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1.
Neurosci Lett ; 822: 137648, 2024 Feb 06.
Artículo en Inglés | MEDLINE | ID: mdl-38246407

RESUMEN

Converging evidence from behavioral and neuroscience studies demonstrated that our attention to the external world is influenced by emotion, especially anxiety. However, little is known about how trait anxiety influences neural and behavioral responses during mind wandering. The present study aimed to examine the neural and cognitive time courses of how trait anxiety affects mind wandering. Event-related potentials (ERPs) were recorded from 20 individuals with high trait anxiety and 20 with low trait anxiety when they performed the Sustained Attention to Response Task (SART) in which they were asked to respond to frequent ''nontargets'' (digits 0-6, 8-9) but withhold responses to infrequent ''targets'' (the digit 7). We compared the behavioral performance and electroencephalographic waves between the high and low trait anxiety groups during states of "mind wandering" (fail to withhold a response to the target number) and being "on-task" (correctly withhold a response to the target number). Results showed that a larger late positive component (LPC, 400-950 ms) was elicited when participants were "on task" than when they were mind wandering. Additionally, a larger late slow waveform (LSW, 950-1050 ms) was elicited in the high trait anxiety group than in the low trait anxiety group. Moreover, there was a positive correlation between self-reported trait anxiety scores and the LSW amplitudes during mind wandering. It was proposed that the effect of trait anxiety on the cognitive neural mechanism underlying attentional processing was primarily reflected in a later process involving the redistribution of cognitive resources.


Asunto(s)
Electroencefalografía , Potenciales Evocados , Humanos , Trastornos de Ansiedad , Cognición/fisiología , Ansiedad
2.
Front Hum Neurosci ; 16: 919499, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35693541

RESUMEN

Developmental and neuroscience works have demonstrated that the moral judgment is influenced by theory of mind (ToM), which refers to the ability to represent the mental states of different agents. However, the neural and cognitive time course of interactions between moral judgment and ToM remains unclear. The present event-related potential (ERP) study investigated the underlying neural substrate of the interaction between moral judgment and ToM by contrasting the ERPs elicited by moral judgments for self and for others in moral dilemmas. In classic moral dilemmas, the agents must choose between the utilitarian choice (taking the action to kill or harm an innocent person but saving more people) and the non-utilitarian choice (taking no action to kill or harm the innocent person but letting some people die). The ERPs were recorded from participants who made moral judgments for self and for others when the agent made utilitarian or non-utilitarian choices during the dilemma. The results revealed that the moral judgment for others elicited a larger frontal late positive component (LPC, 500-900 ms) than that for self when the agents made utilitarian choices, while no difference was observed on early components of N1, P2, and N2. Moreover, individual differences in mentalizing ability were negatively correlated with the LPC amplitudes. These findings suggested that ToM modulated the late controlled process but not the early automatic process during moral judgments.

3.
J Hazard Mater ; 436: 129127, 2022 08 15.
Artículo en Inglés | MEDLINE | ID: mdl-35580496

RESUMEN

Selenium (Se) removal from contaminated water has become a major environmental problem in recent years. Designing efficient and selective materials for selenium adsorption is urgent and still represents a great challenge. Herein, two novel cationic covalent triazine frameworks (CTFS-Cl and CTFL-Cl) are developed for the first time and employed as a new class of Se adsorbents. The results from systematic adsorption experiments indicate that these materials can adsorb SeO42- in a wide range of pH values (2-11) with fast kinetics (5 min), outstanding adsorption capacity, and excellent selectivity over other competing anions. The maximum adsorption capacity achieved (149.3 mg/g by CTFS-Cl) constitutes one of the highest values among the organic polymeric materials. More importantly, after a single step adsorption, these materials can reduce the Se concentrations to lower than 10 µg/L, the lowest drinking water standard in the world. The adsorption mechanism was probed by XPS technique, EDS analysis, adsorption experiments, and DFT calculations, which reveals that anion exchange between Cl- and SeO42- is the main driving force for Se adsorption. Additionally, CTFS-Cl and CTFL-Cl perform well toward real contaminated river water sample with the residual Se being less than 8.49 µg/L. This work demonstrates the excellent performance of CTFs-based materials with great application prospect for Se removal in contaminated water treatment.


Asunto(s)
Selenio , Contaminantes Químicos del Agua , Purificación del Agua , Adsorción , Aniones , Polímeros , Ácido Selénico , Triazinas/análisis , Contaminantes Químicos del Agua/análisis , Purificación del Agua/métodos
4.
Medicine (Baltimore) ; 100(10): e24418, 2021 Mar 12.
Artículo en Inglés | MEDLINE | ID: mdl-33725820

RESUMEN

BACKGROUND: Chronic hand eczema (CHE) is a recurrent, frequently disabling skin condition that requires daily skin care to prevent transepidermal water loss, posing a significant burden of society and economy. In recent years, topical 0.05% clobetasol cream is widely used for the treatment of CHE for its efficacy, tolerability and safety. Whereas, no systematic review and meta-analysis has been updated up to now. Therefore, this work aims to assess the effectiveness and safety of topical 0.05% clobetasol cream in patients with CHE. METHODS: Study on topical 0.05% clobetasol cream for CHE will be searched from their inception to December, 2020 with the language restrictions of English and Chinese in 8 databases (PubMed, Cochrane Library, Embase, the web of science, VIP, CNKI, CBM, and WAN FANG). According to the heterogeneity test, a fixed or random-effect model will be used to synthesize data. The primary outcome is the proportion of patients achieving more than 75% reduction in signs and symptoms according to the Hand Eczema Severity Index (HECSI). The secondary outcomes include: scored for 4 different characteristics of the lesions (redness, scaling, lichenification, and pruritus), QoL questionnaire, adverse events, and recurrence events. STATA 13.0 and Review Manager software 5.3 will be used for analysis and synthesis. Two or more reviewers will independently conduct the selection of studies, data extraction, and data analysis. RESULTS: The results of the study expect to provide a high-quality, evidence-based recommendation on topical 0.05% clobetasol cream in the treatment of CHE for clinicians. CONCLUSION: The study will provide scientific and useful evidence for better use of topical 0.05% clobetasol cream in treating CHE. ETHICS AND DISSEMINATION: This study is a protocol for an overview of SRs/MAs that did not involve individual data. Thus, ethical approval is not required. OSF REGISTRATION NUMBER: DOI 10.17605/OSF.IO/SPHVZ.


Asunto(s)
Clobetasol/administración & dosificación , Eccema/tratamiento farmacológico , Dermatosis de la Mano/tratamiento farmacológico , Prurito/tratamiento farmacológico , Crema para la Piel/administración & dosificación , Enfermedad Crónica/tratamiento farmacológico , Clobetasol/efectos adversos , Eccema/complicaciones , Eccema/diagnóstico , Dermatosis de la Mano/complicaciones , Dermatosis de la Mano/diagnóstico , Humanos , Metaanálisis como Asunto , Prurito/diagnóstico , Prurito/etiología , Calidad de Vida , Ensayos Clínicos Controlados Aleatorios como Asunto , Índice de Severidad de la Enfermedad , Crema para la Piel/efectos adversos , Revisiones Sistemáticas como Asunto , Resultado del Tratamiento
5.
Medicine (Baltimore) ; 99(40): e22586, 2020 Oct 02.
Artículo en Inglés | MEDLINE | ID: mdl-33019475

RESUMEN

BACKGROUND: Neurodermatitis is a common inflammatory and allergic disease, characterized by itching and lichenification plaque. Some studies have reported cupping therapy (CT) for the treatment of neurodermatitis. However, the effectiveness and safety are still uncertain. This study aims to evaluate the efficacy and safety of CT for the treatment of patients with neurodermatitis. METHODS: We will retrieve the following electronic databases systematically: Pubmed, Web of Science, Embase, the Cochrane Library, Chinese Scientific Journal Database, China National Knowledge Infrastructure Database, Chinese Biomedical Literature Database, and Wanfang database from their inception to December 2020. Other literature resources will be manually searched. Published randomized controlled trials (RCTs) and quasi-randomized controlled trials (q-RCTs) on the topic will be retrieved by 2 investigators independently. We will apply a fixed-effect model or random effect model basis on the heterogeneity test and employ with RevMan 5.3 software for data synthesis. The total clinical effective rate will be selected as the primary outcome, skin disease quality of life index score, recurrence rate, and adverse events as secondary outcomes. RESULTS: This study will comprehensively summarize the high-quality trials to determine the efficacy and safety of CT for the treatment of patients with neurodermatitis. CONCLUSION: Our systematic review will present evidence for the efficacy and safety of CT to neurodermatitis patients. OSF REGISTRATION NUMBER: DOI 10.17605/OSF.IO/6DCM3.


