bluuebunny/crossref_metadata_2025 huggingface dataset:
CHEMILUMINESCENCE INVOLVING PEROXIDE DECOMPOSITIONS
Authors: McCapra Frank , Richardson D. G. , Chang Y. C.
Published: January 2008

Abstract— It is a reasonable assumption that many of the known cherniluminescent organic compounds react to give a carbonyl group in an excited state. By extension of this hypothesis we were led to test several substituted acridinium salts. Oxidation of these with hydrogen peroxide in the presence of base resulted in the formation of N‐methylacridone in high yield, and the emission of light from an excited state of this ketone. Mechanisms for this process are discussed. Interest in indole derivatives aroused by the finding of a tryptamine residue in the luminescent cypridina luciferin, in conjunction with the hypothesis mentioned above, has led to an investigation of some indoles, and in particular, the important isolable peroxide of tetrahydrocarbazole. A preliminary account of this work is given.
CHEMILUMINESCENCE OF SOME REACTIONS WITH MOLECULAR OXYGEN
Authors: Stauff Joachim
Published: January 2008

Abstract— Many inorganic oxidation reactions involving a variety of oxidizing agents show chemiluminescence in the spectral region of 400–600 mp. Excited O2O2‐associates are assumed to be the emitting molecules formed by bimolecular recombination of HOxO2‐radicals. Oxidation of sodium sulfite with molecular oxygen in the presence of Cu‐ and Fe‐basic oxides shows chemiluminescence which originates from the reactions of the heavy metal complexes of OH‐ and O, H‐radicals with O2. The simplest way of producing a radical from O2 is by the uptake of one electron. Suitable electron donors, such as hydro‐quinones and semiquinones, emit light if treated with oxygen. In certain organic solvents OH‐ can also act as electron donor. Its presence causes the formation of semiquinones from quinones in the absence of oxygen. The chemiluminescence which is observable upon treatment of alkaline dimethylsulfoxide, dioxane, pyridine‐water and alcohol‐water mixtures with oxygen is also attributable to electron transfer from OH‐ to O2.
A GENERAL HYPOTHESIS TO INTERPRET ‘HIGH ENERGY PHENOMENA’ OF PHOTOMORPHOGENESIS ON THE BASIS OF PHYTOCHROME
Authors: Hartmann K. M.
Published: January 2008

Abstract— It is demonstrated that the high energy reaction of photomorphogenesis (blue‐far‐red reaction) in the case of seed germination and hypocotyl lengthening of Lactuca sativa (L.) ‘Grand Rapids' is a consequence solely of phytochrome. A hypothesis is presented in which all high energy phenomena can be explained on the basis of phytochrome.
THE PHYTOCHROME REACTION IN LEMNA MINOR L.*
Authors: Rombach J.
Published: January 2008

Abstract of the lecture— Multiplication rate and the rate of expansion of fronds of Lemna minor grown on a culture medium with I 3 per cent sucrose and 3 × 10‐6M kinetin is much enhanced by a daily 3 min exposure to red light. Far‐red, given within 3 hr of the red illumination, counteracts the action of the red light. If the interval between the red irradiation and the exposure to far‐red is increased, a gradually smaller part of the action of red light can be counteracted by far‐red (Fig. 1). From the destruction of P730 observed by differential spectrophotometry(1) a much more rapid decrease of the counteracting effect of far‐red after the red illumination was expected. Similar effects have been observed by De Lint et al. (2)
MOLECULAR DETAILS OF PHOTOCHEMICAL TRANSFORMATIONS
Authors: ZIMMERMAN HOWARD
Published: January 2008

Abstract— Photochemical reactions originate from electronically excited species whose structures are often susceptible to description without excessive difficulty. The factors determining the transformations which these species will most likely undergo are less certain. Our approach has been to develop suitable structures for the excited state involved and then to consider pathways requiring accessible energies. Such pathways can be found by molecular orbital and qualitative valence bond reasoning. This approach reasons that successful transformations tend to be minimum energy processes and will proceed with continuous electron redistribution. Conversely, the pathways taken in a photochemical reaction can often be used to cast light on the reactant excited state structure involved. Examples of this approach and of recent photochemical research by the author are given.

Las reacciones fotoquímicas son originadas a partir de especies electrónicamente excitadas cuyas estructuras pueden ser descriptas sin mayor dificultad para un gran número de càsos. Sin embargo los factores que determinan este tipo de transformación no están claros. En este trabajo se han tratado de desarrollar estructuras apropiadas para los estados excitados involucrados en el proceso para luego proponer caminos que requieran cantidades de energía accesibles. Estos caminos pueden ser encontrados a partir de razona‐mientos que involucran orbitales moleculares y nociones cualitativas de Valencia. Este tipo de razonamiento establece que transformaciones sucesivas tienden a ser procesos de mínima energía, que prosequirán con redistribuciones electrónicas continuas. Por otra parte, los caminos tornados en una reacción fotoquímica pueden usarse a menudo para esclarecer la estructura del estado excitado del reactante empleado. Se dan ejemplos de lo expuesto y de una reciente investigación del autor.
CORRELATION OF ORBITAL CLASSIFICATION OF MOLECULAR ELECTRONIC TRANSITIONS WITH TRANSITION MECHANISM: THE AROMATIC AMINES*
Authors: KASHA MICHAEL , RAWLS H. RALPH
Published: January 2008

El par de electrones aislados del heteroátomo tiene dos orbitales; uno de no unión, orbital ‐n, el cual es del tipo s̀y es ortogonal con respecto a los orbitales de los electrones; y otro de union orbital l, que está relacionado con los electrones π, a un grado en que depende del ángulo de torsión entre el eje del orbital l y el orbital 2pπ del anillo aromático vecino. La excitación de electrones a partir de los orbitales n ó l a orbitales de anti‐unión del tipo π es tratada como una transición de transferencia de carga int amolecular. Se desarrolla un detallado análisis teórico del elemento matricial órbita‐spin para una mezcla singlete‐triplete de las promociones 1 a π en anilinas, usando dos centros integrados. El momento de la transición singlete triplete depende del ángulo de torsión entre el eje del orbital 1 y el piano del anillo aromático. Se provee evidencia experimental para predicir la dependencia angular usando una serie de anilinas restringidas estericamente con distintos ángulos de torsion. El recíproco de la vida media de la fosforecencia de estas anilinas tiene una correlación muy satisfactoria con la función teórica, lo cual apoya el uso del elemento matricial spin‐órbita.
AN ULTRAVIOLET PULSE GENERATOR IN THE SUBMICROSECOND RANGE FOR FLASH PHOTOLYSIS STUDIES
Authors: DALESSIO J. T. , PANTALEONE A. , ZAMPACH J.
Published: January 2008

Los métodos experimentales que se emplean en la actualidad par identificar el electrón hidratado y otras especies transientes no pueden extenderse a escala de tiempos más cortos (10‐7–10‐8 seg), que se requiere para la observación de moléculas excitadas de corta vida, que son precursoras de estas especies transientes, sin sustancial desarrollo. Para alcanzar estos tiempos, los pulsos de excitation sean de electrones, rayos X o luz, así como la luz pulsada para el análisis espectro‐fotométrico debe acortarse en varios órdenes de magnitud. Hemos diseñado un generador de luz ultravioleta y visible que emite pulsos menores que 10‐7 seg y potencia de miles de megavatios. El principio básico consiste en aumentar la tensión de chispa hasta próximo a 100 kV y decrecer la capacidad del circuito de descarga como √V, para mantener la energía de la descarga. Suponemos que estos no son los límites finales de intensidad y tiempo. Para obtener pulsos de luz netos, con tiempo de decrecimiento corto y sin cola se han mejorado considerablemente el circuito elétrico y el montaje del generador. Los primeros resultados en el estudio de transientes de corta vida muestran que esta fuente de luz mejorada permite extender el estudio de transientes en la región de 10‐7 seg.
CORRELATION BETWEEN PHOTOCHEMISTRY AND HIGH‐ENERGY RADIATION CHEMISTRY
Authors: HAMMOND GEORGE S. , CALDWELL RICHARD A. , KING JOHN M. , KRISTINSSON HAUKUR , WHITTEN DAVID G.
Published: January 2008

Abstract— The initial interactions between high‐energy radiation and a sample of condensed matter are complex. However, soon after the initial phases the excitation energy appears in well‐known forms: ions, free radicals, and molecular excited states. These excited species are the immediate precursors of the stable chemical products. The nature of the chemically significant excited species can be inferred by studying the chemical changes induced in solutes which have been well characterized in photochemical studies.

Las interacciones iniciales entre radiaciones de alta energía y una muestra de materia condensada son complejas. Sin embargo, Iuego de la faz inicial la energía de excitatión aparace bajo formas bien conocidas: iones, radicates libres y estados moleculares excitados. Estas especies excitadas son las precursoras inmediatas productos dequímicos estables. La naturaleza de las especies excitadas con significado químico puede ser inferida estudiando cambios químicos inducidos en solutos que han sido bien caracterizados en estudios fotoquimicos.
RADIOLYSIS AND PHOTOLYSIS IN THE ADSORBED STATE
Authors: ROJO ENRIQUE A. , MOLINARI MARCELO A.
Published: January 2008

Abstract— Simultaneous irradiation of gases or liquids adsorbed on high‐surface‐area solids of insulator or semiconductor properties frequently produces a considerable increase in radiolysis yields and selective effects in the distribution of products in comparison with those obtained by irradiation of pure substances. This kind of reaction is also sometimes observed when the solid is irradiated before adding the reactant. The results show that part of the energy absorbed by the solid is transferred by some mechanism to the adsorbate and is able to cause its decomposition. In the present paper some of the most representative experiments in the field are analyzed, with special attention on the interpretation of results and proposed reaction mechanisms.

La irradiatión simultanea de gases o líquidos adsorbidos en sólidos de propiedades aisladoras o semi‐conductoras produce en la mayoría de los casos un considerable aumento de productos de radiólisis respecto a los producidos irradiando las substantias puras. Este tipo de reacciones también se produce a veces irradiando el sólido primero y agregando el reactante posteriormente.

Estos resultados muestran que parte de la energía recibida por el sólido es trasmitida por algúsn mecanismo a la fase absorbida y empleada en la desd compositión del adsorbato.

En el presente trabajo se analizan algunas de las experiencias realizadas y se discuten los resultados e interpretaciones. Se discuten asi mismo las posibilidades futuras en este campo.
PHOTOCHEMICAL REACTIONS OF CARBONYL COMPOUNDS IN SOLUTION‐II. PATERNO‐BÜCHI REACTION AND ENERGY TRANSFER
Authors: YANG N. C.
Published: January 2008

Abstract— Photosensitization with sensitizers of various triplet energy levels was applied to the addition of 9‐anthraldehyde to 2,3‐dimethyl‐2‐butene in order to determine the nature of two reactive excited states of 9‐anthraldehyde. The results indicate that they are most likely an upper triplet state (T2) and a singlet excited state of 9‐anthraldenyde. In a separate series of experiments, it was demonstrated that Paterno‐Büchi reactions occur concurrently with energy transfers from the triplet state of carbonyl compounds to simple olefins in high efficiency. The triplet state of simple olefins is likely to have a nonplanar configuration after the energy transfer. The possible mechanisms of such transfers are discussed.

La fotosensitivación con sentivizadores con varios niveles de energia en el estado triplete fué aplicado a la adición de 9‐antraldehido a 2,3 dimetil‐2‐buteno, con el objeto de deteminar la naturaleza de los estados excitados reactivos del 9‐antraldehido. Los resultados indican que son un estado triplete superior (T2) y un estado singulete del 9‐antraldehido. En una serie separada de experimentos se ha demonstrado que las reacciones de Paterno‐Büchi ocurren con transferencias de energía del estado triplete de compuestos carbonílicos a olefinas simples con eflciencia alta. El estado triplete de olefinas simples parece tener una configuración no planar después de la transferencia de energía. Se discuten los mecanismos posibles de esas transferencias.
SOME PHOTOCHEMICAL REACTIONS OF CONJUGATED ACYCLIC OLEFINS
Authors: CROWLEY KEVIN J.
Published: January 2008

Abstract— The photochemical isomerizations of acyclic conjugated olefins are reviewed. Emphasis is given to photoisomerizations of conjugated dienes and trienes, while reference is made to allene formation from, and other isomerizations of, olefins conjugated with other unsaturated groups. The wide variety of products which is obtained on irradiation of differently substituted trienes is outlined. The stereochemical course of some of these reactions is discussed in orbital symmetry terms, and the uitlity of such considerations is considered in the context of the stereochemistry of the four isomers of alloocimene.

En este trabajo se ha efectuado una revisión de los procesos de isomerizaciones fotoquímicas de olefinas conjugadas acíclicas. Se ha dado especial énfasis a las fotodimerizaciones de dienos y trienos conjugados, al mismo tiempo que se hacen referencias a la formación de alenos y a otras isomerizaciones de olefinas conjugadas con otros grupos no saturados. Se describe lagran variedad de productos obtenidos por irradiación de trienos con distintas sustituciones. Se discute además el curso estereoquímico de esta reacción en términos de simetría orbital y la utilidad de tales consideraciones en relación a la estereoquimica de los cuatro isómeros del aloocimeno.
MECHANISMS OF PHOTOREDUCTIONS AND HYDROGENOLYSIS OF PYRIMIDINE NUCLEOSIDES AND THEIR PHOTODIMERS
Authors: WITKOP BERNHARD
Published: January 2008

Abstract— Photoreduction of uridine to dihydrouridine in the presence of sodium borohydride is shown to be specific for uridine in nucleic acids. This selective reaction provides a method for the production of dihydrouridine in tRNA and messenger RNA in order to investigate its physiological role. Though the photoreduction stops at the dihydrouridine stage, dihydrouridine undergoes selective hydrogenolysis (dark reaction) to ‐γ‐hydroxypropylurea; this reaction is used analytically to detect dihydrouridine in tRNA, and in sequence studies. Thymidine differs from uridine, as the photoreduction does not stop at the dihydrothymidine level, but there is a rapid hydrogenolysis and ring opening. The mechanism and stereochemistry of the hydrogenolysis of dihydrothymidine, photohydrate of thymidine, and photodimers of thymidine are described. The reaction seems capable of being developed into an analytical procedure to determine the photoproducts formed on u. v. irradiation of DN A.

Se ha demostrado que la fotorreducción de la uridina a dihidrouridina en presencia de borohidruro de sodioes especifica para uridina en ácidos nucleicos. Esta reacción selectiva provee un mecanismo para la incorporación de dihidrouridina en t‐RNA y “messenger RNA. La fotorreducción se detiene a nivel de la dihidrouridina, que luego mediante una hidrogenólisis forma γ‐hidroxipropil urea, esta reacción se usa para detectar dihidrouridina en t‐RNA. La timidina difiere de la uridina en que la fotorreducción no se detiene a nivel de la dihidrotimidina, sino que sufre una rápida hidrogenólisis con apertura del anillo. Se describen los mecanismos y la estereoquímica de la hidrogenólisis de la dihidrotimidina, fotohidrato de timidina y fotodimero de timidina. La reacción es desarrollada en un procedimiento analítico para determinar los fotoproductos formados en DNA irradiado con luz u.v.
Thermoacoustic tomography forward modeling with the spectral element method
Authors: Lim Kim Hwa , Lee Joon‐Ho , Liu Qing Huo
Published: January 2008

A thermoacoustic tomography (TAT) forward solver based on the spectral element method (SEM) with perfectly matched layer absorbing boundary condition has been developed. The TAT forward solver is intended to model acoustically inhomogeneous media with high accuracy in the frequency domain. The high‐order basis functions used in the SEM are Gauss‐Lobatto‐Legendre (GLL) polynomials. Due to the orthogonality of the GLL basis functions and GLL quadrature integration, the mass matrix is diagonal and the stiffness matrix is sparse. Thus, the proposed method greatly reduces the memory requirement and computational time in comparison with the conventional finite element method (FEM). Numerical results show that the high‐order SEM is able to achieve the same accuracy as the FEM but with a much smaller number of unknowns. Therefore, the TAT forward solver based on SEM is able to simulate a large‐scale and realistic TAT problem.
A system for intensity modulated dose plan verification based on an experimental pencil beam kernel obtained by deconvolution
Authors: Azcona Juan Diego , Burguete Javier
Published: January 2008

The number of intensity modulated radiation therapy (IMRT) procedures is continuously growing worldwide and it is necessary to develop tools for patient specific quality assurance (QA) that avoid using machine time that could be employed in treating additional patients. One way of achieving this goal is to perform a multileaf collimator quality assurance periodically in the linear accelerator and check the treatment planning system (TPS) calculation by employing an independent calculation system. Within the work frame of the pencil beam kernel approach, a new system was developed for obtaining an experimental kernel. This new technique is based on a deconvolution procedure using the Hankel transform. The resulting kernel is obtained in a way completely independent of those employed in commercial treatment planning systems, usually calculated by Monte Carlo simulations. Also provided are comparisons between calculated and measured doses with radiographic film, linear array of diodes, and ionization chamber. Measurements taken in polystyrene and water for clinical IMRT plans demonstrate that this method can calculate IMRT dose distributions, as well as treatment times, with great accuracy. Apart from other applications, it can be used as a double‐check algorithm for IMRT QA.
Experience‐driven dose‐volume histogram maps of NTCP risk as an aid for radiation treatment plan selection and optimization
Authors: Kupchak Connor , Battista Jerry , Van Dyk Jake
Published: January 2008

Commonly, the quality of treatment plans is judged by a dose‐volume histogram (DVH) in regards to satisfying a series of dose‐volume constraints. This paper presents a novel technique for mapping normal tissue complication probabilities (NTCP) onto regions of dose‐volume space with statistical considerations of risk. Mapping is done for DVHs specific to one treatment technique for one disease site. In this study, the method is illustrated for simplified intensity modulated arc therapy of the prostate, and the resulting NTCP values apply to complications in the rectum. The method consists of implementing a Monte Carlo algorithm that creates a large set of DVH curves by simulating random walks through dose‐volume space. The walks are guided by a base set of clinical DVHs. Grid points in the dose‐volume space have an associated NTCP spectrum for curves passing above right of the grid point of interest. After a DVH is simulated and the NTCP estimate calculated using the Lyman model, dose‐volume points located to the bottom left of the curve are scored with this NTCP value and contributed to the spectrum of each point. A NTCP tolerance value is then selected and the risk of violating this tolerance is identified by a gray‐scale map in regions of dose‐volume space. The generated maps distinguish technique‐specific, high‐risk regions, a feature which is advantageous over fixed single‐point dose‐volume constraints commonly used. The maps also provide a visualization tool to help select safe and robust treatment plans and open the possibility for improving the efficiency of biologically based plan optimization by focusing on the more critical sections of DVH curves.
Leaf‐sequencing for intensity‐modulated arc therapy using graph algorithms
Authors: Luan Shuang , Wang Chao , Cao Daliang , Chen Danny Z. , Shepard David M. , Yu Cedric X.
Published: January 2008

Intensity‐modulated arc therapy (IMAT) is a rotational IMRT technique. It uses a set of overlapping or nonoverlapping arcs to create a prescribed dose distribution. Despite its numerous advantages, IMAT has not gained widespread clinical applications. This is mainly due to the lack of an effective IMAT leaf‐sequencing algorithm that can convert the optimized intensity patterns for all beam directions into IMAT treatment arcs. To address this problem, we have developed an IMAT leaf‐sequencing algorithm and software using graph algorithms in computer science. The input to our leaf‐sequencing software includes (1) a set of (continuous) intensity patterns optimized by a treatment planning system at a sequence of equally spaced beam angles (typically 10° apart), (2) a maximum leaf motion constraint, and (3) the number of desired arcs, . The output is a set of treatment arcs that best approximates the set of optimized intensity patterns at all beam angles with guaranteed smooth delivery without violating the maximum leaf motion constraint. The new algorithm consists of the following key steps. First, the optimized intensity patterns are segmented into intensity profiles that are aligned with individual MLC leaf pairs. Then each intensity profile is segmented into MLC leaf openings using a ‐link shortest path algorithm. The leaf openings for all beam angles are subsequently connected together to form 1D IMAT arcs under the maximum leaf motion constraint using a shortest path algorithm. Finally, the 1D IMAT arcs are combined to form IMAT treatment arcs of MLC apertures. The performance of the implemented leaf‐sequencing software has been tested for four treatment sites (prostate, breast, head and neck, and lung). In all cases, our leaf‐sequencing algorithm produces efficient and highly conformal IMAT plans that rival their counterpart, the tomotherapy plans, and significantly improve the IMRT plans. Algorithm execution times ranging from a few seconds to are observed on a laptop computer equipped with a Pentium M processor.
Rarity of Males in Pea Aphids Results in Mutational Decay
Authors: Brisson Jennifer A. , Nuzhdin Sergey V.
Published: January 2008

When females can reproduce without males, do males become an evolutionarily weaker sex whose genes experience mutational decay? We addressed this hypothesis in aphids, whose reproduction alternates between parthenogenetic and sexual forms: Over the course of a year, there can be 10 to 20 generations of asexual females but only a single, if any, generation with males. We used microarray analyses to identify male-biased, asexual female‐biased, and neutral genes. Interspecific comparisons reveal accelerated evolution of male-biased genes, and intraspecific polymorphisms exhibit a significant excess of nonsynonymous coding variation in male-biased genes. We conclude that the ability of females to reproduce asexually without males reduces selection constraints on male-based genes, resulting in their mutational decay.
Helium and Neon Abundances and Compositions in Cometary Matter
Authors: Marty Bernard , Palma Russell L. , Pepin Robert O. , Zimmermann Laurent , Schlutter Dennis J. , Burnard Peter G. , Westphal Andrew J. , Snead Christopher J. , Bajt Saša , Becker Richard H. , Simones Jacob E.
Published: January 2008

Materials trapped and preserved in comets date from the earliest history of the solar system. Particles captured by the Stardust spacecraft from comet 81P/Wild 2 are indisputable cometary matter available for laboratory study. Here we report measurements of noble gases in Stardust material. Neon isotope ratios are within the range observed in “phase Q,” a ubiquitous, primitive organic carrier of noble gases in meteorites. Helium displays
3
He/
4
He ratios twice those in phase Q and in Jupiter's atmosphere. Abundances per gram are surprisingly large, suggesting implantation by ion irradiation. The gases are probably carried in high-temperature igneous grains similar to particles found in other Stardust studies. Collectively, the evidence points to gas acquisition in a hot, high ion-flux nebular environment close to the young Sun.
Small Circuits for Large Tasks: High-Speed Decision-Making in Archerfish
Authors: Schlegel Thomas , Schuster Stefan
Published: January 2008

The enormous progress made in functional magnetic resonance imaging technology allows us to watch our brains engage in complex cognitive and social tasks. However, our understanding of what actually is computed in the underlying cellular networks is hindered by the vast numbers of neurons involved. Here, we describe a vertebrate system, shaped for top speed, in which a complex and plastic decision is performed by surprisingly small circuitry that can be studied at cellular resolution.
Numerical Simulations Unravel the Cosmic Web
Authors: Faucher-Giguère Claude-André , Lidz Adam , Hernquist Lars
Published: January 2008

The universe is permeated by a network of filaments, sheets, and knots collectively forming a “cosmic web.” The discovery of the cosmic web, especially through its signature of absorption of light from distant sources by neutral hydrogen in the intervening intergalactic medium, exemplifies the interplay between theory and experiment that drives science and is one of the great examples in which numerical simulations have played a key and decisive role. We recount the milestones in our understanding of cosmic structure; summarize its impact on astronomy, cosmology, and physics; and look ahead by outlining the challenges faced as we prepare to probe the cosmic web at new wavelengths.
Comparison of the Premier Toxin A and B Assay and the TOX A/B II Assay for Diagnosis of
Clostridium difficile
Infection
Authors: Novak-Weekley Susan M. , Hollingsworth Michele H.
Published: January 2008

Clostridium difficile
causes nosocomial diarrhea and is responsible for complications such as pseudomembranous colitis, megacolon, and perforation. Using 442 stool specimens, we compared the sensitivities and specificities of the Premier toxin A and B (Meridian Bioscience, Inc.) and
C. difficile
TOX A/B II (TechLab, Inc., Blacksburg, VA) immunoassays in the Virology Department of the Kaiser Permanente Regional Reference Laboratories. The Premier toxin A and B assay demonstrated a higher sensitivity (97.44%) and a higher positive predictive value (79.17%) than the
C. difficile
TOX A/B II assay (87.18% and 75.56%, respectively), while assay specificities and negative predictive values were similar. We also performed experiments using serially diluted, purified toxin A and B antigens to understand the basis for assay differences. The two assays’ toxin A antibodies detected toxin A at comparable levels. Preliminary results indicated that the toxin B antibody in the Premier toxin A and B assay could detect toxin B at a concentration of 125 pg/100 μl, while the toxin B antibody in the
C. difficile
TOX A/B II assay could not detect toxin B below a concentration of 250 pg/100 μl. Therefore, the Premier toxin A and B assay provides greater sensitivity than the
C. difficile
TOX A/B II assay, perhaps due to a superior detection ability of its toxin B antibody.
Acupuncture Stimulation at Sanyinjiao: Effect on the Sodium Pertechnetate Bioavailability in Rats
Authors: de Souza Deise Elisabete , Senna-Fernandes Vasco , de Carvalho Brito Lavínia , de Souza Raphael Sancho Sisley , França Daisy , Manoel Cristiano Viana , de Almeida Marcela Ceciliano , Bernardo-Filho Mario
Published: January 2008

In clinical acupuncture, when acupuncture points are stimulated, several types of reflex responses can be evoked. Consequently, different categories of physiological responses are induced, which include changes in the activities of internal organs and tissues. The acupuncture point Sanyinjiao (SP6) has been used successfully to treat different human gastrointestinal conditions. The aim of this work was to investigate the effects of end-organ response induced by acupuncture point SP6 on the bioavailability of the radiopharmaceutical sodium pertechnetate ( Na 99 m TcO 4) in Wistar rats. Healthy rats were allocated into 2 groups, control-CG and treated-TG. TG was bilaterally stimulated at acupuncture point SP6 with stainless steel needles. Ocular plexus administration of Na 99 m TcO 4 (3.7MBq) was carried out 10 min after every needle insertion in all animals. Ten minutes later, the animals were killed, the organs were isolated, the radioactivity was determined in a well gamma counter, and the percentage of injected dose per gram of tissue (%ID/g) was determined for each organ. The %ID/g was significantly altered ( p < 0.05) in the small intestine of TG (0.56 ± 0.09) when compared to CG (0.82 ± 0.18). These results may suggest that this stimulation might induce physiological responses capable of altering the bioavailability of the radiopharmaceutical sodium pertechnetate. These findings aid in providing a better understanding of acupuncture and its effects on various organs and tissues.
ON AXIAL AND PLANE-MIRROR INHOMOGENEITIES IN THE WMAP3 COSMIC MICROWAVE BACKGROUND MAPS
Authors: GURZADYAN V. G. , STAROBINSKY A. A. , KASHIN A. L. , KHACHATRYAN H. G. , YEGORIAN G.
Published: January 2008

We study inhomogeneities in the distribution of the excursion sets in the Cosmic Microwave Background (CMB) temperature maps obtained by the three years survey of the Wilkinson Microwave Anisotropy Probe (WMAP). At temperature thresholds |T| = 90 μ K , the distributions of the excursion sets with over 200 pixels are concentrated in two regions, nearly at the antipodes, with galactic coordinates l = 94.7°, b = 34.4° and l = 279.8°, b = -29.2°. The centers of these two regions drift towards the equator when the temperature threshold is increased. The centers are located close to one of the vectors of ℓ = 3 multipole. The two patterns of the substructures in the distribution of the excursion sets are mirrored, with χ2 = 0.7–1.5. There is no obvious origin of this effect in the noise structure of WMAP, and there is no evidence for a dependence on the galactic cut. Would this effect be cosmological, it could be an indication of an anomalously large component of horizon-size density perturbations, independent of one of the spatial coordinates, and/or of a non-trivial slab-like spatial topology of the Universe.
Technical perspective
Authors: Patterson David A.
Published: January 2008

Internet services are already significant forces in searching, retail purchases, music downloads, and auctions. One vision of 21st century IT is that most users will be accessing such services over a descendant of the cell phone rather than running shrink-wrapped software on a descendant of the PC.
A simulation platform
Authors: Balakrichenan Sandoche , Bugnazet Thomas , Becker Monique
Published: January 2008

Electronic NUmber Mapping (ENUM)[1] System, a suite of protocols developed by IETF is one of the simplest approach which permits communicating from the telephony to the Internet Protocol (IP) world and vice versa in a seamless manner. Implementing ENUM is simple because it uses the existing Domain Name System (DNS) to store and serve the information linking PSTN telephone numbers to network addresses and services (email address, SIP phone number etc.). Explanation of how a telephone number is converted to a Fully Qualified Domain Name (FQDN) is shown in fig.1.
Immunity to Citrullinated Proteins in Rheumatoid Arthritis
Authors: Klareskog Lars , Rönnelid Johan , Lundberg Karin , Padyukov Leonid , Alfredsson Lars
Published: January 2008

Antibodies to citrullinated proteins (ACPA), i.e., to peptides posttranslationally modified by the conversion of arginine to citrulline, are specific serological markers for rheumatoid arthritis (RA). Studies on anticitrulline immunity, summarized in this review, demonstrate that the criterion-based syndrome RA should be subdivided into at least two distinct subsets (ACPA-positive and ACPA-negative disease). A new etiological model is proposed for ACPA-positive RA, built on MHC class II–dependent activation of adaptive immunity. Fundamentals of this model include the following: (a) ACPA antedate onset of arthritis; (b) ACPA may aggravate arthritis in rodents; (c) ACPA are triggered in the context of genes that confer susceptibility to RA (HLA-DRB1 SE) and by environmental agents triggering RA (smoking or bacterial stimuli); (d) ACPA may complex with citrullinated proteins present in target tissue as part of a multistep process for arthritis development. The model provides a new basis for molecular studies on the pathogenesis of ACPA-positive arthritis.
Differential localization and regulation of two aquaporin-1 homologs in the intestinal epithelia of the marine teleostSparus aurata
Authors: Raldúa Demetrio , Otero David , Fabra Mercedes , Cerdà Joan
Published: January 2008

Aquaporin (AQP)-mediated intestinal water absorption may play a major osmoregulatory role in euryhaline teleosts, although the molecular identity and anatomical distribution of AQPs in the fish gastrointestinal tract is poorly known. Here, we have investigated the functional properties and cellular localization in the intestine of two gilthead seabream ( Sparus aurata) homologs of mammalian aquaporin-1 (AQP1), named SaAqp1a and SaAqp1b. Heterologous expression in Xenopus laevis oocytes showed that SaAqp1a and SaAqp1b were water-selective channels. Real-time quantitative RT-PCR and Western blot using specific antisera indicated that abundance of SaAqp1a mRNA and protein was higher in duodenum and hindgut than in the rectum, whereas abundance of SaAqp1b was higher in rectum. In duodenum and hindgut, SaAqp1a localized at the apical brush border and lateral membrane of columnar enterocytes, whereas SaAqp1b was detected occasionally and at very low levels at the apical membrane. In the rectum, however, SaAqp1a was mainly accumulated in the cytoplasm of a subpopulation of enterocytes spread in groups over the surface of the epithelia, including the intervillus pockets, whereas SaAqp1b was detected exclusively at the apical brush border of all rectal enterocytes. Freshwater acclimation reduced the synthesis of SaAqp1a protein in all intestinal segments, but it only reduced SaAqp1b abundance in the rectum. These results show for the first time in teleosts a differential distribution and regulation of two functional AQP1 homologs in the intestinal epithelium, which suggest that they may play specialized functions during water movement across the intestine.
Cholinergic-induced Ca2+ signaling in interstitial cells of Cajal from the guinea pig bladder
Authors: Johnston Louise , Carson Chris , Lyons Alan D. , Davidson Ross A. , McCloskey Karen D.
Published: January 2008

Acetylcholine released from parasympathetic excitatory nerves activates contraction in detrusor smooth muscle. Immunohistochemical labeling of guinea pig detrusor with anti- c-Kit and anti-VAChT demonstrated a close structural relationship between interstitial cells of Cajal (ICC) and cholinergic nerves. The ability of guinea pig bladder detrusor ICC to respond to the acetylcholine analog, carbachol, was investigated in enzymatically dissociated cells, loaded with the Ca2+ indicator fluo 4AM. ICC fired Ca2+ transients in response to stimulation by carbachol (1/10 μM). Their pharmacology was consistent with carbachol-induced contractions in strips of detrusor which were inhibited by 4-DAMP (1 μM), an M3 receptor antagonist, but not by the M2 receptor antagonist methoctramine (1 μM). The source of Ca2+ underlying the carbachol transients in isolated ICC was investigated using agents to interfere with influx or release from intracellular stores. Nifedipine (1 μM) or Ni2+ (30–100 μM) to block Ca2+ channels or the removal of external Ca2+ reduced the amplitude of the carbachol transients. Application of ryanodine (30 μM) or tetracaine (100 μM) abolished the transients. The phospholipase C inhibitor, U-73122 (2.5 μM), significantly reduced the responses. 2-Aminoethoxydiethylborate (30 μM) caused a significant reduction and Xestospongin C (1 μM) was more effective, almost abolishing the responses. Intact in situ preparations of guinea pig bladder loaded with a Ca2+ indicator showed distinctively different patterns of spontaneous Ca2+ events in smooth muscle cells and ICC. Both cell types responded to carbachol by an increase in frequency of these events. In conclusion, guinea pig bladder detrusor ICC, both as isolated cells and within whole tissue preparations, respond to cholinergic stimulation by firing Ca2+ transients.
Estrogen Induces Repression of the Breast Cancer and Salivary Gland Expression Gene in an Estrogen Receptor α–Dependent Manner
Authors: Bretschneider Nancy , Brand Heike , Miller Nicola , Lowery Aoife J. , Kerin Michael J. , Gannon Frank , Denger Stefanie
Published: January 2008

The focus of this study is on the expression and regulation of the estrogen-regulated breast cancer and salivary gland expression (BASE) gene that may function as a breast cancer marker. In MCF7 cells, BASE is repressed by estrogen in an estrogen receptor α (ERα)-dependent manner. Promoter analysis of the BASE gene led to the identification of a 2-kb upstream enhancer that harbors binding sites for ERα and FoxA1. The recruitment of both ERα and FoxA1 to this region was shown by chromatin immunoprecipitation analysis. Furthermore, mutation studies and knockdown experiments show a clear separation between gene expression mediated by FoxA1 and ERα-dependent gene regulation. Additionally, we provide information on BASE expression in human breast tumor samples. [Cancer Res 2008;68(1):106–14]
Impact of E2F-1 Expression on Clinical Outcome of Gastric Adenocarcinoma Patients with Adjuvant Chemoradiation Therapy
Authors: Lee Jeeyun , Park Cheol Keun , Park Joon Oh , Lim Taekyu , Park Young Suk , Lim Ho Yeong , Lee Inkyoung , Sohn Tae Sung , Noh Jae Hyung , Heo Jin Seok , Kim Sung , Lim Do Hoon , Kim Kyoung-Mee , Kang Won Ki
Published: January 2008

Purpose: There are no reliable prognostic markers that identify gastric cancer patients who may benefit from adjuvant chemoradiation therapy. E2F-1 was shown to be associated with radiosensitivity and chemosensitivity in certain tumor types. Therefore, we analyzed expression and prognostic significance of E2F-1 along with thymidylate synthase (TS) in R0-resected gastric adenocarcinoma patients, who underwent adjuvant chemoradiation therapy with 5-fluorouracil (5-FU) and leucovorin.

Experimental Design: The chemosensitivity to 5-FU and radiosensitivity were tested in three E2F-1–overexpressed gastric cancer cell lines in vitro. The expressions of TS and E2F-1 were analyzed in 467 R0-resected primary gastric cancer patients, who received adjuvant chemoradiation therapy with 5-FU and leucovorin using tissue microarray.

Results: The E2F-1 immunopositivity rate was 22.2% (103 of 465 samples) with a cutoff value of 5% immunoreactivity, whereas the TS-positive expression occurred in 19.0% of the 463 tumors tested. Using stepwise Cox proportional hazards regression modeling, multivariate analyses showed that the E2F-1 immunopositivity predicted more favorable survival as compared with the E2F-1 immunonegativity with borderline statistical significance [P = 0.050, hazard ratio (HR) = 0.702, 95% confidence interval, 0.487, 1.013]. However, the E2F-1 immunopositivity did not retain its statistical significance at multivariate analysis for predicting disease-free survival (data not shown, P = 0.270), but stage was the only influential factor for disease-free survival in stages IB to IV (M0) patients (P < 0.001). TS immunopositivity did not influence survival (P = 0.459) or disease-free survival (P = 0.447).

Conclusion: E2F-1 is a potentially novel independent prognostic factor that may identify gastric cancer patients who will likely benefit from adjuvant chemoradiation therapy following curative resection.
Oral Silibinin Inhibits In vivo Human Bladder Tumor Xenograft Growth Involving Down-Regulation of Survivin
Authors: Singh Rana P. , Tyagi Alpna , Sharma Girish , Mohan Sarumathi , Agarwal Rajesh
Published: January 2008

Purpose: Chemoprevention is an upcoming approach to control bladder cancer, which is one of the commonly diagnosed malignancies showing recurrence rate of 70% or even higher. Recently, we observed the in vitro efficacy of silibinin, a flavanolignan, in human bladder transitional cell papilloma RT4 cells. Here, we investigated the antitumor efficacy and associated mechanisms of silibinin in RT4 tumor xenograft.

Experimental Design: RT4 tumor xenograft was implanted s.c. in athymic nude mice, and then animals were oral gavaged with silibinin at 100 and 200 mg/kg doses, 5 days/week for 12 weeks. Tumor growth, body weight, and diet consumption were recorded, and tumors were analyzed for proliferation, apoptosis, and angiogenesis biomarkers and molecular alterations by immunohistochemistry, immunoblot analysis, and ELISA. p53 small interfering RNA was used in cell culture to examine the role of p53 in survivin expression.

Results: Silibinin feeding inhibited tumor xenograft growth without any gross signs of toxicity. Silibinin decreased tumor volume by 51% to 58% (P ≤ 0.01) and tumor weight by 44% to 49% (P < 0.05). Silibinin moderately (P < 0.001) decreased cell proliferation and microvessel density and strongly (P < 0.001) increased apoptosis in tumors. Silibinin robustly decreased survivin protein expression and its nuclear localization, as well as tumor-secreted level in mouse plasma, but increased p53 and cleaved caspase-3 levels in tumors. Silibinin-caused decrease in survivin was independent of p53.

Conclusion: These findings identified in vivo antitumor efficacy of silibinin against human bladder tumor cells involving down-regulation of survivin and an increase in p53 expression together with enhanced apoptosis.
War, Peace, and American Politics
Authors: Power Jonathan
Published: January 2008

Zbigniew Brzezinski remains at 79 the same feisty, acerbic intellectual he has always been, giving little quarter to his opponents. Admired rather than loved, he was, as President Jimmy Carter's national security advisor, the antithesis of the careful, more rounded, secretary of state, Cyrus Vance. Indeed, during that period, he was seen as the voice that gradually dissuaded Carter of his own more pacific inner convictions. He was responsible for the confrontational tone of accusations against the Soviet Union's failings on the human rights front, while at the same time playing down the human rights abuses in friendly countries such as Iran and Pakistan. He was the prime White House voice for secretly arming the mujahidin to fight the Soviets in Afghanistan, even before the Red Army invaded. It was he who persuaded Carter to block Vance's instinct to complete what the Soviets wanted—a further freeze on nuclear arms and instead go for the more demanding course of arms reductions, which badly upset Moscow.

At the same time he was the only one in the foreign policy apparatus with a vision of where America should lead the world. He was the philosopher king of the White House. Thus, it was he who persuaded Carter that it was possible to bring peace to the Middle East and to expend an immense amount of energy in successfully reconciling Israel and Egypt. He saw more clearly than most the importance of the United Nations and encouraged Andrew Young in his remarkably creative and highly unusual ambassadorship to that body.

Today, he has a powerful advisory role in Barack Obama's presidential bid and has emerged as President George W Bush's most searing foreign policy critic.
A Comparison of Weekly Monitoring Methods of the Palmer Drought Index
Authors: Rhee Jinyoung , Carbone Gregory J.
Published: January 2008

A method for weekly monitoring of the Palmer Drought Index (PDI) by using four parallel month-long calculation chains in rotation (“ROLLING” method) was tested for the Kansas Northwest Climate Division and the South Carolina Southern Climate Division and compared to two other methods, a modified version of the Climate Prediction Center’s weekly Palmer Drought Index monitoring method with a modified set of coefficients (“WEEKLY” method) and the National Climatic Data Center’s (NCDC’s) projected monthly Palmer Drought Index method using long-term historical daily normal temperature and precipitation (“NORMALS” method). The results for the Kansas Northwest Climate Division and the South Carolina Southern Climate Division generally agreed. The weekly method produced drought severity values that differ most from standard monthly PDI values despite using a modified set of coefficients. The method recently adopted by NCDC successfully estimated Palmer Modified Drought Index (PMDI) values late in the month, but often presented a misleading trend early in the month. The method used in this paper produced PMDI and Z Index values that approximate those found using the standard monthly PMDI code. It also preserves approximately the same length of memory found in that code, provides a tool for progressive drought monitoring allowing users to assess current drought conditions, produces a weekly historical archive of the Palmer Drought Severity Index (PDSI) and Palmer Hydrological Drought Index (PHDI), and enables users to identify the onset of drought early and more clearly.
Automatic Prediction of High-Resolution Daily Rainfall Fields for Multiple Extents: The Potential of Operational Radar
Authors: Schuurmans J. M. , Bierkens M. F. P. , Pebesma E. J. , Uijlenhoet R.
Published: January 2008

This study investigates the added value of operational radar with respect to rain gauges in obtaining high-resolution daily rainfall fields as required in distributed hydrological modeling. To this end data from the Netherlands operational national rain gauge network (330 gauges nationwide) is combined with an experimental network (30 gauges within 225 km2). Based on 74 selected rainfall events (March–October 2004) the spatial variability of daily rainfall is investigated at three spatial extents: small (225 km2), medium (10 000 km2), and large (82 875 km2). From this analysis it is shown that semivariograms show no clear dependence on season. Predictions of point rainfall are performed for all three extents using three different geostatistical methods: (i) ordinary kriging (OK; rain gauge data only), (ii) kriging with external drift (KED), and (iii) ordinary collocated cokriging (OCCK), with the latter two using both rain gauge data and range-corrected daily radar composites—a standard operational radar product from the Royal Netherlands Meteorological Institute (KNMI). The focus here is on automatic prediction. For the small extent, rain gauge data alone perform better than radar, while for larger extents with lower gauge densities, radar performs overall better than rain gauge data alone (OK). Methods using both radar and rain gauge data (KED and OCCK) prove to be more accurate than using either rain gauge data alone (OK) or radar, in particular, for larger extents. The added value of radar is positively related to the correlation between radar and rain gauge data. Using a pooled semivariogram is almost as good as using event-based semivariograms, which is convenient if the prediction is to be automated. An interesting result is that the pooled semivariograms perform better in terms of estimating the prediction error (kriging variance) especially for the small and medium extent, where the number of data points to estimate semivariograms is small and event-based semivariograms are rather unstable.