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Constructed wetland systems have been widely used in China due to their advantages of good treatment effect, low cost and environmental friendliness. However, traditional constructed wetlands have challenges in application such as deactivation due to filler clogging, difficulty in filler replacement and low adaptability. To address the above problems, this research proposes a modular filler design constructed wetland based on the concept of assembly construction, which can quickly replace the clogged filler without destroying the overall structure of the wetland. Four commonly used fillers were selected and applied to the pilot system of the assembled constructed wetland in this study, in order to investigate the purification effect of the constructed wetland system with different filler module combinations (CW1, CW2, CW3) on the simulated wastewater. The results showed that the filler combination CW1 was the best for the removal of NH4+-N, and for TP and COD, CW2 has the best removal effect. Therefore, the assembled constructed wetland is adjustable and substantially reduces the maintenance cost, which provides technical guidance for its application in engineering.
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Poluentes Químicos da Água , Áreas Alagadas , Purificação da Água/métodos , Eliminação de Resíduos Líquidos/métodos , Análise da Demanda Biológica de Oxigênio , Nitrogênio/química , Fósforo/químicaRESUMO
The surface glycoprotein (S protein) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was used to develop coronavirus disease 2019 (COVID-19) vaccines. However, SARS-CoV-2, especially the S protein, has undergone rapid evolution and mutation, which has remained to be determined. Here, we analyzed and compared the early (12 237) and the current (more than 10 million) SARS-CoV-2 strains to identify the mutation features and geographical distribution of the S gene and S protein. Results showed that in the early strains, most of the loci were with relative low mutation frequency except S: 23403 (4486 strains), while in the current strains, there was a surge in the mutation strains and frequency, with S: 23403 constantly being the highest one, but tremendously increased to approximately 1050 times. Furthermore, D614 (S: 23403) was one of the most highly frequent mutations in the S protein of Omicron as of March 2022, and most of the mutant strains were still from the United States, and the United Kingdom. Further analysis demonstrated that in the receptor-binding domain, most of the loci with low mutation frequency in the early strains, while S: 22995 was nowadays the most prevalent loci with 3 122 491 strains in the current strains. Overall, we compare the mutation features of the S region in SARS-CoV-2 strains between the early and the current stains, providing insight into further studies in concert with emerging SARS-CoV-2 variants for COVID-19 vaccines.
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COVID-19 , SARS-CoV-2 , COVID-19/epidemiologia , Vacinas contra COVID-19 , Humanos , Glicoproteínas de Membrana/genética , Mutação , SARS-CoV-2/genética , Glicoproteína da Espícula de CoronavírusRESUMO
PURPOSE: To evaluate optimal warming time, the early warming or the routine warming time, for transferring vitrified-warmed and cultured overnight cleavage stage of the slow-growing embryos on day 3 in frozen embryo transfer (FET) cycle. METHODS: This was a retrospective cohort study from January 2017 to July 2018. A total of 705 FET patients aged < 40 years were included and 1486 embryos were formed, of which 1366 embryos were eventually transferred. RESULTS: For slow-growing embryos, the clinical pregnancy rate of early warming group [152/468 (32.5%)] was significantly higher than that of routine warming group (55/235 (23.4%)) [OR 1.39 (CI 1.06-1.81), p = 0.01], while there was no statistically significant difference in pregnancy loss in early warming group [39/170 (22.9%)] versus in routine warming group [16/62 (25.8%)] [OR 0.89 (CI 0.53-1.47), p = 0.65]. CONCLUSION: For slow-growing embryos, higher pregnancy outcomes were shown in early warming strategy as compared to the routine warming, which suggested that the improvement of endometrium-embryo synchronism may correct the time difference brought by the slow-growing embryos.
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Criopreservação , Vitrificação , Adulto , Estudos de Coortes , Transferência Embrionária , Feminino , Humanos , Gravidez , Taxa de Gravidez , Estudos RetrospectivosRESUMO
It had been suggested, after facilitating the hatching process, improved pregnancy outcomes could be attained in embryos with thick and hard zona. This study aimed to determine the effect of zona thinning on pregnancy outcomes in poor-quality frozen-thawed blastocysts. This retrospective study included 230 women (≤ 40 years) who underwent frozen embryo transfer of poor-quality blastocysts (scored < 3BB). In total, 105 patients were in the assisted hatching group in which the zona was thinned by laser before transfer and 125 patients were in the control group in which the blastocysts were non-manipulated. Patients' demographics, cycle characteristics, and pregnancy outcomes were compared between the assisted hatching group and the control group. Further, regression analysis was applied to test the correlation between assisted hatching and live birth. All parameters in the patients' demographic characteristics and the cycle's characteristics were not significantly different between two groups. As for pregnancy outcomes, the second trimester pregnancy loss was significantly higher in the assisted hatching group (P = 0.035). Other pregnancy outcomes, including implantation rate, clinical pregnancy rate, biochemical miscarriage rate, the first trimester pregnancy loss, ongoing pregnancy rate, and live birth rate were comparable between two groups. The logistic regression analysis demonstrated no association between live birth and assisted hatching (univariate, OR = 0.787, P > 0.05; multivariate, OR = 0.652, P > 0.05), and the area under the receiver operating characteristic curve of the regression model was almost 0.7. It suggested that zona thinning may not be supposed to perform on poor-quality, frozen-thawed blastocysts. The indications of assisted hatching were still needed to further investigate.
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Criopreservação , Resultado da Gravidez , Blastocisto , Transferência Embrionária , Feminino , Humanos , Lasers , Gravidez , Estudos RetrospectivosRESUMO
A forward-backward labeled multi-Bernoulli (LMB) smoother is proposed for multi-target tracking. The proposed smoother consists of two components corresponding to forward LMB filtering and backward LMB smoothing, respectively. The former is the standard LMB filter and the latter is proved to be closed under LMB prior. It is also shown that the proposed LMB smoother can improve both the cardinality estimation and the state estimation, and the major computational complexity is linear with the number of targets. Implementation based on the Sequential Monte Carlo method in a representative scenario has demonstrated the effectiveness and computational efficiency of the proposed smoother in comparison to existing approaches.
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Images acquired by airborne infrared search and track (IRST) systems are often characterized by nonuniform noise. In this paper, a scene-based nonuniformity correction method for infrared focal-plane arrays (FPAs) is proposed based on the constant statistics of the received radiation ratios of adjacent pixels. The gain of each pixel is computed recursively based on the ratios between adjacent pixels, which are estimated through a median operation. Then, an elaborate mathematical model describing the error propagation, derived from random noise and the recursive calculation procedure, is established. The proposed method maintains the characteristics of traditional methods in calibrating the whole electro-optics chain, in compensating for temporal drifts, and in not preserving the radiometric accuracy of the system. Moreover, the proposed method is robust since the frame number is the only variant, and is suitable for real-time applications owing to its low computational complexity and simplicity of implementation. The experimental results, on different scenes from a proof-of-concept point target detection system with a long-wave Sofradir FPA, demonstrate the compelling performance of the proposed method.
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The research on optical imaging characteristics of infrared dim point targets in the presence of nonstationary cloud clutter and random noise is necessary for target detection. We analyze the energy concentration of point targets that are less than 3×3 pixels in size and deduce a simulation model of the point target imaging process. Then we adopt omnidirectional multiscale structural elements to detect all the possible targets distributing in every direction. The adaptive threshold and the energy concentration criterion are employed to eliminate false alarms. Finally, the trajectory of point targets is obtained after the low-order recursive correlation. The results show that the detection probability of the proposed method reaches 99.8% with 0.2% false alarm probability. It demonstrates that the proposed method has a good performance to suppress complex background and random noise. Also, it has the advantage of low complexity and easy implementation in a real-time system.
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Focal-plane arrays (FPAs) are often interfered by heavy fixed-pattern noise, which severely degrades the detection rate and increases the false alarms in airborne point target detection systems. Thus, high-precision nonuniformity correction is an essential preprocessing step. In this paper, a new nonuniformity correction method is proposed based on a staircase scene. This correction method can compensate for the nonlinear response of the detector and calibrate the entire optical system with computational efficiency and implementation simplicity. Then, a proof-of-concept point target detection system is established with a long-wave Sofradir FPA. Finally, the local standard deviation of the corrected image and the signal-to-clutter ratio of the Airy disk of a Boeing B738 are measured to evaluate the performance of the proposed nonuniformity correction method. Our experimental results demonstrate that the proposed correction method achieves high-quality corrections.
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Two new prenylated phloroglucinol derivatives (1-2), and a known compound furohyperforim isomer 2 (3), were isolated from the aerial parts of Hypericum scabrum. Their structures were elucidated by various spectroscopic methods, including MS, IR, UV, and NMR.
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Medicamentos de Ervas Chinesas/isolamento & purificação , Hypericum/química , Floroglucinol/isolamento & purificação , Medicamentos de Ervas Chinesas/química , Medicamentos de Ervas Chinesas/farmacologia , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Floroglucinol/química , Prenilação , EstereoisomerismoRESUMO
Two new polyprenylated acylphloroglucinols, (1S,32R,5S,6R,7R)-6-((R)-3,4-di-hydroxy-4-methylpentyl)-2-(2-hydroxypropan-2-yl)-7-isobutyryl-6-methyl-5,9-bis(3-methylbut-2-en-1-yl)-4,5,6,7-tetrahydro-2H-32,7-methanocycloocta[b]furan-8,10(3H)-dione (1) and (4R,5R,7R)-4-((R)-3,4-dihydroxy-4-methylpentyl)-2,2,4-trimethyl-5,7-bis(3-methyl-but-2-en-1-yl)-7-(5-methylhex-4-enoyl)-4,5,6,7-tetrahydrobenzofuran-3(2H)-one (2) were isolated from Hypericum scabrum. The structures were elucidated by means of spectroscopic methods, including MS, IR, NMR, OR, and CD.
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Medicamentos de Ervas Chinesas/isolamento & purificação , Hypericum/química , Floroglucinol/análogos & derivados , Medicamentos de Ervas Chinesas/química , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Floroglucinol/química , EstereoisomerismoRESUMO
BACKGROUND: The 2016 Patient-Oriented Strategy Encompassing IndividualizeD Oocyte Number (POSEIDON) criteria redefined the poor responders as low prognosis patients. The embryo transfer strategy for POSEIDON patients remained to be addressed. This study aimed to investigate the optimized number of embryos to transfer for unexpected low-prognosis patients (POSEIDON Group 1 and Group 2) with blastocyst transfer in their first frozen cycle. METHODS: A retrospective cohort study of 2970 patients who underwent frozen-thawed embryo transfer (FET) between January 2018 and December 2021. Patients from POSEIDON Group 1 (N = 219) and Group 2 (N = 135) who underwent blastocyst transfer in their first FET cycles were included and divided into the elective single embryo transfer (eSET) group and the double embryo transfer (DET) group. RESULTS: For POSEIDON Group 1, the live birth rate per embryo transfer of the DET group was slightly higher than the eSET group (52.17% vs 46.15%, OR 0.786, 95% CI 0.462-1.337, P = 0.374; adjusted OR (aOR) 0.622, 95% CI 0.340-1.140, P = 0.124), while a significant increase of 20.00% in the multiple birth rate was shown. For Group 2, higher live birth rates were observed in the DET group compared to the eSET group (38.46% vs 20.48%, OR 0.412, 95% CI 0.190-0.892, P = 0.024; aOR 0.358, 95% CI 0.155-0.828, P = 0.016). The difference in the multiple birth rate was 20.00% without statistical significance. Univariate and multivariate analyses revealed that age (OR 0.759, 95% CI .624-0.922, P = 0.006 and OR 0.751, 95% CI 0.605-0.932, P = 0.009) and the number of transferred embryos (OR 0.412, 95% CI 0.190-0.892, P = 0.024 and OR 0.367, 95% CI 0.161-0.840, P = 0.018) were significant variables for the live birth rate in POSEIDON Group 2. CONCLUSIONS: The findings in the present study showed that eSET was preferred in the first frozen cycle for POSEIDON Group 1 to avoid unnecessary risks. Double embryo transfer strategy could be considered to improve the success rate for POSEIDON Group 2 with caution. Further stratification by age is needed for a more scientific discussion about the embryo transfer strategy for POSEIDON patients.
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Transferência Embrionária , Humanos , Estudos Retrospectivos , Feminino , Transferência Embrionária/métodos , Adulto , Gravidez , Taxa de Gravidez , Fertilização in vitro/métodos , Coeficiente de NatalidadeRESUMO
Although m6A modifications are associated with tumor progression, and anti-tumor immune responses, the role of m6A regulators in HPV-related carcinogenesis has not been well resolved. To provide evidence for the role of m6A regulators in HPV-related carcinogenesis and identify potential therapeutic targets for HPV-related cancers, integrative analyses of m6A regulators in 1,485 head and neck squamous cell carcinoma (HNSC) patients and 507 cervical squamous cell carcinoma (CESC) patients was performed and identified that an m6A regulator, METTL3, was highly expressed in tumors and was related to the poor prognosis in HNSC and CESC. In HPV-positive tumors, METTL3 was positively associated with tumor HPV status, such as HPV integration status, E6 and unspliced-E6 expression, and p16 expression. Further analysis demonstrated that METTL3 high status was negatively correlated with tumor immune cell infiltrations and facilitated the expression of immunosuppressive immune checkpoint molecules (i.e., PD-L1). Cell-derived xenograft models demonstrated that METTL3 inhibitor combined with anti-PD1 therapy promoted immunotherapy of CESC in vivo. Overall, this study identified that METTL3 high status, is associated with poor prognosis and HPV status, and serves as a mediator of the immunosuppressive tumor microenvironment in HPV-associated cancer, which provides a promising therapeutic target for anti-cancer immunotherapy.
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Neoplasias de Cabeça e Pescoço , Metiltransferases , Infecções por Papillomavirus , Carcinogênese , Humanos , Metiltransferases/genética , Metiltransferases/metabolismo , Infecções por Papillomavirus/complicações , Carcinoma de Células Escamosas de Cabeça e Pescoço , Microambiente Tumoral/genéticaRESUMO
INTRODUCTION: We explored the association between clinical outcomes and the cleavage rate of day-3 cleavage slow-growing embryos after overnight culture. METHODS: The data collected from 303 frozen embryo transfer (FET) cycles with 606 4-cell or 5-cell embryos cultured overnight (18-22 h) after thawing were analyzed. Based on the growth rate after the overnight culture, the embryos were divided into three groups: no embryo reaching eight cells (Group I), either one of the two embryos reaching eight cells (Group II), and both two embryos reaching eight cells or more (Group III). A statistical analysis of the different clinical outcomes from the three groups was performed. RESULTS: Biochemical pregnancy rate (OR 3.22; p = 0.001), implantation rate (OR 2.44; p = 0.002), clinical pregnancy rate (OR 3.04; p = 0.001), ongoing pregnancy rate (OR 3.14; p = 0.001), and live birth rate (OR 2.78; p = 0.004) were significantly higher in Group III as compared to Group I. Group II had a significantly higher biochemical pregnancy rate (OR 2.02; p = 0.013) and implantation rate (OR 1.77; p = 0.019) than Group I. CONCLUSIONS: The capability of day-3 cleavage slow-growing embryos to reach eight cells, especially that of two embryos reaching eight cells by overnight culture, appear to result in a better pregnancy outcome.
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BACKGROUND: Ileostomy was widely used during colorectal cancer (CRC) surgery and peristomal dermatitis was one of the most common stoma-relative complications. Stoma education class may reduce the rate of peristomal dermatitis. METHODS: We enrolled patients who were diagnosed with rectal cancer and underwent surgery with ileostomy between January 2018 to December 2018 at a single tertiary hospital. The general demographic information of patients along with the participation in stoma education class and the occurrence of peristomal dermatitis were analyzed. RESULTS: A total of 491 patients were included in the study, and 162 patients (32.99%) participated in the stoma education class. Eighty-five patients (17.31%) suffered peristomal dermatitis within one month after ileostomy. The rate of peristomal dermatitis in the stoma education group was significantly lower than that in the control group (11.11% vs. 20.36%, P=0.011). Regardless of the education level, the risk of peristomal dermatitis in the education group was reduced (P<0.05). Lower peristomal dermatitis rates were found in patients who were younger than 60 years (P=0.012), whose stoma were taken care of by other people (P=0.014), or without diabetes (P=0.026). Univariate and Multivariate analysis showed that stoma education was the only factor associated with the decrease in rates of peristomal dermatitis (OR =0.458, P=0.008), while diabetes was an independent risk factor (OR =3.732, P<0.001). CONCLUSIONS: Postoperative stoma education class significantly decreased the rate of peristomal dermatitis in the early postoperative period in CRC patients with ileostomy, especially for those who were younger than 60 years, received stoma care from others or without diabetes.
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Background: rs13405728 was identified as one of the most prevalent susceptibility loci for polycystic ovary syndrome (PCOS) in Han Chinese and Caucasian women. However, the target genes and potential mechanisms of the rs13405728 locus remain to be determined. Methods: Three-dimensional (3D) genome interactions from the ovary tissue were characterized via high-through chromosome conformation capture (Hi-C) and Capture Hi-C technologies to identify putative targets at the rs13405728 locus. Combined analyses of eQTL, RNA-Seq, DNase-Seq, ChIP-Seq, and sing-cell sequencing were performed to explore the molecular roles of these target genes in PCOS. PCOS-like mice were applied to verify the expression patterns. Results: Generally, STON1 and FSHR were identified as potential targets of the rs13405728 locus in 3D genomic interactions with epigenomic regulatory peaks, with STON1 (P=0.0423) and FSHR (P=0.0013) being highly expressed in PCOS patients. STON1 co-expressed genes were associated with metabolic processes (P=0.0008) in adipocytes (P=0.0001), which was validated in the fat tissue (P<0.0001) and ovary (P=0.0035) from fat-diet mice. The immune system process (GO:0002376) was enriched in FSHR co-expressed genes (P=0.0002) and PCOS patients (P=0.0002), with CD4 high expression in PCOS patients (P=0.0316) and PCOS-like models (P=0.0079). Meanwhile, FSHR expression was positively correlated with CD4 expression in PCOS patients (P=0.0252) and PCOS-like models (P=0.0178). Furthermore, androgen receptor (AR) was identified as the common transcription factor for STON1 and FSHR and positively correlated with the expression of STON1 (P=0.039) and FSHR (P=4e-06) in ovary tissues and PCOS-like mice. Conclusion: Overall, we identified STON1 and FSHR as potential targets for the rs13405728 locus and their roles in the processes of adipocyte metabolism and CD4 immune expression in PCOS, which provides 3D genomic insight into the pathogenesis of PCOS.
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Proteínas de Membrana/genética , Síndrome do Ovário Policístico/genética , Receptores do FSH/genética , Fatores Genéricos de Transcrição/genética , Adipócitos/metabolismo , Tecido Adiposo/metabolismo , Animais , Antígenos CD4/imunologia , Feminino , Expressão Gênica , Loci Gênicos , Genoma , Humanos , Proteínas de Membrana/metabolismo , Camundongos Endogâmicos C57BL , Ovário/metabolismo , Síndrome do Ovário Policístico/imunologia , Síndrome do Ovário Policístico/metabolismo , Receptores Androgênicos/genética , Receptores do FSH/imunologia , Fatores Genéricos de Transcrição/metabolismoRESUMO
OBJECTIVE: Individual differences in glycemic response to metformin in antidiabetic treatment exist widely. Although some associated genetic variations have been discovered, they still cannot accurately predict metformin response. In the current study, we set out to investigate novel genetic variants affecting metformin response in Chinese type 2 diabetes (T2D) patients. METHODS: A two-stage study enrolled 500 T2D patients who received metformin, glibenclamide or a combination of both were recruited from 2009 to 2012 in China. Change of HbA1c, adjusted by clinical covariates, was used to evaluate glycemic response to metformin. Selected single nucleotide polymorphisms (SNPs) were genotyped using the Infinium iSelect and/or Illumina GoldenGate genotyping platform. A linear regression model was used to evaluate the association between SNPs and response. RESULTS: A total of 3739 SNPs were screened in Stage 1, of which 50 were associated with drug response. Except for one genetic variant preferred to affect glibenclamide, the remaining SNPs were subsequently verified in Stage 2, and two SNPs were successfully validated. These were PRKAG2 rs2727528 (discovery group: ß=-0.212, P=0.046; validation group: ß=-0.269, P=0.028) and PRKAG2 rs1105842 (discovery group: ß=0.205, P=0.048; validation group: ß=0.273, P=0.025). C allele carriers of rs2727528 and C allele carriers of rs1105842 would have a larger difference of HbA1c level when using metformin. CONCLUSION: Two variants rs2727528 and rs1105842 in PRKAG2, encoding γ2 subunit of AMP-activated protein kinase (AMPK), were found to be associated with metformin response in Chinese T2D patients. These findings may provide some novel information for personalized pharmacotherapy of metformin in China.
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Human papillomavirus (HPV) infection and gene mutations were reputed as key factors in cervical carcinoma (CC) and head and neck squamous cell carcinoma (HNSCC). However, the associations of HPV status and gene mutations remain to be determined. This study aims to identify molecular patterns of LRP1B mutation and HPV status via rewiring tumor samples of HNSCC (n=1478) and CC (n=178) from the TCGA dataset. Here, we found that LRP1B mutation was associated with HPV status in CC (P=0.040) and HNSCC (P=0.044), especially in HPV 16 integrated CC (P=0.036). Cancer survival analysis demonstrated that samples with LRP1B mutation showed poor disease outcomes in CC (P=0.013) and HNSCC (P=0.0124). In addition, the expression status of LPR1B was more favorable for prediction than TP53 or RB1 in CC and HNSCC. Mutation clustering analysis showed that samples with LRP1B mutation showed higher mutation count in CC (P=1.76e-67) and HNSCC (P<10e-10). Further analysis identified 289 co-occurrence genes in these two cancer types, which were enriched in PI3K signaling, cell division process, and chromosome segregation process, et al. The 289-co-occurrence gene signature identified a cluster of patients with a higher portion of copy number variation (CNV) lost in the genome, different tumor HPV status (P<10e-10), higher mutation count (P<10e-10), higher fraction genome altered value (P=2.078e-4), higher aneuploidy score (P=3.362e-4), and earlier started the smoking year (P=2.572e-4), which were associated with shorter overall survival (P=0.0103) in CC and HNSCC samples. Overall, LRP1B mutation was associated with tumor HPV status and was an unfavorable prognostic biomarker for CC and HNSCC.
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Neoplasias de Cabeça e Pescoço/genética , Mutação , Papillomaviridae , Infecções por Papillomavirus/genética , Receptores de LDL/genética , Carcinoma de Células Escamosas de Cabeça e Pescoço/genética , Neoplasias do Colo do Útero/genética , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Variações do Número de Cópias de DNA , Análise Mutacional de DNA , DNA de Neoplasias/genética , DNA de Neoplasias/metabolismo , Feminino , Perfilação da Expressão Gênica , Neoplasias de Cabeça e Pescoço/metabolismo , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Pessoa de Meia-Idade , Infecções por Papillomavirus/metabolismo , Infecções por Papillomavirus/patologia , Receptores de LDL/metabolismo , Carcinoma de Células Escamosas de Cabeça e Pescoço/metabolismo , Carcinoma de Células Escamosas de Cabeça e Pescoço/patologia , Neoplasias do Colo do Útero/metabolismo , Neoplasias do Colo do Útero/patologiaRESUMO
The retinoic acid (RA) signaling pathway is crucial for many biological processes. The RA transporter, Cellular Retinoic-Acid Binding Protein 2 (CRABP2), is abnormally expressed in various tumor types. CRABP2 presents significant effects on tumorous behaviors and functions, including cell proliferation, apoptosis, invasion, migration, metastasis, and angiogenesis. The tumorigenesis mechanism of CRABP2, as both suppressor and promotor, is complicated, therefore, there remains the need for further investigation. Elucidating the regulating mechanisms in a specific stage of the tumor could facilitate CRABP2 to be a biomarker in cancer diagnosis and prognosis. Besides, clarifying the pathways of CRABP2 in cancer development will contribute to the gene-targeted therapy. In this review, we summarized the expression, distribution, and mechanism of CRABP2 in solid tumors. Illuminating the CRABP2 signaling pathway may benefit understanding the retinoid signaling pathway, providing a useful biomarker for future clinical trials.
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Regulação Neoplásica da Expressão Gênica , Neoplasias/genética , Neovascularização Patológica/genética , Receptores do Ácido Retinoico/genética , Tretinoína/metabolismo , Apoptose , Transporte Biológico , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Proteínas de Ligação a Ácido Graxo/genética , Proteínas de Ligação a Ácido Graxo/metabolismo , Humanos , Metástase Linfática , Estadiamento de Neoplasias , Neoplasias/irrigação sanguínea , Neoplasias/diagnóstico , Neoplasias/metabolismo , Neovascularização Patológica/diagnóstico , Neovascularização Patológica/metabolismo , Neovascularização Patológica/patologia , Receptores do Ácido Retinoico/metabolismo , Transdução de SinaisRESUMO
On the basis of the quantum Sutton-Chen potential, the rapid solidification processes of liquid silver have been studied by molecular dynamics simulation for four cooling rates. By means of several analysis methods, the competitions and transitions between microstructures during the cooling processes have been analyzed intensively. It is found that there are two phase transitions in all simulation processes. The first one is from liquid state to metastable (transitional) body-centered cubic (bcc) phase. The initial crystallization temperature T(ic) increases with the decrease of the cooling rate. The second one is from the transitional bcc phase to the final solid phase. This study validates the Ostwald's step rule and provides evidence for the prediction that the metastable bcc phase forms first from liquid. Further analyses reveal that the final solid at 273 K can be a mixture of hexagonal close-packed (hcp) and face-centered cubic (fcc) microstructures with various proportions of the two, and the slower the cooling rate is, the higher proportion the fcc structure occupies.
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To investigate the structural evolution and hereditary mechanism of icosahedral nano-clusters formed during rapid solidification, a molecular dynamics (MD) simulation study has been performed for a system consisting of 107 atoms of liquid Mg70Zn30 alloy. Adopting Honeycutt-Anderson (HA) bond-type index method and cluster type index method (CTIM-3) to analyse the microstructures in the system it is found that for all the nano-clusters including 2~8 icosahedral clusters in the system, there are 62 kinds of geometrical structures, and those can be classified, by the configurations of the central atoms of basic clusters they contained, into four types: chain-like, triangle-tailed, quadrilateral-tailed and pyramidal-tailed. The evolution of icosahedral nano-clusters can be conducted by perfect heredity and replacement heredity, and the perfect heredity emerges when temperature is slightly less than Tm then increase rapidly and far exceeds the replacement heredity at Tg; while for the replacement heredity, there are three major modes: replaced by triangle (3-atoms), quadrangle (4-atoms) and pentagonal pyramid (6-atoms), rather than by single atom step by step during rapid solidification processes.