Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 279
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Nano Lett ; 24(13): 3866-3873, 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38442405

RESUMO

The low wear resistance of macroscale graphene coatings does not match the ultrahigh mechanical strength and chemical inertness of the graphene layer itself; however, the wear mechanism responsible for this issue at low mechanical stress is still unclear. Here, we demonstrate that the susceptibility of the graphene monolayer to wear at its atomic step edges is governed by the mechanochemistry of frictional interfaces. The mechanochemical reactions activated by chemically active SiO2 microspheres result in atomic attrition rather than mechanical damage such as surface fracture and folding by chemically inert diamond tools. Correspondingly, the threshold contact stress for graphene edge wear decreases more than 30 times to the MPa level, and mechanochemical wear can be described well with the mechanically assisted Arrhenius-type kinetic model, i.e., exponential dependence of the removal rate on the contact stress. These findings provide a strategy for improving the antiwear of graphene-based materials by reducing the mechanochemical interactions at tribological interfaces.

2.
Proc Natl Acad Sci U S A ; 118(46)2021 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-34772810

RESUMO

We generalize Taylor's law for the variance of light-tailed distributions to many sample statistics of heavy-tailed distributions with tail index α in (0, 1), which have infinite mean. We show that, as the sample size increases, the sample upper and lower semivariances, the sample higher moments, the skewness, and the kurtosis of a random sample from such a law increase asymptotically in direct proportion to a power of the sample mean. Specifically, the lower sample semivariance asymptotically scales in proportion to the sample mean raised to the power 2, while the upper sample semivariance asymptotically scales in proportion to the sample mean raised to the power [Formula: see text] The local upper sample semivariance (counting only observations that exceed the sample mean) asymptotically scales in proportion to the sample mean raised to the power [Formula: see text] These and additional scaling laws characterize the asymptotic behavior of commonly used measures of the risk-adjusted performance of investments, such as the Sortino ratio, the Sharpe ratio, the Omega index, the upside potential ratio, and the Farinelli-Tibiletti ratio, when returns follow a heavy-tailed nonnegative distribution. Such power-law scaling relationships are known in ecology as Taylor's law and in physics as fluctuation scaling. We find the asymptotic distribution and moments of the number of observations exceeding the sample mean. We propose estimators of α based on these scaling laws and the number of observations exceeding the sample mean and compare these estimators with some prior estimators of α.

3.
Ecotoxicol Environ Saf ; 277: 116368, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38669874

RESUMO

Perfluorooctane sulfonate (PFOS) is a persistent chemical that has long been a threat to human health. However, the molecular effects of PFOS on various organs are not well studied. In this study, male Sprague-Dawley rats were treated with various doses of PFOS through gavage for 21 days. Subsequently, the liver, lung, heart, kidney, pancreas, testis, and serum of the rats were harvested for lipid analysis. We applied a focusing lipidomic analytical strategy to identify key lipid responses of phosphorylcholine-containing lipids, including phosphatidylcholines and sphingomyelins. Partial least squares discriminant analysis revealed that the organs most influenced by PFOS exposure were the liver, kidney, and testis. Changes in the lipid profiles of the rats indicated that after exposure, levels of diacyl-phosphatidylcholines and 22:6-containing phosphatidylcholines in the liver, kidney, and testis of the rats decreased, whereas the level of 20:3-containing phosphatidylcholines increased. Furthermore, levels of polyunsaturated fatty acids-containing plasmenylcholines decreased. Changes in sphingomyelin levels indicated organ-dependent responses. Decreased levels of sphingomyelins in the liver, nonmonotonic dose responses in the kidney, and irregular responses in the testis after PFOS exposure are observed. These lipid responses may be associated with alterations pertaining to phosphatidylcholine synthesis, fatty acid metabolism, membrane properties, and oxidative stress in the liver, kidney, and testis. Lipid responses in the liver could have contributed to the observed increase in liver to body weight ratios. The findings suggest potential toxicity and possible mechanisms associated with PFOS in multiple organs.


