Reduction in turbulence-induced non-linear dynamic vibration using tuned liquid damper (TLD)

In the present research work, an attempt is made to develop a coupled non-linear turbulence-structure-damper model in a finite volume-finite difference (FV-FD) framework. Tuned liquid damper (TLD) is used as the additional damping system along with inherent structural damping. Real-time simulation of flow-excited bridge box girder or chimney section and the vibration reduction using TLD can be performed using the developed model. The turbulent flow field around a structure is modeled using an OpenFOAM transient PISO solver, and the time-varying drag force is calculated. This force perturbs the structure, causing the sloshing phenomena of the attached TLD, modeled using shallow depth approximation, damping the flow-induced vibration of the structure. The structural motion with and without the attached TLD is modeled involving the FD-based Newmark-Beta method using in-house MATLAB codes. The TLD is tuned with the vortex-shedding frequency of the low-Reynolds number flows, and it is found to be reducing the structural excitation significantly. On the other hand, the high-Reynolds number turbulent flow exhibits a broadband excitation, for which by tuning the TLD with few frequencies obtained through investigations, a good reduction in vibration is observed.Comment: 6 pages, 12 figure

Sensitivity improvement in 2D and 3D HCCH spectroscopy using heteronuclear cross-polarization

A new method, which employs a sequence of heteronuclear-homonuclear-heteronuclear Hartmann-Hahn (HEHOHEHAHA) cross-polarization steps for obtaining through-bond H-C-C-H correlations in larger proteins (M r > 15 kDa), is presented. The method has significantly higher sensitivity compared to INEPTHOHAHA-INEPT-based techniques. An additional feature of this experiment is that well-phaseable spectra may be obtained with a minimal (4-step) phase cycle and, consequently, experimental time can be utilized towards obtaining high resolution in indirect dimensions. Results from 2D and 3D HEHOHEHAHA experiments on T4-lysozyme are presented.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43047/1/10858_2004_Article_BF00176006.pd

Evolution of corporate governance in India and its impact on the growth of the financial market: An empirical analysis (1995-2014)

Purpose The past few decades have seen a gradual convergence in corporate governance norms the world over, entailing a discernible shift towards shareholder primacy models. It holds particularly true of developing countries, many of which have steadily amended corporate governance norms to enhance the scope of shareholder rights. This is usually justified through the rationale that increasing protection for foreign investors and shareholders would mean greater investment in capital market and overall financial market development. In India, the shift coincides with a series of fundamental economic and financial policy reforms initiated in the 1990s: collectively and loosely referred to as “liberalisation”, this process marks a paradigm-shift from a tightly controlled welfare economy to one considerably more laissez-faire in its orientation. A fallout of which was that the need to attract and sustain foreign investments acquired an unprecedented significance. The purpose of this paper is to help the readers understand in this larger context the corporate law reform initiatives in India, particularly those pertaining to shareholder rights and allied issues. Design/methodology/approach This paper empirically tests the hypothesis that enhanced shareholder protection leads to greater levels of investments, and financial developments generally. It then uses regression analysis to detect if the change in corporate governance, making it more shareholder-friendly, has had any effect on growth in financial market. It is divided into two broad parts. The first tracks the evolution of corporate governance norms in India. A robust qualitative and quantitative analysis is used to determine the tilt towards a shareholder primacy regime that Indian corporate governance regime now displays. The second chapter deals with the regression analysis where the outcome variable is financial market growth, and explanatory variable is the change in the governance regime with relevant control variables. Findings The authors find that change in shareholder primacy corporate governance has little effect on financial market growth in India. The authors would suggest that instead of changing the law in books, more emphasis should be given to implement those regulations and increase the overall rule of law. Originality/value This is the first time that such a wide-scale study has been conducted in India, using Bayesian methods. It ought to be of immense value to professionals and academics both

Role of a non-canonical surface of Rad6 in ubiquitin conjugating activity

ABSTRACT Rad6 is a yeast E2 ubiquitin conjugating enzyme that monoubiquitinates histone H2B in conjunction with the E3, Bre1, but can non-specifically modify histones on its own. We determined the crystal structure of a Rad6∼Ub thioester mimic, which revealed a network of interactions in the crystal in which the ubiquitin in one conjugate contacts Rad6 in another. The region of Rad6 contacted is located on the distal face of Rad6 opposite the active site, but differs from the canonical E2 backside that mediates free ubiquitin binding and polyubiquitination activity in other E2 enzymes. We find that free ubiquitin interacts weakly with both non-canonical and canonical backside residues of Rad6 and that mutations of non-canonical residues have deleterious effects on Rad6 activity comparable to those observed to mutations in the canonical E2 backside. The effect of non-canonical backside mutations is similar in the presence and absence of Bre1, indicating that contacts with non-canonical backside residues govern the intrinsic activity of Rad6. Our findings shed light on the determinants of intrinsic Rad6 activity and reveal new ways in which contacts with an E2 backside can regulate ubiquitin conjugating activity

Nontarget DNA binding shapes the dynamic landscape for enzymatic recognition of DNA damage

The DNA repair enzyme human uracil DNA glycosylase (UNG) scans short stretches of genomic DNA and captures rare uracil bases as they transiently emerge from the DNA duplex via spontaneous base pair breathing motions. The process of DNA scanning requires that the enzyme transiently loosen its grip on DNA to allow stochastic movement along the DNA contour, while engaging extrahelical bases requires motions on a more rapid timescale. Here, we use NMR dynamic measurements to show that free UNG has no intrinsic dynamic properties in the millisecond to microsecond and subnanosecond time regimes, and that the act of binding to nontarget DNA reshapes the dynamic landscape to allow productive millisecond motions for scanning and damage recognition. These results suggest that DNA structure and the spontaneous dynamics of base pairs may drive the evolution of a protein sequence that is tuned to respond to this dynamic regime

Combined use of COSS and S.COSY for recording of pure-phase shift-scaled spectra

The phase characteristics of two chemical-shift scaling pulse sequences COSS and S.COSY have been analyzed, and a method for eliminating dispersive contributions to cross and diagonal peaks in the 2D spectra has been suggested. This results in pure absorption peak shapes for both diagonal- and cross-peak components and both acquire in-phase characteristics. An experimental demonstration of the procedure is given with a one-dimensional simplification due to practical limitations of the available 2D software