5,771 research outputs found

    Dynamical invariants in non-Markovian quantum state diffusion equation

    Full text link
    We find dynamical invariants for open quantum systems described by the non-Markovian quantum state diffusion (QSD) equation. In stark contrast to closed systems where the dynamical invariant can be identical to the system density operator, these dynamical invariants no longer share the equation of motion for the density operator. Moreover, the invariants obtained with from bi-orthonormal basis can be used to render an exact solution to the QSD equation and the corresponding non-Markovian dynamics without using master equations or numerical simulations. Significantly we show that we can apply these dynamic invariants to reverse-engineering a Hamiltonian that is capable of driving the system to the target state, providing a novel way to design control strategy for open quantum systems.Comment: 6 pages, 2 figure

    Higher-order solutions to non-Markovian quantum dynamics via hierarchical functional derivative

    Full text link
    Solving realistic quantum systems coupled to an environment is a challenging task. Here we develop a hierarchical functional derivative (HFD) approach for efficiently solving the non-Markovian quantum trajectories of an open quantum system embedded in a bosonic bath. An explicit expression for arbitrary order HFD equation is derived systematically. Moreover, it is found that for an analytically solvable model, this hierarchical equation naturally terminates at a given order and thus becomes exactly solvable. This HFD approach provides a systematic method to study the non-Markovian quantum dynamics of an open system coupled to a bosonic environment.Comment: 5 pages, 2 figure

    Diethylene glycol poisoning and liver function following accidental diethylene glycol injection

    Get PDF
    The aim of the present study was to investigate the hepatotoxic effects of accidental intravenous diethylene glycol (DEG) poisoning in patients with liver disease. Clinical manifestations were recorded and liver function tests were carried out for 64 patients with liver disease who had been accidentally treated intravenously with DEG. Comparisons were made between the poisoned and non-poisoned groups. Of the 64 cases with preexisting liver disease, 15 cases (23.4 %) developed toxic presentations after exposure to DEG. All cases were men. Twelve of the 15 poisoned patients (80 %)died within seven days. The intravenous administration of DEG resulted in only mild liver function impairment. Gender (p = 0.039) and the severity of jaundice prior to DEG administration were risk factors related to the occurrence of toxin-induced renal failure (p < 0.006). The results suggest that DEG may worsen liver damage in patients with preexisting liver disease. However, our study demonstrated only mild, transient alterations in patients’ baseline liver functions. Severe liver damage secondary to DEG was only occasionally seen in patients with concomitant renal failure

    KCNN2 polymorphisms and cardiac tachyarrhythmias

    Get PDF
    Potassium calcium-activated channel subfamily N member 2 (KCNN2) encodes an integral membrane protein that forms small-conductance calcium-activated potassium (SK) channels. Recent studies in animal models show that SK channels are important in atrial and ventricular repolarization and arrhythmogenesis. However, the importance of SK channels in human arrhythmia remains unclear. The purpose of the present study was to test the association between genetic polymorphism of the SK2 channel and the occurrence of cardiac tachyarrhythmias in humans. We enrolled 327 Han Chinese, including 72 with clinically significant ventricular tachyarrhythmias (VTa) who had a history of aborted sudden cardiac death (SCD) or unexplained syncope, 98 with a history of atrial fibrillation (AF), and 144 normal controls. We genotyped 12 representative tag single nucleotide polymorphisms (SNPs) across a 141-kb genetic region containing the KCNN2 gene; these captured the full haplotype information. The rs13184658 and rs10076582 variants of KCNN2 were associated with VTa in both the additive and dominant models (odds ratio [OR] 2.89, 95% confidence interval [CI] = 1.505-5.545, P = 0.001; and OR 2.55, 95% CI = 1.428-4.566, P = 0.002, respectively). After adjustment for potential risk factors, the association remained significant. The population attributable risks of these 2 variants of VTa were 17.3% and 10.6%, respectively. One variant (rs13184658) showed weak but significant association with AF in a dominant model (OR 1.91, CI = 1.025-3.570], P = 0.042). There was a significant association between the KCNN2 variants and clinically significant VTa. These findings suggest an association between KCNN2 and VTa; it also appears that KCNN2 variants may be adjunctive markers for risk stratification in patients susceptible to SCD

    Effects of Inter-set Inspiratory Muscle Activation on Post High-intensity Resistance Exercise Autonomic Regulation, Baroreflex Sensitivity, and Blood Pressure

    Get PDF
    Inspiratory muscle exercise and slow breathing have been demonstrated to improve blood pressure control, possibly via an improved sympatho/vagal balance mechanism. Purpose: To test the hypothesis that inter-set inspiratory muscle exercise would attenuate the increase of sympatho/vagal activity ratio and the reduction of baroreflex sensitivity after high-intensity resistance exercise. Methods: A total of 14 recreational active males (n=8, aged= 24±1yrs, BMI=22±1 kg/m2) and females (n=6, aged=24±1yrs, BMI=22±2 kg/m2) were recruited and underwent maximum muscle strength (1RM), maximum inspiratory pressure (PImax) determination after familiarization. Participants were asked to engage in 4 acute bouts of high-intensity resistance exercise (bench press, bicep curl, and squat exercise at 80%1RMÍ10repsÍ5setsÍ1.5min rest interval) with no inter-set breathing control (CON), slow breathing (10 breaths/min, SB), 30%PImax, and 60%PImax by using a randomized, repeated measures study design. Blood pressure, brachial-ankle pulse wave velocity(baPWV), hemodynamic parameters, heart rate variability (HRV), and baroreflex sensitivity (BRS) were obtained at Pre, Post, and Post-30 and Post-60 minutes. Twenty-four-hour ambulatory blood pressure monitoring (24hr AMBP) was also performed following exercise to determine average real variability (ARV), the indicator of blood pressure variability. Female participants were tested during the early follicular phase to avoid possible confounding effects from the menstrual cycle. Results: Compared with the Pre, HR significantly increased at Post in all treatments and remained elevated at Post-30 min in CON (P=0.005) and 60%PImax (P=0.03). Cardiac output increased at Post in CON (P=0.05) and 60%PImax(P=0.04), whereas stroke volume and mean arterial pressure were maintained. There was no time and treatment difference in post-exercise blood pressure, 24-hour AMBP, and baPWV. Compared with the Pre, LF/HF ratio was significantly higher at Post in CON (P=0.001) and SB (P=0.03), whereas 30%PImax and 60%PImax did not elicit significant changes. BRS was significantly reduced at Post in CON (P=0.04), yet it was maintained and significantly higher (P=0.03) at Post-60 min after the 30%PImax session. There were no group differences on 24hrAMBP ARV, despite 30%PImax appeared to elicit lower variability on systolic blood pressure. Conclusions: Compared with no breathing control, inter-set inspiratory muscle activation with resistance at 30%PImax appears effective in maintaining autonomic regulation and baroreflex sensitivity when engaging in high-intensity resistance exercise in apparently healthy young adults

    Noncontact Diffuse Correlation Tomography of Human Breast Tumor

    Get PDF
    Our first step to adapt our recently developed noncontact diffuse correlation tomography (ncDCT) system for three-dimensional (3-D) imaging of blood flow distribution in human breast tumors is reported. A commercial 3-D camera was used to obtain breast surface geometry, which was then converted to a solid volume mesh. An ncDCT probe scanned over a region of interest on the mesh surface and the measured boundary data were combined with a finite element framework for 3-D image reconstruction of blood flow distribution. This technique was tested in computer simulations and in vivo human breasts with low-grade carcinoma. Results from computer simulations suggest that relatively high accuracy can be achieved when the entire tumor is within the sensitive region of diffuse light. Image reconstruction with a priori knowledge of the tumor volume and location can significantly improve the accuracy in recovery of tumor blood flow contrasts. In vivo imaging results from two breast carcinomas show higher average blood flow contrasts (5.9- and 10.9-fold) in the tumor regions compared to the surrounding tissues, which are comparable with previous findings using diffuse correlation spectroscopy. The ncDCT system has the potential to image blood flow distributions in soft and vulnerable tissues without distorting tissue hemodynamic

    LncRNA-disease association prediction method based on heterogeneous information completion and convolutional neural network

    Full text link
    The emerging research shows that lncRNA has crucial research value in a series of complex human diseases. Therefore, the accurate identification of lncRNA-disease associations (LDAs) is very important for the warning and treatment of diseases. However, most of the existing methods have limitations in identifying nonlinear LDAs, and it remains a huge challenge to predict new LDAs. In this paper, a deep learning model based on a heterogeneous network and convolutional neural network (CNN) is proposed for lncRNA-disease association prediction, named HCNNLDA. The heterogeneous network containing the lncRNA, disease, and miRNA nodes, is constructed firstly. The embedding matrix of a lncRNA-disease node pair is constructed according to various biological premises about lncRNAs, diseases, and miRNAs. Then, the low-dimensional feature representation is fully learned by the convolutional neural network. In the end, the XGBoot classifier model is trained to predict the potential LDAs. HCNNLDA obtains a high AUC value of 0.9752 and AUPR of 0.9740 under the 5-fold cross-validation. The experimental results show that the proposed model has better performance than that of several latest prediction models. Meanwhile, the effectiveness of HCNNLDA in identifying novel LDAs is further demonstrated by case studies of three diseases. To sum up, HCNNLDA is a feasible calculation model to predict LDAs

    Simultaneous measurement of deep tissue blood flow and oxygenation using noncontact diffuse correlation spectroscopy flow-oximeter

    Get PDF
    We report a novel noncontact diffuse correlation spectroscopy flow-oximeter for simultaneous quantification of relative changes in tissue blood flow (rBF) and oxygenation (Δ[oxygenation]). The noncontact probe was compared against a contact probe in tissue-like phantoms and forearm muscles (n = 10), and the dynamic trends in both rBF and Δ[oxygenation] were found to be highly correlated. However, the magnitudes of Δ[oxygenation] measured by the two probes were significantly different. Monte Carlo simulations and phantom experiments revealed that the arm curvature resulted in a significant underestimation (~-20%) for the noncontact measurements in Δ[oxygenation], but not in rBF. Other factors that may cause the residual discrepancies between the contact and noncontact measurements were discussed, and further comparisons with other established technologies are needed to identify/quantify these factors. Our research paves the way for noncontact and simultaneous monitoring of blood flow and oxygenation in soft and vulnerable tissues without distorting tissue hemodynamics
    corecore