Strong Charge Research Articles

Interpretation of complex optical properties and optical transitions of epitaxial LaMnO3 thin films

An in-depth analysis of the optical properties of epitaxial (001) oriented LaMnO3films grown on SrTiO3and LaAlO3single crystal substrates is performed by spectroscopic ellipsometry to determine the complex dielectric function (ε = ε1 + iε2) spectra from 0.12 to 5.89 eV. Density Functional Theory and many body perturbation theory within the G0W0 and the Bethe-Salpeter Equation approximations, are also employed to generate theoretical spectra in ε. Critical point energies (CPs) from 0.91 to 1.49 eV are interpreted as energy separation between eg and t2g orbitals. CPs from 3.31 to 3.53 eV and 3.75 to 5.23 are interpreted as Mn d exchange splitting and strong charge transfer transitions, respectively. Direct and indirect bandgaps from Tauc-plots are identified in the range of 0.100–0.594 eV. Anisotropy presents in LaMnO3 on LaAlO3 is attributed to substantial distortion in the out-of-plane epitaxial strain compared to LaMnO3 on SrTiO3. These findings provide a comprehensive understanding of the origins and characteristics of features observed in optical properties of epitaxial LaMnO3, offering insights for development of optical and electronic applications based on these materials.

Rational design of precious tetrametallic single-cluster catalysts for electrocatalytic nitrate reduction reaction

Single cluster catalysts (SCCs) with high metal loading can exhibit extraordinary catalytic activity in electrocatalytic reactions, but the rational design of active sites remains a challenge. Herein, we proposed a series of SCCs with pyramid-shaped precious tetrametallic clusters anchored on g-CN monolayer (M4/g-CN) as efficient catalysts for the electrochemical reduction of nitrate to ammonia (NO3RR). By means of first-principle computations, the stability, catalytic mechanism and activity, as well as selectivity of these SCCs are systematically investigated. The calculation results show that most SCCs (Ru4/g-CN, Rh4/g-CN, Pd4/g-CN, Os4/g-CN, Ir4/g-CN, Pt4/g-CN) are thermodynamically stable due to the strong binding energy and significant charge transfer behavior between tetrametallic clusters and g-CN support. More important, the volcano curve between limiting potentials and adsorption free energy of NO3‾ can be established, in which Ir4/g-CN can exhibit optimal NO3RR activity due to its location of volcano top. Further analysis of electronic structures reveals that the special pyramid configuration can significantly promote the enrichment of charge on active site and elevate its d-band center, and thus facilitates the NO3RR. This finding pours new vigor into the development of the SCCs family.

Kidney targeted delivery of siRNA mediated by peptide-siRNA conjugate for the treatment of acute kidney injury

Small interfering RNA (siRNA), a promising revolutionary therapy, faces delivery obstacles due to its poor targeting, strong charge negativity and macromolecular nature. Clinical-approved siRNAs can now only be delivered to the liver mediated by the chemically conjugated N-acetylgalactosamine (GalNAc) ligand, the conjugate can be effectively uptaken into cells through interaction with asialoglycoprotein receptor (ASGPR) highly expressed on liver hepatocytes. To further explore an efficient non-hepatic targeted delivery strategy, in this study, we designed a delivery system that chemically conjugated p53 siRNA to renal tubular cell-targeting peptides for targeting the kidney, which was suitable for industrial transformation. Results showed that peptide-siRNA conjugate could specifically enter renal tubular epithelial cells and silence targeted genes. In cisplatin-induced acute kidney injury (AKI) mice, peptide-siRNA conjugate blocked the p53-mediated apoptotic pathway and alleviated renal damage. The innovative proposed system to conjugate kidney-targeting peptides with siRNA achieved the efficient kidney-targeted delivery of siRNA and provided a prospective choice for treating AKI.

Design of Ultrasound-Driven Charge Interference Therapy for Wound Infection.

