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1.
J Hepatocell Carcinoma ; 8: 1389-1397, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34824998

RESUMO

The Rab GTPase family contains almost 70 genes in the human genome and acts as the key regulator of intracellular membrane trafficking in human cells. The dysregulation of Rab GTPase has been shown to be associated with multiple human diseases, ranging from neurodegeneration, and infection to cancer. Rab GTPases not only play important roles in genome replication, morphogenesis and the release of hepatitis B virus (HBV) or hepatitis C virus (HCV), but also contribute to hepatitis-related hepatocarcinogenesis and hepatocellular carcinoma (HCC) progression. The alteration of Rab GTPase expression in HCC plays an important role in tumour cell proliferation, invasion and migration. Notably, the expression of Rab genes can be regulated by some noncoding RNAs, such as miRNAs and circRNAs. Thus, Rab GTPases can serve as promising rational and therapeutic targets for HCC treatments. In this review, we summarized recent advancements in this field focusing on Rab GTPases in HCC.

2.
Front Immunol ; 12: 733530, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34659220

RESUMO

Background and Aim: Immune checkpoint inhibitors (ICIs) have been widely used in hepatocellular carcinoma (HCC), while only a subset of patients experience clinical benefit. We aimed to investigate the effects of viral etiology on response to ICIs in HCC and depict the tumor immune microenvironment (TIME) of virally infected and uninfected HCC. Methods: A systematic search was conducted in PubMed, Web of Science, Embase, and the Cochrane central register of controlled trials up to August 2021. Clinical trials reporting the efficacy of ICIs in HCC were eligible. Baseline characteristics including first author, year of publication, National Clinical Trials (NCT) registry number, study region, sample sizes, interventions, line of treatment, and viral status were extracted. Meta-analysis was conducted to generate combined odds ratios (ORs) with 95% confidence intervals (CI) based on random or fixed effect model, depending on heterogeneity. Tumor immune microenvironment was depicted using ESTIMATE and CIBERSORT algorithm. Results: Eight studies involving 1,520 patients were included. Combined data suggested that there was no significant difference of objective response rate (ORR) between virally infected HCC and non-viral HCC patients [OR = 1.03 (95% CI, 0.77-1.37; I2 = 30.9%, pH = 0.152)]. Similarly, difference was not observed on ORR between HBV-HCC and HCV-HCC patients [OR = 0.74 (95% CI, 0.52-1.06; I2 = 7.4%, pH = 0.374)]. The infiltration of immune cells in the tumor microenvironment did not differ by etiology except for M0 macrophages, M2 macrophages, regulatory T cells, naive B cells, follicular helper T cells, activated dendritic cells, activated mast cells, and plasma cells. Despite differences in infiltration observed in specific cell types, the immune score and stromal score were generally comparable among etiology groups. Conclusion: Viral etiology may not be considered as the selection criteria for patients receiving ICIs in HCC, and viral status has little impact on TIME remodeling during HCC tumorigenesis.

3.
Polymers (Basel) ; 13(12)2021 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-34208259

RESUMO

Literature has reported the successful use of 3D printed polyetheretherketone (PEEK) to fabricate human body implants and oral prostheses. However, the current 3D printed PEEK (brown color) cannot mimic the vivid color of oral tissues and thus cannot meet the esthetical need for dental application. Therefore, titanium dioxide (TiO2) and ferric oxide (Fe2O3) were incorporated into PEEK to prepare a series of tooth-color and gingival-color PEEK composites in this study. Through color measurements and mechanical tests, the color value and mechanical performance of the 3D printed PEEK composites were evaluated. In addition, duotone PEEK specimens were printed by a double nozzle with an interface between tooth-color and gingival-color parts. The mechanical performance of duotone PEEK with two different interfaces (horizontal and vertical) was investigated. With the addition of TiO2 and Fe2O3, the colors of 3D printed PEEK composites become closer to that of dental shade guides. 3D printed PEEK composites generally demonstrated superior tensile and flexural properties and hence have great potential in the dental application. In addition, duotone 3D printed PEEK with a horizontal interfacial orientation presented better mechanical performance than that with a vertical one.

4.
J Cancer ; 12(13): 3827-3840, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34093791

RESUMO

Angiogenesis and immunosuppression have been described as closely related processes that can occur in parallel. As an inhibitor of matrix metalloproteinase, whether the level of reversion-inducing cysteine-rich protein with Kazal motifs (RECK) in hepatocellular carcinoma (HCC) reflects a link between angiogenesis and immunosuppression is still unknown. We analyzed RNA expression, immune infiltration and survival of HCC from The Cancer Genome Atlas databases. Immune scores and stromal scores were calculated based on the ESTIMATE algorithm to quantify the immune and stromal components in HCC. The association between RECK and clinicopathological features was further investigated by immunohistochemistry on tissue microarray. We found that the prognosis of patients with high RECK expression was significantly better than that of patients with low RECK expression. High RECK expression was associated with high ESTIMATE Score, recruitment of more tumor-infiltrating lymphocytes, low tumor purity, and high PD-L1 expression. In addition, positive RECK expression was associated with a lower incidence of vascular invasion and recurrence, a lower level of alpha fetoprotein (AFP) and microvessel density and a better tumor differentiation. Multivariate analyses revealed that reduced RECK expression was an independent prognostic factor for recurrence and poor prognosis. In conclusion, high RECK expression reflects an immunogenic and hypovascularity status in HCC. RECK is a promising prognostic marker for survival of HCC and may act as a complementary indicator for patients to receive anti-angiogenic therapy or immunotherapy.

5.
Exp Ther Med ; 21(4): 348, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33732321

RESUMO

The present study aimed to evaluate the biomechanical behavior of a custom 3D-printed polyetheretherketone (PEEK) condylar prosthesis using finite element analysis and mechanical testing. The Mimics software was used to create a 3D model of the mandible, which was then imported into Geomagic Studio software to perform osteotomy of the lesion area. A customized PEEK condyle prosthesis was then designed and the finite element model of the PEEK condyle prosthesis, mandible and fixation screw was established. The maximum stress of the prosthesis and screws, as well as stress and strain of the cortical and cancellous bones in the intercuspal position, incisal clench, left unilateral molar clench and right unilateral molar clench was analyzed. The biomechanical properties of the prosthesis were studied using two models with different lesion ranges. To simulate the actual clinical situation, a special fixture was designed. The compression performance was tested at 1 mm/min for the condyle prosthesis, prepared by fused deposition modeling (FDM). The results of a finite element analysis suggested that the maximum stress of the condyle was 10.733 MPa and the maximum stress of the screw was 9.7075 MPa; both were far less than the yield strength of the material. The maximum force that the two designed prostheses were able to withstand was 3,814.7±442.6 N (Model A) and 4,245.7±348.3 N (Model B). Overall, the customized PEEK condyle prostheses prepared by FDM exhibited a uniform stress distribution and good mechanical properties, providing a theoretical basis for PEEK as a reconstruction material for repairing the temporomandibular joint.

6.
Front Oncol ; 11: 605648, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33680960

RESUMO

Background and Aims: The clinical benefit of adjuvant antiviral therapy after curative therapy for HCC in patients with high preoperative HBV-DNA loads has been studied widely but that in patients with low preoperative HBV-DNA loads remains controversial. The purpose of this study was to determine the effect of antiviral treatment prophylaxis on HBV reactivation, overall survival (OS), and postoperative liver function in patients with low preoperative HBV-DNA levels undergoing curative resection. Methods: A meta-analysis was conducted by searching Web of Science, PubMed, Embase, and Cochrane Library until May 2020. We used REVMAN for data analysis and completed the study under the PRISMA guidelines. Results: Three randomized trials and seven cohort studies, comprising of 1,131 individuals, were included in the meta-analysis. Antiviral treatment significantly reduced the rate of HBV reactivation after curative treatment of HCC, with a pooled risk ratio of 0.12 (95% c.i. 0.07 to 0.21; P < 0.00001). The trials were consistently favorable for the antiviral group, with a pooled hazard ratio of 0.52 (95% c.i. 0.37 to 0.74; P = 0.0002) in respect of OS rate. However, by pooling the data from studies that reported ALT on the 30th day postoperatively, the result didn't reach statistical significance (mean difference -4.38, 95% c.i. -13.83 to 5.07; P = 0.36). The I² values of the heterogeneity test for the above three comparisons are zero. Conclusion: Antiviral therapy during curative resection is effective in reducing HBV reactivation and improving OS rate in HCC patients with low viral load.

7.
J Mech Behav Biomed Mater ; 118: 104475, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33773239

RESUMO

Polyether-ether-ketone (PEEK) exhibits excellent mechanical properties and biocompatibility. Three-dimensional (3D) printing of PEEK bone substitutes has been widely used in clinical application. However, the inertness of pure PEEK hinders its integration with the surrounding bone tissue. In this study, for the first time, PEEK/hydroxyapatite (HA) composite specimens were fabricated using fused filament fabrication (FFF) technology. PEEK/HA filaments with HA contents of 0-30 wt% were fabricated via mechanical mixing and extrusion. The HA distributions inside the composite matrix and the surface morphology characteristics of the PEEK/HA composites were examined. The effects of the printing path and HA content on the mechanics of the PEEK/HA composites were systematically investigated. The results indicated that the HA particles were uniformly distributed on the composite matrix. With an increase in the HA content, the modulus of the PEEK/HA composite increased, while the strength and failure strain concomitantly decreased. When the HA content increased to 30 wt%, the tensile modulus of the composite increased by 68.6% compared with that of pure PEEK printed along the horizontal 90° path, while the tensile strength decreased by 48.2% compared with that of pure PEEK printed along the vertical 90° path. The fracture elongation of the printed specimens with different HA contents decreased in the following order: horizontal 0° > horizontal 90° > vertical 90°. The best comprehensive mechanical properties were achieved for pure PEEK fabricated along the horizontal 0° path. The results indicate that FFF technology is applicable for additive manufacturing of PEEK/HA composites with controllable compositions. Printed PEEK/HA composites have potential for applications in the design and manufacturing of personalized bone substitutes.


Assuntos
Materiais Biocompatíveis , Durapatita , Éteres , Cetonas , Polietilenoglicóis , Impressão Tridimensional
8.
J Gastroenterol Hepatol ; 36(6): 1487-1496, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33393670

RESUMO

BACKGROUND AND AIM: The role of hypoxia-inducible factor-1α (HIF-1α) and hypoxia-inducible factor-2α (HIF-2α) has been implicated in the clinical prognosis of hepatocellular carcinoma (HCC), but the results remain controversial. We aim to investigate the association of HIF-1α and HIF-2α overexpression with the prognosis and clinicopathological features of HCC. METHODS: A systematic search was conducted in PubMed, Embase, Scopus, Web of Science, and Cochrane Library until June 20, 2020. Meta-analysis was conducted to generate combined HRs with 95% confidence intervals (CI) for overall survival (OS) and disease-free survival (DFS). Odds ratios (ORs) with 95% CI were also derived by fixed or random effect model. RESULTS: Twenty-two studies involving 3238 patients were included. Combined data suggested that overexpression of HIF-1α in HCC was not only correlated with poorer OS [HR = 1.75 (95% CI: 1.53-2.00)] and DFS [HR = 1.64 (95% CI: 1.34-2.00)] but was also positively associated with vascular invasion [OR = 1.83 (95% CI: 1.36-2.48)], tumor size [OR = 1.36 (95% CI: 1.12-1.66)], and tumor number [1.74 (95% CI: 1.34-2.25)]. In contrast, HIF-2α overexpression was not associated with the prognosis and clinicopathological features of HCC. CONCLUSION: Our data provided compelling evidence of a worse prognosis of HCC in HIF-1α overexpression patients but not HIF-2α overexpression ones.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Carcinoma Hepatocelular/genética , Expressão Gênica , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Neoplasias Hepáticas/genética , Carcinoma Hepatocelular/mortalidade , Feminino , Humanos , Neoplasias Hepáticas/mortalidade , Masculino , Prognóstico , Taxa de Sobrevida
9.
J Invest Surg ; 34(4): 366-372, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31304819

RESUMO

OBJECTIVE: The aim of this study was to investigate the role of matrix metallopeptidase 12 (MMP-12) in the development of hepatocellular carcinoma (HCC). Materials and Methods: A total of 343 HCC patients were retrospectively analyzed. MMP-12 expression was detected by immunohistochemical staining and the correlation between MMP-12 expression and clinical features was analyzed. Serum interleukin-6 (IL-6) and IL-10 levels were detected by an enzyme-linked immunosorbent assay (ELISA). Survival analysis was performed using the Kaplan-Meier method and PD-L1 expression in T cells was detected by flow cytometry. Results: MMP-12 expression in HCC tissues showed no correlation with age, gender, viral infection, cirrhosis, Child-Pugh score, alpha-fetoprotein levels, or Barcelona-Clinic Liver Cancer stage. However, higher levels of MMP-12 expression were correlated with increased tumor size, poorer tumor cell differentiation, higher TNM stage, and poorer prognosis. Moreover, MMP-12 expression was positively correlated with PD-L1 expression. Further analysis indicated that the regulation of PD-L1 expression by MMP-12 may occur through the IL-6-signaling pathway. Conclusions: Higher levels of MMP-12 expression indicated a poorer prognosis. PD-L1 expression was positively correlated with MMP-12 expression, indicating that MMP-12 may promote the development of HCC through the up-regulation of PD-L1.

10.
J Cancer ; 11(14): 4007-4014, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32368282

RESUMO

The E3 ubiquitin ligase TRIM4 has been reported to regulate the assembly of the antiviral signalling complex, induce mitochondrial aggregation and sensitize cells to H2O2-induced death. However, the relationship between TRIM4 and human malignancies, including hepatocellular carcinoma (HCC), is unclear. In this study, we detected the expression of TRIM4 in 134 pairs of HCC tissues and peritumoural tissues and investigated the association of TRIM4 expression with the prognosis of HCC. We found that the TRIM4 expression was much lower in HCC tissues than in peritumoural tissues and was significantly associated with vascular invasion, tumour capsule and Hong Kong Liver Cancer (HKLC) stage. Univariate and multivariate analyses revealed that the TRIM4 expression was an independent prognostic factor for overall survival (OS) and recurrence-free survival (RFS) in our HCC cohort. Patients with higher TRIM4 expression had a lower incidence of intrahepatic recurrence and a higher OS rate (p<0.001 and p<0.01, respectively). These results were further validated in another independent cohort of 200 HCC patients. In conclusion, the TRIM4 level in HCC tissues is an independent prognostic factor for HCC patients. Close clinical monitoring is recommended for patients with low TRIM4 expression.

11.
Phys Chem Chem Phys ; 21(27): 15187-15194, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31249995

RESUMO

In past decades, there have been great achievements on theoretical prediction and experimental fabrication of two-dimensional transition metal carbides. In this work, we report a hitherto unknown atomic-thin planar-structured transition metal carbide sheet denoted as MC6 (M = Cu, Ag, Au) via a structure-swarm intelligence algorithm. The proposed 2D crystals are both statically and dynamically stable, and could maintain their structure integrity at temperatures up to 1500 K. The calculated specific capacities of lithium-ion batteries employing such materials reach 1188 mA h g-1, which is 26.38% higher than previously reported highest MXene material with Mn+1Xn atomic configuration. Our results present the potential application of MC6 in Li-ion batteries.

12.
J Clin Med ; 8(2)2019 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-30759863

RESUMO

Fused deposition modeling (FDM) is a rapidly growing three-dimensional (3D) printing technology and has great potential in medicine. Polyether-ether-ketone (PEEK) is a biocompatible high-performance polymer, which is suitable to be used as an orthopedic/dental implant material. However, the mechanical properties and biocompatibility of FDM-printed PEEK and its composites are still not clear. In this study, FDM-printed pure PEEK and carbon fiber reinforced PEEK (CFR-PEEK) composite were successfully fabricated by FDM and characterized by mechanical tests. Moreover, the sample surfaces were modified with polishing and sandblasting methods to analyze the influence of surface roughness and topography on general biocompatibility (cytotoxicity) and cell adhesion. The results indicated that the printed CFR-PEEK samples had significantly higher general mechanical strengths than the printed pure PEEK (even though there was no statistical difference in compressive strength). Both PEEK and CFR-PEEK materials showed good biocompatibility with and without surface modification. Cell densities on the "as-printed" PEEK and the CFR-PEEK sample surfaces were significantly higher than on the corresponding polished and sandblasted samples. Therefore, the FDM-printed CFR-PEEK composite with proper mechanical strengths has potential as a biomaterial for bone grafting and tissue engineering applications.

13.
Nanoscale Res Lett ; 13(1): 378, 2018 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-30470929

RESUMO

Magnetic Fe-B, Fe-Ni-B, and Co-B nanoparticles were successfully synthesized and introduced to water to prepare aqueous ferrofluids. The Fe-B, Fe-Ni-B, and Co-B particles are homogeneous amorphous nanoparticles with an average particle size 15 nm. The shape of the amorphous nanoparticles is regular. The Fe-B, Fe-Ni-B, and Co-B amorphous nanoparticles are superparamagnetic. Moreover, the saturation magnetizations of Fe-B and Fe-Ni-B amorphous nanoparticles are 75 emu/g and 51 emu/g. These are approximately 2.8 and 1.9-fold larger than Co-B nanoparticles, respectively. The viscosity of the amorphous ferrofluids has a strong response to external magnetic field. The yield stress increases with increasing magnetic field. The hyperthermia research of amorphous ferrofluids was firstly investigated. The experimental results indicate that the heating temperature of Fe-B ferrofluid and Fe-Ni-B ferrofluid could increase to 42 °C in 750 s and 960 s, respectively, when the output current is 300 A. The temperature could reach 61.6 °C for a Fe-B ferrofluid. The heating efficiencies of the amorphous ferrofluids demonstrate that the Fe-B ferrofluid and Fe-Ni-B ferrofluid may have great potential for biomedical applications.

14.
Biomech Model Mechanobiol ; 17(4): 1083-1092, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29730771

RESUMO

A tumour resection normally involves a large tissue resection and bone replacement. Polyether ether ketone (PEEK) has become a suitable candidate for use in various prostheses owing to its lightness in weight, modulus close to that of natural bone, and good biocompatibility, among other factors. This study proposes a new design method for a rib prosthesis using the centroid trajectory of the natural replaced rib, where the strength can be adjusted by monitoring the cross-sectional area, shape, and properties. A custom-designed rib prosthesis was manufactured using fused deposition modelling (FDM) manufacturing technology, and the mechanical behaviour was found to be close to that of a natural rib. A finite element analysis of the designed rib was carried out under similar loading conditions to those used in mechanical testing. The results indicate that the centroid trajectory derived from a natural rib diaphysis can provide reliable guidance for the design of a rib prosthesis. Such methodology not only offers considerable design freedom in terms of shape and required strength, but also benefits the quality of the surface finishing for samples manufactured using the FDM technique. FDM-printed PEEK rib prostheses have been successfully implanted, and good clinical performances have been achieved.


Assuntos
Cetonas/química , Polietilenoglicóis/química , Impressão Tridimensional , Próteses e Implantes , Desenho de Prótese , Costelas/anatomia & histologia , Adulto , Fenômenos Biomecânicos , Análise de Elementos Finitos , Humanos , Masculino , Costelas/diagnóstico por imagem , Estresse Mecânico , Tomografia Computadorizada por Raios X
15.
Liver Int ; 38(1): 125-135, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28618167

RESUMO

BACKGROUND & AIMS: Neuropilin-1 (NRP-1) activates signalling pathways as multifunctional co-receptors in cancer cells. However, its role and how it is regulated by miRNAs in cholangiocarcinoma (CCA) have not yet been investigated. METHODS: The expression of NRP-1, miR-320 and key molecules involved in cell proliferation, migration and related signalling pathways were detected by immunohistochemistry, immunoblotting and qRT-PCR. Stable transfectants depleted of NRP-1 were generated. The regulatory effect of miR-320 on NRP-1 was evaluated by luciferase reporter assays. Cell proliferation, cell cycle distribution and migration were examined. Xenograft tumour models were established to assess tumourigenesis, tumour growth and lung metastasis. RESULTS: Cholangiocarcinoma tissues expressed higher levels of NRP-1 than adjacent normal biliary tissues, and its expression negatively correlated with miR-320. NRP-1 depletion inhibited cell proliferation and induced cell cycle arrest in the G1/S phase by upregulating p27, and downregulating cyclin E and cyclin-dependent kinase 2; and reduced cell migration by inhibiting the phosphorylation of focal adhesion kinase. NRP-1 depletion suppressed tumourigenesis, tumour growth and lung metastasis by inhibiting cell proliferation and tumour angiogenesis in experimental animals. Depletion of NRP-1 inhibited the activation of VEGF/VEGFR2, EGF/EGFR and HGF/c-Met pathways stimulated by respective ligands. MiR-320 negatively regulated the expression of NRP-1 by binding to the 3'-UTR of NRP-1 promoter, and miR-320 mimics inhibited cell proliferation and migration, and the growth of established tumours in animals by downregulating NRP-1. CONCLUSIONS: The present results indicate that NRP-1 is negatively regulated by miR-320, and both of them may be potentially therapeutic targets for CCA.


Assuntos
Neoplasias dos Ductos Biliares/metabolismo , Movimento Celular , Proliferação de Células , Colangiocarcinoma/metabolismo , Neoplasias Pulmonares/metabolismo , MicroRNAs/metabolismo , Neuropilina-1/metabolismo , Regiões 3' não Traduzidas , Animais , Neoplasias dos Ductos Biliares/genética , Neoplasias dos Ductos Biliares/patologia , Sítios de Ligação , Ciclo Celular , Linhagem Celular Tumoral , Colangiocarcinoma/genética , Colangiocarcinoma/secundário , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/secundário , Masculino , Camundongos Endogâmicos BALB C , Camundongos Nus , MicroRNAs/genética , Neovascularização Patológica , Neuropilina-1/genética , Transdução de Sinais , Carga Tumoral
16.
Nanoscale ; 9(33): 12039-12050, 2017 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-28795729

RESUMO

It is shown that the rotational diffusivity of nanoparticles in polymer solutions spanning the dilute to semi-dilute regimes deviates from the predictions of the Stokes-Einstein (SE) relationship, and that this deviation can be explained by the existence of a polymer depletion layer with the viscosity of the bath solvent. The measurements of the rotational diffusion coefficient of poly(ethylene glycol) (PEG) grafted magnetic nanoparticles in PEG solutions spanning the dilute to semi-dilute regimes and a wide range of polymer molecular weights were obtained from the dynamic magnetic response of the nanoparticles to alternating magnetic fields. Experimental rotational diffusion coefficient values were compared with those predicted by the SE relation using the macroscopic viscosity of the polymer solutions and the hydrodynamic radius of the nanoparticles. Deviations between experimental and SE rotational diffusivity values were observed for nanoparticles in polymer solutions where the radius of gyration of the polymer exceeded the hydrodynamic radius of the particles. A simple model for the rotational hydrodynamic drag on a particle surrounded by a polymer depletion layer was found to describe the experimental rotational diffusivities well, suggesting that the observed phenomenon arises due to the formation of a polymer depletion layer around the nanoparticles.

17.
J Colloid Interface Sci ; 506: 393-402, 2017 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-28750242

RESUMO

The rotational diffusion of polyethylene glycol coated magnetic nanoparticles in serum albumin solutions was investigated in a range spanning 0mgmL-1 to 200mgmL-1. Rotational diffusivities were determined from dynamic magnetic susceptibility measurements, which provide a non-optical means to probe rotation of nanoparticles in small volume samples. Experimental rotational diffusivities were compared to those estimated using the Stokes-Einstein relation and macroscopic measurements of the viscosity of the protein solutions. Excellent agreement was found between experimental measurements and theoretical predictions for serum albumin solutions buffered at physiological pH and for serum albumin solutions at acidic pH prepared using simple acids at physiological ionic strengths. For serum albumin solutions prepared using citrate buffer at acidic pH, we observed a discrepancy between the experimental rotational diffusivity and that predicted from the Stokes-Einstein relation. In contrast, when the pH was adjusted with a simple acid and salt at physiological ionic strength we observed agreement between the experimental rotational diffusivity and that predicted from the Stokes-Einstein relation. Because of the role of citrate ions in causing protein aggregation, we believe these observations suggest that dynamic magnetic susceptibility measurement of the rotational diffusivity of the nanoparticles is sensitive to gelation/crosslinking of proteins.


Assuntos
Nanopartículas de Magnetita/química , Soroalbumina Bovina/química , Ácido Cítrico/química , Reagentes para Ligações Cruzadas/química , Difusão , Concentração de Íons de Hidrogênio , Cinética , Tamanho da Partícula , Polietilenoglicóis/química , Agregados Proteicos , Reologia/métodos , Rotação , Soluções , Propriedades de Superfície , Temperatura , Viscosidade
18.
Chempluschem ; 81(11): 1174-1181, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31964096

RESUMO

Nix Zn1-x Fe2 O4 (x=0, 0.25, 0.5, 0.75, 1) compounds were prepared by a hydrothermal method and subsequent heat treatment. The physical characteristics of the samples were investigated by field-emission SEM, XRD, X-ray photoelectron spectroscopy, and TEM. The electrochemical properties of Nix Zn1-x Fe2 O4 (x=0, 0.25, 0.5, 0.75, 1) as anode materials were tested for lithium-ion batteries. The lithium-storage properties of the electrodes were assessed by cyclic voltammetry and galvanostatic cycling. Among the five samples, Ni0.25 Zn0.75 Fe2 O4 shows good electrochemical performance with a discharge capacity of 1488 mAh g-1 in the initial cycle and 856 mAh g-1 after 100 cycles.

19.
Biomed Tech (Berl) ; 58(2): 205-12, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23412853

RESUMO

Despite the importance of translational medicine in cardiovascular research, rat vascular endothelial function and sympathetic activity assessment remains challenging.This study consisted of two parts: part A examined the consistency of reactive hyperemia-elicited dilatation index(DI) before (DI Original ) and after (DI EEMD ) ensemble empirical mode decomposition (EEMD) using Wistar-Kyoto (WKY)rats (n = 7). Part B compared the endothelial function and heart rate variability of normal WKY rats (group 1, n = 9)with those of spontaneously hypertensive rats (group 2,n = 9) at two time points of development. The SD1/SD2 ratio(SSR) was obtained from Poincaré plot analysis to evaluate sympathetic activities. Using a Bland-Altman plot, part A of the study demonstrated a lower agreement of DI Original than that of DI EEMD . In part B, despite no significant difference in DI EEMD between the two groups at age 10 weeks, DI EEMD was higher in group 1 (2.25 } 0.63 vs. 1.43 } 0.41 for groups 1 and 2, respectively, p = 0.004) at 20 weeks. Although no notable change in SSR existed in group 1 between the twotime points, a significant difference existed in group 2(p < 0.001). In conclusion, using algorithms of Poincaré plot analysis and EEMD, the impact of age and hypertension on rat vascular endothelial function and heart rate variability can be reliably assessed.


Assuntos
Sistema Nervoso Autônomo/fisiopatologia , Diagnóstico por Computador/métodos , Eletrocardiografia/métodos , Endotélio Vascular/fisiopatologia , Hipertensão/diagnóstico , Hipertensão/fisiopatologia , Fotopletismografia/métodos , Algoritmos , Animais , Pressão Sanguínea , Volume Sanguíneo , Frequência Cardíaca , Masculino , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKY , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Processamento de Sinais Assistido por Computador
20.
Artigo em Inglês | MEDLINE | ID: mdl-19164065

RESUMO

At present, many studies indicate that atherosclerosis has high correlation with risk factors of cardiovascular diseases. Furthermore, atherosclerosis usually accompanies with endothelial dysfunction. However, endothelial dysfunction dose not necessarily have situation of atherosclerosis. It means that endothelial dysfunction can be the early change of atherosclerosis. If we can use non-invasive methods to monitor the function of vascular endothelia, it will be very helpful for early assessment of atherosclerosis. It can also detect atherosclerosis earlier then decrease the mortality and mobility of atherosclerosis related diseases, such as coronary artery disease, stroke and chronic renal disease, with appropriate management.


Assuntos
Algoritmos , Endotélio Vascular/fisiologia , Oximetria/instrumentação , Oximetria/métodos , Oxiemoglobinas/análise , Vasodilatação/fisiologia , Animais , Diagnóstico por Computador/instrumentação , Diagnóstico por Computador/métodos , Desenho de Equipamento , Análise de Falha de Equipamento , Ratos , Ratos Endogâmicos WKY , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
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