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排序方式: 共有437条查询结果,搜索用时 15 毫秒
71.
Eusebio Chiefari Maria Mirabelli Sandro La Vignera Sinan Tanyola Daniela Patrizia Foti Antonio Aversa Antonio Brunetti 《International journal of molecular sciences》2021,22(20)
Insulin resistance (IR) is a condition which refers to individuals whose cells and tissues become insensitive to the peptide hormone, insulin. Over the recent years, a wealth of data has made it clear that a synergistic relationship exists between IR, type 2 diabetes mellitus, and cancer. Although the underlying mechanism(s) for this association remain unclear, it is well established that hyperinsulinemia, a hallmark of IR, may play a role in tumorigenesis. On the other hand, IR is strongly associated with visceral adiposity dysfunction and systemic inflammation, two conditions which favor the establishment of a pro-tumorigenic environment. Similarly, epigenetic modifications, such as DNA methylation, histone modifications, and non-coding RNA, in IR states, have been often associated with tumorigenesis in numerous types of human cancer. In addition to these observations, it is also broadly accepted that gut microbiota may play an intriguing role in the development of IR-related diseases, including type 2 diabetes and cancer, whereas potential chemopreventive properties have been attributed to some of the most commonly used antidiabetic medications. Herein we provide a concise overview of the most recent literature in this field and discuss how different but interrelated molecular pathways may impact on tumor development. 相似文献
72.
In this study, the case properties and diffusion kinetics of AISI 440C and AISI 52100 steels borided in Ekabor-II powder were investigated by conducting a series of experiments at temperatures of 1123, 1173 and 1223 K for 2, 4 and 8 h.The boride layer was characterized by optical microscopy, X-ray diffraction technique and micro-Vickers hardness tester. X-ray diffraction analysis of boride layers on the surface of the steels revealed the existence of FeB, Fe2B and CrB compounds.The thickness of boride layer increases by increasing boriding time and temperature for all steels. The hardness of the boride compounds formed on the surface of steels AISI 52100 and AISI 440C ranged from 1530 to 2170 HV0.05 and 1620 to 1989 HV0.05, respectively whereas Vickers hardness values of untreated steels AISI 440C and AISI 52100 were 400 HV0.05 and 311 HV0.05, respectively. The activation energies (Q) of borided steels were 340.426 kJ/mol for AISI 440C and 269.638 kJ/mol for AISI 52100. The growth kinetics of the boride layers forming on the AISI 440C and AISI 52100 steels and thickness of boride layers were also investigated. 相似文献
73.
Poly(hydroxyethyl methacrylate) based magnetic nanoparticles for plasmid DNA purification from Escherichia coli lysate 总被引:1,自引:0,他引:1
Işık Perçin Veyis Karakoç Sinan Akgöl Erol Aksöz Adil Denizli 《Materials science & engineering. C, Materials for biological applications》2012,32(5):1133-1140
The aim of this study is to prepare poly(hydroxyethyl methacrylate-N-methacryloyl-(L)-histidine) [PHEMAH] magnetic nanoparticles for plasmid DNA (pDNA) purification from Escherichia coli (E. coli) cell lysate. Magnetic nanoparticles were produced by surfactant free emulsion polymerization. mPHEMAH nanoparticles were characterized by elemental analysis, Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), vibrating sample magnetometer (VSM), electron spin resonance (ESR), thermogravimetric analyses (TGA) and transmission electron microscopy (TEM). Surface area, average particle size and size distribution were also performed. Specific surface area of the mPHEMAH nanoparticles was found to be 1180 m2/g. Elemental analysis of MAH for nitrogen was estimated as 0.18 mmol/g polymer. The amount of pDNA adsorbed onto the mPHEMAH nanoparticles first increased and then reached a saturation value at around 1.0 mg/mL of pDNA concentration. Compared with the mPHEMA nanoparticles (50 μg/g polymer), the pDNA adsorption capacity of the mPHEMAH nanoparticles (154 mg/g polymer) was improved significantly due to the MAH incorporation into the polymeric matrix. The maximum pDNA adsorption was achieved at 25 °C. The overall recovery of pDNA was calculated as 92%. The mPHEMAH nanoparticles could be used six times without decreasing the pDNA adsorption capacity significantly. The results indicate that the PHEMAH nanoparticles promise high selectivity for pDNA. 相似文献
74.
模块化多电平换流器(Modular Multilevel Converter,MMC)作为一种新型的电压源换流器,被广泛应用于直流输电领域.电容的电压平衡问题在MMC中非常重要,随着MMC子模块个数的增多,电容电压的平衡变得越来越困难.本文提出了一种基于BP-PID的双闭环控制策略,通过控制调制波来控制子模块的工作状态... 相似文献
75.
76.
The 4340 steel is extensively utilized in several industries including automotive and aerospace for manufacturing a large number of structural components. Due to the importance of thermo-mechanical processing in the production of steels, the dynamic recrystallization (DRX) characteristics of 4340 steel were investigated. Namely, hot compression tests on 4340 steel have been performed in a temperature range of 900–1200 °C and a strain rate range of 0. 01–1 s?1 and the strain of up to 0. 9. The resulting flow stress curves show the occurrence of dynamic recrystallization. The flow stress values decrease with the increase of deformation temperature and the decrease of strain rate. The microstructure of 4340 steel after deformation has been studied and it is suggested that the evolution of DRX grain structures can be accompanied by considerable migration of grain boundaries. The constitutive equations were developed to model the hot deformation behavior. Finally based on the classical stress-dislocation relations and the kinematics of the dynamic recrystallization; the flow stress constitutive equations for the dynamic recovery period and dynamic recrystallization period were derived for 4340 steel, respectively. The validity of the model was demonstrated by demonstrating the experimental data with the numerical results with reasonable agreement. 相似文献
77.
78.
Nihat Sinan Isik Vedat Doyuran Resat Ulusay 《Bulletin of Engineering Geology and the Environment》2008,67(3):293-304
The deformation modulus of intact rock can be determined through standardized laboratory tests for heavily jointed rock masses
but this is very difficult, while in situ tests are time-consuming and expensive. In this study, the deformation modulus of
selected heavily jointed, sheared and/or blocky, weathered, weak greywacke, andesite and claystone were assessed, based on
pressuremeter tests, geo-engineering characterization and seismic surveys. Empirical equations based on GSI and RMR values
are proposed to indirectly estimate the deformation modulus of the greywackes. For the andesites, the spacing of the discontinuities
is greater than the length of the pressuremeter probe hence the intact rather than rock mass deformation modulus is obtained.
The pressuremeter test results from the claystones could not be correlated with the field data; the relationship between the
ratio of rock mass modulus to intact rock modulus and RQD appears to give a better estimation of the deformation modulus.
相似文献
79.
The effect of crystallinity and particle morphology of the submicron barium hexaferrite (BaFe12O19) powders on the magnetic properties was investigated on powders synthesized by solid-state calcination (BHF-c) and molten salt synthesis (BHF-m) methods. Solid-state calcination route was found to yield agglomerated powders with poor crystallinity, whereas molten salt synthesis resulted in well crystallized powders with an anisometric morphology. The saturation magnetization of the BHF-m and BHF-c samples is 59 emu/g, and 56 emu/g at 300 K, and 90 emu/g, and 86 emu/g at 10 K. The temperature dependence of magnetization of the BHF-m is higher and the increase in magnetocrystal anisotropy with decreasing temperature is also steeper than that of the BHF-c due to the higher crystallinity. The magnetocrystalline anisotropy constant, K, calculated from the Stoner–Wohlfarth theory, of the BHF-m and BHF-c powders is 14.24 and 10.14 HA2/kg, respectively. The higher effective anisotropy, Keff of the BHF-m is also confirmed through ferromagnetic resonance measurements. In conclusion, the higher crystallinity, slightly higher particle size and anisometric morphology of the BHF-m particles translated into higher magnetic properties and magnetocrystalline anisotropy. 相似文献
80.
Yapici E Reddy DR Miller LW 《Chembiochem : a European journal of chemical biology》2012,13(4):553-8, 489
Protein-protein interactions (PPIs) are central to biological processes and represent an important class of therapeutic targets. Here we show that the interaction between FK506-binding protein 12 fused to green fluorescent protein (GFP-FKBP) and the rapamycin-binding domain of mTor fused to Escherichia coli dihydrofolate reductase (FRB-eDHFR) can be sensitively detected (signal-to-background ratio (S/B)>100) and accurately quantified within an impure cell lysate matrix using a luminescence resonance energy transfer (LRET) assay. Ascomycin-mediated inhibition of GFP-FKBP-rapamycin-FRB-eDHFR complex formation was also detected at high S/B ratio (>80) and Z'-factor (0.89). The method leverages the selective, stable binding of trimethoprim (TMP)-terbium complex conjugates to eDHFR, and time-resolved, background-free detection of the long-lifetime (~ms) terbium-to-GFP LRET signal that indicates target binding. TMP-eDHFR labeling can be adapted to develop high-throughput screening assays and complementary, quantitative counter-screens for a wide variety of PPI targets with a broad range of affinities that may not be amenable to purification. 相似文献