Synthesis towards synthetic adenosine receptor

Adenosine is a biologically important molecule as it acts as local modulator with cytoprotective function in the body. Adenosine accumulates in the extracellular space in response to metabolic stress and cell damage, and elevations in extracellular adenosine level are found in conditions like myocardial ischemia, hypoxia, inflammation and trauma. Its abnormal concentration therefore could be a marker of many diseases. Therefore determining its concentration can help understand the physiological state of the body. However its selective detection by synthetic receptors is not possible till date. Efforts have been made here to design molecular tweezer for adenosine. Multistep synthesis was done to synthesize two clamps, namely the π-π stacking clamp and the hydrogen bonding clamp for the proposed tweezer. These two clamps in coordination with Zn+2 ions intended to form a pre-organized tweezers molecule for more favorable complexation with adenosine

Crossover from magnetostatic to exchange coupling in La0.67Ca0.33MnO3/YBa2Cu3O7/La0.67Ca0.33MnO3 heterostructures

The influence of YBa2Cu3O4 (YBCO) superconductor layer (S-layer) with varying thickness d-YBCO = 20 to 50 nm on the magnetic coupling between two La0.67Ca0.33MnO3 (LCMO) ferromagnet layers (F-layer, thickness d-LCMO = 50 nm) in F/S/F heterostructures (HSs) was investigated by measuring global magnetization (M) in a temperature (T) range = 2 - 300 K and magnetic field (H) range = 0 - 10 kOe. All the HSs were superconducting with critical temperature (Tc) decreasing from = 78 to 36 K with decrease in d-YBCO, whereas the ferromagnetic ordering temperature Tm = 250 K did not change much. Systematically measured M-H loops of all HSs at both T > Tc and T < Tc show three main results- (a) the two step magnetic reversal above Tc converts into a four step reversal below Tc in HSs with d-YBCO >= 30 nm, (b) the magnetic field corresponding to the additional two switching steps and their magnitude show characteristic evolution with T and d-YBCO and (c) the HS with d-YBCO = 20 nm shows radically different behaviour, where the two step magnetic reversal above Tc continues to persist below Tc and converts into a single step reversal at T << Tc. The first two results indicate magnetostatic coupling between the magnetic domains and the vortices across the two F/S interfaces resulting in reversal dynamics different from that deep within the LCMO layers. Whereas, the result c reveals indirect exchange coupling between LCMO layers through the superconducting YBCO layer, which is a clear experimental evidence of coexistence of ferromagnetism and superconductivity in nm scale F/S/F HSs expected theoretically by C.A.R. Sa de Melo (Physica C 387, 17-25 (2003)).Comment: 23 pages, 7 figures, accepted in JPC

(R1971) Analysis of Feedback Queueing Model with Differentiated Vacations under Classical Retrial Policy

This paper analyzes an M/M/1 retrial queue under differentiated vacations and Bernoulli feedback policy. On receiving the service, if the customer is not satisfied, then he may join the retrial group again with some probability and demand for service or may leave the system with the complementary probability. Using the probability generating functions technique, the steady-state solutions of the system are obtained. Furthermore, we have obtained some of the important performance measures such as expected orbit length, expected length of the system, sojourn times and probability of server being in different states. Using MATLAB software, we have represented the graphical interpretation of the results obtained. Finally, the cost is optimized using the parabolic method

(R1881) Impatient Customers in Queueing System with Optional Vacation Policies and Power Saving Mode

In this manuscript, a queueing system with two optional vacation policies, power-saving mode under reneging and retention of reneged customers in both vacations is analyzed. If the server is free, it chooses either of the vacations, classical vacation or working vacation. During vacations, the customers may get impatient due to delays and may leave the system, but they are retained in the system with some convincing mechanisms. On vacation completion, if the system is empty, the server is turned off to facilitate better utilization of the resources. Some of the operating system characteristics are derived using the probability generating functions technique. The numerical results are graphically represented by using MATLAB software

Study of feedback queueing system with unreliable waiting server under Multiple Differentiated Vacation Policy

This manuscript analyses a queueing system with Bernoulli schedule feedback of customers, unreliable waiting server under differentiated vacations. The unsatisfied customer may again join the queue with probability α, following Bernoulli schedule. The stationary solution is obtained for the model with aid of Probability Generating function technique. Some important system performance measures are derived and graphical behaviour of these measures with some parameters is analyzed. Finally to obtain the optimal value of service rate for the model, cost optimization is performed through quadratic fit approach

Purification and characterization of a Bacillus subtilis keratinase and its prospective application in feed industry

We have isolated a Bacillus subtilis strain (RSE163) from soil and explored for keratinase production. Keratinase was purified using chromatographic methods (Sephadex G-75 and Q Sepharose) resulting in 8.42-fold purification with 3303 U/mg specific activity.The purified enzyme displayed 3 bands in close proximity between 20 to 22 kDa in SDS-PAGE which were apparent to the zone of hydrolysis in gelatin zymogram. Enzyme was stable over a wide pH (7.0-10.0) and temperature (30 °C to 70 °C) range with optimum activity at pH 9.0 and 60 °C. Keratinase activity was stimulated in presence of Mn2+, β-mercaptoethanol and surfactants (Triton-X and Tween-80) and inhibited by Fe3+, Cd2+, K+, PMSF (phenyl methane sulfonyl fluoride) and other chelating and reducing agents. The enzyme efficiently hydrolyzed a variety of complex protein substrates (chicken feather, keratin hydrolyzate and casein) and enzyme kinetics parameters were determined using Lineweaver Burk plot (Km = 6.6 mg/ml, Vmax = 5 U/ml/min). Hydrolyzed feather keratin obtained through fermentation with B. subtilis RSE163 has been explored for its cytotoxicity using liver cell line (HepG2). No cytotoxicity has been determined up to 0.015% concentration of hydrolyzed product indicating its potential applicability as feed supplement

FPT Approximations for Capacitated/Fair Clustering with Outliers

Clustering problems such as $k$-Median, and $k$-Means, are motivated from applications such as location planning, unsupervised learning among others. In such applications, it is important to find the clustering of points that is not ``skewed'' in terms of the number of points, i.e., no cluster should contain too many points. This is modeled by capacity constraints on the sizes of clusters. In an orthogonal direction, another important consideration in clustering is how to handle the presence of outliers in the data. Indeed, these clustering problems have been generalized in the literature to separately handle capacity constraints and outliers. To the best of our knowledge, there has been very little work on studying the approximability of clustering problems that can simultaneously handle both capacities and outliers. We initiate the study of the Capacitated $k$-Median with Outliers (C$k$MO) problem. Here, we want to cluster all except $m$ outlier points into at most $k$ clusters, such that (i) the clusters respect the capacity constraints, and (ii) the cost of clustering, defined as the sum of distances of each non-outlier point to its assigned cluster-center, is minimized. We design the first constant-factor approximation algorithms for C$k$MO. In particular, our algorithm returns a (3+\epsilon)-approximation for C$k$MO in general metric spaces, and a (1+\epsilon)-approximation in Euclidean spaces of constant dimension, that runs in time in time $f(k, m, \epsilon) \cdot |I_m|^{O(1)}$, where $|I_m|$ denotes the input size. We can also extend these results to a broader class of problems, including Capacitated k-Means/k-Facility Location with Outliers, and Size-Balanced Fair Clustering problems with Outliers. For each of these problems, we obtain an approximation ratio that matches the best known guarantee of the corresponding outlier-free problem.Comment: Abstract shortened to meet arxiv requirement