cssi/SciSciGPT-SciSciNet huggingface dataset:
Biochemical synthesis of electroactive polymers

Horseradish peroxidase catalyzed oxidative free radical coupling of phenols and anilines has been utilized in the synthesis of soluble polymers with interesting electronic and optical properties. The main chain azopolymers synthesized by this method are soluble in polar solvents and undergo cis-trans isomerization upon exposure to light. The photoinduced conformational changes in the polymers are influenced by the molecular weight of the polymer. Water soluble polyanilines have been synthesized by polymerizing monomers containing polar functional groups. These polymers are reversible redox systems and show interesting optical properties, which are dependent on the solution pH. A polymeric ligand has been synthesized following this reaction, which may be used in the fabrication of metal ion sensors. We further describe the potential of these polymers in sensing and other related applications.
Sample size determination under an exponential model in the presence of a confounder and type I censoring.

Abstract In controlled clinical trials, random assignment of treatments to individuals is usually used to eliminate the effects of confounding variables. When there is censorship in data, however, confounding effects may not be automatically removed solely by random assignment of treatments to individuals under the exponential model. Therefore, it is important to incorporate the confounding effect into the sample size calculation even after randomization of treatments to individuals. In this paper, the discussion is restrictred only to the situation where there are two comparison groups and one single Bernoulli confounding variable. Based on an exponential covariate model, an explicit sample size formula considering the confounding effect has been derived for the design of trials with type I censoring, in which an end time is fixed in advance and all responses occurring after that time are censored. The resulting sample size formula can also be applied to nonrandomized clinical trials. Finally, to provide insight into the influence of different factors on sample size calculation, a discussion on the effects of treatments, the confounder, the length of follow-up times for studied individuals, and the joint distribution of the treatment and the confounder has been included.
Rapid Release of Entrapped Contents from Multi-Functionalizable, Surface Cross-Linked Micelles upon Different Stimulation

Hydrophobic guests such as pyrene could be readily trapped inside the micelles of an alkynylated surfactant in the presence of an azide-functionalized cross-linker using the click reaction. The cross-linker was designed to contain cleavable bonds such as geminal diol, disulfide, and acetal. The resulting pyrene-containing water-soluble nanoparticle was under electrostatic stress when diluted below the CMC of the surfactant. Extremely rapid (<1 min) release of the hydrophobic content was observed when the cross-linker was cleaved. This method combines the ease of physical entrapment and the precision of chemical ligation, and potentially is highly useful in the delivery and controlled release of pharmaceutical agents.
Dielectric Breakdown and Charge Trapping of Ultrathin ZrHfO/SiON High-$k$ Gate Stacks

One- and two-step breakdown phenomena were observed on the zirconium-doped hafnium oxide (ZrHfO) high-k dielectric films with equivalent oxide thicknesses 1.8 and 2.5 nm, respectively. The difference in the breakdown sequence was attributed to the bulk high-k layer thickness and interface layer structure. The trap generation and charge trapping in the high-k stack was investigated using a new stress–relax method through analyzing the relaxation current change. The results showed that new traps were only created under the high bias condition and the density could be comparable to or even larger than that of the preexisted traps.
Estrogen enhances attachment of Chlamydia trachomatis to human endometrial epithelial cells in vitro.

Ultraviolet light-inactivated elementary bodies of Chlamydia trachomatis serovar E were fluorescently tagged with rhodamine isothiocyanate (5 μg/ml) and added to primary cultures of human endometrial gland epithelial cells. The elementary bodies, at a multiplicity of infection of 600:1, were allowed to adsorb to the cell monolayers for 1 hour at 35° C in an atmosphere of 5% carbon dioxide. The monolayers were disaggregated by trypsinization and the individual cells were processed in the fluorescent activated cell sorter for chlamydial attachment . This method of analysis revealed attachment of C. trachomatis to approximately 50% of human endometrial gland epithelial cells. Addition of estrogen (10 -10 mol/L) to the culture medium enhanced chlamydial attachment to human endometrial gland epithelial cells to approximately 80% ( p ⩽ 0.005), and progesterone in combination with estrogen reduced chlamydial attachment in a dose-dependent fashion: 1 ng/ml progesterone, approximately 50%; 5 ng/ml, about 30%; 10 ng/ml, about 18%, respectively ( p ⩽ 0.025).
Effects of ambient levels of solar ultraviolet radiation on zooxanthellae and photosynthesis of the reef coral Montipora verrucosa

Paired flat plates of the hermatypic coral Montipora verrucosa from Kaneohe Bay, Oahu, Hawaii, were acclimated to photosynthetically active radiation (PAR) only and to full sunlight (PAR+UV) for several weeks in the summer of 1990. After the acclimation period, photosynthesis, both in PAR-only and PAR+UV as well as dark respiration were measured. Levels of the UV-absorbing compounds, “S320”, density of zooxanthellae, and chlorophyll a concentration were determined. Corals acclimated in PAR+UV had higher levels of the UV-protective compounds and lower areal zooxanthellae densities than corals acclimated in PAR-only. Chlorophyll a per unit volume of coral host and per algal cell did not differ between corals from the two acclimation treatments. Corals acclimated to PAR+UV displayed higher photosynthesis in full sunlight than corals acclimated to PAR-only, but when photosynthesis was measured in the light regime to which the corals had been acclimated, there were no differences in photosynthesis. Dark respiration was the same for corals from the two acclimation treatments regardless of the light quality immediately preceding the dark period.
A 454 sequencing approach to dipteran mitochondrial genome research

The availability of complete mitochondrial genome (mtgenome) data for Diptera, one of the largest metazoan orders, in public databases is limited. The advent of high throughput sequencing technology provides the potential to generate mtgenomes for many species affordably and quickly. However, these technologies need to be validated for dipterans as the members of this clade play important economic and research roles. Illumina and 454 sequencing platforms are widely used in genomic research involving non-model organisms. The Illumina platform has already been utilized for generating mitochondrial genomes without using conventional long range PCR for insects whereas the power of 454 sequencing for generating mitochondrial genome drafts without PCR has not yet been validated for insects. Thus, this study examines the utility of 454 sequencing approach for dipteran mtgenomic research. We generated complete or nearly complete mitochondrial genomes for Cochliomyia hominivorax, Haematobia irritans, Phormia regina and Sarcophaga crassipalpis using a 454 sequencing approach. Comparisons between newly obtained and existing assemblies for C. hominivorax and H. irritans revealed no major discrepancies and verified the utility of 454 sequencing for dipteran mitochondrial genomes. We also report the complete mitochondrial sequences for two forensically important flies, P. regina and S. crassipalpis, which could be used to provide useful information to legal personnel. Comparative analyses revealed that dipterans follow similar codon usage and nucleotide biases that could be due to mutational and selection pressures. This study illustrates the utility of 454 sequencing to obtain complete mitochondrial genomes for dipterans without the aid of conventional molecular techniques such as PCR and cloning and validates this method of mtgenome sequencing in arthropods.
Molecular markers for marine algal polysaccharides

Alginate, carrageenan and agar are marine algal polysaccharides with several common features. They all contain linear substructures which enable them to form gels. All three types of polymers vary within and between samples in subunit composition and arrangement, and in molecular weight. That the subunit organization in these complex algal polymers is neither completely regular nor completely random is becoming increasingly clear (Larsen, 1981; Greer et al., 1984). The relationship between carbohydrate primary structure, polymer conformation and biochemical properties of marine algal carbohydrates is gaining increasing attention as new experimental approaches are being developed. Recent studies have involved combinations of chemical or enzymatic fragmentation; size, ionic or electrophoretic separations; and analysis of polymer properties or interactions by nuclear magnetic resonance spectroscopy, infrared spectroscopy, optical rotatory dispersion, circular dichroism, light scattering, calorimetry and other modern techniques (e.g., Dea et al., 1972; Larsen, 1981; Smidsrod & Grasdalen, 1984; Lahaye et al., 1985).
Discrimination of third-order Markov constraints within visual displays

Discrimination thresholds were measured for third-order Markov constraints within visual displays. The method permits the cancellation of adjacent second-order differences and of first-order differences. Excellent discrimination of third-order constraints is obtained despite the fact that the average conditional repetition probability and the average run length were invariant. The need to distinguish between local short-term and average long-term analyses for the visual system is briefly discussed.
Technique to Facilitate Mitral Valve Exposure

Abstract We describe a technique to facilitate mitral valve exposure by mobilizing the superior and inferior venae cavae. The intrapericardial cavae are encircled by a cuff of pericardium, which can be freed circumferentially for 4 to 5 cm on the superior vena cava and 2 to 3 cm on the inferior vena cava. This maneuver allows for extensive retraction and elevation of the right atrium and venae cavae, thereby making exposure of the mitral valve much easier, even in those patients with a small atrium.
Transnational pathways and politico-economic power: Globalisation and the lebanese civil war

Celebrants of neo-liberal globalisation and their critics ascribe to the rationality of finance capital enormous power. It opens new territories, produces new cultural forms and creates a hierarchy of cities and the spaces within them. How might this image change when viewed from spaces allegedly excluded from capitalist globalisation? For many, Lebanon during its 1975–1990 civil war was such a place. The international financial institutions and their Lebanese allies presented neo-liberal reform as the necessary prerequisite for post-conflict re-integration with rational processes of capitalist globalisation. Through a multi-sited political economy of one financial network operant in wartime Lebanon, I show that the “militia economy” was never outside larger processes of financial globalisation. I argue that it was integrated into a global realm consisting not of financial corporations operating according to a universal capitalist rationality, but rather one of similarly constituted networks of capitalist...
Dimensional changes during solvent-induced crystallization of poly(ethylene terephthalate) films

The sample dimensional changes accompanying diffusion with induced crystallization in amorphous poly(ethylene terephthalate) (PET) films are analyzed. Initially, the film's lateral area remains practically constant, but near the end of the process, it increases rapidly, consistent with non-Fickian models for diffusion. The ultimate relative thickness increase is about double that for the lateral dimension, implying that plastic deformation in the thickness direction accompanies the sorption. Plots of fractional area increase (ΔA/ΔA∞) vs. fractional weight gain (W/W∞) indicate severe softening of the polymer by the penetrant.
Comparison of arsenic, cadmium, chromium, lead, manganese, mercury and selenium in feathers in bald eagle (Haliaeetus leucocephalus), and comparison with common eider (Somateria mollissima), glaucous-winged gull (Larus glaucescens), pigeon guillemot (Cepphus columba), and tufted puffin (Fratercula cirrhata) from the Aleutian Chain of Alaska

There is an abundance of field data for levels of metals from a range of places, but relatively few from the North Pacific Ocean and Bering Sea. In this paper we examine the levels of arsenic, cadmium, chromium, lead, manganese, mercury and selenium in feathers from common eiders (Somateria mollissima), glaucous-winged gulls (Larus glaucescens), pigeon guillemots (Cepphus columba), tufted puffins (Fratercula cirrhata) and bald eagles (Haliaeetus leucocephalus) from the Aleutian Chain of Alaska. Our primary objective was to test the hypothesis that there are no trophic levels relationships for arsenic, cadmium, chromium, lead, manganese, mercury and selenium among these five species of birds breeding in the marine environment of the Aleutians. There were significant interspecific differences in all metal levels. As predicted bald eagles had the highest levels of arsenic, chromium, lead, and manganese, but puffins had the highest levels of selenium, and pigeon guillemot had higher levels of mercury than eagles (although the differences were not significant). Common eiders, at the lowest trophic level had the lowest levels of some metals (chromium, mercury and selenium). However, eiders had higher levels than all other species (except eagles) for arsenic, cadmium, lead, and manganese. Levels of lead were higher in breast than in wing feathers of bald eagles. Except for lead, there were no significant differences in metal levels in feathers of bald eagles nesting on Adak and Amchitka Island; lead was higher on Adak than Amchitka. Eagle chicks tended to have lower levels of manganese than older eagles.
Evaluating the outcomes of developmental education

Developmental education programs can use innovative ways to improve minority learning and persistence.
Urinary excretion of prostaglandin E like material and kallikrein: Effects of furosemide

Abstract In a controlled study of 11 women, 5 with mild essential hypertension and 6 normal volunteers, furosemide produced a significant natriuresis and diuresis without changes in the urinary excretion of prostaglandin E-like material and kallikrein. Therefore, although some evidence in man or animals suggests involvement of both of these substances in renal responses to furosemide, the present data suggest that the natriuretic and diuretic effects of this drug are not associated with an increased excretion of prostaglandin E like material or kallikrein.
Seven systematic reviews confirm topical fluoride therapy is effective in preventing dental caries

Abstract Original Articles 1.Marinho VCC, Higgins JPT, Logan S, Sheiham A. Fluoride toothpastes for preventing dental caries in children and adolescents (Cochrane Review). In: The Cochrane Library, Issue 1, 2004. Chichester, UK: John Wiley & Sons, Ltd. (Date of most recent substantive amendment: 13 September 2002) 2.Marinho VCC, Higgins JPT, Logan S, Sheiham A. Fluoride mouthrinses for preventing dental caries in children and adolescents (Cochrane Review). In: The Cochrane Library, Issue 1, 2004. Chichester, UK: John Wiley & Sons, Ltd. (Date of most recent substantive amendment: 19 May 2003) 3.Marinho VCC, Higgins JPT, Logan S, Sheiham A. Fluoride gels for preventing dental caries in children and adolescents (Cochrane Review). In: The Cochrane Library, Issue 1, 2004. Chichester, UK: John Wiley & Sons, Ltd. (Date of most recent substantive amendment: 27 September 2001) 4.Marinho VCC, Higgins JPT, Logan S, Sheiham A. Fluoride varnishes for preventing dental caries in children and adolescents (Cochrane Review). In: The Cochrane Library, Issue 1, 2004. Chichester, UK: John Wiley & Sons, Ltd. (Date of most recent substantive amendment: 26 November 2001) 5.Marinho VCC, Higgins JPT, Logan S, Sheiham A. Topical fluoride (toothpastes, mouthrinses, gels or varnishes) for preventing dental caries in children and adolescents (Cochrane Review). In: The Cochrane Library, Issue 1, 2004. Chichester, UK: John Wiley & Sons, Ltd. (Date of most recent substantive amendment: 20 August 2003) 6.Marinho VCC, Higgins JPT, Sheiham A, Logan S. One topical fluoride (toothpastes, or mouthrinses, or gels, or varnishes) versus another for preventing dental caries in children and adolescents (Cochrane Review). In: The Cochrane Library, Issue 1, 2004. Chichester, UK: John Wiley & Sons, Ltd. (Date of most recent substantive amendment: 24 November 2003) 7.Marinho VCC, Higgins JPT, Sheiham A, Logan S. Combinations of topical fluoride (toothpastes, mouthrinses, gels, varnishes) versus single topical fluoride for preventing dental caries in children and adolescents (Cochrane Review). In: The Cochrane Library, Issue 1, 2004. Chichester, UK: John Wiley & Sons, Ltd. (Date of most recent substantive amendment: 25 November 2003). Level of Evidence 1A Purpose To determine and compare the effectiveness and safety of fluoride varnishes, gels, mouthrinses, and toothpastes when used individually and in combinations. Source of Funding CAPES – Ministry of Education, Brazil Department of Epidemiology and Public Health, University College London, UK Systematic Reviews Training Unit, Institute of Child Health, University College London, UK Medical Research Council, UK Authors report no known conflicts of interest Type of Study/Design Systematic reviews with meta-analysis
Role of two outer membrane antigens in the induction of protective immunity against Francisella tularensis strains of different virulence

A crude outer membrane preparation from Francisella tularensis live vaccine strain was used to immunise mice. Immunised mice were completely protected from a F. tularensis challenge. We evaluated the role of two major outer membrane antigens in the induction of protective immunity, namely lipopolysaccharide and an outer membrane protein FopA. We presented FopA to the immune system using an aromatic amino acid dependent Salmonella typhimurium as a vector. Although mice mounted an immune response to cloned FopA no significant protection was induced. However, lipopolysaccharide-immunised mice were completely protected from a F. tularensis live vaccine strain challenge. No increase in LD50 was observed using F. tularensis Schu4 as the challenge strain, although there was a significant increase in time to death. These data question the validity of the murine F. tularensis live vaccine strain model.
Heterotypic cellular interactions in the ovarian tumor microenvironment: biological significance and therapeutic implications.

The majority of women who are diagnosed with epithelial ovarian cancer present with extensive peritoneal carcinomatosis and are rarely cured by conventional chemotherapy. Ovarian cancer cells typically disseminate by shedding into the peritoneal fluid and implant on the mesothelium-lined peritoneal surfaces that overlie connective and white adipose tissues. Emerging evidence indicates that ovarian tumor progression is orchestrated by dynamic interplay between tumor cells and a variety of stromal cells such as adipocytes, endothelial cells, fibroblasts, mesenchymal stem cells, macrophages and other immune cells. This mini-review discusses the biological significance of the heterotypic cellular interactions in the ovarian tumor microenvironment and the therapeutic implications of targeting these interactions.
Spatially explicit individual-based modeling using a fixed super-individual density

Individual-based models (IBMs) of planktonic microorganisms (e.g., bacterioplankton, phytoplankton) have to simulate large numbers of individuals. Because of computational limitations these models rely on simulating a number of super-individuals that are representative of a larger number of individuals. Using a fixed representative number (the number of individuals one super-individual represents) results in a lower computational resolution (number of super-individuals) at times and in areas of low individual densities, which is undesirable when (a) large temporal and/or spatial gradients exist and (b) variability in state variables or behavior at low densities is important. Various methods exist that fix the number of super-individuals in the global model domain by allowing the representative number to vary in time. Those methods solve the problem introduced by large temporal gradients, but do not address spatial gradients. This paper presents an accounting method that maintains an approximately constant super-individual density in time and space. Each spatial model segment has a local super-individual population that is resampled when the number shrinks or grows outside user-specified bounds, or when the variance of the representative numbers exceeds a user-specified threshold. This local method is compared to a global method and evaluated quantitatively against the analytical solution to an instantaneous input (slug release) into a river, and qualitatively in a biogeochemical phytoplankton model applied to a point source nutrient discharge into a river. Computations are performed using the iAlgae individual-based phytoplankton modeling framework. The applications demonstrate that the local method results in a spatially uniform or density-independent relative error, and it is computationally more efficient at controlling relative error at low densities. However, for the same total number of super-individuals, it is computationally more demanding and therefore less efficient at controlling absolute error. The local method is superior to the global method for the biogeochemical model application, because a significant spatial gradient (front) exists and the dynamics at the low densities affects the model behavior downstream.
Die Atomsynthese, die sich in Begleitung von Atomspaltung (Atomzertrümmerung) kundgibt, und die Theorie vom Aufbau der Atome aus Wasserstoff und Helium

Im Jahre 1923 veroffentlichten Harkins und Ryan eine Methode zum Studium des Zerfallsmechanismus von Stickstoff und von anderen Elementen mit leichten Atomen, die in Gasform erhaltlich sind. Die Methode bestand in der Photographie einer auserordentlich grosen Menge von Wilsonschen Nebelbahnen, wie sie in dem Gase durch die Verwendung auserst schneller α-Partikeln erzeugt werden. Aus 11 000 Photographien, die von ihnen, und 34 000, die von uns aufgenommen worden sind, ergaben sich zwei Falle, in denen sich eine α-Partikel mit dem Kerne eines Stickstoffatoms verbindet, womit die Ausstosung eines Protons unmittelbar verknupft ist. Die direkte Vereinigung einer α-Partikel mit dem Kerne eines Atoms ist im Einklang mit der Theorie vom Wasserstoff-Helium-Aufbau der Atome, die seit 1915 in einer Reihe von Publikationen veroffentlicht worden ist. Es ist diese Theorie, welche zur Entdeckung der folgenden Beziehung gefuhrt hat: Die Stabilitat sowohl als auch die Haufigkeit des Vorkommens von Atomen und ebenfalls die Zahl der Atomarten sind samtlich im allgemeinen viel hoher fur die geradzahligen als fur die ungeradzahligen Werte 1. der Ordnungszahl Z, 2. der Zahl N der im Kern enthaltenen negativen Elektronen, 3. der Zahl P der positiven Elektronen im Kern und 4. der Isotopenziffer (n=N-Z). Es wird nun gezeigt, das neue Arbeiten uber die Stabilitat der leichten Elemente, uber den Packeffekt in leichten Elementen und uber die Zusammensetzung der Isotopen samtlich diese Regel bestatigen und auch beweisen, das sie weit allgemeiner und wichtiger ist als mit den vor zehn Jahren zur Verfugung stehenden Daten dargelegt werden konnte.
Detection of Isoflavones in Seedling Subterranean Clover

Reproductive disorders in sheep (Ovis aries) have been linked to ingestion of subterranean clovers (Trifolium brachycalycinum Katzn. & Morley, T. subterraneum L., and T. yanninicum Katzn. & Morley) containing high levels of the phytoestrogenic isoflavones formononetin (7-hydroxy-4-methoxyisoflavone; FM), genistein (5,7,4-trihydroxyisoflavone; GE), and biochanin A (5,7-dihydroxy-4-methoxyisoflavone; BA)
Bilateral internal jugular vein thrombosis

The incidence of head and neck thrombosis is rare and accounts for less than 5% of deep vein thrombosis [1]. Before the introduction of antibiotics, the most common cause of internal jugular vein thrombosis was oropharyngeal infection [2, 3]. At present, intravenous drug abuse and central venous catheterization are the most common contributors [2, 3]. The authors report a case of bilateral internal jugular vein thrombosis associated with metastatic colon cancer and history of multiple percutaneous cannulation of the internal jugular veins.
The unique contribution of peers to socialization in early childhood

(1981). The unique contribution of peers to socialization in early childhood. Theory Into Practice: Vol. 20, Early Education: Child and Context, pp. 105-108.
Staking a Claim on Learning: What We Should Know about Learning in Higher Education and Why.

Researchers can deepen investigations of college teaching and learning by attention on how students construe a lesson’s subject matter and on how teachers make sense of and respond to their students’ subject-matter thinking in the moment. While it is possible to examine teaching and learning minus subject-matter depth, doing so obscures the dynamics that define education. My illustrative example captures teaching and learning about the idea of Cartesian doubt in an introductory philosophy class. I analyze students’ struggles with this new (and to most, startling) idea in light of their prior knowledge. I also examine the instructor’s efforts to grasp and respond to students’ evolving conceptions of Cartesian doubt.
Animal models of occupational asthma

Occupational asthma is characterized by variable airflow obstruction occurring in the workplace. The presence of airways inflammation and hyperreactivity provides further evidence for the disease. Since its pathogenic mechanism(s) are unknown, animal models have been developed to investigate the various disease processes, as well as to enable study of environmental and genetic factors which may contribute to disease development. Numerous parameters can be measured in animal systems, including specific and total immunoglobulin E (IgE), pulmonary eosinophilia, diaphragm contractions and airflow muscle hypertrophy. It is recognized that no single factor is sufficient to lead to a conclusion of occupational asthma, but rather that a selected combination of parameters is most fitting. Animal species selected for study have included: mice, rats, guinea-pigs, rabbits, sheep, horses and nonhuman primates. A guinea-pig system has been utilized for more than 90 yrs and has contributed to the basic understanding of physiological and immunological processes involved in allergic respiratory sensitization. The benefits as well as the disadvantages to be derived from each of the animal systems have been enumerated in this review. Certain caveats must be recognized in using animal systems. Attention must always be given to identifying differences which exist between animal and human systems, including morphological, physiological and immunological factors. The extent of bronchus-associated lymphoid tissue (BALT) differs greatly among animal species and probably plays a major role in development of allergic responsiveness in animals. In using animal systems, it must be appreciated that animals are only surrogates. Results from such studies must be compared with information obtained from clinical evaluation in order to avoid faulty extrapolations. Prudent employment of animal models is expected to advance the recognition, treatment and prevention of occupationally-based asthma.
Biogeographic and ecological regulation of disease: prevalence of Sin Nombre virus in island mice is related to island area, precipitation, and predator richness.

AbstractThe relative roles of top-down and bottom-up forces in affecting disease prevalence in wild hosts is important for understanding disease dynamics and human disease risk. We found that the prevalence of Sin Nombre virus (SNV), the agent of a severe disease in humans (hantavirus pulmonary syndrome), in island deer mice from the eight California Channel Islands was greater with increased precipitation (a measure of productivity), greater island area, and fewer species of rodent predators. In finding a strong signal of the ecological forces affecting SNV prevalence, our work highlights the need for future work to understand the relative importance of average rodent density, population fluctuations, behavior, and specialist predators as they affect SNV prevalence. In addition to illustrating the importance of both bottom-up and top-down limitation of disease prevalence, our results suggest that predator richness may have important bearing on the risk of exposure to animal-borne diseases that affect humans.
The BOLD Plot Thickens: Sign- and Layer-Dependent Hemodynamic Changes with Activation

In this issue of Neuron, Goense et al. (2012) report on high-resolution, layer-specific measurements of BOLD, cerebral blood volume, and cerebral blood flow in regions of positive and negative BOLD associated with a simple visual stimulus. The findings strongly suggest that the hemodynamic mechanisms behind negative signal changes are quite different from those behind positive signal changes.
Heat conduction from a heated particle placed in a two-phase medium with a dispersed phase size comparable to the particle size

The steady rate of heat conduction Q from a heated sphere maintained at a constant temperature different from that of a surrounding two‐phase medium, which consists of an array of spherical particles of thermal conductivity αk and a matrix of conductivity k, is determined by a method of multipole expansion to O(φ4), where φ is the volume fraction of the particles in the array, and by a lubrication analysis for highly conducting and closely packed arrays. The results of the two analyses are combined to obtain estimates of Q that are expected to be accurate over the complete range of α and φ. These results are compared with the predictions of an effective‐medium theory, and it is shown that the predictions of this theory are quite accurate over a rather wide range of α, 0<α<103, for the case of a simple cubic array, even at its maximum allowable volume fraction, but differ by as much as 60% for the case of a face‐centered cubic array.
Designing theory-based systems: a case study

In this paper, we discuss principles for designing and testing computer systems intended to support users' thinking as they perform open-ended or ill-defined tasks. We argue that such systems inherently and inevitably implement a model of users' cognitive behaviors. Making that model explicit can provide system developers with guidance in taking design decisions. However, both model and system must be tested and refined. We discuss these principles in relation to a case study in which our group developed a hypertext-based writing environment and then tested that system in a series of experimental studies of writers' strategies.
Proto‐Gothicism: The Infernal Iconography of Walpole's Castle of Otranto

Summary An analysis of the major supernatural icons or horror symbols of the first Gothic novel, Horace Walpole's Castle of Otranto (1764), suggests that the work's infernal iconography expresses in a fully developed way the central themes of the emergent Gothic tradition: a malign and disorderly cosmos; the impotency of rationalism; supernatural terror and horror as the prevailing conditions of the Gothic universe. The iconography of Gothicism derives from older positive value Systems, codes of religious belief or symbols of social stability, but converts these traditional positive representations of order and security into an iconography of fear, doubt, loss, disintegration of self and disruption of natural law. The primary example of this process of iconographic inversion whereby the negative or darker side of the symbol becomes the dominant object of terror in the Gothic world is the sentient architecture of the haunted Castle of Otranto itself, a former refuge now become a site of terror. Concentrating on the mobile icons of the castle's interior and applying a theory of iconology developed by Theodore Ziolkowski in his Disenchanted Images: A Literary Iconology, the essay explores Walpole's proto-Gothic achievement in preparing the way for the vast eruption of Gothic fiction that would follow in the last decades of the Eighteenth Century.
Information comics: An overview

The analysis of the structure of comics is increasing but only recently have “information comics” been analyzed. These are a subset of comics whose purpose is not to tell a story or entertain but to transfer information or communicate concepts, even though that narrative is often considered an essential element of comics. Information transfer is considered an essential element of many texts, especially educational ones. The effective use of comics in education settings has been discussed since at least 1944. While “information comics” do differ in some aspects, this study will show via Peircean Visual Design that “information comics” are fundamentally the same as other comics, and while comics as a whole may be effective in knowledge transfer there appears to be little data supporting this claim.
Reversal of inhibition of putative dopaminergic neurons of the ventral tegmental area: Interaction of GABAB and D2 receptors

Neurons of the ventral tegmental area (VTA) are critical in the rewarding and reinforcing properties of drugs of abuse. Desensitization of VTA neurons to moderate extracellular concentrations of dopamine (DA) is dependent on protein kinase C (PKC) and intracellular calcium levels. This desensitization is called DA inhibition reversal, as it requires concurrent activation of D2 and D1-like receptors; activation of D2 receptors alone does not result in desensitization. Activation of other G-protein-linked receptors can substitute for D1 activation. Like D2 receptors, GABAB receptors in the VTA are coupled to G-protein-linked potassium channels. In the present study, we examined interactions between a GABAB agonist, baclofen, and dopamine agonists, dopamine and quinpirole, to determine whether there was some interaction in the processes of desensitization of GABAB and D2 responses. Long-duration administration of baclofen alone produced reversal of the baclofen-induced inhibition indicative of desensitization, and this desensitization persisted for at least 60 min after baclofen washout. Desensitization to baclofen was dependent on PKC. Dopamine inhibition was reduced for 30 min after baclofen-induced desensitization and conversely, the magnitude of baclofen inhibition was reduced for 30 min by long-duration application of dopamine, but not quinpirole. These results indicate that D2 and GABAB receptors share some PKC-dependent mechanisms of receptor desensitization.
Relations of Scores on WPPSI and WISC-R at a One-Year Interval:

This study was designed to provide information regarding the relationship between the WPPSI and the WISC-R, over a 1-yr. interval, for a sample of middle-class children of above average intelligenc...
Reducing drinking and related harms in college: evaluation of the "A Matter of Degree" program.

Objectives To examine the effects of a multisite environmental prevention initiative, the “A Matter of Degree” (AMOD) program, on student heavy alcohol consumption and resultant harms at ten colleges. Methods A quasi-experimental longitudinal analysis of alcohol consumption and harms was employed, using repeated cross-sectional survey data from the Harvard School of Public Health College Alcohol Study (CAS). Areas examined included seven measures of alcohol consumption, thirteen measures of alcohol-related harms, and eight measures of secondhand effects of alcohol use by others. Comparisons were conducted on self-reported behavior of students for the ten AMOD sites in aggregate and by level of program implementation, with students at 32 comparison colleges in the CAS, for each outcome. Results No statistically significant change was found in the overall ten-school AMOD program for outcome measures of interest from baseline (1997) to follow-up (2001). However, there was variation in the degree of environmental program development within AMOD during the intervention period. A pattern of statistically significant decreases in alcohol consumption, alcohol-related harms, and secondhand effects was observed, reflecting minor to more substantial changes across measures among students at the five program colleges that most closely implemented the AMOD model of environmental change. No similar pattern was observed for the low implementation sites or at 32 comparison colleges. Conclusions While there was no change in the ten AMOD schools in study measures, significant although small improvements in alcohol consumption and related harms at colleges were observed among students at the five AMOD sites that most closely implemented the environmental model. Fidelity to a program model conceptualized around changing alcohol-related policies, marketing, and promotions may reduce college student alcohol consumption and related harms. Further research is needed over the full course of the AMOD program to identify critical intervention components and elucidate pathways by which effects are realized.
Effects of halothane and methoxyflurane on the hypothalamic-pituitary-adrenal axis in rat

Effects of acute exposure (2 h) to either 1.5% halothane or 0.5% methoxyflurane on chemical mediators of the hypothalamic-pituitary-adrenal (HPA) axis were evaluated in male Sprague-Dawley rats immediately after exposure, after the righting reflex (4 h), or 24 h postexposure. Effects of these anesthetics on hippocampal corticotropin releasing factor (CRF) were also evaluated. Methoxyflurane caused significant elevations in pituitary adrenocorticotropin hormone (ACTH)-like immunoreactivities in all three of the experiment's time groups, yet halothane failed to cause the same response immediately after exposure. Serum ACTH-like immunoreactivities were significantly elevated immediately after exposure to both anesthetics, but were not elevated at 4 and 24 h postexposure. Corticosterone (CORT)-like immunoreactivities were significantly elevated by halothane in all experimental groups, and in the 2- and 24-h groups following methoxyflurane exposure. Hippocampal CRF-like immunoreactivities remained unaffected by either anesthetic. Results indicate that a 2-h exposure to either halothane or methoxyflurane results in significant activation of the rat hypothalamic-pituitary-adrenal axis, and that the activation appears to be sustained over a 24-h period.
Optical Communications With Lasers And Multilayer Elliptical Fibers

Simultaneous two-way communications through a single fiber with solid-state lasers as source are described. A system was designed to use the same optical subsystem for transmitting as for receiving at each of the two communicating stations. A multilayer, single-mode, elliptical fiber capable of preserving the two orthogonally polarized modes of propagation was used as the transmission medium. The multilayer configuration was constructed to confine most of the energy in the fiber core to minimize losses to absorption in the claddings. Separation of the beams was made by a duplexer capable of distinguishing the difference in polarity of the two beams.
Keeping it legal: Refusing rooms to minors and young adults

Abstract Well-thought-out policies can protect hotels from many of the problems typically experienced with young guests while preserving the valuable business generated from this market segment.
Implications of the saltation–abrasion bedrock incision model for steady-state river longitudinal profile relief and concavity

The saltation–abrasion model predicts rates of river incision into bedrock as an explicit function of sediment supply, grain size, boundary shear stress and rock strength. Here we use this experimentally calibrated model to explore the controls on river longitudinal profile concavity and relief for the simple but illustrative case of steady-state topography. Over a wide range of rock uplift rates we find a characteristic downstream trend, in which upstream reaches are close to the threshold of sediment motion with large extents of bedrock exposure in the channel bed, while downstream reaches have higher excess shear stresses and lesser extents of bedrock exposure. Profile concavity is most sensitive to spatial gradients in runoff and the rate of downstream sediment fining. Concavity is also sensitive to the supply rate of coarse sediment, which varies with rock uplift rate and with the fraction of the total sediment load in the bedload size class. Variations in rock strength have little influence on profile concavity. Profile relief is most sensitive to grain size and amount of runoff. Rock uplift rate and rock strength influence relief most strongly for high rates of rock uplift. Analysis of potential covariation of grain size with rock uplift rate and rock strength suggests that the influence of these variables on profile form could occur in large part through their influence on grain size. Similarly, covariation between grain size and the fraction of sediment load in the bedload size class provides another indirect avenue for rock uplift and strength to influence profile form. Copyright © 2008 John Wiley & Sons, Ltd.
Optimization of a pinhole collimator in a SPECT scintillating fiber detector system: A Monte Carlo analysis

Abstract Monte Carlo simulations were used to optimize the dimensions of a lead pinhole collimator in a SPECT system consisting of a line of equally spaced Tc-99m point sources and a plastic scintillating fiber detector. The optimization was performed by evaluating the spatial resolution and scanner sensitivity for each source distribution location and collimator parameter variation. An optimal spatial resolution of 0.43 cm FWHM was observed for a source distribution positioned 2.0 cm from the collimated scintillating fiber detection system with a pinhole radius of 1.0 mm and a collimator thickness of 3.0 cm for a 10,000 emission photon simulation. The optimal sensitivity of 257 cps/MBq (7704 cps/mCi) occurred for a source distance of 2.0 cm, a radius of 3.0 mm and a thickness of 3.0 cm.
A receptor tyrosine kinase specific to hematopoietic stem and progenitor cell-enriched populations

To elucidate the molecular biology of the hematopoietic stem cell, we have begun to isolate genes from murine cell populations enriched in stem cell activity. One such cDNA encodes a novel receptor tyrosine kinase, designated fetal liver kinase-2 or flk-2, which is related to the W locus gene product c-kit. Expression analyses suggest an extremely restricted distribution of flk-2. It is expressed in populations enriched for stem cells and primitive uncommitted progenitors, and is absent in populations containing more mature cells. Therefore, this receptor may be a key signal transducing component in the totipotent hematopoietic stem cell and its immediate self-renewing progeny.
Glutathione as a depigmenting agent : an overview

Glutathione is an ubiquitous compound found in our bodies. Aside from its many ascribed biologic functions, it has also been implicated in skin lightening. We review in vitro and in vivo studies that show evidence of its involvement in the melanogenic pathway and shed light on the its anti-melanogenic effect. Proposed mechanisms of action include: (a) direct inactivation of the enzyme tyrosinase by binding with the copper-containing active site of the enzyme; (b) mediating the switch mechanism from eumelanin to phaeomelanin production; (c) quenching of free radicals and peroxides that contribute to tyrosinase activation and melanin formation; and d) modulation of depigmenting abilities of melanocytotoxic agents. These concepts supported by the various experimental evidence presented form basis for future research in the use of glutathione in the treatment of pigmentary disorders.
Initial bandwidth resulting from splitless and solid phase microextraction gas chromatographic injections

The initial width of the injected solute bands is a major determinant of the final measured peak width. While the individual processes contributing to this intial width have been observed and described qualitatively by many authors, little attention has been focused on their quantitative relationship. Using solid phase microextraction (SPME) and splitless injections of a hydrocarbon test mixutre the contributions to overall peak variance in SPME and splitless injections can be separated and quantitated. In SPME, it is seen that thermal focusing or rapid desorption must serve to provide focused bands. In splitless, thermal fucusing and solvent effects provide focusing. Variance contributions for each of these are calculated and shown.
Simple and effective modification of a sagittally focusing x-ray diffraction optic

Some experiments performed at bending magnet beamlines at the Advanced Photon Source (APS) will benefit from a focused photon beam. A commercial sagittal focusing bender that uses a simple rectangular plate as the diffraction element could be utilized for this purpose. However, the thin rectangular diffracting plate, specified by the manufacturer, is susceptible to anticlastic bending. A simple ribbed plate that utilizes this commercial bender but that reduces anticlastic bending is proposed as a solution. This design uses a pair of sufficiently stiff ribs on the diffracting surface, which substantially suppresses anticlastic bending. The finite element analysis (FEA) method was used to predict the overall structural response of this sagittally bent plate and its anticlastic distortion. Results are compared with unribbed plates showing an effective reduction in anticlastic bending.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Loma Prieta damage largely attributed to enhanced ground shaking

Earthquake hazards are commonly treated independently by Earth scientists, yet when a large earthquake occurs, property losses are seldom totaled separately for each earthquake hazard. Four years after the 1989 Loma Prieta earthquake rolled through northern California, a quantitative answer to the following question is not yet available: How much damage was caused by ground shaking, liquefaction, landslides, tectonic ground rupture, or tsunami? Although the consequences of one earthquake do not necessarily follow for others, an answer to this question will help guide public policy and set research priorities. The cost effectiveness of earthquake hazard mitigation can be improved when the relative significance of earthquake hazards is known because it enables public agencies to concentrate mitigation efforts on the most portentous hazards.
Evaluating Individual Differences in Psychological Processes

Better understanding individual differences in social, cognitive, and behavioral processes is a core goal of much psychological theory and research. Although great progress has been made toward this goal, I argue here that the classical design and analysis approach that dominates individual difference research, namely, the collection of single-time-point data and application of standard linear regression models, potentially limits further advances. In particular, the opportunity to evaluate individual differences in psychological processes is restricted by the estimation of a single effect to represent the relationship between variables. I discuss alternative analysis and design options that offer the opportunity to more fully examine individual differences in psychological processes.