Wound infections, especially those caused by pathogenic bacteria, present a considerable public health concern due to associated complications and poor therapeutic outcomes. Herein, we developed antibacterial nanoparticles, namely, PGTP, by coordinating guanidine derivatives with a porphyrin-based sonosensitizer. The synthesized PGTP nanoparticles, characterized by their strong positive charge, effectively disrupted the bacterial biosynthesis process through charge interference, demonstrating efficacy against both Gram-negative and Gram-positive bacteria. Additionally, PGTP nanoparticles generated reactive oxygen species under ultrasound stimulation, resulting in the disruption of biofilm integrity and efficient elimination of pathogens. RNA-seq analysis unveiled the detailed mechanism of wound healing, revealing that PGTP nanoparticles, when coupled with ultrasound, impair bacterial metabolism by interfering with the synthesis and transcription of amino acids. This study presents a novel approach to combatting wound infections through ultrasound-driven charge-interfering therapy, facilitated by advanced antibacterial nanomaterials.

Substitution Effects on Subcellular Organelle Localization in Live-cell Imaging.

A series of D-p-A indole-containing fluorescent probes were developed followed by an investigation of their photophysical properties and compounds' suitability for subcellular imaging in living cells. We demonstrate that the preference for mitochondrial localization was lost when morpholine was substituted, resulting in the accumulation of the molecule in the lysosomes. However, interestingly, the presence of a nitro group led to their localization within the lipid droplets despite the presence of the morpholine pendant. We also showcase the probes' sensitivity to pH, the influence of added chloroquine, and the temperature response on the changes in fluorescence intensity within lysosomes. The design of the probes with strong intramolecular charge transfer and substantial Stokes shift could facilitate extensive application in various cellular lysosomal models and contribute to a better understanding of the mechanisms involved in stimuli-responsive diseases.

Manipulating Molecular Stacking to Achieve High Electron Mobility in 2D Conjugated Ultra‐Narrow Bandgap Non‐Fullerene Acceptors with Absorption Beyond 1000 nm

AbstractN‐type organic semiconductors are essential for the advancement of organic electronic devices. However, in relation to extensive research on n‐type and p‐type polymers, studies on high‐mobility n‐type small‐molecule semiconductors (SMSCs) are limited. Here, a series of ultra‐narrow bandgap n‐type SMSCs are developed on an A‐D‐A‐type structure. These SMSCs feature an exceptionally large π‐conjugated area, leading to strong intramolecular charge transfer and robust π‐π interactions. For the first time, central core and terminal halogenation are employed to control molecular surface electrostatic potential distribution, thereby regulating the π‐π stacking area (Sπ‐π) and studying their correlation. The research reveals that, in n‐type SMSCs with an edge‐on arrangement, introducing fluorine into the 2D central core can reduce the Sπ‐π, which is detrimental to the electron mobility (µe) of organic field‐effect transistors (OFETs). Conversely, terminal chlorination facilitates electron injection and improves µe. Consequently, DTPC‐OD‐4Cl, featuring shorter alkyl side chains and a non‐fluorinated 2D central core and undergoing terminal chlorination, achieved the highest µe of up to 0.52 cm2 V−1 s−1, ranking among the highest values reported for A‐D‐A type SMSCs. This work not only systematically investigated the influence of molecular structure on mobility but also provided novel insights for designing more efficient n‐type SMSCs.

Fenugreek seed proteins: Ultrasonic‐assisted extraction, characterization, and cupcake application

