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1.
Nature ; 626(7999): 523-528, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38356068

RESUMEN

Spatial, momentum and energy separation of electronic spins in condensed-matter systems guides the development of new devices in which spin-polarized current is generated and manipulated1-3. Recent attention on a set of previously overlooked symmetry operations in magnetic materials4 leads to the emergence of a new type of spin splitting, enabling giant and momentum-dependent spin polarization of energy bands on selected antiferromagnets5-10. Despite the ever-growing theoretical predictions, the direct spectroscopic proof of such spin splitting is still lacking. Here we provide solid spectroscopic and computational evidence for the existence of such materials. In the noncoplanar antiferromagnet manganese ditelluride (MnTe2), the in-plane components of spin are found to be antisymmetric about the high-symmetry planes of the Brillouin zone, comprising a plaid-like spin texture in the antiferromagnetic (AFM) ground state. Such an unconventional spin pattern, further found to diminish at the high-temperature paramagnetic state, originates from the intrinsic AFM order instead of spin-orbit coupling (SOC). Our finding demonstrates a new type of quadratic spin texture induced by time-reversal breaking, placing AFM spintronics on a firm basis and paving the way for studying exotic quantum phenomena in related materials.

2.
Plant J ; 118(6): 1991-2002, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38549549

RESUMEN

As a major worldwide root crop, the mechanism underlying storage root yield formation has always been a hot topic in sweet potato [Ipomoea batatas (L.) Lam.]. Previously, we conducted the transcriptome database of differentially expressed genes between the cultivated sweet potato cultivar "Xushu18," its diploid wild relative Ipomoea triloba without storage root, and their interspecific somatic hybrid XT1 with medium-sized storage root. We selected one of these candidate genes, IbNF-YA1, for subsequent analysis. IbNF-YA1 encodes a nuclear transcription factor Y subunit alpha (NF-YA) gene, which is significantly induced by the natural auxin indole-3-acetic acid (IAA). The storage root yield of the IbNF-YA1 overexpression (OE) plant decreased by 29.15-40.22% compared with the wild type, while that of the RNAi plant increased by 10.16-21.58%. Additionally, IAA content increased significantly in OE plants. Conversely, the content of IAA decreased significantly in RNAi plants. Furthermore, real-time quantitative reverse transcription-PCR (qRT-PCR) analysis demonstrated that the expressions of the key genes IbYUCCA2, IbYUCCA4, and IbYUCCA8 in the IAA biosynthetic pathway were significantly changed in transgenic plants. The results indicated that IbNF-YA1 could directly target IbYUCCA4 and activate IbYUCCA4 transcription. The IAA content of IbYUCCA4 OE plants increased by 71.77-98.31%. Correspondingly, the storage root yield of the IbYUCCA4 OE plant decreased by 77.91-80.52%. These findings indicate that downregulating the IbNF-YA1 gene could improve the storage root yield in sweet potato.


Asunto(s)
Regulación de la Expresión Génica de las Plantas , Ipomoea batatas , Proteínas de Plantas , Raíces de Plantas , Factor de Unión a CCAAT/genética , Factor de Unión a CCAAT/metabolismo , Ácidos Indolacéticos/metabolismo , Ipomoea batatas/genética , Ipomoea batatas/crecimiento & desarrollo , Ipomoea batatas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raíces de Plantas/genética , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/metabolismo , Plantas Modificadas Genéticamente
3.
Pharm Res ; 41(7): 1521-1531, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38955998

RESUMEN

PURPOSE: Employing polymer additives is an effective strategy to realize the manipulation of polymorphic transformation. However, the manipulation mechanism is still not clear, which limit the precise selection of polymeric excipients and the development of pharmaceutical formulations. METHODS: The solubility of cimetidine (CIM) in acetonitrile/water mixtures were measured. And the polymorphic transformation from CIM form A to form B with the addition of different polymers was monitored by Raman spectroscopy. Furthermore, the manipulation effect of polymers was determined based on the results of experiments and molecular simulations. RESULTS: The solubility of form A is consistently higher than that of form B, which indicate that form B is the thermodynamically stable form within the examined temperature range. The presence of polyvinylpyrrolidone (PVP) of a shorter chain length could have a stronger inhibitory effect on the phase transformation process of metastable form, whereas polyethylene glycol (PEG) had almost no impact. The nucleation kinetics experiments and molecular dynamic simulation results showed that only PVP molecules could significantly decrease the nucleation rate of CIM, due to the ability of reducing solute molecular diffusion and solute-solute molecular interaction. A combination of crystal growth rate measurements and calculations of the interaction energies between PVP and the crystal faces of CIM indicate that smaller molecular weight PVP can suppress crystal growth more effectively. CONCLUSION: PVP K16-18 has more impact on the stabilization of CIM form A and inhibition of the phase transformation process. The manipulation mechanism of polymer additives in the polymorphic transformation of CIM was proposed.


