Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 152
Filtrar
Más filtros

País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Nano Lett ; 24(22): 6683-6688, 2024 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-38767925

RESUMEN

Two-dimensional (2D) ferroelectrics promise ultrathin flexible nanoelectronics, typically utilizing a metal-ferroelectric-metal sandwich structure. Electrodes can either contribute free carriers to screen the depolarization field, enhancing nanoscale ferroelectricity, or induce charge doping, disrupting the long-range crystalline order. We explore electrodes' dual roles in 2D ferroelectric capacitors, supported by first-principles calculations covering a range of electrode work functions. Our results reveal volcano-type relationships between ferroelectric-electrode binding affinity and work function, which are further unified by a quadratic scaling between the binding energy and the transferred interfacial charge. At the monolayer limit, charge transfer dictates the ferroelectric stability and switching properties. This general characteristic is confirmed in various 2D ferroelectrics including α-In2Se3, CuInP2S6, and SnTe. As the ferroelectric layer's thickness increases, the capacitor stability evolves from a charge-transfer-dominated state to a screening-dominated state. The delicate interplay between these two effects has important implications for 2D ferroelectric capacitor applications.

2.
Opt Express ; 32(6): 9995-10004, 2024 Mar 11.
Artículo en Inglés | MEDLINE | ID: mdl-38571222

RESUMEN

We present a design of middle-infrared modulation absorbers based on vanadium dioxide (VO2). By using the electron beam evaporation technique, the Ag/SiO2/VO2/Ag/VO2 multilayer structure can achieve double band strong absorption in the mid-infrared, and dynamically adjust the absorption performance through VO2. The simulation results demonstrate a remarkable absorption rate of 91.8% and 98.9% at 9.09 µm and 10.25 µm, respectively. The high absorption is elucidated by analyzing the field strength distribution in each layer. Meanwhile, based on the phase change characteristics of VO2, the absorber has exceptional thermal regulation, with a remarkable 78% heat regulation range in the mid-infrared band. The size altering of the absorbing layer is effective in enhancing and optimizing the structure's absorption performance. The structure is used to characterize probe molecules of CV and R6 G by mid-infrared spectroscopy, which illustrates an impressive limit of detection (LOD) of 10-7 M for both substances. These results provide valuable insights for designing future high-performance tunable optical devices.

3.
Environ Res ; 252(Pt 2): 118960, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38636648

RESUMEN

Conventional plastics are inherently difficult to degrade, causing serious plastic pollution. With the development of society, biodegradable plastics (BPs) are considered as an alternative to traditional plastics. However, current research indicated that BPs do not undergo complete degradation in natural environments. Instead, they may convert into biodegradable microplastics (BMPs) at an accelerated rate, thereby posing a significant threat to environment. In this paper, the definition, application, distribution, degradation behaviors, bioaccumulation and biomagnification of BPs were reviewed. And the impacts of BMPs on soil and marine ecosystems, in terms of physicochemical property, nutrient cycling, microorganisms, plants and animals were comprehensively summarized. The effects of combined exposure of BMPs with other pollutants, and the mechanism of ecotoxicity induced by BMPs were also addressed. It was found that BMPs reduced pH, increased DOC content, and disrupted the nitrification of nitrogen cycle in soil ecosystem. The shoot dry weight, pod number and root growth of soil plants, and reproduction and body length of soil animals were inhibited by BMPs. Furthermore, the growth of marine plants, and locomotion, body length and survival of marine animals were suppressed by BMPs. Additionally, the ecotoxicity of combined exposure of BMPs with other pollutants has not been uniformly concluded. Exposure to BMPs induced several types of toxicity, including neurotoxicity, gastrointestinal toxicity, reproductive toxicity, immunotoxicity and genotoxicity. The future calls for heightened attention towards the regulation of the degradation of BPs in the environment, and pursuit of interventions aimed at mitigating their ecotoxicity and potential health risks to human.


Asunto(s)
Microplásticos , Microplásticos/toxicidad , Animales , Contaminantes del Suelo/toxicidad , Plásticos Biodegradables/toxicidad , Océanos y Mares , Contaminantes Químicos del Agua/toxicidad , Organismos Acuáticos/efectos de los fármacos , Suelo/química , Ecosistema
4.
Molecules ; 29(12)2024 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-38930916

RESUMEN

With the growing significance of green chemistry in organic synthesis, electrochemical oxidation has seen rapid development. Compounds undergo oxidation-reduction reactions through electron transfer at the electrode surface. This article proposes the use of electrochemical methods to achieve cleavage of the benzyl C-N bond. This method selectively oxidatively cleaves the C-N bond without the need for metal catalysts or external oxidants. Additionally, primary, secondary, and tertiary amines exhibit good adaptability under these conditions, utilizing water as the sole source of oxygen.

5.
J Am Chem Soc ; 145(11): 6257-6269, 2023 Mar 22.
Artículo en Inglés | MEDLINE | ID: mdl-36893341

RESUMEN

Redox intercalation involves coupled ion-electron motion within host materials, finding extensive application in energy storage, electrocatalysis, sensing, and optoelectronics. Monodisperse MOF nanocrystals, compared to their bulk phases, exhibit accelerated mass transport kinetics that promote redox intercalation inside nanoconfined pores. However, nanosizing MOFs significantly increases their external surface-to-volume ratios, making the intercalation redox chemistry into MOF nanocrystals difficult to understand due to the challenge of differentiating redox sites at the exterior of MOF particles from the internal nanoconfined pores. Here, we report that Fe(1,2,3-triazolate)2 possesses an intercalation-based redox process shifted ca. 1.2 V from redox at the particle surface. Such distinct chemical environments do not appear in idealized MOF crystal structures but become magnified in MOF nanoparticles. Quartz crystal microbalance and time-of-flight secondary ion mass spectrometry combined with electrochemical studies identify the existence of a distinct and highly reversible Fe2+/Fe3+ redox event occurring within the MOF interior. Systematic manipulation of experimental parameters (e.g., film thickness, electrolyte species, solvent, and reaction temperature) reveals that this feature arises from the nanoconfined (4.54 Å) pores gating the entry of charge-compensating anions. Due to the requirement for full desolvation and reorganization of electrolyte outside the MOF particle, the anion-coupled oxidation of internal Fe2+ sites involves a giant redox entropy change (i.e., 164 J K-1 mol-1). Taken together, this study establishes a microscopic picture of ion-intercalation redox chemistry in nanoconfined environments and demonstrates the synthetic possibility of tuning electrode potentials by over a volt, with profound implications for energy capture and storage technologies.

6.
J Org Chem ; 88(5): 3054-3067, 2023 Mar 03.
Artículo en Inglés | MEDLINE | ID: mdl-36797219

RESUMEN

A three-component oxychalcogenation reaction, from alkenes, diselenides/thiophenols, and H2O/alcohols, has been realized herein. Tetrabutylammonium tribromide (TBATB) and dimethylsulfoxide (DMSO) are utilized as the catalyst and the terminal oxidant, respectively, to enable this difunctionalization transformation. The metal-free reaction system shows good functional group compatibility, providing a unified and practical approach to access ß-hydroxyl or ß-alkoxy organochalcogenides.

7.
Nano Lett ; 22(23): 9493-9499, 2022 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-36382908

RESUMEN

Semiconductor photocatalyst particles convert solar energy to fuels like H2. The particles are often assumed to provide crystalline-facet-dependent electron-hole separation. A common strategy is to deposit a hydrogen evolution reaction (HER) electrocatalyst on electron-selective facets and an oxygen evolution reaction (OER) electrocatalyst on hole-selective facets. A precise understanding of how charge-carrier-selective contacts emerge and how they are rationally designed, however, is missing. Using a combination of ex situ and in situ conducting atomic force microscopy (AFM) experiments and new ionomer/catalyst-semiconductor test structures, we show how heterogeneity in charge-carrier selectivity can be measured at the nanoscale. We discover that the presence of the water/electrolyte interface is critical to induce hole selectivity between the CoOx water-oxidation catalyst and the BiVO4 light absorber. pH-dependent measurements suggest that negative surface charge on the semiconductor is central to inducing hole selectivity. The work also demonstrates a new approach to control local pH and introduce water using thin-film ionomers compatible with conductive AFM measurements.

8.
Environ Geochem Health ; 45(6): 2803-2838, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-36598611

RESUMEN

Microplastics (MPs) have become increasingly serious global problems due to their wide distribution and complicated impacts on living organisms. To obtain a comprehensive overview of the latest research progress on MPs, we conducted a bibliometric analysis combined with a literature review. The results showed that the number of studies on MPs has grown exponentially since 2010. Recently, the hotspot on MPs has shifted to terrestrial ecosystems and biological health risks, including human health risks. In addition, the toxic effects, identification and quantification of MPs are relatively new research hotspots. We subsequently provide a review of MPs studies related to health risks to terrestrial higher mammals and, in particular, to humans, including detection methods and potential toxicities based on current studies. Currently, MPs have been found existing in human feces, blood, colon, placenta and lung, but it is still unclear whether this is associated with related systemic diseases. In vivo and in vitro studies have demonstrated that MPs cause intestinal toxicity, metabolic disruption, reproductive toxicity, neurotoxicity, immunotoxicity through oxidative stress, apoptosis and specific pathways, etc. Notably, in terms of combined effects with pollutants and neurotoxicity, the effects of MPs are still controversial. Future attention should be paid to the detection and quantification of MPs in human tissues, exploring the combined effects and related mechanisms of MPs with other pollutants and clarifying the association between MPs and the development of pre-existing diseases. Our work enhances further understanding of the potential health risks of MPs to terrestrial higher mammals.


Asunto(s)
Contaminantes Ambientales , Contaminantes Químicos del Agua , Animales , Humanos , Microplásticos/toxicidad , Plásticos , Ecosistema , Contaminantes Ambientales/análisis , Bibliometría , Contaminantes Químicos del Agua/análisis , Mamíferos
9.
Actas Esp Psiquiatr ; 51(6): 271-280, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-38321722

RESUMEN

BACKGROUND: The chronic course and recurring acute episodes of rheumatoid arthritis (RA) can significantly affect the psychological and mental health of patients. This study aimed to investigate the prevalence of depression in Chinese patients with rheumatoid arthritis (RA) through a systematic review and meta-analysis. METHODS: We conducted a comprehensive literature search on electronic databases from the inception of the database to April 2023. The inclusion criteria included cross-sectional or case-control studies on depression prevalence with a sample size of at least 50 participants. The data was extracted from the included studies and analyzed to calculate the pooled depression prevalence, along with a 95% confidence interval (CI), using Review Manager 5.3 software (Version 5.3. Copenhagen: The Nordic Cochrane Centre, The Cochrane Collaboration, 2014). RESULTS: Thirteen studies (n = 29,113) were included, with females accounting for over 50% of all participants. Based on the data pooled from all 13 studies, the observed depression prevalence in Chinese individuals with RA was 37% (95% CI: 28-46%; I2 = 95%; p < 0.0001). A subsequent subgroup analysis was conducted on scale types, age, and gender. Regarding scale types, the depression prevalence was assessed using various scales included the Hospital Anxiety and Depression Scale (HAMD), Hamilton Depression Scale (HADS), Center for Epidemiologic Studies Depression (CES-D) scale, Diagnostic and Statistical Manual of Mental Disorder (fourth edition DSM.IV) diagnostic criteria, and Self-rating Depression Scale (SDS) were 50%, 35%, 58%, 39%, and 41%, respectively. Based on mean age, five studies researched RA individuals <50 years old, establishing a depression prevalence of 48% (95% CI: 32-65%). In contrast, eight studies researched RA individuals ≥50 years old, establishing a depression prevalence of 41% (95% CI: 32-51%). Gender-based analysis indicated a depression prevalence in female RA individuals of 45% (95% CI: 37-55%) and 39% (95% CI: 29-48%) among male RA patients. Depression prevalence established significant correlations with specific scales, including the HAMD scale (odds ratio (OR) 4.93, 95% CI: 1.79-10.2), CES-D scale (OR 2.83, 95% CI: 1.71-4.65), DSM.IV criteria (OR 0.75, 95% CI: 0.38-1.51), and SDS (OR 0.95, 95% CI: 0.32-2.16). Additionally, depression prevalence was associated with age categories (age ≥50: OR 1.25, 95% CI: 0.59-2.70; age <50: OR 1.99, 95% CI: 0.93-3.81), as well as gender (female: OR 1.63, 95% CI: 0.64-4.57; male: OR 1.07, 95% CI: 0.38-3.03), although some associations did not reach statistical significance. CONCLUSION: The depression prevalence was high in Chinese individuals with RA, especially in females and patients under 50 years old. These findings suggest the need for improving detection and management of depression in RA patients.


Asunto(s)
Artritis Reumatoide , Depresión , Humanos , Artritis Reumatoide/epidemiología , Artritis Reumatoide/psicología , China , Estudios Transversales , Depresión/epidemiología , Prevalencia
10.
Opt Express ; 30(11): 17967-17979, 2022 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-36221607

RESUMEN

This work systematically investigates the third-order nonlinear optical (NLO) properties and ultrafast carrier dynamics of layered indium selenide (InSe) obtained by mechanical exfoliation (ME). The two-photon absorption (TPA) effect of layered InSe was tested using micro-Z/I-scan techniques. The results indicate that InSe flakes undergo the TPA response under the excitation of both 520 nm and 1040 nm fs pulses, and that InSe is more likely to achieve TPA saturation under visible light excitation. Furthermore, ultrafast carrier dynamics revealed that InSe flakes in the visible region undergo a transition from photoinduced absorption to photobleaching and exhibit a fast recombination time of ∼0.4-1ps, suggesting a high optical modulation speed as high as ∼1-2.5 THz.

11.
J Org Chem ; 87(16): 10684-10697, 2022 Aug 19.
Artículo en Inglés | MEDLINE | ID: mdl-35939820

RESUMEN

A tetrabutylammonium tribromide-mediated three-component reaction of alkenes, diselenides, and sulfoximines has been established herein, providing direct and metal-free access to diverse ß-arylseleno sulfoximine derivatives. This regioselective sulfoximido-selenization protocol proceeds efficiently under mild and ambient conditions with generally good yields. This strategy is featured by step and atom economy, practicability, a broad substrate scope, and gram-scale synthesis.

12.
Environ Res ; 213: 113716, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-35718165

RESUMEN

Understanding of mechanisms in nitrous oxide (N2O) emission from constructed wetland (CW) is particularly important for the establishment of related strategies to reduce greenhouse gas (GHG) production during its wastewater treatment. However, plant biomass accumulation, microbial communities and nitrogen transformation genes distribution and their effects on N2O emission from CW as affected by different nitrogen forms in aquatic environment have not been reported. This study investigated the interactive effects of aquatic nitrogen and plant biomass on N2O emission from subsurface CW with NH4+-N (CW-A) or NO3--N (CW-B) wastewater. The experimental results show that NH4+-N and NO3--N removal efficiencies from CW mesocosms were 49.4% and 87.6%, which indirectly lead to N2O emission fluxes of CW-A and CW-B maintained at 213 ± 67 and 462 ± 71 µg-N/(m2·h), respectively. Correlation analysis of nitrogen conversion dynamic indicated that NO2--N accumulation closely related to N2O emission from CW. Aquatic NH4+-N could up-regulate plant biomass accumulation by intensifying citric acid cycle, glycine-serine-threonine metabolism etc., resulting in more nitrogen uptake and lower N2O emission/total nitrogen (TN) removal ratio of CW-A compared to CW-B. Although the abundance of denitrifying bacteria and N2O reductase nosZ in CW-B were significantly higher than that of CW-A, after fed with mixed NH4+-N and NO3--N influent, N2O fluxes and N2O emission/TN removal ratio in CW-A were extremely close to that of CW-B, suggesting that nitrogen form rather than nitrogen transformation microbial communities and N2O reductase nosZ determines N2O emission from CW. Hence, the selection of nitrate-loving plants will play an important role in inhibiting N2O emission from CW.


