We introduce an exact-two-component complete active space self-consistent-field (X2C-CASSCF) method formulated under the restricted-magnetic-balance condition. This framework allows for the nonperturbative treatment of static magnetic fields using gauge-including atomic orbitals (GIAOs). The GIAO-X2C-CASSCF methodology effectively captures all microstates within the same 2 + 1-degenerate manifold and their splitting in a static magnetic field, which are not accessible through single-reference-based methods.
View Article and Find Full Text PDFDendrimers are branched polymers with wide applications to photosensitization, photocatalysis, photodynamic therapy, photovoltaic conversion, and light sensor amplification. The primary step of numerous photophysical and photochemical processes in many molecules involves ultrafast coherent electronic dynamics and charge oscillations triggered by photoexcitation. This electronic wavepacket motion at short times where the nuclei are frozen is known as attosecond charge migration.
View Article and Find Full Text PDFThe direct imaging of time-evolving molecular charge densities on atomistic scale and at femtosecond resolution has long been an elusive task. In this theoretical study, we propose a self-heterodyne electron diffraction technique based on single electron pulses. The electron is split into two beams, one passes through the sample and its interference with the second beam produces a heterodyne diffraction signal that images the charge density.
View Article and Find Full Text PDFThe direct probing of photochemical dynamics by detecting the electronic coherence generated during passage through conical intersections is an intriguing challenge. The weak coherence signal and the difficulty in preparing purely excited wave packets that exclude coherence from other sources make it experimentally challenging. We propose to use time-resolved X-ray magnetic circular dichroism to probe the wave packet dynamics around the conical intersection.
View Article and Find Full Text PDFFlavonoids have been shown to play an essential role in plant growth and fertility. 4-Coumarate CoA ligase (4CL) is one of the indispensable enzymes involved in the biosynthesis of flavonoids. However, the role of 4CL and flavonoids in impact on cotton fertility is still unknown.
View Article and Find Full Text PDFHomosporous lycophytes (Lycopodiaceae) are a deeply diverged lineage in the plant tree of life, having split from heterosporous lycophytes ( and ) ~400 Mya. Compared to the heterosporous lineage, Lycopodiaceae has markedly larger genome sizes and remains the last major plant clade for which no chromosome-level assembly has been available. Here, we present chromosomal genome assemblies for two homosporous lycophyte species, the allotetraploid and the diploid .
View Article and Find Full Text PDFBifidobacteria as a strictly anaerobic gram-positive bacteria, is widely distributed in the intestine, vagina and oral cavity, and is one of the first gut flora to colonize the early stages of life. Intestinal flora is closely related to health, and dysbiosis of intestinal flora, especially Bifidobacteria, has been found in a variety of diseases. Numerous studies have shown that in addition to maintaining intestinal homeostasis, Bifidobacteria may be involved in diseases covering all parts of the body, including the nervous system, respiratory system, genitourinary system and so on.
View Article and Find Full Text PDFAmomi Fructus (Sharen, AF) is a traditional Chinese medicine (TCM) from three source species (or varieties), including var. (WVV), var. (WVX), or (WL).
View Article and Find Full Text PDFFuture breeding is likely to involve the detection and removal of deleterious alleles, which are mutations that negatively affect crop fitness. However, little is known about the prevalence of such mutations and their effects on phenotypic traits in the context of modern crop breeding. To address this, we examined the number and frequency of deleterious mutations in 350 elite maize inbred lines developed over the past few decades in China and the United States.
View Article and Find Full Text PDFThe ultrafast electronic charge dynamics in molecules upon photoionization while the nuclear motions are frozen is known as charge migration. In a theoretical study of the quantum dynamics of photoionized 5-bromo-1-pentene, we show that the charge migration process can be induced and enhanced by placing the molecule in an optical cavity, and can be monitored by time-resolved photoelectron spectroscopy. The collective nature of the polaritonic charge migration process is investigated.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
May 2023
In this theoretical study, we show how photoelectron signals generated by time-energy entangled photon pairs can monitor ultrafast excited state dynamics of molecules with high joint spectral and temporal resolutions, not limited by the Fourier uncertainty of classical light. This technique scales linearly, rather than quadratically, with the pump intensity, allowing the study of fragile biological samples with low photon fluxes. Since the spectral resolution is achieved by electron detection and the temporal resolution by a variable phase delay, this technique does not require scanning the pump frequency and the entanglement times, which significantly simplifies the experimental setup, making it feasible with current instrumentation.
View Article and Find Full Text PDFVariational treatment of the Dirac-Coulomb-Gaunt or Dirac-Coulomb-Breit two-electron interaction at the Dirac-Hartree-Fock level is the starting point of high-accuracy four-component calculations of atomic and molecular systems. In this work, we introduce, for the first time, the scalar Hamiltonians derived from the Dirac-Coulomb-Gaunt and Dirac-Coulomb-Breit operators based on spin separation in the Pauli quaternion basis. While the widely used spin-free Dirac-Coulomb Hamiltonian includes only the direct Coulomb and exchange terms that resemble nonrelativistic two-electron interactions, the scalar Gaunt operator adds a scalar spin-spin term.
View Article and Find Full Text PDFMultiple sclerosis (MS) is an autoimmune, inflammatory demyelinating disorder of the central nervous system. Accumulating evidence has underscored the therapeutic potential of bone marrow mesenchymal stem cells (BMSCs)-derived exosomes (BMSC-Exos) containing bioactive compounds in MS. Herein, the current study sought to characterize the mechanism of BMSC-Exos harboring miR-367-3p both in BV2 microglia by Erastin-induced ferroptosis and in experimental autoimmune encephalomyelitis (EAE), a typical animal model of MS.
View Article and Find Full Text PDFMultiple sclerosis (MS) is a chronic autoimmune disease that affects the central nervous system and is marked by inflammation and damage to the myelin sheath surrounding nerve fibers. Recent studies have highlighted the therapeutic value of exosomes (Exos) obtained from bone marrow mesenchymal stem cells (BMSCs) in MS treatment. These BMSC-Exos contain biologically active molecules that show promising results in preclinical evaluations.
View Article and Find Full Text PDFThe fully correlated frequency-independent Dirac-Coulomb-Breit Hamiltonian provides the most accurate description of electron-electron interaction before going to a genuine relativistic quantum electrodynamics theory of many-electron systems. In this work, we introduce a correlated Dirac-Coulomb-Breit multiconfigurational self-consistent-field method within the frameworks of complete active space and density matrix renormalization group. In this approach, the Dirac-Coulomb-Breit Hamiltonian is included variationally in both the mean-field and correlated electron treatment.
View Article and Find Full Text PDFWe show how ultrafast gas-phase X-ray and electron diffraction signals can be combined to generate real-space movies of charge migration dynamics in molecules. Charge migration denotes short time electronic charge redistribution upon photoexcitation of molecules where the nuclei are frozen. In this regime, we identify a mixed electronic-nuclear interference term that can be cleanly singled out.
View Article and Find Full Text PDFArgonaute proteins exist widely in eukaryotes and prokaryotes, and they are of great potential for molecular cloning, nucleic acid detection, DNA assembly, and gene editing. However, their overall properties are not satisfactory and hinder their broad applications. Herein, we investigated a prokaryotic Argonaute nuclease from a mesophilic bacterium (CdAgo) and explored its overall properties, especially with 5'-hydroxylated (5'-OH) guides.
View Article and Find Full Text PDFConstructing a coupling interface of multicomponents with different functions is of considerable importance for designing an advanced bifunctional water splitting electrode. Particularly, designing and developing alloy/oxyhydroxide-integrated electrodes have emerged as a tendency yet remain a considerable challenge. In this work, a novel 3D nanostructure electrocatalyst assembled from CoRu nanoalloy and CrOOH nanosheets (denoted as CoRu-CrOOH/NF) was directly grown on nickel foam via a successive hydrothermal method.
View Article and Find Full Text PDFThe coherent ring current of Mg-phthalocyanine created by a broad band UV-visible pump pulse shows variation with time, where the ring currents at the corner benzene rings, around the Mg cation and on the outer ring oscillate with different time periods and the current density migrates among these regions. The 7 pairs of degenerate excited states populated upon photoexcitation, generate 21 distinct coherent ring currents. We further calculate the time-resolved X-ray circular dichroism (TRXCD) spectrum of the coherences contributing to the ring current obtained by an attosecond X-ray probe pulse resonant with the nitrogen K-edge.
View Article and Find Full Text PDFCoumarins are natural products with important medicinal values, and include simple coumarins, furanocoumarins and pyranocoumarins. Female ginseng (Angelica sinensis) is a renowned herb with abundant coumarins, originated in China and known for the treatment of female ailments for thousands of years. The molecular basis of simple coumarin biosynthesis in A.
View Article and Find Full Text PDFThe frequency-independent Coulomb-Breit operator gives rise to the most accurate treatment of two-electron interaction in the non-quantum-electrodynamics regime. The Breit interaction in the Coulomb gauge consists of magnetic and gauge contributions. The high computational cost of the gauge term limits the application of the Breit interaction in relativistic molecular calculations.
View Article and Find Full Text PDFHydrogen energy with the advantages of green, sustainability, and high energy density has been considered as an alternative to fossil fuel energy. Water electrolysis to produce hydrogen is a promising energy conversion technology but limited to the large overpotential; thus, a highly efficient electrocatalyst is urgently needed. Herein, Ru-based electrocatalysts including an ultrathin Ru/three-dimensional (3D) macropore N-doped carbon framework (Ru/3DMNC) and ultrathin RuO/3D macropore N-doped carbon framework (RuO/3DMNC) are first prepared using a Zn-centered metal-organic framework (MOF, ZIF-8) as the precursor.
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