cssi/SciSciGPT-SciSciNet huggingface dataset:
Accuracy of a damage-based reconstruction method in NHTSA side crash tests.

Objective: Delta-V (ΔV), the magnitude of the velocity change experienced by a vehicle during a crash, is widely used as a predictor of injury risk. The National Automotive Sampling System/Crashworthiness Data System (NASS-CDS) uses the WinSMASH computer code to reconstruct ΔV based on postcrash vehicle deformation. WinSMASH, a direct descendant of CRASH3, first uses vehicle damage to estimate absorbed energy and then applies momentum conservation to estimate ΔV. This study aims to determine the accuracy of WinSMASH ΔV reconstructions for NHTSA side crash tests. Methods: This study is based upon 168 dynamic side impact tests conducted by the National Highway Traffic Safety Administration (NHTSA). For each crash test the actual ΔV for the struck vehicle was first determined from test instrumentation. WinSMASH was then used to reconstruct the struck vehicle ΔV for each test. WinSMASH-reconstructed ΔVs were compared to measured ΔVs for each test to assess reconstruction accuracy. Results: WinSMASH predicts Δ...
Vibrationally mediated photodissociation of CH3Cl: the v=3 and 4 CH stretch overtone levels

Abstract The photodissociation of jet-cooled vibrationally excited CH 3 Cl near 235 nm has been investigated by detection of the Cl ( 2 P 3/2 ) and Cl ( 2 P 1/2 ) photofragments through resonance enhanced multiphoton ionization (REMPI) in a time-of-flight mass spectrometer. Vibrationally excited molecules with three or four quanta of CH stretch excitation were prepared by irradiation with tunable near infrared (NIR) laser radiation, and a single UV laser beam was used for both photolysis and fragment detection. The action spectra of the photofragments were much more highly resolved than the room-temperature photoacoustic (PA) spectrum. The differing intensities of vibrational bands in the PA and action spectra are discussed.
Dynamic programming for pennies a day

An elegant solution to a fun problem is presented as a way to introduce dynamic programming. This problem, the Nine Tails, can be used as an introductory supplement to the traditional examples offered in many textbooks which cover dynamic programming.
Alterations in neuronal gene expression profiles in response to experimental demyelination and axonal transection

The main pathological features of multiple sclerosis, demyelination and axonal transection, are considered to cause reversible and irreversible neurological deficits, respectively. This study aimed to separately analyze the effects of these pathological hallmarks on neuronal gene expression in experimental paradigms. The pontocerebellar pathway was targeted with either lysolecithin-induced chemical demyelination or a complete pathway transection (axonal transection) in rats. Transcriptional changes in the pontocerebellar neurons were investigated with microarrays at days 4, 10 and 37 post-intervention, which was confirmed by immunohistochemistry on protein level. A common as well as unique set of injury-response genes was identified. The increased expression of activating transcription factor 3 (Atf3) and thyrotropin-releasing hormone (Trh) in both injury paradigms was validated by immunohistochemistry. The expression of Atf3 in a patient with Marburg’s variant of multiple sclerosis was also detected, als...
The segmented nature of the Chilean seismic zone

Abstract The better located earthquakes from the Earthquake Data File of NOAA during the period from 1967 to December 1971 define a seismic zone dipping eastward below Chile with a thickness of 20–70 km. Vertical sections were used to examine the morphology of the zone. The orientation of the vertical sections and the limits of the area projected onto the sections were chosen to produce plots of the seismic zone showing the least thickness and steepest dip. These conditions should be characteristic of sections which are perpendicular to the seismic zone. Seven segments that differ in strike and dip were found. The segments range in dip from 20° to 30° and have lengths of 300–850 km. There are offsets of the seismic zone between adjacent segments of up to 50 km and changes in strike of up to 30°. There are similar offsets in the historically active volcanic chain. The breaks in the deep seismic zone correspond to abrupt changes in topography and tectonic structures. The margins of great earthquake aftershock zones correspond well with the segment boundaries proposed here.
Existence of a nonarithmetic lattice in SU(2,1).

Abstract The proof of the well-known conjecture that lattices in groups of R-rank greater than 1 are arithmetic has raised speculation about the existence of nonarithmetic lattices in the R-rank 1 group SU(n,1), n > 1. This paper presents an example of such a lattice Γ1. Γ1 consists of the intersection with SU(2,1) of a group Γ generated by three complex reflections of order 5. The quotient SU(2,1)/Γ1 is compact.
The abundance of Kaluza-Klein dark matter with coannihilation

In universal extra dimension models, the lightest Kaluza-Klein (KK) particle is generically the first KK excitation of the photon and can be stable, serving as particle dark matter. We calculate the thermal relic abundance of the KK photon for a general mass spectrum of KK excitations including full coannihilation effects with all (level-one) KK excitations. We find that including coannihilation can significantly change the relic abundance when the coannihilating particles are within about 20% of the mass of the KK photon. Matching the relic abundance with cosmological data, we find the mass range of the KK photon is much wider than previously found, up to about 2 TeV if the masses of the strongly interacting level-one KK particles are within 5% of the mass of the KK photon. We also find cases where several coannihilation channels compete (constructively and destructively) with one another. The lower bound on the KK photon mass, about 540 GeV when just right-handed KK leptons coannihilate with the KK photon, relaxes upward by several hundred GeV when coannihilation with electroweak KK gauge bosons of the same mass is included.
Anthropology as a Sustainability Science

: [sustainability, climate change, environment, applied anthropology, NCARE, Center for Environmental Science, sustainable development]
Toxicant Adsorption on Activated Charcoal: Is the Fraction Adsorbed a Unique Function of the Charcoal: Adsorbate Ratio?

In several recent studies the adsorption of toxicants on activated charcoal has been reported graphically in the form of plots presenting the fraction of toxicant unadsorbed at equilibrium (F) as a unique function of the ratio (R) of the amount of activated charcoal to that of total toxicant. Derivation of the mathematical relationship between these two variables from either the Freundlich or Langmuir isotherms reveals F is not uniquely defined by R, unless the amount of activated charcoal, the equilibrium concentration of the toxicant, or its initial concentration is kept constant. For two agents known to adhere to the Freundlich isotherm, paraldehyde and metaldehyde, a good agreement was obtained between the F and R values predicted by the derived equations and those observed experimentally. The usefulness of F versus R plots is discussed.
Indole Cytosolic Phospholipase A2 α Inhibitors: Discovery and in Vitro and in Vivo Characterization of 4-{3-[5-Chloro-2-(2-{[(3,4-dichlorobenzyl)sulfonyl]amino}ethyl)-1-(diphenylmethyl)-1H-indol-3-yl]propyl}benzoic Acid, Efipladib

The optimization of a class of indole cPLA2α inhibitors is described herein. The importance of the substituent at C3 and the substitution pattern of the phenylmethane sulfonamide region are highlighted. Optimization of these regions led to the discovery of 111 (efipladib) and 121 (WAY-196025), which are shown to be potent, selective inhibitors of cPLA2α in a variety of isolated enzyme assays, cell based assays, and rat and human whole blood assays. The binding of these compounds has been further examined using isothermal titration calorimetry. Finally, these compounds have shown efficacy when dosed orally in multiple acute and chronic prostaglandin and leukotriene dependent in vivo models.
LCAO methods in the Xα formalism: A comparison of results for the F2 molecule

The LCAO-Xα method of Dunlap is compared to other recently developed methods using the Xα local density exchange potential for the F2 system. The results indicate that the LCAO-Xα method is capable of finding results close to the Xα limit.
Single-shot coronary arteriography

A single-shot procedure for coronary arteriography has provided effective visualization in dogs. An electronic circuit controls injection of a small bolus of contrast medium over two or three heart cycles by the retrograde approach, and automatically triggers the X-ray in late diastole, when opacification is complete.
Continuous measurement of material damping during fatigue tests

An experimental procedure for continuously measuring strain level, temperature, and energy-dissipation rate during resonant fatigue tests is described. The technique is based on a previous method for measuring loss factor (Ref. 3) using base-excited cantilever-beam specimens vibrating at resonance. The amplitude and frequency dependence of loss factor is therefore included directly in the measurement. For beams vibrating in vacuum, energy-dissipation rate and temperature measurements provide a basis for irreversible thermodynamic analysis of fatigue. This procedure provides a continuous measurement of energy-dissipation rate during fatigue-crack nucleation, and is the basis for experimental study of the hypothesis that the entropy gained during fatigue failure is a material constant.
Symptomatology of adductor spasmodic dysphonia: A physiologic model*

Summary Vocal symptomatology of adductor spasmodic dysphonia (SD) is reviewed critically from historical, epidemiologic, and clinical perspectives. A model of symptomatology of this disorder based on a large patient population, and clinical and physiologic observations is advanced. The model incorporates crucial symptomatic and asymptomatic phonatory and nonphonatory physiologic parameters of laryngeal behavior in these patients. These parameters include vocal fold contact area, vocal fold collision force, glottic compression, and subglottic air pressure. Inappropriate efferent discharges from brain-stem basal ganglia are hypothesized as causing overadduction of the vocal folds in phonation, generating the basic and fundamental vocal symptom of adductor SD—strained, strangled, overpressured voice quality. Cortical loops are implicated as accountable for compensatory vocal behavior, not as the primary site of the disorder. Symptom occurrence, variability, magnitude, effects, and failure of treatment approaches, as well as recurrence of symptoms after ablative or invasive procedures, are explained by this model. The model also predicts that symptomatology of adductor spasmodic dysphonia is unique to this disorder and that symptoms are phonotopically organized. The minimal diagnostic battery based on the model is presented, and it is shown how this battery aids in the differential diagnosis of adductor SD and other phonatory disorders that closely mimic the vocal symptoms of adductor spasmodic dysphonia, including tremor.
How sensations get their names

There are normally four elements in any perceptual experience: a sensation or sensations, some cognitive state or states (i.e., belief states), an affective state or states (liking/disliking, among others), and some overt behavioral state or states.' The traditional theory in philosophy has been that of these four states the most important is the sensation. It is the having of a certain kind of sensation which determines what kind of perceptual experience we are undergoing. We determine what kind of sensation state we are having simply by having it, reidentify it when it recurs, and name the associated perceptual state accordingly. It is because we have visual sensations that we say we see. It is because blind people don't have these sensations that we say they don't see. It is because auditory sensations are so different from visual ones and both are so different from tactile ones, and so forth, that we say we have five (or more) kinds of perceptual experiences. And it is because the visual sensation of red is so different from the visual sensation of blue that we say one is the experience of red, the other of blue, and the like. It is because we have red sensations when confronted by certain objects that we ascribe the property "red" to those objects. Perceiving, according to this traditional theory, is essentially a sensory state. Understanding the sensation and its phenomenal properties is essential to understanding perception. I believe this picture of perceptual experiences to be quite wrong. I will argue that sensations are the least important element in perceptual experiences; that far from the nature of the sensation determining the nature of the experience, it is the nature of the experience, itself determined otherwise, that determines how we categorize the sensation: that rather than naming the sensation as a visual experience, say, simply by having it, we first name the perceptual experience, and insofar as sensations have names, they take them from the sorts of perceptual experi-
Low-barrier hydrogen bonds and enzymatic catalysis.

Abstract Short, strong (low barrier) hydrogen bonds occur when the p K values of the atoms sharing the proton are similar. The overall distance is 2.5 A or less, the deuterium fractionation factor is less than 0.5, the proton NMR chemical shift can approach 20 ppm, and deuterium or tritium substitution causes an upfield change in the chemical shift. Such bonds can have Δ H values of 25 kcal/mol in the gas phase, and at least half that in water or other high-dielectric medium. The strength of the hydrogen bond in an active site drops by ∼1 kcal/mol for each pH unit mismatch in p K s. When a weak hydrogen bond in the initial enzyme–substrate complex is converted into a low-barrier one by alteration of the p K of the substrate or catalytic group so that the p K s match, the increase in hydrogen bond strength can be used to help catalyze the reaction. A well-established example of this is the reaction catalyzed by serine proteases. The p K of neutral histidine is 14, while that of aspartate is ∼6. Proton transfer from serine to permit attack on bound substrate produces protonated histidine, with a p K now matching that of aspartate. Studies with trifluoromethyl ketone inhibitors that form tetrahedral adducts show up to five orders of magnitude in binding strength as the result of formation of a low-barrier hydrogen bond between aspartate and histidine. Other enzymes whose mechanisms appear to involve low-barrier hydrogen bonds include liver alcohol dehydrogenase, steroid isomerase, triose-P isomerase, aconitase, citrate synthase, and zinc proteases. It is likely that low-barrier hydrogen bonds form at the transition state of any reaction involving general-acid or general-base catalysis, as at that point the p K s of the catalytic group and reactant will be equal.
Trials and tribulations: Oncological antibody imaging comes to the fore

At the present time, there are three radiolabeled antibodies that have been approved by the US Food and Drug Administration (FDA) for imaging of cancer, a fourth commercially sponsored product recommended for approval (as of 10/29/96, cap romab pendetide (ProstaScint; Cytogen Corp; Princeton, NJ) was upgraded from recommended for approval to approved), and several additional agents in FDA-monitored trials. The majority of antibodies studied to date have been whole or fragmented murine monoclonals whereas the first of the human and humanized immunoglobulins are now entering clinical trials. While no antibody has behaved as a perfect imaging agent, they have consistently been shown to contribute to diagnosis, complementing and often exceeding the diagnostic ability of conventional modalities. Many promising new trends in antibody imaging, relating to the radiolabeled immunoglobulin, its route and manner of administration, and mode of detection, are under development. Because of the requisite several-year delay inherent in the (FDA) testing process, there is a lag before the most-promising of these innovations will achieve (FDA) approval and be incorporated into routine imaging studies. In spite of this effective performance, as "new kid on the block," radioimmunoscintigraphy may have often been expected to perform in an unrealistic manner, considering the great variation in biological behavior of primary and metastatic cancer and the consequent limitation of all diagnostic tests. Nonetheless, because radioimmunoscintigraphy identifies antigens on a cellular level, differing fundamentally from anatomic imaging modalities such as computed tomography and ultrasound which identify gross morphological changes, it has potential to impact significantly on patient care. With adequate resources focused on radioimmunoscintigraphy, this technology will continue to emerge as an important and unique diagnostic tool in the care of cancer patients, with demonstrable clinical efficacy and cost effectiveness.
Distance field computation for geological slab surface data sets

The three-dimensional shapes of tectonic plates that sink into the Earth’s mantle (slabs) are the starting point for a range of geoscience studies, from determining the forces driving the motion of tectonic plates, to potential seismic and tsunami hazards, to the sources of magmas beneath active volcanos. For many of these applications finite element methods are used to model the deformation or fluid flow, and therefore the input model parameters, such as feature geometries, temperature or viscosity, must be defined with respect to a smooth, continuous distance field around the slab. In this paper we present a framework for processing sparse and noisy seismic data (earthquake locations), defining the shape of the slab and computing a continuous distance function on a mesh with variable node spacing. Due to the inhomogeneous volumetric distribution of earthquakes within the slab and significant inaccuracies in the locations of earthquakes occurring hundreds of kilometers below the Earth’s surface, the seismicity data set is extremely noisy and incomplete. Therefore, the preprocessing is the major part of the framework consisting of several steps including a point based smoothing procedure, a powerful method to use other observational constraints on slab location (e.g., seismic tomography or geologic history) to extend of the slab shape beyond earthquake data set and continuous resampling using moving least squares method. For the preprocessed point data we introduce approaches for finding the three-dimensional boundary of the slab and a subdivision of the slab into quadric implicit polynomials. The resulting distance field is then compiled from distances to the piecewise continuous approximation of the slab and distances to slab boundary.
Simple pulse sequences for selective multiple-quantum excitation

Abstract A sixteen pulse sequence which excites only four-quantum transitions in multiple-quantum NMR is shown to give good selectivity on two molecules, benzene and n -butyl bromide. The behavior as pulse sequence parameters are varied is shown to be consistent with coherent averaging theory. Advantages of this new sequence include much lower duty cycles and shorter total duration than can be achieved with previously used selective sequences. Limitations of this approach and extensions to high-quantum selectivity are discussed.
Glaucomalike disks without increased intraocular pressure or visual field loss.

We studied 48 patients who had glaucomalike disks with increased cupping and pallor, superior or inferior extension of cupping and pallor and asymmetry of cupping and pallor between eyes without increased intraocular pressure or visual field loss, and open angles. We compared these patients with a randomly selected group of 48 patients with primary open-angle glaucoma. The mean age of the patients with glaucomalike disks (45.1 + 16.1 years) was significantly younger than the group with open-angle glaucoma (63.8 + 11.3 years). Of the patients with glaucomalike disks, 11 (23%) had a family history of glaucoma, 75% of 22 eyes with optic disk fluorescein angiograms had abnormal readings, and 59% of 43 eyes with retinal nerve fiber layer defects had abnormal readings. Photogrammetric measurements of the left disk cups were compared in 22 of the patients with glaucomalike disks to 16 matched patients with primary open-angle glaucoma. The only statistically significant difference was that the patients in the glaucoma group showed a larger cup area (surface opening) of the inferior quadrant. Our findings suggest that some glaucomalike disks may be one variant of primary open-angle glaucoma.
High Order Finite Difference and Multigrid Methods for Spatially Evolving Instability in a Planar Channel

A computational study of the spatial instability of planar Poiseuille flow is presented. A fourth-order finite difference with a fully implicit time-marching scheme is developed on a staggered grid. A semi-coarsening multigrid method is applied to accelerate convergence for the implicit scheme at each time step and a line distributive relaxation is developed as a fast solver, which is very robust and efficient for anisotropic grids. A new treatment for outflow boundary conditions makes the buffer area as short as one wavelength. The computational results demonstrate high accuracy in terms of agreement with linear theory and excellent efficiency in the sense that cost is comparable to (and usually less than) explicit schemes.
OSA Optics Discovery Kit: its development and use

This is a description of a project in elementary school optics education that originated through a professional society, the Optical Society of America (OSA). The purpose of this paper is to show how the project was started, the process by which the OSA Optics Discovery Kit was finally produced and distributed, and the current efforts to use the kits and to extend the idea to other educational levels. Through this discussion it is hoped that others may find both description of the kit and its generation of use in their efforts to engage the interest of youth in science
Patterns of failure after resection of non-small-cell lung cancer: implications for postoperative radiation therapy volumes.

Purpose: To analyze local-regional patterns of failure after surgical resection of non–small-cell lung cancer (NSCLC). Methods and Materials: This retrospective analysis included 61 patients who underwent resection of NSCLC at Duke University Medical Center. Inclusion into the study required the following: margin-negative resection, no neoadjuvant/adjuvant radiation therapy (RT), first recurrence involving a local-regional site, and imaging studies available for review. Sites of intrathoracic disease recurrence were documented. Diagrams were constructed that illustrated sites of failure on the basis of lobe of primary tumor. Failure rates were compared by application of a two-tailed Fisher's exact test. Results: All patients had CT imaging for review, and 54% also had PET imaging. The median number of local-regional recurrent sites was two (range, 1–6). For all patients, the most common site of failure was the bronchial stump/staple line (44%), which was present more often in those who had a wedge resection than in those who had a more radical procedure (79% vs. 34%, p = 0.005). Patients with initial nodal involvement (pN1-2) were not more likely to have involvement of the mediastinum than were patients with pN0 disease (64% vs. 72%, p = 0.72), but were more likely to have involvement of the supraclavicular fossa (27% vs. 4%, p = 0.04). Mediastinal involvement, without overt evidence of hilar involvement, occurred in 59% of patients. Left-sided tumors tended to involve the contralateral mediastinum more frequently than did right-sided tumors. Patterns of failure after resection are diagrammed and follow a fairly predictable pattern on the basis of involved lobe. Conclusions: These data may help clinicians construct postoperative RT volumes that are smaller than ones traditionally utilized, which may improve the therapeutic ratio.
Least-Squares Adaptive Control Using Chebyshev Orthogonal Polynomials

This paper presents a new adaptive control approach using Chebyshev orthogonal polynomials as basis functions in a least-squares functional approximation. The use of orthogonal basis functions improves the function approximation significantly and enables better convergence of parameter estimates. Flight control simulations demonstrate the effectiveness of the proposed adaptive control approach.
HELPING SUBORDINATES WITH THEIR PERSONAL PROBLEMS: A MORAL DILEMMA FOR MANAGERS

When subordinates ask their managers for help with their personal problems, it creates moral dilemmas for their managers. Managers are contractually obliged to maintain equivalent relations between their subordinates and that is compromised when one subordinate makes this kind of request. By applying deontological principles to this dilemma, additional options are revealed, and the moral duties managers owe their subordinates in these situations are clarified.
Synthesis and pharmacological study of a polymer which selectively binds mercury

A polymeric chelating agent (MBP) prepared by condensation of a mercaptoethyl sulfide with a terephthaldicarboxaldehyde exhibited a high degree of specificity for mercury (II) as judged by its ability to reduce rapidly the free metal ion concentration in an aqueous solution. The polymer exhibited a low degree of toxicity (LD50 > 5 g/kg) when administered orally to mice, and it was capable of antagonizing acute methyl mercury-induced lethality. MBP at a level of 1% in food promoted a rapid clearance of mercury from the body after acute administration of methyl mercury. The biological half-life of the metal was reduced from 10.0 days to 4.5 days. The concentration of mercury in various tissues including the brain was reduced 40 to 70% after administration of MBP when compared to contents obtained in animals not treated with MBP.
Perceptions and predictions of cardiovascular disease of Alabama women in a rural county

Abstract Purpose The aim of this project was to gain a better understanding of cardiovascular disease (CVD) as a women's health issue among Alabama women in a rural county. Research Questions 1.What are the risks and perceptions of CVD of Alabama women in a rural county? 2.What demographic and study variables predict CVD? Methods One hundred twelve women participated in this descriptive, prospective study. Findings Thirty percent identified CVD as the greatest health problem facing women and the leading cause of death in women. Ninety percent believed that they had a 41% or greater chance of developing CVD. The variables in the study explained 60% of the participant's coronary heart disease risk prediction scores. Conclusions The understanding gained in this study will be used to find ways to increase the awareness of CVD and to design interventions that improve the cardiovascular health of women in a rural area of Alabama.
Reduced syndecan-4 expression in arterial smooth muscle cells with enhanced proliferation

Syndecans, a family of cell surface heparan sulfate (HS) containing proteoglycans (PGs), are known regulators of many biological processes including inhibition of smooth muscle cell (SMC) proliferation. Cultured arterial SMCs from atherosclerosis-susceptible White Carneau (WC) pigeons have increased proliferation rates and significant reductions in total cell-surface HS relative to atherosclerosis-resistant Show Racer (SR) SMC. Using a specific syndecan-4 cDNA, 1.5- to 2.0-fold reductions in gene expression were observed in WC SMC compared to SR SMC. Immunolocalization studies demonstrated reduced cell surface syndecan-4 protein in WC cells. Gene induction demonstrated that the reduction in syndecan-4 expression in WC cells was not due to reduced mRNA stability. Studies using cycloheximide to superinduce gene expression indicated transcriptional suppression of syndecan-4 in WC cells. The results suggest that reduced cell surface HS PG in WC arterial SMC can be explained, in part, by reductions in syndecan-4 gene expression. Differential transcriptional regulation of syndecan-4 in WC and SR cells provides a system to explore regulation of the syndecan-4 gene as well as the potential mechanisms by which syndecan-4 can exert a specific antiproliferative effect.
Valence-doorway model for radiative capture

Abstract A model of radiative capture is presented in which the T-matrix for valence capture is expressed as the sum of three terms, viz., a direct capture term, a term that describes the coupling between a single-particle resonance and the many possible continuum channels, and a pure single-particle resonance term. Expressions for the target excitations are not explicitly included, and projection operators are used to break up the single-particle space into resonant and nonresonant parts. The spreading of single-particle resonances is described through the coupling to particle-vibration doorways. The model is applied to the cases of 98Mo(n, γ) 99Mo and 92Mo(n, γ) 93Mo for an energy range of 0–3 MeV. In these cases the single-particle resonance amplitude is overwhelmingly dominant, and doorway effects are found to be relatively unimportant. Radiative widths obtained from our calculated average cross sections are compared to the corresponding widths obtained by averaging over the detailed fine structure measurements of Chrien et al. for 99Mo. Good agreement is obtained. The valence capture cross section in 93Mo is considerably smaller than in 99Mo. This is consistent with the measurements of Chrien et al. and in good agreement with a recent analysis by Soloviev and Voronov.
The determination of the mass and mean density of Enceladus from its observed shape

Application of limb-fitting methods to the 11 best Voyager 2 images of Enceladus has shown that the shape of this satellite is closely represented by a triaxial ellipsoid. The observed ratio of the differences of the principal axes F = (b - c)/(a - c) is 0.23 (sup +0.04 sub - 0.01), consisting with the value F = 0.23 expected for a synchronously rotating satellite in hydrostatic equilibrium. We also deduce from the Voyager observations, after allowing for limb topography, that the mean radius of the satellite is 249.4 +/- 0.2 km. For satellites of known mass, measurement of the size and shape leads to a determination of the satellite's mean density and moment of inertial. We have used this method to determine the moments of inertia of Mimas (1988) and Tethys (1991). Enceladus appears to be hydrostatically relaxed, making it an ideal candidate for this type of analysis. However, none of the Pioneer or Voyager spacecraft had a close encounter with this satellite and thus its mass is effectively unknown. Enceladus is trapped in a 2:1 orbit-orbit resonance with Dione, but the amplitudes of libration are too small to allow a useful mass determination. Using the observed shape alone, without any other assumptions other than that the satellite is in hydrostatic equilibrium at its present orbital radius, we place an upper bound on the mean density of 1.12 +/- 0.05 g/cu cm. Thus, the mean density of Enceladus is probably little more than that of water-ice and we conclude that this satellite is markedly deficient in rock. If the mass of a satellite is unknown, but the satellite is differentiated and has a deep mantle of known composition, then we show that measurement of the shape alone can lead to a determination of the satellite's mass, mean density, and moment of inertia. Application of this method to Enceladus, assuming that the satellite has a deep mantle of water-ice of density 0.93 g/cu cm, gives the result that the mean density of the satellite is 1.00 +/- 0.03 g/cu cm. This result fills the one remaining gap in our knowledge of the structure of the Saturnian satellite system. We now know the mean densities of all the primary Saturnian satellites in the sequence from the coorbital satellites, Janus and Epimetheus, through to the outer satellite Iapetus (the densities of the small, secondary satellites in Trojan-type orbits are still unknown). The Saturnian system possesses two striking features. (1) Because of significant porosity, the mean material densities of the satellites Janus, Epimetheus, and Mimas could be substantially greater than the apparent mean densities of these satellies. (2) The densities of the satellites are not correlated with their distances from the planet; in particular, the satellites Enceladus and Tethys have lower mean densities than their interior and exterior neighbors, Mimas and Dione. This may be the result of gross postformation redistribution of rock and ice, possibly due to satellite disruptions are suggested by Smith et al. (1982).
Non-Coding Data in KCNH2 mRNA Control Translation and Trafficking Efficiencies

The KCNH2 gene encodes a K+ channel important to normal cardiac electrophysiology. Its significance is underscored by its link to both hereditary (locus LQT2) and acquired Long-QT cardiac arrhythmias. Over 400 deleterious mutations have been reported throughout the KCNH2 length. Why the channel is so susceptible to missense mutations is unclear. More than 50% of LQT2 mutations result in defective assembly and trafficking. There is evidence that even wild type channels are processed inefficiently. It has also been reported that the channel protein may reach the surface via atypical pathways. Most attention has logically focused on the protein for these processes.Much less is known about mRNA-dependent factors in channel processing. We analyzed the coding mRNA sequence of KCNH2. It has 66% GC content and 60 potential hair-pin loop segments. We re-synthesized the cDNA to achieve 50% GC-content and reduce the number of potential hair-pin loops while maintaining identical amino acid coding. Cellular expression of the codon-modified cDNA (CM-KCNH2) produced ionic currents comparable to native cDNA. Channel protein was expressed in a dramatically different pattern. Whereas the native protein (NT-KCNH2) is usually more abundant (immature form) in ER/Golgi compartments than on the surface, CM-KCNH2 showed a preponderance of the mature form, indicating channels at the surface. Immunofluorescence analysis confirmed this localization. From these results we hypothesize that KCNH2 translation efficiency, determined by RNA sequence-specific elements independent of coding, affect downstream protein assembly and/or trafficking_an unusual occurrence. As a corollary to this, we postulate a synergy between the inherently inefficient biosynthesis of KCNH2 and LQT2 mutations that contribute to the pathogenesis of hereditary LQT2. Further investigation of mechanisms underlying mRNA-dependent processing of KCNH2 channels may lead us to reconsider approaches to hereditary and acquired arrhythmia syndromes.
Prediction of protein--ligand interactions: the complex of porcine pancreatic elastase with a valine-derived benzoxazinone.

Prior to availability of the crystal structure of the complex, we evaluated models of the complex between porcine pancreatic elastase and a t-Boc–Val-derived benzoxazinone inhibitor. Models of the noncovalent and covalent complex were generated using computer graphics and each model was subjected to energy minimization using molecular mechanics. After the crystal structure became available, we found that the model with the lowest energy was in good agreement with the crystal structure, except for the position of the His57 side chain. Permissible conformations of the inhibitor were based on information from x-ray crystal structures and an earlier conformational energy investigation of t-Boc–amino acids. We did not, however, limit ourselves to these conformations. The conformation of the inhibitor in the lowest energy model and crystal structure, was not similar to any of the minimum-energy conformations of t-Boc–amino acids. This suggests that limiting proposed binding modes only to the lowest energy conformations of a ligand (prior to binding) may sometimes unfairly bias the procedure.
Theoretical performance of an HF chemical CW laser

Abstract A quantitative analysis of an HF cw chemical laser is presented that includes the influence of stimulated emission on the reacting medium. The numerically determined solutions encompass one-dimensional fluid mechanics, chemical kinetics, radiative de-excitation, and their mutual interaction. A comprehensive parametric study examines the effects due to changed plenum conditions, mixture ratios and cavity parameters. Best efficiency is obtained when the pumping is by the F + H2 reaction. Pumping by the chain reaction sequence F + H2 → HF(υ ≤ 3) + H and H + F2 → HF(υ ≤ 6) + F results in substantially lower efficiencies due to increased HF-HF vibration-translation deactivation. Detailed discussions are presented of (1) vibration-vibration and vibration-translation energy exchange, (2) chemical efficiency, (3) mechanisms that cause lasing termination, and (4) cavity operation with a selective grating.
Optimum mask and source patterns to print a given shape

New degrees of freedom can be optimized in mask shapes when the source is also adjustable, because required image symmetries can be provided by the source rather than the collected wavefront. The optimized mask will often consist of novel sets of shapes that are quite different in layout from the target IC patterns. This implies that the optimization algorithm should have good global convergence properties, since the target patterns may not be a suitable starting solution. We have developed an algorithm that can optimize mask and source without using a starting design. Examples are shown where the process window obtained is between 2 and 6 times larger than that achieved with standard RET methods. The optimized masks require phase shift, but no trim mask is used. Thus far we have only optimized 2D patterns over small fields (periodicities of approximately 1 micrometer or less). We also discuss mask optimization with fixed source, source optimization with fixed mask, and the re-targeting of designs in different mask regions to provide a common exposure level.
Interaction between STAT-3 and HNF-3 Leads to the Activation of Liver-Specific Hepatitis B Virus Enhancer 1 Function

The signal transducer and activator of transcription 3 (STAT-3), a member of the STAT family of proteins, binds to a large number of transcriptional control elements and regulates gene expression in response to cytokines. While it binds to its cognate nucleotide sequences, it has been recently shown to directly interact with other transcriptional factors in the absence of DNA. We report here one such novel interaction between STAT-3 and hepatocyte nuclear factor 3 (HNF-3) in the absence of DNA. We have identified a STAT-3 binding site within the core domain of hepatitis B virus (HBV) enhancer 1. The HBV enhancer 1 DNA-STAT-3 protein interaction is shown to be stimulated by interleukin-6 (IL-6) and epidermal growth factor, which leads to an overall stimulation of HBV enhancer 1 function and viral gene expression. Using mobility shift assays and transient transfection schemes, we demonstrate a cooperative interaction between HNF-3 and STAT-3 in mediating the cytokine-mediated HBV enhancer function. Cytokine stimulation of HBV gene expression represents an important regulatory scheme of direct relevance to liver disease pathogenesis associated with HBV infection.
An experience in collaborative learning: observations of a software engineering course

I describe my experiences in teaching an advanced graduate-level software engineering course using a collaborative approach. Software Engineering II (SEII) is the second of two graduate software engineering courses taught at Rensselaer at Hartford, a branch of the Rensselaer Polytechnic Institute that provides professional master's degrees in computer science. During the past three offerings of SEII, I have attempted to create a collaborative learning environment which would support both peer-based learning and life-long learning through the employment of such techniques as cooperative construction of mental models, brainstorming and collaboration by example. This paper provides details on the techniques that were used in SEII, describes my observations on the constraints and successes of my approach, and outlines some thoughts for future directions for SEII.
Fetal Alcohol Spectrum Disorders and Abnormal Neuronal Plasticity

The ingestion of alcohol during pregnancy can result in a group of neurobehavioral abnormalities collectively known as fetal alcohol spectrum disorders (FASD). During the past decade, studies using animal models indicated that early alcohol exposure can dramatically affect neuronal plasticity, an essential property of the central nervous system responsible for the normal wiring of the brain and involved in processes such as learning and memory. The abnormalities in neuronal plasticity caused by alcohol can explain many of the neurobehavioral deficits observed in FASD. Conversely, improving neuronal plasticity may have important therapeutic benefits. In this review, the author discuss the mechanisms that lead to these abnormalities and comment on recent pharmacological approaches that have been showing promising results in improving neuronal plasticity in FASD.
Four crystal forms of a Bence-Jones protein

Four crystal forms have been grown and characterized by X-ray diffraction of a Bence-Jones protein collected from the urine of a multiple myeloma patient more than 40 years ago. Closely related tetragonal and orthorhombic forms belonging to space groups P43212 and P212121, with unit-cell parameters a = b = 68.7, c = 182.1 and a = 67.7, b = 69.4, c = 87.3 A, diffract to 1.5 and 1.9 A, respectively. Two closely related trigonal forms, both belonging to space group P3121 with unit-cell parameters a = b = 154.3 A but differing by a doubling of the c axis, one 46.9 A and the other 94.0 A, diffract to 2.9 and 2.6 A resolution, respectively. The trigonal crystal of short c-axis length shows a positive indication of twinning. The trigonal crystal of longer c axis, which appeared only after eight months of incubation at room temperature, is likely to be composed of proteolytically degraded molecules and unlike the other crystal forms contains two entire Bence-Jones dimers in the asymmetric unit. This latter crystal form may shed some light on the formation of fibrils common to certain storage diseases.
Observers for systems with nonlinearities satisfying an incremental quadratic inequality

We consider the problem of designing observers to asymptotically estimate the state of a system whose non-linear time-varying terms satisfy an incremental quadratic inequality that is parameterized by a set of multiplier matrices. Observer design is reduced to solving linear matrix inequalities for the observer gain matrices. The proposed observers guarantee exponential convergence of the state estimation error to zero. In addition to considering a larger class of nonlinearities than previously considered, this paper unifies some earlier results in the literature. The results are illustrated by application to a model of an underwater vehicle.
Physician misdiagnosis of dehydration in older adults.

Introduction Dehydration is a difficult clinical diagnosis in older adults because the physical signs of dehydration are often confusing. The clinical consequences of a diagnosis of dehydration are critical, since dehydration implies increased morbidity and mortality and aggressive rehydration can improve clinical outcome. The diagnosis is a sentinel event for nursing homes, and often is made at transfer to a hospital. Objective To define the accuracy of the clinical diagnosis of dehydration during hospital admission, and to observe persons admitted from long-term care. Methods A total of 102 consecutive medical admissions in persons older than 65 years with a diagnostic coding for dehydration either on admission or during the course of hospitalization over a 3-month period at a university teaching hospital were reviewed. The diagnosis of dehydration was considered confirmed if the calculated serum osmolarity was greater than 295 milliosmols (mOsmol). Subjects were considered to have intravascular volume depletion if the ratio of blood urea nitrogen (BUN) to serum creatinine was greater than 20 or the serum sodium was greater than 145 milligrams per deciliter. Subjects were considered to have hypovolemia if the serum osmolarity was greater than 295 and the BUN/creatinine ratio was greater than 20. Results Among subjects with a clinical diagnosis of dehydration, only 17% had a serum osmolarity >295 mOsm, and only 11% had a serum sodium greater than 145. A BUN/creatinine ratio greater than 20 was present in 68% of the subjects. Clinicians appear to be using the term dehydration synonymously with intravascular volume depletion. Even so, at least a third of the diagnoses of intravascular volume depletion in older adults were incorrect based on laboratory data. Conclusion Physicians who diagnose dehydration during hospital admission may be relying more on physical signs than laboratory data. Little change in laboratory markers for hydration status occurs from the time of diagnosis to hospital discharge, suggesting that the clinical diagnosis does not affect fluid management. The data suggest a need for improvement in the differential diagnosis and management of volume changes in older persons.
Reads and writes: when I/Os aren't quite the same

Redundant disk arrays are gaining increased attention as a feasible I/O organization. In these I/O systems, reads and writes to the system have different performance implications. A write operation actually results in more than one I/O operation. The I/O system's performance and its organization hence depends on the relative costs of read/write operations and their relative frequency in I/O workloads. The author characterizes the read/write behavior of I/O workloads and how caches affect these characteristics. The characterization, based on real traces, is expected to give a clearer understanding of the performance implications for the I/O system. It has been a widely held belief that disk caches increase the percentage of write requests going to the disk. It is shown through analysis and simulations that this may not be the case and in some cases the disk cache can decrease the percentage of write requests going to the disk. >