Assuntos
Ácidos Alcanossulfônicos , Fluorocarbonos , Rim , Fígado , Ratos Sprague-Dawley , Testículo , Animais , Ácidos Alcanossulfônicos/toxicidade , Fluorocarbonos/toxicidade , Masculino , Ratos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Rim/efeitos dos fármacos , Rim/metabolismo , Testículo/efeitos dos fármacos , Testículo/metabolismo , Poluentes Ambientais/toxicidade , Esfingomielinas , Fosfatidilcolinas , Metabolismo dos Lipídeos/efeitos dos fármacos , Lipidômica , Pulmão/efeitos dos fármacos , Pulmão/metabolismo
4.
Nano Lett ; 23(19): 8842-8849, 2023 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-37729549

RESUMO

Wear of sliding contacts causes device failure and energy costs; however, the microscopic principle in activating wear of the interfaces under stress is still open. Here, the typical nanoscale wear, in the case of silicon against silicon dioxide, is investigated by single-asperity wear experiments and density functional theory calculations. The tests demonstrate that the wear rate of silicon in ambient air increases exponentially with stress and does not obey classical Archard's law. Series calculations of atomistic wear reactions generally reveal that the mechanical stress linearly drives the electron transfer to activate the sequential formation and rupture of interfacial bonds in the atomistic wear process. The atomistic wear model is thus resolved by combining the present stress-driven electron transfer model with Maxwell-Boltzmann statistics. This work may advance electronic insights into the law of nanoscale wear for understanding and controlling wear and manufacturing of material surfaces.

5.
World J Microbiol Biotechnol ; 40(7): 225, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38822208

RESUMO

Ganoderma lucidum is known for its bioactive compounds, such as polysaccharides and triterpenoids, which are crucial in food and medicine. However, liquid fermentation encounters challenges in terms of strain differentiation and stability. In this research, we employed atmospheric room temperature plasma mutation and a microbial microdroplet culture system to identify strains with enhanced biomass and triterpenoid production. The three mutant strains, YB05, YB09, and YB18, exhibited accelerated growth rates and antagonized the initial strain G0023 more effectively than the controls. Notably, YB18 displayed the fastest growth, with a 17.25% increase in colony radius. Shake flask cultivation demonstrated that, compared with the initial strain, YB05 and YB18 had 26.33% and 17.85% greater biomass, respectively. Moreover, the triterpenoid production of YB05 and YB18 surpassed that of the control by 32.10% and 15.72%, respectively, as confirmed by colorimetric detection. Importantly, these mutant strains remained stable for five generations. This study revealed a comprehensive screening system utilizing atmospheric pressure, room temperature plasma mutation technology and microbial droplet cultivation. This innovative approach offers a promising pathway for obtaining advantageous Ganoderma strains for liquid fermentation. The methodology of atmospheric room temperature plasma mutation and microbial microdroplet culture systems is detailed for better comprehension.


Assuntos
Fermentação , Mutação , Reishi , Triterpenos , Reishi/crescimento & desenvolvimento , Reishi/metabolismo , Reishi/genética , Triterpenos/metabolismo , Biomassa , Temperatura , Gases em Plasma/farmacologia
6.
Small ; 19(37): e2301515, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37162454

RESUMO

Two-dimensional (2D) lamellar materials are normally capable of rendering super-low friction, wear protection, and adhesion reduction in nanoscale due to their ultralow shear strength between two basal plane surfaces. However, high friction at step edges prevents the 2D materials from achieving super-low friction in macroscale applications and eventually leads to failure of lubrication performance. Here, taking graphene as an example, the authors report that not all step edges are detrimental. The armchair (AC) step edges are found to have only a minor topographic effect on friction, while the zigzag (ZZ) edges cause friction two orders of magnitude larger than the basal plane. The AC step edge is less reactive and thus more durable. However, the ZZ structure prevails when step edges are produced mechanically, for example, through mechanical exfoliation or grinding of graphite. The authors found a way to make the high-friction ZZ edge superlubricious by reconstructing the (6,6) hexagon structure to the (5,7) azulene-like structure through thermal annealing in an inert gas environment. This will facilitate the realization of graphene-based superlubricity over a wide range of industrial applications in which avoiding the involvement of step edges is difficult.

7.
Sensors (Basel) ; 23(2)2023 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-36679569

RESUMO

As an auxiliary means of remote sensing (RS) intelligent interpretation, remote sensing scene classification (RSSC) attracts considerable attention and its performance has been improved significantly by the popular deep convolutional neural networks (DCNNs). However, there are still several challenges that hinder the practical applications of RSSC, such as complex composition of land cover, scale-variation of objects, and redundant and noisy areas for scene classification. In order to mitigate the impact of these issues, we propose an adaptive discriminative regions learning network for RSSC, referred as ADRL-Net briefly, which locates discriminative regions effectively for boosting the performance of RSSC by utilizing a novel self-supervision mechanism. Our proposed ADRL-Net consists of three main modules, including a discriminative region generator, a region discriminator, and a region scorer. Specifically, the discriminative region generator first generates some candidate regions which could be informative for RSSC. Then, the region discriminator evaluates the regions generated by region generator and provides feedback for the generator to update the informative regions. Finally, the region scorer makes prediction scores for the whole image by using the discriminative regions. In such a manner, the three modules of ADRL-Net can cooperate with each other and focus on the most informative regions of an image and reduce the interference of redundant regions for final classification, which is robust to the complex scene composition, object scales, and irrelevant information. In order to validate the efficacy of the proposed network, we conduct experiments on four widely used benchmark datasets, and the experimental results demonstrate that ADRL-Net consistently outperforms other state-of-the-art RSSC methods.


Assuntos
Redes Neurais de Computação , Tecnologia de Sensoriamento Remoto , Tecnologia de Sensoriamento Remoto/métodos , Benchmarking , Inteligência
8.
BMC Nurs ; 22(1): 218, 2023 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-37357312

RESUMO

BACKGROUND: Neonatal nurses' working environments are highly stressful, and burnout is common. This study examines the effect of socioeconomic factors, perceived stress, and social support on neonatal nurse burnout. METHODS: A total of 311 neonatal nurses participated in this study. They were administered a validated Maslach Burnout Inventory. The study employed a 14-item perceived stress scale (PSS-14) and a social support rate scale (SSRS) to examine stress, socioeconomic factors, and lifestyles. RESULTS: Of the neonatal nurses, 40.19% had burnout, 89.60% had mild burnout, and 10.40% had moderate burnout; no neonatal nurse experienced severe burnout. Young nurses and those with low technical skills, poor interpersonal relationships, irregular diet, and insufficient rest were exposed to burnout (all p < 0.05).Most burnout nurses experienced moderate-severe perceived stress, and their PSS-14 scores were higher (all p < 0.05).The scores for objective social support, subjective social support, utilization of social support, total SSRS scores, and the level of social support were all lower in burnout nurses (all p < 0.05). Perceived stress was correlated positively and significantly with emotional exhaustion and personal accomplishment (all p < 0.05). Social support correlated significantly with and reduced personal accomplishments (p < 0.05). Age, poor interpersonal relationships, perceived stress, and social support were all independent factors associated with neonatal nurse burnout (all p < 0.05). CONCLUSION: The prevalence of burnout in neonatal nurses was higher than average. Socioeconomic factors, higher perceived stress, and lower social support contribute to neonatal nurse burnout. Nursing managers should pay attention to socioeconomic factors, perceived stress, and social support among neonatal nurses and employ strategies to reduce neonatal nurse burnout.

9.
World J Microbiol Biotechnol ; 39(6): 138, 2023 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-36991290

RESUMO

Ganoderma lucidum possesses a variety of valuable pharmacological activities, and it has long been used to prevent and treat various human diseases. Up to now, far too little attention has been paid to the liquid spawn of G. lucidum, and the development of the G. lucidum industry is constrained by them. This work aimed to study the key technologies and scale-up preparation of G. lucidum liquid spawn, to achieve large-scale preparation of liquid spawn and solve the problem of unstable quality of G. lucidum. The plate culture, primary shake flask culture, shake flask preparation, and fermentor preparation of G. lucidum liquid spawn were explored in the process of liquid fermentation. The results showed that plate broth volume significantly affected mycelial growth rate. Biomass in the primary shake flask culture is significantly influenced by the picking position of plate mycelium. An artificial neural network coupled with a genetic algorithm was used for carbon and nitrogen sources concentration optimization to increase biomass and substrate utilization. The optimized parameter combination is as follows: glucose, 14.5 g L-1; yeast extract powder, 8.5 g L-1. Under this condition, the biomass (9.82 g L-1) and biomass on reducing sugar (0.79 g g-1) increased by 18.03% and 27.41% compared to the control, respectively. The metabolic activity of liquid spawn prepared by different fermentation scales was diverse, and the liquid spawn prepared by the fermentor has better activity. Conceivably, the liquid spawn process can more conducive be applied to large-scale industrial production.


Assuntos
Reishi , Humanos , Reishi/metabolismo , Reatores Biológicos , Fermentação , Glucose/metabolismo , Micélio
10.
Reprod Biol Endocrinol ; 20(1): 124, 2022 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-35986323

RESUMO

BACKGROUND: Patients with recurrent implantation failure (RIF) may have more uterine contractions. Several observational studies suggested that atosiban administration around embryo transfer resulted in higher pregnancy rates in RIF patients. This study aimed to evaluate the effect of atosiban given before fresh embryo transfer on pregnancy outcomes of women with RIF. METHODS: A prospective, randomized, double-blind controlled clinical trial was performed in IVF center of Shanghai First Maternity and Infant Hospital. According to a computer-generated randomization list, 194 infertile women with RIF received fresh embryo transfer between July 2017 and December 2019 were randomly allocated into the atosiban (n = 97) and the placebo (n = 97) groups. Women in the treatment group received atosiban intravenously about 30 min before embryo transfer with a bolus dose of 6.75 mg over one minute. Those in the placebo group received only normal saline infusion for the same duration. RESULTS: There was no significant difference in the live birth rate between the atosiban and placebo groups (42.3% vs 35.1%, P = 0.302, RR = 1.206 (0.844-1.723)). No significant differences were found between the two groups in the positive pregnancy test, clinical pregnancy, ongoing pregnancy, miscarriage, multiple pregnancy, ectopic pregnancy and implantation rates. Similar results were found when stratified by the number of embryos previously transferred, number of previous failed embryo transfers, frequency of endometrial peristalsis on embryo transfer day (≥ 3 waves/min) or serum estradiol (E2) on the day of hCG above the median level. And, there was no correlation between the serum E2 level on the day of hCG and the frequency of endometrial peristalsis on embryo transfer day. The frequency of endometrial peristalsis on embryo transfer day, total FSH/HMG dosage and duration were the significant factors which independently predicted the likelihood of a live birth. CONCLUSIONS: These results suggested that atosiban treatment before fresh embryo transfer might not improve the live birth rate in RIF patients. TRIAL REGISTRATION: The study had been approved by the Institutional Review Board of the hospital (2017 ethics No.43) and was registered under Clinicaltrials.gov with an identifier NCT02893722.


Assuntos
Fertilização in vitro , Infertilidade Feminina , China , Implantação do Embrião , Feminino , Fertilização in vitro/métodos , Humanos , Infertilidade Feminina/terapia , Nascido Vivo , Gravidez , Taxa de Gravidez , Estudos Prospectivos , Vasotocina/análogos & derivados
11.
Inorg Chem ; 61(4): 1973-1981, 2022 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-35029373

RESUMO

A noncentrosymmetric salt-inclusion germanate, Rb10Li3Sc4Ge12O36F, was grown through spontaneous crystallization from a LiF-RbF flux. It crystallizes in the polar space group P31c with cell parameters of a = 10.7587(3) Å, c = 21.6691(10) Å, and Z = 2. Its structure features a complex 3D framework composed of helical [Ge4O12] chains from condensed [GeO4] tetrahedra running along the c axis, which are interconnected by the [ScO6] octahedra. Voids of the 3D net are filled with Rb+ ions, Li+ ions, and isolated trigonal-bipyramidal [Rb3Li2F] superalkali clusters. The title compound has a large band gap of 5.6 eV, a moderate powder second-harmonic-generation response of 0.9KDP, and an extremely small birefringence of 0.001, as was further unraveled by theoretical calculations.

12.
Phys Chem Chem Phys ; 23(2): 1392-1400, 2021 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-33476353

RESUMO

Metal-stabilized radicals have been increasingly exploited in modern organic synthesis. Here, we theoretically designed a metalloradical complex Co-C˙Ph3 with the triplet characters through the transition metal cobalt (Co0) coordinating a triphenylmethyl radical. The potential catalytic role of this novel metalloradical in the CO2 reduction with H2/CH4 in the gas phase was explored via density functional theory (DFT) calculations. For the CO2 reduction reaction with H2, there are two possible pathways: one (path A) is the activation of CO2 by Co-C˙Ph3, followed by the hydrogenation of CO2. The other (path B) starts from the splitting of the H-H bond by Co-C˙Ph3, leading to the transition-metal hydride complex CoH-H, which can reduce CO2. DFT computations show that path B is more favorable than path A as their rate-determining free energy barriers are 18.3 and 27.2 kcal mol-1, respectively. However, for the reduction of CO2 by CH4 two different products, CH3COOH and HCOOCH3, can be generated following different reaction routes. Both routes begin with one CH4 molecule approaching the metalloradical Co-C˙Ph3 to form the intermediate CoH-CH3. This intermediate can evolve following two different pathways, depending on whether the H bonded to Co is transferred to the O (pathway PO) or the C (pathway PC) of CO2. Comparing their rate-determining steps, we identified that the PO route is more favorable for the reduction of CO2 by CH4 to CH3COOH with the reaction barrier 24.5 kcal mol-1. Thus, the present Co0-based metalloradical system represents a viable catalytic protocol that can contribute to the effective utilization of small molecules (H2 and CH4) to reduce CO2, and provides an alternative strategy for the exploration of CO2 conversion.

13.
BMC Bioinformatics ; 21(1): 528, 2020 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-33203354

RESUMO

BACKGROUND: Next-generation sequencing technologies revolutionized genomics by producing high-throughput reads at low cost, and this progress has prompted the recent development of de novo assemblers. Multiple assembly methods based on de Bruijn graph have been shown to be efficient for Illumina reads. However, the sequencing errors generated by the sequencer complicate analysis of de novo assembly and influence the quality of downstream genomic researches. RESULTS: In this paper, we develop a de Bruijn assembler, called Clover (clustering-oriented de novo assembler), that utilizes a novel k-mer clustering approach from the overlap-layout-consensus concept to deal with the sequencing errors generated by the Illumina platform. We further evaluate Clover's performance against several de Bruijn graph assemblers (ABySS, SOAPdenovo, SPAdes and Velvet), overlap-layout-consensus assemblers (Bambus2, CABOG and MSR-CA) and string graph assembler (SGA) on three datasets (Staphylococcus aureus, Rhodobacter sphaeroides and human chromosome 14). The results show that Clover achieves a superior assembly quality in terms of corrected N50 and E-size while remaining a significantly competitive in run time except SOAPdenovo. In addition, Clover was involved in the sequencing projects of bacterial genomes Acinetobacter baumannii TYTH-1 and Morganella morganii KT. CONCLUSIONS: The marvel clustering-based approach of Clover that integrates the flexibility of the overlap-layout-consensus approach and the efficiency of the de Bruijn graph method has high potential on de novo assembly. Now, Clover is freely available as open source software from https://oz.nthu.edu.tw/~d9562563/src.html .


Assuntos
Algoritmos , Sequenciamento de Nucleotídeos em Larga Escala , Sequência de Bases , Cromossomos Humanos Par 14/genética , Análise por Conglomerados , Genoma Bacteriano , Genômica/métodos , Humanos , Software , Fatores de Tempo
14.
Bioinformatics ; 35(10): 1677-1685, 2019 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-30321266

RESUMO

MOTIVATION: High-throughput sequencing technology has revolutionized the study of metagenomics and cancer evolution. In a relatively simple environment, a metagenomics sequencing data is dominated by a few species. By analyzing the alignment of reads from microbial species, single nucleotide polymorphisms can be discovered and the evolutionary history of the populations can be reconstructed. The ever-increasing read length will allow more detailed analysis about the evolutionary history of microbial or tumor cell population. A simulator of shotgun sequences from such populations will be helpful in the development or evaluation of analysis algorithms. RESULTS: Here, we described an efficient algorithm, MetaSMC, which simulates reads from evolving microbial populations. Based on the coalescent theory, our simulator supports all evolutionary scenarios supported by other coalescent simulators. In addition, the simulator supports various substitution models, including Jukes-Cantor, HKY85 and generalized time-reversible models. The simulator also supports mutator phenotypes by allowing different mutation rates and substitution models in different subpopulations. Our algorithm ignores unnecessary chromosomal segments and thus is more efficient than standard coalescent when recombination is frequent. We showed that the process behind our algorithm is equivalent to Sequentially Markov Coalescent with an incomplete sample. The accuracy of our algorithm was evaluated by summary statistics and likelihood curves derived from Monte Carlo integration over large number of random genealogies. AVAILABILITY AND IMPLEMENTATION: MetaSMC is written in C. The source code is available at https://github.com/tarjxvf/metasmc. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.


Assuntos
Genética Populacional , Software , Algoritmos , Sequência de Bases , Sequenciamento de Nucleotídeos em Larga Escala , Metagenômica , Análise de Sequência de DNA
15.
Reprod Biol Endocrinol ; 18(1): 100, 2020 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-33046085

RESUMO

BACKGROUND: Trophoblast cells are required for the establishment of pregnancy and fetal development. Apoptosis is an essential feature for trophoblast invasion. Uncontrolled trophoblast apoptosis is related to some complicate pregnancies. Oxidative stress (OS) is an important inducer of trophoblast apoptosis. Cyclosporin A (CsA) has been shown to promote the activity of trophoblast cells and reduce OS-induced oxidative injury. We investigated the role and mechanism of CsA in oxidative stress-induced trophoblast cell apoptosis. METHODS: JEG-3 cells were cocultured with H2O2 and CsA. Cell viability and morphology were measured by MTT assay and DAPI staining. Cell apoptosis was tested with annexin V/PI staining. The expression of Bcl-2-associated X protein (Bax), B-cell lymphoma/leukemia-2 (Bcl-2), cleaved poly (ADP-ribose) polymerase (PARP) and pro-caspase-3 was assayed by western blotting. The protein expression and phosphorylation of p53 and mitogen-activated protein kinase (MAPK) kinases (JNK, ERK1/2 and p38) were examined by western blotting. RESULTS: CsA increased the viability, alleviated morphological injury and reduced cell apoptosis of the H2O2-treated JEG-3 cells. CsA also attenuated the activation of p53, decreased the expression of Bax and cleavage of PARP, and increased the expression of Bcl-2 and pro-caspase-3 in the JEG-3 treated with H2O2. Furthermore, CsA reduced the activation of JNK and P38 but had no significant effect on the activation of extracellular signal-regulated kinase 1/2 (ERK1/2) in the H2O2-treated JEG-3 cells. Promoting the activation of JNK and p38 impaired the protective effect of CsA on OS-induced trophoblast apoptosis. CONCLUSIONS: These results suggested that CsA protected trophoblast cells from OS-induced apoptosis via the inhibition of the p53 and JNK/p38 signaling pathways.


Assuntos
Apoptose/efeitos dos fármacos , Ciclosporina/farmacologia , Trofoblastos/efeitos dos fármacos , Linhagem Celular Tumoral , Citoproteção/efeitos dos fármacos , Feminino , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Fosforilação/efeitos dos fármacos , Gravidez , Substâncias Protetoras/farmacologia , Transdução de Sinais/efeitos dos fármacos , Trofoblastos/fisiologia , Proteína Supressora de Tumor p53/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
16.
Neurochem Res ; 45(12): 2915-2925, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33125618

RESUMO

Abnormally high expression of glial cell line-derived neurotrophic factor (GDNF) derived from glioma cells has essential impacts on gliomagenesis and development, but the molecular basis underlying increased GDNF expression in glioma cells remain unclear. This work aimed to study the molecular mechanisms that may explain the accumulation of GDNF in glioma. Firstly, we observed that cAMP response element-binding protein (CREB), known as an important transcription factor for binding of GDNF promoter region, was highly expressed with an apparent accumulation into the nucleus of glioma cells, which may contribute to the transcription of GDNF. Secondly, CUE domain-containing protein 2 (CUEDC2), a ubiquitin-regulated protein, could increase the amount of binding between the E3 ligase tripartite motif-containing 21 (TRIM21) and CREB and affect the CREB level. Like our previous study, it showed that there was a significantly down-regulation of CUEDC2 in glioma. Finally, our data suggest that GDNF expression is indirectly regulated by transcription factor ubiquitination. Indeed, down-regulation of CUEDC2, decreased the ubiquitination and degradation of CREB, which was associated to high levels of GDNF. Furthermore, abundant CREB involved in the binding to the GDNF promoter region contributes to GDNF high expression in glioma cells. Collectively, it was verified the GDNF expression was affected by CREB ubiquitination regulated by CUEDC2 level.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Fator Neurotrófico Derivado de Linhagem de Célula Glial/metabolismo , Glioma/metabolismo , Ubiquitinação/fisiologia , Linhagem Celular Tumoral , Regulação para Baixo , Regulação Neoplásica da Expressão Gênica/fisiologia , Glioma/genética , Humanos
17.
Artigo em Inglês | MEDLINE | ID: mdl-32863494

RESUMO

The ordinal dominance curve (ODC) is a useful graphical tool to compare two population distributions. These distributions are said to satisfy uniform stochastic ordering (USO) if the ODC for them is star-shaped. A goodness-of-fit test for USO was recently proposed when both distributions are unknown. This test involves calculating the L p distance between an empirical estimator of the ODC and its least star-shaped majorant. The least favorable configuration of the two distributions was established so that proper critical values could be determined; i.e., to control the probability of type I error for all star-shaped ODCs. However, the use of these critical values can lead to a conservative test and minimal power to detect certain non-star-shaped alternatives. Two new methods for determining data-dependent critical values are proposed. Simulation is used to show both methods can provide substantial increases in power while still controlling the size of the distance-based test. The methods are also applied to a data set involving premature infants. An R package that implements all tests is provided.

18.
Zhongguo Zhong Yao Za Zhi ; 45(8): 1901-1908, 2020 Apr.
Artigo em Zh | MEDLINE | ID: mdl-32489076

RESUMO

To study the correlation between toxicity and efficacy of different processed Aconiti Kusnezoffii Radix productsin industrial production, in order to define the optimal processing method for "attenuation-preservation effects". The HPLC method was used to determine the content of six aconitine alkaloids in Aconiti Kusnezoffii Radix and its different processed products. The Bliss method was used to determine the half-lethal dose(LD_(50)) or the maximum dose of Aconiti Kusnezoffii Radix and its different processed products in mice. The toluene-induced ear swelling method and the acetic acid twist method were used to investigate the anti-inflammatory and analgesic effects of different processed products. The results showed that: ① the total amount of diester alkaloids incrude Aconiti Kusnezoffii Radix was 0.358 8%; the total amount of diester alkaloids in Aconiti Kusnezoffii Radix prepared by pharmacopoeia-based boiling method was 0.002 2%, and the total amount of monoester alkaloids was 0.036 2%; the total amount of diester alkaloids in Aconiti Kusnezoffii Radix produced by atmospheric steaming method was 0.006 0%, and the total amount of monoester alkaloids was 0.056 7%; ② the LD_(50) of Aconiti Kusnezoffii Radix was 5.4 g·kg~(-1),and the maximum dose of processed products by two methods were 133.34 g·kg~(-1); pathological observation showed that compared with the normal group, the two kinds of processed products of Aconiti Kusnezoffii Radix had certain damage to the heart, liver and kidney; ③products processed by pharmacopoeia-based boiling method and atmospheric steaming method had anti-inflammatory and analgesic effects(P<0.01 or P<0.05). The anti-inflammatory and analgesic effects were as follows: the atmospheric steaming method was superior to the pharmacopoeia-based boiling method. The above results suggest that the crude Aconiti Kusnezoffii Radixis more toxic. The atmospheric steaming method can significantly reduce the toxicity, while retaining its good anti-inflammatory and analgesic effects, which is significantly better than the pharmacopoeia-based boiling method. The atmospheric steaming process is simple and easy to operate, and suitable for industrial production.


Assuntos
Aconitum , Alcaloides , Medicamentos de Ervas Chinesas , Aconitina/análise , Animais , Cromatografia Líquida de Alta Pressão , Camundongos
19.
Zhongguo Dang Dai Er Ke Za Zhi ; 22(4): 361-367, 2020 Apr.
Artigo em Zh | MEDLINE | ID: mdl-32312376

RESUMO

OBJECTIVE: To study the characteristics of vocalization during the still-face paradigm (SFP) before the age of 2 years and their correlation with the severity of autism spectrum disorder (ASD) symptoms at diagnosis in children with ASD. METHODS: A total of 43 children aged 7-23 months, who were suspected of ASD, were enrolled as the suspected ASD group, and 37 typical development (TD) children, aged 7-23 months, were enrolled as the TD group. The frequency and durations of vocalization in the SFP were measured. The children in the suspected ASD group were followed up to the age of 2 years, and 34 children were diagnosed with ASD. Autism Diagnostic Observation Schedule (ADOS) was used to assess the severity of symptoms. The correlation of the characteristics of vocalization before the age of 2 years with the severity of ASD symptoms was analyzed. RESULTS: Compared with the TD group, the ASD group had significant reductions in the frequency and durations of meaningful vocalization and vocalization towards people and a significant increase in the duration of vocalization toward objects (P<0.05). The Spearman correlation analysis showed that in the ASD group, the frequency and durations of total vocalization, non-speech vocalization, babbling, vocalization towards people, and vocalization towards objects were negatively correlated with the score of communication in ADOS (P<0.05). The frequency and durations of total vocalization, babbling, and vocalization towards people and the duration of vocalization towards objects were negatively correlated with the score of reciprocal social interaction in ADOS (P<0.05). The frequency of total vocalization, the duration of babbling, and the frequency and duration of vocalization towards people were negatively correlated with the score of play in ADOS (P<0.05). The frequency of total vocalization and non-speech vocalization and the frequency and durations of vocalization towards people were negatively correlated with the score of stereotyped behaviors and restricted interests in ADOS (P<0.05). The multiple linear regression analysis showed that the frequency of total vocalization was a negative predictive factor for the score of communication in ADOS (P<0.001), and the duration of vocalization towards people was a negative predictive factor for the score of reciprocal social interaction in ADOS (P<0.05). CONCLUSIONS: SFP can better highlight the abnormal vocalization of ASD children before the age of 2 years, and such abnormalities can predict the severity of ASD symptoms early.


Assuntos
Transtorno do Espectro Autista , Humanos , Lactente , Relações Interpessoais
20.
Zhongguo Zhong Yao Za Zhi ; 44(20): 4360-4365, 2019 Oct.
Artigo em Zh | MEDLINE | ID: mdl-31872620

RESUMO

Many clinical studies on Cheezheng Xiaotong Tiegao have been accumulated since it was launched in 1993,but they have not been comprehensively analyzed and evaluated. This study systematically retrieved relevant studies in six databases at home and abroad as of December 2017. This study analyzed the statistics of the included studies in several aspects,including publication time,region,fund,disease category and type of study. In this study,various tools were used to evaluate the methodological quality of included studies,such as the Cochrane collaboration's tool for assessing the risk of bias in randomized trials,MINORS,IHE,AMSTAR2.The results showed that the literatures were mainly published from 2010 to 2011,and a total of 28 projects were financially supported.The most involved disease was arthropathy. The randomized controlled trials were the majority in the included studies,but the quality was low,and most of the literatures didn't report the allocation concealment and blinding. This study comprehensively reflected the current situations and shortcomings of the clinical studies of Cheezheng Xiaotong Tiegao,and put forward several suggestions,in the expectation of providing a reference for the future clinical research direction of Cheezheng Xiaotong Tiegao.


Assuntos
Bibliometria , Medicamentos de Ervas Chinesas
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA