cssi/SciSciGPT-SciSciNet huggingface dataset:
The use of penicillin in oil and wax in children.

Penicillin in oil and wax was administered to 106 infants and children in a total of 510 single injections at 24 hour intervals as therapy for acute infections. The Clinical response was comparable to that seen with aqueous penicillin administered at more frequent intervals. From this study the following conclusions were reached. 1. The danger of local reaction is not great, as in only five cases there appeared urticarial lesions near the site of injection which seemed to cause no discomfort and which deared within 48 hours. There were no more serious reactions. 2. There is no satisfactory correlation between the size of dose per unit of body weight and the resulting blood level of penicillin 24 hours after injection. There is, however, a relation between the absolute dose and the resulting blood level. A dose of 300,000 units in all patients regardless of size produced a satisfactory level for the control of ordinary infections. 3. Both sodium and potassium salts were used. There is doubtful statistical evidence that the potassium salt produces higher levels at the end of 24 hours.
A PROSPECTIVE STUDY OF AGE AT MENARCHE, PARITY, AGE AT FIRST BIRTH, AND CORONARY HEART DISEASE IN WOMEN

To investigate the risk of coronary heart disease in relation to age at menarche parity and age at first birth the authors evaluated prospectively the experience of 119963 U.S. women aged 30-55 years who were free from coronary heart disease in 1976 and were followed through 1982. During 700809 person-years of observation 308 incident cases of nonfatal myocardial infarction or fatal coronary heart disease occurred. The results showed no significant association between reproductive experiences and risk of coronary heart disease. (EXCERPT)
Transport and posttranslational processing of the vacuolar enzyme α-mannosidase in jack-bean cotyledons.

α-Mannosidase (EC 3.2.1.24) is a vacuolar enzyme which occurs abundantly in the cotyledons of the jack-bean (Canavalia ensiformis (L.) DC). The mature enzyme is a tetramer with two polypeptides each of relative molecular mass (Mr) 66000 and Mr 44000. The enzyme has an interesting molecular structure because in its native form, it does not bind to concanavalin A (ConA) in spite of the presence of a high-mannose glycan. α-Mannosidase is synthesized in the developing cotyledons of jack-beans at the same time as the abundant proteins canavalin and ConA. The enzyme is synthesized as a precursor which has an Mr of 110000 and is associated with the endoplasmic reticulum (ER). Antibodies against the deglycosylated subunits cross-react with the Mr-110000 precursor. Processing of the precursor to the constituent polypeptides occurs posttranslationally, probably in the protein bodies. Immunocytochemical evidence shows that α-mannosidase is present in the ER and the Golgi complex of developing cells, and accumulates in the protein bodies. Labeling with [3H]glucosamine shows that after processing only the Mr-66000 polypeptide has glucosamine-containing glycans. The synthesis of these glycans is inhibited by tunicamycin, indicating that they are asparagine-linked oligosaccharides. Analysis of the glycans shows that there is a large glycan that is retained by ConA and a small glycan that is not retained by ConA. The large glycan is only partially sensitive to α-mannosidase because of the presence of a terminal glucose residue. Cross-reaction of the large subunit with an antiserum directed against small, complex glycans of plant glycoproteins indicates that this polypeptide probably has a xylose-containing glycan. Pulse-chase experiments carried out in the presence of tunicamycin show that the presence of glycans is not required for transport of α-mannosidase out of the ER-Golgi system.
The pressure‐volume‐temperature relationship and the heat of fusion of polyoxymethylene

The pressure-volume-temperature relation of polyoxymethylene was measured at pressures from 100 to 2000 kg/cm2 and from room temperature to 200°C. The dependence of the melting and crystallation temperatures on pressure was also determined. The unit cell parameters were measured up to 170°C by x-ray diffraction. These data were combined through the use of the Clapeyron equation to compute a heat of fusion of 92.9 cal/g. This value is considerably higher than those previously reported. The weight fraction crystallinity of an injection molded sample was 48% by calorimetry and 66% by interpolation between the specific volumes of the crystal and the amorphous phase. It is suggested that a simple two-phase model is inadequate to describe this polymer.
Increased visual sensitivity following periods of dim illumination.

PURPOSE We measured changes in the sensitivity of the human rod pathway by testing visual reaction times before and after light adaptation. We targeted a specific range of conditioning light intensities to see if a physiological adaptation recently discovered in mouse rods is observable at the perceptual level in humans. We also measured the noise spectrum of single mouse rods due to the importance of the signal-to-noise ratio in rod to rod bipolar cell signal transfer. METHODS Using the well-defined relationship between stimulus intensity and reaction time (Pieron's law), we measured the reaction times of eight human subjects (ages 24-66) to scotopic test flashes of a single intensity before and after the presentation of a 3-minute background. We also made recordings from single mouse rods and processed the cellular noise spectrum before and after similar conditioning exposures. RESULTS Subject reaction times to a fixed-strength stimulus were fastest 5 seconds after conditioning background exposure (79% ± 1% of the preconditioning mean, in darkness) and were significantly faster for the first 12 seconds after background exposure (P < 0.01). During the period of increased rod sensitivity, the continuous noise spectrum of individual mouse rods was not significantly increased. CONCLUSIONS A decrease in human reaction times to a dim flash after conditioning background exposure may originate in rod photoreceptors through a transient increase in the sensitivity of the phototransduction cascade. There is no accompanying increase in rod cellular noise, allowing for reliable transmission of larger rod signals after conditioning exposures and the observed increase in perceptual sensitivity.
'Shape effects' in metal oxide supported nanoscale gold catalysts.

We report the activity of shape-controlled metal oxide (CeO2, ZnO and Fe3O4) supported gold catalysts for the steam reforming of methanol (SRM) and the water gas shift (WGS) reactions. Metal oxide nanoshapes, prepared by controlled hydrolysis and thermolysis methods, expose different crystal surfaces, and consequently disperse and stabilize gold differently. We observe that similar to gold supported on CeO2 shapes exposing the {110} and {111} surfaces, gold supported on the oxygen-rich ZnO {0001} and Fe3O4 {111} surfaces shows higher activity for the SRM and WGS reactions. While the reaction rates vary among the Au–CeO2, Au–ZnO and Au–Fe3O4 shapes, the apparent activation energies are similar, indicating a common active site. TPR data further indicate that the reaction lightoff coincides with the activation of Au–O–M species on the surface of all three oxide supports evaluated here. Different shapes contain a different number of binding sites for the gold, imparting different overall activity.
A role for L-type calcium channels in the maturation of parvalbumin-containing hippocampal interneurons

While inhibitory interneurons are well recognized to play critical roles in the brain, relatively little is know about the molecular events that regulate their growth and differentiation. Calcium ions are thought to be important in neuronal development and L-type voltage gated Ca(+2) channels have been implicated in activity-dependent mechanisms of early-life. However, few studies have examined the role of these channels in the maturation of interneurons. The studies reported here were conducted in hippocampal slice cultures and indicate that the L-type Ca(+2) channel agonists and antagonists accelerate and suppress respectively the growth of parvalbumin-containing interneurons. The effects of channel blockade were reversible suggesting they are not the result of interneuronal cell death. Results from immunoblotting showed that these drugs have similar effects on the expression of the GABA synthetic enzymes, glutamic acid decarboxylase65, glutamic acid decarboxylase67 and the vesicular GABA transporter. This suggests that L-type Ca(+2) channels regulate not only parvalbumin expression but also interneuron development. These effects are likely mediated by actions on the interneurons themselves since the alpha subunits of L-type channels, voltage-gated calcium channel subunit 1.2 and voltage-gated calcium channel subunit 1.3 were found to be highly expressed in neonatal mouse hippocampus and co-localized with parvalbumin in interneurons. Results also showed that while these interneurons can contain either subunit, voltage-gated calcium channel subunit 1.3 was more widely expressed. Taken together results suggest that an important subset of developing interneurons expresses L-type Ca(+2) channels alpha subunits, voltage-gated calcium channel subunit 1.2 and especially voltage-gated calcium channel subunit 1.3 and that these channels likely regulate the development of these interneurons in an activity-dependent manner.
Nubp1 Is Required for Lung Branching Morphogenesis and Distal Progenitor Cell Survival in Mice

The lung is a complex system in biology and medicine alike. Whereas there is a good understanding of the anatomy and histology of the embryonic and adult lung, less is known about the molecular details and the cellular pathways that ultimately orchestrate lung formation and affect its health. From a forward genetic approach to identify novel genes involved in lung formation, we identified a mutated Nubp1 gene, which leads to syndactyly, eye cataract and lung hypoplasia. In the lung, Nubp1 is expressed in progenitor cells of the distal epithelium. Nubp1(m1Nisw) mutants show increased apoptosis accompanied by a loss of the distal progenitor markers Sftpc, Sox9 and Foxp2. In addition, Nubp1 mutation disrupts localization of the polarity protein Par3 and the mitosis relevant protein Numb. Using knock-down studies in lung epithelial cells, we also demonstrate a function of Nubp1 in regulating centrosome dynamics and microtubule organization. Together, Nubp1 represents an essential protein for lung progenitor survival by coordinating vital cellular processes including cell polarity and centrosomal dynamics.
The microphotohemolytic response of erythrocytes is altered by streptozotocin-induced diabetes and copper deficiency in rats

Abstract Microphotohemolysis is a new technique that has been used to determine the presence of alterations in the erythrocyte membrane. The method involves light activation through a microscope of a fluorescent dye-erythrocyte-buffer solution in a hemocytometer. The interaction of the light and dye result in the generation of toxic oxygen products which attack the membrane allowing water to enter the cell. As hemolysis occurs the optical density of the microscopic field decreases and this is recorded for later quantitation with an image analysis system. Maximal effect, time to half maximal effect and the slope of the hemolysis curve are determined. The goal of this study was to determine if microphotohemolysis could be used to detect differences in erythrocytes from animals with altered physiological states such as hypercholesterolemia, diabetes, and copper deficiency. These are conditions that alter the lipid or protein structure of the erythrocyte membrane and/or the antioxidative capacity of the erythrocyte. There were no effects of hypercholesterolemia on the microphotohemolytic response of the erythrocyte. Streptozotocin-induced diabetes resulted in a decreased maximum effect, a significant shift of the hemolysis curve to the right ( increased T 1 2 ) and a significant decrease in the slope of the hemolysis curve. Copper deficiency resulted in a significant decrease in the slope of the hemolysis curve. These results in diabetes and copper deficiency are consistent with an altered protein structure in the erythrocyte membrane that occurs in these conditions. The data demonstrate that this technique may be used to detect differences between normal and altered erythrocytes. As such, it could be useful in monitoring the course of a disease or its treatment.
Heat shock proteins Hsp70-1 and Hsp70-3 Are necessary and sufficient to prevent arsenite-induced dysmorphology in mouse embryos.

Heat Shock Proteins (HSPs) represent a variety of protein families that are induced by stressors such as heat and toxicants, and the induction of HSPs in the organogenesis stage rodent embryo is well established. It has been proposed that thermotolerance and chemotolerance result from expression of the HSPs. However, whether these proteins function to prevent dysmorphogenesis and which family members serve this function are unknown. Therefore, we evaluated the specific ability of stress-inducible Hsp70-1 and Hsp70-3 to prevent arsenite-induced dysmorphology in the cultured mouse embryo using gain- and loss-of-function models. Loss of HSP function was accomplished by injecting antisense oligonucleotides directed against hsp70-1 and hsp 70-3 mRNAs into the amniotic cavity of cultured Day 9 mouse embryos. Suppression of hsp70-1 and hsp70-3 expression resulted in an up to six-fold increase in the incidence of arsenite-induced neural tube defects. Gain of HSP function was accomplished by microinjecting a transgene with a constitutive promotor driving expression of the hsp70-1 coding region, and resulted in a decreased incidence of arsenite-induced neural tube defects. These results indicate that Hsp70-1 and Hsp70-3 are both necessary and sufficient for preventing arsenite-induced dysmorphology in early-somite staged mouse embryos. Mol. Reprod. Dev. 59:285–293, 2001. © 2001 Wiley-Liss, Inc.
Comparison of echocardiographic abnormalities in African-American, Hispanic, and White men and women aged >60 years

1. Grant J, Denne S. Effect of intermittent versus continuous enteral feeding on energy expenditure in premature infants. J Pediatr 1991;118:928–932. 2. Weir J. New methods for calculating metabolic rate with special reference to protein metabolism. J Physiol 1949;109:1–9. 3. Schoeller D, Ravussin E, Schulz Y, Acheson K, Baertschi P, Jequier E. Energy expenditure by doubly labeled water: validation and proposed calculation. Am J Physiol 1986;250:R823–R830. 4. Ackerman IL, Karn CA, Denne SC, Ensing GJ, Leitch CA. Total but not resting energy expenditure is increased in infants with ventricular septal defects. Pediatrics 1998;102:1172–1177. 5. Snider A. Echocardiography in Pediatric Heart Disease. Yearbook Medical Publishers, 1990. 6. Hamill P, Drizd T, Johnson C, Reed R, Roche A, Moore W. Physical growth: National Center for Health Statistics percentiles. Am J Clin Nutr 1979;32:607– 629. 7. Sann L, Durand M, Picard J, Lasne Y, Bethenod M. Arm fat and muscle areas in infancy. Arch Dis Child 1988;63:256–260. 8. Frisancho A. New norms of upper limb fat and muscle areas for assessment of nutritional status. Am J Clin Nutr 1981;34:2540–2545. 9. Tanner J, Whitehouse R. Revised standards for triceps and subscapular skinfolds in British children. Arch Dis Child 1975;50:142–145. 10. Feldt R, Strickler G, Weidman W. Growth of children with congenital heart disease. Am J Dis Child 1969;117:573–579. 11. Mehrizi A, Drash A. Growth disturbance in congenital heart disease. J Pediatr 1962;61:418–429. 12. Huse D, Feldt R, Nelson R, Novak L. Infants with congenital heart disease. Am J Dis Child 1975;129:65–69. 13. Cameron JW, Rosenthal A, Olson AD. Malnutrition in hospitalized children with congenital heart disease. Arch Pediatr Adolesc Med 1995;149: 1098 –1102.
Comparative biochemistry of pituitary gonadotropins

Abstract Except for some limited reports by Fontaine and Gerard and by Clemens et al. on the partial purification of gonadotropic or gonadal hydration factors present in the pituitary of the carp Cyprinus carpio , almost all experiments designed to purify and characterize pituitary gonadotropins have been carried out utilizing pituitaries from mammalian sources—sheep, cow, pig, horse, rat, rhesus monkey, and man. In addition, considerable effort has been expended in the purification of human urinary gonadotropins of pituitary origin. It has become evident from research on the mammalian gonadotropins, FSH, LH (or ICSH), and postmenopausal urinary gonadotropins, that they are all glycoproteins containing hexoses and hexosamines and small amounts of the methylpentose fucose. Sialic acid is apparently present in FSH, but not in LH; as shown by experiments with neuraminidase, it is required for the biological activity of FSH. Molecular weight measurements indicate values generally in the range of 25,000–30,000 for all these hormones in the physiological pH range. Recent experiments by Li, confirmed by Ward and his co-workers, have shown that in acid solution ovine LH can be dissociated into subunits with a molecular weight of approximately 15,000, indicating the presence of two chains of similar molecular weight making up the molecule existing at higher pH. Ward and his co-workers have demonstrated that the two chains are not identical since they possess different C-terminal amino acids. Similar findings have been made for the bovine hormone. Reactive N-terminal amino acids have been found only in trace quantities in any gonadotropic hormone preparation, suggesting that the amino groups are blocked (presumably by an acyl residue).
Self-Citation in Archaeology: Age, Gender, Prestige, and the Self

Citation analyses in archaeology have detected prestige tactics, shifts in research agendas, and patterns of gender differentiation. This paper focuses on self-citation in archaeology and systematically analyzes the factors that affect rates of self-citation. Self-citation rates in archaeology are significantly higher than in socio-cultural anthropology but are average for a social science with interdisciplinary ties to the physical sciences. Self-citation correlates weakly with the gender of the citing author and the geographic and thematic focus of research, but correlates strongly with the age of the author. Additional analyses reveal partial evidence for the use of self-citation as a prestige tactic. The paper concludes with a discussion of citations to writers close to the author (mentors, friends).
THE EFFECT OF ULTRAVIOLET LIGHT ON THE SODIUM AND POTASSIUM COMPOSITION OF RESTING YEAST CELLS

The Na+ and K+ content of non-metabolizing yeast cells was determined before and after monochromatic ultraviolet (UV) irradiation. UV facilitated the uptake of Na+ into and the loss of K+ from the cells (net ion flux); the effect is greatest for the shortest wavelength employed (239 mµ) and is partly dependent upon the presence of oxygen. The UV effect on net ion flux persists for at least 90 minutes during which tests were made and it occurs following dosages which are without measurable effect on colony formation. The UV effect on net ion flux is decreased by acidity and promoted by alkalinity. Addition of calcium ions in sufficient amount prevents the usual net ion flux changes observed in irradiated yeast. Increase in concentration gradient between the inside and the outside of the cell increases the net ion flux of irradiated yeast, Na+ uptake leading K+ loss in all cases. UV appears to act by disorganizing the constituents of the cell surface, permitting K+ to leave the cell in exchange for Na+. At low intensities of UV this ionic exchange approaches equivalence, but at higher intensities more Na+ is taken up than K+ is lost. Some evidence suggests that the Na+ in excess over that exchanged for K+ is adsorbed to charged groups produced by the photochemical effect of UV on the cell surface.
Ninhydrin: a color test for the differentiation of phenethylamines of abuse.

Ninhydrin is observed to differentiate among common phenethylamines of abuse. Amphetamine, methamphetamine, mescaline and STP may be easily distinguished. Colors given by phenethylamines are presented with their corresponding Munsell and ISCC–NBS values.
System of Levels in Even-Even Nuclei

The existence of a system of levels in even-even nuclei whose energies are related by an empirically determined law which seems to be applicable throughout the nuclear chart is investigated. Experimental energy ratios with their errors are tubulated for 29 elements. (A.C.)
Monte Carlo Simulation of a Solvated Ionic Polymer with Cluster Morphology

A multiscale modeling approach for the prediction of material stiffness of the ionic polymer Nafion is presented. Traditional rotational isomeric state theory is applied in combination with a Monte Carlo methodology to develop a simulation model of the conformation of Nafion polymer chains on a nanoscopic level from which a large number of end-to-end chain lengths are generated. The probability density function of end-to-end distances is then estimated and used as an input parameter to enhance existing energetics-based macroscale models of ionic polymer behavior. Several methods for estimating the probability density function are compared, including estimation using Johnson distributions, Bezier distributions, and cubic splines.
Preclinical and phase I trials of topoisomerase I inhibitors

A total of three topoisomerase I inhibitors, including topotecan, CPT-11 (irinotecan), and intoplicine, have been studied in both preclinical and clinical/clinical pharmacology studies. In in vitro testing against human tumor colony-forming units, all three compounds were significantly more effective when tested as a continuous exposure as compared with a 1-h exposure. The dose-limiting toxicities were different for all three of the agents, with neutropenia and thrombocytopenia being dose-limiting for topotecan; diarrhea, for CPT-11; and hepatotoxicity, for intoplicine. In these phase I studies a number of marginal responses were noted with topotecan; partial and marginal responses, with CPT-11 (particularly in patients with colon cancer); and no response, with intoplicine. The detailed pharmacology of all three agents documented a very short half-life for topotecan, an intermediate half-life for CPT-11, and a prolonged half-life for intoplicine. Based on our experience to date, these compounds (particularly CPT-11) have promise as useful additions to our tremendous therapeutic armamentarium.
Forecasting combination and encompassing tests

Abstract In this paper we demonstrate that forecast encompassing tests are valuable tools in getting an insight into why competing forecasts may be combined to produce a composite forecast which is superior to the individual forecasts. We also argue that results from forecast encompassing tests are potentially useful in model specification. We illustrate this using forecasts of quarterly UK consumption expenditure data from three classes of models: ARIMA, DHSY and VAR models.
Coordination and localization in spinal motor systems

We review here experiments examining the hypothesis that vertebrate spinal motor systems produce movement through the flexible combination of a small number of units of motor output. Using a variety of preparations and techniques, these experiments provide evidence for such spinally generated units and for the localization of the networks responsible for producing them within different regions of the spinal cord. Such an organization might help to simplify the production of movement, reducing the degrees of freedom that need to be specified by providing a set of units involved in regulating features common to a range of behaviors.
SINGLE STEP PURIFICATION OF BIOLOGICALLY ACTIVE RECOMBINANT RAT BASIC FIBROBLAST GROWTH FACTOR BY IMMOBILIZED METAL AFFINITY CHROMATOGRAPHY

Abstract The construction and use of a plasmid which allows the expression and single step purification of recombinant rat basic fibroblast growth factor (bFGF) is described. A cDNA encoding rat bFGF was subcloned into the expression plasmid pQE-9 (Qiagen) in such a way that the bFGF which is produced from the resulting construct contains 6 histidine residues near the amino terminus. The resulting plasmid, pQE-9-bFGF, was expressed in the E. coli strain M15[pREP4] and the 6 × His-bFGF was purified to homogeneity from the soluble fraction of the bacterial cell lysate in a single step by affinity chromatography on a nickel chelate resin. About 5 mg of 6 × His-bFGF was obtained from the soluble fraction from one liter of bacterial cell culture. Testing of the 6 × His-bFGF in a PC12 cell differentiation assay showed that its activity was comparable to the activities for native bFGF and recombinant bFGF purified by multistep methods.
Soil fertility alters the nature of plant–resource interactions in invaded grassland communities

Resource competition theory suggests that the nature of diversity–resource–invasibility interactions will vary along fertility gradients, concurrent with changes in the relative availability of limiting above- versus below-ground resources. Experimental support for this contingency is lacking. Here, we manipulated resident diversity, baseline fertility, and the availabilities of light and soil nitrogen in grassland communities invaded by two functionally distinct non-native plant species (Lolium arundinaceum and Melilotus alba). We tested the hypotheses that increased resident diversity reduces community invasibility and dampens the effects of light and soil nitrogen pulses, and that the relative effects of light versus soil nitrogen additions on diversity–invasibility relationships depend on the baseline fertility of the study system. Our results reveal an overall weak negative effect of resident diversity on Lolium performance, but in contrast to our expectations, this diversity effect did not vary with light or soil nitrogen additions or with baseline fertility. However, the relative effects of above- versus below-ground resource additions on invader performance varied with baseline fertility as expected: Lolium responded most strongly to soil nitrogen additions in low-fertility mesocosms and most strongly to increased light availability in high-fertility mesocosms. In contrast to Lolium, nitrogen-fixing Melilotus was overall less responsive to diversity and resource manipulations. Together, these patterns do not lend support for the dependence of diversity–resource–invasibility relationships on either baseline fertility or invasive species identity, but they do highlight the dominant role of resources over diversity in determining invader performance, as well as the manner in which fertility alters the relative importance of above- versus below-ground resource pulses in promoting invasions.
An Update on Psychopharmacologic Medication What Teachers, Clinicians, and Parents Need to Know

Four major classes of medications are commonly used to treat children with learning or behavioral disorders: stimulant medications, antidepressants or mood stabilizers, antipsychotics, and anticonvulsants. In addition, anxiolytics (e.g., Valium) and adrenergic agents (e.g., clonidine) are occasionally used to treat some disorders. Research estimates suggest that between 2% and 3% of all school children may be on one of these medications at any time. It has been further estimated that between 15% and 20% of children in special education may be receiving one or more of these drugs. This article discusses the potential uses and abuses of psychopharmacologic therapy with children or adolescents displaying learning, emotional, or behavioral disorders. It explores the indications and contraindications of such therapy and enumerates the known side effects of the most frequently prescribed medications.
An impression procedure for construction of maxillary immediate dentures

Abstract An impression procedure has been presented for making a master cast for an immediate denture. This impression procedure has the following advantages over the conventional impression procedures for immediate dentures: (1) improved esthetics, (2) improved comfort to the patient, (3) fewer adjustments, and (4) less servicing over a longer period of time. This technique will provide a master cast which has the same border accuracy that can be achieved in an impression of an edentulous mouth.
Diagrammatic approach to the pairing instability in an interacting Fermi gas

The pairing instability induced by either a given attractive interaction or particle-hole excitations is examined by using the perturbational diagram approach. A graphical functional derivative method based on Ward's identity is developed to represent the contributions to the interparticle interactions from different channels. It is shown that pairing instability for the electrons excited from the Fermi sea may happen due to the presence of holes even when the original interaction is repulsive. Thus, in contrast to the Cooper instability caused by a given attractive interaction, the pairing instability can be induced by the particle-hole excitations. The scattering diagrams from this model allows one to evaluate the two particle vertex function and Tc by using the pole condition of the vertex function. It has been found that Tc can reach quite high values and gives rise to the bell shape. The application of the results to a layered 2D Fermi gas is considered.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Dissertation abstract: Essays on pricing in experimental duopoly markets

This dissertation comprises three independent essays that analyze pricing behavior in experimental duopoly markets. The first essay examines whether the content of buyer information and the timing of its dissemination affects seller market power. We construct laboratory markets with differentiated goods and costly buyer search in which sellers simultaneously post prices. The experiment varies the information on price or product characteristics that buyers learn under different timing assumptions (pre- and post-search), generating four information treatments. Theory predicts that price information lowers the equilibrium price, but information about product characteristics increases the equilibrium price. That is, contrary to simple intuition, presence of informed buyers may impart a negative externality on other uninformed buyers. The data support the model's negative externality result when sellers face a large number of robot buyers that are programmed to search optimally. Observed prices conform to the model's comparative statics and are broadly consistent with predicted levels. With human buyers, however, excessive search instigates increased price competition and sellers post prices that are significantly lower than predicted. The second essay uses experimental methods to demonstrate the anti-competitive potential of price-matching guarantees in both symmetric and asymmetric cost duopolies. When costs are symmetric, price-matching guarantees increase the posted prices to the collusive level. With asymmetric costs, guaranteed prices remain high relative to prices without the use of guarantees, but the overall ability of guarantees to act as a collusion facilitating device depends on the relative cost difference. Fewer guarantees, combined with lower average prices, suggest that cost asymmetries may discourage collusion. The third essay investigates the effect of firm size asymmetry on the emergence of price leadership in a homogeneous good duopoly. With discounting, the unique subgame-perfect equilibrium predicts that the large firm will emerge as the endogenous price leader. Independent of the level of size asymmetry, the laboratory data indicates that price leadership by the large firm is one of the most frequently observed timings of price announcement. In most cases, however, it comes second to simultaneous price-setting. This tendency to wait for the other firm to announce its price is especially strong when the level of size asymmetry between firms is low. We attribute the lower than expected frequency of price leadership to coordination failure, which is further compounded by elements of inequity aversion.
Microelectrode study of Wenckebach periodicity in canine Purkinje fibers

Abstract Electrophysiologic mechanisms responsible for Wenckebach periodicity produced experimentally in a segment of blocked canine Purkinje fibers were investigated with multiple microelectrode recordings. Transmission through the zone of block was electrotonic. The Wenckebach mechanism was related to a progressive decrease in the efficacy of the transmitted electrotonic potential as a stimulus for the regenerative response at the distal block boundary with successive impulses of the cycle. This was manifested in the transmembrane potentials as a progressive decrease in upstroke velocity and a voltage change that caused the electrotonic potential to become progressively removed from the threshold for stimulation. The immediate cause of this phenomenon was a progressive increase in the voltage level (more negative) from which the electrotonic potential originated and a resulting change in voltage-dependent membrane resistance that further attenuated the signal with successive impulses of the cycle. Two main mechanisms appeared to be responsible for these phenomena: (1) a progressive increase in maximal repolarization voltage (more negative) of the transmembrane potential, and (2) a progressive decrease in the diastolic interval that, in the presence of enhanced phase 4 diastolic depolarization, caused the voltage level from which the electrotonic potential originated to become further removed from the stimulation threshold with successive impulses of the cycle.
Structure determination of three furan-substituted benzimidazoles and calculation of π-π and C-H···π interaction energies.

The synthesis and structural characterization of 2-(furan-2-yl)-1-(furan-2-ylmeth­yl)-1H-benzimidazole [C16H12N2O2, (I)], 2-(furan-2-yl)-1-(furan-2-ylmeth­yl)-1H-benzimidazol-3-ium chloride monohydrate [C16H13N2O2+·Cl−·H2O, (II)] and the hydro­bromide salt 5,6-dimethyl-2-(furan-2-yl)-1-(furan-2-ylmeth­yl)-1H-benzimidazol-3-ium bromide [C18H17N2O2+·Br−, (III)] are described. Benzimidazole (I) displays two sets of aromatic inter­actions, each of which involves pairs of mol­ecules in a head-to-tail arrangement. The first, denoted set (Ia), exhibits both inter­molecular C—H⋯π inter­actions between the 2-(furan-2-yl) (abbreviated as Fn) and 1-(furan-2-ylmeth­yl) (abbreviated as MeFn) substituents, and π–π inter­actions involving the Fn substituents between inversion-center-related mol­ecules. The second, denoted set (Ib), involves π–π inter­actions involving both the benzene ring (Bz) and the imidazole ring (Im) of benzimidazole. Hydrated salt (II) exhibits N—H⋯OH2⋯Cl hydrogen bonding that results in chains of mol­ecules parallel to the a axis. There is also a head-to-head aromatic stacking of the protonated benzimidazole cations in which the Bz and Im rings of one mol­ecule inter­act with the Im and Fn rings of adjacent mol­ecules in the chain. Salt (III) displays N—H⋯Br hydrogen bonding and π–π inter­actions involving inversion-center-related benzimidazole rings in a head-to-tail arrangement. In all of the π–π inter­actions observed, the inter­acting moieties are shifted with respect to each other along the major mol­ecular axis. Basis set superposition energy-corrected (counterpoise method) inter­action energies were calculated for each inter­action [DFT, M06-2X/6-31+G(d)] employing atomic coordinates obtained in the crystallographic analyses for heavy atoms and optimized H-atom coordinates. The calculated inter­action energies are −43.0, −39.8, −48.5, and −55.0 kJ mol−1 for (Ia), (Ib), (II), and (III), respectively. For (Ia), the analysis was used to partition the inter­action energies into the C—H⋯π and π–π components, which are 9.4 and 24.1 kJ mol−1, respectively. Energy-minimized structures were used to determine the optimal inter­planar spacing, the slip distance along the major mol­ecular axis, and the slip distance along the minor mol­ecular axis for 2-(furan-2-yl)-1H-benz­imidazole.
Immunohistochemical detection of mutant P53 protein and human papillomavirus-related E6 protein in anal cancers

PURPOSE: The wild-type P53 protein, a product of theP53gene, is a normal growth controlling protein. Mutation of theP53gene generates a mutant P53 protein which promotes tumor formation through loss of growth suppression. Some of the agents responsible forP53gene mutation are known, one of which may be tumorigenic human papillomavirus (HPV) infection. Anal cancers are demonstrating a changing trend in the affected population, from older females in the older reported series to younger males more recently. This may be a reflection of infection with tumorigenic HPV types 16 and 18. The E6 oncoprotein of these viruses inactivates the growth-controlling wild-type P53 protein. In this study, our purpose was to determine the incidence of mutant P53 and HPV-16 and 18-related E6 protein and their coexpression in anal cancers. METHODS: We examined 29 anal cancers immunohistochemically for mutant P53 protein, HPV 16 and 18 E6 protein, and coexpression of the two. RESULTS: Mutant P53 protein was present in 58.6 percent of anal cancers overall and in 85.7 percent of anal adenocarcinomas. E6 oncoprotein was present in five cases (17.2 percent), all of which were squamous-cell carcinomas. Coexpression of both mutant P53 and E6 proteins was seen in only three cases (10.3 percent). CONCLUSION: Although tumorigenic HPV may be an important cause forP53gene mutation in anal cancers, perhaps other mutagenic factors play a predominant role.
Nfkb1 suppresses DNA alkylation-induced tumor formation

NF-κB proteins play a complex role in modulating carcinogenesis following DNA damage. Previous work identified p50/NF-κB1 as a necessary factor in the cytotoxic response to alkylation damage. Recently, these findings were extended to demonstrate that in the setting of alkylation damage, this NF-κB subunit acts as a haploinsufficient tumor suppressor that prevents hematologic malignancy formation.
The safety of preoperative sedation in children with sleep-disordered breathing

Summary Objective To prospectively monitor children who received preoperative sedation with midazolam hydrochloride prior to adenotonsillectomy (T&A) for treatment of sleep-disordered breathing with continuous pulse-oximetry to detect potential respiratory compromise. Design Prospective, observational study. Setting Hospital-based pediatric otolaryngology practice. Patients Seventy children, aged 1–12 years, diagnosed with sleep-disordered breathing by clinical evaluation or polysomnography (PSG), with a median RDI of 14.25, undergoing T&A. Methods Children underwent a standardized anesthesia protocol including preoperative oral midazolam hydrochloride 0.5 mg/kg, standard American Society of Anesthesiologists (ASA) monitoring, mask induction with sevoflurane, muscle relaxant with reversal if indicated, and intravenous dexamethasone sodium phosphate 0.5 mg/kg. Children were monitored in the hospital until discharge criteria were met. Selected children with severe OSA were monitored overnight on the pediatric floor or the pediatric intensive care unit. Adverse respiratory events were defined as upper airway obstruction, hypoventilation, desaturation, bradycardia, or sustained lethargy. Main outcome measures Incidence of pre and postoperative obstructive complications. Results During the study period only two patients (2.9%) had a measurable adverse event directly related to the administration of the sedation. Conclusion Based on sporadic reports of adverse airway events in children with obstructive sleep apnea receiving sedation, these children frequently do not receive preoperative sedation. Given the low morbidity of preoperative sedation in our population, many children with sleep-disordered breathing may safely be pre-medicated.
NMR study of interaction between several penicillins and nucleosides

Abstract Nuclear magnetic resonance studies are reported on the interaction between three penicillins (penicillin-G, carbenicillin, and hydrabamine penicillin-G) and five nucleosides (guanosine, adenosine, uridine, thymidine, and cytidine) in dimethyl sulfoxide. Penicillin-G interacts with guanosine, and can break the strong guanosinecytidine pairing by forming a binary hydrogen-bonded complex of penicillin-G-guanosine. The binding sites in penicillin-G are the carboxylate group and the adjacent carbonyl groups, while the NH and NH 2 groups of guanosine act as hydrogen donors. The interaction of penicillin-G with cytidine or adenosine is significantly weaker than with guanosine. With uridine and thymidine, the carboxylate group appears to be the only binding site in penicillin-G, with the NH group in uridine and thymidine as the hydrogen donor. Carbenicillin interacts less strongly with guanosine and adenosine than does penicillin-G, and does not interact with cytidine, uridine, or thymidine. There is no evidence of interaction between hydrabamine penicillin-G and any of the five nucleosides studied.
MALDI-TOF Mass Spectrometry in the Clinical Microbiology Laboratory

Abstract Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) has been adapted to generate protein mass spectra from whole bacteria and other microorganisms. These spectra can be compared to a reference database for rapid and accurate taxonomic classification of unknown organisms at the genus, species, and, in some instances, strain levels. The recent development of integrated commercial MALDI-TOF MS instruments has made this technology available for use in European diagnostic clinical microbiology laboratories, where it has been employed successfully to identify organisms from colonies, as well as from cultured blood and primary urine specimens. This article reviews the principles of MADLI-TOF MS and the recent literature evaluating its performance in the clinical laboratory.
Effects of mean luminance on goldfish temporal contrast sensitivity

The goldfish is an important animal model for retinal processing and for understanding the relationship between retinal structure and function. The purpose of this study was to examine the temporal processing of the visual system of this species. Goldfish were classically conditioned to suppress respiration upon presentation of a sinusoidally flickering stimulus. Temporal contrast sensitivity functions (T-CSFs) were determined by measuring contrast threshold at a variety of temporal frequencies across different mean luminances. Goldfish T-CSFs were found to be similar in shape to those of humans. In addition, as the mean luminance of the stimulus decreased, temporal resolution decreased. This implies that the animal's ability to detect high flicker frequencies decreases as the level of light adaptation decreases, as does that of humans. The results support the notion that temporal processing is similar across vertebrate species, and therefore that the goldfish is a useful model for studying temporal processing in the vertebrate retina.
The Synaptic Localization of NR2B-Containing NMDA Receptors Is Controlled by Interactions with PDZ Proteins and AP-2

Summary The NMDA receptor (NMDAR) is a component of excitatory synapses and a key participant in synaptic plasticity. We investigated the role of two domains in the C terminus of the NR2B subunit—the PDZ binding domain and the clathrin adaptor protein (AP-2) binding motif—in the synaptic localization of NMDA receptors. NR2B subunits lacking functional PDZ binding are excluded from the synapse. Mutations in the AP-2 binding motif, YEKL, significantly increase the number of synaptic receptors and allow the synaptic localization of NR2B subunits lacking PDZ binding. Peptides corresponding to YEKL increase the synaptic response within minutes. In contrast, the NR2A subunit localizes to the synapse in the absence of PDZ binding and is not altered by mutations in its motif corresponding to YEKL of NR2B. This study identifies a dynamic regulation of synaptic NR2B-containing NMDARs through PDZ protein-mediated stabilization and AP-2-mediated internalization that is modulated by phosphorylation by Fyn kinase.
Consequences of Considering Carbon–Nitrogen Interactions on the Feedbacks between Climate and the Terrestrial Carbon Cycle

Abstract The impact of carbon–nitrogen dynamics in terrestrial ecosystems on the interaction between the carbon cycle and climate is studied using an earth system model of intermediate complexity, the MIT Integrated Global Systems Model (IGSM). Numerical simulations were carried out with two versions of the IGSM’s Terrestrial Ecosystems Model, one with and one without carbon–nitrogen dynamics. Simulations show that consideration of carbon–nitrogen interactions not only limits the effect of CO2 fertilization but also changes the sign of the feedback between the climate and terrestrial carbon cycle. In the absence of carbon–nitrogen interactions, surface warming significantly reduces carbon sequestration in both vegetation and soil by increasing respiration and decomposition (a positive feedback). If plant carbon uptake, however, is assumed to be nitrogen limited, an increase in decomposition leads to an increase in nitrogen availability stimulating plant growth. The resulting increase in carbon uptake by v...
Mechanism of template-label matching in fire ant, Solenopsis invicta Buren, nestmate recognition

Abstract Aggression bioassays were used to investigate how fire ant workers ‘match’ perceived odour labels of encountered individuals with a learned template of nestmate odours. A split-colony design was used, with parent colonies and subcolonies receiving different diets. Diets either shared all components, shared some components but contained no unshared components, or contained both shared and unshared components. Results suggest that workers ‘compared their colony odour template with labels of encountered kin by ‘overall similarity’ rather than by a ‘discrete odour’ mechanism requiring either (1) exact cue correspondence between templates and labels, (2) rejection of an individual whose label contains any cue not present in the template (foreign label rejection), or (3) acceptance of an individual whose label contains any cue present in the template (habituated label acceptance).
Strain and sex variations in the sensitivity of mice to dominant-lethal induction with ethyl methanesulfonate

Abstract Male and female mice from two hybrid strains and a random-bred one were subjected to dominant-lethal induction with ethyl methanesulfonate. In female mice, 1 strain revealed a strong mutagenic action of ethyl methanesulfonate while the other 2 strains did not. In male mice, all 3 strains exhibited high sensitivity to the mutagenic action of ethyl methanesulfonate with only minor strain differences. The results thus revealed the existence of large sex differences in 2 of the 3 strains and large strain differences in the response of females.