577 research outputs found
Optimally controlled non-adiabatic quantum state transmission in the presence of quantum noise
Pulse controlled non-adiabatic quantum state transmission (QST) was proposed
many years ago. However, in practice environmental noise inevitably damages
communication quality in the proposal. In this paper, we study the optimally
controlled non-adiabatic QST in the presence of quantum noise. By using the
Adam algorithm, we find that the optimal pulse sequence can dramatically
enhance the transmission fidelity of such an open system. In comparison with
the idealized pulse sequence in a closed system, it is interesting to note that
the improvement of the fidelity obtained by the Adam algorithm can even be
better for a bath strongly coupled to the system. Furthermore, we find that the
Adam algorithm remains powerful for different number of sites and different
types of Lindblad operators, showing its universality in performing optimal
control of quantum information processing tasks
Genistein attenuates ischemia/reperfusion injury in rat kidneys via enhancement of antioxidant defense mechanisms: Activation of Nrf-2/HO-1 signaling
Purpose: To investigate the protective role of genistein against ischemic reperfusion (I/R) injury in rat kidneys.Methods: Group I (control, n = 10) consisted of animals that were not operated on while group II (sham, n = 10) were animals surgically operated on, similar to I/R group without renal bilateral ischemia. Group III (genistein, n = 10) consisted of animals administered 10 mg/kg genistein by oral gavage for 7 consecutive days while group IV (I/R, n = 10) animals were subjected to 45 min of renal bilateral ischemia followed by 24 h of reperfusion. Group V (genistein+I/R, n = 10) received 10 mg/kg genistein by oral gavage for 7 consecutive days and then subjected to 45 min of renal bilateral ischemia followed by 24 h of reperfusion. Renal function, total oxidant capacity and total antioxidant status in serum were evaluated in the rats. Further, reactive oxygen species generation as well as levels of protein carbonyl, lipid peroxidation, and enzymatic and non-enzymatic antioxidants were determined. Nrf-2 (nuclear factor (erythroid-derived 2)-like 2) and HO-1 (Heme oxygenase-1) expressions were determined by western blot.Results: Pre-treatment with genistein (10 mg/kg) significantly (p < 0.001)Â ameliorated I/R induced renal damage by reducing the levels of serum markers. Genistein pre-treatment significantly decreased (p <0.001) I/R injury induced-ROS, lipid peroxides and protein carbonyl content (p < 0.001). I/R injury significantly (p < 0.001) decreased non-enzymatic and enzymatic antioxidant activities. Genistein pretreatment also prevented renal I/R injury by significantly up-regulating Nrf-2, HO-1 expressions and antioxidant status.Conclusion: Thus, genistein may be therapeutically useful against kidney I/R injury by improving antioxidant defense mechanisms.Keywords: Oxidative stress, Genistein, Ischemic reperfusion injury, Renal damage, Antioxidant, Nuclear factor (erythroid-derived 2)-like 2, Heme oxygenase-1, Nrf-2, HO-1 Tropical Journal of Pharmaceutical Research is indexed by Science Citation Inde
Amentotaxus × hybridia (Taxaceae), a new natural Amentotaxus hybrid from southeast Yunnan province, China
During floristic surveys of Taxaceae in Hekou County, Yunnan Province, China, a putative natural hybrid between A. yunnanensis H.L. Li and A. hekouensis L.M. Gao was collected. Morphological and molecular evidence confirms its status as a natural hybrid. Amentotaxus × hybridia L.M. Gao has linear or linear-lanceolate leaves 6–13 cm × 1.0–1.5 cm, white stomatal bands with 34–40 rows on abaxial side, 2.5–3.5 mm, slightly wider than leaf margins; 3–6 seeds borne at the base of the branchlet, peduncle 1.3–1.6 cm long with 3–4 rows of persistent basal bracts
Determination of QPO properties in the presence of strong broad-band noise: a case study on the data of MAXI J1820+070
Accurate calculation of the phase lags of quasi-periodic oscillations (QPOs)
will provide insight into their origin. In this paper we investigate the phase
lag correction method which has been applied to calculate the intrinsic phase
lags of the QPOs in MAXI J1820+070. We find that the traditional additive model
between BBN and QPOs in the time domain is rejected, but the convolution model
is accepted. By introducing a convolution mechanism in the time domain, the
Fourier cross-spectrum analysis shows that the phase lags between QPOs
components in different energy bands will have a simple linear relationship
with the phase lags between the total signals, so that the intrinsic phase lags
of the QPOs can be obtained by linear correction. The power density spectrum
(PDS) thus requires a multiplicative model to interpret the data. We briefly
discuss a physical scenario for interpreting the convolution. In this scenario,
the corona acts as a low-pass filter, the Green's function containing the noise
is convolved with the QPOs to form the low-frequency part of the PDS, while the
high-frequency part requires an additive component. We use a multiplicative PDS
model to fit the data observed by Insight-HXMT. The overall fitting results are
similar compared to the traditional additive PDS model. Neither the width nor
the centroid frequency of the QPOs obtained from each of the two PDS models
were significantly different, except for the r.m.s. of the QPOs. Our work thus
provides a new perspective on the coupling of noise and QPOs.Comment: 13 pages, 8 figure
Decreased Blood Levels of Oxytocin in Ketamine-Dependent Patients During Early Abstinence
Background: Ketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist, is a common drug of abuse worldwide. Existing evidence suggest a disruption of oxytocin system involves in the development of addiction. In this study, we aimed to investigate the role of oxytocin in ketamine addiction by measuring the blood oxytocin levels in ketamine-dependent (KD) patients.Methods: Sixty-five KD patients and 65 controls were enrolled. Fasting plasma levels of oxytocin were determined at baseline and 1 and 2 weeks after ketamine withdrawal. Ketamine use variables, Beck Depression Inventory, Beck Anxiety Inventory (BAI), Visual Analog Scale for craving, and Childhood Trauma Questionnaire-short form were assessed in KD patients.Results: KD patients had significantly lower levels of oxytocin at baseline compared to controls (5.89 ± 2.13 vs. 9.53 ± 4.17 ng/mL, P < 0.001). Oxytocin levels increased after one (6.74 ± 2.63, P < 0.002) and 2 weeks (6.89 ± 2.69, P = 0.01) of withdrawal in KD patient despite the levels were still lower than controls (P = 0.001 and 0.002, respectively). The clinical variables did not correlate with baseline oxytocin levels except BAI scores, which showed a negative correlation with the levels (r = −0.263; P = 0.039).Conclusion: We found a distinctively reduced oxytocin level in KD patients and the level did not normalize after early abstinence. Lower oxytocin might be associated with anxious phenotype of ketamine dependence. These results suggest that oxytocin system dysregulated following chronic ketamine abuse and might provide insight in evaluating the potential therapeutic use of oxytocin for treating ketamine dependence
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