Enhancement of natural killer cell function by titanocenes in mice bearing Ehrlich ascites tumour

In the present work, we studied the effects of two titanocenes, biscyclopentadienyidichlorotitanium IV, (DDCT) and its derivative, biscyclopentadienylditiocianatetitanium IV (BCDT), on the activity of natural killer (NK) cells in Ehrlich ascites tumour (EAT)-bearing BALB/c mice. In order to investigate a more direct effect of these compounds on NK cell function, we performed experiments with severe combined immunodeficiency (SCID) mice, which exhibit a normal NK cell response in the absence of T and B cells. The treatment consisted of intraperitoneal (i.p.) administration of 15 mg/kg/day of DDCT for 2 days or 10 mg/kg/day of BCDT for 3 days. In addition, to verify whether the effects produced by the titanocenes were compound specific or related to a direct antitumour effect, we also investigated the effects of a 3-day treatment with 100 mg/kg of cyclophosphamide cyclophosphamide on NK cell activity. Our results demonstrated that, in BALB/c and SCID mice, NK cell function declined to subnormal levels after inoculation of the tumour. In these animals, although treatment with DDCT and BCDT significantly enhanced NK cell function, only DDCT restored NK cell activity to normal values in all stages studied. Conversely, treatment with cyclophosphamide reduced NK cell function in nontumour bearing SCID mice and was also unable to restore the decreased NK activity of tumour-bearing SCID mice, thus demonstrating that the enhancement of NK cell function by titanocenes is compound specific. The same effect of cyclophosphamide was observed with BALB/c mice. In the present study, the up-modulatory effects of these two compounds on NK cell function reveal a new aspect of the mechanism of antitumoural action of titanocenes. (C) 2003 Elsevier B.V. All rights reserved.

MICROFIBRILS - NEGLECTED COMPONENTS OF PRESSURE-BEARING TENDONS

Some tendons wrap around joints and receive compressive forces besides transferring the tension forces from muscle to bone. These tendons develop a fibrocartilaginous structure which enables them to withstand pressure. This article describes the existence and distribution of microfibrils (or preelastic fibers) in the pressure-bearing tendons of rabbits and dogs by the application of histochemical assays and transmission electron microscopy. Rabbit and dog tendons possess no mature elastic fibers. The rabbit tendon exhibits some response to Weigert's method prior to oxidation which indicates the existence of the so-called elaunin fibers, especially in the pressure zone. Oxidation with peracetic acid or oxone discloses intricate aspects of the oxytalan fiber distribution in both tension and pressure zones of the dog and rabbit tendons. Bundles of 12 nm microfibrils were demonstrated in the rabbit tendon by electron microscopy after fixation in the presence of tannic acid. The existence of preelastic fibers in the pressure-bearing tendons has been neglected and they are assumed to have importance in the microarchitecture of the tissue and in the ability of the tendon to support tension and compression forces.

Associations of spiders of the genus Peucetia (Oxyopidae) with plants bearing glandular hairs

Two common South American species of lynx spiders, Peucetia rubrolineata and P. flava (Oxyopidae), were surveyed on three localities in southeastern Brazil to determine plant choice. Both species were found to be associated with plants bearing glandular trichomes. A literature review and complementary data show that ten Peucetia species are associated with up to 55 plant species bearing glandular trichomes in at least 20 distinct vegetation types (phytophysiognomies) in more than 36 localities in the Neotropical, Neartic, Afrotropical, and Paleartic regions. The main plant families used by the spiders were Solanaceae, Asteraceae, and Melastomataceae. The specialization of the Peucetia species for plants bearing glandular trichomes may have evolved because insects adhered to these sticky structures may be used as prey by the spiders.

The characteristics of a nonlinear vibration neutralizer

This paper concerns an investigation into the use of cubic nonlinearity in a vibration neutralizer to improve its effectiveness. It is assumed that the frequency of the harmonic excitation is well above the resonance frequency of the machine to which the neutralizer is attached, and that the machine acts as a simple mass. It is also assumed that the response of the system is predominantly at the harmonic excitation frequency of the machine. The harmonic balance method is used to analyze the system. It is shown how the nonlinearity has the effect of shifting the resonant peak to a higher frequency away from the tuned frequency of the neutralizer so that the device is robust to mistune. In a linear neutralizer this can only be achieved by adding mass to the neutralizer, so the nonlinearity has a similar effect to that of adding mass. Some characteristic features are highlighted, and the effects of the system parameters on the performance are discussed. It is shown that, for a particular combination of the system parameters, the effect of the nonlinearity is also to increase the bandwidth of the device compared to the linear neutralizer with similar mass and damping. Some approximate expressions are derived, which facilitate insight into the parameters which influence the dynamics of the system. The results are validated by some experimental work. (c) 2012 Elsevier Ltd. All rights reserved.

A joint computational and experimental study of a novel dioxomolybdenum(VI) complex bearing chiral N,N-dimethyllactamide ligand

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Evaluation by Free Vibration Method of Moisture Absorption Effects in Polyamide/Carbon Fiber Laminates

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Gold-bearing iron duricrust in Central Brazil

In the Cuiabá region-State of Mato Grosso, Central Brazil-primary gold mineralization is hosted by two generations of quartz veins in Precambrian metamorphic terrains of the Cuiabá Group. Gold is mined from the veins and mainly from the eluvial horizons that cover the deeply altered basement. In the lodes gold occurs as small particles (less than 1 mm) associated with pyrite and contains up to 5% Ag. Larger particles and nuggets of almost pure gold are found in the iron duricrust which caps the upper levels of the weathering profile. It is difficult to determine the average grade of this kind of deposit but some prospects in the Cuiabá region produce up to 2 g gold per ton of ore. Lateritization is responsible for both the formation of the iron crust and the concentration of gold within the regolith. Under a tropical climate, the supergene alteration of phyllites of the Cuiabá Group has led to the formation of a weathering profile consisting typically of saprolite, mottled clay zone and duricrust, from bottom to top. The duricrust is directly derived form the in situ weathering of phyllites. Geochemical balance calculations indicate that in the transition from the saprolite to the duricrust lateritization has promoted a progressive loss of Si, Al and K, and more than 500% of absolute Fe enrichment. Gold underwent a supergene evolution related to the development of the weathering profile. In the saprolite and mottled clay zone, associated with quartz and oxidized sulfides, gold dissolves as demonstrated by corrosion features at the surface of the particles. The formation of secondary gold in the duricrust is indicated by the larger size of the nuggets, their higher fineness and the close relationship between gold and the neoformed iron oxy-hydroxides. © 1991.

Sulfur and carbon isotopes in scapolite-bearing granulites of the São José do Rio Pardo area, Brazil

Sulfur and carbon isotope compositions of ten scapolites from granulite-facies rocks of the São José do Rio Pardo area, Guaxupé Complex, Brazil, were measured. Scapolite is the primary and major rock-forming mineral in these rocks (up to 40 volume %). The isotopic composition of the sulfate and carbonate group in the scapolite structure has δ34S values of +1.0‰ to +6.7‰, and δ13C values of -14.3‰ to -6.3‰, respectively. The sulfur isotope data may be related to an upper mantle (external) or lower crustal (internal) source for the sulfur, whereas the carbon appears to have been derived from an internal source. Thus, the carbon and sulfur isotope data can be explained without invoking an external (mantle) source. © 1993.

Paracentric inversion involving a NOR-bearing chromosome of rainbow trout (Oncorhyncus mykiss): Electron microscopy studies of the synaptonemal complex

Cytogenetic studies conduced on a sample of 19 specimens of rainbow trout (Oncorhyncus mykiss) showed that 6 presented two chromosomes with a single subterminal AgNOR on the short arms and 13 presented one chromosome with a single subterminal Ag-NOR and a second chromosome with two small subterminal Ag-NORs. Synaptonemal complex studies showed the presence of a pairing failure involving the two lateral elements (LEs) of the NOR-bearing chromosomes only in those specimens with two different NOR-bearing chromosomes, suggesting that the chromosomes with two Ag-NORs originated from a paracentric inversion involving a terminal segment of the original NOR-bearing chromosome. A comparative analysis between three normal and three heterozygous fishes suggest that in the latter group the LEs of the NOR-bearing chromosomes initiate the synaptic process in a more delayed manner, the synapsis develops more quickly, and the nucleolus stays associated with chromosomes for a longer time.

Joint Vibration Analysis in Patients with Articular Inflammation

The study of articular sounds using a computerized system (SonoPAK) in patients with temporomandibular disorders (TMD) of inflammatory origin revealed an increase of vibratory energy when compared to asymptomatic individuals. The following conclusions were reached: 1. The amount of vibratory energy registered in these patients ranged from 8.50 to 57.61 Hz. The major vibrations occurred in the middle of the mandibular opening cycle; 2. The mean vibratory energy measured at less than 300 Hz was between 5.70 and 48.64 Hz and at higher than 300 Hz was between 3.70 and 8.99 Hz; 3. The peak amplitude in the patients with inflammation ranged from 0.35 to 3.96 Pascal and the peak of frequency from 83.20 to 120.20 Hz.

Optimal design of smart structures using bonded piezoelectrics for vibration control

Smart material technology has become an area of increasing interest for the development of lighter and stronger structures which are able to incorporate actuator and sensor capabilities for collocated control. In the design of actively controlled structures, the determination of the actuator locations and the controller gains, is a very important issue. For that purpose, smart material modelling, modal analysis methods, control and optimization techniques are the most important ingredients to be taken into account. The optimization problem to be solved in this context presents two interdependent aspects. The first one is related to the discrete optimal actuator location selection problem, which is solved in this paper using genetic algorithms. The second is represented by a continuous variable optimization problem, through which the control gains are determined using classical techniques. A cantilever Euler-Bernoulli beam is used to illustrate the presented methodology.

The effect of actuator and sensor placement on the active control of rotor unbalance

This paper investigates both theoretically and experimentally the effect of the location and number of sensors and magnetic bearing actuators on both global and local vibration reduction along a rotor using a feedforward control scheme. Theoretical approaches developed for the active control of beams have been shown to be useful as simplified models for the rotor scenario. This paper also introduces the time-domain LMS feedforward control strategy, used widely in the active control of sound and vibration, as an alternative control methodology to the frequency-domain feedforward approaches commonly presented in the literature. Results are presented showing that for any case where the same number of actuators and error sensors are used there can be frequencies at which large increases in vibration away from the error sensors can occur. It is also shown that using a larger number of error sensors than actuators results in better global reduction of vibration but decreased local reduction. Overall, the study demonstrated that an analysis of actuator and sensor locations when feedforward control schemes are used is necessary to ensure that harmful increased vibrations do not occur at frequencies away from rotor-bearing natural frequencies or at points along the rotor not monitored by error sensors.

Morphometric study by image analysis of Ag-stained nucleoli in thyroids bearing proliferating lesions

The Ag-NOR staining technique and image analysis were used to evaluate morphological parameters (area, perimeter and axis ratio) in nucleoli from normal thyroids and from thyroids bearing proliferating lesions (carcinomas, adenomas and hyperplasias). Regions with normal appearance located close to adenomatous and carcinomatous regions, in the thyroid of every patient, were also analyzed for comparison with the respective pathological regions and with normal thyroids. Statistical analysis of data for the nucleolar area and perimeter allowed the separation of adenomas and carcinomas from hyperplasias and normal tissue but not the two components in each of these two groups. However, if we look at the numbers, a sequence of increasing nucleolar mean areas in the order: normal, hyperplasia, adenoma and carcinoma may be observed, indicating the sequence of increasing rRNA requirements in these different kinds of cells. The axis ratio that denotes the nucleolar shape (round or oblong) did not show significant differences among tissues, suggesting that shape is not important in the characterization of these pathologies. Differences in nucleolar areas and perimeter between normal and affected regions from each patient were statistically significant for adenomas and carcinomas. When these normal regions were compared with the normal thyroids, significant differences were not obtained in the three evaluated parameters. The observations and their importance for histopathological diagnosis are discussed.