Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 174
Filtrar
Más filtros

País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
EMBO J ; 42(4): e111883, 2023 02 15.
Artículo en Inglés | MEDLINE | ID: mdl-36546550

RESUMEN

Proper stamen filament elongation is essential for pollination and plant reproduction. Plant hormones are extensively involved in every stage of stamen development; however, the cellular mechanisms by which phytohormone signals couple with microtubule dynamics to control filament elongation remain unclear. Here, we screened a series of Arabidopsis thaliana mutants showing different microtubule defects and revealed that only those unable to sever microtubules, lue1 and ktn80.1234, displayed differential floral organ elongation with less elongated stamen filaments. Prompted by short stamen filaments and severe decrease in KTN1 and KTN80s expression in qui-2 lacking five BZR1-family transcription factors (BFTFs), we investigated the crosstalk between microtubule severing and brassinosteroid (BR) signaling. The BFTFs transcriptionally activate katanin-encoding genes, and the microtubule-severing frequency was severely reduced in qui-2. Taken together, our findings reveal how BRs can regulate cytoskeletal dynamics to coordinate the proper development of reproductive organs.


Asunto(s)
Brasinoesteroides , Katanina , Microtúbulos , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Brasinoesteroides/metabolismo , Katanina/genética , Katanina/metabolismo , Microtúbulos/metabolismo , Reguladores del Crecimiento de las Plantas/metabolismo
2.
Plant Cell ; 34(10): 4028-4044, 2022 09 27.
Artículo en Inglés | MEDLINE | ID: mdl-35867001

RESUMEN

Ribosome biogenesis is a fundamental and highly orchestrated process that involves hundreds of ribosome biogenesis factors. Despite advances that have been made in yeast, the molecular mechanism of ribosome biogenesis remains largely unknown in plants. We uncovered a WD40 protein, Shrunken and Embryo Defective Kernel 1 (SHREK1), and showed that it plays a crucial role in ribosome biogenesis and kernel development in maize (Zea mays). The shrek1 mutant shows an aborted embryo and underdeveloped endosperm and embryo-lethal in maize. SHREK1 localizes mainly to the nucleolus and accumulates to high levels in the seed. Depleting SHREK1 perturbs pre-rRNA processing and causes imbalanced profiles of mature rRNA and ribosome. The expression pattern of ribosomal-related genes is significantly altered in shrek1. Like its yeast (Saccharomyces cerevisiae) ortholog Periodic tryptophan protein 1 (PWP1), SHREK1 physically interacts with ribosomal protein ZmRPL7a, a transient component of the PWP1-subcomplex involved in pre-rRNA processing in yeast. Additionally, SHREK1 may assist in the A3 cleavage of the pre-rRNA in maize by interacting with the nucleolar protein ZmPOP4, a maize homolog of the yeast RNase mitochondrial RNA-processing complex subunit. Overall, our work demonstrates a vital role of SHREK1 in pre-60S ribosome maturation, and reveals that impaired ribosome function accounts for the embryo lethality in shrek1.


Asunto(s)
Precursores del ARN , Proteínas de Saccharomyces cerevisiae , Proteínas Nucleares/metabolismo , Precursores del ARN/genética , Precursores del ARN/metabolismo , Procesamiento Postranscripcional del ARN/genética , ARN Mitocondrial/metabolismo , ARN Ribosómico/genética , ARN Ribosómico/metabolismo , Ribonucleasas/metabolismo , Proteínas Ribosómicas/genética , Proteínas Ribosómicas/metabolismo , Ribosomas/genética , Ribosomas/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Triptófano/metabolismo , Zea mays/metabolismo
3.
BMC Med ; 22(1): 54, 2024 02 05.
Artículo en Inglés | MEDLINE | ID: mdl-38317131

RESUMEN

BACKGROUND: The appropriateness of hypertension thresholds for triggering action to prevent cardiovascular and renal complications among non-White populations in the UK is subject to question. Our objective was to establish ethnicity-specific systolic blood pressure (SBP) cutoffs for ethnic minority populations and assess the efficacy of these ethnicity-specific cutoffs in predicting adverse outcomes. METHODS: We analyzed data from UK Biobank, which included 444,418 participants from White, South Asian, Black Caribbean, and Black African populations with no history of cardiorenal complications. We fitted Poisson regression models with continuous SBP and ethnic groups, using Whites as the referent category, for the composite outcome of atherosclerotic cardiovascular disease, heart failure, and chronic kidney disease. We determined ethnicity-specific thresholds equivalent to the risks observed in Whites at SBP levels of 120, 130, and 140 mm Hg. We adjusted models for clinical characteristics, sociodemographic factors, and behavioral factors. The performance of ethnicity-specific thresholds for predicting adverse outcomes and associated population-attributable fraction (PAF) was assessed in ethnic minority groups. RESULTS: After a median follow-up of 12.5 years (interquartile range, 11.7-13.2), 32,662 (7.4%) participants had incident composite outcomes. At any given SBP, the predicted incidence rate of the composite outcome was the highest for South Asians, followed by White, Black Caribbean, and Black African. For an equivalent risk of outcomes observed in the White population at an SBP level of 140 mm Hg, the SBP threshold was lower for South Asians (123 mm Hg) and higher for Black Caribbean (156 mm Hg) and Black African (165 mm Hg). Furthermore, hypertension defined by ethnicity-specific thresholds was a stronger predictor and resulted in a larger PAF for composite outcomes in South Asians (21.5% [95% CI, 2.4,36.9] vs. 11.3% [95% CI, 2.6,19.1]) and Black Africans (7.1% [95% CI, 0.2,14.0] vs. 5.7 [95% CI, -16.2,23.5]) compared to hypertension defined by guideline-recommended thresholds. CONCLUSIONS: Guideline-recommended blood pressure thresholds may overestimate risks for the Black population and underestimate risks for South Asians. Using ethnicity-specific SBP thresholds may improve risk estimation and optimize hypertension management toward the goal of eliminating ethnic disparities in cardiorenal complications.


Asunto(s)
Etnicidad , Hipertensión , Humanos , Estudios Prospectivos , Presión Sanguínea , Biobanco del Reino Unido , Bancos de Muestras Biológicas , Grupos Minoritarios , Hipertensión/epidemiología , Factores de Riesgo
4.
New Phytol ; 241(4): 1662-1675, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38058237

RESUMEN

Ribosome biogenesis is a highly dynamic and orchestrated process facilitated by hundreds of ribosomal biogenesis factors and small nucleolar RNAs. While many of the advances are derived from studies in yeast, ribosome biogenesis remains largely unknown in plants despite its importance to plant growth and development. Through characterizing the maize (Zea mays) defective kernel and embryo-lethal mutant dek58, we show that DEK58 encodes an Rrp15p domain-containing protein with 15.3% identity to yeast Rrp15. Over-expression of DEK58 rescues the mutant phenotype. DEK58 is localized in the nucleolus. Ribosome profiling and RNA gel blot analyses show that the absence of DEK58 reduces ribosome assembly and impedes pre-rRNA processing, accompanied by the accumulation of nearly all the pre-rRNA processing intermediates and the production of an aberrant processing product P-25S*. DEK58 interacts with ZmSSF1, a maize homolog of the yeast Ssf1 in the 60S processome. DEK58 and ZmSSF1 interact with ZmCK2α, a putative component of the yeast UTP-C complex involved in the small ribosomal subunit processome. These results demonstrate that DEK58 is essential to seed development in maize. It functions in the early stage of pre-rRNA processing in ribosome biogenesis, possibly through interacting with ZmSSF1 and ZmCK2α in maize.


Asunto(s)
ARN Ribosómico , Zea mays , Zea mays/genética , Zea mays/metabolismo , ARN Ribosómico/genética , ARN Ribosómico/metabolismo , Saccharomyces cerevisiae/metabolismo , Proteínas Ribosómicas/genética , Proteínas Ribosómicas/metabolismo , Precursores del ARN/genética , Precursores del ARN/metabolismo , Ribosomas/metabolismo , Semillas/genética , Semillas/metabolismo , Procesamiento Postranscripcional del ARN/genética
5.
Exp Cell Res ; 423(2): 113471, 2023 02 15.
Artículo en Inglés | MEDLINE | ID: mdl-36642263