AbstractIn this study, fenugreek seed proteins were extracted using ultrasonic‐assisted extraction with varying solid:solvent ratios (20–60 g/L) and sonication amplitudes (30%–80%) to determine optimal conditions for the highest extraction yield. The functional, structural, and nutritional characteristics of the protein isolates of fenugreek seeds were investigated. The highest yield (98.74 ± 0.49%) was achieved at a solid:solvent ratio of 43.83 g/L and an amplitude of 67.51%. The coagulated protein values of fenugreek seed protein isolates ranged from ~15.8% to 31.2%, water‐holding capacities ranged from ~2.2 to 3.2 g/g, oil‐holding capacities ranged from ~2.6 to 4.1 g/g, foaming capacities ranged from ~16.3% to 21.3%, foam stabilities ranged from ~59.7% to 78.1%, emulsion stabilities ranged from ~30.2 to 34.5 min, emulsion activities ranged from ~73.8 to 76.8 m2/g, and emulsion capacities ranged from ~26.9% to 30.5% under different extraction conditions. SDS‐PAGE analysis revealed three distinct bands (46, 59, and 80 kDa) for the protein isolates. FT‐IR spectroscopy showed a high presence of β‐sheet structures. The amino acid composition analysis of fenugreek seed protein isolates was determined, revealing richness in essential amino acids (317.97 g amino acid/kg protein isolate). In addition, cupcakes enriched with protein isolates (5%, 10%, and 20% as flour substitutes) were produced, and quality properties such as color change, browning index, moisture content, water activity, baking yield, bulk density, hardness, volume, symmetry, and uniformity indexes were determined. The application of protein isolates in cupcake production demonstrated the potential of fenugreek seeds as valuable ingredients for enhancing the nutritional profile of bakery products.

Efficiency of Alginic Acid, Sodium Carboxymethylcellulose, and Potassium Polyaspartate as Calcium Tartrate Stabilizers in Wines.

The instability of calcium tartrate (CaT) in wines occurs when the effective concentration of ions surpasses the solubility product, leading to the formation of CaT crystals. Unlike potassium hydrogen tartrate (KHT), temperature has little effect on the rate of CaT precipitation, making cold stabilization ineffective. Additives like metatartaric acid and carboxymethylcellulose (CMC) have been used to mitigate this problem, but metatartaric acid's effectiveness is limited due to hydrolysis. Additionally, potassium polyaspartate (KPA), commonly used as a KHT stabilizer, has been reported to reduce wine stability regarding CaT instability. Therefore, exploring alternative stabilization methods is crucial. Alginic acid, permitted as a processing aid in winemaking, can be an alternative to CMC and metatartaric acid due to its strong negative charge and ability to bind calcium ions. This study aimed to assess alginic acid's efficacy as a CaT stabilizer compared to CMC and investigate the impact of KPA on CaT instability. The results showed that KPA did not increase CaT instability and even improved its stability in some wines. Alginic acid outperformed both CMC and KPA in mitigating CaT instability, possibly due to its higher zeta potential and calcium ion complexation ability. This study is the first to investigate the use of alginic acid for CaT stability in wine.

Electron Spin Broken-Symmetry of Fe-Co Diatomic Pairs to Promote Kinetics of Bifunctional Oxygen Electrocatalysis for Zinc-Air Batteries.

Designing bifunctional catalysts to reduce the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) reaction barriers while accelerating the reaction kinetics is perceived to be a promising strategy to improve the performance of Zinc-air batteries. Unsymmetric configuration in single-atom catalysts has attracted attention due to its unique advantages in regulating electron orbitals. In this work, a seesaw effect in unsymmetric Fe-Co bimetallic monoatomic configurations is proposed, which can effectively improve the OER/ORR bifunctional activity of the catalyst. Compared with the symmetrical model of Fe-Co, a strong charge polarization between Co and Fe atoms in the unsymmetric model is detected, in whom the spin-down electrons around Co atoms are much higher than those spin-up electrons. The seesaw effect occurred between Co atoms and Fe atoms, resulting in a negative shift of the d-band center, which means that the adsorption of oxygen intermediates is weakened and more conducive to their dissociation. The optimized reaction kinetics of the catalyst leads to excellent performance in ZABs, with a peak power density of 215mW cm-2 and stable cycling for >1300 h and >4000 cycles. Flexible Zinc-air batteries have also gained excellent performance to demonstrate their potential in the field of flexible wearables.

