Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 356
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Cell ; 170(3): 492-506.e14, 2017 Jul 27.
Artículo en Inglés | MEDLINE | ID: mdl-28753426

RESUMEN

Interferon-α (IFNα) signaling is essential for antiviral response via induction of IFN-stimulated genes (ISGs). Through a non-biased high-throughput RNAi screening of 711 known epigenetic modifiers in cellular models of IFNα-mediated inhibition of HBV replication, we identified methyltransferase SETD2 as a critical amplifier of IFNα-mediated antiviral immunity. Conditional knockout mice with hepatocyte-specific deletion of Setd2 exhibit enhanced HBV infection. Mechanistically, SETD2 directly mediates STAT1 methylation on lysine 525 via its methyltransferase activity, which reinforces IFN-activated STAT1 phosphorylation and antiviral cellular response. In addition, SETD2 selectively catalyzes the tri-methylation of H3K36 on promoters of some ISGs such as ISG15, leading to gene activation. Our study identifies STAT1 methylation on K525 catalyzed by the methyltransferase SETD2 as an essential signaling event for IFNα-dependent antiviral immunity and indicates potential of SETD2 in controlling viral infections.


Asunto(s)
Virus de la Hepatitis B/fisiología , Hepatitis B Crónica/inmunología , N-Metiltransferasa de Histona-Lisina/metabolismo , Interferón-alfa/inmunología , Factor de Transcripción STAT1/genética , Animales , Línea Celular , Línea Celular Tumoral , Epigénesis Genética , Hepatitis B Crónica/virología , Hepatocitos/metabolismo , Histonas/metabolismo , Humanos , Ratones , Fosforilación , Dominios Proteicos , Interferencia de ARN , Transcripción Genética , Replicación Viral
2.
Nature ; 628(8009): 765-770, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38658685

RESUMEN

Solar fuels offer a promising approach to provide sustainable fuels by harnessing sunlight1,2. Following a decade of advancement, Cu2O photocathodes are capable of delivering a performance comparable to that of photoelectrodes with established photovoltaic materials3-5. However, considerable bulk charge carrier recombination that is poorly understood still limits further advances in performance6. Here we demonstrate performance of Cu2O photocathodes beyond the state-of-the-art by exploiting a new conceptual understanding of carrier recombination and transport in single-crystal Cu2O thin films. Using ambient liquid-phase epitaxy, we present a new method to grow single-crystal Cu2O samples with three crystal orientations. Broadband femtosecond transient reflection spectroscopy measurements were used to quantify anisotropic optoelectronic properties, through which the carrier mobility along the [111] direction was found to be an order of magnitude higher than those along other orientations. Driven by these findings, we developed a polycrystalline Cu2O photocathode with an extraordinarily pure (111) orientation and (111) terminating facets using a simple and low-cost method, which delivers 7 mA cm-2 current density (more than 70% improvement compared to that of state-of-the-art electrodeposited devices) at 0.5 V versus a reversible hydrogen electrode under air mass 1.5 G illumination, and stable operation over at least 120 h.

3.
Immunity ; 50(3): 600-615.e15, 2019 03 19.
Artículo en Inglés | MEDLINE | ID: mdl-30824325

RESUMEN

CCR7 chemokine receptor stimulation induces rapid but transient dendritic cell (DC) migration toward draining lymph nodes, which is critical for the initiation of protective immunity and maintenance of immune homeostasis. The mechanisms for terminating CCR7-mediated DC migration remain incompletely understood. Here we have identified a long non-coding RNA lnc-Dpf3 whose feedback restrained CCR7-mediated DC migration. CCR7 stimulation upregulated lnc-Dpf3 via removing N6-methyladenosine (m6A) modification to prevent RNA degradation. DC-specific lnc-Dpf3 deficiency increased CCR7-mediated DC migration, leading to exaggerated adaptive immune responses and inflammatory injuries. Mechanistically, CCR7 stimulation activated the HIF-1α transcription factor pathway in DCs, leading to metabolic reprogramming toward glycolysis for DC migration. lnc-Dpf3 directly bound to HIF-1α and suppressed HIF-1α-dependent transcription of the glycolytic gene Ldha, thus inhibiting DC glycolytic metabolism and migratory capacity. We demonstrate a critical role for CCR7-inducible lnc-Dpf3 in coupling epigenetic and metabolic pathways to feedback-control DC migration and inflammatory responses.