RESUMEN

Vasoactive intestinal peptide (VIP), a small neuropeptide composing of 28 amino acids, functions as a neuromodulator with insulinotropic effect on pancreatic ß cells, in which it is of vital importance in regulating the levels of blood glucose. VIP potently agonizes VPAC2 receptor (VPAC2-R). Agonists of VPAC2-R stimulate glucose-dependent insulin secretion. The purpose of this study was to further investigate the possible ion channel mechanisms in VPAC2-R-mediated VIP-potentiated insulin secretion. The results of insulin secretion experiments showed that VIP augmented insulin secretion in a glucose-dependent manner. The insulinotropic effect was mediated by VPAC2-R rather than VPAC1 receptor (VPAC1-R), through the adenylyl cyclase (AC)/protein kinase A (PKA) signalling pathway. The calcium imaging analysis demonstrated that VIP increased intracellular Ca2+ concentration ([Ca2+]i). In addition, in the whole-cell voltage-clamp mode, we found that VIP blocked the voltage-dependent potassium (Kv) channel currents, while this effect was reversed by inhibiting the VPAC2-R, AC or PKA respectively. Taken together, these findings suggest that VIP stimulates insulin secretion by inhibiting the Kv channels, activating the Ca2+ channels, and increasing [Ca2+]i through the VPAC2-R and AC/PKA signalling pathway. These findings provide theoretical basis for the research of VPAC2-R as a novel therapeutic target.


Asunto(s)
Células Secretoras de Insulina , Péptido Intestinal Vasoactivo , Ratas , Animales , Péptido Intestinal Vasoactivo/farmacología , Receptores de Tipo II del Péptido Intestinal Vasoactivo/agonistas , Receptores de Tipo II del Péptido Intestinal Vasoactivo/metabolismo , Secreción de Insulina , Células Secretoras de Insulina/metabolismo , Canales Iónicos/metabolismo , Glucosa/farmacología
6.
Environ Res ; 249: 118384, 2024 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-38307180

RESUMEN

A comprehensive monitoring and risk assessment of arsenic (As) pollution concerning surface water and sediment is performed in the Jie River basin, where gold smelting enterprises are concentrated. The study area is divide into six regions, labeled as A, B, C, D, E, and F, from sewage outlets to downstream. Results shows that with far away from the sewage outlets, the total As concentrations in water and sediment gradually decrease from regions A to F. However, in region F, the concentration of bioavailable As significantly increases in the sediment due to the higher pH, leading to the transformation of As(V) into more mobile As(III). In sediment, Paracladius sp. exhibits strong resistance to As pollution in sediment, which can potentially elevate the risk of disease transmission. In water bodies, diatoms and euglena are the main phytoplankton in the Jie River while toxic cyanobacteria exhibits lower resistance to As pollution. Overall, measures should be taken to ecologically remediate the sediment in downstream while implementing appropriate isolation methods to prevent the spread of highly contaminated sediments from regions near sewage outlets.


Asunto(s)
Arsénico , Monitoreo del Ambiente , Sedimentos Geológicos , Oro , Ríos , Contaminantes Químicos del Agua , Sedimentos Geológicos/química , Sedimentos Geológicos/análisis , Arsénico/análisis , Ríos/química , Contaminantes Químicos del Agua/análisis , China , Metalurgia , Proyectos Piloto
7.
Environ Res ; 247: 118255, 2024 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-38266890

RESUMEN

Lewis acids of solid catalysts have been featured for a pivotal role in promoting various reactions. Regarding the oxidation protocol to remove formaldehyde, the inherent drawback of the best-studied MnO2 materials in acidic sites has eventually caused deficiency of active hydroxyls to sustain low-temperature activity. Herein, the cryptomelane-type MnO2 was targeted and it was tuned via incorporation of Zr metal, exhibiting great advances in not only the complete HCHO-to-CO2 degradation but also cycling performance. Zr species were existent in doping state in the MnO2 lattice, rendering lower crystallinity and breaking the regular growth of MnO2 crystallites, which thereby tripled surface area and created larger volume of smaller mesopores. Meantime, the local electronic properties of Mn atoms were also changed by Zr doping, i.e., more low-valence Mn species were formed due to the electron transfer from Zr to Mn. The results of infrared studies demonstrate the higher possession of Lewis acid sites on ZrMn, and this high degree of electrophilic agents favored the production of hydroxyl species. Furthermore, the reactivity of surface hydroxyls, as investigated by CO temperature programmed reduction and temperature programmed desorption of adsorbed O2, was obviously improved as well after Zr modification. It is speculated jointly with the characterizations of the post-reaction catalysts that the accelerated production of active hydroxyls helped rapidly convert formaldehyde into key intermediate-formate, which was then degraded into CO2, avoiding the side reaction path with undesired intermediate-hydrocarbonate-over the pristine MnO2, where active sites were blocked and formaldehyde oxidation was inhibited. Additionally, Zr decoration could stabilize Lewis acidity to be more resistant to heat degeneration, and this merit brought about advantageous thermal recyclability for cycled application.


