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1.
Immunity ; 55(4): 623-638.e5, 2022 04 12.
Artículo en Inglés | MEDLINE | ID: mdl-35385697

RESUMEN

The epithelium is an integral component of mucosal barrier and host immunity. Following helminth infection, the intestinal epithelial cells secrete "alarmin" cytokines, such as interleukin-25 (IL-25) and IL-33, to initiate the type 2 immune responses for helminth expulsion and tolerance. However, it is unknown how helminth infection and the resulting cytokine milieu drive epithelial remodeling and orchestrate alarmin secretion. Here, we report that epithelial O-linked N-Acetylglucosamine (O-GlcNAc) protein modification was induced upon helminth infections. By modifying and activating the transcription factor STAT6, O-GlcNAc transferase promoted the transcription of lineage-defining Pou2f3 in tuft cell differentiation and IL-25 production. Meanwhile, STAT6 O-GlcNAcylation activated the expression of Gsdmc family genes. The membrane pore formed by GSDMC facilitated the unconventional secretion of IL-33. GSDMC-mediated IL-33 secretion was indispensable for effective anti-helminth immunity and contributed to induced intestinal inflammation. Protein O-GlcNAcylation can be harnessed for future treatment of type 2 inflammation-associated human diseases.


Asunto(s)
Alarminas , Mucosa Intestinal , Acilación , Alarminas/inmunología , Antihelmínticos/inmunología , Biomarcadores de Tumor , Citocinas , Proteínas de Unión al ADN , Helmintiasis/inmunología , Humanos , Hiperplasia , Inflamación , Interleucina-33 , Mucosa Intestinal/inmunología , Mebendazol , N-Acetilglucosaminiltransferasas/inmunología , Proteínas Citotóxicas Formadoras de Poros , Factor de Transcripción STAT6/inmunología
2.
Nature ; 595(7868): 521-525, 2021 07.
Artículo en Inglés | MEDLINE | ID: mdl-34290425

RESUMEN

Whereas ferromagnets have been known and used for millennia, antiferromagnets were only discovered in the 1930s1. At large scale, because of the absence of global magnetization, antiferromagnets may seem to behave like any non-magnetic material. At the microscopic level, however, the opposite alignment of spins forms a rich internal structure. In topological antiferromagnets, this internal structure leads to the possibility that the property known as the Berry phase can acquire distinct spatial textures2,3. Here we study this possibility in an antiferromagnetic axion insulator-even-layered, two-dimensional MnBi2Te4-in which spatial degrees of freedom correspond to different layers. We observe a type of Hall effect-the layer Hall effect-in which electrons from the top and bottom layers spontaneously deflect in opposite directions. Specifically, under zero electric field, even-layered MnBi2Te4 shows no anomalous Hall effect. However, applying an electric field leads to the emergence of a large, layer-polarized anomalous Hall effect of about 0.5e2/h (where e is the electron charge and h is Planck's constant). This layer Hall effect uncovers an unusual layer-locked Berry curvature, which serves to characterize the axion insulator state. Moreover, we find that the layer-locked Berry curvature can be manipulated by the axion field formed from the dot product of the electric and magnetic field vectors. Our results offer new pathways to detect and manipulate the internal spatial structure of fully compensated topological antiferromagnets4-9. The layer-locked Berry curvature represents a first step towards spatial engineering of the Berry phase through effects such as layer-specific moiré potential.

3.
Proc Natl Acad Sci U S A ; 121(4): e2317452121, 2024 Jan 23.
Artículo en Inglés | MEDLINE | ID: mdl-38236729

RESUMEN

Bacterial flagella and type IV pili (TFP) are surface appendages that enable motility and mechanosensing through distinct mechanisms. These structures were previously thought to have no components in common. Here, we report that TFP and some flagella share proteins PilO, PilN, and PilM, which we identified as part of the Helicobacter pylori flagellar motor. H. pylori mutants lacking PilO or PilN migrated better than wild type in semisolid agar because they continued swimming rather than aggregated into microcolonies, mimicking the TFP-regulated surface response. Like their TFP homologs, flagellar PilO/PilN heterodimers formed a peripheral cage that encircled the flagellar motor. These results indicate that PilO and PilN act similarly in flagella and TFP by differentially regulating motility and microcolony formation when bacteria encounter surfaces.


Asunto(s)
Proteínas Bacterianas , Fimbrias Bacterianas , Proteínas Bacterianas/metabolismo , Fimbrias Bacterianas/genética , Fimbrias Bacterianas/metabolismo , Bacterias , Flagelos/fisiología
4.
Am J Hum Genet ; 110(4): 606-624, 2023 04 06.
Artículo en Inglés | MEDLINE | ID: mdl-36868238

RESUMEN

Epigenetic reprogramming plays a critical role in chondrocyte senescence during osteoarthritis (OA) pathology, but the underlying molecular mechanisms remain to be elucidated. Here, using large-scale individual datasets and genetically engineered (Col2a1-CreERT2;Eldrflox/flox and Col2a1-CreERT2;ROSA26-LSL-Eldr+/+ knockin) mouse models, we show that a novel transcript of long noncoding RNA ELDR is essential for the development of chondrocyte senescence. ELDR is highly expressed in chondrocytes and cartilage tissues of OA. Mechanistically, exon 4 of ELDR physically mediates a complex consisting of hnRNPL and KAT6A to regulate histone modifications of the promoter region of IHH, thereby activating hedgehog signaling and promoting chondrocyte senescence. Therapeutically, GapmeR-mediated silencing of ELDR in the OA model substantially attenuates chondrocyte senescence and cartilage degradation. Clinically, ELDR knockdown in cartilage explants from OA-affected individuals decreased the expression of senescence markers and catabolic mediators. Taken together, these findings uncover an lncRNA-dependent epigenetic driver in chondrocyte senescence, highlighting that ELDR could be a promising therapeutic avenue for OA.


Asunto(s)
Cartílago Articular , Osteoartritis , ARN Largo no Codificante , Ratones , Animales , Condrocitos/metabolismo , Condrocitos/patología , ARN Largo no Codificante/genética , ARN Largo no Codificante/metabolismo , Cromatina/metabolismo , Cartílago Articular/metabolismo , Cartílago Articular/patología , Proteínas Hedgehog/metabolismo , Osteoartritis/genética , Osteoartritis/metabolismo , Osteoartritis/patología
6.
PLoS Genet ; 19(2): e1010640, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36802400

RESUMEN

The molecular mechanism of tumor metastasis, especially how metastatic tumor cells colonize in a distant site, remains poorly understood. Here we reported that ARHGAP15, a Rho GTPase activating protein, enhanced gastric cancer (GC) metastatic colonization, which was quite different from its reported role as a tumor suppressor gene in other cancers. It was upregulated in metastatic lymph nodes and significantly associated with a poor prognosis. Ectopic expression of ARHGAP15 promoted metastatic colonization of gastric cancer cells in murine lungs and lymph nodes in vivo or protected cells from oxidative-related death in vitro. However, genetic downregulation of ARHGAP15 had the opposite effect. Mechanistically, ARHGAP15 inactivated RAC1 and then decreased intracellular accumulation of reactive oxygen species (ROS), thus enhancing the antioxidant capacity of colonizing tumor cells under oxidative stress. This phenotype could be phenocopied by inhibition of RAC1 or rescued by the introduction of constitutively active RAC1 into cells. Taken together, these findings suggested a novel role of ARHGAP15 in promoting gastric cancer metastasis by quenching ROS through inhibiting RAC1 and its potential value for prognosis estimation and targeted therapy.


Asunto(s)
Neoplasias Gástricas , Ratones , Animales , Especies Reactivas de Oxígeno/metabolismo , Neoplasias Gástricas/genética , Regulación hacia Abajo , Estrés Oxidativo , Proteína de Unión al GTP rac1/genética , Línea Celular Tumoral
7.
Semin Cancer Biol ; 95: 52-74, 2023 10.
Artículo en Inglés | MEDLINE | ID: mdl-37473825

RESUMEN

Head and neck tumors (HNTs) constitute a multifaceted ensemble of pathologies that primarily involve regions such as the oral cavity, pharynx, and nasal cavity. The intricate anatomical structure of these regions poses considerable challenges to efficacious treatment strategies. Despite the availability of myriad treatment modalities, the overall therapeutic efficacy for HNTs continues to remain subdued. In recent years, the deployment of artificial intelligence (AI) in healthcare practices has garnered noteworthy attention. AI modalities, inclusive of machine learning (ML), neural networks (NNs), and deep learning (DL), when amalgamated into the holistic management of HNTs, promise to augment the precision, safety, and efficacy of treatment regimens. The integration of AI within HNT management is intricately intertwined with domains such as medical imaging, bioinformatics, and medical robotics. This article intends to scrutinize the cutting-edge advancements and prospective applications of AI in the realm of HNTs, elucidating AI's indispensable role in prevention, diagnosis, treatment, prognostication, research, and inter-sectoral integration. The overarching objective is to stimulate scholarly discourse and invigorate insights among medical practitioners and researchers to propel further exploration, thereby facilitating superior therapeutic alternatives for patients.


Asunto(s)
Inteligencia Artificial , Neoplasias de Cabeza y Cuello , Humanos , Aprendizaje Automático , Redes Neurales de la Computación , Neoplasias de Cabeza y Cuello/diagnóstico , Neoplasias de Cabeza y Cuello/terapia , Diagnóstico por Imagen/métodos
8.
J Biol Chem ; 299(12): 105481, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-38041932

RESUMEN

Singlet oxygen (1O2) has a very short half-life of 10-5 s; however, it is a strong oxidant that causes growth arrest and necrotic lesions on plants. Its signaling pathway remains largely unknown. The Arabidopsis flu (fluorescent) mutant accumulates a high level of 1O2 and shows drastic changes in nuclear gene expression. Only two plastid proteins, EX1 (executer 1) and EX2 (executer 2), have been identified in the singlet oxygen signaling. Here, we found that the transcription factor abscisic acid insensitive 4 (ABI4) binds the promoters of genes responsive to 1O2-signals. Inactivation of the ABI4 protein in the flu/abi4 double mutant was sufficient to compromise the changes of almost all 1O2-responsive-genes and rescued the lethal phenotype of flu grown under light/dark cycles, similar to the flu/ex1/ex2 triple mutant. In addition to cell death, we reported for the first time that 1O2 also induces cell wall thickening and stomatal development defect. Contrastingly, no apparent growth arrest was observed for the flu mutant under normal light/dim light cycles, but the cell wall thickening (doubled) and stomatal density reduction (by two-thirds) still occurred. These results offer a new idea for breeding stress tolerant plants.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Ácido Abscísico/metabolismo , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Pared Celular/metabolismo , Regulación de la Expresión Génica de las Plantas , Luz , Oxígeno Singlete/metabolismo , Transcriptoma , Estomas de Plantas/metabolismo
9.
BMC Genomics ; 25(1): 612, 2024 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-38890564

RESUMEN

BACKGROUND: Salt sensitivity of blood pressure (SSBP) is an intermediate phenotype of hypertension and is a predictor of long-term cardiovascular events and death. However, the genetic structures of SSBP are uncertain, and it is difficult to precisely diagnose SSBP in population. So, we aimed to identify genes related to susceptibility to the SSBP, construct a risk evaluation model, and explore the potential functions of these genes. METHODS AND RESULTS: A genome-wide association study of the systemic epidemiology of salt sensitivity (EpiSS) cohort was performed to obtain summary statistics for SSBP. Then, we conducted a transcriptome-wide association study (TWAS) of 12 tissues using FUSION software to predict the genes associated with SSBP and verified the genes with an mRNA microarray. The potential roles of the genes were explored. Risk evaluation models of SSBP were constructed based on the serial P value thresholds of polygenetic risk scores (PRSs), polygenic transcriptome risk scores (PTRSs) and their combinations of the identified genes and genetic variants from the TWAS. The TWAS revealed that 2605 genes were significantly associated with SSBP. Among these genes, 69 were differentially expressed according to the microarray analysis. The functional analysis showed that the genes identified in the TWAS were enriched in metabolic process pathways. The PRSs were correlated with PTRSs in the heart atrial appendage, adrenal gland, EBV-transformed lymphocytes, pituitary, artery coronary, artery tibial and whole blood. Multiple logistic regression models revealed that a PRS of P < 0.05 had the best predictive ability compared with other PRSs and PTRSs. The combinations of PRSs and PTRSs did not significantly increase the prediction accuracy of SSBP in the training and validation datasets. CONCLUSIONS: Several known and novel susceptibility genes for SSBP were identified via multitissue TWAS analysis. The risk evaluation model constructed with the PRS of susceptibility genes showed better diagnostic performance than the transcript levels, which could be applied to screen for SSBP high-risk individuals.


