extensively reviewed, neglecting the efficiency of direct delivery. However, the direct delivery of CRISPR/Cas for in vivo gene editing therapies is an intricate process with numerous drawbacks. Hence, this paper discusses in detail both the need and the strategies that can potentially improve the direct delivery aspects of CRISPR/Cas biomolecules for gene therapy of human diseases. Here, we focus on enhancing the molecular and functional features of the CRISPR/Cas system for targeted in vivo delivery such as on‐site localization, internalization, reduced immunogenicity, and better in vivo stability. We additionally emphasize the CRISPR/Cas complex as a multifaceted, biomolecular vehicle for co‐delivery with therapeutic agents in targeted disease treatments. The delivery formats of efficient CRISPR/Cas systems for human gene editing are also briefly elaborated.
Reexamining the Emergence and Stability of the Square Cylinder Phase in Block Copolymers
Authors: Yuan Kangrui , Xu Zhanwen , Huang Xianbo , Li Weihua 
Published: May 2023

AbstractRecently, a few AB‐type multiblock copolymers have been successfully designed to form stable square cylinder phase based on self‐consistent field theory (SCFT) calculations. The previous works only identify the stability region of the square phase but not analyzing its stability, which is closely related to the free‐energy landscape. In this work, we have reexamined the stability of the square phase in
linear pentablock and
star triblock copolymers by drawing the free‐energy landscape with respect to the two dimensions of a rectangular unit cell. Our results demonstrate that the square phase continuously transfers to the rectangular phase as the degree of packing frustration is gradually released. Moreover, the prolate contour lines of the free‐energy landscape indicate the weak stability of the square phase in the
copolymer. In contrast, the stability of the square phase is notably improved in the
copolymer due to its enhanced concentration of bridging configurations. Our work sheds light on the understanding of the stability of the square cylinder phase in block copolymers. Accordingly, we propose some possible strategies for further designing new AB‐type block copolymer systems to obtain more stable square phase.
Construction of Five Tryptophan Isomers and Application of the Isomers to Solid‐Phase Total Syntheses of Lysocin E Derivatives
Authors: Nakata Yosuke , Fu Junhao , Itoh Hiroaki , Panthee Suresh , Hamamoto Hiroshi , Sekimizu Kazuhisa , Inoue Masayuki 
Published: May 2023

AbstractTryptophan (Trp) plays a unique role in peptides and proteins as its indole ring possesses an electron‐rich character and an N1−H hydrogen‐bond donor. Because of its non‐rotationally symmetric structure, synthetic alterations of the orientation of the indole ring would modulate the intrinsic structures and functions of peptides and proteins. Here we developed synthetic routes to the five Trp isomers in which the C3‐substitution of the indole ring was changed to the C2/4/5/6/7‐substitutions, and applied the five monomers to Fmoc‐based solid‐phase peptide synthesis. Specifically, the five monomers were prepared via Negishi cross‐coupling reactions of C2/4/5/6/7‐iodoindoles. To demonstrate the applicability of the monomers to the solid‐phase synthesis, the five Trp isomers of macrocyclic antibiotic lysocin E were selected as target molecules and synthesized through peptide elongation, on‐resin macrocyclization, and global deprotection. The Trp isomers displayed markedly weaker antibacterial activity than the parent natural product, revealing the biological importance of the precise three‐dimensional shape of the original Trp residue of lysocin E. The present methods for the preparation and application of these five Trp isomers provide a new strategy for analyzing and modifying the specific functions of numerous Trp‐containing peptides and proteins beyond this study.
Vibrational Predissociation Spectra of C2N− and C3N−: Bending and Stretching Vibrations
Authors: Dahlmann Franziska , Dinu Dennis F. , Jusko Pavol , Lochmann Christine , Gstir Thomas , Marimuthu Aravindh N. , Liedl Klaus R. , Brünken Sandra , Wester Roland 
Published: May 2023

