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1.
Nature ; 627(8003): 321-327, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38480963

RESUMO

Overnight fires are emerging in North America with previously unknown drivers and implications. This notable phenomenon challenges the traditional understanding of the 'active day, quiet night' model of the diurnal fire cycle1-3 and current fire management practices4,5. Here we demonstrate that drought conditions promote overnight burning, which is a key mechanism fostering large active fires. We examined the hourly diurnal cycle of 23,557 fires and identified 1,095 overnight burning events (OBEs, each defined as a night when a fire burned through the night) in North America during 2017-2020 using geostationary satellite data and terrestrial fire records. A total of 99% of OBEs were associated with large fires (>1,000 ha) and at least one OBE was identified in 20% of these large fires. OBEs were early onset after ignition and OBE frequency was positively correlated with fire size. Although warming is weakening the climatological barrier to night-time fires6, we found that the main driver of recent OBEs in large fires was the accumulated fuel dryness and availability (that is, drought conditions), which tended to lead to consecutive OBEs in a single wildfire for several days and even weeks. Critically, we show that daytime drought indicators can predict whether an OBE will occur the following night, which could facilitate early detection and management of night-time fires. We also observed increases in fire weather conditions conducive to OBEs over recent decades, suggesting an accelerated disruption of the diurnal fire cycle.


Assuntos
Escuridão , Secas , Incêndios Florestais , Secas/estatística & dados numéricos , Ecossistema , América do Norte , Incêndios Florestais/estatística & dados numéricos
2.
J Cell Physiol ; 239(4): e31187, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38219047

RESUMO

Neural stem cells (NSCs) are pluripotent stem cells with the potential to differentiate into a variety of nerve cells. NSCs are susceptible to both intracellular and extracellular insults, thus causing DNA damage. Extracellular insults include ultraviolet, ionizing radiation, base analogs, modifiers, alkyl agents and others, while intracellular factors include Reactive oxygen species (ROS) radicals produced by mitochondria, mismatches that occur during DNA replication, deamination of bases, loss of bases, and more. When encountered with DNA damage, cells typically employ three coping strategies: DNA repair, damage tolerance, and apoptosis. NSCs, like many other stem cells, have the ability to divide, differentiate, and repair DNA damage to prevent mutations from being passed down to the next generation. However, when DNA damage accumulates over time, it will lead to a series of alterations in the metabolism of cells, which will cause cellular ageing. The ageing and exhaustion of neural stem cell will have serious effects on the body, such as neurodegenerative diseases. The purpose of this review is to examine the processes by which DNA damage leads to NSCs ageing and the mechanisms of DNA repair in NSCs.


Assuntos
Senescência Celular , Dano ao DNA , Células-Tronco Neurais , Reparo do DNA , Células-Tronco Neurais/fisiologia , Neurônios/fisiologia , Senescência Celular/genética , Humanos
3.
J Cell Physiol ; 239(5): e31216, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38327128

RESUMO

c-Fos, a member of the immediate early gene, serves as a widely used marker of neuronal activation induced by various types of brain damage. In addition, c-Fos is believed to play a regulatory role in DNA damage repair. This paper reviews the literature on c-Fos' involvement in the regulation of DNA damage repair and indicates that genes of the Fos family can be induced by various forms of DNA damage. In addition, cells lacking c-Fos have difficulties in DNA repair. c-Fos is involved in tumorigenesis and progression as a proto-oncogene that maintains cancer cell survival, which may also be related to DNA repair. c-Fos may impact the repair of DNA damage by regulating the expression of downstream proteins, including ATR, ERCC1, XPF, and others. Nonetheless, the underlying mechanisms necessitate further exploration.


Assuntos
Dano ao DNA , Reparo do DNA , Proto-Oncogene Mas , Proteínas Proto-Oncogênicas c-fos , Humanos , Reparo do DNA/genética , Dano ao DNA/genética , Proteínas Proto-Oncogênicas c-fos/metabolismo , Proteínas Proto-Oncogênicas c-fos/genética , Animais , Neoplasias/genética , Neoplasias/patologia , Neoplasias/metabolismo
4.
Biochem Soc Trans ; 52(3): 1363-1372, 2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38747731

RESUMO

The zinc finger protein of the cerebellum (ZIC) family comprises five members (ZIC1-5), homologous with the odd-paired (OPA) gene in Drosophila melanogila. These transcription factors contain five Cys2His zinc finger domains, constituting one of the most abundant transcription factor families in human cells. ZIC proteins significantly contribute to transcriptional regulation and chromatin remodeling. As a member of the ZIC family, ZIC5 is essential for animal growth and development. Numerous studies have investigated the connection between ZIC proteins and cancer as well as tumor metastases in recent years. Many studies have found that within tumor tissues, the transcription and translation processes increase the expression of ZIC5 which is linked to tumor aggressiveness. This review aims to provide an objective summary of the impact of ZIC5 on tumor metastasis and consider the potential application of ZIC5 targets in both tumor therapy and the early detection of cancer.


Assuntos
Metástase Neoplásica , Neoplasias , Fatores de Transcrição , Humanos , Fatores de Transcrição/metabolismo , Animais , Neoplasias/metabolismo , Neoplasias/patologia , Neoplasias/genética , Proteínas de Ligação a DNA/metabolismo , Proteínas de Ligação a DNA/genética , Regulação Neoplásica da Expressão Gênica
5.
Glob Chang Biol ; 30(3): e17221, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38450880

RESUMO

Communities interspersed throughout the Canadian wildland are threatened by fires that have become bigger and more frequent in some parts of the country in recent decades. Identifying the fireshed (source area) and pathways from which wildland fire may ignite and spread from the landscape to a community is crucial for risk-reduction strategy and planning. We used outputs from a fire simulation model, including fire polygons and rate of spread, to map firesheds, fire pathways and corridors and spread distances for 1980 communities in the forested areas of Canada. We found fireshed sizes are larger in the north, where the mean distances between ecumene and fireshed perimeters were greater than 10 km. The Rayleigh Z test indicated that simulated fires around a large proportion of communities show significant directional trends, and these trends are stronger in the Boreal Plains and Shields than in the Rocky Mountain area. The average distance from which fire, when spreading at the maximum simulated rate, could reach the community perimeter was approximately 5, 12 and 18 km in 1, 2 and 3 days, respectively. The average daily spread distances increased latitudinally, from south to north. Spread distances were the shortest in the Pacific Maritime, Atlantic Maritime and Boreal Plains Ecozones, implying lower rates of spread compared to the rest of the country. The fire corridors generated from random ignitions and from ignitions predicted from local fire history differ, indicating that factors other than fuel (e.g. fire weather, ignition pattern) play a significant role in determining the direction that fires burn into a community.


Assuntos
Desastres , Incêndios Florestais , Canadá , Simulação por Computador , Florestas
6.
Mol Biol Rep ; 51(1): 512, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38622483

RESUMO

Bacterial enteritis has a substantial role in contributing to a large portion of the global disease burden and serves as a major cause of newborn mortality. Despite advancements gained from current animal and cell models in improving our understanding of pathogens, their widespread application is hindered by apparent drawbacks. Therefore, more precise models are imperatively required to develop more accurate studies on host-pathogen interactions and drug discovery. Since the emergence of intestinal organoids, massive studies utilizing organoids have been conducted to study the pathogenesis of bacterial enteritis, revealing new mechanisms and validating established ones. In this review, we focus on the advancements of several bacterial pathogenesis mechanisms observed in intestinal organoid/enteroid models, exploring the host response and bacterial effectors during the infection process. Finally, we address the features that warrant additional investigation or could be enhanced in existing organoid models in order to guide future research endeavors.


Assuntos
Infecções Bacterianas , Enterite , Animais , Intestinos/microbiologia , Bactérias , Organoides
7.
Small ; 19(42): e2301638, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37345962

RESUMO

Developing composite materials with optimized mechanics, degradation, and bioactivity for bone regeneration has long been a crucial mission. Herein, a multifunctional Mg/Poly-l-lactic acid (Mg/PLLA) composite membrane based on the "materials plain" concept through the accumulative rolling (AR) method is proposed. Results show that at a rolling ratio of 75%, the comprehensive mechanical properties of the membrane in the rolling direction are self-reinforced significantly (elongation at break ≈53.2%, tensile strength ≈104.0 MPa, Young's modulus ≈2.13 GPa). This enhancement is attributed to the directional arrangement and increased crystallization of PLLA molecular chains, as demonstrated by SAXS and DSC results. Furthermore, the AR composite membrane presents a lamellar heterostructure, which not only avoids the accumulation of Mg microparticles (MgMPs) but also regulates the degradation rate. Through the contribution of bioactive MgMPs and their photothermal effect synergistically, the membrane effectively eliminates bacterial infection and accelerates vascularized bone regeneration both in vitro and in vivo. Notably, the membrane exhibits outstanding rat skull bone regeneration performance in only 4 weeks, surpassing most literature reports. In short, this work develops a composite membrane with a "one stone, four birds" effect, opening an efficient avenue toward high-performance orthopedic materials.


Assuntos
Regeneração Óssea , Poliésteres , Ratos , Animais , Espalhamento a Baixo Ângulo , Difração de Raios X , Poliésteres/química , Bactérias
8.
Stem Cells ; 40(5): 493-507, 2022 05 27.
Artigo em Inglês | MEDLINE | ID: mdl-35349711

RESUMO

DNA damage is assumed to accumulate in stem cells over time and their ability to withstand this damage and maintain tissue homeostasis is the key determinant of aging. Nonetheless, relatively few studies have investigated whether DNA damage does indeed accumulate in stem cells and whether this contributes to stem cell aging and functional decline. Here, we found that, compared with young mice, DNA double-strand breaks (DSBs) are reduced in the subventricular zone (SVZ)-derived neural stem cells (NSCs) of aged mice, which was achieved partly through the adaptive upregulation of Sirt1 expression and non-homologous end joining (NHEJ)-mediated DNA repair. Sirt1 deficiency abolished this effect, leading to stem cell exhaustion, olfactory memory decline, and accelerated aging. The reduced DSBs and the upregulation of Sirt1 expression in SVZ-derived NSCs with age may represent a compensatory mechanism that evolved to protect stem cells from excessive DNA damage, as well as mitigate memory loss and other stresses during aging.


Assuntos
Ventrículos Laterais , Células-Tronco Neurais , Sirtuína 1 , Envelhecimento/genética , Animais , DNA/metabolismo , Quebras de DNA de Cadeia Dupla , Reparo do DNA por Junção de Extremidades , Reparo do DNA , Ventrículos Laterais/metabolismo , Camundongos , Células-Tronco Neurais/metabolismo , Sirtuína 1/genética , Sirtuína 1/metabolismo
9.
Analyst ; 148(19): 4710-4720, 2023 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-37622207

RESUMO

Raman hyperspectral imaging is an effective method for label-free imaging with chemical specificity, yet the weak signals and correspondingly long integration times have hindered its wide adoption as a routine analytical method. Recently, low resolution Raman imaging has been proposed to improve the spectral signal-to-noise ratio, which significantly improves the speed of Raman imaging. In this paper, low resolution Raman spectroscopy is combined with "context-aware" matrix completion, where regions of the sample that are not of interest are skipped, and the regions that are measured are under-sampled, then reconstructed with a low-rank constraint. Both simulations and experiment show that low-resolution Raman boosts the speed and image quality of the computationally-reconstructed Raman images, allowing deeper sub-sampling, reduced exposure time, and an overall >10-fold improvement in imaging speed, without sacrificing chemical specificity or spatial image quality. As the method utilizes traditional point-scan imaging, it retains full confocality and is "backwards-compatible" with pre-existing traditional Raman instruments, broadening the potential scope of Raman imaging applications.

10.
Analyst ; 148(12): 2809-2817, 2023 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-37219873

RESUMO

The weak signal strength of Raman imaging leads to long imaging times. To increase the speed of Raman imaging, line scanning and compressed Raman imaging methods have been proposed. Here we combine both line scanning and compressed sensing to further increase the speed. However, the direct combination leads to poor reconstruction results due to the missed coverage of the sample. To avoid this issue, "full-coverage" Compressed Line-scan Raman Imaging (FC-CLRI) is proposed, where line positions are random but constrained to measure each line position of the sample at least once. In proof-of-concept studies of polymer beads and yeast cells, FC-CLRI achieved reasonable image quality while making only 20-40% of the measurements of a fully-sampled line-scan image, achieving 640 µm2 FOV imaging in <2 min with 1.5 mW µm-2 laser power. Furthermore, we critically evaluate the CLRI method through comparison with simple downsampling, and have found that FC-CLRI preserves spatial resolution better while naïve downsampling provides an overall higher image quality for complex samples.

11.
Anal Chem ; 94(41): 14232-14241, 2022 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-36202399

RESUMO

Laser tweezers Raman spectroscopy enables multiplexed, quantitative chemical and morphological analysis of individual bionanoparticles such as drug-loaded nanoliposomes, yet it requires minutes-scale acquisition times per particle, leading to a lack of statistical power in typical small-sized data sets. The long acquisition times present a bottleneck not only in measurement time but also in the analytical throughput, as particle concentration (and thus throughput) must be kept low enough to avoid swarm measurement. The only effective way to improve this situation is to reduce the exposure time, which comes at the expense of increased noise. Here, we present a hybrid principal component analysis (PCA) denoising method, where a small number (∼30 spectra) of high signal-to-noise ratio (SNR) training data construct an effective principal component subspace into which low SNR test data are projected. Simulations and experiments prove the method outperforms traditional denoising methods such as the wavelet transform or traditional PCA. On experimental liposome samples, denoising accelerated data acquisition from 90 to 3 s, with an overall 4.5-fold improvement in particle throughput. The denoised data retained the ability to accurately determine complex morphochemical parameters such as lamellarity of individual nanoliposomes, as confirmed by comparison with cryo-EM imaging. We therefore show that hybrid PCA denoising is an efficient and effective tool for denoising spectral data sets with limited chemical variability and that the RR-NTA technique offers an ideal path for studying the multidimensional heterogeneity of nanoliposomes and other micro/nanoscale bioparticles.


Assuntos
Algoritmos , Lipossomos , Análise de Componente Principal , Razão Sinal-Ruído , Análise Espectral Raman
12.
Saudi Pharm J ; 30(10): 1418-1425, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36387336

RESUMO

Objective: To determine the use and tendency of drugs for postpartum depression (PPD) in nine cities across China in 2016-2020 in order to provide a reference for drug use in the clinic. Methods: The prescription data of drugs for PPD outpatients in nine cities (Beijing, Chengdu, Guangzhou, Harbin, Hangzhou, Shanghai, Shenyang, Tianjin and Zhengzhou) across China in 2016-2020 were extracted from the Hospital Prescription Analysis Cooperation Project database of the Hospital Pharmacy Professional Committee of Chinese Pharmaceutical Association. A cross-sectional analysis was then conducted of patient age, total prescription quantity, average prescription amount, defined daily doses (DDDs) of drugs, defined daily cost (DDC) of drugs and so on. Results: In 2016-2020, more than half of PPD patients in these nine cities were distributed in first-tier cities (Beijing, Shanghai and Guangzhou), and were mainly aged 30-39 years. During the five-year period, the prescription quantity, total prescription amount and average prescription amount increased by 20.95%, 35.41% and 11.02%, respectively. In terms of prescription frequency and prescription amount, selective serotonin reuptake inhibitors (SSRIs) ranked first, followed by serotonin-norepinephrine reuptake inhibitors (SNRIs). With regard to DDDs, escitalopram, sertraline, paroxetine and venlafaxine ranked high, and sertraline was top year by year. The DDC of vortioxetine and milnacipran was greatest, while that of escitalopram, olanzapine and quetiapine declined sharply after being included in the China centralized drug-procurement program. Conclusion: The number of PPD patients and the total prescription amount in the nine cities across China increased in 2016-2020. SSRIs and SNRIs were the main drugs for PPD treatment. Due to the national centralized drug-procurement policy, there has been a great reduction in the DDC, lightening the economic burden on patients.

13.
Analyst ; 146(7): 2348-2357, 2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33624650

RESUMO

Raman hyperspectral imaging is a powerful method to obtain detailed chemical information about a wide variety of organic and inorganic samples noninvasively and without labels. However, due to the weak, nonresonant nature of spontaneous Raman scattering, acquiring a Raman imaging dataset is time-consuming and inefficient. In this paper we utilize a compressive imaging strategy coupled with a context-aware image prior to improve Raman imaging speed by 5- to 10-fold compared to classic point-scanning Raman imaging, while maintaining the traditional benefits of point scanning imaging, such as isotropic resolution and confocality. With faster data acquisition, large datasets can be acquired in reasonable timescales, leading to more reliable downstream analysis. On standard samples, context-aware Raman compressive imaging (CARCI) was able to reduce the number of measurements by ∼85% while maintaining high image quality (SSIM >0.85). Using CARCI, we obtained a large dataset of chemical images of fission yeast cells, showing that by collecting 5-fold more cells in a given experiment time, we were able to get more accurate chemical images, identification of rare cells, and improved biochemical modeling. For example, applying VCA to nearly 100 cells' data together, cellular organelles were resolved that were not faithfully reconstructed by a single cell's dataset.

14.
J Clin Pharm Ther ; 46(1): 78-85, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32875586

RESUMO

WHAT IS KNOWN AND OBJECTIVE: Drug consultation is an important part of pharmaceutical care offered by clinical pharmacists. We explored the characteristics of telephone drug consultations in an obstetrics and gynaecology speciality hospital to provide a reference as to how to improve drug consultation and pharmaceutical care. METHODS: We retrospectively analysed records of telephone consultations regarding medication use between 2014 and 2019 in our hospital. Any consultation cases with incomplete records were excluded from our analysis. Of the 1353 consultation cases included in our study, we further classified them into different categories based on the content of the consultations, the type of medications being inquired about, and the groups of people who sought medication guidance. Pareto analysis was performed to separate the main issues the callers were concerned about from the more minor concerns. RESULTS AND DISCUSSION: The medication issues that prompted the caller to consult with our clinical pharmacists could be divided into 12 categories, among which the main issues concerned usage and dosage, choice of drug variety, drug incompatibility (drug mixture in infusion bag or tube), adjustment of the treatment plan, and skin tests (cumulative percentage 76.3%). The minor issues involved medication use during pregnancy and lactation and adverse reactions. The top three types of drugs that callers asked about were antimicrobials (600 cases, 44.4%), anti-tumour drugs (151 cases, 11.2%) and reproductive system drugs (111 cases, 8.2%). The callers could be divided into four groups as follows: doctors (865 cases, 63.9%), nurses (280 cases, 20.7%), patients (116 cases, 8.6%) and other medical professionals (92 cases, 6.8%). WHAT IS NEW AND CONCLUSION: Usage and dosage, choice of drug variety, drug incompatibility, adjustment of treatment plan and skin tests represented the main issues for telephone drug consultations in our hospital. Doctors and nurses were most likely to consult clinical pharmacists regarding these issues. Improved drug consultation services are needed to allow more patients to have access to advice from pharmacists. Such access would better enable pharmacists to fulfil their roles in advising the appropriate use of drugs to ensure better patient care and medication compliance.


Assuntos
Preparações Farmacêuticas/administração & dosagem , Encaminhamento e Consulta/normas , Telemedicina/normas , Adolescente , Adulto , Feminino , Ginecologia , Hospitais , Humanos , Prontuários Médicos , Obstetrícia , Gravidez , Melhoria de Qualidade , Estudos Retrospectivos , Adulto Jovem
15.
Molecules ; 26(5)2021 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-33806482

RESUMO

An effective and sensitive method is necessary for the determination of polybrominated diphenyl ethers (PBDEs) pollutants in water. In this study, effervescent-assisted dispersive liquid-liquid microextraction with solidification of the aqueous phase (EA-DLLME-SAP), followed by Gas Chromatography-Tandem Mass Spectrometry (GC-MS-MS) quantitative analysis, was established for the preconcentration and determination of PBDEs in real environmental water samples. 1,1,2,2-Tetrachloroethane was used as the extractant and directly dispersed into the water phase of the aqueous samples with the aid of a large number of carbon dioxide bubbles generated via the acid-base reaction of acetic acid and sodium bicarbonate, which did not require the use of a dispersant during the extraction process. The key factors affecting the extraction recovery were optimized, and an internal standard was used for quantitative analysis, which gave good linearity ranges of 1-100 ng·L-1 (BDEs 28, 47, 99, and 100), 2-200 ng·L-1 (BDEs 153, 154, and 183) and 5-500 ng·L-1 (BDE 209) with limits of quantification in the range of 1.0-5.0 ng·L-1. The accuracy was verified with relative standard deviations < 8.5% observed in tap, lake, river and reservoir water samples with relative recoveries ranging from 67.2 to 102.6%. The presented method contributes to the determination of PBDEs in environmental water samples.


Assuntos
Éteres Difenil Halogenados/análise , Hidrocarbonetos Bromados/análise , Microextração em Fase Líquida/instrumentação , Microextração em Fase Líquida/métodos , Poluentes Químicos da Água/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos
16.
Analyst ; 145(20): 6607-6616, 2020 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-32789319

RESUMO

The majority of problems in analytical Raman spectroscopy are mathematically over-determined, where many more spectral variables are measured than analytic outputs (such as chemical concentrations) are calculated. Thus, to improve spectral throughput and simplify system design, some researchers have explored the use of low resolution Raman systems for cell or tissue classification, achieving accuracy independent of spectral resolution. However, the tradeoffs inherent in this approach have not been systematically studied. Here, we theoretically and experimentally explore the relationship between spectral resolution and analytical error. We show that decreased spectral resolution leads to spectral signal-to-noise ratio and therefore more reliable results and lower limits of detection for equivalent integration times in blind unmixing of hyperspectral images. Our theoretical analysis demonstrates that the primary benefit of low resolution Raman spectroscopy is in overcoming detector noise (such as thermal or electronic noise). Therefore, the benefits are most pronounced when utilizing lower-grade, uncooled detectors. Therefore, using a low-cost CMOS camera we experimentally demonstrate the ability of low resolution Raman spectroscopy to achieve substantially improved imaging performance compared to fully-resolved Raman spectral imaging, paving the way for cost-effective, pervasive Raman spectroscopy.


Assuntos
Imageamento Hiperespectral , Análise Espectral Raman , Diagnóstico por Imagem , Limite de Detecção
17.
J Sep Sci ; 43(8): 1499-1513, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32059263

RESUMO

The quantity of soil fumigants has increased globally that has focused attention on their environmental behavior. However, simultaneous analysis of traces of fumigant residues is often unreported because analysis methods are not readily available to measure them at low concentrations. In this study, typical solvent extraction methods were compared with headspace solid-phase microextraction methods. Both methods can be used for simultaneously measuring the concentrations of five commonly used soil fumigants in soil or water. The solvent extraction method showed acceptable recovery (76-103%) and intraday relative standard deviations (0.8-11%) for the five soil fumigants. The headspace solid-phase microextraction method also showed acceptable recovery (72-104%) and precision rates (1.3-17%) for the five soil fumigants. The solvent extraction method was more precise and more suitable for analyzing relatively high fumigant residue levels (0.05-5 µg/g) contained in multiple soil samples. The headspace solid-phase microextraction method, however, had a much lower limits of detection (0.09-2.52 µg/kg or µg/L) than the solvent extraction method (5.8-29.2 µg/kg), making headspace solid-phase microextraction most suitable for trace analysis of these fumigants. The results confirmed that the headspace solid-phase microextraction method was more convenient and sensitive for the determination of fumigants to real soil samples.

18.
Ecotoxicol Environ Saf ; 187: 109850, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31677569

RESUMO

Soil fumigation is currently the most effective method for controlling soil-borne pests and diseases in high-value crops. To better understand the effect of chloropicrin (CP), dazomet (DZ), dimethyl disulfide (DMDS), allyl isothiocyanate (AITC) and 1,3-dichloropropene (1,3-D) fumigants on soil microorganisms, this study monitored changes in the diversity and community composition of soil bacteria involved in denitrification using real-time PCR and high-throughput gene sequencing techniques. These five fumigants significantly decreased the bacterial population size in some phyla including Proteobacteria, Chloroflexi and Acidobacteria, and increased the bacterial population size in other phyla such as Firmicutes, Gemmatimonadetes, Actinobacteria, Verrucomicrobia, Saccharibacteria and Parcubacteria. Although bacterial diversity declined after CP fumigation, it was briefly stimulated by the other four fumigants. Meanwhile, all five fumigants temporarily decreased populations of denitrifying bacteria containing the napA, narG, nirS or nirK enzyme-encoding genes. Denitrifiers bearing the cnorB, qnorB or nosZ genes were relatively stable following DZ and DMDS fumigation. However, cnorB and nosZ decreased initially following CP, AITC and 1,3-D fumigation. Simultaneously, the abundance of qnorB significantly increased in AITC and 1,3-D fumigated soils. These results showed that soil fumigation significantly shifted the abundance and community structure of denitrifying bacteria. This study will help to predict the response of different phyla of denitrifying bacteria to soil fumigation.


Assuntos
Bactérias Anaeróbias/efeitos dos fármacos , Fumigação , Microbiota/efeitos dos fármacos , Resíduos de Praguicidas/toxicidade , Microbiologia do Solo , Poluentes do Solo/toxicidade , Bactérias Anaeróbias/genética , Bactérias Anaeróbias/crescimento & desenvolvimento , Biodiversidade , Desnitrificação , Microbiota/genética , Solo/química
19.
Sensors (Basel) ; 20(6)2020 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-32204389

RESUMO

During the operation of rotating machinery, the vibration signals measured by sensors are the aliasing signals of various vibration sources, and they contain strong noises. Conventional signal processing methods have difficulty separating the aliasing signals, which causes great difficulties in the condition monitoring and fault diagnosis of the equipment. The principle and method of blind source separation are introduced, and it is pointed out that the blind source separation algorithm is invalid in strong pulse noise environments. In these environments, the vibration signals are first de-noised with the median filter (MF) method and the de-noised signals are separated with an improved joint approximate diagonalization of eigenmatrices (JADE) algorithm. The simulation results found here verify the effectiveness of the proposed method. Finally, the vibration signal of the hybrid rotor is effectively separated by the proposed method. A new separation approach is thus provided for vibration signals in strong pulse noise environments.

20.
Water Sci Technol ; 81(4): 813-823, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32460284

RESUMO

A nitrogen-doped reduced graphene oxide/Fe3O4 composite (NGO-Fe3O4) was prepared through the simplified hydrothermal and deposition-precipitation method and characterized by X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy. The degradation efficiency of oxytetracycline (OTC) by NGO-Fe3O4 activated peroxodisulfate (PDS) under visible light irradiation was studied. The degradation efficiency reached 100% within 32.5 min (the initial OTC concentration 50 mg L-1 and PDS 1 mM; [NGO-Fe3O4]:[ PDS] = 4:1; pH = 3.0). No apparent decrease in degradation efficiency was observed after five cycles. SO4 -· and ·OH were the main active oxides for OTC degradation in this system. Moreover, four degradation pathways were proposed, namely hydroxylation, dehydration, decarbonylation and demethylation according to the analysis results of high-performance liquid chromatography mass spectrometry.


Assuntos
Oxitetraciclina , Luz , Microscopia Eletrônica de Varredura , Óxidos , Difração de Raios X
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