Alternative approach to baryon masses in the 1/Nc expansion of QCD

The baryon mass operator is studied within a combined expansion in 1/Nc and perturbative SU(3) flavor symmetry breaking, where Nc denotes the number of color charges. Flavor projection operators are used to classify the baryon operators involved in the expansion, which fall into the flavor representations 1, 8, 10+10¯, 27, 35+35¯, and 64. This approach allows one to incorporate up to third-order flavor symmetry breaking in the baryon mass operator in a rigorous and systematic way. Previous work on the subject is considered to validate the approach. A fit to data is performed to evaluate the free parameters in the theory and to produce some numerical values of baryon masses. Results are consistent and reaffirm the striking success of the 1/Nc expansion. Published by the American Physical Society 2024

Erratum: Cubic color charge correlator in a proton made of three quarks and a gluon [Phys. Rev. D 105 , 036007 (2022)]

Erratum: Cubic color charge correlator in a proton made of three quarks and a gluon [Phys. Rev. D <b>105</b> , 036007 (2022)]

Primordial Black Holes with QCD Color Charge.

We describe a realistic mechanism whereby black holes with significant QCD color charge could have formed during the early Universe. Primordial black holes (PBHs) could make up a significant fraction of the dark matter if they formed well before the QCD confinement transition. Such PBHs would form by absorbing unconfined quarks and gluons and hence could acquire a net color charge. We estimate the number of PBHs per Hubble volume with near-extremal color charge for various scenarios and discuss possible phenomenological implications.

Theoretical investigation on the second order nonlinear optical properties of heptagon bridged bi-porphyrin derivatives

Porphyrins and their derivatives have drawn extensive attention as promising nonlinear optical (NLO) materials especially for biological applications owing to its large aromatic conjugation and special biological activity and compatibility. However, it is still critical to strategically design porphyrin derivatives materials with high performance in second order NLO applications and disclose the structure property correlation. In the present work, a series of dual-metallic-porphyrin derivatives are designed by incorporating a heptagon between two porphyrins with further addition of heteroatoms and metals. The doping of B and N along the dipole direction induces large static first hyperpolarizability, and strong charge transfer occurs with further introduction of Mg, thus ultimately achieving excellent second order NLO properties including strong sum frequency generation and difference frequency generations under external fields. The doping of heteroatoms and metals synergistically tunes the electronic structure of porphyrin-based derivatives and brings about high performance in biological nonlinear optics.

Hamiltonian formalism for Bose excitations in a plasma with a non-Abelian interaction I: Plasmon – hard particle scattering

Hamiltonian theory for collective longitudinally polarized gluon excitations (plasmons) interacting with classical high-energy test color-charged particle propagating through a high-temperature gluon plasma is developed. A generalization of the Lie-Poisson bracket to the case of a continuous medium involving bosonic normal field variable ak⁎a and a non-Abelian color charge Qa is performed and the corresponding Hamilton equations are presented. The canonical transformations including simultaneously both bosonic degrees of freedom of the soft collective excitations and degree of freedom of hard test particle connecting with its color charge in the hot gluon plasma are written out. A complete system of the canonicity conditions for these transformations is derived. The notion of the plasmon number density Nkaa1′, which is a nontrivial matrix in the color space, is introduced. An explicit form of the effective fourth-order Hamiltonian describing the elastic scattering of a plasmon off a hard color particle is found and the self-consistent system of Boltzmann-type kinetic equations taking into account the time evolution of the mean value of the color charge of the hard particle is obtained. On the basis of these equations, a model problem of the interaction of two infinitely narrow wave packets is considered. A system of nonlinear first-order ordinary differential equations defining the dynamics of the interaction of the colorless Nkl and color Wkl components of the plasmon number density is derived. The problem of determining the third- and fourth-order coefficient functions entering into the canonical transformations of the original bosonic variable ak⁎a and color charge Qa is discussed. With the help of the coefficient functions obtained, a complete effective amplitude of the elastic scattering of plasmon off hard test particle is written out.

Root nutrition of plants: relevance, needs, problem solving

The article theoretically analyzes the nutrient needs of plants and the balanced supply of macro- and microelements for their proper growth and development. The basis of the research methodology is the systematic approach of assessing the periodicity of foliar feeding of plants with complex preparations of various compositions. It has been established that with foliar fertilization there is a part of nutrients after they enter the plant leaf. Smaller molecules or molecules with less positive charge are more easily transported in the vascular system, from where they move to other parts of the plant, including ammonium, potassium, and urea. On the other hand, larger molecules and ions with a large positive charge tend to stay fairly close to their point of entry because they stick to the negatively charged cell walls. They hold immobile nutrients quite tightly, including calcium, iron, manganese, zinc, and copper. The importance of the combination of biotechnological and ecological aspects in the development and application of complex compounds for foliar fertilization is indicated. The use of compounds based on EDTA is potentially dangerous for agricultural products and the environment. In the long term, this leads to increased pollution of agricultural land, soil degradation, reduced yield, and deterioration of product quality. When applying complex foliar fertilizers, elements with a strong positive charge, such as calcium, do not move very actively in the plant. Accordingly, negatively charged elements, such as phosphorus, slowly enter the leaves of plants. Both elements are relatively stationary after entry. Additional studies have shown that different plant species differ significantly in their ability to absorb nutrients through their leaves. Differences in cuticle thickness, number of pores, and resistance, as well as genetic and environmental factors, all affect a species’ ability to assimilate nutrients applied to leaves.

In situ construction of Ti3+ self-doped TiO2/Ti3C2 Schottky heterojunctions for highly selective photo-Fenton-like degradation of organic pollutants: Surface/interface effect and mechanism insight

The efficient activation of H2O2 in heterogeneous Fenton-like systems is important for the degradation of organic pollutants. Herein, a Ti3C2 MXene catalyst prepared by a simple HF etching method was used to activate H2O2. Ti3+ self-doped TiO2/Ti3C2 MXene (Ti3+-TiO2/Ti3C2) Schottky heterojunctions were in situ constructed in the photo-Fenton-like system. Owing to the Ti3+-TiO2/Ti3C2 Schottky heterojunctions, abundant multivalence titanium species, and strong surface negative charges, the Ti3C2 catalyst exhibited outstanding photo-Fenton-like performances towards the degradation of cationic organic dyes (methylene blue, rhodamine B, basic fuchsin) in a wide pH range of 3.04–10.02. Radical trapping and electron paramagnetic resonance experiments revealed that surface-bound hydroxyl radicals (OH), superoxide radicals (O2−), and photogenerated holes (h+) were the dominant species in the Ti3C2/H2O2/Visible-light system. Density functional theory calculations confirmed that TiO2/Ti3C2 Schottky heterojunctions not only promoted the separation of photogenerated carriers, but also facilitated the desorption of hydroxyl groups (–OH) from the decomposition of H2O2, thereby increasing the yield of reactive species (OH, O2−, and h+).

NIR-II Emissive Superoxide Radical Photogenerator for Photothermal/Photodynamic Therapy against Hypoxic Tumor.

Due to the "Achilles' heels" of hypoxia, complicated location in solid tumor, small molecular photosensitizers with second near-infrared window (NIR-II) fluorescence, type-I photodynamic therapy (PDT), and photothermal therapy (PTT) have attracted great attention. However, these photosensitizers are still few but yet challenging. Herein, an "all in one" NIR-II acceptor-donor-acceptor fused-ring photosensitizer, Y6-Th, is presented for the in-depth diagnosis and efficient treatment of cancer. Benefiting from the strong intramolecular charge transfer, promoted highly efficient intersystem crossing, largely p-conjugated fused-ring structure, and reduced planarity, the fabricated nanoparticles (Y6-Th nanoparticles) can emit NIR-II fluorescence with the peak located at 1020nm, exclusively generate O2•- for type-I PDT, and display excellent PTT performance under an 808nm laser stimulation. These characteristics make Y6-Th a distinguished NIR-wavelength-triggered phototheranostic agent, which can effectively therapy the hypoxic tumor using NIR-II-fluorescence-guided type-I PDT/PTT. This work provides a valuable guideline for fabricating high-performing NIR-II emissive superoxide radical photogenerators.

