cssi/SciSciGPT-SciSciNet huggingface dataset:
The toxicity of the Aggregatibacter actinomycetemcomitans cytolethal distending toxin correlates with its phosphatidylinositol‐3,4,5‐triphosphate phosphatase activity

The Aggregatibacter actinomycetemcomitans cytolethal distending toxin (Cdt) induces G2 arrest and apoptosis in lymphocytes and other cell types. We have shown that the active subunit, CdtB, exhibits phosphatidylinositol-3,4,5-triphosphate (PIP3) phosphatase activity, leading us to propose that Cdt toxicity is the result of PIP3 depletion and perturbation of phosphatidylinositol-3-kinase (PI-3K)/PIP3/Akt signalling. To further explore this relationship, we have focused our analysis on identifying residues that comprise the catalytic pocket and are critical to substrate binding rather than catalysis. In this context, we have generated several CdtB mutants and demonstrate that, in each instance, the ability of the toxin to induce cell cycle arrest correlates with retention of phosphatase activity. We have also assessed the effect of Cdt on downstream components of the PI-3K signalling pathway. In addition to depletion of intracellular concentrations of PIP3, toxin-treated lymphocytes exhibit decreases in pAkt and pGSK3β. Further analysis indicates that toxin-treated cells exhibit a concomitant loss in Akt activity and increase in GSK3β kinase activity consistent with observed changes in their phosphorylation status. We demonstrate that cell susceptibility to Cdt is dependent upon dephosphorylation and concomitant activation of GSK3β. Finally, we demonstrate that, in addition to lymphocytes, HeLa cells exposed to a CdtB mutant that retains phosphatase activity and not DNase activity undergo G2 arrest in the absence of H2AX phosphorylation. Our results provide further insight into the mode of action by which Cdt may function as an immunotoxin and induce cell cycle arrest in target cells such as lymphocytes.
Non-rigid Image Registration with Equally Weighted Assimilated Surface Constraint

An important research problem in image-guided radiation therapy is how to accurately register daily onboard Cone-beam CT (CBCT) images to higher quality pretreatment fan-beam CT (FBCT) images. Assuming the organ segmentations are both available on CBCT and FBCT images, methods have been proposed to use them to help the intensity-driven image registration. Due to the low contrast between soft-tissue structures exhibited in CBCT, the interobserver contouring variability (expressed as standard deviation) can be as large as 2-3 mm and varies systematically with organ, and relative location on each organ surface. Therefore the inclusion of the segmentations into registration may degrade registration accuracy. To address this issue we propose a surface assimilation method that estimates a new surface from the manual segmentation from a priori organ shape knowledge and the interobserver segmentation error. Our experiment results show the proposed method improves registration accuracy compared to previous methods.
The new engineering graphics

The authors examine the basic mission of engineering graphics in light of developments in computer graphics. They address the questions: Where does computer graphics fit within engineering graphics? Where does computer graphics/modeling fit within engineering design? Is there an advantage to engineering drawing over computer geometric modeling? They also address theoretical difficulties which arise between technical drawing and computer geometric modeling such as whether geometric modeling 'Is geometric modelling, indeed, graphics?'; the redefining of engineering graphics, computer geometric modeling, engineering design, 2-D/3-D drawing/geometric modeling, and virtual space. >
Serious Game Simulation as a Teaching Strategy in Pharmacology

Abstract Background The purpose of this pilot study was to explore student learning through the use of a serious game (SG) simulation. Method A pre-test/post-test design was used to measure knowledge. Importance of the SG simulation design and satisfaction and self-confidence were also measured. Results Seventy-nine (n = 79) students participated in this SG simulation. There was a significant increase in scores between pre- and post-tests (p Conclusions SG simulation may be an effective teaching strategy and has promise as an emerging pedagogical approach.
Expanding Epistemology: A Responsibilist Approach

The first section of this paper asks why we need, or what would motivate, a meaningful expansion of epistemology. It answers with three critical arguments found in the recent literature, which each purport to move us some distance beyond the preoccupations of ‘post-Gettier era' analytic epistemology. These three—the ‘epistemic luck,' ‘epistemic value' and ‘epistemic reconciliation' arguments associated with Duncan Pritchard, Jonathan Kvanvig, and Michael Williams, respectively—each carry this implication of needed expansion by functioning as forceful ‘internal critiques' of the tradition. The second section of the paper asks what specific directions an expanded field of epistemology should take. While this is taken as an open question for debate, the expansion suggested here remains continuous with the analytic tradition, while also underlining the centrality of the acquired or ‘reflective' intellectual virtues in meeting the burdens of the three arguments. Responsibilism, as here understood, is not a philosophical thesis so much as an orientation of commitment to clearing away philosophical assumptions that systematically obstruct recognition of the importance of empiricallyinformed research programs into the reflective virtues. Philosophical Papers Vol. 37 (1) 2008: pp. 51-87
Children's Understanding of the Speaker's Meaning in Referential Communication.

Abstract Speakers often use ambiguous referential utterances to inform listeners about specific referents. The four experiments examined constraints on children′s understanding of the speaker′s meaning in using such utterances concerning evaluation of knowledge sufficiency, access to common ground information in memory, and response decision processes for dealing with insufficiency. Kindergarten, second-grade, and fourth-grade children listened to short vignettes containing a referential utterance that was ambiguous or informative about the intended referent in a display. For the ambiguous utterances, the context variably contained information useful for the identification of the referent. After each vignette, the children were asked about knowledge sufficiency and asked to pick the referent or respond "don′t know." The format of the contextual information was varied in each experiment as a way of determining problems of memory access, and Experiments 2, 3, and 4 contained direct manipulations of memory variables. Experiment 1 addressed children′s response decision processes. The results provided systematic information about the role of memory variables and response decisions processes in interpreting ambiguous referential utterances, established the importance of distinguishing between evaluation and regulation processes in children′s monitoring of referential ambiguity, and established surprising competence in 5-year olds in evaluating knowledge sufficiency.
Uniform Waveguide Leaky Wave Antennas

Traveling wave antennas for the millimeter wave range face two main problems: increased metal loss, and fabrication difficulties due to the smaller wavelengths. To overcome these two problems, a new class of uniform leaky wave antennas have been introduced. The antennas are longitudinally continuous to minimize the fabrication problems, and they are based on low-loss waveguides, such as groove guide and nonradiative dielectric (NRD) guide, to reduce the effects of higher loss. New techniques for obtaining controlled leakage have also been investigated. Four different leaky wave antenna structures are discussed here, two based on groove guide and two on NRD guide.
Noether's theorem and the fieldB(3)

It is shown that the longitudinal, magnetic flux density,B (3) , of vacuum electromagnetic radiation can be accommodated rigorously within Noether's theorem, which relates fundamental spacetime symmetries to fundamental conservation laws. This demonstration linksB (3) to the canonical energy-momentum tensorTµv that appears in Einstein's field equations of general relativity. Thus,B (3) provides a link between electromagnetism and gravitation which might eventually lead to an unified understanding of field theory.
Polymer Nanocomposites through Controlled Self-Assembly of Cubic Silsesquioxane Scaffolds

A novel bottom-up approach to obtain polymer nanocomposites using cubic silsesquioxanes (POSS) nanoparticles as building blocks is reported. The design is based on associative interaction between particles to form ordered nanostructure and limited crystal growth to render anisotropic shapes. Specifically, the affinity between POSS units causes these particles to aggregate and closely pack into a crystalline lattice. The organic polymer, covalently connected to each POSS unit, limits the crystallization into a two-dimensional lattice as demonstrated in random copolymers of polybutadiene and cubic silsesquioxanes. The copolymers were synthesized by ring-opening metathesis copolymerization of cyclooctadiene and POSS bearing a polymerizable norbornene group. The polymers were characterized using NMR, DSC, TEM, WAXD, and SAXS. The data from TEM and X-ray diffraction clearly show the formation of two-dimensional lamellar-like nanostructures of assembled cubic silsesquioxanes.
Sources of variability in semi-anechoic chamber radiated emissions measurement

Investigations into the sources of variability in radiated emissions testing to CISPR 25 were conducted in a 6.7 m/spl times/3.7 m/spl times/3.2 m semi-anechoic chamber. A large number of potential sources of variability were identified and experiments conducted to quantify the level of variability each potential source introduced to the measurement of radiated emission. A commercial wide-band comparison noise emitter (CNE) was used as an emission source. Three different receiving antennas (biconical, log-periodic-biconical and horn) were used to assess some of the emission variability due to different antenna structures. Other elements of variability examined include cable placement, effect of detector type and positional accuracy. It is believed that this is the first reported quantified analysis of the effect of many of the investigated variables on radiated emission levels in a compact chamber. This study should enable higher precision results in semi-anechoic chamber radiated emission tests by appropriate control of emission variability within the test environment. Ultimately the data could improve specification writing for EMC radiated emissions testing.
Accuracy and Consistency of Water-Current Mieters

The measurement of discharge in natural streams requires hydrographers to use accurate meters that have consistent performance among meters of the same model. This paper presents the results of an investigation into the accuracy and consistency of four models of current meters - Price Type-AA, Price Pygmy, Marsh McBirney 2000, and Swoffer 2100. Test results for six meters of each model are presented. Variation of meter performance within a model is used as an indicator of consistency, and percent velocity error that is computed from a measured reference velocity is used as an indicator of meter accuracy. Velocities measured by each meter are also compared to the manufacturer's published or advertised accuracy limits. The investigation found the Price models to be more accurate and consistent than the other models. The Price models met their respective accuracy limits over the range of test velocities better than the other models. The Marsh McBirney model usually measured within its accuracy specification. The Swoffer meters did not meet the stringent Swoffer accuracy limits for all the velocities tested. The Swoffer model had accuracies similar to the Price Type-AA model when individual meter rating equations were computed and used. Every model tested had meters that did not meet manufacturer accuracy limits. Because current meters are not consistently accurate within a model, hydrographers should periodically check meters against a velocity standard.
Evaluation of Electron-Withdrawing Group Effects on Heme Binding in Designed Proteins: Implications for Heme a in Cytochrome c Oxidase

Heme a, the metalloporphyrin cofactor unique to cytochrome c oxidases, differs from the more common heme b by two chemical modifications, a C-2 hydroxyethylfarnesyl group and a C-8 formyl group. To elucidate a role of the C-8 formyl group, we compare the heme affinity, spectroscopy, and electrochemistry of a heme a mimic, Fe(diacetyldeuterioporphyrin IX) or Fe(DADPIX), with heme b, Fe(protoporphryrin IX) or Fe(PPIX), incorporated into a designed heme protein. The [Delta7-H3m]2 protein ligand, or maquette, selected for this study contains two equivalent bis-(3-methyl-L-histidine) heme binding sites within a four-alpha-helix bundle scaffold. The spectroscopic data on Fe(PPIX) and Fe(DADPIX) bound to [Delta7-H3m]2 demonstrate that these complexes are excellent synthetic analogues for natural cytochromes b and a, respectively. Comparison of the spectroscopic, electrochemical, and equilibrium thermodynamic data measured for the Fe(PPIX)-[Delta7-H3m]2 maquette with the previously reported Fe(PPIX)-[Delta7-His]2 complex demonstrates that changing the heme axial ligands to 3-methyl-L-histidine from L-histidine does not alter the resulting heme protein properties significantly in either oxidation state. Heme binding studies demonstrate that [Delta7-H3m]2 binds two ferrous Fe(DADPIX) or Fe(PPIX) moieties with similar dissociation constant values. However, in the ferric state, the data show that [Delta7-H3m]2 only binds a single Fe(DADPIX) and that one 2500-fold weaker than oxidized Fe(PPIX). The data demonstrate that the 4.6 kcal mol(-1) weakened affinity of [Delta7-H3m]2 for oxidized Fe(DADPIX) results in the majority of the 160 mV, 3.7 kcal mol(-1), positive shift in the heme reduction potential relative to Fe(PPIX). These data indicate that a role of the formyl group on heme a is to raise the iron reduction potential, thus making it a better electron acceptor, but that it does so by destabilizing the affinity of bis-imidazole sites for the ferric state.
Nucleotide sequences that signal the initiation of transcription and translation in Bacillus subtilis

We have determined the nucleotide sequence of twoBacillus subtilis promoters (veg andtms) that are utilized by the principal form ofB. subtilis RNA polymerase found in vegetative cells (σ55-RNA polymerase) and have compared our sequences to those of several previously reportedBacillus promoters. Hexanucleotide sequences centered approximately 35 (the “-35” region) and 10 (the “-10” region) base pairs upstream from theveg andtms transcription startpoints (and separated by 17 base pairs) corresponded closely to the consensus hexanucleotides (TTGACA and TATAAT) attributed toEscherichia coli promoters. Conformity to the preferred -35 and -10 sequences may not be sufficient to promote efficient utilization byB. subtilis RNA polymerase, however, since three promoters (veg, tms andE. coli tac) that conform to these sequences and that are utilized efficiently byE. coli RNA polymerase were used with highly varied efficiencies byB. subtilis RNA polymerase.
DNA supercoiling allows enhancer action over a large distance

Enhancers are regulatory DNA elements that can activate their genomic targets over a large distance. The mechanism of enhancer action over large distance is unknown. Activation of the glnAp2 promoter by NtrC-dependent enhancer in Escherichia coli was analyzed by using a purified system supporting multiple-round transcription in vitro. The data suggest that DNA supercoiling is an essential requirement for enhancer action over a large distance (2,500 bp) but not over a short distance (110 bp). DNA supercoiling facilitates functional enhancer-promoter communication over a large distance, probably by bringing the enhancer and promoter into close proximity.
Mechanistic differences in the activation of estrogen receptor-α (ERα)- and ERβ-dependent gene expression by cAMP signaling pathway(s)

Although increases in intracellular cAMP can stimulate estrogen receptor-α (ERα) activity in the absence of exogenous hormone, no studies have addressed whether ERβ can be similarly regulated. In transient transfections, forskolin plus 3-isobutyl-1-methylxanthine (IBMX), which increases intracellular cAMP, stimulated the transcriptional activities of both ERα and ERβ. This effect was blocked by the protein kinase A inhibitor H89 (N-(2-(p-bromocinnamylamino)-ethyl)-5-isoquinolinesulfonamide) and was dependent on an estrogen response element. A 12-O-tetradecanoylphorbol-13-acetate response element (TRE) located 5′ to the estrogen response element was necessary for cAMP-dependent activation of gene expression by ERβ but not ERα, indicating that the former subtype requires a functional interaction with TRE-interacting factor(s) to stimulate transcription. Both p160 and CREB-binding protein coactivators stimulated cAMP-induced ERα and ERβ transcriptional activity. However, mutation of the two cAMP-inducible SRC-1 phosphorylation sites important for cAMP activation of chicken progesterone receptor or all seven known SRC-1 phosphorylation sites did not specifically impair cAMP activation of ERα. The E/F domains of ERα are sufficient for activation by forskolin/IBMX, and this is accompanied by an increase in receptor phosphorylation. In contrast, cAMP signaling reduces the phosphorylation of the corresponding region of ERβ, and this correlates with the lack of forskolin/IBMX stimulated transcriptional activity. Our data suggest that cAMP activation of ERα transcriptional activity is associated with receptor instead of SRC-1 phosphorylation. Moreover, differences in the cofactor requirements, domains of ERα and ERβ sufficient for forskolin/IBMX activation, and the effect of cAMP on receptor phosphorylation indicate that this signaling pathway utilizes distinct mechanisms to stimulate ERα and ERβ transcriptional activity.
Standardized and reproducible methodology for the comprehensive and systematic assessment of surgical resection margins during breast-conserving surgery for invasive breast cancer

The primary goal of breast-conserving surgery (BCS) is to completely excise the tumor and achieve "adequate" or "negative" surgical resection margins while maintaining an acceptable level of postoperative cosmetic outcome. Nevertheless, precise determination of the adequacy of BCS has long been debated. In this regard, the aim of the current paper was to describe a standardized and reproducible methodology for comprehensive and systematic assessment of surgical resection margins during BCS. Retrospective analysis of 204 BCS procedures performed for invasive breast cancer from August 2003 to June 2007, in which patients underwent a standard BCS resection and systematic sampling of nine standardized re-resection margins (superior, superior-medial, superior-lateral, medial, lateral, inferior, inferior-medial, inferior-lateral, and deep-posterior). Multiple variables (including patient, tumor, specimen, and follow-up variables) were evaluated. 6.4% (13/204) of patients had positive BCS specimen margins (defined as tumor at inked edge of BCS specimen) and 4.4% (9/204) of patients had close margins (defined as tumor within 1 mm or less of inked edge but not at inked edge of BCS specimen). 11.8% (24/204) of patients had at least one re-resection margin containing additional disease, independent of the status of the BCS specimen margins. 7.1% (13/182) of patients with negative BCS specimen margins (defined as no tumor cells seen within 1 mm or less of inked edge of BCS specimen) had at least one re-resection margin containing additional disease. Thus, 54.2% (13/24) of patients with additional disease in a re-resection margin would not have been recognized by a standard BCS procedure alone (P < 0.001). The nine standardized resection margins represented only 26.8% of the volume of the BCS specimen and 32.6% of the surface area of the BCS specimen. Our methodology accurately assesses the adequacy of surgical resection margins for determination of which individuals may need further resection to the affected breast in order to minimize the potential risk of local recurrence while attempting to limit the volume of additional breast tissue excised, as well as to determine which individuals are not realistically amendable to BCS and instead need a completion mastectomy to successfully remove multifocal disease.
Aging: Effects on β-carboline binding in hippocampal subfields

Abstract —The CA1 and CA4/area dentata subfields of the hippocampus in young, mature and old rats were examined for age-related change in propyl β-carboline-3-carboxylate (PrCC) binding. 3 H-PrCC bound with high affinity (K d =0.82 nM) to one binding site when ethyl β-carboline-3-carboxylate was used to delineate specific binding. An age dependent change in the maximum number of 3 H-PrCC binding sites in the CA1 and CA4/area dentate subfields of the hippocampus were assessed by using a saturating (6 nM) concentration of 3 H-PrCC. Although 3 H-PrCC specific binding at a saturating concentration (6 nM) was significantly less in both the CA1 and CA4/area dentata subfields of the senescent rat, the magnitude of the decrease was greater in the CA1 region. In addition, the affinity of the 3 H-PrCC binding site in both subfields probably did not vary significantly with age. Therefore, the CA1 and CA4/area dentate of the rat hippocampus may not only lose BZ 1 receptors or the BZ 1 receptors conformation with age, but the severity of receptor or receptor conformation loss varies with the subfield.
TRANSVERSALITY FOR HOMOLOGY MANIFOLDS

Abstract Transversality phenomena are studied for homology manifolds. For homology manifolds X , Y and Z , with Z embedded in Y with a neighborhood ν ( Z ) which has a given bundle structure, we define a map f : X→Y to be transverse to Z , if f -1 ( Z )= Z ′ is a homology manifold, the neighborhood f -1 ( ν ( Z )) has a bundle structure given by f ∗ ν(Z) and f induces the bundle map. In the case where the range is a manifold an arbitrary map is s-cobordant to a transverse map if the submanifold is codimension one and (π, π) or codimension ⩾3. Appropriate homology manifold versions of related splitting and embedding theorems are proved for homology manifolds. As a group, bordism of high dimensional homology manifolds has one copy of the bordism of topological manifolds for each possible index.
Ureteral stent insertion for gynecologic interstitial high-dose-rate brachytherapy

PURPOSE: To determine the utility of ureteral stents in interstitial gynecological brachytherapy. METHODS AND MATERIALS: We reviewed 289 patients with cervix cancer treated with high- dose-rate interstitial brachytherapy who did not have pretreatment hydronephrosis to determine the relative incidence of benign ureteral strictures after treatment. We also did comparative dosimetry analysis in five cases of high-dose-rate brachytherapy. Bilateral ureteral stents were placed during the procedure. Three dosimetry plans were created to determine the impact of modifying clinical target volume (CTV) and applying ureteral dose constraints. In Plan 1, the ureters were contoured and excluded from the CTV and 120% dose constraints were applied. In Plan 2, the ureters were contoured and excluded, but no dose constraints were applied to the ureter. In Plan 3, the CTV was created as if the location of the ureters was unknown and then ureteral dose was determined. RESULTS: There were 11 ureteral strictures observed in 255 nonstented cases and 0 ureteral stric- tures in 34 stented cases. Plan 1 reduced the ureter dose (D0.1cc) by a median 22% (7.0e53.8%) compared with Plan 2 and by a median of 30.9% (12.3e65%). compared with Plan 3. CONCLUSIONS: Placement of stents and ureteral dose constraints facilitates dosimetry and re- duces the dose to ureters. Temporary ureteral stents prevent obstruction during interstitial gyneco- logic brachytherapy and allows the ureters to be addressed as an organ at risk. 2015 Published by Elsevier Inc. on behalf of American Brachytherapy Society.
Biological response modifiers in the management of viral infection.

The role of biological response modifiers (BRMs) in veterinary medicine has traditionally centered around therapeutic augmentation in cancer patients. This article describes the emerging role of immunopharmacology in the clinical management of animals with viral infections. The proposed mechanisms of action and indications for treatment of several BRMs having a known or potential role in the management of viral infections are reviewed.
The human dimension of development in India

This paper provides an overview of the level of economic development in India, with a brief explanation of the factors that have impeded rapid growth of the economy. Against this background information, the paper focuses on some social programs undertaken by government and non-governmental agencies to help the most vulnerable segments of society to deal with the adverse effects of industrialization and urbanization and to share in the benefits of economic development.
The pebble-crunching model for fault-tolerant load balancing in hypercube ensembles

We propose a graph-theoretic, receiver-initiated, distributed protocol for dynamic load balancing protocol in large-scale hypercube ensembles. Using attributed hypergraphs as the primary data structure for constraint modelling and dynamic optimisation, we consider systems running precedence-constrained heterogeneous tasks. Fault Tolerance is ensured by incorporating a dynamic integrity check for the decision nodes and their subsequent re-election if needed. Simulation studies are used to analyse the algorithm performance and correctness
Steganography anomaly detection using simple one-class classification

There are several security issues tied to multimedia when implementing the various applications in the cellular phone and wireless industry. One primary concern is the potential ease of implementing a steganography system. Traditionally, the only mechanism to embed information into a media file has been with a desktop computer. However, as the cellular phone and wireless industry matures, it becomes much simpler for the same techniques to be performed using a cell phone. In this paper, two methods are compared that classify cell phone images as either an anomaly or clean, where a clean image is one in which no alterations have been made and an anomalous image is one in which information has been hidden within the image. An image in which information has been hidden is known as a stego image. The main concern in detecting steganographic content with machine learning using cell phone images is in training specific embedding procedures to determine if the method has been used to generate a stego image. This leads to a possible flaw in the system when the learned model of stego is faced with a new stego method which doesn't match the existing model. The proposed solution to this problem is to develop systems that detect steganography as anomalies, making the embedding method irrelevant in detection. Two applicable classification methods for solving the anomaly detection of steganographic content problem are single class support vector machines (SVM) and Parzen-window. Empirical comparison of the two approaches shows that Parzen-window outperforms the single class SVM most likely due to the fact that Parzen-window generalizes less.
Relationship between psychopathology and cognitive functioning in elderly persons.

There has been much controversy over the common belief that elderly people incur declining cognitive function with increasing age. Such decline has been attributed to cross-sectional cohort effects, the effects of stress and intercurrent medical illness, as well as age per se (Botwinick, 1977; Eisdorfer & Wilkie, 1977). We studied the relationship between psychopathology and cognitive functioning in two groups of elderly people, 115 elderly psychiatric outpatients (M age and SD, 71.48 yr. and 6.05 yr.) and 213 symptomatic volunteers (M 3ge and SD, 70.08 yr. and 5.25 yr.). The symptomatic volunteers mere senior citizen club members living in the community who were not psychiauic patients but who complained of substantial memory problems. Both groups lived in the same geographical area; and ages and sex were comparably distributed. The Conceprual Level Analogy Test, a multiple-choice analogy rest which assesses
Review of ultrashort pulse measurement: changing the basic ultrashort pulse experiment

Until recently, experiments in ultrashort pulse science have involved measuring the spectrum and autocorrelation of the input pulse(s) and only measuring the integrated energy or perhaps time-resolved energy of the output signal. These experiments ignored the information contained in the input and output pulse phases and intensity profiles. New pulse measurement techniques such as frequency-resolved optical grating, when combined with older techniques such as spectral interferometry, now allow the complete characterization of the pulses. These techniques allow measurements of the intensity, phase, and polarization state of ultrashort pulses as functions of time (or frequency) and space. These techniques work for wavelengths from the UV to the IR and for extremely weak pulses and very high power pulses. They also allow entirely new classes of experiments for measuring ultrafast phenomena. Now the phases and temporal profiles of the input pulses may be measured and controlled, and the intensity and phase of the output pulses can also be measured. These new measurement techniques have thus greatly increased the obtainable information in ultrafast experiments. This paper reviews current pulse measurement methods including frequency-resolved optical grating and spectral interferometry and describes how they are changing the way that ultrashort pulse experiments are performed.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
VIII. What Systems Can Be Studied, Have Been Studied, and Should Be Studied?

The status of charge density studies is reviewed with special emphasis on factors limiting its potential, on a priori estimates of position-dependent standard deviations and on present and possible future applications of the method.
Sustained drug delivery systems II: Factors affecting release rates from poly(ε‐caprolactone) and related biodegradable polyesters

The release rates of several steroids from films and capsules of homopolymers and copolymers of e-caprolactone, DL-lactic acid, and glycolic acid were measured in vitro and in vivo for up to 200 days. Relatively constant release rates from capsules (reservoir devices) were observed only under certain conditions. Factors that influence the drug release kinetics were evaluated. Release from poly(e-caprolactone) and poly(e-caprolactone-co-DL-lactic acid) was diffusion controlled. Release from poly(DL-lactic acid-co-glycolic acid) was associated with polymer degradation. Release from poly(DL-lactic acid) was very slow when diffusion controlled.
A Dynamic Attenuator Improves Spectral Imaging With Energy-Discriminating, Photon Counting Detectors

Energy-discriminating, photon counting (EDPC) detectors have high potential in spectral imaging applications but exhibit degraded performance when the incident count rate approaches or exceeds the characteristic count rate of the detector. In order to reduce the requirements on the detector, we explore the strategy of modulating the X-ray flux field using a recently proposed dynamic, piecewise-linear attenuator. A previous paper studied this modulation for photon counting detectors but did not explore the impact on spectral applications. In this work, we modeled detection with a bipolar triangular pulse shape (Taguchi , 2011) and estimated the Cramer-Rao lower bound (CRLB) of the variance of material selective and equivalent monoenergetic images, assuming deterministic errors at high flux could be corrected. We compared different materials for the dynamic attenuator and found that rare earth elements, such as erbium, outperformed previously proposed materials such as iron in spectral imaging. The redistribution of flux reduces the variance or dose, consistent with previous studies on benefits with conventional detectors. Numerical simulations based on DICOM datasets were used to assess the impact of the dynamic attenuator for detectors with several different characteristic count rates. The dynamic attenuator reduced the peak incident count rate by a factor of 4 in the thorax and 44 in the pelvis, and a 10 Mcps/mm $^{2}$ EDPC detector with dynamic attenuator provided generally superior image quality to a 100 Mcps/mm $^{2}$ detector with reference bowtie filter for the same dose. The improvement is more pronounced in the material images.
Differential expression of type I collagen and cellular fibronectin isoforms in endothelial cell variants.

Differential expression of type I collagen and cellular fibronectin isoforms in endothelial cell variants. Endothelial cells in vivo and in vitro are inherently capable of manifesting more than one phenotype. Most endothelial cells in culture, even when maintained at confluent density for an extended period, exhibit only the typical polygonal morphology. Other cultures, albeit few, are characterized by rapid formation of variant "sprout" cells once the cobblestone monolayer is established. In vivo studies have revealed sprout cell formation to be one of the early events in neovascularization. Therefore, elucidation of the factors involved in this process is needed to gain an understanding of the sprouting phenomena. To this end, two morphologically distinct bovine endothelial cell clones derived from a fetal left ventricle were characterized. One culture of cells stably displayed the conventional polygonal phenotype, in contrast to the second culture in which an interconnecting network of sprout cells reproducibly developed beneath the cobblestone monolayer. Analysis of extracellular matrix proteins and RNA transcripts revealed that the sprouting clone showed induction of type I collagen and a shift in fibronectin RNA processing resulting in synthesis of the cellular isoforms. These collagenous and non-collagenous matrix molecules may serve in some manner to affect the processes required during angiogenesis, that is, cell division, cell migration and cell shape change.
Ethical considerations in mass communications research

Mass communication researchers face ethical dilemmas during the course of their work, and those dilemmas are more than the trilogy of informed consent, deception, and privacy. As part of a project for the Association for Education in Journalism and Mass Communication, we surveyed members of the association's Communication Theory and Methodology Division. Researchers, in an open‐ended question at the end of the survey, said their concerns about ethics in research ranged from journal publication practices to proprietary research.
Foliar absorption — penetration of the cuticular membrane and nutrient uptake by isolated leaf cells

Foliar absorption consists of penetration of a cuticular membrane and uptake by living cells within the leaf. A detailed analysis of nutrient absorption by these two systems has revealed that ionic penetration of the cuticular membrane is by diffusion, and that the coupling between active transport and metabolism is at the cellular level. Urea penetrates the cuticular membrane and is absorbed by leaf cells much more rapidly than are nutrient ions. Furthermore, urea facilitates penetration and absorption of other materials simultaneously applied. Penetration of nutrient ions through cuticular membranes has been localized by microautoradiography as occurring around stomatal pores and along periclinal cell walls. Chelation of metals such as iron, manganese and zinc reduces the rate of foliar absorption, but increases the translocation of the absorbed nutrient. At the cellular level the nutrient ion is absorbed and the ligand is excluded.
Time to remission and relapse after the first hospital admission in severe bipolar disorder

Few studies of the time to remission and first relapse in severe bipolar disorder have been based on epidemiologically defined samples or have examined patient characteristics and time-varying indicators of medication use simultaneously. Using a cohort from the Suffolk County Mental Health Project, we describe these temporal patterns and their relationships with childhood, illness, and treatment characteristics. A multi-facility cohort of 123 first-admission inpatients with DSM-IV bipolar disorder with psychotic features was followed for 4 years. Dates of the first complete remission (lasting at least 2 months), subsequent relapses, and use of antimanic (AM),antipsychotic (AP), and antidepressant (AD) medications were recorded. Childhood and illness characteristics were ascertained at baseline using standard instruments. By the 4-year point, 83.7% had achieved a full remission, with 42.3% remitting within 3 months, 63.4% within 6 months, and 74.8% within 1 year. Overall, younger age of onset, history of childhood psychopathology, and higher Brief Psychiatric Rating Scale (BPRS) anxiety/depression scores were significantly associated with longer time to remission. Discontinuing AM, AP and AD (compared to never using) and taking AP and AD (compared to never using) were significantly associated with remission in the multivariate analysis. Of the 103 participants with complete remission, 61.2% suffered a relapse; 24.3 % relapsed within 6 months of remission, and 35.9% within a year. Overall, 32.5% of the 123 participants had a single episode followed by full remission. Childhood internalizing-type problems, higher BPRS anxiety/depression and Hamilton depression scores, and an admission episode not involving mania, but not patterns of medication use, were associated with shorter time to relapse. By 4-year follow-up, the majority of severely ill bipolar patients had remitted from their initial episode, but more than half subsequently relapsed. Illness characteristics, especially depressive symptoms, and medication treatment were associated with the early course, although medication use after remission was not associated with relapse.
Reflective and Electrically Conductive Surface Silvered Polyimide Films and Coatings Prepared via Unusual Single-Stage Self-Metallization Techniques

Highly reflective and/or surface conductive flexible polyimide films can be prepared by the incorporation of positive valent silver compounds into solutions of poly(amic acid)s formed from a variety of dianhydrides and diamines. Thermal curing of selected silver(I)-containing poly(amic acid)s leads to cycloimidization of the polyimide precursor with concomitant silver(I) reduction and surface aggregation of the metal yielding a reflective and/or conductive silver surface similar to that of the native metal. However, not all silver(I) precursors are effective surface metallization agents and not all poly(amic acid)s metallize with equal facility. Ligand/anion and polyimide structural effects on film metallization efficacy and on physical properties on metallized films are reviewed.
Epistemology in the face of strong sociology of knowledge

Advocates of the strong programme in the sociology of knowledge contend that its four defining tenets entail the elimination and replacement tout court of epistemology by strong sociology of knowledge. I advance a naturalistic conception of both substantive and meta-level epistemological inquiry which fully complies with these four tenets and thereby shows that the strong programme neither entails nor even augurs the demise of epistemology.
Influence of proliferation on DNA repair rates in liver.

Abstract To test the hypothesis that the proliferative status of a mammalian cell determines the rate of removal of oxidative DNA damage, pre- and posthepatectomized livers in adult male Fisher 344 rats were irradiated in situ with 15.5 Gy of 137Cs γ-rays. At 10 and 45 min after irradiation, the livers were removed and dissociated into single cell suspensions, and the DNA damage in the isolated quiescent or proliferative liver cells was assayed by alkaline elution. Proliferative liver cells irradiated 20–24 h or 29–31 h after hepatectomy repaired their DNA damage faster than quiescent liver cells. A corresponding increase in the accessibility of the DNA to digestion by m. nuclease was observed for the posthepatectomized liver cells. These data suggest that proliferative status is a major determinant of the rate of DNA repair in rat liver.
Mechanistic studies of postcapillary affinity detection for capillary zone electrophoresis based on the biotin-streptavidin system

Postcapillary affinity detection is developed to analyze structurally related compounds following capillary zone electrophoresis separation. In this work, biotin and biotin derivatives are resolved by capillary zone electrophoresis and selectively identified on the basis of their cross-reactivity with streptavidin−fluorescein isothiocyanate, added via a postcapillary reactor. Direct sensing of the affinity reaction is achieved by monitoring the resulting fluorescence enhancement of streptavidin−fluorescein isothiocyanate upon biotin binding. The effects of postcapillary reactor parameters, including capillary gap distance, dilution ratio, and reaction distance, on peak area and peak efficiency of the biotin−streptavidin complex are investigated. A reaction kinetic model is presented for evaluating the dynamic range and detection limits of postcapillary affinity detection as a function of streptavidin concentration in the postcapillary reactor. The detection limit for postcapillary affinity detection of bi...
Two-photon excited fluorescence from biological aerosol particles

Abstract We used a 40 MHz mode-locked 524 nm laser source to evaluate the utility of sub-picosecond excitation of fluorescence from 2-photon absorption in biological aerosols. Individual particles of biological composition, as well as other calibration particles, suspended in an inlet air flow were illuminated and measured as they passed through an optical chamber. To our knowledge, this was the first demonstration of 2-photon excited fluorescence from micron-sized particles composed of micro-organisms. We also observed a high fluorescence signal at visible wavelengths, which was not present with single-photon excitation.
Mismatch repair deficient human cells: spontaneous and MNNG-induced mutational spectra in the HPRT gene.

We have determined both the spontaneous and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced mutational spectra in the HPRT gene of human cells (MT1) defective in the mismatch repair gene hMSH6 (GTBP). Eight of nine exons and nine of sixteen intronic flanking sequences were scanned, encompassing >900 bp of the HPRT gene. Mutant hotspots were detected and separated by differences in their melting temperatures using constant denaturant capillary electrophoresis (CDCE) or denaturing gradient gel electrophoresis (DGGE).A key finding of this work is that a high proportion of all HPRT inactivating mutations is represented by a small number of hotspots distributed over the exons and mRNA splice sites. Thirteen spontaneous hotspots and sixteen MNNG-induced hotspots accounted for 55% and 48% of all 6TG(R) point mutations, respectively. MNNG-induced hotspots were predominantly G:C-->A:T transitions. The spontaneous spectrum of cells deficient in hMSH6 contained transversions (A:T-->T:A, G:C-->T:A, A:T-->C:G), transitions (A:T-->G:C), a plus-one insertion, and a minus-one deletion. Curiously, G:C-->A:T transitions, which dominate human germinal and somatic point mutations were absent from the spontaneous hMSH6 spectra.
Safety and efficacy of erythropoietin in children with chronic renal failure

A prospective randomized study of the use of recombinant human erythropoietin (rHuEPO) in children with chronic renal disease was conducted to assess dosing requirements and side effects. Forty-four children with chronic renal failure, aged 4 months to 21 years, were studied. Twenty-five patients were pre dialysis, 10 on peritoneal dialysis, and 9 on hemodialysis. Patients received either 150 U/kg per week or 450 U/kg per week divided thrice weekly of rHuEPO for 12 weeks or until target hemoglobin (Hb) was attained. Dose was then adjusted to maintain a normal Hb. Eighty-two percent of patients reached target Hb by 7.9±5.6 weeks (mean±SD); 95% of patients in the high-dose group and 66% in the low-dose group reached target Hb within 12 weeks. The overall median rHuEPO dose at target Hb was 150 U/kg per week. Hemodialysis patients tended to require more rHuEPO to maintain a normal Hb (median 250 U/kg per week). Transfusion requirements and panel-reactive antibody levels decreased during the 12 weeks. Iron deficiency and/or hypertension occurred in 30% of children. In conclusion, rHuEPO at 150 U/kg per week is safe and effective in treating anemia in children with chronic renal disease.
Duodenal perforation: a complication of neonatal nasojejunal feeding.

NASOJEJUNAL alimentation has recently become an attractive alternative method for feeding sick newborn infants. Bypassing the stomach minimizes the possibility of regurgitation and aspiration. The continuous infusion of formula into the proximal jejunum also appears to be a safer, more physiologic approach to infant nutrition than intravenous hyperalimentatio n. The complications of intravenous alimentation are well known. The problems associated with nasojejunal feedings have been less well described. The following report relates a logically expected but previously unreported complication of nasojejunal alimentation.
Phenomenological Λ-Nucleon Potentials from s-Shell Hypernuclei. II. Dependence on Intrinsic Range

By examining the binding-energy data of the $s$-shell hypernuclei and the $\ensuremath{\Lambda}$-proton scattering data with a number of effective central $\ensuremath{\Lambda}$-nucleon potentials of various hard-core radii (0-0.6 F) and intrinsic ranges (1.5-2.5 F), a $\ensuremath{\Lambda}$-nucleon potential has been found which yields a very good fit to these experimental data. This potential has an intrinsic range of 2.1 F, a hard-core radius of 0.6 F, and an odd-parity-state strength which is equal to 60% of the even-parity-state strength. Also, it has a rather small degree of spin dependence in the $\ensuremath{\Lambda}$-proton case, with the consequence that the predicted $J=1$ excited state in $_{\ensuremath{\Lambda}}\mathrm{H}^{4}$ has a small excitation energy of only about 0.1 MeV. The $\ensuremath{\Lambda}$-proton effective-range parameters have the following values: ${{a}_{t}}^{p}=\ensuremath{-}2.08$ F, ${{r}_{0t}}^{p}=3.40$ F, ${{a}_{s}}^{p}=\ensuremath{-}2.25$ F, and ${{r}_{0s}}^{p}=3.29$ F. The case of $\ensuremath{\Lambda}$-neutron scattering has also been considered. Here it is found that the total cross sections differ appreciably from those of the corresponding $\ensuremath{\Lambda}$-proton case only when the c.m. energy is less than about 4 MeV.
Conductance of Connexin Hemichannels Segregates with the First Transmembrane Segment

Gap junction channels are intercellular channels that mediate the gated transfer of molecules between adjacent cells. To identify the domain determining channel conductance, the first transmembrane segment (M1) was reciprocally exchanged between Cx46 and Cx32E143. The resulting chimeras exhibited conductances similar to that of the respective M1 donor. Furthermore, a chimera with the carboxy-terminal half of M1 in Cx46 replaced by that of Cx32 exhibited a conductance similar to that of Cx32E143, whereas the chimera with only the amino-terminal half of M1 replaced retained the unitary conductance of wild-type Cx46. Extending the M1 domain swapping to other connexins by replacing the carboxy-terminal half of M1 in Cx46 with that of Cx37 yielded a chimera channel with increased unitary conductance close to that of Cx37. Furthermore, a point mutant of Cx46, with leucine substituted by glycine in position 35, displayed a conductance much larger than that of the wild type. Thus, the M1 segment, especially the second half, contains important determinants of conductance of the connexin channel.