cssi/SciSciGPT-SciSciNet huggingface dataset:
Flow cytometric analysis of human antigen-specific T-cell proliferation.

Publisher Summary This chapter reviews the use of a technique based on serial dilution of a stably binding intracellular fluorochrome, carboxy fluorescein diacetate succinimidyl ester (CFSE) that allows monitoring of cell division by flow cytometry, to monitor antigen-specific T-cell responses. CFSE is capable of freely diffusing across the cell membrane where it reacts with free amine groups of cellular proteins. Carboxyl groups are removed from CFSE by enzymatic action of ubiquitously expressed esterases and CFSE emits strongly at 519 nm after excitation by 488 nm argon laser light. Advantages of monitoring cell division by flow cytometry over traditional thymidine incorporation assays are (1) number of cell divisions can be directly quantified using the flow cytometric assay, (2) phenotype of cells undergoing proliferation can be directly ascertained, (3) phenotypic changes and other properties that occur with respect to cell division can be monitored, and (4) flow cytometric analysis of proliferation allows for sorting of viable cells and based on rounds of proliferation. The critical aspects to be taken care of when using CFSE staining are background proliferation and instrument compensation. The CFSE technology adds a huge advantage over assays using incorporation of tritiated thymidine because these proliferation platform calculations cannot be performed with tritiated thymidine experiments. Monitoring cell division in conjunction with production of effector cytokines might enable detection of more vaccine-induced antigen-specific T cells. Flow cytometric technology, capable of monitoring more than six fluorescent parameters, is slowly becoming more widespread. Such technology will allow dissection of cytokine production and cell division within defined of phenotypically distinct lymphocytes.
Radioimmunoassay of urinary estrogens

Abstract A radioimmunoasay for urinary estrogens is described. Following hydrolysis of urine samples, the estrogens are extracted with ether and separated by thin-layer chromatography. Antiserum obtained from rabbits immunized with estradiol-17β-succinyl bovine serum albumin is used in radioimmunoassay. Ammonium sulfate precipitation is employed to separate free and antibody-bound radioactivity. The lower level of sensitivity of radioimmunoassay is 15.6 pg. per milliliter for estrone and estradiol-17β and 62.5 pg. per milliliter for estradiol.
A dynamic reaction cell for inductively coupled plasma mass spectrometry (ICP-DRC-MS). Part III. Optimization and analytical performance

The dynamic reaction cell (DRC) is a rf/dc quadrupole which may be pressurized with a reactive gas in order to promote ion–molecule reactions intended to suppress plasma-based isobaric interferences for trace elemental analysis. The bandpass of the DRC is adjusted in order to suppress the appearance of new interferences produced through sequential reactions within the reaction cell. The DRC may alternatively be operated at low pressure (vented, under collision-free conditions) to emulate conventional ICP-MS. A practical optimization procedure for both the vented and pressurized modes is described, with examples showing the suppression of both plasma-based and cell-based isobaric interferences. The analytical performance characteristics of the instrument, including efficiency of isobar rejection, detection limits in clean water and in neat hydrogen peroxide, short- and long-term stability, determination of arsenic in chloride solution and Se isotope determination, are provided.
Grid Application Design Using Software Components and Web Services

Software Component systems are widely used in the commercial world for designing desktop applications and multi-tier business systems. They have not been widely used in large scale scientific computation. However, as our computing platform has evolved into Grid systems, a distributed component architecture is gaining support as a programming model for building heterogeneous, wide-area application. There are several interesting Grid component architectures that are currently being used. Some are derived from the Corba component model and others are based on EJB or other object systems. The DOE CCTTSS organization has developed a model that supports parallel applications as well as distributed computation called CCA. Components in CCA are defined by public interfaces called "ports" which define the endpoints in the communication channels that link an application's components together.
Optimal Monetary Policy with Uncertain Fundamentals and Dispersed Information

This paper studies optimal monetary policy in a model where aggregate fluctuations are driven by the private sector's uncertainty about the economy's fundamentals. Information on aggregate productivity is dispersed across agents and there are two aggregate shocks: a standard productivity shock and a "noise shock" affecting public beliefs about aggregate productivity. Neither the central bank nor individual agents can distinguish the two shocks when they are realized. Despite the lack of superior information, monetary policy can affect the economy's relative response to the two shocks. As time passes, better information on past fundamentals becomes available. The central bank can then adopt a backward-looking policy rule, based on more precise information about past shocks. By announcing its response to future information, the central bank can influence the expected real interest rate faced by forward-looking consumers with different beliefs and thus affect the equilibrium allocation. If the announced future response is sufficiently aggressive, the central bank can completely eliminate the effect of noise shocks. However, this policy is typically suboptimal, as it leads to an excessively compressed distribution of relative prices. The optimal monetary policy balances the benefits of aggregate stabilization with the costs in terms of cross-sectional efficiency. Copyright , Wiley-Blackwell.
Porphyrin-lipoprotein association as a factor in porphyrin localization

Systemic administration of the tumor-localizing product hematoporphyrin derivative (HPD) to mice bearing the Lewis-Lung tumor leads to an initial distribution of porphyrins among plasma lipoproteins and albumin. The more hydrophobic components of HPD (including the tumor-localizing fraction) preferentially bind to plasma low density lipoprotein (LDL) and high density lipoprotein (HDL). After 48 h, the remaining plasma porphyrins are mainly bound to HDL. The distribution pattern of HPD is correlated with the relative numbers of LDL receptors in different tissues.
Rigid body motion estimation using a sequence of images from a static camera

Rigid body motion estimation using a sequence of images from a static cameraG. V. S. Raju* and Prasad Rudraraju**Department of Electrical and Computer EngineeringStocker CenterOhio UniversityAthens, Ohio 45701ABSTRACTThis paper is concerned with the evaluation of motion parameters by observingfour features in camera acquired images. The motion parameters of a moving objectare studied using a static camera. The principles of distance invariance betweenrigid points and angular invariance between fixed lines are used in the method.2. INTRODUCTIONMeasurement of motion is necessary for autonomous navigation, military appli-cations, weather predictions, robotic applications, etc. In a dynamic workenvironment where a robot is employed, it is essential to detect a moving objectand compute its motion parameters to avoid any accidents or collisions.Motion analysis can be done either by optical flow approach or feature basedapproach. Computation of optical flow is difficult and highly sensitive to noise.Feature based approach depends on segmenting images, extracting features andmatching these features between different images depicting motion. These featurescould be points, lines, contours, etc.Mitiche et.al.' addressed the problem of computing the structure and motionfrom the observation of five points in two distinct images of a scene. The for-mulation of equations involved exploits the principle of conservation of distanceduring rigid body motion.In another paper2 they described a method to compute the structure and motionof a set of lines in space by the observation of four lines in three views.Huang et. al.3 presented an approach based on locally constant angular momen-
Maize csmd1 exhibits pre-meiotic somatic and post-meiotic microspore and somatic defects but sustains anther growth

Maize male reproductive development is complex and lengthy, and anther formation and pollen maturation are precisely and spatiotemporally regulated. Here, we document that callose, somatic, and microspore defect 1 (csmd1), a new male-sterile mutant, has both pre-meiotic somatic and post-meiotic gametophyte and somatic defects. Chromosome behavior and cell developmental events were monitored by nuclear staining viewed by bright field microscopy; cell dimensions were charted by Volocity analysis of confocal microscopy images. Aniline blue staining and quantitative assays were performed to record callose deposition, and expression of three callose synthase genes was measured by qRT-PCR. Despite numerous defects and unlike other maize male-sterile mutants that show growth arrest coincident with locular defects, csmd1 anther elongation is nearly normal. Pre-meiotically and during prophase I, there is excess callose surrounding the meiocytes. Post-meiotically csmd1 epidermal cells have impaired elongation but excess longitudinal divisions, and uninucleate microspores cease growth; the microspore nucleoli degrade followed by cytoplasmic vacuolization and haploid cell collapse. The single vascular bundle within csmd1 anthers senesces precociously, coordinate with microspore death. Although csmd1 anther locules contain only epidermal and endothecial cells at maturity, locules are oval rather than collapsed, indicating that these two cell types suffice to maintain an open channel within each locule. Our data indicate that csmd1 encodes a crucial factor important for normal anther development in both somatic and haploid cells, that excess callose deposition does not cause meiotic arrest, and that developing pollen is not required for continued maize anther growth.
“Aluminum's disease” and Alzheimer's disease

Abstract The excellent review of Dr. Crapper McLachlan contributes to clarifying and strengthening the evidence that aluminum is a powerful neurotoxic substance. At this time, however, the proof that aluminum plays a role in the etiology or pathogenesis of Alzheimer's disease remains elusive.
Mechanism of hyperalimentation in the suppression of upper gastrointestinal secretions.

Summary The effects of hyperalimentation fluid and its component parts on upper gastrointestinal secretion were studied. Dextrose was responsible for most but not all of the suppression of gastrointestinal secretions. Five per cent amino acids suppressed the secretion of bilirubin and total protein. The combined effects of the glucose and amino acid infusion were additive.
LIPID ANALYSIS OF FILLETS FROM GIANT GRENADIER (ALBATROSSIA PECTORALIS), ARROW‐TOOTH FLOUNDER (ATHERESTHES STOMIAS), PACIFIC COD (GADUS MACROCEPHALUS) AND WALLEYE POLLOCK (THERAGRA CHALCOGRAMMA)

In Alaska, walleye pollock (WP [Theragra chalcogramma]) and Pacific cod (PC [Gadus macrocephalus]) are harvested in large amounts. There are also large biomasses of arrow-tooth flounder (ATF [Atheresthes stomias]) and giant grenadier (GG [Albatrossia pectoralis]) available in Alaskan waters; however, these fish are underutilized. The objective of this study was to determine lipid content, lipid class distribution and fatty acid (FA) profiles of fillets from these four fish species. Fat content and percent triacylglycerides (TAG) in ATF was significantly higher than in other species, and percent phospholipids (PL) was lower (P < 0.05). PC had the highest levels of omega-3 (ω-3) FA, whereas ATF had the lowest. The ratio of ω-3/omega-6 (ω-6) FA was significantly higher in ATF than in other species. Percent polyunsaturated and saturated FA's were equivalent in ATF; however, other species showed at least twice as much polyunsaturated FA as saturated FA. This study provided comparisons of the lipid characteristics in the two most abundant white fish harvested in Alaska and two other abundant but underutilized species.
A comparison of NEAR actual spacecraft costs with three parametric cost models

Abstract Costs for modern (post-1990) U.S.-built small planetary spacecraft have been shown to exhibit significantly different trends from those of larger spacecraft. These differences cannot be accounted for simply by the change in size alone. Some have attributed this departure to NASA's “faster, better, cheaper” design approach embodied by the efficiency of smaller teams, reduced government oversight, increased focus on cost, and short development periods. With the Discovery, Mars Surveyor and New Millennium programs representing the new approach to planetary exploration, it is important to understand these current cost trends and to be able to estimate costs of future proposed missions. To address this issue, The Aerospace Corporation (hereafter referred to as Aerospace) performed a study to compare the actual costs of the Near Earth Asteroid Rendezvous (NEAR) spacecraft bus (instruments were not estimated) using three different cost models; the U.S. Air Force Unmanned Spacecraft Cost Model, Version 7 (USCM-7), the Science Applications International Corporation (SAIC) NASA/Air Force Cost Model 1996 (NAFCOM96) and The Aerospace Corporation's Small Satellite Cost Model 1998 (SSCM98). The NEAR spacecraft was chosen for comparison because it was the first Discovery mission launched, and recently recognized with a Laurel award by Aviation Week and Space Technology as a benchmark for NASA's Discovery program [North, 1997]. It was also selected because the cost data has been released into the public domain [Hemmings, 1996]which makes it easy to discuss in a public forum. This paper summarizes the NEAR program, provides a short synopsis of each of the three cost models, and demonstrates how they were applied for this study.
EXAFS STUDIES OF AlMnSi AND AlMn PERIODIC AND APERIODIC ALLOYS

Resultats obtenus par transformation de Fourier pour la fonction de distribution radiale pour la premiere couche d'atomes d'aluminium. La methode EXAFS fournit une fonction de distribution de meilleure resolution et moins sensible aux incertitudes liees a l'ajustement d'un modele
Textile Production in the Communalistic German Colony at Bethel, Missouri: 1844-1879

A collection of textiles believed to have been produced in a German communalistic colony in Bethel, Missouri was investigated. Objectives of the study were to determine which, if any, of the textil...
Oligonucleotide Loading Determines Cellular Uptake of DNA-Modified Gold Nanoparticles

The cellular internalization of oligonucleotide-modified nanoparticles is investigated. Uptake is dependent on the density of the oligonucleotide loading on the surface of the particles, where higher densities lead to greater uptake. Densely functionalized nanoparticles adsorb a large number of proteins on the nanoparticle surface. Nanoparticle uptake is greatest where a large number of proteins are associated with the particle.
Collisional redistribution by laser-induced fluorescence in the Ba-Ar system

The effects due to the presence of a (possibly intense) probe laser, which is used to interrogate the asymptotic excited-${m}_{j}$-state distribution resulting from the evolution through a half-collision, are systematically studied. Experimental results are obtained which are in good qualitative agreement with predictions based on a recent theoretical treatment. Finally, a simple interpretation of the relevant physical processes involved is suggested by considering the problem within a dressed-state representation.
Application of simulation modeling to lipid peroxidation processes.

Abstract A quantitative simulation model was developed that utilized present knowledge of lipid peroxidation in biological systems. The simulation model incorporated the following features: peroxidizability of polyunsaturated lipids, activation of inducers and their initiation of lipid peroxidation, concurrent autoxidation, inhibition of lipid peroxidation by vitamin E, reduction of some of the hydroperoxides by glutathione peroxidase, and formation of thiobarbituric acid-reactive substances. Simulation calculations were done using a computer spreadsheet program. When the stimulation program was applied to tissue slice and microsomal peroxidizing systems, the results of the simulation were in agreement with the experimental data.
The effects of young embedded groups and clusters on forming solar systems

Most stars—and hence most solar systems—form within groups or clusters. This contribution discusses how these star forming environments affect the planetary systems forming within them. The discussion starts with the dynamical evolution of young stellar clusters with N=100–1000 members. We use N-body simulations to explore how evolution depends on system size N and the initial conditions. Motivated by recent observations, this study compares subvirial and virial starting states. Multiple realizations of equivalent cases (100 simulations per case) are used to build up a robust statistical description of these systems, e.g. distributions of closest approaches and distributions of radial locations. These results provide a framework from which to assess the effects of clusters on planet formation. The distributions of radial positions are used in conjunction with far ultraviolet (FUV) luminosity distributions to determine the radiation exposure of circumstellar disks. Photoevaporation calculations then determine the efficacy of radiation in removing gas from the systems (resulting in loss of planet forming potential). The distributions of closest approaches are used in conjunction with scattering cross-sections (calculated from 100 000 numerical experiments) to determine the probability of solar system disruption. Our main result is that clusters in this size range can have a significant effect on forming planetary systems, and we have quantified the size of these effects. For example, in modest-sized clusters, FUV radiation typically leads to disk photoevaporation down to outer disk radii of 30–50 AU.
PNEUMOSCROTUM AFTER DIAGNOSTIC PERITONOSCOPY

Peritonoscopy is a widely used procedure in diagnosis and surgery with few post-procedural complications. We report a case in which pneumoscrotum occurred as a procedural complication of peritonoscopy. Anatomic considerations are considered. The condition resolves without therapy, and only patient reassurance is indicated.
Kinetic analysis and fragment screening with Fujifilm AP-3000.

Abstract We evaluated the performance of Fujifilm’s new AP-3000 surface plasmon resonance biosensor for kinetic analysis and fragment screening. Using carbonic anhydrase II as a model system, we characterized a set of 10 sulfonamide-based inhibitors that range in molecular mass from 98 to 341 Da and approximately 10,000-fold in affinity (0.4 mM to 20 nM). Although the data collected from the AP-3000 were generally similar to those collected using a Biacore T100, the AP-3000’s stop-flow analyte delivery system complicated the shapes of the association- and dissociation-phase binding responses. We illustrate how reasonable estimates of the kinetic rate constants can be extracted from AP-3000 data by limiting data analysis to only the regions of the responses collected during flow conditions. We also provide an example of the results obtained for a fragment-screening study with the AP-3000, which is the ideal application of this technology.
The Structure of Circumstellar Envelopes

Copious mass loss on the Asymptotic Giant Branch dominates the late stages of stellar evolution. Maps of extended circumstellar envelopes provide a history of mass loss and trace out anisotropic mass loss. This review concentrates on observations of millimeter wavelength molecular line emission, on high resolution maps of maser emission and on observations of submillimeter, millimeter and radio wavelength continuum emission. Radio continuum observations show that AGB stars are larger at radio than at optical wavelengths. The extended chromospheres indicated by these observations extend to distances from the star large enough for dust to form, thereby initiating mass loss. Molecular line maps have found time-variable mass loss for some stars, including detached shells indicating interrupted mass loss and evidence for a rapid increase in the mass loss rate at the end of the AGB phase. Maps of circumstellar envelopes show evidence of flattening, bipolar outflow and angular variations in both the mass loss rate and the outflow velocity. As stars evolve away from the AGB and planetary nebula formation begins, these structures become more pronounced, and fast bipolar molecular winds are observed. The time scales derived from the dynamical times of these winds and from the expansion rates of the central planetary nebulae are very rapid in some cases, about 100 years, in agreement with the predictions of stellar evolution theory.
DNA array profiling of gene expression changes during maize embryo development.

We are using DNA microarray-based gene expression profiling to classify temporal patterns of gene expression during the development of maize embryos, to understand mRNA-level control of embryogenesis and to dissect metabolic pathways and their interactions in the maize embryo. Genes involved in carbohydrate, fatty acid, and amino acid metabolism, the tricarboxylic acid (TCA) cycle, glycolysis, the pentose phosphate pathway, embryogenesis, membrane transport, signal transduction, cofactor biosynthesis, photosynthesis, oxidative phosphorylation and electron transfer, as well as 600 random complementary DNA (cDNA) clones from maize embryos, were arrayed on glass slides. DNA arrays were hybridized with fluorescent dye-labeled cDNA probes synthesized from kernel and embryo poly(A)+RNA from different stages of maize seed development. Several characteristic developmental patterns of expression were identified and correlated with gene function. Patterns of coordinated gene expression in the TCA cycle and glycolysis were analyzed in detail. The steady state level of poly(A)+ RNA for many genes varies dramatically during maize embryo development. Expression patterns of genes coding for enzymes of fatty acid biosynthesis and glycolysis are coordinately regulated during development. Genes of unknown function may by assigned a hypothetical role based on their patterns of expression resembling well characterized genes. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at http://dx.doi.org/10.1007/s10142-002-0046-6.
Falls from height: spine, spine, spine!

Background Falls from a height are a major cause of morbidity and hospital cost. Spinal injury is frequently associated with falls from height, but reliable predictive factors have not been identified. Diagnostic evaluation of the spine is complex and debated. Our objective was to characterize spinal injury after falls from height and identify predictive factors of spinal injuries. Study design Medical records of patients with falls from height > 10 feet admitted in a Level I trauma center during a period of 66 months were reviewed. Univariate and multivariate analyses were performed to identify independent risk factors of spinal injuries. Results Of 414 patients, 127 (31%) suffered 277 spinal injuries. Multiple spinal injuries at different levels were found in 62 (49%) patients; in 19 (15%) spinal injuries were at noncontinuous levels. The only independent predictor of spinal injury was alcohol intoxication (odds ratio=3.305; 95% CI, 1.75−6.242; p Conclusions Spinal injury is frequent among survivors of falls from height > 10 feet. Because of the absence of reliable predictors of spinal injury, the possibility of multiple noncontinuous fractures, and the presence of distracting injuries clouding the clinical presentation, aggressive evaluation of the entire spine is warranted.
Late Manifestation of Coarctation of the Aorta After Arterial Switch Operation for D-Transposition of the Great Arteries With Intact Ventricular Septum

We describe an infant with D-transposition of the great arteries with an intact ventricular septum who developed coarctation of the aorta 13 days after arterial switch operation. A mildly hypoplastic aortic isthmus was present on echocardiogram at the time of the arterial switch operation, but there was no echocardiographic or clinical evidence of coarctation of the aorta.
Analytical and experimental study of a skew bridge model

This paper describes an experimental study of a skew bridge model conducted at the Federal Highway Administration Turner-Fairbank Highway Research Center. The objectives of the experiment are: (1) to perform a pilot study on the design, construction, instrumentation, testing and data processing of a skew bridge model, (2) to provide experimental data to validate a 3D finite element model developed for the skew bridge, and (3) to confirm the applicability of a simplified bridge model (the dual-beam stick model) developed for the dynamic analysis of skew bridges. Details of the design, construction, instrumentation, testing and data processing of the model bridge are described. Results for static displacements, natural frequencies, mode shapes and damping of the model bridge will be presented. A comparison of the results obtained from these tests with those obtained numerically from a finite element analysis and analytically from the dual stick bridge model shows that good correlation is obtained.
Female attractiveness and eating disorders: Do children's television commercials play a role?

The differential rate of eating disorders in males and females has been partially attributed to gender socialization. Media influences, even in children's programming, may contribute to the greater emphasis on physical attractiveness for girls compared to boys. Commercials from Saturday morning cartoon programming were analyzed for the number of male/female main and supporting characters, sex of narrator, sex of intended consumer, and appearance enhancement of person, doll, or animal. A majority of the commercials (60.6%) were for food products. Chi-square comparisons revealed significantly more male than female main characters and narrators in these commercials. Of those commercials (13.8%) scored for appearance enhancement, all male/female chi-square comparisons were significant with more female supporting characters, female main characters, female narrators, and female consumers. With the combined emphases on food and, for girls, on appearance, support for possible influences of commercials in eating disorders is noted.
Loss of heterozygosity on chromosomes 17 and 18 in breast carcinoma: two additional regions identified.

Abstract The loss of heterozygosity (LOH) at specific regions of the human genome in tumor DNA is recognized as evidence for a tumor-suppressor gene located within the corresponding region of the homologous chromosome. Restriction fragment length polymorphism analysis of a panel of primary human breast tumor DNAs has led to the identification of two additional regions on chromosomes 17q and 18q that frequently are affected by LOH. Deletions of each of these regions have a significant correlation with clinical parameters that are associated with aggressive breast carcinomas. Previous restriction fragment length polymorphism analysis of this panel of tumors has uncovered several other frequently occurring mutations. LOH on chromosome 18q frequently occurs in tumors with concomitant LOH of loci on chromosomes 17p and 11p. Similarly, tumors having LOH on 17q also have LOH on chromosomes 1p and 3p. This suggests that certain combinations of mutations may collaborate in the development and malignant progression of breast carcinomas.
LU-SGS implicit algorithm for three-dimensional incompressible Navier-Stokes equations with source term

A numerical method is developed for solving the incompressible Navier-Stokes equations using the concept of pseudocompressibility. A lower-upper symmetric-Gauss-Seidel implicit scheme is developed for three-dimensional incompressible viscous flow computations. The present algorithm offers additional advantages when solving the flow equations with source terms. Complete vectorizability of the algorithm on oblique planes of sweep in three-dimensions is accomplished in a new flow solver, INS3D-LU code. Spatial differencing is a second-order accurate semi-discrete finite-volume method augmented by a third-order accurate numerical dissipation model which is based on spectral-radii. Comparison of numerical solutions for a curved duct with experimental data shows good agreement. The method is applied to calculate the inducer flow of the Space Shuttle Main Engine turbopump.
Step Geometry and Countercurrent Effects in Dump Combustor: Reacting Flow

In this article we report a numerical investigation of reacting flow in dump combustors with counterflow and modified step geometry. The flow is simulated by solving Reynolds-averaged Navier-Stokes equations in the framework of the realizable κ–∊ turbulence model. A two-layer approach is used for the near-wall treatment, whereas a one-equation model is employed for the viscous sublayer. The closure for the reaction source term is based on the eddy dissipation concept. The article includes a study of the effect of reaction on the base flow, the effect of countercurrent on the flame, and finally, the role of step geometry. Application of countercurrent results in a thicker averaged flame surface, which leads to an overall increase in the heat release within the combustor. The effect of alteration of the step geometry is found to be much more complicated. At low levels of counterflow there is an increase in turbulence intensity with an increase of the step angle but little change in heat release.
AIDER (Angle-of-Incidence Derivative Ellipsometry and Reflectometry) — Implementation and application

Abstract An experimental arrangement is described whereby spectroscopic polarization-modulation ellipsometry can be extended to the measurement of both the usual parameters ψ and Δ and the derivatives with respect to the angle of incidence, ∂ψ ∂θ and ∂Δ ∂θ . Reflectance measurements can also be made, giving R and ∂(ln R) ∂θ . Expressions are given for the second-derivative quantities ∂ 2 ψ ∂n∂θ , etc. that are used in an iterative solution of the Fresnel relations. The system is used in a reexamination of the color-center layer formed on the surface of KCI during vacuum-ultraviolet irradiation in ultrahigh vacuum. It is found that only F-centers are present in the damage-layer, with no evidence for aggregate centers (i.e., M-centers). The AIDER data indicate a layer thickness of about 75 A.
Structure and DNA Hybridization Properties of Mixed Nucleic Acid/Maleimide−Ethylene Glycol Monolayers

The surface structure and DNA hybridization performance of thiolated single-strand DNA (HS-ssDNA) covalently attached to a maleimide−ethylene glycol disulfide (MEG) monolayer on gold have been investigated. Monolayer immobilization chemistry and surface coverage of reactive ssDNA probes were studied by X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry. Orientation of the ssDNA probes was determined by near-edge X-ray absorption fine structure (NEXAFS). Target DNA hybridization on the DNA−MEG probe surfaces was measured by surface plasmon resonance (SPR) to demonstrate the utility of these probe surfaces for detection of DNA targets from both purified target DNA samples and complex biological mixtures such as blood serum. Data from complementary techniques showed that immobilized ssDNA density is strongly dependent on the spotted bulk DNA concentration and buffer ionic strength. Variation of the immobilized ssDNA density had a profound influence on the DNA probe orientatio...
The Thermochemistry of 2,4-Pentanedione Revisited: Observance of a Nonzero Enthalpy of Mixing between Tautomers and Its Effects on Enthalpies of Formation

The enthalpies of formation of pure liquid and gas-phase (Z)-4-hydroxy-3-penten-2-one and 2,4-pentanedione are examined in the light of some more recent NMR studies on the enthalpy differences between gas-phase enthalpies of the two tautomers. Correlation gas chromatography experiments are used to evaluate the vaporization enthalpies of the pure tautomers. Values of (51.2 ( 2.2) and (50.8 ( 0.6) kJ‚mol -1 are measured for pure 2,4-pentanedione and (Z)-4-hydroxy-3-penten-2-one, respectively. The value of (50.8 ( 0.6) kJ‚mol -1 can be contrasted to a value of (43.2 ( 0.2) kJ‚mol -1 calculated for pure (Z)-4-hydroxy-3-penten-2-one when the vaporization enthalpy is measured in a mixture of tautomers. The difference is attributed to an endothermic enthalpy of mixing that destabilizes the mixture relative to the pure components. Calculation of new enthalpies of formation for (Z)-3-hydroxy-3-penten-2-one and 2,4-pentanedione in both the gas, ¢fH°m(g) ) (-378.2 ( 1.2) and (-358.9 ( 2.5) kJ‚mol -1 , respectively, and liquid phases, ¢fH°m(l) ) (-429.0 ( 1.0) and (-410.1 ( 1.2) kJ‚mol -1 , respectively, results in enthalpy differences between the two tautomers both in the liquid and gas phases that are identical within experimental error, and in excellent agreement with recent gas-phase NMR studies.
Average-case completeness of a word problem for groups

This paper presents a bounded word problem for groups whose random instances are hard on average. The problem is to decide, when given a finitely presented group G, words ~, y, z, and an integer k, whether (Z–lyZ)Z can be obtained from Z(x–l yz) in G using elementary Tietze transformations for at most k times. We show that the problem is average-case NP-complete when instances are chosen at random under a uniform distribution. NP-completeness of more general bounded word problems for groups is shown as well.
Do Type A men drink more frequently than Type B men? Findings in the Multiple Risk Factor Intervention Trial (MRFIT)

The association between the Type A behavior pattern and self-reported alcohol intake was studied among men at high risk for coronary disease in the Multiple Risk Factor Intervention Trial. Two assessments of behavior pattern, the Structured Behavior Pattern Interview (SBPI) and the Jenkins Activity Survey (JAS), and two measures of alcohol intake were examined. Type A's consumed more alcohol (up to 30% more) than Type B's. Type A's drank more frequently than Type B's rather than more alcohol per occasion. This association was consistent for both SBPI and JAS assessments of behavior pattern and was independent of age, income, smoking, and marital status. Increased drinking frequency appears to be a concomitant of the Type A behavior pattern.
High‐Resolution Proton Magnetic Resonance Analysis of Human Cerebrospinal Fluid

High-resolution proton magnetic resonance spectroscopy was used to analyze human cerebrospinal fluid obtained from patients with several neurological problems. The major metabolites measured included glucose, lactate, glutamine, citrate, inositol, acetate, creatine, creatinine, beta-hydroxybutyrate, alanine, and pyruvate. A drug vehicle, propylene glycol, was also measured. Alterations in the cerebrospinal fluid of these metabolites provided information concerning metabolism of the brain. Magnetic resonance spectroscopy offered a simple and rapid means of assessing these and other exogenous and endogenous compounds in diseases affecting the nervous system.
Serogrouping of Neisseria gonorrhoeae: Identification of Four Immunologically Distinct Acidic Polysaccharides

A series of population-specific acidic polysaccharides have been described that can be used as a basis for serogrouping of Neisseria gonorrhoeae. These polysaccharides have been designated Gc antigens, and four immunologically distinct types have been identified. With these purified serogroup antigens and appropriately absorbed antisera in hemagglutination-inhibition systems, four typing systems have been established. Their sensitivities for purified homologous antigens range from 16 to 1 mug/ml. Purified heterologus antigens fail to inhibit at concentrations of 1,000 mug/ml. Clinically isolated N. gonorrhoeae are incorporated into these systems by conversion to standardized crude Gc antigen extracts by alkaline hhydrolysis. Of the 163 strains studied, 83% could be typed; 85% of these were typed for only one serogroup. Twenty strains were typed for two serogroups, and reisolation studies demonstrated that these strains were mosaics rather than mixed cultures. Four strains from each serogroup were selected, and antisera and purified serogroup antigens were produced from them. These were identical with their respective standard serogroup antigen and antisera in hemagglutination-inhibition and immunodiffusion systems.
Pattern recognition and interpretation of electromyogram data from cat jaw muscle

This study investigates the effect of emotional behavior on the masseteric muscle EMG response patterns. Two experimental protocols are utilized: (1) does not elicit emotional behavior (stick chewing) and (2) elicits emotional behavior (hypothalamic stimulation). The Karhunen-Loeve transform is used to compute features which exactly represent the correlated patterns of mean-zero observations, with data compression and noise immunity. Using nonparametric tests, it is found that the populations of biting and hissing features are significantly different (p < 0.05), with increased statistical significance as the size of the training set is increased. No statistically significant difference is seen in a test of the two biting populations.
Molecular cloning and characterization of the promoter of mouse heme-regulated eIF2α kinase

Abstract The heme-regulated eIF2α kinase (HRI) phosphorylates the α subunit of the translation initiation factor 2, which plays an important role in translational regulation during heme deficiency. HRI is expressed mainly in erythroid cells. To elucidate the mechanisms that regulate the tissue-specific expression of the mouse HRI gene, we have cloned and characterized its 5′ flanking region. Primer extension and 5′ RACE analyses identified a major transcription initiation site 84 nucleotides upstream from the ATG start codon. Sequence analysis of the 5′ flanking region revealed that HRI promoter lacked a TATA element, but contained an initiator core element and three SP1 consensus binding motifs. Transient transfection analysis using luciferase reporter gene constructs containing a series of deletions and mutations in the 5′ region identified a 159 bp sequence which is necessary and sufficient for basal HRI promoter activities in NIH 3T3 and mouse erythroleukemic cells. Both the initiator and one of the SP1 binding sites in the 159 bp are essential for HRI promoter activity.
Short report: prospective, randomized trial comparing a single dose sodium phosphate regimen with PEG–electrolyte lavage for colonoscopy preparation

We performed a prospective, randomized trial in 52 patients to see how preparation with a single-dose sodium phosphate solution regimen (Fleet Phospho-Soda), in which the entire 89 ml dose was given on the evening prior to colonoscopy, compared with conventional polyethylene glycol(PEG)-electrolyte lavage in terms of quality of colon cleansing and ease of patient preparation. Previous trials had utilized a two-dose sodium phosphate regimen in which one dose was given on the evening prior to colonoscopy and the other on the morning of the procedure. A nurse gave a questionnaire to the patient prior to colonoscopy, assessing how well the preparation was tolerated. The attending gastroenterologist graded the quality of colon cleansing, unaware of how the patient was prepared or tolerated the preparation (1 = excellent, 2 = good, 3 = fair, 4 = unsatisfactory). Both preparations were similarly tolerated. The overall quality of bowel preparation with PEG lavage was significantly better (mean score 1.62) than with the single-dose sodium phosphate regimen (mean score 2.85) (P = 0.0002). Of 26 patients, 2 (7.7%) undergoing preparation with PEG lavage were judged to have had an unsatisfactory preparation, compared with 8 of 26 patients (30.8%) receiving the sodium phosphate regimen (P = 0.075). We conclude that the single-dose sodium phosphate regimen is suboptimal for clinical practice and its use cannot be recommended.
The inhibition of lens-inducing capacity of the optic vesicle with adult lens antisera.

Abstract 1. 1. Optic vesicles removed, free of ectoderm, from chick embryos of 4–7 somites were explanted for 18 hours in a medium containing a 1:20 dilution of the globulin fraction of anti-adult lens sera. The vesicles were then enclosed in competent ectoderm and cultured 3–4 days in a medium free of the antisera. Induction of a lens occurred in 2 of 61 cases (3%). 2. 2. Induction of a lens resulted in 35 of 66 cases (53%) in the control vesicles cultured in a 1:20 dilution of normal rabbit sera (globulin fraction) and subsequently enclosed in ectoderm. 3. 3. The results of experiments in which optic vesicles were cultured in media containing either antilens sera or normal rabbit sera and subsequently implanted beneath the ectoderm of 4–7 somite embryos conform to the results of the in vitro experiments. 4. 4. A 1:20 dilution of the anti-adult lens sera failed to inhibit development of the otic vesicle. 5. 5. Sections of selected stages of normal embryos were stained with antilens sera conjugated with fluorescein isocyanate. Results indicate a reaction of substances within the optic vesicle with the fluorescein conjugated lens antisera prior to lens induction. 6. 6. The inhibition of the lens-inducing capacity of the optic vesicle by the anti-adult lens sera suggests that substances within the optic vesicle, which can react with adult lens antibodies, are essential in the inductive process.
Neurophysiologic Assessment of Auditory Brain Maturation and Learning in Extremely Premature Infants † 1291

Extremely preterm infants are at risk for cognitive morbidity. Abnormal development of auditory brain pathways may contribute to later auditory processing defects, language delays, or learning disabilities. The purpose of this study was to evaluate developing cognitive pathways in 28 extremely preterm infants (< 29 weeks) compared with 34 healthy control infants using event related potentials (ERPs), an electrophysiologic technique used to test regional maturation of the brain. All infants had normal hearing. Auditory ERPs were obtained during active sleep at 36, 40, and 44 weeks postmenstrual age. Two paradigms were used for all tests. First, to evaluate regional brain maturation, stimuli were a speech sound and a non-speech sound. Second, to evaluate auditory recognition memory, stimuli were voice recordings of the subject's mother and a stranger. For each paradigm, stimuli were alternately presented for a total of 100 trials while brain activity was recorded over midline and lateral electode sites for 2000 msec. Artifact-free trials were cross averaged by stimulus. Averages were analyzed by integrating the area under the curve. For the ERPs elicited by the non-speech sound, a maturational score from 1-5 was assigned (Kurtzberg). Areas were compared for the mother/stranger ERPs using ANOVA. Control infants' ERP patterns were used to evaluate preterm infants' responses. (Study infant's ERP responses will be correlated with language development in follow-up).
Omissions and Causalism

Omissions are puzzling, so puzzling that people tend to say puzzling things about them and give up otherwise attractive philosophical theories in order to accommodate them.1 In this paper I suggest that omissions make trouble—serious trouble, and trouble of a new, sui generis kind—for “causalism,” the standard view or family of views of agency. In particular, I am interested in causalism as an attempt to explain what it is for an agent to behave intentionally. I will argue that causalism cannot accommodate intentional omissions—or, at least, it cannot account for them in the same way it accounts for (positive) actions. As a result, causalism is incomplete—or, at best, highly disjunctive—as a theory of what it is to behave intentionally. I will bypass the question whether omissions can be, properly speaking, actions—“negative actions” or “active nondoings,” as they have been called (see, e.g., Kleinig 1976). For some people (notably, Thomson 1977), actions are a subclass of events, where events are particulars with specific spatiotemporal locations, intrinsic properties, etc. On this kind of view, it’s hard to count omissions as actions, for omissions don’t appear to have specific spatiotemporal locations, intrinsic properties, etc. Nevertheless, even if omissions aren’t actions, it seems that agents can still fail to do things intentionally, and it makes sense to ask under what conditions an agent’s not doing something is intentional (see, e.g., Ginet 2004). Thus, even if omissions aren’t actions, a theory of what it is to behave intentionally should be able to accommodate omissions. (Note that, if omissions aren’t actions, a theory of what it is to behave intentionally is not the same thing as a theory of what it is to perform an intentional action, and it might not even be the same thing as a theory of what it is to act intentionally.)2
Art, Fame, and Commerce

In Praise of Commercial Culture. By Tyler Cowen (Cambridge: Harvard University Press, 2000), ix + 278 pp. $14.95 paper. What Price Fame? By Tyler Cowen (Cambridge: Harvard University Press, 2000), 248 pp. $22.00 cloth.