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1.
Leukemia ; 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38750139

RESUMO

The clinical implications of CSF-ctDNA positivity in newly diagnosed diffuse large B cell lymphoma (ND-DLBCL) remains largely unexplored. One hundred ND-DLBCL patients were consecutively enrolled as training cohort and another 26 ND-DLBCL patients were prospectively enrolled in validation cohort. CSF-ctDNA positivity (CSF(+)) was identified in 25 patients (25.0%) in the training cohort and 7 patients (26.9%) in the validation cohort, extremely higher than CNS involvement rate detected by conventional methods. Patients with mutations of CARD11, JAK2, ID3, and PLCG2 were more predominant with CSF(+) while FAT4 mutations were negatively correlated with CSF(+). The downregulation of PI3K-AKT signaling, focal adhesion, actin cytoskeleton, and tight junction pathways were enriched in CSF(+) ND-DLBCL. Furthermore, pretreatment CSF(+) was significantly associated with poor outcomes. Three risk factors, including high CSF protein level, high plasma ctDNA burden, and involvement of high-risk sites were used to predict the risk of CSF(+) in ND-DLBCL. The sensitivity and specificity of pretreatment CSF-ctDNA to predict CNS relapse were 100% and 77.3%. Taken together, we firstly present the prevalence and the genomic and transcriptomic landscape for CSF-ctDNA(+) DLBCL and highlight the importance of CSF-ctDNA as a noninvasive biomarker in detecting and monitoring of CSF infiltration and predicting CNS relapse in DLBCL.

2.
Hortic Res ; 11(3): uhae028, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38559468

RESUMO

Saline-alkali is an important abiotic stressor influencing tomato production. Exogenous methyl jasmonate (MeJA) is well known to increase tomato resistance to a variety of stresses, although its exact mechanism is yet unknown. In this study we confirmed that 22.5 µmol/l MeJA could significantly improve the saline-alkali stress resistance of tomato. Saline-alkali (300 mM) stress increased the endogenous MeJA and jasmonic acid (JA) contents of tomato by 18.8 and 13.4%, respectively. Exogenous application of 22.5 µmol/l MeJA increased the endogenous MeJA and JA contents in tomato by 15.2 and 15.9%, respectively. Furthermore, we found an important transcription factor, SlWRKY80, which responded to MeJA, and constructed its overexpressing and knockout lines through genetic transformation. It was found that SlWRKY80 actively regulated tomato resistance to saline-alkali stress, and the spraying of exogenous MeJA (22.5 µmol/l) reduced the sensitivity of SlWRKY80 knockout lines to saline-alkali stress. The SlWRKY80 protein directly combines with the promoter of SlSPDS2 and SlNHX4 to positively regulate the transcription of SlSPDS2 and SlNHX4, thereby promoting the synthesis of spermidine and Na+/K+ homeostasis, actively regulating saline-alkali stress. The augmentation of JA content led to a notable reduction of 70.6% in the expression of SlJAZ1, and the release of the SlWRKY80 protein interacting with SlJAZ1. In conclusion, we revealed the mechanism of exogenous MeJA in tomato stress resistance through multiple metabolic pathways, elucidated that exogenous MeJA further promotes spermidine synthesis and Na+/K+ homeostasis by activating the expression of SlWRKY80, which provides a new theoretical basis for the study of the JA stress resistance mechanism and the production of tomato.

3.
Plant J ; 118(6): 1774-1792, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38468425

RESUMO

Saline-alkali stress is an important abiotic stress factor affecting tomato (Solanum lycopersicum L.) plant growth. Although the involvement of the tomato SlWRKY gene family in responses to saline-alkali stress has been well established, the mechanism underlying resistance to saline-alkali stress remains unclear. In this study, we investigated the role of SlWRKY81 in conferring saline-alkali stress resistance by using overexpression and knockout tomato seedlings obtained via genetic modification. We demonstrated that SlWRKY81 improves the ability of tomato to withstand saline-alkali stress by enhancing antioxidant capacity, root activity, and proline content while reducing malondialdehyde levels. Saline-alkali stress induces an increase in jasmonic acid (JA) content in tomato seedlings, and the SlWRKY81 promoter responds to JA signaling, leading to an increase in SlWRKY81 expression. Furthermore, the interaction between SlJAZ1 and SlWRKY81 represses the expression of SlWRKY81. SlWRKY81 binds to W-box motifs in the promoter regions of SlSPDS2 and SlNHX4, thereby positively regulating their expression. This regulation results in increased spermidine (Spd) content and enhanced potassium (K+) absorption and sodium (Na+) efflux, which contribute to the resistance of tomato to saline-alkali stress. However, JA and SlJAZ1 exhibit antagonistic effects. Elevated JA content reduces the inhibitory effect of SlJAZ1 on SlWRKY81, leading to the release of additional SlWRKY81 protein and further augmenting the resistance of tomato to saline-alkali stress. In summary, the modulation of Spd synthesis and Na+/K+ homeostasis mediated by the interaction between SlWRKY81 and SlJAZ1 represents a novel pathway underlying tomato response to saline-alkali stress.


Assuntos
Ciclopentanos , Regulação da Expressão Gênica de Plantas , Homeostase , Oxilipinas , Proteínas de Plantas , Potássio , Sódio , Solanum lycopersicum , Solanum lycopersicum/genética , Solanum lycopersicum/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Oxilipinas/metabolismo , Ciclopentanos/metabolismo , Potássio/metabolismo , Sódio/metabolismo , Espermidina/metabolismo , Álcalis/metabolismo , Plântula/genética , Plântula/metabolismo , Plântula/fisiologia , Transdução de Sinais
4.
Ann Hematol ; 103(5): 1675-1685, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38228775

RESUMO

Diffuse large B-cell lymphoma (DLBCL) is a severe non-Hodgkin's lymphoma. Life expectancy has improved with rituximab, but cause-specific mortality data is lacking. Using the Surveillance, Epidemiology, and End Results (SEER) database to study 27,449 individuals aged 20-74 years diagnosed with primary DLBCL who received chemotherapy between 2000 and 2019, we calculated standardized mortality rate (SMR) and excess absolute risk (EAR) and examined the connection between age, sex, time after diagnosis, and cause of death. Based on 12,205 deaths, 68.7% were due to lymphoma, 20.1% non-cancer causes, and 11.2% other cancers. Non-cancer mortality rates (SMR 1.2; EAR, 21.5) increased with DLBCL compared to the general population. The leading non-cancer death causes were cardiovascular (EAR, 22.6; SMR, 1.6) and infectious (EAR, 9.0; SMR, 2.9) diseases with DLBCL. Risks for non-cancer death and solid neoplasms are highest within the first diagnosis year, then decrease. Among socioeconomic factors, being white, being married, and having a higher income were favorable factors for reducing non-cancer mortality. To improve survival, close surveillance, assessment of risk factors, and early intervention are needed.


Assuntos
Linfoma Difuso de Grandes Células B , Linfoma não Hodgkin , Humanos , Causas de Morte , Programa de SEER , Linfoma Difuso de Grandes Células B/patologia , Linfoma não Hodgkin/epidemiologia , Rituximab/uso terapêutico
5.
Ann Hematol ; 103(3): 833-841, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37993586

RESUMO

Chronic lymphocytic leukemia (CLL) patients with hepatitis B virus (HBV) infection have a poor prognosis, underlying mechanism remains unclear. NOTCH mutations are frequent in CLL and associated with disease progression and drug resistance. It is also reported to be associated with hepatitis infection in lymphoid malignancies. In order to investigate the relation between the NOTCH pathway and HBV-associated CLL, we studied 98 previously untreated HBV-positive CLL patients and 244 HBV-negative CLL. NOTCH mutations were more frequent in HBV-positive CLL subgroup (p = 0.033). By survival analysis, HBV infection was associated with disease progression and poor survival (p = 0.0099 for overall survival (OS) and p = 0.0446 for time-to-treatment (TTT)). Any lesions of the NOTCH pathway (NOTCH1, NOTCH2, and SPEN) aggravated prognosis. In multivariate analysis, NOTCH mutation retained an independent significance for HBV-infected patients (p = 0.016 for OS and p = 0.023 for TTT). However, HBV positive with NOTCH unmutated had no statistical difference in prognosis compared with HBV-negative patients (p = 0.1706 for OS and p = 0.2387 for TTT), which indicated that NOTCH pathway mutation contributed to inferior prognosis in HBV-infected CLL. In conclusion, a cohort of CLL patients with HBV positive displayed a worse clinical outcome and the status of the NOTCH signaling pathway might play a crucial role.


Assuntos
Hepatite B , Leucemia Linfocítica Crônica de Células B , Humanos , Vírus da Hepatite B , Leucemia Linfocítica Crônica de Células B/patologia , Prognóstico , Mutação , Progressão da Doença , Receptor Notch1/genética
6.
Hepatol Int ; 17(4): 915-926, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37012542

RESUMO

BACKGROUND: The evidence of transcatheter arterial chemoembolization (TACE) plus tyrosine kinase inhibitor and immune checkpoint inhibitor in unresectable hepatocellular carcinoma (HCC) was limited. This study aimed to evaluate the role of TACE plus apatinib (TACE + A) and TACE combined with apatinib plus camrelizumab (TACE + AC) in patients with unresectable HCC. METHODS: This study retrospectively reviewed patients with unresectable HCC who received TACE + A or TACE + AC in 20 centers of China from January 1, 2019 to June 31, 2021. Propensity score matching (PSM) at 1:1 was performed to reduce bias. Treatment-related adverse events (TRAEs), overall survival (OS), progression-free survival (PFS), objective response rate (ORR) and disease control rate (DCR) were collected. RESULTS: A total of 960 eligible patients with HCC were included in the final analysis. After PSM, there were 449 patients in each group, and the baseline characteristics were balanced between two groups. At data cutoff, the median follow-up time was 16.3 (range: 11.9-21.4) months. After PSM, the TACE + AC group showed longer median OS (24.5 vs 18.0 months, p < 0.001) and PFS (10.8 vs 7.7 months, p < 0.001) than the TACE + A group; the ORR (49.9% vs 42.5%, p = 0.002) and DCR (88.4% vs 84.0%, p = 0.003) of the TACE + AC group were also higher than those in the TACE + A group. Fever, pain, hypertension and hand-foot syndrome were the more common TRAEs in two groups. CONCLUSIONS: Both TACE plus apatinib and TACE combined with apatinib plus camrelizumab were feasible in patients with unresectable HCC, with manageable safety profiles. Moreover, TACE combined with apatinib plus camrelizumab showed additional benefit.


Assuntos
Antineoplásicos , Carcinoma Hepatocelular , Quimioembolização Terapêutica , Neoplasias Hepáticas , Humanos , Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/patologia , Estudos Retrospectivos , Antineoplásicos/uso terapêutico , Terapia Combinada
7.
Ann Hematol ; 102(2): 359-367, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36624225

RESUMO

To investigate the prognostic significance of peripheral blood absolute monocyte count (AMC) and lymphocyte to monocyte ratio (LMR) in mucosa-associated lymphoid tissue (MALT) lymphoma, we retrospectively analyzed 316 newly diagnosed patients with MALT lymphoma. The best cut-off value of AMC was 0.6 × 109/L and LMR was 1.8 by x-tile according to progression-free survival (PFS). Multivariate analysis showed that MALT-IPI (p < 0.001), Eastern Cooperative Oncology Group performance status (ECOG PS) (p = 0.010), and LMR (p = 0.003) have independent prognostic significance for PFS, MALT-International Prognostic Index (MALT-IPI) (p = 0.018), ß2-microglobulin (ß2-MG) (p = 0.015), and LMR (p = 0.029) predicted poor overall survival (OS). Receiver-operator characteristic (ROC) curves were used to compare the prognostic prediction capability of MALT-IPI and MALT-IPI-M (MALT-IPI combined with LMR); area under the curves (AUCs) for MALT-IPI-M were larger than that for MALT-IPI both PFS (0.682 vs 0.654) and OS (0.804 vs 0.788). Our results indicated that that low level LMR at diagnosis was associated with inferior prognosis. The new prognostic index, MALT-IPI-M, enabled the risk stratification capability for MALT lymphoma survival.


Assuntos
Linfoma de Zona Marginal Tipo Células B , Monócitos , Humanos , Monócitos/patologia , Prognóstico , Linfoma de Zona Marginal Tipo Células B/diagnóstico , Linfoma de Zona Marginal Tipo Células B/patologia , Estudos Retrospectivos , Linfócitos/patologia , Tecido Linfoide , Mucosa , Contagem de Linfócitos
8.
Br J Haematol ; 196(6): 1353-1361, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34961920

RESUMO

To assess the prognostic significance of immunoglobulin (Ig) paraproteinaemia in mucosa-associated lymphoid tissue (MALT) lymphoma, 218 patients diagnosed with MALT lymphoma were enrolled in this study. Serum Ig paraprotein was detected in 42 of 218 patients (19.3%), mostly IgM-K (15, 35.7%), followed by IgM-L and IgG-L. Advanced age (p = 0.025), poor Eastern Cooperative Oncology Group performance status (p = 0.014), bone marrow involvement (p = 0.019), B symptoms (p = 0.039), advanced disease stage (III-IV) (p < 0.0001), elevated serum ß2-microglobulin level (p < 0.0001), multiple extranodal sites of involvement (p < 0.0001), nodal involvement (p < 0.0001), systemic therapy (p < 0.0001) and higher MALT-lymphoma International Prognostic Index (MALT-IPI) scores (p = 0.001) were significantly associated with the presence of serum Ig paraprotein. Multivariate Cox regression analysis showed that Ig paraproteinaemia was an independent prognostic predictor for inferior progression-free survival (PFS) and overall survival. A new prognostic index based on MALT-IPI and Ig paraproteinaemia, as assessed using receiver operating characteristic curves and the area under the curve statistics, showed better discriminative ability than MALT-IPI in predicting PFS. In conclusion, Ig paraproteinaemia was a promising prognostic predictor for MALT lymphoma. Ig paraproteinaemia together with MALT-IPI might contribute to optimising therapeutic management in clinical practice.


Assuntos
Linfoma de Zona Marginal Tipo Células B , Paraproteinemias , Humanos , Imunoglobulina M , Tecido Linfoide/patologia , Linfoma de Zona Marginal Tipo Células B/tratamento farmacológico , Mucosa/patologia , Paraproteínas , Prognóstico , Estudos Retrospectivos
9.
Biomaterials ; 255: 120157, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32535305

RESUMO

The therapeutic outcome of pancreatic cancer remains unsatisfactory, despite many attempts to improve it. To address this challenge, an oral drug delivery system that spontaneously initiates an effervescent reaction to form gas-bubble carriers is proposed. These carriers concurrently deliver lipophilic paclitaxel (PTX) and hydrophilic gemcitabine (GEM) in the small intestine. The bursting of the bubbles promotes the intestinal absorption of the drugs. The antitumor efficacy of this proposed oral drug delivery system is evaluated in rats with experimentally created orthotopic pancreatic tumors. The combined administration of equivalent amounts of PTX and GEM via the intravenous (i.v.) route, which is clinically used for treating pancreatic cancer, serves as a control. Following oral administration, the lipophilic PTX is initially absorbed through the intestinal lymphatic system and then enters systemic circulation, whereas the hydrophilic GEM is directly taken up into the blood circulation, ultimately accumulating in the tumorous pancreatic tissues. A pharmacokinetic study reveals that the orally delivered formulation has none of the toxic side-effects that are associated with the i.v. injected formulation; changes the pharmacokinetic profiles of the drugs; and increases the bioavailability of PTX. The oral formulation has a greater impact than the i.v. formulation on tumor-specific stromal depletion, resulting in greater inhibition of tumor growth with no evidence of metastatic spread. As well as enhancing the therapeutic efficacy, this unique approach of oral chemotherapy has potential for use on outpatients, greatly improving their quality of life.


Assuntos
Neoplasias Pancreáticas , Qualidade de Vida , Administração Oral , Animais , Linhagem Celular Tumoral , Portadores de Fármacos/uso terapêutico , Sistemas de Liberação de Medicamentos , Interações Hidrofóbicas e Hidrofílicas , Paclitaxel/uso terapêutico , Neoplasias Pancreáticas/tratamento farmacológico , Ratos
10.
Gastroenterol Res Pract ; 2020: 3245359, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32211041

RESUMO

BACKGROUND: Proton pump inhibitor (PPI) and other acid-suppressing drugs are widely used in the treatment of gastrointestinal ulcer, upper gastrointestinal bleeding, gastritis, and gastric cancer (GC). About 80% of GC patients receive acid suppression treatment. PPI suppresses the production of gastric acid by inhibiting the function of H+/K+-ATPase in gastric parietal cells and raises the pH value to achieve therapeutic purposes. Some studies have found that PPI had a certain antitumor effect in the proliferation and apoptosis of tumor cells. But the effects of environmental pH on the growth of GC cells and its mechanism are unknown. Therefore, we hoped to find the effects of culture medium pH on the biological behavior of GC cells by in vitro experiments and provide guidance for the use of acid-suppressing drugs in GC patients. AIMS: We aimed to observe the effects of pH changes in GC cell culture medium on the cell biological behavior of cancer cells and to analyze the potential mechanisms. We hoped to find out the effect of acid suppression on the growth of GC cells. METHODS: The GC cell lines (SGC-7901 and MKN45) were used as the research object. We adjusted the pH value in the cell culture medium to observe the changes in cell viability (MTT), apoptosis (flow cytometry), and invasion (Transwell) at pH 6, pH 7, and pH 8. qRT-PCR and western blot (WB) assays were used to determine the expression changes of genes and proteins (mTOR, AKT, Wnt, Glut, and HIF-1α) at pH 6, pH 7, and pH 8. RESULTS: The results of MTT showed that the viability of SGC-7901 and MKN45 in the pH 8.0 group was significantly weaker than that in the pH 6.0 or pH 7.0 group (P < 0.001). Flow cytometry results showed that the apoptosis of SGC-7901 and MKN45 in the pH 8.0 group was more obvious than that in the pH 6.0 or pH 7.0 group (P < 0.001). Flow cytometry results showed that the apoptosis of SGC-7901 and MKN45 in the pH 8.0 group was more obvious than that in the pH 6.0 or pH 7.0 group (P < 0.001). Flow cytometry results showed that the apoptosis of SGC-7901 and MKN45 in the pH 8.0 group was more obvious than that in the pH 6.0 or pH 7.0 group (α) at pH 6, pH 7, and pH 8. P < 0.001). Flow cytometry results showed that the apoptosis of SGC-7901 and MKN45 in the pH 8.0 group was more obvious than that in the pH 6.0 or pH 7.0 group (. CONCLUSIONS: Compared with the microacid environment, the microalkaline environment inhibited the viability, invasion, and expression of genes and proteins (mTOR, AKT, Wnt, Glut, and HIF-1α) but promoted the apoptosis of GC cells and thus inhibited the growth of GC.α) at pH 6, pH 7, and pH 8.

11.
J Exp Clin Cancer Res ; 38(1): 327, 2019 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-31337431

RESUMO

Malignant tumors are often multifactorial. Epidemiological studies have shown that hyperglycemia raises the prevalence and mortality of certain malignancies, like breast, liver, bladder, pancreatic, colorectal, endometrial cancers. Hyperglycemia can promote the proliferation, invasion and migration, induce the apoptotic resistance and enhance the chemoresistance of tumor cells. This review focuses on the new findings in the relationship between hyperglycemia and tumor development.


Assuntos
Progressão da Doença , Hiperglicemia/metabolismo , Neoplasias/metabolismo , Apoptose/genética , Proliferação de Células/genética , Resistencia a Medicamentos Antineoplásicos/genética , Glucose/metabolismo , Humanos , Hiperglicemia/complicações , Hiperglicemia/patologia , Neoplasias/complicações , Neoplasias/genética , Neoplasias/patologia
12.
Polymers (Basel) ; 10(9)2018 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-30960909

RESUMO

In a corona environment, the initiation and propagation of electrical trees in a polymer matrix originate from the field enhancement effect. Driven by the macroscopic alternating electric field, a weak alternating current (AC) was passed through the decomposition channel of an electrical tree, and a small amount of alternating electric quantity was present on the tip of the electrical tree, resulting in an enhanced local electric field around the tip of the electrical tree. The emissions of electrons accelerated in the enhanced local electric field resulted in the decomposition of the polymer material, stimulating the propagation of the electrical tree. When inorganic nano-particles with high corona resistibility were introduced into the polymer matrix, the nano-particles were aggregately deposited as the polymer material decomposed. The decomposition channel of the electrical tree was blocked and the current passing through the decomposition channel was shut off, eliminating the enhanced local electric field. As a result, the propagation of electrical trees was restrained and an improved corona resistibility was achieved for the polymer/nano-particles composite material.

13.
Food Chem ; 224: 26-31, 2017 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-28159264

RESUMO

To evaluate the structure-activity relationship of 5,7-dihydroxyflavonoids against P. italicum, we tested the antifungal activity of 23 selected 5,7-dihydroxyflavonoids against spore germination of P. italicum, and the effects of hydroxyl group, hydrogenation, methylation and glycosylation on the antifungal activity are explored. C-4'-OH and C-3-OH are active groups for the 5,7-dihydroxyflavonoids against P. italicum. We find that hydrogenation of the C2/C3 bond decreases the antifungal activity of 5,7-dihydroxyflavonoids. Antifungal activity of 5,7-dihydroxyflavonoids against P. italicum was affected by the conjugation site of glycosylation and the class of sugar moiety. The correlation between antifungal activity and the inhibition of respiration of 5,7-dihydroxyflavonoids was further evaluated. We find no significant relationship among the IC50 of 5,7-dihydroxyflavonoids on spore germination and on respiration. Some 5,7-dihydroxyflavonoids even enhance the respiration of P. italicum. This indicate respiration is not the only target for 5,7-dihydroxyflavonoids against P. italicum.


Assuntos
Antifúngicos/química , Flavonoides/química , Penicillium/efeitos dos fármacos , Antifúngicos/farmacologia , Flavonoides/farmacologia , Glicosilação/efeitos dos fármacos , Relação Estrutura-Atividade
14.
Mol Med Rep ; 14(5): 4209-4215, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27634376

RESUMO

This is a retrospective analysis of the clinical effects of transplant of mesenchymal stem cells (MSCs) derived from human umbilical cord-derived MSCs (hUC­MSCs) for the treatment of osteonecrosis of the femoral head (ONFH). The biological characteristics of hUC-MSCs were assessed using flow cytometry. Nine eligible patients were enrolled in the study as they adhered to the Association Research Circulation Osseous (ARCO) classification of stage â…¡­â…¢a, and hUC­MSCs were grafted by intra­arterial infusion. Organize effective perfusion was assessed using the oxygen delivery index (ODI). The results showed that the ODI was increased at three days post­operation. The MRI results revealed that at 12 and 24 months after treatment, the necrotic volume of the femoral heads was significantly reduced. No obvious abnormalities were observed. Taken together, these data indicate that intra­arterially infused hUC­MSCs migrate into the necrotic field of femoral heads and differentiate into osteoblasts, thus improving the necrosis of femoral heads. This finding suggested that intra­arterial infusion of hUC­MSCs MSCs is a feasible and relatively safe method for the treatment of femoral head necrosis.


Assuntos
Necrose da Cabeça do Fêmur/terapia , Cabeça do Fêmur/transplante , Transplante de Células-Tronco Mesenquimais , Osteonecrose/terapia , Adulto , Feminino , Cabeça do Fêmur/fisiopatologia , Necrose da Cabeça do Fêmur/patologia , Seguimentos , Humanos , Masculino , Células-Tronco Mesenquimais/citologia , Pessoa de Meia-Idade , Osteonecrose/patologia , Estudos Retrospectivos , Cordão Umbilical/transplante
15.
Phys Chem Chem Phys ; 18(5): 3482-8, 2016 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-26750979

RESUMO

To restrain the saturation behavior in low voltage cathodoluminescence, a small amount of carbon nano-tubes (CNT) was introduced into the phosphor to form CNT-introduced phosphor material. In the specific working conditions in low voltage cathodoluminescence, the field enhancement effect is initiated in the CNT-introduced phosphor material, and the local electric fields surrounding the top of each CNT is much stronger than the background electric field. The CNTs, with enhanced local electric fields surrounding their tops, play a key role in removing the electrons in the phosphor material, in which the CNTs act as convenient channels for electrons to be removed in cathodoluminescence. By introducing a small amount of CNTs into the phosphor, the saturation behavior in low voltage cathodoluminescence is effectively restrained, which has a similar effect as improving the conductivity of the phosphor material. The field enhancement effect in the CNT-introduced phosphor material may be activated and become more effective when the applied current density in cathodoluminescence is increased, thus the dynamic performance of the CNT-introduced phosphor material is favorable in low voltage cathodoluminescence.

16.
Phys Chem Chem Phys ; 17(15): 9936-41, 2015 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-25781075

RESUMO

With the increase of applied current density in low voltage cathodoluminescence, the exciting power tends to saturate, causing the saturation of electron-hole generation rate in the phosphor layer. Moreover, ground-state depletion could emerge for the activators owing to the increased exciting power and decreased average penetration depth of incident electrons in the phosphor layer, causing the decrease of the energy transfer probability of e-h pairs exciting ground-state activators. In addition, the radiative transition probability of excited activators could be decreased due to the increase of temperature. In view of these key factors, the efficiency decrease in cathodoluminescence is the inevitable result. To restrain the efficiency decrease so as to improve the performance in low voltage cathodoluminescence, the conductivity of the phosphor material was improved. By introducing a conductive component, which improves the conductivity of the phosphor material, the performance in low voltage cathodoluminescence was effectively improved.

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