Asunto(s)
Movimiento Celular/genética , Proteínas de Unión al ADN/genética , Glucólisis/genética , Subunidad alfa del Factor 1 Inducible por Hipoxia/genética , Receptores CCR7/genética , Factores de Transcripción/genética , Inmunidad Adaptativa/genética , Animales , Línea Celular , Células Dendríticas/patología , Epigénesis Genética/genética , Regulación de la Expresión Génica/genética , Células HEK293 , Humanos , Inflamación/genética , Inflamación/patología , Ganglios Linfáticos/patología , Redes y Vías Metabólicas/genética , Ratones , Ratones Endogámicos C57BL , Transcripción Genética/genética , Regulación hacia Arriba/genética
4.
Immunity ; 49(4): 640-653.e5, 2018 10 16.
Artículo en Inglés | MEDLINE | ID: mdl-30332630

RESUMEN

Tissue-resident mast cells are associated with many inflammatory and physiological processes. Although mast cells arise from the yolk sac, the exact ontogeny of adult mast cells remains unclear. Here we have investigated the hematopoietic origin of mast cells using fate-mapping systems. We have shown that early erythro-myeloid progenitors (EMPs), late EMPs, and definitive hematopoietic stem cells (HSCs) each gave rise to mast cells in succession via an intermediate integrin ß7+ progenitor. From late embryogenesis to adult, early EMP-derived mast cells were largely replaced by late EMP-derived cells in most connective tissues except adipose and pleural cavity. Thus, mast cells with distinct origin displayed tissue-location preferences: early EMP-derived cells were limited to adipose and pleural cavity and late EMP-derived cells dominated most connective tissues, while HSC-derived cells were a main group in mucosa. Therefore, embryonic origin shapes the heterogeneity of adult mast cells, with diverse functions in immunity and development.


Asunto(s)
Células Eritroides/inmunología , Mastocitos/inmunología , Células Progenitoras Mieloides/inmunología , Animales , Linaje de la Célula/inmunología , Células Cultivadas , Tejido Conectivo/inmunología , Tejido Conectivo/metabolismo , Embrión de Mamíferos/citología , Embrión de Mamíferos/embriología , Embrión de Mamíferos/inmunología , Células Eritroides/citología , Células Eritroides/metabolismo , Células Madre Hematopoyéticas/citología , Células Madre Hematopoyéticas/inmunología , Células Madre Hematopoyéticas/metabolismo , Cadenas beta de Integrinas/inmunología , Cadenas beta de Integrinas/metabolismo , Mastocitos/citología , Mastocitos/metabolismo , Ratones Transgénicos , Células Progenitoras Mieloides/citología , Células Progenitoras Mieloides/metabolismo
5.
Proc Natl Acad Sci U S A ; 121(5): e2312929121, 2024 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-38252825

RESUMEN

Immunotherapy is a promising approach for treating metastatic breast cancer (MBC), offering new possibilities for therapy. While checkpoint inhibitors have shown great progress in the treatment of metastatic breast cancer, their effectiveness in patients with bone metastases has been disappointing. This lack of efficacy seems to be specific to the bone environment, which exhibits immunosuppressive features. In this study, we elucidate the multiple roles of the sialic acid-binding Ig-like lectin (Siglec)-15/sialic acid glyco-immune checkpoint axis in the bone metastatic niche and explore potential therapeutic strategies targeting this glyco-immune checkpoint. Our research reveals that elevated levels of Siglec-15 in the bone metastatic niche can promote tumor-induced osteoclastogenesis as well as suppress antigen-specific T cell responses. Next, we demonstrate that antibody blockade of the Siglec-15/sialic acid glyco-immune checkpoint axis can act as a potential treatment for breast cancer bone metastasis. By targeting this pathway, we not only aim to treat bone metastasis but also inhibit the spread of metastatic cancer cells from bone lesions to other organs.


