bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE VISUAL FUNCTIONS OF THE COMPLETE COLORBLIND
Authors: Hecht Selig , Shlaer Simon , Smith Emil L. , Haig Charles , Peskin James C. 
Published: May 2004

1. The visual functions of a completely colorblind individual are compared with those of the normal. The sensibility distribution in the spectrum has a maximum at 520 mµ at all brightnesses and thus corresponds to rod vision alone. This is confirmed by studies of dark adaptation which show final thresholds like those usually found for rod vision. Dark adaptation, measured both centrally and peripherally in the retina, is a single continuous function, and regardless of the brightness of the preceding light adaptation, is of the rapid type only, such as that found for the normal following low light adaptation. Visual acuity also shows a single continuous function like that for rod vision.
2. Both critical fusion frequency and intensity discrimination show two sections, one at low and the other at high intensities with a sharp transition from one to the other. Intensity discrimination is as good as for the normal eye, and covers much the same range. The maximal critical fusion frequency is only about 20 cycles per second as compared to 55 cycles for the normal.
3. The two sections shown by the colorblind eye for intensity discrimination and fusion frequency possess the spectral sensitivity of rod vision since the relative positions on the intensity scale are not influenced by using different parts of the spectrum.
THE KINETICS AND THERMODYNAMICS OF REVERSIBLE DENATURATION OF CRYSTALLINE SOYBEAN TRYPSIN INHIBITOR
Authors: Kunitz M. 
Published: May 2004

Crystalline soybean trypsin inhibitor protein undergoes denaturation on heating which is reversed on cooling. In the range of temperature of 35 to 50°C. a solution of the protein consists of a mixture of native and denatured forms in equilibrium with each other. The equilibrium is only slowly established and its final value at any temperature is the same whether a heated, denatured solution of the protein is cooled to the given temperature or whether a fresh solution is raised to that temperature. The kinetics of reversible denaturation of the soybean protein as well as the reversal of denaturation is that of a reversible unimolecular reaction, each process consisting at a given temperature of the same two simultaneous reactions acting in opposite directions.
The experimental data on the effect of temperature on the velocity and the equilibrium constants of the opposing reaction were utilized in evaluating the reaction energies and activation energies.
The reaction energies for denaturation were found to be as follows:—
Change in total heat of reaction ΔH = 57,000 calories per mole
Change in entropy of reaction ΔS = 180 calories per degree per mole
The heat of activation ΔH1‡ for denaturation = 55,000
The heat of activation ΔH2‡ for the reversal of denaturation = –1900
The entropy ΔS1‡ for denaturation = 95
The entropy ΔS2‡ for reversal of denaturation = –84
DINITROCRESOL AND PHOSPHATE STIMULATION OF THE OXYGEN CONSUMPTION OF A CELL-FREE OXIDATIVE SYSTEM OBTAINED FROM SEA URCHIN EGGS
Authors: Crane Robert K. , Keltch Anna K. 
Published: May 2004

1. A cell-free system capable of using oxygen with oxalacetate as substrate has been prepared from both unfertilized and fertilized sea urchin eggs. The oxygen uptake by this system is about twice that of an equivalent quantity of intact unfertilized eggs and half that of an equivalent quantity of intact fertilized eggs.
2. The oxygen consumption of this cell-free oxidative system can be stimulated by addition of suitable concentrations of 4,6-dinitro-o-cresol or by inorganic phosphate. This confirms, with a cell-free system obtained from sea urchin eggs, the observations of Loomis and Lipmann regarding stimulation of oxygen consumption by a system obtained from rabbit kidney.
3. A preliminary but unsuccessful attempt has been made to determine the conditions under which cell-free, aerobic, phosphorylating systems may be obtained from either unfertilized or fertilized sea urchin eggs.
THE LOCI OF ACTION OF ULTRAVIOLET AND X-RADIATION AND OF PHOTORECOVERY IN THE EGG AND SPERM OF THE SEA URCHIN ARBACIA PUNCTULATA
Authors: Blum Harold F. , Robinson J. Courtland , Loos Gordon M. 
Published: May 2004

Various experiments are described which show the locus of action of ultraviolet radiation and of x-ray in delaying cell division of the fertilized egg of Arbacia punctulata to be in the nucleus.
Photorecovery following ultraviolet radiation has its locus in the egg cytoplasm.
Analogy is drawn with the action of ultraviolet radiation and photorecovery on the E. coli-bacteriophage system, and certain suggestions are made regarding a common mechanism.
Photorecovery after x-ray exposure could not be demonstrated.
DELAYED HEMOLYSIS OF HUMAN ERYTHROCYTES IN SOLUTIONS OF GLUCOSE
Authors: Hendry Edward B. 
Published: May 2004

There has been described a type of hemolysis which occurs under certain defined conditions when erythrocytes are suspended in glucose solution. It consists of a prolytic phase lasting about an hour, followed by a hemolytic phase lasting about 2 hours. The physical factors controlling this delayed hemolysis have been investigated. The system is especially sensitive to changes of pH and of temperature.
This type of hemolysis is inhibited by increased osmotic pressure and by phlorhizin, but not, as far as can be ascertained, by fluoride or iodoacetate.
It is possible, but not yet proved, that delayed hemolysis in glucose solution is dependent on enzymic activity. Phosphorylation may be the limiting factor.
During the prolytic phase the cells are easily permeable to potassium. It is concluded that the development of cation permeability is not a direct cause of hemolysis.
PREPARATION, PURIFICATION, AND PROPERTIES OF E. COLI VIRUS T2
Authors: Herriott Roger M. , Barlow James L. 
Published: May 2004

1. A method for the preparation of 8 to 10 liter quantities of T2 virus lysates, titering 2 to 5 x 1011 infectious units per ml. has been described.
2. Procedures have been developed for the concentration and purification of virus to a high specific infectivity. No fractionation procedure of the several used succeeded in further raising the specific infectivity of these purified preparations.
3. Some of the general properties of the better preparations have been determined. They exhibited titers of 2 x 1015 infective units per gm. of material or 1.2 x 1016 per gm. of nitrogen.
4. A study of the distribution of nitrogen among the various fractions of the virus showed that about 6 per cent of the total nitrogen is soluble in 4 per cent trichloracetic acid; that the protein nitrogen is about 40 per cent of the total and the nucleic acid nitrogen is 53 per cent. At least 96 per cent of the total phosphorus is in the nucleic acid fraction. Less than 0.5 per cent quantities of lipid and PNA were found.
THE ACTION OF VENOM AND PROTEOLYTIC ENZYMES ON THE NON-SPECIFIC INHIBITOR OF HYALURONIDASE
Authors: Hadidian Z. 
Published: May 2004

1. It has been shown that a number of proteolytic enzymes and snake venom, in relatively small amounts, and within a wide range of pH variation, will restore hyaluronidase activity after its inhibition by serum.
2. The known properties of the venom protease are found to be identical with those of Haas' "proinvasin I." It is concluded that the protease of the venom offers adequate explanation for the effects previously attributed to "proinvasin I."
3. Proteolytic activity is found in hyaluronidase preparations of bovine origin and is considered to be responsible for the reversal of inhibition of hyaluronidase by serum.
MODIFICATION BY TEMPERATURE OF CONDUCTION AND GANGLIONIC TRANSMISSION IN THE GASTROPOD NERVOUS SYSTEM
Authors: Turner R. S. 
Published: May 2004

The pedal ganglia of the terrestrial gastropod Ariolimax contain junctions between nerve fibers which are shown to be preferential points of fatigue and which exhibit facilitation (summation) of preganglionic impulses to produce a postganglionic spike. These characteristics in conjunction with others previously reported (reversible susceptibility to nicotine, convergence of preganglionic impulses, and inhibition of transmission through setting up a refractory state in the postganglionic fiber) are considered sufficient to indicate synaptic transmission in the pedal ganglia.
The mean conduction velocity of the fastest fibers in the pedal nerves is 0.52 meter per second for preganglionic and 0.50 meter per second for postganglionic fibers at 7.56°C. The conduction rates at 21.76°C. are respectively 0.80 meter per second and 0.83 meter per second. The mean ganglionic delay is 0.033 second at 7.56°C. and 0.019 second at 21.76°C. The mean Q10's for conduction velocity are thus 1.37 for preganglionic and 1.42 for postganglionic fibers. The mean Q10 for ganglionic delay is 1.49. If the assumption is made that the Q10 for ganglionic delay is that of a limiting reaction, this figure then represents a value below which the Q10 for synaptic delay is statistically improbable.
THE CONVERSION OF FIBRINOGEN TO FIBRIN
Authors: Shulman Sidney , Katz Sidney , Ferry John D. 
Published: May 2004

1. Fibrin clots prepared in the absence of calcium can be dissolved in solutions of lithium chloride and bromide and sodium bromide and iodide, as well as of guanidine hydrochloride and urea. These salts do not denature fibrinogen under the same conditions of concentration, temperature, and time. Sedimentation experiments on the fibrin solutions show in each case a single sharp peak with a sedimentation constant close to that of fibrinogen.
2. At lower concentrations, these salts inhibit the clotting of fibrinogen by thrombin, but in the case of lithium bromide and sodium iodide, at least, allow an intermediate polymer to accumulate whose sedimentation constant is close to that of the polymer observed in systems inhibited by hexamethylene glycol or urea.
THE COMBINATION BETWEEN HEMOLYSINS AND RED CELLS OR GHOSTS, AS STUDIED WITH A RADIOACTIVE LYSIN AND WITH NEW COLOR REACTIONS
Authors: Ponder Eric , Ponder Ruth V. , Anderson R. Christian 
Published: May 2004

The quantity of a radioactive hemolysin, sodium dodecyl sulfonate-S35, taken up by red cells from concentrations too small to produce hemolysis varies with the lysin concentration, and does so in a way which can be described by an adsorption isotherm. Attempts to use color reactions or surface tension measurements to determine the quantity of digitonin, saponin, and the bile salts taken up by red cells from hypolytic concentrations have failed, principally because chromogenic, and also surface-active, substances are liberated from the cells when the lysin is added. Color reactions with the anthrone reagent show that digitonin and saponin are both taken up by or fixed to red cell ghosts; the extent of the uptake, however, is uncertain, again because of the liberation of chromogenic substances.
Comparison of the results of the various methods which measure the apparent amount of lysin fixed, or utilized in reactions between lysins and red cells or ghosts show discrepancies between results given by direct methods (measurement of radioactivity or of color) and indirect methods (addition of a second population after lysis of a first, and dependence of the position of the asymptote of the time-dilution curve on the number of red cells). The discrepancies are traceable to the inhibitory effects of substances liberated from the red cells or ghosts.
The ease with which a lysin, once taken up by red cells, can be detached by diluting the system determines the extent to which the hemolytic reaction is "progressive," but has no observed connection with the quantity taken up in the first place. There is now ample evidence that lysis in systems containing simple hemolysins is a process involving two stages in time and two phases, and that it is usually complicated by reactions between the hemolysin and liberated inhibitory material.
POTASSIUM UPTAKE BY THE DOG ERYTHROCYTE
Authors: Frazier Howard S. , Sicular Arthur , Solomon A. K. 
Published: May 2004

The inward transport of potassium by separated dog erythrocytes has been studied at concentrations of potassium in the medium from 2.9 to 25.0 m.eq./liter and at 38.0 and 33.0°C. At the physiological concentration of external potassium (4.06 m.eq./liter medium), the inward potassium flux is 0.11 m.eq./liter cells hour and the glucose consumption is 2.0 mM/liter cells hour. The dependence of potassium influx on extracellular potassium concentration is given by the following equation,
K influx (m.eq./liter cells hour) = 0.028 [K]amb. – 0.003
in which [K]amb. refers to the potassium concentration in the medium. In a single 93 hour experiment, 94 per cent of the intracellular potassium was exchanged at an apparently uniform rate. The average apparent activation energy for the process is 7,750 calories ± 2,000 calories/mol and there is some indication that the apparent activation energy of inward K transport decreases with increasing external K concentration.
ON THE ROLE OF THE SPINAL AFFERENT NEURON AS A GENERATOR OF EXTRACELLULAR CURRENT
Authors: Rudin Donald O. , Eisenman George 
Published: May 2004

The prediction that a system of currents flows between the dorsal column and the dorsal root due to differences in their after-potentials was found to be consistent with the experimental findings. The form, magnitude, duration, and sign of the electrotonic component DRα fulfill the requirements of the postulated system.
A contribution of tract after-potentials to the evoked potential of intramedullary structures is indicated.
It is a conclusion of this and previous studies that profound changes occur in certain membrane properties of myelinated primary afferent axons as they penetrate the central nervous system. The working concept of abrupt intraaxonal junctional regions is therefore justifiable.
HEXOKINASE ACTIVITY FROM EGGS OF THE SEA URCHIN ARBACIA PUNCTULATA
Authors: Krahl M. E. , Keltch A. K. , Walters C. P. , Clowes G. H. A. 
Published: May 2004

1. The hexokinase activity of homogenates of eggs and embryos of the sea urchin Arbacia punctulata has been measured. Expressed as micrograms glucose consumed at 20°C., per hour per milligram of protein the following values were obtained: unfertilized eggs, 67; fertilized eggs, 72; 24 hour plutei, 94; 48 hour plutei, 226. The concentration of the enzyme in the eggs is small and may be calculated to be about 0.001 per cent of the dry weight of unfertilized eggs.
2. The hexokinase activity of the egg homogenate was virtually all recovered in the supernatant fraction when the homogenate was centrifuged at 20,000 x g for 30 minutes and was found to have the following properties: The concentrations for half maximal hexokinase activity with various substrates were, approximately: Glucose, 0,00003 M; fructose, 0.00075; mannose, 0.00007; 2-desoxyglucose, 0.00025. The relative rates of phosphorylation of various sugars by the supernate fraction when saturated with substrate were, approximately: Glucose, 1.0; mannose, 1.2; fructose, 1.8; 2-desoxyglucose, 2.0; glucosamine, 0.6. Adenosinediphosphate and glucose-6-phosphate inhibited the enzyme. No evidence for more than one hexokinase in the Arbacia extracts was found.
INTERACTIONS BETWEEN MAGNESIUM, PYROPHOSPHATE, AND THE CONTRACTILE ELEMENTS
Authors: Bozler Emil 
Published: May 2004

1. If glycerol-extracted muscle fibers are alternately immersed in solutions of inorganic pyrophosphate (PP) or ethylenediamme tetraacetate (EDTA) and KCl two to three times, PP no longer increases extensibility. The original condition is restored by solutions containing Mg. EDTA prevents completely the softening action of PP, but has no effect in the presence of an excess of Mg. These observations are explained by assuming that PP and EDTA remove bound Mg. Evidently PP has no softening action without Mg.
2. If PP is washed out from muscle fibers by solutions containing Mg, the softening action of PP persists for many minutes, but washing out with KCl solution promptly abolishes the effect of PP. Also, if fibers which have been made refractory to PP are immersed into a solution of PP and then into a KCl solution free of PP for several minutes, the addition of MgCl2 alone increases extensibility. It is concluded that PP forms a complex with protein. The formation of this complex, however, has no influence on the mechanical properties, unless Mg also is present.
3. In the presence of PP and Mg the viscous resistance of muscle fibers drops with diminishing temperatures.
CHROMATOGRAPHY OF BLOOD-CLOTTING FACTORS AND SERUM PROTEINS ON COLUMNS OF DIATOMACEOUS EARTH
Authors: Milstone J. H. 
Published: May 2004

1. In batch adsorptions with prothrombin solutions, hyflo was the weakest adsorbent, standard super-cel intermediate, and filter-cel strongest. Of these three grades of diatomaceous earth, hyflo has the smallest surface area per gram and filter-cel the largest. In parallel breakthrough experiments, a column of standard super-cel had a capacity almost six times that of a hyflo column.
2. After partial removal of impurities by diatomaceous earth, prothrombin preparations contained less thrombokinase, were more stable, and displayed less tendency to form thrombin "spontaneously." Thrombokinase (or its precursor) was removed from a preparation of prothrombin by passage through a filter cake of standard super-cel. The specific activity of the prothrombin was increased; and 62 per cent of the activity was recovered.
3. Prothrombin was adsorbed from an ammonium sulfate solution at pH 5.26 by columns of hyflo or standard super-cel. When eluted by phosphate solutions, the protein moved down the columns more readily at higher pH and higher concentration of phosphate salts, within the pH range 5.0 to 6.6, and within the phosphate range 0.1 to 1.0 M.
4. Thrombin was adsorbed on a column of standard super-cel at pH 5.11. As successive eluents passed through the column, the thrombin emerged between two bands of impurities. The specific activity of the thrombin was raised; and 83 per cent of the activity was recovered.
5. With a column of standard super-cel, and with a series of eluents within the pH range 5.1 to 6.3, total serum proteins were separated into four major bands. About 94 per cent of the protein was recovered.
THE RELATIONSHIP BETWEEN CHLOROPHYLL AND THE CAROTENOIDS IN THE ALGAL FLAGELLATE, EUGLENA
Authors: Wolken J. J. , Mellon A. D. 
Published: May 2004

1. We have obtained an action spectrum for chlorophyll formation in Euglena gracilis. This action spectrum is similar to the absorption spectrum of protochlorophyll. However, efforts to isolate and identify this pigment have been unsuccessful.
2. Porphyrins have been extracted from both the normal and dark-adapted Euglena and a chlorophyll-free mutant.
3. The "action" spectra for chlorophyll and carotenoid synthesis have been found to almost coincide, indicating that the same porphyrin-like molecule may influence the synthesis of both pigments.
4. It is indicated that two porphyrin-like systems are in operation simultaneously, one concerned with carotenoid "removal" and another involved in carotenoid and chlorophyll synthesis.
THE PROTEIN COATS OR "GHOSTS" OF COLIPHAGE T2
Authors: Herriott Roger M. , Barlow James L. 
Published: May 2004

A method of preparing the protein coats or ghosts of phage T2 is described along with proof that the lytic action is a property of the ghost.
An assay based on the lytic action toward host cells has been developed which permits a rapid evaluation of the number of ghosts with a reliability of ±15 per cent.
The antigenic and certain physicochemical properties of the ghost have been determined.
THE CATION CONTENT OF PHOSPHOLIPIDES FROM SWINE ERYTHROCYTES
Authors: Kirschner Leonard B. 
Published: May 2004

Phospholipides from swine erythrocytes were isolated and separated into four reproducible fractions. One of the fractions seems to be pure phosphatidylserine. The others are almost certainly not single compounds, although the analytical data indicate that they represent mixtures considerably simpler than the parent mixture extracted from the cells.
All four fractions contained Na+ and K+, but very little Ca2+. Sodium was the predominant cation in two of the fractions under all conditions although the major intracellular cation was potassium. In the other two fractions the ratio Na/K varied with the extraction procedure largely because the quantity of K+ seemed to depend on the solvent system used. There appear to be reasons to believe that the entire system of phospholipides binds Na+ preferentially. In addition, it was observed that the quantity of Na+ found in the lipide extracts varied when the extrusion of Na+ from the cells was made to vary. Both of these observations are consistent with the possibility that the phospholipides play some part in the extrusion of Na+ from these cells.
Population Growth in Planaria Dugesia tigrina (Gerard)
Authors: Davison John 
Published: May 2004

Planaria reproduce by transverse fission. Isolated worms increase in number exponentially, while social animals at the same density are inhibited in terms of numerical increase, but over a 25 day period undergo a larger increase in mass. Isolated posterior fission products reproduce faster than isolated anterior fission products. Regulation of population growth is independent of density over a 16-fold range and regulatory factors cannot be demonstrated in the medium. Regulation of population growth depends on direct contact between animals. Fission period varies from individual to individual and from period to period for a given individual. Doubling time is related to the absolute number of individuals comprising the population as follows:
PN = (PM · N)/(K + N),
where PN is the doubling period of a population of N individuals, PM is the doubling time of an infinitely large population, N is the number of individuals in the population, and K is the number of individuals in a population the period of which is one-half PM. At 22°–24°C PM is estimated to be 43.3 days and K is 1.87 individuals. A model system assumes that inhibitor flows through the population from animal to animal from the slowest to the fastest animal in the population thus acting to synchronize population increase as well as to determine the rate of population growth. A possible source of the inhibitor is discussed.
Mixed-mean inequalities for subsets
Authors: Leng Gangsong , Si Lin , Zhu Qingsan 
Published: May 2004

For

A
⊂
X
=
{

x
1

,
.
.
.
,

x
n

|

x
i

≥
0
,

i
=
1
,
2
,
.
.
.
,
n
}
,

A\subset X=\{x_1,...,x_n ~|~x_i\geq 0, ~i=1,2,...,n\},

let

a
A

a_A

and

g
A

g_A

denote the arithmetic mean and geometric mean of elements of

A
A

, respectively. It is proved that if

k
k

is an integer in

(

n
2

,
n
]

(\frac {n}{2}, n]

, then
\[

(

∏

|

A

|

=
k

A
⊂
X

a

A

)

1

C
n
k

≥

1

C
n
k

(

∑

|

A

|

=
k

A
⊂
X

g

A

)

,

\Big (\prod _{|A|=k\atop A\subset X}a_{A}\Big )^{\frac {1}{C_n^k}} \geq \frac {1}{C_n^k}\Big (\sum _{|A|=k\atop A\subset X}g_{A}\Big ),

\]
with equality if and only if

x
1

=
.
.
.
=

x
n

x_1=...=x_n

. Furthermore, as a generalization of this inequality, a mixed power-mean inequality for subsets is established.