Asunto(s)
Ácidos de Lewis , Óxidos , Óxidos/química , Compuestos de Manganeso/química , Dióxido de Carbono , Formaldehído/química , Catálisis
8.
Chem Biodivers ; 21(4): e202302053, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38270380

RESUMEN

Five compounds (1-5), one long-chain fatty acid (1), two thiophenes (2 and 3), one alkaloid (4), and one phenyl ester (5), were isolated from the aerial part of Echinops davuricus. The structures of the products were established by performing detailed nuclear magnetic resonance (NMR) analysis, and the structure of compound 1 was determined via high-resolution electrospray ionization mass spectrometry (HRESIMS) and NMR. Compounds 1, 4, and 5 were isolated from Echinops davuricus for the first time. Based on network pharmacology methods, AKR1B10 was selected as a key anticancer target. Compounds 1 and 5 exhibited significant AKR1B10 inhibitory activities, with IC50 values of 156.0±1.00 and 146.2±1.50 nM, respectively, with epalrestat used as the positive control (81.09±0.61 nM). Additionally, the interactions between the active compounds and AKR1B10 were evaluated via molecular docking. Ultimately, the GO and KEGG enrichment analysis indicated that the key signaling pathways associated with the active compounds may be related to the PI3K-Akt, MAPK, apoptotic, cellular senescence, and TNF signaling pathways and the human diseases corresponding to the targets are cancer. Our study reveals for the first time the anticancer properties of Echinops davuricus and provides a comprehensive understanding of its application in traditional medicine.


Asunto(s)
Medicamentos Herbarios Chinos , Fosfatidilinositol 3-Quinasas , Humanos , Simulación del Acoplamiento Molecular , Tenrecidae , Ésteres , Ácidos Grasos , Aldo-Ceto Reductasas
9.
Nano Lett ; 23(4): 1211-1218, 2023 Feb 22.
Artículo en Inglés | MEDLINE | ID: mdl-36748951

RESUMEN

Interfacial atomic configuration and its evolution play critical roles in the structural stability and functionality of mixed zero-dimensional (0D) metal nanoparticles (NPs) and two-dimensional (2D) semiconductors. In situ observation of the interface evolution at atomic resolution is a vital method. Herein, the directional migration and structural evolution of Au NPs on anisotropic ReS2 were investigated in situ by aberration-corrected transmission electron microscopy. Statistically, the migration of Au NPs with diameters below 3 nm on ReS2 takes priority with greater probability along the b-axis direction. Density functional theory calculations suggest that the lower diffusion energy barrier enables the directional migration. The coalescence kinetics of Au NPs is quantitatively described by the relation of neck radius (r) and time (t), expressed as r2=Kt. Our work provides an atomic-resolved dynamic analysis method to study the interfacial structural evolution of metal/2D materials, which is essential to the study of the stability of nanodevices based on mixed-dimensional nanomaterials.

10.
J Sci Food Agric ; 104(6): 3697-3704, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38160247

RESUMEN

INTRODUCTION: One of the main allergens in soybeans is glycinin, which seriously impacts the normal lives of allergic people. Previous studies have confirmed that thermal processing and thermal processing combined with ultrahigh-pressure processing could significantly reduce the antigenicity of glycinin. The dominant antigen region of acidic peptide chain A2 of G2 subunit was located by phage display experiment. METHODS: In this paper, overlapping peptides and alanine substitution techniques were used to explore the key amino acids that significantly affect the antigenicity of A2 peptide chain. The purity of peptide 1, peptide 2 and peptide 3 was identified by mass spectrometry and high-performance liquid chromatography, and the results showed that the purity of the synthesized overlapping peptide was more than 90%. SDS-PAGE showed that the peptide was successfully coupled with bovine serum albumin. The antigenicity of the coupling peptide was tested by ELISA and Dot-Blot, and the allergenicity was detected by reacting with the serum of patients with soybean globulin allergy. CONCLUSION: The results showed that peptide 3 has stronger antigenicity and sensitization. Alanine substitution technology allowed one to perform site-directed mutagenesis on peptide 3. Dot-Blot and ELISA tests showed that D259, E260, E261, Q263 and C266 may be the key amino acids that significantly affect the antigenicity of peptide 3. The research presented is of great significance for correctly guiding the production of safe food and preventing the occurrence of food allergic diseases. © 2023 Society of Chemical Industry.


