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1.
Nat Prod Rep ; 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38651516

RESUMO

Covering: 1993 to the end of 2022As the rapid development of antibiotic resistance shrinks the number of clinically available antibiotics, there is an urgent need for novel options to fill the existing antibiotic pipeline. In recent years, antimicrobial peptides have attracted increased interest due to their impressive broad-spectrum antimicrobial activity and low probability of antibiotic resistance. However, macromolecular antimicrobial peptides of plant and animal origin face obstacles in antibiotic development because of their extremely short elimination half-life and poor chemical stability. Herein, we focus on medium-sized antibacterial peptides (MAPs) of microbial origin with molecular weights below 2000 Da. The low molecular weight is not sufficient to form complex protein conformations and is also associated to a better chemical stability and easier modifications. Microbially-produced peptides are often composed of a variety of non-protein amino acids and terminal modifications, which contribute to improving the elimination half-life of compounds. Therefore, MAPs have great potential for drug discovery and are likely to become key players in the development of next-generation antibiotics. In this review, we provide a detailed exploration of the modes of action demonstrated by 45 MAPs and offer a concise summary of the structure-activity relationships observed in these MAPs.

2.
Molecules ; 29(7)2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-38611953

RESUMO

Bacterial virulence factors and biofilm development can be controlled by the quorum-sensing (QS) system, which is also intimately linked to antibiotic resistance in bacteria. In previous studies, many researchers found that quorum-sensing inhibitors (QSIs) can affect the development of bacterial biofilms and prevent the synthesis of many virulence factors. However, QSIs alone have a limited ability to suppress bacteria. Fortunately, when QSIs are combined with antibiotics, they have a better therapeutic effect, and it has even been demonstrated that the two together have a synergistic antibacterial effect, which not only ensures bactericidal efficiency but also avoids the resistance caused by excessive use of antibiotics. In addition, some progress has been made through in vivo studies on the combination of QSIs and antibiotics. This article mainly expounds on the specific effect of QSIs combined with antibiotics on bacteria and the combined antibacterial mechanism of some QSIs and antibiotics. These studies will provide new strategies and means for the clinical treatment of bacterial infections in the future.


Assuntos
Antibacterianos , Infecções Bacterianas , Humanos , Antibacterianos/farmacologia , Infecções Bacterianas/tratamento farmacológico , Percepção de Quorum , Biofilmes , Fatores de Virulência
3.
J Sci Food Agric ; 2024 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-38372364

RESUMO

BACKGROUND: Distiller's grains (DGs), which are rich in natural ingredients such as prolamins, are often used as low-value feed or discarded directly, resulting in great environmental pollution and resource waste. Prolamins from DGs (PDGs) were found to be a potential material for the construction of biopolymer films due to their good film-forming properties. In this study, extrusion processing was conducted to modify the physicochemical and structural properties of PDGs to facilitate the construction of biopolymer films with superior characteristics. RESULTS: Results indicated that extrusion led to improved solubility (17.91% to 39.95%) and increased disulfide bonds (1.46 to 6.13 µmol g-1 ) in PDGs. The total and sulfur amino acid contents of extruded PDGs were increased by 13.26% and 38.83%, respectively. New aggregation patterns were formed after extrusion according to the results of scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. Extrusion resulted in reduced surface hydrophobicity of PDGs (10 972 to 3632), sufficient evidence for which could be also found from structure analyses of PDGs. Finally, PDGs extruded at 110 °C were found to facilitate the forming of biopolymer films with superior mechanical properties, water resistance and thermal stability. CONCLUSIONS: Physicochemical and structural properties of PDGs were effectively modified by extrusion processing, and extrusion modification of PDGs could be a great way to facilitate the construction of biopolymer films with superior characteristics. It could provide more possibilities to extend the applications of DGs to alleviate the problems of environmental pollution and resource waste. © 2024 Society of Chemical Industry.

4.
Transl Oncol ; 41: 101887, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38262112

RESUMO

BACKGROUND: The progression and metastasis of tumors are typically accompanied by angiogenesis. Crucially, vascular endothelial growth factor (VEGF) and its receptors (VEGFRs) play a significant role in tumor-associated angiogenesis. In this study, the aim was to investigate the antitumor effect of combining bevacizumab (Bev) with anlotinib (An) on colorectal cancer (CRC). METHODS: The CCK-8 assay, EdU assay, and Annexin V staining were conducted to evaluate the proliferation and apoptosis of CRC cells in vitro. The migration capability of CRC cells and HUVECs was assessed using the Transwell assay. Additionally, the tube formation capability of HUVECs was investigated. Furthermore, the antitumor and antiangiogenic effects were evaluated in the BALB/c mice model using immunohistochemistry, TUNEL staining, and 18F-FDG PET/CT imaging. Finally, we analyzed the inhibitory effect of Bev and/or An on related signaling effectors through western blotting. RESULTS: The in vivo CRC mice model revealed that the combination of Bev + An significantly suppressed tumor formation and angiogenesis. Bev + An inhibited tumor glucose metabolism and increased the median survival period in tumor-bearing mice. Mechanistically, the expressions of VEGF, VEGFR2, PDGFR, and FGFR, as well as the phosphorylation levels of AKT, were inhibited after Bev+An treatment. In conclusion, the dual vertical targeting of VEGF and VEGFR in the CRC mice model strongly inhibited tumor growth and angiogenesis, with the suppression of the AKT signaling pathway playing a partial role.

5.
Front Immunol ; 14: 1265959, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37818373

RESUMO

Background: The optimal local treatment for HCC with tumor diameter ≥ 5 cm is not well established. This research evaluated the effectiveness of external beam radiation therapy (EBRT) versus transcatheter arterial chemoembolization (TACE) for HCC with tumor diameter ≥ 5 cm. Methods: A total of 1210 HCC patients were enrolled in this study, including 302 and 908 patients that received EBRT and TACE, respectively. Propensity score matching (PSM) was used to identify patient pairs with similar baseline characteristics. Overall survival (OS) was the primary study endpoint. Results: We identified 428 patients using 1:1 PSM for survival comparison. Compared with the TACE group, the EBRT group had a significantly longer median OS (mOS) before (14.9 vs. 12.3 months, p = 0.0085) and after (16.8 vs. 11.4 months, p = 0.0026) matching. In the subgroup analysis, compared with the TACE group, the EBRT group had a significantly longer mOS for HCC with tumor diameters of 5-7 cm (34.1 vs. 14.3 months, p = 0.04) and 7-10 cm (34.4 vs. 10 months, p = 0.00065), whereas for HCC with tumor diameters ≥ 10 cm, no significant difference in mOS was observed (11.2 vs. 11.2 months, p = 0.83). In addition, the multivariable Cox analysis showed that Child-A, alkaline phosphatase < 125 U/L, and EBRT were independent prognostic indicators for longer survival. Conclusion: EBRT is more effective than TACE as the primary local treatment for HCC with tumor diameter ≥ 5 cm, especially for HCC with tumor diameter of 5-10 cm.


Assuntos
Carcinoma Hepatocelular , Quimioembolização Terapêutica , Neoplasias Hepáticas , Humanos , Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/patologia , Terapia Combinada , Estudos Retrospectivos
6.
Appl Microbiol Biotechnol ; 107(22): 6937-6947, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37704770

RESUMO

The rapid and efficient consumption of carbon and nitrogen sources by brewer's yeast is critical for the fermentation process in the brewing industry. The comparison of the growth characterizations of typical ale and lager yeast, as well as their consumption preference to carbon and nitrogen sources were investigated in this study. Results showed that the ale strain grew faster and had a more extended stationary phase than the lager strain. However, the lager strain was more tolerant to the stressful environment in the later stage of fermentation. Meanwhile, the ale and lager yeast strains possessed varying preferences for metabolizing the specific fermentable sugar or free amino acid involved in the wort medium. The lager strain had a strong capacity to synthesize the extracellular invertase required for hydrolyzing sucrose as well as a strong capability to metabolize glucose and fructose. Furthermore, the lager strain had an advantage in consuming Lys, Arg, Val, and Phe, whereas the ale strain had a higher assimilation rate in consuming Tyr. These findings provide valuable insights into selecting the appropriate brewer's yeast strain based on the wort components for the industrial fermentation process. KEY POINTS: • The lager strain is more tolerant to the stressful environment. • The lager strain has the great capability to synthesize the extracellular invertase. • The assimilation efficiency of free amino acid varies between ale and lager.

