cssi/SciSciGPT-SciSciNet huggingface dataset:
Synergistic effect of local endothelial shear stress and systemic hypercholesterolemia on coronary atherosclerotic plaque progression and composition in pigs.

Background Systemic risk factors and local hemodynamic factors both contribute to coronary atherosclerosis, but their possibly synergistic inter-relationship remains unknown. The purpose of this natural history study was to investigate the combined in-vivo effect of varying levels of systemic hypercholesterolemia and local endothelial shear stress (ESS) on subsequent plaque progression and histological composition.
Monte Carlo Simulation of Interlamellar Isotactic Polypropylene

Monte Carlo molecular simulations are reported to investigate the amorphous region between crystalline lamellae of isotactic polypropylene ( iPP). It is the first such study in which consideration is given to the nature of pendant side groups on the polymer chain. The crystalline lamellae are modeled after the R2 crystal of iPP, while the interphase and amorphous domains are equilibrated with respect to both spatial and topological degrees of freedom. A united atom force field is used to describe the interactions between the methyl, methylene, and methyne moieties that constitute a polypropylene molecule. Mass density and bond orientational order profiles, distributions of chain populations, interphase thicknesses, interfacial energies, local conformations as characterized by torsional angle sequences, and chain reentry statistics are studied for three different temperatures. Our results match well with the available experimental data and provide a molecular level understanding of the semicrystalline interphase for isotactic polypropylene. A comparison with linear polyethylene (PE) reveals the effects of chemical architecture on the crystal -amorphous interphase in semicrystalline polymers. Semicrystalline polymers have found widespread use due to their excellent mechanical and barrier properties. The crystal- lization of polymers corresponds to a first-order phase transi- tion, 1 similar to other substances. However, a significant difference between long chain molecules and their low molecular weight counterparts lies in the kinetics of the crystallization process, because of which the complete incorporation of polymer molecules into the ordered crystalline state is rarely achieved. Thus, "semicrystalline" polymers are structurally nonhomoge- neous materials and invariably consist of an intimate mixture of crystalline and amorphous phases. These polymers exhibit properties that are a consequence of the combined attributes of ordered (crystalline) and disordered (amorphous) constituent regions, with the unique feature that both crystalline and noncrystalline elements are topologically connected by chains that meander their way from region to region. A comprehensive understanding of the behavior of semicrystalline polymers thus demands extensive knowledge not only of the individual phases but also the interplay between them. The existence and lamellar nature of semicrystalline polymers have been known for approximately half a century. 2-8 Various facets that describe the state of the semicrystalline system can be identified, including the gross morphological structure, degree
Actions of neuropeptide Y on basal, cyclic AMP-induced and neurally evoked ion transport in porcine distal jejunum

Abstract Neuropeptide Y (NPY) and its homolog, peptide YY, are present respectively in neurons and endocrine cells within the mammalian small intestine. In this study, we examined the actions of NPY on ion transport in the porcine distal jejunum mucosasubmucosa in vitro. Peptide YY and NPY were equieffective in producing rapid and sustained decreases in basal short-circuit current ( I sc ), a bioelectrical measure of active ion transport, eliciting half-maximal decreases at respective serosal concentrations of 0.8 and 30 nmol/l. NPY-induced changes in I sc were due to increased mucosa-to-serosa and net Cl fluxes and were not affected by the absence of extracellular HCO 3 ions. NPY activity was correlated with the magnitude of the basal I sc and appeared to depend on the spontaneous production of eicosanoids. The peptide also decreased I sc stimulated by forskolin and 8-bromo-cyclic AMP, but the ionic bases for this effect were complex and differed from those determined under basal conditions. NPY attenuated increases in I sc produced by electrical stimulation of enteric neurons with an IC 50 = 5 nmol/l. The actions of the peptide on basal and cyclic AMP-induced ion transport were abolished by the neuronal conduction blocker tetrodotoxin, but not by the opiate antagonist naloxone. The α-adrenoceptor blocker phentolamine diminished the effects of NPY on basal, but not cyclic AMP-induced I sc . These results indicate that NPY is capable of modulating NaCl transport in the porcine jejunal mucosa under several different conditions. Furthermore, the effects of the peptide are mediated in part through noradrenergic nerves as well as enteric neurons of unknown chemical identity.
Melting of a solid in porous medium induced by free convection of a warm dissimilar fluid

Buoyancy-driven flow from a vertical flat plate in porous medium was investigated first by Cheng and Minkowycz. Their results were extended later to the case of cold water natural convection by Ramilison and Gebhart. In two recent studies Epstein and Cho and Kazmierczak et al. studied theoretically the effect of forced and natural convection, respectively, on the phenomenon of melting from a flat plate embedded in porous medium. The present study pertains to a different class of melting problems in porous medium. Unlike the above studies where both the solid and the liquid phase are of the same substance, here melting from a vertical flat plate is initiated by a warm fluid that is dissimilar to the solid phase it surrounds. Therefore, the liquid in the melt layer is dissimilar to the warm liquid outside the melt layer. Of particular interest to the present study is the case where the density difference between the melt and the ambient fluid is considerably greater than that caused by thermal expansion. Hence, the buoyancy force responsible for the motion in the melt layer originates from differences in material densities and not, as is customarily assumed, from temperature differences. Regarding the warm ambient fluidmore » responsible for the initiation and continuation of the melting phenomenon, it is assumed that the temperature gradients existing in the vicinity of the interface between the ambient fluid and the melt region drive a natural convection flow inside the ambient fluid near the melt/ambient fluid interface. This flow is taken into account and its effect on the melting phenomenon is thoroughly investigated. The main application of the basic research reported in this paper is in geophysical heat transfer where melting of the type studied here may occur, resulting in the spreading of pollutants.« less
Identification and cloning of the G3B cDNA encoding a 3' segment of a protein binding to GATA-3.

Abstract The transcription factor GATA-3 contributes to the expression of several genes critical for T-cell function and development, including the T-cell receptor α and β chains. We report here the isolation of a human cDNA clone which encodes a 3′ segment of a novel protein with three zinc fingers. This protein, which we termed G3B, can interact with GATA-3 in vitro. Its mRNA is expressed in T and B cells. Thus, G3B may represent a potential regulator of GATA-3 function.
NEW STANDARD FOR SUCCESS OF THROMBOLYTIC THERAPY : AN EARNEST PROPOSAL

Some years ago, the late Lewis Thomas made “an earnest proposal”1 : that the world powers agree to restrain computers from launching nuclear warheads until we acquire a really complete set of information describing at least one living creature. “When this is done,” he wrote, “and the information programmed into all our computers, I for one would be willing to take my chances.” As the subject for this investigation, he proposes the simple protozoan, Myxotricha paradoxa , a fast-swimming inhabitant of the intestine of the Australian termite. But it turns out that the myxotricha is not as simple as it appears. Under the scrutiny of the electron microscope, its flagella, which beat in synchrony to propel it through its watery world, are perfectly spaced, fully formed spirochetes. Myxotricha’s oval cytoplasmic organelles, engorged with undigested wood, are bacteria contributing enzymes to break down cellulose, and its centrioles are a third set of separate creatures. At the end of a decade of collecting information, Thomas envisions the moment when science’s remarkable discoveries about myxotricha are fed into the computers. After a few seconds of whirring, there comes a neat and speedily printed message: “Request more data. How are spirochetes attached? Do not fire!” So it seems to be with treatment of acute thrombotic occlusion of blood vessels: there is never quite enough information. In this issue of Circulation , Vanderschueren et al2 describe recanalization of thrombosed peripheral arteries with staphylokinase, called STAR, a proteolytic enzyme produced by certain strains of Staphylococcus aureus . The substance itself is hardly a new discovery; its fibrinolytic properties were clearly described a half century ago.3 Nevertheless, in several experimental animal models, STAR appears to be as potent as streptokinase for dissolution of whole blood clots and significantly more potent for lysing platelet-rich thrombi. …
Tomography of the mind.

The machine whirs and clicks from slice to slice, as thetechnician watches through a shielded window and theimmobile patient moves on a pallet through a series ofstations. The mass of data from this exercise goes to afast computer and is integrated into detailed cross sec-tions in three dimensions. Equally, the data could beused to construct a three-dimensional model in space.The marvels of the CAT, MRI, SPECT scans and theirenhancements never fail to astonish us.Minus the whirring and clicking, a comparable eventtakes place minute-to-minute in the mind of the skilledpsychotherapist. In my long career, this process and thetherapy it enables have been the most fascinating andrewarding part of being a psychiatrist.What emerges onthe computer screen of my mind is not just three but aplethora of dimensions of my patient’s—and my own—mental operations. Most of them were originally definedby Sigmund Freud and a succession of brilliant psycho-analysts who built on his work. Some have been extend-ed by the analysts who founded other forms ofpsychotherapy, usually coning down on one dimensionor another. Together they provide an array of possibili-ties for understanding and intervening with the patientand the illness.While the interpreters of diagnostic imaging have tolook at one slice at a time, the skilled psychotherapistmay be assessing multiple dimensions simultaneously.Nor are therapists limited to the four dimensions ofspace and time. The concept of multiple perspectiveswas originally formulated by Rapaport, Hartmann, andothers
Mitotic inhibition and nucleic acid synthesis in amoeba nuclei.

SEVERAL strains of large mononucleate amoebae contain specific proteins which inhibit mitosis and eventually kill amoebae of strains other than their own1,2. We now describe experiments to show that this lethal antimitotic factor (AF) inhibits RNA synthesis when injected into susceptible cells.
Toughness of Flake-Reinforced Polypropylene

This paper discusses the mechanisms governing the fracture toughness of polypropylene reinforced by either mica or glass flakes. The toughness of these compos ites is found to be controlled by the competition between shear yielding and voiding in the matrix. Shear yielding occurs around filler particles, because of debonding at the filler/matrix interface. The filler onentation does not affect the crack growth resistance, but there is a unique relationship between the latter and the average distance between par ticles, regardless of the nature of the filler. It has also been found that the glass-rubber relaxation of the matrix polypropylene is the governing parameter for the time dependence of the dynamic fracture toughness of these composites.
Cooperative Compressive Spectrum Sensing in Cognitive Radio Based on W-OMP

Spectrum Sensing is an intensively studied topic in cognitive radio to locate unoccupied spectrum for improved channel utilization. However, the problem becomes more challenging in wideband spectrum sensing due to the limitation of hardware operational bandwidth. In this paper, we introduce a cooperative compressive spectrum sensing scheme to monitor the wideband spectrum usage in both frequency and space domain. The joint estimation enables secondary users (SUs) to identify (un)used frequency bands at arbitrary locations, and thus facilitates spatial frequency reuse. A novel weighted-Orthogonal Matching Pursuit (W-OMP) spectrum reconstruction algorithm based on OMP is developed to mitigate the effect of path shadowing and is able to significantly improve the detection performance. In addition, the implementation of W-OMP can be further simplified by taking advantage of the channel information. The simulation experiments show the feasibility of the proposed scheme, and demonstrate the superior performance of this method.
Ras-independent growth factor signaling by transcription factor tyrosine phosphorylation

Interferons induce transcriptional activation through tyrosine phosphorylation of the latent, cytoplasmic transcription factor interferon-stimulated gene factor-3 (ISGF-3). Growth factors and cytokines were found to use a similar pathway: The 91-kilodalton subunit of ISGF-3 was activated and tyrosine phosphorylated in response to epidermal growth factor (EGF), platelet-derived growth factor, and colony stimulating factor-1. The tyrosine phosphorylated factor acquired DNA binding activity and accumulated in nuclei. Activation required the major sites for autophosphorylation on the EGF receptor that bind Src homology region 2 domain-containing proteins implicated in Ras activation. However, activation of this factor was independent of the normal functioning of Ras.
A partition technique for the solution of potential flow problems by integral equation methods

Abstract Discretization of integral equation methods for the computation of potential flows results in dense matrices. The partition technique of this paper is designed to remove this restriction on the size of problems that can be efficiently computed by integral equation methods. This technique consists of dividing the domain by partition curves and then applying a standard integral equation method to each of the subdomains. The potential on the partition curves as well as the absolute value of its normal derivative are considered to be additional unknowns. Although the number of unknowns was thus increased, the number of nonzero entries in the matrix of the extended system was considerably reduced. Using a partial elimination process in each of the subdomains, a determined system of equations for the unknowns on the partition curves is automatically derived. Once the latter is solved, the solution in each of the subdomains is obtained by back substitution. The partition technique extends to problems in an unbounded domain with a radiation condition, and can be easily implemented in existing computer programs. To describe the technique, we choose the particular problem of time harmonic motion of floating bodies in two dimensions.
Computer aided enzyme design and catalytic concepts

Gaining a deeper understanding of enzyme catalysis is of great practical and fundamental importance. Over the years it has become clear that despite advances made in experimental mutational studies, a quantitative understanding of enzyme catalysis will not be possible without the use of computer modeling approaches. While we believe that electrostatic preorganization is by far the most important catalytic factor, convincing the wider scientific community of this may require the demonstration of effective rational enzyme design. Here we make the point that the main current advances in enzyme design are basically advances in directed evolution and that computer aided enzyme design must involve approaches that can reproduce catalysis in well-defined test cases. Such an approach is provided by the empirical valence bond method.
Co–salen complexes as catalysts for the asymmetric Henry reaction – reversed enantioselectivity through simple ligand modification

The asymmetric Henry reaction is an efficient method for the synthesis of enantioenriched nitro alcohols. We investigated the catalytic activity and enantioselectivity of derivatives of Co–salen [salen = N,N′-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexane-diamine] in this reaction. Tetrahydro-salen (salan) complexes displayed a reversed enantioselectivity compared to their Schiff-base counterparts. Oligomeric Co–salen catalysts showed a higher activity than their small molecule analogues, indicating a bimetallic pathway.
Extending the participatory learning paradigm to include source credibility

We provide an overview of the participatory learning paradigm (PLP) and discuss the importance of the acceptance function in determining which observations are used for learning. We introduce a formal model that uses this (PLP) We then extend this model in two directions. First, we consider situations in which we have incomplete observations, we only have observations about a subset of the variables of interest. Next we extend this model to allow for the inclusion in the learning process of information about the learning agents belief about the credibility of the source of the learning experience. Here we distinguish between the content of a learning experience and the source of the experience. We provide a means to allow the learning agents belief about the credibility of the source to determine the effect of the content. Furthermore we suggest a method to allow the modification of agents belief about the credibility of the source to also be part of the learning process.
Respiratory afferent activity in the superior laryngeal nerves

This study evaluates the afferent activity in the superior laryngeal nerve (SLN) during breathing as well as during occluded inspiratory efforts. Experiments were performed in 11 anesthetized and spontaneously breathing dogs. Electroneurographic activity was recorded from the peripheral cut end of the SLN and, in 3 dogs, also from the contralateral vagus nerve. A tracheal cannula with a side arm allowed the bypass of the larynx during breathing and occluded efforts. A clear inspiratory modulation was present in all experimental conditions. Both peak and duration of the SLN activity decreased (87% and 89%) when breathing was diverted from the upper airway to the tracheostomy. Peak and duration of the SLN activity (as % of upper airway breathing) increased during occluded efforts; however, the increase was greater when the larynx was not by-passed (peak = 118% vs 208%, duration = 143% vs 178%). Section of the ipsilateral recurrent laryngeal nerve reduced the inspiratory modulation. Vagal afferent activity increased equally during tracheostomy and upper airway breathing and decreased markedly during tracheal and upper airway occlusions. Our results indicate that collapsing pressure in the larynx is the major stimulus in activating laryngeal afferents.
Chemical reactions in perfume ageing.

Summary The interactions between a typical range of perfume materials, alcohol, water, air, elevated temperatures and daylight have been studied. The changes of composition, acidity, peroxide content and the formation of new molecules were followed. The stabilizing effects of UV absorbers, antioxidants and sequestering agents were examined; - the formation of acid reaction products was accelerated by air, temperature, daylight and the presence of natural products; - peroxide formation was accelerated by heat and light and the presence of air; as the acidity increased, the peroxides decomposed; - the acetalization of other aldehydes was accelerated by temperature and daylight and the presence of natural products up to 40% of certain aldehydes may be converted into acetals after 3 months at 37 degrees C; - many stereoisomerizations occur, e.g., transisoeugenol is converted up to 10% into the cis isomer after 3 months at 37 degrees C and 58% in daylight; - evaluation of antioxidants UV absorbers and sequestering agents showed a significant protection against deterioration only by EDTA dipotassium salt; - ethanol was converted into acetaldehyde and its diethylacetal by peroxides present and formed on ageing up to 0.08%. Natural products accelerated this formation; - the reaction between benzoyl peroxide and ethanol was shown to yield up to 63% of acetaldehyde+diethyl acetal whilst di-t-butyl peroxide gave only 23% under the same conditions. These results go some way to explaining odour changes in perfume ageing.
Development of a Framework for Predicting Incident Probabilities of All Terrain Vehicle Use Across a Semi-Arid Landscape

Recreational All-Terrain Vehicle (ATV) activities can fulfill people’s needs in physical, mental, and spiritual well-being, as well as provide significant economic contributions to local jurisdictions. Nevertheless, ATV use creates multiple environmental issues ranging from air and water pollution to soil erosion. Accurately forecasting the incidence locations of ATV activities helps to form the foundation for robust environmental management and conservation intervention. However, drivers’ behavioral patterns have rarely been investigated within a geospatial context to enhance forecasting ability. This paper presents a novel process for estimating occurrence probability of ATV activities in a landscape near Las Cruces, New Mexico, USA, based on a 5 m-resolution web that unifies information extracted from the applications of remote sensing and GIS technologies. The model is composed of three major aspects: object-based classification and validation for the generation of the trail inventory, parameterization, and logistic regression analysis. Rider behavioral patterns were parameterized by quantifying the relationship embedded in the interactions between riders and the terrain. The model outcomes were then analyzed to portray riding patterns in responding to landscape features. The analyses demonstrated that the involvement of riding patterns, such as tailing of ridge branches and previous disturbances, generated significant results. The application of the Area under the Receiver Operating Characteristics Curve (AUROC) validation technique results in an accuracy value greater than 0.8. Accurately foreseeing the spatial distribution of possible newly formed places for ATV activities will facilitate the inauguration of sound recreational policies, which in turn reduces ATV impacts on environments and retains welfare of non-motorized tourists.
The holistic grail: possible implications of an initial mistake in the reading of digital mammograms

In 1967 Ulric Neisser, studying how laypeople examined pictures, hypothesized that image perception occurs in two stages, a pre-attentive stage in which the entire image is processed in parallel, where a 'holistic' view of what is being displayed is formed, and a secondary stage in which items or groups of items are examined by focal attention. Later, the proponents of Neisser's theory suggested that the pre-attentive stage may bias the selection of the areas that will be subjected to further analysis. This is easily seen in those dual interpretation figures; once one 'sees' the figure in a certain way, it is very hard to instruct the eye-brain system to let go of that perception and 'see' the figure in the alternative way. In medical image perception, Harold Kundel and Calvin Nodine proposed a model of medical image interpretation that is based upon Neisser's two stages, and have become so convinced of the influence of the 'holistic' view on the subsequent reading of the image that they have recently questioned the traditional framework that determines how lesions are found. In other words, as opposed to the traditional view of SEARCH THE IMAGE - DETECT A POSSIBLE FINDING - IDENTIFY THE FINDING - DECIDE WHAT TO DO ABOUT THE IMAGE, Kundel and Nodine have recently suggested a new framework: DETECT A POSSIBLE FINDING - IDENTIFY THE FINDING - SEARCH THE IMAGE - DECIDE WHAT TO DO ABOUT THE IMAGE. In light of this significant switch, we decided to investigate what happens when the 'holistic' view is incorrect.
Protection against Lethal Damage Induced by Ultraviolet Radiation.

SUMMARY. Sodium pyruvate, glutathione, potassium cyanide, dextrose, sucrose, 3 nucleic acid derivatives, 11 B-vitamins, and 22 amino acids were tested for their ability to protect Astasia longa against the lethal damage induced by ultraviolet radiation. Compounds which protected when added to a cell suspension just before irradiation were cystine, phenylalanine, tryptophan, tyrosine, adenine, cytidylic acid, uracil, and sodium pyruvate. None of these compounds protected when added immediately after irradiation. Except for phenylalanine, solutions of these compounds afforded protection when used as filters between the ultraviolet source and the flagellates. Cysteine failed to protect when added just before irradiation, but gave good protection when cells were grown in its presence.
Reproducibility and variability of the cost functions reconstructed from experimental recordings in multifinger prehension.

ABSTRACT The study examines whether the cost functions reconstructed from experimental recordings are reproducible over time. Participants repeated the trials on three days. By following Analytical Inverse Optimization procedures, the cost functions of finger forces were reconstructed for each day. The cost functions were found to be reproducible over time: application of a cost function Ci to the data of Day j (i≠j) resulted in smaller deviations from the experimental observations than using other commonly used cost functions. Other findings are: (a) the 2nd order coefficients of the cost function showed negative linear relations with finger force magnitudes; (b) the finger forces were distributed on a 2-dimensional plane in the 4-dimensional finger force space for all subjects and all testing sessions; (c) the data agreed well with the principle of superposition, i.e. the action of object prehension can be decoupled into the control of rotational equilibrium and slipping prevention.
First principles study of the electronic and geometric structure of Cu(5 3 2)

Abstract Using density functional theory with the generalized gradient approximation and ultra-soft pseudo-potentials, we have calculated structural relaxations of the Cu(5 3 2) surface which contains steps and kinks. We find the relaxation pattern to oscillate dramatically for atoms in the first 10 layers before decaying rapidly in the bulk. The most striking feature is an outward expansion of the relative interlayer separation d 12 of 25%. We also find serious discrepancies with relaxation pattern and relaxation amplitudes calculated using embedded atom method potentials that may reflect the limitation of these potentials to accurately describe systems with complex geometries. Full potential calculations reveal a dispersionless surface state along a high symmetry direction in the surface Brillouin zone. Valence charge density along several planes show excess of charge around kink atom and the nature of bonding with other (5 3 2) atoms.
Power-law rheology in the bulk and at the interface: quasi-properties and fractional constitutive equations

United States. National Aeronautics and Space Administration (Microgravity Fluid Sciences (Code UG) for support of this research under grant no. NNX09AV99G)
General methods for the synthesis of methyl isotope labelled catecholamine metabolites. Preparation of 4‐hydroxy‐3‐methoxy‐d3‐ (mandelic acid, phenylacetic acid, and phenylethylene glycol)

Two general schemes for the synthesis of isotope labelled monomethyl catecholamine metabolites are described. Catechol was converted to 2-methoxy-d3-phenol (2) with deuteromethyl iodide and reacted with sodium glyoxylate to form 4-hydroxy-3-methoxy-d3-mandelic acid (3). Hydrogenolysis of the methyl ester-diacetate of 3 with excess sodium borohydride in water yielded 4-hydroxy-3-methoxy-d3-phenylacetic acid (4). Reduction of 3 with diborane produced 4-hydroxy-3-methoxy-d3-phenylethylene glycol (5). An alternative route was to alkylate 3,4-dihydroxybenzaldehyde (6) and produce 3 or its 3-hydroxy-4-methoxy isomer via the nitrile mandelic acid synthesis. Suitability of these isotopic and isomeric variants as internal standards for quantitation by gas chromatography-mass spectrometry is discussed.
Prophylactic Antibiotics for Severe Acute Pancreatitis: The Beginning of an Era

Death from acute severe pancreatitis results from infection and multiple organ system failure occurring late in the course of illness. Patients with necrotizing pancreatitis involving at least one-third of the organ are at highest risk of secondary infection and death. We conducted a MEDLINE search to identify human trials of prophylactic antibiotics in acute pancreatitis. Results of early studies of prophylactic ampicillin to avoid secondary infection and death were negative, but the studies included patients with mild disease who are at low risk for infection. Antibiotics were beneficial in four recently completed studies: imipenem significantly reduced pancreatic and nonpancreatic sepsis (p≤ 0.01); cefuroxime reduced all infectious complications (p< 0.01) and deaths (p= 0.0284); a regimen of ceftazidime, amikacin, and metronidazole reduced all infectious complications (p< 0.03); and protocol use of imipenem significantly reduced pancreatic infection compared with nonprotocol antibiotics (p= 0.04) and no antibiotics (p< 0.001). Based on these results, we suggest early antibiotic prophylaxis in patients with necrotizing pancreatitis, but the best drug and duration of therapy are unknown.
Switched Gain - A Technique for Simplifying Ultrasonic Measurement of Cardiac Wall Thickness

Pulse-echo ultrasound, a valuable tool for noninvasive cardiac examination, has been used extensively to determine left ventricular volume and wall thickness. It is often difficult, however, to visualize simultaneously the endocardial and epicardial surfaces of the left ventricular posterior wall because of dynamic range and grey scale limitations. Although the signal reflected at the epicardial-lung interface is much stronger than the signal from surrounding myocardium and lung, it is often obliterated when the receiver gain is increased sufficiently to record the endocardial echo. We have developed a switched gain technique which allows both wall surfaces to be visualized in real time. An oscillator rapidly switches the receiver gain between two levels that are independently set to display the two wall surfaces; thus, echograms are generated with high and low gain portions closely mixed. The endocardial surface is seen best at high gain; the epicardial surface at lower amplification.
Popular Mobilization in Mexico: The Teachers' Movement 1977–87

This book explores the process of popular mobilisation in contemporary Mexico through the experience of the country's most important popular organisation - the teachers' movement. It creates a distinctive perspective on Mexican politics and makes an interesting contribution to the study of popular or 'social' movements. This in-depth study of a popular movement in Latin America provides a richly detailed account of its organisation, leadership, strategic choices, and factional divisions. Through its innovative methods, which produce an unusual and compelling blend of fact and theory, the book uncovers the motivations and mechanisms of popular mobilization, as well as explaining its interactions with national politics in Mexico and beyond.
SOLVING SYSTEMS OF LINEAR EQUATIONS OVER POLYNOMIALS

We consider a system of linear equations of the form A(x)X(x) = b(x), where A(x), b(x) are given m × n and m × 1 matrices with entries from Q[x], the ring of polynomials in the variable x over the rationals. We provide a polynomial-time algorithm to find the general solution of this system over Q[x]. This is accomplished by devising a polynomial-time algorithm to find the triangular canonical form (Hermite form) of the matrix A(x) using unimodular column operations. As applications we are able to give polynomial-time algorithms for finding the diagonal (Smith canonical) form of a polynomial matrix, testing whether two given matrices of rational entries are similar and for finding the invariant factors of a matrix of rationals.
Serotonin-induced dilation of small arterioles is not mediated via endothelium-derived relaxing factor in skeletal muscle.

Serotonin (5-HT) dilates precapillary arterioles in skeletal muscle. The purpose of this study was to determine if 5-HT releases endothelium-derived relaxing factor (EDRF) in this tissue. Diameters of third-order arterioles (A3) in the cremaster muscle of pentobarbital-anesthetized rats were measured via videomicroscopy. Concentration-response curves for acetylcholine, nitroprusside and 5-HT were obtained before and after the application of either hydroquinone (5 x 10(-4) M) or NG-nitro-L-arginine (10(-4) M). The involvement of prostaglandins was eliminated by ibuprofen (10(-4) M). In one group, 5-HT (20 micrograms/kg) and NG-nitro-L-arginine were given i.v. (30 mg/kg). The non-EDRF-dependent vasodilator papaverine (10(-5) M) was applied at the end of the protocol to determine the maximal resting diameter. When applied topically, both hydroquinone and NG-nitro-L-arginine significantly inhibited the dilation induced by acetylcholine, but neither agent affected the dilation to nitroprusside or 5-HT. NG-Nitro-L-arginine (i.v.) attenuated acetylcholine-induced dilation but not the dilation to intravenous 5-HT. These data suggest that 5-HT-induced dilation of small arterioles in skeletal muscle is EDRF-independent.
Strengthening Multisite Educational Interventions: An Illustration With Multilevel Modeling

This article illustrates the value and use of multilevel models to examine site-to-site outcome differences in the analysis of data from multisite evaluations. It shows how a traditional analysis approach can overlook effective interventions and miss important links between program implementation and outcomes. Practical issues regarding statistical power and intervention leakage are also discussed. Using data from an evaluation of an alternative teacher certification program, this illustration finds site-to-site outcome differences and shows how program developers can exploit these differences in an attempt to understand and strengthen an intervention.
Studies of Dirhodium Tetra(trifluoroacetate). 3. Solid State Isomers of the Compound Rh2(O2CCF3)4(THF) Prepared by Sublimation

The monoadduct of dirhodium tetra(trifluoroacetate) with THF has been obtained by deposition from the vapor phase. The compound Rh2(O2CCF3)4(THF) crystallizes in two isomeric forms, 1 and 2, whose structures have been determined by X-ray crystallography. The crystallographic parameters are as follows: for 1, triclinic space group P1 with a = 9.557(2) A, b = 10.126(2) A, c = 11.840(4) A, α = 95.97(2)°, β = 90.40(2)°, γ = 115.58(1)°, and Z = 2; for 2, triclinic space group P1 with a = 8.6347(3) A, b = 9.678(1) A, c = 13.773(4) A, α = 73.182(5)°, β = 74.622(5)°, γ = 89.76(1)°, and Z = 2. Compound 1 is unique as the only extended structure where dirhodium carboxylate molecules are bridged by a single exogenous atom. The oxygen atom of the THF ligand coordinates to the axial positions of two Rh2 units so that a one-dimensional zigzag chain is formed. The bridging is slightly asymmetric with Rh−O(THF) distances of 2.363(6) and 2.407(6) A, and the Rh−O(THF)−Rh angle is 111.8(3)°. The crystal structure of 2 is...
Ion-Molecule Reactions in Isopropanol: Implications for Its Radiolysis.

The photoionization of isopropanol (i-PrOH) at 11.7 eV has been investigated in the NBS high pressure photoionization mass spectrometer over the pressure range 0.1 to approximately 200 millitorr. The major primary ion, CH3CHOH+, reacts with a total rate coefficient of 1.1 ±0.1× 10-9 cm3/mole-cule-s to yield mainly (i-PrOH)H+ and CH3(i-C3 H7)COH+. At pressures in excess of a few millitorr consecutive reactions of (i-PrOH)H+ and CH3(i-C3H7)COH+ were also detected, including the overall dehydration process (i-PrOH)H++i-PrOH→H2O+(i-C3H7)2OH+ These data are interpreted in light of a recent radiolysis study, and a thermal cationic chain mechanism for production of (I-C3H7)2O consistent with those results is proposed. The value for the proton affinity of SF6 is also discussed in some detail.
Neuropsychologic effects of stroke in children with sickle cell anemia

We examined the nature and extent of neuropsychologic impairment in chilldrenwith sickle cell anemia (SCA) with or without stroke. Twenty-nine children with SCA received cranial magnetic resonance imaging. Strokes were classified into three groups: diffuse cortical stroke (n=11), anterior stroke (n=6), or none (n=12). Children with SCA and 20 age-matched sibling control subjects then recelved a neurologic examination and a neuropsychologic battery of tests that included motor, verbal, spatial, attentional, and memory measures. Tests of spatial function showed that children with diffuse cortical strokes were impaired, whereas children with anterior lesions had intrusions of irrelevant material during list recall. There were no significant differences between children with stroke and sibling control subjects on motor, verbal, or memory measures. Six children had evidence of stroke on magnetic resonance imaging without any history of a damaging neurologic event. These children had impaired neuropsychologic performance relative to that of sibling control subjects in a pattern similar to that of children with overt stroke. Children with SCA without stroke did not differ from sibling control subjects on any measure. Our results indicate that overt and silent strokes result in lesion-specific neuropsychologic deficits in children with SCA.
Introduction of a second-rank antisymmetric tensor into null aesthetic field theory

We are able to incorporate an antisymmetric second-rank tensor into null aesthetic field theory. There are some changes in the solutions due to the introduction of this antisymmetric second-rank tensor, which we discuss. We are not able to find an acceptable bounded particle system in four space-time dimensions.
Effects of Substitutions in a Conserved DX2GR Sequence Motif, Found in Many DNA-dependent Nucleotide Polymerases, on Transcription by T7 RNA Polymerase

The region in bacteriophage T7 RNA polymerase (RNAP) comprising residues 421-425 contains a sequence motif (DX(2)GR) that is conserved among many DNA-dependent nucleotide polymerases. We have found that alterations in this motif result in enzymes that display weaker retention of the RNA product during transcript initiation, a decreased ability to make the transition to a stable elongation complex, and changes in substrate binding and catalytic activity. Many of these defects are coupled with an altered response to the presence or absence of the non-template strand. The observed constellation of defects supports a role for the motif in interacting with and stabilizing the RNA:DNA hybrid during the early stages of transcript initiation. This is consistent with the position of the motif in a T7 RNAP initiation complex. Although a conserved DX(2)GR sequence motif is also observed in multisubunit RNAPs, the structural organization of the motif and the manner in which it interacts with the RNA:DNA hybrid in the latter enzymes is different from that in T7 RNAP. However, another element in the multisubunit RNAPs that contains a highly conserved arginine residue may play the same role as R425 in T7 RNAP. (c) 2002 Elsevier Science Ltd.
Oncology Nurses' Knowledge of Survivorship Care Planning: The Need for Education

Purpose/objectives To survey nurses about their knowledge of cancer survivorship care. Design Descriptive, cross-sectional. Setting Midwestern comprehensive cancer center. Sample 223 registered and advanced practice nurses. Methods Online survey of survivorship knowledge using a 50-item questionnaire derived from the Institute of Medicine report and related publications. Main research variables Concepts of survivorship care and common long-term symptoms. Findings Most nurses reported having knowledge about healthy lifestyle habits; more than 50% of nurses reported having knowledge about chemotherapy, surgery, and radiation therapy, as well as side effects of fatigue, depression, limitations of daily activities, and weight gain; less than 50% of nurses reported having knowledge of impact on family, biologic agents, lymphedema, immunizations or vaccinations, and osteoporosis screening; less than 40% of nurses reported having knowledge about marital and partner relationships, osteoporosis prevention and care, sexuality, side effects of bone marrow transplantation, employment issues, and angiogenesis agents; and less than 25% of nurses reported having knowledge on genetic risks, as well as fertility, financial, and insurance issues. Conclusions Oncology nurses at an academic comprehensive cancer center reported gaps in knowledge consistent with previous studies about knowledge of survivorship care. Implications for nursing The Institute of Medicine has challenged oncology providers to address cancer survivorship care planning. Gaps in cancer survivorship knowledge are evident and will require focused education for this initiative to be successful.
Normal ocular circulation and the effect of arterial occlusive disorders

Arterial occlusive disease, either primary or secondary, may not only affect the appearance of the ophthalmic artery, posterior ciliary arteries, and choroid crescent, but may be reflected in the prolongation of the circulation time to the choroid crescent. Choroid circulation time determined in 80 normal carotid angiograms showed that a value greater than 4.5 sec. for a population under 30 years of age, and greater than 5.6 sec. for a population 30 years of age and older, is prolonged. One should view these studies with suspicion and search for intra-orbital, intracranial, or extracranial arterial occlusive disease.
CELLULAR NARCOSIS OF PARAMECIUM MULTIMICRONUCLEATUM BY XENON AND OTHER CHEMICALLY INERT GASES.

SYNOPSIS. Xenon applied at sufficient pressures ranging from 30 pounds per square inch to 225 p.s.i. caused reduction in contractile vacuole activity, increase in cellular volume, expansion of the surface region, cessation of forward movement, and cytolysis of paramecia. Krypton at 915 p.s.i. prevented contractile vacuole activity, but forward movement continued for at least 30 min. When subjected to 115 p.s.i. of N2O, paramecia moved in slow oscillations, and contractile vacuoles failed to empty. At 265 p.s.i. of N2O movement ceased and cytolysis resulted. The pressure required to terminate movement in the same time interval following application of the pressure was less for N2O than for xenon. The expansion of the surface of the cells suggests that inert gases produce narcosis by dissolving into this region.
Sleep duration and reported functional capacity among black and white US adults.

Objective:Evidence suggests that individuals reporting sleeping below or above the population's modal sleep duration are at risk for diabetes, hypertension, and other cardiovascular diseases. Evide...
Schedules of reinforcement and individual differences in learning and recall.

To test hypotheses derived from the Alternative Response Model of “defense mechanisms,” three different types of responders to adequacy material were studied in a paired-associate learning and recall paradigm under three different patterns of reinforcement. Differences in response patterns to specific reinforcement conditions between Direct-relevant Responders (conflict-free) and the ether two groups of Ss (Indirect-relevant and Non-relevant Responders) were found. The results were only partially consistent with the predictions and previous results. However, the results for the learning task and the recall task were different from each other. Several problems deriving from the particular experimental paradigm used were evident. Further programmatic research was suggested.
Progesterone, Progestins and 17-Hydroxypregn-4-ene-3,20-dione in the Utero-ovarian Uterine and Peripheral Blood of the Pregnant Rhesus Monkey

Progesterone, progestins, and 17-hydroxypregn-4-ene-3,20-dione (17-OHP) were measured in the utero-ovarian, uterine and peripheral plasma at days 22, 42, and 157 of pregnancy in the rhesus monkey (Macaca mulatta). At day 22, the concentrations of these steroids in the utero-ovarian vein were higher than in the uterine vein, and the titers in both of these vessels were higher than those in the periphery. At day 42, the quantities of progesterone, progestins and 17-OHP in the utero-ovarian vein were not elevated over uterine vein levels but hormone levels in both of these vessels were higher than peripheral titers, although progesterone and progestins in the utero-ovarian and uterine veins were not elevated as markedly over peripheral concentrations at day 42 as at day 22. At day 157, progesterone and progestins were higher in the uteroovarian vein than in the uterine vein and their concentrations in both vessels were considerably elevated over peripheral blood levels. Little 17-OHP was present at day 157. ...
A new method for stable lead isotope extraction from seawater

A new technique for stable lead (Pb) isotope extraction from seawater is established using Toyopearl AF-Chelate 650M(®) resin (Tosoh Bioscience LLC). This new method is advantageous because it is semi-automated and relatively fast; in addition it introduces a relatively low blank by minimizing the volume of chemicals used in the extraction. Subsequent analyses by HR ICP-MS have a good relative external precision (2σ) of 3.5‰ for (206)Pb/(207)Pb, while analyses by MC-ICP-MS have a better relative external precision of 0.6‰. However, Pb sample concentrations limit MC-ICP-MS analyses to (206)Pb, (207)Pb, and (208)Pb. The method was validated by processing the common Pb isotope reference material NIST SRM-981 and several GEOTRACES intercalibration samples, followed by analyses by HR ICP-MS, all of which showed good agreement with previously reported values.
On the weak convergence of an ergodic iteration for the solution of variational inequalities for monotone operators in Hilbert space

Throughout, H denotes a real Hilbert space with inner product (., .), C a nonempty closed convex subset of H, and A a multivalued monotone operator with domain D(A) 3 C. (That is, A is a subset of H x H with the property that whenever [xi , zui] E A for i = 1,2, then (wr wa , x1 XJ > 0. By definition A(x) = {w E H: [.x, w] E A} and D(A) = {x: A(x) # a).) We denote by E the set of solutions u E C of the variational inequality
Mesostructured MTES-Derived Silica Thin Film with Spherical Voids Investigated by TEM: 1. Mesostructure Determination

The mesostructure of a hydrophobic silica thin film with spherical voids arranged in an ordered array was investigated and resolved thoroughly by transmission electron microscopy (TEM). The novel TEM approach involved sample tilting to get different zone axes and simulation, as well as the calculation of plane spacings and angles for comparison of the experimental values with the corresponding theoretical ones. The camera constant (λL) was calibrated carefully by the diffraction pattern of the silicon substrate, on which the closed-cell mesostructured thin film was developed. This film was fabricated by solvent evaporation-induced sol−gel and self-assembly processes, with methyl triethoxysilane [MTES, Si(OCH2CH3)3CH3] as the silica precursor and a polystyrene-block-poly(ethylene oxide) diblock as the structure-directing agent; pyrolysis was performed carefully to remove the template. The present TEM exploration concludes that the mesostructure is exclusively body-centered cubic (bcc) rather than face-cent...