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1.
Zhonghua Gan Zang Bing Za Zhi ; 31(11): 1182-1186, 2023 Nov 20.
Artículo en Zh | MEDLINE | ID: mdl-38238952

RESUMEN

Objective: To investigate the role of serum hepatitis B virus RNA (HBV RNA) in predicting HBeAg serological conversion in children with chronic hepatitis B. Methods: 175 children aged 1~17 years with chronic hepatitis B who received interferon α (IFNα) for 48 weeks were selected. Patients were divided into HBeAg seroconversion and non-conversion based on whether HBeAg seroconversion occurred at 48 weeks of treatment.T-test and Mann-Whitney U test were used to compare between groups; chisquare test or Fisher exact probability method was used to compare the frequency between groups of classified variables; and Pearson correlation was used to analyze the correlation between indicators. Univariate and multivariate logistic regression analyses were used to identify influencing factors associated with HBeAg serological conversion. The predictive effect of HBV RNA, HBV DNA, and HBsAg on HBeAg serological conversion was compared and analyzed by the receiver operating characteristic curve (ROC). Results: The seroconversion rate of HBeAg at 48 weeks was 36.0% (63/175). The reduction in HBVRNA levels from baseline to the 12th, 24th, 36th, and 48th weeks of antiviral therapy was significantly greater in the HBeAg serological conversion group than that in the non-conversion group, and the difference was statistically significant between the two groups (P < 0.05). Univariate and multivariate regression analyses showed that age and a decline in HBV RNA levels at week 12 were independent predictors of HBeAg serological conversion. The area under the ROC curve (AUROC) of HBV RNA decline at week 12 was 0.677(95% CI∶0.549-0.806, P = 0.012), which was significantly better than the same period of AUROC of HBV DNA (0.657, 95% CI∶0.527-0.788, P = 0.025) and HBsAg (0.660, 95% CI∶0.526-0.795, P = 0.023) decline. HBV RNA levels decreased (>1.385 log10 copies/ml) at week 12, with a positive predictive value of 53.2%, a negative predictive value of 72.2%, a sensitivity of 77.4%, and a specificity of 57.9% for HBeAg seroconversion. Conclusion: HBV RNA level lowering during the 12th week of antiviral therapy can serve as an early predictor marker for HBeAg serological conversion in children with chronic hepatitis B.


Asunto(s)
Virus de la Hepatitis B , Hepatitis B Crónica , Niño , Humanos , Antígenos e de la Hepatitis B , Antígenos de Superficie de la Hepatitis B , Antivirales/uso terapéutico , ADN Viral , ARN Viral , Resultado del Tratamiento
2.
Phys Chem Chem Phys ; 24(36): 22000-22006, 2022 Sep 21.
Artículo en Inglés | MEDLINE | ID: mdl-36069469

RESUMEN

Stable configurations with excellent optical adsorption are crucial for photovoltaics or photocatalysis. Two-dimensional materials with intrinsic electric fields have been proposed as suitable for electric and optical devices. Here, we have performed DFT calculations on the electronic and optical properties of a bilayer Sb/InS van der Waals heterostructure, which consists of Sb and InS monolayers, by studying the band structures, charge density difference and distribution. Interestingly, the Sb/InS bilayer exhibits typical type-II band alignment character with a direct energy gap of 0.44 eV, and the electrons and holes are separated on different surfaces. Furthermore, applying an external E-field and biaxial strain is proved to be an effective way to modify the energy gap, the same as the electronic and optical properties. These theoretical predictions pave the way for high performance electronic and optical devices based on new two-dimensional van der Waals structures.

3.
Public Health ; 209: 67-72, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35839623

RESUMEN

OBJECTIVE: To investigate the pharmacist's knowledge about rational use of antimicrobials in Shanxi of China, so as to find out the problems and provide support for the management of antimicrobials. METHODS: A questionnaire survey was conducted, which included the basic information of the respondents, the basic knowledge about antimicrobial management and the related knowledge about antimicrobial drugs. SPSS 25.0 was used for statistical analysis. RESULTS: A total of 462 pharmacists were investigated. The average score of the knowledge related to rational use of antimicrobials was 10.49 ± 4.05. It showed that the hospital type, grade, pharmacist's education, professional title and years of experience had effect on the pharmacist's knowledge level about antimicrobial drugs (P < 0.05). Multivariable logistic regression analysis showed that hospital grade and pharmacist's education were the main influencing factors (P < 0.05). CONCLUSION: Pharmacists have insufficient knowledge about the rational use of antibacterial drugs. It is essential to strengthen the training in management regulations and application of antibacterial drugs.


Asunto(s)
Antiinfecciosos , Farmacéuticos , Antibacterianos/uso terapéutico , Antiinfecciosos/uso terapéutico , China , Humanos , Encuestas y Cuestionarios
4.
Beijing Da Xue Xue Bao Yi Xue Ban ; 52(2): 302-307, 2020 Apr 18.
Artículo en Zh | MEDLINE | ID: mdl-32306015

RESUMEN

OBJECTIVE: To analyze how governments, hospitals and information technology(IT) companies use Internet technology to provide online health services during the early stage of corona virus disease 2019 (COVID-19) epidemic in January 2020 in China, and then provide suggestions and coping strategies for the later stage and post-epidemic time. METHODS: We searched for information on ehealth services related to the outbreak of COVID-19 in China. The sources of information were mainstream search engines such as Baidu and the popular interactive social platforms such as Webchat. The keywords were "Internet+pneumonia", "Internet clinic", "pneumonia online clinic" and so on. The time of information was from January 20 to February 3, 2020. The key information was extracted and encoded by two persons back-to-back. The coding information included: name of organization provider, launching time, location of provider, service items, user, health workers engaging in the service, and so on. The coded information was entered and analyzed with SPSS 24.0 and Excel. RESULTS: There were totally 57 projects launched by local governments, hospitals and IT companies. Most of them were launched from January 24th to 27th, the hospital and government projects services regionally, especially in eastern provinces. In this study, 90.48% of the enterprises and 100.00% of the hospitals had online fever clinic and consultation services for COVID-19, 66.67% of the enterprises and 37.04% of the hospitals serviced derivative health problems. Only a few projects provided tele-medical consultation. There were individual projects that provided online health management for home quarantine people. Physicians were the main force of various projects. In some hospital projects, there were also nurses, pharmacists and professional technicians to provide featured consultation. CONCLUSION: Ehealth is useful and helpful for the health care system to rapidly cope with health demand during instantaneous and post epidemic time. Regional distribution of ehealth is unbalanced. There are institutional and technical feasibilities for the emergency application of Internet technology. However, community health centers seldom provide ehealth or connect with tertiary hospitals with Internet. Therefore, all kinds of providers within healthcare system should promote emergence ehealth. Tele-medical diagnosis and referral should be developed by local governments during COVID-19. The application of "Internet+medical treatment" in community medical institutions and synergy among various institutions should be promoted.


Asunto(s)
Betacoronavirus , Infecciones por Coronavirus , Pandemias , Neumonía Viral , Telemedicina , COVID-19 , China , Humanos , SARS-CoV-2
5.
Zhonghua Yi Xue Za Zhi ; 99(35): 2777-2780, 2019 Sep 17.
Artículo en Zh | MEDLINE | ID: mdl-31550802

RESUMEN

Objective: To investigate the effect of intraoperative warming on the postoperative relaxation recovery of cisatracurium in patients undergoing gastrointestinal surgery. Methods: Sixty ASA Ⅰ-Ⅱ patients, aged 20 to 60, undergoing elective gastrointestinal surgery in Cancer Hospital Chinese Academy of Medical Sciences from October, 2016 to March, 2019 were selected and they were randomly divided into two groups (n=30), N group and H group by random number table. N group was non-heat preserving group, and H group was heat preserving group. Tracheal intubation was induced by general anesthesia with cisatracurium 0.15 mg/kg, and the nasopharyngeal temperature were continuously monitored and recorded. Cisatracurium were infused 1-3 µg·kg(-1)·min(-1) by venous pump during operation with T1 at 1%-10% and stopped infusion 30 minutes before the end of surgery. The time when T1 recovered from 25% to 75%(muscle relaxation recovery index), and the time of T1 recovered to 25% to TOF ratios (TOFR, the ratio of the fourth muscle twitch height to T1 in TOF) recovery to 90% (full recovery time), cumulative drug use and surgery time were recorded. Results: There was no significant difference between the two groups in the cumulative drug dosage and operation time (P>0.05).The body temperature N group (35.7±0.2) ℃ was significantly lower than the H group (36.2±0.1) ℃ (t=13.940, P<0.01). The recovery index of N group (16.5±1.8) min was significantlyhigher than H group (10.5±2.1) min (t=12.094, P<0.01) and complete recovery time in N group (26.9±4.1) min was obviously longer than those in H group (15.0±2.9) (t=13.082, P<0.01). Conclusions: Patients with open gastrointestinal surgery are prone to hypothermia during surgery and heat protection is helpful to muscle relaxation recovery of cisatracurium.


Asunto(s)
Atracurio/análogos & derivados , Temperatura Corporal , Procedimientos Quirúrgicos del Sistema Digestivo , Hipotermia/prevención & control , Relajación Muscular , Adulto , Anestesia General , Atracurio/administración & dosificación , Humanos , Cuidados Intraoperatorios , Persona de Mediana Edad , Adulto Joven
6.
Zhonghua Gan Zang Bing Za Zhi ; 27(3): 192-197, 2019 Mar 20.
Artículo en Zh | MEDLINE | ID: mdl-30929335

RESUMEN

Objective: To explore chromobox protein homolog 2 (CBX2) expressions in relation to clinical features of patients and elucidate its role in the progression of hepatocellular carcinoma. Methods: Using the Cancer Genome Atlas (TCGA) database, R language was used to analyze the distribution of differentially expressed mRNA in hepatocellular carcinoma. The different expression of CBX2 in HCC and adjacent tissues and its relationship with survival and clinical characteristics of patients were further analyzed. The expression of CBX2 in liver tissues, liver cancer tissue, and L02, HepG2 and SMMC-7721 cell lines was detected by real time-PCR and western blot. The expression of CBX2 was interfered by siRNA in hepatoma cell line. MTT, colony formation, transwell assays, and flow cytometry were used to identify the proliferation, apoptosis, invasion and clone-formation ability of HepG2 and SMMC-7721 cells after CBX2 down-regulation. According to the different data, t-test, ANOVA, chi-square test, and COX regression model were used for statistical analysis. Survival curve was plotted through Kaplan-Meier method. Results: TCGA public database analysis showed that the expression of CBX2 mRNA in hepatocellular carcinoma tissues (7.296 ± 1.6115) was significantly higher than normal liver tissues (4.706 ± 0.940) (P = 0.000). In addition, the overall survival time of patients with low CBX2 mRNA expression was significantly longer than that of patients with high CBX2 mRNA expression [(5.971 ± 0.411) years vs. (4.650 ± 0.503) years, P = 0.001]. The expression level of CBX2 mRNA was correlated with the pathological TNM stage (P = 0.025) and differentiation degree (P < 0.001) of liver cancer. COX regression analysis showed that CBX2 mRNA expression was an independent predictor of patient survival (P = 0.013). siRNA was transfected and compared with the blank control group. The transgenic ability of HepG2 and SMMC-77221 cells decreased significantly at 72h (P < 0.05) and 96h (P < 0.05), and the apoptosis rate (11.430% ± 0.215%) was higher than blank control group (6.6 00% ± 0.170%) (P = 0.003). The number of invasive cells ((both P < 0.05) and relative colony forming cells ((both P < 0.001) were significantly decreased. In 20 cases of tissue samples, the expression of CBX2 protein (relative expression level 3.020 ± 0.269) in liver cancer was higher than that in adjacent tissues (relative expression level 0.886±0.065) (P < 0.001). The overall survival time of patients with low CBX2 expression in liver cancer was longer than that of patients with high expression [(3.670 + 0.576) years vs. (0.834 + 0.153) years, P = 0.004]. Conclusion: An evident high expression of CBX2 is an independent poor prognostic factor in hepatoma. Down-regulation of CBX2 expression can inhibit the progression of liver cancer. Therefore, CBX2 may be a prognostic biomarker and a new target for HCC treatment.


Asunto(s)
Carcinoma Hepatocelular , Neoplasias Hepáticas , Adulto , Proliferación Celular , Regulación hacia Abajo , Regulación Neoplásica de la Expresión Génica , Células Hep G2 , Humanos
7.
Phys Chem Chem Phys ; 19(11): 7864-7870, 2017 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-28262871

RESUMEN

Transition metal (TM) nanostructures, such as one dimensional (1D) nanowires with/without substrates, usually possess drastically different properties from their bulk counterparts, due to their distinct stacking and electronic confinement. Correspondingly, it is of great importance to establish the dominant driving force in forming 1D single-metal-atom-wires (SMAWs). Here, with first-principles calculations, taking the black phosphorene (BP) monolayer as a prototype 2D substrate, we investigate the energetic and kinetic properties of all the 5d-TM atoms on the 2D substrate to reveal the mechanism of formation of SMAWs. In contrast to other 5d- and 4d-TMs, noble metal elements Pd and Pt are found to prefer to grow along the trough in an atom-by-atom manner, self-assembling into SMAWs with a significant magic growth behavior. This is due to distinct binding energies and diffusion barriers along the trough, i.e., zig-zag direction, as compared to other directions of the BP. The present findings are valuable in the fabrication and modulation of 1D nanostructures which can be anticipated to possess desirable functionalities for potential applications such as in nanocatalysis, nanosensors, and related areas.

8.
J Chem Phys ; 143(17): 174302, 2015 Nov 07.
Artículo en Inglés | MEDLINE | ID: mdl-26547165

RESUMEN

Nanoclusters usually display exotic physical and chemical properties due to their intriguing geometric structures in contrast to their bulk counterparts. By means of first-principles calculations within density functional theory, we find that heavy noble metal PtN nanoclusters around the size N = 55 begin to prefer an open configuration, rather than previously reported close-packed icosahedron or core-shell structures. Particularly, for PtN, the widely supposed icosahedronal magic cluster is changed to a three-atomic-layered structure with D6h symmetry, which can be well addressed by our recently established generalized Wulff construction principle (GWCP). However, the magic number of PtN clusters around 55 is shifted to a new odd number of 57. The high symmetric three-layered Pt57 motif is mainly stabilized by the enhanced covalent bonding contributed by both spin-orbital coupling effect and the open d orbital (5d(9)6s(1)) of Pt, which result in a delicate balance between the enhanced Pt-Pt covalent bonding of the interlayers and negligible d dangling bonds on the cluster edges. These findings about PtN clusters are also applicable to IrN clusters, but qualitatively different from their earlier neighboring element Os and their later neighboring element Au. The magic numbers for Os and Au are even, being 56 and 58, respectively. The findings of the new odd magic number 57 are the important supplementary of the recently established GWCP.

9.
Genet Mol Res ; 14(3): 9675-82, 2015 Aug 14.
Artículo en Inglés | MEDLINE | ID: mdl-26345900

RESUMEN

FKBP38 (also known as FKBP8) is a unique member of the FK506-binding protein (FKBP) family, and its role is controversial because it acts as an upstream regulator of the mTOR signaling pathway, which controls cell growth, proliferation, and differentiation. This study aimed to explore the role of FKBP38 in the activation of mTOR signaling in Cashmere goat (Capra hircus) fetal fibroblasts. To construct a Cashmere goat FKBP38 siRNA eukaryotic expression vector that targets FKBP38 mRNA, we designed shRNA based on the gene sequence deposited in GenBank (accession No. JF714970) and synthesized a DNA fragment encoding the shRNA. The DNA fragment was inserted into the pRNAT-U6.1/Neo vector to construct an expression vector of shRNA, which was labeled pRNAT-FKBP38-shRNA. The recombinant plasmid was used to transfect Cashmere goat fetal fibroblasts (GFb) using lipofectamine™2000. We found that cells were successfully transfected with pRNAT-U6.1/Neo-FKBP38-shRNA. Green fluorescence could be observed in cells following 48-h transfection. Proteins were then isolated from GFbs transfected with pRNAT-FKBP38-shRNA and from control cells, and protein expression was analyzed by western blot. Expression of FKBP38 decreased and mTOR signaling was activated, which induced the phosphorylation of mTOR, S6, and 4EBP1. Thus, FKBP38 gene-silencing activates mTOR signaling in goat cells.


Asunto(s)
Fibroblastos/metabolismo , Silenciador del Gen , Cabras/genética , Cabras/metabolismo , ARN Interferente Pequeño/genética , Transducción de Señal , Serina-Treonina Quinasas TOR/metabolismo , Proteínas de Unión a Tacrolimus/genética , Animales , Secuencia de Bases , Células Cultivadas , Expresión Génica , Orden Génico , Vectores Genéticos/genética , Fosforilación , ARN Mensajero/química , ARN Mensajero/genética , ARN Interferente Pequeño/química , Proteínas Quinasas S6 Ribosómicas/metabolismo , Proteínas de Unión a Tacrolimus/química , Transfección
10.
Genet Mol Res ; 14(3): 11154-61, 2015 Sep 22.
Artículo en Inglés | MEDLINE | ID: mdl-26400346

RESUMEN

Fibroblast growth factor 5 (FGF5) is a secreted signaling protein that belongs to the FGF family, and was found to be associated with hair growth in humans and other animals. The Inner Mongolia Cashmere goat (Capra hircus) is a goat breed that provides superior cashmere; this breed was formed by spontaneous mutation in China. Here, we report the cloning, molecular characterization, and expression pattern of the Cashmere goat FGF5. The cloned FGF5 cDNA was 813 base pairs (KM596772), including an open reading frame encoding a 270-amino-acid polypeptide. The nucleotide sequence shared 99% homology with Ovis aries FGF5 (NM_001246263.1). Bioinformatic analysis revealed that FGF5 contained a signal peptide, an FGF domain, and a heparin-binding growth factor/FGF family signature. There was 1 cAMP- and cGMP-dependent protein kinase phosphorylation site, 11 protein kinase C phosphorylation sites, 4 casein kinase II phosphorylation sites, 1 amidation site, 1 N-glycosylation site, and 1 tyrosine kinase phosphorylation site in FGF5. Real-time polymerase chain reaction showed that FGF5 mRNA levels were higher in testis than in the pancreas and liver. These data suggest that FGF5 may play a crucial role in Cashmere goat hair growth.


Asunto(s)
Factor 5 de Crecimiento de Fibroblastos/genética , Expresión Génica , Cabras/metabolismo , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Células Cultivadas , Clonación Molecular , Factor 5 de Crecimiento de Fibroblastos/química , Factor 5 de Crecimiento de Fibroblastos/metabolismo , Cabras/genética , Masculino , Modelos Moleculares , Datos de Secuencia Molecular , Especificidad de Órganos , Filogenia , ARN Mensajero , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido , Testículo/metabolismo
11.
Br J Cancer ; 110(3): 733-40, 2014 Feb 04.
Artículo en Inglés | MEDLINE | ID: mdl-24495874

RESUMEN

BACKGROUND: Cytokines are tightly linked to the carcinogenesis, development and prognosis of hepatocellular carcinoma (HCC). We determined the prognostic value of 39 circulating cytokines in HCC patients after radical resection and then developed a novel cytokine-based prognostic classifier (CBPC) for the prediction of patient prognosis. METHODS: A total of 179 patients were divided into two cohorts based on the date of radical resection. Thirty-nine cytokines were simultaneously analysed in patient serum samples using multiplex bead-based Luminex technology. Support vector machine-based methods and Cox proportional hazard models were used to develop a CBPC from the training cohort, which was then validated in the validation cohort. RESULTS: Among seven cytokines significantly correlating with the disease-free survival (DFS) in the training cohort, six of them were validated to be significant prognostic factors to predict DFS and overall survival (OS) in the validation cohort, namely fibroblast growth factor 2 (FGF-2), growth-regulated oncogene (GRO), interleukin 8 (IL-8), interferon gamma-induced protein 10 (IP-10), vascular endothelial growth factor (VEGF), and interferon alpha-2 (IFN-α2). By integrating six cytokines and three clinical characteristics, we developed a CBPC to predict the recurrence and 3-year OS of HCC patients (sensitivity, 0.648; specificity, 0.918). In the validation cohort, the CBPC were confirmed to have significant predictive power for predicting tumour recurrence and OS (sensitivity, 0.585; specificity, 0.857). Interestingly, IFN-α2 was the only cytokine being independent prognostic factor in both patient cohorts. CONCLUSION: Our study verifies the presence of specific cytokine-phenotype associations with patient prognosis in HCC. The CBPC developed include multiple circulating cytokines and may serve as a novel screening approach for identifying HCC patients with a high risk of post-resection recurrence and shorter OS. These individuals may also be suitable for cytokine-targeted therapies.


Asunto(s)
Carcinoma Hepatocelular/diagnóstico , Citocinas/biosíntesis , Neoplasias Hepáticas/diagnóstico , Recurrencia Local de Neoplasia/diagnóstico , Adulto , Anciano , Carcinoma Hepatocelular/patología , Estudios de Cohortes , Supervivencia sin Enfermedad , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Neoplasias Hepáticas/patología , Masculino , Persona de Mediana Edad , Recurrencia Local de Neoplasia/genética , Pronóstico , Modelos de Riesgos Proporcionales
12.
Stem Cell Res Ther ; 15(1): 113, 2024 Apr 23.
Artículo en Inglés | MEDLINE | ID: mdl-38650025

RESUMEN

BACKGROUND: Oral submucous fibrosis (OSF) is a precancerous lesion characterized by fibrous tissue deposition, the incidence of which correlates positively with the frequency of betel nut chewing. Prolonged betel nut chewing can damage the integrity of the oral mucosal epithelium, leading to chronic inflammation and local immunological derangement. However, currently, the underlying cellular events driving fibrogenesis and dysfunction are incompletely understood, such that OSF has few treatment options with limited therapeutic effectiveness. Dental pulp stem cells (DPSCs) have been recognized for their anti-inflammatory and anti-fibrosis capabilities, making them promising candidates to treat a range of immune, inflammatory, and fibrotic diseases. However, the application of DPSCs in OSF is inconclusive. Therefore, this study aimed to explore the pathogenic mechanism of OSF and, based on this, to explore new treatment options. METHODS: A human cell atlas of oral mucosal tissues was compiled using single-cell RNA sequencing to delve into the underlying mechanisms. Epithelial cells were reclustered to observe the heterogeneity of OSF epithelial cells and their communication with immune cells. The results were validated in vitro, in clinicopathological sections, and in animal models. In vivo, the therapeutic effect and mechanism of DPSCs were characterized by histological staining, immunohistochemical staining, scanning electron microscopy, and atomic force microscopy. RESULTS: A unique epithelial cell population, Epi1.2, with proinflammatory and profibrotic functions, was predominantly found in OSF. Epi1.2 cells also induced the fibrotic process in fibroblasts by interacting with T cells through receptor-ligand crosstalk between macrophage migration inhibitory factor (MIF)-CD74 and C-X-C motif chemokine receptor 4 (CXCR4). Furthermore, we developed OSF animal models and simulated the clinical local injection process in the rat buccal mucosa using DPSCs to assess their therapeutic impact and mechanism. In the OSF rat model, DPSCs demonstrated superior therapeutic effects compared with the positive control (glucocorticoids), including reducing collagen deposition and promoting blood vessel regeneration. DPSCs mediated immune homeostasis primarily by regulating the numbers of KRT19 + MIF + epithelial cells and via epithelial-stromal crosstalk. CONCLUSIONS: Given the current ambiguity surrounding the cause of OSF and the limited treatment options available, our study reveals that epithelial cells and their crosstalk with T cells play an important role in the mechanism of OSF and suggests the therapeutic promise of DPSCs.


Asunto(s)
Células Epiteliales , Fibrosis de la Submucosa Bucal , Humanos , Fibrosis de la Submucosa Bucal/patología , Fibrosis de la Submucosa Bucal/metabolismo , Animales , Células Epiteliales/metabolismo , Linfocitos T/metabolismo , Linfocitos T/inmunología , Ratas , Células Madre/metabolismo , Células Madre/citología , Masculino , Mucosa Bucal/patología , Mucosa Bucal/metabolismo , Comunicación Celular
13.
Phys Chem Chem Phys ; 15(6): 1831-6, 2013 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-23247069

RESUMEN

First-principles calculations using density functional theory (DFT) have been performed on Sn(n) clusters up to 561 atoms. The results show that thread-like structures based on the unit of Sn(15) are favored for n up to 60, and then a plate-like Sn(90) unit is preferred. The unique structures are explained by the strong covalent bonding character of Sn(15) units. Due to the weak binding forms among layers, plate-like stacked structures are less preferred than octahedral (O(h)) structures with n = 231. Besides, perfect icosahedral (I(h)) structures are always more favorable than O(h) isomers. The structural deviation of larger tin clusters from that of typical metal clusters may originate from the disparity in α/ß tin bulk and more compact fcc bulk phases. Compared with the previous studies, we conclude that the weaker the bulk metallic character, the larger the nonmetal-metal transition size. After considering the van der Waals density functional (vdW-DF), we found that the average bond length of tin clusters becomes larger and more compact structures will be further stabilized. Our studies may provide some insight for experiments to assemble tin nanowires.

14.
Zhonghua Fu Chan Ke Za Zhi ; 53(11): 740-741, 2018 Nov 25.
Artículo en Zh | MEDLINE | ID: mdl-30453419
15.
Phys Chem Chem Phys ; 13(17): 7649-59, 2011 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-21336360

RESUMEN

Electronic structure calculations have been used to determine and compare the thermodynamics of H(2) release from ammonia borane (NH(3)BH(3)), lithium amidoborane (LiNH(2)BH(3)), and sodium amidoborane (NaNH(2)BH(3)). Using two types of exchange correlation functional we show that in the gas-phase the metal amidoboranes have much higher energies of complexation than ammonia borane, meaning that for the former compounds the B-N bond does not break upon dehydrogenation. Thermodynamically however, both the binding energy for H(2) release and the activation energy for dehydrogenation are much lower for NH(3)BH(3) than for the metal amidoboranes, in contrast to experimental results. We reconcile this by also investigating the effects of dimer complexation (2×NH(3)BH(3), 2×LiNH(2)BH(3)) on the dehydrogenation properties. As previously described in the literature the minimum energy pathway for H(2) release from the 2×NH(3)BH(3) complex involves the formation of a diammoniate of diborane complex ([BH(4)](-)[NH(3)BH(2)NH(3)](+)). A new mechanism is found for dehydrogenation from the 2×LiNH(2)BH(3) dimer that involves the formation of an analogous dibroane complex ([BH(4)](-)[LiNH(2)BH(2)LiNH(2)](+)), intriguingly it is lower in energy than the original dimer (by 0.13 eV at ambient temperatures). Additionally, this pathway allows almost thermoneutral release of H(2) from the lithium amidoboranes at room temperature, and has an activation barrier that is lower in energy than for ammonia borane, in contrast to other theoretical research. The transition state for single and dimer lithium amidoborane demonstrates that the light metal atom plays a significant role in acting as a carrier for hydrogen transport during the dehydrogenation process via the formation of a Li-H complex. We posit that it is this mechanism which is responsible, in condensed molecular systems, for the improved dehydrogenation thermodynamics of metal amidoboranes.

16.
J Mech Behav Biomed Mater ; 112: 103986, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-32823001

RESUMEN

OBJECTIVES: Purpose of the present study was to explore the improvement of wear performance for a nano fluorapatite veneering porcelain by ion-exchange. METHODS: Bar and disk specimens were prepared by IPS e.max Ceram as the nano fluorapatite veneering porcelain. Ion-exchange was performed in a melted KNO3 bath at two temperatures for different time-periods. After the ion-exchange, the bars were tested for flexural strength, surface Vickers hardness and HIF toughness, the disks were tested for wear performance paired with zirconia antagonist using a pin-on-disk tribometer with 10 N for 70✕104 wear cycles in artificial saliva. Wear analysis of the porcelain and zirconia was performed with a 3D profilometer. The microstructure and worn surface morphology were examined with scanning electron microscopy. One-way analysis of variance and Tukey's post-hoc pairwise comparison were used to analyse the wear data. RESULTS: The nano fluorapatite veneering porcelain before ion-exchange presented strong time-dependent wear behavior. Furthermore, wear rate of the original porcelain exhibited a very large standard deviation in the running-in wear stage, which was correlated with highly inhomogeneous distribution of the characteristic fluorapatite crystals in the microstructure. After ion-exchange at 350 °C and 380 °C, especially after the processing at 350 °C for 128 h, the wear rates of both running-in and steady wear stages could be significantly decreased. More importantly, the standard deviation of wear rate in the running-in wear stage could be remarkably reduced after the treatment. The improved reliability of wear performance was attributed to the strengthening and toughening effects of the ion-exchange processing. CONCLUSION: For the fluorapatite veneering porcelain, the ion-exchange protocol to obtain an ion-exchange layer with less stress relaxation and a considerable depth could strengthen and toughen the porcelain; as a result, the reliability of wear performance could be remarkably improved.


Asunto(s)
Cerámica , Porcelana Dental , Apatitas , Análisis del Estrés Dental , Coronas con Frente Estético , Ensayo de Materiales , Reproducibilidad de los Resultados , Propiedades de Superficie , Circonio
17.
Eur Rev Med Pharmacol Sci ; 24(23): 11986, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-33336713

RESUMEN

The article "Suppression of microRNA-101 attenuates hypoxia-induced myocardial H9c2 cell injury by targeting DIMT1-Sp1/survivin pathway, by Z.-X. Guo, F.-Z. Zhou, W. Song, L.-L. Yu, W.-J. Yan, L.-H. Yin, H. Sang, H.-Y. Zhang, published in Eur Rev Med Pharmacol Sci 2018; 22 (20): 6965-6976-DOI: 10.26355/eurrev_201810_16167-PMID: 30402863" has been withdrawn from the authors due to some inaccuracies. The Publisher apologizes for any inconvenience this may cause. https://www.europeanreview.org/article/16167.

18.
J Chem Phys ; 131(18): 184301, 2009 Nov 14.
Artículo en Inglés | MEDLINE | ID: mdl-19916598

RESUMEN

First-principles calculations are used to systematically investigate the geometric and electronic structures of both pure TM(n) (n=2-4) and Ag-modulated AgTM(n-1) (n=2-4; 3d-transition metal (TM): from Sc to Cu; 4d-TM: from Y to Ag elements) clusters. Some new ground state structures are found for the pure TM(n) clusters, such as a low symmetry configuration for Cr(3), which is found to be about 0.20 eV more stable than the previously reported C(2v) symmetry. In the most cases, Ag-doping can significantly elongate the bond lengths of the clusters and induce geometric distortions of the small clusters from the high dimensional to the low dimensional configurations. Importantly, introduction of Ag significantly changes the electronic structures of the small clusters and modulates the density of states in the proximity of the Fermi levels, which also varies with the size and the type of the cluster. The results contribute to future design of effective bimetallic alloy Ag/TM catalysts.

19.
J Nanosci Nanotechnol ; 9(2): 1214-7, 2009 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19441490

RESUMEN

Ti-24Nd-4Zr-7.9Sn alloy with low elastic modulus and high strength is a great candidate for artificial biomaterials used in orthopedic and dental implants. In order to improve biocompatibility, a biomimetic process was employed to deposit a bone-like apatite nanocrystal coating on alloy. Analysis of the coatings showed that a net-like Na2TiO3 layer with about 100 nm in size was formed on Ti-24Nd-4Zr-7.9Sn treated by NaOH. Consequently, a carbonated apatite nanocrystal coating, namely bone-like apatite, was biomimetically deposited on Na2TiO3 layer, which has similar mineral composition to that of natural bone. The growth mechanism of bone-like layer is also discussed.

20.
Eur Rev Med Pharmacol Sci ; 22(20): 6965-6976, 2018 10.
Artículo en Inglés | MEDLINE | ID: mdl-30402863

RESUMEN

OBJECTIVE: MicroRNAs (miRNAs) are small single-stranded RNAs in eukaryotic cells, which play important regulatory roles in the pathogenesis of various diseases. We aimed to investigate the effects of miRNA-101 (miR-101) on hypoxia-induced myocardial infarction (MI) cell injury model (myocardial H9c2 cell injury model). The possible target gene of miR-101 was also analyzed. MATERIALS AND METHODS: H9c2 cells were exposed to hypoxia treatment. Cell viability, migration, invasion, apoptosis and the expression of miR-101 were detected using CCK-8 assay, transwell assay, flow cytometer analysis, Western blotting and qRT-PCR, respectively. Then, the effects of miR-101 overexpression or suppression on the cell injury induced by hypoxia were assessed. Dual luciferase reporter assay was used to analyze the possible target gene of miR-101. Finally, the effects of dimethyladenosine transferase 1 homolog (DIMT1), the possible target gene of miR-101, on H9c2 cell injury were investigated. RESULTS: Hypoxia significantly induced H9c2 cell injury. miR-101 was up-regulated after hypoxia induction. Hypoxia-induced cell injury was significantly reversed by miR-101 suppression and exacerbated by miR-101 overexpression. DIMT1 was a direct target gene of miR-101. Knockdown of DIMT1 markedly inhibited the protective effects of miR-101 suppression on hypoxia-induced cell injury by suppressing specific protein 1 (Sp1)/Survivin pathway. CONCLUSIONS: We verified the critical roles of miR-101 in regulating myocardial cell injury induced by hypoxia. DIMT1-mediated the Sp1/Survivin pathway was also involved in this process. Our findings replenished the understanding of the regulatory roles of miRNAs in hypoxia-induced MI cell injury and provided new molecular target for therapy and diagnosis of MI.


Asunto(s)
Hipoxia de la Célula/genética , MicroARNs/genética , Factor de Transcripción Sp1/metabolismo , Survivin/metabolismo , Animales , Apoptosis/genética , Línea Celular , Supervivencia Celular/genética , Hipoxia/metabolismo , Miocitos Cardíacos/metabolismo , Ratas , Transducción de Señal , Transferasas/genética , Regulación hacia Arriba
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