Jedi's Light Sabre: Site Specific Photocleavage of Proteins with Light

ABSTRACT The ability of photoreagent to target and photocleave the protein backbone at a single site has been a considerable challenge for over decades. The structure of the photoreagent can be systematically modified to provide valuable information on the binding site recognition and photoreaction mechanisms. Many factors, for example, functional groups and overall charge present on the probe, conformations of the bound probe, protein size and amino acids present at the binding site, can affect the photocleavage reaction. A variety of spectroscopic methods (absorption, fluorescence and circular dichroism spectroscopies) were used to monitor the binding interaction. Peptide bond cleavage reactions were obtained from irradiation, at the probe absorption wavelength (~340 nm), of the probe/protein mixture, in the presence of an electron sink. The mechanism indicated the important role of aromatic cation radicals in the mechanistic path as obtained from laser flash photolysis studies. Computer docking studies can be used to provide strong support for the photocleavage and sequencing studies. The docked structures indicated the location of the probe in good proximity to the obtained cleavage site. In this short review, we focused mainly on few generic proteins, such as serum albumin, lysozyme and avidin. However, this strategy may be extended to other proteins with appropriate modifications, which could be useful in a rational design of novel photoreagents to target desired sites on proteins in future studies

Topology of event distribution as a generalized definition of phase transitions in finite systems

We propose a definition of phase transitions in finite systems based on topology anomalies of the event distribution in the space of observations. This generalizes all the definitions based on the curvature anomalies of thermodynamical potentials and provides a natural definition of order parameters. The proposed definition is directly operational from the experimental point of view. It allows to study phase transitions in Gibbs equilibria as well as in other ensembles such as the Tsallis ensemble.Comment: 4 pages, 3 figure

A Study of the Bulk Phase Transitions of the SU(2) Lattice Gauge Theory with Mixed Action

Using the finite size scaling theory, we re-examine the nature of the bulk phase transition in the fundamental-adjoint coupling plane of the SU(2) lattice gauge theory at $\beta_A = 1.25$ where previous finite size scaling investigations of the deconfinement phase transition showed it to be of first order for temporal lattices with four sites. Our simulations on $N^4$ lattices with N=6, 8, 10, 12 and 16 show an absence of a first order bulk phase transition. We find the discontinuity in the average plaquette to decrease approximately linearly with $N$. Correspondingly, the plaquette susceptibility grows a lot slower with the 4-volume of the lattice than expected from a first order bulk phase transition.Comment: LaTeX, 17 Pages; 7 Postscript Figures appende

Our experience of management of sub trochanteric fractures of femur by proximal femoral nail

Background: Sub trochanteric fractures of the femur remain some of the most challenging fractures. Most of the fractures result from trivial fall in the elderly; while in the younger age group, it's mainly due to road traffic accidents. Operative management is the preferred treatment. This study is intended to assess the outcome of the intramedullary fixation of sub trochanteric fractures with Proximal Femoral Nail (PFN).Methods: This study is a prospective, uncontrolled study of 40 cases of sub trochanteric fracture of femur admitted to a tertiary level hospital between August 2011 and November 2013; and treated with proximal femoral nails. Adults with recent sub trochanteric fracture of femur were included in this study; while patients less than eighteen years of age, pathologic fractures, periprosthetic fractures, and old neglected fractures were excluded from the study.  Results: In our study of 40 cases, there were 28 male and 12 female patients with mean age of 51.43 years (range 22-87 years). Based on Seinsheimer’s classification, type IIIA fractures accounted for majority (32.5%) of the cases. majority of patients, i.e. 35% (n=14) showed union at 20 weeks after surgery. Cases were followed up and assessed according to the Harris hip scoring system (Modified).The outcome was good to excellent in 82.9% cases.  Conclusions: From our study we conclude that PFN is a reliable minimally invasive implant for sub trochanteric fractures, with good to excellent functional outcome in the majority of cases.  

A Crystallized Treatise on Determinants of Motivational Environment in Oil and Natural Gas Corporation Limited (ONGC)

Technologies have become stakes and those companies who can turn strategy into action at jet speed can bring seamless changes in the organization. In this context motivation has become an important HR intervention in making human resources effective. Companies realized the importance of the motivation as the contribution of employees directly relates their vision and mission statements. Demotivated workforce can cause havoc in failing to meet the organizational objectives.  It has the role to develop and intensify the desire of every member of the organization to work effectively and efficiently in their roles. After employees are hired and trained, it is important to motivate them to get the desired efforts from them, to achieve organizational objectives. Owing to the stiff competition among the Multi Nationals in retaining them has become challenge, this paper focus on motivating the workforce by introducing various HR Interventions to motivate and retain for the benefit of the organizational objectives.  For this cause a range of motivational factors were considered for a critical assessment on motivational environment in ONGC. Keywords: Motivation, technology, environment, organizational objectives, workforce DOI: 10.7176/EJBM/13-11-03 Publication date:June 30th 202

Suppressing monopoles and vortices : A possibly smoother approach to scaling ?

Suppressing monopoles and vortices by introducing large chemical potentials for them in the Wilson action for the SU(2) lattice gauge theory, we study the nature of the deconfinement phase transition on N_\sigma^3 \times N_\tau lattices for N_\tau = 4, 5, 6 and 8 and N_\sigma = 8--16. Using finite size scaling theory, we obtain \omega = 1.93 \pm 0.03 for N_\tau = 4, in excellent agreement with universality. Corresponding determinations for the N_\tau = 5 and 6 lattices are also found to be in very good agreement with this estimate. The critical couplings for N_\tau= 4, 5, 6 and 8 lattices exhibit large shifts towards the strong coupling region when compared with the usual Wilson action, and suggest a lot smoother approach to scaling.Comment: 22 pages, LaTeX, 6 figures included, Very minor correction

Construction of a series of vectors for high throughput cloning and expression screening of membrane proteins from Mycobacterium tuberculosis

<p>Abstract</p> <p>Background</p> <p>One of the major challenges for membrane protein structural genomics is establishing high-throughput cloning and expression screening methods to obtain enough purified protein in a homogeneous preparation for structural and functional studies. Here a series of ligation independent cloning based vectors were constructed to address this challenge.</p> <p>Results</p> <p>The feasibility of these vectors was tested with 41 putative membrane proteins from <it>Mycobacterium tuberculosis</it>. The efficiency for direct cloning of these target genes from PCR products was 95% (39/41). Over 40% of cloned genes were overexpressed in <it>Escherichia coli </it>BL21 (DE3)-RP codon plus strain in the first round of expression screening. For those proteins which showed no expression, three protein fusion partners were prepared and it was found that each of the target proteins could be overexpressed by at least one of these fusions, resulting in the overexpression of two thirds of the cloned genes.</p> <p>Conclusion</p> <p>This expression platform features high throughput cloning, high flexibility for different constructs, and high efficiency for membrane protein overexpression, and is expected to be useful in membrane protein structural and functional studies.</p