Asunto(s)
Globulinas , Proteínas de Soja , Humanos , Epítopos/química , Proteínas de Soja/química , Glycine max , Globulinas/química , Alérgenos , Péptidos , Alanina , Aminoácidos , Inmunoglobulina E
11.
Rev Esp Enferm Dig ; 116(2): 68-76, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37706492

RESUMEN

BACKGROUND: The association between sarcopenia and treatment outcomes in inflammatory bowel disease (IBD) is currently a subject of controversy. METHODS: A systematic search was performed of PubMed, Embase, Web of Science, and the Cochrane Library for studies published until April 2023. The quality assessment of each included study was performed using the Newcastle-Ottawa Scale. RESULTS: Seventeen studies were included with 2,895 IBD patients. Sarcopenia exhibited an increased risk of treatment failure (OR=2.00, 95% CI: 1.43-2.79) and notably increased the need for surgery (OR=1.54,95%CI:1.06-2.23) as opposed to a pharmacologic treatment plan change (OR=1.19, 95% CI:0.71-2.01) among IBD patients. However, no significant association was found between sarcopenia and treatment failure in corticosteroid (OR=1.21, 95% CI: 0.55-2.64) or biologic agent (OR=1.65, 95% CI: 0.93-2.92) cohorts. Sarcopenia was also linked to elevated treatment failure risks in patients with Crohn's disease (OR=1.82, 95% CI: 1.15-2.90) and those diagnosed with ulcerative colitis (OR=2.55, 95% CI: 1.05-6.21), spanning both Asian (OR=1.88, 95% CI: 1.29-2.74) and non-Asian regions (OR=2.17, 95% CI: 1.48-3.18). CONCLUSIONS: Sarcopenia was considered a novel marker for use in clinical practice to predict treatment failure, specifically, the need for surgery in IBD patients. This distinct cohort necessitates clinical attention and tailored care strategies.


Asunto(s)
Colitis Ulcerosa , Enfermedad de Crohn , Enfermedades Inflamatorias del Intestino , Sarcopenia , Humanos , Sarcopenia/etiología , Sarcopenia/terapia , Sarcopenia/diagnóstico , Enfermedades Inflamatorias del Intestino/complicaciones , Enfermedades Inflamatorias del Intestino/terapia , Enfermedades Inflamatorias del Intestino/diagnóstico , Colitis Ulcerosa/terapia , Colitis Ulcerosa/tratamiento farmacológico , Enfermedad de Crohn/tratamiento farmacológico , Insuficiencia del Tratamiento
12.
Small ; 19(35): e2301469, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37098645

RESUMEN

Single-atom catalysts (SACs) exhibit remarkable potential for electrochemical reduction of CO2 to value-added products. However, the commonly pursued methods for preparing SACs are hard to scale up, and sometimes, lack general applicability because of expensive raw materials and complex synthetic procedures. In addition, the fine tuning of coordination environment of SACs remains challenging due to their structural vulnerability. Herein, a simple and universal strategy is developed to fabricate Ni SACs with different nitrogen coordination numbers through one-step pyrolysis of melamine, Ni(NO3 )∙6H2 O, and polyvinylpyrrolidone at different temperatures. Experimental measurements and theoretical calculations reveal that the low-coordinate Ni SACs exhibit outstanding CO2 reduction performance and stability, achieving a Faradic efficiency (FECO ) of 98.5% at -0.76 V with CO current density of 24.6 mA cm-2 , and maintaining FECO of over 91.0% at all applied potential windows from -0.56 to -1.16 V, benefiting from its coordinatively unsaturated structure to afford high catalytic activity and low barrier for the formation of *COOH intermediate. No significant performance degradation is observed over 50 h of continuous operation. Additionally, several other metallic single-atom catalysts are successfully prepared by this synthetic method, demonstrating the universality of this strategy.

13.
Mol Phylogenet Evol ; 180: 107698, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36587885

RESUMEN

The water boatmen of Corixoidea, a group of aquatic bugs with more than 600 extant species, is one of the largest superfamilies of Nepomorpha. Contrary to the other nepomorphan lineages, the Corixoidea are most diverse in the Laurasian remnant Holarctic region. To explicitly test whether the present-day Holarctic distribution of diverse corixids is associated with the arising of the Laurasian landmass that was separated from Gondwana, we investigated the phylogeny, divergence times and historical biogeography of Corixoidea based on morphological and molecular characters sampled from 122 taxa representing all families, subfamilies, tribes and approximately 54 % of the genera. Our results were largely congruent with the phylogenetic relationships within the established nepomorphan phylogenetic context. The fossil calibrated chronogram, diversification analysis and ancestral ranges reconstruction indicated that Corixoidea began to diversify in Gondwana in the late Triassic approximately at 224 Ma and the arising of the most diverse subfamily Corixinae in Corixidae in the Holarctic region was largely congruent with the time of separation of Laurasia from Gondwana. The large-scale expansion of the temperate and cold zones on the northward-moving Laurasian landmass after the breakup of the Pangea provided new aquatic niches and ecological opportunities for promoting rapid diversification for the Holarctic corixid lineage.


Asunto(s)
Heterópteros , Humanos , Animales , Filogenia , Heterópteros/genética , Ambiente , Fósiles
14.
Opt Express ; 31(21): 35086-35099, 2023 Oct 09.
Artículo en Inglés | MEDLINE | ID: mdl-37859248

RESUMEN

Metasurfaces have shown extraordinary capability in individually manipulating various electromagnetic (EM) properties, including polarization, phase, and amplitude. However, it is still a challenge to manipulate these EM properties in one metasurface simultaneously. In this paper, a programmable multifunctional metasurface (PMFMS) is demonstrated with polarization, phase, and amplitude manipulation abilities. By controlling tunable coding states and changing the direction of incident waves, the PMFMS can operate as a transmission cross-polarization converter, spatial wave manipulator, and low-RCS radome. Besides, the PMFMS possesses an ultra-wideband property, which can operate from 6.5 to 10.2 GHz with 44.3% relative bandwidth. More importantly, multiple functionalities can also be achieved in reflection operating mode by reassembling the PMFMS. As a proof of concept, the PMFMS is fabricated and experimentally verified. Measured results are in good agreement with simulated results. Benefiting from multifunctional EM manipulations in an ultra-wideband, such a design can be applied in wireless communication systems, radar detection, and EM stealth platform.

15.
Opt Express ; 31(10): 16471-16483, 2023 May 08.
Artículo en Inglés | MEDLINE | ID: mdl-37157725

RESUMEN

Electronically reconfigurable transmitarray (ERTA) combines the advantages of optic theory and coding metasurface mechanism with the characteristic of low-loss spatial feed and real-time beam manipulation. Designing a dual-band ERTA is challenging due to multiple factors, including large mutual coupling generated by dual-band operation and separate phase control in each band. In this paper, a dual-band ERTA is demonstrated with the capability of fully independent beam manipulation in two divided bands. This dual-band ERTA is constructed by two kinds of orthogonally polarized reconfigurable elements which share the aperture in an interleaved way. The low coupling is achieved by utilizing polarization isolation and a backed cavity connected to the ground. To separately control the 1-bit phase in each band, a hierarchical bias method is elaborately presented. As proof of concept, a dual-band ERTA prototype composed of 15 × 15 upper-band elements and 16 × 16 lower-band elements is designed, fabricated, and measured. Experimental results verify that fully independent beam manipulation with orthogonal polarization is implemented in 8.2-8.8 GHz and 11.1-11.4 GHz. The proposed dual-band ERTA may be a suitable candidate for space-based synthetic aperture radar imaging.

16.
Rapid Commun Mass Spectrom ; 37(14): e9529, 2023 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-37125446

RESUMEN

RATIONALE: Thymoma is a rare malignant tumor but it is the most common primary tumor of the anterior mediastinum. The current imaging methods for thymoma screening suffer from false positive rate problems, and thymoma pathogenesis remains elusive. Study of thymoma metabolic characteristics could provide clues for improving the diagnosis and understanding the pathogenesis of thymoma. METHODS: Metabolic profiling of plasma from thymoma and thymic hyperplasia patients was performed using ultrahigh-performance liquid chromatography combined with high-resolution mass spectrometry in both positive and negative ionization modes. After pre- and post-processing, the dataset was divided into three age groups and statistical analysis was performed to select differential metabolites of thymoma. For feature identification, experimental tandem mass spectra were matched to those of databases and available chemical standards, and also manually annotated with plausible chemical structures to ensure high identification confidence. RESULTS: A total of 47 differential metabolites were identified in thymoma. Significantly higher levels of histidine, sphinganine 1-phosphate, lactic acid dimer, phenylacetylglutamine, LPC (18:3) and LPC (16:1), and significantly lower levels of phenylalanine, indole-3-propionic acid (IPA), hippuric acid and mesobilirubinogen were associated with thymoma. Tryptophan level in thymoma-associated myasthenia gravis (TAMG) was significantly lower than that of the MG(-) group. IPA and hippuric acid abundances exhibited increasing trends from indolent to aggressive thymoma. CONCLUSIONS: Our study revealed aberrant aromatic amino acid metabolism and fatty acid oxidation might be associated with thymoma. The identified unique metabolic characteristics of thymoma may provide valuable information for study of the molecular mechanism of thymoma pathogenesis, and improvement of diagnosis and discovery of new therapeutic strategies for thymoma.


Asunto(s)
Timoma , Hiperplasia del Timo , Neoplasias del Timo , Humanos , Timoma/complicaciones , Timoma/diagnóstico , Timoma/patología , Hiperplasia del Timo/complicaciones , Hiperplasia del Timo/patología , Neoplasias del Timo/complicaciones , Neoplasias del Timo/diagnóstico , Neoplasias del Timo/patología , Metabolómica , Espectrometría de Masas , Cromatografía Liquida
17.
Environ Res ; 217: 114938, 2023 01 15.
Artículo en Inglés | MEDLINE | ID: mdl-36436556

RESUMEN

To obtain a versatile formaldehyde oxidation material, simultaneously increasing the oxidative ability, recyclability and deactivation repellence (e.g., enduring the interference from moisture and aromatic compound omnipresent in indoor air) is of great significance. Herein, the above properties of α-MnO2 were synchronously updated via one step treatment in oxalic acid (H2C2O4), and an in-depth understanding of the surface properties-performance relationship was provided by systematic characterizations and designed experiments. Compared with the pristine sample, XPS, ESR, O2-TPD, CO-TPR and pyridine-IR reveal that H2C2O4 created substantial Mn3+ species on surface, exposing a higher coverage of oxygen vacancies that actively participated in the dissociative activation of gas-phase O2 into reactive chemically adsorbed oxygen (OC), and the abundant Lewis acid sites further enabled the effective O2 activation process. The large amount of oxygen OC promoted the HCHO-to-CO2 conversion and inhibited the accumulation of formate that required a high temperature of 170 °C to be eliminated, thus conspicuously improving the α-MnO2's thermal recovery. The combined H2O-TPD, H2O-preadsorbed CO-TPR, C6H6-TPD and C6H6-preadsorbed CO-TPR investigations shed light on the H2C2O4-induced water and benzene resistance. The notably weakened water and benzene binding strength with the H2C2O4-modified surface together with the unrestrained oxygen OC accounted for the outstanding anti-deactivation performance.


Asunto(s)
Óxidos , Agua , Óxidos/química , Ácido Oxálico , Temperatura , Compuestos de Manganeso/química , Benceno , Oxígeno/química , Catálisis , Formaldehído/química , Estrés Oxidativo
18.
Nano Lett ; 22(7): 3125-3132, 2022 Apr 13.
Artículo en Inglés | MEDLINE | ID: mdl-35353537

RESUMEN

We report the experimental realization of a two-dimensional (2D) weak topological insulator (WTI) in spinless Su-Schrieffer-Heeger circuits with parity-time and chiral symmetries. Strong and weak Z2 topological indexes are adopted to explain the experimental findings that a Dirac semimetal (DSM) phase and four WTI phases emerge in turn when we modulate the centrosymmetric circuit deformations. In the DSM phase, it is found that the Dirac cone is highly anisotropic and that it is not pinned to any high-symmetry points but can widely move within the Brillouin zone, which eventually leads to the phase transition between WTIs. In addition, we observe a pair of flat-band domain wall states by designing spatially inhomogeneous node connections. Our work provides the first experimental evidence for 2D WTIs, which significantly advances our understanding of the strong and weak nature of topological insulators, the robustness of flat bands, and the itinerant and anisotropic features of Dirac cones.

19.
Int J Mol Sci ; 24(11)2023 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-37298136

RESUMEN

The PEBP gene family is crucial for the growth and development of plants, the transition between vegetative and reproductive growth, the response to light, the production of florigen, and the reaction to several abiotic stressors. The PEBP gene family has been found in numerous species, but the SLPEBP gene family has not yet received a thorough bioinformatics investigation, and the members of this gene family are currently unknown. In this study, bioinformatics was used to identify 12 members of the SLPEBP gene family in tomato and localize them on the chromosomes. The physicochemical characteristics of the proteins encoded by members of the SLPEBP gene family were also examined, along with their intraspecific collinearity, gene structure, conserved motifs, and cis-acting elements. In parallel, a phylogenetic tree was built and the collinear relationships of the PEBP gene family among tomato, potato, pepper, and Arabidopsis were examined. The expression of 12 genes in different tissues and organs of tomato was analyzed using transcriptomic data. It was also hypothesized that SLPEBP3, SLPEBP5, SLPEBP6, SLPEBP8, SLPEBP9, and SLPEBP10 might be related to tomato flowering and that SLPEBP2, SLPEBP3, SLPEBP7, and SLPEBP11 might be related to ovary development based on the tissue-specific expression analysis of SLPEBP gene family members at five different stages during flower bud formation to fruit set. This article's goal is to offer suggestions and research directions for further study of tomato PEBP gene family members.


Asunto(s)
Solanum lycopersicum , Solanum lycopersicum/genética , Filogenia , Genoma de Planta , Familia de Multigenes , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
20.
Int J Mol Sci ; 24(6)2023 Mar 17.
Artículo en Inglés | MEDLINE | ID: mdl-36982833

RESUMEN

The cysteine-rich polycomb-like protein (CPP) gene family is a class of transcription factors containing conserved cysteine-rich CRC structural domains that is involved in the regulation of plant growth and stress tolerance to adversity. Relative to other gene families, the CPP gene family has not received sufficient attention. In this study, six SlCPPs were identified for the first time using the most recent genome-wide identification data of tomato. Subsequently, a phylogenetic analysis classified SlCPPs into four subfamilies. The analysis of cis-acting elements in the promoter indicates that SlCPPs are involved in plant growth and development and also stress response. We present for the first time the prediction of the tertiary structure of these SlCPPs proteins using the AlphaFold2 artificial intelligence system developed by the DeepMind team. Transcriptome data analysis showed that SlCPPs were differentially expressed in different tissues. Gene expression profiling showed that all SlCPPs except SlCPP5 were up-regulated under drought stress; SlCPP2, SlCPP3 and SlCPP4 were up-regulated under cold stress; SlCPP2 and SlCPP5 were up-regulated under salt stress; all SlCPPs were up-regulated under inoculation with Cladosporium fulvum; and SlCPP1, SlCPP3, and SlCPP4 were up-regulated under inoculation with Stemphylium lycopersici. We performed a virus-induced gene silencing experiment on SlCPP3, and the results indicated that SlCPP3 was involved in the response to drought stress. Finally, we predicted the interaction network of the key gene SlCPP3, and there was an interaction relationship between SlCPP3 and 10 genes, such as RBR1 and MSI1. The positive outcome showed that SlCPPs responded to environmental stress. This study provides a theoretical and empirical basis for the response mechanisms of tomato in abiotic stresses.


Asunto(s)
Solanum lycopersicum , Solanum lycopersicum/genética , Cisteína/metabolismo , Filogenia , Inteligencia Artificial , Factores de Transcripción/metabolismo , Perfilación de la Expresión Génica , Estrés Fisiológico/genética , Proteínas de Plantas/metabolismo , Regulación de la Expresión Génica de las Plantas , Familia de Multigenes
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA