Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 758
Filtrar
1.
Acta Neurol Belg ; 2020 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-33219489

RESUMO

Visuoexecutive impairment is common among acute ischemic stroke patients. This study aimed to examine the ability of the Montreal Cognitive Assessment (MoCA) and Mini-Mental State Examination (MMSE) visuoexecutive subtests to detect visuoexecutive abnormality in acute ischemic stroke patients and to identify the predictors for their impairments. 336 patients who completed the MMSE and MoCA were enrolled in this study. We compared the proportion of participants with incorrect MoCA visuoexecutive tasks and MMSE pentagon copying. Multivariate logistic regression analysis was used to evaluate the associations between the visuoexecutive dysfunction and demographic and clinical characteristics in the samples. Among all the participants, the MoCA detected more visuoexecutive dysfunction than the MMSE (88.69% vs. 45.83%, respectively; p < 0.001). The predictors identified by the univariate analysis included the factors of gender, age, educational level, smoking, alcohol consumption, Oxfordshire Community Stroke Project (OCSP), previous strokes, initial NIHSS score and number of old lacunar infarctions, while from the multivariate logistic regression analysis, the factors of age, educational level, NIHSS score, previous strokes and number of old lacunar infarctions served as predictive factors for the visuoexecutive impairment in acute stroke patients. In conclusion, visuoexecutive impairment is associated with the factors of the educational level, stroke severity, stroke history and number of old lacunar infarctions. Our findings may guide the clinicians to intervene the risks for the patients at an early stage after stroke and form the basis for good rehabilitation plans.

2.
J Microbiol ; 2020 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-33201433

RESUMO

Gloeostereum incarnatum is an edible medicinal mushroom widely grown in China. Using the whole genome of G. incarnatum, simple sequence repeat (SSR) markers were developed and synthetic primers were designed to construct its first genetic linkage map. The 1,048.6 cm map is composed of 10 linkage groups and contains 183 SSR markers. In total, 112 genome assembly sequences were anchored, representing 16.43 Mb and covering 46.41% of the genome. Selfing populations were used for quantitative trait loci (QTL) targeting, and the composite interval mapping method was used to co-localize the mycelium growth rate (potato dextrose agar and sawdust), growth period, yield and fruiting body length, and width and thickness. The 14 QTLs of agronomic traits had LOD values of 3.20-6.51 and contribution rates of 2.22-13.18%. No linkage relationship was found between the mycelium growth rate and the growth period, but a linkage relationship was observed among the length, width and thickness of the fruiting bodies. Using NCBI's BLAST alignment, the genomic sequences corresponding to the QTL regions were compared, and a TPR-like protein candidate gene was selected. Using whole-genome data, 138 candidate genes were found in four sequence fragments of two SSR markers located in the same scaffold. The genetic map and QTLs established in this study will aid in developing selective markers for agronomic traits and identifying corresponding genes, thereby providing a scientific basis for the further gene mapping of quantitative traits and the marker-assisted selection of functional genes in G. incarnatum breeding programs.

3.
J Int Med Res ; 48(10): 300060520962296, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33081537

RESUMO

OBJECTIVES: To investigate the clinical and drug resistance characteristics of Providencia stuartii infections in the Huainan region of Anhui and provide a reference for the clinical selection of antimicrobial agents. METHODS: This single-center retrospective analysis included 76 patients with P. stuartii infection in Huainan during the period from October 2018 to March 2020. The hospital department in which the patients were treated and the drug susceptibility characteristics of the P. stuartii isolates were recorded. RESULTS: Among the 76 patients, the lung was the most common site of infection, and intensive care unit was the main hospital department. Extended spectrum beta-lactamase screening revealed expression by all 76 isolates of P. stuartii. Of the 76 isolates, 92.1% exhibited multiple drug resistance or extensive drug resistance. P. stuartii isolates were sensitive to cefepime and imipenem, but not to other beta-lactam antibiotics. Twenty isolates were resistant to all 21 types of antibiotics. Of the 20 patients infected with extensively drug-resistant isolates, nine (45%) died. CONCLUSIONS: Drug resistance is increasing in P. stuartii. The antimicrobial agent imipenem may be effective for treatment of P. stuartii infections. Fluoroquinolones, aminoglycosides, and fourth-generation cephalosporins are suitable options for antibiotic therapy.

4.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 232-235, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33017971

RESUMO

A 24GHz Doppler radar system for accurate contactless monitoring of heart and respiratory rates is demonstrated here. High accuracy predictions are achieved by employing a CNN+LSTM neural network architecture for regression analysis. Detection accuracies of 99% and 98% have been attained for heart rate and respiration rate, respectively.Clinical Relevance- This work establishes a non-contact radar system with 99% detection accuracy for a heart rate variability warning system. This system can enable convenient and fast monitoring for daily care at home.


Assuntos
Algoritmos , Redes Neurais de Computação , Frequência Cardíaca , Respiração , Taxa Respiratória
6.
Genet Sel Evol ; 52(1): 59, 2020 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-33036552

RESUMO

BACKGROUND: Genetic analysis of gene expression level is a promising approach for characterizing candidate genes that are involved in complex economic traits such as meat quality. In the present study, we conducted expression quantitative trait loci (eQTL) and allele-specific expression (ASE) analyses based on RNA-sequencing (RNAseq) data from the longissimus muscle of 189 Duroc × Luchuan crossed pigs in order to identify some candidate genes for meat quality traits. RESULTS: Using a genome-wide association study based on a mixed linear model, we identified 7192 cis-eQTL corresponding to 2098 cis-genes (p ≤ 1.33e-3, FDR ≤ 0.05) and 6400 trans-eQTL corresponding to 863 trans-genes (p ≤ 1.13e-6, FDR ≤ 0.05). ASE analysis using RNAseq SNPs identified 9815 significant ASE-SNPs in 2253 unique genes. Integrative analysis between the cis-eQTL and ASE target genes identified 540 common genes, including 33 genes with expression levels that were correlated with at least one meat quality trait. Among these 540 common genes, 63 have been reported previously as candidate genes for meat quality traits, such as PHKG1 (q-value = 1.67e-6 for the leading SNP in the cis-eQTL analysis), NUDT7 (q-value = 5.67e-13), FADS2 (q-value = 8.44e-5), and DGAT2 (q-value = 1.24e-3). CONCLUSIONS: The present study confirmed several previously published candidate genes and identified some novel candidate genes for meat quality traits via eQTL and ASE analyses, which will be useful to prioritize candidate genes in further studies.

7.
J Urol ; : 101097JU0000000000001406, 2020 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-33026927

RESUMO

PURPOSE: To demonstrate the generalizability of PRECISION findings and apply the PRECISION biopsy strategy to a contemporary cohort to characterize cancers missed by employing this strategy. MATERIALS AND METHODS: 629 men biopsied between 2/2015-9/2018 met PRECISION inclusion criteria. Men with PI-RADS 1-2 MRI were only biopsied if high clinical suspicion for cancer. Missed cancers were defined as prostate cancer (PCa) identified uniquely on systematic biopsy (SB) in men with PI-RADS 3-5 MRI, or on either SB or MRI-targeted prostate biopsy (MRI-TB) in men with PI-RADS 1-2 MRI. Outcomes included 1) clinically-significant PCa (csPCa), ≥Gleason grade group (GG) 2, detection rate (CDR), 2) missed csPCa rate upon application of PRECISION biopsy strategy, 3) GG distribution, core size, spatial orientation, and oncologic risk among missed cancers. RESULTS: Application of the PRECISION biopsy strategy to the study cohort resulted in avoidance of biopsy in 28%, similar MRI-TB CDR to PRECISION, reduction of GG1 CDR by 60%, and reduction of csPCa CDR by 19%. Missed csPCa were often <6 mm (54.5%), GG2 (67.3%), and low-risk by clinical nomogram (74.6%). GG1 cancers identified uniquely on SB were often contralateral to MRI target (46.4%), while missed csPCa was predominantly ipsilateral (81%). Limitations include biopsy of only men with high-risk clinical features among PIRADS 1-2 MRI, potentially overestimating the csPCa CDR. CONCLUSIONS: The study cohort demonstrated generalizability of PRECISION findings. Applying the PRECISION biopsy strategy greatly reduces GG1 CDR, while missing a small number of csPCa, typically small volume, low-risk, and GG2. Missed csPCa are predominantly ipsilateral to MRI target, possibly representing targeting error.

8.
J Urol ; : 101097JU0000000000001424, 2020 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-33080145

RESUMO

PURPOSE: A benign MRI-targeted prostate biopsy (MRF-TB) in the setting of a PI-RADS 4/5 abnormality presents a clinical dilemma for future management. We evaluated benign histologic features on MRF-TB to determine if they predict the likelihood of missed cancer on subsequent biopsy. MATERIALS AND METHODS: Between 6/2012 and 9/2016, 1595 men were enrolled in a prospective study of MRI-targeted and systematic biopsy outcomes. We re-reviewed pathology from benign MRF-TB of PI-RADS 4/5 abnormalities and divided into 5 groups for comparison to outcomes of clinical follow-up: inflammation (38%), stroma/glandular hyperplasia (9%), normal prostate tissue (28%), ASAP/HGPIN (9%), and cancer in adjacent systematic cores (16%). RESULTS: 88/497 (18%) men with PI-RADS 4/5 abnormality prior to initial biopsy had no cancer on MRF-TB. In follow-up, 45 men underwent repeat MRI: 12 (27%) had persistent PI-RADS 4/5 abnormalities, 17 (38%) had PI-RADS 2/3, 16 (35%) had PI-RADS 1. On repeat MRF-TB, cancer was found in 62.5% of men with PI-RADS 4/5 and 23% of men with PI-RADS 2/3. Histologic groups on initial MRF-TB were not predictive of the likelihood of PI-RADS downgrade on repeat MRI or cancer detection on repeat biopsy. CONCLUSIONS: Among men with no cancer on MRF-TB performed for PI-RADS abnormality, downgrade of PI-RADS score is noted in 73% on repeat MRI. Persistence of PI-RADS 4/5 predicts a higher risk of missed cancer, warranting prompt re-biopsy. While histologic findings such as inflammation may underlie some PI-RADS 4/5 abnormalities, initial histology is a poor predictor of cancer likelihood on repeat biopsy.

10.
Breast ; 54: 52-55, 2020 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-32919172

RESUMO

The breast cancer screening program has continued in Taiwan during the COVID-19 pandemic. Our nationwide data showed that the total number of screenings decreased by 22.2%, which was more pronounced for in-hospital examinations (-37.2%), while outreach showed a 12.9% decrease. This decline in screening participation happened at all levels of hospitals, more significantly at the highest level. Our report revealed that outreach services could maintain relatively stable breast cancer screening under this kind of public health crisis. Building a flexible, outreach system into the community might need to be considered when policymakers are preparing for future possible pandemics.

11.
Oncol Res Treat ; 43(11): 573-583, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32957100

RESUMO

BACKGROUND AND OBJECTIVE: The aim of this study was to investigate the value of programmed death ligand 1 (PD-L1) expression as a predictive biomarker for Miller/Payne grading before neoadjuvant chemotherapy (NACT) in breast cancer. PATIENTS AND METHODS: The expression of PD-L1 in pretreatment biopsies of breast cancer was assessed by immunohistochemistry in tissue microarrays. The results were analyzed using SPSS 22.0 statistical software. RESULTS: Of 53 female patients, 10 (18.9%) patients had a grade 5 (G5) response, and 12 (22.6%) patients showed PD-L1 expression, including 7 (13.2%) patients with staining in tumor cells (TCs) and 8 (15.1%) patients with staining in peritumoral lymphocytes (PTLCs). Logistic regression analysis revealed that G5 response to NACT was significantly associated with TCs or PTLCs PD-L1 positivity, whether with univariate analysis (TCs PD-L1: p = 0.00, OR 20.50, 95% CI 3.11-134.94; PTLCs PD-L1: p = 0.02, OR 6.50, 95% CI 1.27-33.20) or with multivariate analysis (TCs PD-L1: p = 0.00, OR 42.23, 95% CI 3.36-530.90; PTLCs PD-L1: p = 0.02, OR 9.07, 95% CI 1.37-60.02). The same trend was found in the luminal subgroup analysis (TCs PD-L1: p = 0.02, OR 23.43, 95% CI 1.66-331.58; PTLCs PD-L1: p = 0.01, OR 47.89, 95% CI 2.47-927.41). CONCLUSION: G5 response to NACT in breast cancer was significantly associated with TCs or PTLCs PD-L1-positive expression in pretreatment biopsies; it can be expected that PD-L1 will become a new independent biomarker of response to NACT in breast cancer.

13.
Zhongguo Gu Shang ; 33(8): 735-40, 2020 Aug 25.
Artigo em Chinês | MEDLINE | ID: mdl-32875764

RESUMO

OBJECTIVE: To explore the clinical efficacy of C3 expanded half lamina excision combined with unilateral open door laminoplasty for multiple segmental cervical spinal cord compression syndrome. METHODS: The clinical data of 58 patients with multiple segmental cervical spinal cord compression syndrome underwent surgical treatment between September 2014 and May 2018 were retrospectively analyzed. There were 34 males and 24 females with a mean age of 64.4 years old (ranged from 46 to 78 years old). Among them, 28 cases received the surgery of C3 expanded half lamina excision combined with C4-C7 unilateral open-door laminoplasty (improvedgroup), and 30 cases received a single C3-C7 unilateral open-door laminoplasty (traditional group). Operation time, intraoperative blood loss, complications including C5 nerve root palsy and axial symptoms were compared between two groups. To evaluate the situation of the imaging indicators by measuring the space available for the spinal cord through cross sectional MRI of cervical spine at the narrowest segment of C3 (including intervertebral disc levels of C3, 4). Pre- and post-operative Japanese Orthopedic Association(JOA) score, Neck Disability Index(NDI) score, and improvement rate of neurological function, were recorded and analyzed between the two groups. RESULTS: All the patients were followed up for 12 to 18 months with an average of(14.5±1.8) months for improved group and (14.5±1.9) months for traditional group, and no significant difference was found between the two groups (P>0.05). There was no significant difference in intraoperative blood loss and C5 nerve root palsy between the two groups (P>0.05). The operation time (119±10) min vs (126±12) min and axial symptoms 7.1%(2/28) vs 26.6%(8/30) was significant difference between the two groups (P<0.05). Preoperative and postoperative space available for the spinal cord of C3 was (93.61±9.02) mm3 and (153.50±12.76) mm3 respectively, which was obtained obvious improvement in all patients(P<0.05). At the final follow up, JOA scores of improved group and traditional group were 14.36±1.70 and 14.03±1.82 respectively, and NDI scores were 10.36±2.55 and 12.47±3.46 respectively, there was significant difference between two groups (P<0.05). However, there was no significant difference between two groups for the improvement rate (68.36±0.12)%VS (65.01±0.12)%of neurological function(P>0.05). CONCLUSION: C3 expanded half lamina excision combined with unilateral open-door laminoplasty is an effective method to treat multiple segmental cervical spinal cord compression syndrome, for it can not only fully relieved spinal cord compression, but also achievedgood effect in preventing complications such as axial symptoms by reducing stripping of muscles from C2 spinous process.


Assuntos
Laminoplastia , Compressão da Medula Espinal , Idoso , Vértebras Cervicais/cirurgia , Estudos Transversais , Feminino , Humanos , Laminectomia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Resultado do Tratamento
14.
J Hazard Mater ; 399: 123081, 2020 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-32937717

RESUMO

Elimination of U(VI) from polluted solutions is important for human health and environmental safety. In this work, a relatively low-cost 3D flower-like phosphate-functionalized layered double hydroxides (phos-LDH) was fabricated by a one-pot hydrothermal method. The prepared phos-LDH inherited the structure of 3D flower-like layered double hydroxides (LDH), and had a higher specific surface area (∼203.4 m2⋅g-1) than that of LDH. The kinetic process indicated that U(VI) adsorption onto phos-LDH achieved equilibrium within 15 min and obeyed general order model. The adsorption isotherms of phos-LDH illustrated that the U(VI) adsorption obeyed Langmuir model, the adsorption capability of phos-LDH can reach 923.1 mg⋅g-1 at 298 K. The U(VI) adsorption was a spontaneous and endothermic process according to the thermodynamic data. There was the electrostatic attraction between U(VI) and phos-LDH at pH = 5.0. FTIR and XPS analyses educed that the hydroxyl and phosphate groups played a very useful role for the complexation between U(VI) and phos-LDH. In addition, the excellent selective adsorption capability for U(VI) in competitive cation and anion solutions further confirmed the practical application of phos-LDH in real wastewater treatment.

15.
Brain Behav ; 10(11): e01806, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32856405

RESUMO

OBJECTIVE: The clock-drawing test (CDT) is a widely used screening tool for detecting cognitive decline. However, normative data for Chinese individuals are scarce. Our study aimed to provide standardized values for the three quantitative CDT scoring methods that were tailored for Chinese-speaking adults in Shijiazhuang City and explore the discriminant validity of the CDT scores in patients with acute ischemic stroke. METHODS: We conducted the CDT among 418 healthy individuals aged between 35 and 84 years. The CDT was administered and scored by five raters using the method derived from the Montreal Cognitive Assessment (MoCA), Rouleau's, and Babins' scoring systems. The influence of age, education, and sex on the performance in the CDT was analyzed. Furthermore, 336 patients with acute ischemic stroke were enrolled to explore the discriminant validity of CDT scores. RESULTS: In all three scoring systems, CDT scores were significantly correlated with age and years of education but not with sex. Normative data stratified for age and years of education were established. Interrater and intersystem reliability were high in our study. CDT total scores and subscores showed significant differences between stroke patients and healthy individuals. CONCLUSIONS: Our study provides CDT normative data using three quantitative scoring methods for Chinese-speaking adults in Shijiazhuang City. Age and education level were the key factors that affected the CDT scores. CDT total scores and subscores provided good discriminant validity for patients with acute ischemic stroke.

16.
J Cell Mol Med ; 24(19): 11546-11557, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32845082

RESUMO

We aimed to investigate the role of the miR-29b and its effect on TGF-ß3 pathway in vascular and valvular calcification in a rat model of calcific aortic valve diseases (CAVD). A rat model of CAVD was established by administration of warfarin plus vitamin K. The expression levels of miR-29b, osteogenic markers and other genes were determined by qRT-PCR, Western blot and/or immunofluorescence and immunohistochemistry. The calcium content and alkaline phosphatase (ALP) activity were measured. The calcium content, ALP activity and osteogenic markers levels in calcified aorta and aortic valve were augmented compared to controls. The expression of miR-29b, p-Smad3, and Wnt3 and ß-catenin was significantly up-regulated, whereas TGF-ß3 was markedly down-regulated. However, compared with the CAVD model group, the calcium content and ALP activity in rats treated with antagomiR-29b were significantly decreased, and antagomiR-29b administration reversed the effects of CAVD model on the expression of miR-29b and osteogenic markers. Inhibition of miR-29b in CAVD rats prevented from vascular and valvular calcification and induced TGF-ß3 expression, suggesting that the miR-29b/TGF-ß3 axis may play a regulatory role in the pathogenesis of vascular and valvular calcification and could play a significant role in the treatment of CAVD and other cardiovascular diseases.

17.
Bioengineered ; 11(1): 824-828, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32772769

RESUMO

CAR-T cells therapy can give rise to most common and concerning two side effects - cytokine release syndrome (CRS) and neurotoxicity. But in our CD19 CAR-T cells therapy clinical trial, we observed 1 out of 17 patients with B-cell acute lymphoblastic leukemia (B-ALL) developed acute myelofibrosis(AMF) after grade IV CRS post to the CD19 CAR-T cells therapy. This finding suggests that the CAR-T cells therapy may have rare and serious AMF, which we should pay important attention to. Trial registration:NCT02968472. Registered 18 November 2016 - Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT02968472.

18.
Acta Pharmacol Sin ; 2020 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-32747720

RESUMO

Dry eye disease (DED) is a multifactorial disorder of the tears and ocular surface characterized by manifestations of dryness and irritation. Although the pathogenesis is not fully illuminated, it is recognized that inflammation has a prominent role in the development and deterioration of DED. ß-aminoarteether maleate (SM934) is a water-soluble artemisinin derivative with anti-inflammatory and immunosuppressive activities. In this study, we established scopolamine hydrobromide (SCOP)-induced rodent model as well as benzalkonium chloride (BAC)-induced rat model to investigate the therapeutic potential of SM934 for DED. We showed that topical application of SM934 (0.1%, 0.5%) significantly increased tear secretion, maintained the number of conjunctival goblet cells, reduced corneal damage, and decreased the levels of inflammatory mediators (TNF-α, IL-6, IL-10, or IL-1ß) in conjunctiva in SCOP-induced and BAC-induced DED models. Moreover, SM934 treatment reduced the accumulation of TLR4-expressing macrophages in conjunctiva, and suppressed the expression of inflammasome components, i.e., myeloid differentiation factor88 (MyD88), Nod-like receptor protein 3 (NLRP3), apoptosis-associated speck-like protein containing CARD (ASC), and cleaved caspase 1. In LPS-treated RAW 264.7 cells, we demonstrated that pretreatment with SM934 (10 µM) impeded the upregulation of TLR4 and downstream NF-κB/NLRP3 signaling proteins. Collectively, artemisinin analog SM934 exerts therapeutic benefits on DED by simultaneously reserving the structural integrity of ocular surface and preventing the corneal and conjunctival inflammation, suggested a further application of SM934 in ophthalmic therapy, especially for DED.

19.
Support Care Cancer ; 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32803728

RESUMO

BACKGROUND: The undertreatment of cancer pain is a global issue although many international guidelines and various studies bloom to explore the approaches in pain management. However, there is no standard care for cancer pain in routine practices. To set up a standardized procedure for improving cancer pain management in Taiwan, the Good Pain Management (GPM) program is explored to provide treatments following the US National Cancer Care Network (NCCN) Adult Cancer Pain Guideline. METHOD: Patients diagnosed with moderate-to-severe cancer pain were eligible and randomized into the GPM or control arm and observed the first 48 h to evaluate the effects of pain management between 2 arms. Pain control, adequacy of treatments, patient satisfaction, and quality of life (QoL) of eligible patients were analyzed. Ad hoc analyses based on the pain medication category were also conducted. RESULT: Fifty-one patients were enrolled, with 26 and 25 assigned to the GPM and control arms, respectively. Significant differences among the GPM and control arms were found including a greater decrease in the mean numerical rating scale (NRS) score in the GPM arm (- 4.6 vs. - 2.8), a lower proportion of moderate-to-severe pain in the GPM arm (23.2% vs. 39.8%), and a higher pain management index (PMI) score in the GPM arm (0.64 points vs. 0.33 points) (all p < 0.05). Ad hoc analyses revealed that the patient subgroups using strong opioids showed better patient satisfaction in GPM arm when compared with the same subgroup in the control arm. CONCLUSION: In summary, our study demonstrated that the implementation of a standardized pain assessment and management approach (GPM ward program) showed significant improvements on pain relief, decreased the portion of moderate-to-severe cancer pain, and increased patient satisfaction in the 1st 48 h after admission. The implementation of the GPM approach in the cancer ward may provide sooner and better improvement of cancer pain management for patients who suffered moderate-to-severe cancer pain. TRIAL REGISTRATION: ClinicalTrials.gov (Identifier: NCT03155516).

20.
Phys Rev E ; 102(1-1): 013304, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32794944

RESUMO

A quantified model-competition (QMC) mechanism for multiscale flows is extracted from the integral (analytical) solution of the Boltzmann-BGK model equation. In the QMC mechanism, the weight of the rarefied model and the weight of the continuum (aerodynamic and hydrodynamic) model are quantified. Then, a simplified unified wave-particle method (SUWP) is constructed based on the QMC mechanism. In the SUWP, the stochastic particle method and the continuum Navier-Stokes method are combined together. Their weights are determined by the QMC mechanism quantitatively in every discrete cell of the computational domain. The validity and accuracy of the present numerical method are examined using a series of test cases including the high nonequilibrium shock wave structure case, the unsteady Sod shock-tube case with a wide range of Kn number, the hypersonic flow around the circular cylinder from the free-molecular regime to the near continuum regime, and the viscous boundary layer case. In the construction process of the present method, an antidissipation effect in the continuum mechanism is also discussed.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA