Inhibition of matrix metalloproteinases attenuates anti-Thy1.1 nephritis

An understanding of the olfactory system of any animal must account for how odor mixtures are perceived and processed. The present experiments apply associationist models to the study of how elements are processed in binary odorant mixtures. Using experimental designs for Proboscis Extension Conditioning of honey bees, I show that learning about a pure odorant element is frequently affected by its occurrence in a mixture with a second odorant. Presence of a background odor when an odorant is associated with sucrose reinforcement decreases the rate and/or asymptotic level of associative strength that accumulates to that odorant. This interaction is in part due to synthetic qualities that arise in sensory transduction and initial processing. In addition, it involves an attention-like processing system like that involved in overshadowing. Therefore, a model that includes representations of the component and configural qualities of odorants in mixtures is needed to provide a more complete account of learning about odor mixtures.     

Reasoning by model: The case of multiple quantification.

A theory of deductive reasoning is presented for a major class of inferences that has not been investigated by psychologists: inferences that depend on multiply-quantified premises (e.g., "None of the Princeton letters is in the same place as any of the Dublin letters"). It is argued that reasoners construct mental models based on their knowledge of the meanings of quantifiers (and other terms, including relational expressions). Three experiments corroborate the model theory's prediction that inferences that require the construction of only 1 model will be easier than those that require more than 1 model. The model theory assumes that the logical properties of quantifiers emerge from their meanings and are not mentally represented in rules of inference. How such a semantic process can occur compositionally (i.e., guided by the syntactic analysis of sentences) is described. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Immunization with meningococcal membrane-bound lipooligosaccharide accelerates granulocyte recovery and enhances lymphocyte proliferation in myelosuppressed mice

Protective effects of detergent-treated outer membrane vesicles (D-OMVs) prepared from the parent group B M986 strain and the nonencapsulated M986-NCV mutant in myelosuppressed mice were investigated in models of experimental septic shock. The effects of D-OMVs on expansion of the myeloid compartment, on spleen cell proliferation to mitogen stimulation, and on cytokines induced during this period were investigated. On 3 consecutive days, mice were injected with 1 microgram/kg of lipooligosaccharide (LOS) or lipopolysaccharide, or 75 micrograms/kg D-OMV followed by a single dose of cyclophosphamide (200 mg/kg) 24 h later. Eight weeks after the last injection, animals were challenged with a combination of galactosamine (400 mg/kg) and live Neisseria meningitidis. More than 90% of control mice died within 24 h when challenged with 10(5) CFU of bacteria. Mice immunized with LOS or D-OMV were rendered neutropenic but were protected against bacterial challenge of at least 10(7) CFU. At different time intervals, peripheral blood samples were obtained to characterize changes in circulating blood cells. The rise in absolute granulocyte numbers occurred 24 h earlier with peak cell counts about 3 times higher than those seen in the placebo groups. Peripheral blood cells from D-OMV-treated animals expressed about twofold more Gr-1 antigen (myeloid surface cell marker) than placebo-treated controls. The proliferative responses to both B and T cells were reduced in all treatment groups due to the effects of cyclophosphamide. D-OMV treatment afforded the greatest protection for mitogen-activated lymphocytes from the lethal effects of cyclophosphamide and also enhanced T and B cell proliferation. Low IL-1 beta levels and increases in serum IL-6 were detected in all treatment groups. In contrast, significant IFN-gamma and IL-3 levels were only detected in D-OMV-treated groups. These results indicate that D-OMVs, which have reduced toxicity, have prophylactic potential in inducing specific cytokines that accelerate granulocyte recovery following cytoreductive therapy by promoting both proliferation and maturation of myeloid precursors as well as augmenting the immune system.     

Expression of matrix metalloproteinases and tissue inhibitors of metalloproteinases in reactive and neoplastic lymphoid cells

We have studied the expression of gelatinase A, gelatinase B, interstitial collagenase, tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 in reactive lymphoid cells, as well as in a series of cell lines derived from neoplasms of B- and T-cell lineage. Using both Northern blot analysis and zymography, gelatinase B activity was detected by zymography in two Burkitt cell lines and in a tonsillar cell suspension, while gelatinase A and interstitial collagenase activities were not detected by either method. TIMP-1 expression was demonstrated by Northern blot analysis in the multipotential neoplastic K-562 cell line, the high grade Burkitt's B-cell lymphoma lines, isolated tonsillar B cells and at low levels in peripheral blood T cells, but was not expressed in any of the neoplastic T-cell lines or isolated peripheral blood B cells. In contrast, TIMP-2 expression was restricted to tissues containing cells of T-cell lineage with high levels being observed in the neoplastic T-cell lines and lower levels in normal peripheral blood T cells and hyperplastic tonsil. Expression of TIMP-1 and TIMP-2 was confirmed at the protein level by reverse zymography and immunofluorescence assays using antihuman TIMP polyclonal antibodies. Expression of gelatinase B by the high grade B-cell Burkitt's lymphoma cell lines is consistent with previous findings in large cell immunoblastic lymphomas and indicates that this enzyme may play an important role in high grade non-Hodgkin's lymphomas. TIMP expression correlated with cell lineage in that TIMP-1 was primarily observed in B cells and TIMP-2 was restricted to T cells.     

Iterative solution to the Gel'Fand-Levitan-Marchenko coupledequations and application to synthesis of fiber gratings

In this paper, we develop an iterative solution to the coupled Gel'Fand-Levitan-Marchenko integral equations. It will be proved that this new technique outstands other methods such as the exact GLM solution or the Fourier method. As one of its many applications, the synthesis of fiber gratings for dispersion equalization will be tackled     

BER impairment due to laser linewidth in OFDM-OOK systems usingdouble-cavity Fabry-Perot demultiplexers

We report on the impact of finite laser linewidth on the bit error rate (BER) performance in directly detected optical frequency-division multiple-access (OFDMA) employing double-cavity Fabry-Perot (FP) filters. Three different double-cavity FP demultiplexers have been considered in this study. Also the laser linewidth impairment on the crosstalk probability mass functions, the crosstalk power penalties and the OFDMA network capacity are calculated. The results demonstrate that, even though these demultiplexing schemes are much superior than single-cavity FP filters for highly coherent sources (laser linewidth lower than a few megahertz), when laser linewidth increases this feature appears to be much less significant due to the severe impairment of the laser linewidth on the BER performance, specially for structures with higher optical filter finesse     

Distributed feedback gain-coupled lasers based on InGaAs quantum-wire arrays

Fabrication and characterization of a current-injected InGaAs-GaAs quantum-wire gain-coupled distributed feedback (DFB) laser operating at 77 K at a wavelength of 923 nm are presented. Threshold current densities in broad area lasers were measured to be as low as 160 A/cm/sup 2/. The side-mode suppression ratio at twice threshold is 35 dB. A 4-/spl mu/m rib waveguide device has a threshold of 14 mA. The patterning process for the second-order DFB grating fabricated with deep UV holography and wet-chemical etching is described.