Stress, Vascular Smooth Muscle Cell Phenotype and Atherosclerosis: Novel Insight into Smooth Muscle Cell Phenotypic Transition in Atherosclerosis.

PURPOSE OF REVIEW: Our work is to establish more distinct association between specific stress and vascular smooth muscle cells (VSMCs) phenotypes to alleviate atherosclerotic plaque burden and delay atherosclerosis (AS) progression. RECENT FINDING: In recent years, VSMCs phenotypic transition has received significant interests. Different stresses were found to be associated with VSMCs phenotypic transition. However, the explicit correlation between VSMCs phenotype and specific stress has not been elucidated clearly yet. We discover that VSMCs phenotypic transition, which is widely involved in the progression of AS, is associated with specific stress. We discuss approaches targeting stresses to intervene VSMCs phenotypic transition, which may contribute to develop innovative therapies for AS.

Levosimendan: A New Therapeutical Strategy in Patients with Renal Insufficiency.

Levosimendan, a Ca2 + sensitizer with positive inotropic effects, is primarily employed for the short-term treatment of acute decompensated heart failure (ADHF). Levosimendan exerts renal function protection through various mechanisms, including anti-apoptosis, anti-inflammatory, and antioxidant effects in vivo. Additionally, levosimendan may have a protective effect on individuals with heart failure and renal insufficiency, as well as on renal function impairment after cardiac surgery. However, the application of levosimendan in patients with severe renal dysfunction remains controversial. This article delves into the use of levosimendan in severe renal insufficiency, explores its impact on renal function, and provides a comprehensive overview of its impact on renal function after cardiac surgery.

Persistence of severe global inequalities in the burden of Hypertension Heart Disease from 1990 to 2019: findings from the global burden of disease study 2019.

AIMS: Assessing the global burden and health inequalities of Hypertension Heart Disease (HHD) during the period from 1990 to 2019. METHODS: Secondary analysis of the Global Burden of Disease (GBD) study in 2019, focusing on the burden of diseases, injuries, and risk factors worldwide. Disability-Adjusted Life Years (DALYs) data related to HHD are extracted from the 2019 GBD. Inequality Slope Index (SII) and Concentration Index are calculated to assess health inequalities across regions and countries. RESULTS: The total DALYs for HHD reached 21.51 million, demonstrating a substantial increase of 54.25% compared to the figures recorded in 1990, while the age-standardized DALY rates per 100,000 population for HHD in 2019 showed a notable decline to 268.19 (95% UI 204.57, 298.07), reflecting a significant decrease of 26.4% compared to the rates observed in 1990. The DALYs rate of hypertensive heart disease increases with age. Countries with moderate SDI accounted for 38.72% of the global burden of HHD in terms of DALYs. The highest age-standardized DALY rates (per 100,000) are predominantly concentrated in underdeveloped areas. In 1990 and 2019, the SII (per 100,000 population) for DALYs were - 121.6398 (95% CI -187.3729 to -55.90684) and - 1.592634 (95% CI -53.11027 to 49.925) respectively. The significant decline suggests a reduction in the inequality of age-standardized burden of HHD between high-income and low-income countries during this period. CONCLUSION: The unequal prevalence of HHD across different populations can hinder the achievement of the "health for all" objective. Persistent disparities in HHD have been observed globally over the past thirty years. It is crucial to prioritize efforts towards reducing avoidable health inequalities associated with hypertension-related heart disease, particularly in low-income and middle-income countries.

Notoginsenoside R1 decreases intraplaque neovascularization by governing pericyte-endothelial cell communication via Ang1/Tie2 axis in atherosclerosis.

Atherosclerosis represents the major cause of mortality worldwide and triggers higher risk of acute cardiovascular events. Pericytes-endothelial cells (ECs) communication is orchestrated by ligand-receptor interaction generating a microenvironment which results in intraplaque neovascularization, that is closely associated with atherosclerotic plaque instability. Notoginsenoside R1 (R1) exhibits anti-atherosclerotic bioactivity, but its effect on angiogenesis in atherosclerotic plaque remains elusive. The aim of our study is to explore the therapeutic effect of R1 on vulnerable plaque and investigate its potential mechanism against intraplaque neovascularization. The impacts of R1 on plaque stability and intraplaque neovascularization were assessed in ApoE-/- mice induced by high-fat diet. Pericytes-ECs direct or non-direct contact co-cultured with VEGF-A stimulation were used as the in vitro angiogenesis models. Overexpressing Ang1 in pericytes was performed to investigate the underlying mechanism. In vivo experiments, R1 treatment reversed atherosclerotic plaque vulnerability and decreased the presence of neovessels in ApoE-/- mice. Additionally, R1 reduced the expression of Ang1 in pericytes. In vitro experiments demonstrated that R1 suppressed pro-angiogenic behavior of ECs induced by pericytes cultured with VEGF-A. Mechanistic studies revealed that the anti-angiogenic effect of R1 was dependent on the inhibition of Ang1 and Tie2 expression, as the effects were partially reversed after Ang1 overexpressing in pericytes. Our study demonstrated that R1 treatment inhibited intraplaque neovascularization by governing pericyte-EC association via suppressing Ang1-Tie2/PI3K-AKT paracrine signaling pathway. R1 represents a novel therapeutic strategy for atherosclerotic vulnerable plaques in clinical application.

Association between estimated pulse wave velocity and in-hospital and one-year mortality of patients with chronic kidney disease and atherosclerotic heart disease: a retrospective cohort analysis of the MIMIC-IV database.

BACKGROUND: Carotid-femoral pulse wave velocity has been identified as an autonomous predictor of cardiovascular mortality and kidney injury. This important clinical parameter can be non-invasively estimated using the calculated pulse wave velocity (ePWV). The objective of this study was to examine the correlation between ePWV and in-hospital as well as one-year mortality among critically ill patients with chronic kidney disease (CKD) and atherosclerotic heart disease (ASHD). METHODS: This study included a cohort of 1173 patients diagnosed with both CKD and ASHD, sourced from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. The four groups divided into quartiles according to ePWV were compared using a Kaplan-Meier survival curve to assess variations in survival rates. Cox proportional hazards models were employed to analyze the correlation between ePWV and in-hospital as well as one-year mortality among critically ill patients with both CKD and ASHD. To further investigate the dose-response relationship, a restricted cubic splines (RCS) model was utilized. Additionally, stratification analyses were performed to examine the impact of ePWV on hospital and one-year mortality across different subgroups. RESULTS: The survival analysis results revealed a negative correlation between higher ePWV and survival rate. After adjusting for confounding factors, higher ePWV level (ePWV > 11.90 m/s) exhibited a statistically significant association with an increased risk of both in-hospital and one-year mortality among patients diagnosed with both CKD and ASHD (HR = 4.72, 95% CI = 3.01-7.39, p < 0.001; HR = 2.04, 95% CI = 1.31-3.19, p = 0.002). The analysis incorporating an RCS model confirmed a linear escalation in the risk of both in-hospital and one-year mortality with rising ePWV values (P for nonlinearity = 0.619; P for nonlinearity = 0.267). CONCLUSIONS: The ePWV may be a potential marker for the in-hospital and one-year mortality assessment of CKD with ASHD, and elevated ePWV was strongly correlated with an elevated mortality risk in patients diagnosed with both CKD and ASHD.

Association between estimated pulse wave velocity and in-hospital mortality of patients with acute kidney injury: a retrospective cohort analysis of the MIMIC-IV database.

BACKGROUND: Estimated pulse wave velocity (ePWV) has been found to be an independent predictor of cardiovascular mortality and kidney injury, which can be estimated noninvasively. This study aimed to investigate the association between ePWV and in-hospital mortality in critically ill patients with acute kidney injury (AKI). METHODS: This study included 5960 patients with AKI from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. The low and high ePWV groups were compared using a Kaplan-Meier survival curve to evaluate the differences in survival status. Cox proportional hazards models were used to explore the association between ePWV and in-hospital mortality in critically ill patients with AKI. To further examine the dose-response relationship, we used a restricted cubic spline (RCS) model. Stratification analyses were conducted to investigate the effect of ePWV on hospital mortality across various subgroups. RESULTS: Survival analysis indicated that patients with high ePWV had a lower survival rate than those with low ePWV. Following adjustment, high ePWV demonstrated a statistically significant association with an increased risk of in-hospital mortality among AKI patients (HR = 1.53, 95% CI = 1.36-1.71, p < 0.001). Analysis using the RCS model confirmed a linear increase in the risk of hospital mortality as the ePWV values increased (P for nonlinearity = 0.602). CONCLUSIONS: A high ePWV was significantly associated with an increased risk of in-hospital mortality among patients with AKI. Furthermore, ePWV was an independent predictor of in-hospital mortality in critically ill patients with AKI.

Panax Notoginseng Saponins Protect H9c2 Cells From Hypoxia-reoxygenation Injury Through the Forkhead Box O3a Hypoxia-inducible Factor-1 Alpha Cell Signaling Pathway.

ABSTRACT: Panax notoginseng saponins (PNS) are commonly used in the treatment of cardiovascular diseases. Whether PNS can protect myocardial ischemia-reperfusion injury by regulating the forkhead box O3a hypoxia-inducible factor-1 alpha (FOXO3a/HIF-1α) cell signaling pathway remains unclear. The purpose of this study was to investigate the protective effect of PNS on H9c2 cardiomyocytes through the FOXO3a/HIF-1α cell signaling pathway. Hypoxia and reoxygenation of H9C2 cells were used to mimic MIRI in vitro, and the cells were treated with PNS, 2-methoxyestradiol (2ME2), and LY294002." Cell proliferation, lactate dehydrogenase, and malonaldehyde were used to evaluate the degree of cell injury. The level of reactive oxygen species was detected with a fluorescence microscope. The apoptosis rate was detected by flow cytometry. The expression of autophagy-related proteins and apoptosis-related proteins was detected by western blot assay. PNS could reduce H9c2 hypoxia-reoxygenation injury by promoting autophagy and inhibiting apoptosis through the HIF-1α/FOXO3a cell signaling pathway. Furthermore, the protective effects of PNS were abolished by HIF-1α inhibitor 2ME2 and PI3K/Akt inhibitor LY294002. PNS could reduce H9c2 hypoxia-reoxygenation injury by promoting autophagy and inhibiting apoptosis through the HIF-1α/FOXO3a cell signaling pathway.

Panax Notoginseng Saponins Attenuate Myocardial Ischemia-Reperfusion Injury Through the HIF-1α/BNIP3 Pathway of Autophagy.

BACKGROUND AND OBJECTIVE: Panax Notoginseng Saponins (PNS) is a formula of Chinese medicine commonly used for treating ischemia myocardial in China. However, its mechanism of action is yet unclear. This study investigated the effect and the mechanism of PNS on myocardial ischemia-reperfusion injury (MIRI) through the hypoxia-inducible factor 1α (HIF-1α)/bcl-2/adenovirus E1B19kDa-interacting protein3 (BNIP3) pathway of autophagy. METHODS: We constructed a rat model of myocardial injury and compared among 4 groups (n = 10, each): the sham-operated group (Sham), the ischemia-reperfusion group (IR), the PNS low-dose group, and the PNS high-dose group were pretreated with PNS (30 and 60 mg/kg, respectively). Serum creatine kinase, malonaldehyde (MDA), lactate dehydrogenase, myocardial tissue superoxide dismutase, and reactive oxygen species were detected in rats with myocardial ischemia-reperfusion after the intervention of PNS. The rat myocardial tissue was examined using hematoxylin and eosin (H&E) staining, and the mitochondria of myocardial cells were observed using transmission electron microscopy. The expressions of microtubule-associated protein light chain 3 (LC3), HIF-1α, BNIP3, Beclin-1, and autophagy-related gene-5 (Atg5) in rat myocardial tissue were detected using Western blotting. RESULTS: The results showed that PNS was significantly protected against MIRI, as evidenced by the decreasing in the concentration of serum CK, MDA, lactate dehydrogenase, and myocardial tissue superoxide dismutase, reactive oxygen species, the attenuation of myocardial tissue histopathological changes and the mitochondrial damages of myocardial cells, and the increase of mitochondria autophagosome in myocardial cells. In addition, PNS significantly increased the expression of LC3 and the ratio of LC3II/LC3I in rat myocardial tissue. Moreover, PNS significantly increased the expression of HIF-1α, BNIP3, Atg5, and Beclin-1 in rat myocardial tissue. CONCLUSIONS: The protective effect of PNS on MIRI was mainly due to its ability to enhance the mitochondrial autophagy of myocardial tissue through the HIF-1α/BNIP3 pathway.

Photoluminescence properties of aeschynite-type LaNbTiO6:RE3+ (RE = Tb, Dy, Ho) down-converting phosphors.

In this study, a series of LaNbTiO6:RE(3+) (RE = Tb, Dy, Ho) down-converting phosphors were synthesized using a modified sol-gel combustion method, and their photoluminescence (PL) properties were investigated as a function of activator concentration and annealing temperature. The resultant particles were characterized using X-ray diffraction, transmission electron microscopy, scanning electron microscopy, UV/Vis diffuse reflectance spectroscopy and PL spectra. The highly crystalline LaNbTiO6:RE(3+) (RE = Tb, Dy, Ho) phosphors with an average size of 200-300 nm obtained at 1100°C have an orthorhombic aeschynite-type structure and exhibit the highest luminescent intensity in our study range. The emission spectra of LaNbTiO6:RE(3+) (RE = Tb, Dy, Ho) phosphors under excitations at UV/blue sources are mainly composed of characteristic peaks arising from the f-f transitions of RE(3+), including 489 nm ((5) D4 → (7) F6) and 545 nm ((5) D4 → (7) F5) for Tb(3+), 476 and 482 nm ((4) F9/2 → (6) H15/2) and 571 nm ((4) F9/2 → (6) H13/2) for Dy(3+), and 545 nm ((5) F4 + (5) S2 → (5) I8) for Ho(3+), respectively. The luminescent mechanisms were further investigated. It can be expected that these phosphors are of intense interest and potential importance for many optical applications.

Three-Dimensional Thermo-Chemo-Mechanical Coupled Curing Analysis for the Filament Wound Composite Shell.

Carbon fiber resin-based composite materials are widely employed in the manufacturing of composite shells. During the curing process, the temperature gradients and cure degree gradients make it easy to generate thermal strains in both carbon fibers and resin, with the resin experiencing cure shrinkage strain due to the curing reaction, ultimately leading to residual stresses and strains. In this paper, a three-dimensional thermo-chemo-mechanical coupled curing model of the composite shell was established based on a resin test, and the changes of temperature, curing degree, residual stress, and strain during the solidification of the composite shell were investigated. First, the curing property parameters and elastic modulus of HCM-2184 resin were obtained through a curing dynamic test and a tensile test. Then, considering the heat release and shrinkage reaction of solidification, a coupled thermo-chemo-mechanical curing model was developed with the CHILE (α) elastic model, and the curing process of the composite shell was simulated numerically. The results show that the resin used in the test belongs to the autocatalytic reaction. For thin composite shells, the heat accumulation inside the shell during curing is not obvious. During the curing process, the curing shrinkage behavior of the resin is an important factor for the generation of residual stress and residual strain.

Advances in the study of vascular related protective effect of garlic (Allium sativum) extract and compounds.

Garlic (Allium sativum) is a functional food containing multiple bioactive compounds that find widespread applications in culinary and medicinal practices. It consists of multiple chemical components, including allicin and alliin. This article offers a comprehensive review of the protective effects of garlic extracts and their active constituents on the vascular system. In vitro and in vivo experiments have shown that garlic extracts and their active ingredients possess various bioactive properties. These substances demonstrate beneficial effects on blood vessels by demonstrating anti-inflammatory and antioxidant activities, inhibiting lipid accumulation and migration, preventing lipid peroxidation, promoting angiogenesis, reducing platelet aggregation, enhancing endothelial function, and inhibiting endothelial cell apoptosis. In clinical studies, garlic and its extracts have demonstrated their efficacy in managing vascular system diseases, including atherosclerosis, diabetes, and high cholesterol levels. In summary, these studies highlight the potential therapeutic roles and underlying mechanisms of garlic and its constituents in managing conditions like diabetes, atherosclerosis, ischemic diseases, and other vascular disorders.

Hypoxia-inducible factor-1: Regulatory mechanisms and drug therapy in myocardial infarction.

Myocardial infarction (MI), an acute cardiovascular disease characterized by coronary artery blockage, inadequate blood supply, and subsequent ischemic necrosis of the myocardium, is one of the leading causes of death. The cellular, physiological, and pathological responses following MI are complex, involving multiple intertwined pathological mechanisms. Hypoxia-inducible factor-1 (HIF-1), a crucial regulator of hypoxia, plays a significant role in of the development of MI by modulating the behavior of various cells such as cardiomyocytes, endothelial cells, macrophages, and fibroblasts under hypoxic conditions. HIF-1 regulates various post-MI adaptive reactions to acute ischemia and hypoxia through various mechanisms. These mechanisms include angiogenesis, energy metabolism, oxidative stress, inflammatory response, and ventricular remodeling. With its crucial role in MI, HIF-1 is expected to significantly influence the treatment of MI. However, the drugs available for the treatment of MI targeting HIF-1 are currently limited, and most contain natural compounds. The development of precision-targeted drugs modulating HIF-1 has therapeutic potential for advancing MI treatment research and development. This study aimed to summarize the regulatory role of HIF-1 in the pathological responses of various cells following MI, the diverse mechanisms of action of HIF-1 in MI, and the potential drugs targeting HIF-1 for treating MI, thus providing the theoretical foundations for potential clinical therapeutic targets.

Identification of Circulating Plasma Proteins as a Mediator of Hypertension-Driven Cardiac Remodeling: A Mediation Mendelian Randomization Study.

BACKGROUND: This study focused on circulating plasma protein profiles to identify mediators of hypertension-driven myocardial remodeling and heart failure. METHODS: A Mendelian randomization design was used to investigate the causal impact of systolic blood pressure (SBP), diastolic blood pressure (DBP), and pulse pressure on 82 cardiac magnetic resonance traits and heart failure risk. Mediation analyses were also conducted to identify potential plasma proteins mediating these effects. RESULTS: Genetically proxied higher SBP, DBP, and pulse pressure were causally associated with increased left ventricular myocardial mass and alterations in global myocardial wall thickness at end diastole. Elevated SBP and DBP were linked to increased regional myocardial radial strain of the left ventricle (basal anterior, mid, and apical walls), while higher SBP was associated with reduced circumferential strain in specific left ventricular segments (apical, mid-anteroseptal, mid-inferoseptal, and mid-inferolateral walls). Specific plasma proteins mediated the impact of blood pressure on cardiac remodeling, with FGF5 (fibroblast growth factor 5) contributing 2.96% (P=0.024) and 4.15% (P=0.046) to the total effect of SBP and DBP on myocardial wall thickness at end diastole in the apical anterior segment and leptin explaining 15.21% (P=0.042) and 23.24% (P=0.022) of the total effect of SBP and DBP on radial strain in the mid-anteroseptal segment. Additionally, FGF5 was the only mediator, explaining 4.19% (P=0.013) and 4.54% (P=0.032) of the total effect of SBP and DBP on heart failure susceptibility. CONCLUSIONS: This mediation Mendelian randomization study provides evidence supporting specific circulating plasma proteins as mediators of hypertension-driven cardiac remodeling and heart failure.

Normal saline: Past, present, and future.

Normal saline (NS) is the most widely used agent in the medical field. However, from its origin to its widespread application, it remains a mystery. Moreover, there is an ongoing debate on whether its existence is reasonable, harmful to the human body, or will still exist in the future. The current review traces back to the origins of NS and provides a brief overview of the current situation of infusion. The purpose may shed some light on the possibility of the existence of NS in the future by elaborating on the origin of NS and the research status of the impact of NS on the human body.

Effect of Astragaloside IV on improving cardiac function in rats with heart failure: a preclinical systematic review and meta-analysis.

Background: Astragaloside IV (ASIV) is the primary pharmacologically active compound found in Astragalus propinquus Schischkin, which has potential protective effects on cardiac function. However, there are almost no systematic evaluations of ASIV for the treatment of heart failure (HF). Methods: Preclinical studies published before 27 December 2022, were retrieved from PubMed, Web of Science, MEDLINE, SinoMed, Chinese National Knowledge Infrastructure (CNKI), VIP information database, and Wanfang Data information site. The quality of included research was evaluated using SYRCLE's RoB tool. Review Manager 5.4.1 was used to perform meta-analyses of the cardiac function parameters and other indicators. Regression analysis was conducted to observe the dose-efficacy relationship. Results: Nineteen studies involving 489 animals were included. Results indicated that compared with the control group, ASIV could enhance cardiac function indicators, including left ventricular ejection fraction (LVEF), left ventricular fractional shortening (LVFS), left ventricular pressure change rate (±dp/dtmax), left ventricular end-diastolic pressure (LVEDP), left ventricular systolic pressure (LVSP), heart weight/body weight (HW/BW) and left ventricular weight/body weight (LVW/BW). Furthermore, the regression analysis showed that the treatment of HF with ASIV was dose-dependent. Conclusion: Findings suggest that ASIV can inhibit cardiac hypertrophy by reducing cardiac preload and afterload, thereby protecting cardiac function.

Advances in the study of the vascular protective effects and molecular mechanisms of hawthorn (Crataegus anamesa Sarg.) extracts in cardiovascular diseases.

Hawthorn belongs to the rose family and is a type of functional food. It contains various chemicals, including flavonoids, terpenoids, and organic acid compounds. This study aimed to review the vascular protective effects and molecular mechanisms of hawthorn and its extracts on cardiovascular diseases (CVDs). Hawthorn has a wide range of biological functions. Evidence suggests that the active components of HE reduce oxidative stress and inflammation, regulate lipid levels to prevent lipid accumulation, and inhibit free cholesterol accumulation in macrophages and foam cell formation. Additionally, hawthorn extract (HE) can protect vascular endothelial function, regulate endothelial dysfunction, and promote vascular endothelial relaxation. It has also been reported that the effective components of hawthorn can prevent age-related endothelial dysfunction, increase cellular calcium levels, cause antiplatelet aggregation, and promote antithrombosis. In clinical trials, HE has been proved to reduce the adverse effects of CVDs on blood lipids, blood pressure, left ventricular ejection fraction, heart rate, and exercise tolerance. Previous studies have pointed to the benefits of hawthorn and its extracts in treating atherosclerosis and other vascular diseases. Therefore, as both medicine and food, hawthorn can be used as a new drug source for treating cardiovascular diseases.

Interfacial confined formation of mesoporous spherical TiO2 nanostructures with improved photoelectric conversion efficiency.

Uniform mesoporous TiO(2) nanospheres were successfully developed via an interfacial confined formation process for application in dye-sensitized solar cells. The mesoporous spherical structures greatly promote the dye-loading capacity, electron transfer, and light scattering, resulting in remarkable enhancement of the cell performance. The designed interfacial platform caused a reaction-limited aggregation of the TiO(2) nanocrystals, resulting in the formation of mesoporous spherical nanostructures with sphere diameter of 216 nm and pore size of 8 nm. The oriented attachment of adjacent TiO(2) nanocrystals facilitated the electron transfer process when the mesoporous TiO(2) nanospheres were used as electrode films. The dye coverage was enhanced remarkably in the mesoporous spherical TiO(2) samples. Owing to the enhanced light-harvesting efficiency, solar conversion efficiency was enhanced about 30% for the dye-sensitized solar cell (DSSC) based on mesoporous spherical TiO(2) in comparison with that made by commercial TiO(2) nanoparticles.

Synthesis of anatase TiO(2) nanoshuttles by self-sacrificing of titanate nanowires.

Anatase TiO(2) nanoshuttles have been successfully prepared via a hydrothermal method under alkaline conditions by employing titanate nanowires as the self-sacrificing precursors. The experimental results showed that a radical structural rearrangement took place from titanate wires to anatase TiO(2) shuttles during the hydrothermal reaction on the basis of a dissolution-recrystallization process. The surface of titanate nanowires plays a key role in the transformation process by providing both the structural units (e.g., TiO(6) octahedra) to realize anatase transformation and locations for the deposition and rearrangement of the dissolved structural units, while the formation of shuttle morphology is attributed to the minimization of surface energy with thermodynamically stable (101) facets of anatase TiO(2). The shape and phase transformation process were foundto be dependent on the hydrothermal reaction time. Raman and photoluminescence spectra confirmed the crystalline nature of the TiO(2) nanoshuttles.

Novel class of aeschynite structure LaNbTiO6-based orange-red phosphors via a modified combustion approach.

A novel class of orange-red phosphors based on Eu(3+)-activated LaNbTiO(6) was successfully fabricated by a wet chemical method, called a modified combustion approach. XRD, TG-DTA, SEM, and EDS results show that the heat-treatment of the powders above 1000 degrees C is enough to obtain highly crystallized and phase-pure LaNbTiO(6) and Eu(3+)-doped samples, which is of prime importance in investigating the optical properties of the novel phosphors using LaNbTiO(6) as the host material. UV-vis diffuse reflectance spectroscopy reveals that the direct band gap of LaNbTiO(6) with large grains (above 200 nm) is calculated to be 3.27 eV, while the absorption edge of the small particles shows an obvious blue-shift. Two blue emission bands centered at 440 and 470 nm ascribed to the self-trapped exciton emission of the distorted NbO(6) and TiO(6) groups for the pure LaNbTiO(6) can be obtained. Photoluminescence spectra of the Eu(3+)-doped phosphor particles illuminated the simultaneous occurrence of several intense orange-red band emissions due to the characteristic transitions of (5)D(0,1) --> (7)F(J) (J = 0, 1, 2, 3, 4) of Eu(3+) under 395 nm excitation. The mechanism of these multiplets possibly arising from the odd-parity distortions of the Eu(3+) ion environment and the effect of crystallanity of the compounds on luminescence were discussed, respectively. The highly bright and color-uniform fluorescence images of the doped samples with short luminescence decay times (nanosecond magnitude) confirmed the potential applications of the phosphors in luminescence and display devices.

Combustion synthesis of novel Li 0.9 Y(0.9-x-y)Zr 0.1 O2:Eu x 3+, R y 3+(R = Ce,Bi) red luminescence nanocrystal and emission-mechanism research.

Novel Li(0.9)Y((0.9-x-y))Zr(0.1)O(2):Eu(x)(3+), R(y)(3+) (R = Ce,Bi) red nanocrystal phosphors were synthesized by the sol-combustion process at 800 degrees C. XRD and TEM were used to evaluate the crystallinity and the morphological characterization of the samples. The photoluminescence properties and lifetime of the obtained phosphor nanoparticles were measured using an Edinburgh FLS920 at room temperature. The result showed that the luminescence intensity of Li(0.9)Y((0.9-x-y))Zr(0.1)O(2):Eu(x)(3+) was increased by Bi(3+) and Ce(3+) by 900% and 600%, respectively. The emission mechanism and sensitization mechanism of Bi(3+) and Ce(3+) on Eu(3+) emission intensity were described and explained in detail in this work. The high bright and color-uniform fluorescence images of the doped samples with short luminescence decay times (nanosecond level) confirmed the potential applications of the phosphors in light-emitting diodes and display devices.