7.
Int J Biol Macromol ; 253(Pt 2): 126840, 2023 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-37696374

RESUMO

The interactions between potato starch (PtS) and barley ß-glucan (BBG) were investigated by preparing PtS-BBG mixtures, and the pasting, rheological, gelling and structural properties were evaluated. Rapid viscosity analysis suggested that BBG reduced the peak and breakdown viscosity, while increasing the setback viscosity of PtS. PtS-12%BBG showed the lowest leached amylose content (12.02 ± 0.36 %). The particle size distribution pattern of PtS was not changed with the addition of BBG, and the median diameter of PtS-12%BBG (88.21 ± 0.41 µm) was smaller than that of PtS (108.10 ± 6.26 µm). Rheological results showed that PtS and PtS-BBG gels exhibited weak gel behaviors, and BBG could remarkably affect the elastic and viscous modulus of PtS gels. Textural analysis suggested that the strength and hardness of PtS gels were increased when few BBG (<6 %, w/w) was present in the system. BBG improved the freeze-thaw stability of PtS gels. Structural analysis indicated that hydrogen bonds were the main force in the PtS-BBG systems. These results indicated that BBG interacted with starch via hydrogen bonds, which delayed starch gelatinization and improved gelling properties of PtS gels. Overall, this study gained insights into starch-polysaccharide interactions and revealed the possible applications of BBG in food processing.


Assuntos
Hordeum , Solanum tuberosum , beta-Glucanas , Amido/química , Géis/química , Viscosidade , Reologia
8.
Gene ; 877: 147542, 2023 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-37279862

RESUMO

After germination, plants go through two phases of vegetative development - juvenile and adult - before entering the reproductive phase. These phases have varying characteristics and timing across plant species, making it challenging to determine if different vegetative traits correspond to the same or distinct developmental processes. miR156 has been identified as the primary regulator of vegetative phase change in plants, with the miR156-SPLs (SQUAMOSA Promoter Binding Protein-Likes) module playing a crucial role in regulating age-related agronomic traits in various crops. Such traits include disease resistance, optimal plant breeding, and secondary metabolism regulation. However, it is unknown whether miR156-SPLs contribute to the critical agronomic traits of pepper (Capsicum annuum L.). Thus, this study seeks to identify miR156 and SPLs genes in pepper, analyze their evolutionary links with model plants, and confirm their expression patterns using gene expression assays. The study also examines the relationship between miR156 expression levels in two cultivars of pepper and specific traits associated with the juvenile-to-adult transition. The results indicate that leaf shape and the number of leaf veins are correlated to the timing expression of miR156. Our study represents an important resource for identifying age-dependent agronomic traits in pepper and lays the foundation for future systematic regulation of miR156-SPLs to advance pepper development.


Assuntos
Capsicum , MicroRNAs , Capsicum/genética , Capsicum/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Melhoramento Vegetal , Folhas de Planta/genética , Folhas de Planta/metabolismo , Regiões Promotoras Genéticas , Regulação da Expressão Gênica de Plantas
9.
Phys Rev Lett ; 130(24): 243801, 2023 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-37390435

RESUMO

Owing to the chirality of Weyl nodes characterized by the first Chern number, a Weyl system supports one-way chiral zero modes under a magnetic field, which underlies the celebrated chiral anomaly. As a generalization of Weyl nodes from three-dimensional to five-dimensional physical systems, Yang monopoles are topological singularities carrying nonzero second-order Chern numbers c_{2}=±1. Here, we couple a Yang monopole with an external gauge field using an inhomogeneous Yang monopole metamaterial and experimentally demonstrate the existence of a gapless chiral zero mode, where the judiciously designed metallic helical structures and the corresponding effective antisymmetric bianisotropic terms provide the means for controlling gauge fields in a synthetic five-dimensional space. This zeroth mode is found to originate from the coupling between the second Chern singularity and a generalized 4-form gauge field-the wedge product of the magnetic field with itself. This generalization reveals intrinsic connections between physical systems of different dimensions, while a higher-dimensional system exhibits much richer supersymmetric structures in Landau level degeneracy due to the internal degrees of freedom. Our study offers the possibility of controlling electromagnetic waves by leveraging the concept of higher-order and higher-dimensional topological phenomena.

10.
Nanotechnology ; 34(36)2023 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-37257444

RESUMO

In this study, we present a facile wet chemical method for synthesizing Ni-modified polymeric carbon nitride (g-C3N4) nanosheets. X-ray absorption fine structure spectroscopy reveals the formation of a unique Ni-N structure, resulting from Ni atoms anchoring in cavities of g-C3N4. The Ni anchoring on the surface N sites modifies the electronic structure of g-C3N4, demonstrating remarkable effectiveness even at low anchoring amounts. The as-prepared Ni/g-C3N4catalysts show robust performance for photocatalytic hydrogen evolution under visible light irradiation, attributed to the unique Ni-N interactions. Specifically, the photocatalytic H2production rate of the Ni/CN-45 catalyst reached 8482.14µmol·g-1·h-1with an apparent quantum efficiency of 0.75% under light irradiation at 427 nm. This rate surpasses most of the previously reported g-C3N4based photocatalysts and is nearly 8 times higher than that of the pure g-C3N4catalyst (1116.07µmol·g-1·h-1).


Assuntos
Eletrônica , Hidrogênio , Luz , Polímeros , Espectroscopia por Absorção de Raios X
11.
J Sci Food Agric ; 103(12): 5811-5818, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37092328

RESUMO

BACKGROUND: Potato protein possesses strong potential for application in the food industry due to its outstanding nutritional and functional properties. However, the inevitable industrial processing often brings adverse effects. The use of a polysaccharide and protein complex is a promising way to improve the performance of potato protein. This work aimed to investigate the effects of different physical factors on the potato protein/chitosan (PP/CS) complex system. RESULTS: The addition of NaCl was not conductive to the formation of PP/CS complexes, resulting in significantly decreased peak turbidities from 1.29 to 0.75. The effect of different ions on PP/CS system matched with the Hofmeister series in the following order: Li+ > Control > Na+ > K+ ; SCN- > I- > NO3 - > Br- ≈ Control > Cl- > SO4 2- , among which the salting-in ions (Li+ , Br- , NO3 - , I- and SCN- ) tended to promote the formation of PP/CS complexes. The turbidity increased significantly when the reaction temperature rose to 45 °C and above, and peak turbidity was obtained at lower pH values. The PP/CS system reaction at 45 °C led to the highest whiteness value, and the Maillard reaction could occur when the temperature was above 45 °C. CONCLUSIONS: The results of the present study confirmed that different physical factors led to strong influences on PP/CS complexes, especially when considering the Hofmeister series and the Maillard reaction. These findings could have significant implications for the utilization of potato protein in complex food systems. © 2023 Society of Chemical Industry.


Assuntos
Quitosana , Solanum tuberosum , Quitosana/química , Reação de Maillard , Solanum tuberosum/química , Temperatura , Íons , Cloreto de Sódio
12.
J Colloid Interface Sci ; 630(Pt A): 297-305, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36244102

RESUMO

Solar steam generation (SSG) is a very promising desalination technology. However, new photothermal materials are still to be explored to further reduce the cost, and the device structure is still to be innovated to improve the structural integrality and evaporation performance. In this work, an all-in-one highly-efficient and self-floating jellyfish-like SSG (SFJ-SSG) is developed based on partially carbonized Enteromorpha (EA) aerogel (PCEAA). The carbonized top surface exhibits high solar absorption ability and excellent photothermal effect, while the uncarbonized EA retains the hydrophilicity and high-water transport capability due to the nature of tubular algal plant. Moreover, the heat produced by photothermal effect of the carbonized EA is confined at the top surface due to the thermal insulation of the uncarbonized layer, which is very beneficial for interfacial water evaporation. After optimizing the carbonization time and the height of the SFJ-SSG, a high evaporation rate of 1.87 kg m-2h-1 is obtained under 1.0 sun irradiation, which outcompetes most SSG based on carbonized biomass. The development of SFJ-SSG based on EA not only minimizes the cost of SSG, but also solves the EA pollution, ensuring the broad prospect in practical applications.


Assuntos
Energia Solar , Purificação da Água , Vapor , Luz Solar , Purificação da Água/métodos , Água
13.
Ultrason Sonochem ; 92: 106281, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36586338

RESUMO

Physicochemical properties and microstructure of gluten protein, and the structural characteristics of steamed bread with 30 % potato pulp (SBPP) were investigated by ultrasonic treatments. Results showed that 400 W ultrasonic treatment significantly (P < 0.05) increased the combination of water and substrate in the dough with 30 % potato pulp (DPP). The contents of wet gluten, free sulfhydryl (SH), and disulfide bond (SS) were influenced by ultrasonic treatment. Moreover, UV-visible and fluorescence spectroscopy demonstrated that the conformation of gluten protein was changed by ultrasonic treatment (400 W). Fourier transform infrared (FT-IR) illustrated that the ß-sheet content was significantly (P < 0.05) increased (42 %) after 400 W ultrasonic treatment, and the surface hydrophobicity of gluten protein in SBPP increased from 1225.37 (0 W ultrasonic treatment) to 4588.74 (400 W ultrasonic treatment). Ultrasonic treatment facilitated the generation of a continuous gluten network and stabilized crumb structure, further increased the specific volume and springiness of SBPP to 18.9 % and 6.9 %, respectively. Those findings suggested that ultrasonic treatment would be an efficient method to modify gluten protein and improve the quality of SBPP.


Assuntos
Glutens , Solanum tuberosum , Glutens/química , Solanum tuberosum/química , Pão/análise , Ultrassom , Espectroscopia de Infravermelho com Transformada de Fourier , Vapor
14.
Food Chem ; 407: 135150, 2023 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-36493491

RESUMO

The traditional production of wort with adjunct-introduced was achieved by double mashing procedure, which hindered the utilization of proteins in adjunct and led to a deficiency of nitrogen in wort. In this study, the modification mechanism of the extrusion pretreatment on the structure characterization of rice flour protein was investigated. The decoction mashing procedure was performed to enhance the nitrogen conversion of the extruded rice adjunct. Decreased solubility along with disrupted secondary and tertiary structures of rice protein were observed after extrusion. As a result, the total nitrogen, free amino nitrogen, and free amino acids content of wort with extruded rice adjunct-introduced were improved by 23.28 %, 34.67 %, and 7.33 %, respectively, which could be verified by the electrophoretic patterns of the wort protein. The application of extrusion as a pretreatment of adjuncts can promote the protein availability of adjuncts in the decoction mashing stage.


Assuntos
Oryza , Oryza/química , Proteínas/metabolismo , Solubilidade , Aminoácidos/metabolismo
15.
Comput Math Methods Med ; 2022: 4480349, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36299682

RESUMO

Objective: Thoracolumbar vertebral compression fractures (TVCF) are caused by anterior flexion or vertical downward violence to the spine (Sezer et al. 2021). This study is aimed at investigating the effect of core stability training (CST) on unstable support surfaces in the postoperative rehabilitation of TVCF in the elderly. Methods. Ninety-eight patients with TVCF who underwent surgical treatment in our hospital from July 2021 to April 2022 were selected as study subjects. Then, they were divided into a research group receiving unstable support surface CST and a control group with conventional rehabilitation training according to the random number table method. Before and after the training, the X-ray machine was positioned and the anterior margin and middle height ratio and the posterior convex Cobb angle of the injured vertebrae were observed, and the balance detector was used to detect patients' eye opening and closing trajectory length, Romberg rate, and to perform gait test. Patients' pain, lumbar spine function, and quality of life were subsequently assessed using the Visual Analogue Scale (VAS), Oswestry Dysfunction Index (ODI), Generic Quality of Life Inventory-74 (GQOL-74), and patient satisfaction with rehabilitation was investigated. Results. After rehabilitation training, there was no statistically marked difference in eye-opening trajectory length between both groups (P > 0.05). The research group had higher scores than the control group in all dimensions of the anterior border of the injured vertebra, middle height ratio, and GQOL-74, while the posterior convex Cobb angle, closed-eye trajectory length, Romberg rate, VAS, and ODI were lower than the control group (P < 0.05). The research group also revealed better gait improvement and higher rehabilitation satisfaction than the control group after training (P < 0.05). Conclusion: Unstable support surface CST can effectively improve postoperative vertebral body rehabilitation, balance function, gait, pain conditions, and lumbar spine function in elderly TVCF patients, and enhance their quality of life and rehabilitation satisfaction. This trial is registered with ChiCTR2000014547.


Assuntos
Fraturas por Compressão , Fraturas da Coluna Vertebral , Idoso , Humanos , Estabilidade Central , Fixação Interna de Fraturas/métodos , Fraturas por Compressão/cirurgia , Vértebras Lombares/cirurgia , Dor , Qualidade de Vida , Fraturas da Coluna Vertebral/cirurgia , Vértebras Torácicas/cirurgia , Vértebras Torácicas/lesões , Resultado do Tratamento
16.
J Food Sci ; 87(11): 4967-4976, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36200561

RESUMO

Extrusion has become one of the most popular techniques in food processing, and the process parameters are closely related to product quality. Purslane (Portulaca oleracea L.) can be used in medical and food products as a vegetable and herb. It has limited application in extrusion. The effects of extrusion process variables (screw speed, barrel temperature, and feed moisture) on system variables (specific mechanical energy [SME], die head pressure, and torque) and target variables (water absorption index, water solubility index, iodine blue value, color, pasting properties, and textural properties) of purslane powder compound rice were studied. The results showed that SME was moderately positively correlated with screw speed (r = 0.608, p < 0.05). However, torque was moderately negatively correlated with feed moisture (r = -0.574, p < 0.05), and die head pressure was moderately negatively correlated with barrel temperature (r = -0.635, p < 0.01). The target variables of extrudates were also correlated with the system parameters to varying degrees. These results are helpful to control and predict the texture, pasting properties, and other quality characteristics of extruded products containing purslane powder. PRACTICAL APPLICATION: The results showed that torque and die head pressure were moderately negatively related to barrel temperature, specific mechanical energy was moderately positively related to screw speed, peak viscosity and breakdown viscosity were moderately negatively related to specific mechanical energy, and water absorption index was moderately negatively related to torque and die head pressure. It provides a reference for the research of influencing system parameters and changing product quality by controlling extrusion process parameters. In this study, some possibilities for the application of broken rice and purslane in extrusion processing were proposed.


Assuntos
Oryza , Portulaca , Pós , Água , Folhas de Planta
17.
Opt Express ; 30(20): 35937-35950, 2022 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-36258533

RESUMO

Optical feedback exists in most laser configurations and strongly affects laser performances depending on the feedback strength, length, and phase. In this paper, we investigate the frequency comb behaviour of a semiconductor quantum cascade laser emitting around 4.2 THz with external optical feedback. A periodic evolution of the laser inter-mode beatnote from single-line to multiple-line structures is experimentally observed with a minor change of optical feedback length (phase) on the wavelength scale. The comb stability of the laser with feedback is also measured and compared with the same laser without feedback. Furthermore, our simulations reveal that the dynamical oscillations invoked by optical feedback are responsible for the measured multiple-line beatnotes. It is found that the characteristic feedback period is determined by the half wavelength of the laser, while the comb operation is maintained at most feedback length positions. Therefore, terahertz quantum cascade laser combs are robust against the minor position vibration of the feedback mirror in practice, owing to the much smaller feedback phase change than that of common near-infrared laser diodes.

