RESUMEN
INTRODUCTION: Lung cancer is a major global health problem because of its high incidence and mortality. Targeted therapies have transformed treatment of driver-mutated metastatic non-small cell lung cancer (NSCLC). Nevertheless, recent studies demonstrated that cardiovascular disease (CVD) was the second leading cause of mortality in cancer survivors now, management of patients' cardiovascular health during the course of anticancer therapy has become a great challenge faced by the oncologists. Anticancer related cardiovascular (CV) complications are not limited to traditional chemotherapy, but are also increasingly recognized in targeted therapy. CASE REPORT: We present a case of pulmonary embolism (PE) and bradycardia in a 91-year-old NSCLC patient treated with crizotinib for a rare MET Y1003S mutation. To our knowledge, this is the second report to show antitumor response of crizotinib in lung cancer patients with such a rare mutation. However, the patient complained chest tightness and shortness of breath after a month of standard dose crizotinib therapy. Non-invasive examination revealed new onset bradycardia and PE. MANAGEMENT & OUTCOME: Such clinical manifestations were associated with targeted therapy-related CV toxicity, on which the emerging discipline cardio-oncology focused, and a multidisciplinary investigation and treatment was conducted. DISCUSSION: This case highlights the CV adverse events of novel therapies and the current challenges to be tackled in cardio-oncology.
Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas , Neoplasias Pulmonares , Embolia Pulmonar , Humanos , Anciano de 80 o más Años , Crizotinib/efectos adversos , Carcinoma de Pulmón de Células no Pequeñas/genética , Neoplasias Pulmonares/genética , Mutación , Bradicardia/inducido químicamente , Embolia Pulmonar/inducido químicamente , Inhibidores de Proteínas Quinasas/efectos adversosRESUMEN
Traffic-data recovery plays an important role in traffic prediction, congestion judgment, road network planning and other fields. Complete and accurate traffic data help to find the laws contained in the data more efficiently and effectively. However, existing methods still have problems to cope with the case when large amounts of traffic data are missed. As a generalization of vector algebra, geometric algebra has more powerful representation and processing capability for high-dimensional data. In this article, we are thus inspired to propose the geometric-algebra-based generative adversarial network to repair the missing traffic data by learning the correlation of multidimensional traffic parameters. The generator of the proposed model consists of a geometric algebra convolution module, an attention module and a deconvolution module. Global and local data mean squared errors are simultaneously applied to form the loss function of the generator. The discriminator is composed of a multichannel convolutional neural network which can continuously optimize the adversarial training process. Real traffic data from two elevated highways are used for experimental verification. Experimental results demonstrate that our method can effectively repair missing traffic data in a robust way and has better performance when compared with the state-of-the-art methods.
RESUMEN
Renin-angiotensin system (RAS) signaling has been implicated in the development of cancer. The new RAS ACE2/Ang-(1-7)/Mas axis antagonizes the classical ACE/Ang II/AT1R axis. Ang-(1-7) has pleiotropic roles in lung cancer including suppressing proliferation, angiogenesis, and metastasis. This research was designed to investigate the effect of Ang-(1-7) on tumor-associated angiogenesis in DDP-resistant lung cancer cell lines. We first established acquired DDP-resistant cell lines A549 (A549-DDP) and LLC (LLC-DDP). We next performed RT-qPCR, western blot, ELISA, tube formation, microvessel density detection, immunohistochemistry, and tumor formation assays. The results showed that the mRNA and protein levels of RAS components and vascular endothelial growth factor A (VEGFa) were lessened in the A549/LLC-DDP+Ang-(1-7) group compared with the A549/LLC-DDP group. This effect could be blocked by the MAS receptor antagonist A779. The data revealed that Ang-(1-7) could perform its antiangiogenic function by PI3K/AKT and MAPK pathways. Furthermore, the impact of Ang-(1-7) on tumor-associated angiogenesis has been confirmed in lung cancer xenograft model with acquired DDP resistance. These results provide a theoretical basis for designing therapeutic strategies for targeting Ang-(1-7) in the treatment of NSCLC.
Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas , Neoplasias Pulmonares , Angiotensina I , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Humanos , Neoplasias Pulmonares/tratamiento farmacológico , Fragmentos de Péptidos , Fosfatidilinositol 3-Quinasas , Platino (Metal) , Factor A de Crecimiento Endotelial VascularRESUMEN
Two simply and highly selective aluminium ion fluorescent probes based on 4-aminoantipyrine derivate have been successfully synthesized and systemically characterized, The investigation of absorption and emission spectra revealed that the compounds exhibited highly selective fluorescence behaviours toward Al(3+) in aqueous media and showed differential fluorescent emission peaks corresponding to blue and green. which resulted from different fluorophores, and the fluorescence process is attributed to the Photoinduced Electron Transfer (PET) mechanism, In addition, the association constants between sensors L1 and L2 with aluminum ion are 1.58 × 10(6) M(-1) and 8.72 × 10(6) M(-1), respectively, which were obtained by fluorescent titration experiments. Moreover, the binding site of sensors with Al(3+) were determined by (1)HNMR titration experiments.
RESUMEN
INTRODUCTION: The aim of this study was to compare the efficacy and safety of colistin sulfate (CS) with polymyxin B sulfate (PMB) in the treatment of pneumonia induced by carbapenem-resistant Gram-negative bacteria (CR-GNB). METHODOLOGY: Patients diagnosed with pneumonia caused by CR-GNB and admitted to the intensive care unit (ICU) from January 2020 to September 2022 were enrolled in this study. The patients were divided into the CS group and the PMB group according to their medication regimens. Group-wise demographic data, clinical efficacy, prognosis, and adverse events were analyzed and compared. RESULTS: A total of 120 patients (68 in the CS group and 52 in the PMB group) with pneumonia were included in the study. The majority of the pathogens were CR-Acinetobacter baumannii, followed by CR-Klebsiella pneumoniae, and CR-Pseudomonas aeruginosa. The clinical response rates in the CS and PMB groups after treatment were 62.0% and 65.4%, bacterial clearances were 44.0% and 36.5%, 28-day mortality rates were 16.0% and 13.5%, respectively; no significant differences between the two treatments were found. Nevertheless, the adverse effects were significantly less common in the CS group than in the PMB group, especially when treatments were administered intravenously. CONCLUSIONS: CS, a novel polymyxin E formulation, is as effective as PMB in treating pneumonia induced by CR-GNB while causing less side effects.
Asunto(s)
Antibacterianos , Colistina , Neumonía Bacteriana , Polimixina B , Humanos , Polimixina B/uso terapéutico , Polimixina B/administración & dosificación , Masculino , Colistina/uso terapéutico , Colistina/efectos adversos , Colistina/administración & dosificación , Femenino , Antibacterianos/uso terapéutico , Persona de Mediana Edad , Anciano , Neumonía Bacteriana/tratamiento farmacológico , Neumonía Bacteriana/microbiología , Estudios Retrospectivos , Acinetobacter baumannii/efectos de los fármacos , Infecciones por Bacterias Gramnegativas/tratamiento farmacológico , Resultado del Tratamiento , Adulto , Bacterias Gramnegativas/efectos de los fármacos , Unidades de Cuidados Intensivos , Pseudomonas aeruginosa/efectos de los fármacos , Anciano de 80 o más Años , Klebsiella pneumoniae/efectos de los fármacosRESUMEN
This research compared Portland cement and Phosphogypsum-Steel Slag-Based (PSSB) cement in terms of their capabilities to stabilize heavy metals (specifically lead and nickel) in Oil-Based Drill Cuttings (OBDC). In the experimental section, the qualitative analysis of heavy metal constituents in OBDC was captured by X-ray Photoelectron Spectroscopy (XPS). Additionally, an acetic acid leaching test was implemented for the heavy metal leaching concentration to evaluate the ceramsite stabilization effect on OBDC. In the simulation phase, cement models, heavy metal ion models, and stabilization models were constructed to explore the stabilization mechanism of heavy metals. Results demonstrated that PSSB cement exhibits superior stabilization effects on OBDC compared to Portland cement. Flame Atomic Absorption Spectrophotometry (FAAS) tests showed that PSSB cement reduced Ni and Pb leaching by 21.87 % and 47.32 %, respectively, compared to Portland cement. In PSSB cement, the diffusion coefficients for Ni and Pb ions were observed to decrease by 42.92 % and 79.63 %, respectively, as revealed through Mean Square Displacement (MSD) analysis. The cohesive energy of PSSB cement was 76.73 % lower than that of Portland cement, and its interaction energies for stabilizing Ni and Pb ions were 59.43 % and 76.22 % lower, respectively, demonstrating greater stability and efficiency in metal stabilization. PSSB cement exhibited lower heavy metal concentration and better structural stability than Portland cement.
RESUMEN
Based on the environmental issues of high energy consumption and high emissions of asphalt fumes that are associated with hot mixing asphalt pavement construction, especially with modified asphalt mixtures such as waste rubber modified asphalt (WRMA) mixtures, significant environmentally-friendly new technologies have been successfully applied in the field of asphalt pavement materials. These include fume purification equipment, fume suppression or flame-retarding asphalt mixture, and warm mixing or cold mixing asphalt mixture. This paper provides a comprehensive review of the latest technology in this area regarding both asphalt fume suppression and energy conservation within the last six years. Firstly, asphalt fume suppression technologies in production, laying, and combustion scenarios of an asphalt mixture are identified, and asphalt fume purification equipment utilized in the production process is thoroughly examined. The impacts and mechanisms of various fume suppressants and flame retardants of asphalt fumes regarding their influence on the performance of asphalt pavement are discussed. Secondly, from the perspective of reducing asphalt mixture temperature, different mixing techniques such as cold mixing asphalt (CMA), warm mixing asphalt (WMA), and warm mixing based retarding viscosity asphalt (WM-RVA) are introduced and evaluated utilizing energy consumption and carbon emission evaluation models. These results show that the combination of advanced oxidation and traditional purification methods is critical for promoting the green production of asphalt mixtures. In-depth research on nanomaterials and composite-type asphalt fume suppression materials, WM-RVA, and effective combinations of high-performance modification, recycled materials, fume suppression functional materials, and WMA or CMA hold great promise for future development in this field.
RESUMEN
In the paper, a novel rhodamine6G based fluorescent chemosensor bearing 3-carbaldehyde chromone was designed and synthesized. According to the fluorescence behavior toward several metal ions, it showed highly selectivity and sensitivity to Zn(II) over other commonly coexistent metal ions (Cu(II), Cd(II), Hg(II), Mg(II), K(I), Pb(II), Fe(III) and Cr(III)) in aqueous environment (pH = 7.4). Meanwhile the binding constant between Zn(II) and chemosensor achieved 6.21 × 10(11) M(-1) in aqueous media. Moreover, according to the Job plot, 1:1 stoichiometry between Zn(II) and sensor was deduced in aqueous media (pH = 7.4). The good selectivity and sensitivity in aqueous media effectively enhanced the application value of the fluorescent chemosensor for Zn(II).
Asunto(s)
Colorantes Fluorescentes/química , Rodaminas/química , Zinc/análisis , Colorantes Fluorescentes/síntesis química , Iones/análisis , Modelos Moleculares , Estructura Molecular , Rodaminas/síntesis química , Espectrometría de Fluorescencia , Agua/químicaRESUMEN
A decoupling method is proposed for micro-Newton thrust measurement with a torsion pendulum. The basic approach is to reduce the influences introduced by the propellant tube and wires of the thruster. A hollow aluminum tube is used to hang the torsion pendulum and is also chosen as the transport pipe for the propellant of the thruster. The electric control box of the thruster is mounted on the pendulum body, which is powered by an externally installed power supply through a liquid metal conductive unit. The control of the electric control box is performed through wireless transmission. With this design, the influences of the propellant tube and connection wires between the torsion pendulum and the outside device are reduced and the stability of the torsion spring constant of the system can be improved. The use of the liquid metal conductive unit reduces the coupling between the wires and the measurement system. The feasibility of the wireless transmission is analyzed. The error sources during the thrust measurement are analyzed, and the expected three σ uncertainty of the thrust is 0.032+(0.10%*F)2µN for the measurement of the cold gas thruster. The scheme provides a thrust measurement with higher precision and stability.
RESUMEN
Background: The usefulness of metagenomic next-generation sequencing (mNGS) in identifying pathogens is being investigated. We aimed to compare the power of microbial identification between mNGS and various methods in patients with acute respiratory failure. Methods: We reviewed 130 patients with respiratory failure, and 184 specimens including blood, bronchoalveolar lavage fluid (BALF), sputum, pleural effusion, ascitic fluid, and urine were tested by mNGS and conventional methods (culture, PCR). We also enrolled 13 patients to evaluate the power of mNGS and pathogen targets NGS (ptNGS) in microbial identifications. Clinical features and microbes detected were analyzed. Results: mNGS outperformed the conventional method in the positive detection rate of Mycobacterium tuberculosis (MTB) (OR, ∞; 95% CI, 1-∞; P < 0.05), bacteria (OR, 3.7; 95% CI, 2.4-5.8; P < 0.0001), fungi (OR, 4.37; 95% CI, 2.7-7.2; P < 0.0001), mycoplasma (OR, 10.5; 95% CI, 31.8-115; P = 0.005), and virus (OR, ∞; 95% CI, 180.7-∞; P < 0.0001). We showed that 20 patients (28 samples) were detected with Pneumocystis jirovecii (P. jirovecii) by mNGS, but not by the conventional method, and most of those patients were immunocompromised. Read numbers of Klebsiella pneumoniae (K. pneumoniae), Acinetobacter baumannii (A. baumannii), Pseudomonas aeruginosa (P. aeruginosa), P. jirovecii, cytomegalovirus (CMV), and Herpes simplex virus 1 (HSV1) in BALF were higher than those in other sample types, and the read number of Candida albicans (C. albicans) in blood was higher than that in BALF. We found that orotracheal intubation and type 2 diabetes mellitus (T2DM) were associated with a higher detection rate of bacteria and virus by mNGS, immunosuppression was associated with a higher detection rate of fungi and virus by mNGS, and inflammatory markers were associated with mNGS-positive detection rate of bacteria. In addition, we observed preliminary results of ptNGS. Conclusion: mNGS outperformed the conventional method in the detection of MTB, bacteria, fungi, mycoplasma, and virus. Orotracheal intubation, T2DM, immunosuppression, and inflammatory markers were associated with a higher detection rate of bacteria, fungi, and virus by mNGS. In addition, ptNGS results were consistent with the detection of abundant bacteria, fungi, and mycoplasma in our specimens.
Asunto(s)
Diabetes Mellitus Tipo 2 , Mycobacterium tuberculosis , Insuficiencia Respiratoria , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Mycobacterium tuberculosis/genética , Sensibilidad y EspecificidadRESUMEN
Saliva is abundant with proteins, metabolites, DNA, and a diverse range of bacterial species. During the past two decades, saliva has emerged as a novel diagnostic and evaluation medium for several diseases. Collection of saliva samples is simple, minimally invasive, and convenient even in infants, children, and patients with anxious. Furthermore, with the development of hypersensitive techniques [e.g., microsensor arrays, enzyme-labeled immunosensors, nanoparticle-labeled immunosensors, capacitive or impedimetric immunosensors, magneto immunosensors, field effect transistor immunosensors, and surface enhanced Raman spectroscopy (SERS)], the sensitivity and accuracy of saliva diagnostic procedures have been improved. Nowadays, saliva has been used as a potential medium for several disease diagnosis and assessment, such as periodontitis, caries, cancers, diabetes mellitus, and cardiovascular diseases. Saliva has been used widely for studying microbiomics, genomics, transcriptomics, proteomics, and metabolomics of respiratory diseases, however, the use of salivary biomarkers for the diagnosis, prognosis, and monitoring of respiratory disease is still in its infancy. Herein, we review the progress of research on salivary biomarkers related to several respiratory diseases, including bronchial asthma, chronic obstructive pulmonary disease (COPD), obstructive sleep apnea (OSA), pneumonia, tuberculosis (TB), Langerhans cell histiocytosis (LCH) and cystic fibrosis (CF). Furthermore, several limitations of saliva test such as the lack of standard protocol for saliva collection and reasonable reference values for saliva test are also mentioned in this review.
RESUMEN
In the heteronuclear coordination polymer, {[CuNa(C(9)H(2)NO(8))(H(2)O)(7)]·4H(2)O}(n), the Cu(II) atom is coordinated by six O atoms from five water mol-ecules and one 5-nitro-benzene-1,2,3-tricarboxyl-ate ligand in a slightly distorted octa-hedral geometry. The Na(+) cation is surrounded by six water mol-ecules in an irregular trigonal-prismatic geometry. The Cu and Na atoms are connected by water bridges, forming an infinite chain. O-Hâ¯O hydrogen bonds involving the coordinated and uncoordinated water mol-ecules connect the chains into a three-dimensional network.
RESUMEN
In the crystal of the title compound, C(15)H(11)ClN(2)O, the molecules are linked by C-Hâ¯O and weak C-Hâ¯π inter-actions. The chloro-phenyl and phenyl rings are twisted with respect to the central pyrazolone ring, making dihedral angles of 18.23â (8) and 8.35â (8)°, respectively. The N-N and C=O bond lengths are comparable to those reported for pyrazolone compounds.
RESUMEN
The application of photocatalyst in pavements has received comprehensive attention in recent years due to its ability to decontaminate nitrogen oxides (NOx). However, it's remarkable that NOx also accumulated extensively in parking lots. The purpose of this study is to develop a movable photocatalytic plate (remarked photocatalytic KT plates) coupled with high activity to purify NOx. Firstly, the type of photocatalytic KT plates was determined according to NO removal experiment in laboratory. Then the plates were employed in the parking lots for removing NOx. One sample T-test, normality test and paired sample T-test methods for NOx concentration variation were conducted to determine the appropriate comparative means of dates under both dark and illuminated conditions. The difference of NOX concentration between dark and illuminated conditions was obtained to evaluate the photocatalytic removal efficiency. The results indicated that NO removal efficiency in laboratory and parking lots were 51.31% and 9.2%, respectively.
Asunto(s)
Grafito/química , Compuestos de Nitrógeno/química , Estacionamientos , Titanio/química , Catálisis , Ciudades , Luz , Óxido Nítrico/aislamiento & purificaciónRESUMEN
In this study, we present a case of 65-year-old male patient with suspected Sjögren's syndrome-related interstitial lung disease (SS-ILD) with initial symptoms of limb edema and acute respiratory failure. He was treated with immunosuppressor, respiratory support, dialysis, immunomodulatory, and anti-inflammatory medications. However, no significant response was shown to anti-fibrotic treatments and his respiratory function deteriorated. Double lung transplantation was thus indicated considering the irreversible interstitial changes in both lungs. The surgical procedure was complicated, and the role of enhanced recovery after surgery (ERAS) for this critical patient was discussed. The patient experienced hemorrhage, pulmonary infection, and peripheral neuropathy after surgery, but he was cured by the multidisciplinary team. He had a satisfactory quality of life at 1-year follow-up. This case report describes the details of double lung transplantation in a patient with advanced SS-ILD. Important considerations include the indications for and timing of transplantation, the effects of long-term immunosuppression on wound healing, and extrapulmonary organ dysfunction. Based on a review of the published literature and a consideration of the short-term outcomes, lung transplantation for this individual with an autoimmune disease appears to be safe and feasible. SS-ILD should not be a contraindication to transplantation; however, patients with advanced pulmonary involvement should be carefully selected after a multidisciplinary evaluation. More long-term follow-up and further comparative studies are needed in the future.
RESUMEN
Background: Pulmonary fat embolism (PFE) is one of the important causes of acute lung injury (ALI), but its pathogenesis is unclear. In recent years, it has been found that the NLRP3 inflammasome is closely related to inflammatory response. However, there are no reports about the involvement of NLRP3 in PFE- associated ALI. Glibenclamide is a kind of hypoglycaemic drug with anti-inflammatory effect. It has been reported to have the anti-inflammatory effect related to inhibiting NLRP3. Objective: To determine whether NLRP3 inflammasome was involved in ALI induced by PFE or whether glibenclamide had therapeutic effects on such lung injury, we designed this experiment. Materials and methods: The rat model of intravenous injection of oleic acid (OA) was used to simulate PFE. Rats were divided into three groups: control, OA and glibenclamide treatment group. Blood free fatty acid (FFA) concentration was determined by ACS-ACOD. Histopathological examinations were taken to assess the severity of lung injury. The expression of NLRP3 pathway and its downstream products were analyzed by IHC, WB, qPCR and ELISA. Results: Four hours after intravenous OA injection, the typical pathological manifestations of ALI accompanied by elevated levels of plasma FFAs were found. The activity of NLRP3 inflammasomes increased in OA group, too. Pretreatment with glibenclamide partly inhibited the increase in NLRP3, caspase-1 and IL-1ß expression induced by OA, simultaneously attenuated the lung injury. But it has little effect on the expression of Toll-like receptor 4 (TLR4) expression in this experiment. Conclusion: NLRP3 inflammasome, one of the main components of innate immune response, involved in ALI induced by OA. Glibenclamide can alleviate this kind of ALI by inhibiting rather the NLRP3/caspase-1/IL-1ß signaling pathway than the levels of FFAs or TLR4 pathway.
Asunto(s)
Lesión Pulmonar Aguda/tratamiento farmacológico , Gliburida/farmacología , Inflamasomas/efectos de los fármacos , Inflamación/tratamiento farmacológico , Proteína con Dominio Pirina 3 de la Familia NLR/antagonistas & inhibidores , Lesión Pulmonar Aguda/inducido químicamente , Lesión Pulmonar Aguda/patología , Animales , Modelos Animales de Enfermedad , Inflamasomas/metabolismo , Masculino , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Ácido Oléico , Estrés Oxidativo/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Transducción de Señal/efectos de los fármacosRESUMEN
The catalytic (SBA-15, Ni/SBA-15, Al/SBA-15 and Ni-Al/SBA-15) hydrothermal liquefaction (HTL) of rice straw biomass was examined at different temperature with different amount of catalyst in the presence of different solvents. In comparison with water solvent liquefaction, the bio-oil yield significantly increased under alcoholic solvent (ethanol and methanol). The highest bio-oil yield was observed for water (44.3â¯wt%) with Ni-Al/SBA-15, while for ethanol (56.2â¯wt%), and for methanol (48.1â¯wt%) with, Ni/SBA-15 catalyst. The loading of Ni and Al on SBA-15, the acid strength of the catalyst enhanced. Bio-oils yield were analyzed with the help of GC-MS, FT-IR, NMR, GPC and CHNS. From the GC-MS analysis, the main monomeric phenolic compounds were produced, phenol, 4-ethyl-phenol, 2-methoxy-phenol, 2-methoxy-4-ethyl-phenol and Vanillin. It was observed by CHNS and GPC analysis of the bio-oil, compared to the non-catalytic liquefaction reaction, the catalytic liquefaction reaction promotes the hydrogenation/hydrodeoxygenation and produced lower molecular weight bio-oils.
Asunto(s)
Oryza , Fenol , Biocombustibles , Biomasa , Metales , Fenoles , Espectroscopía Infrarroja por Transformada de Fourier , Temperatura , AguaRESUMEN
Rh/γ-Al2O3 catalysts were synthesized by both incipient wetness impregnation (IWI) and atomic layer deposition (ALD). The TEM images of the two catalysts showed that the catalyst from ALD had smaller particle size, and narrower size distribution. The surface chemical states of both catalysts were investigated by both XPS and X-ray Absorption Near Edge Structure (XANES), and the catalyst from IWI had higher concentration of Rh3+ than that from ALD. The catalytic performance of both catalysts was tested in the dry reforming of methane reaction. The catalyst from ALD showed a higher conversion and selectivity than that from IWI. The stability testing results indicated that the catalyst from ALD showed similar stability to that from IWI at 500 °C, but higher stability at 800 °C.
RESUMEN
The plants in the genus Gardenia (Rubiaceae) have long been used as traditional medicines in China. In this study, two new 3,4-seco-cycloartane triterpenes, sootepin J (1) and sootepin K (2), and a novel nor-3,4-seco-cycloartane triterpenes, sootepin L (3), together with two known compounds (4-5), were isolated from the methanolic extract of the leaves and twigs of Gardenia sootepensis. The structures of the new compounds were elucidated by combinations of 1D, 2D NMR experiments and HR-MS data, while the known compounds were identified by comparison of the NMR data with previously published data.
Asunto(s)
Gardenia/química , Triterpenos/aislamiento & purificación , China , Estructura Molecular , Hojas de la Planta/química , Análisis Espectral , Triterpenos/químicaRESUMEN
The use of a filter is the most common method to suppress low-frequency discharge current oscillation in Hall thrusters. The only form of filter in actual use involves RLC networks, which serve the purpose of reducing the level of conducted electromagnetic interference returning to the power processing unit, which is the function of a filter. Recently, the role of the filter in the oscillation control was introduced. It has been noted that the filter regulates the voltage across itself according to the variation of discharge current so as to decrease its fluctuation in the discharge circuit, which is the function of a controller. Therefore, a kind of two-stage filter is proposed to fulfill these two purposes, filtering and controlling, and the detailed design methods are discussed and verified. A current oscillation attenuation ratio of 10 was achieved by different capacitance and inductance combinations of the filter stage, and the standard deviation of low-frequency oscillations decreased from 3 A-1 A by the control stage in our experiment.