Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 70
Filtrar
Mais filtros

Bases de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Anal Chem ; 96(2): 710-720, 2024 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-38175632

RESUMO

Sterigmatocystin (ST) is a known toxin whose aptamer has rarely been reported because ST is a water-insoluble small-molecule target with few active sites, leading to difficulty in obtaining its aptamer using traditional target fixation screening methods. To obtain aptamer for ST, we incorporated FAM tag size separation into the capture-systematic evolution of ligands by exponential enrichment and combined it with molecular activation for aptamer screening. The screening process was monitored using a quantitative polymerase chain reaction fluorescence amplification curve and recovery of negative-, counter-, and positive-selected ssDNA. The affinity and specificity of the aptamer were verified by constructing an aptamer-affinity column, and the binding sites were predicted using molecular docking simulations. The results showed that the Kd value of the H Seq02 aptamer was 25.3 nM. The aptamer-affinity column based on 2.3 nmol of H Seq02 exhibited a capacity of about 80 ng, demonstrating better specificity than commercially available antibody affinity columns. Molecular simulation docking predicted the binding sites for H Seq02 and ST, further explaining the improved specificity. In addition, circular dichroism and isothermal titration calorimetry were used to verify the interaction between the aptamer and target ST. This study lays the foundation for the development of a new ST detection method.


Assuntos
Aptâmeros de Nucleotídeos , Aptâmeros de Nucleotídeos/química , Esterigmatocistina , Técnica de Seleção de Aptâmeros/métodos , Simulação de Acoplamento Molecular , Ligantes
2.
J Sci Food Agric ; 2024 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-38979962

RESUMO

BACKGROUND: Alicyclobacillus acidoterrestris is a common microorganism in fruit juice. It can produce off-odor metabolites and has been considered to be an important factor in juice contamination. Thus, the development of new strategy for the control of A. acidoterrestris has important practical significance. The primary objective of this work was to assess the antibacterial performance of ε-polylysine-functionalized magnetic composites (Fe3O4@MoS2@PAA-EPL) in apple juice and its effect on juice quality. Moreover, the molecular mechanism of Fe3O4@MoS2@PAA-EPL against A. acidoterrestris was explored by RNA sequencing (RNA-Seq). RESULTS: Experimental results indicated that the synthesized composites possessed the ability to inhibit the viability of A. acidoterrestris vegetative cells and spores. Besides, investigation on the quality of apple juice incubated with Fe3O4@MoS2@PAA-EPL implied that the fabricated composites displayed negligible adverse effects on juice quality. In addition, the results of RNA-Seq demonstrated that 833 differentially expressed genes (DEGs) were identified in Fe3O4@MoS2@PAA-EPL-treated A. acidoterrestris, which were associated with translation, energy metabolism, amino acid metabolism, membrane transport and cell integrity. CONCLUSION: These results suggested that the treatment of Fe3O4@MoS2@PAA-EPL disrupted energy metabolism, repressed cell wall synthesis and caused membrane transport disorder of bacterial cells. This work provides novel insights into the molecular antibacterial mechanism for ε-polylysine-functionalized magnetic composites against A. acidoterrestris. © 2024 Society of Chemical Industry.

3.
Altern Ther Health Med ; 29(2): 22-28, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36239566

RESUMO

Context: The totally implantable venous access port (TIVAP) is an intravenous-infusion device, with a lower complication rate than other such devices. If patients fail to maintain the catheter, however, complications can still occur. Patients' needs may vary by the period of the port's use. Objective: The study intended to explore the differences in the needs of breast-cancer (BC) patients with TIVAPs for health education and nursing care at different periods of the port's use and to determine the kinds of targeted health education that can improve patients' quality of life. Design: The research team designed a questionnaire that the participants completed. Setting: The study took place at the Breast Center at the Fourth Hospital of Hebei Medical University in Shijiazhuang, China. Participants: Participants were 442 BC patients at the hospital between March and June 2020, who had TIVAPs at different stages. Groups: The study included three groups: (1) the preoperative group-participants in the preoperative period prior to the TIVAP implantation after they had signed a consent; (2) the chemotherapy group-participants in the chemotherapy period during the TIVAP's use for chemotherapy-agent transfusion, and (3) the maintenance group-participants in the maintenance period during which the TIVAD was in place but wasn't being used. Outcome Measures: The research team analyzed the results from the questionnaires, categorizing them as: (1) methods of knowledge acquisition, (2) methods of distribution of knowledge, (3) needs of participants in the different groups, and (4) distribution of symptoms among the groups. Results: Compared to other methods, the nursing staff was the main source that participants used to access the TIVAP-related information at different periods: preoperative group (79.6%), chemotherapy group (90.7%), and maintenance group (90.2%).The differences between the periods were statistically significant (P = .00). A traditional mode of education-the medical staff's explanations-was the most common in all groups: preoperative group (79.6%), chemotherapy group (83.3%), and (3) maintenance group (80.7%). Patients wanted new modes of receiving information: talks, a poster, and a medical system. TIVAP patients paid different amounts of attention to educational contents at the different stages (χ2 = 29.816, P = .00). Conclusions: BC patients' needs for health education and nursing vary at different stages when using TIVAPs. Nurses are the main source of knowledge about TIVAP in different periods for BC patients, and the nurses should obtain multidisciplinary health knowledge to enhance the benefits of the education for patients. The current education for patient is traditional, and hospitals need to implement new modes of education such as medical systems and network platforms, lectures, and posters for health education.


Assuntos
Neoplasias da Mama , Cateterismo Venoso Central , Humanos , Feminino , Neoplasias da Mama/tratamento farmacológico , Cateterismo Venoso Central/métodos , Cateteres de Demora , Qualidade de Vida , Educação em Saúde
4.
Compr Rev Food Sci Food Saf ; 22(1): 355-379, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36382862

RESUMO

Protein and amino acid oxidation in food products produce many new compounds, of which the reactive and toxic compound dityrosine, derived from oxidized tyrosine, is the most widely studied. The high reactivity of dityrosine enables this compound to induce oxidative stress and disrupt thyroid hormone function, contributing to the pathological processes of several diseases, such as obesity, diabetes, cognitive dysfunction, aging, and age-related diseases. From the perspective of food safety and human health, protein-oxidation products in food are the main concern of consumers, health management departments, and the food industry. This review highlights the latest research on the formation pathways, toxicity, detection methods, occurrence in food, and mitigation strategies for dityrosine. Furthermore, the control of dityrosine in family cooking and food-processing industry has been discussed. Food-derived dityrosine primarily originates from high-protein foods, such as meat and dairy products. Considering its toxicity, combining rapid high sensitivity dityrosine detection techniques with feasible control methods could be an effective strategy to ensure food safety and maintain human health. However, the current dityrosine detection and mitigation strategies exhibit some inherent characteristics and limitations. Therefore, developing technologies for rapid and effective dityrosine detection and control at the industrial level is necessary.


Assuntos
Proteínas , Tirosina , Humanos , Tirosina/química , Tirosina/metabolismo , Estresse Oxidativo , Alimentos
5.
Zhong Nan Da Xue Xue Bao Yi Xue Ban ; 48(6): 829-836, 2023 Jun 28.
Artigo em Inglês, Zh | MEDLINE | ID: mdl-37587067

RESUMO

OBJECTIVES: This study aims to investigate the genome-wide DNA methylation and transcriptome expression profiles of peripheral blood mononuclear cells (PBMCs) in patients with systemic sclerosis (SSc) with interstitial lung disease (ILD), and to analyze the effects of DNA methylation on Wnt/ß-catenin and chemokine signaling pathways. METHODS: PBMCs were collected from 19 patients with SSc (SSc group) and 18 healthy persons (control group). Among SSc patients, there were 10 patients with ILD (SSc with ILD subgroup) and 9 patients without ILD (SSc without ILD subgroup). The genome-wide DNA methylation and gene expression level were analyzed by using Illumina 450K methylation chip and Illumina HT-12 v4.0 gene expression profiling chip. The effect of DNA methylation on Wnt/ß-catenin and chemokine signal pathways was investigated. RESULTS: Genome-wide DNA methylation analysis identified 71 hypermethylated CpG sites and 98 hypomethylated CpG sites in the SSc with ILD subgroup compared with the SSc without ILD subgroup. Transcriptome analysis distinguished 164 upregulated genes and 191 downregulated genes in the SSc with ILD subgroup as compared with the SSc without ILD subgroup. In PBMCs of the SSc group, 35 genes in Wnt/ß-catenin signaling pathway were hypomethylated, while frizzled-1 (FZD1), mitogen-activated protein kinase 9 (MAPK9), mothers against DPP homolog 2 (SMAD2), transcription factor 7-like 2 (TCF7L2), and wingless-type MMTV integration site family, member 5B (WNT5B) mRNA expressions were upregulated as compared with the control group (all P<0.05). Compared with the SSc without ILD subgroup, the mRNA expressions of dickkopf homolog 2 (DKK2), FZD1, MAPK9 were upregulated in the SSc with ILD subgroup, but the differences were not statistically significant (all P>0.05). In PBMCs of the SSc group, 38 genes in chemokine signaling pathway were hypomethylated, while ß-arrestin 1 (ARRB1), C-X-C motif chemokine ligand 10 (CXCL10), C-X-C motif chemokine ligand 16 (CXCL16), FGR, and neutrophil cytosolic factor 1C (NCF1C) mRNA expressions were upregulated as compared with the control group (all P<0.05). Compared with the SSc without ILD subgroup, the mRNA expressions of ARRB1, CXCL10, CXCL16 were upregulated in the SSc with ILD subgroup, but the differences were not statistically significant (all P>0.05). CONCLUSIONS: There are differences in DNA methylation and transcriptome profiles between SSc with ILD and SSc without ILD. The expression levels of multiple genes in Wnt/ß- catenin and chemokine signaling pathways are upregulated, which might be associatea with the pathogenesis of SSc.


Assuntos
Metilação de DNA , Transcriptoma , Humanos , beta Catenina , Leucócitos Mononucleares , Ligantes , DNA , RNA Mensageiro/genética
6.
J Sci Food Agric ; 102(5): 1842-1850, 2022 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-34460956

RESUMO

BACKGROUND: Since anthocyanin has good coloration and antioxidant properties, many studies have focused on exploring the stability and antioxidant activity of anthocyanin. The objective of this work was to study effects of pH and temperature on the bioactivity of cyanidin-3-O-glucoside (C3G) and ultra-performance liquid chromatography-photodiode array-electrospray ionization-quadrupole-time-of-flight mass spectrometry (UPLC-PDA-ESI-Q-TOF-MS) and density functional theory (DFT) were used to explain the mechanism of structural transformation of C3G affecting their bioactivity at the molecular level. RESULTS: During the heating process at pH 2.2 to 7.0,the flavylium cation content of C3G decreased from 92.71% to 51.64% and the chalcone content increased from 7.29% to 30.61%. The quinoidal base and first discovery of the degradation product of the C3G, 1-(3,4-dihydroxy-phenyl)-2-(3, 4,5-trihydroxy-6-hydroxymethyl-tetrahydro-pyran-2-yloxy)-ethanone, were only detected in heated samples at pH 7.0. DFT revealed the antioxidant mechanism was mediated by sequential proton loss electron transfer and the antioxidant activity of C3G in pH 5.0 and 7.0 environments was higher than that in the pH 2.2 environment. CONCLUSIONS: The results revealed the thermal degradation products of C3G included catechin, 3,4-dihydroxybenzoic acid, 2,4,6-trihydroxy-benzaldehyde and 1-(3,4-Dihydroxy-phenyl)-2-(3,4,5-trihydroxy-6-hydroxymethyl-tetrahydro-pyran-2-yloxy)-ethanone. C3G had higher antioxidant activity in weakly acidic to near-neutral environments and the reactive sites were most likely at the 4'-OH and 5-OH sites. © 2021 Society of Chemical Industry.


Assuntos
Antocianinas , Glycine max , Antocianinas/química , Antioxidantes/química , Glucosídeos/metabolismo , Temperatura Alta , Concentração de Íons de Hidrogênio , Glycine max/química
7.
Appl Microbiol Biotechnol ; 105(12): 5147-5158, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34086115

RESUMO

o-Vanillin is a natural product that has been widely applied in the food and pharmaceutical industries. In this study, we determined that o-vanillin can strongly inhibit the growth of Aspergillus flavus mycelia. However, the inhibition mechanism of o-vanillin is still elusive. The ultrastructural morphology of mycelia was injured, and the cell walls were destroyed. The OH functional groups on cell walls were altered, and the content of protein in mycelial cell walls was reduced by o-vanillin. The content of ß-1,3-glucan in cell walls was significantly (P < 0.05) reduced by o-vanillin in a dose-dependent manner, while chitin was not markedly affected. Moreover, o-vanillin led to an increase in the permeability of cell membranes. o-Vanillin also exhibited a promising antifungal effect on contaminated corn kernels. Therefore, o-vanillin inhibited the growth of mycelia by disrupting the integrity of cell walls and cell membranes. This study not only sheds light on the antifungal mechanism of o-vanillin but also indicates that it is a promising agent for the control of A. flavus infection. KEY POINTS: • o-Vanillin has strong inhibitory effects on A. flavus. • o-Vanillin destroyed the integrity of cell walls and cell membranes. • o-Vanillin could effectively inhibit the growth of A. flavus on corn kernels.


Assuntos
Antifúngicos , Aspergillus flavus , Benzaldeídos , Membrana Celular , Parede Celular
8.
Neoplasma ; 68(1): 31-39, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32940042

RESUMO

The failure to treat and control the growth of metastases is the main cause of death in breast cancer (BC) patients. Compared to the traditional method of analyzing circulating tumor DNA (ctDNA), capturing intact circulating tumor cells (CTCs) allows us to more accurately characterize mutations and identify suitable targeted therapies. We used CellCollector to collect peripheral CTCs. Thirty metastatic breast cancer (MBC) patients were enrolled, and 17 were analyzed with next-generation sequencing (NGS) methods. Clinical characteristics were analyzed along with the CTCs enumeration and detection rates. Whole-genome amplification (WGA) was used to amplify the CTC genomic DNA of 127 genes. Patients younger than 45 years old, with brain metastasis, with three or more metastatic sites, or with HER2-positive had the highest number of CTCs collected. The CTCs detection rate was also correlated to the number of metastasis sites. Different metastasis sites such as the brain, viscus, bone, and soft tissue contained specific high-frequency gene mutations. AKT3, MYC, and NT5C2 mutations were only found in brain metastases. APC, BCL2L11, ESRP1, FLT3 mutations were only in the visceral metastases. KEAP1, KIT, MET were the specific mutation genes in patients with bone and soft tissue metastases. These findings provide evidence that we can detect gene mutation information for obtaining the biological characteristics by CTCs using CellCollector. Different metastasis sites contain specific high-frequency mutation genes, which provide guidance to the accurate gene therapy.


Assuntos
Neoplasias da Mama , Mutação , Células Neoplásicas Circulantes , Biomarcadores Tumorais/genética , Neoplasias da Mama/sangue , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Feminino , Humanos , Pessoa de Meia-Idade , Metástase Neoplásica
9.
Multivariate Behav Res ; 56(3): 496-513, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-32293929

RESUMO

Mediation analyses supply a principal lens to probe the pathways through which a treatment acts upon an outcome because they can dismantle and test the core components of treatments and test how these components function as a coordinated system or theory of action. Experimental evaluation of mediation effects in addition to total effects has become increasingly common but literature has developed only limited guidance on how to plan mediation studies with multi-tiered hierarchical or clustered structures. In this study, we provide methods for computing the power to detect mediation effects in three-level cluster-randomized designs that examine individual- (level one), intermediate- (level two) or cluster-level (level three) mediators. We assess the methods using a simulation and provide examples of a three-level clinic-randomized study (individuals nested within therapists nested within clinics) probing an individual-, intermediate- or cluster-level mediator using the R package PowerUpR and its Shiny application.


Assuntos
Modelos Estatísticos , Simulação por Computador , Interpretação Estatística de Dados , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto , Tamanho da Amostra
10.
Zhong Nan Da Xue Xue Bao Yi Xue Ban ; 46(7): 780-784, 2021 Jul 28.
Artigo em Inglês, Zh | MEDLINE | ID: mdl-34382597

RESUMO

Addison disease is rare, and it is rarer to coexist with systemic lupus erythematosus and antiphospholipid antibody syndrome. We hereby reported a middle-aged female who presented with nausea, vomit, skin and mucosa hyperpigmentation, hypotension, hyponatremia, and pulmonary infection after diagnosis of deep venous thrombosis of the left lower extremity and systemic lupus erythematosus in 2012. The patient was finally diagnosed with antiphospholipid antibody syndrome secondary to systemic lupus erythematosus with Addison disease after the examination, such as blood cortisol, adrenocorticotropic hormone rhythm, and antiphospholipid antibody, who was improved clinically after hormone, anti-infective, and anticoagulant treatment. The patient's condition was stable in the follow-up. In clinic, we should pay attention to adrenal damage in patients with connective tissue diseases such as systemic lupus erythematosus and antiphospholipid antibody syndrome, and be alert to the occurrence of adrenal crisis.


Assuntos
Doença de Addison , Síndrome Antifosfolipídica , Lúpus Eritematoso Sistêmico , Doença Aguda , Doença de Addison/complicações , Doença de Addison/diagnóstico , Síndrome Antifosfolipídica/complicações , Feminino , Humanos , Lúpus Eritematoso Sistêmico/complicações , Pessoa de Meia-Idade
11.
Zhong Nan Da Xue Xue Bao Yi Xue Ban ; 46(7): 704-710, 2021 Jul 28.
Artigo em Inglês, Zh | MEDLINE | ID: mdl-34382586

RESUMO

OBJECTIVES: To investigate the risk factors for serious infections among hospitalized systemic lupus erythematosus (SLE) patients, and to provide the advice for preventing serious infections in SLE patients. METHODS: Information of SLE patients hospitalized from March 2017 to February 2019 at the Department of Rheumatology and Immunology, Xiangya Hospital, Central South University was obtained. The patients were assigned into a serious infection group and a non-serious infection group. The risk factors for serious infections among SLE inpatients were identified by comparison between the 2 groups and multivariate logistic regression analysis. RESULTS: There were 463 SLE inpatients in total, and 144 were in the serious infection group and 319 in the non-serious infection group. Multivariate logistic regression analysis showed that age ≥54.50 years old (OR=4.958, P<0.001), cardiovascular involvement (OR=6.287, P<0.001), hematologic involvement (OR=2.643, P=0.003), serum albumin <20 g/L (OR=2.340, P=0.036), C-reaction protein (CRP)/erythrocyte sedimentation rate (ESR)≥0.12 (OR=2.430, P=0.002), glucocorticoid dose ≥8.75 mg/d prednisone-equivalent (OR=2.465, P=0.002), and the combined use of immunosuppressive agents (OR=2.847, P=0.037) were the risk factors for serious infections in SLE inpatients. CONCLUSIONS: SLE patients with older age, cardiovascular involvement, hematologic involvement, low serum albumin are prone to suffering serious infections. Increased CRP/ESR ratio indicates serious infections in SLE inpatients. High-dose glucocorticoid and the combined use of immunosuppressive agents can increase the risk of serious infections in SLE inpatients.


Assuntos
Pacientes Internados , Lúpus Eritematoso Sistêmico , Idoso , Glucocorticoides/efeitos adversos , Humanos , Lúpus Eritematoso Sistêmico/complicações , Pessoa de Meia-Idade , Prednisona , Fatores de Risco
12.
Qual Life Res ; 29(11): 3009-3015, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32564293

RESUMO

PURPOSE: Adverse events (AEs) assessment by clinicians is a standard practice in a clinical setting. However, studies have found clinicians tend to report fewer AEs, especially subjective AEs. We aimed to explore the difference of subjective AEs assessment between clinicians and patients based on PRO-CTCAE, and to discuss the necessity of incorporating patient into the evaluation of AEs. METHODS: Between April and July 2019, two different questionnaires with the same subjective AEs were given to patients and clinicians in the Day Chemotherapy ward of Breast Center in the Fourth Hospital of HeBei Medical University. Patients completed a Simplified Chinese version of PRO-CTCAE, including six common subjective AEs of chemotherapy: nausea, vomiting, diarrhea, fatigue, pain, and constipation. Clinicians completed the common terminology criteria for adverse events (CTCAE) with the same AEs. General information of enrolled patients and results from the questionnaires were collected and analyzed. RESULTS: 384 paired questionnaires were collected. Clinicians reported less subjective AEs than patients, and the general agreement between patients and clinicians was poor. When considering the grade difference, we utilize weighted kappa coefficient to analysis, and agreement between patients and clinicians was poor (k < 0.4) regardless of the frequency, the severity and interfering with daily life of AEs, and the most discrepancies were within one point. Patients tended to grade severer than the clinician. CONCLUSIONS: The results of this study showed that there were differences between clinicians and patients in subjective adverse events evaluation. Patient reporting of symptoms can be used as a supplementary method to incorporate the current approach to monitor subjective AEs, to improve the timeliness and accuracy of clinical evaluation of subjective AEs.


Assuntos
Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/diagnóstico , Medidas de Resultados Relatados pelo Paciente , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Qualidade de Vida , Inquéritos e Questionários , Adulto Jovem
13.
J Sci Food Agric ; 100(12): 4540-4548, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32400002

RESUMO

BACKGROUND: Cyromazine and acetamiprid are widely applied as pesticides in agriculture, causing increasing concerns about their residues in crops. In this study, cyromazine, acetamiprid and their mixture were applied to cowpea to investigate their degradation dynamics and perform a dietary risk assessment. RESULTS: The dissipation behavior of cyromazine and acetamiprid in the single- and mixed-pesticide groups followed first-order kinetics, with a linear correlation coefficient of 0.910 to 0.987. The half-lives of cyromazine and acetamiprid were 1.56-11.18 days in the four different matrices. The half-life of cyromazine in the mixed-pesticide group was similar to or even shorter than that in the single-pesticide group. The highest levels of cyromazine and acetamiprid in cowpea occurred with a preharvest interval of 7 days and after two or three applications. These levels are below the maximum residue limits recommended by the Chinese Ministry of Agriculture for cyromazine and acetamiprid in cowpea. The risk quotient of cyromazine and acetamiprid ranged from 0.0018 to 0.0418, and the national estimated short-term intake values of the cyromazine and acetamiprid were far below the acute reference dose as recommended by the European Food Safety Authority. CONCLUSION: These results suggest that the use of cyromazine and acetamiprid and a cyromazine-acetamiprid mixture in cowpea is safe under the Good Agricultural Practices for Chinese fields, and the use of a cyromazine-acetamiprid mixture affords even better results than the application of cyromazine alone. Moreover, the residue dynamics information will support the label claims for the application of cyromazine, acetamiprid and a cyromazine-acetamiprid mixture to cowpea fruit. © 2020 Society of Chemical Industry.


Assuntos
Neonicotinoides/química , Resíduos de Praguicidas/química , Poluentes do Solo/química , Triazinas/química , Vigna/química , Contaminação de Alimentos/análise , Cinética , Medição de Risco , Sementes/química , Solo/química
14.
Psychother Res ; 30(8): 1061-1074, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32036780

RESUMO

Objective: Analysis of the intermediate behaviors and mechanisms through which innovative therapies come to shape outcomes is a critical objective in many areas of psychotherapy research because it supports the iterative exploration, development and refinement of theories and therapies. Despite widespread interest in the intermediate behaviors and mechanisms that convey treatment effects, there is limited guidance on how to effectively and efficiently design studies to detect such mediated effects in the types of partially nested designs that commonly arise in psychotherapy research. In this study, we develop statistical power formulas to identify requisite sample sizes and guide the planning of studies probing mediation under two- and three-level partially nested designs. Method: We investigate multilevel mediation in partially nested structures and models for two- and three-level designs. Results: Well-powered studies probing mediation using partially nested designs will typically require moderate to large sample sizes or moderate to large effects. Discussion: We implement these formulas in the R package PowerUpR and a simple Shiny web application (https://poweruprshiny.shinyapps.io/PartiallyNestedMediationPower/) and demonstrate their use to plan studies using partially nested designs.


Assuntos
Interpretação Estatística de Dados , Modelos Estatísticos , Negociação , Psicoterapia , Humanos , Tamanho da Amostra , Resultado do Tratamento
15.
Bull Environ Contam Toxicol ; 104(1): 149-155, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31784766

RESUMO

This study was intended to develop an environment-friendly controlled release system for spirotetramat in an alginate matrix. Four formulations, starch-chitosan-calcium alginate (SCCA), starch-calcium alginate (SCA), chitosan-calcium alginate (CCA), and calcium alginate (CA) complex gel beads, were prepared by the extrusion-exogenous gelation method. The properties of the formulations were studied. The results showed that the release behaviors of the formulations in water could be well described by the logistic model, and the release occurred through Fickian diffusion. Among the four formulations, SCCA showed the highest entrapment efficiency, drug loading and the slowest release rate. Degradation studies revealed that the SCCA formulation exhibited an obvious slower degradation rate of spirotetramat in soils than the commercially available formulation. The estimated half-life of the SCCA formulation was 2.31, 3.25, and 4.51 days in waterloggogenic paddy soil, purplish soil, and montmorillonite, respectively, when the soils were moistened to 60% of its dry weight. This study provided a possible approach to prolong the duration of spirotetramat and to reduce environmental contamination.


Assuntos
Alginatos/química , Compostos Aza/química , Quitosana/química , Compostos de Espiro/química , Bentonita , Preparações de Ação Retardada , Ácido Glucurônico , Ácidos Hexurônicos , Amido
17.
Biotechnol Appl Biochem ; 66(6): 930-938, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31433514

RESUMO

Aflatoxin B1 (AFB1 ) removing bacterial strains were isolated from different habitats that were easily contaminated by AFB1 . Furthermore, the composition of the fermentation medium and conditions of fermentation process were optimized, including carbon source, nitrogen source, metal ions, temperature, initial pH value, inoculation volume, and culture broth volume. Using coumarin as the sole carbon and energy source, we primarily screened 31 strains, and 10 strains were found to be capable to remove AFB1 . Among them, the highest removal rate of 71.91% appeared in those isolated from rotten wood (poplar). Strains XY1, XY3, and T6 were carried out to identify, and the results were Klebsiella sp., Klebsiella pneumonia, and Pantoea sp., respectively. Corn cob powder and tryptone can significantly increase the AFB1 removal activity of these strains. The AFB1 removal activity of Klebsiella sp.XY1 and K. pneumonia XY3 can be enhanced by Ca2+ , and those of Pantoea sp. T6 can be enhanced by Cu2+ . Temperature and initial pH were positively correlated with the AFB1 removal activity of these strains in a certain range. This study not only provides reference for the screening and application of AFB1 removing bacteria, but also provides a basis for possible application in the food and feed industry.


Assuntos
Aflatoxina B1/isolamento & purificação , Aflatoxina B1/metabolismo , Fermentação , Klebsiella/química , Pantoea/química , Stenotrophomonas maltophilia/química , Aflatoxina B1/química , Klebsiella/metabolismo , Pantoea/metabolismo , Stenotrophomonas maltophilia/metabolismo
18.
J Sci Food Agric ; 99(10): 4725-4730, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-30920004

RESUMO

BACKGROUND: Since microcapsule technology has a good protective effect on unstable bioactive substances, many studies have focused on exploring the best technical conditions for forming microcapsules. Modified starch is a microcapsule wall material with good emulsifying and film-forming properties. The objective of this work was to study the creep-recovery behavior of modified starch pastes for various creep time, shear stress and temperature. Furthermore, the effect of creep-recovery behavior on the morphology of microcapsules made of the modified starch was investigated. RESULTS: The maximum creep compliance (Jmax ), instantaneous compliance (J0 ) and retardation compliance (J1 ) of modified starch increased proportionally with increasing creep time and shear stress but decreased with increasing temperature. The Newtonian viscosity (η0 ) increased with increasing creep time and temperature but decreased with increasing shear stress. The recovery rate of the modified starch pastes varied from 0.92 to 33.68% in the creep-recovery test conditions. Creep-recovery data could be well explained by a four-parameter Burgers model (R2 > 0.918). CONCLUSIONS: Modified starch pastes exhibited time-, stress- and temperature-dependent creep-recovery behavior. The Jmax values of modified starch pastes were low(<0.20 Pa-1 ) and the η0 values high (>3.5 × 103  Pa s) for all test conditions. The results revealed the modified starch pastes had a good rigid network structure to resist deformation but recovery was difficult once deformation occurred. Microcapsules produced using the modified starch exhibited a small deformation with regular spheres and some dents, consistent with the results of creep-recovery tests. © 2019 Society of Chemical Industry.


Assuntos
Amido/química , Cápsulas/química , Elasticidade , Reologia , Estresse Mecânico , Temperatura , Viscosidade
19.
Glycoconj J ; 35(6): 547-559, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30343348

RESUMO

In this study, four main components of feruloylated oligosaccharides (FOs),FOs-1, FOs-2, FOs-3 and FOs-4,were isolated from wheat bran by use of Amberlite XAD-2 and Sephadex LH-20. Structural characterization of FOs was determined by use of high performance liquid chromatography (HPLC), gas chromatography (GC) and fourier transform-infrared spectroscopy (FT-IR). Antioxidant properties were investigated in vitro. Average degrees of polymerization (DP) of the four components (FOs-1, FOs-2, FOs-3 and FOs-4) were approximately 10.6, 7.7, 6.1 and 3.4, respectively. In addition, DP were consistent with molar ratios of arabinose and xylose in 1:9.46, 1:5.30, 1:2.91 and 1:0.19, respectively. The presence of ß-glycosidic linkage was confirmed at 896 cm - 1 by use of FT-IR. In vitro antioxidant studies demonstrated that FOs-1, FOs-2, FOs-3 and FOs-4 possessed significant antioxidant activities in the dose-dependent manner. In addition, the degree of polymerization affected antioxidant capacity. These results have improved our understanding of the relationship between FOs with different structural types and their antioxidant activities.


Assuntos
Antioxidantes/análise , Ácidos Cumáricos/análise , Fibras na Dieta/análise , Oligossacarídeos/análise , Polimerização , Compostos de Bifenilo/química , Quelantes/farmacologia , Cromatografia Líquida de Alta Pressão , Ácidos Cumáricos/química , Sequestradores de Radicais Livres/química , Radical Hidroxila/química , Íons , Metais/isolamento & purificação , Oligossacarídeos/química , Oligossacarídeos/isolamento & purificação , Picratos/química , Padrões de Referência , Espectroscopia de Infravermelho com Transformada de Fourier , Superóxidos/química
20.
Ecotoxicol Environ Saf ; 152: 8-15, 2018 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-29355773

RESUMO

The levels of 16 US EPA priority polycyclic aromatic hydrocarbons (PAHs) were investigated in corals, ambient seawater and sediments of Hainan Island, China, using gas chromatography - mass spectrometry (GC-MS). The total PAHs (∑PAHs) concentrations ranged from 273.79 to 407.82ng/L in seawater. Besides, the concentrations of ∑PAHs in corals 333.88-727.03ng/g dw) were markedly (P < 0.05) higher than ambient sediments 67.29-196.99ng/g dw), demonstrating the bioaccumulation ability of PAHs by corals. The highest concentration of ∑PAHs was detected at site S2 in Pavona decussate, which also bore the highest ∑PAHs levels in both seawater and sediments. The massive corals were more enriched with PAHs than the branching corals. Although 2 and 3-ring PAHs were predominant and accounted for 69.27-80.46% of the ∑PAHs in corals and ambient environment, the levels of high molecular weight (HMW) PAHs (4-6 ring) in corals also demonstrated their potential dangers for corals and organisms around coral reefs. Biota-sediment accumulation factor (BSAF) refers to an index of the pollutant absorbed by aquatic organisms from the surrounding sediments. The poor correlation between log BSAF and log Kow (hydrophobicity) indicated that PAHs in corals maybe not bioaccumulate from the ambient sediments but through pathways like absorbing from seawater, symbiosis, and feeding. Based on our data, long-term ecological monitoring in typical coral reef ecosystems combined with ecotoxicological tests of PAHs on corals is necessary to determine the impacts of PAHs on coral reefs.


Assuntos
Antozoários/química , Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Hidrocarbonetos Policíclicos Aromáticos/análise , Água do Mar/química , Poluentes Químicos da Água/análise , Animais , Biota , China , Ecossistema , Cromatografia Gasosa-Espectrometria de Massas , Ilhas
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA