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1.
Nature ; 565(7739): 331-336, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30559378

RESUMO

Discovered decades ago, the quantum Hall effect remains one of the most studied phenomena in condensed matter physics and is relevant for research areas such as topological phases, strong electron correlations and quantum computing1-5. The quantized electron transport that is characteristic of the quantum Hall effect typically originates from chiral edge states-ballistic conducting channels that emerge when two-dimensional electron systems are subjected to large magnetic fields2. However, whether the quantum Hall effect can be extended to higher dimensions without simply stacking two-dimensional systems is unknown. Here we report evidence of a new type of quantum Hall effect, based on Weyl orbits in nanostructures of the three-dimensional topological semimetal Cd3As2. The Weyl orbits consist of Fermi arcs (open arc-like surface states) on opposite surfaces of the sample connected by one-dimensional chiral Landau levels along the magnetic field through the bulk6,7. This transport through the bulk results in an additional contribution (compared to stacked two-dimensional systems and which depends on the sample thickness) to the quantum phase of the Weyl orbit. Consequently, chiral states can emerge even in the bulk. To measure these quantum phase shifts and search for the associated chiral modes in the bulk, we conduct transport experiments using wedge-shaped Cd3As2 nanostructures with variable thickness. We find that the quantum Hall transport is strongly modulated by the sample thickness. The dependence of the Landau levels on the magnitude and direction of the magnetic field and on the sample thickness agrees with theoretical predictions based on the modified Lifshitz-Onsager relation for the Weyl orbits. Nanostructures of topological semimetals thus provide a way of exploring quantum Hall physics in three-dimensional materials with enhanced tunability.

2.
BMC Gastroenterol ; 24(1): 76, 2024 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-38365575

RESUMO

PURPOSE: Cytokines regulate the interaction between the immune system and malignant tumors. Among them, interleukin-10 (IL-10) is a multifunctional anti-inflammatory cytokine mainly produced by immune cells. The correlation between gastric cancer and T/C single nucleotide polymorphism (SNP) of interleukin-10 (IL-10) promoter-819(rs1800871)was opaque and remained to be determined. We aim to explore the pertinence of gastric cancer and SNP of interleukin 10-819 by meta-analysis via five statistical models. METHODS: Databases including PubMed, Cochrane Library, Embase, the Scopus, and Google Scholars were comprehensively retrieved for the eligible studies on the related topic from inception to March 2022. Odds ratios (ORs) were generated for dichotomous variants by meta-analysis in each model via STATA 17.0 MP. The statistical models comprised recessive model, over-dominant model, allele model, co-dominant model and dominant model. Subgroup analysis was performed to investigate the difference across races as well as the source of heterogeneity if necessary. RESULTS: Eventually a total of 15 articles reporting 7779 patients were enrolled in our study. There were 2383 patients and 5396 controls, collectively. There was no correlation between gastric cancer and IL-10 819 in recessive model, co-dominant model or dominant model, and subgroup analysis showed that Asian, Latin American and Caucasian had no correlation with the risk of gastric cancer. In the allelic model, there was significant correlation between gastric cancer and IL-10 819 (OR = 3.96%, 95%CI: 3.28 to 3.78). In the over-dominant model, there is no correlation between gastric cancer and IL-10 819, but subgroup analysis uncovered significant vulnerability of Asian people with regard to gastric cancer. CONCLUSIONS: In our study, both Asians, Latin Americans, and Europeans showed an increased risk of gastric cancer in the allelic model, whereas only Asians showed significant susceptibility in the super dominant model. Of course, more large cohort studies are needed to confirm our results.


Assuntos
Polimorfismo de Nucleotídeo Único , Neoplasias Gástricas , Humanos , Predisposição Genética para Doença , Interleucina-10/genética , Fatores de Risco , Neoplasias Gástricas/genética
3.
J Comput Assist Tomogr ; 48(3): 491-497, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38157266

RESUMO

OBJECTIVE: Salivary gland lesions show overlapping morphological findings and types of time/intensity curves. This research aimed to evaluate the role of 2-phase multislice spiral computed tomography (MSCT) texture analysis in differentiating between benign and malignant salivary gland lesions. METHODS: In this prospective study, MSCT was carried out on 90 patients. Each lesion was segmented on axial computed tomography (CT) images manually, and 33 texture features and morphological CT features were assessed. Logistic regression analysis was used to confirm predictors of malignancy ( P < 0.05 was considered to be statistically significant), followed by receiver operating characteristics analysis to assess the diagnostic performance. RESULTS: Univariate logistic regression analysis revealed that morphological CT features (shape, size, and invasion of adjacent tissues) and 17 CT texture parameters had significant differences between benign and malignant lesions ( P < 0.05). Multivariate binary logistic regression demonstrated that shape, invasion of adjacent tissues, entropy, and inverse difference moment were independent factors for malignant tumors. The diagnostic accuracy values of multivariate binary logistic models based on morphological parameters, CT texture features, and a combination of both were 87.8%, 90%, and 93.3%, respectively. CONCLUSIONS: Two-phase MSCT texture analysis was conducive to differentiating between malignant and benign neoplasms in the salivary gland, especially when combined with morphological CT features.


Assuntos
Neoplasias das Glândulas Salivares , Humanos , Feminino , Masculino , Neoplasias das Glândulas Salivares/diagnóstico por imagem , Neoplasias das Glândulas Salivares/patologia , Pessoa de Meia-Idade , Diagnóstico Diferencial , Adulto , Idoso , Estudos Prospectivos , Adulto Jovem , Adolescente , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Sensibilidade e Especificidade , Tomografia Computadorizada por Raios X/métodos , Idoso de 80 Anos ou mais , Reprodutibilidade dos Testes , Tomografia Computadorizada Multidetectores/métodos , Tomografia Computadorizada Espiral/métodos , Glândulas Salivares/diagnóstico por imagem
4.
Environ Sci Technol ; 57(7): 2826-2836, 2023 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-36775915

RESUMO

In vivo tracking of persistent organic pollutants (POPs) is of great significance for assessing their risks to the ecological environment and human health. However, existing in vivo POPs detection methods are limited by the lethal sampling of living organisms, complex sample preparation processes, or bulky testing equipment. Photoelectrochemical (PEC) sensing with the merits of high sensitivity and simple equipment is a fast-developed method for in vivo analysis. A major obstacle for in vivo PEC sensors is the separated implantation of multiple electrodes and a light source, which raises concerns like multielectrode biofouling and electroactive molecules interference in the complex environment, uncertain electrode implant distance, and multiple insertion operations. Here, a coaxially implanted photofuel microsensor was developed by hiding the optical fiber-based photoanode inside the glass capillary-based biocathode, and the model target PCB77 can be detected with an ultralow detection limit (2.8 fg/mL). This unique photoanode-biocathode-light source integrated structure ensures excellent selectivity, good antifouling ability and biocompatibility, high accuracy, and less implant mechanical damage. Combined with a handheld pH meter, our sensor achieved convenient and direct tracking of the bioaccumulation levels of PCB77 in freely swimming fish.


Assuntos
Técnicas Biossensoriais , Poluentes Ambientais , Humanos , Poluentes Orgânicos Persistentes , Poluentes Ambientais/análise , Eletrodos , Técnicas Eletroquímicas/métodos , Limite de Detecção
5.
Int J Mol Sci ; 24(5)2023 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-36902425

RESUMO

Skeletal muscle, as a regenerative organization, plays a vital role in physiological characteristics and homeostasis. However, the regulation mechanism of skeletal muscle regeneration is not entirely clear. miRNAs, as one of the regulatory factors, exert profound effects on regulating skeletal muscle regeneration and myogenesis. This study aimed to discover the regulatory function of important miRNA miR-200c-5p in skeletal muscle regeneration. In our study, miR-200c-5p increased at the early stage and peaked at first day during mouse skeletal muscle regeneration, which was also highly expressed in skeletal muscle of mouse tissue profile. Further, overexpression of miR-200c-5p promoted migration and inhibited differentiation of C2C12 myoblast, whereas inhibition of miR-200c-5p had the opposite effect. Bioinformatic analysis predicted that Adamts5 has potential binding sites for miR-200c-5p at 3'UTR region. Dual-luciferase and RIP assays further proved that Adamts5 is a target gene of miR-200c-5p. The expression patterns of miR-200c-5p and Adamts5 were opposite during the skeletal muscle regeneration. Moreover, miR-200c-5p can rescue the effects of Adamts5 in the C2C12 myoblast. In conclusion, miR-200c-5p might play a considerable function during skeletal muscle regeneration and myogenesis. These findings will provide a promising gene for promoting muscle health and candidate therapeutic target for skeletal muscle repair.


Assuntos
Proteína ADAMTS5 , MicroRNAs , Mioblastos , Animais , Camundongos , Proteína ADAMTS5/metabolismo , Diferenciação Celular , Linhagem Celular , Proliferação de Células/genética , MicroRNAs/genética , Desenvolvimento Muscular/genética , Músculo Esquelético/metabolismo , Mioblastos/metabolismo
6.
Nat Mater ; 18(5): 482-488, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30886399

RESUMO

In two-dimensional (2D) systems, high mobility is typically achieved in low-carrier-density semiconductors and semimetals. Here, we discover that the nanobelts of Weyl semimetal NbAs maintain a high mobility even in the presence of a high sheet carrier density. We develop a growth scheme to synthesize single crystalline NbAs nanobelts with tunable Fermi levels. Owing to a large surface-to-bulk ratio, we argue that a 2D surface state gives rise to the high sheet carrier density, even though the bulk Fermi level is located near the Weyl nodes. A surface sheet conductance up to 5-100 S per □ is realized, exceeding that of conventional 2D electron gases, quasi-2D metal films, and topological insulator surface states. Corroborated by theory, we attribute the origin of the ultrahigh conductance to the disorder-tolerant Fermi arcs. The evidenced low-dissipation property of Fermi arcs has implications for both fundamental study and potential electronic applications.

7.
BMC Cancer ; 20(1): 533, 2020 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-32513144

RESUMO

BACKGROUND: Accurate diagnosis of early lung cancer from small pulmonary nodules (SPN) is challenging in clinical setting. We aimed to develop a radiomic nomogram to differentiate lung adenocarcinoma from benign SPN. METHODS: This retrospective study included a total of 210 pathologically confirmed SPN (≤ 10 mm) from 197 patients, which were randomly divided into a training dataset (n = 147; malignant nodules, n = 94) and a validation dataset (n = 63; malignant nodules, n = 39). Radiomic features were extracted from the cancerous volumes of interest on contrast-enhanced CT images. The least absolute shrinkage and selection operator (LASSO) regression was used for data dimension reduction, feature selection, and radiomic signature building. Using multivariable logistic regression analysis, a radiomic nomogram was developed incorporating the radiomic signature and the conventional CT signs observed by radiologists. Discrimination and calibration of the radiomic nomogram were evaluated. RESULTS: The radiomic signature consisting of five radiomic features achieved an AUC of 0.853 (95% confidence interval [CI]: 0.735-0.970), accuracy of 81.0%, sensitivity of 82.9%, and specificity of 77.3%. The two conventional CT signs achieved an AUC of 0.833 (95% CI: 0.707-0.958), accuracy of 65.1%, sensitivity of 53.7%, and specificity of 86.4%. The radiomic nomogram incorporating the radiomic signature and conventional CT signs showed an improved AUC of 0.857 (95% CI: 0.723-0.991), accuracy of 84.1%, sensitivity of 85.4%, and specificity of 81.8%. The radiomic nomogram had good calibration power. CONCLUSION: The radiomic nomogram might has the potential to be used as a non-invasive tool for individual prediction of SPN preoperatively. It might facilitate decision-making and improve the management of SPN in the clinical setting.


Assuntos
Adenocarcinoma de Pulmão/diagnóstico , Processamento de Imagem Assistida por Computador , Neoplasias Pulmonares/diagnóstico , Nomogramas , Tomografia Computadorizada por Raios X , Adenocarcinoma de Pulmão/patologia , Adenocarcinoma de Pulmão/cirurgia , Adulto , Tomada de Decisão Clínica/métodos , Feminino , Humanos , Pulmão/diagnóstico por imagem , Pulmão/patologia , Pulmão/cirurgia , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/cirurgia , Masculino , Pessoa de Meia-Idade , Pneumonectomia , Período Pré-Operatório , Estudos Retrospectivos
8.
J Comput Assist Tomogr ; 44(1): 90-94, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31939888

RESUMO

OBJECTIVE: This study aimed to determine the potential of radiomic features extracted from preoperative computed tomography to discriminate malignant from benign indeterminate small (≤10 mm) pulmonary nodules. METHODS: A total of 197 patients with 210 nodules who underwent surgical resections between January 2011 and March 2017 were analyzed. Three hundred eighty-five radiomic features were extracted from the computed tomographic images. Feature selection and data dimension reduction were performed using the Kruskal-Wallis test, Spearman correlation analysis, and principal component analysis. The random forest was used for radiomic signature building. The receiver operating characteristic curve analysis was used to evaluate the model performance. RESULTS: Fifteen principal component features were selected for modeling. The area under the curve, sensitivity, specificity, and accuracy of the prediction model were 0.877 (95% confidence interval [CI], 0.795-0.959), 81.8% (95% CI, 72.0%-90.9%), 77.4% (95% CI, 63.9%-89.3%), and 80.0% (95% CI, 72.0%-86.7%) in the validation cohort, respectively. CONCLUSIONS: Computed tomography-based radiomic features showed good discriminative power for benign and malignant indeterminate small pulmonary nodules.


Assuntos
Interpretação de Imagem Assistida por Computador/métodos , Neoplasias Pulmonares/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Adolescente , Adulto , Idoso , Estudos de Viabilidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise de Componente Principal , Curva ROC , Estudos Retrospectivos , Sensibilidade e Especificidade , Adulto Jovem
9.
Altern Ther Health Med ; 26(4): 43-49, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31634876

RESUMO

BACKGROUND: Chemotherapy-induced peripheral neuropathy (CIPN) is a common troublesome side effect and affects long-term activities of daily living. This neuropathic disorder is still difficult to treat with current clinical treatments. The aim of this study was to investigate and offer an updated perspective of complementary therapies for CIPN. METHODS: This review included current databases, including PubMed, Embase, the Cochrane Database, Google Scholar, and Ovid Medline, published up to May 2019 in the English language, to summarize the role of nutrient supplements in CIPN, based on evidence from both animal and clinical studies. RESULTS: A total of 58 studies were included in this review. There were 19 preclinical studies that reported mechanisms of effects and 31 clinical studies corroborated preclinical findings, including 22 randomized controlled trials and 3085 patients with CIPN. Interventions included vitamin E, vitamin B complex, glutamine, acetyl-L-carnitine, alpha lipoic acid, glutathione, omega-3 fatty acids, and calcium/magnesium (Ca2+/Mg2+). The administration of various nutrients remains inconsistent, and limited evidence of effective ones for treating CIPN is available. However, glutamine and omega-3 fatty acids present potential as treatment options for CIPN. The evidence on vitamin E and vitamin B complex is inconclusive, and some forms of vitamin B, such as B6 or B12, await confirmation of their potential to offer protection from CIPN. Less robust evidence was found for nutrients such as acetyl-L-carnitine, α-Lipoic acid, glutathione, and Ca2+/Mg2+ for CIPN. CONCLUSION: Nutritional therapists seem to recommend nutrient supplements as potential anti-inflammatory and neuroprotective agents for both the prevention and management of CIPN. An understanding of this evolving literature is useful in exploring these therapies with patients who are considering using them. However, their effects against CIPN are still controversial due to the undetermined neuropathic mechanisms of different antineoplastic agents and complex drug interactions. Further research on these agents is warranted.


Assuntos
Antineoplásicos/efeitos adversos , Suplementos Nutricionais , Doenças do Sistema Nervoso Periférico/terapia , Vitaminas/uso terapêutico , Atividades Cotidianas , Animais , Antineoplásicos/uso terapêutico , Humanos , Doenças do Sistema Nervoso Periférico/induzido quimicamente , Complexo Vitamínico B
10.
J Cell Biochem ; 120(6): 9648-9655, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30520122

RESUMO

Asthma is characterized by airway inflammatory infiltration, which leads to airway remodeling and airway hyperreactivity. Coleus forskohlii (CFK) has been used to treat asthma, however, the mechanism involved is not clear. To explore the antiasthma mechanism of extracts of Coleus forskohlii (ECFK), guinea pigs were administered with a spray of phosphoric acid histamine, and rats were sensitized with ovalbumin (OVA). Hematoxylin and eosin staining (H&E) were used to evaluate pathological changes in lung tissue. Enzyme-linked immunosorbent assay (ELISA) was used to determine cytokine levels in serum and bronchoalveolar lavage fluid (BALF). Immunohistochemistry and Western blot analysis were used to assess the expression of intercellular cell adhesion molecule-1 (ICAM-1), phosphorylation of p65 (p-p65), matrix metallopeptidase 9 (MMP-9), and tissue inhibitor of metalloproteinase 1 (TIMP-1). After ECFK treatment, the asthma incubation period of guinea pigs was significantly prolonged. The H&E results showed that the number of eosinophils in the 12.8 g/kg ECFK group was significantly lower when compared with the control group. Moreover, ELISA results demonstrated that interleukin (IL)-4, IL-5, and IL-17 in serum and BALF were significantly decreased, and interferon-γ (IFN-γ) and IL-10 were increased after ECFK treatment. In addition, ECFK treatment resulted in downregulation of ICAM-1, p-p65, MMP-9, and TIMP-1 in lung tissue after being sensitized by OVA. In conclusion, our findings indicated that ECFK significantly alleviated OVA-induced inflammatory infiltration and airway remodeling in asthma. This study laid a theoretical foundation for the clinical use of ECFK.


Assuntos
Asma/tratamento farmacológico , Tosse/tratamento farmacológico , Matriz Extracelular/metabolismo , Extratos Vegetais/farmacologia , Plectranthus/química , Remodelação das Vias Aéreas/efeitos dos fármacos , Animais , Asma/metabolismo , Tosse/metabolismo , Citocinas/metabolismo , Cobaias , Inflamação/tratamento farmacológico , Masculino , Extratos Vegetais/química , Ratos , Ratos Sprague-Dawley
11.
Opt Express ; 27(12): A936-A952, 2019 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-31252866

RESUMO

Due to the quantum properties of light, solar background radiation (SBR) is the main source of noise in daytime wind observations of spaceborne Doppler wind lidars (DWLs). In previous works, the impact of SBR on the observation accuracy of spaceborne lidars was assessed mainly using the default or worst-case scenarios. We assessed the impact of SBR on the observations of spaceborne DWLs using the global distributions of SBR in summer and winter, which were obtained based on their orbit parameters, view geometry and optical parameters. Three experiments illustrate that the uncertainty in wind observations increases with an increase in the quantiles of SBR. The uncertainties of the whole profiles of wind are greater than 2 m s-1 in the troposphere and 3 m s-1 in the stratosphere when the quantile of the SBR is greater than 85% in summer and 95% in winter, which do not satisfy the accuracy expectations of the European Space Agency (ESA) for spaceborne DWLs. The facts indicate that the impact of SBR cannot be negligible for the observations of spaceborne DWLs. Based on the orbit parameters, view geometry, and optical parameters of new spaceborne DWLs, engineers can assess the impact of SBR on the accuracy of wind observations from a global perspective using the method proposed in this paper.

12.
Appl Opt ; 57(31): 9471-9479, 2018 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-30461995

RESUMO

The properties for six typical land cover types and three sky conditions were derived in this paper, which allows to make seasonal upper estimations of solar background radiation for a given atmospheric scenario. Solar background noise can be derived from the estimations for a spaceborne lidar based on optical parameters. Comparisons among simulated solar background noise and measurements of Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and a Moderate Resolution Imaging Spectroradiometer (MODIS) demonstrate the feasibility of this method. The upper estimates of solar background radiation can be used for lidar engineers to assess the upper estimates of solar background noise for given atmospheric scenarios, which would be a step forward in comparison with using the worst-case scenario everywhere.

13.
Pharmacology ; 102(1-2): 58-66, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29879712

RESUMO

AIMS: The study aimed to investigate the molecular mechanism of inhibition of proliferation and apoptosis induction by galangin against MCF-7 human breast cancer cells. METHODS: Cell Counting Kit-8 assay was used to assess cell viability and flow cytometry was used to detect cell apoptosis. The expression level of apoptosis-related proteins (cleaved-caspase-9, cleaved-caspase-8, cleaved-caspase-3, Bad, cleaved-Bid, Bcl-2, Bax, p-phosphatidylinositol 3-kinase [PI3K], and p-Akt) and cell cycle-related proteins (cyclin D3, cyclin B1, cyclin-dependent kinases CDK1, CDK2, CDK4, p21, p27, p53) were evaluated by Western blotting. RESULTS: Galangin increased the expression of Bax and decreased the expression of Bcl-2 in a concentration-dependent manner, inhibited cell viability, and induced apoptosis. Meanwhile, the expression of cleavage of caspase-9, caspase-8, caspase-3, Bid, and Bad increased significantly while the expression of p-PI3K and p-Akt proteins decreased. In addition, the protein levels of cyclin D3, cyclin B1, CDK1, CDK2, and CDK4 were downregulated while the expression levels of p21, p27, and p53 were upregulated significantly. CONCLUSION: Galangin could suppress the viability of MCF-7 cells and induce cell apoptosis via the mitochondrial pathway and PI3K/Akt inhibition as well as cell cycle arrest.


Assuntos
Proteínas Reguladoras de Apoptose/biossíntese , Apoptose/efeitos dos fármacos , Proteínas de Ciclo Celular/biossíntese , Flavonoides/farmacologia , Mitocôndrias/metabolismo , Inibidores de Fosfoinositídeo-3 Quinase , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Humanos , Fosforilação/efeitos dos fármacos
14.
Mediators Inflamm ; 2018: 9830939, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29713241

RESUMO

Diabetes mellitus (DM) is one of the most familiar chronic diseases threatening human health. Recent studies have shown that the development of diabetes is closely related to an imbalance of the gut microbiota. Accordingly, there is increasing interest in how changes in the gut microbiota affect diabetes and its underlying mechanisms. Immunomodulatory cells play important roles in maintaining the normal functioning of the human immune system and in maintaining homeostasis. Intestinal immunomodulatory cells (IICs) are located in the intestinal mucosa and are regarded as an intermediary by which the gut microbiota affects physiological and pathological properties. Diabetes can be regulated by IICs, which act as a bridge linking the gut microbiota and DM. Understanding this bridge role of IICs may clarify the mechanisms by which the gut microbiota contributes to DM. Based on recent research, we summarize this process, thereby providing a basis for further studies of diabetes and other similar immune-related diseases.


Assuntos
Diabetes Mellitus/metabolismo , Animais , Diabetes Mellitus/imunologia , Microbioma Gastrointestinal/fisiologia , Humanos , Mucosa Intestinal/microbiologia , Intestinos/imunologia , Intestinos/microbiologia , Linfócitos T/imunologia
15.
Nano Lett ; 17(4): 2211-2219, 2017 04 12.
Artigo em Inglês | MEDLINE | ID: mdl-28244324

RESUMO

Three-dimensional topological Dirac semimetals have hitherto stimulated unprecedented research interests as a new class of quantum materials. Breaking certain types of symmetries has been proposed to enable the manipulation of Dirac fermions, and that was soon realized by external modulations such as magnetic fields. However, an intrinsic manipulation of Dirac states, which is more efficient and desirable, remains a significant challenge. Here, we report a systematic study of quasi-particle dynamics and band evolution in Cd3As2 thin films with controlled chromium (Cr) doping by both magneto-infrared spectroscopy and electrical transport. We observe the √B relation of inter-Landau-level resonance in Cd3As2, an important signature of ultrarelativistic massless state inaccessible in previous optical experiments. A crossover from quantum to quasi-classical behavior makes it possible to directly probe the mass of Dirac fermions. Importantly, Cr doping allows for a Dirac mass acquisition and topological phase transition enabling a desired dynamic control of Dirac fermions. Corroborating with the density-functional theory calculations, we show that the mass generation can be explained by the explicit C4 rotation symmetry breaking and the resultant Dirac gap engineering through Cr substitution for Cd atoms. The manipulation of the system symmetry and Dirac mass in Cd3As2 thin films provides a tuning knob to explore the exotic states stemming from the parent phase of Dirac semimetals.

16.
J BUON ; 23(5): 1297-1301, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30570850

RESUMO

PURPOSE: The 21-gene recurrence score (RS) assay predicts relapse of estrogen receptor-positive and lymph node-negative breast cancer more accurately than traditional markers; however, whether this assay can be regarded as a molecular marker of other types of breast cancer is unclear. We aimed to identify the effect of 21-gene recurrence score assay in non-estrogen receptor-positive and lymph node-negative breast cancer. METHODS: We analyzed 21-gene expression by quantitative real-time PCR (qRT-PCR) in 100 cases of breast cancer tissues and followed up for 5 years to investigate the prognostic significance in non-estrogen receptor-positive and lymph node-negative breast cancer. Also, the correlation between RS and the clinicopathological features were analyzed. Adjuvant online (AOL) database was used for the analyses in the present study. RESULTS: The cases were classified as RS low (n=52), moderate (n=22) and high (n=26) risk. The RS based on the21-gene assay was not correlated with age, tumor size, histological grade, and lymph node and estrogen receptor/progesterone receptor (ER/PR) status; however, there was significant correlation with Her-2 status. The 5-year recurrence rates were 1.92%, 4.55% and 15.38% in the low, moderate and high-risk groups, respectively. In addition, there was significant difference between the low-high groups (p<0.05). Furthermore, the consistency of the prognosis predicted by the AOL system was 56% and 59% in the RS moderate-high risk and low risk groups, respectively. CONCLUSIONS: The 21-gene RS assay was a prognostic indicator for patients with non-ER-positive and lymph node-negative breast cancer. In addition, our results coincided with those obtained using the AOL system.


Assuntos
Biomarcadores Tumorais/genética , Neoplasias da Mama/terapia , Perfilação da Expressão Gênica , Linfonodos/patologia , Recidiva Local de Neoplasia/diagnóstico , Receptores de Estrogênio/metabolismo , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Terapia Combinada , Feminino , Seguimentos , Humanos , Linfonodos/metabolismo , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/genética , Prognóstico , Receptor ErbB-2/metabolismo , Receptores de Progesterona/metabolismo
17.
Zhongguo Zhong Yao Za Zhi ; 43(18): 3748-3755, 2018 Sep.
Artigo em Zh | MEDLINE | ID: mdl-30384542

RESUMO

An ultra-performance liquid chromatography-tandem mass spectrometric method (UPLC-MS/MS) was developed in this study to simultaneously determine the contents of eight effective constituents in rat plasma, including baicalin, wogonoside, baicalein, liquiritin, glycyrrhizic acid, berberine hydrochloride, saikosaponin a and saikosaponin d in plasma of gastric ulcer rats, and investigate the pharmacokinetics of Modified Xiaochaihu Granules. Chromatographic separation was conducted on Zorbax SB-C18 column (2.1 mm×100 mm, 1.8 µm) with acetonitrile -0.1% formic acid aqueous solution as the mobile phase for gradient elution, at a flow rate of 0.4 mL·min⁻¹ and column temperature of 40 °C. Detection was performed in the multiple reaction monitoring (MRM) mode with ESI ion source. All calibration curves showed good linearity (r>0.996) over a wide concentration range for all constituents. RSDs of intra-day and inter-day precision were all within 15% and the extraction recoveries of all the constituents were in the range of 81.92% to 104.8%. The time to peak (tmax) of these eight constituents was (2.69±2.02), (5.17±2.04), (0.25±0), (0.83±0.26), (0.92±0.20), (0.92±0.20), (0.58±0.20), and (0.083±0) h, respectively; the half-life (t1/2) of them was (7.85±0.34), (10.16±2.21), (6.79±0.21), (8.32±0.48), (11.05±1.78), (11.56±3.46), (15.30±1.84), and (5.54±1.91) h, respectively; the peak concentration (Cmax) of them was (55.02±1.67), (213.66±4.62), (62.61±0.69), (68.43±1.42), (62.22±0.39), (30.17±1.89), (61.79±4.81), and (38.02±1.75) µg·L⁻¹, respectively. This established method is simple and accurate with good repeatability and strong specificity, which could provide modern experimental basis for modified Xiaochaihu granules in clinical treatment of gastric ulcer.


Assuntos
Medicamentos de Ervas Chinesas/farmacocinética , Úlcera Gástrica/tratamento farmacológico , Administração Oral , Animais , Cromatografia Líquida de Alta Pressão , Compostos Fitoquímicos/farmacocinética , Plasma/química , Ratos , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem
18.
Zhongguo Zhong Yao Za Zhi ; 43(8): 1692-1700, 2018 Apr.
Artigo em Zh | MEDLINE | ID: mdl-29751718

RESUMO

To conduct the studies on serum pharmacochemistry of effective parts of modified Xiaochaihu Tang for treatment of gastric ulcer by using chromatography-mass spectrometry. Absolute ethyl alcohol induced-gastric ulcer model of mouse was used in this study to investigate the pharmacology of modified Xiaochaihu Tang and its effective parts. Both groups could significantly decrease the absolute ethyl alcohol induced-ulcer. Gasphase-mass spectrometry (GC-MS) was used to detect chemical compositions of volatile fractions and the drug components after gastric administration. A total of 63 compounds were identified in extracts, accounting for more than 93% of the all volatile oil, including 23.51% α-curcumene, 11.96% zingiberene, 9.56% curzerene, 6.54% ß-sesquinene, 4.77% camphene, and 6 prototype components were also detected in serum for gastric ulcer model. In liquid chromatography-mass spectrometry (LC-MS), a total of 17 compounds were identified in extracts, 6 prototype components and 2 metabolites (3,5-O-feruloylquinic acid and palmatine) were obtained in serum. In a conclusion, this study provides an important scientific basis for identifying the active ingredients in modified Xiaochaihu Tang, and also helps to reveal the pharmacological effect of modified Xiaochaihu Tang for treatment of gastric ulcer.


Assuntos
Medicamentos de Ervas Chinesas , Úlcera Gástrica , Animais , Cromatografia Líquida , Camundongos , Óleos Voláteis , Espectrometria de Massas em Tandem
19.
Mol Cancer ; 16(1): 39, 2017 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-28209170

RESUMO

BACKGROUND: Although the prognosis of gastric cancer patients have a favorable progression, there are some patients with unusual patterns of locoregional and systemic recurrence. Therefore, a better understanding of early molecular events of the disease is needed. Current evidences demonstrate that long noncoding RNAs (lncRNAs) may be an important class of functional regulators involved in human gastric cancers development. Our previous studies suggest that HOTAIR contributes to gastric cancer development, and the overexpression of HOTAIR predicts a poor prognosis. In this study, we investigated the characteristic of the LncRNA FEZF1-AS1 in gastric cancer. METHODS: QRT-PCR was used to detect the expression of FEZF1-AS1 in gastric cancer tissues and cells. MTT assays, clonogenic survival assays and nude mouse xenograft model were used to examine the tumorigenesis function of FEZF1-AS1 in vitro and in vivo. Bioinformatics analysis were used to select downstream target genes of FEZF1-AS1. Cell cycle analysis, ChIP, RIP,RNA Pulldown assays were examined to dissect molecular mechanisms. RESULTS: In this study, we reported that FEZF1-AS1, a 2564 bp RNA, was overexpressed in gastric cancer, and upregulated FEZF1-AS1 expression indicated larger tumor size and higher clinical stage; additional higher expression of FEZF1-AS1 predicted poor prognosis. Further experiments revealed that knockdown FEZF1-AS1 significantly inhibited gastric cancer cells proliferation by inducing G1 arrest and apoptosis, whereas endogenous expression FEZF1-AS1 promoted cell growth. Additionally, RIP assay and RNA-pulldown assay evidenced that FEZF1-AS1 could epigenetically repress the expression of P21 via binding with LSD1, the first discovered demethylase. ChIP assays demonstrated that LSD1 could directly bind to the promoter of P21, inducing H3K4me2 demethylation. CONCLUSION: In summary, these data demonstrated that FEZF1-AS1 could act as an "oncogene" for gastric cancer partly through suppressing P21 expression; FEZF1-AS1 may be served as a candidate prognostic biomarker and target for new therapies of gastric cancer patients.


Assuntos
Inibidor de Quinase Dependente de Ciclina p21/genética , Histona Desmetilases/genética , Histonas/metabolismo , RNA Longo não Codificante/genética , Neoplasias Gástricas/patologia , Animais , Linhagem Celular Tumoral , Proliferação de Células , Desmetilação , Epigênese Genética , Feminino , Regulação Neoplásica da Expressão Gênica , Histona Desmetilases/metabolismo , Humanos , Masculino , Camundongos , Estadiamento de Neoplasias , Transplante de Neoplasias , Prognóstico , Neoplasias Gástricas/genética , Neoplasias Gástricas/metabolismo
20.
Artigo em Inglês | MEDLINE | ID: mdl-28438933

RESUMO

Pyrazinamide (PZA), an indispensable component of modern tuberculosis treatment, acts as a key sterilizing drug. While the mechanism of activation of this prodrug into pyrazinoic acid (POA) by Mycobacterium tuberculosis has been extensively studied, not all molecular determinants that confer resistance to this mysterious drug have been identified. Here, we report how a new PZA resistance determinant, the Asp67Asn substitution in Rv2783, confers M. tuberculosis resistance to PZA. Expression of the mutant allele but not the wild-type allele in M. tuberculosis recapitulates the PZA resistance observed in clinical isolates. In addition to catalyzing the metabolism of RNA and single-stranded DNA, Rv2783 also metabolized ppGpp, an important signal transducer involved in the stringent response in bacteria. All catalytic activities of the wild-type Rv2783 but not the mutant were significantly inhibited by POA. These results, which indicate that Rv2783 is a target of PZA, provide new insight into the molecular mechanism of the sterilizing activity of this drug and a basis for improving the molecular diagnosis of PZA resistance and developing evolved PZA derivatives to enhance its antituberculosis activity.


Assuntos
Antituberculosos/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Pirazinamida/análogos & derivados , Cromatografia Líquida de Alta Pressão , DNA de Cadeia Simples/genética , Farmacorresistência Bacteriana , Testes de Sensibilidade Microbiana , Mycobacterium tuberculosis/enzimologia , Pirazinamida/farmacologia , Pirofosfatases/genética
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