bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fuel price increase, subsidies, overcapacity, and resource sustainability
Authors: Sumaila Ussif Rashid , Teh Louise , Watson Reg , Tyedmers Peter , Pauly Daniel 
Published: May 2008

Abstract
Sumaila, U. R., Teh, L., Watson, R., Tyedmers, P., and Pauly, D. 2008. Fuel price increase, subsidies, overcapacity, and resource sustainability. – ICES Journal of Marine Science, 65: 832–840. Global fisheries are currently overcapitalized, resulting in overfishing in many of the world’s fisheries. Given that fuel constitutes a significant component of fishing costs, we expect recent increases in fuel prices to reduce overcapacity and overfishing. However, government fuel subsidies to the fishing sector reduce, if not completely negate, this positive aspect of increasing fuel costs. Here, we explore the theoretical basis for the expectation that the increasing fuel prices faced by fishing enterprises will reduce fishing pressure. Next, we estimate the amount of fuel subsidies to the fishing sector by governments globally to be in the range of US$4.2–8.5 billion per year. Hence, depending on how much of this subsidy existed before the recent fuel price increases, fishing enterprises, as a group, can absorb as much as this amount of increase in their fuel budget before any conservation benefits occur as a result of fuel price increases.
Making Solutions from Dry Chemicals
Authors: Adams Dany Spencer 
Published: May 2008

INTRODUCTIONSolution making most typically involves dissolving a dry chemical in water or other specified solvent. The amount of chemical to be added to a solvent depends on the final concentration or molarity (M) needed for the finished solution and the total amount in liters (L) of solution required. The easiest way to measure chemicals is by mass. Typically, to make a solution one must determine the mass of chemical needed, based on the desired final concentration (usually molarity), the molecular weight (MW) of the chemical, and the final volume of solution. This article describes the calculations involved in making solutions from dry chemicals.
Making Solutions from Hydrated Compounds
Authors: Adams Dany Spencer 
Published: May 2008

INTRODUCTIONSolution making typically involves dissolving dry chemicals in water or other specified solvent. The amount of chemical to be added to a solvent depends on the final concentration or molarity (M) needed for the finished solution and the total amount in liters (L) of solution required. However, some chemicals come with water molecules attached. The molecular weight (MW) of such compounds, listed as formula weight (FW) on the bottle, includes the mass of the water. Whenever you would use the MW of an unhydrated compound in calculations, use instead the MW of the hydrated compound. If a recipe tells how many grams to use of the unhydrated compound, determine the target concentration and then calculate the grams to use of hydrated compound. When using a hydrated compound, the attached water molecules contribute water to the solution, potentially diluting the final concentration (if the solvent is water). Therefore, you must account for the contribution of water from the hydrated compound when determining the volume of solvent (water) to add. This article describes the calculations involved in making solutions from hydrated compounds.
Alkaline Phosphatase Treatment of Phosphopeptides: In-Solution Dephosphorylation prior to MALDI-MS Analysis
Authors: Steen Hanno , Stensballe Allan , Jensen Ole N. 
Published: May 2008

INTRODUCTIONThe use of the enzyme alkaline phosphatase allows identification of phosphopeptides in a mixture of predominantly nonphosphopeptides. Using a MALDI-MS instrument, the masses of peptides are acquired both before and after alkaline phosphatase treatment, which removes phospho-moieties from serine, threonine, and/or tyrosine. (Any peptide whose mass decreases by 80 Da, or a multiple thereof, is a phosphopeptide.) An advantage of using MALDI-MS for these experiments is that the peptide ions produced tend to be singly charged rather than multiply charged (as with ESI), thus making the interpretation easier. This protocol describes a method for in-solution dephosphorylation prior to MALDI-MS analysis.
Mapping Protein Distributions on Polytene Chromosomes by Immunostaining
Authors: Paro Renato 
Published: May 2008

INTRODUCTIONThe formidable size and structure of polytene chromosomes allow mapping of chromosomal protein distributions at very high resolution. This protocol describes the preparation of polytene chromosomes from Drosophila larvae, immunostaining of the chromosomes with a protein of interest, and counterstaining with Giemsa and Hoechst.
THE ROLE OF GLUCOCORTICOID HORMONES IN THE CONTROL OF EPIDERMAL MITOSIS
Authors: Bullough William S. , Laurence Edna B. 
Published: May 2008

ABSTRACTIt has previously been established that the epidermal chalone inhibits epidermal mitotic activity more powerfully in the presence of adrenalin, although adrenalin itself is not a mitotic inhibitor. It is now shown that in low concentrations hydrocortisone has little if any antimitotic activity, that when it is present together with chalone and adrenalin it does not markedly increase their antimitotic activity, but that it does act to prolong the mitotic depression which they induce.It is known that, without hydrocortisone, adrenalin rapidly escapes from epidermal cells so that the chalone action is weakened. It appears that the role of hydrocortisone may be to reduce the rate of adrenalin loss and thus to prolong the chalone‐adrenalin activity.It is also shown that the rate of loss of adrenalin from epidermal cells is inhibited, though to a much lesser extent, in the presence of excess chalone.
TOPOGRAPHY OF DNA SYNTHESIS IN THE MAMMARY GLAND OF THE C3H MOUSE AND ITS CONTROL BY OVARIAN HORMONES: AN AUTORADIOGRAPHIC STUDY
Authors: Bresciani Francesco 
Published: May 2008

ABSTRACTTritium‐labelled thymidine was injected 45 min before sacrifice into virgin female C3H/HeJ mice 7–23 weeks of age, as well as into 10‐week‐old mice which had been ovariectomized and treated daily with 1 μg of oestradiol‐17β and/or 1 mg of progesterone. Autoradiographs were made of squash preparations of the mammary glands, stained by Feulgen's method. The following results were obtained: (1) During normal development of the gland, cells synthesizing DNA are abundant in terminal buds and virtually absent in duct epithelium. Hence ductal growth takes place by the addition of cells produced in the terminal end structures. (2) At 5–6 months, when mammary growth has ceased, a considerable number of cells synthesizing DNA can still be found in alveoli, though not in duct epithelium. Hence the alveolar cells constitute a renewal population in the adult virgin. Because they maintain the potentiality to divide, duct cells are a G0 population. (3) Ovariectomy results in arrest of DNA synthesis within 3–5 days. Both oestradiol and progesterone restore DNA synthesis in alveoli but only progesterone is able to induce DNA synthesis in duct epithelium, and the differentiation of terminal buds into alveoli. This finding provides an explanation for the resumed proliferation of duct cells in pregnancy. (4) The number of cells engaged in DNA synthesis varies considerably among identical structures within the same gland. This may be due either to synchrony of cell replication and/or to fluctuations of proliferative activity in the gland.
AGE‐DEPENDENT TOXIC PROPERTIES OF ACTINOMYCIN D AND X‐RAYS IN CULTURED CHINESE HAMSTER CELLS
Authors: Elkind M. M. , Sakamoto K. , Kamper C. 
Published: May 2008

ABSTRACTA comparative study was made of the toxic properties of actinomycin D and X‐rays using synchronized populations of Chinese hamster cells cultured in vitro. X‐irradiated cells are most resistant in the latter half of the DNA synthetic period (late S). While cells treated with actinomycin D appear to go through a survival maximum at the same age, they are most resistant after the completion of DNA synthesis; i.e. in G2 (or G2‐mitosis).In spite of these differences, we found that actinomycin D damage in late S cells interacts with X‐ray damage. Thus, a common locus for the site of actions of both agents is suggested which may be in or around the genome of a cell in view of the well‐known DNA binding properties of actinomycin D.
METHODS FOR COMPUTING LYMPHOCYTE KINETICS IN MAN BY ANALYSIS OF CHROMOSOMAL ABERRATIONS SUSTAINED DURING EXTRACORPOREAL IRRADIATION OF THE BLOOD
Authors: Sharpe Heather B. A. , Dolphin G. W. , Dawson K. B. , Field E. O. 
Published: May 2008

ABSTRACTData on lymphocyte kinetics may be derived in patients undergoing treatment by extracorporeal irradiation of the blood by studying chromosome aberrations induced in their lymphocytes; the aberrations are observed when the lymphocytes are stimulated by phytohaemagglutinin to divide in culture. Two methods of analysis are described, one depends on the total number of dicentrics scored, the other employs the dilution principle, regarding each lymphocyte bearing one or more aberrations as specifically labelled. Two parameters may be calculated: the mean residence time of lymphocytes in the blood and the size of the extravascular pool of lymphocytes in the body. In a patient with Hodgkin's disease, the mean residence time was found to be 4.7–7.5 min and the extravascular pool 800–1070 g.
CELL PROLIFERATION IN NEWLY TRANSPLANTED EHRLICH ASCITES TUMOR CELLS
Authors: Wiebel Friedrich , Baserga Renato 
Published: May 2008

ABSTRACT

Ehrlich ascites tumor cells collected from donor mice on the 5th day after inoculation were injected into the peritoneal cavity of new recipient mice.
Cell cycle times were drastically shortened by transplantation, for instance, the length of the cell cycle from 47 to 21.5 hr, and the duration of S from 26.5 to 16.5 hr.
Transplantation also caused a transient delay of cells in G2 followed by a rapid acceleration and produced an immediate increase in the number of cells in DNA synthesis by about 5–8%.
STUDIES OF HEMATOPOIESIS IN MURINE SPLEENS: SIGNIFICANCE OF HEMATOPOIETIC COLONIES FORMED ON THE SURFACE OF SPLEENS
Authors: Lewis J. P. , O'Grady L. F. , Trobaugh F. E. 
Published: May 2008

ABSTRACTConies of hematopoietic tissue are formed in spleens of lethally irradiated mice by the injection of small numbers of hematopoietic cells. Some of these colonies appear as surface colonies, others can be identified only in serial sections of the spleen. The present studies have related the number and cellular composition of total hematopoietic colonies in the murine spleen to their visual recognition on the splenic surface. These studies demonstrate that only 50% of the total colonies in a spleen are recognized as surface colonies and that of those colonies on the surface, approximately 80% contain erythroid elements. At least four factors play important roles in the recognition of hematopoietic colonies as splenic surface colonies: (1) dose of repopulating cells or hematopoietic stem cells injected into the irradiated animal; (2) location of colonies within the spleen; (3) size of colonies; and (4) cellular content of the colonies. These studies demonstrate that surface colony formation reflects primarily erythropoiesis and not total hematopoiesis.
REPOPULATION OF THE BONE‐MARROW STEM‐CELL COMPARTMENT AFTER IRRADIATION*
Authors: Silini G. , Elli R. , Siracusa G. , Pozzi L. V. 
Published: May 2008

ABSTRACTBone‐marrow repopulation has been followed as a function of time after a single whole‐body dose of 150 rads X‐rays to (C3H × C57B1)F1 hybrid mice. The number of nucleated cells per bone shaft has been estimated by direct counting and the number of progenitor cells by the exogenous spleen‐colony assay method. Vinblastine was also administered under various schedules of time and dose in an endeavour to distinguish between cycling and dormant cells in the progenitor pool.The depopulation of total marrow cells induced by Vinblastine proceeds at a comparable rate in irradiated and in normal mice. On the other hand, the depopulation of the colony‐formers is faster in irradiated than in normal animals. The data are interpreted to show that the fraction of cycling progenitor cells is larger in a haemopoietic tissue undergoing numerical expansion.
A CHARACTERIZATION OF THE BOUNDARY BETWEEN THE CYCLING AND RESTING STATES IN ASCITES TUMOR CELLS
Authors: Lala Peeyush K. , Patt Harvey M. 
Published: May 2008

ABSTRACTGrowth deceleration of an Ehrlich ascites tumor with increasing mass is associated with a prolongation of the cell cycle and a decline in the growth fraction. These effects are reversed upon transfer of cells from an older tumor into a new host. Studies were made to locate the stages at which a cell cycle could be suspended or resumed. Transplantation caused a prompt rise in both mitotic and flash H3TdR labeling indices. When all the cells in cycle including mitoses were prelabeled with H3TdR in older tumors, the fraction of labeled mitoses did not decline for a considerable period after transplantation into new hosts. This suggests that the early rise in mitoses is not due to a flow of resting (Go) cells from a G2 store (G2‐Go transition). It appears rather to be a reflection of a lag of the mitotic process relative to other stages during the initial readjustment of the cycle. A prompt rise in flash H3TdR indices in the transplants suggested cell entry into S from either a suspended GI (G1‐Go transition) or a suspended S (S‐Go transition). These possibilities were examined by relating micro‐spectrophotometric estimates of DNA to the cell cycle stage as revealed by H3TdR autoradiography. Since Go cells had DNA values corresponding to GI, it was concluded that decycling or recycling could occur only after mitosis and before DNA synthesis.
AN EVALUATION OF ERYTHROPOIESIS IN THE YOUNG RAT
Authors: Roylance P. J. 
Published: May 2008

ABSTRACTEstimates of the cell population kinetic parameters have been obtained for the erythroid cells of the young growing rat using the technique of labelled mitoses and these results have been analysed by a computer programme. The phases of the cell cycle for the proliferating cells have been shown to be of shorter duration than generally reported. Together with the differential cell count and initial labelling index these data have enabled estimates of the growth fraction, birthrate, flow rate, number of divisions and transit time to be determined for each compartment.
RECOVERY IN THE MOUSE SPLEEN AFTER SUBLETHAL IRRADIATION
Authors: Petrov R. V. , Koslov V. A. , Seslavina L. S. 
Published: May 2008

ABSTRACT1. CBA and C57B1 mice were exposed to LD50/30 doses of γ‐radiation and at intervals after irradiation the numbers of haemopoietic colony‐forming units (CFU) and of antibody‐producing cells in the spleen were determined.2. CFU repression was observed after transfer of non‐irradiated cells to hybrid recipients. However, this repression did not appear until 60 days after irradiation of the donor.3. The recovery after irradiation of the capacity to inactivate CFUs in spleen cell mixtures was studied. The results suggested that cells which produce 19S antibody are different from those which are reactive against foreign cells.
CELL PROLIFERATION IN THE RAT KIDNEY INDUCED BY FOLIC ACID
Authors: Threlfall G. 
Published: May 2008

ABSTRACTThe changes in proliferative activity of tubular epithelial cells of the rat kidney following a single injection of folic acid (250 mg/kg body weight) have been studied. Autoradiography with tritiated thymidine revealed a large increase in numbers of labelled cells, beginning at about 18 hr, in each of the three kidney zones examined. In the cortex the maximum increase in labelling index (16 times normal) was found at 36 hr whereas that of the outer medulla (34 times normal) occurred at 24 hr; there was no clearly defined peak in the inner medulla, values of up to 36 times normal being found between 24 and 96 hr. These changes were followed several hours later by similar changes in mitotic index in the corresponding zones. All the indices, except the mitotic index of the inner medulla, had returned to normal by 6 days. Comparison of the curves of labelling index and mitotic index in each zone indicated that the number of cells induced to synthesize DNA was approximately similar to the number of cells which subsequently underwent mitosis.A large increase was also found in the specific activity of DNA extracted from homogenates of whole kidneys from folic acid‐injected rats, again using tritiated thymidine as label. The increase began at about 18 hr, reached a maximum of 16 times normal at 32 hr and returned to normal by 6 days. These changes were similar to those of labelling index in the cortical zone.
THE KINETICS OF LYMPHOCYTE RECIRCULATION WITHIN THE RAT SPLEEN
Authors: Ford W. L. 
Published: May 2008

ABSTRACTThe migration of lymphocytes from the blood into the splenic pulp and the release of lymphocytes from the spleen into the blood was studied by isolating the rat spleen and perfusing it with 15 ml of recirculating, oxygenated blood.When thoracic duct lymphocytes labelled with tritiated uridine were added to the initial perfusate the concentration of these cells fell exponentially for 2–3 hr and then rose to a flat secondary peak. From this pattern it was inferred that small lymphocytes entered the spleen at a rate proportional to their instantaneous concentration in the perfusate, traversed the splenic pulp and re‐entered the perfusate with a minimum transit time of 2–3 hr. The rate of release of small lymphocytes from the spleen was not influenced by the prevailing concentration of small lymphocytes in the perfusate but probably reflected the rate of migration into the spleen over a period earlier than 2 hr before. The rate of exchange of small lymphocytes between the blood and the intact spleen in vivo was estimated to be about 84 × 106 cells/hr. The size of the intrasplenic pool of recirculating small lymphocytes was probably 400–500 × 106 cells. The rate of migration of small lymphocytes into the spleen was not affected by prior irradiation of the spleen donor. When either of two antigenic materials were added to the perfusate no inhibition of lymphocyte migration into the spleen was noted although the release of lymphocytes from the spleen was diminished by the addition of a large dose of sheep erythrocytes.
THE ACTION OF HYDROXYUREA ON MOUSE L‐CELLS*
Authors: Bacchetti S. , Whitmore G. F. 
Published: May 2008

ABSTRACTThe toxic and inhibitory properties of hydroxyurea (HU) have been studied in asynchronous and synchronized populations of mouse L‐cells. Hydroxyurea is a potent growth inhibitor and appears to be specifically lethal for cells which are in the early part of S phase at the time the compound is introduced. Cells in late S phase, G2, mitosis and G1 appear to progress normally around the cycle in the presence of the compound until they reach the G1/S boundary. There are indications that at least some G1 cells are able to enter the S phase even in the presence of the drug; however their flow into S is much slower than that of control cells and therefore they are killed at a slow rate. Upon prolonged exposure to the drug a second phase of more rapid killing is observed, beginning at about the time division would occur in uninhibited cells. Hydroxyurea exhibits a rapid and marked inhibition on DNA synthesis but its effect on RNA synthesis is much less pronounced and may be a consequence of the inhibition of DNA synthesis. The effects of hydroxyurea on cell viability and DNA synthesis can be partially prevented by the addition of deoxyribonucleosides which in sufficient concentration appear to compete temporarily with the drug. The fact that the protection is only temporary would appear to rule out the hypothesis that the primary mode of action of the drug is the inhibition of the reduction which converts ribonucleotides to deoxyribonucleotides. The data presented in this communication taken together with observations of other workers would appear to suggest that the effect of the drug may be directly on the DNA molecule.
THE EFFECT OF IRRADIATED PLASMA ON NORMAL HUMAN CHROMOSOMES AND ITS RELEVANCE TO THE LONG‐LIVED LYMPHOCYTE HYPOTHESIS
Authors: Scott David 
Published: May 2008

ABSTRACTThe persistence of unstable chromosome‐type aberrations in peripheral blood lymphocytes of irradiated individuals has led to the proposal that some lymphocytes survive for many years in vivo without undergoing mitosis (Fitzgerald, 1964). It has recently been shown, however, that plasma from irradiated individuals can induce chromosomal damage in cultures of normal blood lymphocytes (Hollowell & Littlefield, 1968) even when the plasma donors were irradiated 7 years earlier (Goh & Sumner, 1968). Goh (1968) has therefore suggested that ‘An alternate explanation to the “long‐lived cell” theory proposed by others…would be that a substance is produced or activated by total body irradiation and remains capable of affecting the chromosomes for extensive lengths of time'.The present results show that a lymphocyte chromosome‐breaking factor can be induced in the plasma of blood irradiated in vitro as well as in vivo. All of the aberrations induced by this ‘plasma factor’and those reported by other workers can be interpreted as being of the chromatid type. Before the long‐lived lymphocyte hypothesis can be brought into serious disrepute, it must be shown that the plasma factor can induce aberrations of the same type as persist after in vivo irradiation (i.e. unequivocal chromosome‐type aberrations, such as dicentrics and rings) and that these can be induced in vivo.
A SIMPLE COMPUTER SIMULATION MODEL FOR GROWING CELL POPULATIONS: ANALYSIS OF SYNCHRONIZED HELA CELL CULTURES
Authors: Tibaux G. , Firket H. , Hopper A. F. 
Published: May 2008

ABSTRACTA simple simulation model is presented for growing cell populations. It consists of various ‘classes’of cells (usually thirty) with different cell cycle durations. The cells of each class are distributed in ‘compartments’(thirty to fifty) with different ages. A ‘typical cell’of each compartment is chosen at random and its behaviour weighed according to the number of cells of the compartment.When the parameters for cycle phase durations (G2, S, G1 and M) obtained from Quastler‐Sherman curves on HeLa cell cultures are fed into the model and the initial distribution of cells is randomized according to the law of exponential growth, the model behaves as an exponentially growing culture with near stable values for the percentage of cells in the various phases of the cell cycle. The level of noise due to random sampling is not objectionable.The behaviour of the model is compared to that of HeLa cultures synchronized by two successive treatments with 2 mM thymidine. While a complete block of S gives very inadequate results, a slowing down of this phase to 25 or 30% of its original speed is enough to simulate all the modifications produced by the thymidine treatment on the cultures. It is not necessary to postulate any other effect.These biological conclusions are reached in spite of the simplicity of the system. The behaviour of the model stresses the fact that for simulating the actual behaviour of cell populations, some parameters of the cell cycle have to be known with considerable accuracy, others are less critical. The model is compared with other mathematical models of cell populations recently proposed and ways to improve it are discussed.
THE DURATION OF MITOSIS IN THE CRYPTS OF LIEBERKÜHN OF THE TERMINAL ILEUM OF THE ALBINO RAT
Authors: Clarke Rufus 
Published: May 2008

ABSTRACTThe duration of mitosis in the epithelium of the terminal ileum of the adult rat has been determined by counting normal mitotic figures, and colchicine‐metaphases, in Feulgen‐stained squashes of whole, micro‐dissected crypts of Lieberkühn. The duration, which depends on the morphological definition of mitosis adopted, was calculated to be 23 min.This value is similar to those determined by other authors using other methods, except in the case of tritiated‐thymidine autoradiography, where the reported duration of mitosis is considerably longer. The possibility that this is due to an effect of thymidine on mitosis is discussed.