18.
Nature ; 609(7927): 479-484, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-36104555

RESUMO

Studying strong electron correlations has been an essential driving force for pushing the frontiers of condensed matter physics. In particular, in the vicinity of correlation-driven quantum phase transitions (QPTs), quantum critical fluctuations of multiple degrees of freedom facilitate exotic many-body states and quantum critical behaviours beyond Landau's framework1. Recently, moiré heterostructures of van der Waals materials have been demonstrated as highly tunable quantum platforms for exploring fascinating, strongly correlated quantum physics2-22. Here we report the observation of tunable quantum criticalities in an experimental simulator of the extended Hubbard model with spin-valley isospins arising in chiral-stacked twisted double bilayer graphene (cTDBG). Scaling analysis shows a quantum two-stage criticality manifesting two distinct quantum critical points as the generalized Wigner crystal transits to a Fermi liquid by varying the displacement field, suggesting the emergence of a critical intermediate phase. The quantum two-stage criticality evolves into a quantum pseudo criticality as a high parallel magnetic field is applied. In such a pseudo criticality, we find that the quantum critical scaling is only valid above a critical temperature, indicating a weak first-order QPT therein. Our results demonstrate a highly tunable solid-state simulator with intricate interplay of multiple degrees of freedom for exploring exotic quantum critical states and behaviours.

19.
Phys Rev Lett ; 128(22): 226401, 2022 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-35714264

RESUMO

We study non-Hermitian spatial symmetries-a class of symmetries that have no counterparts in Hermitian systems-and study how normal and exceptional semimetals can be stabilized by these symmetries. Different from internal ones, spatial symmetries act nonlocally in momentum space and enforce global constraints on both band degeneracies and topological quantities at different locations. In deriving general constraints on band degeneracies and topological invariants, we demonstrate that non-Hermitian spatial symmetries are on an equal footing with, but are essentially different from Hermitian ones. First, we discover the nonlocal Hermitian conjugate pair of exceptional or normal band degeneracies that are enforced by non-Hermitian spatial symmetries. Remarkably, we find that these pairs lead to the symmetry-enforced violation of the Fermion doubling theorem in the long-time limit. Second, with the topological constraints, we unravel that a certain exceptional manifold is only compatible with and stabilized by non-Hermitian spatial symmetries but is intrinsically incompatible with Hermitian spatial symmetries. We illustrate these findings using two three-dimensional models of a non-Hermitian Weyl semimetal and an exceptional unconventional Weyl semimetal. Experimental cold-atom realizations of both models are also proposed.

20.
Food Chem ; 390: 133187, 2022 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-35569400

RESUMO

Distiller's grains (DGs) possessed great potential utilization value due to their rich active ingredients. However, its utilization efficiency was limited by the large amount of lignocellulose components and water-insoluble proteins. In this work, single screw extrusion was applied to modify physicochemical properties of DGs. Results indicated that extruded distiller's grains (EDGs) exhibited the lower crude fiber content (26.01%), the higher soluble fiber (9.07%) and the smaller particle size when compared with those of Control, and subsequently achieving the increased bulk density, swelling capacity and water/oil holding capacity. The crude protein in EDGs decreased slightly, while the total amount of acid hydrolyzed amino acids showed a significant increase. Additionally, the looser, coarser and fragmentary microstructure of EDGs were observed. The main macromolecules in EDGs had been modified distinctly based on thermal analysis, crystallinity and functional groups analyses, while the possible schematic diagram was conducted to better understand the modification mechanism.


Assuntos
Aminoácidos , Grão Comestível , Aminoácidos/análise , Ração Animal/análise , Grão Comestível/química , Estruturas Vegetais/química , Proteínas/análise , Água/química
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