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Das Adenokarzinom der Prostata ist gegenwartig mit annahernd 100000 Neuerkrankungen pro Jahr und 30000 Todesfallen der am weitesten verbreitete Krebs unter amerikanischen Mannern. Durch eine Anderung des Konzeptes der chirurgischen Behandlung bei dieser Erkrankung sind bis zu 30% der am Prostatakarzinom erkrankten Patienten potentielle Kanditaten fur eine definitive Operation, wie z. B. die radikale Prostatektomie.

Understanding the effects of blood on poly(urethanes) requires a knowledge of the interactions between the polymer and individual blood components. This study examines the calcium-poly(urethane) interaction. Calcification has been associated with a loss of mechanical properties leading to premature failure of polymer implants. Using tensile testing, dynamic mechanical testing, differential scanning calorimetry and infrared spectroscopy, this study observed the changes in structure and properties of a poly(ether urethane) when calcium is blended with it. It is shown that the polyether soft segment may serve as an initiation site for calcification, leading to premature failure.

Relaxations α et β d'une variete de polyethylenes etudiees en detail par des methodes mecaniques dynamiques a basse frequence

This paper addresses the problem of steady deflection of a very flexible spinning disk due to transverse loads that are fixed in space. We first approach this problem within the context of membrane theory. The membrane differential operator is classified and shown to be hyperbolic in the outer region and elliptic in the inner portion. The characteristics are studied and qualitatively compared with some experimentally observed standing waves in the outer region of a membrane-like disk. The eigenvalue problem is examined and the membrane operator is found to be singular. We therefore conclude that the problem of interest cannot be solved within the context of membrane theory. Finally, the problem is formulated with bending stiffness retained. The concentrated load problem is solved by use of a Fourier series expansion in the angular direction in conjunction with a numerical solution for the radial modes. Graphical results are presented for various values of the stiffness parameter and load location.

The theory of large inextensional deformation of cantilevered plates, as recently put forth by Simmonds and Libai, is extended to include orthotropic plates and plates with distributed loading. The bending rigidities of the orthotropic plate are calculated in terms of known material constants, and as functions of the single curvilinear coordinate employed in the theory. The constitutive relationships are then reformulated and the equilibrium equations transformed accordingly. The distributed loading that enters into the local equilibrium equations of the Simmonds-Libai theory is, in this paper, carried through to the overall equilibrium equations.

Long, thin, open section beams and corrugated panels undergo a cross section flattening when bent longitudinally. This leads to a “soft” nonlinear moment-curvature response and geometrical instability. The problem is analyzed by means of a closed, convergent sequence of algebraic and integral equations which are tractable on modern microcomputers. The shape of the cross section is unrestricted, save that it be thin, symmetrical, and not self-penetrating. Results for circular section and angle section beams are obtained and compared with the existing literature. Example results for a wide, corrugated panel are also obtained. Bifurcations in the deformed cross section are found to occur.

Due to a complicated spectrum of natural modes of vibration, flexible spinning disks are very sensitive to transverse loading, and deflections have been difficult to compute. Developed in this paper is an efficient technique for determining the forced response from space fixed loads. Using an eigenfunction expansion, we are able to identify, a priori, those modes which are most important to the overall response. By ignoring unimportant modes we are able to coverge upon a numerical solution with a speed that is orders of magnitude faster than other commonly used techniques.

SUMMARY A mastitis control program carried out in 35 commercial dairy heards over three years increased the milk produced by 343 kg per cow***per year and the amount of butterfat by 15.8 kg per cow per year, giving a net benefits of $16.10 per cow per year by the end of the third year. The net benefit Is considerat***y understated since benefits other than the increase in milk production were not quantified. The overall disposal rate of 33 herds showed a drop from 19.3% in year 1 to 13.6% In year 3. An analysis of culling records showed that as the severity of mastitis Increased so did cow age.

A numerical and experimental study of the Simmonds-Libai (1979) plate theory is presented in this paper. This concerns the large, inextensional, noncylindrical bending of cantilevered plates.

A new technique, based on fluid modulation in a low‐pressure fast‐flow apparatus, has been used to measure the vibration‐to‐translation relaxation rates of N2 and CO2(001) by alkali metal atoms. Basically, the technique is to fluid‐modulate trace amounts of CO2 which are added to a fast‐flowing alkali metal‐active N2 mixture. The extremely fast resonant collisional exchange between N2(ν=1) and CO2(001) inverts the CO2(001) level, as in a fluid mixing laser, which is then probed with a CO2 laser. By measuring the optical gain with and without the alkali metal, the vibrational relaxation rates can be determined. This method enables gain changes as small as 0.1% to be measured. The effective rate, keff=kN2–M +0.914(XCO2/XN2) kCO2–M, has been determined for XCO2/XN2=0.071 and M = Li, Na, K, and Cs: Li, keff=1500±500 torr−1 · sec−1; Na, keff=1400±200; K, keff=4600±1000; Cs, keff=7900±2000. In the case of Na, XCO2 was also varied on order to determine the individual rates: kN2–Na=920±100 torr−1 · sec−1 and kCO2...

We have purified coated vesicles from rat liver by differential ultracentrifugation. Electron micrographs of these preparations reveal only the polyhedral structures typical of coated vesicles. SDS PAGE of the coated vesicle preparation followed by Coomassie Blue staining of proteins reveals a protein composition also typical of coated vesicles. We determined that these rat liver coated vesicles possess a latent insulin binding capability. That is, little if any specific binding of 125I-insulin to coated vesicles is observed in the absence of detergent. However, coated vesicles treated with the detergent octyl glucoside exhibit a substantial specific 125I-insulin binding capacity. We visualized the insulin binding structure of coated vesicles by cross-linking 125I-insulin to detergent-solubilized coated vesicles using the bifunctional reagent disuccinimidyl suberate followed by electrophoresis and autoradiography. The receptor structure thus identified is identical to that of the high-affinity insulin receptor present in a variety of tissues. We isolated liver coated vesicles from rats which had received injections of 125I-insulin in the hepatic portal vein. We found that insulin administered in this fashion was rapidly and specifically taken up by liver coated vesicles. Taken together, these data are compatible with a functional role for coated vesicles in the receptor-mediated endocytosis of insulin.

A study is made of steady and non-steady flow through a carburettor. A model is presented in which the carburettor is represented by an adiabatic pressure loss at a discontinuity in the intake system of an engine. It is shown that this simple model gives excellent predictions of the pressure-time development in the intake system except at small throttle openings where there is some error in the peak amplitude. Mass flow and trapped mass predictions are excellent.

The steady state response of a cantilevered rotor with skew and mass unbalances is studied, with special attention to the effects due to skew. A disk misaligned with its drive shaft receives active gyroscopic moments which force pitch changes in the disk, much as mass unbalance centrifugal forces induce disk translation. These active gyroscopic moments affect the rotor in ways unpredicted by passive gryoscopics; that is to say the moments acting on a perfectly aligned disk which changes pitch solely due to its precession. Under the combined influences of disk skew and mass unbalance the precessing rotor exhibits an unconventional phase lag response, and it need not be in line with the mass unbalance at low spin rates. This can significantly alter rotor balancing procedures. Rotor critical speeds are studied for their number and severity, with results presented in a compact nondimensional form.

We examined several factors for their effects on the serological reactivity of Legionella antigens used for direct or indirect fluorescent-antibody tests. These factors included media, methods of killing, strain differences, and the nature of the reactivity with diverse human sera. The maximum serological reactivities were obtained with charcoal-yeast extract agar; the relative antigenicity of cells grown on a chemically defined medium could be fourfold less than those grown on the charcoal-yeast extract agar. Cells grown at 25 degrees C showed only small antigenic differences from those grown at 35 degrees C but had better morphological and staining characteristics. Cells killed by 1% Formalin or 37% Formalin vapors showed a 20% less relative antigenicity than those killed by heat, but their cell walls stained more clearly and they had fewer aberrations. As tested with several human sera, cells of Philadelphia 1 showed great variation in relative antigenicity with changes in media or methods of preparation; Bellingham 1 was quite stable under these same conditions. The data suggest that Bellingham 1 had serogroup 1-specific antigens, reactive with human sera, which were not present in Philadelphia 1.

A solid-phase immunofluorometric assay was used to qualitatively characterize and precisely measure human immunoglobulin class-specific antibody responses in legionellosis. Stable antigen preparations consisted of cells grown at 25 degrees C that were killed, fixed with Formalin vapors, washed, and lyophilized. Working-curve material consisted of dilutions of selected convalescent sera. Linear regressions of logit transformations of relative fluorescence intensities versus the logarithm of the relative concentrations of sera were determined to give immunoglobulin class-specific antibody levels from uninfected and infected individuals. Each fluorescence intensity obtained with immunoglobulin class-specific antibody was converted to a multiple of the median fluorescence intensity obtained with sera from uninfected individuals. A presumptive-positive acute-phase legionellosis serum was defined for each immunoglobulin class by a multiple of the normal median fluorescence intensity that was greater than the multiple of the normal median from approximately 97% of the uninfected population.

A longitudinal bending moment applied to a thin, open section beam induces limit point buckling, due to a second-order effect that flattens the leaves of the cross section. It is shown here, for the case of a circular cross section, that the leaves themselves may exhibit multiple equilibrium configurations. Thus, the postbuckling behavior of the beam is not uniquely defined, and perturbations may shift the system to an unexpected loading path. In this paper, the various equilibrium configurations are examined and judged for stability. A “perfect” bifurcating geometry is identified, and a form of imperfection sensitivity is observed.

The aversive and immunosuppressive effects of cyclophosphamide (CY, 250 mg/kg IP), an unconditioned stimulus (UCS), were paired with the presentation of a novel saccharine flavored drinking solution (SAC), a conditioned stimulus (CS), in female Balb/c mice. The objective was to determine the temporal relationship between presentation of the CS (SAC) and immunization with sheep red blood cell (SRBCs), a T-cell dependent antigen, and type III pneumococcal polysaccharide (S3), a T-cell independent antigen, on subsequent antibody responses. Reexposure to the CS or UCS occurred on days -4, -2, 0, +2, or +4 relative to immunization. Primary antibody responses in each group were measured six days following immunization. A strong association between the CS and the UCS developed, producing flavor aversions as evidenced by decreased SAC consumption. CY administration by itself consistently suppressed both types of antibody responses. CS presentation (i.e., SAC) had no significant effect on anti-S3 antibody response. However, the anti-SRBC response was significantly depressed following CS exposure. Exposure to the CS only on days -4 or +2 relative to immunization resulted in statistically significant suppression of antibody response to SRBC's while exposure on days -2, 0, and +4 resulted in anti-SRBC antibody suppression that did not reach significance. These results support the hypothesis that conditioning of antibody responses is relatively specific for T-cell dependent antigens, and that the timing of CS presentation relative to immunization is important in conditioning a suppression of antibody responses.

A comparison is made of experimental results and predictions of performance and emissions from a multi-cylinder spark ignition engine over a range of air-fuel ratios and two throttle settings. The results showed that a simplified two zone combustion model, a seven reaction scheme for nitric oxide formation, a partial freezing model for carbon monoxide and the inclusion of chemical reactions and variable specific heat along the pathlines in the wave equations gave good agreement with the measurements at the common pipe junction and exhaust outlet, but due to cyclic dispersion and maldistribution of fuel between cylinders the predictions of the emissions in the exhaust manifold adjacent to the cylinder were not so good. The predicted air flow and indicated power agreed well with experiment.

Semiconducting organometallic films such as copper tetracyanoquinodimethan (CuTCNQ) have been observed to switch between two stable states when exposed to optical radiation. Observations of switching between two states in these films have been made by Raman spectroscopic methods and direct observation of electrical resistance changes. Line or pattern generation is observed for exposure above certain threshold levels. These effects are observed in a wide range of Cu and Ag organometallic compounds. Optical switching in films such as copper and silver tetra cyanoquinodimethan (CuTCNQ and AgTCNQ) can be erased using CO2 laser radiation. Results on the wavelength and irradiance dependence of the optical switching threshold are also presented and interpreted in light of proposed switching mechanisms in these organic materials.

Semi-insulating chromium-doped GaAs was implanted with 100 keV Be ions to fluences of 5 × 1013 and 1 × 1015 ions/cm2. Specimens were annealed at 800°C for thirty minutes. Beryllium atomic concentration profiles, as determined by secondary ion mass spectrometry (SIMS), were compared to the defect density profiles obtained from transmission electron stereomicroscopy techniques for the annealed samples. A major redistribution of Be was observed compared to the as-implanted distribution after annealing at the higher fluence, whereas only a slight redistribution of Be occurred for the lower fluence. A major difference in the defect density profiles was observed with the fluences used for this study in the region where the annealed specimens were compared. The distribution of defects throughout the implanted-annealed layer was examined in GaAs annealed after implantation with the higher fluence using sectioned specimens. The relationships between the atomic Be concentration profile, the defect density profile, and the distribution of some specific defects were compared in these sectioned layers. The distribution and size of defects appear to be directly influenced by the Be concentration and its associated implantation induced damage.

The sodium chemiluminescence has been studied in low‐pressure diffusion flames involving Na–N2O and Na–N2O+CO in a helium diluent. In the Na+N2O system, only the Na(3p) level is excited and a lower limit to the photon yield was determined to be ∼3×10−4. Two possible excitation mechanisms are proposed to explain the Na emission. Sodium particles were observed in the flow emanating from the sodium source and the implications of these particles on the measurements is discussed. In the Na‐catalyzed N2O+CO system most of the emission is from Na(3p), although higher Na levels are populated and the distribution is statistical; the photon yield was determined to be ∼0.02. This low value for the photon yield implies that the direct production of electronically excited sodium followed by E–V transfer is not responsible for the vibrational pumping mechanism in the Na–N2O+CO chemical laser.

A basic multistage decomposition strategy for design optimization is described. Resolution of the independent variable vector is accompanied by a decomposition of the optimization problem equation system into sets of modular components and an integrating system component. The optimization subproblem of each modular component set must be explicitly solvable, and specifically the method of optimal design is used. Techniques are developed for handling interactions between the modular component sets. The integrating system component is the basis of control for an automated optimal design search process of reduced dimensionality. An example illustrates application of the developed algorithm.

Studied here is the stability of thin, rectangular, orthotropic plates which are in a state of tension and twist. A transfer matrix method is used to obtain numerical solutions to the linearized von Karman plate equations, and to determine critical angles of twist per unit length which buckle the plate. Results are presented, in a compact nondimensional form, for a range of material, geometric and loading parameters. It is found that orthotropism significantly affects the stability of the plate.

A model is presented to simulate the power cycle and gas exchange process in a crankcase-compression two-stroke spark-ignition engine which includes intake and exhaust systems. Chemical equilibrium and a two-zone combustion model with a spherical flame front are assumed for the power cycle and generalized non-steady gas dynamic expressions, including variable composition, variable specific heats, friction and heat transfer, are assumed for the gas exchange process in the intake and exhaust systems. For the scavenge process in the cylinder, a thermal mixing model is used to calculate the pressure changes. Experiments with a small high-speed engine showed that the model gave good predictions of the pressure changes during the gas exchange process and the air flow rate. The power predictions followed the experimental trend, but the quantitative results were not so good as the air flow predictions. Despite the limitations of the power predictions, the method offers the designer a tool for improving the performance of the crankcase-compression engine.

The steady deflection of a transversely loaded, extremely flexible, spinning disk is studied. Membrane theory is used to predict the shapes and locations of waves that dominate the response. It is found that waves in disconnected regions are possible. Some results are presented to show how disk stiffness moderates the membrane waves, the most important result being an upper bound on the highest ordered wave of significant amplitude. A hybrid system of differential equations and boundary conditions is developed to replace the pure membrane formulation that is singular, and the full fourth-order plate formulation that is numerically sensitive. The hybrid formulation retains the salient features of the flexible disk response and facilitates calculations for very small disk stiffnesses.

SYNOPSIS A computer controlled diesel engine test-bed is described. The system is capable of excursions into regions of very low air-fuel ratio operation without damage to the engine; this enables the engine “steady-state” characteristics to be measured for off-design operating conditions. A computer-based data acquisition system was developed to acquire test-bed results under engine transient operating conditions. An analogue computer model of the engine was constructed using the steady-state characteristics of the engine as obtained from on- and off-design. This model operated in real-time and was suitable for both studies of engine control systems and the testing of control hardware. Results obtained from the test-bed and the model are compared. It is shown that good agreement can be achieved by minor modifications to the model based on steady state results.

A homologous series of copolyether–urethane–ureas were synthesized with polypropylene glycol segments having molecular weights of approximately 200, 400, 700, 1000, 2000, and 3000. These copolymers were characterized using tensile measurements and dynamic mechanical spectroscopy. The dynamic mechanical measurements at low frequencies (≤ 1 Hz) showed evidence of the existence of an α-relaxation process. This was attributed to constrained polyether segments located at the interfacial region between the hard urea segments and the soft polypropylene glycol segments.

A prototype ohmic heating coil for the proposed Spherical Torus Experiment (STX) has been designed, fabricated, and successfully tested to 16 T, well above its design operating field and stress lev...

Poly(ethylene oxide/isoprene/styrene/isoprene/ethylene oxide) block copolymers were synthesized using potassium–napthalene catalyst in tetrahydrofuran. The dynamic and thermal properties and water absorption of these tri-block copolymers were determined and related to their bulk morphology.

The deformation of a thin, incomplete, elastic ring being pushed through a frictional channel is analyzed. The problem is formulated using the nonlinear theory of the elastica and it is found that, depending on the channel geometry, either two deformed shapes for the ring are possible, or else no solution is possible. The results are applied to the design of machines such as plain-paper copiers, self-threading tapes, and sewing machines.

The postbuckling of a thin, elastic plate in a frictional channel of rigid parallel walls is studied. Different modes of contact between the plate and the channel walls are identified and modelled using the theory of the elastica. Example results are presented which illustrate the sequence of deflections through which the postbuckled plate passes. Loading on the plate is also studied, and it is found that narrow channels arrest the initial buckling of the plate but permit a second stage of collapse at higher force levels. This work would have application to the design of automatic machinery for the handling of flexible elastic sheets such as film, cloth and paper.

A basic two-stage decomposition strategy for design optimization is described. Resolution of the independent variable vector into two parts is accompanied by a decomposition of the optimization problem equation system into a modular component and an integrating system component. The modular component must be explicitly solvable by an optimization technique, and specifically the method of optimal design is used. The integrating system component is generally the basis of control for an automated optimal design search process of reduced dimensionality. A technique is developed for handling possibilities of incompatible specifications in the modular component. Three examples illustrate application of the developed algorithm.

Electron‐spin‐density distributions in a variety of π systems have been obtained from proton‐contact interaction shifts in paramagnetic nickel II chelates of N,N′‐disubstituted aminotroponeimines. The results have furnished a great deal of new information regarding the detailed manner in which π electrons are distributed via conjugative effects. Spin‐density distributions in these systems calculated by the valence‐bond scheme are shown to be in quite good general agreement with experimental determinations. Effects attributable to hyperconjugation have been observed and the conjugating abilities of linking groups C=C, N=N, NH, O, S, and SO2 have been assessed. It is shown also that metal‐ligand π‐bond formation results in transfer of 0.1 of an unpaired electron from nickel to the π system of each of the ligands of these bischelates.

A numerical method has been developed for the solution of one-dimensional non-steady flow problems including the effects of friction, gradual area change, heat transfer between the gas and the pipe wall, longitudinal variations, and discontinuities in gas composition and entropy. The fluid considered obeys the perfect gas equation of state, but the specific heats may vary with temperature. The method is not intended for use when shocks are present, but will give an approximate solution if shocks occur. The accuracy of the new method has been checked against existing methods for more simple cases, and although the new method has been found to be slightly superior it is more complicated, much slower, and the boundary conditions are more difficult to develop. For this reason, it is suggested that the new method be used to check on the adequacy of the existing simpler methods for each new application. The methods have been compared for the case of a typical diesel engine exhaust system and it has been found that the earlier methods are adequate for all practical purposes.

Comprehensive steady and non-steady flow tests on a small radial turbine turbo-charger are given. Steady flow tests included both full admission and partial admission over the whole speed and pressure range from zero flow to maximum flow. Non-steady flow tests were carried out over a pulse frequency range from 30 to 70 pulses/s and turbine speeds from 30 000 to 60 000 rev/min with the turbine coupled to the exhaust system of a six-cylinder pulse generator under partial admission conditions. Extensive transient pressure and temperature measurements were taken upstream and downstream (pressure only) of the turbine. The total mass flow and power were also measured. A quasi-steady flow analysis was carried out using the steady flow test data. The tests results showed that for a six-cylinder exhaust pipe configuration, with two exhaust pipes entering separate nozzle segments in the radial turbine, the quasi-steady flow analysis using partial admission data grossly underestimated the mass flow and power output of the turbine. Using full admission data the ratio of measurement mass flow and horsepower to the calculated mass flow and horsepower was nearly always greater than unity. Furthermore, the average turbine efficiency was greater under non-steady flow than under steady flow. The magnitude of the recorded effects was dependent on the pulse frequency and turbine speed.