Non-Metal Doping as a First-Principles Study for Promoting the Hydrogen Evolution of Two-Dimensional Electride Y2C Electrocatalysts

The two-dimensional electrochemical Y2C’s low work function and strong charge transfer qualities limit its applicability in catalysis due to its poor catalytic activity. In this paper, based on density functional theory calculations, we use two techniques to increase the HER catalytic activity of the Y2C monolayer: substitution doping (XC) and adsorption doping (XT) of non-metal (X = N, P, O, S, and F). The results showed that the absolute values of hydrogen free energies (ΔGH*) of the substitutional dopants of PC, SC and adsorptive dopants of NT, OT, ST, and PT had increased catalytic activity compared with those of the pristine Y2C monolayer (−0.673 eV). It was highlighted that the adsorption doping of PT can further reduce the adsorption free energy of the pristine Y2C monolayer to −0.19 eV, which is close to the optimal zero value, and the binding energy of the hydrogen atoms on the Y2C surface significantly increased from −0.913 to −0.438 eV, which is more favorable for the desorption of hydrogen atoms. These results demonstrate that the doping of non-metals activates the adsorption of hydrogen atoms on monolayer Y2C and provides a feasible method for hydrogen generation.

Highly Efficient Luminescent Solar Concentrators Based on BODIPY Derivatives

AbstractThree new chromophores based on difluoroborondipyrromethene dyes (Bodipy‐1, Bodipy‐2, and Bodipy‐3) are used as precursors to prepare luminescent solar concentrators (LSC) based on poly‐acrylate, following a thermally activated polymerization involving lauryl methacrylate as monomer, ethyl glycol dimethacrylate as cross‐linking agent, and lauroyl peroxide as initiator. The new dyes exhibit typical BODIPY absorption and emission properties in dichloromethane fluid solution, assigned to the lower‐lying singlet π–π∗ level, which in the case of Bodipy‐2 and Bodipy‐3, both containing diamino‐substituted styryl subunits in their structure, has a strong charge transfer contribution. The LSCs obtained starting from each of the three Bodipys are interfaced to silicon photovoltaic (PV) cells, and the PV light‐to‐energy conversion efficiencies ηopt for the three systems are calculated. The results yield ηopt of 4.53% for LSC‐Bodipy‐1, 5.26% for LSC‐Bodipy‐2, and 8.23% for LSC‐Bodipy‐3. The optical efficiency for LSC‐Bodipy‐3 is a remarkable value among the LSC based on organic dyes.

Novel A–D–A Type Naphthalenediimide Supramolecule for H2O2 Photosynthesis with Solar‐to‐Chemical Conversion 1.03%

AbstractOrganic supermolecules have shown great promise for photocatalytic hydrogen peroxide (H2O2) production. However, the limitation of intramolecular charge separation efficiency is still a crucial scientific problem. In this study, a novel acceptor–donor–acceptor (A–D–A) type naphthalenediimide supramolecule (SA‐NDI) is successfully designed for overcoming fundamental issues in organic supermolecule. Composed of one electron‐rich core (naphthalenediimide) and two electron‐poor units (aminopyridine), the supramolecule possesses strong intramolecular charge transfer ability. Meanwhile, the SA‐NDI has an obviously stronger internal electric field, which is 2.83 times higher than that of D–A type supramolecule. The A–D–A type SA‐NDI efficiently accelerates charge separation, so that the intramolecular electron quickly migrates to the acceptor for a two‐electron oxygen reduction reaction. The SA‐NDI supramolecule shows excellent H2O2 accumulation ability (13.7 mm) and stable cyclic time above 120 h. Meanwhile, the catalyst exhibits a superior solar‐to‐chemical conversion efficiency of 1.03% under simulated solar irradiation. This work provides an entirely new idea to design an organic supramolecule with an efficient intramolecular charge transfer monomer.