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Many strategies, including those based on genetically modified Mesenchymal Stromal Cells (MSCs), have been developed in recent years in order to obtain high concentrations of anticancer drugs effective on tumor mass. In previous studies, we showed that human and murine bone marrow-derived MSCs (BM-MSCs) and human skin-derived stromal fibroblasts (hSDFs) acquired strong anti-tumor capacity, both in vitroand in vivo, once primed with Paclitaxel (PTX). In this report we investigate whether adipose tissue-derived MSCs (AT-MSCs) behave similarly to BM-MSCs in their uptake and release of PTX in sufficient amounts to inhibit tumor proliferation in vitro. According to a standardized procedure, PTX primed AT-MSCs (AT-MSCsPTX) were washed and then subcultured to harvest their conditioned medium, which was then tested to evaluate its in vitroanti-tumor potential. We observed that AT-MSCsPTX were able to uptake PTX and release it in a time-dependent manner and that the released drug was active in vitroagainst proliferation of leukemia, anaplastic osteosarcoma, prostatic carcinoma and neuroblastoma cell lines. These data confirm that AT-MSCs, as well as BM-MSCs, can be loaded in vitrowith anti-cancer drugs. While the harvesting of BM-MSCs requires invasive procedures, AT-MSCs can be prepared from fat samples taken with little patient discomfort. For this reason, this source of stromal cells represents an important alternative to BM-MSCs in developing new tools for carrying and delivering anti-cancer drugs into tumor microenvironments.

To verify whether development of cognitive skills and peer acceptance are necessarily linked, 212 students of low socioeconomic status in the first, second, and third grades of a public school in Brazil were studied. A sociometric evaluation of peer group acceptance in play and study situations was conducted. The cognitive tasks were the mental imaging and conservation of mass and length (operative casks) as well as location of dice and equidistancing arrangements (creation of possibilities tasks). Analysis showed the children identified as desirable study companions had highly developed general cognitive abilities, and those chosen as desirable for both study and play not only had highly developed general cognitive abilities but also highly developed operativeness. Children who were socially isolated, however, had even higher mean cognitive assessment score in relation to both creation of possibilities and general cognitive development than did those with ratings of negative or positive salience.

The labyrinth seal flow-induced forces have been identified as one of the causes of rotordynamic instabilities in the recent literature. The eccentricity of the rotor center relative to the seal center introduces asymmetry in the seal clearance flow causing circumferential variation of the pressure in seal cavities. Experimentally-measured seal cavity pressure distributions for different rotor eccentricities are presented in this paper. Resultant seal forces obtained by integrating the circumferential pressures over the rotor surface are presented as a function of rotor eccentricity. The experimental results are also used to validate the analytically predicted seal pressure distributions and forces.

Aeroelastic interaction in turbomachinery is of prime interest to opertors, designers, and aeroelasticans. Operation at off-design conditions may promote blade stall; eventually the stall pattern will propagate around the blade annulus. The unsteady periodic nature of propagating stall will force blade vibration and blade flutter may occur if the stall propagation frequency is entrained by the blade natural frequency. In this work a computational scheme based on the vortex method is used to simulate the flow over a linear cascade of airfoils. The viscous effect is confined to a thin layer, which determines the separation points on the airfoil surfaces. The preliminary structural model is a two-dimensional characteristic section with a single degree of freedom in either bending or torsion. A study of the relationship between the stall propagation frequency and the blade natural frequency has been conducted. The study shows that entrainment, or frequency synchronization, occurs, resulting in pure torsional flutter over a certain interval of reduced frequency. A severe blade torsional amplitude (of order 20 deg) has been computed in the entrainment region, reaching its largest value in the center of the interval. However, in practice, compressor blades will not sustain this vibration and blade failure may occur before reaching such a large amplitude. Outside the entrainment interval the stall propagation is shown to be independent of the blade natural frequency. In addition, computational results show that there is no entrainment in the pure bending mode. Rather, “de-entrainment” occurs with similar flow conditions and similar stall frequencies, resulting in blade buffeting in pure bending.

The electron temperature of a large diameter (8 cm)Qmachine has been increased by a factor of 3 by electron cyclotron resonance heating. Using this technique we have eperimentally studied the effect of electron temperature on coherent flute modes driven by a strong radial electric field. We have found a strong stabilizing effect, as shown by the relationship between the threshold voltage required to excite the instability and the electron temperature. In fact the threshold seems to be proportional to a positive power of temperature. La temperatura degli elettroni di una macchinaQdi grande diametro è stata aumentata di un fattore 3 sfruttando la risonanza ciclotronica degli elettroni. Mediante questa tecnica si è studiato sperimentalmente l’effetto della temperatura elettronica sulla stabilità dei modi di oscillazione generati da un intenso campo elettrico radiale. Si è trovato un forte effetto stabilizzante, come si vede dalla relazione fra la tensione di soglia necessaria per eccitare tali instabilità e la temperatura elettronica. Infatti la soglia risulta proporzionale ad una potenza positiva della temperatura. Электронная температураQ-мащины больщого диаметра (8 см) была увеличена в три раэа, испольэуя злектронный циклотронный реэонанс. Испольэуя зту технику, мы иэучили влияние злектронной температуры на моды осцилляций, обраэованных сильным радиальным злектрическим полем. Экспери-ментально было определено соотнощение между пороговым нап ряжением, тре-буемым для воэбуждения неустойчивости, и температурой.

Using reasonable assumptions for turbomachinery efficiencies and heat exchanger effectivenesses, the Coefficient of Performance (COP) and Specific Heating Effect (SHE) of the regenerated and unregenerated cycles are computed and optimized. Only heating data are presented and both open and closed cycles are considered. An effort is made to indicate those cases where (the working fluid being air) the cycle may be appropriately open to combine the heating function with ventilation. When driven by an appropriately small direct Brayton cycle prime mover, the total potential for a new and widespread gas turbine application of literally millions of units becomes defined.

The labyrinth seal flow-induced forces have been identified as one of the causes of rotordynamic instabilities in the recent literature. The eccentricity of the rotor center relative to the seal center introduces asymmetry in the seal clearance flow causing circumferential variation of the pressure in seal cavities. Experimentally-measured seal cavity pressure distributions for different rotor eccentricities are presented in this paper. Resultant seal forces obtained by integrating the circumferential pressures over the rotor surface are presented as a function of rotor eccentricity. The experimental results are also used to validate the analytically predicted seal pressure distributions and forces.

A numerical simulation of propagating stall in a linear cascade of airfoils at high Reynolds numbers is conducted using a vortex method which was first developed by Spalart [7] for this problem. In this approach, the vorticity is discretized into a large collection of vortex blobs whose motion is tracked in time by the use of a well-known vortex tracing algorithm based on the Euler equation. The near-wall effects of viscosity are accounted for by the creation of discrete vortex sheets at the boundaries of the airfoils consistent with the no-slip condition. These boundary vortices are then released into the flow field downstream of the separation points which are obtained from a boundary-layer routine. Calculations are presented for a variety of flow geometries. It is demonstrated that (for a given cascade of airfoils, disturbance wavelength, and stagger angle) several different flow regimes are obtained: Attached flow at lower angles of attack and a chaotic deep stall configuration at larger angles of attack with a narrow intermediate range of such angles where propagating stall occurs. The physical characteristics of this propagating stall are parameterized and a quantitative study of the effects of camber and imposed wavelength is conducted. Comparisons are made with previous theoretical and experimental studies.

Turbomachine blades on spinning and precessing rotors experience gyroscopically induced instabilities and forcing. With vehicle-mounted turbomachines, either constant or harmonic precession occurs, depending on vehicle or mount motion. Responses of uniform cantilever beams at arbitrary stagger, subjected to the noted rotor motion, are predicted in both self-excited and forced-excitation modes taking into account Coriolis acceleration.

The antibiotic vancomycin is often used in clinical therapy against multiple antibiotic‐resistant bacteria. Twenty strains of enterococci, either Enterococcus faeciumor Ent. faecalis, isolated from different cheeses were tested for resistance to vancomycin in liquid medium. Minimum inhibitory concentration (MIC) values ranged from less than 1 to 4 μg ml−1. A 399 bp intragenic fragment of the vanA gene was not observed after amplification of total DNA of the strains. It seems, therefore, that resistance to vancomycin, which is a common trait for enterococci of nosocomial origin, is not widespread among dairy isolates.

The “time marching” technique is successfully applied to the numerical computation of the nonstationary aerodynamics of a flat plate cascade for compressible flow of either subsonic or supersonic nature. The unsteady perturbation amplitudes of fluid properties are used as the dependent variables so that the computational domain can be reduced to a two-dimensional channel guided by two adjacent blades for any interblade phase angle. A new method of handling the boundary condition is developed in which the order of accuracy for the boundary points will be the same as the interior points. The wake region behind the trailing edge of each blade is treated as a “slip plane” as done in two-dimensional steady state supersonic flow. Results are in good agreement with existing analytical solutions.

An analytical method for predicting the perturbed aerodynamic reactions of a harmonically oscillating flat plate airfoil with time dependent point of separation is presented. It is shown that this method in conjunction with an empirical knowledge of the time history of the separation point can predict stall-flutter. Numerical results are presented and compared with existing theoretical and experimental results with special emphasis on torsional mode of oscillation.

Aeroelastic interaction in turbomachinery is of prime interest to opertors, designers, and aeroelasticans. Operation at off-design conditions may promote blade stall; eventually the stall pattern will propagate around the blade annulus. The unsteady periodic nature of propagating stall will force blade vibration and blade flutter may occur if the stall propagation frequency is entrained by the blade natural frequency. In this work a computational scheme based on the vortex method is used to simulate the flow over a linear cascade of airfoils. The viscous effect is confined to a thin layer, which determines the separation points on the airfoil surfaces. The preliminary structural model is a two-dimensional characteristic section with a single degree of freedom in either bending or torsion. A study of the relationship between the stall propagation frequency and the blade natural frequency has been conducted. The study shows that entrainment, or frequency synchronization, occurs, resulting in pure torsional flutter over a certain interval of reduced frequency. A severe blade torsional amplitude (of order 20 deg) has been computed in the entrainment region, reaching its largest value in the center of the interval. However, in practice, compressor blades will not sustain this vibration and blade failure may occur before reaching such a large amplitude. Outside the entrainment interval the stall propagation is shown to be independent of the blade natural frequency. In addition, computational results show that there is no entrainment in the pure bending mode. Rather, “de-entrainment” occurs with similar flow conditions and similar stall frequencies, resulting in blade buffeting in pure bending.

The Saint Venant torsion problem is solved for a region bounded by two circular arcs forming a crescent. The region is conformally transformed to an infinite strip and the stress function is obtained by Fourier integral. Subsequent quadratures for evaluation of the torsion constant are obtained explicitly with the exception of a single infinite integral which may easily be evaluated numerically. Some values of the torsion constant are given, and an approximate formula valid for small “camber” is presented.

The important blade-excitation phenomena in turbomachines are reviewed with respect to the theory extant in the literature and with respect to typical experimental results. The mechanisms of flutter, forced excitation, and rotating stall are discussed broadly and the importance of subharmonic resonance in turbine blades is introduced. Finally, general topics worthy of furthur consideration are enumerated and avenues for future research are delineated.