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  • Articles  (2,663)
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  • 1990-1994
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  • 1965-1969
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  • 1
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    Bulletin of mathematical biology 15 (1953), S. 311-338 
    ISSN: 1522-9602
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract The partial differential equation of the random walk problem with persistence of direction and external bias is derived. By persistence of direction or internal bias we mean that the probability a particle will travel in a given direction need not be the same for all directions, but depends solely upon the particle's previous direction of motion. The external bias arises from an anisotropy of the medium or an external force on the particle. The problem is treated by considering that the net displacement of a particle arises from two factors, namely, that neither the probability of the particle traveling in any direction after turning nor the distance the particle travels in a given direction need be the same for all directions. A modified Fokker-Planck equation is first obtained using the assumptions that the particles have a distribution of travel times and speeds and that the average time of travel between turns need not be zero. The fional equation incopporating the assumption of a persistence of direction and an external bias is then derived. Applications to the study of diffusion and to long-chain polymers are then made.
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  • 2
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    Bulletin of mathematical biology 15 (1953), S. 383-383 
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  • 3
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    Bulletin of mathematical biology 15 (1953), S. 385-385 
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    Bulletin of mathematical biology 15 (1953), S. 367-381 
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    Notes: Abstract The transmission of some information or behavior pattern is treated as a flow of “particles” which execute random motions over a population of individuals and which may multiply or disappear. Equations are derived for the number density of these “particles” and from this is calculated the number of individuals through which the “particles” have passed. The results are applied to a number of situations such as 1) uniform spatial distribution with multiplication factor decreasing with time because of loss of interest or confusion of the information, 2) multiplication factor constant but the rate of spreal decreasing with multiple hearings, 3) one-dimensional region with a small starting region with or without an absorbing barrier 4) two-dimensional region with absorbing barrier, 5) continous sources of information within a small region in one dimension, 6) uniform spatial distribution in which individuals do not respond to more than one hearing.
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  • 5
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    Bulletin of mathematical biology 15 (1953), S. 387-394 
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    Notes: Abstract A situation is considered in which a fluid containing a substance flows through a vessel at a constant rate, the substance being permeable to the vessel wall. In the region outside the vessel there is supposed to be rapid mixing in the direction perpendicular to the axis of the vessel but no mixing longitudinally. The solution for the spatial distribution at any time is given for the case of an arbitrary initial distribution along the vessel length in the absence of an input. The solution is also given for the case of a single impulsive input, the concentration being initially zero everywhere.
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  • 6
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    Bulletin of mathematical biology 15 (1953), S. 431-476 
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    Notes: Abstract Organisms orient themselves to a stimulus by two general methods. One method is by directed orientation (taxis); the other is by undirected locomotory reaction (kinesis). An equation, and the methods for finding the necessary parameters of this equation, is derived for the distribution of organisms within a container, with the following limitations: (1) the organisms have no accommodation, (2) they are always active, and (3) the stimulus changes slowly with position. Necessary modifications of the equation are then derived, so that the last two limitations may be eliminated. The equation cannot be solved excatly because of its complexity; hence an approximation method must be used. This method is discussed, an approximate solution is found, and a time constant for equilibrium to be established is derived. Applications tovarious experiments in the literature are then made with fairly satisfactory results. A new interpretation of the theory of klino-kinesis with accommodation is found upon application of the equations developed to experimental work. Further limitations and uses of these equations are then discussed.
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  • 7
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    Bulletin of mathematical biology 15 (1953), S. 501-507 
    ISSN: 1522-9602
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    Notes: Abstract Certain parameters are defined which roughly characterize the internal structure of networks. A given network structure uniquely determines the values of the parameters, but the reverse is not true. The parameters therefore define certain classes of networks. One of the parameters, thedispersion D(S) gives an indication of the “compactness” of the internal structure. Addition theorems and inequalities are derived relating the dispersions of sub-systems to the dispersion of the complete structure.
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  • 8
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    Bulletin of mathematical biology 15 (1953), S. 489-500 
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    Notes: Abstract A mathematical theory is developed which permits the determination of certain parameters of an inhomogenous tissue, such as a nerve trunk without its epineurium. The parameters are the permeability coefficients for entrance into an exit of a substance from the nerve fibers, and the diffusion coefficient of the interstitial material. The experimental data required are the dimensions of the cross-section, the average diameter of the fibers, and the ratio of the cross-sectional are of the fibers to the total cross-section, as well as the time course of the decrease of the fraction of the substance left in the nerve trunk, when the trunk is immersed in a bathing solution containing none of it.
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  • 9
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    Bulletin of mathematical biology 15 (1953), S. 509-522 
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    Notes: Abstract A model based on enzyme localization is developed which gives rise to an apparent active transport of a metabolite into or out of cells. The model is applied to three simple situations, using Fick's equation and the Rashevsky approximation. It is shown that the apparent efficiency can be made as large as desired if, for constant reaction, the outer cell region is made sufficiently small, or, for autocatalytic reaction, if the metabolite concentration in the outer region is sufficiently small. The physical limitations imposed by this mechanism are developed for all three situations.
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    Bulletin of mathematical biology 15 (1953), S. 523-533 
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    Notes: Abstract A previously derived iteration formula for a random net was applied to some data on the spread of information through a population. It was found that if the axon density (the only free parameter in the formula) is determined by the first pair of experimental values, the predicted spread is much more rapid than the observed one. If the successive values of the “apparent axon density” are calculated from the successive experimental values, it is noticed that this quantity at first suffers a sharp drop from an initial high value to its lowest value and then gradually “recovers”. An attempt is made to account for this behavior of the apparent axon density in terms of the “assumption of transitivity”, based on a certain socio-structural bias, namely, that the likely contacts of two individuals who themselves have been in contact are expected to be strongly overlapping. The assumption of transitivity leads to a drop in the apparent axon density from an arbitrary initial value to the vicinity of unity (if the actual axon density is not too small). However, the “recovery” is not accounted for, and thus the predicted spread turns out to beslower than the observed.
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    Bulletin of mathematical biology 15 (1953), S. 535-546 
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    Notes: Abstract The assumption of transitivity treated in part I is modified in various ways to describe an information-diffusion process, in which a certain amount of randomness of contact does occur. In one model a parameter is introduced which is indicative of a tendency to go beyond one's immediate vicinity to spread the information as the vicinity becomes saturated with knowers. In another model the randomness appears in the assumption that new knowers are uniformly distributed among the knowers. Two of the equations thus derived, each with two free parameters are in good agreement with experimental results.
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  • 12
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    Bulletin of mathematical biology 15 (1953), S. 1-13 
    ISSN: 1522-9602
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    Notes: Abstract The impressed field, “Window Field” (WF), due to a half-wave action potential on a muscle fiber, has been calculated on the basis of potential theory. It has been shown that in spite of the small intensity of the field, its integrated action can transfer the energy needed to induce, contraction from the membrane to the interior of the fiber. The energy of polarization has been found to be sufficient to exceed the energy of, thermal agitation on that length of fiber, which can be identified as the length of a sarcomere. The changes of ion concentration, caused by the WF, if calculated on the assumption of the semipermeability of theZ membranes, was found to be equal to the changes necessary to induce contraction of actomyosinin vitro.
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  • 13
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    Bulletin of mathematical biology 15 (1953), S. 15-21 
    ISSN: 1522-9602
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    Notes: Abstract Some general properties of the solution of the diffusion equation are deduced for the steady-state, spherically symmetric system. On the basis of these developments some results of N. Rashevsky (Bull. Math. Biophysics,11, 15, 1949) are discussed and the results of a previous investigation (Hearon,Bull. Math. Biophysics,12, 135, 1950b) are extended to more general conditions. In particular these extensions apply to the flow of a soluteagainst its concentration gradient, the nonzero gradient of an inert metabolite, and theaccumulation or exclusion of an inert metabolite in a metabolic system.
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  • 14
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    Bulletin of mathematical biology 15 (1953), S. 23-31 
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    Notes: Abstract The approximation method of N. Rashevsky is discussed and reviewed. It is shown that in addition to theexplicit assumptions and approximations there is involved the assumption that the rate of metabolism is the same at every point in the cell and that theaverage rate of metabolism is different from zero. An expression is given for the error in the approximate method when the rate of metabolism is any function of the concentration. It is also shown that a solution in theform of that obtained by the approximate method is not possible if the generalized laws of diffusion are assumed to apply.
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  • 15
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    Bulletin of mathematical biology 15 (1953), S. 33-42 
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    Notes: Abstract Rate equations for the enzymatic oxidation of succinic acid are derived on the assumption that when a single molecule of substrate combines with an enzyme molecule, it can do so with either one or two sites on the enzyme, and that oxidation occurs only in the second case. In addition it is assumed that the product of the reaction, fumaric acid, combines reversibly with the enzyme. With certain enzyme preparations the data fitted such an equation satisfactorily. In others the rate was that of a first-order reaction, but addition of cytochrome changed it to the former type. It was concluded that the transfer of hydrogen to oxygen was a first-order reaction and dominated the whole rate when enzyme preparations were used which had been washed relatively free of cytochrome. When the limiting factor was succino-dehydrogenase the rates followed the new equation. Criteria for recognizing noncompetitive inhibition are given, and inhibition by di-tertiary butyl peroxide was shown to be of this type.
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    Bulletin of mathematical biology 15 (1953), S. 43-47 
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    Notes: Abstract This paper deals with the following question: Which distributions of radiosensitivity in a population can lead to an exponential survival curve? The problem is solved exactly, with statistical fluctuations in dose fully accounted for. It is shown that only an exponential distribution of sensitivities can give rise to an exponential survival curve.
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    Bulletin of mathematical biology 15 (1953), S. 49-61 
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    Notes: Abstract An approximation method is introduced which enables a number of diffusion-type problems to be solved in an approximate but simple manner. Many cases require only the solution of a simple first-order differential equation. The method is applied to a number of cases in which the exact solutions are available. A comparison shows that the method is quite satisfactory in these cases. The method is applied to diffusion problems with rate of consumption proportional to concentration or to the square of the concentration. In the latter case, the result obtained is essentially the same as that found by H. G. Landau (1950) after elaborate calculations.
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    Bulletin of mathematical biology 15 (1953), S. 83-91 
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    Notes: Abstract It is shown that a slight modification of a model of excitatory phenomena in irritable tissues, which has been treated before, exhibits spontaneous oscillations. The frequency of these oscillations and the time-course of the potential across the model membrane have been determined, together with the dependence of some of their characteristics on some important parameters, particularly (Ca++).
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    Bulletin of mathematical biology 15 (1953), S. 73-81 
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    Notes: Abstract It is demonstrated that, if the variations of viscosity throughout a cell are considered, swelling stresses may produce elongation and division. To do this it is necessary to generalize Betti's theorem to cover systems containing viscosity gradients and such a generalization is presented. On the basis of two special assumptions it is shown that most of the results of the diffusion drag theory of cell division may be duplicated by the present theory.
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    Bulletin of mathematical biology 15 (1953), S. 63-71 
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    Notes: Abstract The theory of imitative behavior, developed previously, is applied to the case of two social groups which are separated spatially. If the information of each group as to the behavior of the other is complete, the case reduces to that of a single group. When any information is lacking at all, the two groups are independent. If we have two mutually exclusive behaviorsA andB, all four combinationsAA, AB, BA, andBB are possible. If the mutual information gradually increases from zero, then for a certain value of it, the group which is more informed about the behavior of the other will change to that behavior if it did not already exhibit it. If for constant information the size of the group increases, then above a certain threshold value, the larger group imposes its behavior on the smaller.
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    Bulletin of mathematical biology 15 (1953), S. 103-104 
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    Bulletin of mathematical biology 15 (1953), S. 107-107 
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    Bulletin of mathematical biology 15 (1953), S. 105-106 
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    Bulletin of mathematical biology 15 (1953), S. 93-101 
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    Notes: Abstract Local regulation of blood flow as determined by capillary diameter and the number of open capillaries in a region is considered. The local changes in capillary diameter and in the number of open capillaries are assumed to be due to concentration changes of a diffusible, nonspecified metabolite. This metabolite is produced in the tissue and carried away by the blood stream. Using these assumptions and applying pertinent data on capillaries, deductions are made concerning: (a) the law of blood flow as a function of temperature and capillary radius for the hyperemia of high temperature, (b) high flow as it depends on metabolism during strenuous exercise of muscle, and (c) a first approximation to the time duration of occlusion hyperemia.
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    Bulletin of mathematical biology 15 (1953), S. 109-109 
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    Bulletin of mathematical biology 15 (1953), S. 143-148 
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    Notes: Abstract The necessary and sufficient condition is given forn integers to be the score structure of a society with a dominance relation. A proof is also given for a theorem showing that there are members who dominate every other member either directly or indirectly through a single intermediate member.
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    Bulletin of mathematical biology 15 (1953), S. 111-119 
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    Notes: Abstract On the basis of a previous general formulation (Bull. Math. Biophysics,15, 21–29, 1953a) a discussion is given of the error in the approximation method of N. Rashevsky. This error, inherent in the method when the metabolic rate is different at each point in the cell, is discussed in detail and numerical values are presented for two particular cases: the rate proportional to the concentration and the rate a prescribed function of the spatial coordinates. It is shown that the formulation for the first case also applies to several other cases, that the error is negligible provided the rate is sufficiently small, and that the error is fairly sensitive to the cell size. If the rate depends upon the coordinatesalone a small rate is not sufficient to insure a negligible error. The relations between the exact method, the standard approximate method, an earlier approximate method (Physics,7 260, 1936), and a more recent refinement (Bull. Math. Biophysics,10, 201, 1948) of the standard method are discussed.
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    Bulletin of mathematical biology 15 (1953), S. 121-141 
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    Notes: Abstract It is shown on the basis of (1) conservation of mass, (2) positive concentrations, and (3) the principle of detail balancing that periodic reactions cannot occur in a closed system described bylinear differential equations. The matrix,A, of the rate equations must be such that |A|=0,a ij〉0 fori≠j,a ii〈0, andVAV −1=B, whereV is diagonal andB is symmetric. These properties ofA imply that the latent roots are real and non-positive and that neither catalysis nor inhibition can be described bylinear equations. It is further shown that periodic reactions cannot occur in anopen system for which the matrix associated with the chemical reactions has the above properties and in which thesimple law of diffusion is obeyed. The relation of these results to Onsager's reciprocal relations and to previous work on periodic and cyclic chemical reactions is discussed. The utility of certain of these results for the treatment of isotope kinetics is indicated.
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    Bulletin of mathematical biology 15 (1953), S. 149-152 
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    Notes: Abstract It is demonstrated that an explanation of the small radius effect or the so-called sigma phenomenon may be obtained by noting that one of the effects of the presence of suspended particles in a flowing fluid is to increase the velocity of flow near the wall over that existing in the absence of particles. This effect may be considered equivalent to relaxing the boundary conditions at the wall. An expression for the viscosity is compared with data and fit is found to be good.
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    Bulletin of mathematical biology 15 (1953), S. 153-159 
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    Notes: Abstract The solution for the spatial distribution of ions in a Donnan equilibrium has been given by J. H. Bartlett and R. A. Kromhout (1952). The present note gives an explicit solution for the case in which the length of the region containing the membrane is large; in biological situations this requires only that the length considered should be greater than a few hundred Ångstrom units. The Donnan equilibrium may be considered to be a special case of a situation in which forces other than electrical act upon the ions; in particular, it represents the case in which only one ion is acted upon and the energy difference on the two sides of the membrane is infinite. An expression is given for the difference in energy of theith in terms of the electrical potential and of the ion concentrations. As an illustration, the results are applied to nerve membrane potentials.
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    Bulletin of mathematical biology 15 (1953), S. 161-165 
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    Notes: Abstract A mechanism is described which accounts for the active transport of Na+ ions through a membrane. It is assumed that at one side of the membrane the ion combines with a carrier ion, the resulting carrier compound then diffuses through the membrane and decomposes at the other side of the membrane. The free diffusion of the ions is also taken into account. The time rate of accumulation of the ion in question at the latter side of the membrane is calculated in terms of the concentrations of the ion at both sides of the membrane.
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    Bulletin of mathematical biology 15 (1953), S. 167-171 
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    Notes: Abstract The recent extension of the approximation method is applied to enable us to arrive at the time course of the concentrations at both sides of a membrane. From the differential equations which govern these, the steady-state solution is obtained in terms of the parameters, which are determined by the thickness of the diffusion layers, the chemical composition and reactions, and the diffusion constant of the membrane.
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    Bulletin of mathematical biology 15 (1953), S. 173-183 
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    Notes: Abstract An equation is derived from the spread of a “state” by contact through a thoroughly mixed population, in which the probability of transmission depends both on the over-all duration of the process and on the time an individual has been in the “state.” Cases in which this probability is a function of only one or the other of the two “times” are worked out. It is shown that in the case of dependence on “private time” alone the asymptotic value of the fraction of the population effected is the same as that derived by the random net approach.
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    Bulletin of mathematical biology 15 (1953), S. 235-235 
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    Bulletin of mathematical biology 15 (1953), S. 185-195 
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    Notes: Abstract The reflection of pressure waves in a fluid enclosed within a tube with an elastic wall is studied for the case of a localized change in diameter of the tube. The concept of impedance is introduced. The relation of the reflection characteristics of the parts of the tube at either side of the change is derived on the basis of the continuity of pressure and mass flow at the site of the change. This relations is used to derive the expression for the ratio of the pressure oscillations measured in front of, and behind, the constriction in terms of the constants of the system. As a result, a method is indicated to locate the coarctation from measurements of the pressures in front of, and behind it.
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    Notes: Abstract The question is raised concerning the possible causes of abnormally small standard deviations found in counting samples in which particles are distributed at random (e.g., blood cells, fat globules in milk, etc.). The effect of discarding abnormal samples is discounted inasmuch as small standard deviations occur even when all samples are counted. An approximation method is used to calculate the effect of finite particle size, of known repulsive forces between particles and of convection currents. This calculation shows that neither finite size nor the known repulsive forces are sufficient to account for the observed abnormality of standard deviation, but that convection currents can possibly account for it. The possible presence of long-range repulsive forces cannot, however, be excluded.
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    Bulletin of mathematical biology 15 (1953), S. 245-250 
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    Notes: Abstract The effect of finite particle size on the standard deviation in sample counts is computed for the one-dimensional case. To a first order of approximation the correction is found to be identifical with that found by H. de Vries (1953) using a general approximation method.
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    Bulletin of mathematical biology 15 (1953), S. 251-260 
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    Notes: Abstract A critical examination of the “classical” theories of photoreception in view of more recent experimental findings yields the result that these theories do not possess the property to describe all the more significant phenomena of photoreception correctly, and to some extent suffer the lack of more general applicability. The basis for a new and presumably more general theory of photoreception based on dynamical aspects is laid out. Emphasis is put on the time course of afferent and efferent excitation in the photoreception model, consisting of a receptor element, an afferent and an efferent neuron of the one-factor Rashevsky-type, and an effector organ.
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    Bulletin of mathematical biology 15 (1953), S. 197-234 
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    Notes: Abstract A mathematical model for the development of human society, beginning with the earliest stages of urban cultures, is outlined. In the early stages of history, behavior was characterized largely by adherence to a number of beliefs and prejudices of diffeirent kinds, which were accepted on faith and not subject to critical rational analysis. Due to psychobiological variability a very small number of individuals spontaneously appear at all times who challenge the accepted beliefs and prejudices and do not follow the accepted patterns of social behavior. The effect of these individuals upon the rest of the society, especially upon the younger generation, depends on the facilities with which information spreads in society. In earliest societies, when modern methods of mass communication were unknown, the channels of communication were practically identical with the channels of economic transport. The latter in its turn depended on the nature of the roads, and especially on the presence of waterway, which facilitated transportation. The sizes of the earliest cities and the distances between them were largely determined by relative ease of transporation. Expressions are derived for the average size of the earliest cities and for the average distance between them. The calculated average populations of the earliest cities are of the order of 103; the distance of the order of 102 km. Both are in agreement with some archaeological findings. An expression for the time spaon required for the development from the earliest stages of urban cultures to the present time is derived and shown to depend on the specific shoreline of the country, that is, the length of the shorline divided by the area of the country. It is pointed out that western Europe's specific shoreline, including land bordering both seas and rivers, is ten times as large as the shoreline area of other parts of the world. It is shown that this greater specific shoreline may account quantitatively for the faster social and technological development of western Europe in the last few centuries. The calculated total span of time of development from earliest urban cultures to our days is found to be of the order of magnitude of ten thousand years. It is shown that the model accounts for the existence at the present time of primitive cultures. A number of suggestions is made in regard to other possible applications of mathematics to history.
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    Bulletin of mathematical biology 15 (1953), S. 269-276 
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    Notes: Abstract The assumptions latent in the derivation of the integral equation of Branson are rendered explicit and discussed. It is shown that the equation is valid only for systems in which the substance disappears according to a linear rate law.
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    Bulletin of mathematical biology 15 (1953), S. 261-268 
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    Notes: Abstract It is shown that the validity of Branson's integral description of metabolizing systems is subject to severe limitations. The validity is insured only in cases where the reaction is of first order, or quasi of first order. In all other cases Branson's equation has to be modified to insure general applicability. The consequences of a different definition of the metabolizing functionF have also been investigated. With the new definitionF describes the pure effect of metabolization. It is found that in this case the integral equation is only capable of describing first-order reactions. With a slight modification of the integral equation it is possible to describe metabolites “with age”, which do not have reactions of definite order, but which satisfy the superposition principle.
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    Bulletin of mathematical biology 15 (1953), S. 277-292 
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    Notes: Abstract A problem in probability is stated with included the problem of the distribution of bacterial mutants as a special case. This problem is solved exactly but since the resulting expressions are too complicated for practical use, various approximate expressions for the distribution are considered, especially for the bacterial mutation case.
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    Bulletin of mathematical biology 15 (1953), S. 293-300 
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    Notes: Abstract Simple reaction and discrimination reaction, under the influence of imitation, are considered for the situation in which the stimulus or the stimuli vary slowly with time. The result is analogous to hysteresis under certain conditions. The calculations are facilitated by the solution of $$x = \int_{ - \infty }^{a + \beta x} {g\left( \xi \right)d} \xi ,$$ g(ξ) being the normal error function. Values ofx(α, β) are given in a table.
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    Bulletin of mathematical biology 15 (1953), S. 301-309 
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    Notes: Abstract On the basis of simple physical considerations the blood flow in a branching circulatory system is studied. The case of two groups of parallel vessels is treated. The vessels of the same group are supposed to be identical. The resistance of each group is determined by the resistance of each vessel in the group and by the number of vessels in the group. From the dependence of the resistance of each vessel on its radius an expression is obtained for the blood flow through each group of vessels in terms of the numbers and sizes of the vessels in each group. The number of open vessels in an organ and the radius of each of those vessels are assumed to depend on the metabolic rate of that organ. The relations so obtained, together with the expression above, are applied to derive the blood flow through an organ as a function of the metabolic rate of that organ. It is indicated that the relations obtained might describe the shifting of blood from one organ to another if the activity of one of them changes. A way is pointed out to treat neural regulation of this phenomenon.
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    Bulletin of mathematical biology 15 (1953), S. 361-365 
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    Notes: Abstract A stochastic model of population growth is treated using the Bellman-Harris theory of agedependent stochastic branching processes. The probability distribution for the population size at any time and the expectation are obtained when it is assumed that there is probability (1−σ), 0≤σ〈1, of the organism dividing into two at the end of its lifetime, and probability σ that division will not take place.
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    Bulletin of mathematical biology 15 (1953), S. 339-359 
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    Notes: Abstract In a previous paper, in which a possible mathematical approach to history was outlined, it was shown that urbanization plays an important part in the propagation of new ideas. The rate of such propagation influences the rate of historical developments. The present paper deals in more detail with possible mechanisms of formation of earliest cities. Equations are derived which give the limiting size of such cities and their rate of growth. Of particular importance for the spread of new ideas is the spread of information. The latter largely depends on the fraction of individuals who travel between city and country. Expressions for this quantity are derived. An approach is outlined to the mathematical study of the earliest social classes, which may have been formed as a result of military, religious, or economic stratifications.
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    Bulletin of mathematical biology 15 (1953), S. 395-409 
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    Notes: Abstract The velocity of propagation of a disturbance wave in a liquid flowing in a distensible tube is computed. The mathematical model is more general than those used in previous analyses: the tube wall properties are realistic; the convective part of the axial inertia forces is taken into account; radial inertia forces of both the fluid and tube wall are present; viscous stresses are present. Four parameters influencing the velocity of propagation are obtained and discussed. Curves are plotted illustrating the effects of the parameters. Contrary to the results of previous analyses, viscous effects are shown to be appreciable in blood flow. It is also shown that radial inertia effects can be important in laboratory set-ups.
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    Bulletin of mathematical biology 15 (1953), S. 411-429 
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    Notes: Abstract A general theory of the drying of frozen tissue is developed and applied to the measurement of the drying rate of frozen guinea pig liver. It is shown that for a given temperature of the subliming ice crystals the mininum drying time of a piece of guinea pig liver is greater than the minimum sublimation time of a piece of ice of the same size and shape by a factor of the order of one thousand. This fact has many implications in the design of freeze-dry apparatus which will be developed in a following paper.
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    Bulletin of mathematical biology 15 (1953), S. 477-488 
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    Notes: Abstract The equations governing the time course of the exchange of substances between the blood in the capillaries and the extracellular space are solved for the case of substances which do not penetrate the cells. The equations given relate the time course of the exchange process to the various tissue and circulation parameters such as the specific capillary wall area, the pore area, the inter-capillary distance, the size of the extra-vascular, extra-cellular space, the diffusion coefficient in this space, and the velocity of blood in the capillaries. Some experimental work on capillary exchange is discussed in relation to the theory and estimates are made of the relative importance of the various tissue and circulation parameters in the exchange of substances in different tissues.
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    Notes: Abstract Previous work (Macey, 1952) in the application of the one-factor theory to the heart is extended. The rate of production of the excitatory state is assumed to be linear. Two possible mechanisms are indicated whereby such a situation might arise. Assumptions are made regarding the mode of action of the chemical mediators on the heart, and an equation is derived relating the heart rate to the frequency of nerve impulses traveling along the cardiac nerves. This result compares favorably with the experimental findings of A. Rosenblueth and F. A. Simeone (1934). Other experimental results are interpreted in terms of the theory.
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    Bulletin of mathematical biology 15 (1953), S. 561-563 
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    Helgoland marine research 4 (1953), S. 260-315 
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    Helgoland marine research 4 (1953), S. 239-254 
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    Notes: Zusammenfassung Der im Verlauf zweier Jahre untersuchte Algenbewuchs der Fahrwassertonnen um Helgoland bestand aus Algen der Gezeiten-, Supra- und oberen Sublitoralzone. Ihre Häufigkeit entsprach durchweg den Helgoländer Verhältnissen, es fehlten jedoch die drei bei Helgoland sehr reichlich vorkommendenFucus-Arten (F. platycarpus, F. vesiculosus undF. serratus). Einige Algen (fädige Grünalgen,Bangia, Enteromorpha, Punctaria, Ceramium, Polysiphonia undLaminaria) konnten in gürtelförmigen Zonen auftreten; diese sind schmäler als am natürlichen Standort. Der Algenanwuchs verringert sich mit zunehmender Entfernung von der Insel.
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    Acta biotheoretica 11 (1953), S. 1-26 
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    Notes: Summary After a short review of the historical development of the problem of cytoplasmic inheritance, the principles for the proof of cytoplasmic inheritance were discussed. At present the proof can be based on the maternal transmission of plasmagenes, on the missing of mendelian segregation and on the possibility of a segregation during ontogenetic development. In the following the most important possibilities for errors and their refutation onEpilobium were discussed: elimination of genotypes (examination of the elimination of gametes, zygotes, test of accidental distribution of chromosomes, crossing with tetrads), abnormal cytology (cytological investigation, crosses with hetero- and polyploids), maternal aftereffects (clone-multiplication), predetermination (exchange of nucleus by backcrossing), nuclear produced plasmagenes (contrarily acting cytoplasm and nucleus) and transmission of parasites or symbionts as virus (grafting). At the end the principles for the distinction between different cytoplasmic constituents were discussed.
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    Acta biotheoretica 10 (1953), S. 105-138 
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    Description / Table of Contents: Résumé Suivant A. V.Hill on a développé dans une étude mathématique les formules qui se rapportent aux procédés de diffusion dans la physiologie. Pour l'introduction, on donne une explication des problèmes. Puis on fait suivre le développement mathématique (méthode de l'intégration deBernoulli, transformationLaplace) qui permettent l'intégration de l'équation différentielle de la diffusion. Dans la partie spéciale, on étudie des problèmes concrets de la physiologie respiratoire. Pour la diffusion dans des cylindres cellulaires on a trouvé le résultat de la concentration d'une substance en dépendance du lieu et du temps où on a tenu compte à une consommation constante. De même, on a réussi a résoudre le problème du changement temporel de la concentration moyenne. Il est nécessaire de traiter en particulier le cylindre dans des conditions spéciales c'est-à-dire quand il est approvisionné du dehors et d'un tube capillaire et central (cylindreKrogh). On a expliqué les équations différentielles par des cas spéciaux et par des tableaux numériques. Puis on a étudié la provisionnement stationnaire des cylindres cellulaires en cas que outre la composante de diffusion radiale, il faut tenir compte à une composante de diffusion axiale (Längsdiffusion). Les résultats obtenus par les formules développées correspondent bien aux valeurs trouvées par les expériences.
    Notes: Summary Following A. V.Hill, those formulae are developed in a mathematical research which are of interest in the field of physiological diffusion processes in cylindrical objects. At first, an introduction into the problem is given. Then a development follows of the mathematical methods (Bernoulli's method [Produktansatz],Laplace-transformation) which are suitable for the integration of the partial differential equation of the diffusion. The special part contains the investigation of problems which are importance for the physiology of respiration. Thus the query is answered for the concentration of a substance in dependance of time and place for the diffusion in tissue cylinders taking into consideration a constant rate of consumption, as well as the query of the temporal alteration of the average concentration. The cylinder fed from the outside and the one fed from a central capillary (Krogh's) must hereby be specially treated according to the boundary conditions. The developed equations are explained by special examples and numerical lists. Further, the steady state of supply of tissue cylinders is investigated in case that apart from the radial also an axial diffusion component (Längsdiffusion) has to be counted with. The numerical results from the developed formulae are in good agreement with the values found by experiments.
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    Acta biotheoretica 11 (1953), S. 27-44 
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    Acta biotheoretica 10 (1953), S. 139-212 
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    Mycopathologia 6 (1953), S. 241-259 
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    Mycopathologia 6 (1953), S. 354-377 
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    Mycopathologia 6 (1953), S. 325-336 
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    Notes: Summary A mild to moderate moniliasis in mice was rendered more severe by periodic treatment with cortisone acetate. This enhanced severity of infection occurring in male and female animals was no greater, however, than could be atributed to the deleterious effect of the cortisoneper se, as evidenced by the results on uninfected animals treated similary with cortisone. Infected male animals treated periodically with the aqueous vehicle of cortisone revealed an enhanced severity of monilial involvement; female mice similarly infected and treated showed no modification of the severity of infection. A severe moniliasis induced by suspending theCandida cells in mucin was reduced in severity for male, but not for female mice by the same schedule of cortisone treatment as used above. The effect of the aqueous vehicle on such a severe monilial involvement was similar to that found with mildly infected mice. The possible significance of these observations are discussed.
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    Mycopathologia 6 (1953), S. 298-300 
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    Notes: Summary 1. Granule formation byCandida albicans in the internal organs of experimental animals is described. This appears to be the first time such an observation has been made. 2. Ring formation by fungi under different conditions is cited, and although different explanations have been proposed by different authors, the supposition is made that a common growth pattern is involved.
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    Mycopathologia 6 (1953), S. 310-316 
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    Notes: Summary This study presents an antigenic comparison of the fungi,B. brasiliensis andB. dermatitidis, by intradermal reactions in animals and humans. Guinea pigs, hypersensitive to the homologous infecting fungus, reacted when skin tested with standardized broth filtrates and yeast-phase vaccines of the heterologous organism. Similar results were obtained in the limited number of human cases of North American blastomycosis when the yeast-phase vaccines were employed. A statistical method, the 50 per cent end-point, was utilized for standardizing broth filtrates of fungi to be employed as skin test antigens.
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    Mycopathologia 6 (1953), S. 337-353 
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    Notes: Summary 1. It was not possible to protect mice from the lethal effects of a cold environment by using cortisone if the mice had previously been infected with moniliasis. This was true whether the induced infection was a mild or severe one. 2. Only in female mice infected with moniliasis and treated with cortisone and STH was it possible to demonstrate a reversal of the deleterious effect of cortisone onCandida-infected mice. In female mice severely infected and treated with cortisone and STH, the mortality rate was less severe than that found for female mice infected with moniliasis and treated with cortisone or female mice infected but untreated. 3. Male mice severely infected profited from treatment with cortisone by showing a reduced mortality rate but this effect was completely reversed by treating infected male mice with cortisone and STH. 4. The significance and possible role of the interrelated factors of severity of infection, sex of animal, amount of cortisone and its dosage schedule, amount of STH and its dosage schedule, type of aqueous vehicle, and environmental temperature are discussed.
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    Mycopathologia 6 (1953), S. 260-289 
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    Mycopathologia 6 (1953), S. 290-297 
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    Description / Table of Contents: Sommaire et Conclusions 1. La littérature concernant la pathologie et l'immunologie deCandida albicans est brièvement passée en revue. 2. Les méthodes d'experimentation et les techniques employées dans cette étude sont presentées. 3. Les observations faites pendant les experiences montrent que: a Beaucoup des lésions trouvées differaient de celles décrites parCecil etJacobson. b L'immunisation n'a pas semblé préserver la vie de l'animal ni prolonger la période de survie au dela de celle des animaux de contrôle. L'impression générale est que l'immunisation fut, non seulement inefficace, mais peut-être nuisible. c L'antisérum semble avoir eu, sur la morphologie des organismes, quelque effet démontré par le mycélium multibranche, les blastospores tordus aux parois épaisses, dans certains cas un conglomérat très dense des organismes et la présence de typiques “sulfur granules”, la forme actoinomycetoide des organismes chez un certain nombre d'animaux. d L'antisérum semble avoir eu peu ou pas d'effet sur la réaction tissulaire.
    Notes: Summary and Conclusions 1. The literature on the pathology and immunology ofCandida albicans is briefly reviewed. 2. Experimental methods and techniques used in this study are presented. 3. Experimental observations described here show that: a Many of the lesions found differed from those described byCecil andJacobson. b The immunization did not seem to preserve the life of the animal nor did it extend the survival time over that of the controles, the general impression being that it was not only ineffective but possibly deleterious. c The antiserum seemed to have some effect on the morphology of the organisms shown by the multibranched mycelium, the thick-walled, distorted blastospores, the heavy packing of the organisms in some cases and the presence of typical “sulfur granules”, the actinomycetoid form of the organisms, in a number of animals. d The antiserum seemed to have little or not effect on the tissue reactions.
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    Mycopathologia 6 (1953), S. 317-324 
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    Notes: Summary This study presents an immunologic comparison of the fungi,B. brasiliensis andB. dermatitidis, by serologic reactions in animals and in humans. The complement fixation test was used to test the sera of rabbits with various homologous and heterologous antigens of the two fungi: yeast-phase, broth filtrates of the mycelial phase, and “purified” protein. A definite cross-reactivity was observed. Sera from humans infected withB. dermatitidis orB. brasiliensis also were tested by complement fixation reaction with homologous and heterologous antigens: yeast-phase, broth filtrates of the mycleial phase, and “purified” protein. Two of nine sera from cases of North American blastomycosis, giving positive reactions with the homologous antigens, cross-reacted at a low titer with the heterologous antigens. Five of eleven sera, positive withB. brasiliensis antigens, reacted with one or more types ofB. dermatitidis antigens. There was no correlation between titer obtained with the homologous antigens and that obtained with the heterologous antigens. Immunization of rabbits was best achieved by use of massive doses of sonic-vibrated yeast-phase cell suspensions. Data were presented indicating the greater fragility ofB. brasiliensis yeast-phase cells as compared withB. dermatitidis cells of the same phase. Evidence was obtained by subjecting cells to sonic vibrations.
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    Development genes and evolution 146 (1953), S. 115-136 
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    Development genes and evolution 146 (1953), S. 403-406 
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    Development genes and evolution 146 (1953), S. 371-402 
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    Development genes and evolution 146 (1953), S. 407-420 
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    Development genes and evolution 146 (1953), S. 421-432 
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    Development genes and evolution 146 (1953), S. 433-486 
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    Development genes and evolution 146 (1953), S. 487-514 
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    Development genes and evolution 146 (1953), S. 544-579 
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    Development genes and evolution 146 (1953), S. 515-536 
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    Notes: Zusammenfassung 1. Bei 2–3 Monate alten Larven vonTriton alpestris werden rechteckige Epidermisstücke aus der Flanke der einen Körperseite herausgeschnitten. 2. Die Wundfläche wird im Laufe von 24 Std durch allseitige Zuwanderung von Epidermiszellen bedeckt. 3. An der Wundheilung sind außer den Grundzellen der Epidermis auch die ausdifferenziertenLeydigschen Drüsenzellen in vollem Ausmaße beteiligt. 4. Über der Wundregion kommt es zu einer überschüssigen Akkumulation von Leydig-Zellen; ihr entspricht eine starke Verarmung in allen Epidermisarealen, welche die Wundränder umgeben. 5. Die durch Wanderung bedingte Veränderung in der Verteilungsdichte der Leydig-Zellen wurde quantitativ erfaßt, und der Einflußbereich der Wundregion bestimmt. 6. Zellvermehrung durch Mitose spielt bei den Regenerationsvorgängen bis zum 8. Tage nach der Operation keine nachweisbare Rolle. 7. Durch Colchicin und durch ein Aminoketon kann die reparative Zellbewegung gehemmt werden.
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    Development genes and evolution 146 (1953), S. 589-592 
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    Development genes and evolution 146 (1953), S. 580-588 
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    Notes: Zusammenfassung 1. Die sandalenförmige Einschnürung der Keimscheibe wird im allgemeinen bei Keimscheiben von wenig Urwirbelpaaren kenntlich; man kann jedoch die Stelle der späteren Einschnürung in frühere Entwicklungsstufen zurückverfolgen. 2. Die Area embryonalis zeigt zu der durch die Stelle der stärksten Verengung gelegten Querebene ein wechselndes Verhalten. Die Querebene trifft vorerst den Primitivstreifen, dann den Primitivknoten, hierauf das unsegmentierte kranial vom Knoten gelegene Mesoderm, endlich die Urwirbel. 3. Die tatsächliche Verschmälerung der Keimscheibe im Bereich der Einengung wird auf die medial gerichtete, zur Mesodermbildung führende Bewegung des Ektoblasten nachGraeper, zurückgeführt. 4. Die Verschiebung des Primitivknotens gegenüber der Einengungsstelle wird gleichfalls gestaltungsdynamisch erklärt, wobei wir zu ähnlichen Ergebnissen kamen wieGraeper undWetzel, wenngleich wir betreffs der genauen Richtung der Bewegungsphasen in einzelnen Punkten abweichen.
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    Development genes and evolution 146 (1953), S. 537-543 
    ISSN: 1432-041X
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    Description / Table of Contents: Zusammenfassung 1. Es wurden an Hühnerkeimscheiben die Folgen einer zunehmend langen Abkühlung nach der Eiablage untersucht. 2. Bei einem Aufschub der Anbrütung bis zum 7. Tage zeigen die Keimlinge keine Änderungen der Morphogenese. In der Organisation von Keimlingen mit einem Aufschub von 12 und mehr Tagen entstehen Veränderungen der Entwicklung (Unterdrückung). Die länger zurückgehaltenen Embryonen neigen zu einer stärkeren Verkürzung ihrer Achse. 3. Die axialen Strukturen der Keimlinge werden in Gestalt und Ausdehnung reduziert, bis sie bei solchen, die vor der Bebrütung 15–20 Tage zurückgehalten waren, überhaupt fehlen. Die Keimscheiben dehnen sich zu einem flächigen Gebilde aus, das keine Anzeichen von Organisation mehr zeigt. 4. Hat die Abkühlung länger als 20 Tage gedauert, so werden die Keimlinge zunehmend entwicklungsunfähig. 5. Die wahrscheinliche Erklärung für die Entstehung dieser morphogenetischen Merkmale wird in der Denaturierung von „Zellsubstanzen“ durch Wasserverlust, in der Unterdrückung von mitotischer Aktivität und von morphogenetischen Bewegungen der Zellen des Keimlings gesucht.
    Notes: Summary 1. The progressive effects of temperature fasting on the blastoderms of chick have been studied. 2. The blastoderms do not show any morphogenetic change up to the 7th day of delay prior to incubation. Embryological changes in form of suppression arise in the organisation of blastoderms delayed over 12 days or more. The axes of the embryos tend to be more shortened in the further delayed embryos. 3. The axial structures of the blastoderms suffer reduction in shape and size until they disappear in the blastoderms kept waiting for 15 to 20 days. The blastoderms enlarge into a sheet-like structure without any mark of organisation. 4. The blastoderms become gradually incapacitated beyond the temperature-fasting for over 20 days. 5. The probable mechanism of these morphogenetic features have been sought in the denaturation of “Cell substances” by dehydration, suppression of mitotic activities and morphogenetic movements of cells of the blastoderms.
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    Cellular and molecular life sciences 9 (1953), S. 16-17 
    ISSN: 1420-9071
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    Notes: Zusammenfassung Chromatographische Beobachtungen stützen die auf spektraltheoretische Berechnungen basierte Annahme vonH. Kuhn, dass in gewissen Zyaninfarbstofflösungen ein Gemisch von cis-trans-isomeren Formen vorliegt.
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    Cellular and molecular life sciences 9 (1953), S. 7-16 
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    Notes: Summary A concise survey is given of the possibilities of producingmotherlike descendants: the so-called “maternal hybrids”, after interspecific pollinations in flowering plants. On the basis of his extensive experiments in pollination and interspecific crossings with species of different sections of the genusPrimula, the author believes that he has proved that the motherlike descendants from interspecific crossings inPrimula—as in other genera likeSolanum andDigitalis—are the result neither of amphimictic combination nor of partial aposporic or pseudogamic reproduction. They are rather the result of parthenogenetic embryo formation in developing seeds, the smaller part perhaps of haplo-, the greater and more conspicuous part of diplo-parthenogenesis. With these unexpected additions, the possibilities of the origin of motherlike descendants from interspecific crossings now include: (1) Mother (or Father-) like descendants fromnormal amphimictic reproduction after crossings of two species from which the one transfers the dominant, the other the recessive alternatives of the distinguishing morphological and physiological characters. (2) Motherlike descendants ofnon-amphimictic origin after interspecific pollination on and withobligate or partial aposporic and pseudogamic species. (3) Motherlike descendants ofnon-amphimictic origin from interspecific crossings of normal sexual species,from seeds with embryos from haplo- or diplo-parthenogenetic development. With the description of this third category of formation of motherlike descendants, the circle of possibilities seems to be closed. One may now presume that all facts or “maternal hybrids” cited—except those from crossings with definitely proved “experimental errors”—can be explained by one of the possibilities cited above.
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    Cellular and molecular life sciences 9 (1953), S. 26-27 
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    Notes: Zusammenfassung Die Wirkungsgeschwindigkeiten von intravenös injiziertem Vitamin K1, Methylnaphthochinon und Synkavit in Vitamin-K-frei ernährten Küken wurden verglichen. Es zeigte sich, dass in den ersten Stunden nach der Injektion Vitamin K1 die Prothrombinzeit viel schneller zum Absinken brachte als die beiden anderen Verbindungen.
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    Cellular and molecular life sciences 9 (1953), S. 31-32 
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    Notes: Zusammenfassung Die im Hydergin enthaltenen dihydrierten Mutterkornalkaloide zeigen keine Schutzwirkung gegen das experimentelle akute Lungenödem durch Chlorpikrin beim Kaninchen. Diese Feststellung schliesst die Teilnahme des sympathischen Nervensystems in der Pathogenesis dieser Art von akutem experimentellem Lungenödem aus.
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    Cellular and molecular life sciences 9 (1953), S. 30-31 
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    Notes: Zusammenfassung Die im Hydergin enthaltenen dihydrierten Mutterkornalkaloide entfalten eine Schutzwirkung gegen das akute experimentelle Lungenödem durch Adrenalin beim Kaninchen bei Darreichung sowohl während einer weit fortgeschrittenen Wirkungsphase des Pharmakons wie auch während der Krise selbst. Solche Eigenschaften, welche der sympathikolytischen Wirkung des Hydergins zuzuschreiben sind, bestätigen die Teilnahme des sympathischen Nervensystems in der Pathogenesis dieser Art von akutem experimentellem Lungenödem.
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    Cellular and molecular life sciences 9 (1953), S. 29-30 
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    Notes: Summary In castrated guinea pigs injected with testosterone propionate (100–250 γ per 100 g daily for 4 days), the thymus underwent atrophic modifications, characterized chiefly by the diminution of the lymphocytes. In thyroidectomized castrates, injected with thyroxine (6 γ per 100 g and 24 h) in order to prevent the thyroprive atrophy of the thymus, testosterone injections failed to produce any modifications of the thymus. Thus structural changes induced by testosterone injections could be interpreted as the consequence of the stimulation of the thyroid by this hormone.
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    Cellular and molecular life sciences 9 (1953), S. 35-36 
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    Notes: Summary A source of disturbance in certain serological experiments was removed after 6 weeks of search, when it was discovered to be caused by traces of the product “Vel” (a washing powder) with the glass-ware was cleaned.
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    Cellular and molecular life sciences 9 (1953), S. 368-369 
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    Notes: Zusammenfassung Bei der Permanganatoxydation und der Kalischmelze der Reserpinsäure wurden 4-Methoxy-oxalylanthranilsäure und 5-Oxyisophtalsäure isoliert. Als Arbeitshypothese wird deshalb für Reserpinsäure eine Yohimbanstruktur postuliert. Durch die obigen Abbauergebnisse ist die Stellung der einen Methoxylgruppe festgelegt, wogegen die Haftstellen der drei weiteren funktionellen Gruppen noch nicht gesichert sind.
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    Cellular and molecular life sciences 9 (1953), S. 357-367 
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    Notes: Zusammenfassung Es wird eine Übersicht über die Kohlenstoffgerüste der Sesquiterpene, Diterpene und Triterpene gegeben. Die Isoprenregel zeigt in jeder dieser Gruppen besondere Eigenheiten. Auch die C30-Steroide und ein Steroid mit 31 Kohlenstoffatomen, die mit den Triterpenen verwandt sind, werden besprochen. Die Zusammenhänge zwischen Diterpenen und Triterpenen in bezug auf ihre Konstitution und Konfiguration werden diskutiert, wobei auf die weitgehende Übereinstimmung ihrer Konfiguration mit der Konfiguration der Steroide hingewiesen wird. Die kürzlich durch die Experimentalarbeiten vonBloch gewonnenen Kenntnisse über die biologische Entstehung des Cholesterins aus Essigsäure, unter sehr wahrscheinlicher Zwischenbildung des Triterpens Squalen, geben Anlass zur Erörterung hypothetischer Wege für die Biogenese der pentazyklischen Triterpene aus Squalen, der zyklischen Sesquiterpene aus Farnesol, der zyklischen Diterpene aus Geranyl-geraniol und schliesslich auch der zyklischen Monoterpene aus Geraniol, unter Beachtung der elektronischen Zyklisierungsmechanismen der organischen Chemie. Schliesslich wird die «biogenetische» Isoprenregel definiert und ihre Bedeutung diskutiert.
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    Cellular and molecular life sciences 9 (1953), S. 369-369 
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    Notes: Zusammenfassung Die infraroten und ultravioletten Spektren und analytische Daten von Geissospermin wurden diskutiert. Die Spaltung von Geissospermin mit konzentrierter Salzsäure wurde wiederholt, und ein Spaltprodukt C19H26ON2 wurde durch Gegenstromverteilung rein iscliert und durch ein kristallines Pikrolonat charakterisiert. Dieses Produkt besitzt ein Dihydroindolspektrum und trägt die N-methylgruppe des Geissospermins.
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    Cellular and molecular life sciences 9 (1953), S. 370-370 
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    Notes: Zusammenfassung Die Konstanten, welche das Gleichgewicht zwischen Isonikotinsäurehydrazid (I) und den mit Schwermetallen gebildeten Komplex (III) beherrschen, werden ermittelt. Die Bedeutung dieser Konstanten für die Chemotherapie der Tuberkulose werden diskutiert.
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    Cellular and molecular life sciences 9 (1953), S. 372-373 
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    Notes: Résumé Il est possible d'induire des mutations chez le bactériophage virulent T3. Il faut pour cela irradier avec des rayons ultravioletset les bactériophageset les bactéries dans lesquelles ils se multiplieront. Les mutations dont on a mesuré la fréquence concernaient le spectre d'action des phages (T3h), mais on en a observé d'autres agissant sur la morphologie des plaques.
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    Cellular and molecular life sciences 9 (1953), S. 376-377 
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    Notes: Résumé Le niveau apparent de survie des cellules d'Escherichia coli irradiées par rayonnement ultra-violet peut être modifié par « post irradiation » avec des inhibiteurs du métabolisme cellulaire.
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    Cellular and molecular life sciences 9 (1953), S. 377-379 
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    Notes: Summary An autoradiographic method, based on the observation of individual particles, was used to determine the relative specific radioactivity of RNA and of the proteins in the different parts of the oocytes ofAsterias rubens. The nucleolus incorporates glycine in both fractions about 100 times more rapidly than the cytoplasm.
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    Cellular and molecular life sciences 9 (1953), S. 373-374 
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    Notes: Zusammenfassung Durch Gefriertrocknung nachAltmann-Gersh wurden zytologische Präparate von einer genetisch geprüften polyploiden Serie von Hefe hergestellt. Die gemessenen Werte für Kern- und Zellgrössen stimmen in der theoretisch erwarteten Weise mit dem Grade der Polyploidie überein. Damit ist eine von höheren Organismen bekannte zytologische Erscheinung zum erstenmal für Mikroorganismen demonstriert. Die Befunde stehen im Widerspruch zuLindegrens Annahme einer «Kernvakuole» und zuSubramaniams genetisch nicht fundierten Einwänden gegen die Brauchbarkeit von Einzelsporen-Kulturen, ebenso zur Ansicht des letztgenannten Autors, dass zytologische Unterschiede bestehen zwischen Zellen aus Gärungs- und solchen aus aeroben Kulturen.
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    Cellular and molecular life sciences 9 (1953), S. 374-376 
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    Notes: Zusammenfassung Ultraviolettbestrahlung von Hefekulturen bewirkt, dass nachher ein Teil der Zellen gegenüber der inaktivierenden Wirkung von Röntgenstrahlen vermehrte Resistenz besitzen. Es konnte gezeigt werden, dass dies durch Zellveränderungen bedingt ist. Da beiTradescantia undDrosophila ultraviolette Strahlen chromosomale Veränderungen unterdrücken, kann angenommen werden, dass bei der Hefe ein wesentlicher Teil der Zellinaktivierung infolge Röntgenbestrahlung auf chromosomalen Störungen beruht.
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    Cellular and molecular life sciences 9 (1953), S. 384-385 
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    Notes: Summary The application of monosemicarbazon derivate of Adrenochrom (Adrenoxyl) indicates a muscle-active effect (decrease of contraction and retardation of muscle tiredness) in rats, in rabbits and in man.
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    Cellular and molecular life sciences 9 (1953), S. 380-381 
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    Notes: Summary Using paper electrophoresis, the author found that when human hemoglobin is added to human sera, it is captured by a fraction of theα 2-globulin, which results in a compound with an electrophoretic mobility between that ofα 2-globulin andβ-globulin. He identifies this fraction of theα 2-globulin with the haptoglobin discovered byJayle. This phenomenon may influence the estimation ofα 2-globulin even in slightly hemolytic sera.
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    Cellular and molecular life sciences 9 (1953), S. 379-380 
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    Notes: Summary The storage of anticoagulant Xylane sulfuric acid esters, as tested by the radioactivity of compounds containing S35, is of an extremely long duration. After three weeks the quantity found in the liver is the same as that found after 48 h. Additional dosage results in further accumulation. Heparin is no exception since it behaves as Xylane sulfuric acid ester of the same viscosity and sulfur content.
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    Cellular and molecular life sciences 9 (1953), S. 381-384 
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    Notes: Zusammenfassung Experimentell wird gezeigt, dass Heinzsche Körper durch niedere Konzentrationen von Natriumazid und 2:4-dichlorphenol gebildet werden. Diese Substanzen hemmen Katalase stark, und es wird angenommen, dass die Katalasehemmung die erste Stufe beim Abbau von Hämoglobin und anderer Zellbestandteile ist. Dies führt zur Bildung von Heinzschen Körpern.
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    Cellular and molecular life sciences 9 (1953), S. 389-389 
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    Notes: Summary A modification of the automicroradiograph technique with collodion emulsions is given.
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