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101.
A vertebrate host becomes infected with Leishmania major when the sand fly vector injects parasites into skin along with saliva. Previous studies showed that salivary gland lysate of the New World sand fly Lutzomyia longipalpis markedly enhanced L. major infection in CBA mice. However, L. major is an Old World parasite transmitted in nature by the Old World sand fly Phlebotomus papatasi. Here we examine the ability of P. papatasi salivary gland lysate to enhance infection (lesion size and parasite burden) by L. major. In addition, we examine the effects of salivary gland lysate on the immune response to L. major by monitoring the levels of cytokine mRNA from the lymph nodes draining cutaneous lesions. We found that P. papatasi salivary gland lysate dramatically exacerbated lesion development in disease-resistant CBA mice. This exacerbation of disease correlated with inhibition of the production of Thl cytokines and associated factors (IFN-gamma, IL-12, and inducible nitric oxide synthase), but with enhancement of the Th2 cytokine IL-4, whereas no changes in the levels of IL-10 and TGF-beta were noted. Importantly, salivary gland lysate directly up-regulated expression of IL-4 mRNA in mice in the absence of infection with L. major.  相似文献   
102.
This article reports 10 cases of cranial base tumors resected by pre-or retro-auricular intratemporal approach. Among them four were neuronomas, two meningiomas, one malignant giant cell tumor of bone, one osteochondnoma, one parotid mixed neoplasm and one poorly-differentiated squamors cell carcinoma. Total resection in 9 cases and one subtotal resection were performed without operative mortality and serious surgical complications. The surgical management of cranial base tumor and indications for selecting operative approaches were discussed.  相似文献   
103.
Experiments on a torsional oscillator containing a slab of liquid3He of thickness 105 µm and diameter 8.38 mm are described. Normal phase experiments confirm the theory of the oscillator dynamics but an apparent descrase in the measured value of T 2 at lowT casts doubt on the existing slip theory. Measurements for the uniform texture for the A phase give values of s and 44. The s measurements suggest that the A-phase energy gap is enhanced by a factor 1.24 over the BCS value. Distortion of the uniform texture by a magnetic field perpendicular to the slab occurs at a threshold field slightly smaller than predicted. Measurements for fields at different angles to the slab enable accurate values to be deduced for the superfluid density anisotropy and two other viscosity coefficients. The remaining two viscosity coefficients are only poorly determined. Flow alignment of the orbital texture was achieved by increasing the oscillator amplitude. A different texture obtained on some occasions after warming from the B phase was investigated but is not understood.  相似文献   
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Sodium N-[(trimethylamineboryl)-carbonyl]-L-phenylalanine 2 and {N-[(trimethylamineboryl)-carbonyl]-L-phenylalanyl- carbxylato}-bis-{N-[(trimethylaminebryl)-carbonyl]-L-phenylalanine} dicopper (II) 3 were successfully synthesized. The agents blocked L(1210) leukemic cell DNA and RNA syntheses by inhibiting multiple enzyme activities for nucleic acid synthesis, e.g. PRPP amido transferase, IMP dehydrogenase, DNA polymerase alpha, thymidine kinase, and TMP kinase. The copper (II) complex 3 demonstrated improved ability to inhibit L(1210) partially purified DNA topoisomerase II compared to the parent compound while the sodium salt was inactive at 100 muM.  相似文献   
108.
Equilibrium exchange isotherms were determined for the exchange of Cu2+ with NaZSM-5 at varying Cu(Ac)2 concentrations in solutions of constant volume and zeolite weight. At low Cu2+ levels the solid scavenged all the copper ions. When copper could be detected in the equilibrated solutions, overexchange was observed. The extent of overexchange was higher at pH 6 than at pH 4. These results were analyzed in relation to catalytic activity.On leave from the Central Institute for Chemistry, Hungarian Academy of Sciences, H1525 Budapest, Hungary.  相似文献   
109.
The quantitative aspects of the role of interfacial mass-transfer and reaction kinetics in ethoxylation of lauryl alcohol were examined in a batch recirculation reactor. The liquid droplets falling through a gas column were obtained by utilizing a recirculation loop and a set of spray nozzles. The CO2/NaOH reaction was employed to characterize the interfacial area. The alkoxylation reaction was studied at temperatures between 124°C and 171°C, at catalyst levels between 0.09 and 0.50 weight percent and at ethylene oxide partial pressures between 68 kPa and 204 kPa. A model was developed which permits the prediction of reactor performance at various operating conditions. The mass-transfer during free fall dominates the interfacial mass-transfer and the contributions during the drop formation and coalescence stages are small. The rate of ethylene oxide (EO) addition to lauryl alcohol was constant during the batch run, indicating similar activity for the unreacted lauryl alcohol and the lauryl alcohol ethoxylated to varying extents. The rate of ethoxylation is first-order in both catalyst and ethylene oxide concentrations. The liquid-phase reaction kinetics and interfacial mass-transfer occur in series, with kinetics dominating the overall ethoxylation rate. As expected, an increasing role of mass transfer is observed at higher temperatures, and/or higher catalyst concentrations where the kinetic rate becomes significantly high. The intrinsic activation energy for the ethoxylation of lauryl alcohol is 55.2 kJ/mole.  相似文献   
110.
A new application of low-angle laser light scattering has led to a new instrument capable of characterizing the rubber particle size distribution of high-impact polystyrene (HIPS) containing particles as small as 0.1 μ. Rubber particle size distributions of several HIPS resins have been characterized, and the particle size ranking of resins using light scattering parallels the ranking of resins using photomicroscopy. Several solvents have been employed to suspend the HIPS rubber particles for the scattering determination. Swelling of the rubber phase has been found to be relatively insensitive to variations in rubber phase crosslinking when methyl ethyl ketone is used to suspend the rubber particles. Particle swelling in methyl ethyl ketone does not detract from the usefulness of the light scattering method for HIPS rubber particle size characterization.  相似文献   
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