cssi/SciSciGPT-SciSciNet huggingface dataset:
Evolutionary basis and ecological role of toxic microbial secondary metabolites

Abstract This presentation develops a theory of the evolutionary origin and ecological implications of toxic microbial secondary metabolites. The theory is based on a model system that outlines cause—effect associations between pertinent biotypes in the aflatoxin contamination of developing maize kernels. The model suggests that the aflatoxin-producing fungi are natural digestive tract inhabitants of a number of insect species that feed on developing kernels. During feeding, the insect larvae introduce fungal propagules and provide infection sites on damaged kernels. The fungal association with insects exhibits extraordinary variability, ranging from symbiotic to pathogenic. Elaboration of aflatoxin by the fungus facilitates the pathogenic process in host insects. The theory contends that genetic information for secondary microbial metabolites evolved during ecosystem disequilibria. During periods of ecological stability, mechanisms evolved for repression of toxic secondary metabolite biosynthesis. The theory broadly suggests that contemporary agricultural activities presents the requisite milieu for production or toxic microbial secondary metabolites.
Ail Proteins of Yersinia pestis and Y. pseudotuberculosis Have Different Cell Binding and Invasion Activities

The Yersinia pestis adhesin Ail mediates host cell binding and facilitates delivery of cytotoxic Yop proteins. Ail from Y. pestis and Y. pseudotuberculosis is identical except for one or two amino acids at positions 43 and 126 depending on the Y. pseudotuberculosis strain. Ail from Y. pseudotuberculosis strain YPIII has been reported to lack host cell binding ability, thus we sought to determine which amino acid difference(s) are responsible for the difference in cell adhesion. Y. pseudotuberculosis YPIII Ail expressed in Escherichia coli bound host cells, albeit at ∼50% the capacity of Y. pestis Ail. Y. pestis Ail single mutants, Ail-E43D and Ail-F126V, both have decreased adhesion and invasion in E. coli when compared to wild-type Y. pestis Ail. Y. pseudotuberculosis YPIII Ail also had decreased binding to the Ail substrate fibronectin, relative to Y. pestis Ail in E. coli. When expressed in Y. pestis, there was a 30–50% decrease in adhesion and invasion depending on the substitution. Ail-mediated Yop delivery by both Y. pestis Ail and Y. pseudotuberculosis Ail were similar when expressed in Y. pestis, with only Ail-F126V giving a statistically significant reduction in Yop delivery of 25%. In contrast to results in E. coli and Y. pestis, expression of Ail in Y. pseudotuberculosis led to no measurable adhesion or invasion, suggesting the longer LPS of Y. pseudotuberculosis interferes with Ail cell-binding activity. Thus, host context affects the binding activities of Ail and both Y. pestis and Y. pseudotuberculosis Ail can mediate cell binding, cell invasion and facilitate Yop delivery.
Selective initiation of nonconjugated dienes containing electron donor–electron acceptor systems. II. Polymerization studies of vinyl ether–β‐nitrostyrenes

The monomer series, o-, m-, and p-(2-vinyloxyethoxy)-β-nitrostyrenes, was studied. All three monomers were selectively polymerized through the electron-donating vinyloxy group via cationic initiation. The linear polymers from the meta and para isomers containing the electron-accepting nitrovinyl group were readily crosslinked via anionic initiation. The polymer derived from the ortho isomer was not crosslinked by this mechanism, an observation in accord with results previously reported from these laboratories in which it was shown that all o-substituted-β-nitrostyrenes having ortho substituents larger than fluorine exhibited a sterically inhibited propagation step. The meta and para isomers of this series were selectively polymerized through the electron-accepting nitrovinyl group via anionic initiation. Because of the fact that the resulting polymers were soluble only in highly polar solvents, subsequent crosslinking of these polymers via cationic initiation could not be accomplished. However, these polymers showed strong tendencies to undergo crosslinking upon long exposure to air. Because of the sterically induced ortho effect referred to above, no significant polymerization occurred in the case of the ortho isomer of this series via anionic initiation. However, it was shown in this case that initiation via the anion was rapid, and that the slow step was propagation.
Parent-Professional Partnership in Behavioral Support: A Case Study of Community-Based Intervention.

In this study and a companion article (Fox et al., 1997), we present an investigation that uses multiple research perspectives to study community-based, family-centered behavioral support. This stu...
Influence of leaching solution and catchment location on the fluorescence of water-soluble organic matter.

Organic matter (OM) plays a significant role in biogeochemical processes in soil and water systems. Water-soluble organic matter (WSOM) leached from soil samples is often analyzed as representative of potentially mobile OM. However, there are many WSOM extraction methods in the literature with no clear guidelines for method selection. In this study, four common leaching solutions (0.5 M K2SO4, 0.01 M CaCl2, 2 M KCl, and H2O) were used to extract WSOM from various locations within a forested catchment. Fluorescence spectroscopy was used to analyze the impact of extraction method on WSOM chemistry. While all four methods consistently identified chemical differences between WSOM from a north-facing slope, south-facing slope, and riparian zone, there were clear differences in fluorescence signals between the leaching methods. All three salt solutions contained WSOM with a higher fluorescence index and humification index than WSOM leached with H2O, suggesting the presence of salts releases different fractions ...
Undergraduate Laboratory Module for Implementing ELISA on the High Performance Microfluidic Platform

Implementing enzyme-linked immunosorbent assays (ELISA) in microchannels offers several advantages over its traditional microtiter plate-based format, including a reduced sample volume requirement, shorter incubation period, and greater sensitivity. Moreover, microfluidic ELISA platforms are inexpensive to fabricate and allow integration of analytical procedures, such as sample preconcentration, that further enhance the performance of the immunoassay. In view of the scientific potential of microfluidic ELISAs, inclusion of this technique into an undergraduate curriculum is valuable in preparing the next generation of scientists and engineers. Here, an experimental module is presented for this immunoassay method that can be completed in an undergraduate laboratory setting within two 3-h periods (including all incubation and data analyses procedures) using only a microliter of sample and reagents per assay. In addition to acquainting students with the microfluidic technology, the reported module provides training in quantitating ELISAs using the kinetic format of the assay. Furthermore, it offers a useful educational tool for introducing undergraduates to basic image analysis techniques, as well as signal-to-noise ratio and limit of detection calculations that are valuable in characterizing any analytical method.
Equilibration Procedure to Forecast Areawide Travel

A simple supply/demand equilibrium procedure for urban areawide travel-estimation is presented. The parameters used in this procedure are demand elasticities, trip-making frequency rates, average trip durations, and the valuation of travel time. To make the procedure applicable in a variety of cities, these parameters are given for four city groups stratified according to size and urban structure. This generalized pivot-point procedure is then verified using three case studies, which show that the forecasts made by the approximation procedures are comparable to observed post-implementation traffic counts in one case, and have only small discrepancies when compared with forecasts made by traditional (detailed) methods in the other two cases. Most importantly, the research results are consistent with such theories as a constant travel-time budget, and the temporal and spatial stability of travel parameters. This consistency is in fact the basic building block of the procedure.
Skeletal muscle hemoglobin content measured by near-infrared spectroscopy during oscillatory venous pressure variation

Changes in oxidized (HbO), reduced (Hbr), and total hemoglobin (Hbt) contents were monitored by near infrared spectroscopy in human forearm skeletal muscle during oscillatory variations of the effective venous pressure. Laser diode pulses (wavelength, 775, 810, 865, 904; duration, 60 ns) were directed to the muscle by means of an optic fiber bundle and detected with a sensing fiber positioned at 1.5 cm from the emitting bundle. Sinusoidal pressure waves (frequency, 1 and 2 cycles/min; amplitude, 10-15 mm Hg) generated by a piston pump were transmitted to a sphygmomanometer cuff placed on the arm, the mean cuff pressure (Pc) being 20, 40 and 60 mm Hg. Variations of HbO, Hbr and Hbt were computed from the optical signals and processed by Fourier analysis to characterize their amplitude and phase relative to the cuff mean pressure oscillations (Posc). Oscillations of HbO, Hbr, Hbt were observed for all mean cuff pressures, the amplitude of the variations being decreased with increasing Pc. For Pc equals 20 mm Hg, the oscillations of HbO and Hbt were nearly in phase with Posc whereas the oscillation of Hbr were out of phase with HbO and Posc. Increasing Pc resulted in an increase of the phase difference between HbO and Posc, Hbr remaining out of phase with Posc. These trends could be predicted with a lumped model of the forearm vasculature, suggesting that the technique could be used to asses mechanical characteristics of vascular beds.
An evaluation of selenium concentrations in water, sediment, invertebrates, and fish from the Solomon River Basin

The Solomon River Basin is located in north-central Kansas in an area underlain by marine geologic shales. Selenium is an indigenous constituent of these shales and is readily leached into the surrounding groundwater. Portions of the Basin are irrigated primarily through the pumping of selenium-contaminated groundwater from wells onto fields in agricultural production. Water, sediment, macroinvertebrates, and fish were collected from various sites in the Basin in 1998 and analyzed for selenium. Selenium concentrations were analyzed spatially and temporally and compared to reported selenium toxic effect thresholds for specific ecosystem components: water, sediments, food-chain organisms, and wholebody fish. A selenium aquatic hazard assessment for the Basin was determined based on protocol established by Lemly. Throughout the Basin, water, macroinvertebrate, and whole fish samples exceeded levels suspected of causing reproductive impairment in fish. Population structures of several fish species implied that successful reproduction was occurring; however, the influence of immigration of fish from low-selenium habitats could not be discounted. Site-specific fish reproduction studies are needed to determine the true impact of selenium on fishery resources in the Basin.
Bioconversion of dietary provitamin A carotenoids to vitamin A in humans

Recent progress in the measurement of the bioconversion of dietary provitamin A carotenoids to vitamin A is reviewed in this article. Methods to assess the bioavailability and bioconversion of provitamin A carotenoids have advanced significantly in the past 10 y, specifically through the use of stable isotope methodology, which includes the use of labeled plant foods. The effects of the food matrix on the bioconversion of provitamin A carotenoids to vitamin A, dietary fat effects, and the effect of genotype on the absorption and metabolism of β-carotene have been reported recently. A summary of the major human studies that determined conversion factors for dietary β-carotene to retinol is presented here, and these data show that the conversion efficiency of dietary β-carotene to retinol is in the range of 3.6–28:1 by weight. There is a wide variation in conversion factors reported not only between different studies but also between individuals in a particular study. These findings show that the vitamin A value of individual plant foods rich in provitamin A carotenoids may vary significantly and need further investigation.
High-field magnetic resonance imaging of Wilson's disease

A single case of Wilson's hepatolenticular degeneration was imaged by computed tomography and magnetic resonance (1.5 Tesla). Findings included generalized cerebral atrophy seen both on computed tomography and magnetic resonance images. T1-weighted images revealed a slight symmetric hypointensity in the lentiform nuclei and thalamus. T2-weighted images demonstrated marked symmetric hypointensity in the lentiform nuclei. These hypointensities are ascribed to the deposition of intracellular hemosiderin (and perhaps copper), which produce heterogeneous magnetic susceptibility and preferential T2-proton relaxation. Areas of increased signal activity on T2-weighted images were also seen in areas of presumed demyelination known to occur in Wilson's disease.
Carba-prostacydin inhibits 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced transformation in sensitive murine epidermal JB6 cells

The ability of carba-prostacyclin (cPGI2), a stable analog of prostacyclin (PGI2), to inhibit 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced transformation of JB6 cells was investigated. JB6 cells sensitive (P+) and resistant (P-) to TPA-induced transformation to anchorage-independent growth were plated in soft agar in the presence or absence of cPGI2 for 14-21 days. Transformation frequencies were determined by recording colony numbers. cPGI2 was found to inhibit TPA-induced transformation of P+ cells in a dose-dependent fashion with 1 microM cPGI2 producing approximately 50% inhibition of colonies in soft agar. Our findings are consistent with the hypothesis that TPA-induced transformation in JB6 cell variants is mediated by PGI2 via regulation of adenylate cyclase activity and cAMP accumulation, with resultant inhibition of expression of the transformed phenotype, reflected in anchorage-independent growth.
Isolation of a Pi class glutathione S-transferase (GST) from catfish intestinal mucosa

Abstract Glutathione S-transferases (GSTs) are known to play an important role in the intestinal biotransformation of the epoxide and diol-epoxide metabolites of benzo(a)pyrene formed in catfish intestine (James et al. (1994) The Toxicologist 14, 431). Intestinal mucosal cytosol prepared from the proximal, medial and distal regions had GST activity with 1-chloro-2,4-dinitrobenzene, ethacrynic acid and benzo(a)pyrene-4,5-oxide as substrates. Intestinal GSTs were isolated from dialyzed cytosol by glutathione-agarose affinity chromatography. More than 90% of the intestinal GST activity bound to the glutathione (GSH)-agarose. Elution with GSH gave one major peak of activity. The isolated GST fraction was purified 50 to 70-fold with respect to cytosol for activity with 1-chloro-2,4-dinitrobenzene and had high activity with ethacrynic acid and benzo(a)pyrene-4, 5-oxide. SDS-PAGE of the purified GST showed one major band at molecular mass 27 400. Isoelectric focusing showed one major band with pI 7.9, and several minor bands. N-terminal sequence analysis of the purified GST gave 29 amino acids with marked homology (> 63% identical) to mammalian π form GST isozymes and very strong similarity (80%) to a salmon hepatic GST which was shown by immunochemical cross-reactivity to belong to the π class. An antibody to the isolated GST was prepared and used to demonstrate that 1–2% of the protein in cytosol from the proximal intestine of catfish was this π class GST. Catfish hepatic cytosol also cross-reacted strongly with the antibody.
When physicians choose to participate in the death of their patients: ethics and physician-assisted suicide.

Physicians have long aided their patients in dying in an effort to ease human suffering. It is only in the nineteenth and twentieth centuries that the prolongation of life has taken on new meaning due to the powers now available to physicians, through new drugs and high technology interventions. Whereas earlier physicians and patients could readily acknowledge that nothing further could be done, today that judgment is problematic. Most often, aiding the dying took the form of not doing anything further to prolong life. Morally, this act of restraint was not difficult, because few options could have been considered. However, some physicians, rarely, would help patients die either by hastening death directly or by increasing pain control with the risk of hastening death, the so-called double effect. When directly hastening death, physicians either directly caused the death of the patient through euthansia, or supplied the means to the patient to bring about death with or without encouragement to use these means. The latter is physician-assisted suicide (PAS).
Cathodoluminescence petrography of microstructural fabrics in deformed limestones

Abstract Cathodoluminescence petrography is a valuable tool for the analysis of strain microfabrics in deformed limestones. Finely banded growth zones in calcite cements, visible only in the cathodoluminescent mode, act as very sensitive displacement markers. They reveal the varied and heterogeneous nature of microstructures within the deformed calcite.
LONG-TERM EFFICACY OF A VAGINAL SLING PROCEDURE IN A RAT MODEL OF STRESS URINARY INCONTINENCE

ABSTRACT Purpose: We examined the long-term efficacy of a newly created vaginal sling procedure for the restoration of leak point pressure (LPP) in a rat model of stress urinary incontinence (SUI). Material and Methods: A total of 20 female Sprague-Dawley rats were randomly assigned to 1 of 4 groups, namely normal control, SUI plus vaginal sling, SUI plus sham sling and SUI only. SUI was created in the latter 3 groups by bilateral pudendal nerve transection (PNT). In the sling procedure a 2 × 0.3 cm strip of polypropylene mesh was placed at the mid urethral level. Animals in the SUI plus sham sling group underwent vaginal dissection only. After 5 weeks LPP was measured 4 or 5 times in each rat and the mean was determined. The Kruskal-Wallis and Wilcoxon rank sum tests were used to evaluate whether levels of measurements differed across and between groups. Results: Mean LPP ± SD in control rats was 48.8 ± 10.2 cm H 2 O. PNT decreased LPP to 23.5 ± 7.4 cm H 2 O. Sling placement improved LPP at 5 weeks to 35.5 ± 2.3 cm H 2 O, whereas LPP in the sham sling group was 29.1 ± 4.9 cm H 2 O. LPP recovery in the sling group was significantly above levels for PNT (p = 0.037). LPP in the sling group did not differ statistically from that in the control group (p = 0.11). Conclusions: The newly created vaginal sling model restores the LPP in the rat model of SUI in the long term (5 weeks). This model could be used to address research questions related to the sling procedure.
Relationship between acoustic backscatter strength and suspended sediment concentration using a 6 MHz Nortek Vector velocimeter.

1 ABSTRACT This paper presents a laboratory study that evaluates the relationship between suspended sediment concentration (SSC) and the acoustic backscatter strength recorded by a Nortek Vector velocimeter for dierent natural and commercial sediments. Tests were conducted in a tank using kaolinite and three other types of natural mud taken from the Houston Ship Channel. SSCs ranged from 0.001 to 7 g/l for kaolinite and 3.5 g/l for natural sediments. Results show two regions of response in the relationship between the acoustic return and the SSC. The first region was for concentrations less than 3.2 g/l. In this region, the strength of the return signal is linearly related to the logarithm of concentration with a constant positive slope. Above this concentration, the strength of the acoustic return decreases with increased concentration. The study examines the dierence in these basic trends among the dierent sediment types.
A comparative study of speech perception in young severely retarded children and normally developing infants.

The discrimination of minimally paired speech sounds by seven retarded children with a mean age of 3 years, 2 months and a mean IQ of 38.4 was compared with the discrimination performance of eight ...
Immunolocalization of tight junction proteins in blood vessels in human germinal matrix and cortex.

Brain development occurs in a specialized environment maintained by a blood–brain barrier (BBB). An important structural element of the BBB is the endothelial tight junction (TJ). TJs are present during the embryonic period, but BBB impermeability accrues over an extended gestational interval. In studies of human premature infants, we used immunomicroscopy to determine if amounts of the TJ proteins ZO-1, claudin and occludin increase with gestational age in vessels of germinal matrix (GM) and cortex. By 24 weeks postconception (PC), TJ proteins were present in both GM and cortical vessels, but immunoreactivity in the GM of the youngest subjects was less than in older subjects. At 24 weeks PC, TJ protein immunoreactivity in GM vessels was less than in cortical vessels suggesting that TJ maturation progresses along a superficial to deep brain axis. This concept correlates with conclusions from previous analyses of the expression of brain endothelial cell alkaline phosphatase (AP) activity. AP appears in cortical vessels before appearing in deep white matter and GM vessels. Together, these data indicate that differentiation of some functional specializations is still in progress in GM vessels during the third trimester. This maturation could relate to the pathogenesis of germinal matrix hemorrhage–intraventricular hemorrhage.
BACKWARD (theta = 180$sup 0$) $pi$N DISPERSION RELATIONS: APPLICATIONS TO THE INTERFERENCE MODEL P AND P' TRAJECTORIES, AND TO THE MECHANICAL FORM FACTORS OF THE NUCLEON.

On the basis of Mandelstam analyticity, crossing, and the observed drop of the backward (180\ifmmode^\circ\else\textdegree\fi{}) ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}p$ differential cross sections with energy, a set of unsubtracted dispersion relations is written for the $\ensuremath{\pi}N$ amplitudes ${A}^{\ifmmode\pm\else\textpm\fi{}}$, ${B}^{\ifmmode\pm\else\textpm\fi{}}$ at fixed $\ensuremath{\theta}=\ensuremath{\pi}$. A further application of crossing allows the derivation of separate sum rules on ${A}^{\ensuremath{-}}$ and ${B}^{+}$, which are not of the superconvergent variety, and which provide us with information about $\overline{N}N\ensuremath{\rightarrow}\ensuremath{\pi}\ensuremath{\pi}$ scattering. In particular, we are able to deduce a value of the spin-flip ${f}^{0}(1250)\ensuremath{-}N\ensuremath{-}N$ coupling constant, which is shown to permit the following observations: (1) The residue function of the $P$ (or ${P}^{\ensuremath{'}}$) trajectory in $\ensuremath{\pi}N$ scattering changes sign between $t=0$ and $t={{m}_{f}}^{2}=1.56$ ${\mathrm{GeV}}^{2}$, and (2) universal coupling of the ${f}^{0}(1250)$ meson to the gravitational stress-energy density and the knowledge of the aforementioned coupling constant fixes the zero-momentum-transfer values of two of the three mechanical form factors. The values are given in the text. Lastly, we present an extended discussion of the Barger-Cline model within the context of backward dispersion relations.
The molecular basis of ovarian cancer.

Background. Molecular genetic studies of ovarian cancer have been limited by the inaccessible location of the ovary, the advanced stage of tumors available for analysis, and the lack of a well-defined precursor lesion. However, genetic alterations important in ovarian tumorigenesis have been identified recently. Methods. Molecular genetic evaluation of ovarian cancer primarily has utilized mutation analysis, immunohistochemical techniques, and loss of heterozygosity (LOH) studies. Results. Overexpression of the HER-2/neu oncogene is present in approximately one third of ovarian cancers and is associated with poor prognosis. Mutations of the K-ras oncogene have been identified in a similar proportion of mucinous ovarian tumors, including borderline tumors. The study authors as well as others have frequently detected LOH on chromosome 17, including the p53 and BRCA1 loci, and at 17p3.3 and 1717q22-23. Genetic linkage analysis indicates that the majority of inherited ovarian cancers are caused by mutations in the BRCA1 gene. Mutations in mismatch repair genes have been identified in ovarian cancers that occur as part of the hereditary nonpolyposis colon cancer syndrome. Conclusions. Sporadic ovarian tumors are the end result of a complex pathway involving multiple oncogenes and tumor suppressor genes, including HER-2/neu, K-ras, p53, BRCA1, and additional tumor suppressor genes on chromosome 17. The majority of inherited ovarian cancers are due to mutations in the BRCA1 gene, which appears to be a tumor suppressor gene. It is hoped that an increased understanding of the molecular basis of ovarian cancer will lead to advances in prevention, diagnosis, and treatment.
Do group audiologic rehabilitation activities influence psychosocial outcomes

Purpose To attempt to determine whether group audiologic rehabilitation (AR) content affected psychosocial outcomes. Method A randomized controlled trial with at least 17 participants per group was...
Correlation of the zero field splittings with the phosphorescence rate constants and vibronic activity in the lowest triplet state of benzaldehydes by PMDR

Abstract Phosphorescence-microwave double-resonance (PMDR) techniques are used to measure the zero field splittings and the phosphorescence rate constants of individual spin levels in the lowest triplet state of benzaldehyde and several para-substituted benzaldehydes. The nature of the triplet state is discussed in terms of the spin splittings, the vibronic activity in the phosphorescence spectrum, and the phosphorescence rate constants.
Effects of ventilation on hearing loss in preterm neonates: Nasal continuous positive pressure does not increase the risk of hearing loss in ventilated neonates

Abstract Introduction There is increased risk of hearing loss in preterm neonates. This risk is further increased by environmental noise exposure especially from life support equipment such as ventilation. Nasal continuous positive airway pressure (NCPAP) used for respiratory support of preterm neonates is known to be associated with prolonged exposure to high levels of noise. However, there is paucity of information on the effect of NCPAP as compared to mechanical ventilation on hearing loss among preterm neonates. Methods A retrospective chart review was performed on neonates with birth weight (BW) Results Of 344 neonates included in the study, 61 failed hearing screen. Gestational age (p = 0.008), BW (p = 0.03), ventilation (p = 0.02), intrauterine growth retardation (p = 0.02), necrotizing enterocolitis (NEC) (p = 0.02), apnea (p Conclusion There is no increase in the hearing loss in preterm neonates treated with NCPAP as compared to mechanical ventilation despite being exposed to higher environmental noise generated by the NCPAP.
Spatial monitoring of geographic patterns: an application to crime analysis

This paper describes a new procedure for detecting changes over time in the spatial pattern of point events, combining the nearest neighbor statistic and cumulative sum methods. The method results in the rapid detection of deviations from expected geographic patterns. It may also be used for various subregions and may be implemented using time windows of differing length to search for any changes in spatial pattern that may occur at particular time scales. The method is illustrated using 1996 arson data from the Buffalo, NY, Police Department.
The use of ultrasound in the diagnosis of a large thymic cyst

Ultrasound is very useful in the assessment of anterior mediastinal masses in childhood. In this case knowledge of the completely cystic nature of the mass and its finely septated nature not only aided in the diagnosis but also in the surgical removal of an extremely large thymic cyst.
Graft copolymers: Synthesis and characterization

True 100% grafted polymers were prepared in a two-stage emulsion polymerization process. Microgels of styrene crosslinked with divinylbenzene, methyl acrylate crosslinked with divinylbenzene, and acrylonitrile crosslinked with methylene-bisacrylamide were used as first stage polymers, and the grafting of styrene and acrylonitrile were studied. The polymers were analyzed as microsols by limiting viscosity number and by ultracentrifuge measurements. In the ultracentrifuge the quantitative separation of crosslinked particles from linear polymers was demonstrated. From a study of the polymerization conditions which result in a single sedimenting component in the ultracentrifuge, 100% grafted polymers were synthesized. The results indicated that in order to obtain 100% grafting initiation must be by free radicals present in the polymer particles with none from residual catalyst or by thermal initiation. The existence of polymeric free radicals of lives greater than 100 days is demonstrated.
Relationship of circulating estrogen and progesterone concentrations during late pregnancy and the onset phase of maternal behavior in the ewe

Abstract Maternal behavior in several species has been stimulated with exogenous estrogen and this behavior can be blocked with progesterone (P4). In this study, attempts are made to correlate the ewe's endogenous pattern and concentrations of these two steroid hormones during late gestation with specific maternal behaviors. Five yearling ewes with known breeding dates were fully acclimated to the presence of the investigator during the gestation period. Each ewe was allowed to parturiate in the location of her choice within the small barn and paddock in which she had been housed throughout gestation, and specific maternal behaviors were recorded. All areas of the facility were equally observable to the investigator. Blood was collected daily at 16:00 h via jugular venipuncture from 21 days prior to the expected lambing date until the day of parturition. Estrogen (estrone + estradiol-17s; E) and P4 were measured in plasma by radioimmunoassay. High correlations were observed between E concentrations 2–3 days prepartum and maternal behaviors displayed by the ewe during the first 4 h postpartum. Specific maternal behaviors and correlations are: (1) time from the completion of birth to the start of grooming (r=−0.97); (2) percentage of suckling attempts accepted by the ewe (r=0.99); (3) mean number of vocalizations per min by the ewe (r=−0.96); (4) percentage of time of direct contact between ewe and lamb (r=0.95). High positive correlations were also observed between P4 concentrations on the day of parturition and the time from the completion of birth to the start of grooming (r=0.97), as well as the mean number of vocalizations per min by the ewe (r=0.99). These data suggest that E exposure 2–3 days prepartum facilitates maternal behavior during the immediate postpartum period whereas P4 exposure inhibits such behavior.
Practice of 3-dimensional treatment planning at the Fox Chase Cancer Center, University of Pennsylvania.

Summary The use of 3-dimensional (3-D) dose distributions and dose-volume histograms in radiation therapy treatment planning is illustrated on a patient with a head and neck tumor. The patient was immobilized in a rectangular tissue compensation bolus box. The treatment was planned with a 14 MeV D-T derived fast neutron therapy beam. The isodose distributions and the dose-volume histograms at multiple adjacent levels are used to evaluate the adequacy of coverage of target volumes and the doses to the normal tissues. Such dose-volume histograms are useful and practical in summarizing the dose distribution throughout the irradiated volume, assessing the degree of uniformity of the dose distribution within the target volume, quantifying the amount of normal tissue irradiated, and evaluating rival treatment plants for both particle and nonparticle beams.
Theoretical Modeling of Frequency-Chirped Optical Pulses in Birefringent Single-Mode Fibers

Abstract We analyze nonlinear coupling of polarized solitons in the presence of initial frequency chirp on the basis of a theoretical model described by a coupled nonlinear Schrodinger equations. We also obtain a threshold condition for the bound state of two polarizations and show analytically that the threshold amplitude for soliton trapping can be controlled by varying the chirp parameter.
Effects of concentration and clusters in EDFAs

Strong interest in heavily doped erbium-doped waveguides1 and in the applications of heavily doped erbium-doped fibers (EDFs) in lasers has resulted in several recent studies of collective processes in erbium ions. Rapid cross relaxation within a fraction of clustered ions, called pair-induced quenching (PIQ), has been identified as the main cause of EDF performance degradation.2-4 To date, studies on the dependence of EDF performance on ion concentration have been focused on pair/cluster-induced nonsaturable absorption of EDFs,2 which leads to the reduced quantum efficiency (QE) of EDF lasers.4 Recently, detailed theoretical analysis of the effect of PIQ on the performance of erbium-doped fiber amplifiers (EDFAs) has also been reported.4
Obstructive lesions of the equine upper respiratory tract Part 2: Surgical options and expected outcomes: Part 2

DORSAL DISPLACEMENT OF THE SOFT PALATE Dorsal displacement of the soft palate (DDSP) is the most common obstructive upper airway lesion detected in racing horses. The normal anatomical alignment of the nasopharynx has the free margin of the epiglottis resting on the dorsal aspect of the soft palate. In this condition, the alignment becomes reversed, with the free border of the soft palate now coming to rest dorsal to the epiglottis (Figs. 1a and 1b). As a result, there is complete loss of the palatopharyngeal seal and an affected horse will be able to expire through its mouth.
Identification and characterization of alternatively spliced variants of DNA methyltransferase 3a in mammalian cells.

Abstract CpG methylation is mediated by the functions of at least three active DNA methyltransferases (DNMTs). While DNMT1 is thought to perform maintenance methylation, the more recently discovered DNMT3a and DNMT3b enzymes are thought to facilitate de novo methylation. Murine Dnmt3a and 3b are developmentally regulated and a new Dnmt3a isoform, Dnmt3a2, has been recently shown to be expressed preferentially in mouse embryonic stem (ES) cells. Here we have characterized four alternatively spliced variants of human and mouse DNMT3a. These transcripts included a novel exon 1 (1β) that was spliced into the same exon 2 acceptor splice site used by the original exon 1 (1α). Cloning and sequencing of the 5′ region of the human DNMT3a gene revealed that exon 1β was situated upstream of exon 1α and that the entire region was contained within a CpG island. We also identified other alternatively spliced species containing intron 4 inclusions that were associated with either exon 1α or 1β. These were expressed at low levels in mouse and human cells. All transcripts were highly conserved between human and mouse. The levels of Dnmt3a mRNA containing exon 1β were 3–25-fold greater in mouse ES cells than in various somatic cells as determined by semiquantitative reverse transcription–polymerase chain reaction analysis, while the levels of exon 1α-containing transcripts were slightly higher in human and mouse somatic cells. The preferential expression of the β transcript in ES cells suggests that this transcript, in addition to Dnmt3a2, may also be important for de novo methylation during development.
An automated method for predicting iris segmentation failures

Arguably the most important task in iris recognition systems involves localization of the iris region of interest, a process known as iris segmentation. Research has found that segmentation results are a dominant factor that drives iris recognition matching performance. This work proposes techniques based on probabilistic intensity features and geometric features to arrive at scores indicating the success of both pupil and iris segmentation. The technique is fully automated and therefore requires no human supervision or manual evaluation. This work also presents a machine learning approach which utilizes the pupil and iris scores to arrive at an overall iris segmentation result prediction. We test the techniques using two iris segmentation algorithms of varying performance on two publicly available iris datasets. Our analysis shows that the approach is capable of arriving at segmentation scores suitable for predicting both the success and failure of pupil or iris segmentation. The proposed machine learning approach achieves an average classification accuracy of 98.45% across the four combinations of algorithms and datasets tested when predicting overall segmentation results. Finally, we present one potential application of the technique specific to iris match score performance and outline many other potential uses for the algorithm.
The undesired self: Deadly connotations

Abstract Two studies were conducted to examine the hypothesis derived from a juxtaposition of the undesired self and terror management theories that making aspects of the undesired self salient produces effects comparable to those obtained in response to making mortality salient. In Study 1, participants reminded of either death or aspects of their undesired self were more supportive of President George W. Bush and his policies in Iraq, relative to participants in exam salient or desired self salient control conditions. In Study 2, participants reminded of death or aspects of their undesired self showed greater accessibility of implicit death thoughts, relative to participants in pain salient or desired self salient control conditions. Implications of these findings for future theory and research are considered.
Update on endoscopic treatment of chronic pancreatitis

Endoscopic therapy has been increasingly recognized as the effective therapy in selected patients with chronic pancreatitis. Utility of endotherapy in various conditions occurring in chronic pancreatitis is discussed. Its efficacy, limitations, and alternatives are addressed. For the best management of these complex entities, a multidisciplinary approach involving expertise in all pancreatic specialties is essential to achieve the goal.
On the geochemistry of fullerenes: Stability of C60 in ambient air and the role of ozone

Abstract The chemical in ambient air responsible for degradation of fullerenes is ozone. The destruction of C60 in toluene proceeds at least 5 orders of magnitude faster with O3 than it does with O2. Ozonation of C60 in toluene resulted in the formation of C60O, C60O2, and C60O3. Oxides were not formed when crystalline C60 was exposed to O3. C60O was destroyed when heated in ambient air. The long-term survival of C60 in nature seems to require an environment low in O3
New Concepts on Two-Dimensional Data Visualization With Applications in Engineering Analysis and Design

The use of information visualization in engineering analysis and design has increased exponentially, making it indispensable in science and engineering education. In this paper, several new concepts on graphical representation of two-dimensional data are presented, and their implementation in a computer program called D 2D detailed. Application examples include mechanism kinematics, vibrations, and optimizations. New ideas on plotting inequalities of two variables, damping ratio evaluation of single degree-of-freedom vibratory systems, and time ratio calculation of crank-driven mechanisms are presented in paper. [DOI: 10.1115/1.4006204]
X-ray diffraction study on pressure-induced phase transformations in nanocrystalline anatase/rutile (TiO2)

An in situ x-ray diffraction study was conducted to study the pressure-induced phase transformation in nanocrystalline anatase/rutile (TiO2) to 35.1 GPa. The nano-anatase phase remains stable to approximately 16.4 GPa, and then transforms to an amorphous phase, which is returned upon release of pressure. The nano-rutile phase starts to transform to the baddeleyite (ZrO2) structure at ~8.7 GPa, and the transformation is complete at approximately 16.4 GPa. On release of pressure the ZrO2 structure transforms to the α-PbO2 structure. The results are compared to previous work on phase changes in TiO2 with different particle sizes.
Public Administration and the Public Interest Re-Presenting a Lost Concept

This article analyzes how the concept of the public interest has been articulated in the field of public administration. It traces the intellectual development of the term and highlights the differ...
Structural analysis of local search heuristics combinatorial optimization

Abstract Neighborhood, or local, search is a popular and practical heuristic for many combinational optimization problems. We examine the neighborhood structures of two classes of problems, 0–1 integer programming and the mean tardiness job sequencing problem—from the viewpoint of state-space graphs in artificial intelligence. Such analysis is shown to provide fundamental insights into the nature of local search algorithms and provides a useful framework for evaluating and comparing such heuristics. Computational results are presented to support these observations.
Work Fluctuation Theorems and Single-Molecule Biophysics

Work fluctuation theorems offer a new set of theoretical tools for studying problems of biophysical interest. I will discuss issues related to both the practical application of these tools in the context of single-molecule experiments and simulations, and the interpretation of the quantities appearing in these theorems.
Mortality within 24 hours of thrombolysis for myocardial infarction. The importance of early reperfusion. The GUSTO Investigators, Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries.

BACKGROUNDA paradoxical increased risk of death has been reported during the first 24 hours after thrombolysis for myocardial infarction. The mechanism of this phenomenon is not known, nor is its relation to the success or failure of reperfusion. The present study was a prospectively designed analysis of deaths occurring within the first 24 hours in the GUSTO trial.METHODS AND RESULTSThere were 41,021 patients enrolled in GUSTO, a randomized comparison of streptokinase with intravenous or subcutaneous heparin, accelerated tissue-type plasminogen activator (TPA), and combination of streptokinase and TPA. An angiographic mechanistic substudy examined reperfusion (using the TIMI flow grading criteria) 90 minutes after the assigned thrombolytic regimen was begun in 1567 patients. There were 1125 deaths (2.8%) within 24 hours ("early deaths") and 1726 additional deaths (4.2%) after 24 hours but within 30 days ("later deaths"). At the time of presentation, the most potent predictors of early death were hypotens...
New Theoretical Results on Channelized Hotelling Observer Performance Estimation With Known Difference of Class Means

Task-based assessments of image quality constitute a rigorous, principled approach to the evaluation of imaging system performance. To conduct such assessments, it has been recognized that mathematical model observers are very useful, particularly for purposes of imaging system development and optimization. One type of model observer that has been widely applied in the medical imaging community is the channelized Hotelling observer (CHO). Since estimates of CHO performance typically include statistical variability, it is important to control and limit this variability to maximize the statistical power of image-quality studies. In a previous paper, we demonstrated that by including prior knowledge of the image class means, a large decrease in the bias and variance of CHO performance estimates can be realized. The purpose of the present work is to present refinements and extensions of the estimation theory given in our previous paper, which was limited to point estimation with equal numbers of images from each class. Specifically, we present and characterize minimum-variance unbiased point estimators for observer signal-to-noise ratio (SNR) that allow for unequal numbers of lesion-absent and lesion-present images. Building on this SNR point estimation theory, we then show that confidence intervals with exactly-known coverage probabilities can be constructed for commonly-used CHO performance measures. Moreover, we propose simple, approximate confidence intervals for CHO performance, and we show that they are well-behaved in most scenarios of interest.
The stabilization of nonlinear servomechanisms encountered in antenna instrumentation

This paper investigates the problem of compensating the loop-gain of instrument servos to provide uniform transient response over a wide dynamic operating range. Particular consideration is given to applications in the realm of antenna measurements. A distinction is made between situations where the nonlinearity results from characteristics of the follow-up device and where it results from the loop-gain being functionally related to an external variable. In the former case the loop-gain is made self-linearizing; in the latter the gain is effectively equalized with an auxiliary logarithmic servo. This necessarily requires a suitable slave potentiometer in the nonlinear loop, actuated by the logarithmic servo. Certain advantages resulting from the use of ladder attenuator as the slave component are described. It is shown how this combination logarithmic servo and ladder slave attenuator can make a loop-gain invariable which otherwise would be functionally related to a variable E by the equation G = E\pm N. The idea is extended to the generation of polynominal terms of the same form as G .
The barrier properties of polyacrylonitrile

Abstract The permeabilities and time lags characterizing transport in machine-cast polyacrylonitrile (PAN) films have been determined for helium, neon, argon, krypton, oxygen, nitrogen, and carbon dioxide. The measured permeabilities were decreased slightly and the observed time lags were increased consequent to scrupulous removal of residual solvent. The activation energies for permeation were not changed consequent to film purification, however. In all cases, the measured permeabilities were remarkably low. The permeability of PAN to helium was inordinately higher than the observed permeability of PAN to the other gases studied. The relatively high permeability to helium and the low activation energies for permeation suggest that the excellent barrier properties of PAN are related to the very small size of the fluctuating free volume elements involved in the rate-determining transport step for fixed gases in and through this particular polymer.