Work distribution functions for hysteresis loops in a single-spin system

We compute the distribution of the work done in driving a single Ising spin with a time-dependent magnetic field. Using Glauber dynamics we perform Monte-Carlo simulations to find the work distributions at different driving rates. We find that in general the work-distributions are broad with a significant probability for processes with negative dissipated work. The special cases of slow and fast driving rates are studied analytically. We verify that various work fluctuation theorems corresponding to equilibrium initial states are satisfied while a steady state version is not.Comment: 9 pages, 15 figure

Driving particle current through narrow channels using classical pump

We study a symmetric exclusion process in which the hopping rates at two chosen adjacent sites vary periodically in time and have a relative phase difference. This mimics a colloidal suspension subjected to external space and time dependent modulation of the diffusion constant. The two special sites act as a classical pump by generating an oscillatory current with a nonzero ${\cal DC}$ value whose direction depends on the applied phase difference. We analyze various features in this model through simulations and obtain an expression for the $\cal{DC}$ current via a novel perturbative treatment.Comment: Revised versio

Is gene therapy a good therapeutic approach for HIV-positive patients?

Despite advances and options available in gene therapy for HIV-1 infection, its application in the clinical setting has been challenging. Although published data from HIV-1 clinical trials show safety and proof of principle for gene therapy, positive clinical outcomes for infected patients have yet to be demonstrated. The cause for this slow progress may arise from the fact that HIV is a complex multi-organ system infection. There is uncertainty regarding the types of cells to target by gene therapy and there are issues regarding insufficient transduction of cells and long-term expression. This paper discusses state-of-the-art molecular approaches against HIV-1 and the application of these treatments in current and ongoing clinical trials

ROSUVASTATIN CALCIUM LOADED CHITOSAN NANOPARTICLES: PREPARATION EVALUATION AND IN VITRO RELEASE STUDIES

Objective: The objective of the present study was to develop sustained release biodegradable polymeric nanoparticles of rosuvastatin calcium. Methods: Nanoparticles were prepared by modified ionotropic gelation method using 3² full factorial designs. From the preliminary trials, the constraints for independent variables X1 (concentration. of chitosan) and X2 (concentration. of sodium tripolyphosphate) have been fixed. Factors included concentration of chitosan and sodium tripolyphosphate, have been examined to investigate effect on particle size, encapsulation efficiency, zeta potential, % release, scanning electron microscopy, Fourier transfer infrared study and X-ray diffraction and release study of rosuvastatin calcium nanoparticles. 0 Results: The prepared nanoparticles were white, free-flowing and spherical in shape. The infrared spectra showed stable character of rosuvastatin calcium in the drug-loaded nanoparticles and revealed the absence of drug polymer interactions. The chitosan nanoparticles have a particle diameter ranging approximately 114.5±3.61 to 724±.2.51 nm and a zeta potential-13.12 to-52.63 mV. The in vitro release behavior from all the drug loaded batches were found to follow first order and provided sustained release over a period of 10 h. The Zeta potential of all the batches were in the range of-13.12 to-52.63 mv. The release profiles of all batches were very well fitted by Korsmeyer Peppas model. Conclusion: The best-fit release kinetics was achieved with Korsmeyer peppas model. The release of rosuvastatin calcium was influenced by the drug to polymer ratio and particle size. These results indicate that rosuvastatin calcium nanoparticles could be effective in sustaining drug release for a prolonged period

Stochastic pump of interacting particles

We consider the overdamped motion of Brownian particles, interacting via particle exclusion, in an external potential that varies with time and space. We show that periodic potentials that maintain specific position-dependent phase relations generate time-averaged directed current of particles. We obtain analytic results for a lattice version of the model using a recently developed perturbative approach. Many interesting features like particle-hole symmetry, current reversal with changing density, and system-size dependence of current are obtained. We propose possible experiments to test our predictions.Comment: 4 pages, 2 figure

Lightweight Object Detection Ensemble Framework for Autonomous Vehicles in Challenging Weather Conditions

The computer vision systems driving autonomous vehicles are judged by their ability to detect objects and obstacles in the vicinity of the vehicle in diverse environments. Enhancing this ability of a self-driving car to distinguish between the elements of its environment under adverse conditions is an important challenge in computer vision. For example, poor weather conditions like fog and rain lead to image corruption which can cause a drastic drop in object detection (OD) performance. The primary navigation of autonomous vehicles depends on the effectiveness of the image processing techniques applied to the data collected from various visual sensors. Therefore, it is essential to develop the capability to detect objects like vehicles and pedestrians under challenging conditions such as like unpleasant weather. Ensembling multiple baseline deep learning models under different voting strategies for object detection and utilizing data augmentation to boost the models' performance is proposed to solve this problem. The data augmentation technique is particularly useful and works with limited training data for OD applications. Furthermore, using the baseline models significantly speeds up the OD process as compared to the custom models due to transfer learning. Therefore, the ensembling approach can be highly effective in resource-constrained devices deployed for autonomous vehicles in uncertain weather conditions. The applied techniques demonstrated an increase in accuracy over the baseline models and were able to identify objects from the images captured in the adverse foggy and rainy weather conditions. The applied techniques demonstrated an increase in accuracy over the baseline models and reached 32.75% mean average precision (mAP) and 52.56% average precision (AP) in detecting cars in the adverse fog and rain weather conditions present in the dataset. The effectiveness of multiple voting strategies for bounding box predictions on the dataset is also demonstrated. These strategies help increase the explainability of object detection in autonomous systems and improve the performance of the ensemble techniques over the baseline models

Robustness against parametric noise of non ideal holonomic gates

Holonomic gates for quantum computation are commonly considered to be robust against certain kinds of parametric noise, the very motivation of this robustness being the geometric character of the transformation achieved in the adiabatic limit. On the other hand, the effects of decoherence are expected to become more and more relevant when the adiabatic limit is approached. Starting from the system described by Florio et al. [Phys. Rev. A 73, 022327 (2006)], here we discuss the behavior of non ideal holonomic gates at finite operational time, i.e., far before the adiabatic limit is reached. We have considered several models of parametric noise and studied the robustness of finite time gates. The obtained results suggest that the finite time gates present some effects of cancellation of the perturbations introduced by the noise which mimic the geometrical cancellation effect of standard holonomic gates. Nevertheless, a careful analysis of the results leads to the conclusion that these effects are related to a dynamical instead of geometrical feature.Comment: 8 pages, 8 figures, several changes made, accepted for publication on Phys. Rev.

Development of stability indicating assay method for the simultaneous estimation of Metformin hydrochloride and Glipizide by RP-HPLC method

A simple, sensitive an isocratic RP-HPLC method for the estimation of Metformin Hydrochloride (MET) and Glipizide (GPZ) in combined dosage form using Inertsil C8 column (250.6 mm, 5 ) in an isocratic mode with mobile phase comprising Acetonitrile: Water (70:30) and one drop of Triethylamine. The flow rate was 1.0 ml/min and effluent was monitored at 222 nm. The retention times were found to be 3.40 min for MET and 4.44 min for GPZ. The assay exhibited a linear dynamic range of 100-500 g/ml of MET and 1-5 g/mL for GPZ .The calibration curves were linear (r = 0.9985 for MET and r = 0.9955 for GPZ) over the entire linear range. Recovery was found to be 99.94 % + .17 for MET and 99.61 % + 0.89 for GPZ. % RSD of system precision were observed 0.0429 for MET and 0.7212 for GPZ

Particle current in symmetric exclusion process with time-dependent hopping rates

In a recent study, (Jain et al 2007 Phys. Rev. Lett. 99 190601), a symmetric exclusion process with time-dependent hopping rates was introduced. Using simulations and a perturbation theory, it was shown that if the hopping rates at two neighboring sites of a closed ring vary periodically in time and have a relative phase difference, there is a net DC current which decreases inversely with the system size. In this work, we simplify and generalize our earlier treatment. We study a model where hopping rates at all sites vary periodically in time, and show that for certain choices of relative phases, a DC current of order unity can be obtained. Our results are obtained using a perturbation theory in the amplitude of the time-dependent part of the hopping rate. We also present results obtained in a sudden approximation that assumes large modulation frequency.Comment: 17 pages, 2 figure