Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 53
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Pharm Biomed Anal ; 197: 113946, 2021 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-33611089

RESUMO

Cetrorelix, a potent third generation of luteinizing hormone releasing hormone (LHRH) antagonist, is a synthetic decapeptide used for treatment of infertility, prostatic hypertrophy and sexual hormone-dependent tumors. The approved drug of cetrorelix (Cetrotide, Asta Medica AG, Frankfurt, Germany.), was used for prevention of premature ovulation in patients undergoing a controlled ovarian stimulation (COS), followed by oocyte pick-up and assisted reproductive techniques, and has been shown safe and effective in controlled ovarian stimulation. Nevertheless, the study of aggregation products of cetrorelix was rarely reported. A simple liquid chromatography mass spectrometry (LC-MS/MS) method was developed for separation, identification and characterization of a new cetrorelix methylene dimer impurity in cetrorelix. The chromatographic separation was achieved on an XSelect Peptide CSH ™C18 column (150 × 4.6 mm, 3.5 µm particle size) using gradient elution with a mobile phase of ammonium formate buffer (pH 3.0, 20 mM), acetonitrile at a flow rate 1.0 mL min-1, and an ultraviolet detection wavelength of 226 nm. The new cetrorelix methylene dimer impurity was characterized by LC-MS/MS and it characteristic fragment ions were summarized. A simple, fast and accurate method was established for the determination of the molecular weight and structure of the new cetrorelix methylene dimer impurity. In this study, the results showed that the cetrorelix was highly unstable in formaldehyde conditions. In addition, it is proposed that the impact of formaldehyde in the environment on the quality of cetrorelix acetate for Injection should be evaluated during the production process.

3.
J Food Biochem ; 44(11): e13468, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32935351

RESUMO

This study aimed to evaluate the effect of oyster peptides and oyster powder on the procreative capacity of rats displaying reproductive dysfunction induced by cyclophosphamide (CTX). The amino acid composition and relative molecular mass of the oyster peptides and oyster powder were detected using an automatic amino acid analyzer and high-performance liquid chromatography (HPLC). After 5 d of exposure to CTX and six weeks of oyster peptide and oyster powder treatment, the biochemical serum indexes of the rats, the expression of related genes and proteins in the testes, as well as the antioxidant status and pathological state of the testes and kidneys were examined. The results showed that oyster peptides could effectively improve the biochemical blood indexes of rats, and increase the level of androgen in the blood, while improving the pathological state and oxidative stress state of the kidneys and testes, therefore, exhibiting a beneficial effect on reproductive injury. PRACTICAL APPLICATIONS: This study examined the activity of oyster peptides and their ability to enhance the procreative capacity of rats with reproductive dysfunction induced by CTX while analyzing the amino acid composition and relative molecular mass of the oyster peptides. The results of this experiment provided a preliminary theoretical basis for the development of new functional foods using oyster peptides.

4.
Food Funct ; 11(10): 8757-8767, 2020 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-32955075

RESUMO

This study assessed the melanogenesis effects of rice protein hydrolysate (RPH) and explored the underlying molecular mechanism of its characteristic peptides. In this investigation, human epidermal melanocyte (PIG1) cells were used to establish a UVB-induced model to evaluate the effect of RPH on melanin content, tyrosinase activity, and reactive oxygen species (ROS) levels. High performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was employed to identify the peptide composition (2-4 amino acids) in RPH. Enzymatic hydrolysis was employed to screen the characteristic peptides Leu-Leu-Lys (LLK), Leu-Pro-Lys (LPK), and pyroGlu-Lys (pEK), while their effect on the molecular mechanism involved in the melanin synthesis process was further explored using quantitative real-time polymerase chain reaction (PCR) and western blotting. The results indicated that RPH reduced the melanin content, tyrosinase activity, and ROS production in PIG1 cells. The selected peptides LLK, LPK, and pEK from RPH reduced the expression of tyrosinase-related protein 1 (TRP-1) and tyrosinase-related protein 2 (TRP-2) and affected melanin synthesis by regulating the JNK/ß-Trcp/NFκB-p65/MITF signaling pathway at the mRNA and protein levels. This study shows that RPH plays a vital role in the melanogenesis process, therefore, providing a theoretical basis for the use of RPH as a novel additive product.

5.
Environ Pollut ; 265(Pt A): 115091, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32806395

RESUMO

Lake eutrophication has become a serious environmental problem in China. Manipulations covering more elements of trophic pyramid are methods for lakes to obtain clear water state and should be studied in detail. In the present study, Meishan Dongpo Lake was divided into two parts, and a combined biomanipulation project was conducted in one part (RLake), and the other part was used as a control (CLake). Species of submerged-plant, fish, macrobenthos, and zooplankton were screened and a certain number of them were added to adjust the eco-chain in RLake. After restoration, the coverage of submerged macrophytes reached >85%; zooplankton greater than 0.6 mm in size increased in number, and the ratio of zooplankton biomass to chlorophyll-a (Chl-a) concentration increased. The dominant fish species changed, and disturbance of the sediment was reduced. The average density of mollusks in RLake was 111.5 ± 19.8 ind m-2, which was much higher than that in CLake (36.7 ± 2.1 ind m-2). Water quality and clarity were substantially improved, and nutrient concentrations, particularly total phosphorus, total nitrogen, and Chl-a were significantly reduced. The aquatic community parameters were negatively correlated with the nutrient parameters and Chl-a. The ecological restoration have adjusted the aquatic ecosystem in RLake, and many positive feedback effects among the aquatic communities made them remove internal nutrients and Chl-a more efficiently.


Assuntos
Lagos , Qualidade da Água , Animais , China , Ecossistema , Eutrofização
6.
Cancer Manag Res ; 12: 2789-2802, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32425596

RESUMO

Background: Hypoxia-induced chemoresistance is recognized as a major obstacle to the successful treatment of gastric cancer (GC). Circular RNAs (circRNAs) have been proposed to implicate in resistance to chemotherapeutic drugs. However, whether circNRIP1 is involved in the development of hypoxia-induced 5-fluorouracil (5-FU) resistance remains largely unknown. Methods: Gene expression was evaluated using quantitative real-time polymerase chain reaction and Western blot. The impact of circNRIP1 on hypoxia-induced resistance to 5-FU was investigated by determining glucose consumption, lactate production and glucose-6-phosphate (G6P) levels. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolim bromide assay was performed to assess cell survival. Results: circNRIP1 was upregulated in GC cells. Hypoxia induced the upregulation of circNRIP1 and reduced the sensitivity of GC cells to 5-FU, as evidenced by the increase in multidrug resistance 1 gene, P-glycoprotein, hypoxia-inducible factor-1α (HIF-1α) and G6P levels, glucose consumption, lactate production, as well as cell survival. Silencing of circNRIP1 enhanced the sensitivity of GC cells to 5-FU under a hypoxic condition. microRNA (miR)-138-5p was confirmed as a downstream target gene of circNRIP1, and upregulation of miR-138-5p could reverse the effect of circNRIP1 on hypoxia-induced 5-FU resistance. Additionally, HIF-1α was a target gene of miR-138-5p. More significantly, the effect of circNRIP1 on hypoxia-induced 5-FU resistance was markedly blocked by 2-DG treatment. Conclusion: circNRIP1 functioned as a miR-138-5p sponge to enhance hypoxia-induced resistance to 5-FU through modulation of HIF-1α-dependent glycolysis, which provides a novel potential approach to overcome hypoxia-induced 5-FU resistance in GC.

7.
Materials (Basel) ; 13(7)2020 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-32235340

RESUMO

This Special Issue "Sustainable Designed Pavement Materials" has been proposed and organized as a means to present recent developments in the field of environmentally-friendly designed pavement materials. For this reason, articles included in this special issue relate to different aspects of pavement materials, from industry solid waste recycling to pavement materials recycling, from pavement materials modification to asphalt performance characterization, from pavement defect detection to pavement maintenance, and from asphalt pavement to cement concrete pavement, as highlighted in this editorial.

8.
Chem Rev ; 120(5): 2879-2949, 2020 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-32078296

RESUMO

Heterogeneous interfaces that are ubiquitous in optoelectronic devices play a key role in the device performance and have led to the prosperity of today's microelectronics. Interface engineering provides an effective and promising approach to enhancing the device performance of organic field-effect transistors (OFETs) and even developing new functions. In fact, researchers from different disciplines have devoted considerable attention to this concept, which has started to evolve from simple improvement of the device performance to sophisticated construction of novel functionalities, indicating great potential for further applications in broad areas ranging from integrated circuits and energy conversion to catalysis and chemical/biological sensors. In this review article, we provide a timely and comprehensive overview of current efficient approaches developed for building various delicate functional interfaces in OFETs, including interfaces within the semiconductor layers, semiconductor/electrode interfaces, semiconductor/dielectric interfaces, and semiconductor/environment interfaces. We also highlight the major contributions and new concepts of integrating molecular functionalities into electrical circuits, which have been neglected in most previous reviews. This review will provide a fundamental understanding of the interplay between the molecular structure, assembly, and emergent functions at the molecular level and consequently offer novel insights into designing a new generation of multifunctional integrated circuits and sensors toward practical applications.

9.
Langmuir ; 36(6): 1462-1466, 2020 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-31986886

RESUMO

Trace explosives can be detected with the help of a portable device using a flexible active self-assembled monolayer (SAM). 9,10-diphenyl anthracene with aggregation-induced emission enhancement (AIEE) properties is selected as the fluorophore. Phosphoric acid as the anchor group is linked to the fluorophore through an alkyl chain and able to self-assemble into a dense monolayer on the HfO2 adhesion layer on a flexible substrate. The dense SAMs show high fluorescence intensity, which can be quenched by nitroaromatic compounds (NACs), and have advantages of high response rate, sensitivity, reversibility, and selectivity.

10.
Chemphyschem ; 21(2): 181-186, 2020 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-31769199

RESUMO

Organic semiconductor (OSC) crystals have great potential to be applied in many fields, as they can be flexibly designed according to the demands and show an outstanding device performance. However, OSCs with the capacity of solid-state crystallization (SSC) are developing too slowly to meet demands in productions and applications, due to their difficulties in molecular design and synthesis, unclear mechanism and high dependence on experimental conditions. In this work, in order to solve the problems, we synthesized an organic semiconductor capable of SSC at room temperature by adjusting the relationship between conjugated groups and functional groups. The thermodynamic and kinetic properties have been studied to discover the model of film SSC. Moreover, it can be purposefully controlled to prepare the high-quality crystals, and their corresponding organic electronic devices were further fabricated and discussed.

11.
Viruses ; 11(11)2019 11 08.
Artigo em Inglês | MEDLINE | ID: mdl-31717393

RESUMO

The prevalence and variation of the H9N2 avian influenza virus (AIV) pose a threat to public health. A total of eight viruses isolated from farmed poultry in South China during 2017-2018 were selected as representative strains for further systematic study. Phylogenetic analyses indicated that these prevalent viruses belong to the Y280-like lineage and that the internal genes are highly similar to those of recently circulating human H7N9 viruses. The receptor-binding assay showed that most of the H9N2 isolates preferentially bound to the human-like receptor, increasing the risk of them crossing the species barrier and causing human infection. Our in vitro, multi-step growth curve results indicate these viruses can effectively replicate in mammalian cells. Infection in mice showed that three viruses effectively replicated in the lung of mice. Infection in swine revealed that the viruses readily replicated in the upper respiratory tract of pig and effectively induced viral shedding. Our findings suggested that the H9N2 AIVs circulating in poultry recently acquired an enhanced ability to transmit from avian to mammalians, including humans. Based on our findings, we propose that it is essential to strengthen the efforts to surveil and test the pathogenicity of H9N2 AIVs.


Assuntos
Vírus da Influenza A Subtipo H9N2 , Influenza Aviária/transmissão , Influenza Humana/transmissão , Infecções por Orthomyxoviridae/transmissão , Animais , Aves , China/epidemiologia , Genes Virais , Humanos , Subtipo H7N9 do Vírus da Influenza A/genética , Vírus da Influenza A Subtipo H9N2/genética , Vírus da Influenza A Subtipo H9N2/patogenicidade , Camundongos , Infecções por Orthomyxoviridae/veterinária , Filogenia , Aves Domésticas/virologia , Receptores Virais/genética , Suínos , Replicação Viral
12.
Materials (Basel) ; 12(22)2019 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-31744241

RESUMO

High-viscosity modified asphalt is mainly used as a binder for porous asphalt in China and Japan. In order to meet the demand for using porous asphalt under high temperature condition in Africa, high-viscosity asphalt made from low-grade matrix asphalt, which is commonly used in Africa is investigated. Based on simulation of local climate in Africa, the suitable range of high viscosity additive content for different matrix asphalt was obtained by analyzing dynamic viscosity of the asphalt. Through PG high temperature grading, multi-stress repeated creep, accelerated fatigue, temperature sweep and other tests, changes of high temperature, anti-fatigue and anti-shear indicators before and after modification were compared and analyzed and effects of different matrix asphalt were also studied. Finally, considering engineering requirements, mixing and compaction temperatures of various high-viscosity modified asphalt were determined through study of viscosity-temperature characteristics. This research provides a support for preparation of high-viscosity modified asphalt and porous asphalt mixture by using low grade asphalt. The research achievements can help to guide the material design and application of porous asphalt in Africa and other high temperature areas.

13.
Nat Commun ; 10(1): 3872, 2019 08 27.
Artigo em Inglês | MEDLINE | ID: mdl-31455804

RESUMO

Molecular self-assembly into crystallised films or wires on surfaces produces a big family of motifs exhibiting unique optoelectronic properties. However, little attention has been paid to the fundamental mechanism of molecular crystallisation. Here we report a biomimetic design of phosphonate engineered, amphiphilic organic semiconductors capable of self-assembly, which enables us to use real-time in-situ scanning probe microscopy to monitor the growth trajectories of such organic semiconducting films as they nucleate and crystallise from amorphous solid states. The single-crystal film grows through an evolutionary selection approach in a two-dimensional geometry, with five distinct steps: droplet flattening, film coalescence, spinodal decomposition, Ostwald ripening, and self-reorganised layer growth. These sophisticated processes afford ultralong high-density microwire arrays with high mobilities, thus promoting deep understanding of the mechanism as well as offering important insights into the design and development of functional high-performance organic optoelectronic materials and devices through molecular and crystal engineering.

14.
Spectrochim Acta A Mol Biomol Spectrosc ; 219: 427-435, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31063957

RESUMO

Whole blood viscosity (WBV) is a group of important clinical indicators of cardio-cerebral vascular diseases. Existing detection methods for WBV are complex, making them inconvenient for large population screening. Blood viscosity is closely related to the deformability and aggregation of erythrocytes, which are associated with haemoglobin. Haemoglobin has obvious near-infrared (NIR) spectral absorption. Scattering occurs when NIR light enters a viscous blood sample, and its scattering degree is correlated with blood viscosity. Based on repeated spectral measurements and spectral similarity, spectral noise-to-signal ratio (NSR) was proposed to quantify the spectral scattering effect in the blood sample. A novel selection method of piecewise-continuous wavelengths, named NSR priority-partial least squares (NSRP-PLS), was proposed and applied for visible-NIR quantitative analysis of WBV with high, medium and low shear rates [WBV(H), WBV(M), WBV(L)]. Modelling was separately performed by gender to allow for systematic gender differences in blood viscosity. For the NIR-predicted and clinically measured values of the three WBV indicators in independent validation, the root mean square errors for prediction (SEP) were 0.498, 0.222 and 0.193 (mPa·s), respectively. And the correlation coefficients (RP) were 0.927, 0.934 and 0.927, respectively. Compared with the three current well-performing methods (MW-PLS, CARS-PLS and SPA-PLS), the proposed NSRP-PLS method achieved better predictive accuracy. Results indicated that visible-NIR spectroscopy combined with the NSRP-PLS method can be used for the quantitative analysis of WBV. The proposed analytical method is rapid, reagent-free and is scientific and meaningful for cardio-cerebral vascular diseases screening in large populations.


Assuntos
Viscosidade Sanguínea , Algoritmos , Feminino , Humanos , Análise dos Mínimos Quadrados , Masculino , Razão Sinal-Ruído , Espectroscopia de Luz Próxima ao Infravermelho/métodos
15.
Spectrochim Acta A Mol Biomol Spectrosc ; 219: 179-185, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31035128

RESUMO

The rapid and non-destructive discriminant analysis of rice seeds has great significance for large-scale agriculture. Using near-infrared (NIR) diffuse-reflectance spectroscopy with partial least squares-discriminant analysis (PLS-DA), a variety identification method of multi-grain rice seeds was developed. The equidistant combination method was adopted for large-range wavelength screening. A step-by-step phase-out method was proposed to eliminate interference wavelengths and improve the predicted effect. The optimal wavelength model was a combination of 54 wavelengths within 808-974 nm of the short-NIR region. One type of pure rice variety (Y Liangyou 900) was used for identification (negative). Positive samples included the other four pure varieties and contamination of Y Liangyou 900 by the above four varieties. The recognition-accuracy rates for positive, negative and total validation samples reached 93.1%, 95.1%, and 94.3%, respectively. In the long-NIR region, the local optimal wavelength model was a combination of 49 wavelengths within 1188-1650 nm, and the recognition-accuracy rates for positive, negative and total validation samples were 90.3%, 94.1%, and 92.5%, respectively. Results confirmed the feasibility of NIR spectroscopy for variety identification of multi-grain rice seeds. The proposed two discrete-wavelength models located in the short- and long-NIR regions can provide valuable reference to a dedicated spectrometer.


Assuntos
Oryza/química , Sementes/química , Análise Discriminante , Grão Comestível/química , Análise dos Mínimos Quadrados , Espectroscopia de Luz Próxima ao Infravermelho/economia , Espectroscopia de Luz Próxima ao Infravermelho/métodos
16.
Pharmacol Res ; 142: 294-302, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30553824

RESUMO

Stress response refers to the systemic nonspecific response upon exposure to strong stimulation or chronic stress, such as severe trauma, shock, infection, burn, major surgery or improper environment, which disturb organisms and damage their physical and psychological health. However, the pathogenesis of stress induced disorder remains complicated and diverse under different stress exposure. Recently, studies have revealed a specific role of microRNAs (miRNAs) in regulating cellular function under different types of stress, suggesting a significant role in the treatment and prevention of stress-related diseases, such as stress ulcer, posttraumatic stress disorder, stress-induced cardiomyopathy and so on. This paper have reviewed the literature on microRNA related stress diseases in different databases including PubMed, Web of Science, and the MiRbase. It considers only peer-reviewed papers published in English between 2004 and 2018. This review summarizes new advances in principles and mechanisms of miRNAs regulating stress signalling pathway and the role of miRNAs in human stress diseases. This comprehensive review is to provide an integrated account of how different stresses affect miRNAs and how stress-miRNA pathways may, in turn, be linked with disease, which offers some potential strategies for stress disorder treatment. Furthermore, the limitation of current studies and challenges for clinical use are discussed.


Assuntos
MicroRNAs/fisiologia , Estresse Fisiológico/genética , Animais , Humanos , MicroRNAs/biossíntese
17.
Org Lett ; 20(20): 6490-6493, 2018 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-30284837

RESUMO

A direct C(sp2)-H thiolation of aromatic amides with disulfides was developed. The coupling reaction proceeds between the thioether radical and cobaltacycle intermediate. This method exhibits a relatively broad substrate scope and high functional group compatibility. A mechanistic study indicates that the cobalt(IV) intermediate is probably formed during the course of the reaction. The thiolation product can be transformed to Quetiapine, which is an atypical antipsychotic agent approved for the treatment of schizophrenia and bipolar disorder.

18.
Angew Chem Int Ed Engl ; 57(43): 14026-14031, 2018 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-30215882

RESUMO

Achieving gate control with atomic precision, which is crucial to the transistor performance on the smallest scale, remains a challenge. Herein we report a new class of aromatic-ring molecular nanotransistors based on graphene-molecule-graphene single-molecule junctions by using an ionic-liquid gate. Experimental phenomena and theoretical calculations confirm that this ionic-liquid gate can effectively modulate the alignment between molecular frontier orbitals and the Fermi energy level of graphene electrodes, thus tuning the charge-transport properties of the junctions. In addition, with a small gate voltage (|VG |≤1.5 V) ambipolar charge transport in electrochemically inactive molecular systems (EG >3.5 eV) is realized. These results offer a useful way to build high-performance single-molecule transistors, thus promoting the prospects for molecularly engineered electronic devices.

19.
Materials (Basel) ; 11(8)2018 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-30087291

RESUMO

This study investigated the effect of seven healing agents on crack healing ability of long-term aged asphalt and its mortar. Different healing agents including sunflower oil, aromatic oil, bitumen emulsion, and maltene-based emulsions were used. The crack healing of asphalt made use of two asphalt disk samples and healing was evaluated using direct tensile tests. For asphalt mortar, notched semi-circular samples were used. Test results indicated that the crack healing of asphalt and its mortar depended strongly on the type of healing agent. In general, asphalt healed faster than its mortar. Asphalt healing could be well improved by using oil agents, while asphalt mortar could be well healed with maltene-based emulsions. The crack healing of asphalt mortar developed rapidly followed by a steady state of increase. Initial crack healing using healing agents could be contributed by the diffusion and softening effects, which resulted in low strength recovery. Long term healing could lead to the bonding reconstitution in the cracks, which were decisive for the final strength gain. The promising healing agent should be able to achieve maximum strength recovery to resist cracking as well as a sufficient re-healing ability to deal with crack opening and closing.

20.
J Vet Res ; 62(1): 7-15, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29978122

RESUMO

Introduction: Classical swine fever (CSF) has caused severe economic losses in pig production in many countries. Recent CSF outbreaks in China are mainly associated with sub-genotype 2.1 of CSF virus (CSFV). Although there is abundant information regarding 2.1 isolates, few data are available on whole-genome analysis. Material and Methods: The biological and genome characteristics of three recently emerged Chinese CSFV isolates, i.e. SD2014-1, SD2014-2, and SD2014-3, were fully analysed. Results: Sequence analysis showed that the isolates shared 83.4%-95.0% nucleotide identity with eight other CSFV isolates. In addition, the 5' untranslated region (5'UTR) and the non-structural (NS) proteins NS3, NS4A, and NS4B were more conserved than other regions of the genome. Phylogenetic analysis based on the complete genome sequences or full-length structural protein E2 gene sequences revealed that the three isolates belonged to sub-genotype 2.1b. In addition, several unique molecular characteristics of the 5'UTR, 3'UTR, and E2 were identified. Conclusion: The genomic variations of the three isolates will support further analysis of virulence determinants and the evolutionary trend of CSFV.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA