cssi/SciSciGPT-SciSciNet huggingface dataset:
Tyrosyl Phosphorylated PAK1 Regulates Breast Cancer Cell Motility in Response to Prolactin through Filamin A

The p21-activated serine-threonine kinase (PAK1) is activated by small GTPase-dependent and -independent mechanisms and regulates cell motility. Both PAK1 and the hormone prolactin (PRL) have been implicated in breast cancer by numerous studies. We have previously shown that the PRL-activated tyrosine kinase JAK2 (Janus tyrosine kinase 2) phosphorylates PAK1 in vivo and identified tyrosines (Tyr) 153, 201, and 285 in the PAK1 molecule as sites of JAK2 tyrosyl phosphorylation. Here, we have used human breast cancer T47D cells stably overexpressing PAK1 wild type or PAK1 Y3F mutant in which Tyr(s) 153, 201, and 285 were mutated to phenylalanines to demonstrate that phosphorylation of these three tyrosines are required for maximal PRL-dependent ruffling. In addition, phosphorylation of these three tyrosines is required for increased migration of T47D cells in response to PRL as assessed by two independent motility assays. Finally, we show that PAK1 phosphorylates serine (Ser) 2152 of the actin-binding protein filamin A to a greater extent when PAK1 is tyrosyl phosphorylated by JAK2. Down-regulation of PAK1 or filamin A abolishes the effect of PRL on cell migration. Thus, our data presented here bring some insight into the mechanism of PRL-stimulated motility of breast cancer cells.
Inotropic, chronotropic, and radioligand binding characteristics of leukotriene B4 in cardiac myocyte, papillary muscle, and membrane preparations.

Abstract Cardioprotective effects of dietary fish oil consumption have been attributed to the substitution of eicosapentaenoic acid (EPA) for arachidonic acid (AA) in cellular membranes. This substitution blocks the formation of leukotriene B 4 (LTB 4 ) which is elaborated locally in the area of ischemic myocardium. We studied the in vitro inotropic, chronotropic, and radioligand binding characteristics of LTB 4 to gain potentially important insights into the mechanisms involved in the cardioprotective effect of EPA. LTB 4 was a concentration-dependent and reversible negative inotrope in isolated papillary muscle preparations. LTB 4 significantly blocked the positive inotropic effect of Bay K 8644 (BK) (calcium channel regulator) on papillary muscles and the positive chronotropic effect of BK on spontaneously beating neonatal cardiac myocytes. LTB 4 had no direct effect on [ 3 H]PN200-110 binding to cardiac sarcolemmal L-type calcium channels or [ 3 H]ryanodine binding to cardiac SR calcium release channels. These studies support a potentially important indirect effect of LTB 4 on myocardial E-C coupling.
Examination of differences between successful and unsuccessful elderly hearing aid candidates matched for age, hearing loss and gender.

This study examined group differences on a variety of measures for three groups of elderly hearing aid candidates matched for gender, age and hearing loss. These three groups were: (1) 26 candidates who declined amplification (non-adherents): (2) 24 individuals who purchased hearing aids, but subsequently returned them (rejected HA); and (3) 26 who purchased hearing aids and continued to use their hearing aids for at least the first 6 months following delivery (accepted HA). Following demonstration of adequate reliability for these measures, using the non-adherents as the test-retest study sample, group differences were examined for each pre-fit measure. The group of non-adherents who declined amplification differed from the two groups who purchased hearing aids on their scores for the Hearing Handicap Inventory for the Elderly (HHIE) and for several scales of the Communication Profile for the Hearing Impaired (CPHI) that assessed the individual's personal adjustment to hearing impairment. These findings ...
Comparison of Nidek 3Dx and Donaldson Simultaneous Stereoscopic Disk Photography

We performed a retrospective study on 100 eyes of 55 consecutive patients to compare the stereoscopic quality of simultaneous stereoscopic disk photographs and the reproducibility of optic nerve assessments using the Nidek 3Dx system and the Donaldson fundus camera. Photographs were taken on the same eyes on the same dates and reviewed independently by one clinician three times in a randomized, masked fashion. Mean cup/disk ratios using the Nidek 3Dx system were similar to mean cup/disk ratios using the Donaldson camera. There was significantly less variability of disk analysis using the Nidek 3Dx system than the Donaldson camera (F = 1.6, P = .01, df = 99). Overall mean stereoscopic quality was significantly better with the Nidek system (3.2 ± 1.15 S.D.) than with the Donaldson camera (2.5 ± 1.27 S.D., P
A coloring invariant for ribbon L-tetrominos

Abstract We investigate tiling problems for regions in a square lattice by ribbon L -shaped tetrominoes. Our results show that tiling of the first quadrant by ribbon L -tetrominoes is possible only if it reduces to a tiling by 2×4 and 4×2 rectangles. A consequence is the description of all rectangles that can be tiled by ribbon L -shaped tetrominoes.
Demonstrating morphine's potentiating effects on sucrose-intake

Mildly deprived rats (18-hr of deprivation of water) were given the opportunity to take a solution of sucrose daily for periods of either 10, 18, 31, 56, or 100 min. After daily intakes stabilized and prior to a session, rats were given an injection of either morphine sulfate, 1.0 mg/kg, or naloxone hydrochloride, 2.5 mg/kg, an agonist and an antagonist, respectively, at the opioid receptors. Naloxone, as expected, decreased intakes regardless of the test-session's length. Morphine decreased intakes of the shorter sessions, but increased intake of the longest session. Subsequently, injections of morphine were given 56 min into a 100-min session. These injections also increased intake. Morphine's effects in potentiating intake seem to have special relevance with respect to the continuance of ingestion. Variations across experiments, in duration of test-sessions, could account for the variations in conclusions drawn about whether or not morphine and other agonists potentiate intake of ingesta.
Rational expectations and M2 demand

This essay expands on existing studies of M2 money demand. It differs in that it applies a rational expectations approach to an adaptive expectation model. Unlike the adaptive expectations models, the author includes an explanatory variable for expectations of future inflation. The expectation variables used are: the actual inflation rate (t + 1) and the Livingston Survey from the Philadelphia Fed. By using the different measures of expectations the author is able to compare several adaptive expectations models that appear in the literature and the rational expectations models for fit and forecast ability. The empirical results are such that the importance of including the rational expectations variable is evident even though the overall fit of the equation is comparable to one of the existing adaptive expectations models.
Furthering the study of real-time life extending control for ocean energy conversion

Renewable energy is a topic of significant interest and importance in the world today. Ocean wave energy, particularly on the western coasts of land masses, has considerable potential as a renewable resource. However, to rightly evaluate the overall cost of energy for wave energy converters, survivability and maintenance issues must be addressed. This study endeavors to develop tools for real-time damage quantification for use with life extending control algorithms, and shows that energetic sea conditions may cause much greater damage than the associated benefits in power production. Therefore, control strategies that consider a tradeoff between damage and power production will be necessary in implementing cost effective wave energy converter operation.
An ultrastructural study of the papillary layer and its vascular bed in the kitten enamel organ.

Ultrastructure and three-dimensional architecture of the papillary layer and associated capillaries in the enamel organ of 2–3-month-old kittens were examined by means of routine thin sections, freeze-fracture, and scanning electron microscopy of the tissues digested by HCl-collagenase and of vascular corrosion casts. Outwardly, the papillary layer formed gently sloping upheavals, but did not show prominent papillary ridges. The papillary cells were characterized by a high concentration of intramembranous particles on the plasma membrane P-face, by numerous hemi-annular gap junctions between the cell process of one papillary cell and the cell body of another host cell, and by annular gap junctional vesicles in the subsurface cytoplasm. Some annular gap junctions appeared partially degenerated. These findings led us to speculate that these annular gap junctions are produced by the endocytosis of gap junctional membranes from the cell surface into the subsurface cytoplasm. Capillaries were distributed on the enamel organ within shallow furrows between the papillary upheavals. A part of these capillaries penetrated deeply into the enamel organ but did not contact the ameloblasts. The endothelial walls of the capillaries were pierced with many endothelial fenestrations, especially when facing the papillary layer. The endothelial cell also contained numerous micropinocytotic vesicles throughout its entire cytoplasm. These findings suggest that the papillary cells and associated capillaries are highly specialized for transport of solutes and molecules between the vascular region and the enamel organ during the phase of enamel maturation.
How should we release vitreomacular traction: surgically, pharmacologically, or pneumatically?

O VER THE PAST 2 DECADES, THANKS IN PART TO the development of optical coherence tomography, clinicians have gained increasing understanding of the critical role played by the vitreous in macular and retinal vascular disease. Age-related posterior vitreous detachment (PVD), once thought to be an acute event with precipitous onset and rapid progression, is now known to progress slowly over many months or years before its culmination at the time of vitreopapillary separation. In most individuals, the early stages of PVD are physiologic—uncomplicated and asymptomatic until vitreous separation from the optic disc margin produces symptoms and signs of a Weiss ring. However, in a minority of patients, early-stage PVD is pathologic and may cause a variety of macular complications. These complications result from the tractional effects of perifoveal PVD with vitreomacular adhesion, from the process of vitreoschisis, in which cortical vitreous remnants on the retinal surface after vitreous detachment become scaffolds for fibrocellular proliferation, or both. It is now apparent that a significant number of the disorders commonly treated by vitreoretinal specialists are caused or exacerbated by these 2 pathologic mechanisms associated with early-stage PVD. Fibrocellular organization of vitreous remnants left on the retinal surface during vitreoretinal separation is considered by most authorities to be the likely cause of idiopathic epiretinal membrane. Idiopathic lamellar and fullthickness macular hole, tractional cystoid macular edema, and the vitreomacular traction syndrome are caused directly by the tractional effects of early-stage (perifoveal) PVDwith vitreomacular adhesion. Other conditions, such as myopic traction maculopathy, diabetic macular edema, and possibly neovascular AMD, are not caused primarily, but may be exacerbated, by pathologic features of PVD. Partial PVD also plays an important pathogenic role in proliferative retinopathies and in the vitreopapillary traction syndrome.
Characterization of a uranium-rich organic material obtained from a South Texas lignite

Abstract Results of the density gradient fractionation of a uranium-rich (≈2500 ppm) lignite indicate that the element may be associated with the organic matter in the coal. Dimethyl sulphoxide (DMSO) extracts 40–50% of the uranium from the lignite. Addition of several solvents such as benzene, water and acetone to the DMSO extract yields precipitates which are highly enriched with uranium. Elemental and functional group analyses and infrared absorption chracteristics of the precipitates indicate that they closely resemble coal humic acids. A wavelength-dispersive X-ray dot map of the benzene-derived precipitate shows a homogeneous distribution of uranium. Mass spectrometric information shows that the most abundant species in the precipitates have molecular weights
Transonic stability and control of aircraft using CFD methods

Implementation of a capability to calculate longitudinal short-period response in the CAP-TSD (Computational Aeroelasticity Program - Transonic Small Disturbance) finite-difference code is described. The code, developed recently at the NASA Langley Research Center, is capable of solving steady and unsteady flows about complete aircraft configurations and is used primarily for aeroelastic calculations in the critical transonic speed range. The longitudinal short-period equations of motion in state-space form have been coupled to the time-accurate lift and moment calculated by the program. Transient responses to an elevator pulse for free-flying aircraft demonstrate the new capability. A trim routine is also added to the code to obtain trim automatically during steady-state flow field convergence. Stability and control derivatives are estimated from the calculated transient response by a maximum likelihood estimation program. Results for a fighter configuration and a general aviation configuration are presented to assess the capability.
Post-depositional Structures in the Lias, South Wales

ABSTRACT References to bedding surface irregularities in the British Lias limestones as being of secondary origin are reviewed in light of recent studies in South Wales. Protuberances on both top and bottom of some limestone units are the products of loading, vertical stresses created by weight of overburden after burial, and interstratal sliding partly due to local subsidence; some structures are further. distorted by localized, multi-directional, compactional stresses. Four descriptive limestone groups have been identified and post depositional processes contributing to their formation analyzed. Many of the structures described from the Lias of Britain occur in similar Paleozoic sediments of North America, and have yet to be described.
The socio‐emotional effects of non‐maternal childcare on children in the USA: a critical review of recent studies

This paper provides a review of studies published between 1998 and 2006 that have evaluated the relationship between non‐maternal childcare and children’s social‐behavioral adjustment. Recent studies have focused on how the factors of non‐maternal childcare quantity, quality, type and timing interact with factors of family background and child characteristics to affect various indicators of social‐behavioral adjustment. Findings indicate that average weekly hours of non‐maternal childcare is the strongest and most consistent childcare predictor of social‐behavioral outcomes. Entry into childcare during the first year and extensive non‐maternal childcare throughout early childhood predicts less social competence and cooperation, more problem behaviors, negative mood, aggression and conflict. When family background factors are also considered, maternal sensitivity is the most consistent predictor of social‐behavioral adjustment. New theoretical frameworks and methodologies are needed to explore the mechanis...
Double ionization of CO2 by photon impact

Double ionization of CO2 by photon impact from the double-ionization threshold at energies of 36.2 eV (342 A) to 110 eV (113 A) has been observed. The ratio of doubly to singly charged ions shows a linear rise with photon energy for approximately 15 eV above the threshold and reaches a constant value of about 2% between 67 and 110 eV.
Healthcare information portal: a web technology for the healthcare community

Abstract Telemedicine technology already provides tremendous social benefits. A comprehensive, Web-based healthcare information portal would be a major further advancement. This article discusses the need for developing such a portal, proposes a framework, and analyses its benefits and challenges.
RUNX1-RUNX1 homodimerization modulates RUNX1 activity and function

RUNX1 (AML1, CBFalpha2, PEBP2alphaB) is a transcription factor essential for the establishment of the hematopoietic stem cell. It is generally thought that RUNX1 exists as a monomer that regulates hematopoietic differentiation by interacting with tissue-specific factors and its DNA consensus through its N terminus. RUNX1 is frequently altered in human leukemia by gene fusions or point mutations. In general, these alterations do not affect the N terminus of the protein, and it is unclear how they consistently lead to hematopoietic transformation and leukemia. Here we report that RUNX1 homodimerizes through a mechanism involving C terminus-C terminus interaction. This RUNX1-RUNX1 interaction regulates the activity of the protein in reporter gene assays and modulates its ability to induce hematopoietic differentiation of hematopoietic cell lines. The promoters of genes regulated by RUNX1 often contain multiple RUNX1 binding sites. This arrangement suggests that RUNX1 could homodimerize to bring and hold together distant chromatin sites and factors and that if the dimerization region is removed by gene fusions or is altered by point mutations, as observed in leukemia, the ability of RUNX1 to regulate differentiation could be impaired.
A controlled study of dawn simulation in subsyndromal winter depression

In a randomized, cross-over design, 16 subjects with recurrent autumn-winter symptoms but without major depression were treated with 4 days of dawn simulation consisting of a gradually increasing illuminance over 45 min peaking at 100 lx (slow dawn) and with 4 days of a light rapidly increasing over a 4 s period to 100 lx (rapid dawn). The slow dawn was significantly better than both baseline and the rapid dawn in improving subjective measures of energy, mood, social interest, productivity, quality of sleep and quality of awakening.
Absence ofp15INK4Bandp16INK4AGene Alterations in Primary Cervical Carcinoma Tissues and Cell Lines with Human Papillomavirus Infection

Abstract Objective. Alterations of the p15 INK4B and p16 INK4A gene which are separated by 25 kb on chromosome 9p21 have been reported in various tumor-derived cell lines and primary tumors, but the role of these genes in cervical cancer is unknown. To determine the frequency of deletions and point mutations of these genes in human cervical cancer, we examined for alterations of the p15 INK4B and p16 INK4A genes in cervical carcinomas. Methods. We examined 57 primary tumors and matched normal tissues and 3 cervical cancer-derived cell lines. All the tumor tissues and cell lines were human papillomavirus (HPV) positive. Deletions or point mutations of exon 2 of the p INK4B gene and exons 1, 2, and 3 of the p16 INK3A gene were examined by polymerase chain reaction and direct sequencing, respectively. Results. Our data indicate no evidence for intragenic homozygous deletion or point mutation in the primary cervical cancer tissues or cancer-derived cell lines. Conclusion. Deletions or point mutations in the p15 INK4B or p16 INK4A gene may not be required for the development of HPV-positive cervical cancer or for establishment of cervical cancer cell lines.
Focal Epithelial Hyperplasia: Heck Disease

Two sisters of Mexican ancestry had focal epithelial hyperplasia (FEH). The lesions on the oral mucosa of the older child were initially misinterpreted as representing sexual abuse. Microscopic evaluation of a hematoxylin and eosin-stained section from a lower lip papule demonstrated the histologic features of FEH. Although human papillomavirus (HPV) type 13 and HPV32 have been most consistently present in FEH lesions, types 6, 11, 13, and 32 were not detected in the paraffin-embedded tissue specimen of our patient using an in situ hybridization technique. The lesions persisted or recurred during management using destructive modalities; subsequently, they completely resolved spontaneously.
Calpain 2 and PTP1B function in a novel pathway with Src to regulate invadopodia dynamics and breast cancer cell invasion

Invasive cancer cells form dynamic adhesive structures associated with matrix degradation called invadopodia. Calpain 2 is a calcium-dependent intracellular protease that regulates adhesion turnover and disassembly through the targeting of specific substrates such as talin. Here, we describe a novel function for calpain 2 in the formation of invadopodia and in the invasive abilities of breast cancer cells through the modulation of endogenous c-Src activity. Calpain-deficient breast cancer cells show impaired invadopodia formation that is rescued by expression of a truncated fragment of protein tyrosine phosphatase 1B (PTP1B) corresponding to the calpain proteolytic fragment, which indicates that calpain modulates invadopodia through PTP1B. Moreover, PTP1B activity is required for efficient invadopodia formation and breast cancer invasion, which suggests that PTP1B may modulate breast cancer progression through its effects on invadopodia. Collectively, our experiments implicate a novel signaling pathway involving calpain 2, PTP1B, and Src in the regulation of invadopodia and breast cancer invasion.
Molecular biology: DNA replication reconstructed.

Chromosomes must be faithfully duplicated in each cell-division cycle to ensure genome integrity. The in vitro reconstitution of DNA-replication initiation in yeast allows mechanistic studies of this fundamental process. See Article p.431
Determination of inorganic cations in fermentation and cell culture media using cation-exchange liquid chromatography and conductivity detection

Reliable methods to quantitate inorganic cations in biological culture media are often helpful for medium optimization and comprehensive process monitoring and control. Analysis of inorganic cations found in culture media was accomplished by ion chromatography for several types of microbial fermentations as well as mammalian and insect cell culture samples. An isocratic method consisting of a Dionex IonPac CS12 analytical column and 4 mM methanesulfonic acid mobile phase was used with suppressed conductivity detection. Sample preparation was a simple dilution of filtered broth with water. The analyses time was 20 min. This analysis accurately monitored eight inorganic cations, several of which are commonly present in fermentation media (Na+, NH4+, K+, Mg2+, Ca2+).
A study of the reactive properties of the chlorinated ethylenes

The chlorinated ethylenes are a group of six molecules having the basic ethylene structure, but differing in the numbers and locations of chlorine substituents. The primary aim of this work has been to determine how the progressive substitution of chlorines affects the reactive properties of the molecules, especially toward electrophilic attack. This is of particular interest because the chlorinated ethylenes, which are widely distributed in the environment, are known to have various adverse biological effects, including (for some of them) carcinogenicity. There is considerable evidence that the first step in the metabolism of these molecules is epoxidation of the double bond, a process which is believed to involve interaction with an electrophilic oxygen species. Accordingly the electrostatic potential that is produced in the space around each molecule by its nuclei and electrons has been computed. This potential is known to be an effective means for studying electrophilic processes; the initial tendency of an approaching electrophile is to go to those regions of the molecule where the electrostatic potential is most negative. The overall trend found in this work is a very distinct decrease in the sizes and magnitudes of the regions of negative potential as the number of chlorines increases. This holds true for the π-bond regions, and it is also true for the regions around the chlorines themselves. (cis- 1,2-Dichloroethylene is an interesting exception to this trend.) Thus the chlorinated ethylenes are expected to show a general decrease in reactivity toward electrophiles as the number of chlorines increases, as is indeed found experimentally. It is suggested that the marked weakening of the negative chlorine potentials that occurs as the number of chlorines increases may be attributed to the limited capacity of the double bond region to provide electronic charge for inductive withdrawal.
Spatial network modeling for databases

Spatial networks like transportation, power, and pipeline networks are a ubiquitous spatial concept in everyday life and play an important role for navigational and routing purposes. Database support for large spatial networks in order to represent, store, query, and manipulate them is rare. Our paper aims to provide the beginning of a conceptual, abstract, and formal model of spatial networks, called Spatial Network Algebra (SNA), that includes types and operations and is supposed to serve as a specification for their later implementation in spatial database systems and GIS. Finally, we show how our spatial network concepts can be embedded into an SQL-like query language.
Avoidance Responses of Rainbow Trout andUtah Chub to Rotenone

Abstract Avoidance response to the piscicide rotenone was evaluated in rainbow trout Oncorhynchus mykiss and Utah chub Gila atraria. Each fish species was exposed to 12 separate test formulations that varied in the amount of rotenone present as well as the form of rotenone. Test formulations that contained no rotenone were water, liquid carrier, and inert powder. Formulations that contained rotenone (liquid rotenone, powdered rotenone, and a rotenone-only mixture) were tested at three different concentrations (0.045, 0.075, and 0.15 mg rotenone/L). Only rainbow trout exhibited an avoidance response in this study to the liquid and powdered formulations of rotenone. Presence of the carrier, piperonyl butoxide, in the liquid formulation may be a factor in rainbow trout avoidance of liquid rotenone, since trout avoided the liquid carrier treatment too.
A Note on Bar-Gera's Algorithm for the Origin-Based Traffic Assignment Problem

Recently, Bar-Gera (Bar-Gera, H. 2002. Origin-based algorithm for the traffic assignment problem. Transportation Sci.36(4) 398--417) proposed a quasi-Newton method for the origin-based formulation of the user equilibrium traffic assignment problem. This note shows that Bar-Gera's algorithm may generate negative second-order derivative, leading to a “wrong search direction,” which compromises the overall convergence performance. We prove that this shortcoming can be overcome by approximating the second-order derivative with an upper bound. The revised algorithm not only fixes a theoretical flaw but indeed demonstrates more satisfying computational performance in numerical experiments. This note also offers a rigorous derivation of optimality conditions that synthesizes the results of the literature.
Synaptic dynamism measured over minutes to months: age-dependent decline in an autonomic ganglion

Naturally occurring rearrangements of synaptic terminals are common in the nervous systems of young mammals, but little is known about their incidence in adults. Using transgenic mice that express yellow fluorescent protein (YFP) in axons, we repeatedly imaged nerve terminals in the parasympathetic submandibular ganglion. We found that the pattern of synaptic branches underwent significant rearrangements over several weeks in young adult mice. In older mice, rearrangements were less common, and synaptic patterns on individual neurons were recognizable for many months to years. Axonal branches frequently retracted or extended on a time scale of minutes in young adult mice, but seldom in mature animals. These results provide direct evidence for a decrease in plasticity of interneuronal connections as animals make the transition from young adulthood to middle age. The long-term stability of synaptic patterns could provide a structural basis for the persistence of memory in the adult nervous system.
Chronic guanethidine treatment increases cardiac beta-adrenergic receptors.

VARIOUS pharmacologically active agonists capable of altering cell function have been shown to interact primarily with specific receptors on the outer cell membrane1. Evidence has accumulated from several systems to suggest that there may be a dynamic and inverse relationship between the number or density of receptors on the membrane surface and the degree of receptor occupancy by agonist2,3. We present here experiments which demonstrate in rat hearts that chronic withdrawal of adrenergic stimulation produced by guanethidine treatment in vivo results in increased cardiac β-adrenergic receptor density. Further, in isolated, perfused hearts obtained from guanethidine-treated animals, there is an increased cyclic AMP (cAMP) accumulation in response to the β-adrenergic agonist isoprenaline, suggesting that the increased numbers of receptors may be related to the increased biochemical response.
Multiphoton Ionization Spectroscopy of High-Lying, Even-Parity States in Calcium

Strong ionization signals have been observed in Ca following two-photon absorption to the bound, even-parity $J=0$ and $J=2$ states. Using known Ca absorption lines for calibration, 72 new states have been classified, and their energies have been determined to \ifmmode\pm\else\textpm\fi{} 0.1 ${\mathrm{cm}}^{\ensuremath{-}1}$. The new $J=0$ states have a constant quantum defect, whereas the $J=2$ states do not.
Hybrid Gold/Silica/Nanocrystal-Quantum-Dot Superstructures: Synthesis and Analysis of Semiconductor−Metal Interactions

We report on the synthesis and spectroscopic characterization of well-defined hybrid structures that consist of a gold core overcoated with a silica shell, followed by a dense monolayer of CdSe nanocrystal quantum dots (QDs). The dielectric silica spacer of a controlled thickness provides a simple means for tuning interactions between the QD emitters and the metal core. To illustrate this tunability, we demonstrate switching between QD emission quenching and enhancement by varying the silica shell thickness. Synthetic procedures developed here employ a final step of self-assembly of QDs onto the silica shell performed via simple titration of the QD solution with prefabricated core/shell Au/SiO2 particles. This approach allows us to perform an accurate quantitative analysis of the effect of the metal on the QD emission intensity. One important result of this analysis is that nonuniformity of nonradiative rates across the QD ensemble has a significant effect on both the magnitude and the shell-thickness dep...
A resistometric study of hydride precipitation in Alpha Titanium

Abstract In this work a resistometric technique has been used to investigate the effect of temperature and structure on the kinetics of hydride precipitation in alpha-titanium containing less than 0.5 at. % hydrogen for the temperature range −100°C to + 100°C. For annealed material it is found that the precipitation reaction occurs most readily at approximately room temperature, whereas at higher temperatures there appears to be a severe nucleation problem. The effect of deformation is to minimize this nucleation problem and to increase the reaction rate at all temperatures. It is concluded that nucleation is principally heterogeneous and that the deformation process affects the precipitation kinetics through a combination of factors related to the number, type and distribution of these nucleation sites.
Diffusion and capillary flow in track-etched membranes

Abstract Nitrogen transport at 77 K through the cylindrical pores in 0.01 μm track-etched membranes occurs by a combination of Knudsen diffusion and capillary flow. This transport can be quantitatively predicted without adjustable parameters from a modified form of the theory of Abeles et al. (1991). This implies that some anomalies previously observed for transport with capillary condensation are geometrical artifacts of the heterogeneous pores which were used.
Structure and Stability of Multielectron Bubbles in Liquid Helium

The charge-density distribution in multielectron bubbles is calculated with use of a generalized Thomas-Fermi method. The exchange and correlation effects are found crucial; these result in a density profile much narrower than that obtained by simple estimates. The observed stability of the bubbles is explained in terms of the nonlinear coupling between the radial and angular modes of oscillation. Above a threshold oscillation amplitude a period-doubling instability sets in.
Conductive Education and the National Curriculum: an integrated approach

This article is a single case study of a community special school that integrates the principles and practice of Conductive Education into its curriculum. The article covers this process over a period of ten years. For five of these Jill Wilson was head teacher of the school and she traces the developments at the school over this period, starting from the point when staff first went to the Peto Institute in Budapest for training. She goes on to examine the ways in which the school has placed Conductive Education at the centre of its philosophy. In addition it traces the development of the curriculum, which encompasses the National Curriculum, along with the school's developmental, experiential and personal social and health education curricula. The net result is a full and appropriate curriculum for the pupils at the school built on and around the philosophy and practice of Conductive Education.
Rigorous Bounds for Time-Dependent Correlation Functions

Rigorous upper and lower bounds are determined for time-dependent correlation functions, of the type used in statistical mechanics and spectroscopy. The input data are the values of any finite number of initial time derivatives of the correlation function. As an example, bounds are found for the classical velocity correlation function for a lattice vibration problem. The bounds are found to be much more accurate than the Taylor series based on the same time derivatives.
Cyclopentadienyl—Actinide Complexes: Bonding and Electronic Structure

Shortly after the discovery of ferrocene, Reynolds and Wilkinson demonstrated that actinide elements are capable of forming organometallic compounds containing the cyclopentadienyl (Cp) ligand. The compound they reported, [Cp3UCl], was the first of a host of organoactinide complexes that contain Cp and substituted Cp ligands. In 1968, Streitwieser and Muller-Westerhoff synthesized uranocene, [(C8H8)2U], a molecule whose existence had been predicted five years earlier by R. D. Fischer. Because uranocene has no analogue in transition-metal chemistry, its synthesis stimulated new interest in organoactinide chemistry and in comparisons with organotransition-metal chemistry. Since that time, Cp and substituted Cp ligands, such as pentamethylcyclopentadienyl (Cp*), have become the most important and flexible ligands in actinide organometallic chemistry. In the past 15 years especially, the bonding of Cp ligands to actinide elements has been extensively probed by both experiment and theory. There are both significant similarities and equally significant differences in the bonding of the Cp ligand to the f-element metals compared to the d-element metals.
Predisposition for burnout among first‐year teachers

(1988). Predisposition for burnout among first‐year teachers. The Teacher Educator: Vol. 24, No. 2, pp. 13-21.
Synthesis and Characterization of the First Potent Inhibitor of Yapsin 1 IMPLICATIONS FOR THE STUDY OF YAPSIN-LIKE ENZYMES

Abstract The potent peptidic inhibitor, Y1, of the basic residue-specific yeast aspartyl protease, yapsin 1, was synthesized and characterized. The inhibitor was based on the peptide sequence of a cholecystokinin13–33 analog that yapsin 1 cleaved with an efficiency of 5.2 × 105 m −1 s−1 (Olsen, V., Guruprasad, K., Cawley, N. X., Chen, H. C., Blundell, T. L., and Loh, Y. P. (1998) Biochemistry 37, 2768–2777). The apparent K i of Y1 for the inhibition of yapsin 1 was determined to be 64.5 nm, and the mechanism is competitive. Y2 was also developed as an analog of Y1 for coupling to agarose beads. The resulting inhibitor-coupled agarose beads were successfully used to purify yapsin 1 to apparent homogeneity from conditioned medium of a yeast expression system. Utilization of this new reagent greatly facilitates the purification of yapsin 1 and should also enable the identification of new yapsin-like enzymes from mammalian and nonmammalian sources. In this regard, Y1 also efficiently inhibited Sap9p, a secreted aspartyl protease from the human pathogen,Candida albicans, which has specificity for basic residues similar to yapsin 1 and might provide the basis for the prevention or control of its virulence. A single-step purification of Sap9p from conditioned medium was also accomplished with the inhibitor column. N-terminal amino acid sequence analysis yielded two sequences indicating that Sap9p is composed of two subunits, designated here as α and β, similar to yapsin 1.
Envelope stability of a thermistor controlled oscillator

Abstract An analysis of the envelope stability and transient response of a thermistor-controlled oscillator is presented. The particular circuit considered is the Meacham Bridge Oscillator with an indirectly heated thermistor. The equations describing the performance of the Meacham Bridge Oscillator with an indirectly heated thermistor are derived. These system equations are simultaneous nonlinear integro-differential equations. Since an analytical solution for these equations is impossible to obtain, simplified envelope equations which are still simultaneous nonlinear differential equations are derived from the system equations. Singular point and phase-plane analyses of the simplified envelope equations are followed by a numerical analysis of the original system equations. An experimental circuit is built and studied for transient responses. The analytical solution for the simplified envelope equations are compared with the numerical solution of the original system equations and the experimental results.
Freezing of Dynamics of a Methyl Group in a Protein Hydrophobic Core at Cryogenic Temperatures by Deuteron NMR Spectroscopy

Proteins undergo a number of changes when their temperature is dropped from the physiological range to much lower values. One of the most well-known dynamical changes undergone by proteins in a solid state is a so-called protein glass-transition, which is a dynamic transition occurring at about 200-230K leading to a loss of biological activity.1,2 X-ray diffraction, neutron scattering studies, and dielectric spectroscopy, as well as evidence from NMR relaxation measurements, indicate freezing of slow collective modes of motion below the glass transition temperature.3-8 Various arguments have been presented that connect the transition to solvent participation.1,4,8-10 In addition to the solvent-related modes that are frozen below the glass-transition temperature, there are anharmonic motions at temperatures below 200K which are likely to be dominated by methyl group dynamics down to about 100K.2,5,7 Recent neutron-scattering and NMR studies emphasize the role of these modes in low temperature dynamics. 2,5,7,11,12 One of the latest works on the subject by Bajaj et al.11 has reported a structural transition associated with dynamic processes in a solvent-free polypeptide. Thus, protein dynamics at low temperatures are complex and more studies are required to discern their pattern.
FRACTIONATION STUDY OF THE RESIDUAL OVARY

THE RECOGNITION, many years ago, of the ovary as an organ of internal secretion has been followed by numerous preparations of extracts from ovarian tissue. These extracts when administered to female animals were expected to introduce characteristic changes in accessory sex organs. The greatest obstacle encountered in the earlier work was the lack of a rapid, quantitative method of assay. Observations made by Stockard and Papanicolaou (i) of the changes in the epithelium of the vagina, and the hypertrophy of the uterus have led to such a rapid quantitative method of assay. Long and Evans (2), Coward and Burn (3), D'Amour and Gustavson (4), and many others were helpful in refining and adapting the vaginal smear method as a rapid, quantitative method of assay of extracts containing estrogenic compounds. In the study of the ovary, most of the work has been done on the follicular fluid, on the whole ovarian extracts, and on the residual ovary. In table 1 below are listed some of the workers in the field, toget...
Detection of novel RNA viruses: morbilliviruses as a model system

Recent advances in molecular detection of viral-specific nucleic acid sequences have facilitated the search for pathogenic viruses in clinical samples. Primers for the polymerase chain reaction can be targeted to unique or conserved regions of the viral genome. While the design of primers must be based on known sequences, it has been demonstrated in bacteria that amplification with primers which hybridize to highly-conserved regions of the genome can be exploited to detect new agents. By taking advantage of sequence conservation among diverse members of a viral genus, we designed PCR primers capable of hybridizing to three different members of the genus Morbillivirus for which sequence information is available. Simultaneous amplification with primers for the porphobilinogen deaminase gene, a constitutively expressed gene in all cells, confirmed the presence of amplifiable RNA. Sequence alignments for the matrix and nucleoprotein genes suggested a highly conserved region of the nucleoprotein gene as a likely target for gene amplification. Morbillivirus primer pairs were chosen from the nucleoprotein gene, which successfully amplified measles virus, canine distemper virus, and phocine distemper virus. In a single reaction which combines cDNA synthesis by reverse transcription of the RNA genome with the polymerase chain reaction (RT PCR reaction), amplification with these primers detected as little as 0.1 pfu (plaque forming unit) of measles virus and 1 TCID50 of canine distemper virus. These Morbillivirus primers can be used to search for novel members of the genus which are likely to share sequence similarity in these highly conserved regions.(ABSTRACT TRUNCATED AT 250 WORDS)
Remote control of DNA-acting enzymes by varying the Brownian dynamics of a distant DNA end

Enzyme rates are usually considered to be dependent on local properties of the molecules involved in reactions. However, for large molecules, distant constraints might affect reaction rates by affecting dynamics leading to transition states. In single-molecule experiments we have found that enzymes that relax DNA torsional stress display rates that depend strongly on how the distant ends of the molecule are constrained; experiments with different-sized particles tethered to the end of 10-kb DNAs reveal enzyme rates inversely correlated with particle drag coefficients. This effect can be understood in terms of the coupling between molecule extension and local molecular stresses: The rate of bead thermal motion controls the rate at which transition states are visited in the middle of a long DNA. Importantly, we have also observed this effect for reactions on unsupercoiled DNA; other enzymes show rates unaffected by bead size. Our results reveal a unique mechanism through which enzyme rates can be controlled by constraints on macromolecular or supramolecular substrates.
IS ATTRACTION FATAL? THE EFFECTS OF HERBIVORE-INDUCED PLANT VOLATILES ON HERBIVORE PARASITISM

We investigated the relationship between parasitoid attraction to herbivore-induced plant volatiles and larval parasitism rates of two closely related heliothine, noctuid moths. Heliothis subflexa Guenee is a specialist on plants in the genus Physalis, while Heliothis virescens Fabricius is an extreme generalist. In North America, these species serve as the only known hosts for the specialist parasitoid Cardiochiles nigriceps Vierick; oviposition into Helicoverpa zea, a non-host, does occur but results in lethal encapsulation of C. nigriceps' eggs. Heliothis virescens larvae are parasitised by C. nigriceps far more frequently than are H. subflexa larvae. Parasitoid attraction to volatiles emitted by tobacco in response to herbivory by H. virescens has previously been demonstrated. Using field experiments, we examined the possibility that pre-detection defenses against parasitoid attraction to herbivore-induced plant volatiles are responsible for H. subflexa's relatively low rates of parasitism by C. nigriceps. Herbivore-damaged plants were significantly more attractive to C. nigriceps than were larvae, larval frass, larval saliva, or damaged leaves alone. Plant species affected parasitoid attraction: tobacco was the most preferred plant species, followed by Physalis angulata, and then cotton. The parasitoid was also more attracted to host species (H. subflexa and H. virescens) than to the non-host species, H. zea. There was an interaction between plant species and herbivore species: each plant species was most attractive when infested by its typical herbivore (e.g., H. virescens on tobacco). We compared these data with those of a previously published experiment on field parasitism of H. virescens and H. subflexa, conducted at the same time and place. Our results indicate that differences in parasitoid attraction to herbivore-induced plant volatiles do not contribute to H. subflexa's relatively low parasitism rate. For the generalist, H. virescens, rates of attraction correspond with rates of parasitism; for the specialist, H. subflexa, they do not. Attraction to H. subflexa on P. angulata is greater than to H. virescens on P. angulata, yet parasitism of H. subflexa is much less than parasitism of H. virescens. These results indicate that pre-detection defenses are not responsible for H. subflexa's low parasitism on P. angulata.
Induction of the Cyp1a-1 dioxin-responsive enhancer in transgenic mice

Cyp1a-1, whose product, aryl hydrocarbon hydroxylase, assists in detoxification of polycyclic aromatic hydrocarbons, is the best characterized of the murine cytochrome P450 genes. The Cyp1a-1 dioxin-responsive enhancer region has been previously analyzed in vitro and found to induce expression of heterologous genes upon exposure of transfected cells to various aromatic hydrocarbons. A 2.58 kbp DNA fragment containing the Cyp1a-1 enhancer elements and promoter region was coupled to the chloramphenicol acetyltransferase (CAT) reporter gene and used to create transgenic mice. CAT assays were performed on tissues harvested from three different lines of transgenic mice following mock-induction or induction using the aromatic hydrocarbon, 3-methylcholanthrene. Basal levels of expression were detected in the spleen and small bowel of non-induced mice, with little or no expression detected in the liver. Treatment with 3-methylcholanthrene increased hepatic expression levels by as much as 10,000-fold. More modest levels of induction were also recorded in the spleen, small bowel, kidney, and lung. The results indicate that the dioxin-responsive enhancer region functions as a strongly inducible promoter in vivo. Differences in the response to induction between male and female mice suggest that Cyp1a-1 expression may be governed in a gender related manner.