排序方式: 共有51条查询结果,搜索用时 31 毫秒
1.
2.
Ankur Srivastava Gargi Mishra Kshitij RB Singh Jay Singh Rampal Pandey Mrituanjay D. Pandey 《Luminescence》2023,38(7):1347-1357
Rare earth metals play a conspicuous role in magnetic resonance imaging (MRI) for detecting cancerous cells. The alkali metal potassium is a neurotransmitter in the sodium–potassium pump in biomedical sciences. This unique property of rare earth metals and potassium drew our attention to carry forward this study. Therefore, in this work, previously synthesized potassium (K) complexes formed by the reflux of 4-N,N-dimethylaminobenzoic acid (DBA) and potassium hydroxide in methanol, and named [(μ2–4-N,N-dimethylaminobenzoate-κO)(μ2–4-N,N-dimethylaminobenzoic acid-κO)(4-N,N-dimethylaminobenzoic acid-κO) potassium(I) coordination polymer)] were treated hydrothermally with La2O3 nanomaterials to obtain a nanohybrid La2O3/K-complex. After that, the K-complex was analyzed using single-crystal X-ray diffraction and 1H and 13C NMR spectroscopy. In addition, the structural and morphological properties of the as-prepared nanostructured La2O3/K-complex were also characterized, which involved an investigation using X-ray diffraction (XRD)spectroscopy, Fourier transform infrared (FTIR) spectroscopy, atomic force spectroscopy (AFM), transmission electron microscopy (TEM), and energy dispersive X-ray (EDX) analysis. After this, the electrochemical redox behaviour of the synthesized nanohybrid material was studied using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Therefore, the results from these studies revealed that the as-prepared material was a La2O3/K-complex that has a promising future role in sensing various analytes, as it showed effective electrocatalytic behaviour. 相似文献
3.
High dose tolerance to either bovine serum albumin (BSA) or fowl γ-globulin (FGG) was induced in CBA mice by neonatal injection. Tolerance to BSA lasted about 9 weeks, and that to FGG, about 18 weeks. Splenic B-cell function was analyzed using quantitative in vivo assays and in vitro limiting dilution analysis. Tolerogen-specific IgM- and non-IgM-producing B cells are depleted at least threefold in the spleens of tolerant mice. Tolerogen-specific T-helper-cell function was examined by immunization with haptenated antigens. Analysis of the recovery from tolerance indicates that the return to normal function in the tolerogen-specific B-cell and T helper fractions coincides with the return to normal responsiveness by the whole animal. 相似文献
4.
Two silicone coatings have been evaluated for barnacle adhesion. One coating is an unfilled hydrosilation cured polydimethylsiloxane (PDMS) network, while the other is a room temperature vulcanized (RTV), filled, ethoxysiloxane cured PDMS elastomer, RTV11?. The adhesion strength of one species of barnacle, Balanus eburneus, to the hydrosilation coatings is in the range of 0.37–0.60 kg cm‐2 while the corresponding range for RTV11 is 0.64–0.90 kg cm‐2. The easier release of B. eburneus from the hydrosilation cured network compared to RTV11 is discussed in relationship to differences in bulk and surface properties. Preliminary results suggest bulk modulus may be the most important parameter in determining barnacle adhesion strength. In light or mechanical property analysis, a re‐evaluation of surface properties and chemical stability is presented. 相似文献
5.
Paul S Bizouarne N Paul A Price MR Hansson GC Kieny MP Acres RB 《Cancer immunology, immunotherapy : CII》1999,48(1):22-28
The in vitro anti-proliferative properties of various supernatants from MUC1-expressing cell lines and of purified preparations
of MUC1 were evaluated. We have observed that supernatants from the MUC1- and MUC3-positive cell line T47D, but not from the
MUC1- and MUC4-positive cell line MCF7, were able to inhibit proliferation of cells from various haematopoietic cell lines.
Although the activity of T47D supernatants could be abrogated by immunodepletion of MUC1, immunopurified MUC1 from T47D was
unable to inhibit cell proliferation. Significantly, supernatants from mouse 3T3 cells transfected with a secreted form of
MUC1 or from BHK-21 cells infected with a recombinant vaccinia virus coding for the secreted form of MUC1, as well as preparations
of purified MUC1 from bile or urine, were likewise unable to inhibit T cell proliferation. Surprisingly, a crude mixture of
bile mucins had a suppressive effect on T cell growth. Our results suggest that other molecules, such as amino sugars or other
mucins, which can associate with MUC1, are likely to be responsible for the observed anti-proliferative effects of T47D cells.
Received: 20 August 1998 / Accepted: 3 December 1998 相似文献
6.
7.
Rajendra P Sujatha H Devendranath D Gunasekaran B Sashidhar R Subramanyam C Channakeshava 《Biomagnetic research and technology》2004,2(1):1
BACKGROUND: There are several reports that indicate a linkage between exposure to power frequency (50 - 60 Hz) magnetic fields with abnormalities in the early embryonic development of the chicken. The present study was designed to understand whether power frequency electromagnetic fields could act as an environmental insult and invoke any neurochemical or toxicological changes in developing chick embryo model. METHODS: Fertilized chicken eggs were subjected to continuous exposure to magnetic fields (50 Hz) of varying intensities (5, 50 or 100 microT) for a period of up to 15 days. The embryos were taken out of the eggs on day 5, day 10 and day 15. Neurochemical (norepinephrine and 5-hydroxytryptamine) and amino acid (tyrosine, glutamine and tryptophan) contents were measured, along with an assay of the enzyme glutamine synthetase in the brain. Preliminary toxicological investigations were carried out based on aminotransferases (AST and ALT) and lactate dehydrogenase activities in the whole embryo as well as in the liver. RESULTS: The study revealed that there was a significant increase (p < 0.01 and p < 0.001) in the level of norepinephrine accompanied by a significant decrease (p < 0.01 and p < 0.001) in the tyrosine content in the brain on day 15 following exposure to 5, 50 and 100 microT magnetic fields. There was a significant increase (p < 0.001) in glutamine synthetase activity resulting in the significantly enhanced (p < 0.001) level of glutamine in the brain on day 15 (for 100 microT only). The possible mechanisms for these alterations are discussed. Further, magnetic fields had no effect on the levels of tryptophan and 5-hydroxytryptamine in the brain. Similarly, there was no effect on the activity of either aminotransferases or lactate dehydrogenase in the whole embryo or liver due to magnetic field exposure. CONCLUSIONS: Based on these studies we conclude that magnetic field-induced changes in norepinephrine levels might help explain alterations in the circadian rhythm, observed during magnetic field stress. Also, the enhanced level of glutamine can act as a contributing factor for developmental abnormalities. 相似文献
8.
9.
Lees CJ Apostolopoulos V Acres B Ong CS Popovski V McKenzie IF 《Cancer immunology, immunotherapy : CII》2000,48(11):644-652
MUC1 is a mucin over-expressed in breast cancer and a proposed target for immunotherapy. By immunising mice with MUC1 conjugated
to mannan (M-FP), CD8+ MHC-class-I restricted cytotoxic T lymphocytes (CTL), of high CTL precursor (CTLp) frequency (1/8000) and with significant
tumour protection, can be induced. The effect of various cytokines [interleukin-2 (IL-2), IL-4, IL-6, IL-7, interferon γ (IFNγ),
and granulocyte/macrophage-colony-stimulating factor (GM-CSF)] on the MUC1 CTL immune response was investigated (a) by measuring
the frequencies of CTLp in mice immunised with vaccinia virus constructs containing recombinant cytokines and M-FP, or (b)
by immunising cytokine- or cytokine-receptor-knockout (−/−) mice with M-FP. Vaccinia virus (VV) constructs containing recombinant
cytokines were used either individually or in combination in vivo with M-FP immunisation. M-FP immunisations combined with
VV-IL-2, VV-IL-7 and VV-GM-CSF, and combinations of VV-IFNγ + VV-IL-2, VV-IFNγ + VV-IL-4 or VV-GM-CSF + VV-IL-7 increased
CTLp frequencies up to threefold (1/17 666: M-FP + VV-GM-CSF + VV-IL-7) compared to M-FP (1/77 500) alone. By contrast, M-FP
combined with VV-IL-4 decreased the CTLp frequency threefold whereas VV-IL-6 and VV-IFNγ had no effect. Studies in cytokine-
and cytokine-receptor-gene-knockout (−/−) mice demonstrated that mice that are IL-2 −/− and IL-7 receptor −/− produce the
same CTLp response to M-FP as do control mice, whereas responses in the IL-6 −/−, IL-10 −/− and IFNγ−/− mice were marginally
improved and responses to M-FP in IL-4 −/− and tumour necrosis factor receptor 2 −/− mice were weaker. In spite of the increase
in CTLp frequency, this was not reflected in an in vivo tumour model. Tumour challenges using MUC1+ P815 cells, demonstrated that the addition of cytokines had little additive effect on the already effective tumour-regression
capabilities of M-FP alone.
Received: 24 September 1998 / Accepted: 21 September 1999 相似文献
10.