Asunto(s)
Neoplasias Óseas , Neoplasias de la Mama , Humanos , Femenino , Neoplasias de la Mama/tratamiento farmacológico , Ácido N-Acetilneuramínico , Neoplasias Óseas/tratamiento farmacológico , Inmunoterapia , Anticuerpos Bloqueadores
6.
Nat Immunol ; 15(7): 612-22, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24859449

RESUMEN

Excessive activation of dendritic cells (DCs) leads to the development of autoimmune and inflammatory diseases, which has prompted a search for regulators of DC activation. Here we report that Rhbdd3, a member of the rhomboid family of proteases, suppressed the activation of DCs and production of interleukin 6 (IL-6) triggered by Toll-like receptors (TLRs). Rhbdd3-deficient mice spontaneously developed autoimmune diseases characterized by an increased abundance of the TH17 subset of helper T cells and decreased number of regulatory T cells due to the increase in IL-6 from DCs. Rhbdd3 directly bound to Lys27 (K27)-linked polyubiquitin chains on Lys302 of the modulator NEMO (IKKγ) via the ubiquitin-binding-association (UBA) domain in endosomes. Rhbdd3 further recruited the deubiquitinase A20 via K27-linked polyubiquitin chains on Lys268 to inhibit K63-linked polyubiquitination of NEMO and thus suppressed activation of the transcription factor NF-κB in DCs. Our data identify Rhbdd3 as a critical regulator of DC activation and indicate K27-linked polyubiquitination is a potent ubiquitin-linked pattern involved in the control of autoimmunity.


Asunto(s)
Proteínas Reguladoras de la Apoptosis/fisiología , Autoinmunidad , Células Dendríticas/inmunología , Interleucina-6/biosíntesis , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Ubiquitinación , Animales , Interleucina-6/antagonistas & inhibidores , Lisina/metabolismo , Ratones , Ratones Endogámicos C57BL , FN-kappa B/fisiología , Estructura Terciaria de Proteína , Linfocitos T/inmunología , Receptores Toll-Like/fisiología
8.
Mol Ther ; 32(5): 1219-1237, 2024 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-38449313

RESUMEN

Bone cancer is common and severe. Both primary (e.g., osteosarcoma, Ewing sarcoma) and secondary (e.g., metastatic) bone cancers lead to significant health problems and death. Currently, treatments such as chemotherapy, hormone therapy, and radiation therapy are used to treat bone cancer, but they often only shrink or slow tumor growth and do not eliminate cancer completely. The bone microenvironment contributes unique signals that influence cancer growth, immunogenicity, and metastasis. Traditional cancer therapies have limited effectiveness due to off-target effects and poor distribution on bones. As a result, therapies with improved specificity and efficacy for treating bone tumors are highly needed. One of the most promising strategies involves the targeted delivery of pharmaceutical agents to the site of bone cancer by introduction of bone-targeting moieties, such as bisphosphonates or oligopeptides. These moieties have high affinities to the bone hydroxyapatite matrix, a structure found exclusively in skeletal tissue, and can enhance the targeting ability and efficacy of anticancer drugs when combating bone tumors. This review focuses on the engineering of small molecules and proteins with bone-targeting moieties for the treatment of bone tumors.


Asunto(s)
Antineoplásicos , Neoplasias Óseas , Humanos , Neoplasias Óseas/tratamiento farmacológico , Neoplasias Óseas/terapia , Antineoplásicos/uso terapéutico , Antineoplásicos/farmacología , Animales , Difosfonatos/uso terapéutico , Difosfonatos/farmacología , Difosfonatos/química , Sistemas de Liberación de Medicamentos/métodos , Osteosarcoma/tratamiento farmacológico , Osteosarcoma/patología , Sarcoma de Ewing/tratamiento farmacológico , Sarcoma de Ewing/terapia , Terapia Molecular Dirigida/métodos , Microambiente Tumoral/efectos de los fármacos
9.
J Infect Dis ; 2024 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-38586880

RESUMEN

AIMS: We conducted a Mendelian randomization (MR) study to elucidate the anti-infective effects of ticagrelor. METHODS AND RESULTS: Single-nucleotide polymorphisms (SNPs) associated with serum levels of ticagrelor or its major metabolite AR-C124910XX (ARC) in the PLATelet inhibition and patient Outcomes trial were selected as genetic proxies for ticagrelor exposure. Positive control analyses indicated that genetically surrogated serum ticagrelor levels (six SNPs) but not ARC levels (two SNPs) were significantly associated with lower risks of coronary heart disease. Therefore, the six SNPs were used as genetic instruments for ticagrelor exposure, and the genome-wide association study data for five infection outcomes were derived from the UK Biobank and FinnGen consortium. The two-sample MR analyses based on inverse variance-weighted methods indicated that genetic liability to ticagrelor exposure could reduce the risk of bacterial pneumonia (odds ratio [OR]: 0.82, 95% confidence interval [CI]: 0.71-0.95, P = 8.75E-03) and sepsis (OR: 0.83, 95% CI: 0.73-0.94, P = 3.69E-03); however, no causal relationship between ticagrelor exposure and upper respiratory infection, pneumonia, and urinary tract infection was detected. Extensive sensitivity analyses corroborated these findings. CONCLUSION: Our MR study provides further evidence for the preventive effects of ticagrelor on bacterial pneumonia and sepsis.

10.
Phys Chem Chem Phys ; 26(2): 1113-1124, 2024 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-38098463

RESUMEN

A new type of adsorbent, a Prussian blue analog-based copper-aluminum layered double hydroxide (PBA@CuAl-LDH), was successfully synthesized using a one-step method for the removal of radioactive Cs+ from wastewater. The adsorption performance, characteristics and the underlying adsorption mechanism of PBA@CuAl-LDH were systematically examined. The results showed that PBA@CuAl-LDH exhibited excellent adsorption performance, with a maximum adsorption capacity of 109.2 mg g-1. Over 85% of PBA@CuAl-LDH can be recycled, and the material exhibited only a 6.6% loss in adsorption performance. The adsorption process was well-fitted using the pseudo-second-order kinetic model and the Freundlich isotherm model, revealing the surface heterogeneity of the composite adsorbent. A molecular model of PBA@CuAl-LDH was constructed by combining density functional theory and multiple instrumental characterization techniques. Our results indicate that PBA crystals can be generated between layers and on the surface. Ion exchange was revealed as the main adsorption mechanism of Cs+ by PBA@CuAl-LDH. Specifically, the interstitial spaces of the PBA crystals generated between the layers and on the surface played an important role in ion exchange. These findings provide concrete theoretical support for radioactive pollution control and have significant value in directing the fabrication of cesium removal materials and their future engineering application.

11.
Pestic Biochem Physiol ; 198: 105727, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38225066

RESUMEN

The citrus red mite, Panonychus citri (McGregor), is a globally important pest that has developed severe resistance to various pesticides. Lufenuron has been widely used in the control of the related pests in citrus orchard ecosystem. In this study, the susceptibilities of egg, larva, deutonymph and female adult of P. citri to lufenuron was determined, and the LC50 values were 161.354 mg/L, 49.595 mg/L, 81.580 mg/L, and 147.006 mg/L, respectively. Life-table analysis indicated that the fecundities were significantly increased by 11.86% and 26.84% after the mites were treated with LC20 concentrations of lufenuron at the egg or deutonymph stages, respectively. After eggs were treated with lufenuron, the immature stage and longevity were also affected, and resulted in a significant increase in r, R0 and λ. After exposure of female adults to LC20 of lufenuron, the fecundity and longevity of F0 generation significantly decreased by 31.99% and 10.94%, respectively. Furthermore, the expression level of EcR and Vg was significantly inhibited upon mites was treated with lufenuron. However, lufenuron exposure has a positive effect on fecundity and R0 in F1 generation, the expression of all reproduction-related genes was significantly up-regulated. In conclusion, there was a stimulating effect on the offspring population. Our results will contribute to the assessment of the resurgence of P. citri in the field after the application of lufenuron and the development of integrated pest control strategies in citrus orchards.


Asunto(s)
Benzamidas , Fluorocarburos , Ácaros , Tetranychidae , Animales , Ecosistema , Reproducción
12.
J Environ Manage ; 356: 120432, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38479282

RESUMEN

Biodegradation of soil organic matter (SOM), which involves greenhouse gas (GHG) emissions, plays an essential role in the global carbon cycle. Over the past few decades, this has become an important research focus, particularly in natural ecosystems. SOM biodegradation significantly affects contaminants in the environment, such as mercury (Hg) methylation, producing highly toxic methylmercury (MeHg). However, the potential link between GHG production from SOM turnover in contaminated soils and biogeochemical processes involving contaminants remains unclear. In this study, we investigated the dynamics of GHG, MeHg production, and the relationship between biogeochemical processes in soils from two typical Hg mining sites. The two contaminated soils have different pathways, explaining the significant variations in GHG and MeHg production. The divergence of the microbial communities in these two biogeochemical processes is essential. In addition to the microbial role, abiotic factors such as Hg species can significantly affect MeHg production. On the other hand, we found an inverse relationship between CH4 and MeHg, suggesting that carbon emission reduction policies and management could inadvertently increase the MeHg levels. This highlights the need for an eclectic approach to organic carbon sequestration and contaminant containment. These findings suggest that it is difficult to establish a general pattern to describe and explain the SOM degradation and MeHg production in contaminated soils within the specific scenarios. However, this study provides a case study and helpful insights for further understanding the links between environmental risks and carbon turnover in Hg mining areas.


Asunto(s)
Mercurio , Compuestos de Metilmercurio , Oryza , Contaminantes del Suelo , Suelo , Ecosistema , Contaminantes del Suelo/análisis , Mercurio/análisis , Carbono , Biodegradación Ambiental , Monitoreo del Ambiente
13.
Molecules ; 29(3)2024 Jan 26.
Artículo en Inglés | MEDLINE | ID: mdl-38338349

RESUMEN

Safflower (Carthamus tinctorius L.) has been recognized for its medicinal value, but there have been limited studies on the glycosyltransferases involved in the biosynthesis of flavonoid glycosides from safflower. In this research, we identified two highly efficient flavonoid O-glycosyltransferases, CtOGT1 and CtOGT2, from safflower performing local BLAST alignment. By constructing a prokaryotic expression vector, we conducted in vitro enzymatic reactions and discovered that these enzymes were capable of catalyzing two-step O-glycosylation using substrates such as kaempferol, quercetin, and eriodictyol. Moreover, they exhibited efficient catalytic activity towards various compounds, including flavones (apigenin, scutellarein), dihydrochalcone (phloretin), isoflavones (genistein, daidzein), flavanones (naringenin, glycyrrhizin), and flavanonols (dihydrokaempferol), leading to the formation of O-glycosides. The broad substrate specificity of these enzymes is noteworthy. This study provides valuable insights into the biosynthetic pathways of flavonoid glycosides in safflower. The discovery of CtOGT1 and CtOGT2 enhances our understanding of the enzymatic processes involved in synthesizing flavonoid glycosides in safflower, contributing to the overall comprehension of secondary metabolite biosynthesis in this plant species.


Asunto(s)
Carthamus tinctorius , Flavonas , Carthamus tinctorius/metabolismo , Glicosiltransferasas/metabolismo , Flavonoides/metabolismo , Glicósidos/metabolismo , Flavonas/metabolismo
14.
Zhongguo Zhong Yao Za Zhi ; 49(2): 370-378, 2024 Jan.
Artículo en Zh | MEDLINE | ID: mdl-38403313

RESUMEN

Digitoxin, an important secondary metabolite of Digitalis purpurea, is a commonly used cardiotonic in clinical practice. 3ß-Hydroxysteroid dehydrogenase(3ßHSD) is a key enzyme involved in the biosynthesis of digitoxin. It belongs to the short-chain dehydrogenase/reductase(SDR) family, playing a role in the biosynthesis of cardiac glycosides by oxidizing and isomerizing the precursor sterol. In this study, two 3ßHSD genes were cloned from D. purpurea. The results showed that the open reading frame(ORF) of Dp3ßHSD1 was 780 bp, encoding 259 amino acid residues. The ORF of Dp3ßHSD2 was 774 bp and encoded 257 residues. Dp3ßHSD1/2 had the cofactor binding site TGxxxA/GxG and the catalytic site YxxxK. In vitro experiments confirmed that Dp3ßHSD1/2 catalyzed the generation of progesterone from pregnenolone, and Dp3ßHSD1 had stronger catalytic capacity than Dp3ßHSD2. The expression level of Dp3ßHSD1 was much higher than that of Dp3ßHSD2 in leaves, and digitoxin was only accumulated in leaves. The results implied that Dp3ßHSD1 played a role in the dehydrogenation of pregnenolone to produce progesterone in the biosynthesis of digitoxin. This study provides a reference for further exploring the biosynthetic pathway of cardiac glycosides in D. purpurea.


Asunto(s)
Digitoxina , Progesterona , Clonación Molecular , Pregnenolona/metabolismo , Hidroxiesteroide Deshidrogenasas
15.
Zhongguo Zhong Yao Za Zhi ; 49(9): 2410-2421, 2024 May.
Artículo en Zh | MEDLINE | ID: mdl-38812142

RESUMEN

Sequential catalysis by ent-copalyl diphosphate(CPS) and ent-kaurene synthase(KS) is a critical step for plants to initiate the biosynthesis of gibberellin with geranylgeranyl pyrophosphate(GGPP) as the substrate. This study mined the transcriptome data of Stellera chamaejasme and cloned two key diterpene synthase genes, SchCPS and SchKS, involved in the gibberellin pathway. The two genes had the complete open reading frames of 2 595 bp and 1 701 bp, encoding two hydrophilic proteins composed of 864 and 566 amino acid residues and with the relative molecular mass of 97.9 kDa and 64.6 kDa and the theoretical isoelectric points of 5.61 and 6.12, respectively. Sequence comparison and phylogenetic tree showed that SchCPS contained LHS, PNV, and DxDD motifs conserved in the CPS family and was categorized in the TPS-c subfamily, while SchKS contained DDxxD, NSE/DTE and PIx motifs conserved in the KS family and was categorized in the TPS-e subfamily. Functional validation showed that SchCPS catalyzed the protonation and cyclization of GGPP to ent-CPP, while SchKS acted on ent-CPP dephosphorylation and re-cyclization to ent-kaurene. In this study, the full-length sequences of SchCPS and SchKS were cloned and functionally verified for the first time, which not only enriched the existing CPS and KS gene libraries but also laid a foundation for the cloning and biosynthesis pathway analysis of more genes involved in the synthesis of active components in S. chamaejasme.


Asunto(s)
Transferasas Alquil y Aril , Filogenia , Proteínas de Plantas , Thymelaeaceae , Transferasas Alquil y Aril/genética , Transferasas Alquil y Aril/metabolismo , Transferasas Alquil y Aril/química , Thymelaeaceae/genética , Thymelaeaceae/enzimología , Thymelaeaceae/química , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Proteínas de Plantas/química , Secuencia de Aminoácidos , Diterpenos de Tipo Kaurano/metabolismo , Diterpenos de Tipo Kaurano/química , Alineación de Secuencia , Clonación Molecular
16.
J Am Chem Soc ; 145(51): 27939-27949, 2023 Dec 27.
Artículo en Inglés | MEDLINE | ID: mdl-38090815

RESUMEN

Photoelectrochemical carbon dioxide reduction (PEC-CO2R) represents a promising approach for producing renewable fuels and chemicals using solar energy. However, attaining even modest solar-to-fuel (STF) conversion efficiency often necessitates the use of costly semiconductors and noble-metal catalysts. Herein, we present a Cu2O/Ga2O3/TiO2 photocathode modified with Sn/SnOx catalysts through a simple photoelectrodeposition method. It achieves a remarkable half-cell STF efficiency of ∼0.31% for the CO2R in aqueous KHCO3 electrolyte, under AM 1.5 G illumination. The system enables efficient production of syngas (FE: ∼62%, CO/H2 ≈ 1:2) and formate (FE: ∼38%) with a consistent selectivity over a wide potential range, from +0.34 to -0.16 V vs the reversible hydrogen electrode. We ascribe the observed performance to the favorable optoelectronic characteristics of our Cu2O heterostructure and the efficient Sn/SnOx catalysts incorporated in the PEC-CO2R reactions. Through comprehensive experimental investigations, we elucidate the indispensable role of Cu2O buried p-n junctions in generating a high photovoltage (∼1 V) and enabling efficient bulk charge separation (up to ∼70% efficiency). Meanwhile, we discover that the deposited Sn/SnOx catalysts have critical dual effects on the overall performance of the PEC devices, serving as active CO2R catalysts as well as the semiconductor front contact. It could facilitate interfacial electron transfer between the catalysts and the semiconductor device for CO2R by establishing a barrier-free ohmic contact.

17.
Appl Opt ; 62(6): 1557-1566, 2023 Feb 20.
Artículo en Inglés | MEDLINE | ID: mdl-36821317

RESUMEN

A method of optical fiber composite overhead ground wire (OPGW) positioning based on a Brillouin distributed optical fiber sensor and machine learning is proposed. A distributed Brillouin optical time-domain reflectometry (BOTDR) and Brillouin optical time-domain analyzer (BOTDA) are designed, where the ranges of BOTDR and the BOTDA are 110 km and 125 km, respectively. An unsupervised machine learning method density-based spatial clustering of applications with noise (DBSCAN) is proposed to automatically identify the splicing point based on the Brillouin frequency shift (BFS) difference of adjacent sections. An adaptive parameter selection method based on k-distance is adapted to overcome the parameter sensitivity. The validity of the proposed DBSCAN algorithm is greater than 96%, which is evaluated by three commonly external validation indices with five typical BFS curves. According to the clustering results of different fiber cores and the tower schedule of the OPGW, the connecting towers are distinguished, which is proved as a 100% recognition rate. According to the identification results of different fiber cores of both the OPGW cables and tower schedule, the connecting towers can be distinguished, and the distributed strain information is extracted directly from the BFS to strain. The abnormal region is positioned and warned according to the distributed strain measurements. The method proposed herein significantly improves the efficiency of fault positioning and early warning, which means a higher operational reliability of the OPGW cables.

18.
J Biopharm Stat ; 33(1): 60-76, 2023 01 02.
Artículo en Inglés | MEDLINE | ID: mdl-35723946

RESUMEN

In early phase oncology drug development, single arm proof-of-concept (POC) studies are increasingly being used to drive the early decisions for future development of the drug. Decision-makings based on such studies, typically involving small sample size and early surrogate efficacy endpoints, are extremely challenging. In particular, given the tremendous competition in the development of immunotherapies, expedition of the most promising programs is desired. To this end, we have proposed a Bayesian three-tier approach to facilitate the decision-making process, inheriting all the benefits of Bayesian decision-making approaches and formally allowing the option of acceleration. With pre-specified Bayesian decision criteria, three types of decisions regarding the future development of the drug can be made: (1) terminating the program, (2) further investigation, considering totality of evidence or additional POC studies, and (3) accelerating the program. We further proposed a Bayesian adaptive three-tier (BAT) design, extending the decision-making approach to incorporate adaptive thresholds and allow for continuous monitoring of the study. We compare the performance of the proposed methods with some other existing methods through simulations.


Asunto(s)
Oncología Médica , Proyectos de Investigación , Humanos , Teorema de Bayes , Tamaño de la Muestra , Desarrollo de Medicamentos
19.
J Enzyme Inhib Med Chem ; 38(1): 2229070, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37381729

RESUMEN

Fifteen 1,2,4-triazole derivatives were synthesised in this study and their MIC values against Mycobacterium tuberculosis (Mtb) ranged from 2 to 32 µg/mL. Furthermore, their antimycobacterial activity was positively correlated with the KatG enzyme docking score. Among the 15 compounds, compound 4 showed the strongest bactericidal activity with an MIC of 2 µg/mL. The selectivity index of compound 4 is more than 10, indicating that the compound has low toxicity to animal cells and has the potential to become a drug. Molecular docking indicates that compound 4 can bind firmly to the Mtb KatG active site. The experimental results showed that compound 4 inhibited Mtb KatG and caused the accumulation of ROS in Mtb cells. We speculate that compound 4 causes the accumulation of ROS by inhibiting KatG, and ROS produces oxidative destruction, leading to the death of Mtb. This study provides a new idea for the development of novel anti-Mtb drugs.


Asunto(s)
Mycobacterium tuberculosis , Animales , Simulación del Acoplamiento Molecular , Especies Reactivas de Oxígeno , Triazoles/farmacología
20.
Chem Biodivers ; 20(2): e202200965, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36567254

RESUMEN

Tuberculosis (TB) remains a major threat to human health. Due to the prevalence of drug-resistant Mycobacterium tuberculosis (Mtb), it is urgent to discover drugs with new mechanisms of action (MOA) to ensure effectiveness against strains that are resistant to existing TB drugs. Cynoglossum lanceolatum Forsk was used to treat TB in Traditional Chinese Medicine. In this article, shikonin, the anti-Mtb active component, was obtained from the whole herb extract of C. lanceolatum by bioassay-guided isolation. Using the microplate alamar blue assay (MABA), the minimum inhibitory concentration (MIC) of shikonin against Mtb was determined to be 128 µg/mL. In order to obtain a more efficient anti-Mtb molecule, (E)-1-(6-bromo-2,3-dihydrochromen-4-ylidene)thiosemicarbazide was synthesized based on the scaffold of shikonin, which exhibited potent activity against Mtb (MIC=4 µg/mL). These results highlight that both naphthalene-1,4-dione and chroman-4-one are pharmacophores with activities against Mtb. To investigate a plausible mechanism of action, the molecular docking was firstly performed against catalase-peroxidase enzyme (KatG) of Mtb using AutoDock 4 software. The results demonstrated that both shikonin and (E)-1-(6-bromo-2,3-dihydrochromen-4-ylidene)thiosemicarbazide could bind to the active site of Mtb KatG. KatG enzyme activity and intracellular reactive oxygen species (ROS) levels in Mtb cells were then measured by ultraviolet spectrophotometric method and fluorescence microplate reader assay, respectively. The experiments confirmed that above compounds could inhibit the catalytic activity of Mtb KatG, and cause the ROS accumulation in Mtb cells. Therefore, inhibition of KatG may be a novel mechanism of action for these two compounds to fight against Mtb.


Asunto(s)
Boraginaceae , Mycobacterium tuberculosis , Humanos , Antituberculosos/farmacología , Pruebas de Sensibilidad Microbiana , Simulación del Acoplamiento Molecular , Especies Reactivas de Oxígeno
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA