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Objective: The general practice (GP) system is associated with patient-centeredness, high-quality general practitioners, and comprehensive digital information technology. Therefore, it has been promoted greatly over the recent years in China. However, there is a relatively insufficient number of patients in the general outpatient department of comprehensive tertiary hospitals in China. Therefore, the aim of the present paper is to analyze the specific influencing factors and triage accuracy in the general clinic of Syndrome Hospital. Methods: The work involves the use of a questionnaire designed to probe the influencing factors, through the survey of 389 patients. According to different departments, the patients were enrolled into a GP group (n = 126) and a specialized practice (SP) group (n = 263). The basic information and survey results of the patients were obtained, and the reasons influencing the choice of the department were analyzed. In addition, the triage accuracy by general practitioners was assessed. Results: The age, position, current residence, education level, payment method, annual income, awareness of GP diagnosis and treatment policies, self-conscious severity of disease, and registration method of patients in the GP group were obviously different from those in the SP group (P < .05). Self-payment, annual income ≤ 5 w, high and medium level of awareness of GP diagnosis and treatment policies, and on-site registration were the influencing factors for patients' choice of GP. The triage accuracy of general practitioners (89.29%) was higher than that of guidance doctors, registered triage, and online expert consultation (76.05%) (P < .05). Conclusion: The GP diagnosis and treatment policies exhibited a high value of clinical promotion. Self-payment, low annual income, awareness of GP policies, and registration mode affected the patients' choice of GP, and the triage accuracy by general practitioners was higher compared to SP.
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Medicina General , Médicos Generales , Humanos , Triaje/métodos , Pacientes Ambulatorios , HospitalesRESUMEN
Inevitable interactions with the reservoir largely degrade the performance of entangling gates, which hinders practical quantum computation from coming into existence. Here, we experimentally demonstrate a 99.920(7)%-fidelity controlled-not gate by suppressing the complicated noise in a solid-state spin system at room temperature. We found that the fidelity limited at 99% in previous works results from considering only static classical noise, and, thus, in this work, a complete noise model is constructed by also considering the time dependence and the quantum nature of the spin bath. All noises in the model are dynamically corrected by an exquisitely designed shaped pulse, giving the resulting error below 10^{-4}. The residual gate error is mainly originated from the longitudinal relaxation and the waveform distortion that can both be further reduced technically. Our noise-resistant method is universal and will benefit other solid-state spin systems.
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To date, only a few noble metal oxides exhibit the required efficiency and stability as oxygen evolution reaction (OER) catalysts under the acidic, high-voltage conditions that exist during proton exchange membrane water electrolysis (PEMWE). The high cost and scarcity of these catalysts hinder the large-scale application of PEMWE. Here, we report a novel OER electrocatalyst for OER comprised of uniformly dispersed Ru clusters confined on boron carbon nitride (BCN) support. Compared to RuO2 , our BCN-supported catalyst shows enhanced charge transfer. It displays a low overpotential of 164â mV at a current density of 10â mA cm-2 , suggesting its excellent OER catalytic activity. This catalyst was able to operate continuously for over 12â h under acidic conditions, whereas RuO2 without any support fails in 1â h. Density functional theory (DFT) calculations confirm that the interaction between the N on BCN support and Ru clusters changes the adsorption capacity and reduces the OER energy barrier, which increases the electrocatalytic activity of Ru.
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Stray current affects the safe operation of subway equipment. The stray current leakage point can be located by measuring the current of subway running track. A magnetostrictive current sensor with high sensitivity and a large linear range is proposed to monitor track current. The design of the sensor is qualitatively guided by a set of finite element method (FEM) simulations to improve the sensitivity of the sensor. However, when the sensitivity of the sensor increases, the linear range decreases. To solve this problem, a novel current sensor, to the best of our knowledge, which is composed of magnetostrictive composites, steel bars, and adjustable coils, is presented. The linear range of the sensor is expanded by adjusting the different DC bias magnetic fields generated by the adjustable coils. The results show that when the measured current is 0-500 A and 500-1000 A, the Terfenol-D (TD) mass is only 0.14 g, and the sensitivity of the sensor is 0.391 µÉ/A and 0.418 µÉ/A, respectively. The current measurement with low cost, high sensitivity, and larger linear working range is realized, which is suitable for monitoring stray current leakage points.
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With the rapid development of vehicular networks, vehicle-to-everything (V2X) communications have huge number of tasks to be calculated, which brings challenges to the scarce network resources. Cloud servers can alleviate the terrible situation regarding the lack of computing abilities of vehicular user equipment (VUE), but the limited resources, the dynamic environment of vehicles, and the long distances between the cloud servers and VUE induce some potential issues, such as extra communication delay and energy consumption. Fortunately, mobile edge computing (MEC), a promising computing paradigm, can ameliorate the above problems by enhancing the computing abilities of VUE through allocating the computational resources to VUE. In this paper, we propose a joint optimization algorithm based on a deep reinforcement learning algorithm named the double deep Q network (double DQN) to minimize the cost constituted of energy consumption, the latency of computation, and communication with the proper policy. The proposed algorithm is more suitable for dynamic scenarios and requires low-latency vehicular scenarios in the real world. Compared with other reinforcement learning algorithms, the algorithm we proposed algorithm improve the performance in terms of convergence, defined cost, and speed by around 30%, 15%, and 17%.
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The alkaline stability of N-heterocyclic ammonium (NHA) groups is a critical topic in anion-exchange membranes (AEMs) and AEM fuel cells (AEMFCs). Here, we report a systematic study on the alkaline stability of 24 representative NHA groups at different hydration numbers (λ) at 80 °C. The results elucidate that γ-substituted NHAs containing electron-donating groups display superior alkaline stability, while electron-withdrawing substituents are detrimental to durable NHAs. Density-functional-theory calculations and experimental results suggest that nucleophilic substitution is the dominant degradation pathway in NHAs, while Hofmann elimination is the primary degradation pathway for NHA-based AEMs. Different degradation pathways determine the alkaline stability of NHAs or NHA-based AEMs. AEMFC durability (from 1â A cm-2 to 3â A cm-2 ) suggests that NHA-based AEMs are mainly subjected to Hofmann elimination under 1â A cm-2 current density for 1000â h, providing insights into the relationship between current density, λ value, and durability of NHA-based AEMs.
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For the treatment of low C/N wastewaters, methanol or acetate is usually dosed as electron donor for denitrification but such organics makes the process costly. To decrease the cost, iron which is the fourth most abundant element in lithosphere is suggested as the substitution of methanol and acetate. The peak volumetric removal rate (VRR) of nitrate nitrogen in the ferrous iron-dependent nitrate removal (FeNiR) reactor was 0.70 ± 0.04 kg-N/(m3·d), and the corresponding removal efficiency was 98%. Iron showed toxicity to cells by decreasing the live cell amount (dropped 56%) and the live cell activity (dropped 70%). The toxicity of iron was mainly expressed by the formation of iron encrustation. From microbial community data analysis, heterotrophs (Paracocccus, Thauera and Azoarcus) faded away while the facultative chemolithotrophs (Hyphomicrobium and Anaerolineaceae_uncultured) dominated in the reactor after replacing acetate with ferrous iron in the influent. Through scanning electron microscope (SEM) and transmission electron microscope (TEM), two iron oxidation sites in FeNiR cells were observed and accordingly two FeNiR mechanisms were proposed: 1) extracellular FeNiR in which ferrous iron was bio-oxidized extracellularly; and 2) intracellular FeNiR in which ferrous iron was chemically oxidized in periplasm. Bio-oxidation (extracellular FeNiR) and chemical oxidation (intracellular FeNiR) of ferrous iron coexisted in FeNiR reactor, but the former one predominated. Comparing with the control group without electron donor in the influent, FeNiR reactor showed 2 times higher and stable nitrate removal rate, suggesting iron could be used as electron donor for denitrification. However, further research works are still needed for the practical application of FeNiR in wastewater treatment.
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Desnitrificación/fisiología , Electrones , Hierro/química , Reactores Biológicos , Compuestos Férricos , Nitratos , Nitrógeno , Oxidación-Reducción , Aguas ResidualesRESUMEN
BACKGROUND: Subclavian vein puncture is commonly used in the intensive care unit (ICU) but is associated with complications. OBJECTIVE: Our aim was to compare the efficacy and safety of static ultrasound-guided subclavian vein puncture with traditional anatomical landmark-guided subclavian vein puncture in critically ill patients in the ICU. METHODS: This pilot randomized controlled trial enrolled patients admitted to the ICU and requiring subclavian vein puncture between November 2017 and September 2018. The patients were randomized to ultrasound-guided puncture or anatomical landmark-guided puncture. The primary outcome measure was the puncture success rate. The secondary outcome measures included the number of punctures, rate of success at the first attempt, puncture time (i.e., procedure duration) and incidence of complications. RESULTS: A total of 194 patients were included in the analyses. Compared with the anatomical landmarks group, the ultrasound group had a higher puncture success rate (91.7% vs. 77.6%; p = 0.007), lower rate of complications (7.3% vs. 20.4%; p = 0.008), and lower incidence of mispuncture of an artery (2.1% vs. 14.3%; p = 0.002). There were no significant differences in the number of punctures and puncture time between the two groups (both, p > 0.05). CONCLUSIONS: Static ultrasound-guided subclavian vein puncture is superior to the traditional landmark-guided approach for critically ill patients in the ICU. It is suggested that static ultrasound-guided puncture techniques should be considered for subclavian vein puncture in the ICU. TRIAL REGISTRATION: ChiCTR1900024051.
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Cateterismo Venoso Central , Vena Subclavia , Cateterismo Venoso Central/efectos adversos , Humanos , Unidades de Cuidados Intensivos , Proyectos Piloto , Punciones , Vena Subclavia/diagnóstico por imagen , Ultrasonografía IntervencionalRESUMEN
Licensed Assisted Access (LAA) is considered one of the latest groundbreaking innovations to provide high performance in future 5G. Coexistence schemes such as Listen Before Talk (LBT) and Carrier Sensing and Adaptive Transmission (CSAT) have been proven to be good methods to share spectrums, and they are WiFi friendly. In this paper, a modified LBT-based CSAT scheme is proposed which can effectively reduce the collision at the moment when Long Term Evolution (LTE) starts to transmit data in CSAT mode. To make full use of the valuable spectrum resources, the throughput of both LAA and WiFi systems should be improved. Thus, a two-layer Coalition-Auction Game-based Transaction (CAGT) mechanism is proposed in this paper to optimize the performance of the two systems. In the first layer, a coalition among Access Points (APs) is built to balance the WiFi stations and maximize the WiFi throughput. The main idea of the devised coalition forming is to merge the light-loaded APs with heavy-loaded APs into a coalition; consequently, the data of the overloaded APs can be offloaded to the light-loaded APs. Next, an auction game between the LAA and WiFi systems is used to gain a win-win strategy, in which, LAA Base Station (BS) is the auctioneer and AP coalitions are bidders. Thus, the throughput of both systems are improved. Simulation results demonstrate that the proposed scheme in this paper can improve the performance of both two systems effectively.
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In this work, a linear birefringence measurement method is proposed for an optical fiber current sensor (OFCS). First, the optical configuration of the measurement system is presented. Then, the elimination method of the effect of the azimuth angles between the sensing fiber and the two polarizers is demonstrated. Moreover, the relationship of the linear birefringence, the Faraday rotation angle and the final output is determined. On these bases, the multi-valued problem on the linear birefringence is simulated and its solution is illustrated when the linear birefringence is unknown. Finally, the experiments are conducted to prove the feasibility of the proposed method. When the numbers of turns of the sensing fiber in the OFCS are about 15, 19, 23, 27, 31, 35, and 39, the measured linear birefringence obtained by the proposed method are about 1.3577, 1.8425, 2.0983, 2.5914, 2.7891, 3.2003 and 3.5198 rad. Two typical methods provide the references for the proposed method. The proposed method is proven to be suitable for the linear birefringence measurement in the full range without the limitation that the linear birefringence must be smaller than π/2.
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In this work, an elimination method of the temperature-induced linear birefringence (TILB) in a stray current sensor is proposed using the cylindrical spiral fiber (CSF), which produces a large amount of circular birefringence to eliminate the TILB based on geometric rotation effect. First, the differential equations that indicate the polarization evolution of the CSF element are derived, and the output error model is built based on the Jones matrix calculus. Then, an accurate search method is proposed to obtain the key parameters of the CSF, including the length of the cylindrical silica rod and the number of the curve spirals. The optimized results are 302 mm and 11, respectively. Moreover, an effective factor is proposed to analyze the elimination of the TILB, which should be greater than 7.42 to achieve the output error requirement that is not greater than 0.5%. Finally, temperature experiments are conducted to verify the feasibility of the elimination method. The results indicate that the output error caused by the TILB can be controlled less than 0.43% based on this elimination method within the range from -20 °C to 40 °C.
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This article describes a novel supramolecular assembly-mediated strategy for the organization of Au nanoparticles (NPs) with different shapes (e.g., spheres, rods, and cubes) into large-area, free-standing 2D and 3D superlattices. This robust approach involves two major steps: (i) the organization of polymer-tethered NPs within the assemblies of supramolecular comblike block copolymers (CBCPs), and (ii) the disassembly of the assembled CBCP structures to produce free-standing NP superlattices. It is demonstrated that the crystal structures and lattice constants of the superlattices can be readily tailored by varying the molecular weight of tethered polymers, the volume fraction of NPs, and the matrix of CBCPs. This template-free approach may open a new avenue for the assembly of NPs into 2D and 3D structures with a wide range of potential applications.
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A polarimetric current sensor based on polarization division multiplexing (PDM) detection is proposed. The novel sensor head with a heat insulation cavity only induces a small level of birefringence. Comparing with polarization diversity (PD) detection, the sensitivity of PDM detection is the double of PD detection. Moreover, PDM detection is more suitable in the presence of the phase modulation error. In addition, the noise and the shifting of the Verdet constant are proved to be the main influence factors of the sensor performance as the source power decline.
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This Letter demonstrates the effect and elimination of alignment error in an optical fiber current sensor. An optical model is built to illustrate the effect of alignment error, which does not induce zero drift and has a large effect on output accuracy. The total alignment error and modulation angle of the polarization controller are defined as k and θ, respectively. Parameter t is equal to 2θ-2k. An elimination method of the error k is proposed, which corrects the angle θ to keep parameter t at 90 deg. This method avoids the measurement of all splice angles separately. Its feasibility is shown by simulation results. In addition, the measurement method and conditions of parameter t are presented. The final t is about 90.24 deg. Furthermore, the effectiveness of the proposed elimination method is proven by a performance test.
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In this paper, a stray current sensor with cylindrical twisted fiber is proposed. The quantitative method of linear birefringence on the sensing fiber is demonstrated. And the temperature-induced linear birefringence is about 4.63 deg per meter at 60 deg centigrade. Then, the demand of circular birefringence is determined based on the polarization division multiplexing model, which is produced by the cylindrical twisted fiber. According to the simulation results, the produced circular birefringence is about 2116.9 deg, which is enough to suppress the linear birefringence. The temperature experiment results indicate the positive effect of the cylindrical twisted fiber, which controls the linear birefringence error within 0.945×10(-5) per degree centigrade. Finally, the performance test results prove the cylindrical twisted fiber improves the accuracy of the stray current sensor. And its repeatability and sensitivity are about 0.367% and 0.0261/A, respectively.
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Improving the utilization of platinum in proton-exchange membrane (PEM) fuel cells is critical to reducing their cost. In the past decade, numerous Pt-based oxygen reduction reaction catalysts with high specific and mass activities have been developed. However, the high activities are mostly achieved in rotating disk electrode (RDE) measurement and have rarely been accomplished at the membrane electrode assembly (MEA) level. The failure of these direct translations from RDE to MEA has been well documented with several key reasons having been previously identified. One of them is the resistance caused by complex mass transport pathways in the MEA. Herein, we improve the proton and oxygen transportations in the MEA by building a thin and uniform distribution of ionomer on the catalyst surface. As a result, a PEM fuel cell design is capable of showing a current density improvement of 38% at the same voltage (0.6 V) under the H2/air operation.
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High-sensitivity detection of the microscopic magnetic field is essential in many fields. Good sensitivity and high spatial resolution are mutually contradictory in measurement, which is quantified by the energy resolution limit. Here we report that a sensitivity of 0.5 nT/[Formula: see text] at the nanoscale is achieved experimentally by using nitrogen-vacancy defects in diamond with depths of tens of nanometers. The achieved sensitivity is substantially enhanced by integrating with multiple quantum techniques, including real-time-feedback initialization, dynamical decoupling with shaped pulses and repetitive readout via quantum logic. Our magnetic sensors will shed new light on searching new physics beyond the standard model, investigating microscopic magnetic phenomena in condensed matters, and detection of life activities at the sub-cellular scale.
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Sludge alkaline fermentation liquid (SAFL) is an alternative to sodium acetate (NaAc) in enhancing wastewater nitrogen removal. Upon SAFL addition, dissolved organic nitrogen (DON) can be externally introduced or biologically synthesized during nitrogen removal, which is an important precursor to toxic nitrogenous disinfection by-products (N-DBPs). This study aims to evaluate the effects of different carbon source addition on effluent DON concentration, composition, and N-DBP formation potentials. A lab-scale A2O system treating real municipal wastewater was operated with NaAc or SAFL as external carbon sources. DON molecules and potential N-DBP precursors were identified by Orbitrap mass spectrometry. Subsequently, major microorganisms contributing to DON biosynthesis were suggested based on metagenomics. It was found that effluent DON was higher with SAFL as the carbon source than NaAc (1.51 ± 0.24 v.s. 0.56 ± 0.08 mg N/L, p < 0.05). Nevertheless, dichloroacetonitrile and nitrosamine formation potentials (7.14 ± 1.02 and 1.57 ± 0.07 µg/mg DON-N, respectively) of the effluent with SAFL addition were 42.79 ± 2.42% and 54.89 ± 1.70% lower than those of NaAc. Protein- and lignin-like compounds were the most abundant DON molecules in the effluent, where alanine, glycine and tyrosine were important precursors to N-DBPs. Azonexus and Flavobacterium spp. were positively correlated with these precursors, and possessed key genes involved in precursor synthesis. SAFL is a promising carbon source, not only for achieving efficient inorganic nitrogen and DON removals, but also for reducing N-DBP formation potentials of chlorinated effluent.
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Contaminantes Químicos del Agua , Purificación del Agua , Carbono , Desnitrificación , Desinfección , Fermentación , Nitrógeno/análisis , Aguas del Alcantarillado , Aguas Residuales/análisis , Contaminantes Químicos del Agua/análisisRESUMEN
Heterotrophic bacteria grow on influent organics or soluble microbial products (SMP) in wastewater anammox processes, playing key roles in facilitating microbial aggregation and reducing excess nitrate. The overgrowth of heterotrophs represents one of the major causes of anammox process failure, while the metabolic functions of coexisting heterotrophs and their roles in anammox process remain vague. This study aimed at revealing metabolic interactions between AnAOB and active SMP assimilators by integrating 13C DNA-stable isotope probing, metabolomic and metagenomic approaches. Glycine, aspartate, and glutamate with low biosynthetic energy cost were the major SMP components produced by AnAOB (net yield: 44.8, 10.4, 8.1 mg·g NH4+-N-1). Glycine was likely synthesized by AnAOB via the reductive glycine pathway which is oxygen-tolerant, supporting heterotrophic growth. Fermentative Chloroflexi bacterium OLB13, denitrifying Gemmatimonadaceae and Burkholderiaceae bacterium JOSHI-001 were active SMP assimilators, which were prevalent in globally distributed wastewater anammox reactors as core taxa. They likely formed a mutualistic relationship with auxotrophic Ca. Kuenenia by providing necessities such as methionine, folate, 4'-phosphopantetheine, and molybdopterin cofactor, and receiving vitamin B12 for methionine synthesis. For the first time, the identify and metabolic features of SMP assimilators in wastewater anammox communities were revealed. Supplying necessities secreted by heterotrophs could be helpful to the endeavor of AnAOB enrichment. Practically, maintaining active but not overgrown SMP assimilators is critical to efficient and stable operation of wastewater anammox processes.
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Metagenómica , Aguas Residuales , Oxidación Anaeróbica del Amoníaco , Bacterias/metabolismo , Reactores Biológicos/microbiología , ADN/metabolismo , Glicina/metabolismo , Metionina/metabolismo , Nitrógeno/metabolismo , Oxidación-Reducción , Aguas del AlcantarilladoRESUMEN
Complete ammonia oxidizing (comammox) bacteria are frequently detected in wastewater biological nutrient removal (BNR) systems. This study identified "Candidatus Nitrospira nitrosa"-like comammox bacteria as the predominant ammonia oxidizers (97.5-99.4%) in a lab-scale BNR system with acetate and sludge fermentation liquid as external carbon sources. The total nitrogen and phosphorus removals of the system were 75.9% and 86.9% with minimal N2O emission (0.27%). Low ammonia concentration, mixotrophic growth potentials and metabolic interactions with diverse heterotrophs collectively contributed to the survival of comammox bacteria in the system. The recovered draft genomes of comammox bacteria indicated their potentials in using acetate and propionate but not butyrate. Acetate and propionate indeed stimulated the transcription of comammox amoA genes (up-regulated by 4.1 folds compared with no organic addition), which was positively correlated with the ammonia oxidation rate of the community (r = 0.75, p < 0.05). Comammox bacteria could provide vitamins/cofactors (e.g., cobalamin and biotin) to heterotrophs (e.g., Burkholderiaceae), and in return receive amino acids (e.g., phenylalanine and tyrosine) from heterotrophs, which they cannot synthesize. Compared with comammox bacteria, ammonia oxidizing bacteria (AOB) exhibited lower metabolic versatility, and lacked more pathways for the synthesis of amino acids and vitamin/cofactors, leading to their washout in the studied system. BNRs with comammox bacteria as the major nitrifiers hold great potentials in achieving superior performance at low aeration cost and low N2O emission and at full-scale plants.