药皮组分对FV520(B)焊条工艺性能的影响

釆用均匀设计法研究了药皮中大理石、萤石以及大理石和石英交互作用对FV520(B)不锈钢焊条的发红性、脱渣性以及飞溅性的影响。结果表明:随着焊条药皮中萤石含量的增加,FV520(B)焊条的发红程度增大,且脱渣性变差,但飞溅减小;随着药皮中大理石含量的增加,FV520(B)焊条的发红程度先减小后再增大,而脱渣性是先变好后又变差,飞溅则是逐渐增大。而药皮中大理石和石英比值的增大使得FV520(B)焊条的发红程度先增大后减小,当其比值为6.14时,焊条的发红程度最大;焊条的脱渣性随着比值的增大先逐渐变好后再变差;而飞溅则是随比值的增大而增大。

新型抗发红不锈钢焊条的研制

本方主要阐述了在国产Ａ１３２不锈钢焊条原有药皮配方的基础上．引入稀土氧化物等新组分．通过各项性能测试得到了较满意的新配方．从而解决了国产焊条的发红问题。

Luminescent properties of Lu_2MoO_6:Eu^(3+) red phosphor for solid state lighting

The Eu^3＋ activated Lu2MoO6 phosphors were synthesized by high-temperature solid-state reaction method. The X-ray diffraction （XRD）, excitation spectra, emission spectra and decay lifetime of the phosphors were measured to characterize the structure and luminescent properties. The XRD results show that all the prepared phosphors can be assigned to the monoclinic structure. The experimental results indicate efficient absorption of near ultraviolet light from the Mo^6＋O^2- group followed by intensive emission in the visible spectral range. The optimal content of Eu3＋ is 10% （mole fraction）. The critical distance Rc and energy transfer mechanism were also discussed in detail. This red emitting material may be applied as a promising red phosphor for the near ultraviolet excited white light emitting diodes.

Pistillate Flower Development and Stigma Receptivity of Euphorbia pulcherrima

Objective] This study aimed to investigate the relationship between pistil-late flower developmental morphology and stigma receptivity in Euphorbia pulcherri-ma. [Method] One-year-old adult plants of E. pulcherrima cultivar ‘Mil enium’ were used as experimental materials to analyze pistil ate flower development process by macroscopic and scanning electron microscope （SEM） observation. Stigma receptivity was detected with benzidine-hydrogen peroxide method and in vivo pol en germina-tion method. [Result] The pistil ate flower development process of E. pulcherrima was consisted of columnar stigma phase, stigma lobe slightly opening phase, Y-shape stigma lobe phase, inverse V-shaped stigma lobe phase and stigma curling phase. Pistil ate flower development and stigma receptivity of E. pulcherrima exhibit-ed certain correlation. The stigma receptive period lasted from stigma lobe slightly opening phase to inverse V-shaped stigma lobe phase; inverse V-shaped stigma lobe phase was appropriate for pol ination, lasting for 3-5 d, with V-shaped stigma lobe and a large amount of exudates on stigma surface according to SEM obser-vation. Stigma receptivity of E. pulcherrima detected with benzidine-hydrogen perox-ide method was consistent with that detected in vivo pol en germination method. [Conclusion] ln breeding practice, the optimal pol ination period of E. pulcherrima can be determined based on the developmental morphology of pistil ate flower.

Pure red cell aplasia due to parvovirus B19 infection after liver transplantation:A case report and review of the literature

Pure red cell aplasia （PRCA） due to parvovirus B19 （PVB19） infectiori after solid organ transplantation has been rarely reported and most of the cases were renal transplant recipients, Few have been described after liver transplantation. Moreover, little information on the management of this easily recurring disease is available at present. We describe the first case of a Chinese liver transplant recipient with PVB19-induced PRCA during immunosuppressive therapy. The patient suffered from progressive anemia with the lowest hemoglobin level of 21 g/L. Bone marrow biopsy showed selectively inhibited erythropoiesis with giant pronormoblasts. Detection of PVB19-DNA in serum with quantitative polymerase chain reaction （PCR） revealed a high level of viral load. After 2 courses of intravenous immunoglobulin （IVIG） therapy, bone marrow erythropoiesis recovered with his hemoglobin level increased to 123 g/L. He had a lowlevel PVB19 load for a 5-too follow-up period without recurrence of PRCA, and finally the virus was cleared. Our case indicates that clearance of PVB19 by IVIG in transplant recipients might be delayed after recovery of anemia.

Screening, Identification and Fermentation Property of a Yeast Strain R6 Accumulating Alpha-ketoglutaric Acid

A yeast strain R6 was obtained by the method of thiamine（VB1） auxotrophic negative selection from the edible oil-polluted soil in Zibo, China. Physiological and biochemical experiments revealed that strain R6 shared common feature with Rhodotorula mucilaginosa according to the API 20 C AUX yeast identification system which has been tested previously. Furthermore, the 18 S r DNA gene of strain R6 was amplified and sequenced. Phylogenetic analysis based on the 18 S r DNA sequence and the relatives indicated that R6 shared 99% homologies with the members of R. mucilaginosa, suggesting that strain R6 belonged to R. mucilaginosa.Investigation showed that strain R6 possessed the capacity of accumulating exocellular alpha-ketoglutaric acid（alpha-KG）. Finally, the fermentation conditions of R6 to accumulate alpha-KG was optimized by controlling each single fermenting variable and detected through high performance liquid chromatography（HPLC）. Results showed that both VB1 and Ca CO3 in fermentation medium were the key factors influencing the cumulant of alpha-KG. The discovery of natural auxotrophic strain R6 not only broadened the microbial resource which can achieve lots of alpha-KG production through fermentation, but also laid a foundation for further fermentation regulation to achieve excessive alpha-KG accumulation.

Insight into catalytic properties of Co3O4-CeO2 binary oxides for propane total oxidation

A series of Co3O4-CeO2 binary oxides with various Co/(Ce+Co)molar ratios were synthesized using a citric acid method,and their catalytic properties toward the total oxidation of propane were examined.The activities of the catalysts decrease in the order CoCeOx-70>CoCeOx-90>Co3O4>CoCeOx-50>CoCeOx-20>CeO2.CoCeOx-70(Co/(Ce+Co)=70% molar ratio)exhibits the highest catalytic activity toward the total oxidation of propane,of which the T90 is 310℃(GHSV=120000 mL h^-1 g^-1],which is 25℃ lower than that of pure Co3 O4.The enhancement of the catalytic performance of CoCeOx-70 is attributed to the strong interaction between CeO2 and Co3O4,the improvement of the low-temperature reducibility,and the increase in the number of active oxygen species.In-situ DRIFTS and reaction kinetics measurement reveal that Ce addition does not change the reaction mechanism,but promotes the adsorption and activation of propane on the catalyst surface.The addition of water vapor and CO2 in reactant gas has a negative effect on the propane conversion,and the catalyst is more sensitive to water vapor than to CO2.In addition,CoCeOx-70 exhibits excellent stability and reusability in water vapor and CO2 atmosphere.

Antimicrobial Activity in Kombucha Fermentation Broth

[Objective] The aim was to study if the fermentation broth of Kombucha has protein with antimicrobial activity. [Method] The effects of different cultivation time on cell concentration, pH, total protein concentration and inhibition zone were studied. The fermentation broth of Kombucha on the sixth day was adjusted to different pH. Fermentation broth treated with protease was put into the plates of Escherichia co/i, Bacillus cereue and Staphylococcus aureus as control, as well as ampenicilin. The zone of broth inhibition was measured. [ Result] The concentration of general protein was of positive relevance to the antimicrobial activity of Kombucha fermentation broth. The zone of inhibition decreased with rising pH and was the lowest when pH was 7. Later, as pH increasing, it enlarged. The inhibition effect of processed protease reduced remarkably. [ Conclusion] The fermentation broth of Kombucha revealed antimicrobial proteins.

Clinical analysis of 78 cases of paroxysmal nocturnal hemoglobinuria diagnosed in the past ten years

OBJECTIVE: To learn more about the clinical and laboratory features of patients with paroxysmal nocturnal hemoglobinuria (PNH) diagnosed in the past ten years. METHODS: Clinical and laboratory data for 78 cases of PNH diagnosed from January 1990 to November 1999 in our hospital were analyzed retrospectively. RESULTS: In comparison with PNH cases reported in the 1980s, the newly diagnosed PNH cases showed the following features: (1) older age of disease onset (from 27 to 34 years); more female cases (from 18.5% to 38.5%); more cases without hemoglobinuria (from 24.2% to 38.5%). (2) No positive family hereditary history. (3) Bone marrow dysplasia, abnormal karyotype and negative sister chromatid differentiation were found in 19.2%, 12.2% and 8.9% of the PNH patients, respectively. 12.3% of the patients had bone marrow hypoplasia, and most of them had no hemoglobinuria. Ham's tests were negative in about 34.2% of the cases. CD55 and CD59 on peripheral blood cells were deficient in 100.0% of the cases, suggesting that CD55 and CD59 tests can improve the diagnosis of PNH. (4) Adrenocortical hormone was effective in 83.8% of the patients, 54.2% of whom relapsed within one year. Eight refractory and relapsed patients were treated with low dose chemotherapy (MP therapy: Melphalan 2 - 6 mg x d(-1); Prednisone 0.5 mg x kg(-1) x d(-1)). Five (62.5%) of them showed positive responses. Bone marrow failure and other side effects were not serious in this group of patients. CONCLUSIONS: PNH, an acquired blood disease seen more often among adult males, can be diagnosed more sensitively by hemocyte member CD55 and CD59 tests and treated more effectively with adrenocortical hormone or low dose chemotherapy.

Inhibiting effects of low-molecular weight heparin and adrenocortical hormone on hemolysis of red cells in patients with paroxysmal nocturnal hemoglobinuria in vitro

OBJECTIVE: To study the effects of low-molecular weight heparin (LMWH) and adrenocortical hormone (dexamethasone) on the hemolysis of red cells of patients with paroxysmal nocturnal hemoglobinuria (PNH) in vitro. METHODS: Using Ham's test and micro-complement lysis sensitive test (mCLST), the changes in hemolysis of red cells from 6 typical PNH cases were examined after adding LMWH and dexamethasone in different concentrations into the test solution in vitro. The effects of LMWH and dexamethasone on the coagulation of the tested blood samples were also studied using the activated partial thromboplastin time (APTT) test. RESULTS: Both LMWH and dexamethasone inhibited the hemolysis of PNH red cells, and they also showed a synergistic effect. The inhibiting effects were dose-dependent. Moreover, a tolerable dose of LMWH induced a limited prolongation of APTT. Dexamethasone showed two possible mechanisms in the inhibition of PNH red cells hemolysis through Ham's test and mCLST, respectively: (1) inhibiting both antibodies binding to red cells and (2) the initiation of the activation of complement 3 (C3). LMWH could inhibit hemolysis as determined by both Ham's test and mCLST, which indicated that LMWH could block the activation of complement cascade. CONCLUSIONS: Both LMWH and dexamethasone could inhibit hemolysis in PNH, and they showed a synergistic effect. Their mechanisms of inhibiting hemolysis differed from each other. Furthermore, a tolerable dose of LMWH induced a limited prolongation of APTT. LMWH might be useful for controlling acute hemolysis in patients with PNH and reducing the dose of adrenocortical hormone.

Phenotypic analysis of affected peripheral erythroid for CD59 in paroxysmal nocturnal hemoglobinuria

OBJECTIVE: To determine whether affected reticulocytes could be a reliable marker for the diagnosis of paroxysmal nocturnal hemoglobinuria (PNH), we analyzed CD59-antigen expression on the membranes of reticulocytes and erythrocytes. METHODS: We studied 10 PNH patients and 5 healthy volunteers by two-color flow cytometry with a membrane permeable fluorescent dye, thiazole orange (TO), and anti-CD59 monoclonal antibodies (MoAb). TO was introduced to gate reticulocytes and anti-CD59 MoAb were used to identify glycosylphosphatidylinositol (GPI)-deficient cells. RESULTS: Cells from healthy individuals were only CD59 positive. However, in all PNH patients, CD59-antigen expression could be divided into 3 types: type I cells (CD59 normally positive), type II cells (CD59 partly positive) and type III cells (CD59 negative). The majority of reticulocytes belonged to type III cells, GPI-deficient cells (61.0%). In addition, the percentage of affected reticulocytes was higher than that of erythrocytes. CONCLUSIONS: Analyzing PNH reticulocytes was important, because most patients had elevated numbers of reticulocytes, which represent more closely the recent erythroid output of BM. However, circulating mature erythrocytes were subject to complement-mediated intravascular lysis. Therefore, the percentage of abnormal erythrocytes may not accurately reflect the proliferation rate of normal and abnormal erythroid progenitor cells. Thus, affected reticulocytes could be a more reliable indicator for the diagnosis of PNH than mature erythrocytes.

Phase transition and photoluminescence properties of Eu^3＋-doped ZnMoO4 red phosphors

Eu3＋-doped ZnMoO4 with different doping concentrations were synthesized by a hydrothermal method. The effects of Eu3＋ doping on the phase structure and photoluminescence （PL） properties of ZnMoO4 were investigated. The result showed that the introduction of Eu3~ could lead to phase transition of ZnMoO4. With the increase of Eu3-- doping amount, [3-ZnMoO4 was transformed to ct phase gradually, which led to different photoluminescence performances. The optimized doping concentration of Eu3＋ was 6 mol% for the highest emission intensity at 615 nm. Its CIE chromaticity coordinates were （0.667, 0.331）, which were very close to the values of standard chromaticity （0.67, 0.33） for National Television Standards Committee （NTSC） system. Therefore, Eu3＋-doped ZnMoO4 is considered to be a promising red-emitting phosphor for white LED applications.

Lanthanide-doped near-infrared Ⅱ luminescent nanoprobes for bioapplications

Luminescent biosensing in the second nearinfrared(NIR-II) region is featured with superior spatial resolution and high penetration depth by virtue of the suppressed scattering of long-wavelength photons. Hitherto, the reported NIR-II nanoprobes are mostly based on carbon nanotubes, organic fluorophores or semiconducting quantum dots. As an alternative, trivalent lanthanide ions(Ln3+) doped nanoparticles have been emerging as a novel class of promising nanoprobes. In this review, we highlight the recent progress in the design of highly efficient Ln3+-doped NIR-II nanoparticles towards their emerging bioapplications, with an emphasis on autofluorescence-free bioimaging, sensitive bioassay, and accurate temperature sensing. Moreover, some efforts and challenges towards this rapidly expanding field are envisioned.

Magnetic and optical properties of NaGdF4：Nd^3＋, Yb^3＋, Tm^3＋ nanocrystals with upconversion/downconversion luminescence from visible to the near-infrared second window

We have designed and synthesized NaGdF4：Nd^3＋, Yb^3＋, Tm^3＋. magnetic nano- phosphors with combined dual-mode downconversion （DC） and upconversion （UC） photoluminescence upon 800 run excitation. Hexagonal-phase NaGdF4：Nd^3＋, Yb^3＋, Tm^3＋ nanocrystals （NCs） with an average size of 21 nm were synthesized using a solvothermal approach. Nd^3＋, Yb^3＋, Tm^3＋ triple-doped NaGdF4 NCs exhibit a broad range of photoluminescence peaks covering a near infrared first/second window （860-900, 1,000, and 1,060 nm）, and visible emission including blue （475 nm）, green （520 and 542 nm） and yellow （587 nm） after excitation at 800 nm. A mechanism involving circulation of energy over Gd^3＋ sublattices as bridge ions and final trapping by the initial activator ions （Nd^3＋） has been proposed. Penetration depth studies indicate that NIR emission is easily detected even at a large tissue thickness of 10 mm. These paramagnetic nanophosphors demonstrate a large magnetization value of 1.88 emu/g at 20 kOe and longitudinal relaxivity value of 1.2537 mM-1.S-1 as a Tl-weighted magnetic resonance imaging contrast agent. These NaGdF4：Nd^3＋, Yb^3＋ Tm^3＋ NCs are promising for applications in biological and magnetic resonance imaging.

Synthesis and luminescence properties of red-emitting M_2Si_5N_8:Eu^(2+)-based(M=Ca,Sr,Ba) phosphors by a simple nitrate reduction

M2SisN8：Eu2＋-based （M=Ca, Sr, Ba） red-emitting phosphors are fabricated at relatively low temperature （1200℃） and atmos- pheric pressure using a simple solid-state reaction process. Several processing parameters are systematically investigated to optimize the phosphors structural characterization and photoluminescence performance, including the amount of europium and the properties of the precursor materials. The as-prepared M2SisNs：Eu2＋-based （M=Ca, Sr, Ba） phosphors are orange in color and are intensively emitted in the red region of 580-670 nm under 465 nm excitation.

Reversible enhanced upconversion luminescence by thermal and electric fields in lanthanide ions doped ferroelectric nanocomposites

Luminescence modification of lanthanide ions has attracted great attention due to its applications in sensing,colorful display, information transmission and anti-counterfeiting. Traditional methods of tuning fluorescence typically employ tuning compositions that are not conducive to the development of multi-environment detection and anti-counterfeiting. In this study, lanthanide ions doped ferroelectric nanocomposite was exploited with external stimuli. The upconversion luminescence modification was preformed via both the thermal and electric fields. The anti-thermal quenching phenomenon was observed in the prepared nanocomposite, which could effectively enhance the upconversion luminescence of lanthanide ions. Based on the electromechanical softness of the ferroelectric lattice, exceptional luminescence modification was realized through electric polarization. The luminescence modifications by thermal and electric fields exhibited excellent reversibility and non-volatility. These results provide unique insights into the development of integrated stimulus responsive smart devices, colorful display and advanced multi-mode sensing materials.

Red fluorescent siloles with aggregation-enhanced emission characteristics

A series of new red fluorescent siloles consisting of a silole core and dimesitylboranyl substituent connected with a furan, thiophene, and selenophene bridges were synthesized and characterized. The optical properties, electronic structures, and electroluminescence （EL） performances were investigated. The emission wavelengths were red-shifted from the siloles with furan, to those with thiophene, and then selenophene. The thiophene, and selenophene-containing siloles, （MesB）2DTTPS, and （MesB）zDSTPS, showed the typical aggregation-enhanced emission （AEE） feature, while furan-containing one, （MesB）2DFTPS, showed slight emission decrease as the aggregate formation. Theoretical calculations were carried out to explain the difference in the optical properties. Undoped OLEDs using these red siloles as light-emitting layers were fabricated. The device of （MesB）2DTTPS exhibited the best performance. It radiated red EL emission at 589 nm, and afforded good maximum luminance, current, power, and external quantum efficiency of 13300 cd m^-2, 4.3 cd A^-1, 2.9 lm W^-1, and 1.8%, respectively.

Optical characteristics and environmental pollutants detection of porous silicon microcavities

Porous silicon microcavities (PSM) optical crystals consisting of a Fabry-Perot microcavity embedded between two distributed Bragg reflectors have been fabricated by electrochemical etching. Scanning electron microscopy (SEM) clearly depicted their physical sandwich construction. The optical feature of the PSM structure was tuned by varying the anodization parameters. Through proper thermal oxidation and surface chemical modifications, the resulting structures were employed as optical sensors for the detection of environmental pollutants including volatile organic vapors (i.e. acetonitrile, toluene, cyclohexane, chloroform, acetone and ethanol) and interior decoration gases (i.e. toluene, ammonia and formaldehyde). Fourier transform infrared spectroscopy (FTIR) spectra confirmed the effective thermal annealing and surface modification chemistry, and the sensing process was accompanied by recording the modified structures' optical responses when exposed to target analytes. The PSM optical sensors showed good stability, sensitivity and selectivity, implying promising applications in gas sensing and en- vironmental monitoring.