cssi/SciSciGPT-SciSciNet huggingface dataset:
Comments on the kinetics and mechanism of yeast hexokinase action. Is the binding sequence of substrates to the enzyme ordered or random

The mechanism of action of yeast hexokinase was reinvestigated in light of a recent report in which it was suggested that substrates add to the enzyme in an ordered manner with the binding of glucose required to precede the binding of ATP. Initial velocity experiments were undertaken with AMP which is a competitive inhibitor for ATP, and with the product inhibitor glucose-6-phosphate. The results of these studies serve to exclude the ordered mechanism for yeast hexokinase from consideration. A discussion is presented in an attempt to show that yeast hexokinase may react in a random fashion with its substrates before forming a ternary complex of enzyme-ATP-glucose.
Teaching History Using the Short Story

(1993). Teaching History Using the Short Story. The Clearing House: A Journal of Educational Strategies, Issues and Ideas: Vol. 66, No. 5, pp. 305-306.
Dense 3D fractal tree structures as miniature end-loaded dipole antennas

As part of an effort to further improve modern communication system technology, researchers are studying different approaches for creating new and innovative antennas. One technique that has received a lot of recent attention involves combining aspects of fractal geometry with antenna design. This rapidly growing area of research is known as fractal antenna engineering. One particular class of antenna configurations is based on fractal trees. Fractal tree structures can be exploited in antenna designs to produce multiband characteristics or to achieve miniaturization. Dipole antennas that use fractal tree structures as end loads can achieve a resonant frequency lower than a standard dipole of comparable length. We discuss ways to improve antenna miniaturization techniques that employ fractal tree geometries as end loads by increasing the density of branches (i.e., by using trees with a higher fractal dimension).
The effects of relational and entity-relationship data models on query performance of end users

Abstract In database systems the end user interacts with the database at the external schema level. At this level the user sees only the logical structure of the database that is relevant to his/her work. Both the relational and the entity-relationship model have proponents arguing that one data model is superior to the other when used in the end user environment. However, a literature review indicated that these arguments have not been based on empirical results from a systematic inquiry. The study reported here examined this issue through a controlled experiment using query writing as the task. Our basic assumption was that if one data model was superior to the other, then the superiority of the model would be reflected in the user's query writing performance. In addition, this superiority would be demonstrated on both simple and complex tasks. Query writing performance was measured by three variables: number of syntax errors, number of semantic errors, and amount of time to complete queries. The results indicated that subjects using the relational model made fewer syntax errors, but required more time to complete a query. No significant differences in the number of semantic errors were found between the two data models. Based on these results, neither the relational nor the entity-relational data model was clearly superior when used as the interface between a database system and the end user. As expected, the more complex tasks caused more syntax and semantic errors, and required more time to complete.
Three-dimensional reconstruction and analysis of an entire solid oxide fuel cell by full-field transmission X-ray microscopy

Abstract An entire active region of an anode-supported solid oxide fuel cell was structurally analyzed by X-ray computed nano-tomography using full-field transmission X-ray microscopy (NANO-TXM). A total three-dimensional volume of ∼38,500 μm 3 was imaged, from which Ni–YSZ anode functional layer (∼3650 μm 3 ) and LSM–YSZ cathode functional layer (∼4100 μm 3 ) volumes were reconstructed. These were among the largest-volume electrode reconstructions ever reported, while at the same time exhibiting high spatial resolution of 50 nm. Comparison with electrode microstructures measured using other imaging methods demonstrates that the larger NANO-TXM-measured volumes provided significantly more accurate phase connectivity information. A microstructure-based electrochemical model prediction agreed well with the measured full-cell electrochemical data. The results suggest that low LSM connectivity and slow oxygen reduction reaction kinetics in the cathode were a major limitation to the overall cell performance.
Laboratory and field evaluation of broiler litter nitrogen mineralization

Abstract Two studies were conducted for this research. First, a laboratory incubation to quantify broiler litter N mineralization with the following treatments: two soil moisture regimes, constant at 60% water fill pore space (WFPS) and fluctuating (60–30% WFPS), three soil types, Brooksville silty clay loam, Ruston sandy loam from Mississippi, and Catlin silt loam from Illinois. Second, a field incubation study to quantify broiler litter N mineralization using similar soils and litter application rates as the laboratory incubation. Broiler litter was applied at an equivalent rate of 350 kg total N ha −1 for both studies except for control treatments. Subsamples were taken at different timing for both experiments for NO 3 –N and NH 4 –N determinations. In the laboratory experiment, soil moisture regimes had no significant impact on litter-derived inorganic N. Total litter-derived inorganic N across all treatments increased from 23 mg kg −1 at time 0, to 159 mg kg −1 at 93 d after litter application. Significant differences were observed among the soil types. Net litter-derived inorganic N was greater for Brooksville followed by Ruston and Catlin soils. For both studies and all soils, NH 4 –N content decreased while NO 3 –N content increased indicating a rapid nitrification of the mineralized litter N. Litter mineralization in the field study followed the same trend as the laboratory study but resulted in much lower net inorganic N, presumably due to environmental conditions such as precipitation and temperature, which may have resulted in more denitrification and immobilization of mineralized litter N. Litter-derived inorganic N from the field study was greater for Ruston than Brooksville. Due to no impact by soil moisture regimes, additional studies are warranted in order to develop predictive relationships to quantify broiler litter N availability.
Critical Properties of Argon

Abstract Measurements of P-V-T properties of argon in the critical region are reported. Isothermal compressibilities have been calculated from the data for liquid and vapor along the coexistence curve and for the gas above the critical temperature at the critical density. Densities of the liquid and vapor along the coexistence curve were measured, and the critical temperature, pressure and density of argon were redetermined. These data are compared with those of other workers; in addition critical indices which represent the manner in which these properties vary as one approaches the critical point were determined and compared with the predictions of several theoretical estimates of these quantities.
FAILURE TO FIND INTERCELLULAR PROTOPLASMIC CONTINUITY IN GRIFFITHSIA GLOBULIFERA

A method was devised for estimtaing the electrical resistance between the cytoplasm of adjacent cells of the red marine alga Griffithsia globulifera. A very high resistance was found, which argues strongly against the existence of protoplasmic continuity in this species.
Volumetric path following algorithms for linear programming

We consider the construction of small step path following algorithms using volumetric, and mixed volumetric-logarithmic, barriers. We establish quadratic convergence of a volumetric centering measure using pure Newton steps, enabling us to use relatively standard proof techniques for several subsequently needed results. Using a mixed volumetric-logarithmic barrier we obtain an O(n 1/4 m 1/4 L) iteration algorithm for linear programs withn variables andm inequality constraints, providing an alternative derivation for results first obtained by Vaidya and Atkinson. In addition, we show that the same iteration complexity can be attained while holding the work per iteration to O(n 2 m), as opposed to O(nm 2), operations, by avoiding use of the true Hessian of the volumetric barrier. Our analysis also provides a simplified proof of self-concordancy of the volumetric and mixed volumetric-logarithmic barriers, originally due to Nesterov and Nemirovskii.
Relationship between the subunits and "T" antigens of adenovirus type 12.

IN previous reports, we have described the separation of the group-specific (“A” antigen) and type-specific (“C” antigen) subunits of adenovirus 12 (ref. 1) and the “T” antigens2 of the highly oncogenic group A adenoviruses, and we have described, using indirect methods, the production of type-specific antigen in virus free hamster tumour cells induced by adenovirus type 12 (ref. 3).
Localization of A antigen sites on human erythrocyte ghosts.

DETAILED immunochemical knowledge of the heterosaccharide antigen determinants of the ABO blood groups has been gained from the study of glycoproteins of mammalian secretions 1–3. Less is known about the chemical composition and spatial distribution of the ABO antigen determinants in erythrocyte membranes. Because the erythrocytes envelope appears as a uniform unit membrane after positive staining4, standard electron microscopy has failed to relate the ABO antigen sites to any discrete membrane structure5.
Treatment strategies in childhood cancer.

Strategies for the treatment of childhood cancer have significantly evolved over time. Years ago, surgery was the only option for treating childhood cancer. Now, research has advanced treatment options to include multimodal therapy with chemotherapy, radiation, surgery and hematopoeitic stem cell transplantation. The focus on gene therapy research is also increasing. Pediatric nurses must have a thorough understanding of the treatment for childhood cancer so that as frontline healthcare providers, they give accurate information to patients and their families, deliver appropriate care, and assist with gathering data in support of ongoing research.
On the mixing time of the SIS Markov chain model for epidemic spread

In this paper we study the mixing time of the Markov chain model for epidemic spread over a given complex network. Each node is either susceptible (healthy) or infected at any given time. In this setting, the state of the system is one of 2n where n is the number of nodes. The Markov chain has a unique stationary distribution where all nodes are healthy with probability 1, and all initial probability distributions converge to the stationary distribution. In other words, epidemic eventually dies out after long enough time passes. Since the number of states, 2n, increases exponentially as the number of nodes, n, increases, it is difficult to analyze this model. We study the relationship between the Markov chain model and n-dimensional nonlinear dynamical system which approximates the evolution of the marginal probability that each node is infected. Our main result shows that this approximated model gives an upper bound on the true marginal probability as given by the Markov chain model. As an application of this, we show that when the origin, the all-healthy-state in the n-dimensional system, is globally stable then the Markov chain mixes fast, i.e. has an O(logn) mixing time. We farther show that the linear system obtained from linearizing around the origin also provides the same upper bound on the mixing time. For this, we give an alternative proof using linear programming.
GliP, a Multimodular Nonribosomal Peptide Synthetase in Aspergillus fumigatus, Makes the Diketopiperazine Scaffold of Gliotoxin†

The fungal metabolite gliotoxin has a redox-active disulfide bridge spanning carbons 3 and 6 of a diketopiperazine (DKP) scaffold. The proposed DKP synthetase, GliP, from Aspergillus fumigatus Af293, is a three module (A1-T1-C1-A2-T2-C2-T3) 236 kDa protein that can be overproduced in soluble form in Escherichia coli. Once primed on its three thiolation domains with phosphopantetheine prosthetic groups, GliP activates and tethers l-Phe on T1 and l-Ser on T2, before generating the l-Phe-l-Ser-S-T2 dipeptidyl enzyme intermediate. Release of the dipeptide as the cyclic DKP happens slowly both in wild-type GliP and in enzyme forms where C2 and T3 have been mutationally inactivated. The lack of a thioesterase domain in GliP may account both for the slow release and for the directed fate of intramolecular cyclization to create the DKP scaffold for subsequent elaboration to gliotoxin.
Effects of photoperiod and temperature on the rate of larval development, food conversion efficiency, and imaginal diapause in Leptinotarsa decemlineata.

Abstract Larvae of Leptinotarsa decemlineata developed faster and consumed less food under short-day (Sd, 12:12 h light:darkness) than under long-day (Ld, 18:6 h L:D) conditions. The average index of food conversion efficiency was 5.4 in the Ld (25 °C), and 7.2 and 11.9 (at 20 and 25 °C, respectively) in the Sd insects. Pupae were smaller under the Ld conditions due to a greater loss of biomass during the prepupal period that was nearly twice longer than in the Sd insects. Virgin Ld females laid eggs for 6 months and survived 13 months. The lack of oviposition, reduced food intake, and behavioural changes characterised diapause in the Sd adults. Application of 100 μg JH III to newly ecdysed adults was used to probe diapause intensity. At 25 °C, the treatment elicited oviposition most effectively in females that were just transferred from the Ld to the Sd conditions. A distinctly lower response occurred in insects that had been kept under Sd conditions since hatching; their transfer to Ld conditions at the time of treatment had little effect on JH sensitivity. JH application to Sd females reared at 20 °C caused enlargement of the germaria but no eggs were formed.
Teat Sinus Vacua at Different Milking Machine Vacua and Pulsator Ratios

Abstract Nine quarters of three cows were used in measuring maximum and residual teat sinus vacua after the end of milk flow at four milking vacuum levels and two pulsator ratios. The increase in maximum and residual teat sinus vacua was nearly linear from 250 to 400mm Hg milking vacuum. Between 400 and 500mm Hg milking vacuum, the increase in maximum teat sinus vacuum was nonlinear and increased rapidly. Congestion of the teat end and signs of discomfort to the cow were observed when the milking vacuum was 500mm Hg. From results of this study, it would appear that a stable milking vacuum above 400mm Hg should be avoided, because of excessive teat sinus vacuum and possible teat injury.
Layerwise fundamental solutions and three-dimensional model for layered media

A hybrid method is presented for the analysis of layers, plates, and multilayered systems consisting of isotropic and linear elastic materials. The problem is formulated for the general case of a multilayered system using a total potential energy formulation and employing the layerwise laminate theory of Reddy. The developed boundary integral equation model is two-dimensional, displacement based and assumes piecewise continuous distribution of the displacement components through the system's thickness. A one-dimensional finite element model is used for the analysis of the multilayered system through its thickness, and integral Fourier transforms are used to obtain the exact solution for the in-plane problem. Explicit expressions are obtained for the fundamental solution of a typical infinite layer (element), which can be applied in a two-dimensional boundary integral equation model to analyze layered structures. This model describes the three-dimensional displacement field at arbitrary points either in the domain of the layered medium or on its boundary. The proposed method provides a simple, efficient, and versatile model for a three-dimensional analysis of thick plates or multilayered systems.
Defect detection and signal processing for cast stainless steel

Abstract Reliable ultrasonic inspection of cast stainless steel components in the primary piping loop of pressurized water reactors (PWRs) has not been satisfactorily demonstrated to the US utilities. The inspection for flaws is difficult because strong reflections from the grain boundaries could mask the flaw signal response; in addition, the ultrasonic beam can be redirected by the ‘wave guide’ effect of the coarse grain structure. This paper discusses signal processing approaches that may be relevant to inspection of such materials. Specifically, spatial averaging—a proven technique for enhancing signals that exhibit spatial coherency—can be useful in enhancing signal-to-noise ratio (SNR) for flaws the length of which are larger than the average grain size. Several specimens of PWR main coolant piping, each a cast steel elbow welded to forged steel containing fatigue flaws, were examined with a field-usable ultrasonic imaging system and with a personal computer (PC) based data acquisition and imaging system, both developed under EPRI funding. In addition, inspection data were examined from a component in a PWR plant during a scheduled outage in 1987. The images produced before and after signal processing showed improvements in flaw detectability.
Homeostatic regulation of glutamate release in response to depolarization

Proper nervous system function requires a balance between excitation and inhibition. Systems of homeostasis may have evolved in neurons to help maintain or restore balance between excitation and inhibition, presumably because excessive excitation can cause dysfunction and cell death. This article reviews evidence for homeostatic mechanisms within the hippocampus that lead to differential regulation of glutamate and γ-aminobutyric acid release in response to conditions of excess depolarization. We recently found differential effects on glutamate release at the level of action potential coupling to transmitter release, vesicular release probability, and vesicle availability. Such differential regulation may help to prevent excitotoxicity and runaway excitation.
Coherence in electronically excited dimers. The observation of coherent dimers and its relationship to coherent excitons

The coherent nature of molecular excited dimers in their triplet states is unequivocally established by a series of low temperature optically detected magnetic resonance experiments in zero field. The results clearly establish that a minimum coherence time for the dimer ψ(+) state in 1,2,4,5-tetrachlorobenzene (≈ 1.7 K) is longer than 5 × 10^(−7) s while the exchange time in these systems is approximately 16 × 10^(−12) s. This implies that the coherence persists for a time approximately 10^5 times that associated with the stochastic limit. The coherence time could, however, be even longer. Moreover, these new results clearly demonstrate that there is a direct and quantitative relationship between coherent properties of dimers and the coherent properties of triplet Frenkel excitons.
The Effect of Gingival Inflammation on Nocturnal Masseter Muscle Activity

The relationship of gingival inflammation to nocturnal muscle activity was studied, using the sulcus bleeding index and nocturnal EMG recordings.
Difficult Dialogues: Enhancing Discussions about Diversity.

e have a growing education al priority to address social and cultural diversity and various forms of oppression (e.g., racism, sexism, heterosexism, classism). Increas ingly, classes include material about a wider range of people's lives and direct discussions about the politics of differ ence and inequality. In most cases, facul ty members are intentionally trying to create a more inclusive curriculum; at other times, students are raising these issues, whether or not this was the teacher's agenda. Even though they often have good intentions and the desire to deal with mul ticultural issues in their classes, many teachers admit uncertainty about how to actually do it. There are fears and anxiety about how to approach and manage the discussion. These emotional issues may challenge deeply held beliefs and atti tudes. Although there are growing num bers of resources to address the content? activities, syllabi, books, and videos, few resources discuss the process (see Fisher
Historical perspectives on US business organisations, strategy, and higher education institutions

Strategy has guided business management for years but has not fully taken root in colleges and universities. This paper examines the evolution of US business and postsecondary institutions to explain the discrepancy in strategy adoption. While firms have developed to maintain internal effectiveness and to meet external needs, US colleges and universities have focused more consistently on societal needs. The final section of the paper posits Operational Effectiveness (OE) (Porter, 1996) as a theoretical starting point for practice-oriented research on using strategy in higher education.
Residual oil fly ash exposure enhances allergic sensitization to house dust mite

Epidemiological studies have shown an association between elevated levels of particulate matter air pollution and increased morbidity and hospital visits in asthmatics. Residual oil fly ash (ROFA) is a primary combustion particle containing sulfate and metals such as vanadium, nickel, and iron. In this study the effect of ROFA on sensitization to house dust mite (HDM) was examined in a Brown Norway rat model of pulmonary allergy. Rats were instilled via the trachea with 200 or 1000 μg ROFA 3 days prior to local sensitization with 10 μg HDM and were challenged with 10 μg HDM 14 days later. Immunological endpoints were examined at 2, 7, and 14 days after sensitization and at 2 and 7 days after challenge (16 and 21 days post-sensitization, respectively). Antigen-specific immunoglobulin E and associated immediate bronchoconstriction responses to antigen challenge were increased in the ROFA-treated groups compared with the HDM control group. Lymphocyte proliferation to antigen was enhanced at Days 7 and 21 in the bronchial lymphocytes of ROFA-treated groups. Bronchoalveolar lavage fluid (BALF) eosinophil numbers and lactate dehydrogenase were significantly increased in the 1000 μg ROFA group at Days 2 and 16, BALF total proteins were elevated at Days 2 and 7 in both ROFA-treated groups, and BALF interleukin (IL)-10 was elevated in the 1000 μg ROFA group at Day 2. These results suggest that ROFA has an adjuvant effect on sensitization to HDM.
A counterexample to a martingale characterization of a Wiener process

Abstract We show that a Wiener process is not characterized by a martingale and a reverse martingale property of some linear and quadratic transformations of the process.
Hydrogen bonding in salicylaldehyde: A molecular orbital study

Abstract Calculations were done at the 6–31G level on hydrogen-bonded salicylaldehyde and the rotamer in which the OH group is rotated 180° about the CO bond axis, assuming that the structures are planar but otherwise with full geometry optimization. The parameters for the hydrogen bridge, the six-membered hydrogen-bonded ring, and the changes in converting the rotamer into the hydrogen-bonded structure are compared with values obtained for the aliphatic analog, β-hydroxyacrolein, calculated using the 4–31G basis set. The concomitant changes in bond length in the benzene ring are similar in magnitude, showing that the perturbation of the OH group spreads throughout the entire molecule. Mulliken population analysis indicates that the changes in total atomic charge and overlap populations are due primarily to π-electron and σ-electron effects, respectively. The hydrogen bond energy is evaluated using this rotamer as the reference state, the rotamer in which the HCO group is rotated 180° about the CC bond axis, and also benzene, benzaldehyde and phenol as a composite reference state. The procedures by which intramolecular hydrogen bond energies are derived, in part or entirely, from experimental measurements are compared and contrasted with the methodology involved in molecular orbital calculations.
An electrochemical and microbiological study of the formic acid-formic dehydrogenlyase system

Enzyme activity and substrate concentration effects on hydrogen production from formic acid/ formic dehydrogenlyase system
Synthesis and Characterization of Poly(2,6-triptycene)

We report the syntheses of two monomers, 2,6-dibromotriptycene and 2,6-diiodotriptycene, and their applications in the homopolymerization via a nickel(0)-mediated Yamamoto-type polycondensation polymerization, leading to a novel aromatic polymer—poly(2,6-triptycene). This new polymer was characterized by 1H and 13C NMR spectroscopy, which exhibited an excellent match with the NMR spectra of the model compound, 2,2′-bitriptycene. In addition, the polymer was found to be highly soluble in common organic solvents, although it does not contain any flexible side chains. This good solubility was attributed to its high content of triptycene units, whose rigid three-dimensional structure was proposed to prevent dense packing of polymer chains. A highly transparent film could be obtained by spin-casting a chloroform solution. This polymer also demonstrated good thermal stability.
Effects of long-acting beta adrenergic agonists on vocal fold ion transport.

Objectives: Inhaled medications prescribed for the hypersensitive airway typically combine corticosteroids and long-acting β2 adrenergic agonists (LABAs). The phonatory side effects of these combination treatments are widely recognized. However, there is limited understanding of the physiological changes induced by these medications that underlie the phonatory side effects. The objective of this study was to investigate the distinct effects of corticosteroids and LABAs on vocal fold mucosal physiology. Understanding the physiological changes to the vocal folds after corticosteroid and LABA treatments is necessary to prevent the prevalent vocal decrement associated with these medications. Study Design: Experimental in vitro design with treatment and control groups. Methods: Native porcine vocal fold mucosae (N = 38) were exposed to corticosteroid or LABA treatments. Ion transport was measured continuously at baseline and after treatment. To quantify the nature of ion transport, vocal folds were also treated with chloride and sodium channel inhibitors. Results: Corticosteroid treatment did not alter ion transport. Conversely, exposure to LABAs significantly increased ion transport. This increase in ion transport was transient, observed immediately after treatment in all tissue and associated with increased chloride secretion. Conclusions: The distinct effects of corticosteroids and LABAs on vocal fold physiology have not been examined to date. This study demonstrates that short-term treatment with LABAs, but not corticosteroids, significantly increases ion transport. These findings suggest that one underlying physiological mechanism for phonatory changes associated with inhaled treatments may be related to acute alterations in vocal fold ion transport and surface hydration. Laryngoscope, 2009
Serial-pattern-learning processes dissociated by trimethyltin exposure in rats

Trimethyltin (TMT) is a neurotoxic organometal which produces a variety of learning and memory impairments in laboratory animals and humans, including impairments of avoidance learning, maze learning, and problem solving. Two studies investigated the effects of TMT exposure on serial-pattern learning in rats. Rats in both experiments were intubated once with either 0 or 7.0 mg/kg TMT 1 week prior to the pattern-learning procedure. Rats learned serial patterns composed of various quantities of brain-stimulation reward (BSR) pulses; they received BSR quantities in a predetermined order for leverpresses in a discrete-trial operant task. In Experiment 1, all rats received two serial patterns (20-10-0 vs. 1-29-0 pulses of BSR) that alternated within each daily session of 100 patterns. In Experiment 2, all rats received two serial patterns (18-10-6-3-1-0 vs. 18-1-3-6-10-0 pulses of BSR) that alternated within each daily session. In Experiment 1, TMT-exposed rats learned both their patterns more slowly than did controls. In Experiment 2, TMT-exposed rats learned the formally simple 18-10-6-3-1-0 pattern of BSR quantities faster than did controls, but were significantly slower than controls in learning the formally more complex 18-1-3-6-10-0 pattern. In both experiments, however, TMT exposure did not affect either the reinforcing properties of BSR or rats’ asymptotic performance. These results support the notion that TMT exposure impaired some aspects of the rote processes involved in serial-pattern learning in rats, yet spared the rats’ ability to encode some representation of the formal rule-based structure of the pattern. The results thus suggest that the processes involved in learning simple versus complex serial patterns may be mediated by different systems in the brain.
Specific degradation of subendothelial matrix proteoglycans by brain-metastatic melanoma and brain endothelial cell heparanases.

One of the many features of the malignant phenotype, in vitro and in vivo, is elevated heparanase production and activity. Using in vitro model systems, we examined the capacity of murine (B16B15b) and human (70W) brain-metastatic melanoma cells to degrade the subendothelial matrix produced by endothelial cell monolayer cultures. B16B15b and 70W melanoma cells solubilized sulfated matrix proteoglycans at levels significantly higher than their parental lines (B16F1, MeWo). Sulfated matrix proteoglycans were rich in heparan sulfate (HSPGs), with minor amounts of chondroitin and dermatan sulfates. When matrix HSPGs were treated with pronase and alkaline borohydride to cleave the core proteins, the resulting glycosaminoglycan chains (GAGs) had an estimated Mr of ∼2.7 × 104 Da, with a minor subpopulation possessing an Mr of ∼4.5 × 104 Da. After their incubation with brain-metastatic melanoma cells, new HS fragments with lower Mr estimated at ∼9 × 103 Da were detected. This confirms action in these cells of heparanase, which is capable of cleaving GAGs at specific intrachain sites and releasing fragments of a relatively high Mr. The pattern of HSPG degradation by brain-metastatic melanoma cells differed from that of less metastatic parental cells or cells metastatic to organs other than the brain. Moreover, supraadditive levels of heparanase activity were found when brain endothelial cells were coincubated with brain-metastatic melanoma cells in equicellular amounts. Cooperative interactions between heparanases from tumor and endothelial sources in the invasion process are suggested and their potential mechanisms discussed. J. Cell. Physiol. 172:334–342, 1997. © 1997 Wiley-Liss, Inc.
Anergy or cell death induced by low physiological temperature in mitogen-stimulated human T lymphocytes

Abstract 1. 1. Human T cell proliferation is suppressed at 27°C, and is both diminished and delayed at 32°C. 2. 2. Temperature shift-up and viability assays indicated that concanavalin A stimulation at 27°C induced cell death in contrast to a transient unresponsiveness (anergy) induced by monoclonal anti-CD3 antibody (αCD3) and the superantigen, staphylococcal exterotoxin B. 3. 3. Phytohemagglutinin also induced cell death at 27°C; however, some cells remained viable and proliferation occurred when such cultures were subsequently moved to 37°C. 4. 4. Low temperature suppression of T cell activation was not overcome by a mixture of phorbol ester and calcium ionophore indicating a probable block post-protein kinase C activation. This was confirmed in temperature shift-down assays where incubation for 18–24 h at 37°C was required to bypass the block at 27°C. 5. 5. With the exception of αCD3, stimulation at 27°C with the mitogens resulted in interleukin-2 secretion, indicating that the low temperature block(s) is a relatively late event in cell activation.
Molecular genetics of optic glioma: lessons learned from neurofibromatosis-1 genetically engineered mice

Neurofibromatosis type 1 is an inherited cancer predisposition syndrome in which 15–20% of children develop optic gliomas. Most of these tumors form along the optic nerve and chiasm, where they can cause decreased visual function and endocrine dysfunction. Advances in mouse modeling of this disease have created tractable models to study the role of specific genetic alterations, deregulated intracellular signaling pathways and non-neoplastic cells in the development of optic gliomas. These small-animal models have been used as platforms to discover new targets for drug design and to evaluate the efficacy of these potential anticancer treatments prior to clinical trials in children with optic glioma.
Observations and Numerical Simulations of Precipitation Development in Seeded Clouds over the Sierra Nevada

Abstract The evolution of precipitation in seeded wintertime orographically induced convective and stratiform clouds with embedded convection were studied using in situ observations and particle growth and trajectory models. The particle growth model of Heymsfield embedded in a kinematic flow field representative of the Sierra barrier was used to study the ice particle growth by diffusion, accretion and subsequent fall trajectories. The particles observed by the aircraft were classified into habits. The growth of observed particles were compared with the model predicted evolution. Using the aggregation model of Heymsfield, the observation of formation of aggregates in 1 mm) form in 4–8 minutes after seeding a convective cloud. (ii) Riming is important close to the barrier in a stratiform cloud when large cloud droplets and liquid water up to 0.3 g m−3 are present. (iii) Diffusional growth is extremely important for temperatur...
A review of Trachusoides Michener and Griswold (Hymenoptera: Megachilidae).

The rare genus Trachusoides , previously known only from a single species inhabiting the Western Ghats of India, is reviewed. Trachusoides elsieae , new species, is described from Laos, additional records for T. simplex are documented, and a key to separate the species is provided.
Novel drugs for older patients with acute myeloid leukemia

Acute myeloid leukemia (AML) is the second most common form of leukemia and the most frequent cause of leukemia-related deaths in the United States. The incidence of AML increases with advancing age and the prognosis for patients with AML worsens substantially with increasing age. Many older patients are ineligible for intensive treatment and require other therapeutic approaches to optimize clinical outcome. To address this treatment gap, novel agents with varying mechanisms of action targeting different cellular processes are currently in development. Hypomethylating agents (azacitidine, decitabine, SGI-110), histone deacetylase inhibitors (vorinostat, pracinostat, panobinostat), FMS-like tyrosine kinase receptor-3 inhibitors (quizartinib, sorafenib, midostaurin, crenolanib), cytotoxic agents (clofarabine, sapacitabine, vosaroxin), cell cycle inhibitors (barasertib, volasertib, rigosertib) and monoclonal antibodies (gentuzumab ozogamicin, lintuzumab-Ac225) represent some of these promising new treatments. This review provides an overview of novel agents that have either completed or are currently in ongoing phase III trials in patients with previously untreated AML for whom intensive treatment is not an option. Other potential drugs in earlier stages of development will also be addressed in this review.
Regulation of phenylethanolamine N-methyl transferase.

Phenylethanolamine N-methyl transferase (PNMT) catalyzes the methylation of norepinephrine, forming epinephrine in the adrenal medulla. In vitro, PNMT accepts a variety of phenylethanolamines and phenylethylenediamines as substrates. It is inhibited by phenethylamines and other compounds structurally similar to its substrates, as well as by agents that bind to sulfhydryl groups. Specific inhibitors of PNMT may be useful pharmacologic tools and potentially drugs. A group of benzylamines, including 2,3-dichloro-α-methylbenzylamine, are among the most potent inhibitors presently known. In vivo, maintenance of PNMT levels in the adrenal medulla is dependent upon an adequate supply of glucocorticoids from the adrenal cortex. Neural input to the medulla may also influence the enzyme level. The possibility that product inhibition may influence PNMT activity in vivo requires further study.
An Occultation by Saturn's Rings on 1991 October 2-3 October 2-3 Observed with the Hubble Space Telescope

An occultation of the star GSC 6323-01396 (V = 11.9) by Saturn's rings was observed with the High-Speed Photometer on the Hubble Space Telescope (HST) on 1991 October 2-3. This occultation occurred when Saturn was near a stationary point, so the apparent motion of Saturn relative to the star was dominated by the HST orbital motion (8 km/s). Data were recorded simultaneously at effective wavelengths of 3200 and 7500 A, with an integration time of 0.15 s. Fifteen segments of occultation data, totaling 6.8 h, were recorded in 13 successive orbits during the 20.0 h interval from UTC 1991 October 2, 19:35 until UTC 1991 October 3, 15:35. Occultations by 43 different features throughout the classical rings were unambiguously identified in the light curve, with a second occultation by 24 of them occurring due to spacecraft orbital parallax during this extremely slow event. Occultation times for features currently presumed circular were measured and employed in a geometrical model for the rings. This model, relating the observed occultation times to feature radii and longitudes, is presented here and is used in a least-squares fit for the pole direction and radius scale of Saturn's ring system.
Grade repetition in Honduran primary schools

Abstract This paper looks at several dimensions of the grade failure issue in Honduras using a unique data set compiled by the UMCE evaluation project in 1998 and 1999. The analytical framework incorporates econometric analysis of standardized tests and teacher pass/fail decisions for roughly 13,000 second and fourth grade students. The results show that first time grade repetition, as well as repeating previous grades, is associated with lower marginal achievement on the UMCE exams, although the same is not true for students who are repeating the second or third time. The strongest predictor of grade failure is previous repetition, despite the inclusion of controls for achievement and attendance. The implications of this apparently strong stigma effect associated with grade repetition are discussed, as well as other policy issues related to grade repetition in developing countries.
Contemporary Ghost Stories: Cyberspace in Fiction for Children and Young Adults.

This essay identifies a genre of popular fiction for children and young adults, prevalent in the 1990s and continuing into the early twenty-first century, that incorporates computers and the internet, e-mails and chat rooms, into its plots. However, along with a focus on technology, this fiction frequently features the supernatural. So, too, ghosts have been recurring images in popular culture surrounding past emergent communications technologies. I argue that the figure of the ghost in these novels about cyberspace dramatizes the tension between the liberating possibilities of disembodiment and the desire for embodied relationships. Despite the presence of dystopian elements, this fiction remains optimistic overall about the potential of technology to connect individuals in positive ways and to create communities modeled on tolerance and inclusion.
Buckling characterization of gate all around silicon nanowires

Imaging of suspended silicon nanonwires (SiNW) by SEM reveals that some of the SiNW are buckled. Buckling can impact device performance and it is therefore important to characterize this phenomenon. Measuring the buckling of suspended silicon nanowires (SiNW) poses significant challenges: (1) Small dimensions - SiNW are made with diameters ranging from about 3 to 10 nm and the buckling is of a similar scale. (2) Accurate height measurements – buckling is a three dimensional phenomena. To meet these challenges a new height map reconstruction technique was introduced, using the CDSEM side detectors signal. Measuring pixel by pixel position in X, Y and Z (height) dimensions, we can obtain the buckling vector gradient along the wire in three dimensions. In this paper we present: (1) A description of the height map reconstruction technique used. (2) Three dimensional characterization of SiNW: (a) SiNW buckling measurements (b) Characterization of buckling as a function of the SiNW length and width.
The Luminosity Function of Nearby Galaxy Clusters. I. A Catalog of Galaxies Within the Central 0.83 Square Degrees of the Centaurus Cluster

We present a catalog of all galaxies with V ? 22.0 and Riso > 3'' within a 0.83 deg2 region centered on the Centaurus Cluster (Abell 3526) at ? = 12h48m, ? = -41?18'. V-band total magnitudes along with other photometric parameters were obtained from the detection programs FOCAS and SExtractor and also from fitting curve-of-growth S?rsic functions to the galaxy profiles. Central surface brightnesses, half-light radii, ellipticity, and position angles are presented, along with (B - V) aperture colors where B-band data were obtained. This work is part of a larger program to study the cluster-to-cluster variation in the faint end of the LF based on the study of eight clusters, including Centaurus. We discuss our data reduction methods in this paper. More detailed analyses and science results will be presented in subsequent papers.
VLSI implementation of a 2-D DCT in a compiler

A 100 MHz realization of a 2D DCT (discrete cosine transform) in a compiler is presented. An optimal nibble-serial distributed arithmetic architecture is used for an efficient direct implementation of the DCT. The compiler, which is based on BiCMOS gate array technology and functional module generation technology, is used to support a rapid prototyping environment. An 8*8 inverse 2D DCT example in a 0.8 mu m BiCMOS gate array is given to illustrate the performance and flexibility of this approach. The design flow and a proposed development system, the Signal Analysis Workstation (SAW), are shown for customized system integrations. >
C–S–H/polyaniline nanocomposites prepared by in situ polymerization

Synthesis and characterization of a new cement-based polymer nanocomposite is reported. Calcium silicate hydrate (C–S–H) was prepared in the presence of aniline monomer followed by in situ polymerization to increase the degree of interaction between inorganic and organic phases. Two stoichiometrically different C–S–H systems were used. The properties of the C–S–H/polyaniline materials were studied using several analytical techniques including SEM, XRD, TGA, 29Si MAS NMR and FTIR. It is suggested that the in situ polymerization method can effectively be employed for producing a C–S–H/Polymer nanocomposite. The extent of molecular interaction with the polymer depends on the chemical composition of the C–S–H. Production of a new range of polymer-modified cement-based systems having improved environmental stability and mechanical performance is promising.
Burroughs Algol at Stanford University, 1960-1963

The decade between 1955 and 1965 brought a revolution to academic computing, both technologically and socially. As core memory replaced electrostatic memory while transistors replaced vacuum tubes, computers advanced from flakey and difficult-to-maintain devices to reliable appliances. At the same time (and partially as a consequence), the academic use of computing expanded rapidly, computing centers became increasingly essential facilities on every campus, and computer science began to gain acceptance as a legitimate academic discipline. This Anecdote recounts the author's experience during this dramatic shift in academic computing at Stanford University during the period between 1960 and 1963. It also records a chapter in the early development of compiler design and programming technology.
Moist dynamics and orographic precipitation

Uniformly stratified moist flow over a Gaussian-shaped circular mountain is investigated using anonhydrostatic mesoscale model. The focus is the interaction between flow stagnation and orographicprecipitation. Two closely related issues are addressed: the effect of condensation and precipitation onmountain flow stagnation, and the influence of flow blocking and latent heat on upslope precipitation. Itis demonstrated that latent heat release and precipitation can significantly delay the onset of mountainflow stagnation. The dynamical and thermodynamical nature of this modification can be qualitativelyunderstood using the moist stability concept. However, due to the vertical variation of the moist stability,it is not possible to define a single nondimensional mountain height to describe the general nonlinearityof moist orographic flow. The effect of flow blocking and splitting on the intensity and distribution oforographic precipitation is found to be significant. For lowmountains, the upslope ascent dominates andthe precipitation intensity is roughly proportional to the mountain height and windspeed as predicted byboth a slab model and the mesoscale model. For high mountains, this relationship breaks down becausethe mountain lift effect is reduced as the low level moist flow passes around the peak. An arc-shapedprecipitation band forms further upstream of the peak where the terrain slope is gentle, associatedwith the secondary circulation forced by the upstream flow blocking/reversal. The removal of latentheat processes leads to reduced upslope lift and enhanced windward blocking, thereby reducing themaximum precipitation rates and increasing the precipitation area. DOI: 10.1034/j.1600-0870.2003.00025.x
The North Carolina Geospatial Data Archiving Project: Challenges and Initial Outcomes

The North Carolina Geospatial Data Archiving Project (NCGDAP) is a partnership of the North Carolina (NC) State University Libraries and the NC Center for Geographic Information & Analysis focused on preservation of state and local geospatial data. This project, executed under an agreement with the Library of Congress as part of the National Digital Information Infrastructure and Preservation Program (NDIIPP), is helping to inform development of a national digital preservation infrastructure through a learning-by-doing approach focused on identifying, acquiring, and preserving content within the context of the NC OneMap initiative and its framework of partnerships with state, local, and federal agencies. Although the collection-building aspect of this project is focused solely on the state of North Carolina, the project has served as a demonstration that informs data archiving and time series development more generally. The article discusses how the project has responded to key challenges, including ident...
Children of Reform: The Impact of High-Stakes Education Reform on Preservice Teachers.

High-stakes standards-based accountability reforms are changing teacher education. A key set of participants in this process who have been affected by these reforms are the teacher candidates. Many were educated almost entirely in high-stakes education systems. Yet, little is known about how their experiences as students affect their conceptions of teaching and learning or how their teacher education programs alter these perceptions. This article presents findings from a case study that explored these critical issues. It reveals that these candidates entered their teacher education program with a complex understanding of the impact of these reforms on teaching and learning. These findings also illuminate how these prospective teachers’ coursework and field experiences affected their conceptions of these constructs. This article ends by offering suggestions to teacher educators on how to incorporate these candidates’ skills and knowledge into their programs so that they can assist their candidates in becom...