bluuebunny/crossref_metadata_2025 huggingface dataset:
High risk occupations for non-Hodgkin’s lymphoma in New Zealand: case–control study
Authors: Mannetje A ’t , Dryson E , Walls C , McLean D , McKenzie F , Maule M , Cheng S , Cunningham C , Kromhout H , Boffetta P , Blair A , Pearce N
Published: November 2007

Objectives:

Previous studies into occupational risk factors for non-Hodgkin’s lymphoma (NHL) in New Zealand have indicated that farmers and meat workers are at increased risk for these neoplasms. A new nationwide case–control study was conducted to assess whether previously observed associations persist and to identify other occupations that may contribute to the risk of NHL in the New Zealand population.

Methods:

A total of 291 incident cases of NHL (age 25–70 years) notified to the New Zealand Cancer Registry during 2003 and 2004, and 471 population controls, were interviewed face-to-face. The questionnaire collected demographic information and a full occupational history. The relative risk for NHL associated with ever being employed in particular occupations and industries was calculated by unconditional logistic regression adjusting for age, sex, smoking, ethnicity and socioeconomic status. Estimates were subsequently semi-Bayes adjusted to account for the large number of occupations and industries being considered.

Results:

An elevated NHL risk was observed for field crop and vegetable growers (OR 2.74, 95% CI 1.04 to 7.25) and horticulture and fruit growing (OR 2.28, 95% CI 1.37 to 3.79), particularly for women (OR 3.44, 95% CI 0.62 to 18.9; OR 3.15, 95% CI 1.50 to 6.61). Sheep and dairy farming was not associated with an increased risk of NHL. Meat processors had an elevated risk (OR 1.97, 95% CI 0.97 to 3.97), as did heavy truck drivers (OR 1.98, 95% CI 0.92 to 4.24), workers employed in metal product manufacturing (OR 1.92, 95% CI 1.12 to 3.28) and cleaners (OR 2.11, 95% CI 1.21 to 3.65). After semi-Bayes adjustment the elevated risks for horticulture and fruit growing, metal product manufacturing and cleaners remained statistically significant, representing the most robust findings of this study.

Conclusions:

This study has confirmed that crop farmers and meat workers remain high risk occupations for NHL in New Zealand, and has identified several other occupations and industries of high NHL risk that merit further study.
Ultrastructure of the interaction between Pyrenophora teres and a susceptible barley host
Authors: Caeseele L. Van , Grumbles J.
Published: November 2007

Host–-parasite interfaces in leaves of a susceptible barley cultivar inoculated with Pyrenophora teres were studied using light and electron microscopy. Entry into the host rarely occurred through stomata, normal entry was by penetration into epidermal cells. Disruption of cell contents was evident in all initial penetration sites. After penetrating the epidermal cell, the fungus produced a large infection vesicle which gave rise to one or sometimes two intracellular hyphae. Hyphae spread down through the leaf tissue intracellularly for one or two cell layers and intercellularly thereafter. A septum, coincident with the external epidermal cell wall, was present in the infection peg located between the appressorium and the vesicle. Prior to leaving the epidermal cell, hyphae swelled to produce appressorium-like structures. These hyphae were sometimes septate at the point of exit. At sites where the infection had penetrated only four or five cell layers deep, the cellular contents of the mesophyll cells were relatively unaffected despite the presence of intercellular hyphae. However, when hyphae occasionally penetrated a host cell, gross disruption of their contents was apparent.
Studies in the Alismataceae. VII. Disruption of phyllotactic and organogenetic patterns in pseudostolons of Echinodorus tenellus by means of growth-active substances
Authors: Charlton W. A.
Published: November 2007

Treatment of plants of Echinodorus tenellus with gibberellic acid (GA) and kinetin (K) resulted in major but erratic changes in the developmental pattern of the pseudostolons (sterilized inflorescences). Both GA and K can cause the pseudostolon meristem to become vegetative and can cause the production of additional large vegetative buds. Where additional buds are present, phyllotaxis can be modified, particularly in relation to the maintenance or reversal of genetic spiral. K can induce disturbances in the arrangement of bracts by modifying or breaking down the normal pseudowhorled arrangement. The pseudostolon of E. tenellus is visualized as a developmental system which is basically very stable, though made up of several elements of pattern which may be affected independently by experimental treatment.
Aberrations in flower development in Silene
Authors: Lyndon R. F.
Published: November 2007

The occurrence of aberrant numbers of floral parts in Silene coeli-rosa was most frequent at high and low temperatures but was not obviously correlated with effectiveness of floral induction or with the growth rate of the flower. The stamens were more often aberrant than the other floral whorls. Aberrations seemed to occur independently in the different floral whorls, except in the case of the sepals and petals, since almost half the plants with aberrant numbers of sepals showed the same aberration in the petals. The findings are considered in relation to normal flower development.
Growth of barley pollen tubes in vivo. I. Ultrastructural aspects of early tube growth in the stigmatic hair
Authors: Cass David D. , Peteya Daniel J.
Published: November 2007

Barley styles were examined with transmission electron microscopy (TEM) and scanning electron microscopy (SEM) before and after pollination. Pollen tube penetration of a stigmatic hair may follow initial missing of the hair and (or) a period of growth on the hair surface. Changes in hair cell walls occur at penetration sites. Absence of demonstrable reserve carbohydrate in hair cells and styles and its abundance in pollen tubes suggest that early tube growth is largely dependent on endogenous substrates relative to its carbohydrate requirement. The pollen tube wall has an inner, somewhat reticular region and an outer, multilayered fibrillar region. Membrane-bound pollen tube vesicles containing reticular material fuse with the pollen tube membrane, contributing to development of the pollen tube wall. Vesicles and tube wall are stained by Ruthenium Red; this staining is compared with results of periodic acid–silver proteinate treatment. Two types of tube growth anomalies are reported. In the first, a tube may grow out of a hair and discharge its cytoplasm onto the hair surface through an aperture. Discharged, naked tube cytoplasm often remains appressed to hair surfaces. In the second, a tube may grow into a hair cell and discharge its contents therein through an apparently similar aperture. Vegetative nuclei appear unaltered during early pollen tube growth, but there are minor structural alterations in sperms and vegetative cell cytoplasm.
Bud development in Larix occidentalis. I. Growth and development of vegetative long shoot and vegetative short shoot buds
Authors: Owens John N. , Molder Marje
Published: November 2007

Vegetative terminal long shoot buds (TLSB) and short shoot buds (SSB) were studied throughout the annual growth cycle in several trees over several years. TLSB were not totally preformed. The dormant TLSB consisted of bud scales enclosing some basal leaves and both were borne on a broad receptacle. Centripetal to the basal leaves, a series of axial leaf primordia was borne on the flanks of the apex. After dormancy a second series of axial leaves was initiated above those initiated before dormancy. Basal and both series of axial leaves elongated during shoot elongation as the terminal apex again initiated axial leaves, bud scales, and then basal leaves. After shoot elongation the first series of axial leaves was initiated before the TLSB became dormant in October. No dimorphism occurred between predormancy and postdormancy axial leaves or axial and basal leaves. Axilliary buds were initiated in the TLSB about the time of flushing. All leaves did not bear axillary buds. All axillary buds rapidly initiated a series of bud scales and then entered a slower phase of bud-scale initiation and rapid apical enlargement. Leaf primordia then were initiated at the base of the apex and borne on the broad receptacle. Apices then differentiated into axillary long shoot buds (ALSB) or SSB. ALSB developed similarly to TLSB, whereas axillary SSB initiated leaf primordia at the base of the apex and all but the last primordia to be initiated were borne on the broad receptacle. Axillary SSB were preformed but ALSB were not completely preformed and both became dormant in mid-October. The apex of a short shoot lived for up to 8 to 10 years. In each successive year it passed through phases of bud-scale initiation and leaf initiation to form a dormant preformed SSB which flushed after overwintering. Annual short shoot elongation was about 1 mm. The LSB and SSB apices varied in shape and size during the year but apical zonation was similar in all apices. Larix vegetative bud development is compared with that found in other gymnosperms.
The effects of date of emergence and emergence order on seedling survival rates in Rumex crispus and R. obtusifolius
Authors: Weaver Susan E. , Cavers Paul B.
Published: November 2007

Populations of the colonizing weeds Rumex crispus L. and R. obtusifolius L. were initiated from seed following disturbance on three occasions between May and September 1976. Three distinct cohorts were followed within each population. Cohorts which had the same order of emergence within a population but different dates of emergence had similar mortality rates. On the other hand, when cohorts of different emergence order and similar emergence dates were compared, those cohorts which emerged first had the lower mortality rates. For both species, the population arising latest in the season had the lowest percentage emergence but the greatest percentage survival of emerged plants to the time of flowering. These populations also had the best reproductive performance. The latest emerging population of R. crispus was the only one to produce as many seeds as had originally been sown, despite the fact that less than 10% of the emerged seedlings survived the winter and less than 1% of the seed pool gave rise to flowering plants. These results suggest that the timing of land management practices such as cultivation can have a profound effect on the success of weed populations.
Glutamine synthetase and nitrate assimilation in sorghum (Sorghum vulgare) leaves
Authors: Scott D. Barry , Neyra Carlos A.
Published: November 2007

The patterns of nitrate reduction, nitrate accumulation, and glutamine synthetase activity as a function of leaf development were studied in glasshouse-grown sorghum (Sorghum vulgare L. var. Dourado) seedlings. Leaf nitrate reductase activity increased during early leaf development and reached a maximum at full leaf expansion which was followed by a decline with leaf maturation. Leaf nitrate content closely paralleled the pattern of nitrate reductase activity for each individual leaf along the canopy. Glutamine synthetase activity increased during early leaf development but then remained constant until senescence. Etiolated leaves from nitrate-grown plants had minimal levels of nitrate reductase activity which increased markedly upon illumination. Glutamine synthetase activity was already high in those leaves and increased only slightly during greening. Crude preparations of glutamine synthetase were insensitive to cyanide and both the biosynthetic and transferase assays were enhanced by cysteine. The relatively high activities of glutamine synthetase throughout leaf development and greening indicate that this enzyme does not limit the assimilation of nitrate into amino acids and plays a role in the assimilation of ammonia from sources other than NO3− reduction.
Rapid influences of water stress on photosynthesis and translocation in Phaseolus vulgaris
Authors: Hoddinott John , Ehret D. L. , Gorham Paul R.
Published: November 2007

A steady-state 14C labelling system is used to simultaneously measure rates of photosynthesis and translocation before and after the onset of an osmotic shock to the base of rooted or rootless Phaseolus vulgaris plants. In all experiments, the photosynthetic rate declines soon after the onset of a shock owing to rapid stomatal closure. The translocation rate, following a brief transient change, remains almost constant for several hours, indicating less sensitivity to osmotic shock than is shown by the photosynthetic rate. The transient changes in translocation rate are due to transient changes in the leaf relative water content. The direction of the transient depends on the nature of the osmoticum and the presence or absence of roots.
A simple histological assay to detect virus-like particles in the green alga Cylindrocapsa (Chlorophyta)
Authors: Stanker Larry H. , Hoffman Larry R.
Published: November 2007

A rapid histological assay for the detection of virus-like particles (VLPs) within cells of Cylindrocapsa is reported. Cells containing abundant VLPs can be readily distinguished in this assay with the light microscope following staining with Schiff's reagent. Histochemical staining of the VLP aggregates suggests the particles contain DNA. The reliability of the assay was determined by selecting individual cells which gave a positive test for the presence of VLPs in the assay, and then isolating and processing the same cells for electron microscopy. Ultrastructural examination of such cells clearly confirmed the presence of VLPs. The application of this assay to screen other algae which may contain similar VLPs is discussed.
The genera Sporormiella and Sporormia in east Africa
Authors: Khan Rahmeth S. , Cain R. F.
Published: November 2007

Four new coprophilous species of Sporormiella are described and illustrated: S. macropulchella from Canada, Kenya, Tanzania, and U.S.A.; S. obliqua from Canada, Kenya, Tanzania, Uganda, and U.S.A.; S. similis from Canada, Kenya, Tanzania, and U.S.A.; and S. tenuispora from Kenya, Tanzania, and U.S.A. Many additional records are reported for 18 previously described species, several of which are redescribed from axenic cultures. New records are provided for two of the known species of Sporormia.
Entomophthora thripidum, a new fungal pathogen of Thrips tabaci
Authors: Samson R. A. , Ramakers P. M. J. , Oswald T.
Published: November 2007

Entomophthora thripidum sp. nov. is described and illustrated. The species is pathogenic for Thrips tabaci Lind. (Thysanoptera: Thripidae) and caused epizootics in populations of this species in glasshouses in the Netherlands. Entomophthora thripidum is characterized by spores which are broadly ellipsoidal with a pointed apex and truncate base. Infection is restricted to the abdominal parts of the body and primary spores can be discharged from the living hosts. The secondary spores are similar but smaller than the primary ones. Details about the seasonal history and symptoms of the disease are described. The invalidly published name Empusa weberi Lakon (= Entomophthora weberi (Lakon) Batko) is validated by a Latin diagnosis.
The effect of sodium hypochlorite and gibberellic acid on seed dormancy and germination of wild oats (Avena fatua)
Authors: Hsiao A. I.
Published: November 2007

The seed coverings, including the pericarp and testa of the caryopsis and the hull, arc the main barriers to the exchange of gases and the penetration of exogenous gibberellic acid (GA3) for germination of wild oats (Avena fatua L.). Dormancy was induced in seeds by immersing them in water for 15 minor longer. Dormancy induction was greater in those seeds immersed for up to 1 h in 6% sodium hypochlorite (NaOCl) and then 1 h in water than in those seeds immersed only in water for 1 h. The addition of GA3, to seeds subjected to NaOCl treatment for 15 min or less did not break dormancy, indicating a slow rate of entry, or the exclusion, of GA3, by the seeds. In the presence of GA3, germination increased with increasing exposure to NaOCl. Maximum germination was obtained by immersing dry seeds in NaOCl for 2 h, in water for 1 h, and then incubating the seeds in GA3. Gibberellic acid was not required for complete germination of imbibed, dehulled seeds immersed in NaOCl for 1 h then in water for 1 h, but it was necessary to use 10−4 M GA3 for complete germination of intact seeds that were treated with NaOCl or 2 h then with water for 1 h. Imbibed, dormant seeds that were dehulled and pierced required 10−7 M GA3, to give complete germination in this study. Piercing of the seed coverings enhances GA3, penetration and thus increases the availability of GA3, for germination. NaOCl treatment to the seeds mimics the effects of piercing. NaOCl may also have caused loss of germination inhibitors or rendered these inhibitors susceptible to oxidation. However, prolonged NaOCl treatment resulted in either poor germination or seed disintegration.
Recovery of ectomycorrhizal fungi after exposure to subfreezing temperatures
Authors: France R. C. , Cline M. L. , Reid C. P. P.
Published: November 2007

Seventy-three isolates of eighteen ectomycorrhizal fungi were examined for their growth recovery after a 48-h exposure to −10 °C. Survival of all isolates was 97%. Recovery time to active growth varied between species and within species. Of surviving isolates, 72% initiated growth in less than 2 weeks after thawing. Growth rate was not affected for isolates exhibiting rapid recovery but was significantly lowered for isolates with recovery times of more than 5 weeks. Variation in growth form occurred with some species of Suillus and Xerocomus.
Erratum: Effect of buffered solutions and various anions on vegetative and sexual development in gametophytes of Pteridium aquilinum
Authors: Evans Lance S. , Bozzone Donna M.
Published: November 2007

In the Materials and Methods (p. 780) both the pH levels and the ionic strength of the citrate phosphate buffers were incorrectly reported. Instead of 0.01 M, the ionic strength was 0.0025 M. The buffers reported as being pH 5.8, 5.6, 6.2, 4.8, 4.2, 3.2, and 2.2 were actually 6.1, 6.0, 5.5, 5.1, 4.5, 3.6, and 3.0, respectively.
On the promotion of senescence in Brassica oleracea var. capitata by Alternaria brassicicola and by Botrytis cinerea
Authors: Poapst P. A. , Ramsoomair B. Anne , Gourley C. O.
Published: November 2007

Alternaria brassicicola and Botrytis cinerea stimulated ethylene production in closed culture with floating leaf discs from cabbage (Brassica oleracea var. capitata). Production with A. brassicicola had an observed maximum at 18 °C and was speeded by preculturing the fungus on media containing cabbage components, but which contained little or no methionine.In the absence of cabbage tissue, both organisms demonstrated a latent capacity to generate ethylene from closed shake cultures of Czapek's medium containing L-methionine. With A. brassicicola in a modified Czapek's medium (minus ferrous sulfate) containing 10−3 ML-methionine, there was a stimulation of ethylene production at 18 °C by the addition of Fe2+, Fe3+, Cu2+, ca. 8% carbon dioxide, or the potassium salt of gibberellic acid (GA3). With B. cinerea, 4% carbon dioxide was stimulatory, 29% carbon dioxide was inhibitory, whereas less than 4% oxygen arrested the production of ethylene completely for 48 h.Results suggest that the nature of parasitism of A. brassicicola and B. cinerea on cabbage is characterized by a latent capability to cause the production of, and to produce, the plant-senescing hormone ethylene.
Pollen morphology of Pacific Northwestern Polemonium species in relation to paleoecology and taxonomy
Authors: Mathewes Rolf W.
Published: November 2007

Six morphological types of Polemonium pollen are described, including P. micranthum which is the only taxon considered to be consistently identifiable to species. A key to the pollen types as seen in light microscopy is presented along with light and scanning electron micrographs of each type. The palynological evidence supports the taxonomic treatment of P. uciitiflorum and P. occidentale as subspecies of P. caeruleum, and supports a close affinity between P. pectinatum and P. foliosissimum. Brief summaries of the present-day ecology and distribution of Pacific Northwestern Polemonium species are presented. The application of indicator pollen analysis in Quaternary paleoecology is discussed, with special references to examples of paleoenvironmen-tal inference using Polemonium pollen types.
Effect of sucrose, hormones, and metabolic inhibitors on the development of pollen embryoids in anther cultures of dihaploid Solanum tuberosum
Authors: Sopory Sudhir K.
Published: November 2007

In anther cultures of potato, sucrose played an important part in the development of pollen grains to embryoids. Up to 40% of the anthers responded when sucrose was used at a concentration of 60 g/L. A high sucrose concentration was found to be an essential requirement for the development of embryoids only during the early phase of pollen divisions and this effect could be partially mimicked by glucose. Besides sucrose, hormones were found to be essential to elicit the optimal response in addition to activated charcoal. The insensitivity of pollen divisions to actinomycin D during the early phase suggests that the initial divisions may proceed independently of newly synthesized RNA.
Host specificity and penetration in the mosquito pathogen Coelomomyces psorophorae
Authors: Zebold Stephen L. , Whisler Howard C. , Shemanchuk Joseph A. , Travland Linda B.
Published: November 2007

A variety of the mosquito pathogen, Coelomomyces psorophorae, collected at Fincastle, Alberta, has been maintained in laboratory-reared larvae of Culiseta inornata and in cultures of the copepod, Cyclops vernalis. Despite earlier speculation, the fungus appears to have a relatively broad host range as revealed by preliminary host-specificity studies. Seven of the 12 mosquito species tested became infected. One species, Aedes vexans, known to be a host for C. psorophorae was not infected, confirming experimentally that host-specific varieties of this species of fungus do exist. Staining with a dilute solution of methylene blue revealed that the fungus encysts in definite patterns on the cuticles of both host animals. Penetration occurs through the cuticle and not through the digestive tract. A correlation between attachment and susceptibility was obvious in these limited trials.
Microfungal succession on living leaves of Populus tremuloides
Authors: Wildman H. G. , Parkinson D.
Published: November 2007

The microfungal succession on the surfaces and interior of attached aspen poplar leaves was followed throughout a growing season at three heights in the tree canopy using a number of isolation and observational techniques. The fungal succession on and within the leaves was in general similar to that reported for other angiosperm leaves. The outer sheathing bud scales were colonized by a limited range of fungi, but the enclosed leaves were free from fungal colonization. The adaxial surfaces of young newly expanded leaves were sparsely colonized by fungi. As the leaves matured they were extensively colonized by the common phylloplane fungi (pink and white yeasts, Aureobasidium pullulans, Cladosporium spp., Alternaria alternata, and Epicoccum purpurascens) especially on the adaxial surface. At senescence both leaf surfaces had extensive hyphal growth on them and a greater internal colonization by phylloplane fungi had occurred. Common phylloplane fungi were less frequently isolated from freshly fallen leaves than from the senescent leaves, but a sterile dark species was frequently isolated from within them. The height of the leaves in the canopy was shown to influence the mycoflora of the aspen poplar leaves, with certain species (the yeasts, Aureobasidium pullulans, Cladosporium spp., and Botrytis cinerea) showing changes in their frequency with sampling height.
Structural changes in phi thickenings during primary and secondary growth in roots. 1. Apple (Pyrus malus) Rosaceae
Authors: Weerdenburg Carol Ann , Peterson Carol A.
Published: November 2007

Whole roots and freehand cross sections of apple roots, cleared and stained with a root extract of Chelidonium majus L., revealed the presence of a uniseriate layer of phi thickenings. The layer, externally adjacent to the endodermis, consisted of cells with a heavy deposition of lignin in the thickened midportions of their transverse and radial walls. The thickenings were completely developed within 3–5 mm from the root tip. Lateral root primordia emerged through the phi layer by means of openings in the layer resulting from the removal of entire phi thickenings from the cortical cells. The layer was not continuous from the main to the lateral roots unlike the Casparian band of the endodermis. During secondary growth, the middle lamellae of the cells of the phi layer split, disrupting the regular appearance of the layer. Ultimately, the epidermis and cortex were sloughed off as the periderm, arising in the pericycle, developed to form the most external tissue of the mature root. However, remnants of the phi thickenings were persistent in many areas of the mature root.
Additions to the flora of the Queen Charlotte Islands on limestone
Authors: Roemer Hans L. , Ogilvie R. T.
Published: November 2007

The following montane, subalpine, and alpine species not previously reported from the Queen Charlotte Islands are documented: Astragalus robbinsii, Taraxacum ceratophorum, Pyrola asarifolia, Salix stolonifera, Senecio lugens, Selaginella densa, and Cystopteris montana. Many plants disjunctly distributed and endemic in the Queen Charlotte Islands are found more frequently on limestones than on other rocks. Causes for this concentration on limestones are suggested and related to similar phenomena in Europe.
DEVELOPMENT OF ENVIRONMENTAL EDUCATION SYSTEM USING ONLINE ELEMENT ANALYSIS
Authors: NIIZEKI T. , YOSHIHARA T. , TSUCHIYA K. , KAWASAKI K. , KOMIYA K.
Published: November 2007

We have constructed a network system which enables one to access and analyze environmental data obtained at different and distant laboratories. As a preliminary feasibility test of the system, we studied the elements in the water of the Tesio River using PIXE and ion chromatography. Students used the data online to carry out analysis via internet. We found two factors with different features in calcium from the factor analysis. The comparison of the specific result and relevant geology information has revealed a remarkable presence of Ca2+ which might come from dissolution of limestone in the upper Tesio River. PIXE data gave crucial information to draw such a conclusion. The present system has been found useful in environmental education in universities, online sharing of PIXE data in particular.
ON THE SOFTWARE AND KNOWLEDGE ENGINEERING ASPECTS OF THE EDUCATIONAL PROCESS
Authors: HADZILACOS THANASSIS , KALLES DIMITRIS , POULIOPOULOU MARIA
Published: November 2007

The Hellenic Open University has embarked on a large-scale effort to enhance its textbook-based material with content that demonstrably supports the basic tenets of distance learning. The challenge is to set up a framework that allows for the production-level creation, distribution and consumption of content, and at the same time, evaluate the effort in terms of technological, educational and organizational knowledge gained. This paper presents a model of the educational process that is used as a development backbone and argues about its conceptual and technical practicality at large.
POWER-LAWS f(R) THEORIES ARE COSMOLOGICALLY UNACCEPTABLE
Authors: AMENDOLA LUCA , POLARSKI DAVID , TSUJIKAWA SHINJI
Published: November 2007

In a recent paper,1 we have shown that f(R) = R + μRn modified gravity dark energy models are not cosmologically viable because during the matter era that precedes the accelerated stage the cosmic expansion is given by a ~ t1/2 rather than a ~ t2/3, where a is a scale factor and t is the cosmic time. A recent work by Capozziello et al.2 criticized our results presenting some apparent counter-examples to our claim in f(R) = μRn models. We show here that those particular Rn models can produce an expansion as a ~ t2/3 but this does not connect to a late-time acceleration. Hence, though acceptable f(R) dark energy models might exist, the Rn models presented in Capozziello et al. are not cosmologically viable, confirming our previous results in Ref. 1.
CALCULATING THE EARLY EXERCISE BOUNDARY OF AMERICAN PUT OPTIONS WITH AN APPROXIMATION FORMULA
Authors: ZHU SONG-PING , HE ZHI-WEI
Published: November 2007

Accurately as well as efficiently calculating the early exercise boundary is the key to the highly nonlinear problem of pricing American options. Many analytical approximations have been proposed in the past, aiming at improving the computational efficiency and the easiness of using the formula, while maintaining a reasonable numerical accuracy at the same time. In this paper, we shall present an approximation formula based on Bunch and Johnson's work [6]. After clearly pointing out some errors in Bunch and Johnson's paper [6], we will propose an improved approximation formula that can significantly enhance the computational accuracy, particularly for options of long lifetime.
New Insights into Nitric Oxide Signaling in Plants
Authors: Besson-Bard Angélique , Pugin Alain , Wendehenne David
Published: November 2007

A decade-long investigation of nitric oxide (NO) functions in plants has led to its characterization as a biological mediator involved in key physiological processes. Despite the wealth of information gathered from the analysis of its functions, until recently little was known about the mechanisms by which NO exerts its effects. In the past few years, part of the gap has been bridged. NO modulates the activity of proteins through nitrosylation and probably tyrosine nitration. Furthermore, NO can act as a Ca2+-mobilizing messenger, and researchers are beginning to unravel the mechanisms underlying the cross talk between NO and Ca2+. Nonetheless, progress in this area of research is hindered by our ignorance of the pathways for NO production in plants. This review summarizes the basic concepts of NO signaling in animals and discusses new insights into NO enzymatic sources and molecular signaling in plants.
Patterning Fluid and Elastomeric Surfaces Using Short-Wavelength UV Radiation and Photogenerated Reactive Oxygen Species
Authors: Sanii Babak , Parikh Atul N.
Published: November 2007

Patterning physical, chemical, and biological functions at solid surfaces combines technological development with scientific discoveries in many disparate fields. A variety of top-down and bottom-up approaches has proved successful for applications in the solid state, affording large-area patterning at ever-shrinking length scales. Here we review a collection of recent efforts that highlight the versatility of short-wavelength ultraviolet light and photogenerated reactive oxygen species as a simple and cost-effective means to pattern a variety of challenging materials and thin-film configurations. In particular, we discuss two different classes of materials that present different challenges for patterning: fluid phospholipid bilayers at the buried solid-water interface and the surfaces of bulk elastomers. Despite the use of an identical patterning source, the generation and stabilization of patterns in these two classes of materials follow different mechanisms and produce different functionalities.
Effects of the nitric oxide donor SIN-1 on net hepatic glucose uptake in the conscious dog
Authors: An Zhibo , DiCostanzo Catherine A. , Moore Mary C. , Edgerton Dale S. , Dardevet Dominique P. , Neal Doss W. , Cherrington Alan D.
Published: November 2007

To determine the role of nitric oxide in regulating net hepatic glucose uptake (NHGU) in vivo, studies were performed on three groups of 42-h-fasted conscious dogs using a nitric oxide donor [3-morpholinosydnonimine (SIN-1)]. The experimental period was divided into period 1 (0–90 min) and period 2 (P2; 90–240 min). At 0 min, somatostatin was infused peripherally, and insulin (4-fold basal) and glucagon (basal) were given intraportally. Glucose was delivered intraportally (22.2 μmol·kg−1·min−1) and peripherally (as needed) to increase the hepatic glucose load twofold basal. At 90 min, an infusion of SIN-1 (4 μg·kg−1·min−1) was started in a peripheral vein (PeSin-1, n = 10) or the portal vein (PoSin-1, n = 12) while the control group received saline (SAL, n = 8). Both peripheral and portal infusion of SIN-1, unlike saline, significantly reduced systolic and diastolic blood pressure. Heart rate rose in PeSin-1 and PoSin-1 (96 ± 5 to 120 ± 10 and 88 ± 6 to 107 ± 5 beats/min, respectively, P < 0.05) but did not change in response to saline. NHGU during P2 was 31.0 ± 2.4 and 29.9 ± 2.0 μmol·kg−1·min−1 in SAL and PeSin-1, respectively but was 23.7 ± 1.7 in PoSin-1 ( P < 0.05). Net hepatic carbon retention during P2 was significantly lower in PoSin-1 than SAL or PeSin-1 (21.4 ± 1.2 vs. 27.1 ± 1.5 and 26.1 ± 1.0 μmol·kg−1·min−1). Nonhepatic glucose uptake did not change in response to saline or SIN-1 infusion. In conclusion, portal but not peripheral infusion of the nitric oxide donor SIN-1 inhibited NHGU.
Swim training prevents hyperglycemia in ZDF rats: mechanisms involved in the partial maintenance of β-cell function
Authors: Király Michael A. , Bates Holly E. , Kaniuk Natalia A. , Yue Jessica T. Y. , Brumell John H. , Matthews Stephen G. , Riddell Michael C. , Vranic Mladen
Published: November 2007

Exercise improves glucose tolerance in obese rodent models and humans; however, effects with respect to mechanisms of β-cell compensation remain unexplained. We examined exercise's effects during the progression of hyperglycemia in male Zucker diabetic fatty (ZDF) rats until 19 wk of age. At 6 wk old, rats were assigned to 1) basal-euthanized for baseline values; 2) exercise-swam individually for 1 h/day, 5 days/wk; and 3) controls ( n = 8–10/group). Exercise (13 wk) resulted in maintenance of fasted hyperinsulinemia and prevented increases in fed and fasted glucose ( P < 0.05) compared with sham-exercised and sedentary controls ( P < 0.05). β-Cell function calculations indicate prolonged β-cell adaptation in exercised animals alone. During an intraperitoneal glucose tolerance test (IPGTT), exercised rats had lower 2-h glucose ( P < 0.05) vs. controls. Area-under-the-curve analyses from baseline for IPGTT glucose and insulin indicate improved glucose tolerance with exercise was associated with increased insulin production and/or secretion. β-Cell mass increased in exercised vs. basal animals; however, mass expansion was absent at 19 wk in controls ( P < 0.05). Hypertrophy and replication contributed to expansion of β-cell mass; exercised animals had increased β-cell size and bromodeoxyuridine incorporation rates vs. controls ( P < 0.05). The relative area of GLUT2 and protein kinase B was significantly elevated in exercised vs. sedentary controls ( P < 0.05). Last, we show formation of ubiquitinated protein aggregates, a response to cellular/oxidative stress, occurred in nonexercised 19 wk-old ZDF rats but not in lean, 6 wk-old basal, or exercised rats. In conclusion, improved β-cell compensation through increased β-cell function and mass occurs in exercised but not sedentary ZDF rats and may be in part responsible for improved glucoregulation.
Saccharomyces boulardiiinterferes withShigellapathogenesis by postinvasion signaling events
Authors: Mumy Karen L. , Chen Xinhua , Kelly Ciarán P. , McCormick Beth A.
Published: November 2007

Saccharomyces boulardii is gaining in popularity as a treatment for a variety of diarrheal diseases as well as inflammatory bowel disease. This study was designed to examine the effect of this yeast on infection by Shigella flexneri, a highly infectious and human host-adapted enteric pathogen. We investigated key interactions between the bacteria and host cells in the presence of the yeast in addition to a number of host responses including proinflammatory events and markers. Although the presence of the yeast during infection did not alter the number of bacteria that was able to attach or invade human colon cancer-derived T-84 cells, it did positively impact the tight junction protein zonula occluden-2 and significantly increase the barrier integrity of model epithelia. The yeast also decreased ERK, JNK, and NF-κB activation in response to S. flexneri, events likely responsible for the observed reductions in IL-8 secretion and the transepithelial migration of polymorphonuclear leukocytes across T-84 monolayers. These results, suggesting that the yeast allowed for a dampened inflammatory response, were confirmed in vivo utilizing a highly relevant model of human fetal colonic tissue transplanted into scid mice. Furthermore, a cell-free S. boulardii culture supernatant was also capable of reducing IL-8 secretion by infected T-84 cells. These data suggest that although the use of S. boulardii during infection with S. flexneri may alleviate symptoms associated with the inflammatory response of the host, it would not prevent infection.
Are primed polymorphonuclear leukocytes contributors to the high heparanase levels in hemodialysis patients?
Authors: Cohen-Mazor Meital , Sela Shifra , Mazor Rafi , Ilan Neta , Vlodavsky Israel , Rops Angelique L. , van der Vlag Johan , Cohen Hector I. , Kristal Batya
Published: November 2007

Patients on chronic hemodialysis (HD) are at high risk for developing atherosclerosis and cardiovascular complications. Heparanase, an endoglycosidase that cleaves heparan sulfate (HS) side chains of proteoglycans, is involved in extracellular matrix degradation and, as such, may be involved in the atherosclerotic lesion progression. We hypothesize that heparanase is elevated in HD patients, partly due to its release from primed circulating polymorphonuclear leukocytes (PMNLs), undergoing degranulation. Priming of PMNLs was assessed by levels of CD11b and the rate of superoxide release. Heparanase mRNA expression in PMNLs was determined by RT-PCR. PMNL and plasma levels of heparanase were determined by immunoblotting, immunofluorescence, and flow cytometry analyses. The levels of soluble HS in plasma were measured by a competition ELISA. This study shows that PMNLs isolated from HD patients have higher mRNA and protein levels of heparanase compared with normal control (NC) subjects and that heparanase levels correlate positively with PMNL priming. Plasma levels of heparanase were higher in HD patients than in NC subjects and were further elevated after the dialysis session. In addition, heparanase expression inversely correlates with plasma HS levels. A pronounced expression of heparanase was found in human atherosclerotic lesions. The increased heparanase activity in the blood of HD patients results at least in part from the degranulation of primed PMNLs and may contribute to the acceleration of the atherosclerotic process. Our findings highlight primed PMNLs as a possible source for the increased heparanase in HD patients, posing heparanase as a new risk factor for cardiovascular complications and atherosclerosis.
Endogenous opioids: role in prostaglandin-dependent and -independent fever
Authors: Fraga Daniel , Machado Renes R. , Fernandes Luíz C. , Souza Glória E. P. , Zampronio Aleksander R.
Published: November 2007

This study evaluated the participation of μ-opioid-receptor activation in body temperature (Tb) during normal and febrile conditions (including activation of heat conservation mechanisms) and in different pathways of LPS-induced fever. The intracerebroventricular treatment of male Wistar rats with the selective opioid μ-receptor-antagonist cyclic d-Phe-Cys-Try-d-Trp-Arg-Thr-Pen-Thr-NH2 (CTAP; 0.1–1.0 μg) reduced fever induced by LPS (5.0 μg/kg) but did not change Tb at ambient temperatures of either 20°C or 28°C. The subcutaneous, intracerebroventricular, and intrahypothalamic injection of morphine (1.0–10.0 mg/kg, 3.0–30.0 μg, and 1–100 ng, respectively) produced a dose-dependent increase in Tb. Intracerebroventricular morphine also produced a peripheral vasoconstriction. Both effects were abolished by CTAP. CTAP (1.0 μg icv) reduced the fever induced by intracerebroventricular administration of TNF-α (250 ng), IL-6 (300 ng), CRF (2.5 μg), endothelin-1 (1.0 pmol), and macrophage inflammatory protein (500 pg) and the first phase of the fever induced by PGF2α (500.0 ng) but not the fever induced by IL-1β (3.12 ng) or PGE2 (125.0 ng) or the second phase of the fever induced by PGF2α. Morphine-induced fever was not modified by the cyclooxygenase (COX) inhibitor indomethacin (2.0 mg/kg). In addition, morphine injection did not induce the expression of COX-2 in the hypothalamus, and CTAP did not modify PGE2 levels in cerebrospinal fluid or COX-2 expression in the hypothalamus after LPS injection. In conclusion, our results suggest that LPS and endogenous pyrogens (except IL-1β and prostaglandins) recruit the opioid system to cause a μ-receptor-mediated fever.
Ventilatory long-term facilitation in mice can be observed during both sleep and wake periods and depends on orexin
Authors: Terada Jiro , Nakamura Akira , Zhang Wei , Yanagisawa Masashi , Kuriyama Takayuki , Fukuda Yasuichiro , Kuwaki Tomoyuki
Published: November 2007

Respiratory long-term facilitation (LTF) is a long-lasting (>1 h) augmentation of respiratory motor output that occurs even after cessation of hypoxic stimuli, is serotonin-dependent, and is thought to prevent sleep-disordered breathing such as sleep apnea. Raphe nuclei, which modulate several physiological functions through serotonin, receive dense projections from orexin-containing neurons in the hypothalamus. We examined possible contributions of orexin to ventilatory LTF by measuring respiration in freely moving prepro-orexin knockout mice (ORX-KO) and wild-type (WT) littermates before, during, and after exposure to intermittent hypoxia (IH; 5 × 5 min at 10% O2), sustained hypoxia (SH; 25 min at 10% O2), or sham stimulation. Respiratory data during quiet wakefulness (QW), slow wave sleep (SWS), and rapid-eye-movement sleep were separately calculated. Baseline ventilation before hypoxic stimulation and acute responses during stimulation did not differ between the ORX-KO and WT mice, although ventilation depended on vigilance state. Whereas the WT showed augmented minute ventilation (by 20.0 ± 4.5% during QW and 26.5 ± 5.3% during SWS; n = 8) for 2 h following IH, ORX-KO showed no significant increase (by −3.1 ± 4.6% during QW and 0.3 ± 5.2% during SWS; n = 8). Both genotypes showed no LTF after SH or sham stimulation. Sleep apnea indexes did not change following IH, even when LTF appeared in the WT mice. We conclude that LTF occurs during both sleep and wake periods, that orexin is necessary for eliciting LTF, and that LTF cannot prevent sleep apnea, at least in mice.
Transforming growth factor-β and myostatin signaling in skeletal muscle
Authors: Kollias Helen D. , McDermott John C.
Published: November 2007

The superfamily of transforming growth factor-β (TGF-β) cytokines has been shown to have profound effects on cellular proliferation, differentiation, and growth. Recently, there have been major advances in our understanding of the signaling pathway(s) conveying TGF-β signals to the nucleus to ultimately control gene expression. One tissue that is potently influenced by TGF-β superfamily signaling is skeletal muscle. Skeletal muscle ontogeny and postnatal physiology have proven to be exquisitely sensitive to the TGF-β superfamily cytokine milieu in various animal systems from mice to humans. Recently, major strides have been made in understanding the role of TGF-β and its closely related family member, myostatin, in these processes. In this overview, we will review recent advances in our understanding of the TGF-β and myostatin signaling pathways and, in particular, focus on the implications of this signaling pathway for skeletal muscle development, physiology, and pathology.
Early Defects of GABAergic Synapses in the Brain Stem of a MeCP2 Mouse Model of Rett Syndrome
Authors: Medrihan L. , Tantalaki E. , Aramuni G. , Sargsyan V. , Dudanova I. , Missler M. , Zhang W.
Published: November 2007

Rett syndrome is a neurodevelopmental disorder caused by mutations in the transcriptional repressor methyl-CpG-binding protein 2 (MeCP2) and represents the leading genetic cause for mental retardation in girls. MeCP2-mutant mice have been generated to study the molecular mechanisms of the disease. It was suggested that an imbalance between excitatory and inhibitory neurotransmission is responsible for the behavioral abnormalities, although it remained largely unclear which synaptic components are affected and how cellular impairments relate to the time course of the disease. Here, we report that MeCP2 KO mice present an imbalance between inhibitory and excitatory synaptic transmission in the ventrolateral medulla already at postnatal day 7. Focusing on the inhibitory synaptic transmission we show that GABAergic, but not glycinergic, synaptic transmission is strongly depressed in MeCP2 KO mice. These alterations are presumably due to both decreased presynaptic γ-aminobutyric acid (GABA) release with reduced levels of the vesicular inhibitory transmitter transporter and reduced levels of postsynaptic GABAA-receptor subunits α2 and α4. Our data indicate that in the MeCP2 −/y mice specific synaptic molecules and signaling pathways are impaired in the brain stem during early postnatal development. These observations mandate the search for more refined diagnostic tools and may provide a rationale for the timing of future therapeutic interventions in Rett patients.
Multiparametric Quantum Algebras and the Cosmological Constant
Authors: Krishnan Chethan , Napoli Edoardo Di
Published: November 2007

With a view towards applications for de Sitter, we construct the multiparametricq-deformation of the so(5,ℂ)algebra using the Faddeev-Reshetikhin-Takhtadzhyan (FRT) formalism.
A Philatelic Excursion with Jeff Hunter in Probability and Matrix Theory
Authors: Styan George P. H. , Trenkler Götz
Published: November 2007

We present an excursion with Jeff Hunter, visiting some of his research topics. Specifically, we
will present some facts about certain people whose work seems to have influenced Jeff in his scientific
career; we illustrate our presentation with postage stamps that have been issued in honour of these
people. Our main guide is Hunter’s two-volume book entitled Mathematical Techniques
of Applied Probability (Academic Press, 1983).
Fuzzy Clustering Neural Networks for Real-Time Odor Recognition System
Authors: Karlık Bekir , Yüksek Kemal
Published: November 2007

The aim of this study is to develop a novel fuzzy clustering neural network (FCNN) algorithm as pattern classifiers for real-time odor recognition system. In this type of FCNN, the input neurons activations are derived through fuzzy c mean clustering of the input data, so that the neural system could deal with the statistics of the measurement error directly. Then the performance of FCNN network is compared with the other network which is well-known algorithm, named multilayer perceptron (MLP), for the same odor recognition system. Experimental results show that both FCNN and MLP provided high recognition probability in determining various learn categories of odors, however, the FCNN neural system has better ability to recognize odors more than the MLP network.
Low Dark Current Mesa-Type AlGaN Flame Detectors
Authors: Chen Lung-Chien
Published: November 2007

This study characterizes and reports on the fabrication process of AlGaN flame photodetectors with anAl0.1Ga0.9N/GaNsuperlattice structure. The AlGaN flame photodetectors exhibited a low dark current (∼1.17×10−10A at bias of−5V) and large rejection ratio of photocurrent (∼2.14×10−5A at bias of-5 V) to dark current, which is greater than five orders of magnitude. Responsivity at 350 nm at a bias of-5 V was 0.194 A/W. Quantum efficiency,η, was 0.687 at a reverse bias of 5 V.