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121.
OBJECTIVES: To find the incidence of brucellosis, and analyse its epidemiological characteristics and the evolution of the cases recorded in the Sierra de Cádiz Primary Care (PC) Area during 1992. DESIGN: A prospective longitudinal incidence analysis, with a nested study of cases and controls. SETTING: Sierra de Cádiz PC Area. PATIENTS AND OTHER PARTICIPANTS: Cases: members of the cohort who developed the disease. Controls: sample of members of the cohort free of Brucellosis paired for age, gender and town of origin. MEASUREMENTS AND MAIN RESULTS: Incidence was 52.39 per 100,000, 66.27 and 38.20 per 100,000 in men and women, respectively. Highest incidence was at between 15 and 49 years of age (67.70 per 100,000). Cases in the Spring predominated (chi 2 = 16.77, gl = 3, p < 0.05). The most affected professional group was farmers/herders (RR = 4.59, CI 95%, 2.05-10.26). CONCLUSIONS: The Sierra de Cádiz is an area with endemic brucellosis, especially in the districts of Olvera and Ubrique. Its work-related character is clear, in spite of the digestive tract being the main transmission path.  相似文献   
122.
Pleiotrophin (PTN) is a heparin-binding, 18 kDa secretory protein that functions to induce mitogenesis, angiogenesis, differentiation, and transformation in vitro. PTN gene (Ptn) expression is highly regulated during development and is highest at sites in which mitogenesis, angiogenesis, and differentiation are active. In striking contrast, with the exception of the neuron, the Ptn gene is only minimally expressed in adults. We now demonstrate that Ptn gene expression is strikingly upregulated within 3 d in OX42-positive macrophages, astrocytes, and endothelial cells in areas of developing neovasculature after focal cerebral ischemia in adult rat. Ptn gene expression remains upregulated in these same cells and sites 7 and 14 d after ischemic injury. However, expression of the Ptn gene is significantly decreased in cortical neurons 6 and 24 hr after injury and is undetectable in degenerating neurons at day 3. Neurons in contralateral cortex continue to express Ptn in levels equal to control, uninjured brain. It is suggested that PTN may have a vital role in neovascular formation in postischemic brain and that postischemic brain is an important model in which to analyze sequential gene expression in developing neovasculature. In contrast, Ptn gene expression in injured neurons destined not to recover is strikingly reduced, and potentially its absence may contribute to the failure of the neuron to survive.  相似文献   
123.
We previously demonstrated that macrophages isolated from mice fed gamma-linolenic acid (GLA)-enriched diets reduce vascular smooth muscle cell (SMC) proliferation in a cyclooxygenase-dependent fashion and may therefore favorably modulate the atherogenic process. The present study was conducted to elucidate the mechanism(s) by which dietary GLA influences the ability of macrophages to modulate SMC growth programs. Resident peritoneal macrophages were isolated from C57BL/6 female mice fed diets containing variable GLA compositions at 10% (wt/wt), treated with various antibodies and co-cultured with cycling naive vascular SMC isolated from nonpurified diet-fed mice. Smooth muscle cell proliferation and intracellular cAMP levels were measured after co-culture. In parallel experiments, cycling naive vascular SMC isolated from nonpurified diet-fed mice were dosed with exogenous prostaglandin E1 (PGE1 ) for various periods and challenged with cycloheximide for 4 h (8-12 h after PGE1 addition), and intracellular cAMP levels were measured at various time points. Macrophages isolated from mice fed GLA-enriched dietary oils significantly reduced SMC proliferation in co-culture compared with controls (macrophages from mice fed a corn oil diet containing no GLA). Anti-PGE1 antiserum treatment (1:50 or 1:100) blocked the ability of GLA-enriched macrophages to down-regulate SMC proliferation, a response reversed by exogenous PGE1 treatment. Macrophages isolated from mice fed GLA-enriched dietary oils elevated SMC intracellular cAMP levels in a biphasic fashion. In addition, exogenous PGE1 (1 nmol/L to 10 micromol/L) exerted a similar biphasic cAMP response in SMC, and the second phase of cAMP elevation was antagonized by cycloheximide. In conclusion, dietary GLA enhances mouse macrophage-derived prostaglandin E1, which inhibits vascular SMC proliferation.  相似文献   
124.
125.
The preincubation of synaptosomes with nanomolar concentrations of ganglioside GM1 was shown to protect Ca(2+)-dependent and Ca(2+)-independent cyclic nucleotide phosphodiesterase from inactivation caused by lipid peroxidation (LPO) induction. Thus, Ca(2+)-dependent phosphodiesterase activity decreased to approximately 34% of the initial value following 30 min of LPO induction, but it constituted more than 60% of the control activity if synaptosomes were preincubated with 10(-8)M GM1, the difference being statistically significant. 10(-6)M alpha-tocopherol had a similar effect. As far as the lipid matrix is concerned, gangliosides were found to prevent to a great extent malonic dialdehyde (MDA) accumulation and to protect polyenoic fatty acids from oxidative destruction. The ability of gangliosides to protect phosphodiesterase from inactivation caused by LPO induction appears to be owing not only to the inhibition of the accumulation of LPO products, but to the direct activation of the enzyme as well, 10(-7) M of ganglioside GM1 having the maximal activating effect. In contrast to alpha-tocopherol and other antioxidants reacting directly with free radicals, the inhibitory effect of gangliosides appears to be mediated by signal transduction systems.  相似文献   
126.
A 10-year-old left-handed girl with a developmental stutter and agenesis of the corpus callosum with associated hydrocephalus ceased stuttering immediately upon initiation of steroid therapy for colitis. Steroid taper resulted in a recurrence of the stutter and resumption for treatment of recrudescent colitis caused its disappearance again. Baseline agenesis of the corpus callosum with hydrocephalus and the patient's course in the face of the known effects of steroids on white matter lend support to the hypothesis that stuttering reflects anomalous dominance and/or atypical interhemispheric connectivity, as evidenced by the fact that presumed alterations of white matter tracts affected speech rhythms/stuttering.  相似文献   
127.
We prepared three new poly(9,9-dihexylfluorene) derivatives (P1–P3) containing kinked aromatic triazole (triphenyl-1,2,4-triazole derivative) via Suzuki coupling polymerization. These copolymers were soluble in common organic solvents and showed high decomposition temperatures (Td = 416–454 °C). The optical and electrochemical properties of P1–P3 were compared with poly(9,9-dihexylfluorene) (PFO) and P4 and P5 in which the linkages of the aromatic triazole were different. After introducing the triazole units, absorption spectra showed blue shift (388 nm → 372 nm) due to reduced conjugation, but PL spectra remained almost unchanged (417–418 nm). The linkages of triazole with fluorene segments in P1–P5 were different: (1) fluorene segments linked with triazole through a kinked angle (P1 and P2), (2) triazole as a branch unit (P3) and as terminal groups (P4), (3) fluorene segments linked with triazole in a linear way (P5). As estimated from semi-empirical MNDO calculation, two twisted conformations (ca. 90° each) exist between triazole core and fluorene groups. These kinked conformation and twisted structure increased the PL efficiency (ΦPL = 0.60–0.73, ΦPL = 0.58 for PFO) and partially inhibited annealing-induced excimer formation. From cyclic voltammetric results, P1–P3 exhibited better electron affinity (LUMO: −2.75 to −2.82 eV) than PFO (LUMO: −2.52 eV).  相似文献   
128.
The timetabling problem at universities is an NP-hard problem concerned with instructor assignments and class scheduling under multiple constraints and limited resources. A novel meta-heuristic algorithm that is based on the principles of particle swarm optimization (PSO) is proposed for course scheduling problem. The algorithm includes some features: designing an ‘absolute position value’ representation for the particle; allowing instructors that they are willing to lecture based on flexible preferences, such as their preferred days and time periods, the maximum number of teaching-free time periods and the lecturing format (consecutive time periods or separated into different time periods); and employing a repair process for all infeasible timetables. Furthermore, in the original PSO algorithm, particles search solutions in a continuous solution space. Since the solution space of the course scheduling problem is discrete, a local search mechanism is incorporated into the proposed PSO in order to explore a better solution improvement. The algorithms were tested using the timetabling data from a typical university in Taiwan. The experimental results demonstrate that the proposed hybrid algorithm yields an efficient solution with an optimal satisfaction of course scheduling for instructors and class scheduling arrangements. This hybrid algorithm also outperforms the genetic algorithm proposed in the literature.  相似文献   
129.
Effect of quadratic radial phase variation in the plane of the aperture on Fraunhofer diffraction of Laguerre–Gauss vortex beams by a slit is studied experimentally. For slit positions near the incident beam waist, its effect is to shear the diffraction pattern relative to that at the waist. The magnitude and sense of shear depend on the topological charge and slit location relative to the incident beam waist. For slit positions far from the waist, the diffraction pattern evolves to be significantly different and is dominated by two strong peaks. A closed form analytical expression for the diffraction pattern is presented, which reproduces experimental results quite well for all slit positions.  相似文献   
130.
Most publications in shop scheduling area focus on the static scheduling problems and seldom take into account the dynamic disturbances such as machine breakdown or new job arrivals. Motivated by the computational complexity of the scheduling problems, genetic algorithms (GAs) have been applied to improve both the efficiency and the effectiveness for NP-hard optimization problems. However, a pure GA-based approach tends to generate illegal schedules due to the crossover and the mutation operators. It is often the case that the gene expression or the genetic operators need to be specially tailored to fit the problem domain or some other schemes may be combined to solve the scheduling problems. This study presents a GA-based approach combined with a feasible energy function for multiprocessor scheduling problems with resource and timing constraints in dynamic real-time scheduling. Moreover, an easy-understood genotype is designed to generate legal schedules. The results of the experiments demonstrate that the proposed approach performs rapid convergence to address its applicability and generate good-quality schedules.  相似文献   
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