Measuring thermodynamic length

Thermodynamic length is a metric distance between equilibrium thermodynamic states. Among other interesting properties, this metric asymptotically bounds the dissipation induced by a finite time transformation of a thermodynamic system. It is also connected to the Jensen-Shannon divergence, Fisher information and Rao's entropy differential metric. Therefore, thermodynamic length is of central interest in understanding matter out-of-equilibrium. In this paper, we will consider how to define thermodynamic length for a small system described by equilibrium statistical mechanics and how to measure thermodynamic length within a computer simulation. Surprisingly, Bennett's classic acceptance ratio method for measuring free energy differences also measures thermodynamic length.Comment: 4 pages; Typos correcte

Nucleotide-dependent DNA gripping and an end-clamp mechanism regulate the bacteriophage T4 viral packaging motor.

ATP-powered viral packaging motors are among the most powerful biomotors known. Motor subunits arranged in a ring repeatedly grip and translocate the DNA to package viral genomes into capsids. Here, we use single DNA manipulation and rapid solution exchange to quantify how nucleotide binding regulates interactions between the bacteriophage T4 motor and DNA substrate. With no nucleotides, there is virtually no gripping and rapid slipping occurs with only minimal friction resisting. In contrast, binding of an ATP analog engages nearly continuous gripping. Occasional slips occur due to dissociation of the analog from a gripping motor subunit, or force-induced rupture of grip, but multiple other analog-bound subunits exert high friction that limits slipping. ADP induces comparably infrequent gripping and variable friction. Independent of nucleotides, slipping arrests when the end of the DNA is about to exit the capsid. This end-clamp mechanism increases the efficiency of packaging by making it essentially irreversible

Balancing Trade-off between Data Security and Energy Model for Wireless Sensor Network

An extensive effort to evolve various routing protocol to ensure optimal data delivery in energy efficient way is beneficial only if there is additional means of security process is synchronized. However, the security process consideration introduces additional overhead thus a security mechanism is needed to accomplish an optimal trade-off that exists in-between security as well as resource utilization especially energy. The prime purpose of this paper is to develop a process of security in the context of wireless sensor networks (WSN) by introducing two types of sensor node deployed with different capabilities. The proposed algorithm Novel Model of Secure Paradigm (N-MSP) which is further integrated with WSN. However, this algorithm uses a Hash-based Message Authentication Code (HMAC) authentication followed by pairwise key establishment during data aggregation process in a WSN. The extensive simulation carried out in a numerical platform called MATLAB that depicts that the proposed N-MSP achieves optimal processing time along with energy efficient pairwise key establishment during data aggregation proces

Study of lipid and non-lipid effects of statins in hypertensive patients

Background: Hypertension is one of the commonest diseases affecting the mankind which is associated with endothelial dysfunction and left ventricular dysfunction and hence the study is aimed to observe the effects of statins on endothelial and left ventricular dysfunction.Methods: 15 hypertensive patients were given atorvastatin for 4 weeks and compared with sex and aged matched 15 controls after a detailed Clinical history, clinical examination, biochemical investigations, chest X-ray, electrocardiogram, echocardiogram and Doppler study of brachial artery.Results: Both study group and control group consisted of 10 males and 5 females who have dyslipidemia, endothelial and ventricular dysfunction. After a 4 weeks of study, in study group, flow mediated brachial artery diameter (FMD%) increased significantly (11.39%, P<0.01) from 7.37% to 18.76%, mean LV systolic function (EF) improved significantly (10.73%, P:<0.01) from 54.6% to 60.65%, LV diastolic function was normalized in 7 (46.67%) and improved in 5 (33.33%) patients, the mean systolic and diastolic BP decreased significantly (12.03%, P<0.01, 10.29%, P<0.01) from 149.66mmHg to 131.66mmHg and from 90.66mmHg to 81.33mmHg respectively, while in control group FMD increased marginally (1.07%) from 7.50% to 8.57%, LV EF marginally improved (1.47%) to 54.86% from 54.06%; no improvement in diastolic dysfunction, mean systolic and diastolic BP decreased marginally (6.25%, 0.74%) from 149.33 mmHg to 140mmHg and from 90.33mmHg to 89.66mmHg respectively.Conclusions: Statins improve not only lipid profile but also endothelial and LV functions which resulted in significant reduction of systolic and diastolic BP. Hence it is reasonable to treat all hypertensive patients with statins besides concurrent hypertension treatment

A double-blind randomized placebo-controlled study of low dose mirtazapine once daily in patients of major depressive disorders on escitalopram

Background: The SSRIs being used as 1st line therapy in treatment of depression have delayed therapeutic effect which makes the patient vulnerable to an increased risk of suicide and decreased adherence to the treatment and will prematurely discontinue the therapy. The present study was conducted to evaluate if low dose mirtazapine-escitalopram combination therapy has any add on benefit over monotherapy with escitalopram.Methods: In a single-centered, comparative study involving patients with depression attending the out-patient after screening and exclusion, 60 eligible patients were randomly assigned to receive tablet mirtazapine 7.5 mg plus tablet escitalopram 10 mg intervention or tablet escitalopram 10 mg plus placebo intervention in a double-blind 6-week treatment phase. The primary outcome measure was the change in the 17-item Hamilton Depression Rating Scale (HDRS) and Montgomery-Asberg Depression Rating Scale (MADRS) score from baseline. Participants were evaluated at baseline, 1st, 2nd,4th and 6th week. Results were analyzed using Chi-Square test for adverse effects and independent t-test analysis for efficacy parameter.Results: In the analysis of results at 6th week the numbers of patients achieved remission in mirtazapine group are more with a p-value of 0.018 which is significant and the numbers of responders in mirtazapine group are also more which is statistically significant on chi-square test. There is no significant difference was observed between the two groups with reference to occurrence of adverse effect.Conclusions: Adding low dose mirtazapine has an added benefit in terms of efficacy and getting remission early with more number of responders in the treatment of major depression

Pressure effects on the magnetic structure in La0.5Ca0.5-xSrxMnO3 (0.1 -< x -< 0.4) manganites

The effect of high pressure (0 - 8 GPa) on the magnetic structure of polycrystalline samples of La0.5Ca0.5-xSrxMnO3 (0.1 -< x -< 0.4) manganites at 5 K is investigated using neutron diffraction technique. Application of pressure is found to modify the previously reported magnetic structure, observed under ambient conditions, in these compounds [I. Dhiman et al., Phys. Rev. B 77, 094440 (2008)]. In x = 0.1 composition, at 4.6(2) GPa and beyond, A-type antiferromagnetic structure is found to coexist with CE-type antiferromagnetic phase, observed at ambient pressure, with TN ~ 150 K. For x = 0.3 sample, as a function of pressure the CE-type phase is fully suppressed at 2.3(1) GPa and A-type antiferromagnetic phase is favored. Further Sr doping at x = 0.4, the A-type antiferromagnetic phase is observed at ambient pressure and for T < TN (~ 250K). This phase is retained in the studied pressure range. However, the magnetic moment progressively reduces with increasing pressure, indicating the suppression of A-type antiferromagnetic phase. The present study brings out the fragile nature of the CE-type antiferromagnetic state in half doped manganites as a function of pressure and disorder \sigma 2. We observe that pressure required for destabilizing the CE-type antiferromagnetic state is reduced with increasing disorder \sigma 2. External pressure and changing A-site ionic radii have analogous effect on the magnetic structure.Comment: 9 pages, 6 figures, 1 table, To appear in Physical Review