Asunto(s)
Presión Sanguínea , Predisposición Genética a la Enfermedad , Estudio de Asociación del Genoma Completo , Humanos , Presión Sanguínea/genética , Perfilación de la Expresión Génica , Hipertensión/genética , Transcriptoma , Polimorfismo de Nucleótido Simple , Masculino , Medición de Riesgo , Femenino , Cloruro de Sodio Dietético/efectos adversos
10.
J Am Chem Soc ; 146(20): 14203-14212, 2024 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-38733560

RESUMEN

Nanomedicines often rely on noncovalent self-assembly and encapsulation for drug loading and delivery. However, challenges such as reproducibility issues due to the multicomponent nature, off-target activation caused by premature drug release, and complex pharmacokinetics arising from assembly dissociation have hindered their clinical translation. In this study, we introduce an innovative design concept termed single molecular nanomedicine (SMNM) based on macrocyclic carrier-drug conjugates. Through the covalent linkage of two chemotherapy drugs to a hypoxia-cleavable macrocyclic carrier, azocalix[4]arene, we obtained two self-included complexes to serve as SMNMs. The intramolecular inclusion feature of the SMNMs has not only demonstrated comprehensive shielding and protection for the drugs but also effectively prevented off-target drug leakage, thereby significantly reducing their side effects and enhancing their antitumor therapeutic efficacy. Additionally, the attributes of being a single component and molecularly dispersed confer advantages such as ease of preparation and good reproducibility for SMNMs, which is desirable for clinical applications.


Asunto(s)
Antineoplásicos , Calixarenos , Portadores de Fármacos , Nanomedicina , Humanos , Portadores de Fármacos/química , Nanomedicina/métodos , Calixarenos/química , Antineoplásicos/química , Antineoplásicos/farmacología , Antineoplásicos/administración & dosificación , Animales , Compuestos Macrocíclicos/química , Ratones , Línea Celular Tumoral , Liberación de Fármacos
11.
J Am Chem Soc ; 2024 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-38728652

RESUMEN

Porous organic polymers (POPs) with inherent porosity, tunable pore environment, and semiconductive property are ideally suitable for application in various advanced semiconductor-related devices. However, owing to the lack of processability, POPs are usually prepared in powder forms, which limits their application in advanced devices. Herein, we demonstrate an example of information storage application of POPs with film form prepared by an electrochemical method. The growth process of the electropolymerized films in accordance with the Volmer-Weber model was proposed by observation of atomic force microscopy. Given the mechanism of the electron transfer system, we verified and mainly emphasized the importance of porosity and interfacial properties of porous polymer films for memristor. As expected, the as-fabricated memristors exhibit good performance on low turn-on voltage (0.65 ± 0.10 V), reliable data storage, and high on/off current ratio (104). This work offers inspiration for applying POPs in the form of electropolymerized films in various advanced semiconductor-related devices.

12.
Anal Chem ; 96(11): 4693-4701, 2024 Mar 19.
Artículo en Inglés | MEDLINE | ID: mdl-38442211

RESUMEN

The cycle time of a standard liquid chromatography (LC) system is the sum of the time for the chromatographic run and the autosampler injection sequence. Although LC separation times in the 1-10 s range have been demonstrated, injection sequences are commonly >15 s, limiting throughput possible with LC separations. Further, such separations are performed on relatively large bore columns requiring flow rates of ≥5 mL/min, thus generating large volumes of mobile phase waste when used for large scale screening and increasing the difficulty in interfacing to mass spectrometry. Here, a droplet injector system was established that replaces the autosampler with a four-port, two-position valve equipped with a 20 nL internal loop interfaced to a syringe pump and a three-axis positioner to withdraw sample droplets from a well plate. In the system, sample and immiscible fluid are pulled alternately from a well plate into a capillary and then through the injection valve. The valve is actuated when sample fills the loop to allow sequential injection of samples at high throughput. Capillary LC columns with 300 µm inner diameter were used to reduce the consumption of mobile phase and sample. The system achieved 96 separations of 20 nL droplet samples containing 3 components in as little as 8.1 min with 5-s cycle time. This system was coupled to a mass spectrometer through an electrospray ionization source for high-throughput chemical reaction screening.

13.
Anal Chem ; 96(15): 5913-5921, 2024 04 16.
Artículo en Inglés | MEDLINE | ID: mdl-38563119

RESUMEN

CRISPR/Cas technology has made great progress in the field of live-cell imaging beyond genome editing. However, effective and easy-to-use CRISPR systems for labeling multiple RNAs of interest are still needed. Here, we engineered a CRISPR/dCas12a system that enables the specific recognition of the target RNA under the guidance of a PAM-presenting oligonucleotide (PAMmer) to mimic the PAM recognition mechanism for DNA substrates. We demonstrated the feasibility and specificity of this system for specifically visualizing endogenous mRNA. By leveraging dCas12a-mediated precursor CRISPR RNA (pre-crRNA) processing and the orthogonality of dCas12a from different bacteria, we further demonstrated the proposed system as a simple and versatile molecular toolkit for multiplexed imaging of different types of RNA transcripts in live cells with high specificity. This programmable dCas12a system not only broadens the RNA imaging toolbox but also facilitates diverse applications for RNA manipulation.


Asunto(s)
Sistemas CRISPR-Cas , ARN , ARN/genética , Sistemas CRISPR-Cas/genética , ARN Guía de Sistemas CRISPR-Cas , Edición Génica/métodos , Bacterias/genética , Precursores del ARN
14.
Anal Chem ; 96(4): 1622-1629, 2024 01 30.
Artículo en Inglés | MEDLINE | ID: mdl-38215213

RESUMEN

The microfluidic chip-based nucleic acid detection method significantly improves the sensitivity since it precisely controls the microfluidic flow in microchannels. Nonetheless, significant challenges still exist in improving the detection efficiency to meet the demand for rapid detection of trace substances. This work provides a novel magnetic herringbone (M-HB) structure in a microfluidic chip, and its advantage in rapid and sensitive detection is verified by taking complementary DNA (cDNA) sequences of human immunodeficiency virus (HIV) detection as an example. The M-HB structure is designed based on controlling the magnetic field distribution in the micrometer scale and is formed by accumulation of magnetic microbeads (MMBs). Hence, M-HB is similar to a nanopore microstructure, which has a higher contact area and probe density. All of the above is conducive to improving sensitivity in microfluidic chips. The M-HB chip is stable and easy to form, which can linearly detect cDNA sequences of HIV quantitatively ranging from 1 to 20 nM with a detection limit of 0.073 nM. Compared to the traditional herringbone structure, this structure is easier to form and release by controlling the magnetic field, which is flexible and helps in further study. Results show that this chip can sensitively detect the cDNA sequences of HIV in blood samples, demonstrating that it is a powerful platform to rapidly and sensitively detect multiple nucleic acid-related viruses of infectious diseases.


Asunto(s)
Infecciones por VIH , Técnicas Analíticas Microfluídicas , Humanos , ADN Complementario , Microesferas , VIH , Fenómenos Magnéticos , Infecciones por VIH/diagnóstico , Técnicas Analíticas Microfluídicas/métodos
15.
Eur J Immunol ; 53(8): e2350420, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37179450

RESUMEN

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that often involves abnormal activation of regulatory IFN genes and regulation of B cells by CD4+ T cells. Radical S-adenosyl methionine domain containing 2 (RSAD2) is a viral suppressor protein regulated by type I IFN, and it has been proven to play an important regulatory role in SLE. However, the mechanism by which RSAD2 participates in the pathogenesis of SLE is unclear. In this study, we observed higher expression levels of RSAD2 in CD4+ T-cell subsets from the peripheral blood of SLE patients than in those from healthy controls by bioinformatics analysis and validation experiments. We analyzed the expression of RSAD2 in CD4+ T cells of patients with SLE and other autoimmune diseases. In addition, we found that the expression of RSAD2 in CD4+ T cells might be regulated by IFN-α, and RSAD2 significantly affected the differentiation of Th17 cells and T follicular helper (Tfh) cells. Our findings underlined that RSAD2 may promote B-cell activation by promoting the differentiation of Th17 and Tfh cells in SLE patients, a process that is regulated by IFN-α.


Asunto(s)
Lupus Eritematoso Sistémico , Oxidorreductasas actuantes sobre Donantes de Grupo CH-CH , Humanos , Células Th17 , Interferón-alfa , Células T Auxiliares Foliculares , Subgrupos de Linfocitos T , Lupus Eritematoso Sistémico/genética , Linfocitos T Colaboradores-Inductores
16.
Biochem Biophys Res Commun ; 736: 150821, 2024 Oct 18.
Artículo en Inglés | MEDLINE | ID: mdl-39454302

RESUMEN

Multidrug and toxic compound extrusion proteins (MATE) can transport small organic molecules in and out of cells and participate in detoxification, nutrient absorption, disease resistance and plant development processes. These compounds are widely distributed in plants. However, the mechanism by which MATE affects grain development remains elusive. In this study, we studied a MATE transporter, OsMATE2, which localized on the membrane. The CRISPR-Cas9 (CR) knockout line of OsMATE2 presented obvious decreases in grain weight. In addition, root development was also affected. Two proteins that interact with OsMATE2, namely, manganese-superoxide dismutase (Mn-SOD) and poly(A)-binding protein (PABP), were identified from a screening of yeast library. The results were validated through yeast two-hybrid and bimolecular fluorescence complementation experiments. The CRISPR-Cas9 (CR) knockout lines of Mn-SOD and PABP presented increased grain size and weight. Our findings demonstrated that OsMATE2 interacts with Mn-SOD and PABP to regulate grain development in rice.

17.
Radiology ; 310(3): e232605, 2024 03.
Artículo en Inglés | MEDLINE | ID: mdl-38530176

RESUMEN

Background Detection of extranodal extension (ENE) at pathology is a poor prognostic indicator for rectal cancer, but whether ENE can be identified at pretreatment MRI is, to the knowledge of the authors, unknown. Purpose To evaluate the performance of pretreatment MRI in detecting ENE using a matched pathologic reference standard and to assess its prognostic value in patients with rectal cancer. Materials and Methods This single-center study included a prospective development data set consisting of participants with rectal adenocarcinoma who underwent pretreatment MRI and radical surgery (December 2021 to January 2023). MRI characteristics were identified by their association with ENE-positive nodes (χ2 test and multivariable logistic regression) and the performance of these MRI features was assessed (area under the receiver operating characteristic curve [AUC]). Interobserver agreement was assessed by Cohen κ coefficient. The prognostic value of ENE detected with MRI for predicting 3-year disease-free survival was assessed by Cox regression analysis in a retrospective independent validation cohort of patients with locally advanced rectal cancer (December 2019 to July 2020). Results The development data set included 147 participants (mean age, 62 years ± 11 [SD]; 87 male participants). The retrospective cohort included 110 patients (mean age, 60 years ± 9; 79 male participants). Presence of vessel interruption and fusion (both P < .001), heterogeneous internal structure, and the broken-ring and tail signs (odds ratio range, 4.10-23.20; P value range, <.001 to .002) were predictors of ENE at MRI, and together achieved an AUC of 0.91 (95% CI: 0.88, 0.93) in detecting ENE. Interobserver agreement was moderate for the presence of vessel interruption and fusion (κ = 0.46 for both) and substantial for others (κ = 0.61-0.67). The presence of ENE at pretreatment MRI was independently associated with worse 3-year disease-free survival (hazard ratio, 3.00; P = .02). Conclusion ENE can be detected at pretreatment MRI, and its presence was associated with worse prognosis for patients with rectal cancer. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Eberhardt in this issue.


Asunto(s)
Neoplasias Primarias Secundarias , Neoplasias del Recto , Humanos , Masculino , Persona de Mediana Edad , Extensión Extranodal , Pronóstico , Estudios Prospectivos , Estudios Retrospectivos , Neoplasias del Recto/diagnóstico por imagen , Imagen por Resonancia Magnética
18.
Small ; : e2406070, 2024 Aug 11.
Artículo en Inglés | MEDLINE | ID: mdl-39128138

RESUMEN

This work reports a strategy that integrates the carbon nanotube (CNT) supporting, ultrathin carbon coating and oxygen defect generation to fabricate the RuO2 based catalysts toward the pH-universal hydrogen evolution reaction (HER) with high efficiencies. Specifically, the CNT supported RuO2 nanoparticles with ultrathin carbon loricae and rich oxygen vacancies at the surface (C@OV-RuO2/CNTs-325) have been synthesized. The C@OV-RuO2/CNTs-325 shows superior activities and excellent durability for the HER. It only requires overpotentials of 36.1, 18.0, and 19.3 mV to deliver -10 mA cm-2 in the acidic, neutral, and alkaline media, respectively. Its HER activities are comparable to that of the Pt/C in the acidic media but higher than those of the Pt/C in the neutral and alkaline media. The C@OV-RuO2/CNTs-325 shows excellent HER durability with no activity losses for > 500 h in the acidic, neutral or alkaline media at -250 mA cm-2. The density-functional-theory calculations indicate that the CNT supporting, the carbon coating, and the OVs can modulate the d-band centers of Ru, increasing the HER activities of C@OV-RuO2/CNTs-325, and stabilize the Ru atoms in the catalyst, increasing the durability of the C@OV-RuO2/CNTs-325. More interestingly, the C@OV-RuO2/CNTs-325 shows great potential for practical applications toward overall seawater splitting.

19.
Small ; : e2405946, 2024 Sep 09.
Artículo en Inglés | MEDLINE | ID: mdl-39246162

RESUMEN

Under large current densities, the excessive hydroxide ion (OH) consumption hampers alkaline water splitting involving the oxygen evolution reaction (OER). High OH concentration (≈30 wt.%) is often used to enhance the catalytic activity of OER, but it also leads to higher corrosion in practical systems. To achieve higher catalytic activity in low OH concentration, catalysts on magnetic frame (CMF) are built to utilize the local magnetic convection induced from the host frame's magnetic field distributions. This way, a higher reaction rate can be achieved in relatively lower OH concentrations. A CMF model system with catalytically active CoFeOx nanograins grown on the magnetic Ni foam is demonstrated. The OER current of CoFeOx@NF receives ≈90% enhancement under 400 mT (900 mA cm-2 at 1.65 V) compared to that in zero field, and exhibits remarkable durability over 120 h. As a demonstration, the water-splitting performance sees a maximum 45% magnetic enhancement under 400 mT in 1 m KOH (700 mA cm-2 at 2.4 V), equivalent to the concentration enhancement of the same electrode in a more corrosive 2 m KOH electrolyte. Therefore, the catalyst-on-magnetic-frame strategy can make efficient use of the catalysts and achieve higher catalytic activity in low OH concentration by harvesting local magnetic convection.

20.
Planta ; 259(2): 50, 2024 Jan 29.
Artículo en Inglés | MEDLINE | ID: mdl-38285114

RESUMEN

MAIN CONCLUSION: The oxidosqualene cyclases (OSCs) generating triterpenoid skeletons in Cyclocarya paliurus were identified for the first time, and two uridine diphosphate (UDP)-glycosyltransferases (UGTs) catalyzing the glycosylation of flavonoids were characterized. Cyclocarya paliurus, a native rare dicotyledonous plant in China, contains an abundance of triterpenoid saponins and flavonoid glycosides that exhibit valuable pharmaceutical effects in preventing hypertension, hyperlipidemia, and diabetes. However, the molecular mechanism explaining the biosynthesis of triterpenoid saponin and flavonoid glycoside in C. paliurus remains unclear. In this study, the triterpene content in different tissues and the expression pattern of genes encoding the key enzymes associated with triterpenoid saponin and flavonoid glycoside biosynthesis were studied using transcriptome and metabolome analysis. The eight upstream oxidosqualene cyclases (OSCs) involved in triterpenoid saponin biosynthesis were functionally characterized, among them CpalOSC6 catalyzed 2,3;22,23-dioxidosqualene to form 3-epicabraleadiol; CpalOSC8 cyclized 2,3-oxidosqualene to generate dammarenediol-II; CpalOSC2 and CpalOSC3 produced ß-amyrin and CpalOSC4 produced cycloartenol, while CpalOSC2-CpalOSC5, CpalOSC7, and CpalOSC8 all produced lanosterol. However, no catalytic product was detected for CpalOSC1. Moreover, two downstream flavonoid uridine diphosphate (UDP)-glycosyltransferases (UGTs) (CpalUGT015 and CpalUGT100) that catalyze the last step of flavonoid glycoside biosynthesis were functionally elucidated. These results uncovered the key genes involved in the biosynthesis of triterpenoid saponins and flavonoid glycosides in C. paliurus that could be applied to produce flavonoid glycosides and key triterpenoid saponins in the future via a synthetic strategy.


Asunto(s)
Saponinas , Escualeno/análogos & derivados , Triterpenos , Glicósidos , Flavonoides , Saponinas/genética , Glicosiltransferasas , Uridina Difosfato
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