Effect of intraperitoneal infusion of ropivacaine combined with dexmedetomidine in patients undergoing total laparoscopic hysterectomy: a single-center randomized double-blinded controlled trial.

PURPOSE: To investigate the effect of intraperitoneal infusion of ropivacaine combined with dexmedetomidine and ropivacaine alone on the quality of postoperative recovery of patients undergoing total laparoscopic hysterectomy (TLH). METHODS: Female patients scheduled to undergo a TLH under general anesthesia at Fujian Maternity and Child Health Hospital were included. Before the end of pneumoperitoneum, patients were laparoscopically administered an intraperitoneal infusion of 0.25% ropivacaine 40 ml (R group) or 0.25% ropivacaine combined with 1 µg/kg dexmedetomidine 40 ml (RD group). The primary outcome was QoR-40, which was assessed before surgery and 24 h after surgery. Secondary outcomes included postoperative NRS scores, postoperative anesthetic dosage, the time to ambulation, urinary catheter removal, and anal exhaust. The incidence of dizziness, nausea, and vomiting was also analyzed. RESULTS: A total of 109 women were recruited. The RD group had higher QoR scores than the R group at 24 h after surgery (p < 0.05). Compared with the R group, NRS scores in the RD group decreased at 2, 6, 12, and 24 h after surgery (all p < 0.05). In the RD group, the time to the first dosage of postoperative opioid was longer and the cumulative and effective times of PCA compression were less than those in the R group (all p < 0.05). Simultaneously, the time to ambulation (p = 0.033), anal exhaust (p = 0.002), and urethral catheter removal (p = 0.018) was shortened in the RD group. The RD group had a lower incidence of dizziness, nausea, and vomiting (p < 0.05). CONCLUSION: Intraperitoneal infusion of ropivacaine combined with dexmedetomidine improved the quality of recovery in patients undergoing TLH. TRIAL REGISTRATION: ChiCTR2000033209, Registration Date: May 24, 2020.

Combined use of intranasal Dexmedetomidine and an oral novel formulation of Midazolam for sedation of young children during brain MRI examination: a prospective, single-center, randomized controlled trial.

BACKGROUND: To evaluate the safety and effectiveness of different dosages of intranasal Dexmedetomidine (DEX) in combination with oral midazolam for sedation of young children during brain MRI examination. METHODS: Included in this prospective single-blind randomized controlled trial were 156 children aged from 3 months to 6 years and weighing from 4 to 20 Kg with ASA I-II who underwent brain MRI examination between March 2021 and February 2022. Using the random number table method, they were divided into group A (using 3 ug/kg intranasal DEX plus 0.2 mg/Kg oral midazolam) and group B (using 2 ug/kg intranasal DEX plus 0.2 mg/Kg oral Midazolam). The one-time success rate of sedation, sedation onset time, recovery time, overall sedation time, and occurrence of adverse reactions during MRI examination were compared between the two groups. The heart rate (HR), mean arterial pressure (MAP), and percutaneous SpO2before and after drug administration were observed in both groups. Differences in sedation scores between the two groups were compared before intranasal drug administration (T0), 10 min after drug administration (T1), at the time of falling asleep (T2), at the end of examination (T3), and at the time of recovery (T4). RESULTS: The one-time success rate of sedation in group A and B was 88.31% and 79.75% respectively, showing no significant difference between the two groups (P>0.05). The sedation onset time in group A was 24.97±16.94 min versus 27.92±15.83 min in group B, and the recovery time was 61.88±22.18 min versus 61.16±28.16 min, both showing no significance difference between the two groups (P>0.05). Children in both groups exhibited good drug tolerance without presenting nausea and vomiting, hypoxia, or bradycardia and hypotension that needed clinical interventions. There was no significant difference in the occurrence of abnormal HR, MAP or other adverse reactions between the two groups (P>0.05). CONCLUSION: 3 ug/kg or 2 ug/kg intranasal DEX in combination with 0.2 mg/kg oral Midazolam both are safe and effective for sedation of children undergoing MRI examination with the advantages of fast-acting and easy application. TRIAL REGISTRATION: It was registered at the Chinese Clinical Trial Registry ( ChiCTR1800015038 ) on 02/03/2018.

Recent progress in synthesis, properties, and applications of hexagonal boron nitride-based heterostructures.

Featuring an absence of dangling bonds, large band gap, low dielectric constant, and excellent chemical inertness, atomically thin hexagonal boron nitride (h-BN) is considered an ideal candidate for integration with graphene and other 2D materials. During the past years, great efforts have been devoted to the research of h-BN-based heterostructures, from fundamental study to practical applications. In this review we summarize the recent progress in the synthesis, novel properties, and potential applications of h-BN-based heterostructures, especially the synthesis technique. Firstly, various approaches to the preparation of both in-plane and vertically stacked h-BN-based heterostructures are introduced in detail, including top-down strategies associated with exfoliation transfer processes and bottom-up strategies such as chemical vapor deposition (CVD)-based growth. Secondly, we discuss some novel properties arising in these heterostructures. Several promising applications in electronic and optoelectronic devices are also reviewed. Finally, we discuss the main challenges and possible research directions in this field.

Aligned Growth of Millimeter-Size Hexagonal Boron Nitride Single-Crystal Domains on Epitaxial Nickel Thin Film.

Atomically thin hexagonal boron nitride (h-BN) is gaining significant attention for many applications such as a dielectric layer or substrate for graphene-based devices. For these applications, synthesis of high-quality and large-area h-BN layers with few defects is strongly desirable. In this work, the aligned growth of millimeter-size single-crystal h-BN domains on epitaxial Ni (111)/sapphire substrates by ion beam sputtering deposition is demonstrated. Under the optimized growth conditions, single-crystal h-BN domains up to 0.6 mm in edge length are obtained, the largest reported to date. The formation of large-size h-BN domains results mainly from the reduced Ni-grain boundaries and the improved crystallinity of Ni film. Furthermore, the h-BN domains show well-aligned orientation and excellent dielectric properties. In addition, the sapphire substrates can be repeatedly used with almost no limit. This work provides an effective approach for synthesizing large-scale high-quality h-BN layers for electronic applications.

Potential risk assessment for safe driving of autonomous vehicles under occluded vision.

This study aimed to explore how autonomous vehicles can predict potential risks and efficiently pass through the dangerous interaction areas in the face of occluded scenes or limited visual scope. First, a Dynamic Bayesian Network based model for real-time assessment of potential risks is proposed, which enables autonomous vehicles to observe the surrounding risk factors, and infer and quantify the potential risks at the visually occluded areas. The risk distance coefficient is established to integrate the perception interaction ability of traffic participants into the model. Second, the predicted potential risk is applied to vehicle motion planning. The vehicle movement is improved by adjusting the speed and heading angle control. Finally, a dynamic simulation platform is built to verify the proposed model in two specific scenarios of view occlusion. The model has been compared with the existing methods, the autonomous vehicles can accurately assess the potential danger of the occluded areas in real-time and can safely, comfortably, and effectively pass through the dangerous interaction areas.

Quantum decision making in automatic driving.

The behavior intention estimation and interaction between Autonomous Vehicles (AV) and human traffic participants are the key problems in Automatic Driving System (ADS). When the classical decision theory studies implicitly assume that the behavior of human traffic participants is completely rational. However, according to the booming quantum decision theory in recent years and actual traffic cases, traffic behaviors and other human behaviors are often irrational and violate the assumptions of classical cognitive and decision theory. This paper explores the decision-making problem in the two-car game scene based on quantum decision theory and compares it with the current mainstream method of studying irrational behavior-Cumulative Prospect Theory (CPT) model. The comparative analysis proved that the Quantum Game Theory (QGT) model can explain the separation effect which the classical probability model can't reveal, and it has more advantages than CPT model in dealing with game scene decision-making. When two cars interact with each other, the QGT model can consider the interests of both sides from the perspective of the other car. Compared with the classical probability model and CPT model, the QGT is more realistic in the behavior decision-making of ADS.

Research on quantum cognition in autonomous driving.

Autonomous vehicles for the intention of human behavior of the estimated traffic participants and their interaction is the main problem in automatic driving system. Classical cognitive theory assumes that the behavior of human traffic participants is completely reasonable when studying estimation of intention and interaction. However, according to the quantum cognition and decision theory as well as practical traffic cases, human behavior including traffic behavior is often unreasonable, which violates classical cognition and decision theory. Based on the quantum cognitive theory, this paper studies the cognitive problem of pedestrian crossing. Through the case analysis, it is proved that the Quantum-like Bayesian (QLB) model can consider the reasonability of pedestrians when crossing the street compared with the classical probability model, being more consistent with the actual situation. The experiment of trajectory prediction proves that the QLB model can cover the edge events in interactive scenes compared with the data-driven Social-LSTM model, being more consistent with the real trajectory. This paper provides a new reference for the research on the cognitive problem of intention on bounded rational behavior of human traffic participants in autonomous driving.

Atomic Welded Dual-Wall Hollow Nanospheres for Three-in-One Hybrid Storage Mechanism of Alkali Metal Ion Batteries.

The rational design of hierarchical hollow nanomaterials is of critical significance in energy storage materials. Herein, dual-wall hollow nanospheres (DWHNS) Sn/MoS2@C are constructed by in situ confined growth and interface engineering. The inner hollow spheres of Sn/MoS2 are formed by atomic soldering MoS2 nanosheets with liquid Sn at high temperature. The formation mechanism of the hierarchical structure is explored by the morphology evolutions at different temperatures. The DWHNS Sn/MoS2@C manifest abundant inner space and high specific surface area, which provides more support sites for Li+/Na+/K+ storage and alleviates the volume effect of tin-based electrode materials to a certain extent. The composite material manifests an outstanding specific capacity and satisfactory reversibility of lithium ion batteries (∼931 mAh g-1 at 1 A g-1 after 500 cycles), sodium ion batteries (∼432 mAh g-1 at 1 A g-1 after 400 cycles), and potassium ion batteries (∼226 mAh g-1 at 1 A g-1 after 300 cycles). Additionally, the morphology evolution and mechanism analysis of DWHNS Sn/MoS2@C in alkali metal ion batteries are verified by ex situ measurement, which confirms the three-in-one hybrid storage mechanism, i.e., intercalation reaction of carbon shells, conversion reaction of MoS2, and alloying reaction of tin.

Remote heteroepitaxy of atomic layered hafnium disulfide on sapphire through hexagonal boron nitride.

Two-dimensional (2D) heterostructures have attracted a great deal of attention due to their novel phenomena arising from the complementary properties of their constituent materials, and provide an ideal platform for exploring new fundamental research and realizing technological innovation. Here, for the first time, we report the formation of high quality HfS2/h-BN heterostructures by the remote heteroepitaxy technique, in which the large-area single-crystal HfS2 layers were epitaxially grown on c-plane sapphire through a polycrystalline h-BN layer via chemical vapor deposition. It is found that c-sapphire substrates can penetrate monolayer and bilayer h-BN to remotely handle the epitaxial growth of HfS2. Benefitting from the high crystal quality of HfS2 epilayers and the weak interface scattering of HfS2 on h-BN, the HfS2 photodetectors demonstrate excellent performance with a high on/off ratio exceeding 105, an excellent photoresponsivity up to 0.135 A W-1 and a high detectivity of over 1012 Jones. Furthermore, the HfS2/h-BN heterostructures prepared by the remote epitaxy can be rapidly released and transferred to a substrate of interest, which opens a new pathway for large-area advanced wearable electronics applications.

Compositional Engineering of Mixed-Cation Lead Mixed-Halide Perovskites for High-Performance Photodetectors.

The mixed-cation lead mixed-halide perovskites can combine the advantages of the constituents while avoiding their drawbacks, and they have been widely explored in solar cells. However, there are only few research studies on the mixed-cation lead mixed-halide perovskites for photodetectors. In this work, we fabricate photodetectors based on FA(1-x)CsxPb(BryI(1-y))3 perovskite and reveal the effect of the chemical composition on the crystal phase stability and device performance of mixed-cation mixed-halide perovskite photodetectors. The FA0.7Cs0.3Pb(I0.8Br0.2)3 photodetectors exhibit high specific detectivity, high responsivity, and excellent stability in ambient conditions. Especially, the flexible perovskite photodetectors fabricated on poly(ethylene terephthalate) substrates exhibit extremely high specific detectivity of 2.8 × 1013 Jones, which is the highest value to date for flexible perovskite photodetectors, as well as excellent stability and outstanding flexibility. These results indicate that mixed-cation mixed-halide perovskites are promising to be applied in high-performance photodetectors and other flexible optoelectronic devices.

Two-dimensional hexagonal boron-carbon-nitrogen atomic layers.

Two-dimensional (2D) hexagonal boron-carbon-nitrogen (h-BCN) atomic layers are expected to possess interesting properties complementary to those of graphene and h-BN, enabling a rich variety of electronic structures, properties and applications. Herein, we demonstrate a novel method to synthesize 2D h-BCN atomic layers with a full range of compositions by ion beam sputtering deposition under a mixed Ar/CH4 atmosphere. The h-BCN layers have been thoroughly characterized by various techniques, aiming at the determination of their structure evolution and properties. We find that homogeneous h-BCN layers consisting of graphene and h-BN nanodomains can be obtained at an appropriate C content, whereas too high or too low C contents result in the segregation of large-sized graphene or h-BN islands. Furthermore, the band gap of h-BCN layers slightly decreases with the increasing C content, while their electric properties can be tuned from insulating to highly conducting. This work provides a novel approach for synthesizing 2D h-BCN atomic layers and paves the way for the development of h-BCN-based devices.

Interface Engineering of High-Performance Perovskite Photodetectors Based on PVP/SnO2 Electron Transport Layer.

Hybrid organic-inorganic perovskites have attracted intensive interest as active materials for high-performance photodetectors. However, studies on the electron transport layer (ETL) and its influence on the response time of photodetectors remain limited. Herein, we compare the performances of perovskite photodetectors with TiO2 and SnO2 ETLs, especially on the response time. Both photodetectors exhibit a high on/off current ratio of 105, a large detectivity around 1012 Jones, and a linear dynamic range over 80 dB. The SnO2-based perovskite photodiodes show ultrahigh response rates of 3 and 6 µs for the rise and decay times, respectively. However, photodetectors with TiO2 ETLs have low responsivity and long response time at low driving voltage, which is attributed to the electron extraction barrier at the TiO2/perovskite interface and the charge traps in the TiO2 layer. Furthermore, the dark current of SnO2-based perovskite photodiodes is effectively suppressed by inserting a poly(vinylpyrrolidone) interlayer, and then the on/off current ratio increases to 1.2 × 106, corresponding to an improvement of 1 order of magnitude. Such low-cost, solution-processable perovskite photodetectors with high performance show promising potential for future optoelectronic applications.

High-performance deep ultraviolet photodetectors based on few-layer hexagonal boron nitride.

Hexagonal boron nitride (h-BN), an isomorph of graphene, has attracted great attention owing to its potential applications as an ultra-flat substrate or gate dielectric layer in novel graphene-based devices. Besides, h-BN appears to be a promising material for deep ultraviolet (DUV) optoelectronic applications because of its extraordinary physical properties, such as wide band gap and high absorption coefficient. In this work, two-dimensional h-BN with controllable layers was synthesized on Cu foils by ion beam sputtering deposition, and DUV photodetectors were fabricated from the transferred h-BN layers on SiO2/Si substrates. The h-BN layers synthesized at the higher substrate temperature possess a lower density of domain boundaries and higher crystalline quality, and the photodetectors based on a 3 nm h-BN layer exhibited high performance with an on/off ratio of >103 under DUV light illumination at 212 nm and a cutoff wavelength at around 225 nm. This work demonstrates that two-dimensional h-BN layers are promising for the construction of high-performance solar-blind photodetectors.

Large-Area Synthesis of Layered HfS2(1- x )Se2 x Alloys with Fully Tunable Chemical Compositions and Bandgaps.

Alloying transition metal dichalcogenides (TMDs) with different compositions is demonstrated as an effective way to acquire 2D semiconductors with widely tunable bandgaps. Herein, for the first time, the large-area synthesis of layered HfS2(1- x )Se2 x alloys with fully tunable chemical compositions on sapphire by chemical vapor deposition is reported, greatly expanding and enriching the family of 2D TMDs semiconductors. The configuration and high quality of their crystal structure are confirmed by various characterization techniques, and the bandgap of these alloys can be continually modulated from 2.64 to 1.94 eV with composition variations. Furthermore, prototype HfS2(1- x )Se2 x photodetectors with different Se compositions are fabricated, and the HfSe2 photodetector manifests the best performance among all the tested HfS2(1- x )Se2 x devices. Remarkably, by introducing a hexagonal boron nitride layer, the performance of the HfSe2 photodetector is greatly improved, exhibiting a high on/off ratio exceeding 105, an ultrafast response time of about 190 µs, and a high detectivity of 1012 Jones. This simple and controllable approach opens up a new way to produce high-quality 2D HfS2(1- x )Se2 x layers, which are highly qualified candidates for the next-generation application in high-performance optoelectronics.