Asunto(s)
Cimetidina , Simulación de Dinámica Molecular , Povidona , Solubilidad , Cimetidina/química , Povidona/química , Polietilenglicoles/química , Polímeros/química , Cristalización , Excipientes/química , Espectrometría Raman , Termodinámica , Cinética , Agua/química
4.
Nano Lett ; 23(12): 5625-5633, 2023 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-37310876

RESUMEN

Kagome superconductors AV3Sb5 (A = K, Rb, Cs) provide a fertile playground for studying intriguing phenomena, including nontrivial band topology, superconductivity, giant anomalous Hall effect, and charge density wave (CDW). Recently, a C2 symmetric nematic phase prior to the superconducting state in AV3Sb5 drew enormous attention due to its potential inheritance of the symmetry of the unusual superconductivity. However, direct evidence of the rotation symmetry breaking of the electronic structure in the CDW state from the reciprocal space is still rare, and the underlying mechanism remains ambiguous. The observation shows unconventional unidirectionality, indicative of rotation symmetry breaking from six-fold to two-fold. The interlayer coupling between adjacent planes with π-phase offset in the 2 × 2 × 2 CDW phase leads to the preferred two-fold symmetric electronic structure. These rarely observed unidirectional back-folded bands in KV3Sb5 may provide important insights into its peculiar charge order and superconductivity.

5.
J Environ Manage ; 352: 120092, 2024 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-38232596

RESUMEN

Heavy metals (HMs) have been widely reported to pose an adverse effect on anaerobic ammonia oxidation (anammox) bacteria, yet the underlying mechanisms remain unclear. This study provides new insights into the potential mechanisms of interaction between HMs and functional enzymes through big date analysis, molecular docking and molecular dynamics simulation. The statistical analysis indicated that 10 mg/L Cu(II) and Cd(II) reduced nitrogen removal rate (NRR) by 85% and 43%, while 5 mg/L Fe(II) enhanced NRR by 29%. Additionally, the results of molecular simulations provided a microscopic interpretation for these macroscopic data. Molecular docking revealed that Hg(II) formed a distinctive binding site on ferritin, while other HMs resided at iron oxidation sites. Furthermore, HMs exhibited distinct binding sites on hydrazine dehydrogenase. Concurrently, the molecular dynamics simulation results further substantiated their capacity to form complexes. Cu(II) displayed the strongest binding affinity with ferritin for -1576 ± 79 kJ/mol in binding free energy calculation. Moreover, Cd(II) bound to ferritin and HDH for -1052.67 ± 58.49 kJ/mol, -290.02 ± 49.68 kJ/mol, respectively. This research addressed a crucial knowledge gap, shedding light on potential applications for remediating heavy metal-laden industrial wastewater.


Asunto(s)
Cadmio , Metales Pesados , Simulación del Acoplamiento Molecular , Oxidación Anaeróbica del Amoníaco , Simulación de Dinámica Molecular , Macrodatos , Metales Pesados/química , Iones , Ferritinas , Oxidación-Reducción , Reactores Biológicos/microbiología , Nitrógeno , Aguas del Alcantarillado , Desnitrificación , Anaerobiosis
6.
Nano Lett ; 22(22): 8827-8834, 2022 Nov 23.
Artículo en Inglés | MEDLINE | ID: mdl-36367457

RESUMEN

The quantum spin Hall (QSH) effect has attracted extensive research interest because of the potential applications in spintronics and quantum computing, which is attributable to two conducting edge channels with opposite spin polarization and the quantized electronic conductance of 2e2/h. Recently, 2M-WS2, a new stable phase of transition metal dichalcogenides with a 2M structure showing a layer configuration identical to that of the monolayer 1T' TMDs, was suggested to be a QSH insulator as well as a superconductor with a critical transition temperature of around 8 K. Here, high-resolution angle-resolved photoemission spectroscopy (ARPES) and spin-resolved ARPES are applied to investigate the electronic and spin structure of the topological surface states (TSS) in the superconducting 2M-WS2. The TSS exhibit characteristic spin-momentum-locking behavior, suggesting the existence of long-sought nontrivial Z2 topological states therein. We expect that 2M-WS2 with coexisting superconductivity and TSS might host the promising Majorana bound states.

7.
Int J Mol Sci ; 24(15)2023 Aug 06.
Artículo en Inglés | MEDLINE | ID: mdl-37569874

RESUMEN

Sucrose synthases (SUS; EC 2.4.1.13) encoded by a small multigene family are the central system of sucrose metabolism and have important implications for carbon allocation and energy conservation in nonphotosynthetic cells of plants. Though the SUS family genes (SUSs) have been identified in several plants, they have not been explored in sweet potato. In this research, nine, seven and seven SUSs were identified in the cultivated sweet potato (Ipomoea batatas, 2n = 6x = 90) as well as its two diploid wild relatives I. trifida (2n = 2x = 30) and I. triloba (2n = 2x = 30), respectively, and divided into three subgroups according to their phylogenetic relationships. Their protein physicochemical properties, chromosomal localization, phylogenetic relationship, gene structure, promoter cis-elements, protein interaction network and expression patterns were systematically analyzed. The results indicated that the SUS gene family underwent segmental and tandem duplications during its evolution. The SUSs were highly expressed in sink organs. The IbSUSs especially IbSUS2, IbSUS5 and IbSUS7 might play vital roles in storage root development and starch biosynthesis. The SUSs could also respond to drought and salt stress responses and take part in hormone crosstalk. This work provides new insights for further understanding the functions of SUSs and candidate genes for improving yield, starch content, and abiotic stress tolerance in sweet potatoes.


Asunto(s)
Ipomoea batatas , Ipomoea batatas/metabolismo , Filogenia , Diploidia , Almidón/metabolismo , Sacarosa/metabolismo , Regulación de la Expresión Génica de las Plantas
8.
Phys Rev Lett ; 129(14): 146401, 2022 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-36240409

RESUMEN

Topological materials have broad application prospects in quantum computing and spintronic devices. Among them, dual topological materials with low dimensionality provide an excellent platform for manipulating various topological states and generating highly conductive spin currents. However, direct observation of their topological surface states still lacks. Here, we reveal the coexistence of the strong and weak topological phases in a quasi-one-dimensional material, TaNiTe_{5}, by spin- and angle- resolved photoemission spectroscopy. The surface states protected by weak topological order forms Dirac-node arcs in the vicinity of the Fermi energy, providing the opportunity to develop spintronics devices with high carrier density that is tunable by bias voltage.

9.
Wei Sheng Yan Jiu ; 51(1): 18-31, 2022 Jan.
Artículo en Zh | MEDLINE | ID: mdl-35341489

RESUMEN

OBJECTIVE: The aim of this paper is to understand the relationship between patterns of adverse childhood experiences(ACEs), screen time and non-suicidal self-injury behaviors(NSSI) among middle school students. METHODS: Stratified cluster sampling method was used to select 14 500 middle school students(7347 boys and 7153 girls; 7247 junior high school students and 7253 senior high school students; 7619 urban students and 6881 rural students) from Shenzhen, Guiyang, Nanchang and Zhengzhou Cities. Questionnaire surveys were conducted using the child abuse questionnaire, household dysfunction questionnaire, non-suicidal self-injury behavior questionnaire and screen time items. The latent class analysis was used to evaluate the ACEs exposure patterns, and multivariable logistic regressions was used to analyze the association between patterns of ACEs, screen time levels and their combined effects with NSSI. RESULTS: Latent class analysis indicated four distinct patterns of ACE exposure: highly ACEs group(6.3%), highly abuse and neglect group(21.4%), lowly ACEs group(26.8%), highly neglect group(45.5%). Those in highly ACEs(OR=4.65, 95%CI 3.73-5.80), highly abuse and neglect(OR=3.43, 95%CI 2.91-4.06) and highly neglect(OR=1.31, 95%CI 1.11-1.55) group had significantly higher risk of NSSI compared with those in lowly ACEs group(P<0.001). In study days(OR=1.72, 95%CI 1.42-2.08) and weekends(OR=1.42, 95%CI 1.27-1.60), high screen time were associated with increased rate of NSSI(P<0.01). There showed a trend toward increased risk of NSSI with increasing ACEs exposure and screen time level(P<0.05). CONCLUSION: High ACEs exposure patterns and high screen time are associated with increased rate of NSSI. Reducing ACEs exposure and controlling screen time is beneficial to the prevention and control of NSSI in middle school students.


Asunto(s)
Experiencias Adversas de la Infancia , Conducta Autodestructiva , Niño , China/epidemiología , Femenino , Humanos , Masculino , Factores de Riesgo , Tiempo de Pantalla , Conducta Autodestructiva/epidemiología , Estudiantes
10.
Phys Rev Lett ; 126(24): 246601, 2021 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-34213928

RESUMEN

The magnetic van der Waals crystals MnBi_{2}Te_{4}/(Bi_{2}Te_{3})_{n} have drawn significant attention due to their rich topological properties and the tunability by external magnetic field. Although the MnBi_{2}Te_{4}/(Bi_{2}Te_{3})_{n} family have been intensively studied in the past few years, their close relatives, the MnSb_{2}Te_{4}/(Sb_{2}Te_{3})_{n} family, remain much less explored. In this work, combining magnetotransport measurements, angle-resolved photoemission spectroscopy, and first principles calculations, we find that MnSb_{4}Te_{7}, the n=1 member of the MnSb_{2}Te_{4}/(Sb_{2}Te_{3})_{n} family, is a magnetic topological system with versatile topological phases that can be manipulated by both carrier doping and magnetic field. Our calculations unveil that its A-type antiferromagnetic (AFM) ground state stays in a Z_{2} AFM topological insulator phase, which can be converted to an inversion-symmetry-protected axion insulator phase when in the ferromagnetic (FM) state. Moreover, when this system in the FM phase is slightly carrier doped on either the electron or hole side, it becomes a Weyl semimetal with multiple Weyl nodes in the highest valence bands and lowest conduction bands, which are manifested by the measured notable anomalous Hall effect. Our work thus introduces a new magnetic topological material with different topological phases that are highly tunable by carrier doping or magnetic field.

11.
Phys Rev Lett ; 127(23): 236401, 2021 Dec 03.
Artículo en Inglés | MEDLINE | ID: mdl-34936772

RESUMEN

Quantum materials with layered kagome structures have drawn considerable attention due to their unique lattice geometry, which gives rise to flat bands together with Dirac-like dispersions. Recently, vanadium-based materials with layered kagome structures were discovered to be topological metals, which exhibit charge density wave (CDW) properties, significant anomalous Hall effect, and unusual superconductivity at low temperatures. Here, we employ angle-resolved photoemission spectroscopy to investigate the electronic structure evolution upon the CDW transition in a vanadium-based kagome material RbV_{3}Sb_{5}. The CDW phase transition gives rise to a partial energy gap opening at the boundary of the Brillouin zone and, most importantly, the emergence of new van Hove singularities associated with large density of states, which are absent in the normal phase and might be related to the superconductivity observed at lower temperatures. Our work sheds light on the microscopic mechanisms for the formation of the CDW and superconducting states in these topological kagome metals.

12.
Polymers (Basel) ; 16(6)2024 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-38543456

RESUMEN

With the rapid growth in the global population and the accelerating pace of urbanization, researching and developing novel strategies for biomass utilization is significant due to its potential for use in renewable energy, climate change mitigation, waste management, and sustainable agriculture. In this environmental context, this review discusses the recent advances in biomass conversion technologies for biochar production, including the first carbonization process and the subsequent activation methods of the biochar derived from lignocellulosic biomass (LBC). Parallel to this, this review deals with other essential parameters in biochar production, such as feedstock types, reaction environments, and operating conditions in the pyrolysis process, to determine the production and composition of LBC. Moreover, the wide-ranging applications of LBC in areas such as adsorption, catalysts, and energy storage are discussed, offering sustainable and environmentally friendly alternatives while reducing reliance on traditional energy sources and mineral resources, thereby providing practical solutions to environmental and energy challenges. Overall, this review not only provides a comprehensive comparative analysis of different LBC preparation methods, but also facilitates a deeper understanding of the advantages and limitations of these methodologies when it comes to developing high-value materials for sustainable applications.