AbstractWe present infrared predissociation spectra of C2N−(H2) and C 3N−(H2) in the 300–1850 cm−1 range. Measurements were performed using the FELion cryogenic ion trap end user station at the Free Electron Lasers for Infrared eXperiments (FELIX) laboratory. For C2N−(H2), we detected the CCN bending and CC−N stretching vibrations. For the C3N−(H2) system, we detected the CCN bending, the CC−CN stretching, and multiple overtones and/or combination bands. The assignment and interpretation of the presented experimental spectra is validated by calculations of anharmonic spectra within the vibrational configuration interaction (VCI) approach, based on potential energy surfaces calculated at explicitly correlated coupled cluster theory (CCSD(T)‐F12/cc‐pVTZ−F12). The H2 tag acts as an innocent spectator, not significantly affecting the C2,3N− bending and stretching mode positions. The recorded infrared predissociation spectra can thus be used as a proxy for the vibrational spectra of the bare anions.
The Function of Hydrotalcite as a Support Material in the Alcohol‐Assisted Catalytic CO2 Hydrogenation Reaction
Authors: Ye Linlin , Xiao Penny , Webley Paul , Singh Ranjeet , Li Gang Kevin 
Published: May 2023

AbstractThe traditional CO2 hydrogenation reaction in gas phase always requires harsh reaction conditions to activate CO2, resulting in huge energy consumption. However, with the assistance of 1‐butanol solvent, catalytic CO2 hydrogenation can be proceeded at a mild condition of 170 °C and 30 bars. To further improve the catalytic performance of the widely studied Cu‐ZnO‐ZrO2 catalyst (CZZ), the catalysts were modified by incorporating hydrotalcite (HTC) as a support material. The addition of HTC significantly improved the copper dispersion and surface area of the catalyst. The performance of CZZ‐HTC catalysts was investigated at varying weight percentages of HTC, and all showed higher space‐time yield of methanol (STYMeOH) compared to the commercial catalyst. Notably, CZZ‐6HTC exhibited the highest methanol selectivity, further highlighting the beneficial role of HTC as a support material.
Design of a high‐efficiency bandwidth‐enhanced power amplifier based on dual‐paths impedance matching techniques
Authors: Xuan Xuefei , Cheng Zhiqun , Zhang Zhiwei , Gong Tingwei , Liu Guohua , Le Chao 
Published: May 2023

SummaryIn this brief, we propose a bandwidth‐enhanced dual‐paths impedance matching technique that can effectively match the four preset design frequency points in the operating frequency band to the optimal impedance region provided by a series of inverse continuous modes (SICMs), thus realizing the bandwidth expansion and efficiency improvement of the power amplifier (PA). To verify the proposed design theory, a multi‐octave PA component was designed, fabricated, and measured with a 10‐W GaN HEMT device. The implemented PA exhibits superior performance, with a relative bandwidth of 142.9% in the bandwidth range of 0.55–3.3 GHz. Moreover, the 39.1–42 dBm output power, 60.1%–76.2% drain efficiency (DE), and 9.1–12 dB gain are also achieved in the target band. Based on the simulated and measured results, the effectiveness of the proposed design theory is further confirmed.
Individual variation in spawning migration timing in a salmonid fish—Exploring roles of environmental and social cues
Authors: Fukushima Michio , Rand Peter S. 
Published: May 2023

AbstractDescribing and explaining patterns of individual animal behaviors in situ, and their repeatability over the annual cycle, is an emerging field in ecology owing largely to advances in tagging technology. We describe individual movements of adult Sakhalin taimen Parahucho perryi, an endangered salmonid fish, in the headwaters of a river in northern Japan during the spring spawning season over 2 years. Migration timing, separated into stages prior to, during, and following the spawning period, was found to be more consistent and repeatable for females than males. We hypothesized that the observed coordinated movement within seasons, and repeatability in migration timing across seasons, could result from (1) individual‐specific responsiveness resulting from endogenous, biological traits that are mediated by environmental factors, or (2) social interactions among comigrating individuals. We found that water temperature and water level experienced by fish near the river mouth approximately a week before arrival at the spawning ground explained variability in run timing between years for females but not males. We found no evidence of conspecific attraction or repulsion resulting from social interactions among the spawners and post‐spawners. We conclude that individual‐specific responsiveness to environmental cues was the likely mechanism underpinning the observed migration timing and movement patterns.
Tofacitinib treatment of rheumatoid arthritis increases senescent T cell frequency in patients and limits T cell function in vitro
Authors: Alamino Vanina A. , Onofrio Luisina I. , Acosta Cristina del Valle , Ferrero Paola V. , Zacca Estefanía R. , Cadile Isaac I. , Mussano Eduardo D. , Onetti Laura B. , Montes Carolina L. , Gruppi Adriana , Acosta Rodriguez Eva V. 
Published: May 2023

AbstractUnraveling the immune signatures in rheumatoid arthritis (RA) patients receiving various treatment regimens can aid in comprehending the immune mechanisms’ role in treatment efficacy and side effects. Given the critical role of cellular immunity in RA pathogenesis, we sought to identify T‐cell profiles characterizing RA patients under specific treatments.We compared 75 immunophenotypic and biochemical variables in healthy donors (HD) and RA patients, including those receiving different treatments as well as treatment‐free patients. Additionally, we conducted in vitro experiments to evaluate the direct effect of tofacitinib on purified naïve and memory CD4+ and CD8+ T cells.Multivariate analysis revealed that tofacitinib‐treated patients segregated from HD at the expense of T‐cell activation, differentiation, and effector function‐related variables. Additionally, tofacitinib led to an accumulation of peripheral senescent memory CD4+ and CD8+ T cells. In vitro, tofacitinib impaired the activation, proliferation, and effector molecules expression and triggered senescence pathways in T‐cell subsets upon TCR‐engagement, with the most significant impact on memory CD8+ T cells.Our findings suggest that tofacitinib may activate immunosenescence pathways while simultaneously inhibiting effector functions in T cells, both effects likely contributing to the high clinical success and reported side effects of this JAK inhibitor in RA.
MHC I tetramer staining tends to overestimate the number of functionally relevant self‐reactive CD8 T cells in the preimmune repertoire
Authors: Pircher Hanspeter , Pinschewer Daniel D. , Boehm Thomas 
Published: May 2023

AbstractPrevious studies that used peptide‐MHC (pMHC) tetramers (tet) to identify self‐specific T cells have questioned the effectiveness of thymic‐negative selection. Here, we used pMHCI tet to enumerate CD8 T cells specific for the immunodominant gp33 epitope of lymphocytic choriomeningitis virus glycoprotein (GP) in mice transgenically engineered to express high levels of GP as a self‐antigen in the thymus. In GP‐transgenic mice (GP+), monoclonal P14 TCR+ CD8 T cells that express a GP‐specific TCR could not be detected by gp33/Db‐tet staining, indicative of their complete intrathymic deletion. By contrast, in the same GP+ mice, substantial numbers of polyclonal CD8 T cells identifiable by gp33/Db‐tet were present. The gp33‐tet staining profiles of polyclonal T cells from GP+ and GP‐negative (GP−) mice were overlapping, but mean fluorescence intensities were ∼15% lower in cells from GP+ mice. Remarkably, the gp33‐tet+ T cells in GP+ mice failed to clonally expand after lymphocytic choriomeningitis virus infection, whereas those of GP− mice did so. In Nur77GFP‐reporter mice, dose‐dependent responses to gp33 peptide‐induced TCR stimulation revealed that gp33‐tet+ T cells with high ligand sensitivity are lacking in GP+ mice. Hence, pMHCI tet staining identifies self‐specific CD8 T cells but tends to overestimate the number of truly self‐reactive cells.
Interferon‐α regulates abnormally increased expression of RSAD2 in Th17 and Tfh cells in systemic lupus erythematosus patients
Authors: Xin Yue , He Zhenghao , Mei Yang , Li Xi , Zhao Zhidan , Zhao Mingming , Yang Ming , Wu Haijing 
Published: May 2023

AbstractSystemic lupus erythematosus (SLE) is a chronic autoimmune disease that often involves abnormal activation of regulatory IFN genes and regulation of B cells by CD4+ T cells. Radical S‐adenosyl methionine domain containing 2 (RSAD2) is a viral suppressor protein regulated by type I IFN, and it has been proven to play an important regulatory role in SLE. However, the mechanism by which RSAD2 participates in the pathogenesis of SLE is unclear. In this study, we observed higher expression levels of RSAD2 in CD4+ T‐cell subsets from the peripheral blood of SLE patients than in those from healthy controls by bioinformatics analysis and validation experiments. We analyzed the expression of RSAD2 in CD4+ T cells of patients with SLE and other autoimmune diseases. In addition, we found that the expression of RSAD2 in CD4+ T cells might be regulated by IFN‐α, and RSAD2 significantly affected the differentiation of Th17 cells and T follicular helper (Tfh) cells. Our findings underlined that RSAD2 may promote B‐cell activation by promoting the differentiation of Th17 and Tfh cells in SLE patients, a process that is regulated by IFN‐α.