Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 86
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Eur J Neurosci ; 2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38711280

RESUMO

Gastrodin, an anti-inflammatory herbal agent, is known to suppress microglia activation. Here, we investigated whether it would exert a similar effect in reactive astrocytes and whether it might act through the renin-angiotensin system (RAS) and sirtuin 3 (SIRT3). Angiotensinogen (ATO), angiotensin-converting enzyme (ACE), angiotensin II type 1 (AT1) and type 2 (AT2) receptor and SIRT3 expression was detected in TNC-1 astrocytes treated with BV-2 microglia conditioned medium (CM) with or without gastrodin and lipopolysaccharide (LPS) pre-treatment by RT-PCR, immunofluorescence and western blotting analysis. Expression of C3 (A1 astrocyte marker), S100A10 (A2 astrocyte marker), proinflammatory cytokines and neurotrophic factors was then evaluated. The results showed a significant increase of ATO, ACE, AT1, SIRT3, C3, proinflammatory cytokines and neurotrophic factors expression in TNC-1 astrocytes incubated in CM + LPS when compared with cells incubated in the CM, but AT2 and S100A10 expression was reduced. TNC-1 astrocytes responded vigorously to BV-2 CM treated with gastrodin + LPS as compared with the control. This was evident by the decreased expression of the abovementioned protein markers, except for AT2 and S100A10. Interestingly, SIRT3, IGF-1 and BDNF expression was enhanced, suggesting that gastrodin inhibited the expression of RAS and proinflammatory mediators but promoted the expression of neurotrophic factors. And gastrodin regulated the phenotypic changes of astrocytes through AT1. Additionally, azilsartan (a specific inhibitor of AT1) inhibited the expression of C3 and S100A10, which remained unaffected in gastrodin and azilsartan combination treatment. These findings provide evidence that gastrodin may have a therapeutic effect via regulating RAS-SIRT3.

2.
Langmuir ; 40(6): 3222-3230, 2024 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-38287218

RESUMO

UiO-66-type metal-organic frameworks have been considered as promising adsorbents for capturing Ag(I) from wastewater. However, uncertainties persist regarding the specific absorptivity of individual functional groups to the UiO-66 framework structure. In this study, UiO-66-type metal-organic frameworks (UiO-66-X), featuring diverse functional groups (X = -(OH)2, -(COOH)2, -NO2, -NH2, -SO3H, -(SH)2), were synthesized in situ for Ag(I) capture. The findings revealed that functionalization significantly enhanced the adsorption capacity of Ag(I). Notably, quantitative analysis showed that 1 mol of -SH functional group onto the UiO-66 framework structure can adsorb 0.73 mol of Ag(I) ions, surpassing those of -COOH, -OH, -NH2, -SO3H, and -NO2 by 2.4-, 3.5-, 3.8-, 9.1-, and 24.3-fold, respectively. This represents the first assessment of the adsorption capacity of functionalized UiO-66 for Ag(I) based on each effective functional group, addressing limitations in traditional unit mass calculations. Further, the adsorption mechanism of UiO-66-X for selectively capturing Ag(I) was elucidated through experimental and theoretical analyses. Additionally, selectivity and practical applications confirm that UiO-66-(SH)2 exhibits strong anti-interference ability, whether in natural water bodies with complex compositions or in industrial wastewater under harsh conditions. We anticipate that this study will enhance our understanding of structure-performance dependencies of multivariate MOFs for designing novel adsorbents for Ag(I) capture.

3.
Environ Res ; 251(Pt 2): 118671, 2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38479719

RESUMO

The low cost and high efficiency of microwave-assisted regeneration render it a viable alternative to conventional regeneration methods. To enhance the regeneration performance, we developed a coupled electromagnetic, heat, and mass transfer model to investigate the heat and mass transfer mechanisms of activated carbon during microwave-assisted regeneration. Simulation results demonstrated that the toluene desorption process is governed by temperature distribution. Changing the input power and flow rate can promote the intensity of hot spots and adjust their distribution, respectively, thereby accelerating toluene desorption, inhibiting readsorption, and promoting regeneration efficiency. Ultimately, controlling the input power and flow rate can flexibly adjust toluene emissions to satisfy the processing demands of desorbed toluene. Taken together, this study provides a comprehensive understanding of the heat and mass transfer mechanisms of microwave-assisted regeneration and insights into adsorbent regeneration.


