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Direct Shear Testing Study of the Interface Behavior between Steel Plate and Compacted Completely Decomposed Granite under Different Vertical Stresses and Suctions
No full textIn this paper, the shearing behavior of soil-steel interfaces sheared at different planes is examined using a modified suction-controlled direct shear apparatus (MDSA). Direct shear tests on soil-steel interfaces sheared at three shear planes at three different suction values were conducted. Test results show that matric suction has a significant influence on interface shear behavior and shear strength and that the critical (or minimum) interface shear strength depends on the applied matric suction. Net normal stress affects both peak and postpeak shear stresses of the interfaces and those of the pure soil. The suction envelope for the interfaces is nonlinear. The interface shear strength values from experimental results are compared with the values predicted from an existing analytical model that considers the influence of soil dilation. The results indicate that the analytical model is suitable for predicting the unsaturated interface shear strength of rough soil-steel interfaces. (C) 2017 American Society of Civil Engineers
Heterocorroles: corrole analogues containing heteroatom(s) in the core or at a meso-position
No full textCorroles are 18 aromatic macrocyclic systems having one direct pyrrole-pyrrole linkage leading to a contracted cavity compared to porphyrins. Corroles exhibit contrasting coordination chemistry and properties compared to porphyrins. Structural modification of corroles by introducing a heteroatom in their aromatic conjugation circuit i.e., either in the core or at a meso position leads to a new class of corrinoids called heterocorroles. The core modification strategy includes replacing one or two core nitrogen atom(s) with O, S or C atoms and meso-modification involves replacing the meso-carbon atom at the 10-position with NH, NR, O, S, Se or Si atoms. This review article presents an overview of the progress in heterocorrole chemistry including their syntheses, key structural aspects and properties
PEG mediated shape-selective synthesis of cubic Fe3O4 nanoparticles for cancer therapeutics
No full textA facile strategy for shape-selective synthesis of PEGylated Fe3O4 cubic magnetic nanoparticles (PCMN) by thermal decomposition of Fe (III) acetylacetonate was developed and explored their applications in drug delivery and hyperthermia. The structural analysis by XRD and TEM showed the formation of spinel-structured Fe3O4 nanoparticles of good crystallinity. The presence of carboxyl PEG group on the surface of PCMN provides colloidal stability, non-toxicity and protein resistance characteristics to them. These negatively charged PCMN have high electrostatic binding affinity for positively charged anticancer drug, doxorubicin hydrochloride (DOX) and followed pH responsive release behaviour. The in-vitro cytotoxicity studies using normal human fibroblast (NIH 3T3) cells did not show any significant toxicity when cells were treated with PCMN. However, DOX loaded PCMN (PCMN-DOX) exhibit good cellular internalization and substantial toxicity to mouse skin fibrosarcoma (WEHI-164) cells. In addition, the superparamagnetic nature of these particles with optimal magnetization and excellent specific absorption rate (SAR) under external AC magnetic field makes it a valuable system which can be further used as an effective heating agent for hyperthermia treatment of cancer. (C) 2017 Elsevier B.V. All rights reserved
Comparative Refolding of Guanidinium Hydrochloride Denatured Serum Albumin Assisted by Surfactants via Artificial Chaperone Protocol: Biophysical Insight
No full textNULL CONTROLLABILITY OF THE INCOMPRESSIBLE STOKES EQUATIONS IN A 2-D CHANNEL USING NORMAL BOUNDARY CONTROL
No full textIn this paper, we consider the Stokes equations in a two-dimensional channel with periodic conditions in the direction of the channel. We establish null controllability of this system using a boundary control which acts on the normal component of the velocity only. We show null controllability of the system, subject to a constraint of zero average, by proving an observability inequality with the help of a Muntz-Szasz Theorem
Ethoxysilane appended M(II) complexes and their SiO2/MCM-41 supported forms as catalysts for efficient oxidation of secondary alcohols
No full textDivalent transition metal complexes ML2 (M = Mn 1; Co 2; Cu 3; Zn 4), possessing an ethoxysilane group as a part of the bidentate Schiff base ((E)-1-((3-(triethoxysilyl) propylimino) methyl)naphthalen-2-ol (L)), have been synthesized. While the copper complex 3 has been isolated in an analytically pure form and characterized by spectroscopic and single crystal XRD studies, the formation of complexes 1, 2, and 4 in solution has been verified by ESI mass spectroscopy and subsequently used for further catalyst preparation without their isolation. Treatment of the in situ formed 1-4 with pre-activated silica in boiling toluene produces the catalysts 5-8, respectively. The copper complex 3 was also treated with MCM-41 in boiling toluene to obtain CuL2@MCM-41 (9). Elemental analysis (CHN), ESI MS, IR, UV-vis., C-13 & Si-29 NMR, EPR, P-XRD, TGA, BET, SEM and TEM have been used to characterize the compounds. Compounds 3 (homogeneous) and 5-9 (heterogeneous) have been utilized as catalysts in the oxidation of secondary alcohols to corresponding carbonyls in the presence of H2O2, t-BuOOH, and C6H5C (CH3)(2)OOH. 3 and 9 have shown better catalytic activity than the rest of the catalysts investigated. Combination of 9 with H2O2 is the best catalytic system due to its efficiency and reusability besides being environment friendly. (C) 2017 Elsevier B.V. All rights reserved
Delamination of Pearlitic Steel Wires: The Defining Role of Prior-Drawing Microstructure
No full textThis article reports the occasional (< 10 pct of the actual production) delamination of pearlitic wires subjected to a drawing strain of similar to 2.5. The original wire rods which exhibited post-drawing delamination had noticeably lower axial alignment of the pearlite: 22 +/- 5 pct vs 34 +/- 4 pct in the nondelaminated wires. Although all wires had similar through-thickness texture and stress gradients, delaminated wires had stronger gradients in composition and higher hardness across the ferrite-cementite interface. Carbide dissolution and formation of supersaturated ferrite were clearly correlated with delamination, which could be effectively mitigated by controlled laboratory annealing at 673 K. Direct observations on samples subjected to simple shear revealed significant differences in shear localizations. These were controlled by pearlite morphology and interlamellar spacing. Prior-drawing microstructure of coarse misaligned pearlite thus emerged as a critical factor in the wire drawing-induced delamination of the pearlitic wires
Biophysical insight into the interaction mechanism of plant derived polyphenolic compound tannic acid with homologous mammalian serum albumins
No full textNumerous phenolic compounds have been reported in the last decade that have a good antioxidant property and interaction affinity towards mammalian serum albumins. In the present study, we have utilized mammalian serum albumins as a model protein to examine their comparative interaction property with polyphenolic compound tannic acid (TA) by using various spectroscopic and calorimetric methods We have also monitored the esterase and antioxidant activity of mammalian serum albumins in the absence and presence of TA. The obtain results recommended that the TA have a good binding affinity (similar to 10(4) to 10(6) M-1) towards mammalian serum albumins and shows double sequential binding sites, which depends on the concentration of TA that induced the conformational alteration which responsible for the thermal stability of proteins. Binding affinity, structural transition and thermodynamic parameters were calculated from spectroscopic and calorimetric method reveals that non-covalent interaction causes partial conformational alteration in the secondary structure of protein ie.; increase in alpha-helical content with decrease in beta-sheet, random coil and other structure. Meanwhile, we have found that esterase activities of serum albumins were also stabilized against hydrolysis and shows higher antioxidant activity in the presence of TA because albumins its self have an immense antioxidant activity beside TA. (C) 2017 Elsevier B.V. All rights reserved
A new and informative [a,b,c,d] nomenclature for one-pot multistep transformations: a simple tool to measure synthetic efficiency
No full textDomino, cascade and tandem reactions constitute the most efficient and creative chemical transformations with a huge domain of synthetic utility and applications. A number of reactions may be achieved in a single pot, accompanied by the formation of new rings and new bonds, leading towards higher molecular complexity. A lack of one unified, yet informative descriptor often understates the synthetic ingenuity of certain highly creative transformations. In this review, we propose a new tetra-coordinated [a,b,c,d] nomenclature which takes into account and displays the basic parameters which generally indicate the level of efficiency of a chemical transformation. An almost exhaustive set of one-pot multistep reactions may be described by this system and this review is an attempt to display the one-pot multistep transformations reported from our group and to classify them based on our proposed descriptor