cssi/SciSciGPT-SciSciNet huggingface dataset:
Single-detector helical CT in PET-CT: assessment of image quality.

OBJECTIVE. CT in positron emission tomography (PET)–CT imaging is often performed as a single scan from the base of the skull to the groin, potentially resulting in degradation of the quality of CT scans depending on the position of the patient's arms and mode of breathing and the use and timing of IV contrast injection. The aim of our study was to assess the impact of artifacts on the diagnostic quality of CT scans using a single-detector helical CT scanner in PET–CT imaging.MATERIALS AND METHODS. Two radiologists retrospectively evaluated the diagnostic image quality of CT scans obtained with PET–CT in 81 patients with lymphoma. The severity of the artifacts related to the position of the patient's arms beside the body, the influence of breathing motion, and the presence of contrast material in the upper thoracic veins were ranked using a 4-point scale.RESULTS. Performing CT with the patient's arms positioned beside the body resulted in streak artifacts, predominantly in the upper abdomen, that were gra...
Dentate gyrus granule cells and memory: electrical stimulation disrupts memory for places rewarded.

Nineteen male albino rats were trained to perform a memory task (“win—stay; delayed matching to sample”) in a radial eight-arm maze. On Trial 1, animals were required to locate food present in only one maze arm and, after a 1-min delay, learned to return directly to the single baited arm on Trial 2. Animals were also trained on a five-trial version, in which three additional trials with interposed 1-min delays were used. Following training, animals were implanted with a single chronic electrode using electrophysiological guidance. In this way, electrodes could be placed directly into the granule cell layer of the dentate gyrus. Thirty seconds of granule cell stimulation administered during the delay period between Trials 3 and 4 of the memory task produced a severe, but reversible, disruption of Trial 4 performance similar to the “working memory” deficits observed after hippocampal lesions.
Sidewall Adhesion and Sliding Contact Behavior of Polycrystalline Silicon Microdevices Operated in High Vacuum

The reliability and performance of contact-mode microelectromechanical systems (MEMS) depend strongly on the tribological properties of contact interfaces. Knowledge of the dominant friction and wear mechanisms at submicrometer length scales is therefore of paramount importance to the design of MEMS devices with contact interfaces. The objective of this study was to examine changes in the adhesion behavior and morphology of sliding sidewall surfaces of polycrystalline silicon MEMS devices operated in high vacuum (~105 torr) and under low apparent contact pressures (0.1-18 kPa) and correlate these changes to the operation lifetime. Sidewall adhesion increased with applied contact pressure. Typically, a twofold to fourfold increase in side wall adhesion was measured upon cessation of the device operation (typically, ~106 sliding cycles) due to the increase of the static friction force above the restoring force available by the device. Scanning electron microscopy (SEM) revealed very small amounts of ultrafine wear debris (10-140 nm) on the sidewall surfaces of about half of the tested devices, without discernible changes in the surface topography. Cross-sectional transmission electron microscopy (TEM) showed that sliding did not cause the removal of the silicon oxide film (5-13 nm in average thickness) from the sidewall surfaces. Atomic force microscopy (AFM) indicated that sliding contact was confined at the top of a few elevated ridges on the sidewall surfaces, resulting in nanoscale wear that smoothened locally the surfaces. SEM, TEM, and AFM results of this study show that the tribological properties of contact-mode MEMS devices operating in high vacuum are controlled by only a few nanoscopic contacts, which depend on the local nanotopography of the interacting surfaces.
Measurement of immunoreactive interleukin-1β from human mononuclear cells: Optimization of recovery, intrasubject consistency, and comparison with interleukin-1α and tumor necrosis factor

Numerous studies have reported altered levels of in vitro production of the cytokines interleukin-1 (IL-1) and tumor necrosis factor (TNF) from blood leukocytes in various human disease states. Most of these studies have used bioassays which are vulnerable to inhibitors produced by these cells. Furthermore in vitro cytokine production is often assessed on a single occasion. The present study was designed to standardize stimulation conditions for in vitro IL-1 beta production and to employ a competitive radioimmunoassay (RIA) to demonstrate reproducibility and long-term variation of in vitro cytokine production in a cohort of healthy human subjects. We also examined relative amounts of immunoreactive IL-1 beta, IL-1 alpha, and TNF induced by the stimuli endotoxin, phytohemagglutinin, or Staphylococcus epidermidis. We show that the RIA can reliably detect IL-1 beta produced from mononuclear cells in concentrations as low as 115 pg/ml. Lysing cells by repeated freeze-thawing yields maximal recovery of total (i.e., secreted plus cell-associated) immunoreactive IL-1 beta, when compared to extraction with the detergent CHAPS or addition of protease inhibitors. Repeated measurement of in vitro cytokine production on different days within 1 week shows good reproducibility for a given individual and a given stimulus (variation coefficient 20 to 30%). Over a long time period (6 months) in vitro cytokine production is stable in some individuals but changes considerably in others. The soluble stimulus endotoxin induces twofold more IL-1 alpha than IL-1 beta or TNF; in contrast the phagocytic stimulus heat-killed S. epidermidis induces fourfold more IL-1 beta and TNF than IL-1 alpha. This distinct pattern of cytokine response indicates differential stimulation of the mononuclear cells by different stimuli. The results form the basis for studying in vitro cytokine production in different human disease states.
Quantitative whole body biodistribution of fluorescent-labeled agents by non-invasive tomographic imaging.

When small molecules or proteins are injected into live animals, their physical and chemical properties will significantly affect pharmacokinetics, tissue penetration, and the ultimate routes of metabolism and clearance. Fluorescence molecular tomography (FMT) offers the ability to non-invasively image and quantify temporal changes in fluorescence throughout the major organ systems of living animals, in a manner analogous to traditional approaches with radiolabeled agents. This approach is best used with biotherapeutics (therapeutic antibodies, or other large proteins) or large-scaffold drug-delivery vectors, that are minimally affected by low-level fluorophore conjugation. Application to small molecule drugs should take into account the significant impact of fluorophore labeling on size and physicochemical properties, however, the presents studies show that this technique is readily applied to small molecule agents developed for far-red (FR) or near infrared (NIR) imaging. Quantification by non-invasive FMT correlated well with both fluorescence from tissue homogenates as well as with planar (2D) fluorescence reflectance imaging of excised intact organs (r2 = 0.996 and 0.969, respectively). Dynamic FMT imaging (multiple times from 0 to 24 h) performed in live mice after the injection of four different FR/NIR-labeled agents, including immunoglobulin, 20–50 nm nanoparticles, a large vascular imaging agent, and a small molecule integrin antagonist, showed clear differences in the percentage of injected dose per gram of tissue (%ID/g) in liver, kidney, and bladder signal. Nanoparticles and IgG1 favored liver over kidney signal, the small molecule integrin-binding agent favored rapid kidney and bladder clearance, and the vascular agent, showed both liver and kidney clearance. Further assessment of the volume of distribution of these agents by fluorescent volume added information regarding their biodistribution and highlighted the relatively poor extravasation into tissue by IgG1. These studies demonstrate the ability of quantitative FMT imaging of FR/NIR agents to non-invasively visualize and quantify the biodistribution of different agents over time.
Differential conditioning and contrast effects in humans

The present study investigated discrimination S+ contrast effects as a function of the magnitude of reward in S- while attempting to alleviate ceiling effect and decision time problems present in previous animal and human simultaneous contrast studies. In the study, three groups of human Ss recrived differential reward conditioning for accurately tracing numbered-nonnumbered star patterns, whereas a control group received only large reward in both discriminanda. The results replicated the findings of a previous animal study which also attempted to control for ceiling and decision time variables in that a positive S+ contrast effect was found. Also, the positive S+ contrast effect increased as the magnitude of reward in S- decreased. The results seem to support a perceptual analysis of contrast effects.
Ray interpretation of the material signature in the acoustic microscope

The output voltage of the reflection acoustic microscope depends on the location on the object surface in a way that is characteristic of its elastic properties. We present a ray model showing that this dependence is due to interference between a narrow bundle of axial rays and rays associated with the leaky Rayleigh wave excited on the surface.
Panoramic imaging of the temporomandibular joint: an experimental study using cadaveric skulls.

Objective The purpose of this study was to determine if condylar morphology can be accurately depicted on the panoramic radiograph and if variations in condylar anatomy affect the radiographic appearance of the condyle. Study Design The shape and angulation of the condyle were determined on 8 cadaveric human skulls. Lead foil markers were then placed on the articulating surface and lateral and medial pole of each condyle. A panoramic radiograph was made of each skull and the position of the markers was assessed. Results The true shape of the condyles was not recognizable on any of the panoramic images. The exact location of the articulating surface and medial and lateral poles could not be predicted on the panoramic images without markers. The location of these structures varied depending on the amount of condylar angulation. Conclusion Because of the radiographic variations produced by differences in condylar angulation, it is not possible to accurately determine condylar morphology on the panoramic radiograph. Therefore, its value in providing the detailed information needed to guide diagnosis and treatment of the temporomandibular joint patient is limited.
Forced migration in Iran during the seventeenth and eighteenth centuries

(1975). Forced migration in Iran during the seventeenth and eighteenth centuries. Iranian Studies: Vol. 8, No. 4, pp. 199-215.
TGF-β signaling in cancer – a double-edged sword

Transforming growth factor (TGF) β1 is a potent growth inhibitor, with tumor-suppressing activity. Cancers are often refractile to this growth inhibition either because of genetic loss of TGF-β signaling components or, more commonly, because of downstream perturbation of the signaling pathway, such as by Ras activation. Carcinomas often secrete excess TGF-β1 and respond to it by enhanced invasion and metastasis. Therapeutic approaches should aim to inhibit the TGF-β-induced invasive phenotype, but also to retain its growth-inhibitory and apoptosis-inducing effects.
Distribution and temperature adaptation in the teleost fish genus Gibbonsia

Along the California coast there are three intertidal species of the genus Gibbonsia (G. elegans, G. metzi, G. montereyensis). These species have distinct but overlapping distributions. Collections were made seasonally from three areas. Each collection was divided into two groups — a critical thermal maximum and minimum were determined for one group and the other group was tested after a 3 week acclimation period. The three species showed genetically different adaptation abilities and these were correlated with species differences in latitudinal distributions. The species that experiences the widest seasonal temperature range proved capable of anticipatory adjustment to temperature while the two experiencing small seasonal changes showed only reactive adjustments. the species with the widest distribution showed the greatest ability to adapt to temperature extremes. After 1 week acclimation all three species demonstrated different mechanisms for heat and cold adaptation.
The American Educational Industrial Complex: A Critique of a Concept Submitted to the Journal of School Choice

Many people view subgovernments such as the “military-industrial complex” as largely self-governing and budget maximizing. Yet, as defense cutbacks in the 1970s and 1990s show, such networks do not maintain their privileged status indefinitely. In similar fashion, some claim public education is too autonomous and too focused on budget maximization. Others see U.S. public education bureaucracies as open systems representing their political environments, if not individual parents. This article seeks clarity by offering a preliminary definition of educational industrial complex and an exploration of its nature and size. The authors summarize the existing literature and present resource measures tracking educational industrial complex growth over time. While per-pupil expenditures have steadily increased, since World War II the increases have largely reflected gross domestic product growth. Further, while the public education student-to-staff ratio initially rose in a Parkinsonian manner, since the Reagan era...
Split identity: Intransitive judgments of the identity of objects

Identity is a transitive relation, according to all standard accounts. Necessarily, if x=y and y=z, then x=z. However, people sometimes say that two objects, x and z, are the same as a third, y, even when x and z have different properties (thus, x=y and y=z, but x≠z). In the present experiments, participants read stories about an iceberg that breaks into two icebergs, one to the east and the other to the west. Many participants (32-54%, in baseline conditions across experiments) decided that both successors were the original iceberg, despite the different spatial locations of the successors. Experiment 1 shows that this tendency is not due to participants failing to understand both to mean both are simultaneously the original. Similarly, Experiment 2 demonstrates that the tendency is not solely due to their interpreting the question to be about properties of the icebergs rather than about the icebergs themselves. Experiments 3 and 4 suggest, instead, that participants may understand Which is the original? to mean Which, in its own right, is entitled to be the original? Emphasizing entitlement increases the number of seemingly intransitive responses, whereas emphasizing the formal properties of identity decreases them.
The main sequence, a tool for studying human eye movements

Abstract The astronomical term “main sequence” has been applied to the relationships between duration, peak velocity, and magnitude of human saccades over a thousandfold range of magnitude. Infrared photodiodes aimed at the iris-sclera border and a digital computer were used in experiments to derive the main sequence curves. In the pulse width modulation model, the duration of the controller signal pulse determines saccadic amplitude and peak velocity. The high-frequency burst of the oculomotoneurons needs to be only one-half the duration of the saccade, because of the “apparent inertia” of the eyeball.
Multiagent Navigation Functions Revisited

This paper presents a methodology to design a control law that can provably steer a group of mobile agents to a free-floating formation of specific shape, while avoiding collisions. We indicate why existing multiagent solutions have a theoretical limitation due to one of the working assumptions of the single-agent potential function approach being violated. A new nonsmooth type of multiagent potential functions is, thus, developed. It is shown how this extension of the navigation function concept to multiagent systems ensures the nondegeneracy of the critical points of the potential function.
MAPS: A Planning System for International Market Entry

This paper describes an international marketing expert system that helps managers make strategic decisions regarding market entry. The system is called MAPS, for MArket-entry Planning System. MAPS is being developed using a combination of AI knowledge representations (i.e. rules, semantic networks, text-analysis techniques) and multi-attribute decision models based on weighted linear algebraic formulas for judgment and evaluation. Previous research by the author and colleagues resulted in several components of MAPS, developed largely as stand-alone products. These components were developed using a shell called CEVAL (Candidate Evaluator). CEVAL and other AI tools are currently being used to integrate the components into a comprehensive system that addresses most of the major issues facing international market planners. This system serves both an educational and a decision-support purpose. © 1996 Wiley Periodicals, Inc.
Consciousness, evolution, and spiritual growth: A critique and model

This essay concerns the question of whether evolutionary theories provide a useful approach to understanding the highest potentials of human consciousness and spiritual growth. Finding one‐dimensional models overly simplistic, we have proposed a three‐level model in which “states of mind” (level 1), “states of consciousness” (level 2), and “structures of consciousness” (level 3) share a hierarchical relationship. States of consciousness (waking states, dream states, etc.) contextualize various states of mind (e.g., sadness, joy, anticipation), and structures of consciousness (mythical, magical, etc.) contextualize states of consciousness. Our model draws upon the grand evolutionary synthesis, a phrase used in some approaches to systems inquiry and complexity theory, and utilizes chaos theory terminology as well, rather than other evolutionary concepts (e.g., biological evolution or historical evolution).
Optical modeling toward optimizing monitoring of intestinal perfusion in trauma patients