Asunto(s)
Ventosaterapia/métodos , Medicina Tradicional China/métodos , Neurodermatitis/terapia , Prurito/etiología , Protocolos Clínicos , Ventosaterapia/efectos adversos , Femenino , Humanos , Erupciones Liquenoides/etiología , Erupciones Liquenoides/patología , Masculino , Medicina Tradicional China/efectos adversos , Neurodermatitis/patología , Neurodermatitis/psicología , Calidad de Vida , Ensayos Clínicos Controlados Aleatorios como Asunto , Seguridad , Resultado del Tratamiento , Metaanálisis como Asunto
6.
Medicine (Baltimore) ; 99(33): e21266, 2020 Aug 14.
Artículo en Inglés | MEDLINE | ID: mdl-32871985

RESUMEN

Chronic spontaneous urticaria (CSU) is a common dermatologic disease that seriously affects patient quality of life. The choice of therapy to control the disease and prevent its recurrence has always presented a difficult clinical issue. Previous studies have shown that traditional Chinese medicine is a safe and effective treatment for CSU. Recently, the temporal rhythms of CSU, a disease characterized by intermittent flares of active disease and periods of little or no disease, have attracted the attention of traditional Chinese medicine researchers. We designed a multicenter, randomized, controlled study to evaluate the efficacy and safety of combining a Chinese herbal formulation with acupuncture using shu-stream acupoints applied on the corresponding time meridians during disease exacerbations. We plan to recruit 111 outpatients with CSU aged 18 to 65 years. Participants will be randomized to 1 of the 3 groups: group A, which will be given basic acupuncture and the herbal formulation dangui yinzi; group B, which will be given danggui yinzi and shu-stream acupuncture; and a control group, which will be given danggui yinzi alone. Patients will be treated for 4 weeks and followed for 8 additional weeks. Investigators will evaluate the following parameters: the symptoms and side effects of treatment, quality of life (using the chronic urticaria quality of life questionnaire), and overall patient condition. Each week, patients will also complete the measurement of 7-day urticarial activity score. This is the first use of a combination of shu-stream acupoints and Chinese herbal medicine in the treatment of CSU. If successful, it will prove to be a simple, inexpensive, treatment strategy for solving a difficult clinical problem.


Asunto(s)
Terapia por Acupuntura , Urticaria Crónica/terapia , Fármacos Dermatológicos/uso terapéutico , Medicamentos Herbarios Chinos/uso terapéutico , Medicina Tradicional China , Ensayos Clínicos Controlados Aleatorios como Asunto , Puntos de Acupuntura , Terapia por Acupuntura/efectos adversos , Terapia por Acupuntura/métodos , Adolescente , Adulto , Anciano , Atención Ambulatoria , Terapia Combinada , Fármacos Dermatológicos/efectos adversos , Medicamentos Herbarios Chinos/efectos adversos , Humanos , Medicina Tradicional China/efectos adversos , Medicina Tradicional China/métodos , Persona de Mediana Edad , Selección de Paciente , Resultado del Tratamiento , Adulto Joven
7.
Medicine (Baltimore) ; 99(36): e22014, 2020 Sep 04.
Artículo en Inglés | MEDLINE | ID: mdl-32899053

RESUMEN

BACKGROUND: The pathogenesis of chronic spontaneous urticaria (CSU) is not clear, but its occurrence is closely related to the immune state of the body, that is, the balance of T cell subsets. Previous studies have confirmed that the dynamic imbalance of Th1/Th2 cells in CD4+T cell subsets of T cell subsets is closely related to the pathogenesis of CSU, but there are few studies on the relationship between the dynamic imbalance of Th17/Treg cells in CD4+T cell subsets and the pathogenesis of CSU. The purpose of this study is to evaluate the relationship between Th17/Treg cells expression in peripheral blood and CSU, so as to provide a reference basis for the pathogenesis of CSU. METHODS: PubMed, Embase, CENTRAL, Web of Science, China Biology Medicine Database, China National Knowledge Database, Wan Fang Database, and Chongqing VIP Database will be searched to collect case-control studies and cohort studies evaluating the relationship between Th17/Treg cells expression in peripheral blood and CSU. The search time limits will be from the establishment of the database to December 2020. The meta-analysis will be carried out with the RevMan V.5.3 statistical software. The quality of all included studies will be evaluated by the Newcastle-Ottawa scale. RESULTS: The results of this study will comprehensively evaluate the Th17/Treg cells expression levels in peripheral blood of patients with CSU, and provide a reference basis for the pathogenesis of CSU. CONCLUSION: The findings of this study may provide new evidence for the relationship between Th17/Treg cells balance in peripheral blood and CSU. OSF REGISTRATION NUMBER: DOI 10.17605/OSF.IO/S8MYW.


Asunto(s)
Urticaria Crónica/inmunología , Linfocitos T Reguladores/fisiología , Células Th17/fisiología , Humanos , Metaanálisis como Asunto , Revisiones Sistemáticas como Asunto
8.
Medicine (Baltimore) ; 99(39): e22400, 2020 Sep 25.
Artículo en Inglés | MEDLINE | ID: mdl-32991465

RESUMEN

BACKGROUND: Psoriasis is a chronic recurrent dermatological disease that patents always suffer from different comorbidities. Chinese herbal medicine (CHM) has been commonly used in the treatment of psoriasis for a long history. Previous systematic reviews (SRs)/meta-analyses (MAs) have shown that CHM may benefit patients with psoriasis. This overview aims to summarize the evidence from published SRs/MAs for clinical application and to provide several directions for future researches. METHODS: Nine electronic databases (Medline, Embase, Cochrane Library, AMED, CINAHL, CBM, CNKI, VIP Database, Wanfang Databases) will be searched from their inceptions to September 2020 without language restrictions. At least 2 reviewers will independently conduct the study selection, data extraction, and quality assessment. The methodological quality, risk of bias, reporting quality, and evidence quality will be respectively evaluated by the Assessing the Methodological Quality of Systematic Reviews 2 (AMSTAR 2), the Risk of Bias in Systematic Reviews, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), and the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system. RESULTS: The results of this overview will be submitted to a peer-reviewed journal for publication. CONCLUSIONS: We expect to compile current evidence from published SRs/MAs of CHM for patients with psoriasis in an accessible and useful document. ETHICS AND DISSEMINATION: This study is a protocol for an overview of SRs/MAs that did not involve individual data. Thus, ethical approval is not required. OSF REGISTRATION NUMBER: DOI 10.17605/OSF.IO/VC654.


Asunto(s)
Medicina Tradicional China/métodos , Psoriasis/terapia , Enfermedad Crónica , Humanos , Medicina Tradicional China/efectos adversos , Metaanálisis como Asunto , Proyectos de Investigación , Revisiones Sistemáticas como Asunto
9.
Medicine (Baltimore) ; 99(21): e20488, 2020 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-32481354

RESUMEN

BACKGROUND: Psoriasis is a common, chronic, and recurrent skin inflammatory disease, with psoriasis vulgaris considered as the most prevalent type of psoriasis. Chinese herbal bath, a type of traditional Chinese medicine, is an external therapy widely used to treat psoriasis vulgaris in China, and it has achieved satisfactory clinical effects. However, there are few studies evaluating the safety and efficacy of Chinese herbal bath compared with other external therapies administered under similar conditions. The purpose of this study is to comprehensively evaluate the clinical safety and efficacy of Chinese herbal bath in the treatment of psoriasis vulgaris through a systematic evaluation of the literature, so as to provide a reference basis for future clinical applications. METHODS: PubMed, Embase, CENTRAL, the Web of Science, the China Biology Medicine Database (CBM), the China National Knowledge Database (CNKI), the Wan Fang Database, and the Chong Qing VIP Database will be searched to collect randomized controlled trials of Chinese herbal bath used to treat psoriasis vulgaris. The search time limits will be from the establishment of the database to December 2019. Two researchers will independently screen the studies, extract data, and evaluate the risk of bias of the studies. Meta-analysis will be carried out with the RevMan5.3 software. The mean difference will be used as the effect index for the measurement data, and the odds ratio will be used as the effect index for the enumeration data. The 95% confidence interval will be provided for each effect. Heterogeneity among the results of each study will be evaluated by the Chi-square test. RESULTS: This study will comprehensively evaluate the clinical safety and efficacy of Chinese herbal bath in the treatment of psoriasis vulgaris, so as to provide a reference basis for future clinical applications. CONCLUSION: This study will provide a theoretical basis for the standardized administration of Chinese herbal bath. OSF REGISTRATION NUMBER:: doi: 10.17605/OSF.IO/4HRPJ.


Asunto(s)
Baños/normas , Medicina de Hierbas/normas , Psoriasis/terapia , Baños/métodos , China , Protocolos Clínicos , Medicina de Hierbas/métodos , Humanos , Medicina Tradicional China/métodos , Medicina Tradicional China/normas , Metaanálisis como Asunto , Psoriasis/fisiopatología , Revisiones Sistemáticas como Asunto
10.
Medicine (Baltimore) ; 99(19): e20172, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32384509

RESUMEN

BACKGROUND: Chinese herbal bath has long been used in the curative treatment of psoriasis vulgaris. However, there is no unified standard protocol for Chinese herbal bath. Many factors affect the curative effect of Chinese herbal bath, such as water temperature, bath concentration, and soaking time. Most studies involving Chinese herbal bath has described the bath generally, and few studies have investigated the factors that might contribute to the efficacy of Chinese herbal bath. Here we describe a protocol to evaluate the efficacy and safety of various bathwater temperatures and herbal concentrations on psoriasis vulgaris, and their effect on serum vascular endothelial growth factor (VEGF), tumor necrosis factor α (TNF-α), interleukin 23 (IL-23), and interleukin 17 (IL-17). These data could be useful for optimizing Chinese herbal bath treatments. METHODS: In this randomized controlled trial, we planned to recruit 288 hospitalized atients with psoriasis vulgaris aged 18 to 65 years. All participants who meet the inclusion criteria will be randomly assigned to the observation group, the control group, or the basic treatment group. The observation group will be divided into 6 sub-groups according to water temperatures and bath concentrations, designated as observation groups 1 to 6. Thirty-six participants will be assigned to each group. The basic treatment group will be given co-qingdai capsule, po 2 g tid; compound glycyrrhizin tablet, po 75 mg tid; AA Skincare jojoba Oil, us.ext qd. The observation group will be given a Chinese herbal bath at the same time as the basic treatment. The control group will be given ozone hydrotherapy at the same time as the basic treatment. The entire treatment course will last for 2 weeks. The following parameters will be compared in each group, before and 2 weeks after treatment: the psoriasis area and severity index score (PASI), pruritus score, clinical efficacy, and dermatology life quality index score (DLQI); serum levels of serum VEGF, TNF-α, IL-23, and IL-17; and confocal laser scanning microscope images. CONCLUSION: This study will evaluate the efficacy and safety of various Chinese herbal bath conditions (water temperatures and herbal concentrations) on the treatment of psoriasis vulgaris, which will provide an important reference for the operation of Chinese herbal bath. TRIAL REGISTRATION NUMBER: ChiCTR1900027468.


Asunto(s)
Citocinas/efectos de los fármacos , Medicamentos Herbarios Chinos/uso terapéutico , Medicina Tradicional China/métodos , Psoriasis/terapia , Factor A de Crecimiento Endotelial Vascular/efectos de los fármacos , Adolescente , Adulto , Anciano , Terapia Combinada , Relación Dosis-Respuesta a Droga , Método Doble Ciego , Medicamentos Herbarios Chinos/administración & dosificación , Medicamentos Herbarios Chinos/efectos adversos , Femenino , Ácido Glicirrínico/uso terapéutico , Humanos , Masculino , Medicina Tradicional China/efectos adversos , Persona de Mediana Edad , Temperatura , Factores de Tiempo , Adulto Joven
11.
Medicine (Baltimore) ; 99(20): e20348, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32443388

RESUMEN

BACKGROUND: Psoriasis vulgaris (PV) is a chronic, immune-mediated dermatological disease that significantly affects the patient's health and quality of life. At present, cupping has been widely used in the treatment of psoriasis. However, the effectiveness and safety of cupping in patients with PV are still controversial. Therefore, this review aims to evaluate the efficacy and safety of cupping therapy on PV. METHODS: The following databases will be searched from their inceptions to April 2020 with a language limitation of English and Chinese: Pubmed, Medline, Embase, Cochrane Central Register of Controlled Trials, Chinese Biomedical Literature Databas, China National Knowledge Infrastructure Database, Wanfang database and Chinese Scientific Journal Database. The reference lists of eligible studies and other resources will also be searched. Two researchers will independently perform the selection of studies, data extraction, and data analysis. A fixed or random-effect model will be applied to synthesize data depend on the heterogeneity test. The primary outcome is the proportion of patients achieving at least a 60% improvement in psoriasis area and severity index (PASI) score from baseline (PASI 60). Secondary outcomes include the proportion of patients achieving at least a 90% improvement in PASI score from baseline (PASI 90), the mean change of PASI and dermatology life quality index score, the itching index, adverse events, and recurrence rate. RevMan V.5.3 software will be used for meta-analysis. RESULTS: The study will provide a high-quality evidence-based review of cupping for PV. CONCLUSIONS: The study will be conducted to evaluate the efficacy and safety of cupping in the treatment of PV and supposed to provide clear evidence for the clinical application of cupping therapy. ETHICS AND DISSEMINATION: As the study is a protocol of systematic review and meta-analysis that does not involve individual data, ethical approval will not be required. The results will be published in a peer-reviewed journal. OSF REGISTRATION NUMBER: DOI 10.17605/OSF.IO/KV4CJ.


Asunto(s)
Ventosaterapia/métodos , Psoriasis/terapia , Enfermedad Crónica , Terapia Combinada , Ventosaterapia/efectos adversos , Humanos , Calidad de Vida , Ensayos Clínicos Controlados Aleatorios como Asunto , Proyectos de Investigación , Metaanálisis como Asunto
12.
Diagnostics (Basel) ; 9(3)2019 Jul 13.
Artículo en Inglés | MEDLINE | ID: mdl-31337082

RESUMEN

Barcode technology has a broad spectrum of applications including healthcare, food security, and environmental monitoring, due to its ability to encode large amounts of information. With the rapid development of modern molecular research, barcodes are utilized as a reporter with different molecular combinations to label many biomolecular targets, including genomic and metabolic elements, even with multiplex targeting. Along with the advancements in barcoded bioassay, the improvements of various designs of barcode components, encoding and decoding strategies, and their portable adoption are indispensable in satisfying multiple purposes, such as medical confirmation and point-of-care (POC) testing. This perspective briefly discusses the current direction and progress of barcodes development and provides a hypothesis for barcoded bioassay in the near future.

13.
J Org Chem ; 84(7): 3960-3967, 2019 04 05.
Artículo en Inglés | MEDLINE | ID: mdl-30834752

RESUMEN

A new strategy is presented to preclude aggregation and enhance water solubility of cyanine dyes. Namely, a heteroatom-containing substituent, for distorting molecular plane and increasing interaction with water molecules, is introduced to the methine chain of 2-thiazole orange (1, a monocyanine) via one-step, and 2-thiazole orange derivatives 2a-g are prepared accordingly. The X-ray crystal structures show that the molecular plane of 2a-g is drastically twisted, which reduces intermolecular π-π stacking. The derivatives 2a-g exhibit good to excellent water solubility and can be dissolved in aqueous phosphate-buffered saline (PBS) at concentrations suitable for biomedical applications. No aggregation in aqueous PBS, relatively high molar extinction coefficients, and low solvatochromism of 2a-g are reflected by the UV-vis spectra. Compound 2b shows fast response and high selectivity for biothiols (Cys, Hcy, and GSH) in aqueous PBS and is further employed to detect endogenous biothiols with decent biocompatibility as demonstrated by live cell fluorescence imaging.


Asunto(s)
Benzotiazoles/química , Quinolinas/química , Aminoácidos/análisis , Aminoácidos/química , Benzotiazoles/síntesis química , Tampones (Química) , Cristalografía por Rayos X , Colorantes Fluorescentes/química , Quinolinas/síntesis química , Solubilidad , Espectrofotometría Ultravioleta , Relación Estructura-Actividad , Agua/química
14.
Chem Commun (Camb) ; 55(27): 3879-3882, 2019 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-30806442

RESUMEN

Herein, a one-pot, two-step procedure for the diastereoselective synthesis of cyclopropanes bearing trifluoromethyl-substituted all-carbon quaternary centers has been described. Trifluoromethyl-activated 1,3-enynes undergo cyclopropanation reactions with sulfur ylides under mild reaction conditions without fluoride elimination, which affords the cis-isomer mainly. Interestingly, a sequential TBAF-mediated deprotection of the triisopropylsilyl group results in a diastereoenriched epimerization which gives rise to the trans-cyclopropanes as the sole isomers.

15.
Org Lett ; 20(1): 60-63, 2018 01 05.
Artículo en Inglés | MEDLINE | ID: mdl-29215293

RESUMEN

The D-π-A methine chain electrophilic substitution reactions for directly introducing some functional groups to the dipole conjugate chain, with mild conditions and good yields, are disclosed. This method is shown to efficiently replace the hydrogen on the D-π-A methine chain with an electrophile to synthesize methine-substituted Cy3.5 in one step.

16.
Phys Rev Lett ; 119(13): 138102, 2017 Sep 29.
Artículo en Inglés | MEDLINE | ID: mdl-29341672

RESUMEN

Single-molecule Förster resonance energy transfer is widely applied to study helicases by detecting distance changes between a pair of dyes anchored to overhangs of a forked DNA. However, it has been lacking single-base pair (1-bp) resolution required for revealing stepping kinetics of helicases. We designed a nanotensioner in which a short DNA is bent to exert force on the overhangs, just as in optical or magnetic tweezers. The strategy improved the resolution of Förster resonance energy transfer to 0.5 bp, high enough to uncover differences in DNA unwinding by yeast Pif1 and E. coli RecQ whose unwinding behaviors cannot be differentiated by currently practiced methods. We found that Pif1 exhibits 1-bp-stepping kinetics, while RecQ breaks 1 bp at a time but sequesters the nascent nucleotides and releases them randomly. The high-resolution data allowed us to propose a three-parameter model to quantitatively interpret the apparently different unwinding behaviors of the two helicases which belong to two superfamilies.


Asunto(s)
ADN Helicasas/metabolismo , ADN/química , Escherichia coli/metabolismo , Transferencia Resonante de Energía de Fluorescencia , Cinética , Conformación de Ácido Nucleico
17.
Nucleic Acids Res ; 44(9): 4330-9, 2016 05 19.
Artículo en Inglés | MEDLINE | ID: mdl-27098034

RESUMEN

Pif1 is a prototypical member of the 5' to 3' DNA helicase family conserved from bacteria to human. It has a high binding affinity for DNA, but unwinds double-stranded DNA (dsDNA) with a low processivity. Efficient DNA unwinding has been observed only at high protein concentrations that favor dimerization of Pif1. In this research, we used single-molecule fluorescence resonance energy transfer (smFRET) and magnetic tweezers (MT) to study the DNA unwinding activity of Saccharomyces cerevisiae Pif1 (Pif1) under different forces exerted on the tails of a forked dsDNA. We found that Pif1 can unwind the forked DNA repetitively for many unwinding-rezipping cycles at zero force. However, Pif1 was found to have a very limited processivity in each cycle because it loosened its strong association with the tracking strand readily, which explains why Pif1 cannot be observed to unwind DNA efficiently in bulk assays at low protein concentrations. The force enhanced the unwinding rate and the total unwinding length of Pif1 significantly. With a force of 9 pN, the rate and length were enhanced by more than 3- and 20-fold, respectively. Our results imply that the DNA unwinding activity of Pif1 can be regulated by force. The relevance of this characteristic of Pif1 to its cellular functions is discussed.


Asunto(s)
ADN Helicasas/química , Proteínas de Saccharomyces cerevisiae/química , Adenosina Trifosfato/química , ADN de Hongos/química , Cinética , Saccharomyces cerevisiae/enzimología
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