Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 224
Filtrar
1.
Nat Commun ; 15(1): 1178, 2024 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-38331994

RESUMO

Unravelling biosphere feedback mechanisms is crucial for predicting the impacts of global warming. Soil priming, an effect of fresh plant-derived carbon (C) on native soil organic carbon (SOC) decomposition, is a key feedback mechanism that could release large amounts of soil C into the atmosphere. However, the impacts of climate warming on soil priming remain elusive. Here, we show that experimental warming accelerates soil priming by 12.7% in a temperate grassland. Warming alters bacterial communities, with 38% of unique active phylotypes detected under warming. The functional genes essential for soil C decomposition are also stimulated, which could be linked to priming effects. We incorporate lab-derived information into an ecosystem model showing that model parameter uncertainty can be reduced by 32-37%. Model simulations from 2010 to 2016 indicate an increase in soil C decomposition under warming, with a 9.1% rise in priming-induced CO2 emissions. If our findings can be generalized to other ecosystems over an extended period of time, soil priming could play an important role in terrestrial C cycle feedbacks and climate change.


Assuntos
Ecossistema , Pradaria , Solo , Carbono , Mudança Climática
2.
Sci China Life Sci ; 67(3): 475-487, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37219765

RESUMO

Cardiopulmonary bypass has been speculated to elicit systemic inflammation to initiate acute lung injury (ALI), including acute respiratory distress syndrome (ARDS), in patients after cardiac surgery. We previously found that post-operative patients showed an increase in endothelial cell-derived extracellular vesicles (eEVs) with components of coagulation and acute inflammatory responses. However, the mechanism underlying the onset of ALI owing to the release of eEVs after cardiopulmonary bypass, remains unclear. Plasma plasminogen-activated inhibitor-1 (PAI-1) and eEV levels were measured in patients with cardiopulmonary bypass. Endothelial cells and mice (C57BL/6, Toll-like receptor 4 knockout (TLR4-/-) and inducible nitric oxide synthase knockout (iNOS-/-)) were challenged with eEVs isolated from PAI-1-stimulated endothelial cells. Plasma PAI-1 and eEVs were remarkably enhanced after cardiopulmonary bypass. Plasma PAI-1 elevation was positively correlated with the increase in eEVs. The increase in plasma PAI-1 and eEV levels was associated with post-operative ARDS. The eEVs derived from PAI-1-stimulated endothelial cells could recognize TLR4 to stimulate a downstream signaling cascade identified as the Janus kinase 2/3 (JAK2/3)-signal transducer and activator of transcription 3 (STAT3)-interferon regulatory factor 1 (IRF-1) pathway, along with iNOS induction, and cytokine/chemokine production in vascular endothelial cells and C57BL/6 mice, ultimately contributing to ALI. ALI could be attenuated by JAK2/3 or STAT3 inhibitors (AG490 or S3I-201, respectively), and was relieved in TLR4-/- and iNOS-/- mice. eEVs activate the TLR4/JAK3/STAT3/IRF-1 signaling pathway to induce ALI/ARDS by delivering follistatin-like protein 1 (FSTL1), and FSTL1 knockdown in eEVs alleviates eEV-induced ALI/ARDS. Our data thus demonstrate that cardiopulmonary bypass may increase plasma PAI-1 levels to induce FSTL1-enriched eEVs, which target the TLR4-mediated JAK2/3/STAT3/IRF-1 signaling cascade and form a positive feedback loop, leading to ALI/ARDS after cardiac surgery. Our findings provide new insight into the molecular mechanisms and therapeutic targets for ALI/ARDS after cardiac surgery.


Assuntos
Lesão Pulmonar Aguda , Vesículas Extracelulares , Proteínas Relacionadas à Folistatina , Síndrome do Desconforto Respiratório , Animais , Humanos , Camundongos , Lesão Pulmonar Aguda/etiologia , Lesão Pulmonar Aguda/tratamento farmacológico , Lesão Pulmonar Aguda/metabolismo , Células Endoteliais/metabolismo , Vesículas Extracelulares/metabolismo , Proteínas Relacionadas à Folistatina/metabolismo , Proteínas Relacionadas à Folistatina/uso terapêutico , Inflamação/metabolismo , Lipopolissacarídeos/farmacologia , Pulmão/metabolismo , Camundongos Endogâmicos C57BL , Inibidor 1 de Ativador de Plasminogênio/metabolismo , Inibidor 1 de Ativador de Plasminogênio/uso terapêutico , Síndrome do Desconforto Respiratório/etiologia , Receptor 4 Toll-Like/metabolismo , Receptor 4 Toll-Like/uso terapêutico
3.
J Med Imaging (Bellingham) ; 10(6): 066002, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38074631

RESUMO

Purpose: The purpose of this study is to develop a freehand scan three-dimensional (3D) shear wave elasticity imaging (SWEI) method for characterizing the anisotropy of elastic properties in biological tissues. The motivation behind this work lies in addressing the limitations of traditional two-dimensional (2D) SWEI, which only measures shear wave speeds in a single direction, as well as fulfilling the clinical demand for improved medical imaging. Approach: Our imaging system utilizes a high-definition optical camera to continuously track the ultrasonic transducer, collecting spatial position-angle data of the transducer and corresponding two-dimensional SWEI data. By reconstructing three-dimensional SWEI images using these data, we achieved freehand SWEI. Results: We validated the accuracy of 2D SWEI on a standard elastic phantom, and then performed 3D SWEI on the pork tenderloin and the triceps brachii of two volunteers. We obtained shear wave speed of 1.82 to 3.12 m/s in the pork tenderloin, shear wave speed of 1.16 to 2.36 m/s in the triceps brachii of non-exercising volunteers, and shear wave speed of 0.55 to 1.63 m/s in the triceps brachii of exercising volunteers, and the maximum shear wave speed directions were generally aligned with the orientation of muscle fibers. Conclusions: We proposed a method that can overcome the limitations of 2D-SWEI regarding imaging angle while also extending the imaging angle of 3D-SWEI, which could have significant implications for improving the accuracy and safety of medical diagnoses.

5.
Dalton Trans ; 52(39): 13946-13954, 2023 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-37728124

RESUMO

The influence of the P-M-P bite angle in diphosphine ligands on selectivity has been observed in various catalytic reactions. A better understanding of the ligand bite angle concept is important for the rational design of efficient catalytic systems. In the present work, the mechanism of cobalt-catalyzed C-H functionalization of aldehydes with enynes and how the diphosphine ligands alter regioselectivity were investigated by density functional theory (DFT) calculations. The catalytic cycle is initiated by the oxidative cyclization of enynes rather than the oxidative addition of aldehydes. Regioselectivity arises from competing σ-bond metathesis and migratory insertion steps, in which the steric effects of diphosphine ligands are the dominant factors influencing the activation barriers. The calculations indicate that σ-bond metathesis is more challenging and its feasibility is highly dependent on the ligand bite angle. The improved mechanistic understanding will enable further design of transition-metal-catalyzed selective cyclization reactions.

6.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 31(4): 1093-1099, 2023 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-37551482

RESUMO

OBJECTIVE: To investigate the effect of resveratrol (RSV) on the proliferation of multiple myeloma (MM) cells and its molecular mechanism. METHODS: MM cells (MM1.S, RPMI-8226 and U266) were treated with different concentrations of RSV for 24-72 h. The effect of RSV on the proliferation of MM cells was detected by CCK-8 (cell counting kit-8) assay. RPMI-8226 cells were divided into RSV, miR-21 mimic, RSV+miR-21 mimic, miR-21 inhibitor and RSV+miR-21 inhibitor groups, and transfected with corresponding plasmids. The cell cycle distribution of each group was detected by flow cytometry with propidium iodide (PI) single staining. The cell apoptosis of each group was detected by AnnexinV-FITC/PE-PI double staining. The expression of miR-21 in MM cells treated with RSV and the expression of KLF5 mRNA in each group were detected by qRT-PCR. The expression of KLF5 protein in each group was detected by Western blot. RESULTS: RSV inhibited the proliferation and induced apoptosis of MM cells in a time- and dose-dependent manner. After the MM cells were treated with RSV, the number of cells in sub-G1 phase was increased, and that in G2/M phase was decreased. Moreover, RSV significantly downregulated the expression of miR-21 in MM cells, and the inhibitory effect of miR-21 mimic on KLF5 expression in MM cells was counteracted by RSV. CONCLUSION: RSV may inhibit the proliferation and induce apoptosis of MM cells by inhibiting miR-21 and up-regulating KLF5 expression.


Assuntos
MicroRNAs , Mieloma Múltiplo , Humanos , Resveratrol/farmacologia , Mieloma Múltiplo/metabolismo , Proliferação de Células , Linhagem Celular Tumoral , Apoptose , MicroRNAs/genética
9.
Anal Methods ; 15(23): 2861-2867, 2023 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-37264865

RESUMO

Sulfur mustard (SM) is an important chemical warfare agent (CWA) and has been used frequently in various conflicts. It is important to develop a facile, rapid, sensitive and selective detection method for SM. In this work, we constructed a novel fluorescent probe PCS capable of generating active sensing species for rapid and selective detection of SM and its simulant CEES (2-chloroethyl ethyl sulfide). PCS exhibits excellent chemical and photostability and can generate reactive species in situ for rapid (within 90 s, at 60 °C) and selective detection of SM and CEES in solution with high sensitivity (∼nM level). Moreover, PCS could enable the detection of mustards in situ. A test strip with PCS and KOH was prepared and realized the sensitive and selective detection of CEES in the gas phase. In addition, the PCS probe can realize facile and rapid detection of CEES-contaminated surfaces by spraying its sensing system (ethanol solution containing PCS and KOH). The sensing mechanism was well demonstrated through the separation and characterization of the sensing product.


Assuntos
Substâncias para a Guerra Química , Gás de Mostarda , Gás de Mostarda/análise , Gás de Mostarda/química , Corantes Fluorescentes , Substâncias para a Guerra Química/análise
10.
Am J Trop Med Hyg ; 109(1): 101-104, 2023 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-37188347

RESUMO

Hemorrhagic fever with renal syndrome (HFRS), a natural epidemic disease caused by hantavirus (HV), is one of the viral diseases that pose a major threat to our health. Considering the increasing number of atypical-onset cases reported in some countries, it is important to be familiar with the symptoms of HFRS and the signs of HV infection. This report describes the case of a 55-year-old man with complaints of fever, vomiting, and diarrhea. His symptoms showed no significant improvement after routine anti-infective, antipyretic, and other symptomatic supportive treatments administered at a local clinic. During these treatments, the patient had progressive oliguria; after 3 days, he also developed multiple organ failures, such as the liver and kidney, and was examined for positive serum IgM antibodies to hemorrhagic fever during treatment at our hospital. The patient was finally diagnosed with HFRS followed by multiple organ failure. After antiviral therapy, including ribavirin, piperacillin, and tazobactam, continuous renal replacement therapy, fluid metabolism adjustment, and related supportive therapy were administered, which improved his liver and kidney function. He was discharged on the 25th day after hospitalization. It is difficult to manage patients who develop multiple organ failure after HFRS. Moreover, this condition is rare in clinical settings, with fever being the initial indication. For diseases with unknown origin such as refractory fever and diarrhea, it is crucial to differentiate them from common pathogenic infection and HV infections to provide timely treatment that improves the prognosis of patients.


Assuntos
Febre Hemorrágica com Síndrome Renal , Orthohantavírus , Masculino , Humanos , Pessoa de Meia-Idade , Febre Hemorrágica com Síndrome Renal/complicações , Febre Hemorrágica com Síndrome Renal/diagnóstico , Febre Hemorrágica com Síndrome Renal/epidemiologia , Insuficiência de Múltiplos Órgãos/etiologia , Rim , Febre/complicações , Diarreia/complicações
11.
Trop Doct ; 53(2): 307-308, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36872880

RESUMO

Though common, the extraction of rectal foreign bodies is still a great challenge for surgeons. The foreign body's position can usually be verified by plain abdominal radiography. Given the potential of sexually transmitted disease, screening for HIV, hepatitis, and syphilis is warranted prior to intervention. The utilization and selection of surgical instruments need to be flexible, ingenious, and innovative.


Assuntos
Corpos Estranhos , Reto , Humanos , Reto/diagnóstico por imagem , Reto/cirurgia , Zea mays , Corpos Estranhos/diagnóstico por imagem , Corpos Estranhos/cirurgia
12.
Chem Sci ; 14(12): 3352-3362, 2023 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-36970104

RESUMO

Migratory insertions of alkenes into metal-carbon (M-C) bonds are elementary steps in diverse catalytic processes. In the present work, a radical-type migratory insertion that involves concerted but asynchronous M-C homolysis and radical attack was revealed by computations. Inspired by the radical nature of the proposed migratory insertion, a distinct cobalt-catalyzed radical-mediated carbon-carbon (C-C) cleavage mechanism was proposed for alkylidenecyclopropanes (ACPs). This unique C-C activation is key to rationalizing the experimentally observed selectivity for the coupling between benzamides and ACPs. Furthermore, the C(sp2)-H activation in the coupling reaction occurs via the proton-coupled electron transfer (PCET) mechanism rather than the originally proposed concerted metalation-deprotonation (CMD) pathway. The ring opening strategy may stimulate further development and discovery of novel radical transformations.

13.
ISME J ; 17(4): 611-619, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36732614

RESUMO

Study of life history strategies may help predict the performance of microorganisms in nature by organizing the complexity of microbial communities into groups of organisms with similar strategies. Here, we tested the extent that one common application of life history theory, the copiotroph-oligotroph framework, could predict the relative population growth rate of bacterial taxa in soils from four different ecosystems. We measured the change of in situ relative growth rate to added glucose and ammonium using both 18O-H2O and 13C quantitative stable isotope probing to test whether bacterial taxa sorted into copiotrophic and oligotrophic groups. We saw considerable overlap in nutrient responses across most bacteria regardless of phyla, with many taxa growing slowly and few taxa that grew quickly. To define plausible life history boundaries based on in situ relative growth rates, we applied Gaussian mixture models to organisms' joint 18O-13C signatures and found that across experimental replicates, few taxa could consistently be assigned as copiotrophs, despite their potential for fast growth. When life history classifications were assigned based on average relative growth rate at varying taxonomic levels, finer resolutions (e.g., genus level) were significantly more effective in capturing changes in nutrient response than broad taxonomic resolution (e.g., phylum level). Our results demonstrate the difficulty in generalizing bacterial life history strategies to broad lineages, and even to single organisms across a range of soils and experimental conditions. We conclude that there is a continued need for the direct measurement of microbial communities in soil to advance ecologically realistic frameworks.


Assuntos
Traços de História de Vida , Solo , Ecossistema , Microbiologia do Solo , Bactérias
14.
Colloids Surf B Biointerfaces ; 223: 113158, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36731268

RESUMO

Gd3+-doped quantum dots (QDs) have been widely used as small-sized bifunctional contrast agents for fluorescence/magnetic resonance (FL/MR) dual-modality imaging. However, Gd3+ doping will always compromise the FL of host QDs. Therefore, balancing the Gd3+ doping and the optical properties of QDs is crucial for constructing high-performance bifunctional nanoprobes. Additionally, most paramagnetic QDs are synthesized in the organic phase and need to be transferred to the aqueous phase for bioimaging. Herein, ingeniously designed shell-doped Cu-In-S/ZnS:Gd3+ QDs have been prepared in the aqueous phase. It has been demonstrated that isolating paramagnetic Gd3+ from fluorescent Cu-In-S core via doping Gd3+ into ZnS shell not only avoided the decrease of FL quantum yield (QY), but also ensured the water accessibility of paramagnetic Gd3+ ions, by which the FL QY and r1 relaxivity of Cu-In-S/ZnS:Gd3+ QDs achieved as much as 15.6% and 15.33 mM-1·s-1, respectively. These high-performance QDs with excellent stability, low biotoxicity, and good tumor permeability were successfully applied for in vivo tumor FL/MR dual-modality imaging, and have shown significant potential in the precision detection and diagnosis of diseases.


Assuntos
Neoplasias , Pontos Quânticos , Humanos , Sulfetos , Compostos de Zinco , Neoplasias/patologia , Água
15.
Oecologia ; 201(3): 771-782, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36847885

RESUMO

Density dependence in an ecological community has been observed in many macro-organismal ecosystems and is hypothesized to maintain biodiversity but is poorly understood in microbial ecosystems. Here, we analyze data from an experiment using quantitative stable isotope probing (qSIP) to estimate per-capita growth and mortality rates of bacterial populations in soils from several ecosystems along an elevation gradient which were subject to nutrient addition of either carbon alone (glucose; C) or carbon with nitrogen (glucose + ammonium-sulfate; C + N). Across all ecosystems, we found that higher population densities, quantified by the abundance of genomes per gram of soil, had lower per-capita growth rates in C + N-amended soils. Similarly, bacterial mortality rates in C + N-amended soils increased at a significantly higher rate with increasing population size than mortality rates in control and C-amended soils. In contrast to the hypothesis that density dependence would promote or maintain diversity, we observed significantly lower bacterial diversity in soils with stronger negative density-dependent growth. Here, density dependence was significantly but weakly responsive to nutrients and was not associated with higher bacterial diversity.


Assuntos
Ecossistema , Solo , Microbiologia do Solo , Bactérias , Carbono
16.
Anal Chem ; 95(2): 1755-1763, 2023 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-36596643

RESUMO

Mustard gas [sulfur mustard (SM)] and phosgene are the most frequently used chemical warfare agents (CWAs), which pose a serious threat to human health and national security, and their rapid and accurate detection is essential to respond to terrorist attacks and industrial accidents. Herein, we developed a fluorescent probe with o-hydroxythioketone as two sensing sites, AQso, which can detect and distinguish mustard gas and phosgene. The dual-sensing-site probe AQso reacts with mustard gas to form a cyclic product with high sensitivity [limit of detection (LOD) = 70 nM] and is highly selective to SM over phosgene, SM analogues, active alkylhalides, acylhalides, and nerve agent mimics, in ethanol solutions. When encountering phosgene, AQso rapidly converts to cyclic carbonate, which is sensitive (LOD = 14 nM) and highly selective. Their sensing mechanisms of AQso to mustard gas and phosgene were well demonstrated by separation and characterization of the sensing products. Furthermore, a facile test strip with the probe was prepared to distinguish 2-chloroethyl ethyl sulfide (CEES) and phosgene in the gas phase by different fluorescence colors and response rates. Not using the complicated instrument, the qualitative and quantitative detection of CEES or phosgene can be achieved only by measuring the red-green-blue (RGB) channel intensity of the test strip after being exposed to CEES or phosgene gas by the smartphone with an RGB color application.


Assuntos
Substâncias para a Guerra Química , Gás de Mostarda , Fosgênio , Humanos , Fosgênio/química , Corantes Fluorescentes/química
18.
Ear Nose Throat J ; 102(4): 223-226, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33729894

RESUMO

An oncologic defect that includes both the lower eyelid and the infraorbital cheek often results in complex reconstructive problems because its reconstruction involves 2 distinct tissue types and cosmetic subunits. Herein, we first present a novel combination of modified supratrochlear artery forehead island flap and advancement rotation cheek flap enables reconstructing a large oncologic defect of lower eyelid and infraorbital cheek. Although discoid lupus erythematosus affects the skin, the patient had achieved a satisfying color match and an acceptable aesthetic restoration without tumor recurrence. This novel flap has shown to be feasible, reliable, and advantageous alternative to the repair of such defects.


Assuntos
Procedimentos de Cirurgia Plástica , Neoplasias Cutâneas , Humanos , Bochecha/cirurgia , Recidiva Local de Neoplasia/cirurgia , Retalhos Cirúrgicos , Pálpebras/cirurgia , Neoplasias Cutâneas/cirurgia
19.
Genomics ; 115(1): 110540, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36563917

RESUMO

Non-coding RNAs (ncRNAs) induced competing endogenous RNAs (ceRNA) play crucial roles in various biological process by regulating target gene expression. However, the studies of ceRNA networks in the regulation of ovarian ovulation processing of chicken remains deficient compared to that in mammals. Our present study revealed that circEML1 was differential expressed in hen's ovarian tissues at different ages (15 W/20 W/30 W/68 W) and identified as a loop structure from EML1 pre-mRNA, which promoted the expressions of CYP19A1/StAR and E2/P4 secretion in follicular granulosa cells (GCs). Furthermore, circEML1 could serve as a sponge of gga-miR-449a and also found that IGF2BP3 was targeted by gga-miR-449a to co-participate in the steroidogenesis, which possibly act the regulatory role via mTOR/p38MAPK pathways. Meanwhile, in the rescue experiment, gga-miR-449a could reverse the promoting role of circEML1 to IGF2BP3 and steroidogenesis. Eventually, this study suggested that circEML1/gga-miR-449a/IGF2BP3 axis exerted an important role in the steroidogenesis in GCs of chicken.


Assuntos
Galinhas , MicroRNAs , Animais , Feminino , Galinhas/genética , Galinhas/metabolismo , Células da Granulosa , Mamíferos/genética , MicroRNAs/genética , MicroRNAs/metabolismo , Ovário/metabolismo , Esteroides/metabolismo , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/metabolismo
20.
J Control Release ; 353: 186-195, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36403684

RESUMO

The drug efflux by P-glycoprotein (P-gp) is the primary contributor of multidrug resistance (MDR), which eventually generates insufficient nuclear drug accumulation and chemotherapy failure. In this paper, reversible covalent nanoassemblies on the basis of catechol-functionalized methoxy poly (ethylene glycol) (mPEG-dop) and phenylboronic acid-modified cholesterol (Chol-PBA) are successfully synthesized for delivery of both doxorubicin (DOX, anti-cancer drug) and tariquidar (TQR, P-glycoprotein inhibitor), which shows efficient nuclear DOX accumulation for overcoming tumor MDR. Through naturally forming phenylboronate linkage in physiological circumstances, Chol-PBA is able to bond with mPEG-dop. The resulting conjugates (PC) could self-assemble into reversible covalent nanoassemblies by dialysis method, and transmission electron microscopy analysis reveals the PC distributes in nano-scaled spherical particles before and after drug encapsulation. Under the assistance of Chol, PC can enter into lysosome of tumor cells via low-density lipoprotein (LDL) receptor-mediated endocytosis. Then the loaded TQR and DOX are released in acidic lysosomal compartments, which inhibit P-gp mediated efflux and elevate nuclear accumulation of DOX, respectively. At last, this drug loaded PC nanoassemblies show significant tumor suppression efficacy in multidrug-resistant tumor models, which suggests great potential for addressing MDR in cancer therapy.


Assuntos
Antineoplásicos , Nanopartículas , Neoplasias , Humanos , Resistencia a Medicamentos Antineoplásicos , Doxorrubicina , Membro 1 da Subfamília B de Cassetes de Ligação de ATP , Neoplasias/tratamento farmacológico , Portadores de Fármacos/química , Subfamília B de Transportador de Cassetes de Ligação de ATP , Linhagem Celular Tumoral , Células MCF-7
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...