bluuebunny/crossref_metadata_2025 huggingface dataset:
Enuresis: prevalence and associated factors among primary school children in Saudi Arabia
Authors: Kalo B B , Bella H.
Published: September 2010

The aim of this study was to determine the prevalence of enuresis and the factors associated with it among primary school children. This is a cross‐sectional population‐based study. Data were collected using a self‐administered questionnaire. Six hundred and forty school children aged 6–16 years were selected randomly. Enuresis prevalence was 16.3% among boys and 13.8% among girls. The overall prevalence was 15%. Breastfeeding, first born children, family integrity and stability were found to be protective. Stressful life events before the age of 6 years, deep sleep, acute family psycho‐social problems, recurrent urinary tract infection, constipation and congenital defects were found to be strongly associated with enuresis. Enuresis was also found to be associated with family history of enuresis. An important finding is that of the 83 children who had enuresis during sleep, 25 (30.1%) wet their beds during day time sleep (day sleep wetting). The importance of enuresis as a health problem has been affirmed and specific guidelines were suggested.
Docking proteins
Authors: Brummer Tilman , Schmitz‐Peiffer Carsten , Daly Roger J.
Published: September 2010

Docking proteins comprise a distinct category of intracellular, noncatalytic signalling protein, that function downstream of a variety of receptor and receptor‐associated tyrosine kinases and regulate diverse physiological and pathological processes. The growth factor receptor bound 2‐associated binder/Daughter of Sevenless, insulin receptor substrate, fibroblast growth factor receptor substrate 2 and downstream of tyrosine kinases protein families fall into this category. This minireview focuses on the structure, function and regulation of these proteins.
Is there a metallicity gradient in the Large Magellanic Cloud?
Authors: Feast Michael W. , Abedigamba Oyirwoth P. , Whitelock Patricia A.
Published: September 2010

A small but significant radial gradient in the mean periods of Large Magellanic Cloud (LMC) RR Lyrae variables is established from the OGLE-III survey data. This is interpreted as a metallicity gradient but other possibilities are also discussed. Data on the ratio of photometrically selected C- and M-type asymptotic giant branch (AGB) stars in the LMC, kindly provided by M-R. L. Cioni, are reanalysed. Removing the effects of bias leads to conclusions strikingly different to the original ones. There is a slight gradient of the C/M ratio in the inner part of the LMC, which might be due to a very small mean metallicity gradient. In the outer part of the LMC the C/M ratio drops dramatically. The most likely reason for this is that the proportion of older stars increases in the outer regions. The mean metallicity of the inner AGB star population estimated from the C/M ratio is lower than for intermediate age LMC clusters and suggest that this population is in the mean older than the clusters and has a mean age which falls in the LMC cluster age gap.
AGN have underweight black holes and reach Eddington
Authors: King A. R.
Published: September 2010

Eddington outflows probably regulate the growth of supermassive black holes (SMBHs) in active galactic nucleus (AGN). I show that effect of the Rayleigh–Taylor instability on these outflows means that SMBH masses are likely to be a factor of a few below the M–σ relation in AGN. This agrees with the suggestion by Batcheldor that the M–σ relation defines an upper limit to the black hole mass. I further argue that observed AGN black holes must spend much of their lives accreting at the Eddington rate. This is already suggested by the low observed AGN fraction among all galaxies despite the need to grow to the masses required by the Soltan relation and is reinforced by the suggested low SMBH masses. Most importantly, this is the simplest explanation of the recent discovery by Tombesi et al. of the widespread incidence of massive ultrafast X-ray outflows in a large sample of AGN.
Modeling Natural Attenuation of Total BTEX and Benzene Plumes with Different Kinetics
Authors: Suarez Monica P. , Rifai Hanadi S.
Published: September 2010

Natural attenuation has emerged as a potential alternative for remediation of sites contaminated with fuel hydrocarbons. This paper compares the results from modeling the natural attenuation of BTEX (benzene, toluene, ethylbenzene, and xylene) at a coastal site to the results from a benzene model at the same site. Field data for total BTEX and benzene were used to develop model parameters for the Bioplume III site model. A first‐order kinetics expression was used for benzene and an instantaneous expression for BTEX. Modeling results showed shorter cleanup timeframes for benzene than for BTEX. Natural attenuation cleanup times using BTEX and assimilative capacity are 47% to 90% higher than those for benzene alone. Cleanup times for benzene of ∼100 years were estimated from model predictions, whereas predicted cleanup times for BTEX varied between 150 and 200 years.
DISPARITIES IN THE BENEFITS FROM DEMOCRATIC REFORM IN NIGERIA: A GENDER PERSPECTIVE
Authors: OYELERE Ruth UWAIFO
Published: September 2010

There is data evidence that welfare has improved post–democratic reform in Nigeria. However, the distribution or concentration of the benefits in subgroups of the population is unknown. In this paper, the question of differential welfare impacts across and within gender following democratic reform in Nigeria is explored. Two related hypotheses are investigated. First, there is no disparity in the income and returns‐to‐education benefits of democratic reform across genders in Nigeria. Second, there are no within‐gender disparities in the impact of democratic reform on income and returns to education in Nigeria. From the results, both hypotheses are rejected. Though men and women both benefitted from democratic reforms, economically significant within‐ and between‐gender differences exist.
Regional Trade Agreements and Democracy Promotion: Measuring the Influence of Democracy Requirements in Regional Trade Agreements
Authors: COLLINS STEPHEN D.
Published: September 2010

This article examines the capacity of regional trade agreements (RTAs) to assist and foster democracy in their respective regions. While the principal raison d'être of RTAs is to stimulate economic growth among its member states, several regional trade associations have embedded democratic requirements into their governance documents. These requirements elevate democracy to a fundamental value of the associations, and mandate (in most instances) that both current and candidate members possess and uphold democratic political systems and practices. This article examines the regional impact of democracy requirements in trade blocs by exploring four leading RTAs: the European Union, NAFTA Mercosur, and ASEAN. The article finds that the ability to promote democracy is impacted by three primary RTA characteristics: (1) the material benefits of membership; (2) the intensity of political and economic integration among member states; and (3) the level of democratic consolidation exhibited by member states.

Este artículo examina la capacidad de los acuerdos comerciales regionales para ayudar y fomentar la democracia en sus respectivas regiones. Mientras que la principal razón de ser de los acuerdos comerciales es la de estimular el crecimiento económico entre sus estados miembros, muchas asociaciones comerciales regionales han incluido requerimientos democráticos dentro de sus documentos de gobierno. Estos requerimientos elevan a la democracia como un valor fundamental de las asociaciones, y ordenan que (en la mayoría de los casos) tanto los estados miembro como los candidatos, posean y mantengan los sistemas políticos democráticos y sus prácticas. Este artículo examina el impacto regional de los requerimientos de la democracia en bloques comerciales al explorar cuatro acuerdos comerciales regionales destacados: la Unión Europea, TLCAN, Mercosur, y ASEAN. El estudio encuentra que la habilidad de promover la democracia es influida por tres características de dichos acuerdos: (1) los beneficios materiales de la membresía; (2) la intensidad de la integración política y económica entre sus miembros; y (3) el nivel de la consolidación democrática demostrada por sus estados miembros.
Reproductive aging in invertebrate genetic models
Authors: Tatar Marc
Published: September 2010

The invertebrate genetic systems of Caenorhabditis elegans and Drosophila melanogaster are emerging models to understand the underlying mechanisms of reproductive aging and the relationship between reproduction and lifespan. Both animals show progressive decline in egg production beginning at early middle age, caused in part by reduction in germline stem cell proliferation as well as in survival of developing eggs. Molecular genetic analysis reveals that insulin and TGF‐β signaling are regulators of germline stem cell maintenance and proliferation during aging. Furthermore, the lifespan of both C. elegans and D. melanogaster appears to be regulated by signaling that depends on the presence of germline stem cells in the adult gonad. These invertebrate models provide powerful tools to dissect conserved causes of reproductive aging.
Ovarian aging in developmental and evolutionary contexts
Authors: Finch Caleb E. , Holmes Donna J.
Published: September 2010

Evolutionary theory predicts that aging‐related fertility declines result from tradeoffs between reproduction and somatic maintenance. Developmental programs for oogenesis also contribute to variation in aging‐related reproductive declines among female vertebrates. Documented reproductive aging patterns in female vertebrates, including humans, are consistent with canonical aging patterns determined developmentally and require no special adaptive explanation. Here we discuss patterns of aging‐related ovarian decline in diverse female vertebrates, and place human ovarian aging in comparative context. Depletion of finite oocyte stores accompanied by fertility loss occurs in a variety of nonhuman mammals and vertebrates, including short‐lived rodents, birds, and some fishes; moreover, postreproductive lifespans of considerable length clearly are not limited to long‐lived, social species with well‐developed kin networks. We argue for a more rigorous comparative approach for understanding the evolutionary and developmental bases of ovarian aging in vertebrates with a wider range of aging patterns and social structures.
Factors influencing the growth and survival of larval and juvenile echinoids
Authors: Kalam Azad Abul , McKinley Scott , Pearce Christopher M.
Published: September 2010

Many factors can influence the growth and survival of larval and juvenile echinoids (e.g. diet type, food ration, stocking density, temperature, salinity, dissolved oxygen, water chemistry and settlement cues), but most of these factors have not been studied in detail with regard to most species targeted for commercial aquaculture production. This review summarizes the state of knowledge on factors influencing the growth and survival of larval and juvenile echinoids. Sea‐urchin larvae are typically reared with either Dunaliella tertiolecta Butcher or Chaetoceros spp. The optimum food ration is in the range of 3000–9000 cells mL−1 and 20 000–60 000 cells mL−1 for D. tertiolecta and Chaetoceros spp., respectively, the concentration depending on larval stage and stocking density. Larvae have been successfully cultured at densities of 0.25–5.00 individuals mL−1, but the optimum level appears to be 1–2 individuals mL−1. A variety of benthic diatom species, particularly Navicula spp., can serve as the initial food source for young juveniles. Older juveniles may be fed with various species of foliose macroalgae and/or prepared diets. Most research on larval and juvenile echinoids has been done using ambient salinity and temperature, but some work has shown the importance of temperature on growth rate.
Mediating Worlds: The Occult as Projection of the New Woman in Weimar Culture1
Authors: Hales Barbara
Published: September 2010

European women, who were experiencing political and social emancipation in the period following the First World War, were also faced with resistance that tried to define their place using traditional roles. Weimar Germany's “New Woman” had thus been expected to continue to perform as wife and mother despite her participation in the masculine world of the workforce. Unable to completely fulfill either of these roles in this transitional period, the modern woman assumes what Mary Douglas identifies as an ambiguous sociological position. In this article, I read the social backlash against the New Woman into a study of women's participation in the occult as seen in various Weimar cultural works including Mary Wigman's expressive dance and Richard Oswald's 1919 film, Unheimliche Geschichten.
Ethnic Irony: The Poetic Parabasis of the Promiscuous Personal Pronoun in Yoko Tawada's “Eine leere Flasche” (A Vacuous Flask)1
Authors: Kim John Namjun
Published: September 2010

First‐person narratives written under the sign of ethnicity are said to be not only “autobiographical” but also “abject.” Rereading the short but seminal and permanently inseminating text, “Eine leere Flasche” by the German Japanese author Yoko Tawada, this article argues for an alternative account of the literary conjunction of first‐person writing and the social figure of ethnicity. The textual figure of the ethnicized first‐person narrator need not be read as an “abject” or even “autobiographical” reproduction of the social figure of “ethnicity.” Rather, in Tawada's poetic practice, the narrative “I” is a permanent parabasis, a material mark of textual irony interrupting the most basic form of prosopopoeia available in Indo‐European languages, the first‐person pronoun. Drawing upon Leslie Adelson's work on German literatures of migration through Paul de Man's work on “autobiography” and its textual irony, this article proposes that the poetically textual trope of irony and the socially contextual figure of ethnicity together constitute what Adelson calls a “riddle of referentiality,” in which neither this trope nor this figure can be confused with the other, yet also not read apart from each other. This article concludes that the social figure of the “ethnic” and the textual trope of irony are indistinguishable from each other. Its proposed notion of “ethnic irony” thus constitutes a pleonasm.
Fluid Flow Aspects in the Formation and Removal of Dross During Plasma-Torch Cutting
Authors: Lawton J. , Mayo P. J.
Published: September 2010

The mechanism of formation of top and bottom dross during plasma cutting were studied and a theory was developed for the case of top dross which agrees well with experiment. Techniques were developed, involving secondary gas flows around the plasma jet and a rotating brush following the plasma jet, which very greatly reduced top-dross formation. Similarly the use of jets under the cut was shown to reduce under-dross to negligible proportions. Thus, by using these techniques, the quality of plasma cutting can be greatly improved and the speed greatly increased without the formation of excessive top dross. Tests done with thin gage stainless steel were successful and are described in detail.
The Fabricability and Toughness of Laminar Composites of Maraging Steel
Authors: Floreen S. , Kenyon N. , Hayden H. W.
Published: September 2010

Laminar composites were prepared of outer layers of 18Ni (200) maraging steel with various inner layer materials. The composites showed reasonable fabricability in both hot and cold working operations. The materials were weldable, and the composite structure could be continued through the weld zone using conventional welding techniques. Yield strengths on the order of 200 ksi were obtained along with excellent crack stopping ability in impact, fracture toughness, stress-corrosion, and fatigue loading. In general, good combinations of fabricability and crack stopping ability can be achieved through the use of soft, relatively thick internal layers that are well bonded to the outer layers.
Increasing the Fatigue Strength of Loaded Holes by Dimpling
Authors: Shewchuk J. , Roberts F. A.
Published: September 2010

A new approach to improving the fatigue resistance of loaded holes in sheet material is presented. The material is first dimpled centering about the region where the hole is to be made, thus introducing tensile plastic strain. The dimple is then flattened and the hole drilled so that the region around the hole is under residual compressive stress. Zero to tension fatigue tests indicate considerable improvement in the fatigue strength of loaded holes as a result of dimpling. A fatigue strength improvement factor of nearly three for 106 cycles to failure was obtained based on the median lives of nominally 0.050-in. thick 2024-T3 aluminum alloy specimens.
Radiative Flame Cooling for Reduction of Nitric Oxide Emissions
Authors: Balakrishnan A. , Edwards D. K.
Published: September 2010

The effect of soot upon heat transfer in combusting gases is investigated. The medium considered is a turbulent gas-soot mixture contained in a plane parallel enclosure. The nongray radiative nature of the soot and the effects of the geometrical configuration are taken into account using an “internal” or “modified” slab emissivity especially developed for the purpose. The simultaneous turbulent transport and radiation are treated with full nonlinearity. It is shown that small amounts of soot greatly aid the radiative cooling of combustion gases, which undergo microrecirculation by turbulent mixing. Larger amounts of soot increase combustion temperature and hence unwanted nitric oxide emissions.
Local Free Convection to Non-Newtonian Fluids From a Horizontal, Isothermal Cylinder
Authors: Gentry C. C. , Wollersheim D. E.
Published: September 2010

An experimental investigation of local free convection heat transfer rates from a horizontal, isothermal cylinder to non-Newtonian, power-law fluids has been conducted. Experimental data were obtained employing a cylindrical test section 2.304 in, dia and 8.018 in. long, constructed of twenty aluminum segments each independently, electrically heated. Non-Newtonian fluids utilized included four aqueous, carboxypolymethylene solutions. Both local and average Nusselt number results were compared with theoretical and empirical models.
Experimental Study of Film Condensation From Steam-Air Mixtures Flowing Downward Over a Horizontal Tube
Authors: Rauscher J. W. , Mills A. F. , Denny V. E.
Published: September 2010

Experiments have been performed to study the effects of air on filmwise condensation from steam-air mixtures undergoing forced flow over a 3/4 in. OD horizontal tube. Local condensation rates at the stagnation point are reported for saturation temperatures of 100–150 deg F, bulk to wall temperature differences of 3–30 deg F, bulk air mass fraction 0–7 percent and oncoming vapor velocity 1–6 ft/sec. For pure steam the average value of q/qNu, where qNu is the Nusselt result, was 0.98 ± 0.10, which compares favorably with the value of 1.04 predicted by a theory which accounts for vapor drag. For steam-air mixtures the reduction in heat transfer was found to be in excellent agreement with the theoretical analysis of Denny and South; the average discrepancy in q/qNu was −2.7 percent, while the maximum was 7.1 percent.
Density estimation of Yangtze finless porpoises using passive acoustic sensors and automated click train detection
Authors: Kimura Satoko , Akamatsu Tomonari , Li Songhai , Dong Shouyue , Dong Lijun , Wang Kexiong , Wang Ding , Arai Nobuaki
Published: September 2010

A method is presented to estimate the density of finless porpoises using stationed passive acoustic monitoring. The number of click trains detected by stereo acoustic data loggers (A-tag) was converted to an estimate of the density of porpoises. First, an automated off-line filter was developed to detect a click train among noise, and the detection and false-alarm rates were calculated. Second, a density estimation model was proposed. The cue-production rate was measured by biologging experiments. The probability of detecting a cue and the area size were calculated from the source level, beam patterns, and a sound-propagation model. The effect of group size on the cue-detection rate was examined. Third, the proposed model was applied to estimate the density of finless porpoises at four locations from the Yangtze River to the inside of Poyang Lake. The estimated mean density of porpoises in a day decreased from the main stream to the lake. Long-term monitoring during 466 days from June 2007 to May 2009 showed variation in the density 0–4.79. However, the density was fewer than 1 porpoise/km2 during 94% of the period. These results suggest a potential gap and seasonal migration of the population in the bottleneck of Poyang Lake.
A theoretical framework for quantitatively characterizing sound field diffusion based on scattering coefficient and absorption coefficient of walls
Authors: Hanyu Toshiki
Published: September 2010

This paper describes the development of a theoretical framework for quantitatively characterizing sound field diffusion based on scattering coefficient and absorption coefficient of walls. The concepts of equivalent scattering area, equivalent scatter reflection area, average scattering coefficient and average scatter reflection coefficient are introduced in order to express all walls’ capability of scatter in a room. Using these concepts and the mean free path, scatter-to-absorption ratio, mean scatter time and diffusion time are defined in order to evaluate degree of diffusion of a space. Furthermore the effect of spatial scattering objects to sound field diffusion is formulated. In addition the time variation of specular and scattered components in a room impulse response is formulated. The verification of these characterization methods was performed with computer simulations based on the sound ray tracing method. The results supported that the ideas presented are basically valid.
Shifting fundamental frequency in simulated electric-acoustic listening
Authors: Brown Christopher A. , Scherrer Nicole M. , Bacon Sid P.
Published: September 2010

Previous experiments have shown significant improvement in speech intelligibility under both simulated [Brown, C. A., and Bacon, S. P. (2009a). J. Acoust. Soc. Am. 125, 1658–1665; Brown, C. A., and Bacon, S. P. (2010). Hear. Res. 266, 52–59] and real [Brown, C. A., and Bacon, S. P. (2009b). Ear Hear. 30, 489–493] electric-acoustic stimulation when the target speech in the low-frequency region was replaced with a tone modulated in frequency to track the changes in the target talker’s fundamental frequency (F0), and in amplitude with the amplitude envelope of the target speech. The present study examined the effects in simulation of applying these cues to a tone lower in frequency than the mean F0 of the target talker. Results showed that shifting the frequency of the tonal carrier downward by as much as 75 Hz had no negative impact on the benefit to intelligibility due to the tone, and that even a shift of 100 Hz resulted in a significant benefit over simulated electric-only stimulation when the sensation level of the tone was comparable to that of the tones shifted by lesser amounts.
Experimental validation of alternate integral-formulation method for predicting acoustic radiation based on particle velocity measurements
Authors: Ni Zhi , Wu Sean F.
Published: September 2010

This paper presents experimental validation of an alternate integral-formulation method (AIM) for predicting acoustic radiation from an arbitrary structure based on the particle velocities specified on a hypothetical surface enclosing the target source. Both the normal and tangential components of the particle velocity on this hypothetical surface are measured and taken as the input to AIM codes to predict the acoustic pressures in both exterior and interior regions. The results obtained are compared with the benchmark values measured by microphones at the same locations. To gain some insight into practical applications of AIM, laser Doppler anemometer (LDA) and double hotwire sensor (DHS) are used as measurement devices to collect the particle velocities in the air. Measurement limitations of using LDA and DHS are discussed.
Pattern-matching analysis of fine echo delays by the spectrogram correlation and transformation receiver
Authors: Park Munhum , Allen Robert
Published: September 2010

Among a few previous attempts to model the outstanding echolocation capability of bats, the work by Saillant et al. [J. Acoust. Soc. Am. 94, 2691–2712 (1993)] is, arguably, one of the most frequently referenced studies in which the predictions of spectrogram correlation and transformation (SCAT) model were compared to the results of relevant behavioral experiments. The SCAT model consists of cochlear, spectrogram correlation and spectrogram transformation blocks, where the latter two processes estimate the overall and the fine time delays between the animal’s call and the echoes, given the neural representation of the acoustic signals generated by the cochlear block. This paper first provides a rigorous account of the spectrogram transformation (ST) block. By approximating the neural signals in analytic forms, many aspects of the ST block are explained and discussed in relation to the predictive scope of the model. Furthermore, based on these analytical arguments, the ST block is investigated from a different point of view, interpreted as a pattern-matching process which may operate at the high level of the animal’s auditory pathway.
Annoyance from industrial noise: Indicators for a wide variety of industrial sources
Authors: Alayrac M. , Marquis-Favre C. , Viollon S. , Morel J. , Le Nost G.
Published: September 2010

In the study of noises generated by industrial sources, one issue is the variety of industrial noise sources and consequently the complexity of noises generated. Therefore, characterizing the environmental impact of an industrial plant requires better understanding of the noise annoyance caused by industrial noise sources. To deal with the variety of industrial sources, the proposed approach is set up by type of spectral features and based on a perceptive typology of steady and permanent industrial noises comprising six categories. For each perceptive category, listening tests based on acoustical factors are performed on noise annoyance. Various indicators are necessary to predict noise annoyance due to various industrial noise sources. Depending on the spectral features of the industrial noise sources, noise annoyance indicators are thus assessed. In case of industrial noise sources without main spectral features such as broadband noise, noise annoyance is predicted by the A-weighted sound pressure level LAeq or the loudness level LN. For industrial noises with spectral components such as low-frequency noises with a main component at 100 Hz or noises with spectral components in middle frequencies, indicators are proposed here that allow good prediction of noise annoyance by taking into account spectral features.
Skin Reaction
Authors: Mueller Kristen L.
Published: September 2010

A costimulatory receptor for immune cells in the skin is identified.
Here to Stay
Authors: Hurtley Stella M.
Published: September 2010

Bacterial colonization of the mucosa is facilitated if the microbes engage a human receptor that counteracts epithelial exfoliation.
Looking Ahead to the Past
Authors: Yaffe Michael B.
Published: September 2010

Chief Scientific Editor Michael Yaffe makes his predictions for exciting new areas of signaling-related research.
Targeting a Common Collaborator in Cancer Development
Authors: Myers Andrea P. , Cantley Lewis C.
Published: September 2010

A small-molecule inhibitor of phosphatidylinositol 3-kinase enhances the cytotoxic effects of the common chemotherapeutic agent doxorubicin in breast and ovarian cancer cell lines.
Listeria monocytogenesPrsA2 Is Required for Virulence Factor Secretion and Bacterial Viability within the Host Cell Cytosol
Authors: Alonzo Francis , Freitag Nancy E.
Published: September 2010

In the course of establishing its replication niche within the cytosol of infected host cells, the facultative intracellular bacterial pathogenListeria monocytogenesmust efficiently regulate the secretion and activity of multiple virulence factors.L. monocytogenesencodes two predicted posttranslocation secretion chaperones, PrsA1 and PrsA2, and evidence suggests that PrsA2 has been specifically adapted for bacterial pathogenesis. PrsA-like chaperones have been identified in a number of Gram-positive bacteria, where they are reported to function at the bacterial membrane-cell wall interface to assist in the folding of proteins translocated across the membrane; in some cases, these proteins have been found to be essential for bacterial viability. In this study, the contributions of PrsA2 and PrsA1 toL. monocytogenesgrowth and protein secretion were investigatedin vitroandin vivo. Neither PrsA2 nor PrsA1 was found to be essential forL. monocytogenesgrowth in broth culture; however, optimal bacterial viability was found to be dependent upon PrsA2 forL. monocytogeneslocated within the cytosol of host cells. Proteomic analyses ofprsA2mutant strains in the presence of a mutationally activated allele of the virulence regulator PrfA revealed a critical requirement for PrsA2 activity under conditions of PrfA activation, an event which normally takes place within the host cell cytosol. Despite a high degree of amino acid similarity, no detectable degree of functional overlap was observed between PrsA2 and PrsA1. Our results indicate a critical requirement for PrsA2 under conditions relevant to host cell infection.
Synthesis of isothiocyanates from non-aromatic nitrogen-containing heterocycles
Authors: Gonda Jozef , Kristian Pavol , Mikler Ľubomír
Published: September 2010

Investigation of the reaction of thiophosgene with Δ2-oxazolines I, Δ3-thiazolines II, 4H-benzo[d][1,3]thiazines III, 2-methoxypentahydro-Δ1-azepine IV, theophylline and caffeine showed that only compounds I and IV reacted to give 2-acyloxyethyl isothiocyanates and methyl 6-isothiocyanatohexanoate. The structure of these products was corroborated by IR, 1H NMR, 13C NMR and mass spectral methods. The suitability of the above-mentioned compounds to react is discussed.
On the automodel properties of the counter-current regurlarly stacked trickle bed columns
Authors: Gierczycki Andrzej , Staněk Vladimír , Vychodil Petr , Jiřičný Vladimír , Pikoń Jerzy , Čermák Jan
Published: September 2010

An approach utilizing the automodel properties in describing the hydrodynamic behaviour of counter-current columns has been extended to regularly stacked beds. Two new kinds of the packing have been investigated: The so-called K-packing, developed in the German Democratic Republic and the Cellular packing, developed in Poland. The results of experiments have been presented in the form of plots of the normalized liquid hold-up, hp, versus the normalized liquid velocity, Ql, and two empirical correlations. A comparison with previous results with randomly packed counter-current trickle bed columns has also been made.
Reaction of chromocene with 1,2-ethanediamine and 2,2'-iminobisethanamine
Authors: Kalousová Jaroslava , Beneš Ludvík , Votinský Jiří
Published: September 2010

Reaction of chromocene with excess liquid 1,2-ethanediamine (en) or its vapours in vacuum at room temperature produces the compound [Cr(en)3](C5H5)2. Analogous reaction with 2,2'-iminobisethanamine (det) at 90 °C produces the compound [Cr(det)2](C5H5)2. The most likely bonding arrangement of the two new compounds has been suggested on the basis of results of measurements of their magnetic properties and IR spectra.
Brassinosteroids with a cholestane side chain
Authors: Kohout Ladislav , Strnad Miroslav
Published: September 2010

The synthesis of 2α,3α-dihydroxy-B-homo-7-oxa-cholestan-6-one (VI), 2β,3β-dihydroxy-B-homo-7-oxa-5α-cholestan-6-one (VIII) and 2α,3α-dihydroxy-B-homo-6-oxa-5α-cholestan-7-one (XI) is described. The activity of these brassinosteroids in the bean second internode bioassay is lower than the activity of 24-epibrassinolide (XXI).
Contribution to the study of the kinetics of redox reactions proceeding via electrode processes: Reactions with two-electron transfer
Authors: Macenauer Jaroslav
Published: September 2010

The author studied the kinetics of redox reactions of the type n2Ox1 + n1Red2 ⇄ n1Ox2 + n2Red1 proceeding via electrodes, for the case of two-electron redox systems. The dependence of the reaction time on experimental parameters (resistance, concentration, and volume of reactants) was studied on two model reactions, and the theory was verified.
Transition metal tetracyano complexes, their thermal and sorption properties
Authors: Sopková Anna , Šingliar Michal
Published: September 2010

The possibility of resorption of a guest molecule (G) or its substitution by other compounds is not known for M(NH3)2N(CN)4.2G (G = C6H6) or M(en)mM'(CN)4.nG clathrates, or even for the parent M(NH3)mM'(CN)4.nH2O, MM'(CN4).nH2O tetracyano complexes. These, however, are capable of sorption, and their lattice space can be reversibly or irreversibly filled with a suitable organic compound if the clathrates or tetracyano complexes in the hydrated form are allowed to be in contact with organic substances whose size and polarity fit the tetracyano complex lattice. The space within the lattice, however, develops as early as their formation from solution or suspension in the presence of the compound G (presence of water is actually sufficient).
Effect of the concentration of 5,5'-dithiobis(2-nitrobenzoic acid) on parameters of the kinetics of its chemisorption on thiol derivatives of cellulose
Authors: Breier Albert , Gemeiner Peter , Beneš Milan J.
Published: September 2010

Equations describing the dependence of parameters of sorption kinetics on the sorbate concentration have been determined. The validity of the equations has been verified for the chemisorption of 5,5'-dithiobis(2-nitrobenzoic acid) on bead O-(2-mercaptoethyl)-, O-(3-mercapto-2-hydroxy-propyl)- and O-[2-(4-mercaptophenylsulfonyl)ethyl]cellulose. Isothermic constants obtained from the equations can be calculated also under experimental conditions unfavourable for their determination. These constants may be utilized for characterizing relations between the chemical structure of cellulose derivatives and the sorption process. The equation which provides a complete time-concentration description of sorption is suggested.
Conformation of the A ring in 1-oxo and 3-oxotriterpenoids. Vicinal interproton coupling constants
Authors: Klinot Jiří , Buděšínský Miloš , Klinotová Eva , Vystrčil Alois
Published: September 2010

The coupling constants of the protons on the A ring were determined by full analysis of the spin systems in the 1H NMR spectra of 4,4-dimethyl-5α-cholestan-3-one (XIX) and 1-oxo and 3-oxo triterpenoids I, XIV-XVI, XX and their 2-methyl derivatives V, VI, XVII, XVIII, XXIII and XXIV. from the values of vicinal coupling constants it was inferred that in 2α-methyl-1-oxo and 3-oxo derivatives V, XVII and XXIII the A ring assumes a chair conformation, while in 2β-methyl derivatives VI, XVIII and XXIV a boat conformation. The chair form greatly predominates in 4,4-dimethyl-5α-cholestan-3-one (XIX) and in 1-oxotriterpenoid XX, while in triterpenoid 3-oxo derivatives I, XIV-XVI a significant amount of boat conformation is present at equilibrium (up to 40%). The solvent shifts and the lanthanide induced shifts of the protons on C(2) lead to the same conclusion.
Conformation of ring A in 3-oxotriterpenoids. Dipole moments and CD spectra
Authors: Klinot Jiří , Všetečka Václav , Klinotová Eva , Vystrčil Alois
Published: September 2010

The A ring of 3-oxotriterpenoids allobetulone (I) and 3-xo-lupane-28-nitrile (IV) exists by about 40% in the boat form as derived from comparison of their dipole moments with those of 2α-methyl derivatives II, V (chair models) and 2β-methyl compounds III, VI (boat models). The same result was obtained from the CD spectra of 3-oxotriterpenoids I-VIII and from isomerization of the 2α- and 2β-substituted ketones XI and XII, respectively.
Synthesis and characterization of mercury(II) complexes with diphenylphosphineacetic acid
Authors: Podlahová Jana , Gracias Jiří
Published: September 2010

Complexes of divalent mercury with diphenylphosphineacetic acid (HA) of the composition HgX2(HA)2, HgX2(HA), HgX(A) (HA), HgA2 and Na2HgA4 (X = Cl, Br, I) were synthesized and characterized by means of spectroscopic and further techniques in the solid state and in solution. The coordination environment of mercury is constituted by halides and/or phosphine ligands in tetrahedral arrangement. HA acts as a monodentate P-donor, the A- anion either as a monodentate P-donor (in Na2HgA4) or as a chelating P,O-donot (in the remaining cases).
Study of potential curves by UHF type methods. CH4 molecule and its dissociation products
Authors: Klimo Viliam , Tiňo Jozef
Published: September 2010

Geometry and energy parameters of the individual dissociation intermediate steps of CH4 molecule, parameters of the barrier to linearity and singlet-triplet separation of the CH2 molecule have been calculated by means of the UMP

method in the minimum basis set augmented with the bond functions. The results agree well with experimental data except for the geometry of CH2(1A1) and relatively high energy values of CH(2II) and CH2(1A1) where the existence of two UHF solutions indicates a necessity of description of the electronic correlation by more exact methods of quantum chemistry.
A contribution to evaluation of effects of medium on electronic spectra
Authors: Bekárek Vojtěch , Ševčík Juraj
Published: September 2010

Efficiency has been compared of the Bayliss-McRae-Ooshika, Bakhshiev, and cross term methods in evaluation of the effect of medium on electronic spectra of nine indicators of polarity of medium using also the data obtained in gas phase and in perfluorinated hydrocarbons.
Possible role of nonclassical ions in acid catalysed dehydration of ethanol
Authors: Morávek Vladimír , Ponec Robert
Published: September 2010

On the basis of CNDO/2 calculations,the geometrical changes accompanying the activation of the ethanol molecule in the acid catalysed dehydration have been analysed. The activation of the ethanol molecule via protonation of its hydroxyl group manifests itself above all in the lengthening of the C-O bond. Further elongation of this bond leads to the formation of nonclassical structure, in extreme case to the nonclassical ion which is more stable then the classical one. The above reaction mechanism is confronted with the known facts and provides acceptable unifiying explanation of e.g. the stereoselectivity anomalies and the isotope effect of β-deuterated alcohols as well as other experimental and theoretical data.
Synthesis of potential neuroleptics and tranquillizers: 2-(tert.Amino)-9-(3-dimethylaminopropylidene)thioxanthenes
Authors: Kmoníček Vojtěch , Svátek Emil , Holubek Jiří , Protiva Miroslav
Published: September 2010

4-Dimethylamino-, 4-pyrrolidino-, 4-piperidino-, 4-morpholino- and 4-(4-methylpiperazino)-thiophenol (IIIa-IIIe), which were prepared by two methods and characterized as the 2,4-dinitrodiphenyl sulfides IVb-IVe, were transformed by treatment with 2-iodobenzoic acid and copper in aqueous potassium hydroxide to 2-(4-tert.aminophenylthio)benzoic acids (Va-Ve). Cyclization with polyphosphoric acid gave thioxanthones VIa-VIe which were treated with 3-dimethylaminopropylmagnesium chloride to give the diamino alcohols VIIa-VIId. VIIa, VIIc and VIId were dehydrated by heating with dilute sulfuric acid which resulted in mixtures of geometrical isomers of the olefinic bases Ia, Ic and Id. Crystallization of bases or salts led to homogeneous or almost homogeneous (Z)-isomers belonging to the active chlorprothixene series. The products are devoid of cataleptic and antiapomorphine activities and show only some properties of mild tranquillizers
The study of pressure variations at the bottom of a vibrating plate extraction column
Authors: Stevanović Radomir , Pavasović Vladeta , Simonović Dušan , Nemoda Stevan
Published: September 2010

Pressure changes at the bottom of a vibrating plate extraction column, when single and two liquid phases are flowing through, were analyzed. The model, which describes the action of the forces in the studied system, represents the solution of the macroscopic momentum balance. An experimental procedure for verification of the theoretical considerations consists of the following steps: a) measurement of the pressure drop at the bottom of the extractor, continuous determination of the dispersed phase hold-up, control of the flow rates of liquid phases and characterisation of the perforated plates vibrating motion; b) transfer of the measured data from a tape recorder to the computer system PDP-11, T-34 Digital; and c) development of computer programs for data processing.
Synthesis of the sym-fac-[Co(medien)(S)-Asp]+ isomer and its stereochemical comparison with other ternary cobalt(III) complexes containing (S)-aspartic acid and linear triamine
Authors: Jursík František , Ondráčková Jana , Hájek Bohumil
Published: September 2010

The sym-fac-[Co(medien)(S)-Asp]ClO4 (medien = 4-methyl-1,4,7-triazaheptane) isomer was prepared from [Co(medien)Cl3] and Ag2(S)-Asp in the presence of charcoal. Since sym-fac isomer does not isomerize when equilibrated with charcoal, its formation is of thermodynamic origin. The sym-fac configuration was assigned from electronic, NMR, and circular dichroism spectra. The d-d circular dichroism spectrum which is very similar both in shape and relative intensity to that of the [Co(NH3)3(S)-Asp]+ ion exhibits vicinal contribution from S centre, conformational contributions either from aspartic acid (λ, δ-twist boat) either from medien rings (λ, δ or δ, λ asymmetric envelope). the last contributions are canceled. NMR parameters are consistent with symmetrical conformation which is favoured due to the staggered placement of N-CH3 group with respect to oxygen atoms of aspartic acid. The preferred formation of sym-fac isomer over unsym-fac ones is discussed in relation to the nonbonded interactions of N-CH3 group with Hax of adjacent NH2 group of aspartic acid in each of the two unsym-fac isomers.
Fractionation of soluble portion of reductively alkylated bituminous coals
Authors: Stefanova Maya D. , Lang Ivo
Published: September 2010

Five bituminous coals were reductively alkylated with potassium and 1-butyl iodide in THF. The benzene soluble portion of reductively butylated coals were separated into the saturates, aromatics, neutral heterocyclics, ethers and polar compounds on a silica gel column. From the saturates, the n-alkanes were isolated by the thin-layer and column chromatography on silica gel, and then analyzed by GC. The aromatics were fractionated on a dual packed SiO2/Al2O3 column. The mono- and diaromatic fractions obtained were studied by GC-MS method. The non-hydrocarbon and polar compounds were charcterized by elemental composition, VPO molecular weight and both IR and 1H NMR spectra. The asphaltenes from one reductively butylated coal were fractionated into basic and acidic/neutral parts after bubbling dry HCl gas through their benzene solution. A concept that benzene eluates collect C-alkylation products and diethyl ether + THF mixtures collect the products of O-alkylation was evolved. The ratio of C-alkylation to O-alkylation was found to be a function of the C content of the initial coals.
Further considerations on the calculation of branching redundancies
Authors: Lopez-Gonzalez Juan J. , Martínez-Sánchez Manuel , Fernández-Goméz Manuel , Arenas Juan F.
Published: September 2010

A revision of the general method of Cihla and Pliva to obtain complete redundancy relations for the internal angle deformation coordinates in branched molecules is made. As examples, redundancy conditions are given for octahedral XY6 and trigonal bipyramidal XY5 molecules.
The effect of Co in hydrodesulphurization of 2,3-dihydrobenzo[b]thiophene on Co-Mo catalyst
Authors: Peter Rudolf , Matějec Vlastimil , Zdražil Miroslav
Published: September 2010

Hydrodesulphurization of benzo[b]thiophene and 2,3-dihydrobenzo[b]thiophene on Mo/alumina and Co-Mo/alumina catalysts has been studied in a flow reactor at atmospheric pressure and temperature 543 K. The amount of dihydrobenzo[b]thiophene formed in hydrodesulphurization of benzo[b]thiophene and the amount of benzo[b]thiophene formed in hydrodesulphurization of dihydrobenzo[b]thiophene were much lower on Co-Mo catalyst then on Mo catalyst. The equilibrium constant of the hydrogenation of benzo[b]thiophene to dihydrobenzo[b]thiophene at 543 K was determined. This partial equilibrium was attained during hydrodesulphurization on Mo catalyst irrespectively of the fed sulphur compound but was not approached during hydrodesulphurization on Co-Mo catalyst. Kinetic equation describing simultaneously the reaction of both heterocycles was derived from consecutive hydrogenation-elimination scheme which does not contain step referred to as direct hydrogenolysis of the thiophenic ring. It was concluded that the effect of Co in the reaction network is localized in the section between partially hydrogenated benzothiophene and hydrogen sulphide
A simulation apparatus for the experimental study of batch reactor control methods
Authors: Horák Josef , Beránek Petr
Published: September 2010

A simulation apparatus for the experimental study of the methods of control of batch reactors is devised. In this apparatus, the production of heat by an exothermic reaction is replaced by electric heating controlled by a computer in a closed loop; the reactor is cooled with an external cooler whose dynamic properties can be varied while keeping the heat exchange area constant. The effect of the cooler geometry on its dynamic properties is investigated and the effect of the cooler inertia on the stability and safety of the on-off temperature control in the unstable pseudostationary state is examined.
Nonisothermal control of a batch reactor with exothermic reaction using a mathematical model
Authors: Horák Josef , Beránek Petr , Maršálková Dagmar
Published: September 2010

A method of nonisothermal control of a batch reactor with exothermic reaction is suggested and tested. The control algorithm is based on jump changes in the inlet temperature of coolant, which is chosen so that the highest difference between the temperature of the reaction mixture and the temperature of entering coolant is held at a value near the highest temperature difference at which the stable pseudostationary state still exists. A total model of the system is used for the prediction of the entering coolant temperature.
Phase transfer catalysed N-substitution of 2H-1,2-benzisothiazolin-3-one 1,1-dioxide
Authors: Svoboda Jiří , Paleček Jaroslav , Dědek Václav
Published: September 2010

The title compound on reaction with alkylation reagents and under the conditions of phase catalysis affords 2-substituted 2H-1,2-benzisothiazolin-3-one 1,1-dioxides (III). The conditions of the reaction and the mass spectra of the products are discussed.
Noncataleptic neuroleptic agents: Synthesis of some esters of 2-chloro-10-(4-(2-hydroxyethyl)piperazino)-10,11-dihydrodibenzo[b,f]thiepin
Authors: Jílek Jiří , Valchář Martin , Pomykáček Josef , Dlabač Antonín , Protiva Miroslav
Published: September 2010

Reactions of 2-chloro-10-(4-(2-hydroxyethyl)piperazino)-10,11-dihydrodibenzo[b,f]thiepin (I) with phenylacetic, methoxyacetic, methylthioacetic, phenoxyacetic and morpholinoacetic acid in dichloromethane and in the presence of N,N'-carbonyldiimidazole gave the title esters II - VI. Reaction of I with succinic anhydride afforded the hemisuccinate VII. The esters prepared elicited ataxia in low doses, were low-cataleptic, but only II, IV, and VII proved some antidopaminergic activity in the test using the affecting dopamine metabolism in rat brain striatum.