Synthesis and characterization of potential polycyclic energetic materials using bicyclic triazole and azetidine structures as building blocks.

Exploring the design strategy of new energetic materials is crucial to promote the development of energetic materials. In this study, a method for designing polycyclic energetic materials is proposed by combining the azetidine structure with azobis-1,2,4-triazole or bi-1,2,4-triazole. A series of typical triazolyl polycyclic compounds were designed and synthesized by simple nucleophilic reaction, which included 5,5'-dichloro-3,3'-bis(3,3'-difluoroazetidine)-4,4'-azobis-1,2,4-triazole (1), 5,5'-dichloro-3,3'-bis(3,3'-difluoroazetidine)-4,4'-bi-1,2,4-triazole (2), 5,5'-dichloro-3-(N,N-dimethyl)-3'-(3,3'-difluoroazetidine)-4,4'-bi-1,2,4-triazole (3) 5,5'-dichloro-3,3'-bis(3,3'-dinitroazetidine)-4,4'-bi-1,2,4-triazole (4), 5,5'-dichloro-3-(N,N-dimethyl)-3'-(3,3'-dinitroazetidine)-4,4'-bi-1,2,4-triazole (5), and 5,5'-diazido-3,3'-bis(3,3'-difluoroazetidine)-4,4'-azo-1,2,4-triazole (6). These designed and synthesized polycyclic compounds (1, 2, 3) have high decomposition temperatures (>200 °C). The molecular van der Waals surface electrostatic potentials suggested the reactivity of compounds 1, 2, and 3 when attacked by nucleophiles. The natural bond orbital and Hirshfeld surface analysis proved the essential reason for the stability of these compounds in theory. The formula design example suggests that some triazolyl polycyclic compounds (4, 5, and 6) are potentially explosives, suggesting that this strategy is feasible for constructing the triazolyl polycyclic energetic compounds.

Atmospheric oxidizing capacity in autumn Beijing: Analysis of the O3 and PM2.5 episodes based on observation-based model.

Atmospheric oxidizing capacity (AOC) is the fundamental driving factors of chemistry process (e.g., the formation of ozone (O3) and secondary organic aerosols (SOA)) in the troposphere. However, accurate quantification of AOC still remains uncertainty. In this study, a comprehensive field campaign was conducted during autumn 2019 in downtown of Beijing, where O3 and PM2.5 episodes had been experienced successively. The observation-based model (OBM) is used to quantify the AOC at O3 and PM2.5 episodes. The strong intensity of AOC is found at O3 and PM2.5 episodes, and hydroxyl radical (OH) is the dominating daytime oxidant for both episodes. The photolysis of O3 is main source of OH at O3 episode; the photolysis of nitrous acid (HONO) and formaldehyde (HCHO) plays important role in OH formation at PM2.5 episode. The radicals loss routines vary according to precursor pollutants, resulting in different types of air pollution. O3 budgets and sensitivity analysis indicates that O3 production is transition regime (both VOC and NOx-limited) at O3 episode. The heterogeneous reaction of hydroperoxy radicals (HO2) on aerosol surfaces has significant influence on OH and O3 production rates. The HO2 uptake coefficient (γHO2) is the determining factor and required accurate measurement in real atmospheric environment. Our findings could provide the important bases for coordinated control of PM2.5 and O3 pollution.

[Reoperation treatment of persistent postoperative secondary hyperparathyroidism].

