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1.
Dalton Trans ; 2020 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-32068227

RESUMO

The reaction mechanism of bimetallic Pd-Zn-catalyzed cycloaddition of alkynyl aryl ethers with internal alkynes has been studied theoretically. Besides cycloaddition reaction, the dimerization of alkynyl aryl ethers was also considered. Both C6H5OC[triple bond, length as m-dash]CSiiPr3 and C6H5OC[triple bond, length as m-dash]CSiMe3 were chosen as the substrates. The reactions involve C-H activation of the substrate, acetic acid rotation, H transformation, MeC[triple bond, length as m-dash]CMe or substrate insertion into the Pd-phenyl bond and reductive elimination steps. It is found that cycloaddition is favored for C6H5OC[triple bond, length as m-dash]CSiiPr3, while dimerization is preferred for C6H5OC[triple bond, length as m-dash]CSiMe3, because the steric repulsion between two bulky SiiPr3 groups is relatively large and the steric repulsion between two small SiMe3 groups is relatively small. In addition, besides C6H5OC[triple bond, length as m-dash]CSiiPr3, four other substrates C6H5CH2C[triple bond, length as m-dash]CSiiPr3, C6H5C(O)C[triple bond, length as m-dash]CSiiPr3, C6H5SC[triple bond, length as m-dash]CSiiPr3 and C6H5N(H)C[triple bond, length as m-dash]CSiiPr3 have been calculated as the substrates for cycloaddition reaction with MeC[triple bond, length as m-dash]CMe. Among the five substrates, C6H5OC[triple bond, length as m-dash]CSiiPr3 has the lowest energy barrier (29.9 kcal mol-1), consistent with the experimental observation that C6H5OC[triple bond, length as m-dash]CSiiPr3 is the appropriate substrate for successful cycloaddition.

2.
J Am Chem Soc ; 2020 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-32070096

RESUMO

Charge transfer and recombination across the inorganic/organic interface in nanocrystal or quantum dot (QD)-molecule hybrid materials has been extensively studied. Principles of controlling charge transfer and recombination via energetics and electronic coupling have been established. However, the use of electron spin to control transfer and recombination pathways in such systems remains relatively underexplored. Here we use CdS QD-alizarin (AZ) as a model system to demonstrate this principle. Using time-resolved spectroscopy, we found that the charge separated states (QD--AZ+) created by selectively exciting AZ molecules mostly recombined to regenerate ground state complexes, whereas the apparently "same" charge separated states created by exciting QDs recombined to produce AZ molecular triplet states. Such a difference can be traced to the distinct spin configurations between excited QDs (QD*, with an ill-defined spin) and AZ (1AZ*, spin singlet) and the asymmetric electron and hole spin-flip rates in II-VI group QDs. The transferability of such a principle was confirmed by similar observations obtained for CdS QD-tetracene complexes. Opening an avenue of controlling charge transfer and recombination pathways via electron spin is potentially important for applications such as artificial photosynthesis.

3.
BMC Bioinformatics ; 21(1): 60, 2020 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-32070279

RESUMO

BACKGROUND: The interactions between non-coding RNAs (ncRNA) and proteins play an essential role in many biological processes. Several high-throughput experimental methods have been applied to detect ncRNA-protein interactions. However, these methods are time-consuming and expensive. Accurate and efficient computational methods can assist and accelerate the study of ncRNA-protein interactions. RESULTS: In this work, we develop a stacking ensemble computational framework, RPI-SE, for effectively predicting ncRNA-protein interactions. More specifically, to fully exploit protein and RNA sequence feature, Position Weight Matrix combined with Legendre Moments is applied to obtain protein evolutionary information. Meanwhile, k-mer sparse matrix is employed to extract efficient feature of ncRNA sequences. Finally, an ensemble learning framework integrated different types of base classifier is developed to predict ncRNA-protein interactions using these discriminative features. The accuracy and robustness of RPI-SE was evaluated on three benchmark data sets under five-fold cross-validation and compared with other state-of-the-art methods. CONCLUSIONS: The results demonstrate that RPI-SE is competent for ncRNA-protein interactions prediction task with high accuracy and robustness. It's anticipated that this work can provide a computational prediction tool to advance ncRNA-protein interactions related biomedical research.

4.
Environ Pollut ; 259: 113901, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-32023788

RESUMO

Soil antibiotic resistome and the nitrogen cycle are affected by florfenicol addition to manured soils but their interactions have not been fully described. In the present study, antibiotic resistance genes (ARGs) and nitrogen cycle genes possessed by soil bacteria were characterized using real-time fluorescence quantification PCR (qPCR) and metagenomic sequencing in a short-term (30 d) soil model experiment. Florfenicol significantly changed in the abundance of genes conferring resistance to aminoglycosides, ß-lactams, tetracyclines and macrolides. And the abundance of Sphingomonadaceae, the protein metabolic and nitrogen metabolic functions, as well as NO reductase, nitrate reductase, nitrite reductase and N2O reductase can also be affected by florfenicol. In this way, ARG types of genes conferring resistance to aminoglycosides, ß-lactamases, tetracyclines, colistin, fosfomycin, phenicols and trimethoprim were closely associated with multiple nitrogen cycle genes. Actinobacteria, Chlorobi, Firmicutes, Gemmatimonadetes, Nitrospirae, Proteobacteria and Verrucomicrobia played an important role in spreading of ARGs. Moreover, soil physicochemical properties were important factors affecting the distribution of soil flora. This study provides a theoretical basis for further exploration of the transmission regularity and interference mechanism of ARGs in soil bacteria responsible for nitrogen cycle.

5.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 28(1): 7-11, 2020 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-32027245

RESUMO

OBJECTIVE: To investigate the incidence, clinical features of U2AF1 gene mutation in patients with acute myeloid leukemia(AML) and its effect of prognosis. METHODS: A total of 161 patients with AML were enrolled. The second-generation sequencing method was used to detect U2AF1 gene mutation, and the relationship between U2AF1 mutation and clinical features, prognosis was analyzed. RESULTS: The mutation rate of U2AF1 gene in 161 AML patients was 3.73%. The counts of peripheral blood leukocytes and platelets in the U2AF1 gene mutation group were lower than those in the wild type group. The complete response rate of U2AF1 gene mutation group was 66.67%, while that in wild type group was 55.48%, which shows no significant difference between the two groups (P=0.70). The median EFS of wild type group and the mutant group was not reached and reached to 133 days, respectively (P=0.03), while the medium OS in two groups was not reached and reached to 210 days (P=0.01). CONCLUSION: The AML patients with U2AF1 mutation positive have a poor prognosis as compared with the wild type group, which may be a poor prognostic factor for acute myeloid leukemia.


Assuntos
Leucemia Mieloide Aguda , Fator de Processamento U2AF/genética , Humanos , Leucemia Mieloide Aguda/genética , Mutação , Prognóstico , Indução de Remissão
6.
Virus Res ; : 197886, 2020 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-32014528

RESUMO

Human adenovirus (HAdV) is an important respiratory pathogen in children that often leads to wider outbreaks of acute respiratory tract infection. HAdV group B contains the most important serotypes, HAdV-3 and HAdV-7, responsible for infection of humans. However, due to the species barrier, there is no suitable and effective animal model of HAdV-B for drug and vaccine development. Here we generated a recombinant capsid-chimeric HAdV-3, rAd3E-Fk5, by replacing the HAdV-3 fiber gene with that of the group C, type 5 virus. The rAd3E-Fk5 virus infected and replicated efficiently in both BALB/c mice and golden hamster primary kidney epithelial cells. However, the infectivity of the parent HAdV-3 virus was very low in hamster primary kidney cells. The infectivity of the recombinant rAd3E-Fk5 virus was also confirmed by staining for viral late protein, hexon, in infected primary rodent cells. These results indicate that the fiber protein may be a limiting factor in determining the species specificity of HAdV-3. This chimeric virus may be useful for developing an animal model of HAdV-3 infection, for vaccine and antiviral drug evaluation and for determination of the pathogenic mechanisms of HAdV-B.

7.
Dig Dis Sci ; 2020 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-32002758

RESUMO

Diet is a key regulator of microbiome structure and function across the lifespan. Microbial colonization in the first year of life has been actively researched; however, studies during childhood are sparse. Herein, the impact of dietary intake and pre- and probiotic interventions on microbiome composition of healthy infants and children from birth to adolescence is discussed. The microbiome of breastfed infants has lower microbial diversity and richness, higher Proteobacteria, and lower Bacteroidetes and Firmicutes than those formula-fed. As children consume more complex diets, associations between dietary patterns and the microbiota emerge. Like adults, the microbiota of children consuming a Western-style diet is associated with greater Bacteroidaceae and Ruminococcaceae and lower Prevotellaceae. Dietary fibers and pre- or/and probiotics have been tested to modulate the gut microbiota in early life. Human milk oligosaccharides and prebiotics added to infant formula are bifidogenic and decrease pathogens. In children, prebiotics, such as inulin, increase Bifidobacterium abundance and dietary fibers reduce fecal pH and increase alpha diversity and calcium absorption. Probiotics have been administered to the mother during pregnancy and breastfeeding or directly to the infant/child. Findings on maternal probiotic administration on bacterial taxa are inconsistent. When given directly to the infant/child, some changes in individual taxa are observed, but rarely is overall alpha or beta diversity affected. Cesarean-delivered infants appear to benefit to a greater degree than those born vaginally. Infancy and childhood represent an opportunity to beneficially manipulate the microbiome through dietary or prebiotic interventions, which has the potential to affect both short- and long-term health outcomes.

8.
Medicine (Baltimore) ; 99(7): e19122, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32049828

RESUMO

Our objective in this study was to determine the survival rate of patients with invasive breast cancer and identify the prognostic factors related to all-cause mortality during a 10-year follow-up.Analysis was performed on the medical records of 2002 patients newly diagnosed with breast cancer at a medical center in southern Taiwan between 2006 and 2017. The Kaplan-Meier method and Cox regression analysis were used to estimate survival and the independence of prognostic factors associated with all-cause mortality.Among the 2002 patients, 257 expired during the 10-year follow-up period. The overall survival rates were as follows: 3 years (91.1%), 5 years (85.6%), and 10 years (77.9%). The median survival time was 120.41 months (95% confidence interval: 118.48-122.33 months). Older age, pathologic tumor status, regional lymph node metastasis, distant metastasis, grade/differentiation, treatment modalities, and hormone therapy were significantly related to all-cause mortality.This study identified several clinical factors related to all-cause mortality as well as its relationship to distant metastasis and poor differentiation. Early diagnosis and treatment aimed at preventing recurrence are the keys to survival.

9.
Artigo em Inglês | MEDLINE | ID: mdl-32040703

RESUMO

Oral anticoagulants (OACs) are high alert medications and require high-quality management to optimize health outcomes. The objective of this scoping review was to identify barriers and facilitators (B&Fs) associated with the quality of OAC management. We searched MEDLINE, EMBASE, and CINAHL databases until July 12, 2018, and cross-referenced the bibliographies of the retrieved studies. We included quantitative and qualitative studies that assessed B&Fs to OAC management. The study selection and data extraction processes were performed in duplicate. Analyses included measuring the prevalence of reported B&Fs from studies reporting quantitative data, identifying B&Fs in narrative analyses, and identifying their impact on important outcomes of OAC management. B&Fs were coded and aggregated to higher-level themes using a consensus approach. Factors were described as "key" if they were statistically associated with important outcomes in a randomized trial or observational study. We included 62 studies-three randomized clinical trials (RCTs), 46 observational studies (cross-sectional studies, cohort studies, and case-control studies), 11 qualitative studies, and two mixed-methods studies. Factors identified could be grouped into four themes-therapy-related, patient-related, healthcare provider-related, and health system-related. Key barriers to optimal OAC management were mostly patient-related, whereas interventions focused on education or implementing protocols were shown through RCTs to be effective at improving knowledge scores of OAC patients. While multiple barriers and some facilitators were identified in this review, none was proven to be associated with clinical outcomes. With this in mind, individual physicians may wish to address the key barriers in their practice as a quality improvement initiative but system-wide or policy changes should await high-quality evidence. Future trials should address these factors.Systematic review registration: PROSPERO CRD42017069043.

10.
Chin Med J (Engl) ; 2020 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-32044814

RESUMO

BACKGROUND: A novel coronavirus (2019-nCoV) causing an outbreak of pneumonia in Wuhan, Hubei province of China was isolated in January 2020. This study aims to investigate its epidemiologic history, and analyzed the clinical characteristics, treatment regimens, and prognosis of patients infected with 2019-nCoV during this outbreak. METHODS: Clinical data from 137 2019-nCoV-infected patients admitted to the respiratory departments of nine tertiary hospitals in Hubei province from December 30, 2019 to January 24, 2020 were collected, including general status, clinical manifestations, laboratory test results, imaging characteristics, and treatment regimens. RESULTS: None of the 137 patients (61 males, 76 females, aged 20-83 years, mean age 55 ±â€Š16 years) had a definite history of exposure to Huanan Seafood Wholesale Market. Major initial symptoms included fever (112/137, 81.8%), coughing (66/137, 48.2%), and muscle pain or fatigue (44/137, 32.1%), with other, less typical initial symptoms observed at low frequency, including heart palpitations, diarrhea, and headache. Nearly 80% of the patients had normal or decreased white blood cell counts, and 72.3% (99/137) had lymphocytopenia. Lung involvement was present in all cases, with most chest computed tomography scans showing lesions in multiple lung lobes, some of which were dense; ground-glass opacity co-existed with consolidation shadows or cord-like shadows. Given the lack of effective drugs, treatment focused on symptomatic and respiratory support. Immunoglobulin G was delivered to some critically ill patients according to their condition. Systemic corticosteroid treatment did not show significant benefits. Notably, early respiratory support facilitated disease recovery and improved prognosis. The risk of death was primarily associated with age, underlying chronic diseases, and median interval from the appearance of initial symptoms to dyspnea. CONCLUSIONS: The majority of patients with 2019-nCoV coronavirus pneumonia present with fever as the first symptom, and most of them still showed typical manifestations of viral pneumonia on chest imaging. Middle-aged and elderly patients with underlying comorbidities are susceptible to respiratory failure and may have a poorer prognosis.

11.
Microbiol Res ; 234: 126426, 2020 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-32062364

RESUMO

In fungi, L-rhamnose (Rha) is converted via four enzymatic steps into pyruvate and L-lactaldehyde, which enter central carbon metabolism. In Aspergillus niger, only the genes involved in the first three steps of the Rha catabolic pathway have been identified and characterized, and the inducer of the pathway regulator RhaR remained unknown. In this study, we identified the gene (lkaA) involved in the conversion of L-2-keto-3-deoxyrhamnonate (L-KDR) into pyruvate and L-lactaldehyde, which is the last step of the Rha pathway. Deletion of lkaA resulted in impaired growth on L-rhamnose, and potentially in accumulation of L-KDR. Contrary to ΔlraA, ΔlrlA and ΔlrdA, the expression of the Rha-responsive genes that are under control of RhaR, were at the same levels in ΔlkaA and the reference strain, indicating the role of L-KDR as the inducer of the Rha pathway regulator.

12.
Nat Plants ; 6(2): 107-118, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32042158

RESUMO

Hornworts, liverworts and mosses are three early diverging clades of land plants, and together comprise the bryophytes. Here, we report the draft genome sequence of the hornwort Anthoceros angustus. Phylogenomic inferences confirm the monophyly of bryophytes, with hornworts sister to liverworts and mosses. The simple morphology of hornworts correlates with low genetic redundancy in plant body plan, while the basic transcriptional regulation toolkit for plant development has already been established in this early land plant lineage. Although the Anthoceros genome is small and characterized by minimal redundancy, expansions are observed in gene families related to RNA editing, UV protection and desiccation tolerance. The genome of A. angustus bears the signatures of horizontally transferred genes from bacteria and fungi, in particular of genes operating in stress-response and metabolic pathways. Our study provides insight into the unique features of hornworts and their molecular adaptations to live on land.

13.
Oral Dis ; 2020 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-31901146

RESUMO

OBJECTIVE: The temporomandibular joint (TMJ) displays a high remodelling capability in response to occlusion changes. The purpose of the current study was to investigate the responses of TMJ condyles of growing mice to the installation of a unilateral anterior crossbite (UAC) prosthesis and the replacement of the UAC prothesis with a bilateral anterior elevation (BAE) prosthesis. MATERIALS AND METHODS: C57BL/6J mice were randomly assigned to the blank control and experimental groups. In mice in the experimental groups, UAC was created, while in others, BAE was created after the creation of UAC or removal of UAC. Changes in TMJ condylar cartilage and subchondral bone were assessed. RESULTS: The degradation of condylar cartilage induced by UAC was reversed by BAE, as evaluated by cartilage histochemical changes, collagen II-positive area, collagen X-positive chondrocytes and expression levels of Adamts-5, Mmp13, Tnf-α and Il-1ß. Subchondral bone was assessed based on the subchondral bone volume, the number of TRAP-positive cells and the Opg/Rankl ratio. CONCLUSION: The growing mouse TMJ condyle displays a high remodelling capability, which can be degenerative or rehabilitative in response to the creation of UAC and the replacement of UAC with BAE. Early correction of occlusion is beneficial for the recovery of degenerative condyles.

14.
Pestic Biochem Physiol ; 163: 227-234, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31973861

RESUMO

Odorant-degrading enzymes (ODEs) are considered to play key roles in odorant inactivation to maintain the odorant receptor sensitivity of insects. Some members of carboxylesterase (CXE) is a major sub-family of ODEs. However, only a few CXEs have been functionally characterized so far. In the present study, we cloned the antennal esterase SexiCXE11 cDNA full-length sequences from the male antennae of a notorious crop pest, Spodoptera exigua, and its encoded 538 amino acids. It was similar to other insect esterases and had the characteristics of a carboxylesterase. We expressed recombinant enzyme in High-Five insect cells and obtained the high level purified recombinant protein by affinity column. Furthermore we test enzyme activity toward its two acetate sex pheromone components (Z9,E12-Tetradecadienyl acetate, Z9E12-14:Ac and Z9-Tetradecenyl acetate, Z9-14:Ac) and other 18 ester plant volatiles. Our results demonstrated that SexiCXE11 degraded acetate sex pheromone components with similar degradation activities (about 15.75% with Z9E12-14:Ac and 19.28% with Z9-14:Ac) and plant volatiles with a relatively high activity such as pentyl acetate and (Z)-3-hexenyl caproate. SexiCXE11 had high hydrolytic activity with these two ester odorants (>50% degradation), which is characterized that although a ubiquitous expression esterase SexiCXE11 may be partly involved with olfaction. This study may facilitate a better understanding of moth ODE differentiation and suggest strategies for the development of new pest behavior inhibitors.

16.
Gene ; 733: 144363, 2020 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-31935510

RESUMO

CRF system is comprised of 4 homologous lineages, 2 main receptors (CRF-R1 and CRF-R2), and a binding protein CRF-BP. The homologous lineages are corticotropin-releasing factor (CRF), urotensin I (UI)/sauvagine (SVG)/urocortin 1 (UCN1), urocortin 2 (UCN2), and urocortin 3 (UCN3), and UI, SVG, UCN1 are orthologous genes. CRF system genes are widely distributed in the brain and gastrointestinal tract, which may relate to feeding regulation. According the research progress about CRF system on mammals and non-mammals, this paper summarized the discovery, structure, tissue distribution, appetite regulation and mechanism of CRF system in animals, which can provide the reference for further research and production of feeding regulation and growth in mammals and fish species.

17.
Zhongguo Zhen Jiu ; 40(1): 8-12, 2020 Jan 12.
Artigo em Chinês | MEDLINE | ID: mdl-31930891

RESUMO

OBJECTIVE: To evaluate the clinical efficacy and partial action mechanism of mild moxibustion combined with salt-separated moxibustion for gastrointestinal discomfort caused by chemotherapy for breast cancer. METHODS: A total of 48 patients were randomly divided into an observation group and a control group, 24 cases in each group. The patients in the control group were treated with intravenous infusion of tropisetron hydrochloride (5 mg), once a day for three days; the patients in the observation group were additionally treated with mild moxibustion at Zusanli (ST 36), Zhongwan (CV 12), Guanyuan (CV 4), Qihai (CV 6) and salt-separated moxibustion at Shenque (CV 8), 15 min per treatment, once a day for 7 days. Before treatment and on the 7th day of chemotherapy, the levels of pepsinogenⅠ(PGⅠ), pepsinogenⅡ (PGⅡ), the ratio of PGⅠto PGⅡ (PGR) and gastrin 17 (G-17) in serum were measured. Before treatment and on the 3rd, 5th, 7th day of chemotherapy, the gastrointestinal reactions (nausea, vomiting, constipation, diarrhea) were compared between the two groups. RESULTS: On the 7th day of chemotherapy, the serum levels of PGⅠ, PGⅡand G-17 in the observation group were lower than those in the control group (P<0.05), and the difference in the level of PGR in serum between the observation group and the control group was not statistically significant (P>0.05). The total scores of nausea, vomiting and constipation during chemotherapy in the observation group were significantly lower than those in the control group (all P<0.05). CONCLUSION: The mild moxibustion combined with salt-separated moxibustion could effectively improve the symptoms of nausea, vomiting and constipation caused by chemotherapy in patients with breast cancer, and its mechanism may be related to the down-regulation of the levels of PGⅠ, PGⅡ and G-17 in serum.


Assuntos
Neoplasias da Mama , Moxibustão , Pontos de Acupuntura , Neoplasias da Mama/terapia , Humanos , Náusea , Resultado do Tratamento
18.
Nat Prod Res ; : 1-9, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31997645

RESUMO

In an attempt to synthesize carvotacetone analogues, new 3-O-benzyl-carvotacetone (10) and previously reported 3-hydroxy-2-isopropyl-5-methyl-p-benzoquinone (11) were synthesized from piperitone (7). In this work, we describe the synthesis of 10 and other analogues from 7. Luche reduction of 7 to cis-piperitol (8), followed by benzylation yielded 3-O-benzyl-piperitol (9). Riley oxidation of 9 afforded corresponding ketone 10, 11 and 3-benzyloxy-4-isopropylcyclohex-1-enecarbaldehyde (12). Structures of these compounds were determined based on NMR, IR and LC-MS spectral data. Compound 11, exhibited antiplasmodial activities against chloroquine-sensitive (D6) and resistant (W2) strains of Plasmodium falciparum with IC50 values of 0.697 and 0.653 µg/mL, respectively. In addition, compound 11 was active against Cryptococcus neoformans with an IC50 value of 3.11 µg/mL, compared to reference standard fluconazole (IC50 value of 1.87 µg/mL), while 10 and 12 were inactive against both organisms. This is the first report of the antiplasmodial and anticryptococcal activity of compound 11.

19.
Int J Oncol ; 56(2): 470-479, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31894264

RESUMO

microRNAs (miRNAs or miRs) are endogenous noncoding single­stranded RNA molecules that can regulate gene expression by targeting the 3'­untranslated region and play an important role in many biological and pathological processes, such as inflammation and cancer. In this study, we found that miR­20b was significantly increased in human non­small cell lung cancer (NSCLC) cell lines and patient tissues, suggesting that it may possess a carcinogenic role in lung cancer. This miRNA promoted the proliferation, migration and invasion of NSCLC cells by targeting and downregulating the expression of adenomatous polyposis coli (APC), which is a negative regulator of the canonical Wnt signaling pathway. Wnt signaling activation may increase transcription of miR­20b. Therefore, miR­20b and canonical Wnt signaling were coupled through a feed­forward positive feedback loop, forming a biological regulatory circuit. Finally, an in vivo investigation further demonstrated that an increase in miR­20b promoted the growth of cancer cells. Overall, our findings offer evidence that miR­20b may contribute to the development of NSCLC by inhibiting APC via the canonical Wnt signaling pathway.

20.
ACS Appl Mater Interfaces ; 12(5): 5838-5846, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31922710

RESUMO

The thermoelectric materials with high values of the dimensionless figure of merit (ZT) are among the most important new energy resources. Too much attention has been paid to the search of high-ZT thermoelectric materials, and the one with ZT = 5 has been reported recently. Here, a remarkably high ZT = 7.38 is predicted for the n-type half-Heusler compound of BCaGa at 700 K. To understand the high-ZT behavior, we studied electronic properties of BXGa (X = Be, Mg, and Ca) with first-principles calculations based on the density functional theory. The stabilities of the structures of BXGa (X = Be, Mg, and Ca) are confirmed by phonon dispersion. The transport properties are determined by the semiclassical Boltzmann transport theory. We evaluate the relaxation time by using the deformation potential theory and the lattice thermal conductivity based on the elastic coefficients. The results demonstrate that such a high efficiency of BCaGa arises from the intrinsic coordination of the ultralow lattice and electronic thermal conductivity and the larger power factor at certain carrier concentration and temperature. The high n-type power factor originates from the large relaxation time, which results in a light, twofold degenerate conduction-band pocket at the Γ point. In contrast, the power factors of BBeGa and BMgGa are smaller because of their flat-and-dispersive valence band. It is expected that the remarkable results for BXGa could encourage more experimental and theoretical investigations to develop efficient thermoelectric materials with BXGa.

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