3,215 research outputs found
(2-HyÂdroxyÂacetato-κO 1)bisÂ(1,10-phenanÂthroline-κ2 N,N′)copper(II) nitrate
In the title compound, [Cu(C2H3O3)(C12H8N2)2]NO3, the CuII atom is coordinated by two phenanthroline (phen) ligands and one carboxyl-O atom of a hyÂdroxyÂacetate anion in a distorted square-pyramidal geometry. The hyÂdroxy group of the hyÂdroxyÂacetate ligand links with the counter NO3
− anion via a pair of bifurcated O—H⋯O hydrogen bonds. The centroid–centroid distance of 3.5676 (14) Å between benzene rings of parallel phen ligands of adjacent molÂecules suggests the existence of π–π stacking. Weak interÂmolecular C—H⋯O hydrogen bonding is also present in the crystal structure
Experimental Implementation of Noncyclic and Nonadiabatic Geometric Quantum Gates in a Superconducting Circuit
Quantum gates based on geometric phases possess intrinsic noise-resilience
features and therefore attract much attention. However, the implementations of
previous geometric quantum computation typically require a long pulse time of
gates. As a result, their experimental control inevitably suffers from the
cumulative disturbances of systematic errors due to excessive time consumption.
Here, we experimentally implement a set of noncyclic and nonadiabatic geometric
quantum gates in a superconducting circuit, which greatly shortens the gate
time. And also, we experimentally verify that our universal single-qubit
geometric gates are more robust to both the Rabi frequency error and qubit
frequency shift-induced error, compared to the conventional dynamical gates, by
using the randomized benchmarking method. Moreover, this scheme can be utilized
to construct two-qubit geometric operations, while the generation of the
maximally entangled Bell states is demonstrated. Therefore, our results provide
a promising routine to achieve fast, high-fidelity, and error-resilient quantum
gates in superconducting quantum circuits
Experimental investigation of kinetic instabilities driven by runaway electrons in the EXL-50 spherical torus
In this study, the first observation of high-frequency instabilities driven
by runaway electrons has been reported in the EXL-50 spherical torus using a
high-frequency magnetic pickup coil. The central frequency of these
instabilities is found to be exponentially dependent on the plasma density,
similar to the dispersion relation of the whistler wave. The instability
frequency displays chirping characteristics consistent with the Berk-Breizman
model of beam instability. Theoretically, the excitation threshold of the
instability driven by runaway electrons is related to the ratio of the runaway
electron density to the background plasma density, and such a relationship is
first demonstrated experimentally in this study. The instability can be
stabilized by increasing the plasma density, consistent with the wave-particle
resonance mechanism. This investigation demonstrates the controlled excitation
of chirping instabilities in a tokamak plasma and reveals new features of these
instabilities, thereby advancing the understanding of the mechanisms for
controlling and mitigating runaway electrons
Coexistence and interference mitigation for WPANs and WLANs from traditional approaches to deep learning: a review
More and more devices, such as Bluetooth and IEEE 802.15.4 devices forming Wireless Personal Area Networks (WPANs) and IEEE 802.11 devices constituting Wireless Local Area Networks (WLANs), share the 2.4 GHz Industrial, Scientific and Medical (ISM) band in the realm of the Internet of Things (IoT) and Smart Cities. However, the coexistence of these devices could pose a real challenge—co-channel interference that would severely compromise network performances. Although the coexistence issues has been partially discussed elsewhere in some articles, there is no single review that fully summarises and compares recent research outcomes and challenges of IEEE 802.15.4 networks, Bluetooth and WLANs together. In this work, we revisit and provide a comprehensive review on the coexistence and interference mitigation for those three types of networks. We summarize the strengths and weaknesses of the current methodologies, analysis and simulation models in terms of numerous important metrics such as the packet reception ratio, latency, scalability and energy efficiency. We discover that although Bluetooth and IEEE 802.15.4 networks are both WPANs, they show quite different performances in the presence of WLANs. IEEE 802.15.4 networks are adversely impacted by WLANs, whereas WLANs are interfered by Bluetooth. When IEEE 802.15.4 networks and Bluetooth co-locate, they are unlikely to harm each other. Finally, we also discuss the future research trends and challenges especially Deep-Learning and Reinforcement-Learning-based approaches to detecting and mitigating the co-channel interference caused by WPANs and WLANs
Endothelial Atg7 Deficiency Ameliorates Acute Cerebral Injury Induced by Ischemia/Reperfusion
Ischemic strokes often result in cerebral injury due to ischemia/reperfusion (I/R). Although the local inflammatory responses are known to play a primary role in the brain I/R injury, the underlying mechanism remains unclear. In the current study, we investigated the effect of brain endothelial Atg7 (autophagy related 7) depletion in the acute brain injury induced by ischemia and reperfusion. Endothelial knockout of Atg7 in mice (Atg7 eKO) was found to significantly attenuate both the infarct volume and the neurological defects induced by I/R when compared to the controls. In fact, brain inflammatory responses induced by I/R were alleviated by the Atg7 eKO. Furthermore, an increased expression of pro-inflammatory cytokines, including IL-1β, IL-6, IL-8, and TNF-α, was observed in brain endothelial cells in response to oxygen/glucose depletion/reoxygenation, which was decreased by the shRNA-mediated Atg7 knockdown. Interestingly, Atg7 knockdown reduced IKKβ phosphorylation, leading to NF-κB deactivation and downregulation of the pro-inflammatory cytokines mRNA levels. Further, Atg7 transcriptional regulation function is independent of its role in autophagy. Taken together, our results demonstrated that brain endothelial Atg7 contributes to brain damage during I/R by modulating the expression of pro-inflammatory cytokines. Depletion of Atg7 in brain endothelium has a neuroprotective effect against the ischemia/reperfusion-induced acute cerebral injury during stroke
Computer-modified paramedian approach technique reduces failures and alleviates pain in lumbar puncture: a prospective comparative study
BackgroundThe conventional midline approach for lumbar puncture (MAT-LP) has a relatively low success rate of 70%. The paramedian approach can increase the effective puncture area and success rate but lacks standardized guidelines. This study evaluated a computer-modified paramedian approach technique (CMPAT) to optimize lumbar puncture using computational techniques.MethodsIn this prospective study, 120 patients underwent CMPAT-LP (n = 60) or MAT-LP (n = 60). Puncture failure was defined after 6 attempts. Failure rate, number of attempts, pain score, and complications were compared. Subgroup analysis was conducted for age (≥ 50 years).ResultsNo significant demographic differences existed between groups. Failure rates were 3.3% for CMPAT vs. 13.3% for MAT. Puncture attempts averaged 2.0 vs. 3.5 and pain scores were 2.7 vs. 4.1 for CMPAT and MAT, respectively. All outcomes were significantly improved with CMPAT, especially in elderly patients. No significant difference in complications was observed.ConclusionCompared to MAT, CMPAT-LP demonstrated lower failure rates, fewer puncture attempts, and less pain, without compromising safety. CMPAT may be superior and should be more widely implemented in clinical practice
Evaluating the efficiency of a nomogram based on the data of neurosurgical intensive care unit patients to predict pulmonary infection of multidrug-resistant Acinetobacter baumannii
BackgroundPulmonary infection caused by multidrug-resistant Acinetobacter baumannii (MDR-AB) is a common and serious complication after brain injury. There are no definitive methods for its prediction and it is usually accompanied by a poor prognosis. This study aimed to construct and evaluate a nomogram based on patient data from the neurosurgical intensive care unit (NSICU) to predict the probability of MDR-AB pulmonary infection.MethodsIn this study, we retrospectively collected patient clinical profiles, early laboratory test results, and doctors’ prescriptions (66 variables). Univariate and backward stepwise regression analyses were used to screen the variables to identify predictors, and a nomogram was built in the primary cohort based on the results of a logistic regression model. Discriminatory validity, calibration validity, and clinical utility were evaluated using validation cohort 1 based on receiver operating characteristic curves, calibration curves, and decision curve analysis (DCA). For external validation based on predictors, we prospectively collected information from patients as validation cohort 2.ResultsAmong 2115 patients admitted to the NSICU between December 1, 2019, and December 31, 2021, 217 were eligible for the study, including 102 patients with MDR-AB infections (102 cases) and 115 patients with other bacterial infections (115 cases). We randomly categorized the patients into the primary cohort (70%, N=152) and validation cohort 1 (30%, N=65). Validation cohort 2 consisted of 24 patients admitted to the NSICU between January 1, 2022, and March 31, 2022, whose clinical information was prospectively collected according to predictors. The nomogram, consisting of only six predictors (age, NSICU stay, Glasgow Coma Scale, meropenem, neutrophil to lymphocyte ratio, platelet to lymphocyte ratio), had significantly high sensitivity and specificity (primary cohort AUC=0.913, validation cohort 1 AUC=0.830, validation cohort 2 AUC=0.889) for early identification of infection and had great calibration (validation cohort 1,2 P=0.3801, 0.6274). DCA confirmed that the nomogram is clinically useful.ConclusionOur nomogram could help clinicians make early predictions regarding the onset of pulmonary infection caused by MDR-AB and implement targeted interventions
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