13.
J Hazard Mater ; 477: 135367, 2024 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-39084011

RESUMEN

This study employed spectroscopy, metagenomics, and molecular simulation to investigate the inhibitory effects of Cd(II) and Cu(II) on the anammox system, examining both intracellular and extracellular effects. At concentrations of 5 mg/L, Cd(II) and Cu(II) significantly reduced nitrogen removal efficiency by 41.46 % and 62.03 %, respectively. Additionally, elevated metal concentrations were correlated with decreased extracellular polymeric substances (EPS), thereby reducing their capacity to absorb heavy metals, particularly Cu(II), which decreased from 76.47 % to 14.67 %. Spectral analysis revealed alterations in the secondary structures of EPS induced by Cd(II) and Cu(II), decreasing the ratio of extracellular protein α-helix to (ß-sheet + random coil), which resulted in looser extracellular protein configurations. The results of the metagenomics study showed that the abundance of Candidatus Kuenenia and its genes encoding nitrogen removal-related enzymes was reduced. The abundance of hzs-γ was reduced by 35.09 % at a concentration of 5 mg/L Cu(II). Conversely, genes associated with metal efflux enzymes, like czcR, increased by 54.86 % at 2 mg/L Cd(II). Molecular docking revealed robust bindings of Cd(II) to HZS-α (-342.299 ± 218.165 kJ/mol) and Cu(II) to HZS-γ (-880.934 ± 55.526 kJ/mol). This study elucidated the inhibitory mechanisms of Cd(II) and Cu(II) on the anammox system, providing insights into the resistance of anammox bacteria to heavy metals.


Asunto(s)
Cadmio , Cobre , Matriz Extracelular de Sustancias Poliméricas , Cobre/química , Cadmio/toxicidad , Cadmio/química , Matriz Extracelular de Sustancias Poliméricas/metabolismo , Matriz Extracelular de Sustancias Poliméricas/química , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/genética , Nitrógeno/metabolismo , Metales Pesados/química , Metales Pesados/toxicidad , Contaminantes Químicos del Agua/toxicidad , Contaminantes Químicos del Agua/metabolismo , Contaminantes Químicos del Agua/química , Bacterias/efectos de los fármacos , Bacterias/genética , Bacterias/metabolismo
14.
Carbohydr Res ; 545: 109258, 2024 Sep 12.
Artículo en Inglés | MEDLINE | ID: mdl-39278155

RESUMEN

Although the xylose mutarotation and transformation have been investigated largely separately, their relationship has been rarely systematically elaborated. The effect of several factors such as xylose concentration, temperature, and salt concentration, affecting the mutarotation of xylose are discussed. Nine alkali halides (LiCl, NaCl, KCl, LiBr, NaBr, KBr, LiI, NaI, and KI) are used to test salt effects. The relationship between xylose rotation rate constant (kM), specific optical rotation at equilibrium ([α]eqm), α/ß ratio, H chemical shift difference (ΔΔδ), Gibbs free energy difference (ΔG), hydrogen ion or hydroxide ion concentration ([H+] or [OH-]), and xylose conversion is discussed. Different salts dissolved in water result in different pH of the solutions, which affect the mutarotation of xylose, with the nature of both cation and anion. Shortly, the smaller the cation radius is and the larger the anion radius is, the greater the mutarotation rate is. In the dehydration of xylose to furfural in salty solutions, xylose conversion is positively correlated to mutarotation rate, H+ or OH- concentration, and the energy difference between α-xylopyranose and ß-xylopyranose. Although the [α]eqm of xylose is positively correlated with α/ß configuration ratio, there is no obvious correlation with xylose dehydration. The conversion to furfural in chlorides is superior to that in bromines and iodides, which is due to the fact that the pH of chloride salts is smaller than that of the corresponding bromide and iodized salts. Higher H+ concentration prefers to accelerate the formation of furfural. In basic salt solutions, the xylulose selectivity is higher than that of furfural at the initial stage of reaction. The furfural selectivity and carbon balance are better in acidic condition rather than in basic condition. In H2O-MTHF (2-Methyltetrahydrofuran) biphasic system, the optimal furfural selectivity of 81.0 % is achieved at 190 °C in 1 h with the assistance of LiI and a little HCl (0.2 mmol, 8 mmol/L in aqueous phase). A high mutarotation rate represents rapid xylose conversion, but a high furfural selectivity prefers in acidic solutions, which would be perfect if organic solvents were available to form biphasic systems.

