cssi/SciSciGPT-SciSciNet huggingface dataset:
Transferrin and the Growth-Promoting Effect of Nerves

In addition to its role in the activity of specialized proteins such as hemoglobin and myoglobin, iron is required as a cofactor in several important enzymes common to most animal cells. One such enzyme, ribonucleotide reductase, which regulates the production of deoxyribonucleotides during DNA synthesis, requires a continuous supply of iron to maintain its activity throughout the process of DNA replication. The mechanism by which animal cells normally acquire iron involves receptor-mediated uptake of iron-loaded transferrin, followed by release of apotransferrin. The density of transferrin receptors on the cell surface is greatly increased in rapidly dividing normal and neoplastic cells. Various mitogens and certain organogenic tissue interactions have been shown to induce the appearance of transferrin receptors, signalling the onset of DNA replication. Interference with this process of iron delivery causes the rapid arrest of cell cycling, frequently during the S phase itself, which underscores the importance of iron for DNA replication. Although most circulating transferrin is synthesized in the liver and embryonic yolk sac, smaller quantities are produced in several other embryonic organs and certain other adult tissues. It has been suggested that local synthesis and/or release of transferrin supplies the iron required by rapidly growing cells in situations where the cells do not have ready access to adequate amounts of plasma transferrin due to incomplete development of the vasculature or the presence of blood-tissue barriers (Ekblom and Thesleff, 1985; Meek and Adamson, 1985). Oligodendrocytes and Schwann cells have been shown to synthesize and/or contain high concentrations of transferrin and these cells therefore may constitute a local source of this factor for neurons, whose growth and survival in vitro require transferrin. Transferrin in central and peripheral nervous tissues may be significant for the trophic or growth-promoting effect neurons exert on cells of certain tissues. Transferrin duplicates the activity of neural tissue or neural extracts on growth and development of cultured skeletal myoblasts from chick embryos and on proliferation of mesenchymal cells in blastemas from regenerating amphibian limbs, two systems that have been widely used in investigations of the growth-promoting influence of nerves. Moreover, removal of active transferrin from neural extracts, either with antibodies to transferrin or chelation of the iron, inhibits reversibly the effect of the extract in these developing systems. While the physiological significance of the extract in these developing systems.(ABSTRACT TRUNCATED AT 400 WORDS)
Optical absorption enhancement in silicon nanowire and nanohole arrays for photovoltaic application

We simulate the optical properties of silicon nanowire and nanohole arrays using the transfer matrix method. For optimized parameters, the structures are more absorptive than an optimal single-layer AR-coated thin film.
Relativistic and Quantum Electrodynamic Effects on Atomic Inner Shells

In this chapter our aim is to describe efforts to develop a consistent and accurate theory of atomic inner shells which includes both relativistic and quantum-electrodynamic (QED) effects. We begin with a brief historical description of these efforts in Sec. 1 and continue with more detailed discussions of various theoretical considerations.
Invasion of maritime chaparral by the introduced succulentCarpobrotus edulis : The roles of fire and herbivory.

Invasion by the alien succulent,Carpobrotus edulis, has become a common occurrence after fire in maritime chaparral in coastal California, USA. We studied post-burnCarpobrotus establishment in chaparral that lackedCarpobrotus plants before the fire and compared seedbank and field populations in adjacent burned and unburned stands.Carpobrotus seeds were abundant in deer scat and in the soil before burning. Burning did not enhance germination: many seeds were apparently killed by fire and seed bank cores taken after fire revealed no germinable seeds. Laboratory tests showed that temperatures over 105°C for five minutes killedCarpobrotus seeds. In a field experiment involving use of herbivore exclosures, we found that herbivory was an important source of mortality for seedlings in both burned and unburned chaparral. All seedlings, however, died outside of the burn regardless of the presence of cages. Establishment there is apparently limited by factors affecting plant physiology. In the burned area, seedlings that escaped herbivory grew very rapidly. Overall, it appears that herbivory limited seedling establishment in both burned and unburned sites but that the post-burn soil environment supportedCarpobrotus growth in excess of herbivore use, thus promoting establishment.
Chasm Between Students and Ideological and Political Workers and Its Countermeasures: A Case Study on the Emerging Social Network Site

The electronic time has brought convenience to college students and at the same time it causes quite a number of issues. One is that the previous conventional face-to-face communication with ideological and political workers, represented by counselors has been replaced by texts, phone calls and messages, which are time-saving. These ways would diffuse awkward situations that might happen during communication but also lead to a wide gap between students and ideological and political workers. This article aims to discuss the mechanism of the problem and countermeasures to solve it.
The Effect of Vasoactive Intestinal Polypeptide on Gastric Acid Secretion Is Predominantly Mediated by Somatostatin

The mechanism of action of vasoactive intestinal polypeptide on gastric acid secretion was examined in the isolated, luminally perfused mouse stomach. Vasoactive intestinal polypeptide caused a weak, transient increase in basal and histamine-stimulated acid secretion and a sustained increase in somatostatin secretion. The sustained increase in somatostatin despite return of acid to basal levels indicated that somatostatin secretion was a direct response to vasoactive intestinal polypeptide and not mediated by intraluminal acidification. The increase in somatostatin secretion was partly responsible for the weak, transient nature of the acid response since incubation with pertussis toxin, which is known to block the inhibitory effect of exogenous and endogenous somatostatin, converted the acid response to a sustained increase throughout the period of stimulation. The inhibitory influence of somatostatin was confirmed with selective vasoactive intestinal polypeptide antagonists. The antagonists inhibited vasoactive intestinal polypeptide-induced somatostatin secretion but caused a sustained increase in acid secretion. The pattern of response implied that somatostatin secretion was more sensitive than acid secretion to vasoactive intestinal polypeptide and vasoactive intestinal polypeptide antagonists and that suppression of somatostatin eliminated the main inhibitory influence on acid secretion. In addition, both vasoactive intestinal polypeptide antagonists inhibited basal somatostatin secretion, implying that input from tonically active vasoactive intestinal polypeptide neurons is responsible, at least in part, for basal somatostatin secretion.
Closing the Achievement Gap Through Teacher Collaboration: Facilitating Multiple Trajectories of Teacher Learning

How should district and school leaders improve education for students traditionally underserved by public education: by increasing control over teaching and curriculum, or by empowering groups of teachers to have more collective autonomy, responsibility, and opportunities for professional learning? The second approach — promoting multiple trajectories of learning among groups of teachers—has advantages, as well as some challenges, as a means of closing various achievement gaps. Sociocultural theory informed our research, as it helped us envision how people who work together create opportunities for the adaptation and learning of new practices while increasing the likelihood that individuals internalize new skills and ways of thinking. Through the analysis of a conversation among teachers about Vickie, an English Language Learner, we examine the larger context of a school's reforms. This analysis illustrates both the possibility and desirability of helping teachers engage in multiple and evolving types of ...
Effect of particle size on the electrocatalysis by carbon-supported Pt electrocatalysts: an in situ XAS investigation

Abstract In situ X-ray absorption studies were done in 1 M HClO 4 , with and without 0.3 M MeOH, on several well-defined carbon-supported Pt electrocatalysts with particle sizes in the range of 25 to 90 A. Data were obtained at several potentials in the range of 0.0 to 1.14 V vs. RHE. The results show that as the particle size is reduced below 50 A, the strength of adsorption of H, OH and C 1 , moieties such as CO is increased. The strong adsorption of OH explains the reduced specific activity for oxygen reduction on small particles. The reduced activity for methanol oxidation on the small particles is due to a combination of the increased strength of adsorption of both CO and OH. The strong adsorption of H at negative potentials on small Pt particles is sufficient to induce reconstruction and morphological changes in the Pt particles. Both XANES and EXAFS data on a 53 A particle at 0.84 V indicate that formation of PtOH is the rate determining step in the oxidation of methanol. All these affects are due to an increase in the number of Pt sites with low coordination on the small particles. © 1997 Elsevier Science S.A.
EFFECT OF THYMECTOMY ON HAMSTERS.

SummaryThe effect of thymectomy at various ages on Syrian hamsters has been investigated. Forty-four per cent of the animals thymectomized and sham-operated at less than 24 hours did not survive the first 3 post-operative weeks. The remaining animals, however, appeared as healthy and survived as long as their control littermates. A mild wasting disease occurred in 10% of the thymectomized and sham-operated animals. The incidence of wasting disease and of lethality was equally distributed in the 2 sexes. Survival of skin homografts was extended in animals thymectomized at less than 24 hours (MST = 14.8 days in contrast to 10.5 days in the controls). Operative mortality and cannibalism were greatly reduced and wasting disease did not occur in animals thymectomized at one week of age and X-irradiated 2 weeks later. In these animals skin homografts survived longer than in any other group in this study (MST = 22 days).
The physiology of a blue stain mold with special reference to production of ethyl acetate.

In the course of a survey of fungi causing blue stain of timber in Duke Forest, in the Spring of 1947, there was isolated from a blue-stained recently-cut stump of short-leaf pine (Pinus echinata Mill.) an ascomycete which produced, in culture, a strong ester odor, commonly described as banana oil odor, suggestive of the lower organic acetates. The present account is concerned with the identity of this fungus and isolation and identification of the odoriferous substance, with an attempt to discover the chemical mechanism of its formation. Few accounts of ester production by fungi appear in the literature. Birkinshaw, Charles, and Raistrick (4) recovered ethyl acetate from cultures of Penicillium digitatum Saccardo. Birkinshaw and Findlay (5) identified methyl cinnamate, methyl p-methoxycinnamate, and an ester of anisic acid in cultures of Lentinus lepideus Fr., and Birkinshaw, Bracken, and Findlay (3) isolated methyl anisate from the metabolic products of Trametes suaveolens (Linn.) Fr. Nord and Vitucci (12, 13) found that L. lepideus produced methyl p-methoxycinnamate from various carbon sources, and attempted to elucidate the mechanism of its formation. Several species of Endoconidiophora have been mentioned in connection with the formation of esters or of ester odors. Lagerberg, Lundberg, and Melin (9) reported "amyl acetate" produc-
Modifications to the Hemagglutinin Cleavage Site Control the Virulence of a Neurotropic H1N1 Influenza Virus

A key determinant of influenza virus pathogenesis is mutation in the proteolytic cleavage site of the hemagglutinin (HA). Typically, low-pathogenicity forms of influenza virus are cleaved by trypsin-like proteases, whereas highly pathogenic forms are cleaved by different proteases (e.g., furin). Influenza virus A/WSN/33 (WSN) is a well-studied H1N1 strain that is trypsin independent in vitro and has the ability to replicate in mouse brain. Previous studies have indicated that mutations in the neuraminidase (NA) gene allow the recruitment of an alternate protease (plasminogen/plasmin) for HA activation. In this study we have identified an additional mutation in the P2 position of the WSN HA cleavage site (S328Y) that appears to control virus spread in a plasmin-dependent manner. We reconstructed recombinant WSN viruses containing tyrosine (Y), phenylalanine (F), or serine (S) in the P2 position of the cleavage site. The Y328 and F328 viruses allowed plaque formation in the absence of trypsin, whereas the S328 virus was unable to form plaques under these conditions. In mice, Y328 and F328 viruses were able to efficiently spread following intracranial inoculation; in contrast, the S328 virus showed only limited infection of mouse brain. Following intranasal inoculation, all viruses could replicate efficiently, but with Y328 and F328 viruses showing a limited growth defect. We also show that wild-type HA (Y328) was more efficiently cleaved by plasmin than S328 HA. Our studies form the foundation for a more complete understanding of the molecular determinants of influenza virus pathogenesis and the role of the plasminogen/plasmin system in activating HA.
A characterization of P2(μ) ≠ L2(μ)

It is shown that P2(μ) ≠ L2(μ) if and only if there exists a probability measure ν with ν ⊥ μ and ‖pz.dfnc;1,ν ⩽ Cz.dfnc;pz.dfnc;2,μ for all polynomials p and a fixed constant C < ∞. The relationship between this method and theorems of Berger and of Carey and Pincus concerning rationally cyclic vectors for powers of nonnormal subnormal Operators is examined.
Peripheral vascular brachytherapy

Abstract Ongoing advances in peripheral endovascular technology have been met with disappointing results because of restenosis within the treated vessel. In particular, stent balloon angioplasty of peripheral vessels has yet to achieve patency rates that approximate conventional treatment in the long term. Recent advances in stent, balloon, and wire construction include the incorporation of radioactive substances in an attempt to ameliorate the inflammatory response provoked by typical endovascular manipulation, a technique termed vascular brachytherapy . γ- and β-isotopes and external beam radiation target the very cell population whose activity results in the development of neointimal hyperplasia. Although most clinical research examining the efficacy of vascular brachytherapy has emerged from the coronary artery literature, the use of vascular brachytherapy also has been examined in the peripheral arterial tree and has shown promising results. Current data indicate that vascular brachytherapy is a safe and accessible adjunctive endovascular maneuver that may improve the short-term patency rate of peripheral endovascular applications. The effects on long-term patency rates remain indeterminate compared to conventional therapy. (J Vasc Surg 2002;35:1041-7.)
Individual differences in response to a stranger: social impulsivity as a dimension of temperament in vervet monkeys (Cercopithecus aethiops sabaeus).

Social impulsivity in response to a stranger was assessed in male vervet monkeys (Cercopithecus aethiops sabaeus) using the Intruder Challenge Test. Vervets (N = 128, ages 3-18 years) were presented with an unfamiliar adult male at the periphery of the home enclosure. An index of impulsivity reflecting variation in the tendency to rapidly approach, engage, and challenge the intruder was derived from factor analysis of behavioral responses. Scale reliability (alpha = .84) and test-retest consistency (intraclass correlation = .83) were high, indicating that this index reliably and efficiently measures a stable aspect of temperament from impulsive to inhibited. Impulsivity scores peaked at age 4, when vervet males typically emigrate from the natal group. The highest ranking males in each group were more likely to score in the moderate range, whereas lower ranking males were more likely to score in the highest (impulsive) or lowest (inhibited) quartiles.
Effects of substrate supplementation with hydroxycholesterol analogues and serum lipoproteins on ovine luteal cell progesterone secretion in vitro: demonstration of prostaglandin F2 alpha luteolytic actions in a defined model system.

In an attempt to establish a defined model system for studies aimed at elucidating the mechanism of PGF2\g=a\action, we examined the effects of medium supplementation with soluble hydroxycholesterol analogues, alone and in combination with ovine luteinizing hormone (oLH) in the presence and absence of PGF2\g=a\' on progesterone secretion by mixed ovine luteal cells in vitro. In short-term cultures (2-6 h), supplementary 22R-hydroxycholesterol (22R-OHC; 0.16\p=n-\20\g=m\gml-1) increased (P < 0.05) progesterone production in a dosedependent manner, whereas similar concentrations of 22S-hydroxycholesterol (22S-OHC) and 25-hydroxycholesterol (25-OHC) had little effect. In incubations of \m=le\24h duration, 22R-OHC (1 \g=m\gml-1) dramatically increased progesterone secretion, whereas oLH (100 ng ml-1) in the presence or absence of PGF2\g=a\(250 ng ml-1) had no consistent effects, alone or in combination with 22R-OHC. In contrast, 22R-OHC (1 \g=m\gml-1) alone had no effect in long-term incubations (72\p=n-\192h), nor did treatment with oLH (100 ng ml-1) in the presence or absence of PGF2\g=a\(250 ng ml-1 ) in the absence of 22R-OHC. Together, however, 22R-OHC and oLH stimulated (P < 0.05) progesterone secretion, a synergistic effect consistently inhibited (P < 0.05) by PGF2\g=a\' Equimolar (2.5 \g=m\moll-1) concentrations of 22R-OHC and homologous serum low- or high-density lipoprotein cholesterol exhibited comparable capacities to maintain progesterone secretion in long-term cultures (24\p=n-\168h), with and without gonadotrophin (oLH or human chorionic gonadotrophin, 100 ng ml-1) stimulation. These data establish 22R-OHC as an effective steroidogenic substrate for progesterone biosynthesis in ovine luteal cells in vitro, exhibit its capacity (when combined with gonadotrophin) to extend the useful life of cultured ovine luteal cells in a manner similar to serum lipoproteins and demonstrate the ability to reproduce PGF2\g=a\-induced luteolytic actions in a defined model system in vitro.
Evaluation of Polycation-Stabilized Lactate Oxidase in a Silica Sol–Gel as a Biosensor Platform

Whereas glucose oxidase and related proteins are encapsulated readily in silica sol–gels, α-hydroxy enzymes such as lactate oxidase (LOx), are reported to be damaged by electrostatic interaction with these matrices. Based on a previous report, poly(ethyleneimine), PEI, was evaluated as a protecting compound under conditions suited to analytical measurements. With LOx and PEI co-encapsulated in a silica sol–gel, the enzyme retained 62% of its initial activity after 20 days. In the absence of PEI, activity was lost during the processing. Batch analytical measurements with enzyme-doped sol–gel yielded a linear response over the range 0.5–2.0 mM lactate and a detection limit of 0.03 mM lactate. Both simple incorporation of LOx in a silica sol–gel and an alternative protection method, blocking the ion-exchange sites on silica with La(III), failed. These negative results supported the hypothesis that the efficacy of PEI was related to its formation of a protective sheath around the enzyme.
On the thermal evolution of the mantle wedge at subduction zones

Abstract We use a 2-dimensional numerical geodynamic model to investigate the evolution of the mantle wedge at subduction zones over a period of 300 Myr following the onset of subduction. A variety of parameterizations of the overriding plate, as well as plate subduction rates and mantle potential temperatures, are considered systematically. The average temperature in the mantle wedge within 120 km of the trench is found to decrease substantially (up to ∼100 °C) over this period, with the most rapid cooling occurring during the first 100 Myr. The observed cooling is not spatially uniform, but rather is concentrated in the uppermost 50 km of the mantle wedge, immediately beneath the overriding plate. Temperatures in the mantle wedge in the vicinity of arc volcanism decrease by as much as >200 °C over the 300 Myr period. This decrease in temperature results in a decrease in the portion of mantle wedge beneath the arc in which hydrous melting can occur, impacting both the distribution of melting within the wedge and likely the composition of erupted melts. The observed variations in temperatures in the subarc portion of the mantle wedge with time are significantly larger than the changes in temperature resulting from inclusion of radiogenic heat production in the overriding plate or a zone of partial coupling between the slab and mantle. The results suggest that the mantle wedge is warmer than predicted by steady state thermal models, which may account in part for the differences between the petrologically determined pressure and temperature of equilibration for arc magmas and predictions of the thermal structure of the mantle wedge obtained from steady state thermal models.
Second breakdown and current distributions in transistors

Abstract A study of second breakdown in transistors, which included the use of temperature-sensitive phosphors to reveal current distributions, has indicated that the susceptibility of the transistor to second breakdown is closely linked to the internal distribution of current or of energy dissipation. The effect of such factors as the base drive and internal structural irregularities on the internal current distribution is described. A better understanding of the role of the base drive in second breakdown has been achieved. This led to a test which was used to distinguish second breakdown from other low voltage modes that have been reported to be different levels of second breakdown.
Accurate characterization of machine compliance for simple compression testing

Correction for machine compliance is an important step in analyzing the data obtained in many mechanical testing procedures. The difficulties associated with compliance correction, as they apply to the simple compression mode of testing, are explored in this paper. The commonly employed approach is to extend the procedure suggested in the ASTM standards for testing high modulus, single-filament materials, which implicitly assumes that the machine behaves as a linear spring with a constant compliance factor. It is shown in this paper that this approach results in different values for the machine compliance factor for different materials. The nonuniqueness of the machine compliance factor is attributed to the inherent nonlinearity of the machine compliance, i.e., the nonlinear dependence of the nonsample displacement on the applied load. Through a set of mechanical tests on a range of materials, it has been demonstrated that it is necessary to characterize this nonlinear compliance relationship for the machine to obtain accurate and consistent measurements.
The effects of ion-exchange filter papers and of heavy atoms on room-temperature phosphorescence of several indoles

Abstract Room-temperature phosphorescence (r.t.p.) of twelve indoles on different ion-exchange filter papers is examined. Anion-exchange filter paper Whatman DE-81 gives the largest r.t.p. signals in the presence of iodide; S & S 903 paper treated with diethylenetriamine-pentaacetic acid or supported carboxymethylcellulose resin are less useful. The heavy atom effect is necessary to observe analytically useful r.t.p. signals of indoles, with the trend iodide > thallium(I). Lifetimes of the r.t.p. of indoles are very short, in the millisecond range, and show two components. Absolute limits of detection between 0.2 and 14 ng show r.t.p. to be sensitive and simple analytical technique for these compounds.
A comparison of sampling strategies for computing general sweeps

Sweeping moving objects has become one of the basic geometric operations used in engineering design, analysis and physical simulation. Despite its relevance, computing the boundary of the set swept by a non-polyhedral moving object is largely an open problem due to well-known theoretical and computational difficulties of the envelopes. We have recently introduced a generic point membership classification (PMC) test for general solid sweeping. Importantly, this PMC test provides complete geometric information about the set swept by the moving object, including the ability to compute the self-intersections of the sweep itself. In this paper, we compare two recursive strategies for sampling points of the space in which the object moves, and show that the sampling based on a fast marching cubes algorithm possesses the best combination of features in terms of performance and accuracy for the boundary evaluation of general sweeps. Furthermore, we show that the PMC test can be used as the foundation of a generic sweep boundary evaluator in conjunction with efficient space sampling strategies for solids of arbitrary complexity undergoing affine motions.
What Goes On In Our Schools

To carry on a serious dialogue about, let alone to seek to change, American schooling or simply the local elementary school without a rather substantial body of the information implied seems somewhat bizarre. And yet, to do so is virtually a national pastime. In our pseudowisdom, we know what schools need without knowing what they already have and we know what to put into them without knowing what needs to be replaced. As one foundation executive put it, "We don't need more research. We just need to get back to the basics." And many parents appear to be more concerned about how well rather than what
Spermine Synthase Deficiency Leads to Deafness and a Profound Sensitivity to α-Difluoromethylornithine

Male gyro (Gy) mice, which have an X chromosomal deletion inactivating the SpmS and Phex genes, were found to be profoundly hearing impaired. This defect was due to alteration in polyamine content due to the absence of spermine synthase, the product of the SpmS gene. It was reversed by breeding the Gy strain with CAG/SpmS mice, a transgenic line that ubiquitously expresses spermine synthase under the control of a composite cytomegalovirus-IE enhancer/chicken β-actin promoter. There was an almost complete loss of the endocochlear potential in the Gy mice, which parallels the hearing deficiency, and this was also reversed by the production of spermine from the spermine synthase transgene. Gy mice showed a striking toxic response to treatment with the ornithine decarboxylase inhibitor α-difluoromethylornithine (DFMO). Within 2–3 days of exposure to DFMO in the drinking water, the Gy mice suffered a catastrophic loss of motor function resulting in death within 5 days. This effect was due to an inability to maintain normal balance and was also prevented by the transgenic expression of spermine synthase. DFMO treatment of control mice or Gy-CAG/SpmS had no effect on balance. The loss of balance in Gy mice treated with DFMO was due to inhibition of polyamine synthesis because it was prevented by administration of putrescine. Our results are consistent with a critical role for polyamines in regulation of Kir channels that maintain the endocochlear potential and emphasize the importance of normal spermidine:spermine ratio in the hearing and balance functions of the inner ear.
Immediate predominators in a directed graph [H]

We assume a directed graph whose nodes are labeled by integers between 1 and n. The arcs of this graph correspond to the flow of control between blocks of a computer program. The initial node of this graph (corresponding to the entry point of the program) is labeled by the integer 1. For optimizing the object code generated by a compiler, the relationship of immediate predominator has been used by Lowry and Medlock [3]. We say that node i predominates node k if every path from node 1 to node k passes through (i.e. both into and out of) node i. Node j is an immediate predominator of node k if node j predominates node k and if every other node i which predominates node k also predominates node j. It can easily be proved that if k ≠ 1 and node k is reachable from node 1t hen node k has exactly one immediate predominator. In case k = 1, or node k is not reachable from node 1, the immediate predominator of node k is undefined, and the value 0 will be given by the procedure PREDOMINATOR.
Confinement, composition, and spin-coating effects on the glass transition and stress relaxation of thin films of polystyrene and styrene-containing random copolymers: Sensing by intrinsic fluorescence

Abstract The glass transition temperatures ( T g s) of polystyrene (PS) and styrene/methyl methacrylate (S/MMA) random copolymer films are characterized by intrinsic fluorescence, i.e., monomer fluorescence from an excited-state phenyl ring and excimer fluorescence from an excited-state dimer of two phenyl rings. The T g is determined from the intersection of the rubbery- and glassy-state temperature dependences of the integrated fluorescence intensity measured upon cooling from an equilibrated state. With PS, the effects of nanoconfinement on T g and the transition strength agree with results from studies using probe fluorescence and ellipsometry. The T g -nanoconfinement effect is “tuned” by copolymer composition. As S-content is reduced from 100 mol% to 22 mol%, the confinement effect changes from a reduction to an enhancement of T g relative to bulk T g . Intrinsic fluorescence is also a powerful tool for characterizing relaxation of residual stresses. Stresses induced by spin coating affect local conformations, which in turn affect excimer and monomer fluorescence and thereby integrated intensity. The heating protocol needed to achieve apparently equilibrated local conformations is determined by equivalence in the integrated intensities obtained upon heating and subsequent cooling. While partial stress relaxation occurs upon heating in the glassy state, full relaxation of local conformations requires that a film be heated above T g for times that are long relative to the average cooperative segmental relaxation time. For example, in thin and ultrathin films, equilibration is achieved by heating slowly (∼1 K/min) to 15–20 K above T g . Dilute solution fluorescence of PS and S/MMA copolymers is also characterized and compared to reports in the literature.
Preparation of Strontium Titanate Ceramics and Internal Boundary Layer Capacitors by the Pechini Method

High purity, fine-grain size, SrTiO/sub 3/ ceramics were fabricated from powders which were chemically derived by the Pechini method. The preparation is based upon a thermally polymerizable water-ethylene glycol-citric acid system in which a wide range of metal alkoxides, carbonates, and metal salts are soluble. The process is a closed system, and lends itself to the preparation of complex oxides which can contain numerous additives and dopants. In this study, W-doped SrTiO/sub 3/ powders were prepared with various Sr:Ti ratios, and fine grain internal boundary layer capacitors were fabricated by controlled segregation in sintering. Characteristics of the resin, powder, microstructures, and electrical properties are reported. The advantages and disadvantages of this method of chemical preparation for ceramic materials are noted. 4 references, 4 figures, 1 table.
Evaluation of sedimentation rate methodology reveals an unusual pediatric subpopulation with lupus or lupus-like syndrome and hemolytic anemia

Purpose Sedimentaion rate is often used to manage pediatric patients with rheumatologic disease. Most management decisions are dependent on studies which have used Wintrobe or Westergren sedimentation rate methodologies. However, these methods suffer from the need for relatively large amounts of blood and long turn-around times. Determination of sedimentation rate using laser kinetic rate determination has allowed calibration to Westergren methods, low volume of blood needed for testing and very rapid results. We sought to compare the Wintrobe method to the ESR Stat method (kinetic method; HemaTechnologies, Lebanon NJ) to determine suitability of the ESR Stat method for patient testing. Methods We performed a prospective comparison between the traditional Wintrobe and ESR Stat sedimentation rates in consecutive pediatric patients at a tertiary care pediatric hospital. Wintrobe and ESR Stat sedimentation data was fitted using a logarithmic model. Outliers were defined as those samples with ESR Stat sedimentation rates greater
Detecting single infrared photons with 93% system efficiency

Researchers develop a fiber-coupled single-photon-detection system using amorphous tungsten silicide superconducting nanowire single-photon detectors. The system detection efficiency is higher than 90% in the wavelength range between 1520 nm and 1610 nm. The device dark-count rate, timing jitter and reset time are 1 cps, 150 ps and 40 ns, respectively.
Cone size is related to branching architecture in conifers.

Summary The relationship between branch diameter and leaf size has been widely used to understand how vegetative resources are allocated in plants. Branching architecture influences reproductive allocation as well, but fewer studies have explored this relationship at broad phylogenetic or ecological scales. In this study, we tested whether pollen-producing and seed-producing cone size scales with branch diameter in conifers, a diverse and globally distributed lineage of nonflowering seed plants. Branch diameter and cone size were analyzed using multiple regression models and evolutionary models of trait evolution for a data set of 293 extant conifer species within an explicit phylogenetic framework. Branch diameter is a strong predictor of cone size across conifer species, particularly for pollen cones and dry seed cones. However, these relationships are complex in detail because leaf morphology and seed dispersal biology influence the specific ways in which they are expressed. The ubiquity and strength of these scaling relationships across conifers suggest that reproductive and vegetative morphologies are coupled in the group, and it is therefore difficult to disentangle the evolution of cone size from the evolution of branching architecture.
A new method to predict vessel/platform critical dynamics in a realistic seaway

In this paper, a recently developed approach is used that makes use of a closed form analytic solution, which is exact up to the first order of randomness, and takes into account exactly the unpert...
How to Learn Multiple Tasks

The article examines the question of how learning multiple tasks interacts with neural architectures and the flow of information through those architectures. It approaches the question by using the idealization of an artificial neural network where it is possible to ask more precise questions about the effects of modular versus nonmodular architectures as well as the effects of sequential versus simultaneous learning of tasks. A prior work has demonstrated a clear advantage of modular architectures when the two tasks must be learned at the same time from the start, but this advantage may disappear when one task is first learned to a criterion before the second task is undertaken. Indeed, in some cases of sequential learning, nonmodular networks achieve success levels comparable to those of modular networks. In particular, if a nonmodular network is to learn two tasks of different difficulty and the more difficult task is presented first and learned to a criterion, then the network will learn the second, easier one without permanent degradation of the first one. In contrast, if the easier task is learned first, a nonmodular task may perform significantly less well than a modular one. It seems that the reason for this difference has to do with the fact that the sequential presentation of the more difficult task first minimizes interference between the two tasks. More broadly, the studies summarized in this article seem to imply that no single learning architecture is optimal for all situations.
Fear survey schedule: a normative study.

The results for 49 college females show their scores to be higher on the FSS than for college males (n = 64); this sex difference is a general one over a variety of fears. Many of the strongest rep...
Heme protein-induced chronic renal inflammation: suppressive effect of induced heme oxygenase-1.

Heme protein-induced chronic renal inflammation: Suppressive effect of induced heme oxygenase-1. Background Heme oxygenase (HO) is the rate-limiting enzyme in the degradation of heme; its inducible isozyme, HO-1, protects against acute heme protein-induced nephrotoxicity and other forms of acute tissue injury. This study examines the induction of HO-1 in the kidney chronically inflamed by heme proteins and the functional significance of such an induction of HO-1. Methods Studies were undertaken in a patient with chronic tubulointerstitial disease in the setting of paroxysmal nocturnal hemoglobinuria (PNH), in a rat model of chronic tubulointerstitial nephropathy caused by repetitive exposure to heme proteins, and in genetically engineered mice deficient in HO-1 (HO-1 -/-) in which hemoglobin was repetitively administered. Results The kidney in PNH evinces robust induction of HO-1 in renal tubules in the setting of chronic inflammation. The heme protein-enriched urine from this patient, but not urine from a healthy control subject, induced expression of HO-1 in renal tubular epithelial cells (LLC-PK1 cells). A similar induction of HO-1 and related findings are recapitulated in a rat model of chronic inflammation induced by repetitive exposure to heme proteins. Additionally, in the rat, the administration of heme proteins induces monocyte chemoattractant protein (MCP-1). The functional significance of HO-1 so induced was uncovered in the HO-1 knockout mouse: Repeated administration of hemoglobin to HO-1 +/+ and HO-1 -/- mice led to intense interstitial cellular inflammation in HO-1 -/- mice accompanied by striking up-regulation of MCP-1 and activation of one of its stimulators, nuclear factor-κB (NF-κB). These findings were not observed in similarly treated HO-1 +/+ mice or in vehicle-treated HO-1 -/- and HO-1 +/+ mice. Conclusion We conclude that up-regulation of HO-1 occurs in the kidney in humans and rats repetitively exposed to heme proteins. Such up-regulation represents an anti-inflammatory response since the genetic deficiency of HO-1 markedly increases activation of NF-κB, MCP-1 expression, and tubulointerstitial cellular inflammation.
Description of Global-Scale Circulation Cells in the Tropics with a 40–50 Day Period

Abstract Long time series (5–10 years) of station pressure and upper air data from stations located in the tropics are subjected to spectral and cross-spectral analysis to investigate the spatial extent of a previously detected oscillation in various variables with a period range of 40–50 days. In addition, time series of station pressure from two tropical stations for the 1890's are examined and indicate that the oscillation is a stationary feature. The cross-spectral analysis suggests that the oscillation is of global scale but restricted to the tropics: it possesses features of an eastward-moving wave whose characteristics change with time. A mean wave disturbance, constructed with data from the IGY, provides additional descriptive material on the spatial and temporal behavior of the oscillation. The manifestation in station pressure consists of anomalies which appear between 10N and 10S in the Indian Ocean region and propagate eastward to the Eastern Pacific. Zonal winds participate in the oscillation...
134: Normative data for sonographically determined amniotic fluid volume at the time of nuchal translucency screening: Using the largest vertical pocket technique

MODEL JUDETTE LOUIS, JOHN HOTRA, JAMES JANISSE, ROBERT SOKOL, CaseMetrohealth Medical Center, Cleveland, Ohio, Wayne State University, Detroit, Michigan OBJECTIVE: We recently reported a strong association between alcohol exposure during human pregnancy and extreme preterm delivery; here, we sought to validate a previously reported murine model to facilitate mechanistic studies. STUDY DESIGN: Nulliparous 10-12 week old female C57BL/6J mice were randomized to one of 20 treatment groups and bred using a timed breeding method. Each mouse received one of four doses of alcohol (0, 4, 5 or 6 grams of alcohol/kg body weight) on one of five gestational days (GD) (GD 10, 15, 16, 17, 18). Cages were monitored every 6h for deliveries. Data were analyzed utilizing a 4x5 ANOVA. RESULTS: The alcohol dose by day of exposure interaction was significant (p 0.015), while the main effects for alcohol dose (p 0.942), and day of exposure (p 0.157) on gestational length were not. Examination of the interaction revealed a differential effect of day of exposure on the control group, compared to the alcohol exposed groups. Among the control group mice receiving no alcohol, the GD 10 group had a significantly longer gestation (mean 20.5) than the GD15 (mean 19.2), 17 (mean 19.4) and 18 (mean 19.3) groups. However, the day of exposure was not related to length of gestation in the alcohol groups (p 0.157). Average length of gestation for the alcohol groups was 19.3 days. CONCLUSION: Failing to confirm a previous study in this murine prenatal alcohol exposure model, no relation to gestational duration was detected. An effect may have been cloaked by an apparent major effect of intubation. Again attempting to confirm this model with additional controls or another dosing method or finding other animal models would facilitate further study of prenatal alcohol exposure and preterm delivery risk.
Optical Damage Effects In Z-Propagating LiNbO 3 Channel Waveguides Fabricated On X- And Y-Cut Substrates

Cambridge, Massachusetts 02139ABSTRACTChannel waveguides produced parallel to the z -axis in x as well as y -cut LiNbO3 by Ti indiffusion are found to display severe optical damage in the formof coupling between TE and TM modes for power levels in the range of 1 -100 microwatts at wavelengths of .633 and .488 microns. Previously,this orientation wasthought to display little or no damage. The effect is manifest by both a steady state power dependent transfer of as much as 30% opticalenergy between orthogonallypolarized modes as well as a transient regenerative switching between these modes seen only in x -cut samples subjected to continuous optical throughput at theabove power levels for a period of 8 -24 hours. A model of the observations is proposed based on photorefractive perturbationsINTRODUCTIONPhotorefractive effects which result in the anomalous behavior of waveguide devices fabricated in LiNbO3 have been widely reported. Such phenomenainclude power induced crosstalk in couplers [1], output drift in Mach -Zehnder interferometers [2], optical branching effects in slab waveguides [3], and TE -TM modeconversion [4].The mechanism responsible for photorefractive phenomena in LiNbO3 is the photoexcitation of Fe(2 +) impurity centers in regions of illumination followedby drift and trapping of the carriers in unilluminated portions of the sample. Due to the spontaneous polarization of the ferroelectric lattice, the Fe impuritiesare imbeddedin an asymmetric potential distribution which results in a net current in the direction of the +c axis for electrons photoexcited from the Fe(2+) impuritystate to theconduction band. Regions of space charge may then be established in the vicinity of an optical waveguide which are able to perturb guided modes through the linearelectrooptic effect. This mechanism for photovoltaic fields directed along the z -axis has been exploited for bulk hologram formation in LiNbO3 [5] and is also themajor source of instability for waveguide devices whose channels are placed perpendicular to the z -axis [2]. A review of photorefractive effects may be found in refs. [6,7].The photorefractive coupling of orthogonally polarized modes strongly suggests the existence of an x -axis directed photovoltaic field. In particular, Gee andThurmond [4] found irreversible TE to TM mode conversion in Ti diffused waveguides placed in the y direction on z -cut LiNbO3 substrates. Lam andYen [8] proposeda theoretical model of these results based on a space- charge field which is 90 degrees out of phase with the interference pattern produced bythe TE and TM modes.The space- charge field then modulates the index of refraction of the media through the electrooptic effect and promotes power transfer between TE and TMmodesthrough the action of the r51 electrooptic coefficient. One may expect the production of an x- directed photovoltaic field in other waveguide orientations as well.
A literature review of low back disorder surveillance measures and risk factors.

Objective. The goal of this literature review was to gain insight into low back disorder risk factors via a critical examination of the surveillance measures and analysis techniques employed in existing literature. Design. Fifty-seven original articles were evaluated and categorized as a function of their surveillance measures. Background. There have been a plethora of articles concerning the causes of low back disorder, yet no specific risk factors are consistently associated with the development of these disorders. It was hypothesized that different low back surveillance measures and variations in risk factor (dependent variable) measurements have led to the inconsistencies in the literature. Methods. Five low back disorder surveillance measures and five risk factor categories were defined for this review. Each article was classified on several criteria including: surveillance measures, risk factors, statistical methods, population and type of study. Summary statistics were calculated for the percentage of positive findings as a function of surveillance measure and risk factor category. Results. The most consistently defined surveillance measure was incidence of low back disorder, with 82% of those investigating it as claims from medical records or Occupational Safety and Health Administration records. The combination of surveillance measures and risk factor influenced the outcome of investigations. Ninety-one percent of the direct or video methods of measuring exposure risk factor influenced outcome. Psychosocial measures had positive findings in 70% of the studies examining lost time. Finally, statistical methodology was critical in the outcome of these investigations. Conclusions. The surveillance measure of incidence had more positive findings, with exposure risk factors and the surveillance measures indicating more advanced stages of low back disorder such as lost time had more positive findings with psychosocial risk factors. Thus, as low back disorders progress to disability, the psychosocial risk factors play a more prominent role. Relevance In order to prevent low back disorders we must first understand the plethora of epidemiological literature. This literature review provides new insight on the critical issues that have contributed to the results of previous research. @ 1997 Elsevier Science Ltd.
Spontaneous Closure of Paravalvular Leak after Mitral Valve Replacement

Complications after prosthetic valve replacement may be multiple. In biologic valves, valve detachment and cusp perforation may occur. If this is of significant magnitude, reoperation may be required. This report describes recurrent mital regurgitation after mitral valve replacement with a Hancock porcine xenograft. The regurgitation subsided spontaneously three months later. We felt that a paravalvular leak closed, with progressive fibrosis and tightening of the annulus. Functional results in this patient were excellent.