cssi/SciSciGPT-SciSciNet huggingface dataset:
Government Guidelines Versus Image Quality In Chest Radiography

AbstractRecent Federal guidelines for radiation protection specify maximum exposure limits for certain radiological examinationsperformed in Federal institutions. For example, the maximum entrance skin exposure for a P.A. chest (23 cm) is recommendedto be 30 milliroentgen, These guidelines, however, leave the criterion of image quality to the discretion of the institution.An investigation was done using an anthropomorphic chest phantom with simulated ponary nodules and pneumonia. Aseries of chest radiographs were produced at various entrance exposures by altering kilovoltage and image receptor. The exposures ranged from 5 mR to 65 mR. The variation of image quality obtainable within this range was categorized as leastacceptable, acceptable, and most acceptable by three observers. The range of acceptability is correlated with entranceskin exposure.Introduction and BackgroundIt is well known by those concerned with radiation protection that exposure due to medical uses of ionizing radiation repre-sents a significant and growing source of exposure for North American populations and is also one that can be reduced bygood practice. In an effort to maintain radiation doses as low as practicable, the U.S. Federal government recently issuedrecommendations regarding radiation protection in Federal agencies for diagnostic x- rays.(1.2) There are plans to extendthese recommendations to all areas of medical radiology. Contained within these recommendations are exposure guidelinesfor selected routine x -ray examinations of a reference patient. Survey data of Federal institutions from the NEXT programindicates that exposures in the upper 25% of the exposure frequency distribution (fourth Quartile) are unnecessarily excessiveand could be reduced to the third quartile or lower with appropriate technique changes.(3,4)A search of the recent literature revealed no study on the effect these exposure guides may have on radiographic image
Comparison of actual and linearly extrapolated dissociation energies of diatomic molecules

Abstract Actual dissociation energies D0 and values linearly extrapolated from vibrational data Dlin are compared for the ground states of 98 diatomic molecules. These molecules meet the following criteria: there is no significant uncertainty in ground state identification, D 0 D lin is accurate to 5%, and Dlin is not from head data constants (except Q heads) or an empirical model or formula. The primary means of classifying molecules is through relative location of constituent atoms in the periodic table. The average D 0 D lin is 0.74 ± 0.05 for homonuclear molecules and 0.75 ± 0.08 if both atoms are distinct but from the same periodic table column. Average ratios as a function of constituent atom periodic table separation are: 0.91 ± 0.10 if one column apart, 0.97 ± 0.06 two columns, 1.03 ± 0.12 three columns, 1.48 ± 0.16 four columns, and 1.87 ± 0.29 six columns. An overall trend with ionicity is, thus, clear. However, variations within each class are significant; for example, a tendency for D 0 D lin to decrease with increasing atomic size is noted for non-metals. For hydrides, the average D 0 D lin is 0.92 ± 0.08. The ratio for strongly bound molecules with a Group II constituent is lower than would be expected if both atoms had open subshells, due presumably to excited state contributions. The average D 0 D lin for eight ionized molecules is 0.99 with individual values varying from 0.84 to 1.18. Generally, removal of an electron from a neutral molecule increases D 0 D lin by ∼ 25%. However, in going from CO to CO+ the ratio drops from 1.02 to 0.84. When Di, the dissociation energy to ions, is compared to Dlin for the alkali halides, the average D i D lin = 2.50 with almost no scatter. For Group III halides, the average D i D lin = 2.27 ± 0.14 . A discussion of D 0 D lin or D i D lin for three theoretical models is included for comparison with actual molecules.
The Use of Small Groups in Computer-Based Training: A Review of Recent Literature.

Abstract A review of recent work in small-group computer-based training (CBT) reveals that using small groups in CBT does not seem to harm achievement but does not necessarily lead to higher achievement, as would be expected from related literature. However, many small-group CBT studies have one or more methodological weaknesses. Several small-group subfactors affect small-group CBT achievement. With regard to individual group member aptitude, the literature is inconclusive on group composition. Optimum group size seems to be either two or three, and group members should usually be of the same gender. The most promising research area seems to be the behavior of the members of the small group while they are involved in CBT. If proper behavioral guidance and structure can be provided to group members, using small groups in CBT should lead to higher achievement than individual CBT.
The Catalina Eddy and its Effect on Pollution over Southern California

Abstract A case study of a Catalina Eddy during Project BASIN is presented. There appears to he a topographic influence in the generation of this eddy. Detailed surface and upper-air data over Los Angeles illustrate the effect of the eddy on the boundary layer and on the transport of ozone out of the basin. Isentropic analyses are consistent with visual satellite images of the phenomena. The Catalina Eddy was shown to extend throughout the entire depth of the strong temperature inversion that exist over Los Angeles, with maximum wind speeds within the inversion. Surface ozone levels downwind of the eddy are shown to vary depending on the local circulations.
Simulation of Tokamak Divertor Plasmas including Cross-Field Drifts

The effects of plasma currents and cross-field drifts on single null tokamak divertor operation are simulated using a fully implicit 2-D fluid code. Equations solved are those for particle continuity, parallel momentum, electron energy, ion energy, electrostatic potential, and neutral gas diffusion. The core and scrape-off layer regions are separated by a magnetic separatrix, both of which are included in the simulation. The core plasma is poloidally periodic, and the inner and outer private flux regions are properly connected. The code utilizes a fully implicit method-of-lines scheme to advance the variables in time with a Krylov technique or a direct Newton iteration with a numerical Jacobian. Results are presented on the effects of currents and cross-field drifts for DIII-D single-null parameters.
DRIVE: a tool for developing, deploying, and managing distributed sensor and actuator applications

This paper introduces Distributed Responsive Infrastructure-Virtualization Environment (DRIVE), a tool that provides both an integrated development environment (IDE) and an execution environment and thus supports the entire life cycle of sensor/actuator applications. Developers are only responsible for implementing the core event-handling logic, whereas DRIVE generates the necessary code for message passing and invocation, thus reducing the development skills required. The development methodology, which is component based and model driven, separates the solution model, which captures the business logic, from the deployment model, which reflects the physical computing infrastructure. This allows the administrators to configure and deploy applications on various infrastructure topologies. To illustrate the benefits of DRIVE, we present an example application, dock-door receiving, and show the ways in which DRIVE supports the modeling and development of the application logic and the multiphase deployment of the resulting application in a production environment.
Supercritical CO2 intercalation of layered silicates

Abstract In this study, we use supercritical CO 2 as the processing medium for intercalating the structure of natural clay, Cloisite Na + , and depositing CO 2 -philic sugar acetate, β- d -galactose pentaacetate, between the layers of the clay. Based on our measurements of the phase behavior of the β- d -galactose pentaacetate–CO 2 system, we select two processing conditions: a dense gas solution (DGS) at 40 °C and 11.7 MPa with 2.4 wt.% sugar acetate in CO 2 and a gas-expanded liquid (GEL) at 40 °C and 7.9 MPa with 6.1 wt.% sugar acetate in CO 2 . The morphology of the as-received natural clay and clay samples processed under the DGS and the GEL conditions is determined by wide-angle X-ray diffraction (XRD), transmission electron microscopy (TEM) and low-energy electron diffraction (LEED) methods. The XRD results indicate intercalation of the clay layers. While the ordered structure remains, the gallery spacing between Cloisite Na + layers is doubled, from 0.3 1 to 0.52 and 0.59 nm for DGS- and GEL-processing conditions, respectively. The LEED patterns of the processed clays show bright spots characteristic of the highly crystalline sugar acetate superimposed on the halo pattern of the clay, confirming the deposition of the sugar acetate in the intercalated structure of the clay after scCO 2 processing.
Rabies Virus Infection Induces Type I Interferon Production in an IPS-1 Dependent Manner While Dendritic Cell Activation Relies on IFNAR Signaling

As with many viruses, rabies virus (RABV) infection induces type I interferon (IFN) production within the infected host cells. However, RABV has evolved mechanisms by which to inhibit IFN production in order to sustain infection. Here we show that RABV infection of dendritic cells (DC) induces potent type I IFN production and DC activation. Although DCs are infected by RABV, the viral replication is highly suppressed in DCs, rendering the infection non-productive. We exploited this finding in bone marrow derived DCs (BMDC) in order to differentiate which pattern recognition receptor(s) (PRR) is responsible for inducing type I IFN following infection with RABV. Our results indicate that BMDC activation and type I IFN production following a RABV infection is independent of TLR signaling. However, IPS-1 is essential for both BMDC activation and IFN production. Interestingly, we see that the BMDC activation is primarily due to signaling through the IFNAR and only marginally induced by the initial infection. To further identify the receptor recognizing RABV infection, we next analyzed BMDC from Mda-5−/− and RIG-I−/− mice. In the absence of either receptor, there is a significant decrease in BMDC activation at 12h post infection. However, only RIG-I−/− cells exhibit a delay in type I IFN production. In order to determine the role that IPS-1 plays in vivo, we infected mice with pathogenic RABV. We see that IPS-1−/− mice are more susceptible to infection than IPS-1+/+ mice and have a significantly increased incident of limb paralysis.
Residues of E. coli topoisomerase I conserved for interaction with a specific cytosine base to facilitate DNA cleavage

Bacterial and archaeal topoisomerase I display selectivity for a cytosine base 4 nt upstream from the DNA cleavage site. Recently, the solved crystal structure of Escherichia coli topoisomerase I covalently linked to a single-stranded oligonucleotide revealed that R169 and R173 interact with the cytosine base at the -4 position via hydrogen bonds while the phenol ring of Y177 wedges between the bases at the -4 and the -5 position. Substituting R169 to alanine changed the selectivity of the enzyme for the base at the -4 position from a cytosine to an adenine. The R173A mutant displayed similar sequence selectivity as the wild-type enzyme, but weaker cleavage and relaxation activity. Mutation of Y177 to serine or alanine rendered the enzyme inactive. Although mutation of each of these residues led to different outcomes, R169, R173 and Y177 work together to interact with a cytosine base at the -4 position to facilitate DNA cleavage. These strictly conserved residues might act after initial substrate binding as a Molecular Ruler to form a protein-DNA complex with the scissile phosphate positioned at the active site for optimal DNA cleavage by the tyrosine hydroxyl nucleophile to facilitate DNA cleavage in the reaction pathway.
Positive and negative affectivity for academic and interpersonal domains: relations to general affectivity, extraversion, and neuroticism

Abstract The present study examined the relations between positive and negative affectivity for academic and interpersonal domains with a measure of general affectivity. Results of within-group analyses of variances indicated that scores on measures of positive and negative affectivity for academic situations were significantly different compared with scores for interpersonal and general affectivity. Consistent with previous research, measures of general positive and negative affectivity were found to remain significantly associated with measures of extraversion and neuroticism, respectively, even after controlling for domain-specific affectivity. Overall, the present findings indicate that emotional experience might differ considerably across different domains.
Of mice and men: Fossil-based divergence dates and molecular “clocks”

Abstract The magnitude of immunological differences between species has been used to estimate the time of divergence of lineages, especially among primates. Calibration of “clocks” based on immunological differences has relied heavily on data from Pakistan suggest that the lineages leading to Mus and Rattus diverged between 14 and 8 million years ago rather than 30 or more million years ago as suggested by techniques invoking constant rates of molecular evolution. Molecular analyses of pairs of mammal species which appear well documented paleontologically should be undertaken in order to expand our understanding of the tempo and mode of molecular evolution.
Production of 10BeO targets via the 13C(n, α)10Be reaction

Abstract Pyrolitic graphite enriched to 90% in 13 C has been irradiated with fast neutronsto make beryllium enriched to 94% in 10 Be. The technical aspects of this process and the fabrication of 10 Be into thin BeO targets for use in nuclear spectroscopy is described.
Pathophysiology of Activity Limitation in Patients With Interstitial Lung Disease

Objective To analyze the relative importance of gas exchange, ventilatory, and circulatory abnormalities in limiting exercise in patients with interstitial lung disease. Design and setting Retrospective study at a referral cardiopulmonary exercise laboratory in a university/county medical center. Patients and methods A database with more than 1,300 patients with incremental cycle exercise studies was screened to find 42 patients with interstitial lung disease, but without accompanying airflow limitation, chest wall, primary heart, or systemic vascular disease, or poor motivation. All had spirometry, lung volume, and gas transfer index measures at rest and repeated gas exchange, ventilatory, and circulatory measures during exercise; 37 of the 42 patients had multiple blood gas measures during exercise. We graded the gas exchange, ventilatory, and circulatory dysfunction during maximally tolerated cycle ergometry and correlated the grades of dysfunction of these three components of respiration with percent predicted peak O 2 uptake (peak Vo 2 ). Results Peak V0 2 values were not well correlated with the grades of ventilatory impairment but were well correlated with the grades of gas exchange and circulatory dysfunction. Patients who had reduced peak V0 2 values often had a normal breathing reserve with physiologic evidence of pulmonary vascular disease. Conclusions The pathophysiology of the pulmonary circulation is usually more important than ventilatory mechanics in limiting exercise in patients with interstitial lung disease.
Cemeteries as Indicators of Post-Settlement Anthropogenic Soil Degradation on the Atlantic Coastal Plain

Over the past ca. 350 years, anthropogenic activities on the Mid-Atlantic Coastal Plain have caused considerable soil erosion and degradation due to deforestation, intensive agriculture, and poor if any soil conservation practices. Early colonial descriptions indicated rich soils suitable for agriculture supported by the rapid deforestation for cultivation. Small, undisturbed family cemeteries on the Lower Eastern Shore of Maryland provided valuable markers for assessing these changes. Continued cultivation around the cemeteries has left many of them as isolated remnant knolls, elevated above the surrounding fields. Four cemetery sites were sampled in Wicomico Co., on Maryland’s Lower Eastern Shore. Topographic data for the four sites was collected using a laser-guided total station and 3-D topographic models were generated. Composite soil samples were collected from each cemetery and two locations in the adjoining field. The physical and chemical properties indicated that the cemeteries were left in situ largely undisturbed by human activities for a prolonged period. The fields surrounding the cemeteries, however, exhibited 0.43 to 0.52 m of surface soil depletion, lower organic matter, soil carbon, total nitrogen, but higher level of cations such as Ca and K, the result of liming and fertilization. Our results were consistent with our hypothesis that land clearance and farming practices have considerably eroded and altered the chemistry and structure of soils on the Lower Eastern Shore of Maryland.
Addressing Children's Communication Needs

Purpose In this column, the editor gives an overview of each article in the current issue of Language, Speech, and Hearing Services in Schools (Vol. 45, No. 3).
Bowman-Birk inhibitor attenuates dystrophic pathology in mdx mice.

Bowman-Birk inhibitor concentrate (BBIC), a serine protease inhibitor, has been shown to diminish disuse atrophy of skeletal muscle. Duchenne muscular dystrophy (DMD) results from a loss of dystrophin protein and involves an ongoing inflammatory response, with matrix remodeling and activation of transforming growth factor (TGF)-β1 leading to tissue fibrosis. Inflammatory-mediated increases in extracellular protease activity may drive much of this pathological tissue remodeling. Hence, we evaluated the ability of BBIC, an extracellular serine protease inhibitor, to impact pathology in the mouse model of DMD (mdx mouse). Mdx mice fed 1% BBIC in their diet had increased skeletal muscle mass and tetanic force and improved muscle integrity (less Evans blue dye uptake). Importantly, mdx mice treated with BBIC were less susceptible to contraction-induced injury. Changes consistent with decreased degeneration/regeneration, as well as reduced TGF-β1 and fibrosis, were observed in the BBIC-treated mdx mice. While Akt signaling was unchanged, myostatin activitation and Smad signaling were reduced. Given that BBIC treatment increases mass and strength, while decreasing fibrosis in skeletal muscles of the mdx mouse, it should be evaluated as a possible therapeutic to slow the progression of disease in human DMD patients.
Are there pancreatic progenitor cells from which new islets form after birth

Although pancreatic islet transplantation can restore normal β-cell function to patients with diabetes, success is limited by tissue availability. An alternative strategy is to stimulate development of the patients' own β cells; however, the postnatal origin of new β cells remains controversial. This Viewpoint proposes that progenitor cells could exist in the pancreatic ducts.
"YOU TRY TO BE SUPERMAN AND YOU DON'T HAVE TO BE": GAY ADOPTIVE FATHERS' CHALLENGES AND TENSIONS IN BALANCING WORK AND FAMILY

A body of literature has emerged that focuses on work-family balance among heterosexual fathers. Little attention has been paid to how gay fathers balance work and family, despite the reality that they too are likely affected by similar masculine norms. The current qualitative study of 70 gay adoptive fathers (35 couples) begins to fill this gap in the literature. Analyzing interview data through the lens of Voydanoff’s (2005) work-family fit and balance model, we examine the ways in which gay men’s experiences of work-family balance are both constrained and enhanced by particular demands and resources. Highlighting the role of gender and sexual orientation, we analyze the challenges these men face and the strategies they use to cope with work-family tensions.
Impact on Stroke Subtype Diagnosis of Early Diffusion-Weighted Magnetic Resonance Imaging and Magnetic Resonance Angiography

Background and Purpose—The purpose of the present study was to assess the diagnostic usefulness of early diffusion-weighted MRI (DWI) and MR angiography (MRA) in patients with ischemic stroke. Past approaches to stroke diagnosis required a series of diagnostic tests over several days of hospitalization. New magnetic resonance methodologies that include DWI and MRA may allow more rapid characterization of stroke pathophysiology. However, no previous study has assessed the impact on formal stroke subtype diagnosis of early imaging with DWI/MRA. Methods—We analyzed 46 consecutive patients with acute ischemic stroke who underwent DWI/MRA within 24 hours of admission. Initial diagnoses were rendered with use of the 2 most widely used formal stroke subtype classification schemes, the TOAST and the Oxfordshire methods, which were applied to patients after CT/conventional MRI but before DWI/MRA. Modified TOAST and Oxfordshire diagnoses were then rendered based on the results of day 1 DWI, MRA, and DWI plus MRA. F...
Atomic shell structure in Hartree-Fock theory

Abstract The radial density distribution function computed from the spherically averaged numerical Hartree—Fock density is found to reveal distinct topological features characteristic of the shell structure of atoms beyond Ar for which hitherto reported studies based on the analytical Hartree—Fock density do not show the formal shell structure. Based on the numerical evidence, the location of the midpoint corresponding to the last two successive points of inflection in the distribution function is proposed to define the core—valence separation for heavier atoms ( Z ⩾19).
Optimal scheduling in a multiserver stochastic network

We consider a fundamental scheduling problem in a multiserver stochastic network consisting of 2 classes of customers and 2 classes of servers. Customers of class k arrive to queue k according to a Poisson process with rate λk, k = 1, 2. The service times of class k customers at class e servers are i.i.d. following an exponential distribution with mean μke-1, ∀k, e = 1, 2, where 0
Critical reflective thinking through service‐learning in multicultural teacher education

This paper describes and discusses the effect of service‐learning on students’ reflective thinking about their own knowledge in multicultural teacher education at a state university in Southern California (USA). Two versions of students’ multicultural autobiographies, one at the beginning and the other at the end of the course, were examined to determine their individual progress. Two classes, one with a service‐learning assignment and the other without, were involved to identify differences. Using King and Kitchener’s model of reflective judgment, this study compares and contrasts the progress of student critical reflective thinking and differences between the two classes. The research suggests that service‐learning stimulated and increased students’ reflective thinking about their own knowledge in multicultural education.
About some biochemical properties of dimethylsulfoxide and three of its homologues: Is the acidic function essential for nonsteroidal antiinflammatory activities?

Dimethylsulfoxide and three related sulfoxides exhibit some of the biochemical properties of classical non steroidal antiinflammatory acidic drugs. Thusn-propyl sulfoxide,n-butyl sulfoxide and tetramethylene sulfoxide stimulate O2 consumption by rat liver mitochondria. These 3 compounds induce mitochondrial swelling. Lymphocyte welling is only induced by high doses ofn-propyl sulfoxide andn-butyl sulfoxide and not by tetramethylene sulfoxide.
Mycobacterium tuberculosis NmtR Harbors a Nickel Sensing Site with Parallels to Escherichia coli RcnR

Mycobacterium tuberculosis NmtR is a Ni(II)/Co(II)-sensing metalloregulatory protein from the extensively studied ArsR/SmtB family. Two Ni(II) ions bind to the NmtR dimer to form octahedral coordination complexes with the following stepwise binding affinities: K(Ni1) = (1.2 ± 0.1) × 10(10) M(-1), and K(Ni2) = (0.7 ± 0.4) × 10(10) M(-1) (pH 7.0). A glutamine scanning mutagenesis approach reveals that Asp91, His93, His104, and His107, all contained within the C-terminal α5 helix, and His3 as part of the conserved α-NH(2)-Gly2-His3-Gly4 motif at the N-terminus make significant contributions to the magnitude of K(Ni). In contrast, substitution of residues from the C-terminal region, His109, Asp114, and His116, previously implicated in Ni(II) binding and metalloregulation in cells, gives rise to wild-type K(Ni) and Ni(II)-dependent allosteric coupling free energies. Interestingly, deletion of residues 112-120 from the C-terminal region (Δ111 NmtR) reduces the Ni(II) binding stoichiometry to one per dimer and greatly reduces Ni(II) responsiveness. H3Q and Δ111 NmtRs also show clear perturbations in the rank order of metal responsiveness to Ni(II), Co(II), and Zn(II) that is distinct from that of wild-type NmtR. (15)N relaxation experiments with apo-NmtR reveal that both N-terminal (residues 2-14) and C- terminal (residues 110-120) regions are unstructured in solution, and this property likely dictates the metal specificity profile characteristic of the Ni(II) sensor NmtR relative to other ArsR family regulators.
Measurement of Intrinsic Rate Constants in the Tyrosine Hydroxylase Reaction

Tyrosine hydroxylase (TyrH) is a pterin-dependent mononuclear non-heme aromatic amino acid hydroxylase that catalyzes the conversion of tyrosine to dihydroxyphenylalanine (DOPA). Chemical quench analyses of the enzymatic reaction show a burst of DOPA formation, followed by a linear rate equal to the kcat value at both 5 and 30 °C. The effects of increasing solvent viscosity confirm that kcat is ∼84% limited by diffusion, most probably due to slow product release, and that tyrosine has a commitment to catalysis of 0.45. The effect of viscosity on the kcat/Km for 6-methyltetrahydropterin is greater than the theoretical limit, consistent with the coupling of pterin binding to the movement of a surface loop. The absorbance changes in the spectrum of the tetrahydropterin during the first turnover, the kinetics of DOPA formation during the first turnover, and the previously described kinetics for formation and decay of the Fe(IV)O intermediate [Eser, B. E., Barr, E. W., Frantom, P. A., Saleh, L., Bollinger, J. ...
Burnout in residents of otolaryngology-head and neck surgery: a national inquiry into the health of residency training.

PURPOSE To characterize resident burnout on a national scale with a large sample size and to identify associated modifiable factors to minimize burnout and improve the quality of residency education. METHOD A survey was mailed to all 1,364 U.S. residents of otolaryngology-head and neck surgery in September 2005. The main outcome measures were the Maslach Burnout Inventory-Human Services Study, demographic information, and potential burnout predictors, including stressors, satisfaction, self-efficacy, and support systems. RESULTS The response rate was 50% (684/1,364). Current second-year through fifth-year residents were included for further analysis (514). Burnout was extremely common among otolaryngology residents. High burnout was seen in 10% of residents (51), moderate burnout in 76% (391), and low burnout in 14% (72). The strongest associated demographic factor was work hours (P < .001). Hours worked was predictive of emotional exhaustion, with exhaustion scores rising by 0.19 for each hour worked (P < .001). Furthermore, there was an 8% (41 resident) reported violation rate of the Accreditation Council for Graduate Medical Education (ACGME) 80-hour-workweek limitation. Satisfaction with the balance between personal and professional life, relationship stability, and satisfaction with career choice were negatively associated with burnout (all P < .001). CONCLUSIONS Burnout is widely prevalent among U.S. otolaryngology residents and is present at greater levels than those seen in chairs or faculty of the same specialty. Work hours predict emotional exhaustion, and adherence to the ACGME 80-hour workweek may help protect against burnout and its deleterious consequences in residents of all specialties.
Design of self-diagnostic boards by multiple signature analysis

A new design approach, based on multiple signature analysis, for self-diagnostic boards is presented. For this approach, test responses from all chips on the board are compressed into space-time signatures using nonbinary multiple error-correcting codes, and faulty chips are identified by analyzing relations between distortions in these signatures. This approach results in a considerable reduction of a hardware overhead, required for diagnostics, as compared with the straightforward approach where separate signatures are computed for each chip on the board. The diagnostic approach presented can also be used for identification of faulty boards in a system or for faulty processors in a multiprocessor environment. >
Theoretical Simulation of n-Alkane Cracking on Zeolites

The kinetics of alkane cracking in zeolites MFI and FAU have been simulated theoretically from first principles. The apparent rate coefficient for alkane cracking was described as the product of the number of alkane molecules per unit mass of zeolite that are close enough to a Bronsted-acid site to be in the reactant state for the cleavage of a specific C-C bond and the intrinsic rate coefficient for the cleavage of that bond. Adsorption thermodynamics were calculated by Monte Carlo simulation and the intrinsic rate coefficient for alkane cracking was determined from density functional theory calculations combined with absolute rate theory. The effects of functional, basis set, and cluster size on the intrinsic activation energy for alkane cracking were investigated. The dependence of the apparent rate coefficient on the carbon number for the cracking of C3-C6 alkanes on MFI and FAU determined by simulation agrees well with experimental observation, but the absolute values of the apparent rate coefficients are a factor of 10 to 100 smaller than those observed. This discrepancy is attributed to the use of a small T5 cluster representation of the Bronsted-acid site. Limited calculations for propane and butane cracking on MFI reveal that significantly better agreement between prediction and observation is achieved using a T23 cluster for both the apparent rate coefficient and the apparent activation energy. The apparent rate coefficients for alkane cracking are noticeably larger for MFI than FAU, in agreement with recent findings reported in the experimental literature.
Children's Acquisition of Appropriate Norms for Friendships and Acquaintances

Research with adults demonstrates the existence of distinct norms governing the intentional giving and receiving of benefits within the context of different types of relationships. This study focuses on the development of children's adherence to these norms. We examined first and third grade children's allocation of jointly earned rewards after they had worked on a task with either an acquaintance or a friend. In both grades, more children working with friends than with an acquaintance divided the reward equally. In both grades acquaintances tended to use an equity norm more often than did friends. This effect was not significant among first graders but was significant among third graders. Moreover, third grade pairs of friends were significantly more likely than first grade pairs of friends to divide rewards equally. These results provide evidence of children's increasing use of communal norms in their friendships.
On the Necessity of Positive Semi-Definite Conductivity and Onsager Reciprocity in Modeling Heat Conduction in Anisotropic Media

It is demonstrated by a concise standard derivation, motivated by principles of rational continuum mechanics and irreversible thermodynamics augmented by novel detailed examples, that for heat conduction in linearly anisotropic solids: (1) common restrictions placed on the form of the thermal conductivity tensor are insufficient to guarantee satisfaction of the second law of thermodynamics, and (2) satisfaction of the first and second laws of thermodynamics alone is still insufficient to insure agreement between heat flow predictions and observation. An additional constraint beyond that given in many standard studies, namely that all three principal invariants of the conductivity tensor be positive semi-definite, is imposed in order to guarantee satisfaction of the entropy inequality. Thus constrained, such a theory remains under-restricted and can admit purely cyclic heat fluxes, which are not observed in nature. Imposition of the conjectures of Duhamel and Stokes, which are in fact earlier specific incarnations of Onsager's reciprocity theory, on the constitutive model relating heat flux to temperature gradient is a sufficient remedy
M-mode and two-dimensional echocardiographic findings in pulmonic valve endocarditis

1. Botvinick EH, Schiller NB, Wickramasekaran R, Klausner SC, Gertz E: Echocardiographic demonstration of early mitral valve closure in severe aortic insufficiency. Its clinical implications. Circulation 519336, 1975. 2. Wigle ED, Labrosse CJ: Sudden, severe aortic insufficiency. Circulation 32:708, 1965. 3. Meadows WR, Van Praagh S, Indreika M, Sharp JT: Premature mitral valve closure. A hemodynamic explanation for absence of the first sound in aortic insufficiency. Circulation 28:251, 1963. 4. Rees JR, Epstein EJ, Criley MJ, Ross RS: Hemodynamic effects of severe aortic regurgitation. Br Heart J 26:412, Case 1. A 24-year-old male heroine addict was hospitalized with chills, fatigue, left pleuritic chest pain, and temperature of 101.4O F. A low-frequency, early diastolic murmur was heard along the upper left sternal border. A chest x-ray film showed bilateral nodular densities consistent with septic pulmonary emboli. Blood cultures were positive for Staphylococcus aureus. An M-mode echocardiogram revealed coarse, shaggy echoes on the pulmonic valve during systole consistent with a vegetation (Fig. 1, left). The other cardiac valves appeared normal. A 2DE revealed a globular mobile vegetation on the posterior leaflet of the pulmonic valve (Fig. 1, right). Oxacillin and gentamicin were administered for 6 weeks with an excellent clinical response. A repeat 2DE at this time again showed the vegetation, although it appeared to have decreased in size. On reevaluation 17 months later the vegetation was no longer seen. 5.
Heat Shock Factor 1 Represses Transcription of the IL-1β Gene through Physical Interaction with the Nuclear Factor of Interleukin 6 *

Abstract Heat shock factor (HSF) 1 is the major heat shock transcription factor that regulates stress-inducible synthesis of heat shock proteins and is also essential in protection against endotoxic shock. Following our previous study, which demonstrated the transcriptional repression of the IL-1β gene by HSF1 (Cahill, C. M., Waterman, W. R., Xie, Y., Auron, P. E., and Calderwood, S. K. (1996) J. Biol. Chem. 271, 24874–24879), we have examined the mechanisms of transcriptional repression. Our studies show that HSF1 represses the lipopolyliposaccharide-induced transcription of theIL-1β promoter through direct interaction with the nuclear factor of interleukin 6 (NF-IL6, also known asCCAAT enhancer bindingprotein (C/EBPβ), an essential regulator inIL-1β transcription. We show for the first time that HSF1 binds directly to NF-IL6 in vivo and antagonizes its activity. The HSF1/NF-IL6 interaction involves a sequence of HSF1 containing the trimerization and regulatory domains and the bZip region of NF-IL6. HSF1 has little effect on IL-1β promoter activity stimulated by the essential monocytic transcription factor Spi.1 but is strongly inhibitory to transcriptional activation by NF-IL6 and to the synergistic activation by NF-IL6 and Spi.1. Because of its ability to bind to specific C/EBP elements in the promoters of multiple genes and its ability to interact with other transcription factors, NF-IL6 is involved in transcriptional regulation of a wide range of genes. Interaction between HSF1 and NF-IL6 could thus be an important mechanism in HSF1 regulation of general gene transcription during endotoxin stress.
Tubes in dynamical systems

Abstract Important concepts concerning tubes in dynamical systems are defined in details. In the cases of a homoclinic tube and a heteroclinically tubular cycle in autonomous systems, existence of tubular chaos is established. The main goal of this article is to stress the importance of tubes in high dimensional dynamical systems.
Pharmacokinetic Interactions between Monoamine Oxidase A Inhibitor Harmaline and 5-Methoxy-N,N-Dimethyltryptamine, and the Impact of CYP2D6 Status

5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT or street name “5-MEO”) is a newer designer drug belonging to a group of naturally occurring indolealkylamines. Our recent study has demonstrated that coadministration of monoamine oxidase A (MAO-A) inhibitor harmaline (5 mg/kg) increases systemic exposure to 5-MeO-DMT (2 mg/kg) and active metabolite bufotenine. This study is aimed at delineating harmaline and 5-MeO-DMT pharmacokinetic (PK) interactions at multiple dose levels, as well as the impact of CYP2D6 that affects harmaline PK and determines 5-MeO-DMT O-demethylation to produce bufotenine. Our data revealed that inhibition of MAO-A–mediated metabolic elimination by harmaline (2, 5, and 15 mg/kg) led to a sharp increase in systemic and cerebral exposure to 5-MeO-DMT (2 and 10 mg/kg) at all dose combinations. A more pronounced effect on 5-MeO-DMT PK was associated with greater exposure to harmaline in wild-type mice than CYP2D6-humanized (Tg-CYP2D6) mice. Harmaline (5 mg/kg) also increased blood and brain bufotenine concentrations that were generally higher in Tg-CYP2D6 mice. Surprisingly, greater harmaline dose (15 mg/kg) reduced bufotenine levels. The in vivo inhibitory effect of harmaline on CYP2D6-catalyzed bufotenine formation was confirmed by in vitro study using purified CYP2D6. Given these findings, a unified PK model including the inhibition of MAO-A- and CYP2D6-catalyzed 5-MeO-DMT metabolism by harmaline was developed to describe blood harmaline, 5-MeO-DMT, and bufotenine PK profiles in both wild-type and Tg-CYP2D6 mouse models. This PK model may be further employed to predict harmaline and 5-MeO-DMT PK interactions at various doses, define the impact of CYP2D6 status, and drive harmaline–5-MeO-DMT pharmacodynamics.
Using Gamma-Ray Burst Prompt Emission to Probe Relativistic Shock Acceleration

Abstract It is widely accepted that the prompt transient signal in the 10 keV–10 GeV band from gamma-ray bursts (GRBs) arises from multiple shocks internal to the ultra-relativistic expansion. The detailed understanding of the dissipation and accompanying acceleration at these shocks is a currently topical subject. This paper explores the relationship between GRB prompt emission spectra and the electron (or ion) acceleration properties at the relativistic shocks that pertain to GRB models. The focus is on the array of possible high-energy power-law indices in accelerated populations, highlighting how spectra above 1 MeV can probe the field obliquity in GRB internal shocks, and the character of hydromagnetic turbulence in their environs. It is emphasized that diffusive shock acceleration theory generates no canonical spectrum at relativistic MHD discontinuities. This diversity is commensurate with the significant range of spectral indices discerned in prompt burst emission. Such system diagnostics are now being enhanced by the broad-band spectral coverage of bursts by the Fermi Gamma-Ray Space Telescope; while the Gamma-Ray Burst Monitor (GBM) provides key diagnostics on the lower energy portions of the particle population, the focus here is on constraints in the non-thermal, power-law regime of the particle distribution that are provided by the Large Area Telescope (LAT).
Variant Creutzfeldt-Jakob Disease and the Acquired and Transmissible Spongiform Encephalopathies

In 1995 a fatal epidemic of spongiform encephalopathy appeared in Great Britain. The new epidemic condition was clinically and pathologically similar to Creutzfeldt-Jakob disease (CJD), a rare sporadic encephalopathy, and was called "variant CJD" (vCJD). The vCJD epidemic was detected by active epidemiologic surveillance, which had been set up in response to a British epizootic of another new disease called "bovine spongiform encephalopathy" (BSE). Widespread cattle exposure to the BSE agent (a prion) had presumably been occurring in Britain since about 1982, when changes in the rendering process allowed infected material to contaminate cattle feed. Concern that the bovine disease might transmit to humans via beef consumption led to the active surveillance program. Tragically, BSE transmission to humans appears to have led to over 100 cases of vCJD. Millions of affected cattle were eventually slaughtered throughout Europe. Cattle are now routinely tested for BSE at 24-30 months of age, and affected herds are destroyed. These measures have exponentially reduced the BSE epizootic. Britain and other European countries that received contaminated beef or cattle feed nevertheless remain concerned about the combination of nearly universal past human exposure in Britain, variable exposure elsewhere, an unknown incubation period, vCJD case totals that continue to mount, and worst-case predictions that extend to many thousands of eventual human cases.
UHRF1 Plays a Role in Maintaining DNA Methylation in Mammalian Cells

Epigenetic inheritance in mammals relies in part on robust propagation of DNA methylation patterns throughout development. We show that the protein UHRF1 (ubiquitin-like, containing PHD and RING finger domains 1), also known as NP95 in mouse and ICBP90 in human, is required for maintaining DNA methylation. UHRF1 colocalizes with the maintenance DNA methyltransferase protein DNMT1 throughout S phase. UHRF1 appears to tether DNMT1 to chromatin through its direct interaction with DNMT1. Furthermore UHRF1 contains a methyl DNA binding domain, the SRA (SET and RING associated) domain, that shows strong preferential binding to hemimethylated CG sites, the physiological substrate for DNMT1. These data suggest that UHRF1 may help recruit DNMT1 to hemimethylated DNA to facilitate faithful maintenance of DNA methylation.
Modifiers of terminal deficiency-associated position effect variegation in Drosophila

Terminal deletions of a Drosophila minichromosome (Dp(1;f)1187) dramatically increase the position effect variegation (PEV) of a yellow(+) body-color gene located in cis. Such terminal deficiency-associated PEV (TDA-PEV) can be suppressed by the presence of a second minichromosome, a phenomenon termed "trans-suppression." We performed a screen for mutations that modify TDA-PEV and trans-suppression. Seventy suppressors and enhancers of TDA-PEV were identified, but no modifiers of trans-suppression were recovered. Secondary analyses of the effects of these mutations on different PEV types identified 10 mutations that modify only TDA-PEV and 6 mutations that modify TDA-PEV and only one other type of PEV. One mutation, a new allele of Su(var)3-9, affects all forms of PEV, including silencing associated with the insertion of a transgene into telomeric regions (TPE). This Su(var)3-9 allele is the first modifier of PEV to affect TPE and provides a unique link between different types of gene silencing in Drosophila. The remaining mutations affected multiple PEV types, indicating that general PEV modifiers impact TDA-PEV. Modifiers of TDA-PEV may identify proteins that play important roles in general heterochromatin biology, including proteins involved in telomere structure and function and the organization of chromosomes in the interphase nucleus.
Radiation effects at low electric fields in thermal, SIMOX, and bipolar-base oxides

We have performed thermally-stimulated-current (TSC) and capacitance-voltage measurements on 370-1080 nm thermal, SIMOX, and bipolar-base oxides as functions of bias, dose rate, and temperature during irradiation. Base oxides built in a development version of Analog Devices' RF25 process show much more interface-trap buildup than XFCB oxides. Both net-oxide-trap and interface-trap charge densities for RF25 capacitors are enhanced significantly during low-dose-rate or high-temperature irradiation at 0 V over high-rate, 25/spl deg/C exposures. TSC measurements show the increase in net-oxide-trap charge density is due to a decrease in trapped electron density with decreasing dose rate or increasing irradiation temperature (at least to 125/spl deg/C), and not by increased trapped hole density. Similar enhancement of net-oxide-trap and interface-trap charge density with decreasing dose rate is found for soft thermal oxides irradiated at 0 V, but not 5 V. These results strongly suggest that space charge effects associated with holes metastably trapped in the bulk of the oxide can cause the enhanced bipolar gain degradation seen at low dose rates and/or high temperatures in many technologies. No enhanced radiation-induced charge trapping is observed for low-dose-rate or high-temperature, 0 V irradiation of SIMOX capacitors. Implications for hardness assurance tests are discussed.
Facilitating conversations across time: Using simulations in living history training

This article describes the use of a simulation as a crucial part of a larger training program at a living history museum. The simulation provided an experiential, emotional base from which museum staff could re-envision their interactions with visitors and effect cultural and organizational change from within those interactions.
SnO2–Au hybrid nanoparticles as effective catalysts for oxygen electroreduction in alkaline media

Abstract SnO2 nanoparticles were synthesized by a facile electrochemical method based on anodic oxidation of a tin metal sheet. The resulting particles, with an average diameter of about 20 nm, were then loaded with varied amounts of HAuCl4, forming SnO2–Au(x) (x = 0, 0.095, 0.38, 0.76, 1.9, 3.0, and 3.8 at.%) hybrid nanoparticles after calcination at elevated temperatures (700 °C). X-ray diffraction (XRD) and transmission electron microscopic (TEM) measurements showed that the SnO2 particles exhibited high crystallinity with a rutile structure, and spherical Au nanoparticles were dispersed on the surface of the SnO2 support. Based on the TEM images and the width of the Au(2 0 0) XRD diffraction peak, the size of the Au nanoparticles was found to be between 15 and 35 nm in diameter and decrease with increasing loading of the original HAuCl4 precursor. The electrocatalytic activity of the resulting SnO2–Au(x) composite nanoparticles toward oxygen reduction reactions (ORR) was then evaluated by cyclic and rotating disk voltammetric measurements in alkaline solutions. It was found that the incorporation of gold nanoparticles led to apparent improvement of the catalytic activity of SnO2 nanoparticles. Moreover, the ORR electrocatalytic activity exhibited a strong dependence on the gold loading in the hybrid nanoparticles, and the most active catalyst was found with a gold loading of 1.9 at.%, based on the reduction current density and onset potential of ORR. Furthermore, at this gold loading, oxygen reduction was found to follow the efficient four-electron reaction pathway, whereas at other Au loadings, the number of electron transfer involved in oxygen reduction varied between 1 and 3. Additionally, Tafel analysis suggested that at low overpotentials, the first electron transfer might be the limiting step in oxygen reduction, whereas at high potentials, oxygen adsorption appeared to play the determining role at the SnO2–Au hybrid electrodes. These results indicate that the SnO2–Au composite nanoparticles might serve as effective catalysts for oxygen electroreduction in alkaline media.