Asunto(s)
Óxido Nitroso , Humedales , Biomasa , Desnitrificación , Nitrógeno/metabolismo , Oxidorreductasas/metabolismo , Plantas/metabolismo
13.
Opt Express ; 29(5): 7398-7409, 2021 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-33726241

RESUMEN

The transmissive optical fiber localized surface plasmon resonance (LSPR) sensor has become an effective tool in refractive index sensing because of its compact structure, high sensitivity and strong designability. However, its special structure with the sensing region in the middle of the optical fiber leads to the shortcomings of difficult preparation and poor reproducibility, which greatly restricts its application scopes. In order to solve such problem, we design gold nanoparticle (AuNP)-based fusion spliced transmissive optical fiber LSPR probes, which are fabricated via the fusion splicing between the surface modified combination tapered optical fiber and another multimode quartz optical fiber but are totally different from other fabrications of the reported transmissive optical fiber LSPR probes. The fiber probe fabrication is rather simple and cost-effective, only relying on the procedures of combination tapered optical fiber preparation, surface modification and probe fusion splicing, and except for the probe fusion splicing, the other procedures can be mass prepared thus maintaining high efficiency and good reproducibility in fiber probe fabrications. Moreover, according to the experimental verifications, the proposed fiber probes can reach rather high sensitivity in refractive index sensing with high accuracy and good stability in both static and dynamic detecting modes. Therefore, the AuNP-based fusion spliced transmissive optical fiber LSPR probe is a preferred solution for refractive index sensing and can be widely used in various applications.

14.
Calcif Tissue Int ; 108(3): 281-287, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33068140

RESUMEN

Previous observational studies have identified various risk factors associated with the development of osteoporosis, including sex hormone-binding globulin (SHBG). The aim of this study was to determine the potential causal effects of circulating SHBG concentrations on bone mineral density (BMD). Two-sample Mendelian randomization (MR) approach was applied in analyses. From summary-level data of genome-wide association studies (GWAS), we selected 11 single-nucleotide polymorphisms (SNPs) associated with SHBG levels as instrumental variable, and used summary statistics for BMD at forearm (FA) (n = 8143), femoral neck (FN) (n = 32,735), lumbar spine (LS) (n = 28,498) and heel (HL) (n = 394,929), and total-body BMD of different age-stages (15 or less, 15-30, 30-45, 45-60, 60 or more years old) (n = 67,358). Inverse causal associations was observed between SHBG levels and FA BMD (Effect = - 0.26; 95% CI - 0.49 to - 0.04; P = 0.022), HL eBMD (Effect = - 0.09; 95% CI - 0.12 to - 0.06; P = 3.19 × 10-9), and total-body BMD in people aged 45-60 years (Effect = - 0.16; 95% CI - 0.31 to - 2.4 × 10-3; P = 0.047) and over 60 years (Effect = - 0.19; 95% CI - 0.33 to - 0.05; P = 0.006). Our study demonstrates that circulating SHBG concentrations are inversely associated with FA and HL eBMD, and total-body BMD in people aged over 45 years, suggesting that the role of SHBG in the development of osteoporosis might be affected by chronological age of patients and skeletal sites.


Asunto(s)
Densidad Ósea , Globulina de Unión a Hormona Sexual , Adolescente , Adulto , Cuello Femoral , Estudio de Asociación del Genoma Completo , Humanos , Análisis de la Aleatorización Mendeliana , Persona de Mediana Edad , Osteoporosis/genética , Polimorfismo de Nucleótido Simple , Globulina de Unión a Hormona Sexual/análisis , Adulto Joven
15.
J Biochem Mol Toxicol ; 35(3): e22669, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33274826

RESUMEN

The kidney is the target of the acute toxicity of depleted uranium (DU). However, the mechanism of DU-induced cytotoxicity is not clear. The study was to demonstrate the role of autophagy in DU-induced cytotoxicity and to determine the potential mechanism. We confirmed that after a 4-h exposure to DU, the autophagic vacuoles and the autophagy marker light chain 3-II in the human embryonic kidney 293 cells (HEK293) increased, and cytotoxicity decreased by abrogation of excessive autophagy using autophagy inhibitor. We also found activation of nucleus p53 and inhibiting mTOR pathways in DU-treated HEK293 cells. Meanwhile, ethylmalonic encephalopathy 1 (ETHE1) decreased as the exposure dose of DU increased, with increasing autophagy flux. We suggested that by reducing ETHE1, activation of the p53 pathway, and inhibiting mTOR pathways, DU might induce overactive autophagy, which affected the cytotoxicity. This study will provide a novel therapeutic target for the treatment of DU-induced cytotoxicity.


Asunto(s)
Autofagia/efectos de los fármacos , Citotoxinas/toxicidad , Proteínas Mitocondriales/metabolismo , Proteínas de Transporte Nucleocitoplasmático/metabolismo , Uranio/toxicidad , Células HEK293 , Humanos
16.
Arch Toxicol ; 95(2): 693-701, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-33084937

RESUMEN

Formaldehyde (FA), an economically important and ubiquitous chemical, has been classified as a human carcinogen and myeloid leukemogen. However, the underlying mechanisms of leukemogenesis remain unclear. Unlike many classical leukemogens that damage hematopoietic stem/progenitor cells (HSC/HPC) directly in the bone marrow, FA-as the smallest, most reactive aldehyde-is thought to be incapable of reaching the bone marrow through inhalation exposure. A recent breakthrough study discovered that mouse lung contains functional HSC/HPC that can produce blood cells and travel bi-directionally between the lung and bone marrow, while another early study reported the presence of HSC/HPC in rat nose. Based on these findings, we hypothesized that FA inhalation could induce toxicity in HSC/HPC present in mouse lung and/or nose rather than in the bone marrow. To test this hypothesis, we adapted a commercially available protocol for culturing burst-forming unit-erythroid (BFU-E) and colony-forming unit-granulocyte, macrophage (CFU-GM) colonies from bone marrow and spleen to also enable culture of these colonies from mouse lung and nose, a novel application of this assay. We reported that in vivo exposure to FA at 3 mg/m3 or ex vivo exposure up to 400 µM FA decreased the formation of both colony types from mouse lung and nose as well as from bone marrow and spleen. These findings, to the best of our knowledge, are the first empirically to show that FA exposure can damage mouse pulmonary and olfactory HSC/HPC and provide potential biological plausibility for the induction of leukemia at the sites of entry rather than the bone marrow.


Asunto(s)
Formaldehído/toxicidad , Células Madre Hematopoyéticas/efectos de los fármacos , Pulmón/efectos de los fármacos , Nariz/efectos de los fármacos , Animales , Células de la Médula Ósea/efectos de los fármacos , Carcinógenos/toxicidad , Células Cultivadas , Exposición por Inhalación , Leucemia/inducido químicamente , Masculino , Ratones , Ratones Endogámicos BALB C , Organismos Libres de Patógenos Específicos , Bazo/efectos de los fármacos
17.
Eur Spine J ; 30(9): 2577-2585, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-33740145

RESUMEN

PURPOSE: Although signal intensity on T2W axial images is sensitive in detection of fatty infiltration to assess paraspinal muscle degeneration, it is affected by inhomogeneities of magnetic fields and individual variabilities. The purpose of this study was to propose reference adjusted signal measures on T2W axial images and determine their capacities in reflecting age-related lumbar paraspinal muscle degeneration. METHODS: Lumbar MR images of 421 population-based subjects (177 men and 244 women, mean age 53.1 years, range 19.8-87.9 years) were studied. A custom software Spine Explore (Tulong 2.0) was used to automatically obtain paraspinal measurements of multifidus, erector spinae and psoas major. FCSA/TCSA was defined as functional cross-sectional area relative to total cross-sectional area of paraspinal muscle. Two new signal measures were canal-adjusted and cerebrospinal fluid (CSF)-adjusted signal, defined as the ratio between mean signal measurements and the mean signal of the canal and CSF. RESULTS: The raw signal measurements of the paraspinal muscles were weakly correlated to age (r = 0.28-0.39, P < 0.001). When the signal of canal (r = 0.43-0.59, P < 0.001) or CSF (r = 0.45-0.61, P < 0.001) was used as reference, the correlations substantially increased. Signal measurements of three paraspinal muscles, adjusted or not, were strongly associated with Goutallier score (ρ = 0.60-0.65, P < 0.001) and FCSA/TCSA (r = -0.64 to -0.82, P < 0.001). Greater Goutallier score was associated with greater age (r = 0.38-0.60, P < 0.001), while Lumbar indentation value (LIV) not. CONCLUSION: On routine T2W axial MR images the adjusted signal measurements using an internal reference of CSF or canal can better reflect age-related degenerative changes in the paraspinal muscles.


Asunto(s)
Imagen por Resonancia Magnética , Músculos Paraespinales , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Vértebras Lumbares/diagnóstico por imagen , Vértebras Lumbares/patología , Región Lumbosacra/diagnóstico por imagen , Masculino , Persona de Mediana Edad , Atrofia Muscular/patología , Músculos Paraespinales/diagnóstico por imagen , Músculos Paraespinales/patología , Adulto Joven
18.
Plant Dis ; 2021 Apr 29.
Artículo en Inglés | MEDLINE | ID: mdl-33926200

RESUMEN

Chilli pepper is an important economic crop and virus diseases are constraints on its production. In 2018, disease surveys were conducted at a 15-ha chilli pepper plantation in Dehong, southwest of Yunnan Province, China. Throughout the chilli pepper growing season from March to September, pepper plants developed three different virus-like symptoms on leaves, including mosaic, yellow mottle and shrinkage (Fig. S1). Based on observation of virus-like symptomatic phenotypes, the field surveys indicated that the disease incidence ranged from 30% in March to a peak 100% in July, resulting in a significant loss of pepper fruit from 30 to 100% depending on plot of the field. Potyvirus-like filamentous particles, around 11*760 nm, were observed under electron microscopy in the sap of symptomatic leaves (Fig. S1). To further determine the viral species in these samples, total RNA was extracted from three symptomatic samples using a Trans ZolUp Plus RNA Kit (Trans Gene, Beijing, China). Complementary DNA (cDNA) was synthesized using oligo (dT) and M-MLV reverse transcriptase (Promega, Madison, Wisconsin, USA) according to the manufacturer's instructions, and the polymerase chain reaction (PCR) was performed using degenerate primers specific to genus Potyvirus targeting HC-Pro region (HPFor: 5-TGYGAYAAYCARYTIGAYIIIAAYG-3; HPRev: 5-GAICCRWAIGARTCIAIIACRTG-3) (Ha et al. 2008) under the following conditions: an initial denaturation at 94°C for 4min, 30 cycles of denaturation at 94°C for 30 s, annealing at 56°C for 30 s, extension at 72°C for 30s, and a 10min final extension at 72°C. An expected 683-bp DNA fragment was amplified and cloned into the pMD 18-T Vector (Takara, Japan) for sequencing. Sequence analysis using BLAST revealed that the amplicons of phenotype I (Fig. S1a) shared highest nucleotide identity (85.6%) with wild tomato mosaic virus (WTMV) isolate from Vietnam (GenBank no. DQ851495) while the amplicons of phenotype III (Fig. S1c) showed the highest nucleotide identity (93%) with chilli veinal mottle virus (ChiVMV) isolate from Sichuan, China. (GenBank no. MK405594). Amplicons of phenotype II included both sequence of above WTMV and ChiVMV, indicating co-infection of phenotype II (Fig. S1b). Phenotype I sample was used for mechanical inoculation on chilli pepper as described previously (Yang et al.2013). After ten days, virus-like symptoms similar to phenotype I were observed on leaves, and WTMV infection, but not ChiVMV infection, was confirmed by RT-PCR tests on inoculated pepper plants (Fig. S1 e, f). To further ascertain the incidence of these two viruses in the field, primers WT-F: 5'-GTTGTTGAATGTGGTTTAGTT-3' and WT-R: 5'-AGATGTGCTTTGGAAGCGACC-3' were designed based on the WTMV sequence (GenBank no. DQ851495) to amplify a 476 bp product, and primers Ch-F/Ch-R (Ch-F: 5'-AAAGAAGAACAAGCGACAGAA-3', Ch-R: 5'-CATCACGCAAATATTCAAAGC-3') were designed based on ChiVMV sequence (GenBank no. MK405594.1) to amplify a 332 bp product. RT-PCR was conducted on 31 field-collected samples, and amplicons of expected sizes, 476bp and 332bp, corresponding to WTMV and ChiVMV, respectively, were obtained and sequenced to verify their identity. The results (Fig. S2) showed that 71% (22/31) of the samples tested positive for WTMV, 90% (28/31) tested positive for ChiVMV, and 65% (20/31) were co-infected with the two viruses. The WTMV was first reported infecting wild tomatoes in Vietnam in 2008 (Ha et al. 2008), and later reported in China in Nicotiana tabacum (Sun et al. 2015), Solanum nigrum (Zhang et al. 2019), and wild eggplant (Zhang et al. 2014). To our knowledge, this is the first report of WTMV infection on chilli pepper under natural conditions. Our study revealed that the chilli pepper disease in Dehong was caused by single or co-infection of WTMV and ChiVMV. It is necessary to find effective methods to control these two viruses.

19.
J Biol Chem ; 294(28): 10877-10885, 2019 07 12.
Artículo en Inglés | MEDLINE | ID: mdl-31138654

RESUMEN

Work in yeast models has benefitted tremendously from the insertion of epitope or fluorescence tags at the native gene locus to study protein function and behavior under physiological conditions. In contrast, work in mammalian cells largely relies on overexpression of tagged proteins because high-quality antibodies are only available for a fraction of the mammalian proteome. CRISPR/Cas9-mediated genome editing has recently emerged as a powerful genome-modifying tool that can also be exploited to insert various tags and fluorophores at gene loci to study the physiological behavior of proteins in most organisms, including mammals. Here we describe a versatile toolset for rapid tagging of endogenous proteins. The strategy utilizes CRISPR/Cas9 and microhomology-mediated end joining repair for efficient tagging. We provide tools to insert 3×HA, His6FLAG, His6-Biotin-TEV-RGSHis6, mCherry, GFP, and the auxin-inducible degron tag for compound-induced protein depletion. This approach and the developed tools should greatly facilitate functional analysis of proteins in their native environment.


Asunto(s)
Técnica del Anticuerpo Fluorescente/métodos , Ingeniería de Proteínas/métodos , Animales , Sistemas CRISPR-Cas/genética , Sistemas CRISPR-Cas/fisiología , Repeticiones Palindrómicas Cortas Agrupadas y Regularmente Espaciadas/genética , Reparación del ADN por Unión de Extremidades/genética , Reparación del ADN por Unión de Extremidades/fisiología , Colorantes Fluorescentes/química , Edición Génica/métodos , Células HEK293 , Humanos
20.
J Am Chem Soc ; 142(25): 10921-10925, 2020 Jun 24.
Artículo en Inglés | MEDLINE | ID: mdl-32484345

RESUMEN

Light-driven synthesis of plasmonic metal nanostructures has garnered broad scientific interests. Although it has been widely accepted that surface plasmon resonance (SPR)-generated energetic electrons play an essential role in this photochemical process, the exact function of plasmon-generated hot holes in regulating the morphology of nanostructures has not been fully explored. Herein, we discover that those hot holes work with surface adsorbates collectively to control the anisotropic growth of gold (Au) nanostructures. Specifically, it is found that hot holes stabilized by surface adsorbed iodide enable the site-selective oxidative etching of Au0, which leads to nonuniform growths along different lateral directions to form six-pointed Au nanostars. Our studies establish a molecular-level understanding of the mechanism behind the plasmon-driven synthesis of Au nanostars and illustrate the importance of cooperation between charge carriers and surface adsorbates in regulating the morphology evolution of plasmonic nanostructures.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA