bluuebunny/crossref_metadata_2025_split huggingface dataset:
Testing dark energy with supernovae
Authors: Kowalski M. 
Published: June 2022

AbstractThe use of Type Ia Supernovae as cosmic standard candles pose still perhaps the most direct way to probe the Cosmic acceleration history. In this contribution we will review the present status of Supernova cosmology. We will focus on current observations and what they can tell us about the properties of Dark Energy, i.e. our (in‐)ability to distinguish dark energy models from cosmological constant. In the last part we will give a brief outlook at what to expect from future surveys.
Metric‐affine f(R)‐gravity with torsion: an overview
Authors: Capozziello S. , Vignolo S. 
Published: June 2022

AbstractTorsion and curvature could play a fundamental role in explaining cosmological dynamics. f(R)‐gravity with torsion is an approach aimed to encompass in a comprehensive scheme all the Dark Side of the Universe (Dark Energy and Dark Matter). We discuss the field equations in empty space and in presence of perfect fluid matter taking into account the analogy with the metric‐affine formalism. The result is that the extra curvature and torsion degrees of freedom can be dealt under the standard of an effective scalar field of fully geometric origin. The initial value problem for such theories is also discussed.
On the energy conditions in non‐compact Kaluza‐Klein gravity
Authors: Rasouli S.M.M. , Jalalzadeh S. 
Published: June 2022

AbstractWe investigate a few cosmological solutions in non‐compact five‐dimensional space‐time which is both Ricci‐flat and conformally flat. We then study the reduced solutions on the brane in detail by applying the four energy conditions, which categorize our model in some classes. These classes of solutions can describe the universe including accelerating expansion with either abnormal matter (when matter specifically violates the strong energy condition, it is called abnormal) or a phantom model of dark energy and a Stephani universe which is dominated by abnormal matter describing vacuum energy.
On the initial condition in quantum cosmology
Authors: Pedram P. 
Published: June 2022

AbstractWe outline the applications of a new initial condition for the Wheeler‐DeWitt equation in various quantum cosmology models. These models consist of minimally coupled scalar field in Friedmann‐Robertson‐Walker and Stephani spacetimes, varying speed of light theories and conformally coupled scalar field in Friedmann‐Robertson‐Walker spacetime. This initial condition results in wave packets with complete classical and quantum correspondence. This means that the wave packets closely follow the classical trajectories and strongly peak on them. We show that these models, similar to their classical counterparts, contain singularities even at the quantum level.
Bianchi I model of the universe in terms of nonstandard LQC
Authors: Dzierżak P. , Piechocki W. 
Published: June 2022

AbstractWe apply the loop geometry underlying loop quantum cosmology to examine the cosmological singularity of the Bianchi I model. Modification of classical theory by holonomy around a loop turns a big‐bang into a big‐bounce already at the classical level. Our model has a free parameter to be determined by cosmic data.
Generalization of Hajicek and Kuchař's canonical quantization scheme to the 3+1 geometries admitting maximally symmetric two‐dimensional surfaces
Authors: Melas E. 
Published: June 2022

AbstractThe 3+1 (canonical) decomposition of all geometries admitting two‐dimensional space‐like surfaces is exhibited. A proposal consisting of a specific re‐normalization Assumption and an accompanying Requirement is put forward, which enables the canonical quantization of these geometries. The resulting Wheeler–deWitt equation is based on a re‐normalized manifold parameterized by three smooth scalar functionals and the entire space of solutions to this equation is analytically given.
Propagation of extended objects across singularity of time dependent orbifold
Authors: Małkiewicz P. 
Published: June 2022

AbstractIn this paper we argue that the compactified Milne space is a promising model of the cosmological singularity. It is shown that extended objects like strings propagate in a well‐defined manner across the singularity of the embedding space. Then a proposal for quantization of extended objects in the case of a membrane is given.
Presently decaying dark energy?
Authors: Shafieloo A. , Sahni V. , Starobinsky A.A. 
Published: June 2022

AbstractInvestigation of dark energy (DE) properties using the largest existing Constitution supernovae sample including recent CfA data for small redshifts and omitting the assumption of a constant equation of state w for DE reveals a slight inconsistency (more than 1σ) with the standard spatially flat LCDM model. The effect which is most clearly seen using the recently introduced Om diagnostic corresponds to an increase of both this diagnostic and w at redshifts z <∼ 0.3. Interestingly, such DE behaviour produces a better fit to baryon acoustic oscillation data too. Including the cosmic microwave background shift parameter as another independent observation, we have shown that the well known CPL parametrization is not suitable to fit the data at low and high redshifts simultaneously because of this non‐trivial DE behaviour implied by them. If not systematic, this effect would correspond to DE decaying into dark matter or something else presently, and we have found good consistency of a toy model for this process with the data.
Three steps to accelerated expansion
Authors: Hrycyna O. , Szydłowski M. 
Published: June 2022

AbstractWe study the dynamics of a non‐minimally coupled scalar field cosmology with a potential function. We use the framework of dynamical systems theory to investigate all evolutional paths admissible for all initial conditions. Additionally, we assume the presence of barotropic matter and show that the dynamics can be formulated in terms of an autonomous dynamical system. We have found fixed points corresponding to three main stages of the evolution of the universe, namely, radiation, matter and quintessence domination epochs. Using the linearization of the dynamical systems in the vicinity of the critical points we explicitly obtain formulas determining the effective equation of state parameter for the universe at different epochs. In our approach the form of w(z) parametrisation is derived directly from the dynamical equations rather than postulated a priori.
Weak lensing forecasts for dark energy, neutrinos and initial conditions
Authors: Debono I. , Rassat A. , Réfrégier A. , Amara A. , Kitching T.D. 
Published: June 2022

AbstractWeak gravitational lensing provides a sensitive probe of cosmological parameters by measuring the mass distribution and the geometry of the low redshift universe. We show how an all‐sky weak lensing tomographic survey can jointly constrain different sets of cosmological parameters describing dark energy, massive neutrinos, and the primordial power spectrum. Using the Fisher matrix formalism with and without CMB priors, we examine how the constraints vary as the parameter set is enlarged. We find that weak lensing with CMB priors provides robust constraints on dark energy parameters and can simultaneously provide strong constraints on all three parameter sets. We also find that the dark energy sector is largely insensitive to the inclusion of the other cosmological sectors.
Statistical anisotropy as a consequence of inflation
Authors: Shtanov Y. 
Published: June 2022

AbstractCosmological inflation remains to be a unique mechanism of generation of plausible initial conditions in the early universe. In particular, it generates the primordial quasiclassical perturbations with power spectrum determined by the fundamental principles of quantum field theory. In this work, we pay attention to the fact that the quasiclassical perturbations permanently generated at early stages of inflation break homogeneity and isotropy of the cosmological background. The evolution of the small‐scale quantum vacuum modes on this inhomogeneous background results in statistical anisotropy of the primordial power spectrum, which can manifest itself in the observable large‐scale structure and cosmic microwave background. The effect is predicted to have almost scale‐invariant form dominated by a quadrupole and may serve as a non‐trivial test of the inflationary scenario. Theoretical expectation of the magnitude of this statistical anisotropy depends on the assumptions about the physics in the trans‐Planckian region of wavenumbers.
PPN limit and cosmological gravitational waves as tools to constrain f(R)‐gravity
Authors: De Laurentis M. , Capozziello S. , Nojiri S. , Odintsov S.D. 
Published: June 2022

AbstractWe discuss the PPN Solar‐System constraints and the GW stochastic background considering some recently proposed f(R) gravity models which satisfy both cosmological and stability conditions. Using the definition of PPN‐parameters γand β in terms of f(R)‐models and the definition of scalar GWs, we compare and discuss if it is possible to search for parameter ranges of f(R)‐models working at Solar System and GW stochastic background scale.
Galactic halos in cosmology with long‐range scalar DM interaction
Authors: Hellwing W.A. 
Published: June 2022

AbstractBased on a set of cosmological N‐body simulations we analyze properties of the dark matter (DM) haloes in a galaxy mass range (1011–1013 h‐1Modot) in modified ΛCDM cosmology with additional dynamically screened scalar interactions in DM sector. Our simulations show that scalar interactions support picture of the Island Universe. Rapid structure formation processes are shifted into higher redshifts resulting in a much smaller accretion and merging rates for galactic haloes at low redshifts. Finally, we present how this “fifth” force affects halo properties, like density profile, triaxiality, ellipticities and the spin parameter.
Convergent Synthesis and Anti‐Pancreatic Cancer Cell Growth Activity of a Highly Branched Heptadecasaccharide from Carthamus tinctorius
Authors: Hu Chaoyu , Wu Shengjie , He Fei , Cai Deqin , Xu Zhuojia , Ma Wenjing , Liu Yating , Wei Bangguo , Li Tiehai , Ding Kan 
Published: June 2022

AbstractBioactive polysaccharides from natural resources target various biological processes and are increasingly used as potential target molecules for drug development. However, the accessibility of branched and long complex polysaccharide active domains with well‐defined structures remains a major challenge. Herein we describe an efficient first total synthesis of a highly branched heptadecasaccharide moiety of the native bioactive galectin‐3‐targeting polysaccharide from Carthamus tinctorius L. as well as shorter fragments of the heptadecasaccharide. The key feature of the approach is that a photo‐assisted convergent [6+4+7] one‐pot coupling strategy enables rapid assembly of the heptadecasaccharide, whereby a photoremovable o‐nitrobenzyl protecting group is used to generate the corresponding acceptor for glycosylation in situ upon ultraviolet radiation. Biological activity tests suggest that the heptadecasaccharide can target galectin‐3 and inhibit pancreatic cancer cell growth.
Synthetic Reprogramming of Kinases Expands Cellular Activities of Proteins
Authors: Shoba Veronika M. , Munkanatta Godage Dhanushka N. P. , Chaudhary Santosh K. , Deb Arghya , Siriwardena Sachini U. , Choudhary Amit 
Published: June 2022

AbstractPhosphorylation‐inducing chimeric small molecules (PHICS) can enable a kinase to act at a new cellular location or phosphorylate non‐native substrates (neo‐substrates)/ sites (neo‐phosphorylations).[1, 2] We report a modular design and high‐yielding synthesis of such PHICS that endowed multiple new activities to protein kinase C (PKC). For example, while PKC is unable to downregulate the activity of a gain‐of‐function variant (S180A) of Bruton's tyrosine kinase that evokes B cell malignancy phenotype, PHICS enabled PKC to induce inhibitory neo‐phosphorylations on this variant. Furthermore, while PKC typically phosphorylates its membrane‐associated substrates, PKC with PHICS phosphorylated multiple cytosol‐based neo‐substrates (e.g., BCR‐ABL). Finally, a PHICS for BCR‐ABL induced death of chronic myeloid leukemia cell lines. These studies show the power of synthetic chemistry to expand the chemical and functional diversity of proteins in cells using bifunctional molecules.
Restoration of the Immunogenicity of Tumor Cells for Enhanced Cancer Therapy via Nanoparticle‐Mediated Copper Chaperone Inhibition
Authors: Ding Feixiang , Li Fei , Tang Dongsheng , Wang Bin , Liu Junyan , Mao Xiaoyuan , Yin Jiye , Xiao Haihua , Wang Jing , Liu Zhaoqian 
Published: June 2022

AbstractRecent progress in studying copper‐dependent targets and pathways in the context of tumor treatment has provided new insights into therapeutic strategies of leveraging copper‐dependent disease vulnerabilities and pharmacological manipulation of intratumor copper transportation to improve chemotherapy. Here, we developed reactive oxygen species (ROS)‐sensitive nanoparticles loaded with copper chaperone inhibitor DC_AC50 and cisplatin(IV) prodrug. The released DC_AC50 can promote a remarkable accumulation of intracellular cisplatin and copper through inhibition of the Atox1‐ATPase pathways, thereby enhancing the chemotherapeutic effect of cisplatin and inducing significant ROS generation. Excessive ROS then elicits intense endoplasmic reticulin (ER) stress which facilitates the immunogenic cell death (ICD) spurring a sustained immune response. Our study suggests that nanoparticle‐mediated copper chaperone inhibition via DC_AC50 can restore the immunogenicity of tumor cells for enhanced chemotherapy and cancer immunotherapy.
Highly Robust CuI‐TADF Emitters for Vacuum‐Deposited OLEDs with Luminance up to 222 200 cd m−2 and Device Lifetimes (LT90) up to 1300 hours at an Initial Luminance of 1000 cd m−2
Authors: Tang Rui , Xu Shuo , Lam Tsz‐Lung , Cheng Gang , Du Lili , Wan Qingyun , Yang Jun , Hung Faan‐Fung , Low Kam‐Hung , Phillips David Lee , Che Chi‐Ming 
Published: June 2022

AbstractA critical step in advancing the practical application of copper‐based organic light‐emitting diodes (OLEDs) is to bridge the large gap between device efficiency and operational stability at practical luminance. Described is a panel of air‐ and thermally stable two‐coordinate CuI emitters featuring bulky pyrazine‐ (PzIPr) or pyridine‐fused N‐heterocyclic carbene (PyIPr*) and carbazole (Cz) ligands with enhanced amide‐Cu‐carbene bonding interactions. These CuI emitters display thermally activated delayed fluorescence (TADF) from the 1LL′CT(Cz→PzIPr/PyIPr*) excited states across the blue to red regions with exceptional radiative rate constants of 1.1–2.2×106 s−1. Vapour‐deposited OLEDs based on these CuI emitters showed excellent external quantum efficiencies and luminance up to 23.6 % and 222 200 cd m−2, respectively, alongside record device lifetimes (LT90) up to 1300 h at 1000 cd m−2 under our laboratory conditions, highlighting the practicality of the CuI‐TADF emitters.
Exploration of potential inhibitors for SARS‐CoV‐2 Mpro considering its mutants via structure‐based drug design, molecular docking, MD simulations, MM/PBSA, and DFT calculations
Authors: Ghasemlou Abdulrahman , Uskoković Vuk , Sefidbakht Yahya 
Published: June 2022

AbstractThe main protease (Mpro) of SARS‐COV‐2 plays a vital role in the viral life cycle and pathogenicity. Due to its specific attributes, this 3‐chymotrypsin like protease can be a reliable target for the drug design to combat COVID‐19. Since the advent of COVID‐19, Mpro has undergone many mutations. Here, the impact of 10 mutations based on their frequency and five more based on their proximity to the active site was investigated. For comparison purposes, the docking process was also performed against the Mpros of SARS‐COV and MERS‐COV. Four inhibitors with the highest docking score (11b, α‐ketoamide 13b, Nelfinavir, and PF‐07321332) were selected for the structure‐based ligand design via fragment replacement, and around 2000 new compounds were thus obtained. After the screening of these new compounds, the pharmacokinetic properties of the best ones were predicted. In the last step, comparative molecular dynamics (MD) simulations, molecular mechanics Poisson–Boltzmann surface area calculations (MM/PBSA), and density functional theory calculations were performed. Among the 2000 newly designed compounds, three of them (NE1, NE2, and NE3), which were obtained by modifications of Nelfinavir, showed the highest affinity against all the Mpro targets. Together, NE1 compound is the best candidate for follow‐up Mpro inhibition and drug development studies.
Thermoluminescence characteristics of calcite with a Gaussian process regression model of machine learning
Authors: Isik Esme 
Published: June 2022

AbstractThermoluminescence (TL) is defined as a luminescence phenomenon that can be detected when an insulator or semiconductor is thermally stimulated. Defective crystals store radiation until they are stimulated. Thermoluminescence is a method of monitoring the absorbed dose of dosimeters. The irradiation crystal is heated to 500°C to display the absorbed dose as a luminescent light. The TL dosimetric properties of calcite obtained from nature were investigated in this study. Machine learning was also examined using Gaussian process regression (GPR) for stimulated TL characteristics. According to the experimental output, the TL glow curve had two main peaks located at 90°C and 240°C with good dosimetric properties. In the four regression models of GPR, the data for the heating rate of 3°C s−1have the lowest residual.
Biofabricated macrophage and fibroblast membranes synergistically promote skin wound healing
Authors: Wang Dongqing , Chen Heying , Lei Li , Chen Jun , Gao Jimin , Liu Jiahe , Li Qianyin , Xie Yajun , Hu Yi , Ni Yilu 
Published: June 2022

AbstractEffective skin wound healing is a complex process involving anti‐inflammation, fibrosis, matrix reconstruction, and angiogenesis. This work aimed to integrate the macrophage‐mediated anti‐inflammation and fibroblast‐assisted matrix reconstruction for enhanced skin wound healing. Herein, we utilized the cytomembranes derived from repolarized M2 macrophages and fibroblasts to prepare the natural biologics. Results showed that the inflammatory M1 macrophages were repolarized to M2 phenotype by the M2 macrophage cytomembranes. As a consequence, the cytomembranes of M2 macrophage could facilitate the wound closure in mice. Furthermore, the addition of fibroblast membranes to the macrophage cytomembranes contributed to a better matrix reconstruction, neovascularization and angiogenesis. Next, we used a transforming growth factor‐β (TGF‐β) inhibitor to attenuate cutaneous scar formation. Therefore, our modality could promote skin wound healing and effectively suppress scar formation in the preclinical murine skin wounds. The cytomembrane biologics might provide a biocompatible and versatile tool for wound healing.
Turning adversity into opportunity: Small extracellular vesicles as nanocarriers for tumor‐associated macrophages re‐education
Authors: Donoso‐Meneses Dario , Figueroa‐Valdés Aliosha I. , Georges Nicolás , Tobar Hugo E. , Alcayaga‐Miranda Francisca 
Published: June 2022

AbstractCurrently, small extracellular vesicles (sEV) as a nanoscale drug delivery system, are undergoing biotechnological scaling and clinical validation. Nonetheless, preclinical pharmacokinetic studies revealed that sEV are predominantly uptaken by macrophages. Although this “sEV‐macrophage” propensity represents a disadvantage in terms of sEV targeting and their bioavailability as nanocarriers, it also represents a strategic advantage for those therapies that involve macrophages. Such is the case of tumor‐associated macrophages (TAMs), which can reprogram/repolarize their predominantly immunosuppressive and tumor‐supportive phenotype toward an immunostimulatory and anti‐tumor phenotype using sEV as nanocarriers of TAMs reprogramming molecules. In this design, sEV represents an advantageous delivery system, providing precision to the therapy by simultaneously matching their tropism to the therapeutic cell target. Here, we review the current knowledge of the role of TAMs in the tumoral microenvironment and the effect generated by the reprogramming of these phagocytic cells fate using sEV. Finally, we discuss how these vesicles can be engineered by different bioengineering techniques to improve their therapeutic cargo loading and preferential uptake by TAMs.
New Spiro‐Sesquiterpenoids from the Marine Sponge Myrmekioderma sp.
Authors: Zhou Mei‐Hong , Luo Xiang‐Chao , Zhao Hui‐Min , Lu Jing‐Rong , Dai Ying , Yu Yong , Zhang Liang , Lin Hou‐Wen , Yang Fan 
Published: June 2022

AbstractThree new spiro‐sesquiterpenoids, myrmekiones A−C (1–3), were isolated from the marine sponge Myrmekioderma sp. collected from the South China Sea. The structures of 1–3 were experimentally illuminated though comprehensive NMR spectra, X‐ray diffraction analysis and calculated ECD. These three compounds possessed a special spiro skeleton. Compound 1 was characterized by a chamigrane‐type structure, it is the first time to obtain the single‐crystal of this type of oil compounds. 2 and 3 were a pair of diastereoisomers that possessed an acorane skeleton. This study expands the chemical diversity of marine origin spiro‐metabolites.
Exploring the Temperature Effect on Enantioselectivity of a Baeyer‐Villiger Biooxidation by the 2,5‐DKCMO Module: The SLM Approach
Authors: Röllig Robert , Paul Caroline E. , Duquesne Katia , Kara Selin , Alphand Véronique 
Published: June 2022

AbstractTemperature is a crucial parameter for biological and chemical processes. Its effect on enzymatically catalysed reactions has been known for decades, and stereo‐ and enantiopreference are often temperature‐dependent. For the first time, we present the temperature effect on the Baeyer‐Villiger oxidation of rac‐bicyclo[3.2.0]hept‐2‐en‐6‐one by the type II Bayer‐Villiger monooxygenase, 2,5‐DKCMO. In the absence of a reductase and driven by the hydride‐donation of a synthetic nicotinamide analogue, the clear trend for a decreasing enantioselectivity at higher temperatures was observed. “Traditional” approaches such as the determination of the enantiomeric ratio (E) appeared unsuitable due to the complexity of the system. To quantify the trend, we chose to use the ‘Shape Language Modelling’ (SLM), a tool that allows the reaction to be described at all points in a shape prescriptive manner. Thus, without knowing the equation of the reaction, the substrate ee can be estimated that at any conversion.