[Activity comparison of humanized CD19 CAR-T cells with murine CD19 CAR-T on Nalm-6 cells and xenograft tumor model]

Objective: To compare the activity difference of the high affinity humanized CD19 chimeric antigen receptor (CAR)-T cells and murine CD19 CAR-T cells. Methods: Peripheral venous blood T cells from 8 healthy volunteers were collected and infected with humanized and murine CD19 CAR lentivirus. Human and murine CD19 CAR-T cells were prepared and cell proliferation was detected by cell counting kit-8 (CCK-8) method. The cytotoxicity of CD3(+) T cells, humanized and murine CD19 CAR-T cells to NALM-6 cells was detected by lactate dehydrogenase assay. Thirty BAL B/c nude mice transplanted with NALM-6 cells were randomly divided into 3 groups with 10 mice in each group and injected humanized CD19 CAR-T cells, mouse CD19 CAR-T cells and control CD3(+) T cell via tail vein, respectively. The proportion of NALM-6 cells in peripheral blood and the proportion of CD19 CAR-T cells in T cells from the vein of the inner canthus were detected by flow cytometry. The overall survival of BAL B/c nude mice was observed. Results: The proliferation of mouse and humanized CD19 CAR-T cells were (68.50±0.93)% and (80.63±1.41)%, respectively (t=20.353, P<0.001) after cultured in vitro for 24 hours, and were (91.38±1.41)% and (148.13±1.25)%, respectively (t=85.364, P<0.001) after cultured for 48 hours. When the effect to target ratio was 1∶1, there was no difference between the humanized and murine CD19 CAR-T cell group after co-culture for 24 hours (P=0.169), while the killing activity of humanized CD19 CAR-T cells against NALM-6 cells was higher than that of murine CD19 CAR-T cells (P<0.01) after 48 hours of co-culture. When the effect to target ratio was 4∶1, the cytotoxicity of humanized CD19 CAR-T cells against NALM-6 cells was higher than that of murine CD19 CAR-T cells in co-culture for 24 and 48 hours (P<0.01). On the seventh day of CD19 CAR-T cell therapy, the proportion of NALM-6 cells in the peripheral blood of BAL B/c nude mice decreased to the lowest level in the humanized CD19 CAR-T cell group and the murine CD19 CAR-T cell group. After 21 days, the proportion of NALM-6 cells in the murine CD19 CAR-T cell group was higher than that in the humanized CD19 CAR-T cell group (P(21 d)=0.001, P(28 d)<0.001, P(35 d)<0.001). The proportion of humanized and murine CD19 CAR-T cells in the peripheral blood reached the peaks after 7 days of therapy, and the proportion of humanized CD19 CAR-T cells was higher than that of murine CAR-T cells (P(7 d)=0.002). The CD19 CAR-T cells disappeared in the peripheral blood in the murine CD19 CAR-T cell group after 14 days of therapy, while in the humanized CD19 CAR-T cell group it disappeared after 21 days of therapy. The median survival of BAL B/c nude mice in the murine CD19 CAR-T cell group and the humanized CD19 CAR-T cell group was 42 days and 63 days, respectively (χ(2)=15.382, P<0.001). Conclusions: High affinity humanized CD19 CAR-T cells have stronger proliferation, higher cytotoxicity and longer survival time compared with those of murine CD19 CAR-T cells. The results indicate that the clinical efficacy of humanized CD19 CAR-T cells would be better than that of murine CD19 CAR-T cells.

[In vitro studies on the transfer of CAR into leukemia cells due to their residue in the autologous CAR-T cell preparation system for acute B-cell acute lymphoblastic leukemia]

Objective: To investigate the characteristics and cytotoxicity in vitro of the residual leukemia cells in the culture system that caused the accidental transfer of CD19 chimeric antigen receptor (CAR) into leukemia cells during the preparation of autologous CD19 CAR-T cells of relapsed/refractory B-cell acute lymphoblastic leukemia. Methods: ①Peripheral blood mononuclear cells (PBMC) of 30 patients with relapsed/refractory B-cell acute lymphoblastic anemia (R/R B-ALL) who accepted CD19 CAR-T cell therapy and six healthy volunteers were collected. ②The residual leukemia cells were analyzed by flow cytometry in the system after the PBMCs of R/R B-ALL patients were sorted by CD3 magnetic beads. ③ CD3(+) T cells from patients and healthy volunteers were transfected with CD19 CAR and CD22 CAR lentivirus to prepare CD19 CAR-T and CD22 CAR-T cells. ④The Nalm-6 cell line was resuscitated and the Nalm-6 cells with CD19 CAR lentivirus were transfected to prepare CD19 CAR-Nalm-6 cells. The patient's primary ALL cells were transfected with CD19 CAR lentivirus at the same time. ⑤The transfection rates were analyzed by flow cytometer, the cell proliferation was analyzed by the CCK-8 method, and the cell-killing activities were detected by the lactate dehydrogenase method. Results: ① Among the 30 R/R B-ALL patients who received CD19 CAR-T cell therapy, two patients had 2.04% and 3.32% residual leukemia cells in CD3(+) T cells. After 4 days in culture, the residual leukemia cells disappeared and could not be detected by a flow cytometer with prolonged cultivation in vitro. ② The proliferation of CD19 CAR-Nalm-6 cells was higher than that of the Nalm-6 cells. ③ The killing activity of the CD19 CAR-T cells on Nalm-6 cells was higher than that of the CD19 CAR-Nalm6 cells at a target ratio of 1∶1 on 24, 48, 72 h, respectively. The cytotoxicity of CD22 CAR-T cells on CD19 CAR-Nalm-6 cells was significantly higher than that of CD19 CAR-T cells. ④ The cytotoxicity of CD22 CAR-T alone on CD19 CAR-Nalm-6 cells was higher than that of CD19 CAR-T combined with CD22 CAR-T at the same target ratio. Conclusion: The residual leukemia cells in the culture system in the preparation of CD19 CAR-T cells may lead to the introduction of CD19 CAR into leukemia cells and results in the failure of the CD19 CAR-T cell therapy. Detecting the residual leukemia cells in the culture system via flow cytometry before transfection with CD19 CAR lentivirus is needed. Thus, CD22 CAR-T cell therapy could be used as one of the salvage treatments.

Disorder-Induced Broadband Near-Infrared Persistent and Photostimulated Luminescence in Mg2SnO4:Cr3

Materials with near-infrared (NIR) persistent luminescence (PersL) and NIR-to-NIR photostimulated luminescence (PSL) properties are attractive platforms for photonic energy harvesting and release. In this work, we develop Mg₂SnO₄:Cr as a broadband NIR PersL and NIR-to-NIR PSL material (luminescence maxima at ∼800 nm) and reveal the origin of the PersL and PSL properties. The material has an inverse spinel structure with the Mg²⁺ and Sn⁴⁺ disorder at the Wyckoff 16d site based on the Rietveld refinement. Cr K-edge X-ray absorption near-edge structure (XANES) spectra uncover that the doped Cr ions have a +3 valence state and occupy the disordered (Mg,Sn) site with octahedral coordination. The disorder results in multiple Cr³⁺ centers, and the broadband luminescence originates from the ⁴T₂(⁴F) → ⁴A₂ transition of Cr³⁺ at sites with intermediate crystal field strength. The distribution of trap depths is continuous according to the analysis of thermoluminescence (TL) spectra using the initial rising method, which relates to the random distribution of Mg²⁺ and Sn⁴⁺ at the second coordination sphere of the Cr³⁺ centers rather than the oxygen-related defects. Stimulating the material with a NIR laser, the NIR PersL gets significantly enhanced due to a PSL process. The broadband PersL and PSL are detectable beyond 100 h and have good tissue penetrability and therefore the developed Mg₂SnO₄:Cr³⁺ has potential in applications of optical information storage/reading and autofluorescence-free bioimaging. Finally, three crystal and electronic structure factors are proposed for screening new Cr³⁺-activated PersL and PSL materials.

[Analysis on poor efficacy factors in the treatment of recurrent/refractory B-cell lymphoma with CD19 CAR-T cells]

Objective: To investigate the factors influencing the efficacy of CD19 chimeric antigen receptor T (CAR-T) cells in the treatment of patients with relapsed refractory B cell lymphoma and to provide evidence for further improvement of CAR-T efficacy. Methods: A total of 34 patients with relapsed and refractory B-cell lymphoma were recruited from the Department of Hematology of Tianjin First Central Hospital from February 2017 to January 2019. All patients received CD19 CAR-T cell therapy. These patients were evaluated for efficacy, factors with poor efficacyand adverse effects. Results: The overall response rate was 58.8% (20/34) and the complete remission rate was 41.2% (14/34) after infusion of CD19 CAR-T cells in 34 patients with relapsed refractory B cell lymphoma. According to the efficacy of CAR-T cells, patients were divided into two groups, 20 in the effective group and 14 in the poorly effective group. The median am ount of CD19 CAR-T cell infusions in these two groups were 8.6 (5.0-12.7)×10(6)/kg and 9.7 (5.8-15.0) × 10(6)/kg, respectively, and the difference was not statistically significant (P=0.654). The percentage of CD19 CAR-T cells in the effective group and the poorly treated group was 10.28% (3.92%-44.16%) and 4.05% (0.92%-28.63%), respectively.The effective group had a higher proportion of CAR-T cells than the poorly treated group, but the difference was not statistically significant (P=0.371).The presence of massive mass was an unfavorable factor affecting the efficacy of CD19 CAR-T cells and the difference was statistically significant (P=0.001). Logistic regression multivariate analysis showed that the characteristics of massive tumors were still independent prognostic factors for poor efficacy of CD19 CAR-T cells (P=0.005, OR=0.039). Of all 34 patients, there were 70.6% (24/34) who showed varying degrees of adverse reactions after the infusion of CD19 CAR-T cells, mainly cytokines release syndrome (CRS). The median time of occurrence of fever was on the third day after infusion (0-11th) day. 16 patients were with grade 1 CRS, 7 with grade 2, and 1 with grade 3. After glucocorticoids and support treatment, they all showed improvements. Conclusions: CD19 CAR-T cell therapy has achieved a certain effect in CD19(+)B cell lymphoma, but has poor efficacy on some patients. Large mass tumors may be an adverse factors to CAR-T cell treatment.

[PD-1 expression, mRNA level and cytotoxicity changes in CD19CAR-T cells]

目的

探讨CD19 CAR-T细胞培养过程中其PD-1蛋白、mRNA水平及细胞杀伤活性变化。

方法

收集6例外周血PD-1高表达恶性淋巴瘤患者、6例健康志愿者的外周血T细胞，作为CAR-T培养的T细胞来源。流式细胞术检测PD-1蛋白表达、PCR法检测PD-1 mRNA水平，CCK-8法检测细胞增殖，LDH法检测细胞杀伤活性。

结果

①PD-1高表达患者T细胞来源CD19 CAR-T细胞，与志愿者T细胞来源者相比，转染率无差异（P>0.05）；②PD-1高表达T细胞来源CAR-T细胞与PD-1抑制剂联合与否，以及健康志愿者CAR-T之间，细胞增殖差异无统计学意义（P>0.05）；③PD-1高表达T细胞与CAR-T细胞对淋巴瘤细胞株杀伤活性，低于二者联合PD-1抑制剂及志愿者CAR-T细胞（P<0.001），而PD-1高表达T细胞来源CAR-T细胞联合PD-1抑制剂与健康志愿者CAR-T细胞间差异无统计学意义（P>0.05）；④各组细胞培养过程中PD-1表达均下降，差异无统计学意义（P>0.05），但各组细胞培养过程中，PD-1 mRNA的变化差异无统计学意义（P>0.05）；⑤PD-1高表达T细胞来源CAR-T收获后，与PD-1抑制剂共培养与否，其PD-1表达差异无统计学意义（P>0.05），但CAR-T与淋巴瘤细胞株接触后，其PD-1表达随培养时间延长而增高，加入PD-1抑制剂可拮抗该作用；各组间PD-1 mRNA的变化差异无统计学意义（P>0.05）。

结论

PD-1高表达T细胞来源CAR-T细胞与肿瘤细胞接触后，其PD-1表达随培养时间延长而增高；而包括PD-1抑制剂在内，不能改变其PD-1 mRNA的表达。

[The evaluation of modified cell infusion method to reduce febrile non-hemolytic transfusion reaction in CD(19) chimeric antigen receptor T cell threapy]

Objective: To retrospectively analyze the efficacy and safety of modified cell infusion method in reducing the incidence of febrile non-hemolytic transfusion reaction (FNHTR). Methods: A total of 69 patients were enrolled in the clinical trial of CD(19) chimeric antigen receptor T (CAR-T) cell treatment from February 2017 to October 2018. Study group received the modified cell infusion method, that 1×10(6) CAR-T cells were re-suspended in 2 mg human serum albumin with total volume of 20 ml and injected intravenously. The control group was intravenously administrated with CAR-T cell in 100 ml normal saline. The incidence of FNHTR, cytokine releasing syndrome (CRS) grade, cytokine level and efficacy were compared. Results: (1)The incidence of FNHTR in the study group was 21.1%, significantly lower than that in the control group (71%)(P=0.000). (2)There was no statistical difference in cell proliferation between the study group and the control group on day 4, 7, 14 and 21 after CAR-T cell infusion (P=10.223, 3.254, 5.551, 7.605). (3)There was no statistical difference in CRS grading between the study group and the control group (P=0.767). There was no statistical difference in the levels of interleukin 2 receptor (IL-2R), IL-6, tumor necrosis factor (TNF)-α between the two groups. (4)The C-reaction protein (CRP) level of the study group was lower than that of the control group on day 4 and 7 (P=0.026, 0.007). (5)There was no statistical difference of response rates in acute lymphocytic leukemia (ALL) and non-Hodgkin lymphoma (NHL) patients between the two groups (P(ALL)=0.842; P(NHL)=0.866). Conclusion: The modified cell infusion method in CD(19) CAR-T cell treatment reduces the incidence of treatment-related FNHTR. It does not affect the proliferation of CAR-T cells in vivo, the grading of CRS and the response rates.

[Efficacy and safety of CD19 chimeric antigen receptor T cells for the treatment of 22 patients with B-cell lymphoma]

目的

探讨CD19 CAR-T治疗B细胞淋巴瘤的疗效及安全性。

方法

评估2017年2月1日至2018年7月1日CD19 CAR-T治疗22例B细胞淋巴瘤患者的疗效及不良反应情况。

结果

22例患者输注CD19 CAR-T后，总体完全缓解（CR）率为45.5%，部分缓解（PR）率为31.8%，总有效率为77.3%。其中12例复发难治患者9例有效，2例达CR，7例PR；10例微小残留病（MRD）阳性患者，8例MRD转阴。全部患者外周血中均检测到CD19 CAR-T细胞在体内增殖，复发难治患者与MRD阳性患者T细胞增殖的达峰时间分别为治疗后第4.5（1~12）天和治疗后第12（5~19）天，外周血CAR-T细胞分别占总的T淋巴细胞的4.02%（2.23%~28.60%）和10.10%（3.55%~24.74%）。MRD转阴患者持续缓解，中位随访8（3~18）个月均未复发，且此组患者有3例联合PD-1抗体治疗，均达CR。复发难治患者中，7例CAR-T治疗后达PR患者疗效保持时间为1.5~6.0个月，PD-1表达率为25.7%~55.3%，5例CAR-T治疗无效患者PD-1均高表达；共有3例患者联合应用PD-1抗体，其中2例有效；2例CAR-T治疗后达CR患者中1例行异基因造血干细胞移植，另1例随访12个月仍持续缓解。22例患者输注CAR-T细胞后14例发生不同程度的细胞因子释放综合征（CRS），其中9例为1级CRS，4例为2级CRS，其中1例复发难治患者发生3级CRS，经糖皮质激素、IL-6抗体治疗后CRS得到控制。治疗有效的17例患者中14例发生CRS，治疗无效的5例患者均未发生CRS。难治复发患者发生CRS的严重程度高于MRD阳性患者。

结论

CD19 CAR-T在CD19⁺ B细胞淋巴瘤中取得了疗效。CAR-T联合免疫检查点抑制剂的应用能够更好地提高疗效，CAR-T细胞治疗可作为复发难治患者的挽救治疗，清除B细胞淋巴瘤的MRD效果更好且不良反应小。

Synthesis and luminescence of novel near-infrared emitting BaZrSi3 O9 :Cr3+ phosphors

The BaZrSi₃ O₉ :Cr³⁺ phosphors were prepared by a high temperature solid state method. Their structures were confirmed with XRD and their luminescence properties were investigated. Under excitation at 455 nm, BaZrSi₃ O₉ :Cr³⁺ phosphors exhibited a broad near infrared emission band peaked at 800 nm, which was assigned to the ⁴ T₂ →⁴ A₂ transition of Cr³⁺ . The near infrared emission intensity reached a maximum at Cr³⁺ concentration of 0.7%. There was a concentration quenching phenomenon of Cr³⁺ in BaZrSi₃ O₉ matrix and the corresponding concentration quenching mechanism was investigated. With efficient near infrared emission in the range of 700-1000 nm, BaZrSi₃ O₉ :Cr³⁺ phosphors may find applications in solar energy conversion.

[Establishment of macrophage model of iron overload in vitro and the injury induced by oxidative stress on macrophage with iron overload]

OBJECTIVE

To establish macrophage iron overload model in vitro by co-culture macrophages with iron, and to explore the effect of iron overload on cell reactive oxygen species (ROS) and the impact of ROS on macrophages.

METHOD

Iron overload group were treated with different concentrations (0, 5, 10, 20, 40, 80 μmol/L respectively) of ferric ammonium citrate (FAC). The control group was the group of macrophages without FAC treatment. We detected the number and state of cells, metabolic activity, the change of phagocytosis, the levels of ROS and reactive nitrogen, and changes of related oxidative stress signaling pathways in different groups. Changes in the above indexes were detected after application of deferasirox (DFX) to remove iron and the antioxidant N -acetylcysteine (NAC) to clear excess oxidative stress.

RESULTS

(1)The levels of labile iron pool (LIP) in macrophages co-cultivated with iron was increased with the increase of iron concentration in a dose-dependent manner. The LIP levels was the highest in the macrophages treated with 80 μmol/L. (2)The increase of FAC concentration, the metabolic activity of macrophages in the 5 FAC-treated groups decreased to 51.58%, 40.98%, 16.23%, 3.46%, and 0.05% of the activity level of the control group (all P< 0.05). The group with the metabolic activity decreased to 16.23% (20 μmol/L) was selected as the iron overload group for the following experiments. (3)Compared with the control group, the number of macrophages in the iron overload group reduced to 32.80% (P<0.05), and the state of cells changed from adherence to partial suspension. The phagocytosis of macrophages in the iron overload group reduced to 20.40% of the control group (P<0.05). (4)Our further experiment showed that the levels of ROS and the activity nitrogen in the iron overload group increased by 7.71-and 1.45-fold compared with the control group (both P<0.05). The RT-PCR showed up-regulated mRNA expression of genes related with ROS production, i. e. nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX 4) gene related with ROS production and inducible nitric oxide synthase (iNOS) gene related with reactive nitrogen production, down-regulated mRNA expression of glutathione peroxidase 1 (GPX1) gene which participated in ROS clearance. Moreover, mRNA expression of phosphatidylinositol-3-kinase (PI3K) gene involved in oxidative stress signaling pathway in the iron overload group was up-regulated, while fork head protein O3 (FOXO3) which regulated oxidative stress through negative feedback showed a down-regulation level of mRNA expression compared with the control group. (5)After iron chelation and antioxidant treatment, the above-mentioned damage in the iron overload group were partially reversed.

CONCLUSIONS

The damages of iron overload on macrophages may be mediated by inducing oxidative stress and activating oxidative stress signaling pathways. Our established model provides a method to explore the mechanism of iron overload on macrophage, and may shed some new light on possible therapeutic target in treating iron overload patients.

[Near-infrared luminescence and energy transfer of ACaPO4 : Eu2+, Nd3+ (A = Li, K, Na)]

Near-infrared (NIR) luminescence phosphors ACaPO4 : Eu2+, Nd2+ (A = Li, K, Na) were prepared by conventional solid state method and the sensitization of Nd3+ near-infrared luminescence by Eu2+ was investigated. The characteristic NIR luminescence of Nd3+ in ACaPO4 matrix is greatly enhanced by co-doping of Eu2+. The fluorescence properties of ACaPO4 : Eu2+, the NIR luminescence properties of ACaPO4 : Eu2+, Nd3+ and the fluorescence lifetime were studied. The effect of emission wavelength of Eu2+ on NIR luminescence of Nd3+ was investigated; The energy transfer mechanism between Eu2+ and Nd3+ was also discussed. Emission peak wavelength of Eu2+ In ACaPO4 matrixes was found red shift with the series of A = Li, K, Na and the extent of the overlap with the different excitation peaks of Nd3+ changes obviously. It was concluded that the emission peak position of Eu2+ is a very important factor for energy transfer, and the optimal wavelength range for Eu2+ --> Nd3+ energy transfer is 500 to 550 nm.

[Near-infrared fluorescence and energy transfer in Sr2SiO4 : Eu2+, Nd3+]

Sr2 SiO4 : Eu2+ , Nd3+ was synthesized by solid state synthesis method, and the sensitization of Nd3+ near-infrared luminescence by Eu2+ was investigated. The characteristic near-infrared luminescence of Nd2+ in Sr2 SiO4 matrix was greatly enhanced by co-doping of Eu2+. The mechanism of energy transfer from Eu2+ to Nd3+ was analyzed through investigation of fluorescence excitation and emission spectra, and fluorescence lifetime. Excited Eu2+ (II) transfers energy effectively to Nd3+ through non-radiative energy transfer process in Sr2SiO4, resulting in greatly enhanced near-infrared luminescence of Nd3+, while sensitization of Nd3+ by Eu2+ (I) was achieved by the way of Eu2+ (II).

Synthesis of Y2O2S:Eu3+, Mg2+, Ti4+ hollow microspheres via homogeneous precipitation route

A phosphorescent material in the form of Y₂O₂S:Eu³⁺, Mg²⁺, Ti⁴⁺ hollow microspheres was prepared by homogeneous precipitation using monodispersed carbon spheres as hard templates. Y₂O₃:Eu³⁺ hollow microspheres were first synthesized to serve as the precursor. Y₂O₂S:Eu³⁺, Mg²⁺, Ti⁴⁺ powders were obtained by calcinating the precursor in a CS₂ atmosphere. The crystal structure, morphology and optical properties of the composites were characterized. X-ray diffraction measurements confirmed the purity of the Y₂O₂S phase. Electron microscopy observations revealed that the Y₂O₂S:Eu³⁺, Mg²⁺, Ti⁴⁺ particles inherited the hollow spherical shape from the precursor after being calcined in a CS₂ atmosphere and that they had a diameter of 350-450 nm and a wall thickness of about 50-80 nm. After ultraviolet radiation at 265 or 325 nm for 5 min, the particles emitted strong red long-lifetime phosphorescence originating from Eu³⁺ ions. This phosphorescence is associated with the trapping of charge carriers by Ti⁴⁺ and Mg²⁺ ions.

[PEG assisted hydrothermal synthesis of LaPO4 : Eu3+ nanoparticles]

The present reports a hydrothermal process to synthesize the precursor of Eu(3+)-doped LaPO4 nanoparticles with PEG2000 used as additive. SEM shows that the nanoparticles are similar to spheres. The Eu(3+-)doped LaPO4 phosphor was characterized by powder X-ray diffractometer. According to our measurements with XRD, the products belong to monoclinic monazite type, and the samples were well crystallized after sintering at 700 degrees C for 2 h. The effects of synthesis condition, sintering temperature and time on the luminescence of the samples were investigated. The luminescence data indicated that the optimum condition for synthesizing the precursor was at 180 degrees C for 14 h, and the optimum condition for heat-treatment of the precursor was at 850 degrees C for 1 hour. The effects of different contents of Eu3+ on the luminescence of LaPO4 : EuO3+ nanoparticles were also investigated, and the results showed that the luminescence intensity was enhanced with the slight increase in the Eu3+ content, and the optimum Eu(3+)-doping concentration was 4% (mole fraction).

[Preparation and characterization of long-afterglow nanophosphors CaTiO3 : Pr]

CaTiO3 : Pr nanophosphors were prepared with a gel-network precipitation technique using cheap inorganic precursors. The samples, being well dispersed and sphere-like with an average diameter of 100 nm, were observed with transmission electron microscope (TEM). The mechanism of coprecipitation and crystallization was discussed briefly based on TG-DTA and the X-ray diffractometer (XRD) results. The luminescent properties were investigated by the fluorescence spectrophotometer. The conditions of the preparation process were also studied systematically and the optimal conditions were concluded. The results show that the products with strongest luminescence intensity could be prepared at 1 100 degrees C for one hour, and the luminescent features of samples synthesized by the gel-network precipitation technique are similar to those by solid-state reaction, while the calcining temperature is reduced about 200 degrees C. In conclusion, uniform long-afterglow nanophosphors CaTiO3 : Pr were successfully synthesized with simple apparatus at low cost.

Hydrothermal preparation and luminescence of LaF3:Eu3+ nanoparticles

LaF3:Eu3+ nanoparticles were prepared by a simple hydrothermal process at low temperature and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and fluorescence spectrum. Well-dispersed nanoparticles with an average size of 30 nm and a hexagonal shape were obtained. The influences of reaction temperature and time on the preparation and luminescence of LaF3:Eu3+ nanoparticles were investigated. Luminescent quenching occurred at a much higher concentration ( approximately 25mol%) and stronger luminescent intensity than in bulk LaF3:Eu3+. Fluorescence intensity of the LaF3:Eu3+ nanoparticles varied remarkably with calcination temperatures. It was found that samples without any further calcinations can emit quite strong fluorescence.

Determination of chlorine in atmosphere by kinetic spectrophotometry

A kinetic method for determination of chlorine in air was described in the present work. The method based on fading of methyl orange (MO) containing solution in air absorption process. A determination limit of 2.64 microg L(-1) was found. With the present method, chlorine concentration could be determined in several minutes with convenient manipulation. As concentration variation of methyl orange in the absorption solution did not affect the experimental results, fabrication and preservation of the stock absorption is also convenient. The present method is promising in monitoring chlorine concentration in atmosphere.

Fluorimetry determination of trace Ce3+ with EDTP

The use of ethylenediaminetetrakis(methylphosphonic) acid (EDTP) in the fluorimetry determination of trace amounts of Ce3+ ions is described. The fluorescence intensity of Ce3+ was greatly enhanced when an 1:1 complex with EDTP in solution of pH 7-8 formed. The apparent excitation and emission wavelength used were 313 and 397 nm, respectively. The fluorescence intensity varied linearly with the concentration of Ce3+ in the range of 1 x 10(-8) -1 x 10(-4) mol l(-1). The quenching effects of coexist ions (other rare earth ions, Fe3+ and some inorganic anions) were studied. This technique has unique advantage in eliminating disturb of coexist.

Study on the binding of cerium(III) ion and spermine to TRNA(Phe)

Fluorescence of Ce(III) aqua ion at pH 6.0 is found to be in good linear relationship with its concentration, and the intensity is strong enough to be employed to determine its concentration. TRNA(Phe) evidently quench this fluorescence. Fluorescence titration experiments were performed to Ce(III)-tRNA(Phe) system, the binding number and association constant was estimated with a Scatchard plot. Two classes of binding sites with association constant of 5.2 x 10(7) and 4.4 x 10(6) M, respectively, were found. Addition of spermine slightly decrease binding number and association constant of Ce(III) ion.

Urinary and biliary metabolites of pyrene in rainbow trout (Oncorhynchus mykiss)

1. Pyrene was administered i.p. as a single dose to trout (Oncorhynchus mykiss). Urine was collected continuously for 3 days and bile sampled at the end of this period. Pyrene metabolites in these biological fluids were identified by 1H-nmr spectrometry, glc-ms and hplc-ms. 2. 1-Hydroxypyrene was the major oxidation metabolite in the urine and bile. Small amounts of 1,6-dihydroxypyrene and a putative 1,8-dihydroxypyrene metabolite also were detected. Unchanged pyrene was not found in any of these biological fluids. 3. Both free and conjugated metabolites of pyrene were found in the bile and urine. The majority of the pyrene metabolites in the bile were conjugated with glucuronic acid or sulphate.

[Study on dissolution rate of injection of microencapsulated compound megestrol acetate]

Dissolution rate of megestrol acetate in the injection of microencapsulated compound megestrol acetate was determined by the first derivative spectrum amplitude method. The experimental results reveal that t50 of the microencapsulated sample (I) is about 60.16 d, while the broken microencapsulated sample (II) is about 15.89 d and the unmicroencapsulated sample (III) about 15.87 d. The difference is regarded as of obvious significance (P less than 0.01). The values of the dissolution rate were linear with the parameters of rabbits and women both in vivo.