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Micrometer-sized spherical composites based on 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (CL-20) with fluororubber (F2604), dioctyl sebacate (DOS), and polyvinyl butyral (PVB) were prepared by an electrospray method. After preparation, the morphology, chemical bonds, thermal decomposition properties, mechanical sensitivity, and explosion performance were characterized. The main explosive CL-20 transformed from ε-CL-20 to β-CL-20 after electrospray preparation. With an insensitive additive mass ratio of 5 wt %, the CL-20/F2604 composite had the highest maximum peak exothermic temperature and the lowest mechanical sensitivity. The explosion pressures of the composites with the same mass ratio of additives decreased in the order CL-20/F2604CL-20/PVBCL-20/DOS and were lower than that of raw CL-20.

In a constant-volume chamber, the atomization characteristics of low-viscosity fuel sprays were studied under the effects of mass concentration and injection pressure. Microscopic spray parameters were measured via laser diffraction downstream of the nozzle at various axial and radial positions. The results showed that an increase in the mass concentration suppressed the atomization effect in a linear manner. The increase in injection pressure promoted droplet breakup; however, the trend gradually weakened and became more noticeable at high concentrations. Compared to the concentration, the influence of the injection pressure on the atomization characteristics was dominant. Although low concentration and high injection pressure promoted droplet breakup, they also increased the probability of droplet collision, resulting in droplet aggregation. This was more evident in low-viscosity fuels. The droplet size increased in the axial direction owing to the aggregation. However, the diameter decreased in the radial direction owing to the outward deflection of small droplets caused by air turbulence and entrainment. In addition, the high-velocity airflow significantly promoted droplet breakup near the nozzle and spray axis regions and suppressed the aggregation effect. Nevertheless, lower-viscosity fuels maintained smaller droplet sizes and better atomization throughout the spraying process, which was easier to achieve than that in higher-viscosity fuels. Overall, low concentration, high injection pressure and low viscosity of the fuel have beneficial effects on the droplet breakup. This is important to enhance the atomization effect of the fuel.

Among all the CL-20/HMX-based energetic composites, CL-20/HMX/PVAc sample 1 possesses the highest maximum burn pressure value of 33.3 kPa.

Background To explore the clinical efficacy and safety of Kirschner wires (KW) as blocking screws technique in extra-articular fractures of the distal tibia treated with intramedullary nail (IMN). Methods 61 patients treated with IMN for extra-articular fractures of the distal tibia assisted with KW as blocking screws technique or Poller screws (PS) technique. The operation time, times of fluoroscopy, number of blocking screws used, blood loss and time to union were compared between the two groups. Also, the functional outcomes of the two groups were compared using range of motion (ROM), visual analogue scale (VAS), American Orthopedic Foot and Ankle Society (AOFAS), and Lysholm scores. Results Compared with the PS group, the operation time of the KW group was significantly shorter, the times of fluoroscopy and the amount of blood loss during the surgery of KW were also significantly reduced (P 0.05). Conclusion In the treatment of extra-articular fractures of the distal tibia with nails, KW as blocking screws technique is safe and reliable.

Background External fixators (EFs) and intramedullary nailing (IMN) are two effective methods for open tibial fractures. However, both methods have advantages and disadvantages, and the optimal surgical approach remains controversial. Thus, we performed a meta-analysis of randomized controlled trials (RCTs) to compare EF with IMN to evaluate their efficacy and safety. Methods A systematic study of the literature was conducted in relevant studies published in PubMed, Embase, the Cochrane Library, Web of Science, CNKI, CBM, Wanfang and Weipu from database inception to April 2022. All eligible literature was critically appraised for methodological quality via the Cochrane's collaboration tool. The primary outcome measurements included postoperative superficial infection, postoperative deep infection, union time, delayed union, malunion, nonunion, and hardware failure. Results Nine RCTs involving 733 cases were included in the current meta-analysis. The pooled results suggested that cases in the IMN group had a significantly lower postoperative superficial infection rate [risk ratio (RR) = 2.84; 95% confidence interval (CI) = 1.83 to 4.39; P P P = 0.02). There were no significant differences in the postoperative deep infection rate, union time, delayed union rate or nonunion rate between the two groups (p > 0.05). Conclusions Compared to EF, IMN had a significantly lower risk of postoperative superficial infection and malunion in patients with open tibial fractures. Meanwhile, IMN did not prolong the union time and increased the risk of the deep infection rate, delayed union rate and nonunion rate but had a higher hardware failure rate. The reanalysis of union time showed that it was significantly shorter in the IMN group than in the EF group after excluding the study with significant heterogeneity during sensitivity analysis. Therefore, IMN is recommended as a preferred method of fracture fixation for patients with open tibial fractures, but more attention should be given to the problem of hardware failure.

Unmanned aerial vehicle (UAV)-enabled wireless power transfer (WPT) has recently emerged as a promising technique to provide sustainable energy supply for widely distributed low-power ground devices (GDs) in large-scale wireless networks. Compared with the energy transmitters (ETs) in conventional WPT systems which are deployed at fixed locations, UAV-mounted aerial ETs can fly flexibly in the three-dimensional (3D) space to charge nearby GDs more efficiently. This paper provides a tutorial overview on UAV-enabled WPT and its appealing applications, in particular focusing on how to exploit UAVs’ controllable mobility via their 3D trajectory design to maximize the amounts of energy transferred to all GDs in a wireless network with fairness. First, we consider the single-UAV-enabled WPT scenario with one UAV wirelessly charging multiple GDs at known locations. To solve the energy maximization problem in this case, we present a general trajectory design framework consisting of three innovative approaches to optimize the UAV trajectory, which are multi-location hovering, successive-hover-and-fly, and time-quantization-based optimization, respectively. Next, we consider the multi-UAV-enabled WPT scenario where multiple UAVs cooperatively charge many GDs in a large area. Building upon the single-UAV trajectory design, we propose two efficient schemes to jointly optimize multiple UAVs’ trajectories, based on the principles of UAV swarming and GD clustering, respectively. Furthermore, we consider two important extensions of UAV-enabled WPT, namely UAV-enabled wireless powered communication networks (WPCN) and UAV-enabled wireless powered mobile edge computing (MEC), by integrating the emerging WPCN and MEC techniques, respectively. For both cases, we investigate the UAV trajectory design jointly with communication/computation resource allocations to optimize the system performance, subject to the energy availability constraints at GDs. Finally, open problems in UAV-enabled WPT and promising directions for its future research are discussed.

Most of the previous studies have investigated the detonation and combustion characteristics of hydrogen and air mixtures, but the change process of hydrogen-air recombination reaction at ambient temperature is unclear. In this study, the variation of temperature and hydrogen conversion during the H2-air mixture reaction catalyzed by Pt/C catalyst was examined. Experiments were carried out in a small-scale cylindrical vessel to investigate the effects of hydrogen volume fraction, catalyst mass, and inlet gas flow rate on the reaction process. The results revealed that the reaction temperature climbed as the hydrogen volume fraction increased, with a peak value achieved when the hydrogen volume fraction reached 35 vol%, and subsequently reduced as the hydrogen volume fraction increased further. The increase of the inlet gas flow rate also promoted the growth of reaction temperature. However, there was no significant linear relationship between the rise of catalyst mass and the change of reaction temperature.

Accidents involving hydrogen explosions occur frequently, yet systematic methods of explosion suppression have not been investigated and applied. Therefore, this paper studied the deflagration characteristics in hydrogen with the addition of propane in the tube filled with mesh aluminium alloys (MAAs). The effects of different propane contents and different filling densities (the mass of MAAs per unit volume in a vessel) on the explosion suppression of the premixed gas are examined. The results show that propane and MAAs can effectively suppress the hydrogen-air explosion. However, MAAs have multiple suppression/promotion effects on the propane-hydrogen explosion. Based on the mathematical model, the dominant effect of MAAs changes abruptly toward the promoting effect when the hydrogen content exceeds 72.26% of the premixed gas stoichiometric concentration. It is also found that an increase in filling density would have a beneficial effect on explosion suppression. The study results provide references for preventing hydrogen and hydrogenated hydrocarbon fuels explosions and optimizing the performance of MAAs.

OBJECTIVE: To analyze the expression of type Ⅱ inflammatory-related cytokines in nasal secretions of patients with eosinophilic chronic rhinosinusitis with nasal polyps(ECRSwNP), and to preliminarily explore the role of type Ⅱ inflammatory cytokines in nasal secretions in predicting ECRSwNP. METHODS: A prospective analysis was made of 91 patients with CRSwNP who underwent endoscopic sinus surgery in Peking University Third Hospital from November 2020 to June 2021. All the selected patients had their SNOT-22 score, Lund-Mackay score and blood eosinophilia collected before surgery. Percentage and absolute value; the nasal secretions of patients were collected before operation, and enzyme-linked immunosorbent assay was used to detect the typeⅡinflammatory cytokines(IL-4, IL-5, IL-13, IL-25, IL-33, Eotaxin-3, periostin), intraoperative nasal polyp tissue was collected for eosinophil count. According to the proportion of eosinophils in the tissue≥10%, they were divided into ECRSwNP group and nECRSwNP group. The clinical baseline data and type Ⅱ inflammatory cytokines were compared between the two groups, and the related factors of ECRSwNP were evaluated by univariate logistic regression analysis. The receiver operating characteristic(ROC) curve was used to evaluate the predictive potential of each clinical index. RESULTS: The SNOT-22 score, Lund-Mackay score, blood eosinophil percentage and absolute value in the ECRSwNP group were higher than those in the nECRSwNP group(P < 0.05). In the nECRSwNP group(P < 0.01). Logistic regression analysis found that IL-5, Eotaxin-3 and blood eosinophil percentage were risk factors for ECRSwNP(P < 0.05). ROC analysis found that IL-5, Eotaxin-3 and blood eosinophil percentage had predictive diagnostic value(P < 0.01), among which blood eosinophil percentage had the greatest predictive value(AUC=0.756). The prediction model composed of Eotaxin-3, SNOT-22 score, sinus CT Lund-Mackay score, blood eosinophil percentage and blood eosinophil absolute value had better prediction effect on ECRSwNP(AUC=0.873). CONCLUSION: Type Ⅱ inflammatory cytokines IL-5 and Eotaxin-3 in nasal secretions may be involved as biomarkers for early diagnosis of ECRSwNP.

This study seeks to discover the change of cloud's expansion rate with self-designed shock wave dispersion system. Transmission, diffraction and reflection could be observed intuitively when shock waves passed through solid particle layers. Results show that the longitudinal motion of particle group greatly influenced cloud's volume growth, thus, the maximum rate of longitudinal expansion of clouds was almost twice that of lateral expansion. The cloud growth rate and volume acceleration increased with smaller particle size, thicker particle layer and stronger shock wave intensity. Also, the expansion rate initially had a drastic decrease, small particles made clouds volume acceleration unstable and experienced a subsequent swift rise. Shock wave intensity influenced diffraction and reflection formation waves as well as the cloud's shape and expansion rate. This study therefore proposed a controlling model for cloud's expansion rate, which could illustrate differences between acceleration stage of dynamic action and deceleration stage of resistance action.

The etiologies of chronic rhinosinusitis with nasal polyps (CRSwNP)-associated olfactory dysfunction have several potentially overlapping hypotheses. Understanding the association of tissue eosinophils and mucous inflammatory cytokines with olfactory function and identifying predictors of olfactory outcomes in patients with nasal polyposis after surgery is fundamental for future clinical care and research.Eighty-five patients who underwent endoscopic surgery for nasal polyposis were enrolled in this study. Olfactory measurements were performed before surgery and 3-6 months after surgery using a TT olfactometer. Baseline characteristics of CRSwNP patients were collected, and Spearman's rho correlation was performed to assess the association of olfactory function with tissue eosinophils and mucous inflammatory cytokines. A multivariate logistic regression model was used to assess the independent predictors of olfactory outcomes after surgery.Here, 85 CRSwNP patients, including 25 patients without olfactory disorder and 60 patients with hypo-anosmia, were evaluated. Of the 60 patients with preoperative hypo-anosmia, 22 did not have improved olfactory function, and 38 demonstrated normal olfactory function after surgery based on the TT olfactometer results. The levels of tissue eosinophil, interleukin-5 (IL-5), IL-13, eotaxin-3, and periostin in the preoperative hypo-anosmia group were higher than those in the preoperative normosmia group. Tissue eosinophil count, IL-5, and periostin levels in patients without olfactory improvement were higher than those in patients with olfactory improvement. The tissue eosinophil count, blood eosinophil count, and nasal mucus levels of IL-5, eotaxin-3, and periostin were significantly correlated with olfactory function in all patients with CRSwNP. The IL-5 level remained a strong predictor of poor olfactory outcomes after surgery.Both tissue eosinophils and mucous inflammatory cytokines, including IL-5, IL-13, eotaxin-3, and periostin, may contribute to the pathogenesis of CRSwNP-associated olfactory dysfunction. Higher IL-5 levels are associated with a lower chance of olfactory function recovery after each surgical revision.

To explore an effective way to prevent and control the hydrogen explosion accidents, closed explosion experiments involving hydrogen-air mixtures were carried out in a 2 m-long cylindrical tube under the influences of mesh aluminum alloys (MAAs) and spherical nonmetallic materials (SNMs). The results show that with the increase of filling diameter, the overpressure of hydrogen-air mixtures under the influence of MAAs and SNMs decreases gradually in general, and the flame velocity shows a same trend. MAAs and SNMs have a promotion/suppressing double functions on the deflagration of hydrogen-air mixtures and SNMs show a better suppressing effect than MAAs. It is also found that the deflagration to detonation transition (DDT) is more difficult achieved for larger filling density and larger filling diameter of MAAs and SNMs. In addition, several different DDT mechanisms are discussed in detail, including DDT caused by Mach-stem reflection and by direct initiation due to shock focusing. Based on a mathematical model, a prediction value of 184.30 kg/m3 (filling density of MAAs) may be satisfy the explosion-suppression evaluation criteria according to the Chinese standard AQ3001-2005. These results provide references for preventing explosions of hydrogen-air mixtures and for optimizing the performance of MAAs and SNMs.

An experimental study was carried out to investigate the flame propagation and thermal hazard of the premixed N2O/fuel mixtures, including NH3, C3H8 and C2H4. The study provided the high speed video images and data about the flame locations, propagation patterns, overpressures and the quenching diameters during the course of combustion in different channels to elucidate the dynamics of various combustion processes. The onset decomposition temperature was determined using high-performance adiabatic calorimetry. It was shown that the order of the flame acceleration rate and thermal hazard was N2O/C2H4>N2O/C3H8>N2O/NH3.

The density functional theory (DFT) was applied to investigate the structure, optical properties, and non-bonded interactions of the cyclo-pentazolate salt [Mg(H2O)6(N5)2]·4H2O in the pressure range of 0–100 GPa. The results show that there is a structural transition at the pressure of 64 GPa, which has not been found in the experiments. As the pressure increases, the band gap gradually decreases with a sudden increase at the structural transition point. The analysis of DOS presents that the electronic localization in the crystal gradually weakens under the pressure. The structural transition point also exists in the hydrogen bonds and the Hirshfeld surfaces under compression. The absorption spectra of the cyclo-pentazolate salt at high pressures show some strong bands in the fundamental absorption region. The increasing pressure helps to improve the photoelectric performances of the crystal. Our studies are expected to provide a new understanding of the structural transition of the novel energetic materials under high pressures.

Experiments were conducted in a 2 m large duct with an internal diameter of 70 mm, to investigate the effects of the vent area and ignition position on pressure oscillations with different methane concentrations. The results showed that violent pressure oscillations occurred when methane concentrations were between 9.5 and 12 vol. % in the closed duct. End ignition was shown to dampen the pressure oscillations to a significant extent. In addition, vented explosions could also reduce the pressure oscillations where the amplitude of the pressure oscillations decreases with increasing vented area. For a vent area of 38.5 cm2, no pressure oscillations occurred in all tests. Central ignition produced the larger pressure peak only when the vent area was small.

Zirconium powder, a main potential dangerous source in nuclear industry, has been focused on its explosion characteristics in this paper. Experiments were performed in a 20 L cylindrical explosion vessel with the influences of initial ignition energy, ignition delay time and zirconium concentration. Results showed that the maximum explosion pressure of zirconium-air mixture rose with the increase of the initial ignition energy, and a peak value was obtained with the variation of the ignition delay time. Lower explosion limit with the initial ignition energy of 10 kJ is 10 g/m³. Furthermore, explosion severity parameters, including maximum explosion pressure, maximum rate of pressure rise and maximum explosion index of zirconium-air mixture, were also obtained with the coupling variation between initial ignition energy and dust concentration. Research results and data obtained are a supplement to the utilization and safety operation of zirconium powders.

Detonation characteristics of hydrocarbon fuels are important indexes for their safety evaluation and protection. To investigate the detonation characteristic of alkane homologs series and the influence of different molecular energies, alkane homologs series’ critical energy to direct detonation (hereinafter related to as critical energy) and detonation cellular width were measured by a self-designed shock tube. Then, the molecular total energy (E) and bond dissociation energy (BDE) of fuel molecules were calculated by the quantum chemistry method. After the comparison between detonation characteristics and molecular energies, it is found that for alkane homologs series, molecular total energy was found to have a good exponent relation between critical energy and detonation cellular width, which indicated that the detonation sensitivity of alkane homologs series can be predicted based on total energy of fuel molecules with preferable accuracy. Extra experiment and calculation was also carried out on gaseous hydrocarbon fuels (ethane, ethylene and acetylene) with same carbon atom number. Results indicated that the bond dissociation energy may have the impact on the detonation cellular width for these three gaseous fuels. The bigger bond dissociation energy leads to smaller cellular width.

Vented explosion experiments involving hydrogen-air mixtures are performed in a 2 m-long cylindrical tube under the influences of the hydrogen concentration and vent burst pressure. Photos of the external flame shot by a high-speed camera show that the jet flame was expelled outside the vessel, and the relation between the flame propagation and external overpressure is summarized. The internal peak overpressure increases and then decreases with increasing hydrogen concentration. In contrast, the external peak overpressure exhibits the opposite correlation in comparison with the internal peak overpressure. The variations in the pressure peaks of the internal pressure curves are also discussed. When the hydrogen concentration is lower than 40 vol %, the second pressure peak plays a more dominant role than the other pressure peaks. However, when the hydrogen concentration is higher than 40 vol %, the third pressure peak becomes more dominant.

Background Despite current advances in gastric cancer treatment, disease metastasis and chemo-resistance remain as major hurdles against better overall prognosis. Previous studies indicated that IGHG1 as well as -Catenin serve as important regulators of tumor cellular malignancy. Therefore, understanding detailed molecular mechanism and identifying druggable target will be of great potentials in future therapeutic development. Methods Surgical tissues and gastric cancer cell lines were retrieved to evaluate IGHG1 expression for patients with or without lymph node/distal organ metastasis. Functional assays including CCK8 assay, Edu assay, sphere formation assay and transwell assay, wound healing assay, etc. were subsequently performed to evaluate the impact of IGHG1/-catenin axis on tumor cell proliferation, migration and chemo-resistance. Results Gastric cancer tissues and tumor cell lines demonstrated significantly higher level of IGHG1. Functional study further demonstrated that IGHG1 promoted proliferative and migration as well as chemo-resistance of gastric cancer tumor cells. Further experiments indicated that IGHG1 activated AKT/GSK-3/-Catenin axis, which played crucial role in regulation of proliferative and chemo-resistance of gastric cancer cells. Conclusion This study provided novel evidences that IGHG1 acted as oncogene by promotion of gastric cancer cellular proliferation, migration and chemo-resistance. Our research further suggested that IGHG1/AKT/GSK-3β/β-Catenin axis acted as novel pathway which regulated gastric cancer cellular malignant behavior. Our research might inspire future therapy development to promote overall prognosis of gastric cancer patients.

Developing of inexpensive, high-efficient, and earth-abundant bifunctional catalysts for water splitting is of great significance for green and sustainable energy development. Herein, a bifunctional hybrid electrocatalyst of Ni3ZnC0.7 nanodots in-situ grown on nitrogen-doped carbon nanotube (Ni3ZnC0.7/NCNT) arrays is synthesized by a one-step template strategy with 1, 3, 5-triamino-2, 4, 6-trinitrobenzene serving as carbon/nitrogen sources, ZnO nanorods as template and zinc source, and nickel foam as substrate and nickel source. Benefiting from the introduction of Ni3ZnC0.7 nanodots and nitrogen doping to the carbon nanotubes, the Ni3ZnC0.7/NCNT-700 arrays exhibit superior hydrogen evolution reaction and oxygen evolution reaction catalytic activity in terms of low overpotential (203 mV and 380 mV vs RHE at 10 mA cm−2 for hydrogen evolution reaction and oxygen evolution reaction, respectively). When the Ni3ZnC0.7/NCNT-700 is served as both anode and cathode catalysts for overall water splitting, a potential of 1.66 V is needed to deliver a current density of 10 mA cm−2, and it also displays negligible degradation after 24 h of operation in alkaline solution. The present work not only provides an efficient bifunctional electrocatalyst for overall water splitting, but also offers a new strategy to design and synthetize the bimetallic carbide.

To investigate the solubility of carbon dioxide (CO2) in geological fluids at different temperatures and pressures, we developed a method for measuring solubility using an optically transparent fus...

Experimental study of explosion prevention has been performed in the oil tank filled with suppression material. The kerosene in the pool is used as the fuel to ignite the gasoline and diesel oil ta...

Landslides constitute a severe environmental problem in Jiangxi, China. This research was aimed at conducting landslide hazard assessment to provide technical support for disaster reduction and prevention action in the province. Fourteen geo-environmental factors, e.g., slope, elevation, road, river, fault, lithology, rainfall, and land cover types, were selected for this study. A test was made in two cases: (1) only based on the main linear features, e.g., main rivers and roads, and (2) with detailed complete linear features including all levels of roads and rivers. After buffering of the linear features, an information value (IV) analysis was applied to quantify the distribution of the observed landslides for each subset of the 14 factors. The results were inputted into the binary logistic regression model (LRM) for landslide risk modeling, taking the known landslide points as a training set (70% of the total 9,525 points). The calculated probability of a landslide was further classified into five grades with an interval of 0.2 for hazard mapping: very high (3.70%), high (4.05%), moderate (18.72%), low (27.17%), and stable zones (46.36%). The accuracy was evaluated by AUC [the area under the receiver operating characteristic (ROC) curve] vs. the validation set (30%, the remaining landslides). The final results show that with increasing the completeness of the linear features, the modeling reliability also significantly increased. We hence concluded that the tested methodology is capable of achieving the landslide hazard prediction at regional scale, and the results may provide technical support for geohazard reduction and prevention in the studied province.

This letter studies a cellular-connected unmanned aerial vehicle (UAV) scenario, in which a UAV user communicates with ground base stations (GBSs) in cellular uplink by sharing the spectrum with ground users (GUs). To deal with the severe air-to-ground (A2G) co-channel interference, we consider an adaptive interference cancellation (IC) approach, in which each GBS can decode the GU's messages by adaptively switching between the modes of IC (i.e., precanceling the UAV's resultant interference) and treating interference as noise (TIN). By designing the GBSs' decoding modes, jointly with the wireless resource allocation and the UAV's trajectory control, we maximize the UAV's data-rate throughput over a finite mission period, while ensuring the minimum data-rate requirements at individual GUs. We propose an efficient algorithm to solve the throughput maximization problem by using the techniques of alternating optimization and successive convex approximation (SCA). Numerical results show that our proposed design significantly improves the UAV's throughput as compared to the benchmark schemes without the adaptive IC and/or trajectory optimization., Comment: Technical Report

Asymmetry in a retrusive cleft-side ala situated posterior, lateral, and/or inferior to the non-cleft ala is aggravated by ipsilateral defect of the pyriform aperture. This study assessed diced costal cartilage graft combined with muscle repositioning in enhancing structural base and alar symmetry in secondary cleft rhinoplasty.From 2016 to 2019, 20 consecutive patients who underwent pyriform aperture paranasal augmentation combined with muscle repair secondary unilateral cleft rhinoplasty were reviewed retrospectively. Clinical three-dimensional (3D) photos were analyzed pre- and postoperatively, and the augmentation method and muscle repositioning were described detailedly.Twenty cases aged 22.2 ± 3.9 years were submitted to secondary cleft rhinoplasty with diced costal cartilage graft to the pyriform rim. They were followed up for 6.2-26.2 months, with postsurgical time averaging 10.3 ± 3.4 months. After total lip takedown by anatomic muscle re-approximation, the cleft to non-cleft side showed enhanced alar symmetry (p 0.001) and heightened vertical lip length (p 0.001). Additionally, the alar base inclination was improved toward the horizontal plane (p 0.001).The cleft-side ala was anatomically ameliorated after muscle repositioning combined with diced costal cartilage graft to the pyriform rim, improving alar symmetry. Complications were minimal, indicating the safety of this method.

Objective To explore the association of circadian rhythm disruption with polycystic ovary syndrome (PCOS) and the potential underlying mechanism in ovarian granulosa cells (GCs). Design Multicenter questionnaire-based survey, in vivo and ex vivo studies. Setting Twelve hospitals in China, animal research center, and research laboratory of a women’s hospital. Patients/Animals A total of 436 PCOS case subjects and 715 control subjects were recruited for the survey. In vivo and ex vivo studies were conducted in PCOS-model rats and on ovarian GCs collected from women with PCOS and control subjects. Intervention(s) The PCOS rat model was established with the use of testosterone propionate. Main Outcome Measure(s) Assay for transposase-accessible chromatin with high-throughput sequencing (ATAC-seq), RNA sequencing, rhythmicity analysis, functional enrichment analysis. Result(s) There was a significant correlation between night shift work and PCOS. PCOS-model rats presented distinct differences in the circadian variation of corticotropin-releasing hormone, adrenocorticotropic hormone, prolactin, and a 4-h phase delay in thyrotropic hormone levels. The motif enrichment analysis of ATAC-seq revealed the absence of clock-related transcription factors in specific peaks of PCOS group, and RNA sequencing ex vivo at various time points over 24 hours demonstrated the differential rhythmic expression patterns of women with PCOS. Kyoto Encyclopedia of Genes and Genomes analysis further highlighted metabolic dysfunction, including both carbohydrate and amino acid metabolism and the tricarboxylic acid cycle. Conclusion(s) There is a significant association of night shift work with PCOS, and genome-wide chronodisruption exists in ovarian GCs.

Rare earth elements (REE) mines have an extremely high strategic value, especially, in national aerospace industry and military fields. The long-term open mining and extraction processing of REE in the weathered crust since 1970s have led to serious land degradation, e.g., vegetation degradation, soil loss, reduction of soil fertility, and especially, environmental pollution to subsoil and groundwater. Taking southern Jiangxi, where ion-type of REE mines are mainly located, as an instance, the total mining area is measured about 79 km2 from 1291 mines, of which 56 km2 have been or are being managed with restoration measures identified by comparison between multitemporal very high resolution images available on Google Earth. Visual interpretation revealed that large-scale mining activities occurred after 2000 and restoration management was not intervened until 2010, in particular, 2013. As implemented by different enterprises or companies, post-mining restoration has a strong spatial variability in both management approaches and effectiveness from mine to mine. Up to today, no systematic monitoring and assessment have been conducted for this restoration intervention. It is, therefore, the objective of our study to evaluate the effectiveness of such restoration efforts using multitemporal October Landsat data with scene path/row number of 121/42-121/43 from 2000 to 2017. Eight managed and seven unmanaged typical mines were selected for a comparative analysis and restoration assessment.After atmospheric correction using COST model, NDVI and GDVI (Generalized Difference Vegetation Index) that is more suitable for low vegetation, as proxy of vegetation vigor and biomass production, were derived from all satellites images. The mean NDVI and GDVI values of each selected mine were calculated. The results show that NDVI of the managed REE mines has been increasing from 0.32 to 0.67 and GDVI from 0.55 to 0.90 year by year since 2010, indicating a vegetation recovery, especially, for those with effective management. In contrast, in the unmanaged mines, NDVI values remain low ranging from 0.20 to 0.40, and GDVI from 0.22 to 0.60, implying that the damaged vegetation cover caused by open mining and pollution has low capacity to recover without human intervention, where continue serious water loss and soil erosion. We also noted in some managed areas that planted grasses have survived but trees died or are dying probably because of the residual pollution in subsoil. This means a holistic management should be implemented in both surface, subsoil and groundwater, and monitoring be conducted by remote sensing in combination with soil sampling. This will be our next task of research.

This paper studies an unmanned aerial vehicle (UAV)-enabled wireless sensor network, in which one UAV flies in the sky to collect the data transmitted from a set of sensors via distributed beamforming. We consider the delay-sensitive application scenario, in which the sensors transmit the common/shared messages by using fixed data rates and adaptive transmit powers. Under this setup, we jointly optimize the UAV's trajectory design and the sensors' transmit power allocation, in order to minimize the transmission outage probability, subject to the UAV's flight speed constraints and the sensors' individual average power constraints. However, the formulated outage probability minimization problem is non-convex and thus difficult to be optimally solved in general. To tackle this issue, we first consider the special problem in the ideal case with the UAV's flight speed constraints ignored, for which the well-structured optimal solution is obtained to reveal the fundamental performance upper bound. Next, for the general problem with the UAV's flight speed constraints considered, we propose an efficient algorithm to solve it sub-optimally by using the techniques of convex optimization and approximation. Finally, numerical results show that our proposed design achieves significantly reduced outage probability than other benchmark schemes., Comment: 6 pages, 4 figures, ICC 2020 workshop

This paper studies an unmanned aerial vehicle (UAV)-enabled wireless sensor network, in which one UAV flies in the sky to collect the data transmitted from a set of ground nodes (GNs) via distributed beamforming. We consider two scenarios with delay-tolerant and delay-sensitive applications, in which the GNs send the common/shared messages to the UAV via adaptive- and fixed-rate transmissions, respectively. For the two scenarios, we aim to maximize the average data-rate throughput and minimize the transmission outage probability, respectively, by jointly optimizing the UAV's trajectory design and the GNs' transmit power allocation over time, subject to the UAV's flight speed constraints and the GNs' individual average power constraints. However, the two formulated problems are both non-convex and thus generally difficult to be optimally solved. To tackle this issue, we first consider the relaxed problems in the ideal case with the UAV's flight speed constraints ignored, for which the well-structured optimal solutions are obtained to reveal the fundamental performance upper bounds. It is shown that for the two approximate problems, the optimal trajectory solutions have the same multi-location-hovering structure, but with different optimal power allocation strategies. Next, for the general problems with the UAV's flight speed constraints considered, we propose efficient algorithms to obtain high-quality solutions by using the techniques from convex optimization and approximation. Finally, numerical results show that our proposed designs significantly outperform other benchmark schemes, in terms of the achieved data-rate throughput and outage probability under the two scenarios. It is also observed that when the mission period becomes sufficiently long, our proposed designs approach the performance upper bounds when the UAV's flight speed constraints are ignored., Comment: Double-column, 15 pages, 8 figures, 4 tables. Accepted for publication in the IEEE Transactions on Wireless Communications. It overlaps with the former version (arXiv:2004.11332)

The flame propagation behavior of premixed N2O–NH3/N2O–NH3–C3H8 was experimentally investigated in elongated vented cylindrical vessels with central ignition. The effect of vessel diameter and prop...

Defect engineering is a vital technique to modulate the properties of carbon nanomaterials. The unique advantage of intentionally introducing intrinsic defects and heteroatom dopants in sp2 C–C bond framework is to increase the active sites, optimize the adsorption/desorption behavior of the reaction intermediates, and alter the surface charge transfer properties of various electrochemical systems. Herein, a defects and bonding disorder regulation strategy is reported to enhance both catalytic activity and combustion reactivity of sp2 carbon toward the thermal decomposition and combustion of ammonium perchlorate (AP), which is the key reaction of modern solid propellants in aerospace field. A layered defect-rich carbon (LDC) has been prepared by inlayer carbonization of graphite-like 1,3,5-Triamino-2,4,6-trinitrobenzene (TATB) crystals. The intentionally designed LDC with rich intrinsic defects and N dopants provides abundant active sites for adsorption of AP decomposition intermediates, which facilitates efficient charge transfer in rate controlling steps. Moreover, the LDC with high bond disorder can react with AP as fuel with high reaction kinetics. As compared to other carbon materials with different bonding disorder and defects, this highly reactive catalyst greatly enhances the combustion performance of AP/LDC composites in terms of more complete chemical energy release (increased combustion pressure) and enhanced reaction kinetics (increased burning rate). The defect engineering provides an effective way to activate the inert sp2 carbon materials to efficient combustion catalysts and highly reactive fuels for AP based solid propellants.

Controllable construction of self-supporting electrodes with efficient charge migration on the whole electrode and abundant electrocatalytic active sites is still challenging in oxygen evolution reaction (OER). Here, an intentionally designed self-supporting electrode consisting of NiCoP nanowire arrays embedded in 3D integrated N-doped carbon network (NiCoP@NC-NCNTs) is fabricated for high-performance electrocatalytic OER. The NiCoP@NC-NCNTs has been prepared via in-situ growth of N-doped carbon nanotubes (NCNTs) and N-doped carbon (NC) layer on NiCo arrays and subsequent phosphating reaction. Due to the intertwined network structure of NCNTs and the conformal coating of NC layer on the surface of NiCoP arrays, the NiCoP@NC-NCNTs catalyst not only realizes effective charge migration on the whole electrode, but also offers abundant catalytic active sites. Compared to NiCoP nanowire arrays without embedding in 3D carbon network, the NiCoP@NC-NCNTs exhibits a remarkable performance for electrocatalytic OER, in terms of an ultralow overpotential of 227 mV at 10 mA cm−2, and 317 mV even at 100 mA cm−2. Meanwhile, a negligible current degradation can be found in the chronoamperometric (i-t) curve after the long-term stability test. This work proves that it is a promising strategy to develop electrocatalysts by embedding the bimetallic phosphides in 3D carbon networks.