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1.
Med Image Anal ; 97: 103249, 2024 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-38963972

RESUMO

Image registration is an essential step in many medical image analysis tasks. Traditional methods for image registration are primarily optimization-driven, finding the optimal deformations that maximize the similarity between two images. Recent learning-based methods, trained to directly predict transformations between two images, run much faster, but suffer from performance deficiencies due to domain shift. Here we present a new neural network based image registration framework, called NIR (Neural Image Registration), which is based on optimization but utilizes deep neural networks to model deformations between image pairs. NIR represents the transformation between two images with a continuous function implemented via neural fields, receiving a 3D coordinate as input and outputting the corresponding deformation vector. NIR provides two ways of generating deformation field: directly output a displacement vector field for general deformable registration, or output a velocity vector field and integrate the velocity field to derive the deformation field for diffeomorphic image registration. The optimal registration is discovered by updating the parameters of the neural field via stochastic mini-batch gradient descent. We describe several design choices that facilitate model optimization, including coordinate encoding, sinusoidal activation, coordinate sampling, and intensity sampling. NIR is evaluated on two 3D MR brain scan datasets, demonstrating highly competitive performance in terms of both registration accuracy and regularity. Compared to traditional optimization-based methods, our approach achieves better results in shorter computation times. In addition, our methods exhibit performance on a cross-dataset registration task, compared to the pre-trained learning-based methods.

2.
Int J Biol Macromol ; : 133252, 2024 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-38945707

RESUMO

The short shelf life of Litchi is due to its rapid metabolism after being harvested. Refrigeration is not a suitable method for preserving litchi, as the browning process of litchi that has been cryogenic will accelerate when it is brought to room temperature. This study introduces an alginate-based coating as a solution to control the post-harvest metabolism of litchi. The coating achieves this by simultaneously establishing crosslink and percolation networks, both of which act as barriers. The percolation network is created using rod-like cellulose nanocrystals, which possess excellent percolation properties. This network effectively reduces moisture loss. Compared to the control group, the coated litchi exhibited a 38.1 % lower browning index and a 62.5 % lower decay rate. Additionally, the soluble solid content increased by 107.1 %. The inclusion of cellulose nanocrystals and the crosslinking of calcium ions enhanced the mechanical properties of the composite membrane. Specifically, the tensile strength and elongation at break increased by 70 % and 366 % respectively. As all the components in the coating are edible, it is environmentally friendly and safe for human consumption.

3.
J Mol Histol ; 55(1): 51-67, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38165566

RESUMO

Vagal nerve stimulation (VNS) provides a novel therapeutic strategy for injured hearts by activating cholinergic anti-inflammatory pathways. However, little information is available on the metabolic pattern and arteriogenesis of VSMCs after MI. VNS has been shown to stimulate the expression of CPT1α, CPT1ß, Glut1, Glut4 and SDF-1α in coronary VSMCs, decreasing the number of CD68-positive macrophages while increasing CD206-positive macrophages in the infarcted hearts, leading to a decrease in TNF-α and IL-1ß accompanied by a reduced ratio of CD68- and CD206-positive cells, which were dramatically abolished by atropine and mecamylamine in vivo. Knockdown of SDF-1α substantially abrogated the effect of VNS on macrophagecell alteration and inflammatory factors in infarcted hearts. Mechanistically, ACh induced SDF-1α expression in VSMCs in a dose-dependent manner. Conversely, atropine, mecamylamine, and a PI3K/Akt inhibitor completely eliminated the effect of ACh on SDF-1α expression. Functionally, VNS promoted arteriogenesis and improved left ventricular performance, which could be abolished by Ad-shSDF-1α. Thus, VNS altered the VSMC metabolism pattern and arteriogenesis to repair the infarcted heart by inducing SDF-1α expression, which was associated with the m/nAChR-Akt signaling pathway.


Assuntos
Infarto do Miocárdio , Estimulação do Nervo Vago , Ratos , Animais , Masculino , Proteínas Proto-Oncogênicas c-akt/metabolismo , Quimiocina CXCL12/metabolismo , Ratos Sprague-Dawley , Mecamilamina/uso terapêutico , Fosfatidilinositol 3-Quinases/metabolismo , Músculo Liso Vascular/metabolismo , Derivados da Atropina/uso terapêutico
4.
ACS Appl Mater Interfaces ; 14(46): 52508-52515, 2022 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-36350274

RESUMO

Lead halide perovskite materials have been emerging as promising candidates for high-performance optoelectronic devices. Significant efforts have sought to realize monocrystalline perovskite films on a large scale. Here, we epitaxially grow monocrystalline methylammonium lead tribromide (MAPbBr3) films on lattice-matched gallium arsenide (GaAs) substrates on a centimeter scale. In particular, a solution-processed lead(II) sulfide (PbS) layer provides a lattice-matched and chemical protective interface for the solid-gas reaction to form MAPbBr3 films on GaAs. Structure characterizations identify the crystal orientations in the trilayer MAPbBr3/PbS/GaAs epistructure and confirm the monocrystalline nature of MAPbBr3 on PbS/GaAs. The dynamic evolution of surface morphologies during the growth indicates a two-step epitaxial process. These fundamental understandings and practical growth techniques offer a viable guideline to approach high-quality perovskite films for previously inaccessible applications.

5.
PLoS One ; 17(4): e0266536, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35385538

RESUMO

For better understanding the genetic diversity and phylogeny of the cultivated Salvia miltiorrhiza populations, four intergenic spacer sequences, ETS, psbA-trnH, trnL-trnF, and ycf1-rps15 of the 40 populations collected from China were Polymerase Chain Reaction (PCR) amplified, analyzed both individually and in combination. Haplotype diversity analysis showed that the cultivated S. miltiorrhiza populations had a very rich genetic diversity and an excellent capacity to resist environmental pressure. The best-fit nucleotide substitution models for ETS, psbA-trnH, trnL-trnF, ycf1-rps15, and their combined sequences were HKY+I, T92, T92, T92+G, and T92+G, respectively; the nucleotide conversion frequency in the combined sequences was lower than the transversion, and the relatively high nucleotide substitution frequencies suggests its high genetic variability. Neutral tests showed that the spacer sequences of the populations conform with the neutral evolution model, and there has been no current expansion events occurred. Phylogeny analyses based on both the individual and the combined sequences showed that the 40 populations were clustered in two clades with a very similar topological structure. The discrimination rate of the combined sequence marker is significantly increased to 52.5% (21 populations) over the highest 35% (13 populations) by the single marker of ETS, though still inadequate but a big step forward. Further exploration of more DNA markers is needed. This study for the first time revealed the rich genetic diversity and phylogeny of the currently cultivated S. miltiorrhiza populations in China and provides novel alternative molecular markers for the genetic identification and resources evaluation of the cultivated S. miltiorrhiza populations.


Assuntos
Salvia miltiorrhiza , DNA Intergênico/genética , DNA de Plantas/genética , Variação Genética , Nucleotídeos , Filogenia , Salvia miltiorrhiza/genética , Análise de Sequência de DNA
6.
Front Neurosci ; 15: 683153, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34163327

RESUMO

PURPOSE: The current study was to investigate whether myopia affected peripheral motion detection and whether the potential effect interacted with spatial frequency, motion speed, or eccentricity. METHODS: Seventeen young adults aged 22-26 years participated in the study. They were six low to medium myopes [spherical equivalent refractions -1.0 to -5.0 D (diopter)], five high myopes (<-5.5 D) and six emmetropes (+0.5 to -0.5 D). All myopes were corrected by self-prepared, habitual soft contact lenses. A four-alternative forced-choice task in which the subject was to determine the location of the phase-shifting Gabor from the four quadrants (superior, inferior, nasal, and temporal) of the visual field, was employed. The experiment was blocked by eccentricity (20° and 27°), spatial frequency (0.6, 1.2, 2.4, and 4.0 cycles per degree (c/d) for 20° eccentricity, and 0.6, 1.2, 2.0, and 3.2 c/d for 27° eccentricity), as well as the motion speed [2 and 6 degree per second (d/s)]. RESULTS: Mixed-model analysis of variances showed no significant difference in the thresholds of peripheral motion detection between three refractive groups at either 20° (F[2,14] = 0.145, p = 0.866) or 27° (F[2,14] = 0.475, p = 0.632). At 20°, lower motion detection thresholds were associated with higher myopia (p < 0.05) mostly for low spatial frequency and high-speed targets in the nasal and superior quadrants, and for high spatial frequency and high-speed targets in the temporal quadrant in myopic viewers. Whereas at 27°, no significant correlation was found between the spherical equivalent and the peripheral motion detection threshold under all conditions (all p > 0.1). Spatial frequency, speed, and quadrant of the visual field all showed significant effect on the peripheral motion detection threshold. CONCLUSION: There was no significant difference between the three refractive groups in peripheral motion detection. However, lower motion detection thresholds were associated with higher myopia, mostly for low spatial frequency targets, at 20° in myopic viewers.

7.
Aging (Albany NY) ; 13(1): 894-909, 2020 11 26.
Artigo em Inglês | MEDLINE | ID: mdl-33260155

RESUMO

Glioma is a primary, malignant, and aggressive brain tumor in adults. To develop new therapeutic strategies for glioma, we must determine its underlying mechanisms. In the present study, we aimed to investigate the potential role of miR-1272-ADAM9-CDCP1 signaling in the progression of glioma. We found that ectopic expression of miR-1272 produced significant inhibitory effects on cell proliferation and migration and was associated with cell cycle G0/G1 arrest in A172 and SHG44 glioma cells. Using the luciferase reporter assay, we identified ADAM9 as a target of miR-1272. The expression of ADAM9 was markedly decreased or increased after overexpression or inhibition, respectively, of miR-1272 in glioma cells. Moreover, overexpression of ADAM9 reversed the inhibitory effects of miR-1272 on glioma cell progression. Furthermore, CDCP1 served as a potential downstream molecule of miR-1272/ADAM9 signaling in glioma and promoted the proliferation and migration of glioma. Results derived from clinical samples and online databases confirmed correlations between the expression of ADAM9 and CDCP1 and both the severity and prognosis of glioma. In conclusion, these results suggest that miR-1272 and CDCP1 may act as novel regulators in glioma. The miR-1272/ADAM9/CDCP1 pathway may serve as a potential candidate pathway for the prevention of glioma.


Assuntos
Proteínas ADAM/genética , Antígenos de Neoplasias/genética , Neoplasias Encefálicas/genética , Moléculas de Adesão Celular/genética , Glioma/genética , Proteínas de Membrana/genética , MicroRNAs/metabolismo , Proteínas ADAM/metabolismo , Antígenos de Neoplasias/metabolismo , Astrocitoma/genética , Astrocitoma/metabolismo , Astrocitoma/patologia , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Moléculas de Adesão Celular/metabolismo , Linhagem Celular , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células/genética , Progressão da Doença , Pontos de Checagem da Fase G1 do Ciclo Celular/genética , Glioblastoma/genética , Glioblastoma/metabolismo , Glioblastoma/patologia , Glioma/metabolismo , Glioma/patologia , Humanos , Proteínas de Membrana/metabolismo , MicroRNAs/genética , Transdução de Sinais
8.
Invest Ophthalmol Vis Sci ; 61(8): 1, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32609295

RESUMO

Purpose: The purpose of this study was to present our investigation of the influence of reduced monocular luminance on monocular and dichoptic temporal synchrony processing in healthy adults. Methods: Ten adults with normal or corrected to normal visual acuity participated in our psychophysical study. The temporal synchrony threshold in dichoptic (experiment 1), monocular (experiment 2), and binocular (experiment 3) viewing configurations was obtained from each observer. Four flickering Gaussian dots (one synchronous and one asynchronous pair of two dots) were displayed, from which the observers were asked to identify the asynchronous pair. The temporal phase lag in the signal pair (asynchronous) but not in the reference pair (synchronous) was varied. In addition, a neutral density (ND) filter of various intensities (1.3 and 2.0 log units) was placed before the dominant eye throughout the behavioral measurement. In the end, dichoptic, monocular, and binocular thresholds were measured for each observer. Results: With decreasing monocular luminance, the dichoptic threshold (2 ND vs. 0 ND, P < 0.001; 2 ND vs. 1.3 ND P = 0.001) and monocular threshold (2 ND vs. 0 ND, P < 0.001; 2 ND vs. 1.3 ND, P = 0.003) increased; however, the bincoular threshold remained unaffected (P = 0.576). Conclusions: Reduced luminance induces delay and disturbs the discrimination of temporal synchrony. Our findings have clinical implications in visual disorders.


Assuntos
Sensibilidades de Contraste/fisiologia , Potenciais Evocados Visuais/fisiologia , Limiar Sensorial/fisiologia , Lobo Temporal/fisiologia , Visão Monocular/fisiologia , Adulto , Feminino , Humanos , Masculino , Estimulação Luminosa , Psicofísica , Valores de Referência
9.
eNeuro ; 7(3)2020.
Artigo em Inglês | MEDLINE | ID: mdl-32345735

RESUMO

Action video gaming can promote neural plasticity. Short-term monocular patching drives neural plasticity in the visual system of human adults. For instance, short-term monocular patching of 0.5-5 h briefly enhances the patched eye's contribution in binocular vision (i.e., short-term ocular dominance plasticity). In this study, we investigate whether action video gaming can influence this plasticity in adults with normal vision. We measured participants' eye dominance using a binocular phase combination task before and after 2.5 h of monocular patching. Participants were asked to play action video games, watch action video game movies, or play non-action video games during the period of monocular patching. We found that participants' change of ocular dominance after monocular patching was not significantly different either for playing action video games versus watching action video game movies (Comparison 1) or for playing action video games versus playing non-action video games (Comparison 2). These results suggest that action video gaming does not either boost or eliminate short-term ocular dominance plasticity, and that the neural site for this type of plasticity might be in the early visual pathway.


Assuntos
Jogos de Vídeo , Adulto , Dominância Ocular , Humanos , Plasticidade Neuronal , Visão Monocular , Vias Visuais
10.
Nanoscale ; 12(13): 7263-7272, 2020 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-32196021

RESUMO

The perovskite structure provides a versatile framework for functional materials and their high-quality heteroepitaxial interfaces. Perovskite halides (PH) have attracted intense interest for their application in optoelectronics. Oxides are another major class of perovskites that are widely used in fuel cells, nonconventional electronics and electrochemistry. Interfacing different perovskite oxides (POs) has led to a multitude of fascinating discoveries. By introducing anionic degree of freedom, we expect that perovskite hetero-anionic-sublattice interfaces can provide a new platform for emergent phenomena that may or may not have homo-oxygen-sublattice interface analogues. In this work, we investigate the interfaces between the all-inorganic PH CsPbBr3, the emerging double perovskite halide (dPH) Cs2TiBr6 and various common POs. Based on the band alignment properties, these POs are considered to be suitable carrier transport materials (CTMs) for CsPbBr3 and Cs2TiBr6 in either light-harvesting or light-emitting devices. In addition, these perovskite hetero-anionic-sublattice interfaces are found to be defect- and dangling bond-free due to compatible crystal lattices, making POs potentially outperform conventional binary transition-metal-oxide and organic CTMs. Besides optoelectronics, the potential of perovskite hetero-anionic-sublattice interfaces for nonconventional electronics is also explored. As examples, two-dimensionally confined electron-hole systems are predicted at the asymmetric interfaces in both Cs2TiBr6:LaAlO3 and CsPbBr3:LaAlO3 superlattice structures. This finding, along with the optically active properties of PHs, may spark novel applications of light-electron interaction in perovskite systems. This work presents new opportunities for perovskite heteroepitaxial interfaces.

11.
ACS Appl Mater Interfaces ; 11(19): 18013-18023, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-31010291

RESUMO

Biodegradable electronic devices that physically disappear in physiological or environmental solutions are of critical importance for widespread applications in healthcare management and environmental sustainability. The precise modulation of materials and devices dissolution with on-demand operational lifetime, however, remain a key challenge. Silicon nanomembranes (Si NMs) are one of the essential semiconductor components for high-performance biodegradable electronics at the system level. In this work, we discover unusual hydrolysis behaviors of Si NMs that are significantly dependent on the dimensions of devices as well as their surface chemistry statuses. The experiments show a pronounced increase in hydrolysis rates of p-type Si NMs with larger sizes, and mechanical stirring introduces a significant decrease in dissolution rates. The presence of phosphates and potassium ions in solutions, or lower dopant levels of Si NMs will facilitate the degradation of Si NMs and will also lead to a stronger size-dependent effect. Molecular dynamics simulations are performed to reveal ion adsorption mechanisms of Si NMs under different surface charge statuses and confirm our experimental observations. Through geometrical designs, Si NM-based electrode arrays with tunable dissolution lifetime are formed, and their electrochemical properties are analyzed in vitro. These results offer new controlling strategies to modulate the operational time frames of Si NMs through geometrical design and surface chemistry modification and provide crucial fundamental understandings for engineering high-performance biodegradable electronics.


Assuntos
Membranas Artificiais , Nanoestruturas/química , Silício/química , Cristalização , Eletrônica , Hidrólise/efeitos dos fármacos , Íons/química , Semicondutores
12.
Am J Transl Res ; 11(12): 7568-7578, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31934301

RESUMO

Glioma is a common malignant human brain tumor. The progression of glioma is associated with dysregulation of various microRNAs. Previous studies have demonstrated that microRNA-26b-3p (miR-26b-3p) is correlated with the pathogenesis of various tumors, but the functional role of miR-26b-3p and its underlying mechanisms in glioma are not clear. Here, we found that overexpression of miR-26b-3p repressed cell migration and proliferation and promoted apoptosis. In contrast, the opposite effects were observed when miR-26b-3p was inhibited in glioma cells. Anthrax toxin receptor 1 (ANTXR1) was confirmed to be a downstream molecule of miR-26b-3p. Reintroduction of ANTXR1 with an ORF region rescued the suppressive effects of miR-26b-3p on proliferation and migration, and inhibited the apoptosis of glioma cells. Moreover, the downstream target of miR-26b-3p, ANTXR1, was increased in glioma tissues and was inversely correlated with miR-26b-3p. MiR-26b-3p and ANTXR1 were correlated with the severity of glioma. Taken together, these results demonstrate that miR-26b-3p is a critical modulator of glioma via its downstream molecule, ANTXR1. Further, the miR-26b-3p/ANTXR1 axis may serve as a treatment or diagnostic target in glioma.

13.
Electrophoresis ; 39(22): 2912-2918, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30194854

RESUMO

Because of unique properties like permanent porosity, low density and large surface area, covalent organic frameworks are attractive microporous materials as stationary phase for CEC. Among them, COF-TpPa-1 possesses extraordinary chemical stability and common features of covalent organic frameworks. So, COF-TpPa-1 could be a promising material as stationary phase to enhance separation selectivity and tolerate the acid or alkaline electrochromatographic separation conditions. Here, we report the preparation of COF-TpPa-1 modified capillary column by in situ growth for electrochromatographic separation. The immobilization of COF-TpPa-1 on the inner wall of capillary column was confirmed by Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction. The fabricated COF-TpPa-1 modified capillary column indicated good resolution for the separation of neutral analytes, nonsteroidal anti-inflammatory drugs and food additives in open-tubular CEC mode. Compared with bare capillary column, the COF-TpPa-1 modified capillary column improved separation selectivity remarkably for tested analytes, including hydrophobic, π-π and hydrogen bond interactions. Besides, the prepared capillary column showed excellent repeatability and stability. The intraday, interday and column-to-column relative standard deviations of migration time for neutral analytes were less than 3.54%. This work shows enamine-linked covalent organic frameworks have great potential as stationary phases in CEC.


Assuntos
Eletrocromatografia Capilar/métodos , Aditivos Alimentares/isolamento & purificação , Estruturas Metalorgânicas/química , Preparações Farmacêuticas/isolamento & purificação , Aditivos Alimentares/análise , Concentração de Íons de Hidrogênio , Metanol , Preparações Farmacêuticas/análise , Reprodutibilidade dos Testes
14.
Bioact Mater ; 3(3): 322-333, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29744469

RESUMO

Transient electronics (or biodegradable electronics) is an emerging technology whose key characteristic is an ability to dissolve, resorb, or physically disappear in physiological environments in a controlled manner. Potential applications include eco-friendly sensors, temporary biomedical implants, and data-secure hardware. Biodegradable electronics built with water-soluble, biocompatible active and passive materials can provide multifunctional operations for diagnostic and therapeutic purposes, such as monitoring intracranial pressure, identifying neural networks, assisting wound healing process, etc. This review summarizes the up-to-date materials strategies, manufacturing schemes, and device layouts for biodegradable electronics, and the outlook is discussed at the end. It is expected that the translation of these materials and technologies into clinical settings could potentially provide vital tools that are beneficial for human healthcare.

15.
J Pain Res ; 11: 615-628, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29628771

RESUMO

OBJECTIVE: The dorsal horn P2Y13 receptor is involved in the development of pain behavior induced by peripheral nerve injury. It is unclear whether the expression of proinflammatory cytokines interleukin (IL)-1ß and IL-6 at the spinal dorsal horn are influenced after the activation of P2Y13 receptor in rats with diabetic neuropathic pain (DNP). METHODS: A rat model of type 1 DNP was induced by intraperitoneal injection of streptozotocin (STZ). We examined the expression of P2Y13 receptor, Iba-1, IL-1ß, IL-6, JAK2, STAT3, pTyr1336, and pTyr1472 NR2B in rat spinal dorsal horn. RESULTS: Compared with normal rats, STZ-diabetic rats displayed obvious mechanical allodynia and the increased expression of P2Y13 receptor, Iba-1, IL-1ß, and IL-6 in the dorsal spinal cord that was continued for 6 weeks in DNP rats. The data obtained indicated that, in DNP rats, administration of MRS2211 significantly attenuated mechanical allodynia. Compared with DNP rats, after MRS2211 treatment, expression of the P2Y13 receptor, Iba-1, IL-1ß, and IL-6 were reduced 4 weeks after the STZ injection. However, MRS2211 treatment did not attenuate the expression of the P2Y13 receptor, Iba-1, IL-1ß, and IL-6 at 6 weeks after the STZ injection. MRS2211 suppressed JAK2 and STAT3 expression in the early stage, but not in the later stage. Moreover, pTyr1336 NR2B was significantly decreased, whereas pTyr1472 NR2B was unaffected in the dorsal spinal cord of MRS2211-treated DNP rats. CONCLUSION: Intrathecal MRS2211 produces an anti-nociceptive effect in early-stage DNP. A possible mechanism involved in MRS2211-induced analgesia is that blocking the P2Y13 receptor downregulates levels of IL-1ß and IL-6, which subsequently inhibit the activation of the JAK2/STAT3 signaling pathway. Furthermore, blocking the activation of the P2Y13 receptor can decrease NR2B-containing NMDAR phosphorylation in dorsal spinal cord neurons, thereby attenuating central sensitization in STZ-induced DNP rats.

16.
Electrophoresis ; 39(2): 363-369, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28891068

RESUMO

Pillar[n]arenes have achieved much interest in material chemistry and supramolecular chemistry due to unusual pillar shape structure and high selectivity toward guest. However, pillar[n]arenes have not yet been applied in capillary electrochromatography. This work at first time reports that carboxylatopillar[5]arene is used as a stationary phase in open-tubular capillary electrochromatography. Carboxylatopillar[5]arene not only possess the advantages of pillar[n]arenes but also provide free carboxy groups for immobilizing on the inner wall of capillary column via covalent bonding. The characterization of SEM and FT-IR indicated that carboxylatopillar[5]arene was successfully grafted on the inner wall of capillary. The baseline separation of model analytes including neutral, basic, and acidic compounds, nonsteroidal anti-inflammatory drugs and dansyl-amino acids have been achieved thanks to the electron-rich cavity of carboxylatopillar[5]arene and hydrophobic interactions between the analytes and stationary phase. The intraday, interday, and column-to-column precisions (RSDs) of retention time and peak area for the neutral analytes were all less than 3.34 and 9.65%, respectively. This work indicates that pillar[n]arenes have great potential in capillary electrochromatography as novel stationary phase.


Assuntos
Eletrocromatografia Capilar/instrumentação , Eletrocromatografia Capilar/métodos , Compostos de Amônio Quaternário/química , Aminoácidos/análise , Anti-Inflamatórios não Esteroides/análise , Cromatografia Líquida de Alta Pressão , Reprodutibilidade dos Testes , Espectroscopia de Infravermelho com Transformada de Fourier
18.
Biol Reprod ; 96(1): 254-265, 2017 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-28395332

RESUMO

The insecticide acetamiprid is used to control noxious agricultural pests. However, it can cause mammalian toxicity. We evaluated the reproductive toxicity of acetamiprid in adult male Sprague Dawley rats. Rats were given oral acetamiprid alone or with vitamin E for 35 days. Rat plasma testosterone concentration and sperm quality decreased significantly as the levels of luteinizing hormone (LH) increased after exposure. At the same time, acetamiprid increased malondialdehyde and nitric oxide (NO) levels of Leydig cells. Further analysis showed that acetamiprid reduced the adenosine triphosphate (ATP) and cyclic adenosine monophosphate (cAMP) production of Leydig cells, but the expression of luteinizing hormone/choriogonadotropin receptor (LHCGR) and the activity of adenylyl cyclase were not changed. Acetamiprid exposure also significantly diminished protein levels of steroidogenic acute regulatory protein (STAR), hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase cluster (HSD3B), and cytochrome P450, family 11, subfamily a, polypeptide 1 (CYP11A1), and testicular mRNA levels, which are cAMP-dependent proteins that are essential for steroidogenesis. Electron microscopy indicated mitochondrial membrane damage in the Leydig cells of the testes of exposed rats. Vitamin E ameliorated the impairment of acetamiprid on Leydig cells. Our results indicate that acetamiprid causes oxidative stress and mitochondrial damage in Leydig cells and inhibits the synthesis of testicular ATP and cAMP. Acetamiprid disrupts subsequent testosterone biosynthesis by decreasing the rate of conversion of cholesterol to testosterone and by preventing cholesterol from entering the mitochondria within the Leydig cells. These effects caused reproductive damage to the rats.


Assuntos
Inseticidas/toxicidade , Células Intersticiais do Testículo/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Neonicotinoides/toxicidade , Testosterona/metabolismo , Trifosfato de Adenosina/metabolismo , Adenilil Ciclases/metabolismo , Animais , Peso Corporal , AMP Cíclico/metabolismo , Inseticidas/sangue , Células Intersticiais do Testículo/metabolismo , Hormônio Luteinizante/sangue , Masculino , Neonicotinoides/sangue , Estresse Oxidativo/efeitos dos fármacos , Fosfoproteínas/metabolismo , Ratos Sprague-Dawley , Receptores do LH/metabolismo , Motilidade dos Espermatozoides , Testosterona/biossíntese , Testosterona/sangue
19.
J Sep Sci ; 40(9): 2030-2036, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28244204

RESUMO

Bisphosphonates are a class of chemical compounds used to treat diseases caused by increased bone resorption. Zoledronate is a third-generation bisphosphonate drug. Hydroxyapatite is main mineral constituent of bones, which can be bound by bisphosphonates in vivo. In this work, we report a method of nonlinear capillary electrochromatography for study on the interaction between hydroxyapatite and bisphosphonate. Hydroxyapatite was modified on the inner wall of capillary by a biomimetic-mineralization method. Then nonlinear chromatography was used to fit and analyze the interaction between zoledronate and hydroxyapatite. The association rate constants of zoledronate in hydroxyapatite-modified capillary and bare capillary are 642.3 and 195/M/min, respectively. This indicates that there is strong binding interactions and affinity between zoledronate and hydroxyapatite. Besides, the interaction between zoledronate and hydroxyapatite was confirmed further by ultraviolet spectroscopy. The method of nonlinear capillary electrochromatography provides a fast and effect approach for studying of bone metabolism disease by evaluation of interaction between hydroxyapatite and bisphosphonates.


Assuntos
Difosfonatos/química , Durapatita/química , Imidazóis/química , Osso e Ossos , Eletrocromatografia Capilar , Ácido Zoledrônico
20.
J Chromatogr A ; 1445: 140-8, 2016 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-27062718

RESUMO

Covalent-organic frameworks (COFs) are attractive materials for their fascinating properties, such as rigid structures, exceptional thermal stabilities, low densities, and permanent porosity with specific surface areas, which indicate potential for application in chromatography similar to related metal-organic frameworks (MOFs). However, the utilization of COFs in analytical chemistry is far behind as compared to that of the MOFs due to the challenging work of their immobilization. Here, we have successfully demonstrated the growth of the boron COF-5 on the inner wall of the fused silica capillary by a developed polydopamine-supported method. Combined with the layer-by-layer strategy, multilayer COF-5-coated capillary was obtained. The formation of COF-5 on polydopamine-coated substrate has been confirmed by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction. A novel stationary phase of COF-5 was developed on the basis of successful growth of COF-5 on polydopamine for open-tubular capillary electrochromatography (OT-CEC). Baseline separation of neutral, acidic and basic analytes was achieved on multilayer COF-5-coated capillary column. The fabricated capillary columns showed high column efficiency (154,060 plates/m for methylbenzene), excellent stability and repeatability. The precision (relative standard deviation (RSD), n=3) of retention time, peak height, and peak area for tested neutral compounds were in the range of 1.2-1.3%, 1.8-4.2%, and 0.9-2.4%, respectively. To the best of our knowledge, it was the first demonstration that COF-5 was developed as a novel stationary phase.


Assuntos
Eletrocromatografia Capilar/instrumentação , Eletrocromatografia Capilar/métodos , Indóis/química , Polímeros/química , Microscopia Eletrônica de Varredura , Porosidade , Dióxido de Silício/química , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
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