4,445 research outputs found

    Recent progress of mesoporous silica materials

    Get PDF
    Since the synthesis of novel mesoporous silica materials in 1992, the materials have become a great demand in many research fields. The authors reviewed the synthesis of mesoporous silica materials and their classification, their formation mechanism, as well as the aspects of controlling porosity and recent progresses of their applications. The mesoporous silica materials may be found great utility in catalysis and nano-technology etc

    Effect of Ti-doping on the framework Structure of Mesoporous silica

    Get PDF
    The Ti-doped mesoporous silica MCM-41 materials were synthesized under basic condition at room temperature. The characteristics of samples were investigated by using XRD, HREM, IR, and N-2 adsorption techniques. The results show that Ti ions can get into the Si frame work and lead to the vibration of Si-O-Ti bond, with the increase of Ti ion addition, the mesoporous silica framework structure can be disordered and finally deteriorated

    Synthesis of ordered mesoporous aluminosilicate under a low surfactant/silica molar ratio condition

    Get PDF
    Ordered mesoporous aluminosilicate materials with atomic Si/Al ratios of 16 similar to 64 were synthesized at a very low molar ratio of surfactant/silica (0.12) by using aluminium chloride hexahydrate and TEOS as the sources of aluminium and silicon. The resulting materials were characterized by XRD, TEM, FTIR and nitrogen sorption. As the NaOH/Si molar ratio increases from 0.2 to 0.6, the products obtained change from hexagonal MCM-41 to cubic MCM-48. The quality of the product rapidly deteriorates as the aluminium content of the solid increases beyond a certain limit. XRD shows that the substitution of the silicon by the large aluminium atoms leads to the expansion of the unit cell

    Study on the synthesis and mechanism of mesoporous silica with hexastyle structure

    Get PDF
    The mesoporous silica MCM-41 materials with hexastyle structure were synthesized under strongly acidic condition. The characteristics of samples were investigated by using XRD, N-2 adsorption, HREM, and SEM techniques. The results show that MCM-41 powder with hexastyle structure, which is wormlike in micrometer-scale, consists of thousands of mesoporous channels in nano-scale. The morphogenesis of hexastyle mesoporous silica is due to the accretion of surfactant micella combined with silica oligmers in the low concentration of TEOS

    Impact of metabolic comorbidity on the association between body mass index and heatlh-related quality of life: a Scotland-wide cross-sectional study of 5,608 participants

    Get PDF
    <p/>Background: The prevalence of obesity is rising in Scotland and globally. Overall, obesity is associated with increased morbidity, mortality and reduced health-related quality of life. Studies suggest that "healthy obesity" (obesity without metabolic comorbidity) may not be associated with morbidity or mortality. Its impact on health-related quality of life is unknown. <p/>Methods: We extracted data from the Scottish Health Survey on self-reported health-related quality of life, body mass index (BMI), demographic information and comorbidity. SF-12 responses were converted into an overall health utility score. Linear regression analyses were used to explore the association between BMI and health utility, stratified by the presence or absence of metabolic comorbidity (diabetes, hypertension, hypercholesterolemia or cardiovascular disease), and adjusted for potential confounders (age, sex and deprivation quintile). <p/>Results: Of the 5,608 individuals, 3,744 (66.8%) were either overweight or obese and 921 (16.4%) had metabolic comorbidity. There was an inverted U-shaped relationship whereby health utility was highest among overweight individuals and fell with increasing BMI. There was a significant interaction with metabolic comorbidity (p = 0.007). Individuals with metabolic comorbidty had lower utility scores and a steeper decline in utility with increasing BMI (morbidly obese, adjusted coefficient: -0.064, 95% CI -0.115, -0.012, p = 0.015 for metabolic comorbidity versus -0.042, 95% CI -0.067, -0.018, p = 0.001 for no metabolic comorbidity). <p/>Conclusions: The adverse impact of obesity on health-related quality of life is greater among individuals with metabolic comorbidity. However, increased BMI is associated with reduced health-related quality of life even in the absence of metabolic comorbidity, casting doubt on the notion of "healthy obesity"

    Anti-epileptic effect of Ganoderma lucidum polysaccharides by inhibition of intracellular calcium accumulation and stimulation of expression of CaMKII a in epileptic hippocampal neurons

    Get PDF
    Purpose: To investigate the mechanism of the anti-epileptic effect of Ganoderma lucidum polysaccharides (GLP), the changes of intracellular calcium and CaMK II a expression in a model of epileptic neurons were investigated. Method: Primary hippocampal neurons were divided into: 1) Control group, neurons were cultured with Neurobasal medium, for 3 hours; 2) Model group I: neurons were incubated with Mg2+ free medium for 3 hours; 3) Model group II: neurons were incubated with Mg2+ free medium for 3 hours then cultured with the normal medium for a further 3 hours; 4) GLP group I: neurons were incubated with Mg2+ free medium containing GLP (0.375 mg/ml) for 3 hours; 5) GLP group II: neurons were incubated with Mg2+ free medium for 3 hours then cultured with a normal culture medium containing GLP for a further 3 hours. The CaMK II a protein expression was assessed by Western-blot. Ca2+ turnover in neurons was assessed using Fluo-3/AM which was added into the replacement medium and Ca2+ turnover was observed under a laser scanning confocal microscope. Results: The CaMK II a expression in the model groups was less than in the control groups, however, in the GLP groups, it was higher than that observed in the model group. Ca2+ fluorescence intensity in GLP group I was significantly lower than that in model group I after 30 seconds, while in GLP group II, it was reduced significantly compared to model group II after 5 minutes. Conclusion: GLP may inhibit calcium overload and promote CaMK II a expression to protect epileptic neuron

    Cerebrovascular reactivity among native-raised high altitude residents: an fMRI study

    Get PDF
    Background: The impact of long term residence on high altitude (HA) on human brain has raised concern among researchers in recent years. This study investigated the cerebrovascular reactivity among native-born high altitude (HA) residents as compared to native sea level (SL) residents. The two groups were matched on the ancestral line, ages, gender ratios, and education levels. A visual cue guided maximum inspiration task with brief breath holding was performed by all the subjects while Blood-Oxygenation-Level-Dependent (BOLD) functional Magnetic Resonance Imaging (fMRI) data were acquired from them

    RNAi-mediated COPS3 gene silencing inhibits metastasis of osteogenic sarcoma cells

    Get PDF
    Metastatic disease is the primary cause of mortality among patients with osteogenic sarcoma (OGS). In this study, we aimed to identify the relationship of COPS3 gene expression to metastasis. Immunohistochemical staining for COPS3 was performed on 65 OGS samples (37 without and 28 with metastatic disease); 18.9% (7/37) of specimens from patients with no metastasis and 57.1% (16/28) of specimens from patients with metastasis showed intense staining of COPS3. Comparison of COPS3 expression between a poorly metastatic osteosarcoma cell line (SAOS-2) and highly metastatic osteosarcoma cell line (HOS) showed stronger expression of COPS3 in HOS cells. Inhibiting COPS3 function by siRNA resulted in reduced proliferation and migration of HOS cells. Inhibition of COPS3 gene downregulated expression of the MAPK signaling pathway, which has an important role in metastasis of OGS. Our results suggested that overexpression of the COPS3 gene might have important roles in metastasis of osteosarcoma cells

    Interactions among mitochondrial proteins altered in glioblastoma

    Get PDF
    Mitochondrial dysfunction is putatively central to glioblastoma (GBM) pathophysiology but there has been no systematic analysis in GBM of the proteins which are integral to mitochondrial function. Alterations in proteins in mitochondrial enriched fractions from patients with GBM were defined with label-free liquid chromatography mass spectrometry. 256 mitochondrially-associated proteins were identified in mitochondrial enriched fractions and 117 of these mitochondrial proteins were markedly (fold-change ≥2) and significantly altered in GBM (p ≤ 0.05). Proteins associated with oxidative damage (including catalase, superoxide dismutase 2, peroxiredoxin 1 and peroxiredoxin 4) were increased in GBM. Protein–protein interaction analysis highlighted a reduction in multiple proteins coupled to energy metabolism (in particular respiratory chain proteins, including 23 complex-I proteins). Qualitative ultrastructural analysis in GBM with electron microscopy showed a notably higher prevalence of mitochondria with cristolysis in GBM. This study highlights the complex mitochondrial proteomic adjustments which occur in GBM pathophysiology
    corecore