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1.
Org Lett ; 2020 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-33164517

RESUMO

The synthetically challenging and highly functionalized azabicyclo[6.4.1] ring system, which is found in lycopodium alkaloid lycoclavatumide and some natural molecules, was synthesized for the first time. The key reaction was a diastereoselective type II [5+2] cycloaddition with excellent functional group compatibility. We tried to install the desired eight-membered ring in the final product by RCM reaction.

2.
Intern Emerg Med ; 2020 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-33174152

RESUMO

Patients who experience out-of-hospital cardiac arrest (OHCA) have unacceptably high mortality rates. It remains unclear whether gender has an association with survival in this regard. Hence, we aimed to investigate the association between gender and survival by conducting a systematic review and meta-analysis. The databases of PubMed, Embase, and Cochrane Database of Systematic Reviews were searched from inception to 17 March, 2020. Studies assessing the association between gender and survival to discharge or 30-day survival after OHCA were included. Two reviewers independently assessed the eligibility of the identified studies. The random-effects model was used to pool data, and the outcome was reported as odds ratios (ORs) and 95% confidence intervals, as the relative measure of association. Twenty-three eligible studies enrolling 897,805 patients were included in this systematic review. Overall, women were older and less likely to experience arrest in public places. When arrest occurred, women had less initial shockable rhythm, were less likely to be witnessed by bystanders, and were less likely provided with CPR compared with men. After admission, women underwent less coronary angiography, percutaneous coronary angiography, and targeted temperature management therapy. Eleven studies with ORs were pooled, showing a significant survival benefit in women (OR = 1.08, p < 0.05, I2 = 52.3%). In the subgroup analysis, both premenopausal women (< 50 years) (OR = 1.42, p < 0.001, I2 = 0%) and postmenopausal women (≥ 50 years) (OR = 1.07, p < 0.05, I2 = 16.4%) had higher odds of survival compared with age-matched men. Despite the unfavorable factors, the pooled results showed a significant survival benefit in women after OHCA, especially in premenopausal women.

3.
Artigo em Inglês | MEDLINE | ID: mdl-33174362

RESUMO

Facilitating the dissociation of water and desorption of hydrogen are both crucial challenges for improving the hydrogen evolution reaction (HER) in alkaline media. Herein, we report the synthesis of heterostructure of Ru2P/WO3@NPC (N, P co-doped carbon) by a simple hydrothermal reaction using ruthenium and tungsten salts as precursors, followed by pyrolyzing under an Ar atmosphere. The Ru2P/WO3@NPC electrocatalyst exhibits an outstanding HER activity with an overpotential of 15 mV at a current density of 10 mA·cm-2 and excellent durability in a 1.0 M KOH solution, outperforming state-of-the-art Pt/C and most reported electrocatalysts. Experimental results combined with density functional theory calculations reveal that the electron density redistribution in Ru2P/WO3@NPC is achieved by electron transfer from NPC to Ru2P/WO3 and from Ru2P to WO3, which directly promotes the dissociation of water on W sites in WO3 and desorption of hydrogen on Ru sites in Ru2P.

4.
J Am Chem Soc ; 2020 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-33174722

RESUMO

The first and asymmetric total synthesis of 4ß-acetoxyprobotryane-9ß,15α-diol, containing a rare and highly strained trans-fused bicyclo[3.3.0]octane ring system, has been achieved. The synthetically challenging [6-5-5] tricyclic ring system in the final product was efficiently and diastereoselectively synthesized via an asymmetric rhodium-catalyzed [4 + 2] cycloaddition reaction, followed by a unique benzilic acid type rearrangement under very mild conditions. The seven contiguous stereocenters were installed efficiently and diastereoselectively.

5.
Ultrasound Med Biol ; 2020 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-33187758

RESUMO

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has caused a worldwide pandemic and poses a serious public health risk. It has been proven that lung ultrasound can be extremely valuable in the diagnosis and treatment of the disease, which could also minimize the number of exposed healthcare workers and equipment. Because healthcare workers in ultrasound departments are in close contact with patients who might be infected or virus carriers, it is extremely important that they be provided sufficient protection. Extremely aggressive protection should be avoided because it might lead to a lack of protection equipment for the hospital. Guidance on proper protection management should be provided in detail, for example, how to choose personal protective equipment, how to disinfect the environment. To address these problems, on behalf of the Chinese Ultrasound Doctors Association, Chinese PLA Professional Committee of Ultrasound in Medicine, Beijing Institute of Ultrasound in Medicine and Chinese Research Hospital Association Ultrasound Professional Committee, the authors have summarized the recommendations for effective protection according to existing hygienic standards, their experience and available literature. After the recommendations were completed, two online conferences were held on January 31, 2020 and February 7, 2020, at which the recommendations were discussed in detail. A modified version of the work was circulated and finally approved by all authors, and is the present Chinese Expert Consensus on Protection for Ultrasound Healthcare Workers against COVID-19.

6.
Bioorg Chem ; 104: 104319, 2020 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-33011531

RESUMO

The barks of Magnolia officinalis var. biloba, Magnoliae cortex, have been used as traditional Chinese medicines for several centuries. In this study, phytochemical investigation of M. officinalis var. biloba bark extract afforded five pairs of novel enantiomeric oligomeric neolignans, (±)-mooligomers A-E (1-5). (±)-1 and (±)-2 were two diastereomeric pairs of enantiomers with six C6-C3 subunits, and (±)-4 was a pair of previously unreported tetrameric neolignans bearing eight C6-C3 subunits. (±)-5 is the first example of a naturally occurring trilignan featuring an eight-membered ring with a magnolol moiety. The absolute configurations of (±)-1-(±)-5 were elucidated on the basis of HRESIMS, 1D and 2D NMR spectroscopy and electronic circular dichroism (ECD) calculations. Among the compounds tested for their PTP1B inhibitory activities, (±)-2, (±)-4 and (±)-5 displayed significant PTP1B inhibitory activities with IC50 values of 0.14-2.10 µM. Furthermore, a Molecular docking simulation of PTP1B and active compounds [(±)-2, (±)-4 and (±)-5] exhibited that these active compounds possess low binding affinities ranging from - 5.9 to - 7.7 kcal/mol.

7.
Medicine (Baltimore) ; 99(41): e22523, 2020 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-33031294

RESUMO

There is scarce evidence that the erythrocyte sedimentation rate (ESR) could efficiently improve the prediction accuracy of the Global Registry of Acute Coronary Events (GRACE) risk score in cases of ST-elevation myocardial infarction (STEMI).A cohort of 1094 STEMI patients undergoing primary percutaneous coronary intervention was retrospectively recruited. Patients were categorized based on the ESR values. Final endpoints included cardiovascular death and major adverse cardiovascular event (MACE) occurrence. The predictive value of combined models with the GRACE score and ESR was assessed by receiver operating characteristic (ROC) analysis, net reclassification improvement (NRI), and integrated discrimination improvement.During the mean follow-up of 23 months, 34 patients died and 190 experienced MACEs, of which 23 patients died in the first year; both endpoints were more frequent in the higher group. The ESR and high-sensitivity C-reactive protein (hs-CRP) were independent risk factors of 1-year cardiovascular death, together with the GRACE score (ESR: hazard ratio = 1.03, P = .006 hs-CRP: hazard ratio = 1.00, P = .001; GRACE: 1.03, P = .012). Although no statistical improvement in the area under the ROC curve was observed in either the GRACE/ESR or the GRACE/hs-CRP model (GRACE/ESR models: 0. 8073 vs GRACE: 0.7714, P = .22; GRACE/ESR models: 0. 7815 vs GRACE: 0.7714, P = .61), the GRACE score and ESR together significantly improved the NRI (0.633; P< .001) compared with the GRACE alone. Regarding the mid-term mortality, adding the ESR to the GRACE score not only improved the NRI (0.8433; P < .001), but also increased the integrated discrimination improvement (0.0509; P = .04).The ESR is an independent risk factor of cardiovascular death and MACE in STEMI patients receiving primary percutaneous coronary intervention. The ESR comparatively enhanced the predictive values of the prognostic model, including the GRACE risk score.


Assuntos
Sedimentação Sanguínea , Infarto do Miocárdio com Supradesnível do Segmento ST/sangue , Biomarcadores/sangue , China , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Intervenção Coronária Percutânea , Valor Preditivo dos Testes , Sistema de Registros , Estudos Retrospectivos , Infarto do Miocárdio com Supradesnível do Segmento ST/mortalidade , Infarto do Miocárdio com Supradesnível do Segmento ST/cirurgia
8.
Chem Soc Rev ; 49(19): 7015-7043, 2020 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-32869796

RESUMO

Type II intramolecular cycloadditions ([4+2], [4+3], [4+4] and [5+2]) have emerged recently as an efficient and powerful strategy for the construction of bridged ring systems. In general, type II cycloadditions provide access to a wide range of bridged bicyclo[m.n.1] ring systems with high regio- and diastereoselectivity in an easy and straightforward manner. In each section of this review, an overview of the corresponding type II cycloadditions is presented, which is followed by highlights of method development and synthetic applications in natural product synthesis. The goal of this review is to provide a survey of recent advances in the field covering literature up to 2020. The review will serve as a useful reference for organic chemists engaged in the total synthesis of natural products containing bridged bicyclo[m.n.1] ring systems and provide strong stimulus for invention and further advances in this exciting research field.

9.
Org Lett ; 22(18): 7118-7122, 2020 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-32877199

RESUMO

N-Alkenoxypyridinium salts were found to be highly active electrophilic reagents that could be used to activate the C-N bond of amides. Both aromatic amides and aliphatic amides could be transformed into the corresponding ß-oxo esters with good yields via the combined use of N-alkenoxypyridinium salts and water. The methodology proceeds under mild reaction conditions and is tolerant of various functional groups in both reaction partners.

10.
BMC Cancer ; 20(1): 718, 2020 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-32746784

RESUMO

BACKGROUND: To observe the medium- and long-term clinical efficacy and safety of radioactive 125I seed implantation for refractory malignant tumours based on CT-guided 3D template-assisted technique. METHODS: Twenty-five patients with refractory malignant tumours who underwent radioactive 125I seed implantation based on CT-guided 3D template-assisted technique were selected. The post-operative adverse reactions were recorded. The number of puncture needles and particles used in the operation, dosimetric parameters, post-operative physical strength scores, and tumour response were statistically analysed. The overall survival time and survival rate were calculated, and the effect and prognosis were assessed. RESULTS: 125I seed implantation was successful in all patients without serious complications. The average number of implanted puncture needles was 17 (19.12 ± 13.00), and the median number of particles was 52 (55.12 ± 32.97). D90 in the post-operative clinical target volume (CTV) (93.24 ± 15.70 Gy) was slightly lower than that in the pre-operative CTV (93.92 ± 17.60 Gy; P > 0.05). The D90 in the post-operative planning target volume (PTV) (142.16 ± 22.25 Gy) was lower than the pre-operative PTV (145.32 ± 23.48 Gy; P > 0.05). The tumour responses at 6 months post-operatively: complete remission (CR), 20% (5/25); partial remission (PR), 48% (12/25); stable disease (SD), 24% (6/25); progressive disease (PD), 8% (2/25); CR + PR, 68% (17/25); and local control rate, 92% (23/25). The 6-, 12-, and 24-month survival rates were 100, 88, and 52%, respectively. The post-operative physical strength score (Karnofsky performance score, KPS) exhibited a gradual trend towards recovery, which rose to the highest value 12 months after implantation and then decreased slightly, but the average score was still > 90 points. There was one intra-operative pneumothorax, and two patients with superficial malignant tumours developed skin ulcerations. Multivariate analysis of prognosis showed that tumour sites and types were independent risk factors affecting survival. The number of needles and particles and template types were not the factors. CONCLUSIONS: 3D template combined with CT-guided radioactive 125I seed implantation can improve the rational distribution of radiation dose in the tumour target area because accurate radioactive 125I particle implantation was achieved. This technique has fewer complications and can further extend the overall survival and improve the quality of life. TRIAL REGISTRATION: Registration number: ChiCTR2000034566 2020/7/10 0:00:00 Retrospectively registered.

11.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 37(9): 929-933, 2020 Sep 10.
Artigo em Chinês | MEDLINE | ID: mdl-32820501

RESUMO

OBJECTIVE: To assess the value of single sperm sequencing in preimplantation genetic diagnosis. METHODS: A male patient with achondroplasia due to a de novo FGFR3 variant was subjected to single sperm isolation and sequencing. Twenty single sperm samples were isolated by mechanical immobilization, and their whole genome was amplified. PCR primers were designed for the variant site and 25 flanking single nucleotide polymorphism (SNP) loci, and the PCR products were sequenced to determine the chromosomal haplotype which did not harbor the pathogenic variant. Biopsy samples of 12 embryonic trophoblasts were taken. Following whole genome amplification, high-throughput sequencing was carried out to detect the carrier status of the embryos. Wild type blastocysts were selected for transplantation. Amniotic fluid samples were taken at 19 weeks of gestation to confirm the status of the fetus. RESULTS: Eight SNP were selected by single sperm sequencing, with which the haplotypes were successfully constructed. Preimplantation genetic testing indicated that 5 embryos have carried the pathogenic variant and 7 did not. Testing of amniotic fluid sample during the second trimester of pregnancy confirmed that the fetus did not carry the FGFR3 gene c.1138G>A variant. CONCLUSION: For male patients carrying de novo pathogenic variants, SNP sites can be selected through single sperm sequencing, and haplotypes can be constructed by linkage analysis for preimplantation genetic diagnosis.

12.
Sensors (Basel) ; 20(15)2020 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-32731320

RESUMO

The recognition of non-line-of-sight (NLOS) state is a prerequisite for alleviating NLOS errors and is crucial to ensure the accuracy of positioning. Recent studies only identify the line-of-sight (LOS) state and the NLOS state, but ignore the contribution of occlusion categories to spatial information perception. This paper proposes a bidirectional search algorithm based on maximum correlation, minimum redundancy, and minimum computational cost (BS-mRMRMC). The optimal channel impulse response (CIR) feature set, which can identify NLOS and LOS states well, as well as the blocking categories, are determined by setting the constraint thresholds of both the maximum evaluation index, and the computational cost. The identification of blocking categories provides more effective information for the indoor space perception of ultra-wide band (UWB). Based on the vector projection method, the hierarchical structure of decision tree support vector machine (DT-SVM) is designed to verify the recognition accuracy of each category. Experiments show that the proposed algorithm has an average recognition accuracy of 96.7% for each occlusion category, which is better than those of the other three algorithms based on the same number of CIR signal characteristics of UWB.

13.
Surg Oncol ; 35: 56-61, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32827953

RESUMO

BACKGROUND: Avoiding injury to the external branch of the superior laryngeal nerve (EBSLN) is a major challenge during thyroid surgery. EBSLN injury can have an impact on the quality of life of patients. The aim of this study was to introduce the strap intermuscular approach, to dissect the EBSLN with two different approaches in thyroid surgery, to compare the differences between these two approaches, and to describe a way for surgeons to treat the upper thyroid gland to find the EBSLN. METHODS: A prospective study of hemithyroidectomy was performed. In total, 104 patients were included and randomly divided into two groups: one group used the traditional approach to expose and protect the EBSLN, and the other group used the strap intermuscular approach. We described the surgical procedure for the strap intermuscular approach and compared the differences in the rates of EBSLN exposure, injury, and classification to illustrate the advantages of the intermuscular approach in thyroid surgery. RESULTS: The exposure rate of the EBSLN was higher with the strap intermuscular approach than with the traditional approach (96.15% vs. 76.92%, p = 0.01), with an odds ratio (OR) and 95% confidence interval (CI) of 0.133 (0.028-0.630). The exposure rate of EBSLNs classified as type 1 was higher in the strap intermuscular approach than in the traditional approach (30.77% vs. 13.46%, p = 0.033), with an OR and 95% CI of 0.350 (0.130-0.942). CONCLUSIONS: The exposure rate of the EBSLN was significantly higher with the strap intermuscular approach method than with the traditional approach during thyroid surgery. This approach allows for better identification of the EBSLN during thyroidectomy.

14.
Int J Biol Macromol ; 164: 2795-2803, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32763395

RESUMO

A novel epoxide hydrolase from Glycine max, designated GmEH3, was excavated based on the computer-aided analysis. Then, gmeh3, a GmEH3-encoding gene, was cloned and successfully expressed in E. coli Rosetta(DE3). Among the ten investigated rac-epoxides, GmEH3 possessed the highest and best complementary regioselectivities (regioselectivity coefficients, αS = 93.7% and ßR = 97.2%) in the asymmetric hydrolysis of rac-m-chlorostyrene oxide (5a), and the highest enantioselectivity (enantiomeric ratio, E = 55.6) towards rac-phenyl glycidyl ether (7a). The catalytic efficiency (kcatS/KmS = 2.50 mM-1 s-1) of purified GmEH3 for (S)-5a was slightly higher than that (kcatR/KmR = 1.52 mM-1 s-1) for (R)-5a, whereas the kcat/Km (5.16 mM-1 s-1) for (S)-7a was much higher than that (0.09 mM-1 s-1) for (R)-7a. Using 200 mg/mL wet cells of E. coli/gmeh3 as the biocatalyst, the scale-up enantioconvergent hydrolysis of 150 mM rac-5a at 25 °C for 1.5 h afforded (R)-5b with 90.2% eep and 95.4% yieldp, while the kinetic resolution of 500 mM rac-7a for 2.5 h retained (R)-7a with over 99% ees and 43.2% yields. Furthermore, the sources of high regiocomplementarity of GmEH3 for (S)- and (R)-5a as well as high enantioselectivity towards rac-7a were analyzed via molecular docking (MD) simulation.

15.
Ultrasonics ; 108: 106216, 2020 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-32629150

RESUMO

A single-mode linear ultrasonic motor was developed in this study. On the stator, a group of four pieces of piezoelectric ceramics PZT8 were utilized to generate the ultrasonic vibration. A specially designed modal conversion horn with an oblique beam was applied to transfer the longitudinal vibration to an additional bending vibration. Modal analysis was conducted by finite element method to illustrate the elliptical vibration process. Then the output performance (e.g. output thrust and output velocity) of the motor was evaluated via a series of experiments. The results show that the simulated amplitudes of longitudinal vibration and bending vibration are 9.6 µm and 3.4 µm, respectively, which match well with the tested results. The output thrust increases with the increase of voltage. The largest output thrust is 10 N at the voltage of 600 Vp-p, and the biggest output velocity is 200 mm/s at the supplied frequency of 19.8 kHz and the driving angle of 45°. The output velocity also decreases with the increase of applied load.

16.
J Am Chem Soc ; 142(29): 12602-12607, 2020 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-32658467

RESUMO

The first and asymmetric total synthesis of bioactive bufospirostenin A, an unusual spirostanol with rearranged A/B rings, was accomplished. The synthetically challenging [5-7-6-5] tetracyclic ring system, found in bufospirostenin A and some other natural products, was efficiently constructed by the unique intramolecular rhodium-catalyzed Pauson-Khand reaction of an alkoxyallene-yne. The 11 stereocenters in the final product, including the 10 contiguous stereocenters, were installed diastereoselectively.

17.
J Colloid Interface Sci ; 580: 768-775, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32717443

RESUMO

In this work, controllable hexagonal holes and distributed Er2O3/Er2O3- graphene particles are fabricated on silicon wafers using a straightforward, hydrofluoric, acid-free, and strong alkali-free hydrothermal method. As long as erbium nitrate hydrate and urea coexist in the reaction mixture, silicon wafers can be synthesized successfully using controllable hexagonal hole structures that are regulated by hydrothermal temperature and the addition of graphene oxide and hexadecyl trimethyl ammonium bromide to the reaction mixture. Correspondingly, the wettability of these silicon wafers also is controllable due to the structure that can be changed from hydrophilic (89.3°) to superhydrophobic (153.1°). In short, this work not only provides a simple and nontoxic approach for preparing hexagonal hole structured silicon wafers, but also produces superhydrophobic silicon wafers that potentially can be applied for corrosion-resistant coatings, oil-water separation, and other fields.

18.
Stem Cell Res Ther ; 11(1): 291, 2020 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-32678017

RESUMO

Acute respiratory distress syndrome virus-2 (SARS-CoV-2) responsible for coronavirus disease 2019 (COVID-19) infection, which causes global public health emergencies, has sped widely for more than 5 months and has the risk of long-term transmission. No effective treatment has been discovered to date. In the cases we report, the patient continued to deteriorate even after administration of antiviral drugs such as lopinavir/ritonavir, interferon-α, and ribavirin, as well as intravenous injection of meropenem, methylprednisolone, and immunoglobulin. So, we infused the patient with convalescent plasma (CP), and the absolute lymphocyte count increased the next day and returned to normal on the fourth day. Followed by intravenous infusion of mesenchymal stem cells (MSCs), bilateral infiltrates were absorbed and the pulmonary function was significantly improved. We note that the intravenous infusion of CP and MSCs for the treatment of severe COVID-19 patients may have synergistic characteristics in inhibiting cytokine storm, promoting the repair of lung injury, and recovering pulmonary function. We hope to provide a reference for the research direction of COVID-19 clinical strategies.


Assuntos
Betacoronavirus , Infecções por Coronavirus/terapia , Transplante de Células-Tronco Mesenquimais , Pneumonia Viral/terapia , Idoso , Betacoronavirus/imunologia , Proteína C-Reativa/metabolismo , China , Terapia Combinada , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/fisiopatologia , Citocinas/sangue , Feminino , Humanos , Imunização Passiva , Contagem de Leucócitos , Pulmão/diagnóstico por imagem , Pulmão/fisiopatologia , Neutrófilos , Pandemias , Pneumonia Viral/imunologia , Pneumonia Viral/fisiopatologia , Fenômenos Fisiológicos Respiratórios
19.
Lancet ; 395(10239): 1802-1812, 2020 06 06.
Artigo em Inglês | MEDLINE | ID: covidwho-548644

RESUMO

China has substantially increased financial investment and introduced favourable policies for strengthening its primary health care system with core responsibilities in preventing and managing chronic diseases such as hypertension and emerging infectious diseases such as coronavirus disease 2019 (COVID-19). However, widespread gaps in the quality of primary health care still exist. In this Review, we aim to identify the causes for this poor quality, and provide policy recommendations. System challenges include: the suboptimal education and training of primary health-care practitioners, a fee-for-service payment system that incentivises testing and treatments over prevention, fragmentation of clinical care and public health service, and insufficient continuity of care throughout the entire health-care system. The following recommendations merit consideration: (1) enhancement of the quality of training for primary health-care physicians, (2) establishment of performance accountability to incentivise high-quality and high-value care; (3) integration of clinical care with the basic public health services, and (4) strengthening of the coordination between primary health-care institutions and hospitals. Additionally, China should consider modernising its primary health-care system through the establishment of a learning health system built on digital data and innovative technologies.


Assuntos
Atenção Primária à Saúde/normas , Qualidade da Assistência à Saúde , China , Continuidade da Assistência ao Paciente , Infecções por Coronavirus , Planos de Pagamento por Serviço Prestado , Humanos , Pandemias , Médicos de Atenção Primária/educação , Médicos de Atenção Primária/normas , Pneumonia Viral , Atenção Primária à Saúde/organização & administração
20.
Appl Opt ; 59(16): 4939-4952, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32543491

RESUMO

The Lyot coronagraph is a widely known astronomical instrument used to realize direct imaging of exoplanets, and designing transmittance of an apodizer and Lyot stop is the key to obtaining high-contrast imaging. In this paper a new (to the best of our knowledge) optimization procedure used to design the apodizer and Lyot stop in the Lyot coronagraph is proposed. A two-step optimization program is established to obtain the optimum transmittance of an apodizer and Lyot stop in a sequential way. By using the optimized apodizer and Lyot stop obtained through the proposed optimization procedure, both the stellar light and its diffraction light could be strongly suppressed. Numerical results indicate that such an optimized Lyot coronagraph can produce a 1e-10 extinction of the stellar light near the diffraction limit (1.59λ/D), and a high contrast imaging of 1e-07 could still be obtained even with the influence of light intensity of planets themselves. In addition, the two-step optimization procedure brings in two benefits. First, the two-step optimization is approximately 1000 times faster than the joint optimization method [J. Astron. Telesc. Instrum. Syst.2, 011012 (2016)2329-412410.1117/1.JATIS.2.1.011012]. Second, the optimum transmittance of the Lyot stop is binary, and therefore, the requirements of the production process are reduced, resulting in a greatly reduced cost. At the same time, the performance of the optimized Lyot coronagraph is also analyzed in the case of a monochromatic light incident and bandwidth light incident, and the effect of the diameter of the Lyot stop on the results is also discussed in this paper, which makes sense when designing a coronagraph.

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