bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hypertrophy versus Hyperplasia
Authors: Goss Richard J. 
Published: October 2006

Although all tissues and organs of the body are normally subject to the growth-regulating influences of functional demands, some are potentially capable of unlimited growth while others are not. This depends on whether hyperplasia of their functional units ceases prior to maturity or can continue throughout life. In the former case, further growth is limited by the extent to which hypertrophy can enhance physiological efficiency. Some of the body's most vitally essential organs (heart, brain, kidney, lung) lack the ability to make additional structural units in the adult and are therefore handicapped in compensating for the depreciations of advancing age. Theoretically, at least, other organs (glands, renewing tissues) possess unlimited powers of regeneration because they never lose the capacity (latent or expressed) for hyperplasia.
There is a strategy in the way growth mechanisms have evolved. It may be significant that the so-called "hypertrophic" organs lose the capability for hyperplasia, because not to do so might jeopardize their growth regulation. If size is determined by functional demands, then the latter must not operate continuously lest growth go on without interruption and lead to overproduction of functional units. Only renewing tissues can tolerate perpetual growth because they get rid of excess structures as fast as they are formed. Endocrine and exocrine glands are in most cases known to function discontinuously and are thus not in danger of being overstimulated. The heart, lungs, and kidneys (and brain?), however, must work incessantly. Were their functional units capable of hyperplasia and at the same time subject to control by functional demand, then overgrowth would seem to be inevitable. By giving up the potential for hyperplasia in favor of the necessity for constant function, these organs have adopted a strategy that enables them to become hypertrophic to a limited extent while doing their jobs efficiently.
It is a curious fact that the unrestricted proliferation of biological structures cannot occur at all levels of organization. The counterpart of cancer, which is a cellular phenomenon, does not exist among molecules or cytoplasmic organelles, nor is it known to occur at the histological level of organization. Even in organs made up of histological units of function and having the potential for unlimited hyperplasia (for example, liver, exocrine glands, thyroid, ovary), the population of functional units never exceeds the number needed to fulfill the physiological requirements of the body. Above and below the level of the cell, therefore, structures are not permitted to escape the constraints of functional demands which control their production. The fact that cells can occasionally do so when they become neoplastic may reveal as much as it conceals about the problem of growth regulation.
Privacy and Behavioral Research
Authors:   Panel on Privacy and Behavioral Research
Published: October 2006

From our examination of the relation of behavioral science research to the right to privacy, we have been led to the following conclusions.
1) While most current practices in the field pose no significant threat to the privacy of research subjects, a sufficient number of exceptions have been noted to warrant a sharp increase in attention to procedures that will assure protection of this right. The increasing scale of behavioral research is itself an additional reason for focusing attention in this area.
2) Participation by subjects must be voluntary and based on informed consent to the extent that this is consistent with the objectives of the research. It is fully consistent with the protection of privacy that, in the absence of full information, consent be based on trust in the qualified investigator and the integrity of his institution.
3) The scientist has an obligation to insure that no permanent physical or psychological harm will ensue from the research procedures, and that temporary discomfort or loss of privacy will be remedied in an appropriate way during the course of the research or at its completion. To merit trust, the scientist must design his research with a view to protecting, to the fullest extent possible, the privacy of the subjects. If intrusion on privacy proves essential to the research, he should not proceed with his proposed experiment until he and his colleagues have considered all of the relevant facts and he has determined, with support from them, that the benefits outweigh the costs.
4) The scientist has the same responsibility to protect the privacy of the individual in published reports and in research records that he has in the conduct of the research itself.
5) The primary responsibility for the use of ethical procedures must rest with the individual investigator, but government agencies that support behavioral research should satisfy themselves that the institution which employs the investigator has effectively accepted its responsibility to require that he meet proper ethical standards.
6) Legislation to assure appropriate recognition of the rights of human subjects is neither necessary nor desirable if the scientists and sponsoring institutions fully discharge their responsibilities in accommodating to the claim of privacy. Because of its relative inflexibility, legislation cannot meet the challenge of the subtle and sensitive conflict of values under consideration, nor can it aid in the wise decision making by individuals which is required to assure optimum protection of subjects, together with the fullest effectiveness of research.
A Multiple Origin for Plastids and Mitochondria
Authors: Raven Peter H. 
Published: October 2006

The impressive homologies between mitochondria and plastids, on the one hand, and procaryotic organisms, on the other, make it almost certain that these important cellular organelles had their origin as independent organisms. The vast number of symbiotic relationships of all degrees of evolutionary antiquity which have been found in contemporary organisms point to the ease with which such relationships can be established.

In view of this, the similarities between such totally different groups as blue-green algae and red algae, dinoflagellates and brown algae, and green algae and euglenoids can best be explained by postulating an independent, symbiotic origin of the plastids in each instance. A minimum of three groups of photosynthetic procaryotes appears to be necessary to explain the relationships among contemporary Protista and green plants: (i) the blue-green algae, which possess chlorophyll
a
, carotenoids, and phycobilins; (ii) the "green procaryotes," a hypothetical group characterized by chlorophylls
a
and
b
and a distinctive assemblage of carotenoid accessory pigments, but not phycobilins; and (iii) the "yellow procaryotes," a second hypothetical group whose members had chlorophylls
a
and
c
and various carotenoids but not phycobilins. There is, however, no reason to think that only three kinds of organisms were involved; numerous symbiotic events presumably occurred in each of these lines.

The "green procaryotes" and "yellow procaryotes" survive today only as chloroplasts from which the characteristics of the original, free-living forms can be deduced only in part. Hybridization between selected plastid DNA's may be helpful in unraveling this story, and is likewise suggested as the key to understanding the relationship between the blue-green algae and the chloroplasts of the red algae and cryptomonads.
It is postulated that the symbiotic organisms have lost various functions to the nucleus in the course of evolutionary time. If mitochondria and plastids have had a multiple origin, as suggested here, it will be necessary to examine the division of function between the two subsets of DNA for a wide variety of organisms before valid conclusions can be obtained.
Measurement Structures and Psychological Laws
Authors: Krantz David H. 
Published: October 2006

Empirical laws in psychology may be based on physical measurements (for example, voltages, times), counting, ordering, or just classifying. It is a pointless, though widespread practice to use a physical measure or a count as a "definition" of a psychological variable; this practice obscures the fact that all one has done is measured a physical variable, or counted. What is important are the empirical laws that are established by use of such quantitative or qualitative observations. Some kinds of empirical relations and laws yield measurement structures, akin to the qualitative structures underlying fundamental measurement in physics. Measurement structures are empirical structures that can be described most simply by introduction of a new numerical function; such a function is a new measure, and is typically interpreted as measuring some particular psychological variable.
Measurement structures, formulated abstractly, sometimes provide valuable tools for formulating new empirical hypotheses to be tested; but in many instances, other kinds of theory may be more appropriate. The main focus of research ought always to be the discovery of simple laws; these may or may not lead to new measures.
Capillary Tube Scanning Applied to Cell Growth Kinetics
Authors: Braslow Nelson M. , Bowman Robert L. 
Published: October 2006

We have developed an optical scanning instrument which may become a valuable aid in a variety of cell studies. Cell multiplication can be readily monitored with the instrument. By varying the chemical environment in which the cells are tested, questions of research and clinical interest may be quickly and conveniently answered. It appears possible to investigate the chemotherapeutic value of experimental agents, and to scan the sensitivity of a given population of neoplastic cells to a variety of chemotherapeutic agents at several concentrations. The optical scanning system may also be used to investigate certain metabolic pathways of cells in tissue culture, to determine drug resistance, and to assess the effects of medium composition on cell growth.
Our studies of BrdU resistance in mouse lymphoma cells were done primarily to demonstrate the potential of this optical scanning method, and we do not intend to continue the cytokinetic studies at present. We trust that others will be stimulated to investigate further applications of this instrumental approach to problems in cell biology.
Hurricane Prediction: Progress and Problem Areas
Authors: Simpson R. H. 
Published: October 2006

The subjective approach to hurricane prediction of yesteryear has given way to the automation of many facets of prediction, leaving the forecaster with more time to reason dynamically in making the final adjustments to the official track derived from a hierarchy of computer-generated guidances. The most important task immediately ahead is to develop and apply better diagnostic procedures to help the forecaster identify the guidance sources which are most likely to contain the truth, and to help assure that his final decision will either succeed or fail safely.
The ultimate prediction method for both hurricane development and movement will probably need to simulate not only the circulation of the hurricane but the interaction of the cloud clusters in its vortex with the large-scale environment. Assuming that this can be effectively done, the most important further handicap will be the problem of describing the initial conditions.
The development of a model which will dependably simulate the behavior of the three hurricanes in ten that turn out to be bad actors will not likely become operational in the near future. The most troubling problem in applying such a model—and it would have to be tested for years over a range of many storm types and conditions before becoming fully operational—is that the more complex the model is the more inscrutable the results are and the more difficult it becomes to identify the condition in which computational failure is probable. It would appear, therefore, that engineering approaches to prediction and diagnostic procedures of evaluation will dominate the methodology of hurricane forecasting for a number of years to come.
Female Steroid Hormones and Target Cell Nuclei
Authors: O'Malley Bert W. , Means Anthony R. 
Published: October 2006

The data discussed herein demonstrate the great variation in target-tissue response that can occur after administration of steroid hormones. The female sex steroids can exert regulatory effects on the synthesis, activity, and possibly even the degradation of tissue enzymes and structural proteins. Each response, nevertheless, appears to be dependent on the synthesis of nuclear RNA. In many instances, the steroid actually promotes a qualitative change in the base composition and sequence of the RNA synthesized by the target cell, implying a specific effect on gene transcription. Most important is our direct quantitative evidence that sex steroids cause a net increase in the intracellular amounts of specific mRNA molecules in target tissues.
It thus appears that we are discovering a pattern of steroid hormone action which includes: (i) uptake of the hormone by the target cell and binding to a specific cytoplasmic receptor protein; (ii) transport of the steroid-receptor complex to the nucleus; (iii) binding of this "active" complex to specific "acceptor" sites on the genome (chromatin DNA and acidic protein); (iv) activation of the transcriptional apparatus resulting in the appearance of new RNA species which includes specific mRNA's; (v) transport of the hormone-induced RNA to the cytoplasm resulting in synthesis of new proteins on cytoplasmic ribosomes; and (vi) the occurrence of the specific steroid-mediated "functional response" characteristic of that particular target tissue.
To elucidate fully the mechanism of steroid hormone action we must study the biochemistry of the process by which information held by the steroid hormone-receptor complex is transferred to the nuclear transcription apparatus. If our assumptions are correct, we should ultimately be able to discover how this hormone-receptor complex exerts a specific regulatory effect on nuclear RNA metabolism. Such regulation might be achieved (i) by direct effects on chromatin template leading to increased gene transcription and thus RNA synthesis; (ii) by activation of the polymerase complex itself; (iii) by inhibition of RNA breakdown; or (iv) by intranuclear processing of large precursor molecules so that smaller biologically active sequences are produced, and (v) by transport of RNA from the nucleus to the cytoplasmic sites of cellular protein synthesis.
Computerized Transaxial X-ray Tomography of the Human Body
Authors: Ledley R. S. , Di Chiro G. , Luessenhop A. J. , Twigg H. L. 
Published: October 2006

The ACTA-Scanner has virtually unlimited potential in the evaluation of any part of the body. The usefulness of the technique has already been shown in the appraisal of pathologies of the brain and cerebrospinal fluid cavities. The orbits and the eyeballs, the facial sinuses, and skull base lesions have also been elucidated.
Tumors of the larynx, pharynx, thyroid, and parathyroid; lymphomas; and pathology of the spine and spinal cord are well within the reach of this new diagnostic methodology. Lung pathologies, such as emphysema, pneumonias, neoplasms, infarctions, pleural effusions and granulomatous diseases, and mediastinal pathology represent a challenging complex of lesions to be appraised by ACTA-scanning. For the heart, there is great potential for observing cardiac chamber size, hypertrophy of ventricular or atrial walls, and ventricular or aortic aneurysms, and possibly for recognizing the damaged myocardial tissue immediately after or some time after an infarction. The abdominal pathologies that can be studied are almost uncountable: gastric neoplasms, pancreatic cysts and stones, gallstones, neoplasms of the liver and pancreas, bowel tumors, abdominal aortic aneurysms, renal neoplasms and cysts, atrophy of the kidneys, bladder tumors, uterine tumors, ovarian cysts, and many more. Although bones and joints are adequately demonstrated by conventional x-ray techniques, there is no doubt that as the new technique is developed ACTA-grams will contribute significant information in the transverse plane, as well as in densitometric analyses.
The impact of ACTA-scanning will not be limited to the diagnostic area, but will extend, at least indirectly, to general patient management and to some aspects of medical economics as well. Risk-laden, technically complex, and costly diagnostic procedures, sometimes requiring lengthy hospitalization, will in some cases be eliminated. The simple, innocuous, and noninvasive ACTA-scanning can be performed on an outpatient basis. Repeated follow-up examinations should be easily accepted by the patients, considering that this diagnostic test is carried out without discomfort. The entire field of diagnostic radiology is on the verge of revolutionary changes.
Analysis of Living Tissue by Phosphorus-31 Magnetic Resonance
Authors: Burt C. Tyler , Glonek Thomas , Bárány Michael 
Published: October 2006

Nuclear magnetic resonance is a new method for assaying the content of phosphate metabolites in intact tissues. Its nondestructive nature allows simultaneous and repeated determinations of these compounds with a minimum perturbation of tissue. Changes in the concentrations of the phosphates as a function of time characterize the metabolic machinery of the tissue and reveal alterations in enzymic activity that result from drug treatment or disease.
The entire phosphate profile shows differences between normal and diseased muscle which should be of diagnostic value. Further, by examining phosphate profiles we detected a family of chemical compounds that were not previously known to exist as major constituents in muscle. Of these, two have been isolated and one has been identified as glycerol 3-phosphorylcholine.
Finally, shifts in the positions of resonances monitor the internal environment of the living system, its hydrogen ion concentration, the complexing of alkaline earth metals with ATP, and compartmentalization within the cell.
Droplet Chondrules
Authors: Kieffer Susan Werner 
Published: October 2006

I have proposed that droplet chondrules were formed by jetting during collision of meteoritic particles with diameters ranging in order of magnitude from 0.5 mm to 20 cm. This conclusion, based on a dynamic model for the collision process, supports the hypotheses of Wasson (based on geochemical considerations) and Whipple and Cameron (based on dynamic model considerations) that chondrules were formed from objects less than 1 m in radius.
In this model, the formation of chondrules is viewed as a textural, but not substantial chemical, change in the material of the early solar system. Droplets of melt produced by jetting are mixtures of material derived from two parent grains. Jets are probably not appreciably fractionated (except in volatile elements) either in the short duration of the shock events (several microseconds) or in subsequent cooling.
This model for the formation of droplet chondrules implies that they were formed at a time in the history of the solar system when particle sizes were small. The most likely time for this condition is early in the process of accretion of nebular dust to planetary matter. Since velocities less than approximately 1.5 km/sec are required for the agglomeration and accretion of particles, the relatively higher velocities indicated for droplet chondrule-forming collisions indicate an early high-velocity destructive epoch amidst the general trend toward accretion of material.
A System of "Definitive Units" Proposed for Universal Use
Authors: Campbell George A. 
Published: October 2006

It is proposed that physicists discard the CGS and Heaviside units, which are responsible for much confusion and needless mental effort, and employ exclusively a single system of "definitive units." The units suggested include the international meter, the international kilogram, the second, the mechanical watt, the international mercury ohm and they conform with the other international units as closely as is compatible with self-consistency. The system is not only definite and absolute, but also comprehensive, readily visualized and, in large part, already employed under well-established names. The system was proposed in 1901 by Giorgi and in 1904 by Robertson but received scant attention on account of the artificial prestige of the CGS system. A single universal system of units should be the ultimate goal, and the "definitive units" are chosen with a view to their adoption not only by all scientists but also by the butcher, the baker and the candlestick-maker.
The definitive system of units makes it perfectly feasible to employ a single system much more generally than has ever been the case in the past; the natural ultimate goal is the universal use of these units for all purposes. In the attempt to extend the application of metric units in the United States the meter-stere-kilogram, rather than the meter-liter-gram, should form the basis for legislation, in order to give definitive units their proper legalized status and to secure to the full the advantages of a comprehensive system consistently interrelated with the legalized international electrical units. The gradual discarding of CGS and other redundant units would inevitably follow. Even in the absence of official recognition of definitive units, individuals may advantageously employ the system. This would cause confusion neither to authors nor readers, since these units, in the main, have already acquired vital existence through world-wide, daily use under familiar, well-established names.
Studies on the Fate of Plasma Prothrombin
Authors: Andrus William DeW. , Lord Jere W. , Kauer Joseph T. 
Published: October 2006

The level of the plasma prothrombin in the circulating blood is decreased during its passage through the pulmonary capillaries. In 85 per cent. of samples, plasma prothrombin has been found to be less in the blood of the left ventricle than in that from the right ventricle. This difference averaged 10.6 per cent. and ranged from 4 to 19 per cent. In no instance was the level in the right ventricle lower than that in the left. In samples of blood taken from the arterial and venous supply of the head, liver, spleen, intestine, kidney and hind limbs, no significant difference in plasma prothrombin levels was found.
A possible explanation of this role of the lung in the loss of plasma prothrombin is thought to be the production of blood platelets in this organ, as demonstrated by Howell and Donahue. Platelets, as they undergo disintegration, initiate the first stage of the clotting process by releasing thromboplastin, which, in the presence of calcium, changes prothrombin to thrombin.
A Study of Hormonal Factors Which Influence the Production of Insulin
Authors: Funk Casimir , Chamelin I. M. , Wagreich Harry , Harrow Benjamin 
Published: October 2006

1. Insulinotropic effects were obtained with a protein fraction of the anterior pituitary, with estradiol and with stilbestrol.
2. Varying diabetogenic effects were obtained with highly purified prolactin preparations, with progesterone, with testosterone and with a fraction, probably also protein, from the anterior pituitary.
Observations on the Biological Value of a Mixture of Essential Amino Acids
Authors: Albanese Anthony A. , Irby Virginia 
Published: October 2006

(1) A mixture of "essential" amino acids, fed to rats, was found to be inferior from a nutritional point of view to enzymatic or acid casein hydrolysates or casein fed at comparable levels.
(2) Evidence is presented which suggests that the nutritive inadequacy of the essential amino-acid diet may be due in part to toxic effects of unnatural forms of certain amino acids that can not be utilized.