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111.
Kanaparthi Ramesh Luwei Chen Fengxi Chen Yan Liu Zhan Wang Yi-Fan Han 《Catalysis Today》2008,131(1-4):477-482
Kinetic study of CO oxidation in combination with experiments of temperature-programmed oxidation (TPO) and reduction (TPR) have been performed on various unsupported crystalline manganese oxides (MnOx); while the reactivity shows an order of MnO ≤ MnO2 < Mn2O3 in a mixture of unit ratio of O2/CO at/below 523 K. We propose that under the current conditions the interaction of adsorbed CO and O is mainly responsible for CO2 formation on Mn2O3 and MnO2 catalysts, following either the Langmuir–Hinshelwood mechanism or Eley–Rideal mechanism. Meanwhile, direct evidence from transient CO oxidation suggests that the Mars-van-Krevelen mechanism may occur for all catalysts simultaneously, especially, it is predominant for the MnO catalyst. The evidence of structural modifications during reaction was confirmed by Raman spectra obtained from used MnO. 相似文献
112.
Kanaparthi Ramesh Fengxi Chen Armando Borgna Chilukoti Srilakshmi Yi-Fan Han 《Topics in Catalysis》2008,49(3-4):209-215
Manganese oxides supported on mesoporous SBA-15 catalysts have been prepared by molecularly designed dispersion method, using Mn(II) and Mn(III) acetylacetonate organic precursors. XRD and in situ Raman studies demonstrate the formation of highly dispersed Mn2O3 and Mn3O4 nanoparticles on SBA-15 for the calcined samples. The detailed decomposition mechanism was studied by using in situ DRIFTS. Acetylacetonate ligands are stable up to 573 K and can only be completely removed by oxygen treatment. 相似文献
113.
Mechanical tests were carried out to study the behavior of albite reinforced Al 6061 matrix composite produced through the
liquid vortex method and heat treated to T6 treatment. The matrix material Al 6061 was also tested as a control material for
comparison. The hardness, ultimate tensile strength (UTS), compression strength, and Young’s modulus were found to be higher
than those of the control alloy. The reinforcement noticeably enhances the dislocation density in the matrix upon cooling
from the solutionizing temperature. The dislocations that serve as heterogeneous nucleation sites for strengthening precipitates
during subsequent aging treatments, after the precipitation kinetics of the matrix of the composite, were compared to the
control alloy. A higher density of dislocations and a higher density of intermediate precipitates were observed. There was
a marginal improvement of tensile strength, compression, and hardness with aging. 相似文献
114.
Dr. Laura Fourmois Dr. Florent Poyer Dr. Aude Sourdon Delphine Naud-Martin Dr. Sounderya Nagarajan Dr. Rahima Chennoufi Dr. Eric Deprez Dr. Marie-Paule Teulade-Fichou Dr. Florence Mahuteau-Betzer 《Chembiochem : a European journal of chemical biology》2021,22(14):2457-2467
Mitochondria are involved in many cellular pathways and dysfunctional mitochondria are linked to various diseases. Hence efforts have been made to design mitochondria-targeted fluorophores for monitoring the mitochondrial status. However, the factors that govern the mitochondria-targeted potential of dyes are not well-understood. In this context, we synthesized analogues of the TP-2Bzim probe belonging to the vinyltriphenylamine (TPA) class and already described for its capacity to bind nuclear DNA in fixed cells and mitochondria in live cells. These analogues ( TP-1Bzim, TPn-2Bzim, TP1+-2Bzim, TN-2Bzim ) differ in the cationic charge, the number of vinylbenzimidazolium branches and the nature of the triaryl core. Using microscopy, we demonstrated that the cationic derivatives accumulate in mitochondria but do not reach mtDNA. Under depolarisation of the mitochondrial membrane, TP-2Bzim and TP1+-2Bzim translocate to the nucleus in direct correlation with their strong DNA affinity. This reversible phenomenon emphasizes that these probes can be used to monitor ΔΨm variations. 相似文献
115.
Michael L. Mohler Arunima Sikdar Suriyan Ponnusamy Dong-Jin Hwang Yali He Duane D. Miller Ramesh Narayanan 《International journal of molecular sciences》2021,22(4)
Traditional endocrine therapy for prostate cancer (PCa) has been directed at suppression of the androgen receptor (AR) signaling axis since Huggins et al. discovered that diethylstilbestrol (DES; an estrogen) produced chemical castration and PCa tumor regression. Androgen deprivation therapy (ADT) still remains the first-line PCa therapy. Insufficiency of ADT over time leads to castration-resistant PCa (CRPC) in which the AR axis is still active, despite castrate levels of circulating androgens. Despite the approval and use of multiple generations of competitive AR antagonists (antiandrogens), antiandrogen resistance emerges rapidly in CRPC due to several mechanisms, mostly converging in the AR axis. Recent evidence from multiple groups have defined noncompetitive or noncanonical direct binding sites on AR that can be targeted to inhibit the AR axis. This review discusses new developments in the PCa treatment paradigm that includes the next-generation molecules to noncanonical sites, proteolysis targeting chimera (PROTAC), or noncanonical N-terminal domain (NTD)-binding of selective AR degraders (SARDs). A few lead compounds targeting each of these novel noncanonical sites or with SARD activity are discussed. Many of these ligands are still in preclinical development, and a few early clinical leads have emerged, but successful late-stage clinical data are still lacking. The breadth and diversity of targets provide hope that optimized noncanonical inhibitors and/or SARDs will be able to overcome antiandrogen-resistant CRPC. 相似文献
116.
Selin Sagbas Suner Subhra Mohapatra Ramesh S. Ayyala Venkat R. Brethanabotla Nurettin Sahiner 《应用聚合物科学杂志》2021,138(24):50576
Catechin (CAT) was crosslinked with trimethylolpropane triglycidyl ether (TMPTGE) to obtain degradable poly(CAT) particles in a single step. Spherical p(CAT) particles with tens of micrometer size range and an isoelectronic point at pH 1.2 were obtained. The hydrolytic degradation of p(CAT) particles provided sustainable and extended release with 264 mg/g CAT release within 10 days at pH 7.4. The antioxidant capacity of 55.0 ± 0.9 μg/ml gallic acid equivalent in terms of total phenol content, and 0.88 ± 0.3 μmol/g trolox equivalent were estimated for p(CAT) particles displaying strong radical scavenging capability. Blood clotting and hemolysis assays demonstrated dose-dependent blood compatibility revealing higher blood compatibility for p(CAT) particles up to 10 μg/ml concentration. The cytotoxicity results show that p(CAT) particles have almost no toxicity for CCD841 normal colon cells at 250 μg/ml concentration in 24 h incubation time giving ~97% cell viability, whereas CAT molecules only provide ~34% cell viability. 相似文献
117.
In this paper, a new approach proposed for modelling the three-dimensional (3D) topography produced on abrasive water jet (AWJ) cut surface is presented. It makes use of the trajectory of jet, predicted from the theory of ballistics and Bitter’s theory of erosion for material removal, for numerically simulating the cutting front. The 2D topography at different depths of the cut surface is generated by considering the trajectories on the cutting front and the abrasive particles impacting the walls of cut surface randomly. For realistic generation of topography on cut surfaces, several instantaneous profiles generated in each region of cut are superimposed to obtain an effective profile. The nature of effective profiles thus predicted is analyzed and validated using power spectral density analysis. The effective profiles predicted at different depths are in turn used to generate the 3D topography of AWJ cut surface. Results obtained with the proposed model are validated with the experimental results. 相似文献
118.
F. Xue J.J. Wang G. Sheng Esther Huang Y. Cao H.H. Huang Paul Munroe R. Mahjoub Y.L. Li Valanoor Nagarajan L.Q. Chen 《Acta Materialia》2013,61(8):2909-2918
Domain stability and structures in Pb(Zr0.3Ti0.7)O3/Pb(Zr0.7Ti0.3)O3 bilayer films under different substrate strains are studied using the phase field method. It is demonstrated that the domain structure of the bilayer film is very different from those of the corresponding single layer films grown on the same silicon substrate with an incoherent interface. Moreover, the predicted rhombohedral domains in the Pb(Zr0.7Ti0.3)O3 layer of the bilayer film have smaller sizes than those in the single layer case. These results are compared with experimental observations and previous thermodynamic analyses. The polarization distributions of the ferroelectric–paraelectric bilayer are analyzed as a function of the thickness of the bilayer film, where there is a “ferroelectric proximity effect” due to dipole–dipole interactions. The phase diagrams for both the bilayer and single layer films as a function of temperature and effective in-plane substrate strain are constructed. 相似文献
119.
Ramesh B. Kasetti Prabhavathi Maddineni Bindu Kodati Bhavani Nagarajan Sam Yacoub 《International journal of molecular sciences》2021,22(22)
Elevated intraocular pressure (IOP) is a major risk factor in developing primary open angle glaucoma (POAG), which is the most common form of glaucoma. Transforming growth factor-beta 2 (TGFβ2) is a pro-fibrotic cytokine that plays an important role in POAG pathogenesis. TGFβ2 induced extracellular matrix (ECM) production, deposition and endoplasmic reticulum (ER) stress in the trabecular meshwork (TM) contribute to increased aqueous humor (AH) outflow resistance and IOP elevation. Drugs which alter the glaucomatous fibrotic changes and ER stress in the TM may be effective in reducing ocular hypertension. Astragaloside IV (AS.IV), a novel saponin isolated from the roots of Astragalus membranaceus, has demonstrated antifibrotic and ER stress lowering effects in various tissues during disease conditions. However, the effect of AS.IV on glaucomatous TM fibrosis, ER stress and ocular hypertension has not been studied. Primary human TM cells treated with AS.IV decreased TGFβ2 induced ECM (FN, Col-I) deposition and ER stress (KDEL, ATF4 and CHOP). Moreover, AS.IV treatment reduced TGFβ2 induced NF-κB activation and αSMA expression in TM cells. We found that AS.IV treatment significantly increased levels of matrix metalloproteases (MMP9 and MMP2) and MMP2 enzymatic activity, indicating that the antifibrotic effects of AS.IV are mediated via inhibition of NF-κB and activation of MMPs. AS.IV treatment also reduced ER stress in TM3 cells stably expressing mutant myocilin. Interestingly, the topical ocular AS.IV eye drops (1 mM) significantly decreased TGFβ2 induced ocular hypertension in mice, and this was associated with a decrease in FN, Col-1 (ECM), KDEL (ER stress) and αSMA in mouse TM tissues. Taken together, the results suggest that AS.IV prevents TGFβ2 induced ocular hypertension by modulating ECM deposition and ER stress in the TM. 相似文献
120.
Silicon - Nowadays, the starring attentions of the polylactic acid based composites are improved due to environmental awareness and diminution of petroleum oil. The bio-plastics were restricted to... 相似文献