Trauma is the number one cause of death for people between the ages 1 and 44 years in the United States. In addition, according to the Centers of Disease Control and Prevention, injury results in over 31 million emergency department visits annually. Minimizing the resuscitation period in major abdominal injuries increases survival rates by correcting impaired tissue oxygen delivery. Optimization of resuscitation requires a monitoring method to determine sufficient tissue oxygenation. Oxygenation can be assessed by determining the adequacy of tissue perfusion. In this work, we present the design of a wireless perfusion and oxygenation sensor based on photoplethysmography. Through optical modeling, the benefit of using the visible wavelengths 470, 525 and 590nm (around the 525nm hemoglobin isobestic point) for intestinal perfusion monitoring is compared to the typical near infrared (NIR) wavelengths (805nm isobestic point) used in such sensors. Specifically, NIR wavelengths penetrate through the thin intestinal wall (~4mm) leading to high background signals. However, these visible wavelengths have two times shorter penetration depth that the NIR wavelengths. Monte-Carlo simulations show that the transmittance of the three selected wavelengths is lower by 5 orders of magnitude depending on the perfusion state. Due to the high absorbance of hemoglobin in the visible range, the perfusion signal carried by diffusely reflected light is also enhanced by an order of magnitude while oxygenation signal levels are maintained. In addition, short source-detector separations proved to be beneficial for limiting the probing depth to the thickness of the intestinal wall.
Excitonic Polarons in Molecular Solids

The hard-core property of the Frenkel exciton is explicitly taken into account in the interaction of conduction electrons with a polarizable medium. The excitonic polaron bandwidth is less narrowed than in the boson approximation, does not vanish for infinite coupling, and is temperature independent. One consequence is that at high temperature the polaron motion is not dominated by hopping, but still contains a contribution from band motion.
The orthopaedic management of myelomeningocele

Nearly all patients with spina bifida require orthopaedic surgery during childhood. Scoliosis and kyphosis interfere with wheelchair mobility, neccessitating spinal fusion. Hip dislocation is prevalent in thoracic and upper lumbar level myelomeningocele, yet rarely requires surgery because the presence of a dislocation does not correlate with the ability of the child to walk. Flexion contractures of the hips and knees may interfere with brace fitting in ambulatory patients, and respond to surgical soft tissue release. Clubfoot deformity occurs in 50% of babies with spina bifida, and requires aggressive surgical correction. Muscular imbalance in the foot can produce calcaneus and cavovarus deformaties in distal neurological level patients. Ulceration of the feet results from failure to obtain a platigrade foot position, and when severe, may lead to amputation
Unusual Properties of the Red and Green Luminescence Bands in Ga-rich GaN

We studied photoluminescence (PL) from deep-level defects in GaN grown under Ga-rich conditions at relatively low temperatures (700-800oC) by molecular-beam epitaxy (MBE). The dominant features of PL spectrum are red and green bands peaking respectively at ~1.8 and ~2.35 eV. Both PL bands decay exponentially at low temperatures (15–100 K) after pulsed excitation. The characteristic lifetime for the red band decreases by almost two orders of magnitude from 110 to 2 µs with increasing temperature from 15 to 100 K, while its integrated intensity after each pulse remains nearly unchanged in the same temperature range due to an increase in the peak intensity in the time-resolved PL curve. The lifetime of the green band remained unchanged in this temperature range. We suggest that these PL bands are caused by transitions between excited and ground states of some deep defects rather than transitions involving a shallow donor, conduction or valence bands.
Estimation of gaussian mixtures with rotationally invariant covariance matrices

Homoscedastic and heteroscedastic Gaussian mixtures differ in the constraints placed on the covariance matrices of the mixture components. A new mixture, called herein a strophoscedastic mixture, is defined by a new constraint, This constraint requires the matrices to be identical under orthogonal trans¬formations, where different transformations are allowed for different matrices. It is shown that the M-step of the EM method for estimating the parameters of strophoscedastic mixtures from sample data is explicitly solvable using singular value decompositions. Consequently, the EM-based maximum likelihood estimation algorithm is as easily implemented for strophoscedastic mixtures as it is for homoscedastic and heteroscedastic mixtures. An example of a “noisy” Archimedian spiral is presented.
Analytic continuation and asymptotic behavior in angular momentum of the scattering matrix in potential scattering

A simple proof is given of the fact that the scattering amplitude is a meromorphic function of angular momentum (for Rel ≤ -1/2) and that it vanishes asl → ∞ along any direction such that Rel → ∞.
Gestural impairment and gestural ability in aphasia: A review ☆

Abstract Studies of gestural ability in aphasic subjects have found impairment of gestural expression and comprehension, with a close relationship between severity of aphasia and degree of gestural impairment. A few investigators have correlated gestural ability with specific language functions or subcategories of aphasia. Reading appears to correlate better with gestural recognition than does auditory comprehension. Despite the general findings of gestural impairment in aphasia, successes have been reported with gestural training including artificial language techniques, pantomime, Amerind, and American Sign Language. Future studies of gestural therapy in aphasia should examine specific language deficits in order to identify those aphasic individuals who can benefit from gestural training.
Short note: Exact calculation of Fourier series in nonconforming spectral-element methods

In this note is presented a method, given nodal values on multidimensional nonconforming spectral elements, for calculating global Fourier-series coefficients. This method is ``exact'' in that given the approximation inherent in the spectral-element method (SEM), no further approximation is introduced that exceeds computer round-off error. The method is very useful when the SEM has yielded an adaptive-mesh representation of a spatial function whose global Fourier spectrum must be examined, e.g., in dynamically adaptive fluid-dynamics simulations.
An Object-Oriented Systems Engineering Model Design for Integrating Spent Fuel Extraction and System Processes

The mission of the Transmutation Research Program (TRP) at University of Nevada, Las Vegas (UNLV) is to establish a nuclear engineering test bed that can carry out effective transmutation and advanced reactor research and development effort. UNLV has developed a multi-function software package, TRPSEMPro, to interact with the chemical separation process developed by the Argonne National Laboratories (ANL). As indicated in the Spent Fuel Treatment Facility (SFTF) process requirement, developing a software package system with the capability of optimizing facility process based on the pre-defined objective functions can be valuable for the SFTF. The objective is to further extent the TRPSEMPro framework to integrate chemical separation calculation package AMUSE (Argonne Model for Universal Solvent Extraction) with commercially available system process package (ASPEN-plus). A development concept of middleware is employed to build communication between the AMUSE code and the ASPEN-plus. Since the object-oriented designed ASPEN-plus software package exposes its parameters as well-defined objects, the TRPSEMPro can directly access its variable trees through the object call. Due to the complicity of the system, a scenario-based database system will be developed associated with the chemical separation and system processes. A light-weight MS ACCESS database is selected for easy maintenance and accessibility. The database manages the scenario parameter files with associated separation results and outputs from the system process packages. A comprehensive SFTF process simulation will greatly facilitate the evaluation of overall systems options. Such simulation is gradually becoming important for down-selecting reactor types, fuel types, and multi-recycle modes. Optimization tool associated with the TRPSEMPro system engineering model intends to speedup the possible chemical separation parameters.Copyright © 2005 by ASME
Synthesis and Analysis of Cobalt Ferrite in YSZ for Use as Reactive Material in Solar Thermochemical Water and Carbon Dioxide Splitting

This paper reports the synthesis, characterization and evaluation of different weight loadings of cobalt ferrite (CoFe2O4) in 8 mol% yttria-stabilized zirconia (8YSZ) via the co-precipitation method. Prepared powders were calcined at 1350 °C for 36 hours and 1450 °C for 4 hours in air. These powders were then formed into a porous structure using sacrificial pore formation via oxidation of co-mixed graphite powder. These formed structures obtained were then characterized using thermogravimetric analysis (TGA), X-ray diffraction (XRD), high temperature X-ray diffraction (HT-XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). Brunauer-Emmett-Teller (BET) surface area analysis was performed on the most promising of the structures before being subjected to 50 thermal reduction-CO2 oxidation (redox) cycles using TGA. Together, these results indicate that CoFe2O4-8YSZ can provide a lower reduction temperature, maintain syngas production performance from cycle to cycle, and enhance utilization of the reactive material within the inert support in comparison to iron oxide only structures.Copyright © 2013 by ASME
Technique for jet-thinning aged iron-chromium alloys for TEM☆

Developpement d'une nouvelle solution pour le polissage electrolytique compatible avec les precipites contenus dans l'alliage Fe-40% at. Cr vieilli
The ‘hidden observer’ and ideomotor responding: a real‐simulator comparison

Subjective reports of the amount of effort required to complete an ideomotor (i.e. arm suspension) task were contrasted across baseline, hypnosis, hidden observer and post-session trials among N = 124 participants who had previously scored in the high or low range on a standardized measure of hypnotizability. Low hypnotizable participants received simulation instructions prior to the experiment. Three different instructions were administered during the hidden observer trial. Participants were told that their hidden observer would be: more aware of the effort required to complete the task; or less aware; or they received no specific instruction concerning how their hidden observer report should differ from their previously generated hypnosis report. Results showed that the wording of the instructions influenced hidden observer ratings for both real and simulating participants. Copyright © 2005 British Society of Experimental & Clinical Hypnosis. Published by John Wiley & Sons, Ltd.
Synthesis of a key intermediate for the total synthesis of streptovaricin A

Abstract A key intermediate ( 3 ) for the total synthesis of streptovaricin A ( 1 ) is synthesized in its optically active form. Further elaboration of 3 is also described.
SOURCES FOR THE STUDY OF MEXICAN URBANISM

(1974). SOURCES FOR THE STUDY OF MEXICAN URBANISM. The Professional Geographer: Vol. 26, No. 4, pp. 399-406.
An Acyl-CoA Synthase (acoas) Gene Adjacent to the Mycocerosic Acid Synthase (mas) Locus Is Necessary for Mycocerosyl Lipid Synthesis in Mycobacterium tuberculosisvar. bovis BCG

An open reading frame, ORF3, first identified adjacent to the mycocerosic acid synthase gene in Mycobacterium bovis BCG encodes a protein with acyl-CoA synthase (ACoAS) activity. Genes homologous to acoas are found adjacent to other multifunctional polyketide synthase genes in the mycobacterial genome. To test whether these gene products are necessary to esterify the fatty acids generated by the adjacent polyketide synthase gene products, the acoas gene was disrupted in M. bovis BCG using a suicide vector containing the acoas gene with an internal deletion and the hygromycin-resistant gene as selection marker. Allelic exchange at the acoas locus was confirmed by Southern hybridization and polymerase chain reaction amplification of both flanking regions expected from homologous recombination. Immunoblot analysis indicated that the 65-kDa ACoAS protein product was absent in the mutant. Chromatographic analysis of lipids derived from [1-14C]propionate showed that the mutant did not produce mycocerosyl lipids, although it produced normal levels of mycocerosic acid synthase. These results suggest that ACoAS is involved in the synthesis of mycocerosyl lipids of the mycobacterial cell wall.
Progesterone is not the same as 17α-hydroxyprogesterone caproate: implications for obstetrical practice.

Clinicians1-4 and professional organizations5-7 commenting on the role of progestogens in the prevention of preterm birth have used the term progesterone interchangeably with 17α-hydroxyprogesterone caproate, implying that these two compounds are the same. Yet, there are chemical, biological, and pharmacologic differences between the two.8,9 The clinical indications also differ. This Editorial will review the differences between the two compounds and propose that clinicians and investigators use the abbreviation 17-OHPC (rather than 17P) to refer to 17α-hydroxyprogesterone caproate. The abbreviation 17-OHPC was first recommended by Dr Steven Caritis from the University of Pittsburgh and has been used in the American Journal of Obstetrics and Gynecology by Dr Caritis and his coauthors.
Rapid Screening for the Isolation of Mutants of Aspergillus nidulans with Increased Penicillin Yields

Summary. After UV treatment conidia of a strain of Aspergillus nidulans were plated on an agar medium. The survivors gave rise to individual colonies which were inoculated separately on agar discs and incubated. The discs were then transferred to biological assay plates seeded with spores of a strain of Bacillus subtilis sensitive to penicillin. Using this primary screening method, mutants have been isolated which, when tested later in shake flask cultures, gave larger penicillin yields than the parent strains.
Structural basis of group G streptococcal antigenicity.

Abstract Samples of streptococcal group G antigenic cell-wall polysaccharide extracted by different methods were analyzed for their carbohydrate content and tested for serological reactivity. On the basis of inhibition of group G-specific precipitation by various l -rhamnose derivatives, as well as by methylation analysis of the polysaccharide, it was concluded that the serologically determinant l -rhamnosyl residues were in α-1,4-linkages to the penultimate residues in the G polysaccharide chains. Studies of streptococcal group B precipitation by its homologous antisera, using the same l -rhamnose derivatives as inhibitors, led to the tentative conclusion that its serologically determinant l -rhamnosyl-residues are in α-1,2-linkage with the rhamnose chains in group B polysaccharide. The inhibition of groups B and G precipitation by other streptococcal polysaccharides suggested that cell wall polysaccharides of groups A, A Variant, C, E, and H contain α-1,3-linked terminal rhamnose units; that groups G, F, and K are α-1,4-linked; and that group B polysaccharide is unique among those tested in containing α-1,2-inter-rhamnosyl-linkages.
Determination of an endothelin receptor antagonist in rat plasma by radioimmunoassay.

Abstract A quantitative method based on radioimmunoassay for the determination of an endothelin receptor antagonist (C31H33NO7, I) has been developed and validated. The immunogen was prepared by coupling I to the bovine serum albumin via the N-hydroxysuccinimide ester of I from which the radioligand was also prepared by the reaction with [ 125 I ]-iodotyrosine. The method was specific and no immunoactive material other than the parent drug was detectable in mammalian plasma. This direct assay, using 50 μl of rat plasma is sensitive (0.4 ng/ml), without matrix interference, and has sufficient sensitivity, specificity, accuracy and precision for the analysis of dosed rat plasma samples.
Cation Replacement Studies on Heteroionic Bentonitic Clay Fractions Using Specific Ion Glass Electrodes

Centrifuged fractions, ranging in size from 2·0 to 0·05 µ of a Wyoming bentonite, Bentonita de Durango from Mexico, and Helms clay from Texas were studied. The variation in replacement of Na+, Ca2+, Mg2+, K+, and H+ from these heteroionic clay systems under specific equilibrium conditions of salt concentrations was measured. The displacement cation distribution was monitored by using specific ion glass electrodes, such as a sodium ion electrode, a cationic glass electrode, a calcium ion electrode and a Tektite electrode. Some factors affecting the exchange reactions are discussed and application of findings to drilling and production techniques is indicated.
A Chemical and Genetic Approach to the Mode of Action of Fumagillin

Summary Previous mode of action studies identified methionine aminopeptidase 2 (MetAP-2) as the target of the antiangiogenic natural product fumagillin and its drug candidate analog, TNP-470. We report here that TNP-470-mediated MetAP-2 inhibition blocks noncanonical Wnt signaling, which plays a critical role in development, cell differentiation, and tumorigenesis. Consistent with this finding, antisense MetAP-2 morpholino oligonucleotide injection in zebrafish embryos phenocopies gastrulation defects seen in noncanonical Wnt5 loss-of-function zebrafish mutants. MetAP-2 inhibition or depletion blocks signaling downstream of the Wnt receptor Frizzled, but upstream of Calmodulin-dependent Kinase II, RhoA, and c-Jun N-terminal Kinase. Moreover, we demonstrate that TNP-470 does not block the canonical Wnt/β-catenin pathway. Thus, TNP-470 selectively regulates noncanonical over canonical Wnt signaling and provides a unique means to explore and dissect the biological systems mediated by these pathways.
Using stable oxygen isotopes to quantify the water source used for transpiration by native shrubs in the San Luis Valley, Colorado U.S.A.

An understanding of the water source used by phreatophytic desert shrubs is critical for understanding how they function and respond to man-caused groundwater drawdowns. Shrubs can use primarily groundwater, precipitation recharged soil water, or a mixture of the two. If shrubs use primarily groundwater, a water table decline may reduce water availability and lead to high plant mortality. However, if shrubs can acquire precipitation recharged soil water, then groundwater decline could have less impact on plants. This study took place in the San Luis Valley, a large, arid, high elevation closed basin in south-central Colorado. We examined stable oxygen isotopes in precipitation, soil water from several depths, groundwater and plant xylem water to identify the likely water sources for the three most abundant shrubs in the valley: Sarcobatus vermiculatus (Hooker) Torrey, Chrysothamnus nauseosus (Pallas) Britton subsp. consimilis (Greene) Hall & Clements, and Chrysothamnus greenei (Gray) Greene. C. greenei is not known to be phreatophytic while S. vermiculatus and C. nauseosus may be phreatophytic. Mean annual San Luis Valley precipitation during the two years of study was 121 mm, with 67% occurring during the summer monsoon season of July through September. We found differences in water acquisition patterns by species, season, and along a depth to water table gradient. C. greenei only occurred in sites with a water table > 2.0 m deep, and utilized only soil water recharged by precipitation. At sites with a water table less then 2 m depth, S. vermiculatus and C. nauseosus utilized soil water from the top 0.5 m and shallow groundwater during the pre-monsoon and monsoon periods. A more complex water use pattern was found at sites with a water table deeper then 2 m. S. vermiculatus and C. nauseosus used both deep soil water and groundwater during 1996. During the pre-monsoon period in 1997, both shrubs utilized predominantly groundwater. However, during the 1997 monsoon season both species switched to utilize primarily precipitation recharged water acquired from the upper 0.3–0.4 m of soil. This is the first report that C. nauseosus can utilize summer precipitation. Our results support the hypothesis that plants utilize more summer rain recharged soil water in regions receiving a substantial proportion of annual precipitation during the summer.
Effect of glycine propionyl-L-carnitine on aerobic and anaerobic exercise performance.

The purpose of this study was to evaluate the effect of glycine propionyl-Lcarnitine (GPLC) supplementation and endurance training for 8 wk on aerobicand anaerobic-exercise performance in healthy men and women (age 18–44 yr). Participants were randomly assigned to 1 of 3 groups: placebo (n = 9), 1 g/d GPLC (n = 11), or 3 g/d GPLC (n = 12), in a double-blind fashion. Muscle carnitine (vastus lateralis), VO2peak, exercise time to fatigue, anaerobic threshold, anaerobic power, and total work were measured at baseline and after an 8-wk aerobic-training program. There were no statistical differences (p > .05) between or within the 3 groups for any performance-related variable or muscle carnitine concentrations after 8 wk of supplementation and training. These results suggest that up to 3 g/d GPLC for 8 wk in conjunction with aerobic-exercise training is ineffective for increasing muscle carnitine content and has no significant effects on aerobic- or anaerobic-exercise performance.
The Scottish Philosophy and American Theology

The Scottish Philosophy is no longer in good repute despite its proud reign in another day. Indeed, few, if any, schools of philosophy have been given such disdainful treatment by historians as Common Sense Realism; and few, if any, philosophers have had to suffer such ignominious re-evaluations as Thomas Reid and Dugald Stewart, who were once lionized as the founders of a great and enduring philosophical synthesis. Yet the very decisiveness of this reversal creates at least two challenging problems, one philosophical and the other historical. First, was the Scottish Philosophy as undistinguished as posterity has judged it to be? (To this I would answer with a qualified negative, but the subject is outside the purview of the present essay.) Second, why, when its ultimate rejection was so complete, did the Scottish Philosophy for over a century play such a large and variegated role in Western thought, being in its origins a forceful liberalizing religious movement, in France the near-official “middle-way” of the Restoration and July Monarchy, and in America the handmaiden of both Unitarianism and Orthodoxy? The account which follows is directed to this second question as well as to the factors in Scottish and American intellectual history which demonstrate the importance of asking it.
Evaluating photosynthesis in boreal forest species with fluorescence measurements

The utility of fluorescence measurements in identifying changes in physiological response associated with seasonal change in the photosynthesis process was investigated in several boreal forest species during the summer and fall of 1994, as part of the Boreal Ecosystem-Atmospheres Study (BOREAS) in Saskatchewan, Canada. Four overstory species were examined: jack pine (Pinus banksiana), black spruce (Picea mariana BSP), white spruce (Picea glauca), and quaking aspen (Populus tremuloides). The aspen understory shrub, hazelnut (Corylus americana), was also examined. Stands of different ages, mature and young, were examined for the pine and aspen; the black spruce stand was mature, whereas the white spruce stand was young. For the conifers, needles on the same shoot from separate age classes were evaluated separately, but combined here. Canopy averages were computed from field and laboratory measurements made on shoots or leaves from the upper and lower tree layers of the tree overstory (and hazelnut understory). In situ gas exchange measurements were made in the field. Photosynthetic capacity was determined by oxygen evolution under controlled conditions in a field laboratory. Extracts of leaves/needles were later utilized to determine pigment content from spectral absorption coefficients, and fluorescence emission spectra between 360-780 nm (excitation at 340 nm). A qualitatively different pattern between coniferous and deciduous species was observed in the seasonal shifts in fluorescence: conifers exhibited a general fluorescence decrease in autumn from higher summer values at all wavelengths, whereas the deciduous species exhibited lower (higher) red/far-red (blue) fluorescence in fall. In situ photosynthesis was significantly higher for aspen than its hazelnut understory or the conifers during midsummer. However, photosynthetic capacity determined under controlled laboratory conditions was 4-6 times greater than field values for all species, indicating strong stomatal limitations to ambient gas exchange. A red/blue fluorescence ratio (680 nm/440 nm) was correlated with photosynthetic capacity.
The Effects of Demographic Variables, Ethnic Prejudice, and Attitudes toward Immigration on Opposition to Bilingual Education:

The majority of quantitative research on race relations focuses on Whites’ opposition to policies that are designed to help Blacks. The current study looks beyond this White/ Black model of racism and focuses on opposition to bilingual education. It is hypothesized that demographic variables, prejudice against Latinos, and attitudes toward immigration increase opposition to bilingual education. The results support these hypotheses. It is also found that education has a significant positive relationship with opposition to bilingual education. This result was unexpected and needs to be explored in the future. The positive relationship between prejudice against Latinos and opposition to bilingual education suggests that this is a race issue. However, the significance of attitudes toward immigration suggests that anti-Latino prejudice works differently than prejudice against Blacks. Therefore, future research on race relations should focus on all minority groups to gain an inclusive understanding of racial/et...
HIV/AIDS and Aging: A Diverse Population of Vulnerable Older Adults

Older adults, those age 50 and over, have continually represented approximately 10-15% of all cases of AIDS reported to the Centers for Disease Control and Prevention. In addition to those infected with HIV, many older adult caregivers are affected by HIV/AIDS. Despite these figures, social workers and other providers of health care are often unaware of the needs of these growing populations. Older adults with HIV/AIDS as well as those affected by the disease represent diverse backgrounds in gender, ethnicity, sexual orientation, and exposure to HIV. Additionally, older adults present special issues and challenges not always present in younger individuals with HIV/AIDS.
Granule-bound starch synthase: structure, function, and phylogenetic utility.

*Department of Biological Sciences, University of Idaho; and †Department of Organismic and Evolutionary Biology, HarvardUniversityInterest in the use of low-copy nuclear genes for phylogenetic analyses of plants has grown rapidly, because highlyrepetitive genes such as those commonly used are limited in number. Furthermore, because low-copy genes aresubject to different evolutionary processes than are plastid genes or highly repetitive nuclear markers, they providea valuable source of independent phylogenetic evidence. The gene for granule-bound starch synthase (GBSSI orwaxy) exists in a single copy in nearly all plants examined so far. Our study of GBSSI had three parts: (1) Aminoacid sequences were compared across a broad taxonomic range, including grasses, four dicotyledons, and themicrobial homologs of GBSSI. Inferred structural information was used to aid in the alignment of these verydivergent sequences. The informed alignments highlight amino acids that are conserved across all sequences, anddemonstrate that structural motifs can be highly conserved in spite of marked divergence in amino acid sequence.(2) Maximum-likelihood (ML) analyses were used to examine exon sequence evolution throughout grasses. Differ-ences in probabilities among substitution types and marked among-site rate variation contributed to the observedpattern of variation. Of the parameters examined in our set of likelihood models, the inclusion of among-site ratevariation following a gamma distribution caused the greatest improvement in likelihood score. (3) We performedcladistic parsimony analyses of GBSSI sequences throughout grasses, within tribes, and within genera to examinethe phylogenetic utility of the gene. Introns provide useful information among very closely related species, butquickly become difﬁcult to align among more divergent taxa. Exons are variable enough to provide extensiveresolution within the family, but with low bootstrap support. The combined results of amino acid sequence com-parisons, maximum-likelihood analyses, and phylogenetic studies underscore factors that might affect phylogeneticreconstruction. In this case, accommodation of the variable rate of evolution among sites might be the ﬁrst step inmaximizing the phylogenetic utility of GBSSI.
Understanding The Charismatic Leader-Follower Relationship: Promises and Perils

The authors propose a framework for analyzing the dynamics of the leader-follower relationship in a mentoring context. To illustrate their framework, they use personal disclosure and personal case ...