Predictive and prognostic impact of the different features of tumor budding in stage II colorectal cancer.

Tumor budding is a significant independent prognostic factor in colorectal cancer. Routine reporting of tumor budding is now advocated for in the colorectal cancer standard approach recommended by the International Tumor Budding Consensus Conference guidelines. However, the current tumor budding assessment system only emphasizes tumor budding quantity and ignores other features. Therefore, this study aimed to further determine the prognostic value of tumor budding based on a more comprehensive feature analysis. To this end, we conducted a retrospective pathology review of the different characteristics of tumor budding (that is quantity, structure, cell atypia, location, stromal reaction, and immunohistochemical phenotype) in 224 specimens of stage II colorectal cancer at our institution between 2009 and 2015. The mean age of the patients was 60.3±9.2 years (range, 39-84 years). Among various features of tumor budding, single-cell budding, anaplasia-like cell atypia, myxoid stroma, high tumor budding quantity, and loss of CDX2 expression were independent predictors of recurrence and mortality in patients with stage II colorectal cancer. Based on these results, we suggest that in addition to tumor-budding quantity, other tumor budding features play important biological roles in the development of colorectal cancer. Our findings provide prognostic information that could help with guiding clinical management and oncology care models for patients with stage II colorectal cancer.

IL33 activates CD8+T and NK cells through MyD88 pathway to suppress the lung cancer cell growth in mice.

OBJECTIVE: In this study, we observed the effects of IL-33 on tumor immune response in lung cancer-bearing mice using wild type and MyD88-/- mice respectively. METHODS: Wild C57BL/6 (C57BL/6WT), MyD88 knockout C57BL/6 mice (C57BL/6 MyD88-/-) and Lewis cells were used in this study. Cell proliferation, cytokine release and cytotoxicity were detected. RESULTS: IL-33 could significantly up-regulate specific cellular immunity, inhibit tumor growth and improve survival time in wild type mice group, and it had dose dependent effect. However, IL-33 had no effect on cell immunity and tumor growth in MyD88-/- mice group. Compared with MyD88-/- mice, IL-33 could significantly increase the ratio of CD8+T cells to neutrophils in wild type mice, while the percentage of tumor infiltrating CD11b+ cells, Mo-MDSC, F4/80+ macrophages and mDC cells decreased significantly in wild type mice group. IL-33 could upregulate the expression of CD107a and IFN-γ in CD8+T cells and NK cells of wild type mice, while IL-33 could not upregulate them in MyD88-/- mice. IL-33 could upregulate the expression of CD40, CD80, CD86 and CD205 in DC cells in wild type mice, induce T cells to differentiate into Th1 cells and enhance tumor cell immunity. CONCLUSIONS: IL-33 could promote differentiation and maturation of DC cells through MyD88 pathway, up-regulate the tumor immunity of CD8+T cells and NK cells, and inhibit the proliferation of lung cancer cells.

Plant-soil-foliage feedbacks on seed germination and seedling growth of the invasive plant Ageratina adenophora.

Some exotic plants become invasive because they partially release from soil-borne enemies and thus benefit from positive plant-soil feedbacks (PSFs) in the introduced range. However, reports that have focused only on PSFs may exaggerate the invader's competitiveness. Here, we conducted three experiments to characterize plant-soil-foliage feedbacks, including mature leaves (ML), leaf litter (LL), rhizosphere soil (RS) and leaves plus soil (LS), on the early growth stages of the invasive plant Ageratina adenophora. In general, the feedbacks from aboveground (ML, LL) adversely affected A. adenophora by delaying germination time, inhibiting germination rate and reducing seedling growth. The increased invasion history exacerbated the adverse effects of LL and LS feedbacks on seedling growth. These adverse effects were partially contributed by more abundant fungi (e.g. Didymella) or/and more virulent fungi (e.g. Fusarium) developed in the aboveground part of A. adenophora during the invasion. Interestingly, the aboveground adverse effects can be weakened by microbes from RSs. Our novel findings emphasize the important role of aboveground feedbacks in the evaluation of plant invasiveness, and their commonness and significance remain to be explored in other invasive systems.

IL-1ß promotes malignant transformation and tumor aggressiveness in oral cancer.

Chronic inflammation, coupled with alcohol, betel quid, and cigarette consumption, is associated with oral squamous cell carcinoma (OSCC). Interleukin-1 beta (IL-1ß) is a critical mediator of chronic inflammation and implicated in many cancers. In this study, we showed that increased pro-IL-1ß expression was associated with the severity of oral malignant transformation in a mouse OSCC model induced by 4-Nitroquinolin-1-oxide (4-NQO) and arecoline, two carcinogens related to tobacco and betel quid, respectively. Using microarray and quantitative PCR assay, we showed that pro-IL-1ß was upregulated in human OSCC tumors associated with tobacco and betel quid consumption. In a human OSCC cell line TW2.6, we demonstrated nicotine-derived nitrosamine ketone (NNK) and arecoline stimulated IL-1ß secretion in an inflammasome-dependent manner. IL-1ß treatment significantly increased the proliferation and dysregulated the Akt signaling pathways of dysplastic oral keratinocytes (DOKs). Using cytokine antibodies and inflammation cytometric bead arrays, we found that DOK and OSCC cells secreted high levels of IL-6, IL-8, and growth-regulated oncogene-α following IL-1ß stimulation. The conditioned medium of IL-1ß-treated OSCC cells exerted significant proangiogenic effects. Crucially, IL-1ß increased the invasiveness of OSCC cells through the epithelial-mesenchymal transition (EMT), characterized by downregulation of E-cadherin, upregulation of Snail, Slug, and Vimentin, and alterations in morphology. These findings provide novel insights into the mechanism underlying OSCC tumorigenesis. Our study suggested that IL-1ß can be induced by tobacco and betel quid-related carcinogens, and participates in the early and late stages of oral carcinogenesis by increasing the proliferation of dysplasia oral cells, stimulating oncogenic cytokines, and promoting aggressiveness of OSCC.

Effects of melatonin combined with Cis-platinum or methotrexate on the proliferation of osteosarcoma cell line SaOS-2.

OBJECTIVE: To evaluate the effects of melatonin (Mel) combined with cis-platinum (DDP) or methotrexate (MTX) on the proliferation of osteosarcoma cell line SaOS-2, and to explore whether Mel combined with DDP or MTX could play a synergistic antitumor effect. METHODS: SaOS-2 was treated with Mel alone or Mel combined with DDP or MTX. Cell counting kit-8 assay was used to measure the cell activities. Combination index(CI) value was used to evaluate the combined effects: CI<1 indicating synergetic effect, CI=1 additive, and CI>1 antagonistic.Flow cytometry was used to analyze cell cycle distribution and cell apoptosis. RESULTS: After treated with Mel (0.5,1,2,4,5 mmol/L), DDP (6.67, 16.67, 33.33, 66.66 µmol/L) or MTX(0.1, 0.5, 1, 2, 4 mmol/L)alone,SaOS-2 cell activities decreased in a dose-dependent manner (all P<0.05). The activities of SaOS-2 cell treated with both Mel (1 mmol/L) and DDP or MTX were significantly lower than that of DDP or MTX alone (all P<0.05).CI values of cells exposed to 1 mmol/L Mel plus 6.67, 16.67, 33.33, and 66.66 µmol/L DDP were 1.18, 1.21, 1.09, and 0.84, respectively,and CI values of cells exposed to 1 mmol/L Mel plus 0.1, 0.5, 1, 2, and 4 mmol/L MTX were 0.88, 0.88 ,0.83, 0.78, and 0.81, respectively. The G1-stage cells were increased and the S-stage cells were reduced when the cells were treated with Mel (1 mmol/L) alone or combined with MTX (0.5 mmol/L) (P<0.05). The S-stage cells were increased when the cells treated with MTX (0.5 mmol/L) (P<0.05). The apoptotic cells were increased when they treated with Mel (1 mmol/L) alone or combined with DDP (16.67 µmol/L) or MTX (0.5 mmol/L) (P<0.05). When the cells were treated with Mel combined with DDP or MTX, the apoptotic cells were more than that of DDP or Mel alone(P<0.05). CONCLUSIONS: Mel can inhibit SaOS-2 cells activity,block the cell cycle at G1-stage,and induce apoptosis. Mel has an antagonistic effect with lower concentration of DDP but a synergistic effect with MTX or higher concentration of DDP.

Prevention of contamination by biopsy needle track contamination using a novel adriamycin-loaded gelatin sponge.

BACKGROUND: The gold standard of tumor diagnosis is histological examination of a biopsy; however, there is concern that tumor cell dissemination along the needle track during percutaneous biopsy can cause local tumor relapse. We aimed to evaluate the value of an adriamycin (ADM)-loaded gelatin sponge in preventing tumor cell contamination along the biopsy needle track. METHODS: Data were obtained from 40 patients who were diagnosed by core needle biopsy as having osteosarcoma and who were followed up at our hospital between 2008 and 2011. Of the 40 patients, 20 had the needle biopsy tracks filled with ADM-loaded absorbable gelatin sponge immediately after the biopsy specimen was obtained, while the other 20 did not. All 40 patients underwent limb-salvage surgery, and specimens were obtained from the biopsy track for histopathologic examination of multiple sections. RESULTS: On histological examination, there was less tumor cell contamination along the biopsy tracks in the ADM group. CONCLUSION: Use of ADM-loaded absorbable gelatin sponge may prevent tumor cell contamination of a biopsy track, and reduce the possibility of consequent tumor relapse.

[Treatment of thoracolumbar tumors with total en bloc spondylectomy and the results of spinal stability reconstruction].

OBJECTIVE: To investigate the therapeutic effect of total en bloc spondylectomy (TES) for thoracolumbar tumors and the results of spinal stability reconstruction. METHODS: From January 2007 to June 2011 there were 18 patients with thoracolumbar tumors distributed in the thoracic vertebrae (n = 10) and lumbar vertebrae (n = 8). There were 7 haemangiomas, 5 giant cell tumors of bone, 1 malignant schwannoma, 1 solitary plasmocytoma, 1 neuroblastoma, 1 osteoblastoma, 1 metastatic malignant fibrous histiocytoma, and 1 metastasis of breast cancer. All the 18 patients were treated with improved TES under electrophysiological monitoring of spinal cord. Four patients were treated through one-stage combined anteroposterior approach and 14 patients through one-stage posterior approach. The anterior reconstructions included titanium mesh cages filled with bone or bone cement in 15 cases, titanium mesh cage with strengthened rings in 2 cases and artificial vertebral body replacement in 1 case. The posterior reconstruction included multiple segmental fixation with pedicle screw-rod system in 15 cases and short segmental fixation in 3 cases. Massive bone auto-graft was employed in 13 cases and fragmental bone graft in 5 cases. RESULTS: The total en bloc spondylectomy was performed successfully in 15 patients and unsuccessful in 3 whose spinal tumors were resected by piecemeal technique. In 15 patients with successfully performed TES, the duration of surgery was from 340 to 610 min (average, 450.7 min), the blood loss was from 3000 to 10 200 ml (average, 4850 ml), and the intraoperative blood transfusion was from 2800 to 9600 ml (average, 4200 ml). The operation-related complications comprised hemopneumothorax, intercostal nerve pain, stress ulcer and bleeding, and so on. One year after operation, the patients with neurological dysfunction recovered from grade A to grade D in one patient, and to grade E in the other 14 cases. The average visual analog scale (VAS) scores was 0.5. One patient with plasmacytoma and another one with L5 metastatic tumor suffered progression of the disease and were living with the diseases. The patient with metastatic malignant fibrous histiocytoma died of local recurrence and lung metastasis 16 months postoperatively. One patient with L4 neuroblastoma died of other reason and all the rest were free from relapse. The Cobb angle of upper and lower vertebral body adjacent to the involved vertebrae in sagittal plane was from -26.7° to 12.0° (average, -2.57°) just postoperatively and from -17.5° to 57.2° (average, 11.5°) at the last follow-up or before reoperation. There were 2 patients with screw-rod breakdown and 2 patients with internal fixation loosening. The measurement of titanium mesh cage subsided into adjacent vertebral bodies was average 7.5 mm. The revision surgery was performed in 3 patients, through combined anteroposterior approach in 2 and only posterior approach in 1 patient. CONCLUSIONS: TES significantly increases the therapeutic effect of spinal tumors, although accompanied with high difficulty and massive bleeding. In spinal stability reconstruction after total spondylectomy, it should be emphasized that posterior long segment fixation with pedicle screw-rod system, massive bone bridging graft and the application of thoracolumbosacral orthosis can achieve short-term firm fixation and long-term fusion-stabilization.

[Spectral characteristics of Ba3SiO4Cl2 : Eu2+ phosphor for white LED].

Ba3SiO4Cl2 : Eu2+ was synthesized by a high temperature solid state method. BaCO3 (A. R.), BaCl2 (A. R.), SiO2 (99.99%) and Eu2O3 (99.99%) were used as the raw materials. The final phase was checked with a conventional X-ray diffraction (XRD) (D/max-rA, CuKalpha, 40 kV, 100 mA, lambda = 0.154 06 nm). The spectral characteristics of the phosphors were performed by using a Hitachi F-4600 fluorescence spectrophotometer equipped with a 450 W Xe lamp. Ba3SiO4Cl2 : Eu2+ showed broad emission bands at 445 and 510 nm under the 365 nm radiation excitation. For the two emission peaks, the excitation spectra have two different spectral distributions, and the excitation peaks locate at 350 and 400 nm, respectively. The results indicate that different Eu2+ emission centres exist in Ba3SiO4Cl2. The emission intensity of the 445 and 510 nm peaks is influenced by Eu2+ doped content. With increasing its content, the emission intensity of 445 nm gradually increases, and that of 510 nm decreases. With washing the phosphor, the 445 nm emission peak disappears, and the emission spectrum has only the 510 nm emission band, and its intensity is lower than that of the original phosphor.

An evaluation of the clinical efficacy of the application of 28mm cryoballoon for linear ablation of left atrial apex combined with enlarged pulmonary vein vestibule ablation for persistent atrial fibrillation.

OBJECTIVE: to retrospectively investigate the efficacy and safety of the application of 28 mm cryoballoon for pulmonary vein electrical isolation (PVI) combined with top left atrial linear ablation and pulmonary vein vestibular expansion ablation for persistent atrial fibrillation. METHODS: From July 2016 to December 2020, 413 patients diagnosed with persistent atrial fibrillation were evaluated, including 230 (55.7%) in the PVI group (PVI only) and 183 (44.3%) in the PVIPLUS group (PVI plus ablation of the left atrial apex and pulmonary vein vestibule). The safety and efficacy of the two groups were retrospectively analyzed. RESULTS: The AF/AT/AFL-free survival rates at 6, 12, 18, 24 and 30 months after procedure was 86.6%, 72.6%, 70.0%, 61.1% and 56.3% in the PVI group and 94.5%, 87.0%, 84.1%, 75.0% and 67.9% in the PVIPLUS group, respectively. At 30 months after procedure, the AF/AT/AFL-free survival rate was significantly higher in the PVIPLUS group than in the PVI group (P = 0.036; HR:0.63; 95% CI:0.42 to 0.95). CONCLUSION: The application of 28-mm cryoballoon for pulmonary vein electrical isolation combined with linear ablation of the left atrial apex and expanded ablation of the pulmonary vein vestibule improves the outcome of persistent atrial fibrillation.

[Preparation and up-conversion luminescence dynamic process of Yb3+/ Er3+ co-doped BaGd2ZnO5].

Yb3+/Er3+ co-doped BaGd2 ZnO5 phosphors were prepared by using the sol-gel method. The up-conversion luminescence powers and efficiencies were measured under different excitation densities. The obtained data showed that the green luminescence power was proportional to the second-order of that of the excitation power under the lower excitation density and linearly in the higher one. The up-conversion mechanism under different excitation power was described by a rate equation. Yb3+/ Er3+ co-doped BaGd2 ZnO5 was excited by 971 nm LD laser with a square wave signal modulation and the rise and decay processes of green up-conversion luminescence were measured. In a low excitation condition, the rate equation of the energy level 4S3/2 for Er3+ ions was used to fit the green rise and decay processes in order to fix the relevant parameters, and confirm that the population of 4S3/2 energy level of Er3+ ion mainly came from the energy transfer from Yb3+ to Er3+.

[Study on the spectral properties of Ca7(SiO4)2Cl6 phosphor for white LED].

A bluish green Ca7 (SiO4)2Cl6 : Eu2+ phosphor used for UV excited white LED was synthesized by high temperature solid state method. The XRD patterns and luminescence properties were investigated. The results indicated that the sample was single Ca7 (SiO4)2Cl6 phase; the emission spectrum included two emission peaks located at 418 and 502 nm, respectively. Monitoring for the two emission peaks, the excitation spectra were two broad band peaks centered at 290 and 360 nm respectively, which illustrated that Eu2+ ions located at two different crystal lattice sites. The influence of Eu2+ ions concentration on the luminescence intensity was studied and the optimal doping concentration was 0.75 mol%. The results showed that this phosphor was a better candidate bluish phosphor for UV based white LED.

Efficacy of extended antrum ablation based on substrate mapping plus pulmonary vein isolation in the treatment of atrial fibrillation.

INTRODUCTION AND OBJECTIVES: Pulmonary vein isolation (PVI) technique has become the cornerstone of atrial fibrillation (AF) catheter ablation. The objective of this study was to assess the efficacy and safety of extended antrum ablation based on electrophysiological substrate mapping plus PVI in AF patients who underwent cryoballoon ablation. METHODS: In this observational study, a total of 121 paroxysmal AF patients and 80 persistent AF patients who did not achieve the procedure endpoint after cryoballoon ablation received extra extended antrum ablation (EAA) based on electrophysiological substrate mapping via radiofrequency ablation (EAA group). As a control group (PVI group), among paroxysmal AF and persistent AF patients, we conducted a propensity score-matched cohort, in whom only PVI was completed. RESULTS: The average follow-up time was 15.27±7.34 months. Compared with PVI group, paroxysmal AF patients in the EAA group had a significantly higher rate of AF-free survival (90.1% vs. 80.2%, p=0.027) and AF, atrial flutter, or atrial tachycardia (AFLAT) -free rate survival (89.3% vs. 79.3%, p=0.031). Persistent AF patients in the EAA group also had a significantly higher rate of AF-free survival (90.0% vs. 75.0%, p=0.016) and AFLAT-free survival (88.8% vs. 75.0%, p=0.029) than PVI group. Complication rates did not significantly differ between both groups, in either paroxysmal AF or persistent AF patients. CONCLUSION: Our findings demonstrate that extra extended antrum ablation based on electrophysiological substrate mapping is effective and safe. Moreover, the strategy can improve the outcome of AF cryoablation.

[Analysis of curative effect for 21 recurrent soft-tissue sarcoma].

OBJECTIVE: To summarize the effect of the surgery for recurrent soft-tissue sarcoma, and evaluate the treatment strategies. METHODS: The curative effect of 21 cases of recurrent soft-tissue sarcomas from January 2005 to March 2011 is analyzed. RESULTS: In 21 cases, 7 cases were amputated, 12 cases were ampliative resection and 2 cases were marginal excision. The 4 cases were recurrent, metastasis and dead, 1 cases were recurrent and live with tumor, 1 cases had metastasis and live with tumor. CONCLUSIONS: Appropriate enough surgery margine can prevent the local recurrence, and complete removal of the tumor and comprehensive radiation and chemotherapy treatment of recurrent soft tissue tumor is the key to success.

[Fabrication and luminescent properties of Dy3+ doped Sr(1-x)Ca(x)MoO4].

Dy3+ doped Sr(1-x)CaxMoO4 phosphors were prepared by solid state method in the present paper. The crystal structure, luminescent properties and the effect of x on the luminescent properties were studied by XRD, SEM, excitation, emission and color parameters. The XRD patterns indicated that the samples were single phase of CaMoO4 and SrMoO4 when x=1 and x=0. It can be seen that the crystal size of samples prepared at 750 degrees C for 3 h were 0.2-1.0 microm, which was matched with solid state luminescent device. The excitation spectra monitored at 576 nm were composed of a broad band at 250-340 nm and a series of narrow band at 340-460 nm. The excitation peaks situation of CT transition and the excitation peaks intensity of narrow bands varied with Sr/Ca. The emission spectra excited by 350 nm were composed of two broad bands at 470 and 576 nm, which were attributed to the transition of 4F(9/2)-->(6)H(15/2) and (4)F(9/2)-->(6)H(13/2). The emission intensity of yellow and blue emission varied with the value of Sr/Ca.

Mortality and Readmission Rates After Heart Failure: A Systematic Review and Meta-Analysis.

OBJECTIVE: The current work aimed to examine the rates of and risk factors for mortality and readmission after heart failure (HF). SETTING: A systematic search was carried out in PubMed, the Cochrane Library, and EMBASE to identify eligible reports. The random-effects model was utilized to evaluate the pooled results. PARTICIPANTS: A total of 27 studies with 515,238 participants were finally meta-analysed. The HF patients had an average age of 76.3 years, with 51% of the sample being male, in the pooled analysis. PRIMARY AND SECONDARY OUTCOME MEASURES: The outcome measures were 30-day and 1-year readmission rates, mortality, and risk factors for readmission and mortality. RESULTS: The effect sizes for readmission and mortality were estimated as the mean and 95% confidence interval (CI). The estimated 30-day and 1-year all-cause readmission rates were 0.19 (95% CI 0.14-0.23) and 0.53 (95% CI 0.46-0.59), respectively, while the all-cause mortality rates were 0.14 (95% CI 0.10-0.18) and 0.29 (95% CI 0.25-0.33), respectively. Comorbidities were highly prevalent in individuals with HF. CONCLUSION: Heart failure hospitalization is followed by high readmission and mortality rates.

[Release kinetics of methotrexate loaded calcium phosphate cement and histological evaluation of the osteogenesis in rabbits].

OBJECTIVE: To observe the release kinetics of methotrexate-loaded calcium phosphate cement (MTX-CPC) implanted in vivo and histologically investigate its resorption and osteogenesis. METHODS: MTX-CPC consisting of 1% methotrexate (MTX) (weight/weight) was pre-set and implanted into femoral muscles of 24 New Zealand rabbits. The in vivo MTX release kinetics was determined on the 1st, 2nd, 5th, 10th, 15th, 20th, 25th, and 30th post-implantation day. The local concentrations and the residual percentage of MTX were determined. Then the pre-set MTX-CPC was implanted into femoral condyle. Calcium phosphate cement (CPC) without MTX was used as a control. The femurs were harvested at the 1st day and the 1st, 3rd, and 6th month and examined by X ray. Then histomorphometric analyses including percentage of newly formed bone and amount of osteoblast and osteoclast were performed. RESULTS: The MTX release kinetics in vivo confirmed that MTX-CPC was a monolithic matrix system, with a burst effect in the initial stage and a sudden drop thereafter. The local concentration of the released MTX was 0.372 µg/ml on the 30th post-implantation day; with a concentration higher than the effective concentration,the incorporated MTX was expected to be continuously released over the following 2-3 months. Both MTX-CPC and CPC showed good biodegradability and osteoconduction. Although the release of MTX had an inhibitory effect on osteogenesis, especially in the initial stage, the area of newly formed bone, the amount of osteoblasts, and the amount of osteoclasts were not significantly different between MTX-CPC group and CPC group on the 6th post-implantation month. CONCLUSIONS: MPX-CPC system is an effective drug delivery system. Both MTX-CPC and CPC has good biodegradability and osteoconduction. Therefore,MTX-CPC system can be an ideal material for filling defects and controlling local recurrence.

[Spectral characteristics of Ba2B2P2O10 : Eu3+ phosphor].

Ba2B2P2O10 : Eu3+ phosphor was synthesized by high temperature solid-state method. BaCO3(A.R), NH4H2PO4 (A.R), H3BO3(A.R), Eu2O3 (99.99%), NH4Cl (A.R), Li2CO3 (A.R), Na2CO3 (A.R.) and K2CO3 (A.R.) were used for starting materials. After these individual materials were blended and grounded thoroughly in an agate mortar, the homogeneous mixture was heated at 1000 degrees C for 3 h, and the phosphors were obtained. The phase present of the samples were characterized by powder X-ray diffraction (XRD) (D/max-rA, Cu Kalpha, 40 kV, 40 mA, lamda = 0.15406 nm). The spectral characteristics of these phosphors were measured by a SHIMADZU RF-540 fluorescence spectrophotometer. Under the condition of 400 nm excitation, the emission spectrum of Ba2B2P2O10 : Eu3+ phosphor shows several bands at 600, 618, 627 and 660 nm respectively, which correspond to the electric dipole (5)D0-->(7)F1, (7)F2, (7)F3 and (7)F4 transitions of Eu3+. The effect of Eu3+ concentration or charge compensator on the emission intensity of Ba2B2P2O10 : Eu3+ phosphor was investigated, and the result shows that the emission intensity of the phosphor increases with increasing Eu3+ concentration, viz. the concentration quenching has not existed. And the emission intensity of the phosphor was enhanced by doping charge compensator. All the results illuminate that Ba2B2P2O10 : Eu3+ phosphor is a promising red phosphor for white LEDs.

[Spectral properties and energy transfer of Ce3+ and Tb3+ ions co-doped Ca2SrAl2O6 phosphor].

Ce3+, Tb3+ co-doped green phosphor Ca2SrAl2O6 was synthesized by solid state method and its excitation and emission spectra were measured and studied. The results showed that the emission spectrum is composed of four groups of narrow bands and the peaks are located at 497, 545, 595 and 623 nm. The strongest emission peak islocated at 545 nm and chromaticity coordinate (x, y) is (0.300 5, 0.500 2) at 4 mol% Ce3+ and Tb3+ doping, which indicate that Ca2SrAl2O6 : Ce3+, Tb3+ was a good green phosphor. The excitation spectrum for 545 nm was in the region of 320-400 nm, which indicated that this phosphor could be effectively excited by UVLED. Duo to the overlap of the Ce3+ emission bands and the Tb3+ excitation bands, the energy transfer between Ce3+ and Tb3+ is expected to be very efficient. The emission intensity of co-doped Ca2SrAl2O6 phosphor was stronger than that of Tb3+ doped phosphor. The luminescence intensity reached the maximum when the concentration of Ce3+ and Tb3+ was 4 mol%.

[Spectral characteristics of Ce3+ in alkali-alkaline earth borate system].

Alkali-alkaline earth borate LiCaBO3 : Ce3+, LiSrBO3 : Ce3+ and LiBaBO3 : Ce3+ were investigated by solid-state method. CaCO3 (99.9%), SrCO3 (99.9%), BaCO3 (99.9%), Li2 CO3 (99.9%), Na2 CO3 (99.9%), K2 CO3 (99.9%), H3BO3 (99.9%) and CeO2 (99.9%) were used as starting materials, After these individual materials were blended and ground thoroughly in an agate mortar, the homogeneous mixture was heated at 700 degrees C for 2 h in a reduced atmosphere (5 : 95 (H2/N2)), and these three phosphors were obtained. The excitation and emission spectra of these phosphors were measured by a SHIMADZU RF-540 fluorescence spectrophotometer. The spectral characteristics of Ce3+ in alkali-alkaline earth borate LiCaBO3, LiSrBO3 and LiBaBO3 were investigated. The emission spectra of Ce3+ in these three phosphors all exhibited a dissymmetrical band, and the emission peaks were located at 428, 436 and 440 nm, respectively. The excitation spectra for 428, 436 and 440 nm emission of these three phosphors showed a dissymmetrical band at 364, 369 and 370 nm, respectively. The effects of Li+, Na+ and K+ on the emission intensities of these three phosphors were studied. The results show that the emission intensities of these phosphors were enhanced, and the maximal emission intensity of doping Li+ is higher than that of Na+ and K+.

[Study of spectra characteristics of Dy3+ -activated LiSrBO3 phosphor].

The LiSrBO3:Dy3+ phosphor was synthesized by solid-state method. SrCO2 (99.9%), Li2CO3 (99.9%), H3BO3 (99.9%) and Dy2O3 (99.9%) were used as starting materials. After these individual materials were blended and grounded thoroughly in an agate mortar, the homogeneous mixture was heated at 700 degrees C for 2 h in air, and LiSrBO3:Dy3+ phosphors were obtained. The phase present of the samples was characterized by powder X-ray diffraction (XRD) (D/max-rA, Cu Kalpha, 40 kV, 40 mA, lamda = 0.15406 nm). The excitation and emission spectra of these phosphors were measured by a RF-540 photoluminescence spectrophotometer. The emission spectrum of LiSrBO3:Dy3+ phosphor shows several bands at 486, 578 and 668 nm, respectively. The excitation spectrum for 578 nm emission has several excitation bands at 331, 368, 397, 433, 462 and 478 nm, respectively. The effect of Dy3+ concentration on the emission intensity of LiSrBO3:Dy3+ was investigated, and the result shows that the emission intensity of LiSrBO3:Dy3+ phosphor firstly increases with increasing Dy2+ concentration, then decreases, viz. the concentration quenching exists. And the Dy3+ concentration corresponding to the maximal emission intensity is 3 mol%, and the concentration quenching mechanisms are the d-d interaction by Dexter theory.