Assuntos
Carvão Vegetal , Temperatura Alta , Micro-Ondas , Tolueno , Tolueno/química , Adsorção , Carvão Vegetal/química , Modelos Químicos
4.
Opt Express ; 31(18): 28939-28945, 2023 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-37710702

RESUMO

We study the momentum-space evolutions for chiral optical responses of multi-mode resonators scattering plane waves of varying incident directions. It was revealed, in our previous study [Phys. Rev. Lett.126, 253901 (2021)10.1103/PhysRevLett.126.253901], that for single-mode resonators the scattering optical chiralities characterized by circular dichroism (CD) are solely decided by the third Stokes parameter distributions of the quasi-normal mode (QNM) radiations: CD = S3. Here we extend the investigations to multi-mode resonators, and explore numerically the dependence of optical chiralities on incident directions from the perspectives of QNM radiations and their circular polarization singularities. In contrast to the single-mode regime, for multi-mode resonators it is discovered that CDs defined in terms of extinction, scattering and absorption generally are different and cannot reach the ideal values of ±1 throughout the momentum sphere. Though the exact correspondence between CD and S3 does not hold anymore in the multi-mode regime, we demonstrate that the positions of the polarization singularities still serve as an efficient guide for identifying those incident directions where the optical chiralities can be extremized.

5.
J Cell Mol Med ; 25(5): 2377-2389, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33496386

RESUMO

The exact molecular mechanism underlying erythroblast enucleation has been a fundamental biological question for decades. In this study, we found that miR-144/451 critically regulated erythroid differentiation and enucleation. We further identified CAP1, a G-actin-binding protein, as a direct target of miR-144/451 in these processes. During terminal erythropoiesis, CAP1 expression declines along with gradually increased miR-144/451 levels. Enforced CAP1 up-regulation inhibits the formation of contractile actin rings in erythroblasts and prevents their terminal differentiation and enucleation. Our findings reveal a negative regulatory role of CAP1 in miR-144/451-mediated erythropoiesis and thus shed light on how microRNAs fine-tune terminal erythroid development through regulating actin dynamics.


Assuntos
Diferenciação Celular/genética , Células Precursoras Eritroides/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , MicroRNAs/genética , Interferência de RNA , Serina Endopeptidases/genética , Regiões 3' não Traduzidas , Animais , Biomarcadores , Linhagem Celular , Células Cultivadas , Células Precursoras Eritroides/citologia , Eritropoese/genética , Imunofenotipagem , Camundongos
6.
Opt Lett ; 46(8): 1934-1937, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33857109

RESUMO

In the quasi-periodic structure (QPS) containing InSb, a nonreciprocal absorber with a narrow band of angular polarization sensitive regions is studied. Due to the effective role of the antireflection layers (ALs), the effective impedance of the overall structure matches the vacuum wave impedance. Benefiting from the special absorption structure, an absorption band will be created in the photonic bandgap. The results of the investigation show that, with the same parameters, the QPS has a larger frequency bandwidth than the periodic structure and, if the incident frequency of the electromagnetic wave is the same, the former has a larger angular selective range. The degrees of polarization separation and nonreciprocal ability of the presented QPS can be regulated by temperature and magnetic induction intensity. Consequently, the proposed QPS can provide a new basis for the development of polarization separators and nonreciprocal devices.

7.
Liver Int ; 41(3): 562-573, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33205544

RESUMO

BACKGROUND & AIMS: Liver transplantation (LTx) is one of the most effective treatments for hepatocellular carcinoma (HCC); however, tumour recurrence after LTx often leads to poor outcomes. This study investigated the value of circulating tumour cells (CTCs) as a predictor of recurrence following LTx in patients with HCC. METHODS: This analysis included 193 patients with HCC who underwent LTx at our institute and accepted pre- and post-operative CTC detection; 38 were selected for serial CTC monitoring. The predictive value of CTCs for tumour recurrence in patients with HCC following LTx was evaluated. Single-cell whole genome sequencing was used to characterize CTCs. RESULTS: Overall, the CTC burden decreased after LTx (P < .05). Post-operative CTC count ≥ 1 per 5 mL peripheral blood was identified as a potential biomarker for predicting tumour recurrence after LTx, especially in patients with no detectable CTCs prior to LTx and negative tumour serological biomarkers. The predictive value of post-operative CTC count ≥ 1 per 5 mL blood was retained in patients who did not meet the Milan criteria, University of California San Francisco (UCSF) criteria, or Fudan criteria (all P < .05). Furthermore, post-operative serial CTC detection may be useful in post-surgical surveillance for HCC recurrence. CONCLUSIONS: CTCs may be a useful biomarker to evaluate recurrence risk following LTx in patients with HCC. Evaluation based on CTC detection may enhance the post-transplant management of HCC, and improve the therapeutic efficacy of LTx.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Transplante de Fígado , Células Neoplásicas Circulantes , Carcinoma Hepatocelular/cirurgia , Humanos , Neoplasias Hepáticas/cirurgia , Recidiva Local de Neoplasia , São Francisco
8.
Anal Bioanal Chem ; 413(16): 4353-4362, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34013401

RESUMO

A novel electrochemical DNA sensor was designed to detect Helicobacter pylori based on accordion-like Ti3C2Tx. Here the multilayer Ti3C2Tx obtained by DMSO delamination was used to modify the glass carbon electrode, with a large specific surface area and excellent conductivity. Au nanoparticles were supported on the modified electrode and worked as an effective carrier to fix the capture probe (cpDNA) with sulfhydryl group through the firm binding of Au-S bond. Such an accordion-like Ti3C2Tx structure provides an ultrahigh electroactive surface area and ample binding sites for accommodating Au nanoparticles, which is advantageous for the signal amplification during the detection. And further, the sandwich structure formed by hybridizing cpDNA with target DNA sequence (tDNA) and rpDNA (rpDNA is a strand of DNA that can be base-paired with the tested tDNA) increases greatly the current signal and enhances the sensitivity of the electrochemical DNA sensor. Under optimal conditions, the developed electrochemical DNA sensor showed a wide linear range from 10-11 to 10-14 M and a low detection limit of 1.6 × 10-16 M and exhibited good sensitivity, reproducibility, and stability. A novel electrochemical DNA sensor with simple sandwich structure was designed to detect H. pylori based on accordion-like Ti3C2Tx.


Assuntos
DNA Bacteriano/análise , Técnicas Eletroquímicas/métodos , Helicobacter pylori/isolamento & purificação , Nanopartículas Metálicas/química , Titânio/química , Animais , Técnicas Biossensoriais , Eletrodos , Ouro/química , Infecções por Helicobacter/sangue , Infecções por Helicobacter/microbiologia , Humanos , Limite de Detecção , Leite/microbiologia , Hibridização de Ácido Nucleico/métodos
9.
Anal Bioanal Chem ; 413(16): 4267-4275, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34013399

RESUMO

In our investigation, a smartphone-integrated ratiometric fluorescent sensing system with lanthanide-based infinite coordination polymers (Ce-GMP-DPA@Tb-DPA) as signal probe has been successfully constructed for sensitive and portable detection of water in organic solvents. The Ce-GMP-DPA presents blue luminescence which is suppressed once the Tb-DPA is integrated to form the complex of Ce-GMP-DPA@Tb-DPA. Due to the energy transfer from Ce to Tb, the as-formed Ce-GMP-DPA@Tb-DPA exhibits green fluorescence of Tb-DPA. The presence of water can decompose the Tb-DPA, which blocks energy transfer from Ce to Tb, resulting in the decrease of green emission of Tb-DPA and the recovery of blue emission of Ce-GMP-DPA. Therefore, a ratiometric fluorescence assay is established for quantitative water detection within a wide linear range from 0.2 to 90.0% in ethanol. The limit of detection (LOD) reaches as low as 0.16% in ethanol, 0.62% in THF, and 0.0076% in acetonitrile, respectively. Furthermore, a smartphone installed with Color Picker APP as signal reader and analyzer is designed to integrate with the detection assay. With white spirit as real sample, water can be on-site detected with high accuracy (RSD < 2.81%). The developed platform presents great potential for portable water detection in practical application with merits of low cost, easy carry, and simple operation.

10.
J Opt Soc Am A Opt Image Sci Vis ; 38(6): 897-907, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-34143159

RESUMO

In this paper, the equations for the transfer matrix method of one-dimensional cylindrical magnetized plasma photonic crystals are proposed, and its nonreciprocal properties based on the Thue-Morse sequence are also studied. By adding the influence of the magnetic field into Maxwell's equations in the cylindrical coordinate system, the transmission matrix equation of cylindrical wave propagation in the cylindrical medium is obtained and a quasi-periodic structure with the Thue-Morse sequence is designed to study its nonreciprocal features. By considering Maxwell's equations and the equations of motion of charged particles, the relative dielectric function of plasma under the $z$-axis magnetic field is achieved. Considering the influences of this dielectric function in the cylindrical coordinate system, the transmission matrix equations of cylindrical wave propagation in the cylindrical medium are derived, and those equations are used to design a cylindrical structure with two layers of ordinary medium and one layer of plasma satisfying the Thue-Morse sequence. It is concluded that the nonreciprocal phenomenon becomes more and more obvious with the increase of the plasma frequency, the relative dielectric constant of the medium, and the incident angle. But with the increase of ${\omega _c}$, the nonreciprocal propagation is attenuated, and there is no significant change when the collision frequency is enlarging.

11.
Appl Opt ; 60(7): 1834-1842, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33690271

RESUMO

The phenomenon of non-reciprocity in the spin Hall effect of light (SHEL) is studied in this paper. The proposed structure is composed of a glass layer, multilayer magnetized plasma layers, and an air layer. The multilayer magnetized plasma layers are arranged in accordance with the fifth Fibonacci sequence. The simulated results demonstrate that ωpa, ωpb (plasma frequencies of magnetized plasma for layers A and B), f (the frequency of the incident light), and the number of the magnetized plasma layers affect the behavior of non-reciprocity in the SHEL. The computed results also show that with the enhancement of ωpa, ωpb, and f, the phenomenon of non-reciprocity will be more obvious, evident by the distinct difference between the forward and backward incidence. However, the increase in the number of magnetized plasma layers has the effect of limiting the advantages of non-reciprocity in the SHEL. Those results demonstrate that the difference of δH (horizontal displacements) between the forward and backward incidence in the third sequence is 6 times greater than that in the fourth sequence, and the difference of δH in the fourth sequence is bigger than that in the fifth sequence. Through these findings, the non-reciprocity in the SHEL will be better understood and they will be of help in the development of optical isolators and non-reciprocal sensors.

12.
Appl Opt ; 60(5): 1448-1455, 2021 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-33690590

RESUMO

Simple periodic one-dimensional (1D) common photonic crystals (PCs) doped with InSb are proposed to research the Faraday rotation (FR) effect by applying a 4×4 transfer matrix method. Analysis indicates that the given 1D PCs can realize a giant FR angle. The influences of the properties of InSb (magnetic induction intensity, temperature, and the length of the InSb layer) and the repeat number of the structure on the FR are investigated due to the tunability of InSb and the features of the structure. Through calculation, it is found that, by adjusting these parameters, we can clearly observe the movement of the extreme values of the FR angle. In addition, the numerical results show that when the magnetic induction intensity and the repeat number of the structure are changed, the FR angle will be significantly altered at the fixed extreme frequency point. Specifically, if the temperature and the thickness of InSb layer are altered, the extreme value of the FR and the frequency point where it happens also will change. We believe these obtained results can provide ideas to design optical isolators and optical switches.

13.
Int J Mol Sci ; 22(16)2021 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-34445597

RESUMO

Spermatogenesis is a complicated process involving mitotically proliferating spermatogonial cells, meiotically dividing spermatocytes, and spermatid going through maturation into spermatozoa. The post-translational modifications of proteins play important roles in this biological process. S-palmitoylation is one type of protein modifications catalyzed by zinc finger Asp-His-His-Cys (ZDHHC)-family palmitoyl S-acyltransferases. There are 23 mammalian ZDHHCs that have been identified in mouse. Among them, Zdhhc19 is highly expressed in adult testis. However, the in vivo function of Zdhhc19 in mouse spermatogenesis and fertility remains unknown. In this study, we knocked out the Zdhhc19 gene by generating a 2609 bp deletion from exon 3 to exon 6 in mice. No differences were found in testis morphology and testis/body weight ratios upon Zdhhc19 deletion. Spermatogenesis was not disrupted in Zdhhc19 knockout mice, in which properly developed TRA98+ germ cells, SYCP3+ spermatocytes, and TNP1+ spermatids/spermatozoa were detected in seminiferous tubules. Nevertheless, Zdhhc19 knockout mice were male infertile. Zdhhc19 deficient spermatozoa exhibited multiple defects including abnormal morphology of sperm tails and heads, decreased motility, and disturbed acrosome reaction. All of these led to the inability of Zdhhc19 mutant sperm to fertilize oocytes in IVF assays. Taken together, our results support the fact that Zdhhc19 is a testis enriched gene dispensable for spermatogenesis, but is essential for sperm functions in mice.


Assuntos
Aciltransferases/fisiologia , Fertilização , Motilidade dos Espermatozoides , Espermatócitos/citologia , Espermatogênese , Espermatozoides/fisiologia , Reação Acrossômica , Animais , Feminino , Masculino , Camundongos , Camundongos Knockout , Espermatócitos/fisiologia
14.
Int J Mol Sci ; 22(24)2021 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-34948301

RESUMO

MFN1 (Mitofusin 1) and MFN2 (Mitofusin 2) are GTPases essential for mitochondrial fusion. Published studies revealed crucial roles of both Mitofusins during embryonic development. Despite the unique mitochondrial organization in sperm flagella, the biological requirement in sperm development and functions remain undefined. Here, using sperm-specific Cre drivers, we show that either Mfn1 or Mfn2 knockout in haploid germ cells does not affect male fertility. The Mfn1 and Mfn2 double knockout mice were further analyzed. We found no differences in testis morphology and weight between Mfn-deficient mice and their wild-type littermate controls. Spermatogenesis was normal in Mfn double knockout mice, in which properly developed TRA98+ germ cells, SYCP3+ spermatocytes, and TNP1+ spermatids/spermatozoa were detected in seminiferous tubules, indicating that sperm formation was not disrupted upon MFN deficiency. Collectively, our findings reveal that both MFN1 and MFN2 are dispensable for sperm development and functions in mice.


Assuntos
GTP Fosfo-Hidrolases/metabolismo , Espermatogênese/fisiologia , Espermatozoides/metabolismo , Animais , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mitocôndrias/metabolismo , Dinâmica Mitocondrial/fisiologia , Maturação do Esperma/fisiologia , Espermatócitos/metabolismo , Testículo/metabolismo
15.
Soft Matter ; 16(42): 9705-9711, 2020 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-32996541

RESUMO

In recent years, the use of dynamic chemical bonds to construct stimulus-responsive micelle systems has received increasing attention. However, current reports focus on the construction of dynamic covalent bond surfactants using dynamic chemical bonds, and the method of applying dynamic covalent bonds to hydrotropes has not been reported yet. In this study, a novel pH-responsive worm-like micelle system was constructed by mixing cetyltrimethylammonium bromide (CTAB), 4-hydroxybenzaldehyde (HB) and p-toluidine (MB) at the molar ratio of 60 mM : 40 mM : 40 mM. The formation mechanism of the dynamic covalent bond hydrotropes and the rheological behavior of the micelles were investigated via rheology, 1H-NMR spectroscopy and Cryo-TEM. The results show that as the pH increases, the viscosity of the solution first decreases and then increases rapidly. The microscopic aggregates in the solution transition from spherical micelles to worm-like micelles (WLMs), and the solution changes from a water-like fluid without viscosity to a gel system that can withstand its own weight. The transformation of the aggregates and their rheology can be attributed to the formation of MB-HB-, which is a type of hydrotrope with dynamic covalent bonds. Moreover, the transition from spherical micelles to worm-like micelles in this system is reversible.

16.
Soft Matter ; 16(16): 4024-4031, 2020 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-32270152

RESUMO

The gemini-like surfactants have been constructed by compounding N-erucamidopropyl-N,N-dimethylamine (UC22AMPM) and o-phthalic acid (o-PA), m-phthalic acid (m-PA), or p-phthalic acid (p-PA), and are denoted as o-EAPA, m-EAPA, and p-EAPA, respectively. It is well known that inorganic salts have significant effects on surfactant aggregates, and herein the effects of sodium chloride (NaCl) on gemini-like surfactants is explored by rheological and dynamic light scattering measurements, and cryo-TEM. It is found that the viscoelasticity of the EAPA systems first increases and then decreases with an increase of the NaCl concentration. And the optimal NaCl concentrations for these three systems are in the order of o-EAPA < m-EAPA < p-EAPA due to different spacer distances between the two carboxyl groups in the phthalic acid. Similar trends in the N,N-dimethyl oleoaminde-propylamine (DOAPA) and o-PA, m-PA, or p-PA systems were also observed. The results show that an appropriate NaCl concentration will promote gemini-like surfactants to form wormlike micelles (WLMs). Upon further increasing the NaCl concentration, the WLMs transform into vesicles. Excessive NaCl concentration will cause the surfactant systems to reach their cloud point and make the surfactants precipitate out. The mechanism of the effects of NaCl is that Cl- reduces the electrostatic repulsion between the headgroups of the surfactants. This work is helpful in understanding the effects of inorganic salts on the surfactants and this study is useful for exploring the practical applications of gemini-like surfactants.

17.
Int J Mol Sci ; 21(12)2020 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-32575410

RESUMO

Sertoli cells are somatic supporting cells in spermatogenic niche and play critical roles in germ cell development, but it is yet to be understood how epigenetic modifiers regulate Sertoli cell development and contribution to spermatogenesis. BRG1 (Brahma related gene 1) is a catalytic subunit of the mammalian SWI/SNF chromatin remodeling complex and participates in transcriptional regulation. The present study aimed to define the functions of BRG1 in mouse Sertoli cells during mouse spermatogenesis. We found that BRG1 protein was localized in the nuclei of both Sertoli cells and germ cells in seminiferous tubules. We further examined the requirement of BRG1 in Sertoli cell development using a Brg1 conditional knockout mouse model and two Amh-Cre mouse strains to specifically delete Brg1 gene from Sertoli cells. We found that the Amh-Cre mice from Jackson Laboratory had inefficient recombinase activities in Sertoli cells, while the other Amh-Cre strain from the European Mouse Mutant Archive achieved complete Brg1 deletion in Sertoli cells. Nevertheless, the conditional knockout of Brg1 from Sertoli cells by neither of Amh-Cre strains led to any detectable abnormalities in the development of either Sertoli cells or germ cells, suggesting that BRG1-SWI/SNF complex is dispensable to the functions of Sertoli cells in spermatogenesis.


Assuntos
DNA Helicases/genética , DNA Helicases/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Células de Sertoli/metabolismo , Testículo/crescimento & desenvolvimento , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Animais , Núcleo Celular/metabolismo , Células Cultivadas , Regulação da Expressão Gênica , Técnicas de Inativação de Genes , Masculino , Camundongos , Camundongos Knockout , Túbulos Seminíferos/metabolismo , Diferenciação Sexual , Espermatogênese , Espermatozoides/metabolismo , Testículo/metabolismo
18.
Soft Matter ; 15(15): 3160-3167, 2019 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-30865762

RESUMO

A worm-like micelle (WLM) system can be obtained by mixing long-chain cationic surfactants and polybasic organic acids in an aqueous solution. However, the effect of different organic acid structures on the rheological behavior of WLM systems has not been researched. Herein, a novel pH-responsive wormlike micelle system (EATA) was constructed by the complexation of N-erucamidopropyl-N,N-dimethylamine (UC22AMPM) and benzene tricarboxylic acid (TA) at a molar ratio of 3 : 1. UC22AMPM/citric acid (EACA) was also prepared to perform a comparison. The rheological behavior, aggregate transformation and thickening mechanism of EATA solutions were investigated by using rheological measurements, cryo-TEM, DLS, surface tension and 1H NMR. The results show that, at low pH, spherical micelles were formed and the EATA solution exhibited a lower viscosity than the EACA system due to the strong hydrophobicity of the phenyl groups of TA molecules, but the viscosity reaches 106 mP s at pH 4.80. Because of the lower pKa value of TA than CA, the viscosity of the EATA system drops sharply with the appearance of precipitates caused by the isoelectric point when the pH is greater than 4.80. In addition, by circularly changing the pH value several times, the wormlike micelles could maintain their original viscoelasticity without being weakened in the slightest.

19.
Soft Matter ; 15(12): 2703-2710, 2019 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-30816889

RESUMO

A dynamic covalent bond is widely used to fabricate stimuli responsive systems due to its reversible molecular recognition properties. In this study, we developed a pH-responsive morphology transition system based on a mixture of a cationic surfactant CTAB and two nonamphiphilic precursors, 4-hydroxybenzaldehyde (HB) and octylamine (OA), at a molar ratio of 100 : 60 : 60 (CTAB/HB/OA). The morphology transition of CTAB/HB/OA was characterized by 1H NMR spectroscopy, Fourier transform infrared spectroscopy, macroscopic appearance observation, dynamic light scattering, and rheological and cryo-TEM measurements. The phase behavior of CTAB/HB/OA solutions underwent transition from a water-like fluid to a transparent gel-like solution and then converted into a turbid low-viscosity solution upon increasing the pH. Upon increasing the pH from 4.93 to 7.99, the morphology was transformed from spherical micelles to wormlike micelles. Upon further increasing the pH to 12.02, the wormlike micelles gradually disappeared with the formation of vesicles. Thus, a morphology transition from micelles to vesicles can be triggered by varying the pH of CTAB/HB/OA solutions. This drastic variation in morphology behavior was attributed to the pH dependent ionization and formation of the anionic surfactant HB-OA-. Besides, over 3 cycles of morphological alternation among spherical micelles, wormlike micelles and vesicles of the CTAB/HB/OA solutions can be obtained by adjusting the pH.

20.
Analyst ; 144(19): 5866-5874, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31482879

RESUMO

To enhance the sensitivity of an aptasensor, a novel strategy was designed to develop an electrochemical aptasensor based on poly(3,4-ethylenedioxy thiophene)-gold nanoflower (PEDOT-AuNF) composites supported on a three-dimensional graphene oxide sponge (GOS). GOS with a three-dimensional sponge-like porous structure, exhibiting excellent electrical conductivity and a large surface area, provided the first amplification of the electrochemical signal for ochratoxin A (OTA) detection. PEDOT-AuNFs, synthesized by an ionic liquid-assisted one-pot method, presented a peculiar hierarchical flower-like structure, a high electroactive surface area, and more binding sites for immobilizing the aptamer molecules by the Au-S bonds. When PEDOT-AuNFs were supported on the surface of GOS by the interaction of the π-π packing between PEDOT and graphene oxide, a synergistic effect was produced to provide the second amplification for the aptasensor. PEDOT-AuNFs/GOS provided an ultrasensitive detection technique by multiple signal amplification for the electrochemical sensing of OTA. Consequently, this strategy not only endowed the aptasensor with high sensitivity but also needed no complicated signal amplification. The electrochemical sensor was fabricated successfully on a glassy carbon electrode to detect OTA with a linear response in the range of 0.01-20 ng L-1 and a limit of detection of 4.9 pg L-1. Moreover, it displayed good specificity, reproducibility and stability. The utilization of the proposed aptasensor for the quantitative determination of OTA in wine indicates that it can find promising applications in detecting OTA and even other mycotoxins in foodstuffs.


Assuntos
Aptâmeros de Nucleotídeos/química , Compostos Bicíclicos Heterocíclicos com Pontes/química , Grafite/química , Nanopartículas Metálicas/química , Ocratoxinas/análise , Polímeros/química , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Contaminação de Alimentos/análise , Ouro/química , Limite de Detecção , Reprodutibilidade dos Testes , Vinho/análise
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA