cssi/SciSciGPT-SciSciNet huggingface dataset:
Teratogenicity in vitro of 2-acetylaminofluorene: role of biotransformation in the rat.

2-Acetylaminofluorene (AAF), a highly effective mutagen and carcinogen, was tested as a direct-acting teratogen in an embryo culture system. Concentrations of up to 75 μg/ml (336 μM) of AAF produced no detectable malformations and only minimal decreases in viability and growth of rat embryos explanted on day 10 (11th day of gestation; the day after fertilization was designated as day 0). Inclusion of a microsomal monooxygenase system (prepared from rat liver) in the culture medium, however, resulted in marked changes in viability and growth. All explanted embryos exposed to concentrations of AAF above 60 μg/ml (269 μM) plus the microsomal monooxygenase system exhibited readily observable malformations as well as significant decreases in size and macromolecular content. Two metabolites, N-hydroxy-2-acetylaminofluorene (N-OH-AAF) and N-acetoxy-2-acetylaminofluorene (AAAF), each produced malformations in the absence of a monooxygenase system. At concentrations of 25 μg/ml (105 and 88 μM) approximately 50% of the embryos exposed to these metabolites were malformed. The predominant malformations associated with the metabolites were ventrolateral protrusions and hypoplasia of the prosencephalic region, whereas AAF plus the monooxygenase system produced an interruption of neural tube closure. This suggested the possibility that other metabolites may participate in the AAF-induced malformation syndrome. The addition of the monooxygenase system to cultures containing N-OH-AAF or AAAF increased the frequency of malformations without increasing lethality or decreasing growth.
Nicotinamide enhances skin flap survival.

The effects of nicotinamide in an abdominal island pedicle skin flap were examined. A 7×7 crri island pedicle skin flap ligating the left inferior neurovascular pedicle was created on 50 male Sprague Dawley rats (250-275 grams) that were divided into five groups. Animals received either 0.6 cc of saline or doses of nicotinamide for 16 days (14 days preoperatively and 2 days postoperatively): 25 mg b.i.d., 50 mg b.i.d., 100 mg b.i.d. or 200 mg b.i.d. Forty-eight hours postoperatively each animal received 25 mg of Fluorescein via the tail vein. The area of necrosis was visualized and quantified and is presented as % survival. A one factor Fisher PLSD test was performed with a statistical significance of p<0.05 with the results as follows: saline 58.8%, 25 mg 68.6%, 50 mg 82%, 100 mg 80.8%, and 200 mg 86%. From this data it would appear that the angiogenic factor nicotinamide may increase random flap survival.
Analysis of theK-Subband Structure of the ν1Fundamental of Propargyl Radical H2CC≡CH

Abstract The K -subband structure of the acetylenic CH stretch fundamental, ν 1 , of propargyl radical, CH 2 CCH, has been assigned and analyzed. The K = 0, 1−, 1+, 3, 4, 5, and 6 upper state energies totaling 109 levels could be accurately fitted with Watson's fourth-order A -reduced Hamiltonian. The K = 2 subband was perturbed with the level crossing between N = 17 and 18.
Asynchronous Accumulation of Lettuce Infectious Yellows Virus RNAs 1 and 2 and Identification of an RNA 1 trans Enhancer of RNA 2 Accumulation

Time course and mutational analyses were used to examine the accumulation in protoplasts of progeny RNAs of the bipartite Crinivirus, Lettuce infectious yellow virus (LIYV; family Closteroviridae). Hybridization analyses showed that simultaneous inoculation of LIYV RNAs 1 and 2 resulted in asynchronous accumulation of progeny LIYV RNAs. LIYV RNA 1 progeny genomic and subgenomic RNAs could be detected in protoplasts as early as 12 h postinoculation (p.i.) and accumulated to high levels by 24 h p.i. The LIYV RNA 1 open reading frame 2 (ORF 2) subgenomic RNA was the most abundant of all LIYV RNAs detected. In contrast, RNA 2 progeny were not readily detected until ca. 36 h p.i. Mutational analyses showed that in-frame stop codons introduced into five of seven RNA 2 ORFs did not affect accumulation of progeny LIYV RNA 1 or RNA 2, confirming that RNA 2 does not encode proteins necessary for LIYV RNA replication. Mutational analyses also supported that LIYV RNA 1 encodes proteins necessary for replication of LIYV RNAs 1 and 2. A mutation introduced into the LIYV RNA 1 region encoding the overlapping ORF 1B and ORF 2 was lethal. However, mutations introduced into only LIYV RNA 1 ORF 2 resulted in accumulation of progeny RNA 1 near or equal to wild-type RNA 1. In contrast, the RNA 1 ORF 2 mutants did not efficiently support the trans accumulation of LIYV RNA 2. Three distinct RNA 1 ORF 2 mutants were analyzed and all exhibited a similar phenotype for progeny LIYV RNA accumulation. These data suggest that the LIYV RNA 1 ORF 2 encodes a trans enhancer for RNA 2 accumulation.
Synthesis of Organic Salts with Large Second-Order Optical Nonlinearities

A series of organic salts, in which the cation has been designed to have a large molecular hyperpolarizability, has been prepared. Variation of the counterion (anion) in many cases leads to materials with large powder second harmonic generation efficiencies, the highest of which is roughly 1000 times that of a urea reference.
A Monte Carlo study of fluctuating polymer-grafted membranes.

Using Monte Carlo simulations of an off-lattice model, we study the elastic properties of polymer-grafted membranes. Our results are found to be in good agreement with those predicted by the classical path approximation of the self-consistent field theory and scaling theory based on de Gennes’ blob picture. In particular, we found that when the membrane is grafted on both sides by brushes with same molecular weight N and grafting density σ, the excess bending modulus induced by the polymers scales as N3σα where α is consistent with 7/3, as predicted by the self-consistent field theory, and 5/2, as predicted by the scaling theory. When the polymers are grafted to one side of the membrane only, the membrane bends away from the polymers with a spontaneous curvature with a scaling that is consistent with both scaling and self-consistent field theories. When the thickness of the brush exceeds the membrane’s spontaneous radius of curvature, the bending modulus approaches a constant which is of the same order as...
Inversion of Conduction and Valence Bands in Pb 1-x Sn x Se Alloys

Single-crystal films of ${\mathrm{Pb}}_{1\ensuremath{-}x}{\mathrm{Sn}}_{x}\mathrm{Se}$ alloys with rocksalt structure ($0\ensuremath{\le}x\ensuremath{\le}0.33$) have been deposited by evaporation on cleaved (100) faces of KCl substrates. The energy gap ${E}_{g}$ at $T=300, 195, \mathrm{and} 77\ifmmode^\circ\else\textdegree\fi{}$K has been determined by measuring the optical transmission between 2 and 25\ensuremath{\mu}m. As $x$ increases or $T$ decreases, ${E}_{g}$ decreases for sufficiently low values of $x$, but increases for $xg0.2$ and $T=77\ifmmode^\circ\else\textdegree\fi{}$K. The sign reversal in the composition and temperature dependence of ${E}_{g}$ shows that the ${\mathrm{Pb}}_{1\ensuremath{-}x}{\mathrm{Sn}}_{x}\mathrm{Se}$ alloys exhibit the inversion in band structure recently proposed for the ${\mathrm{Pb}}_{1\ensuremath{-}x}{\mathrm{Sn}}_{x}\mathrm{Te}$ alloys. If ${E}_{g}$ is assigned negative values for samples in which the conduction and valence bands are inverted from those in PbSe, the data are well represented by the equation ${E}_{g}=0.13+(4.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}{\mathrm{deg}}^{\ensuremath{-}1}) T\ensuremath{-}0.89x$ eV. The inversion point, at which ${E}_{g}=0$ because the ${{L}_{6}}^{+}$ and ${{L}_{6}}^{\ensuremath{-}}$ band extrema are degenerate, is $x=0.19$ at 77\ifmmode^\circ\else\textdegree\fi{}K and $x=0.30$ at 300\ifmmode^\circ\else\textdegree\fi{}K.
Equivalency of the forms of set 1 of the Depression Adjective Check Lists

Summary.-To study the equivalency of the forms of Set 1 of the Depression Adjective Check Lists a series of 3 x 2 x 2 x 4 repeated-measures analysis of variance were performed on Set 1 completed by three age groups: (1) 162 women and 121 men college students, (2) 206 female and 171 male adolescents, and (3) 233 elderly women and 105 men. Age group means for elderly were lowest and those for adolescents highest and version of checklist (trait means were lower) were significant. As main effect of the Check List forms was not significant, it was concluded that the forms of Set 1 are equivalent. The Depression Adjective Check Lists (DACL) (Lubin, in press, 1981) have been extensively used as brief measures of depressive affect in adolescents, college students, and elderly groups (Lubin, Swearngin, & Seaton, 1992). Originally developed as a state measure ("how you feel today"), a trait version ("how you generally feel") has been presented recently (Lubin, in press). In addition to the general attractive features of brevity, acceptable reliability, and validity (Lubin, in press), alternate (equivalent) forms would address the problem of a practice effect in repeated-measures designs. Intercorrelations among the lists of Sets 1 and 2 consistently have been high, and preliminary analyses of the variances among the lists of both sets have suggested that the lists do not differ among themselves (Lubin, 1981). The purpose of this article is to report extension of the study of the comparability (equivalency) of the lists of Set 1 by presenting data on both state and trait versions of the DACL for three age groups. Method.-Two hundred eighty-three adults (162 women and 12 1 men), 377 adolescents (206 girls and 171 boys), and 338 elderly persons (233 women and 105 men) participated in the study. A series of 3 x 2 x 2 x 4 repeated-measures analyses of variance were performed on the data. Results.-Of the between-subjects effects, only the main effects of group, i.e., adolescents, college students, and elderly persons (F,,,,, = 7.54, p .17), suggesting that the lists of Set 1 of the DACL are equivalent.
Identifying potential keystone species from field data – an example from temporary ponds

Identifying keystone species is essential for understanding community dynamics and preserving species richness. However, few studies have used quantitative, a priori methods to identify potential keystone species. Species known to act as keystones in North Carolina (NC) temporary ponds (Notophthalmus viridescens, eastern newt, and Siren intermedia, lesser siren) were tested to see whether they played the same role in similar habitats in South Carolina (SC). Newts and sirens had no effect on anuran species richness in SC. Instead, another salamander (Ambystoma talpoideum, mole salamander) absent from the NC ponds was identified as a strong keystone in SC. It functioned independently of environmental factors and the densities of other predators. Larval dragonflies (Tramea carolina, Carolina saddlebag) were identified as weak, context-dependent keystones in SC, supporting anuran richness in isolated ponds with very low pH. The results suggest that the identity of keystone species varies, even in similar habitats within a physiographic region.
Clinical Pharmacology of Netilmicin

Pharmacological studies of netilmicin were conducted in 30 cancer patients. After intravenous administration of 50 mg of netilmicin or gentamicin per m(2) over a 1-h period in 10 patients, the mean peak serum concentrations occurred at the end of the infusion and were 7.6 and 7.3 mug/ml, respectively. At 6 h, the mean serum concentrations of both drugs was 1.1 mug/ml. After intramuscular injection of 50 mg of netilmicin per m(2) to each of the same 10 patients, the mean peak serum concentration was 5.5 mug/ml and occurred at 1 h, and, at 6 h, the mean serum concentration was 1.4 mug/ml. The mean proportion of netilmicin excreted in urine during 6 h after intramuscular injection was 55%, and after intravenous injection it was 40.9%. Results were similar with gentamicin sulfate. After administering 60 mg of netilmicin per m(2) intravenously over 30 min every 6 h in 9 patients, the mean peak serum concentration (7.9 mug/ml) occurred at the end of the infusion. The concentration gradually decreased to below 2.0 mug/ml after 4 h. Continuous infusion of 60 mg of netilmicin per m(2) every 6 h after a 60-mg/m(2) loading dose in 11 patients produced levels consistently above 2.9 mug/ml, during the initial 6-h infusion, and levels above 2.0 mug/ml for at least 1 week.
Fragmentation behavior of disaccharides during desorption-ionization

The fragmentation behavior of native and singly derivatized protonated disaccharides were examined by fast ion bombardment Fourier transform mass spectrometry to determine the origin of various fragment ions produced during desorption–ionization. The lack of interfering matrix ions in this technique allowed the investigation of model disaccharides. Three major product ions were observed, corresponding in mass to a loss of H2O, a loss of a monosaccharide unit and a combination of both losses. The oxygen of the lost H2O molecule originates from an oxygen attached to the anomeric carbon. The other two product ions come from two different monosaccharide units and are due to competing processes. The relative ion intensities of these two fragment ions are governed by the basicities of the fragments. The basicity of the reducing end increases when the hemiacetal is converted into the methyl glycoside. This increase in basicity is due to the increased size of the alkyl group and the ability of the alkyl group to prevent the opening of the reducing glycosidic ring.
Pyrazole analogues of porphyrins and oxophlorins

A series of porphyrin analogues with pyrazole rings replacing one of the usual pyrrole subunits have been synthesized. This was accomplished by reacting 1-phenyl, 1-methyl and 1-ethyl pyrazole-1,3-dicarbaldehydes with a tripyrrane in the presence of TFA, followed by an oxidation step. The initially formed phlorin product was sufficiently stable for the N-phenyl system to be isolated and characterized, although the related N-alkyl phlorin analogues were less stable. Attempts to dehydrogenate the intermediary phlorins with DDQ resulted in decomposition, but the N-alkylphlorins could be oxidized with 0.2% aqueous ferric chloride solutions. Although the phenyl-substituted phlorin could not be oxidized under these conditions, it did afford the pyrazoloporphyrin upon treatment with silver acetate under acidic conditions. Oxidations with silver acetate also afforded oxophlorin analogues where the oxo-linkage was selectively formed at the 5-position. The pyrazole-containing porphyrin analogues are cross-conjugated and exhibit only a small degree of diatropic character. The internal CH resonances were observed between 5.27 and 5.87 ppm, while the external meso-protons fell into a range of 6.84–7.88 ppm. The borderline overall aromatic character was attributed to dipolar resonance contributors. Protonation considerably increased the diatropicity and the diprotonated dications formed from these porphyrin analogues gave the internal CH resonance at upfield values of 2.65–3.20 ppm. The aromatic character was enhanced by the presence of an electron-donating alkyl substituent on the nitrogen compared to the phenyl-substituted species. The pyrazoloporphyrins reacted with nickel(II) acetate in DMF, or palladium(II) acetate in acetonitrile, to give the corresponding organometallic derivatives. The metal complexes showed increased diatropic character but protonation afforded nonaromatic cations. The oxophlorin analogues were also nonaromatic in the free base and protonated forms. This work extends our understanding of carbaporphyrinoid systems and provides the first detailed studies on pyrazole-containing porphyrin analogues.
Three-dimensional micromechanical modeling of voided polymeric materials

Abstract A three-dimensional micromechanical unit cell model for particle-filled materials is presented. The cell model is based on a Voronoi tessellation of particles arranged on a body-centered cubic (BCC) array. The three-dimensionality of the present cell model enables the study of several deformation modes, including uniaxial, plane strain and simple shear deformations, as well as arbitrary principal stress states. The unit cell model is applied to studies on the micromechanical and macromechanical behavior of rubber-toughened polycarbonate. Different load cases are examined, including plane strain deformation, simple shear deformation and principal stress states. For a constant macroscopic strain rate, the different load cases show that the macroscopic flow strength of the blend decreases with an increase in void volume fraction, as expected. The main mechanism for plastic deformation is broad shear banding across inter-particle ligaments. The distributed nature of plastic straining acts to reduce the amount of macroscopic strain softening in the blend as the initial void volume fraction is increased. In the case of plane strain deformation, the plastic flow is observed to initiate across inter-particle ligaments in the direction of constraint. This particular mode of deformation could not have been captured using a two-dimensional, plane strain idealization of cylindrical voids in a matrix. The potential for localized crazing and/or cavitation in the matrix is addressed. It is observed that the introduction of voids acts to relieve hydrostatic stress in the matrix material, compared to the homopolymer. It is also seen that the predicted peak hydrostatic stress in the matrix is higher under plane strain deformation than under triaxial tension (with equal lateral stresses), for the same macroscopic stress triaxiality. The effect of void volume fraction on the macroscopic uniaxial tension behavior of the different blends is examined using a Considere construction for dilatant materials. The natural draw ratio was predicted to decrease with an increase in void volume fraction.
Theory of radioisotope scanning.

Abstract The visualization of radioisotope distributions is an increasingly important application of radioisotopes. A general relation is derived, valid for any detecting system, yielding the optimal radioisotope content as a function of resolution, detector efficiency, time duration of scan, and dimensions of the object being scanned. Various collimating systems are considered and isoefficiency curves calculated. The simplest collimator consists of a cylindrical aperture in a lead shield. The use of a tapered aperture improves the sensitivity somewhat for a given resolution. A focusing detector may be constructed by means of a series of tapered apertures aimed at a focal spot. Finally, the detection of annihilation radiation resulting from positron detection is considered. The resolution and efficiency of these collimating systems are compared. Numerous factors modify the general design considerations. The effect of penetration of lead by the γ-rays is considered as well as the effect of finite source sizes and the attenuation of radiation in the object being scanned. Background radiation arises from many sources and results in an effective limit to the amount of radioisotope which can be employed. Examples of single-channel and coincidence scanning techniques are given.
Political Instability And Economic Performance: Evidence from Revolutionary Mexico

What is the relationship between political instability and economic growth? This article examines this question using insights from the new institutional economics applied to a canonical case: revolutionary Mexico. The authors argue that investment and growth during and after the revolution were less affected by political instability than one might predict based on the extant theoretical and empirical literature. They find that while investor expectations, output, and productivity were sensitive to the interdiction of factor and product markets during the years of intense revolutionary violence (1914-17), the periods of political instability before (1910-13) and afterward (1918-34) had relatively minor effects on investor confidence, investments in new plant and equipment, rates of entry and exit by firms, industrial structure, and productivity growth.
Cue selection in discriminative operant conditioning

Stimulus conditions involved in a discriminative operant learning situation were manipulated to determine which cues were being responded to in order to solve the problem. In a situation where the SD and SΔ periods were of equal length and where a bar press resulted in a click of the feeder mechanism only during the SD period it was found that time interval and/or whether or not a bar press resulted in a pellet of food were utilized by S more so than the cue light or the click of the feeder mechanism.
General Relationships Among Plants and Their Alkaloids

A statistical analysis was made of the 3600 species of plants known to contain alkaloids and their 2000 alkaloids to determine distribution by families, diversity of occurrence of individual alkaloids, how the size of the alkaloids (number of carbons) in species may be correlated with habit, habitat, family and geographic location. The categories used for comparison were woody, herbaceous, temperate, tropical, monocot, dicot and native to Australia. Woody-temperate species have larger alkaloids than herbaceous-temperate. All woody, including both temperate and tropical, have larger alkaloids than all herbaceous. In both herbaceous and woody, the strictly tropical and temperate species have larger alkaloids than the sub-tropical and the warm-temperate. Within the herbaceous species, monocot-temperate have much larger alkaloids than dieot-temperate, but those of the dicot-tropical are larger than the monocot-tropical. In families containing 60 or more kinds of alkaloids, there is a tendency for the number of alkaloids having the same number of carbons to follow a normal distribution curve, or, so to speak, for the family to specialize in aklaloids of a given size. The peak, or the size representing the greatest number of alkaloids, is characteristic of the family and varies from 15 to 27 carbons. Caffeine occurs in the largest number of families (14), lycorine in the largest number of genera (30) and berberinc in the largest number of species (89).
The Short Century: Independence and Liberation Movements in Africa 1945-1994

For much of Africa the 20th century was overshadowed by the experience of colonial rule, with politcal independence arriving for most people only in the last 50 years. "The Short Century" is a broad survey of cultural life in Africa from the independence movements through the post-colonial era to the end of apartheid in 1994. Expansive, wide-ranging and illustrated, this book studies achievements in all areas of the performing and fine arts, photography, literature, theatre, architecture, music and film. "The Short Century" includes the works of over 50 artists from the paintings of Mancona and Sekoto during the '50s, through the drawings and theatre projects of William Kentridge up to the installations and video works of Kay Hassan and Oladele A. Bamgboye. The great writers of the continent - Soyinka, Senghor and Cesaire amongst others - Africa's filmmakers, architects and musicians, all of whom left their mark on the process of decolonization, are studied here in depth. Renowned historians and cultural philosophers discuss the background of developments and analyze the ideological strategies employed by Western colonial powers to preserve their grip on African countries and peoples. A chapter on photojournalism supplemented by a detailed chronology of events and political movements presents the main stages of Africa's political history. A comprehensive anthology in the appendix contains some 30 historical documents, such as essays, speeches and political manifestos, shedding light on the key issues of the period.
Prevalence of Ischemic Nephropathy in the Atherosclerotic Population

Available data fail to define the prevalence of ischemic nephropathy or the association of critical renovascular disease (RVD) with renal function in the atherosclerotic population. The data do suggest, however, that critical RVD is prevalent and that the prevalence increases with age, increasing serum creatinine and clinical atherosclerosis at extrarenal sites. Furthermore, our preliminary data suggest that critical RVD may be either the cause or an important superimposed accelerant of renal insufficiency in a larger portion of the atherosclerotic population with renal insufficiency than previously recognized. In this latter group, critical RVD as a cause of renal insufficiency appears to be rapidly progressive and may contribute to end-stage renal disease with increasing frequency. Conclusive definition of the importance of ischemic nephropathy as a contributor to progressive renal insufficiency and end-stage renal disease will require population-based studies that estimate the prevalence of ischemic nephropathy and the natural history of the disease. Presently, renal duplex sonography appears to be the screening test of choice to define critical RVD for such population-based studies.
Raman spectrum of difluorodiazirine

Abstract The Raman spectrum of difluorodiazirine has been re-examined. Four well-defined bands have been found in the low frequency region, which lead to a definitive assignment for all nine vibrational fundamentals of this molecule. The fundamental frequences are (in cm −1 ): ( a 1 ) 1563, 1282, 805, 502; ( a 2 ) 451; ( b 1 ) 1248, 481; ( b 2 ) 1091, 544.
Strong polarization shocks in the interstellar space

Abstract Structure of infinitely strong shocks in a slightly ionized gas, suitable for the interstellar HI region, is discussed. The charge-separation field, in closed form, is obtained by using a bi-modal (beam-continuum) distribution and the Mott-Smith approach.
Biventricular pacing decreases the inducibility of ventricular tachycardia in patients with ischemic cardiomyopathy

Biventricular pacing (BV) has been studied extensively in patients with left ventricular dysfunction. Preliminary studies have shown improvement in hemodynamics and exercise tolerance in this patient population. However, the electrophysiologic effects of BV pacing remain poorly understood. The purpose of this study was to assess the effect of BV pacing on the inducibility of sustained monomorphic ventricular tachycardia (VT) in patients with coronary artery disease. We hypothesized that acute BV pacing reduces the inducibility of sustained monomorphic VT in patients with ischemic cardiomyopathy.
Surface roughening, melting, and faceting

Abstract The spontaneous formation of defects on solid surfaces is expected for purely entropic reasons. It is only in the last 10 years that the rich variety of disordered surface phases and topologically induced phase transitions have been uncovered. Surface roughening, faceting, and surface melting are all defect mediated phase transitions involving the formation of different topological defects. The study of the energetics and structure of these transitions is both fundamental to surfaces science as well as having important implications to an understanding of growth, catalysis, and diffusion mechanisms. It is only recently, with the development of sufficiently accurate experimental techniques, that a wide variety of experimental studies of these phenomena have been carried out. The study of these transitions has opened the door to a microscopic understanding of the shape and stability of solid surfaces. This review attempts to outline both the theoretical and experimental work on surface defect formation on solid surfaces.
An NC algorithm for finding a maximal acyclic set in a graph

An acyclic set in an undirected graph G = (V,E) is a set A ⊆ V(G) such that the induced graph on A is acyclic. A maximal acyclic set (MAS) has the further property that no vertex can be added to it without creating a cycle in the induced graph. We present the first NC algorithm that finds an MAS in any graph, running in time O(log4n) using O((m2 + n)/log n) processors on a EREW PRAM, answering questions raised by Chen and He. Our NC algorithm for finding an MAS in a graph relies on a novel NC algorithm for finding a maximal forest in a hypergraph which may be of independent interest.
Catalytic racemization of optically active complexes: Tris(ethylenediamine)cobalt(III), -platinum(IV), and -rhodium(III) halides

Abstract Catalytic racemization of tris(ethylenediamine)cobalt(III) iodide has been studied in the presence of active carbon, platinum black and silica gel. Exchange studies of the cobalt complex with the 14C-labelled ethylenediamine indicate that the complex first is activated and then racemizes. This process is accompanied by partial decomposition of the complex. Catalytic racemization of tris(ethylenediamine)platinum(IV) and -rhodium(III) also has been studied in the presence of active carbon, platinum black, and silica gel. Exchange studies of the platinum compound with 14C-labelled ethylenediamine were made under experimental conditions similar to those for racemization. No exchange was found to occur during the process. The racemization most probably takes place through an activated six-co-ordinate intermediate.
Petrochemical study of coexisting minerals from low-grade schists, Eastern Shikoku, Japan☆

Ten isofacial blueschist facies rocks were investigated from the Kōtu-Bizan District, eastern Shikoku, Japan, previously mapped by Iwasaki (1963). Twenty of the constituent minerals have been newly analysed, 17 by conventional chemical methods, and 3 by electron microprobe techniques. Combined with 15 previously determined wet chemical analyses of minerals from the same rocks, mineralogical data include a total of: 8 sodic amphiboles; 2 sodic pyroxenes; 9 white micas; 4 chlorites; 6 garnets; and 6 epidotes. Unit cell dimensions and optical properties for the newly analysed minerals have been determined, and available constants for all 35 minerals are tabulated. Chemographic phase relations indicate that the investigated rocks crystallized under physical conditions transitional between greenschist and blueschist facies, but within the latter facies. Intercalations of actinolite-bearing and sodic amphibole-bearing rocks probably result from differences in oxidation state, as demonstrated by graphic analysis; this conclusion agrees with an hypothesis previously proposed by Iwasaki. Element partitioning among coexisting phases has been investigated; these are the lowest-grade metamorphic rocks for which such a study has been undertaken up to the present time. Aluminum, iron, magnesium and manganese appear to show systematic distributions between the mineral pairs sodie amphibole-white mica, sodic amphibole-epidote, white mica-chlorite and white mica-epidote. Non-systematic partitioning of these elements between garnets and the other minerals may be explained in any of three ways: 1. (1) at least some of the garnets are metastable in the present phase assemblages 2. (2) manganese in garnet exerts a profound influence on the partitioning of ferrous iron and magnesium 3. (3) some of the garnets have reached their Mg solubility limit. Petrographic relations support but do not prove the hypothesis of garnet metastability. Mn+++ appears to be diadochic with aluminum and ferric iron, Mn++ with ferrous iron and magnesium in garnets and epidotes, but not in the other minerals studied. Distributions of manganese, calcium and alkalis show apparently systematic equilibrium relations, and pronounced fractionation. Chemical distributions of the elements are explicable on the basis of valencies, ionic radii and sizes of the various structural sites. The observed systematic partitioning of elements among coexisting minerals implies that Kōtu-Bizan blueschists achieved a close approach to chemical equilibrium during the metamorphism, at least in hand specimen sized volumes of rock.
Optical diodes in nonlinear structures with parity-time symmetries

We show that nonlinear optical structures involving a balanced gain-loss profile can act as optical diodes. This is made possible by exploiting the interplay between the fundamental symmetries of parity ( P ) and time ( T ), with optical nonlinear Kerr effects. This unidirectional propagation is demonstrated for the case of a PT -symmetric nonlinear coupler and a PT -symmetric Bragg grating.
Electron micrographs from concentrated solutions of the tobacco mosaic virus protein

Abstract Shadowed metal replicas and freeze-drying can be used to make preparations whose electron micrographs show the molecular particle arrangement in concentrated solutions of the tobacco mosaic virus protein and in films dried from such solutions. Preliminary pictures of such preparations are reproduced showing continuous two-dimensional sheets and other regularities in particle arrangement.
Studies concerning the possible reconstitution of an active cation pump across an artificial membrane.

The cortical tissue of rat brain was fractionated through zonal centrifugation in a continuous sucrose density gradient, yielding a variety of morphologically distinct membrane fragments derived from nerve-end particles possessing variable levels of activity of Na, K-dependent Mg-sensitive ATPase (Na, K-ATPase) and other enzymes. Upon addition of certain of the zonal fractions, particularly those rich in the ATPase and acetylcholinesterase activities, to one side of planar artificial membranes, formed from mixtures of oxidized cholesterol and alkanes and bathed in a solution containing sodium, potassium, and magnesium ions, direct current membrane resistance fell from one to three orders of magnitude. Subsequent addition of ATP to the same side of the membrane to which the ATPase was added (thecis side) led to the development of net short-circuit current flow and open-circuit potential across the membrane (thecis side being negative with respect to thetrans side). Development of the short-circuit current and open-circuit potential is dependent upon the presence of all the substrates of Na, K-ATPase as well as that of the enzyme itself. The net current flow is inhibited and the open-circuit potential discharged by the addition of ouabain to thetrans side of the membrane, of phospholipase A to thecis side, or of trypsin to either side of the membrane. These observations provide circumstantial evidence for the reconstitution of the active cation pump across the artificial bilayer. Efforts to effect a similar reconstitution across membranes of this and other compositions employing Na, K-ATPase preparations from beef heart, beef brain, cat brain, human red cells, rabbit kidney, and rat brain microsomes failed.
Photo-decarbonylation of beta-styryl isocyanates.

β-Styryl isocyanate (1, R H) and its β-methyl- (1, R CH3) and β-phenyl- (1, R C6H5) derivatives underwent both extensive polymerization and the loss of the elements of carbon monoxide upon irradiation at 254 nm in cyclohexane. The formation of 2,5-diphenylpyrazine (3) and indole 4, (R H) from 1, (R - H) and 2,3-dimethyl-5,6-diphenylpyrazine (6) and 2-methylindole (4, R CH3) from 1, (R CH3) provided diagnostic evidence for styryl nitrene (2a) intermediates. The formation of both phenylacetonitrile (5, R H) and α-phenylpropio-nitrile (5, R CH3) was assigned to an initial rearrangement of the residue, C8H6(R)N: (2), into a ketenimine concerted with the elimination of carbon monoxide from 1. Isomerization then produced a nitrile. β3-(β-phenyl)styryl isocyanate (1, R C6H5) gave no product requiring the intermediacy of a nitrene and/or an azirine. The formation of 2,3,4,5-tetraphenylpyrrole (8) was assigned to a dimerization of the isocyanate concerted with or following the elimination of the elements of carbon monoxide and isocyanic acid, and the formation of 3-phenylisocarbo-styril (9) was assigned to a ring-closure of the isocyanate in an excited triplet state. Each isocyanate gave stilbene and trace amounts of oxidative fragmentation into benzaldehyde and benzonitrile. Solvent participation produced benzylcyclohexane and bicyclohexyl. Two unidentified solids, C17H14N2O and C12H14N2O, were obtained from 1, (R CH3).
Are postnatal steroids ever justified to treat severe bronchopulmonary dysplasia

Current evidence does not favour use of corticosteroids as neurological side effects may outweigh the benefits of treatment, except perhaps in critically ill infants with respiratory failure
RANDOM DRIFT OF AN IDEALIZED OIL PATCH

This paper develops a model for the random drift of an idealized oil patch on water due to influences of wind and currents. Probabilistic descriptions for the displacement of the center of mass are derived. The model provides for random shifts in wind direction and its influence on reorienting the oil patch.
An analysis of coded aperture acquisition and reconstruction using multi-frame code sequences for relaxed optical design constraints

We present an investigation of the performance of coded aperture optical systems where the elements of a set of binary coded aperture masks are applied over a sequence of acquired images. In particular, we are interested in investigating code sequences and image reconstruction algorithms that reduce the optical fidelity and hardware requirements for the system. Performance is jointly tied to the mask design, the image estimation algorithm, and the inherent optical response of the system. As such, we adopt a simplified reconstruction model and consider generalized optical system aberrations in designing masks used for multi-frame reconstruction of the imagery. We also consider the case of non-Nyquist sampled (aliased) imagery. These investigations have focused on using a regularized least-squares reconstruction model and mean squared error as a performance metric. Masks are found by attempting to minimize a closed form objective that predicts the mean squared error for the reconstruction algorithm. We find that even with suboptimal solutions that binary masks can be used to improve imagery over the case of an uncoded aperture with the same aberration.
In situ exposures using caged organisms: a multi-compartment approach to detect aquatic toxicity and bioaccumulation

An in situ toxicity and bioaccumulation assessment approach is described to assess stressor exposure and effects in surface waters (low and high flow), the sediment-water interface, surficial sediments and pore waters (including groundwater upwellings). This approach can be used for exposing species, representing major functional and taxonomic groups. Pimephales promelas, Daphnia magna, Ceriodaphnia dubia, Hyalella azteca, Hyalella sp., Chironomus tentans, Lumbriculus variegatus, Hydra attenuatta, Hexagenia sp. and Baetis tibialis were successfully used to measure effects on survival, growth, feeding, and/or uptake. Stressors identified included chemical toxicants, suspended solids, photo-induced toxicity, indigenous predators, and flow. Responses varied between laboratory and in situ exposures in many cases and were attributed to differing exposure dynamics and sample-processing artifacts. These in situ exposure approaches provide unique assessment information that is complementary to traditional laboratory-based toxicity and bioaccumulation testing and reduce the uncertainties of extrapolating from the laboratory to field responses.
Recent Literature on Lichens—187*

AHTI, T. & L. G. BIAZROV. 2001. New records of Cladonia (lichenised Ascomycetes, Lecanorales) from Khangai (Mongolia). Bjulleten’ Moskovskogo Obscestva Ispytatelej Pirody. Otdel Biologiceskij 106: 71–73. [In Russian.] AHTI, T. & S. HAMMER. 2002. Cladonia, pp. 131–158. 3 fig. In T. H. Nash III, B. D. Ryan, C. Gries & F. Bungartz (eds.), Lichen Flora of the Greater Sonoran Desert Region, Vol. I. Lichens Unlimited, Arizona State University, Tempe, Arizona. [42 species treated. New: Cladonia hammeri Ahti sp. nov. (California, Mexico), C. nashii Ahti sp. nov. (California, Mexico), C. subfimbriata Ahti sp. nov. (Mexico, Arizona, California).] ANTONIN, V., B. GRUNA, Z. HRADILEK, A. VAGNER & A. VĚZDA. 2000. Houby, Lisejniky a Mechorosty Narodniho Parku Podyji [Pilze, Flechten und Moose des Nationalparks Thayatal]. Masarykova Univerzita, Brne. 220 pages. [The text throughout is in both Czech and German. In addition to lists of taxa with brief notes, includes introductory section describing the region.] APTROOT, A. 2002. Acrocordia, p. 89. In T. H. Nash III, B. D. Ryan, C. Gries & F. Bungartz (eds.), Lichen Flora of the Greater Sonoran Desert Region, Vol. I. Lichens Unlimited, Arizona State University, Tempe, Arizona. APTROOT, A. 2002. Anisomeridium, pp. 99–101. In T. H. Nash III, B. D. Ryan, C. Gries & F. Bungartz (eds.), Lichen Flora of the Greater Sonoran Desert Region, Vol. I. Lichens Unlimited, Arizona State University, Tempe, Arizona. [4 species treated.] APTROOT, A. 2002. Arthopyrenia, pp. 103–106. In T. H. Nash III, B. D. Ryan, C. Gries & F. Bungartz (eds.), Lichen Flora of the Greater Sonoran Desert Region, Vol. I. Lichens Unlimited, Arizona State University, Tempe, Arizona. [6 species treated.] APTROOT, A. 2002. Distopyrenis, pp. 180–181. In T. H. Nash III, B. D. Ryan, C. Gries & F. Bungartz (eds.), Lichen Flora of the Greater Sonoran Desert Region, Vol. I. Lichens Unlimited, Arizona State University, Tempe, Arizona. [1 species treated.] APTROOT, A. 2002. Julella, pp. 254–256. In T. H. Nash III, B. D. Ryan, C. Gries & F. Bungartz (eds.), Lichen Flora of the Greater Sonoran Desert Region, Vol. I. Lichens Unlimited, Arizona State University, Tempe, Arizona. [3 species treated.] APTROOT, A. 2002. Kirschsteiniothelia, pp. 257–258. In T. H. Nash III, B. D. Ryan, C. Gries & F. Bungartz (eds.), Lichen Flora of the Greater Sonoran Desert Region, Vol. I. Lichens Unlimited, Arizona State University, Tempe, Arizona. [3 species treated.]
West Africanisms in Limonese Creole English

Costa Rican Limonese Creole (LC) is an English-based creole language showing substrate influence from, among other African languages, the Kwa languages of West Africa, in particular from Akan (Ghana). West Africanisms exhibited in LC include: serial verb constructions, reduplication, ideophones, and lexical retentions. The study of West Africanisms in LC contributes to the body of research on substrate influence on West Atlantic Creoles. This is done not from the extreme position that the majority of creole features can be attributed to substrate influence, but, as Mufwene wrote in 1990, that ‘creoles owe their formal features variably to both substrate influence and the bioprogram as well as from superstrate influence’ (p. 3). Substrate influence will be demonstrated through a comparison of LC and Akan morphophonology, morphosyntax, and lexicon.
Active search on graphs

Active search is an increasingly important learning problem in which we use a limited budget of label queries to discover as many members of a certain class as possible. Numerous real-world applications may be approached in this manner, including fraud detection, product recommendation, and drug discovery. Active search has model learning and exploration/exploitation features similar to those encountered in active learning and bandit problems, but algorithms for those problems do not fit active search. Previous work on the active search problem [5] showed that the optimal algorithm requires a lookahead evaluation of expected utility that is exponential in the number of selections to be made and proposed a truncated lookahead heuristic. Inspired by the success of myopic methods for active learning and bandit problems, we propose a myopic method for active search on graphs. We suggest selecting points by maximizing a score considering the potential impact of selecting a node, meant to emulate lookahead while avoiding exponential search. We test the proposed algorithm empirically on real-world graphs and show that it outperforms popular approaches for active learning and bandit problems as well as truncated lookahead of a few steps.
Treatment Effects of a Relationship-Strengthening Intervention for Economically Disadvantaged New Parents

Objective:The purpose of the present study was to evaluate the treatment effects of a relationship skills and family strengthening intervention for n = 726 high-risk, disadvantaged new parents.Meth...
A broadcast system in whose interest? Tracing the origins of broadcast localism in Canadian and Australian television policy, 1950–1963:

The television systems of Canada and Australia are often assumed to be similar if not synonymous. Both are dominated by American imports; rely on a networking of stations; and trace their media sys...
Genetic obesity in rats. II. The effect of food restriction on the metabolism of adipose tissue

Abstract The metabolism of adipose tissue from genetically obese rats (Fatty) and lean animals was studied in two experiments. In the first experiment, food intake was regulated at three levels in Fatty rats. One group ate ad lib., a second group was pair fed to lean controls, and the third group received two-thirds of the food eaten by the lean rats. Serum insulin was reduced by restricting food intake. Fat cells were largest in the ad lib.-fed Fatties and smallest in the lean rats. Lipolysis, as measured by glycerol release, was comparable in lean and Fatty rats. Several lipolytic drugs were as effective in fat from the obese as the lean animals. Metabolism of 14C-glucose with or without insulin was reduced in the tissue from Fatty rats and was not corrected by restricting food intake. In the second experiment, lipolysis and lipogenesis were studied by serial biopsies during starvation-induced weight loss. Rats were allowed to eat for 3 days before each biopsy. Reduction of fat cells to the same size as normals did not restore lipogenesis or lipolysis to normal. Reesterification of fatty acids remained high in all experiments with tissues from Fatty rats.
INFLUENCE OF FIBER-REINFORCED CONCRETE ON RADON CONCENTRATIONS

The influence of construction materials on the atmospheric radon concentration in an underground facility at the Nevada Test Site was examined. Radon (²²²Rn only) concentrations within the supporting fiber-reinforced concrete (fibercrete) and the native soil were quantified and compared. The average activity concentrations of ²²²Rn were 39±1 and 12±1 Bq kg\u-¹ for the native soil and fibercrete, respectively. The average emanation coefficients of ²²²Rn, measured via Lucas cell scintillation, were significantly higher for the cured fibercrete at 0.078±0.029, than for the dried native soil at 0.0053±0.0006. The emanation coefficient for the in situ native soil is estimated to be 0.020±0.004. In situ exhalation rates were also determined using passive-diffusion charcoal canisters. The average exhalation rate for the native material surface was 5.8±0.6 mBq m\u-² s\u-¹. This was significantly higher (\ip= 9×10\u-\u5) than for the fibercrete surface, which exhibited an average exhalation rate of 2.7±0.7 mBq m\u-² s\u-¹. Based on these results, it can be concluded that the addition of fibercrete to wall surfaces reduces the radon concentration in this underground environment.
Systemic treatment of hepatocellular carcinoma: dawn of a new era?

Despite decades of efforts by many investigators, systemic chemotherapy or hormone therapy have failed to demonstrate improved survival in patients with advanced hepatocellular carcinoma (HCC). On the basis of placebo-controlled, randomized phase III trials, sorafenib has shown improved survival benefits in advanced HCC and has set a new standard for future clinical trials. The successful clinical development of sorafenib in HCC has ushered in the era of molecularly targeted agents in this disease, which is discussed in this educational review. Ongoing studies are evaluating the efficacy and tolerability of combining sorafenib with erlotinib and other targeted agents or chemotherapy. Many molecularly targeted agents that inhibit angiogenesis, epidermal growth factor receptor, and mammalian target of rapamycin are at different stages of clinical development in advanced HCC. Combining targeted agents that inhibit different pathways in hepatocarcinogenesis is an area of active investigation. Future research should continue to unravel the mechanism of hepatocarcinogenesis and to identify key relevant molecular targets for therapeutic intervention. Identification and validation of potential surrogate and predictive biomarkers holds promise to individualize patients’ treatment to maximize clinical benefit and minimize the toxicity and cost of targeted agents. We hope that we will continue to improve the efficacy of systemic therapy in advanced HCC in the coming years.