bluuebunny/crossref_metadata_2025 huggingface dataset:
SEASONAL CHANGES IN THE PROXIMATE AND FATTY ACID COMPOSITION OF SOME NATURALLY GROWN FRESHWATER CHLOROPHYTES1
Authors: Moore J. W.
Published: August 2007

The protein content of the filamentous Cladophora glomerata (L.) Kz., Ulothrix zonata (Web, & Mohr) Kz. and Spirogyra sp., collected from natural populations for 1 year, averaged 8.0–12.4% of the total dry weight; whereas, the corresponding levels of lipid, cellulose and ash were 11.9–16.1%, 10.0–17.8% and 14.6–24.0%, respectively. Mean values for carbohydrates, estimated by difference, ranged from 32.8 to 56.0%. The colonial Scenedesmus dimorphus (Turp.) Kz. and the unicellular Cosmarium laeve Rab., on the other hand, contained more protein, lipid and carbohydrate (estimated by difference) averaging 13–15.0%, 22.5–25.9% and 415–46.8%, respectively, and less cellulose (7.5–9.8%) and ash (8.2–9.8%). A consistent pattern of seasonal variation in the proximate composition was not normally evident for any species, reflecting the influence of several environmental parameters on the algae. Cladophora contained the greatest amount of phospholipid averaging; 10% by weight of total lipid with the smallest quantity (5%) in Scenedesmus. The predominant phospholipid fatty acid in all species was C18:1 followed by C18:2, C18:3 and C16:1 in Cladophora, Ulothrix and Spirogyra, and C16:1, C18:2 and C16:0 in Scenedesmus and Cosmarium. Oleic (C18:1) and hexadecanoic (C16:1) acids were predominant in the neutral lipids of all the algae, followed by C16:0, C18:2 and C18:3. The concentration of the different fatty acids of each Species varied considerably during the year with the proportion of C16:0 and C16:1, usually rising and that of C18:1 failing during the colder months.
COBALT EFFECTS ON CELL DIVISION AND CALCIUM UPTAKE IN THE COCCOLITHOPHORIDCRICOSPHAERA CARTERAE(HAPTOPHYCEAE)1
Authors: Blankenship Mayme Lee , Wilbur Karl M.
Published: August 2007

Cobalt was found to produce effects on cell division, cell protein, volume, calcium uptake, and ultrastructure of the calcifying algaCricosphaera carterae(Braarud & Fager.) Braarud. The rate of cell division increased slightly as the added Co concentration of the medium was increased from 0–10 μM. At higher added Co concentrations, the rate of division decreased approximately linearly with concentration until division was blocked almost completely at 100 μM Co. Inhibition of division was reversible after 2 days in Co. Protein content was elevated in Co‐treated nondividing cells but the rate of protein synthesis was markedly reduced. Cell volume also increased progressively with Co concentration, and after 72 h in 200 μM Co, the volume was 3.2 times that in culture medium (0.09 μM Co). Co had a dual effect on calcification as indicated by the uptake of45Ca. After 48 h treatment, Ca uptake had increased 53% in 100 μM and decreased 40% in 200 μM Co as compared with cells in 0.09 μM Co. Ultrastructurally, Co caused enlargement of the cell vacuole and the appearance of membrane‐bound vacuoles containing electron dense bodies.
HALOGENATION IN THE RHODOPHYTA1,2 A REVIEW
Authors: Fenical William
Published: August 2007

The halogens—chlorine, bromine and iodine—play an important, role in the biochemical processes of marine red algae. Recent studies show that various species from at least 5 orders of the Rhodophyta possess the unique ability to synthesize organic halogen‐containing compounds which are derived from seawater components. A variety of substances have been reported, with various structures from simple aliphatic halo‐ketones and brominated phenols to more sophisticated mono‐, sesqui‐ and diterpenes. While the biological functions of these compounds are not clearly understood, they appear to provide environmental advantage, probably involving predator avoidance responses and microflora antibiosis.
THE GENETIC BASIS OF MALE POTENCY IN VOLVOX CARTERI F. NAGARIENSIS (CHLOROPHYCEAE)1,2
Authors: Meredith Ruby F. , Starr Richard C.
Published: August 2007

Sexual males of Volvox carteri Stein f. nagariensis Iyengar secrete a hormone which induces sexual rather than asexual development in the next generation. Male recombinants from the original strains isolated from Japan showed an increase in potency of up to 100 times that of the original male clone, with later descendants showing potencies ranging from 100 times to 1/1000 the potency of this male. Potency is defined as the extent to which the hormone produced in 1 ml of medium by one parental spheroid containing 16 male spheroids can be diluted and retain its capacity to induce sexual differentiation. This is recorded as the percent of female response in the tube of limiting dilution, asexual females of the normal female strain being used as assay inoculum in a 1 in 10 dilution series of samples of male fluid containing the sexual hormone. Investigation of the genetic basis for potency in this species included selection of high and low potency male clones and crossing with sib females or backcrossing with original female. Results of the various crosses are interpreted as multigenic system not linked with sex, with more than one genotypic class per dilution level and with more than one genotypic class per apparent phenotypic class. Possible genic interactions are described in their relevance to the biosynthesis of a glycoprotein molecule, the sexual hormone having been characterized as a glycoprotein by Starr and Jaenicke (18).
THE ULTRASTRUCTURE AND CYTOCHEMISTRY OF RESTING CELL FORMATION INAMPHORA COFFAEFORMIS(BACILLARIOPHYCEAE)1
Authors: Anderson O. Roger
Published: August 2007

The ultrastructure of logarithmic‐growing cells and of resting cells in laboratory cultures ofAmphora coffaeformis(Ag.) Kütz. isolated from deep ocean water was examined using electron and light microscopy. The acid Phosphatase activity, chlorophyll a and lipid content were assessed at weekly intervals of resting cell formation during cold‐dark treatment, simulating deep ocean water. Approximately 4 wk are required to complete resting cell formation. During the first week, the cytoplasm undergoes extensive transformation and lysosomal activity is observed. Large vacules decrease in size and many small ones develop, the mitochondria become fewer and one or more massive mitochondria appear possibly by fusion of smaller ones; the cytoplasm becomes densely granular. During the second and third week, the cytoplasm continues to contract, lipid bodies begin to develop and the plastid becomes densely stained. At the fourth week, the mature resting cell is formed containing one or more massive mitochondria, a well‐formed plastid, and granular cytoplasm containing occasional lipid droplets. There is no change in frustule morphology and the cytoplasm does not produce a protective layer. The variation in chemical constituents correlates with microscopic structure of the cells. The fine structure of cells during growth resumption when exposed to light at 25 c is presented. Previous reports of viable, chlorophyll‐containing cells at great depths in the ocean may be explained by the results reported in this paper.
LONG‐TERM MAINTENANCE OF FERTILE ALGAL CLONES: EXPERIENCE WITHPANDORINA(CHLOROPHYCEAE)1,2
Authors: Coleman Annette W.
Published: August 2007

There is a need for simple, inexpensive methods to maintain algal clones of constant genotype over long periods of time.Pandorinazygospores survive many environmental rigors which destroy the vegetative cells. The zygospores are the preferable from for storage of the alga and remain viable for at least 15 yr. storage procedures and germination techniques are described for zygospores of 2 species. These are compared with reports in the literature concerning other algal genera. General procedures for storage and maintenance of both vegetative cells and spores are proposed.
CELL DIVISION IN THE FILAMENTOUS PLEURASTRUM AND ITS COMPARISON WITH THE UNICELLULARPLATYMONAS(CHLOROPHYCEAE)1
Authors: Molnar Kathy E. , Stewart Kenneth D. , Mattox Karl R.
Published: August 2007

At prophase inPleurastrum,extranuclear spindle microtubules develop from the region of centrioles, which lie lateral to the nucleus midway between the future sites of the metaphase spindle poles. The microtubules then move laterally to overarch the nucleus and finally become incorporated into the spindle. The centrioles do not migrate and therefore lie in the same plane as the chromosomes at metaphase. At telophase, 2, more different systems of microtubules develop from the vicinity of the centrioles—a phycoplast and extensive arrays of microtubules that ensheath the daughter nuclei. Cell division in the filamentousPleurastrumis compared to that in the green flagellate,Platymonas.The similarities between cell division in the 2 algae are interpreted as evidence: (i) that rhizoplasts (which inPlatymonasresemble myofibrils) are somehow homologous to microtubules; and, (ii) that cell division inPleurastrumdiffers from cell division in other examined filamentous chlorophycean genera because Pleurastrum has an independent evolutionary origin from a monad withPlatymonas‐like characteristics.
BLOOMS OF SURF‐ZONE DIATOMS ALONG THE COAST OF THE OLYMPIC PENINSULA, WASHINGTON. VI. DAILY PERIODICITY PHENOMENA ASSOCIATED WITH CHAETOCEROS ARMATUM IN ITS NATURAL HABITAT1,2
Authors: Lewin Joyce , Rao V. N. R.
Published: August 2007

Microscope observations of chains of Chaetoceros T. armatum T. West, collected, from its natural habitat, at Copalis Beach, Washington, have been made. A regular daily periodicity in the occurrence of cell division stages and length of the chains was found on each occasion (November, February, April, May, August). During the night, short chains of 3 cells predominated. In early morning hours, average chain lengths increased due to cell elongation, and nuclear and protoplast division occurred. This correlated with the time of day when cell masses of C. armatum first appeared at the surface of the water. In the late afternoon, the new silica valves of the daughter protoplasts were formed. Formation of special bristle‐bearing end valves effected the separation of long chains into shorter chains composed predominantly of 3 cells. (Cultured material was used to verify some of these stages.) This correlated with the time of day when cell masses disappeared from the water surface and dispersed.
PIGMENT AND CYTOLOGICAL EVIDENCE FOR RECLASSIFICATION OF NANNOCHLORIS OCULATA AND MONALIANTUS SALINA IN THE EUSTIGMATOPHYCEAE1
Authors: Antia N. J. , Bisalputra T. , Cheng J. Y. , Kalley J. P.
Published: August 2007

Nannochloris oculata Droop and Monallantus salina Bourrelly produce similar chloroplast pigments and show alike ultrastructural features separating them from the Chlorophyceae and Xanthophyceae, respectively, and linking them to the Eustigmatophyceae. It is proposed that N. oculata should be removed from the chlorophyceaen genus Nannochloris and transferred to a new taxon of coccoid eustigmatophytes containing the closely related M. salina: nomenclatural revisions are required for both strains.
THE REQUIREMENT FOR SILICON IN SYNURA PETERSENII (CHRYSOPHYCEAE)1,2
Authors: Klaveness Dag , Guillard Robert R. L.
Published: August 2007

A silicon requirement for growth is demonstrated for an alga other than a diatom. Concentrations of less than 1 μM silicate greatly decreased the growth rate of Synura petersenii Korshikov and caused morphological changes. Half of maximum growth rate (μmax= 1.12 divisions/day) appeared at a concentration of only 0.23 μM silicate. Germanium dioxide inhibited, growth considerably; the degree of inhibition varying from none to almost 100% depending upon both Si and Ge concentrations. The amount of silicon deposited in the external scales of S. petersenii is comparable per unit area to that of diatoms. S. petersenii is able to deplete the medium of silicate to very low levels. The feasibility of batch culture techniques for this kind of work is discussed briefly.
COMPARATIVE ULTRASTRUCTURE OF THE VALVES OF SOME CYCLOTELLA SPECIES (BACILLARIOPHYCEAE)1
Authors: Lowe Rex L.
Published: August 2007

Cyclotella atomus Hust., C. meneghiniana Kütz., C. comta (Ehr.) Kütz., C. antiqua W. Sm., C. michiganiana Skv., C. ocellata Pant., C. glomerata Bachmann, C. pseudostelligera Hust., and C. stelligera (Cleve et Grun.) V. H., were selected for ultrastructure investigations on the basis of their ready availability. Specimens were examined employing both transmission and scanning electron microscopy. Strutted processes, labiate processes, spines and other special features were surveyed in all species. On the basis of these observations the species of Cyclotella observed seem to be in one of 3 morphological groups, the meneghiniana group, the comta group, and the stelligera group.
FLAGELLAR APPARATUS, EYESPOT AND BEHAVIOR OF MICROTHAMNION KUETZINGIANUM (CHLOROPHYCEAE) ZOOSPORES1,2,3
Authors: Watson Melvin William
Published: August 2007

The flagellar apparatus of Microthamnion kuet‐zingianum Naegeli differs from, that of Chlamydomonas reinhardtii Dangeard in that the zoospores can autonomously orient their basal bodies for different types of swimming behavior, including forward, and backward progression with, stationary intervals. Reorientation of the basal regions of the flagella and of the basal bodies were documented by cinefilms and by stroboscopic and electron micrographs. Even when the flagella. were sheared off, the remaining stubs (containing the basal bodies) were capable of being reoriented, by the organism. Thus the mechanism of basal body reorientation cannot reside in the 9 + 2 flagellar shaft. Rather, the reorienting process involves a shortening or lengthening of the distal fiber and of the plasma membrane region overlying an anterior papilla. In their helical and spiral motions, the zoospores trace complicated, but surprisingly regular curves. Such motion might result from the inherent 3‐dimensional structure and beat of the flagella.

The eyespot has an invariable, highly asymmetric location within the cell in direct proximity with a specific microtubular band (MTE), but nevertheless may occur in either the anterior or posterior region of the chloroplast. Further, multiple eyespots may occur along the same side of MTE. This observation is consistent with the discovery (in Fucus sperm) that microtubules serve to align individual eyespot granules in eyespot‐ontogeny. By this means the position of the eyespot within a cell could well be determined.
STEROLS OF PORPHYRIDIUM(RHODOPHYTA)1,2
Authors: Cargile Nancy L. , Edwards Henry N. , McChesney James D.
Published: August 2007

Species of the unicellular Porphyridium have been examined for their sterol content. Clones of 4 species maintained in axenic, chemically‐defined culture were analyzed—these included P. sordidum Geitler, P. purpureum (Bory) Ross, P. aerugineum Geitler and P. violaceum Kormnann(P. griseum Geitler was not available to use for examination). The major sterol was 22‐dehydrocholesterol in all except P. aerugineum in which there was a mixture of this sterol, cholesterol and higher sterols. Traces of C28 and C29 sterols were detected in most instances as well.
ELECTRON MICROSCOPE OBSERVATIONS OF TELOPHASE II IN THE FLORIDEOPHYCEAE1
Authors: Scott J. L. , Thomas J. P.
Published: August 2007

Tetrahedral tetrasporangia of several florideophycean red, algae were examined with the electron microscope for details of meiosis. Only telophase II nuclei are described since earlier stages were not, observed. Both divisions of meiosis are presumed to occur within the confines of the original tetrasporangial mother cell nuclear envelope. Four nuclei are then formed simultaneously. These observations essentially support Yamanouchi's description of telophase II inPolysiphonia flexicaulis(Harvey) Collins (asP. violacea)and suggest that meiosis in these algae could be basically similar to “uninuclear meiosis” in the fungiSaprolegniaandSaccharomyces.
A comprehensive study of chronic schizophrenic patients: II: Biological, neuropsychological, and clinical correlates of CT abnormality
Authors: Pandurangi A. K. , Dewan M. J. , Boucher M. , Levy B. , Ramachandran T. , Bartell K. , Bick P. A. , Phelps B. H. , Major L.
Published: August 2007

Abstract— There are numerous reports of lateral cerebral ventricle enlargement on computed tomography (CT) in schizophrenics, but the significance and its relationship to traditional notions of organicity remain unclear. Therefore we studied a subgroup of chronic schizophrenics who had lateral ventriculomegaly (and also cortical hyperden‐sity) on a battery of relevant biological, neuro‐psychological, and clinical parameters such as electroencephalogram (EEG), platelet monoamine oxidase (MAO) and serum dopamine‐beta‐hydroxylase (DBH) activity, the Halstead Reitan Neuropsychological Battery (HRB), premorbid personality adjustment, drug response, positive and negative symptoms, employment history, and family history. Our findings support the notion that there is an “organic” subgroup of schizophrenia that has 1) CT structural abnormalities such as lateral ventricle enlargement and cortical hyperdensity; and cerebral dysfunction or deficits as evidenced by 2) an increased incidence of abnormal EEGs and also 3) greater impairment on neuropsychological tests. The biochemical measures, platelet MAO and serum DBH activity, nor any of the clinical measures could differentiate between the subgroups. The implications of these findings for the subtyping of schizophrenia are discussed.
Effect of RCC on the Reliability of Adhesive Flip Chip Joints
Authors: Frisk Laura K. , Kokko Kati H.
Published: August 2007

A need for higher packaging density and functionality has increased the use of new packaging technologies, which has also caused demand for higher interconnect densities on printed circuit boards (PCBs). Sequential build-up (SBU) processes can be used to meet these demands. In the SBU process, additional dielectric and conductor layers are formed on a core board, which is typically made of FR-4. Microvias are formed on these layers to achieve an electrical connection between them and the core board. Resin-coated copper foil (RCC) is the most widely used dielectric layer in the SBU process. The effect of RCC on the reliability of flip chip joints with anisotropically conductive adhesive film (ACF) was studied. Two substrates were used. The difference between the substrates was RCC laminated on the other substrate. The reliability of the test samples was studied using a temperature cycling test and a constant humidity test. The reliability of the substrate with the RCC was found to be better in both tests. Failure mechanisms were studied after the tests, using optical and scanning electron microscopes. After the temperature cycling, several of the test samples made with two highest bonding pressures showed delamination, which has probably caused the failures. In addition, failures occurred during the changes in the test temperature. These were probably caused by warping of the flip chip package. No delamination was found in the test samples with the lowest pressure. The failures in these series were probably caused by relaxation of the adhesive matrix and by too low deformation of the conductive particles. Several cracks had formed on the FR-4 substrates without the RCC during the temperature cycling. In addition, air bubbles were found in the test samples with the FR-4 substrates without the RCC. Since RCC is a pure resin system, it has a high coefficient of thermal expansion, which may cause problems, especially when large components are attached to it. However, in this study, the RCC was found to increase the reliability of the flip chip joints made with ACF during both temperature cycling and constant humidity testing.
Viscoelastic Influence on Dynamic Properties of PCB Under Drop Impact
Authors: Liu Fang , Meng Guang , Zhao Mei
Published: August 2007

Dynamic properties of printed circuit board (PCB) assembly under drop impact are investigated when viscoelasticity of substrate materials is considered. The main materials of a PCB substrate are macromolecule resins, which are typical viscoelastic materials. From the viewpoint of viscoelasticity, the dynamics of PCBs under drop impact is analyzed based on mass-damping-spring, beam, and plate theories. It is demonstrated that the viscoelasticity of a PCB has distinct influences on the dynamic properties of PCBs under board-level drop impact. When there is an increase in the viscosity of substrate materials, the damping coefficients of PCBs would rise, its deflection and acceleration responses could diminish faster, and the maximum deflection of PCBs would become smaller. Meanwhile, with the same viscosity and drop impact conditions, a larger plate would produce a bigger deflection response. Therefore, drop impact reliability could be enhanced by choosing substrate material of larger viscoelasticity and reducing properly the size of PCBs. Dynamic analysis of PCBs under drop impact not only contributes to perfecting theoretical research, but also provides a reference for the choice of substrate materials and reliability design of PCBs when electronic products are devised.
Investigations of the Thermal Spreading Effects of Rectangular Conduction Plates and Vapor Chamber
Authors: Chen Yen-Shu , Chien Kuo-Hsiang , Wang Chi-Chuan , Hung Tzu-Chen , Ferng Yuh-Ming , Pei Bau-Shei
Published: August 2007

This study examines the spreading ability of rectangular plates numerically, analytically, and experimentally. The effect of aspect ratio, defined as an equivalent radius of a heater divided by that of a spreader plate, is investigated. The numerical results show a very good agreement with the analytical solutions. From the calculated results, the spreading resistance of the conduction plates with a small aspect ratio is higher than the one-dimensional conduction resistance. Calculated results also show that the spreading ability of a metal plate would be affected slightly by the external convective heat-transfer coefficient when the ratio of the longitudinal heat convection to the lateral heat spreading is less than 0.1. In addition to the numerical analysis, experimental comparisons between copper∕aluminum plates and a vapor chamber having the same thickness have been conducted. The experimental results show that the thermal resistance of the metal plates is independent of input power whereas that of the vapor chamber shows a noticeable drop with increased power. For the influence of concentrated heat source, the surface temperature distributions for the metal plates become concentrated with a reduced aspect ratio. However, the variations of the aspect ratio and the input power would yield minor effects to the surface temperature distribution of the vapor chamber. As compared with the conduction plates, the vapor chamber would offer a lower temperature rise and a more uniform temperature distribution. Thus, the vapor chamber provides a better choice as a heat spreader for concentrated heat sources.
Parametric and Optimal Design in Electronic Packaging Using DSC:
Computational, Geometrical, and Material Aspects
Authors: Whitenack Russell , Desai Chandra , Rassaian Mostafa
Published: August 2007

The disturbed state concept (DSC) with the hierarchical single surface (HISS) plasticity model have been proposed and validated previously for a wide range of problems in electronic packaging. In this paper, detailed analyses are performed with the DSC∕HISS model to study the effect of various factors, such as computational and geometrical aspects and material parameters, on the failure life of chip substrate systems. The results and the methodology can be used for parametric analyses and optimal design of problems in electronic packaging.
UAV Team Decision and Control Using Efficient Collaborative Estimation
Authors: Shima Tal , Rasmussen Steven J. , Chandler Phillip
Published: August 2007

A novel decision-estimation methodology for a team of agents cooperating under communication imperfections is presented. The scenario of interest is that of a group of uninhabited aerial vehicles (UAVs) cooperatively performing, under communication delays, multiple tasks on multiple ground targets. In the proposed architecture, each UAV in the group runs an identical centralized decision algorithm and multiple information filters in parallel on its own states, its teammates’ states, and its own states as viewed by its teammates. Under perfect information, the decision architecture allows implicit coordination. Under imperfect information, the estimation of team members’ states enables predicting their cost to prosecute new tasks. Thus, the group performance under communication imperfections can be improved. Two different algorithms are proposed for the estimation process. The first is communication efficient, in which asynchronous information updates are sent to the network by individual members based on the value of the information to the rest of the group. The second is computation efficient utilizing synchronous information updates. Taking into account that the plan and plant of each UAV are known to the group improves the overall estimation process. Utilizing the MULTIUAV2 simulation testbed, a Monte Carlo study is presented. The benefit of using the proposed algorithms is shown with regard to the target prosecution rate and the communication bandwidth required for cooperation.
Oxidative Carbonylation of Methanol to Dimethyl Carbonate by Chlorine-Free Homogeneous and Immobilized 2,2'-Bipyrimidine Modified Copper Catalyst
Authors: Csihony Szilárd , Mika László T. , Vlád Gábor , Barta Katalin , Mehnert Christian P. , Horváth István T.
Published: August 2007

A chlorine-free catalyst, prepared in situ from Cu(II) acetate and 2,2'-bipyrimidine, can be used for the oxidative carbonylation of methanol to dimethyl carbonate. In situ high pressure IR and NMR spectroscopic studies suggest the formation of [Cu(2,2'-bipyrimidine)(CO)- (OMe)] as one of the key intermediates. The catalytic performance of the 2,2'-bipyrimidine-modified Cu-catalyst is similar to the CuCl-based system. The chlorine free catalyst can be immobilized by using the copolymer of 5-vinyl-2,2'-bipyrimidine and styrene.
Gas-Phase Clustering of NO+ with H2S and H2O
Authors: Uhlár Milan , Černušák Ivan
Published: August 2007

The complex NO+·H2S, which is assumed to be an intermediate in acid rain formation, exhibits thermodynamic stability of ∆Hº300 = -76 kJ mol-1, or ∆Gº300 = -47 kJ mol-1. Its further transformation via H-transfer is associated with rather high barriers. One of the conceivable routes to lower the energy of the transition state is the action of additional solvent molecule(s) that can mediate proton transfer. We have studied several NO+·H2S structures with one or two additional water molecule(s) and have found stable structures (local minima), intermediates and saddle points for the three-body NO+·H2S·H2O and four-body NO+·H2S·(H2O)2 clusters. The hydrogen bonds network in the four-body cluster plays a crucial role in its conversion to thionitrous acid.
FIBERS ON A GRAPH WITH LOCAL LOAD SHARING
Authors: DIVAKARAN UMA , DUTTA AMIT
Published: August 2007

We study a random fiber bundle model with tips of the fibers placed on a graph having co-ordination number 3. These fibers follow local load sharing with uniformly distributed threshold strengths of the fibers. We have studied the critical behavior of the model numerically using a finite size scaling method and the mean field critical behavior is established. The avalanche size distribution is also found to exhibit a mean field nature in the asymptotic limit.
EXPERIMENTAL VALIDATION OF MOTOR SCHEMA-BASED CELLULAR AUTOMATON MODEL FOR PEDESTRIAN DYNAMICS
Authors: WENG WENGUO , YUAN HONGYONG , FAN WEICHENG , HASEMI YUJI
Published: August 2007

In this paper, experiments were carried out to validate the motor schema-based cellular automaton model for pedestrian dynamics presented by Weng et al. [Int. J. Mod. Phys. C17, 853 (2006)]. Unidirectional pedestrian flow with different walk velocities is studied by means of simulations and experiments. The lower walk velocity was provided by the young people with special equipment, which made them walk slowly, to imitate the elderly people. Travel time of each pedestrian from start line to goal line with different initial distribution patterns and obstacles in the way was measured to compare with simulation results. The comparison results indicate that the experimental observations can be well reproduced with the motor schema-based cellular automaton model. And the simulation results of the mean travel time agree well with the experimental data.
FAST COMMUNITY IDENTIFICATION BY HIERARCHICAL GROWTH
Authors: RODRIGUES F. A. , TRAVIESO G. , da F. COSTA L.
Published: August 2007

A new method for community identification is proposed which is founded on the analysis of successive neighborhoods, reached through hierarchical growth from a starting vertex, and on the definition of communities as a subgraph whose number of inner connections is larger than outer connections. In order to determine the precision and speed of the method, it is compared with one of the most popular community identification approaches, namely Girvan and Newman's algorithm. Although the hierarchical growth method is not as precise as Girvan and Newman's method, it is potentially faster than most community finding algorithms.
NUMERICAL SIMULATION OF THE FORMATION AND PROPAGATION OF STREAMER
Authors: SETTAOUTI A. , SETTAOUTI L.
Published: August 2007

There has been considerable interest in non-thermal discharges over the past decade due to the increased number of industrial applications. The properties of discharges in electronegative gases are most frequently used for technological applications. For the improvement of performance in these applications, it is necessary to understand discharge dynamics experimentally and numerically. In this paper, a Monte Carlo simulation is carried out in sulfur hexafluoride (SF6) in uniform electric fields. The streamer propagation, electron, positive and negative ion distributions and space charge fields are studied in detail as time increases.
FORECASTING SMOOTHED NON-STATIONARY TIME SERIES USING GENETIC ALGORITHMS
Authors: NOROUZZADEH P. , RAHMANI B. , NOROUZZADEH M. S.
Published: August 2007

We introduce kernel smoothing method to extract the global trend of a time series and remove short time scales variations and fluctuations from it. A multifractal detrended fluctuation analysis (MF-DFA) shows that the multifractality nature of TEPIX returns time series is due to both fatness of the probability density function of returns and long range correlations between them. MF-DFA results help us to understand how genetic algorithm and kernel smoothing methods act. Then we utilize a recently developed genetic algorithm for carrying out successful forecasts of the trend in financial time series and deriving a functional form of Tehran price index (TEPIX) that best approximates the time variability of it. The final model is mainly dominated by a linear relationship with the most recent past value, while contributions from nonlinear terms to the total forecasting performance are rather small.
HITCHIN SYSTEMS ON SINGULAR CURVES II: GLUING SUBSCHEMES
Authors: CHERVOV A. , TALALAEV D.
Published: August 2007

In this paper we continue our studies of Hitchin systems on singular curves (started in [1]). We consider a rather general class of curves which can be obtained from the projective line by gluing two subschemes together (i.e. their affine part is: Spec {f ∈ ℂ[z] : f(A(∊)) = f(B(∊)); ∊N = 0}, where A(∊), B(∊) are arbitrary polynomials). The most simple examples are the generalized cusp curves which are projectivizations of Spec {f ∈ ℂ[z] : f′(0) = f″(0) = ⋯ fN-1(0) = 0}. We describe the geometry of such curves; in particular we calculate their genus (for some curves the calculation appears to be related with the iteration of polynomials A(∊), B(∊) defining the subschemes). We obtain the explicit description of moduli space of vector bundles, the dualizing sheaf, Higgs field and other ingredients of the Hitchin integrable systems; these results may deserve the independent interest. We prove the integrability of Hitchin systems on such curves. To do this we develop r-matrix formalism for the functions on the truncated loop group GLn(ℂ[z]), zN = 0. We also show how to obtain the Hitchin integrable systems on such curves as hamiltonian reduction from the more simple system on some finite-dimensional space.
Selective PPARδ agonist treatment increases skeletal muscle lipid metabolism without altering mitochondrial energy coupling: an in vivo magnetic resonance spectroscopy study
Authors: Jucker Beat M. , Yang Dewen , Casey Warren M. , Olzinski Alan R. , Williams Carolyn , Lenhard Stephen C. , Legos Jeffrey J. , Hawk C. Terrance , Sarkar Susanta K. , Newsholme Stephen J.
Published: August 2007

Peroxisome proliferator-activated receptor-δ (PPARδ) activation results in upregulation of genes associated with skeletal muscle fatty acid oxidation and mitochondrial uncoupling. However, direct, noninvasive assessment of lipid metabolism and mitochondrial energy coupling in skeletal muscle following PPARδ stimulation has not been examined. Therefore, in this study we examined the response of a selective PPARδ agonist (GW610742X at 5 or 100 mg·kg−1·day−1 for 8 days) on skeletal-muscle lipid metabolism and mitochondrial coupling efficiency in rats by using in vivo magnetic resonance spectroscopy (MRS). There was a decrease in the intramyocellular lipid-to-total creatine ratio as assessed by in vivo 1H-MRS in soleus and tibialis anterior muscles by day 7 (reduced by 49 and 46%, respectively; P < 0.01) at the high dose. Following the 1H-MRS experiment ( day 8), [1-13C]glucose was administered to conscious rats to assess metabolism in the soleus muscle. The relative fat-vs.-carbohydrate oxidation rate increased in a dose-dependent manner (increased by 52 and 93% in the 5 and 100 mg·kg−1·day−1 groups, respectively; P < 0.05). In separate experiments where mitochondrial coupling was assessed in vivo ( day 7), 31P-MRS was used to measure hindlimb ATP synthesis and 13C-MRS was used to measure the hindlimb tricarboxylic acid cycle flux (Vtca). There was no alteration, at either dose, in mitochondrial coupling efficiency measured as the ratio of unidirectional ATP synthesis flux to Vtca. Soleus muscle GLUT4 expression was decreased by twofold, whereas pyruvate dehydrogenase kinase 4, carnitine palmitoyl transferase 1a, and uncoupling protein 2 and 3 expression was increased by two- to threefold at the high dose ( P < 0.05). In summary, these are the first noninvasive measurements illustrating a selective PPARδ-mediated decrease in muscle lipid content that was consistent with a shift in metabolic substrate utilization from carbohydrate to lipid. However, the mitochondrial-energy coupling efficiency was not altered in the presence of increased uncoupling protein expression.
Glyceroneogenesis and the supply of glycerol-3-phosphate for glyceride-glycerol synthesis in liver slices of fasted and diabetic rats
Authors: Martins-Santos Maria Emilia Soares , Chaves Valéria Ernestânia , Frasson Danúbia , Boschini Renata Polessi , Garófalo Maria Antonieta Rissato , Kettelhut Isis do Carmo , Migliorini Renato Hélios
Published: August 2007

The pathways of glycerol-3-phosphate (G3P) generation for glyceride synthesis were examined in precision-cut liver slices of fasted and diabetic rats. The incorporation of 5 mM [U-14C]glucose into glyceride-glycerol, used to evaluate G3P generation via glycolysis, was reduced by ∼26–36% in liver slices of fasted and diabetic rats. The glycolytic flux was reduced by ∼60% in both groups. The incorporation of 1.0 mM [2-14C]pyruvate into glyceride-glycerol (glyceroneogenesis) increased ∼50% and ∼36% in slices of fasted and diabetic rats, respectively, which also showed a two-fold increase in the activity phospho enolpyruvate carboxykinase. The increased incorporation of 1.0 mM [2-14C]pyruvate into glyceride-glycerol by slices of fasted rats was not affected by the addition of 5 mM glucose to the incubation medium. The activity of glycerokinase and the incorporation of 1 mM [U-14C]glycerol into glyceride-glycerol, evaluators of G3P formation by direct glycerol phosphorylation, did not differ significantly from controls in slices of the two experimental groups. Rates of incorporation of 1 mM [2-14C]pyruvate and [U-14C]glycerol into glucose of incubation medium (gluconeogenesis) were ∼140 and ∼20% higher in fasted and diabetic slices than in control slices. It could be estimated that glyceroneogenesis by liver slices of fasted rats contributed with ∼20% of G3P generated for glyceride-glycerol synthesis, the glycolytic pathway with ∼5%, and direct phosphorylation of glycerol by glycerokinase with ∼75%. Pyruvate contributed with 54% and glycerol with 46% of gluconeogenesis. The present data indicate that glyceroneogenesis has a significant participation in the generation of G3P needed for the increased glyceride-glycerol synthesis in liver during fasting and diabetes.
Inhalation of a pulmonary irritant modulates activity of lumbosacral spinal neurons receiving colonic input in rats
Authors: Qin Chao , Foreman Robert D. , Farber Jay P.
Published: August 2007

The purpose of the present study was to determine whether an intraspinal nociceptive pathway from the lungs modulated activity of spinal neurons that also received afferent input from the colon. Extracellular potentials of single lumbosacral (L6–S2) spinal neurons were recorded in pentobarbital-anesthetized, paralyzed, and ventilated male rats. The lower airways and lungs were irritated by injecting ammonia vapor over a 30% NH4OH solution into the inspiratory line of the ventilator (0.5 ml, 20 s). Graded colorectal distension (CRD; 20–60 mmHg, 20 s) was produced by air inflation of a balloon. Inhaled ammonia (IA) altered activity of 31/51 (61%) lumbosacral spinal neurons responding to noxious CRD (60 mmHg, 20 s). In contrast, IA changed activity of 3/30 (10%) spinal neurons with somatic fields that did not respond to colorectal inputs. IA decreased activity of 16/31 (52%) spinal neurons and increased activity of the other 15 neurons with colorectal input. Multiple patterns of viscerovisceral convergent spinal neurons with excitatory and inhibitory responses to CRD and IA were observed; 87% (27/31) of the viscerovisceral convergent neurons also responded to innocuous and/or noxious stimuli of somatic fields. Bilateral cervical vagotomy abolished responses to IA in 2/8 tested neurons, indicating that the remaining 6 neurons had input originating from sympathetic afferent fibers. Rostral C1 spinal transection did not abolish inhibitory responses to IA in 4/4 neurons, but L2 transection eliminated inhibitory responses to IA in 3/3 neurons. These results indicated that irritation of the lower airways modulated activity of lumbosacral spinal neurons with colorectal input. It might contribute to intraspinal cross talk between the colon and lungs.
Stone Composition: Where Do We Stand?
Authors: Saita A. , Bonaccorsi A. , Motta M.
Published: August 2007

Kidney stones are a common disorder of the urinary tract. Nephrolithiasis is a morbid and expensive disease. The prevalence and incidence are estimated at 5–10% and 100–300/100,000/year, respectively. Relapses occur in 50–70% of all cases. For these reasons, prevention of stone formation is of great importance. Knowing the composition of the calculus is thus fundamental for a more complete evaluation of the metabolic study. The nature of the calculus in fact helps the physician to find a convenient metaphylaxis consisting of both sanitary and therapeutic measures. Study of the composition of urinary stones remains one of the most interesting aspects of the lithiasic pathology today. Presently crystallographic examination constitutes one of the most precise and less expensive methodologies to identify the nature of the concretion. This method also allows the urologist to catalogue the typology of the lithiasis during endos-copy.
Ocular Photodynamic Therapy – Standard Applications and New Indications (Part 2)
Authors: Mennel Stefan , Barbazetto Irene , Meyer Carsten H. , Peter Silvia , Stur Michael
Published: August 2007

Photodynamic therapy (PDT) has become a well-established treatment for vascular forms of age-related macular degeneration (AMD). The implementation of evidence-based medicine principles into the treatment regimen of AMD seems to be immensly important, since AMD continues to be the most frequent cause of blindness among patients older than 65 years in industrialized countries. Numerous randomized prospective studies demonstrated high levels of evidence for the efficacy of various treatment approaches such as laser photocoagulation, PDT, subretinal surgery or novel anti-angiogenic drugs [Arch Ophthalmol 2006;124:597–599]. The high evidence shown by these studies supported the rationale to use PDT also in additional, less frequent, vasoproliferative diseases. Although these ‘case series’ and ‘individual case control studies’ have a low level of evidence, they give us important information for treatment decisions in these rare conditions. The goal of this survey is to review the current literature regarding PDT in vasoproliferative and exudative ocular diseases outside AMD. Many studies modified the treatment parameters of PDT to address the specific pathology of the underlying disease. Table 1 summarizes the diseases and treatment parameters that are described in this part 2, the entire table of this review is included in part 1 (www.karger.com/doi/10.1159/ 000101922).
Antiadenoviral Effect of the α5β1 Integrin Receptor Ligand, GRGDSP Peptide, in Serotypes That Cause Acute Keratoconjunctivitis
Authors: Uchio Eiichi , Kimura Ryoji , Huang Yuh-Huey , Fuchigami Aya , Kadonosono Kazuaki , Hayashi Akio , Ishiko Hiroaki , Aoki Koki , Ohno Shigeaki
Published: August 2007

Background/Aims: In adenoviral conjunctivitis, the infection process starts by the attachment of adenoviral fibers to conjunctival epithelial cells that contain the receptor for the adenovirus. The α5β1 integrin receptor ligand, GRGDSP peptide, contains the arginine-glycine-aspartate-binding motif which is common to the Coxsackie adenovirus receptor and integrins that are known to be adenoviral receptors. We evaluated the antiadenoviral effect of an expected adenoviral receptor inhibitor, GRGDSP peptide,in vitro. Methods: Adenovirus types 3, 4, 8, 19 and 37 were used. After calculating the 50% cytotoxic concentration of GRGDSP peptide, the adenovirus was cultivated with the agent for 7 days under serial dilution. Adenoviral DNA was qualitatively measured by real-time PCR. Results: GRGDSP peptide showed an inhibitory effect against adenoviral proliferation in all serotypes except type 4 in a dose-dependent manner. Conclusion: This result suggests that the α5β1 integrin receptor ligand, GRGDSP peptide, has antiadenoviral activity in vitro, and the possibility of being used for local treatment of epidemic keratoconjunctivitis.
Argatroban Therapy in Patients with Coronary Artery Disease and Heparin-Induced Thrombocytopenia
Authors: Jang Ik-Kyung , Hursting Marcie J. , McCollum David
Published: August 2007

The efficacy of the direct thrombin inhibitor argatroban was investigated in patients who developed heparin-induced thrombocytopenia following heparin therapy for coronary artery disease. The outcome of 121 patients treated with argatroban was compared with that of 26 patients in a historical control (i.e. patients who did not receive direct thrombin inhibition therapy). Argatroban, compared with controls, significantly reduced the 37-day composite of death, amputation or new thrombosis (30 versus 50%, p = 0.043), primarily driven by a significant decrease in new thrombosis (10 versus 31%, p = 0.01), and led to less bleeding (4 versus 15%, p = 0.046). Therefore, in patients with coronary artery disease who develop heparin-induced thrombocytopenia, argatroban provides safe, effective anticoagulation.
Severe Pregnancy-Induced Deterioration of Truncal Valve Regurgitation in an Adolescent Patient with Repaired Truncus Arteriosus
Authors: Hoendermis Elke S. , Drenthen Willem , Sollie Krystyna M. , Berger Rolf M.F.
Published: August 2007

Truncus arteriosus, a rare and complex congenital heart disease, is hallmarked by a single great vessel (truncus) that arises over a large ventricular septal defect and provides both the pulmonary and systemic circulation. Pregnancy reports after repair for truncus arteriosus are scarce. Therefore, the maternal and offspring outcomes are unknown. We report the outcome of a pregnancy in an 18-year-old woman with repaired truncus arteriosus. Despite severe and symptomatic deterioration of truncal valve regurgitation, she successfully delivered a healthy child, and the valve function recovered within 2 weeks postpartum.
Downregulated Cardiac Annexin VI mRNA and Protein Levels in Chronically Fibrillating Human Atria
Authors: Ueng Kwo-Chang , Lin Chung-Sheng , Yeh Hung-I , Wu Yi-Liang , Liu Rosa Huang , Tsai Chin-Feng , Tsai Tsung-Po , Chen Shih-Ann
Published: August 2007

Objectives: We compared the expression and distribution of atrial annexin VI between patients with atrial fibrillation (AF) or sinus rhythm (SR). Methods: Atrial appendages were obtained during cardiac surgery from 20 patients with chronic AF and 34 matched controls in SR. The expression and distribution of annexin VI were analyzed using semiquantitative RT-PCR, Western blotting and immunoconfocal microscopy. Results: In the AF group, compared to SR, the mRNA was reduced to <35% and the protein to <50% in amount (for each atrium, all p < 0.01). Immunoconfocal microscopy confirmed the downregulation of annexin VI protein in AF and demonstrated the colocalization of annexin VI with both Na+/Ca2+ exchangers and L-type Ca2+ channels in the sarcolemma, but not with ryanodine receptors in the sarcoplasmic reticulum. Conclusions: Atrial annexin VI, spatially colocalized with both Na+/Ca2+ exchangers and L-type Ca2+ channels in the myocyte membrane, is downregulated during chronic AF.