15.
Bioresour Technol ; 406: 131090, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38986880

RESUMEN

To reveal the key enzymes in the nitrogen removal pathway and to further elucidate the mechanism of the catalytic reaction, this study utilized metaproteomics combined with molecular dynamics and density functional theory calculation. K. stuttgartiensis provided the proteins up to 88.37 % in the anammox-based system. Hydrazine synthase (HZS) and hydrazine dehydrogenase (HDH) accounted for 15.94 % and 3.45 % of the total proteins expressed by K. stuttgartiensis, thus were considered as critical enzymes in the nitrogen removal pathway. The process of HZSγ binding to NO with lowest binding free energy of -4.91 ± 1.33 kJ/mol. The reaction catalyzed by HZSα was calculated to be the rate-limiting catalyzing step, because it transferred the proton from NH3 to ·OH by crossing an energy barrier of up to 190.29 kJ/mol. This study provided molecular level insights to enhance the performance of nitrogen removal in anammox-based system.


Asunto(s)
Nitrógeno , Proteómica , Nitrógeno/metabolismo , Proteómica/métodos , Teoría Funcional de la Densidad , Oxidación-Reducción , Proteínas Bacterianas/metabolismo , Anaerobiosis , Catálisis , Simulación de Dinámica Molecular
16.
Artículo en Inglés | MEDLINE | ID: mdl-38193238

RESUMEN

This paper extends a text classification method utilizing natural language processing (NLP) into the field of traditional Chinese medicine (TCM) compound decoction to effectively and scientifically extend the TCM compound decoction duration. Specifically, a TCM compound decoction duration classification named TCM-TextCNN is proposed to fuse multi-dimensional herb features and improve TextCNN. Indeed, first, we utilize word vector technology to construct feature vectors of herb names and medicinal parts, aiming to describe the herb characteristics comprehensively. Second, considering the impact of different herb features on the decoction duration, we use an improved Term Frequency-Inverse Word Frequency (TF-IWF) algorithm to weigh the feature vectors of herb names and medicinal parts. These weighted feature vectors are then concatenated to obtain a multi-dimensional herb feature vector, allowing for a more comprehensive representation. Finally, the feature vector is input into the improved TextCNN, which uses k-max pooling to reduce information loss rather than max pooling. Three fully connected layers are added to generate higher-level feature representations, followed by softmax to obtain the final results. Experimental results on a dataset of TCM compound decoction duration demonstrate that TCM-TextCNN improves accuracy, recall, and F1 score by 5.31%, 5.63%, and 5.22%, respectively, compared to methods solely rely on herb name features, thereby confirming our method's effectiveness in classifying TCM compound decoction duration.

17.
Environ Sci Pollut Res Int ; 31(13): 20488-20498, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38376779

RESUMEN

Anaerobic ammonium oxidation (anammox) sludge is easily deactivated in the process of treating ammonia-laden wastewater. To investigate an effective recovery method, red mud-based biochar carriers (RMBC) were prepared and added to a deactivated anammox reactor; the operation of this reactor had been interrupted for 6 months with starvation and low temperature. The deactivated sludge with added RMBC was recovered rapidly after 31 days, with the specific anammox activity rapidly increasing to 0.84 g N/(g VSS∙day), and the recovery efficiency of nitrogen removal rate increased by four times compared to the unadded control. The granulation degree and extracellular polymeric substances secretion of the anammox sludge with the added RMBC were significantly higher than that of the control group. In addition, a large number of spherical anammox bacteria were observed moored at the porous channels of RMBC, and the copy numbers of functional genes of anammox bacteria were approximately twice that of the control group. Hence, RMBC is a potential sludge activator, and it can provide a "house" to protect anammox bacteria, enhance the metabolic activity and the agglomerative growth of anammox bacteria, and synergistically achieve rapid recovery of deactivated anammox sludge.


Asunto(s)
Compuestos de Amonio , Carbón Orgánico , Aguas del Alcantarillado , Aguas del Alcantarillado/microbiología , Oxidación Anaeróbica del Amoníaco , Oxidación-Reducción , Aguas Residuales , Bacterias/metabolismo , Anaerobiosis , Nitrógeno/metabolismo , Reactores Biológicos/microbiología , Desnitrificación
18.
Nat Commun ; 15(1): 7260, 2024 Aug 23.
Artículo en Inglés | MEDLINE | ID: mdl-39179563

RESUMEN

Sweet potato starch is in high demand globally for food and industry. However, starch content is negatively correlated with fresh yield. It is urgent to uncover the genetic basis and molecular mechanisms underlying the starch yield of sweet potato. Here we systematically explore source-sink synergy-mediated sweet potato starch yield formation: the production, loading, and transport of photosynthates in leaves, as well as their unloading and allocation in storage roots, lead to starch content divergence between sweet potato varieties. Moreover, we find that six haplotypes of IbPMA1 encoding a plasma membrane H+-ATPase are significantly linked with starch accumulation. Overexpression of IbPMA1 in sweet potato results in significantly increased starch and sucrose contents, while its knockdown exhibits an opposing effect. Furthermore, a basic helix-loop-helix (bHLH) transcription factor IbbHLH49 directly targets IbPMA1 and activates its transcription. Overexpression of IbbHLH49 notably improves source-sink synergy-mediated fresh yield and starch accumulation in sweet potato. Both IbbHLH49 and IbPMA1 substantially influence sugar transport and starch biosynthesis in source and sink tissues. These findings expand our understanding of starch yield formation and provide strategies and candidate genes for high starch breeding in root and tuber crops.


Asunto(s)
Regulación de la Expresión Génica de las Plantas , Ipomoea batatas , Hojas de la Planta , Proteínas de Plantas , Raíces de Plantas , Almidón , Ipomoea batatas/genética , Ipomoea batatas/metabolismo , Ipomoea batatas/crecimiento & desarrollo , Almidón/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Raíces de Plantas/metabolismo , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/genética , Hojas de la Planta/metabolismo , Hojas de la Planta/genética , Plantas Modificadas Genéticamente , Haplotipos , Sacarosa/metabolismo , ATPasas de Translocación de Protón/metabolismo , ATPasas de Translocación de Protón/genética
19.
Sci Adv ; 10(25): eadp0575, 2024 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-38896626

RESUMEN

Dirac fermion in topological materials exhibits intriguing nonlinear optical responses. However, their direct correlation with the linearly dispersed band remains elusive experimentally. Here, we take topological semimetal ZrSiS as a paradigm, unveiling three unique nonlinear optical signatures of Dirac fermion. These signatures include strong quadrupolar response, quantum interference effect, and exponential divergent four-wave mixing (FWM), all of which are described by the prominent third-order nonlinear optical susceptibility. Resonantly enhanced by linear bands, quadrupolar second harmonic generation in centrosymmetric bulk overwhelms the electric-dipole contribution at the surface with inherent inversion symmetry breaking. Furthermore, owing to the interference between multiple resonant transition pathways within linear bands, difference-frequency FWM is several orders of magnitude stronger than sum-frequency FWM and third harmonic generation. The difference-frequency FWM further displays an inverse-square divergence toward degenerate excitation, whose scaling law perfectly matches with the long-sought behavior of Dirac fermion. These signatures lay the solid foundation toward the practical applications of topological materials in nonlinear optoelectronics and photonics.

20.
Bioresour Technol ; 412: 131365, 2024 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-39209230

RESUMEN

Camellia oleifera shell (COS) is a renewable biomass resource abundant in lignin with significant potential for producing phenolic monomers. However, the dearth of research has led to considerable resource wastage and environmental pollution. Herein, reductive catalytic fractionation (RCF) of COS was performed using noble metal catalysts in different solvents. An 11.1 wt% yield of phenolic monomers was achieved with 91% selectivity toward propylene-substituted monomers in H2O/EtOH (3:7, v/v) cosolvent under N2 atmosphere. Notably, the highest phenolic monomer yield of 17.0 wt% was obtained with impressive selectivity (86.9%) toward propanol-substituted monomers in the presence of H2. The GPC analysis and 2D HSQC NMR spectra indicated the effective depolymerization of lignin oligomers with catalysts. Phenolic monomers with ethyl, propyl, or propanol side chain could be produced from lignin-derived oligomers through hydrogenolysis, hydrogenation, and decarboxylation reactions. Overall, this study has paved the way for the valorization of COS lignin through the RCF strategy.


Asunto(s)
Camellia , Lignina , Fenoles , Polimerizacion , Solventes , Lignina/química , Catálisis , Solventes/química , Camellia/química , Fenoles/química , Atmósfera/química
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