Objective:To evaluate the clinical effect of reoperation in persistent hyperparathyroidism （PHPT） patients after operation of parathyroidectomy combined with autotransplantation（PTX+AT） on secondary hyperparathyroidism （SHPT） . Methods:18 PHPT patients who treated with reoperation after PTX+AT were enrolled in this study during the period from Aug 2012 to Dec 2021 in the Department of Otolaryngology Head and Neck Surgery of Peking University Civil Aviation School of Clinical Medicine, Civil Aviation General Hospital. The remaining parathyroid glands were located by preoperative colour Doppler ultrasonography, radionuclide imaging, enhanced CT and MR imaging in the neck region . Based on the imaging findings, the remaining parathyroid glands were removed in situ, and the missed ectopic or extra parathyroid glands were resected with an extended surgical scope according to the parathyroid dissection method. The surgical effect was evaluated by the changes of clinical symptoms, the dynamic change of serum intact paramyroidhomone（i-PTH） between preoperative and postoperative periods and the surgical complications. Results:All the 18 patients accepted successful operation. 30 parathyroid glands were resected confirmed by postoperative pathology, including 16 in situ and 14 ectopic glands（5 in superior mediastinum, 4 in thymus, 2 in posterior mediastinum ,2 in thyroid glands, 1 in carotid sheath）.Osteoarthropathy and skin itching were significantly relieved or even disappeared at 6 h after surgery. The levels of serum i-PTH, calcium and phosphorus reached the standards and muscle weakness was significantly improved 1 week after surgery. 16 patients presented hypocalcemia and returned to normal after supplement of calcium. Hoarseness due to temporary injury of laryngeal nerve was found in 6 cases. No serious complications or death occurred after the operation.There was no recurrence after 1 year follow-up. Conclusion:Reoperation is the first choice for SHPT patients complicated with persistent hyperparathyroidism. Multiple imaging examinations are used to locate the residual parathyroid, especially the ectopic gland. Expanded surgical scope is applied to resect all the residual parathyroid glands（ectopic, in situ and concealed parathyroid） according to the concept of dissection parathyroidectomy. The surgery is effective and safe. Patients'quality of life and long-term survival rate is improved.

A Structural Design Method of 3D Electromagnetic Wave-Absorbing Woven Fabrics.

Based on the wave absorption model of 3D woven fabric and the zero-reflection equations, a new structural design method of 3D electromagnetic (EM) wave-absorbing woven fabrics was obtained. The 3D woven fabrics fabricated by the proposed method had the structure of a bidirectional angle interlock. Continuous S-2 glass fibers were used as the matching layer of this 3D woven fabric, and continuous carbon fibers were used as the absorbing layer. The absorbing layer satisfied the equivalent EM parameters under the condition of zero reflection. The results of the simulation and experiment showed that the performance trends of the 3D wave-absorbing fabric obtained by this method were consistent with the theory, which verified the correctness of the structure design method. The 3D fabrics obtained by this method have the advantages of wide absorbing frequencies and good absorbing performance (-20 dB). This structural design method also has theoretical guiding significance for the development of 3D wave-absorbing fabrics.

Formation mechanisms of nitrous acid (HONO) during the haze and non-haze periods in Beijing, China.

As an important precursor of hydroxyl radical (OH), nitrous acid (HONO) plays a significant role in atmospheric chemistry. Here, an observation of HONO and relevant air pollutants in an urban site of Beijing from 14 to 28 April, 2017 was performed. Two distinct peaks of HONO concentrations occurred during the observation. In contrast, the concentration of particulate matter in the first period (period Ⅰ) was significantly higher than that in the second period (period Ⅱ). Comparing to HONO sources in the two periods, we found that the direct vehicle emission was an essential source of the ambient HONO during both periods at night, especially in period Ⅱ. The heterogeneous reaction of NO2 was the dominant source in period Ⅰ, while the homogeneous reaction of NO with OH was more critical source at night in period Ⅱ. In the daytime, the heterogeneous reaction of NO2 was a significant source and was confirmed by the good correlation coefficients (R2) between the unknown sources (Punknown) with NO2, PM2.5, NO2 × PM2.5 in period Ⅰ. Moreover, when solar radiation and OH radicals were considered to explore unknown sources in the daytime, the enhanced correlation of Punknown with photolysis rate of NO2 and OH ( [Formula: see text]  × OH) were 0.93 in period Ⅰ, 0.95 in period Ⅱ. These excellent correlation coefficients suggested that the unknown sources released HONO highly related to the solar radiation and the variation of OH radicals.

Sources of ambient non-methane hydrocarbon compounds and their impacts on O3 formation during autumn, Beijing.

The field observation of 54 non-methane hydrocarbon compounds (NMHCs) was conducted from September 1 to October 20 in 2020 during autumn in Haidian District, Beijing. The mean concentration of total NMHCs was 29.81 ± 11.39 ppbv during this period, and alkanes were the major components. There were typical festival effects of NMHCs with lower concentration during the National Day. Alkenes and aromatics were the dominant groups in ozone formation potential (OFP) and OH radical loss rate (LOH). The positive matrix factorization (PMF) running results revealed that vehicular exhaust became the biggest source in urban areas, followed by liquefied petroleum gas (LPG) usage, solvent usage, and fuel evaporation. The box model coupled with master chemical mechanism (MCM) was applied to study the impacts of different NMHCs sources on ozone (O3) formation in an O3 episode. The simulation results indicated that reducing NMHCs concentration could effectively suppress O3 formation. Moreover, reducing traffic-related emissions of NMHCs was an effective way to control O3 pollution at an urban site in Beijing.

Effect of Different Combustion Processes on Atmospheric Nitrous Acid Formation Mechanisms: A Winter Comparative Observation in Urban, Suburban and Rural Areas of the North China Plain.

Atmospheric nitrous acid (HONO) is a dominant precursor of hydroxyl (OH) radicals, and its formation mechanisms are still controversial. Few studies have simultaneously explored effects of different combustion processes on HONO sources. Hereby, synchronous HONO measurement in urban (BJ), suburban (XH) and rural (DBT) areas with different combustion processes is performed in the North China Plain in winter. A box model is utilized to analyze HONO formation mechanisms. HONO concentration is the highest at the DBT site (2.51 ± 1.90 ppb), followed by the XH (2.18 ± 1.95 ppb) and BJ (1.17 ± 1.20 ppb) sites. Vehicle exhaust and coal combustion significantly contribute to nocturnal HONO at urban and rural sites, respectively. During a stagnant pollution period, the NO+OH reaction and combustion emissions are more crucial to HONO in urban and rural areas; meanwhile, the heterogeneous reaction of NO2 is more significant in suburban areas. Moreover, the production rate of OH from HONO photolysis is about 2 orders of magnitude higher than that from ozone photolysis. Consequently, vehicle exhaust and coal combustion can effectively emit HONO, further causing environmental pollution and health risks. It is necessary to expand the implementation of the clean energy transition policy in China, especially in areas with substantial coal combustion.

A Review of Electromagnetic Shielding Fabric, Wave-Absorbing Fabric and Wave-Transparent Fabric.

As the basic materials with specific properties, fabrics have been widely applied in electromagnetic (EM) wave protection and control due to their characteristics of low density, excellent mechanical properties as well as designability. According to the different mechanisms and application scenarios on EM waves, fabrics can be divided into three types: EM shielding fabric, wave-absorbing fabric and wave-transparent fabric, which have been summarized and prospected from the aspects of mechanisms and research status, and it is believed that the current research on EM wave fabrics are imperfect in theory. Therefore, in order to meet the needs of different EM properties and application conditions, the structure of fabrics will be diversified, and more and more attentions should be paid to the research on structure of fabrics that meets EM properties, which will be conductive to guiding the development and optimization of fabrics. Furthermore, the application of fabrics in EM waves will change from 2D to 3D, from single structure to multiple structures, from large to small, as well as from heavy to light.

Comparative observation of atmospheric nitrous acid (HONO) in Xi'an and Xianyang located in the GuanZhong basin of western China.

HONO is an important component of reactive nitrogen (Nr) and precursors of OH radical. However, the source and removal of HONO are not clear. Here, measurements of HONO (May 18-31, 2018) were conducted in Xi'an and Xianyang simultaneously for the first time. The relationship between HONO and other Nr (such as NO and NO2) in two cities was analyzed. The mixing ratio of HONO in Xi'an was 1.2 ± 0.8 ppbv, and that in Xianyang was 1.2 ± 1.1 ppbv. The nighttime HONO mixing ratio was higher in Xianyang, while the daytime HONO was higher in Xi'an. Compared with the contribution from heterogeneous process of NO2, direct emissions and homogeneous processes (NO + OH) were less important for nocturnal HONO formation in these two cities. The relative contribution of heterogeneous process in Xianyang was more important than that in Xi'an. The reaction of NO2 upon aerosols surface was identified as an important source of HONO for two sites. The conversion of NO2 on the other surfaces might attend the heterogeneous formation of HONO in Xianyang site. Daytime HONO budget analysis indicated that there was an additional unknown formation process of HONO at two sites. The net OH production rate from HONO (from 08:00 to 17:00) was 1.6 × 107 and 1.3 × 107 molecule/(cm3 s) for Xian and Xianyang, 5.2 and 3.5 times higher than from O3 photolysis. Besides, a dust storm appeared during this observation period, and the impact of local emission and transport processes was separately analyzed. The sources, characteristics, and effects of HONO identified in this study laid a foundation for further research on HONO and air pollution in the Guanzhong area.

Different HONO Sources for Three Layers at the Urban Area of Beijing.

Gaseous nitrous acid (HONO) is a crucial precursor of the hydroxyl (OH) radical, which is a "detergent" in the atmosphere. Nowadays, HONO formation mechanisms at polluted urban areas are controversial, which restricts the understanding of atmospheric oxidative capacity and radical cycling. Herein, multiday vertical observation of HONO and NOx was simultaneously performed at three heights at the urban area of Beijing for the first time. The vertical distribution of HONO was often unexpected, and it had the highest HONO concentration at 120 m, followed by those at 8 and 240 m. 0D box model simulations suggest that ground and aerosol surfaces might play similar roles in NO2 conversion at 8 m during the whole measurement. NO2 conversion on aerosol surfaces was the most important HONO source aloft during haze days. At daytime, a strong missing HONO source unexpectedly existed in the urban aloft, and it was relevant to solar radiation and consumed OH.

Pollution characteristics and potential sources of nitrous acid (HONO) in early autumn 2018 of Beijing.

Nitrous Acid (HONO) is an important precursor of hydroxyl radical (OH) and has significant impacts on the formation of Ozone (O3) and Secondary Organic Aerosol (SOA). The atmospheric concentrations of HONO were measured during early autumn in downtown, Beijing (China). This study investigated HONO pollution characteristics and potential sources during day and night. The maximum hourly HONO levels reached 5.16 ppb, with 1.23 ppb on average. HONO concentration exhibited typical diurnal variation characteristics, with maximum at nighttime and minimum at daytime. The potential sources mainly included vehicle emission, heterogeneous reaction of NO2 on aerosol surfaces (Photo-enhanced at the daytime) and photolysis of particulate nitrate (NO3-) in Beijing. Vehicle emission was an important HONO source, particular at the morning rush period and lower HONO concentration. The simulated results highlighted that the main contribution of HONO was NO2 heterogeneous reaction on aerosol surfaces. The photolysis of particulate NO3- was also an important daytime HONO source, particularly in the pollution period. The main loss routine was the photolysis of HONO and dry deposition at day and night, respectively.

Tagged sources of short-chain chlorinated paraffins in China's marine environment and fish.

Most emitters of short chain chlorinated paraffins (SCCPs) in China are located in eastern China, posing potential risks to the marine environment and food web. Here we employed a comprehensive atmospheric transport model combined with multiple environmental compartment exchange modules and a marine food web model to simulate levels and risks of SCCPs in the marine environment and fish in the Yellow Sea (YS), East China Sea (ECS), and South China Sea (SCS). Results unveiled a decreasing SCCP level in seawaters and sediments towards offshore. The modeled SCCP total (dry + wet) loadings to the three seawater bodies ranged from 0.0013 to 0.1635 mg/m2/season and gaseous diffusive deposition ranged from 43 to 4443 kg/month. The meteorological factors and secondary emission contributing to seasonal changes in SCCPs were also discussed. A tagging technique was used to trace origins of SCCPs, demonstrating that source proximity contributes most in SCCP contamination to these seawater bodies. Modeled SCCP levels in 5 marine fish in the YS, ECS, and SCS ranged from 23 to 111 ng/g. Our results showed the current SCCP levels in the marine environment and fish did not pose exposure risks to fish consumers for different age groups and genders. However, if consumed fish were harvested and imported from more seriously contaminated seawaters by SCCPs, the estimated dietary intake (EDI) would considerably increase.

Spatiotemporal variation of atmospheric nitrated polycyclic aromatic hydrocarbons in semi-arid and petrochemical industrialized Lanzhou City, Northwest China.

Polyurethane foam-based passive air sampler (PUF-PAS) and passive dry deposition sampler (PAS-DD) were adopted, for the first time ever in China, to investigate the atmospheric levels and spatial-temporal distributions of air burdens and dry deposition fluxes of 12 nitrated polycyclic aromatic hydrocarbons (NPAHs) during winter and summer seasons in a multiple site field campaign in a petrochemical industrialized capital city in Northwest China. The results showed that the highest air concentration and dry deposition fluxes of ∑12NPAHs occurred at a heavy traffic site among 18 sampling sites in both winter and summer season. The lowest air concentration and dry deposition fluxes were observed at the background site. The mean concentrations of ∑12NPAHs in the ambient air were 8.6 ± 8.1 ng m-3 in winter and 15 ± 11 ng m-3 in summer. The mean dry deposition fluxes of ∑12NPAHs were 1.8 × 103 ± 1.9 × 103 ng (m2 day)-1 in winter and 1.4 × 103 ± 1.3 × 103 ng (m2 day)-1 in summer, respectively. The total concentration of 12 NPAHs was mainly dominated by 1-nitro-naphthalene (1N-NAP) and 2-nitro-naphthalene(2N-NAP) in air, accounting for 32% in winter and 45% in summer of ∑12NPAHs. 7-Nitro-benzo [a] anthracene (7N-BaA) made the largest contribution to dry deposition fluxes of ∑12NPAHs, accounting for 28% in winter and 24% in summer. The ratios of ∑12NPAHs/∑15pPAHs (parent polycyclic aromatic hydrocarbons) were calculated to identify potential sources of NPAHs across the city. The results revealed that the main atmospheric air concentration and dry deposition fluxes of 12 NPAHs could be attributed to the primary emissions in winter and the secondary reaction formation in summer. The sources of primary emissions could be traced back to petrochemical, steel mills, as well as aluminum industries in winter and vehicle exhaust in summer. Higher ∑12NPAH/∑15pPAH concentration ratios in summer indicated that the oxidation of pPAHs contributed to the secondary formation of NPAHs via atmospheric chemical reactions in this petrochemical industrialized mountain-valley city.

Thermogravimetric analysis, kinetic study, and pyrolysis-GC/MS analysis of 1,1'-azobis-1,2,3-triazole and 4,4'-azobis-1,2,4-triazole.

BACKGROUND: In general, the greater the number of directly linked nitrogen atoms in a molecule, the better its energetic performance, while the stability will be accordingly lower. But 1,1'-azobis-1,2,3-triazole (1) and 4,4'-azobis-1,2,4-triazole (2) show remarkable properties, such as high enthalpies of formation, high melting points, and relatively high stabilities. In order to rationalize this unexpected behavior of the two compounds, it is necessary to study their thermal decompositions and pyrolyses. Although a great deal of research has been focused on the synthesis and characterization of energetic materials with 1 and 2 as the backbone, a complete report on their fundamental thermodynamic parameters and thermal decomposition properties has not been published. METHODS: Thermogravimetric-differential scanning calorimetry were used to obtain the thermal decomposition data of the title compounds. Kissinger and Ozawa-Doyle methods, the two selected non-isothermal methods, are presented for analysis of the solid-state kinetic data. Pyrolysis-gas chromatography/mass spectrometry was used to study the pyrolysis process of the title compounds. RESULTS: The DSC curves show that the thermal decompositions of 1 and 2 are at different heating rates involved a single exothermic process. The TG curves provide insight into the total weight losses from the compounds associated with this process. At different pyrolysis temperatures, the compositions and types of the pyrolysis products differ greatly and the pyrolysis reaction at 500 °C is more thorough than 400 °C. CONCLUSIONS: Apparent activation energies (E) and pre-exponential factors (lnA/s-1) are 291.4 kJ mol-1 and 75.53 for 1; 396.2 kJ mol-1 and 80.98 for 2 (Kissinger). The values of E are 284.5 kJ mol-1 for 1 and 386.1 kJ mol-1 for 2 (Ozawa-Doyle). The critical temperature of thermal explosion (T b ) is evaluated as 187.01 °C for 1 and 282.78 °C for 2. The title compounds were broken into small fragment ions under the pyrolysis conditions, which then might undergo a multitude of collisions and numerous other reactions, resulting in the formation of C2N2 (m/z 52), etc., before being analyzed by the GC/MS system.

Contamination of short-chain chlorinated paraffins to the biotic and abiotic environments in the Bohai Sea.

Short-chain chlorinated paraffins (SCCPs) have been produced and emitted intensively around the Bohai Sea, potentially causing risks to this unique ecosystem and one of primary fishery resources in China and busiest seaways in the world. Little is known about fate, cycling, and sources of SCCPs in the Bohai Sea biotic and abiotic environment. In this study, we combined a marine food web model with a comprehensive atmospheric transport-multiple phase exchange model to quantify SCCPs in the biotic and abiotic environment in the Bohai Sea. We performed multiple modeling scenario investigations to examine SCCP levels in water, sediment, and phytoplankton. We assessed numerically dry and wet depositions, biomagnification and bioaccumulation of SCCPs in the Bohai Sea marine food web. Results showed declining SCCP levels in water and sediment with increasing distance from the coastline, and so do dry and wet depositions. The net deposition overwhelmed the water-air exchange of SCCPs due to their current use in China, though the diffusive gas deposition fluctuated monthly subject to mean wind speed and temperature. A risk assessment manifests that SCCPs levels in the Bohai Sea fish species are at present not posing risks to the residents in the Bohai Sea Rim region. We identified that the SCCP emission sources in the south of the Bohai Sea made a primary contribution to its loadings to the seawater and fish contamination associated with the East Asian summer monsoon. In contrast, the SCCP emissions from the north and northwest regions of the Bohai Sea were major sources contributing to their loading and contamination to Bohai Sea food web during the wintertime, potentially driven by the East Asian winter monsoon.

Gridded emission inventory of short-chain chlorinated paraffins and its validation in China.

China produces approximately 20%-30% of the total global chlorinated paraffins (CPs). The establishment of a short-chain CP (SCCP) emission inventory is a significant step toward risk assessment and regulation of SCCPs in China and throughout the globe. This study developed a gridded SCCPs emission inventory with a 1/4° longitude by 1/4° latitude resolution from 2008 to 2012 for China, which was based on the total annual CPs emissions for the nation. The total national SCCPs emission during this 5-year period was 5651.5 tons. An additive in metal cutting fluids was a major emission source in China, contributing 2680.2 tons to the total atmospheric emissions of SCCPs from 2008 to 2012, followed by the production of CPs (2281.8 tons), plasticizers (514.3 tons), flame retardants (108.6 tons), and net import (66.6 tons). Most of these emission sources are located along the eastern seaboard of China and southern China. A coupled atmospheric transport model was employed to simulate environmental contamination by SCCPs using the gridded emission inventory of SCCPs from 2008 to 2012 as the model initial conditions. Simulated atmospheric and soil concentrations were compared with field monitoring data to validate the emission inventory. The results showed good consistency between modeled and field sampling data, supporting the reliability and credibility of the gridded SCCPs emission inventory that was developed in the present study.

Chemical characterization and source apportionment of PM2.5 in a semi-arid and petrochemical-industrialized city, Northwest China.

Daily PM2.5 samples were collected in 2014 at a suburban petrochemical industrial site and a downtown site in Lanzhou city, Northwest China. Major chemical components in PM2.5, including water-soluble ions, metal elements, and organic and elemental carbon (OC and EC) were determined. The chemical mass closure method and the ISORROPIA II thermodynamic equilibrium model were used to reconstruct PM2.5 mass and quantify the combinations of NH4+, SO42- and NO3- to PM2.5. Positive matrix factorization (PMF) model was employed to apportion potential sources of PM2.5. The annual average PM2.5 concentration was 93.7±49.6µgm-3 at the suburban petrochemical industrial site and 88.9±52.0µgm-3 at the urban site, with the highest seasonal average in winter and the lowest in summer at both sites. Mineral dust was identified as the highest contributor to PM2.5 in spring, while water-soluble inorganic ions and carbonaceous aerosols were the dominant chemical components in other seasons. The correlation relationships between OC and EC and between K+ and EC suggested that coal combustion and vehicle exhaust were the major sources of carbonaceous aerosols in Lanzhou. Six major sources were identified by the PMF model. Coal combustion, soil dust, traffic emissions, and secondary inorganic aerosols were the dominant contributors, together accounting for 82% of PM2.5 mass.

The estimation of neurotransmitter release probability in feedforward neuronal network based on adaptive synchronization.

In this paper, we proposed a new approach to estimate unknown parameters and topology of a neuronal network based on the adaptive synchronization control scheme. A virtual neuronal network is constructed as an observer to track the membrane potential of the corresponding neurons in the original network. When they achieve synchronization, the unknown parameters and topology of the original network are obtained. The method is applied to estimate the real-time status of the connection in the feedforward network and the neurotransmitter release probability of unreliable synapses is obtained by statistic computation. Numerical simulations are also performed to demonstrate the effectiveness of the proposed adaptive controller. The obtained results may have important implications in system identification in neural science.

[Influence of acupuncture of Zusanli (ST 36) on connectivity of brain functional network in healthy subjects].

OBJECTIVE: To observe the effect of acupuncture of Zusanli (ST 36) on electroencephalogram (EEG) so as to probe into its law in regulating the interconnectivity of brain functional network. METHODS: A total of 9 healthy young volunteer students (6 male, 3 female) participated in the present study. They were asked to take a dorsal position on a test-bed. EEG signals were acquired from 22 surface scalp electrodes (Fp1, Fp2, F7, F3, F2, F4, F8, A1, T3, C3, C2, C4, T4, A2, T5, P3, P2, P4, T6, O2, O1 and O2) fixed on the subject's head. Acupuncture stimulation was applied to the right Zusanli (ST 36) by manipulating the filiform needle with uniform reducing-reinforcing method and at a frequency of about 50 cycles/min for 2 min. Then the stimulation was stopped for 10 min, and repeated once again (needle-twirling frequency: 150 and 200 cycles/min), 3 times altogether. The acquired EEG data were analyzed by using coherence estimation method, average path length, average clustering coefficient, and the average degree of the articulation points (nodes) for analyzing the synchronization of EEG signals before, during and after acupuncture. RESULTS: In comparison with pre-acupuncture, the coherence amplitude values of EEG-delta (1-4 Hz) and y (31-47 Hz) waves were increased significantly after acupuncture of ST 36. No significant changes were found in the amplitude values of EEG-theta (5-8 Hz), -alpha (9-13 Hz) and-beta (14-30 Hz) waves after acupuncture stimulation. During and after acupuncture, the synchronism values of EEG-delta waves of different leads and numbers of interconnectivity between every two brain functional regions in majority of the 9 volunteers were increased clearly. In all volunteers, the degree values of all nodes except A1 and A2, the average clustering coefficients along with the increase of the threshold (r), and the average path lengths of the brain functional network of EEG-delta waves during and after acupuncture were also increased evidently (the latter two items, P < 0.05), suggesting an increase of the information exchange and functional connectivity of different brain regions. CONCLUSION: Acupuncture of Zusanli (ST 36) can increase the amplitude and synchronization of EEG-delta waves of different leads, and potentiate the functional interconnectivity of brain functional network.

Estimating and adjusting abnormal networks with unknown parameters and topology.

The changes of parameters and topology in a complex network often lead to unexpected accidents in complex systems, such as diseases in neural systems and unexpected current in circuit system, so the methods of adjusting the abnormal network back to its normal conditions are necessary to avoid these problems. However, it is not easy to detect the structures and information of each network, even if we can find a network which has the same function as the abnormal network, it is still hard to use it as a reference to adjust the abnormal network because a lot of network information is unknown. In this paper, we design a "bridging network" as an information bridge between a normal network and an abnormal network to estimate and control the abnormal network. Through the "bridging network" and some adaptive laws, the abnormal parameters and connections in abnormal network can be adjusted to the same conditions as those of the normal network which is chosen as a reference model. Finally, the "bridging network" and the abnormal network achieve synchronization with the normal network. Besides, the detailed inner information in normal network and abnormal network can be accurately estimated by this "bridging network." Finally, the nodes in the abnormal network will behave normally after the correction. In this paper, we use Hindmarsh-Rose model as an example to describe our method.