275 research outputs found

    Location- and observation time-dependent quantum-tunneling

    Full text link
    We investigate quantum tunneling in a translation invariant chain of particles. The particles interact harmonically with their nearest neighbors, except for one bond, which is anharmonic. It is described by a symmetric double well potential. In the first step, we show how the anharmonic coordinate can be separated from the normal modes. This yields a Lagrangian which has been used to study quantum dissipation. Elimination of the normal modes leads to a nonlocal action of Caldeira-Leggett type. If the anharmonic bond defect is in the bulk, one arrives at Ohmic damping, i.e. there is a transition of a delocalized bond state to a localized one if the elastic constant exceeds a critical value CcritC_{crit}. The latter depends on the masses of the bond defect. Superohmic damping occurs if the bond defect is in the site MM at a finite distance from one of the chain ends. If the observation time TT is smaller than a characteristic time τM∼M\tau_M \sim M, depending on the location M of the defect, the behavior is similar to the bulk situation. However, for T≫τMT \gg \tau_M tunneling is never suppressed.Comment: 17 pages, 2 figure

    Relation between clinical features and gastric emptying time in diabetic patients

    Get PDF
    BACKGROUND: Gastroparesis is characterized by delayed gastric emptying. This pathology is usually observed in patients with diabetes. One standard approach to quantitative assessment of gastric emptying is scintigraphic study. The aim of present study was to perform scintigraphic study of gastric emptying time in patient with diabetes and to find its correlation with patients' characteristics. MATERIALS AND METHODS: Gastric emptying was assessed in 19 patients with type 2 diabetes (mean age of 61.04 ± 6.09 years) and 6 healthy volunteers. Characteristics of the patients were sex, age, duration of diabetes, blood sugar and serum HbA1c level. RESULTS: Results of present study revealed that gastric emptying half time was significantly larger in patients with type 2 diabetes as compared with healthy volunteers (P-value < 0.05). While correlation of sex, age, duration of diabetes and blood sugar with gastric emptying time was not statistically significant, HbA1c level had significant effect on gastric emptying time. CONCLUSION: Results of this prospective study indicated that level of serum HbA1c is an effecting factor on gastric emptying time in patients with type 2 diabetes; however, these preliminary findings should be validated in larger and well-designed studies. Copyright © 2015 Via Medica

    Study on genetic variability of Cassidula aurisfelis (snail) by random amplified polymorphic DNAs

    Get PDF
    The genetic variability among individuals of Cassidula aurisfelis from Setiu Wetland, Terengganu Darul Iman was examined by using the random amplified polymorphic DNA (RAPD) technique. Ten oligonucleotide primers were screened and three primers were selected (OPA 02, OPA 04 and OPA 10)to amplify DNA from five samples of C. aurisfelis from Setiu Wetland, Terengganu. A total of 28 RAPD bands (RAPDs) with 17 polymorphic bands (60.71%) with size ranging from 300 – 1750 bp were scored from the population. Genetic distance for samples ranges from 0.135 to 0.269. Similarity index of samples ranges from 0.7179 to 0.8649 (mean 0.7810 ± 0.0497)

    Causal network inference using biochemical kinetics

    Get PDF
    Motivation: Networks are widely used as structural summaries of biochemical systems. Statistical estimation of networks is usually based on linear or discrete models. However, the dynamics of biochemical systems are generally non-linear, suggesting that suitable non-linear formulations may offer gains with respect to causal network inference and aid in associated prediction problems. Results: We present a general framework for network inference and dynamical prediction using time course data that is rooted in nonlinear biochemical kinetics. This is achieved by considering a dynamical system based on a chemical reaction graph with associated kinetic parameters. Both the graph and kinetic parameters are treated as unknown; inference is carried out within a Bayesian framework. This allows prediction of dynamical behavior even when the underlying reaction graph itself is unknown or uncertain. Results, based on (i) data simulated from a mechanistic model of mitogen-activated protein kinase signaling and (ii) phosphoproteomic data from cancer cell lines, demonstrate that non-linear formulations can yield gains in causal network inference and permit dynamical prediction and uncertainty quantification in the challenging setting where the reaction graph is unknown. © The Author 2014. Published by Oxford University Press

    Heart Rate detection using Photoplethysmography using Android Phone

    Get PDF
    This paper includes Heart Rate Detector system implemented by some modern hardware ICs and simple sensor circuit with software executable on both PC and android platform. Very first the bio-signals are extracted via photoplethysmography concept using PPG sensor into electric signal. Now at the next stage microprocessor is used to convert the bio-signal from analog to digital format. Some application software running on Windows and Android phone have been developed to display heart rate information and time domain waveform to users for health care monitoring. Some of the applications running on the android platform few of them have been developed to display the heart rate information and some health care monitoring system. This project includes the RF modules which having the major impact and plays the predominant role in it. In future, pure wireless technology will be used instead of RF modules DOI: 10.17762/ijritcc2321-8169.15032

    Geometric robustness and dynamic response management by structural topometry optimisation to reduce the risk for squeak and rattle

    Get PDF
    Historically, squeak and rattle (S&amp;R) sounds have been among the top quality problems and a major contributor to the warranty costs in passenger cars. Geometric variation is among the main causes of S&amp;R. Though, geometric variation analysis and robust design techniques have been passively involved in the open-loop design activities in the predesign-freeze phases of car development. Despite the successful application of topometry optimisation to enhance attributes such as weight, durability, noise and vibration and crashworthiness in passenger cars, the implementation of closed-loop structural optimisation in the robust design context to reduce the risk for S&amp;R has been limited. In this respect, the main obstacles have been the demanding computational resources and the absence of quantified S&amp;R risk evaluation methods. In this work, a topometry optimisation approach is proposed to involve the geometric variation analysis in an attribute balancing problem together with the dynamic response of the system. The proposed method was used to identify the potential areas of a door component that needed structural reinforcement. The main objective was to enhance the design robustness to minimise the risk for S&amp;R by improving the system response to static geometrical uncertainties and dynamic excitation

    The effect of adsorbed volatile organic compounds on an ultrathin water film measurement

    Get PDF
    Using surface plasmon resonance imaging (SPRi), we have recently shown for the first time the existence of a monolayer water film between droplets during dropwise condensation. This study examines the effect of adsorbed volatile organic compounds (VOCs) on the ultrathin film measurement using SPRi. Further, the work presents the proper surface-treatment process that enables measurements of the ultrathin water layer during high-speed imaging of dropwise condensation at 3000 frame per second. In this study, two methods were applied for cleaning the surface (gold-coated glass)-(1) standard cleaning procedure (SCP) using acetone, isopropyl alcohol, and deionized water and (2) SCP followed by air plasma cleaning. This work discusses the effect of the cleaning procedures on surface roughness, contact angle, and surface chemistry using atomic force microscopy, optical microscopy, and an X-ray photoelectron spectroscope meter. The results showed that SCP before the SPRi is a proper surface-treatment method. The effect of adsorbed VOCs during dropwise condensation on a surface treated with SCP was measured to be 0.0025 (reflectivity unit), which was 70% smaller than the reflectance associated with a monolayer water film. The results of this work confirm a monolayer water film observation during the dropwise condensation, which has been reported before

    Kallikrein-related peptidase 6 regulates epithelial-to-mesenchymal transition and serves as prognostic biomarker for head and neck squamous cell carcinoma patients

    Get PDF
    Background: Dysregulated expression of Kallikrein-related peptidase 6 (KLK6) is a common feature for many human malignancies and numerous studies evaluated KLK6 as a promising biomarker for early diagnosis or unfavorable prognosis. However, the expression of KLK6 in carcinomas derived from mucosal epithelia, including head and neck squamous cell carcinoma (HNSCC), and its mode of action has not been addressed so far. Methods: Stable clones of human mucosal tumor cell lines were generated with shRNA-mediated silencing or ectopic overexpression to characterize the impact of KLK6 on tumor relevant processes in vitro. Tissue microarrays with primary HNSCC samples from a retrospective patient cohort (n = 162) were stained by immunohistochemistry and the correlation between KLK6 staining and survival was addressed by univariate Kaplan-Meier and multivariate Cox proportional hazard model analysis. Results: KLK6 expression was detected in head and neck tumor cell lines (FaDu, Cal27 and SCC25), but not in HeLa cervix carcinoma cells. Silencing in FaDu cells and ectopic expression in HeLa cells unraveled an inhibitory function of KLK6 on tumor cell proliferation and mobility. FaDu clones with silenced KLK6 expression displayed molecular features resembling epithelial-to-mesenchymal transition, nuclear β-catenin accumulation and higher resistance against irradiation. Low KLK6 protein expression in primary tumors from oropharyngeal and laryngeal SCC patients was significantly correlated with poor progression-free (p = 0.001) and overall survival (p < 0.0005), and served as an independent risk factor for unfavorable clinical outcome. Conclusions: In summary, detection of low KLK6 expression in primary tumors represents a promising tool to stratify HNSCC patients with high risk for treatment failure. These patients might benefit from restoration of KLK6 expression or pharmacological targeting of signaling pathways implicated in EMT
    • …
    corecore