bluuebunny/crossref_metadata_2025 huggingface dataset:
A morphological analysis of local variation in Stipa nelsonii and S. richardsonii (Gramineae)
Authors: Scagel R. K. , Maze Jack
Published: June 2008

A putative intermediate between Stipa richardsonii and S. nelsonii was shown to be a large form of S. nelsonii that varied in the direction of S. richardsonii. The putative intermediate did not have seed and had a lower percentage of variable intercorrelations than either S. nelsonii or S. richardsonii, indicating that gene flow may have occurred between S. richardsonii and S. nelsonii to produce the putative intermediates. Stipa nelsonii was more variable than either S. richardsonii or the putative intermediates. This greater variability of S. nelsonii, correlated with the taxon's greater subspecific differentiation, represents an example of the Kluge–Kerfoot phenomenon. Quantification of intra-individual variation (= developmental variability) serves to extend the Kluge–Kerfoot phenomena to a developmental level.
Cytological aspects of events occurring after the formation of primary haustoria in barley leaves infected with powdery mildew
Authors: Tosa Y. , Shishiyama J.
Published: June 2008

Cellular responses occurring after the formation of normal primary haustoria were examined in barley leaves inoculated with Erysiphe graminis f. sp. hordei, race I or IX. Collapsed mesophyll cells that fluoresced appeared specifically in incompatible combinations (infection types 0′, 0-1, 1, and 1-2). In moderately resistant combinations (infection types 1 and 1-2), conidia were produced 4–5 days after inoculation in spite of the extensive collapse of mesophyll cells, suggesting that fungal development was not completely suppressed by this cell collapse. In highly resistant (infection type 0′) and resistant (infection type 0-1) combinations, most of the epidermal cells that were subject to secondary penetration attempts prevented the formation of normal secondary haustoria by collapsing hypersensitively. The appearance of fluorescent mesophyll cells was correlated with the race-specific expression of [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text], which are major genes for resistance identified in cultivar H.E.S.4, Turkey 290, Russian No. 12, and Hanna, respectively. Further, the appearance of fluorescent or browned epidermal cells associated with secondary penetrations was also correlated with the race-specific expression of [Formula: see text], [Formula: see text], and [Formula: see text]. Therefore, it is suggested that these three genes control both epidermal and mesophyll responses.
Fine-root biomass and nutrient cycling in Aristida stricta in a North Carolina coastal plain savanna
Authors: Saterson Kathryn A. , Vitousek Peter M.
Published: June 2008

Seasonal changes in total fine-root biomass and the allocations of nitrogen and phosphorus to roots, root crowns, and leaves of Aristida stricta were measured on a North Carolina coastal plain savanna. Total fine-root biomass was determined from sequential root cores taken over 12 months. Total root biomass decreased from spring to late fall and then increased in winter. Root production and turnover estimates indicate that this low-fertility savanna has a relatively large root biomass and slow turnover. The pattern of allocation of biomass, nitrogen, and phosphorus to different tissues of Aristida stricta indicates that throughout the year the greatest percentage of biomass and nutrients is in roots.
Structural aspects of pollination in Amelanchier alnifolia (Maloideae)
Authors: Olson A. Randall
Published: June 2008

The blossom structure of Amelanchier alnifolia conforms to the typical pattern of the Maloideae (Rosaceae). The bowl-shaped perianth of the open flower and the staminal whorls around the stigmas facilitate pollination by foraging insects. Each of the five stigmas is characterized by large vacuolate papillae. Stigmatic secretions begin during petal elongation resulting in a sticky lipidic exudate on the papillate surface at full bloom. The tricolpate pollen adhering to the wet stigmas produce pollen tubes that penetrate the stigmas in between adjacent papillae and grow through the intercellular spaces of the transmitting tissue toward the ovarian locules. Although the blossom structure encourages entomophily, anther proximity to the stigmas just prior to anthesis in conjunction with the preanthesis shedding of pollen suggests a developmental mechanism that promotes a limited amount of autogamy.
The effect of light-dependent oxygen consumption on nitrogenase activity in Anabaena cylindrica
Authors: Smith Donald L. , Patriquin David G. , Dijak Margareta , Curry George M.
Published: June 2008

Light-dependent oxygen consumption (LDOC) was observed in isolated heterocysts and in intact and sonicated CO2-fixing Anabaena cylindrica cells. The rate of LDOC in heterocysts was about three times that of CO2-fixing cells. Photosynthetic oxygen production by A. cylindrica became light saturated at 0.3 to 0.5 mW cm−2. LDOC and nitrogenase activity (acetylene reduction) increased with light intensity up to 2.5 mW cm−2 and incubation under air resulted in much larger relative acetylene reduction increases than incubation under N2. Carbonyl cyanide-m-chlorophenyl-hydrazone, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, and cyanide did not affect the rate of LDOC in isolated heterocysts or cell-free preparations of CO2-fixing cells. However, all three substances induced LDOC in CO2-fixing cells. Heat treatment (100 °C for 1 min) caused a doubling of LDOC. Depletion of reduced carbon reserves by dark incubation caused a similar decrease in LDOC and dark respiration. The higher rates of LDOC observed in heat-treated materials were removed by catalase, but not by superoxide dismutase. Catalase injection released half of the O2 consumed through LDOC by heated preparations. LDOC increased with temperature up to 85 °C, and increased threefold with pH between pH 10 and 11.5. The possibility that LDOC may act to protect the nitrogenase of the heterocyst from oxygen inactivation is discussed.
Effect of three weeds on the growth and mycorrhizal infection of black walnut seedlings
Authors: Ponder Jr. Felix
Published: June 2008

The effect of unincorporated and incorporated litter and extracts of broom-sedge, fescue, and blackberry on the mycorrhizal development and growth of black walnut seedlings was investigated in two greenhouse experiments. Seedling growth varied with method of litter application. Only fescue extract decreased growth in the extract experiment, but unincorporated and incorporated broom-sedge litter significantly (P ≤ 0.05) reduced seedling total dry weight below that of mycorrhizal control seedlings. The total dry weight of seedlings in incorporated fescue litter was reduced by 47%. The number of mycorrhizal infected root segments on seedlings grown in unincorporated litter was more than twice the number of infected roots on seedlings grown in incorporated litters. Significantly fewer mycorrhizal roots were found on seedlings grown with fescue and broom-sedge litters than on mycorrhizal control seedlings. On the average, incorporation of litter increased the percentage of leaf phosphorus, but the shoot absorption of phosphorus was considerably less for seedlings grown in incorporated fescue litter compared with unincorporated fescue litter. Seedlings grown in fescue extract had 33% less phosphorus than control seedlings. Except for possible interference with mycorrhizal development when litter was incorporated, there was no evidence to suggest that blackberry litter contains substances that are allelopathic to black walnut.
Constancy of enzyme electrofocusing patterns in a stand of the lichen Umbilicaria mammulata
Authors: Hageman C. , Fahselt D.
Published: June 2008

Thalli of the lichen Umbilicaria mammulata (Ach.) Tuck, were collected from one site, 24 at each of five different sampling times, over a period of 1 year. Protein extracts from each individual thallus were subjected to isoelectric focusing, followed by specific staining for eight enzyme systems (mannitol dehydrogenase, isocitrate dehydrogenase, 6-phosphogluconate dehydrogenase, glucose-6-phosphate dehydrogenase, glutamate dehydrogenase, superoxide dismutase, esterase, and alkaline phosphatase). A total of 55 bands were resolved, 25 of which were constant in all thalli through all sampling dates. Principal components analysis of the electromorph data showed the existence of groups corresponding to sets of thalli collected at the same times; esterase and alkaline phosphatase variation were primarily responsible for these groupings. Banding patterns of 6-phosphogluconate dehydrogenase and superoxide dismutase were constant regardless of date of collection. Most bands of glucose-6-phosphate dehydrogenase and glutamate dehydrogenase were consistent through all sampling times, but each system exhibited one band that differed in frequency from one collection date to another. Electromorphs of mannitol dehydrogenase and isocitrate dehydrogenase exhibited only minor variability. Dehydrogenase enzymes, since they tended to vary least from one sampling time to the next, can thus be used more readily for taxonomic purposes. If esterases and alkaline phosphatases are to be applied as taxonomic criteria, samples for comparison should be collected simultaneously.
Ultrastructure of mature and fired gun cells of Haptoglossa mirabilis
Authors: Robb Jane , Lee B.
Published: June 2008

Haptoglossa mirabilis is a parasitic oomycete which infects its rotifer host by means of a specialized vegetative cell, the gun cell. The dominant feature of gun cell architecture is the attack apparatus, which consists of two extracellular components, the injection tube and the missile, and an intracellular component, the vacuolar system. At the anterior end of the cell, the wall is deeply invaginated to form the various sections of the injection tube: the bore, the missile chamber, the tail housing, and the hollow tail which is folded within the housing. The missile, also complex, is attached anterior to the tail and rests within the missile chamber at the apical end of the cell. The vacuolar system includes the posterior, anterior, and apical vacuoles. On attack, the missile is fired from the cell; the injection tube is completely everted and a portion of the protoplast is propelled at high speed into the host, in the form of a walled sporidium. A model is proposed to explain the mechanism of action of the gun cell.
The bryophytes of Nachvak, northern Labrador, with additional records from Saglek
Authors: Hedderson Terry A. , Brassard Guy R.
Published: June 2008

One hundred and thirty-four species of mosses and 18 species of liverworts are reported from Nachvak Fiord and 22 mosses are reported from Saglek Fiord. Nineteen of the mosses had not previously been reported from Labrador and 49 are new to northern Labrador. Seven of the liverworts are new to Labrador. Brophyte species new to eastern North America are Anastrophyllum assimile, Hygrophypnum cochlearifolium (possibly) and Lophozia cavifolia. The record of Lophozia cavifolia represents an addition to the hepatic flora of North America (excluding Greenland). The North American distributions of Hydrogrimmia mollis, Marsupella revoluta and Trichostomum arcticum are mapped. The high incidence of disjunct species in the bryoflora of the Torngat Mountains is discussed in relation to the proposed glacial history of the area.
A comparative study of initiation and development of embryogenic callus from haploid embryos of several barley cultivars. II. Cytophotometry of embryos and callus
Authors: Kott L. S. , Flack S. , Kasha K. J.
Published: June 2008

Cells of haploid barley embryos (Hordeum vulgare L. 'Bruce', 'Perth', and 'Klages') and callus cells originating from embryos were cytophotometrically examined to determine the ploidy level. Specific embryo tissues regularly exhibited predictable ploidies and smaller embryos had a higher percentage of haploid cells than larger embryos of the same age. The predominantly haploid cells of the scutellar epidermis of the embryo initiated callus which generally, at least initially, was haploid. Monitoring of the ploidy evolution of these haploid calli showed that over a 6-month period each line exhibited its own unique rate of polyploidization, although lines of the same cultivar showed similar trends. Accumulation of cells at the diploid level was often a characteristic of these cultures.
SINGLE-CAVITY WAVELENGTH-SWITCHED FIBER RING LASER BASED ON FIBER BENDING EFFECT IN MACH–ZEHNDER INTERFEROMETER
Authors: HAN JAE-HO
Published: June 2008

The author has experimentally demonstrated a wavelength switching single cavity fiber ring laser incorporating a Mach–Zehnder interferometer with two optical wavelength thin film filters. By changing the radius of the fiber bending in one path, the wavelength gradually shifts from one wavelength to another or forms a dual-wavelength operation due to the laser gain competition depending on the path loss.
ELECTROLYTIC TRANSPORT THROUGH CYLINDRICAL ETCHED PORES IN POLYETHYLENE TEREPTHALATE TRACK-ETCHED MEMBRANE
Authors: KUMAR SANJEEV , CHAKARVARTI S. K.
Published: June 2008

In the present work, electrolytic transport phenomena is studied for different electrolytes ( LiCl , NaCl , KCl of different concentrations) at room temperature (25 ± 2° C ) through etched pores with different diameters having cylindrical shape in track-etched membranes of polyethylene terepthalate (PET) with pore density of the order of 106/cm2. Electric potential has been used as the driving force. It has been observed that electrolytic transport through pores is different for different electrolytes, depending strongly on size of cations and is independent of size of anions. In the case of cylindrical pores, there has not been found appreciable change in forward and backward resistances.
FIXED PARAMETER ALGORITHMS FOR THE MINIMUM WEIGHT TRIANGULATION PROBLEM
Authors: BORGELT MAGDALENE GRANTSON , BORGELT CHRISTIAN , LEVCOPOULOS CHRISTOS
Published: June 2008

We discuss and compare four fixed parameter algorithms for finding the minimum weight triangulation of a simple polygon with (n – k) vertices on the perimeter and k vertices in the interior (hole vertices), that is, for a total of n vertices. All four algorithms rely on the same abstract divide-and-conquer scheme, which is made efficient by a variant of dynamic programming. They are essentially based on two simple observations about triangulations, which give rise to triangle splits and paths splits. While each of the first two algorithms uses only one of these split types, the last two algorithms combine them in order to achieve certain improvements and thus to reduce the time complexity. By discussing this sequence of four algorithms we try to bring out the core ideas as clearly as possible and thus strive to achieve a deeper understanding as well as a simpler specification of these approaches. In addition, we implemented all four algorithms in Java and report results of experiments we carried out with this implementation.
ON MINIMUM AREA PLANAR UPWARD DRAWINGS OF DIRECTED TREES AND OTHER FAMILIES OF DIRECTED ACYCLIC GRAPHS
Authors: FRATI FABRIZIO
Published: June 2008

It has been shown that there exist planar digraphs that require exponential area in every upward straight-line planar drawing. On the other hand, upward poly-line planar drawings of planar graphs can be realized in Θ(n2) area. In this paper we consider families of DAGs that naturally arise in practice, like DAGs whose underlying graph is a tree (directed trees), is a bipartite graph (directed bipartite graphs), or is an outerplanar graph (directed outerplanar graphs). Concerning directed trees, we show that optimal Θ(n log n) area upward straight-line/poly-line planar drawings can be constructed. However, we prove that if the order of the neighbors of each node is assigned, then exponential area is required for straight-line upward drawings and quadratic area is required for poly-line upward drawings, results surprisingly and sharply contrasting with the area bounds for planar upward drawings of undirected trees. After having established tight bounds on the area requirements of planar upward drawings of several families of directed trees, we show how the results obtained for trees can be exploited to determine asymptotic optimal values for the area occupation of planar upward drawings of directed bipartite graphs and directed outerplanar graphs.
FREE VIBRATION OF SEMI-RIGIDLY CONNECTED PILES EMBEDDED IN SOILS WITH DIFFERENT SUBGRADES
Authors: YESILCE YUSUF , CATAL HIKMET H.
Published: June 2008

This paper is concerned with the free vibration analysis of Timoshenko piles partially embedded in elastic soil, semi-rigidly connected at the upper end, and subjected to an axial force. The pile is divided into three regions: the pile portion above the soil constitutes the first region, while the second and third regions are the pile portion that is embedded in two different layers of the soil type. The pile material is assumed to be linearly elastic and the axial force is constant along the pile length. The soil is idealized by the Winkler model and the semi-rigid connection of the pile is modeled by a rotational spring. The natural frequencies of the piles are calculated from the transfer matrix for different axial forces, rotational spring constants, subgrade reaction moduli and embedded lengths of the pile. The results indicate that the natural frequency of the pile decreases as the axial force increases. Further, the increase in the stiffness of the rotational spring at the upper end of the pile causes only a small increase in the natural frequency. Finally, both the pile length and the subgrade reaction of the soil influence significantly the natural frequency of the pile.
ON INSTABILITY OF SINGLE-WALLED CARBON NANOTUBES WITH A VACANCY DEFECT
Authors: WANG Q. , VARADAN V. K. , XIANG Y. , HAN Q. K. , WEN B. C.
Published: June 2008

This technical note is concerned with the buckling of single-walled carbon nanotubes with one atomic vacancy. An elastic beam theory is developed to predict the buckling strain of defective CNTs, and the strain prediction via the continuum mechanics model is verified from comparison studies by molecular dynamics simulations. The results demonstrate the effectiveness of the continuum mechanics theory for longer CNTs. In addition, a local kink is revealed in the morphology of the buckling of shorter defective CNTs via molecular dynamics.
SCHEME FOR IMPLEMENTING QUANTUM DENSE CODING USING MULTI-ATOM IN CAVITY QED
Authors: YE LIU , FANG BAO-LONG
Published: June 2008

We propose an experimentally feasible scheme for implementing quantum dense coding in cavity QED. In this scheme, the multi-atoms interact simultaneously with a highly detuned cavity mode, and are driven by a strong classical field. The scheme is insensitive to the cavity decay and the thermal field. Only one interaction between atoms and cavity is required. Multi-atom's GHZ-states can be exactly distinguished via detecting the atomic state, and the quantum dense coding can be realized in a simple way.
A NEW QUANTUM ALGORITHM FOR SOLVING THE MINIMUM SEARCHING PROBLEM
Authors: KOWADA LUIS ANTONIO BRASIL , LAVOR CARLILE , PORTUGAL RENATO , DE FIGUEIREDO CELINA M. H.
Published: June 2008

In this paper, we propose a new quantum algorithm for solving the minimum searching problem. This algorithm has the same order of time and space complexities as the algorithm proposed by Dürr and Høyer, but it provides a quadratic reduction in the number of measurements. In addition to the correctness and complexity analysis of the algorithm, we present simulation results considering an NP-hard problem.
QUANTUM ENTANGLEMENT IN THE SYSTEM OF TWO SPIN-1/2 PARTICLES WITH HEISENBERG EXCHANGE INTERACTION IN THE PRESENCE OF A SINGLE-MODE VACUUM FIELD
Authors: ZHANG GUO-FENG
Published: June 2008

The nonclassical properties of two spin-1/2 particles with Heisenberg exchange interaction in a single-mode vacuum field are investigated. By using the quantum reduced entropy, we demonstrate that the ratio ka between Heisenberg exchange interaction constant difference (J - Jz) and the spin-field coupling constant Ω can affect the feature of the entanglement significantly. It is found that the entanglement of the system evolves periodically with time, the evolvement period of the entanglement between two spin-1/2 particles and the field increases with the increasing ka, which is true for the single spin-field entanglement, but that is contrary for the entanglement between the two spin particles. Our results show that three entangled states of two spins-field, spin–spin, and spin-field can be prepared via two spin-1/2 particles interacting with a single-mode vacuum field. We also characterize the field state by using Mandel's Q parameter, it is proved that the nonclassical properties of the field state will get weaker with the increasing ka and are dramatically different from those in the case of selective measurement for spin.
CONTROLLED TELEPORTATION OF ELECTRON SPIN STATE IN QUANTUM DOT VIA SINGLE PHOTON
Authors: WANG YAN-WEI , WANG MING-FENG , ZHENG YI-ZHUANG
Published: June 2008

A controlled quantum teleportation scheme of electron spin state in a quantum dot is proposed. With the entanglement generating through the interaction between the quantum dots in microcavities and a single photon, the controlled teleportation can be implemented using Faraday rotation and single photon measurements. The scheme can be easily generalized to multi-qubit system.
ENTANGLEMENT OF SUPERPOSITION OF MULTI-STATES
Authors: LI SONG-SONG , HUANG YI-BIN
Published: June 2008

In this letter, we investigate the entanglement of superposition of multi-states. Three cases are considered when the states in the superposition are mutually biorthogonal, mutually orthogonal and nonorthogonal. The relations between the entanglement of superposition and the entanglements of the superposed states are explored.
LIMITATIONS OF SOME SIMPLE ADIABATIC QUANTUM ALGORITHMS
Authors: IOANNOU LAWRENCE M. , MOSCA MICHELE
Published: June 2008

Let H(t) = (1 - t/T)H0 + (t/T)H1, t ∈ [0,T], be the Hamiltonian governing an adiabatic quantum algorithm, where H0 is diagonal in the Hadamard basis and H1 is diagonal in the computational basis. We prove that H0 and H1 must each have at least two large mutually-orthogonal eigenspaces if the algorithm's running time is to be subexponential in the number of qubits. We also reproduce the optimality proof of Farhi and Gutmann's search algorithm in the context of this adiabatic scheme; because we only consider initial Hamiltonians that are diagonal in the Hadamard basis, our result is slightly stronger than the original.
Optical imaging of cell mass and growth dynamics
Authors: Popescu Gabriel , Park YoungKeun , Lue Niyom , Best-Popescu Catherine , Deflores Lauren , Dasari Ramachandra R. , Feld Michael S. , Badizadegan Kamran
Published: June 2008

Using novel interferometric quantitative phase microscopy methods, we demonstrate that the surface integral of the optical phase associated with live cells is invariant to cell water content. Thus, we provide an entirely noninvasive method to measure the nonaqueous content or “dry mass” of living cells. Given the extremely high stability of the interferometric microscope and the femtogram sensitivity of the method to changes in cellular dry mass, this new technique is not only ideal for quantifying cell growth but also reveals spatially resolved cellular and subcellular dynamics of living cells over many decades in a temporal scale. Specifically, we present quantitative histograms of individual cell mass characterizing the hypertrophic effect of high glucose in a mesangial cell model. In addition, we show that in an epithelial cell model observed for long periods of time, the mean squared displacement data reveal specific information about cellular and subcellular dynamics at various characteristic length and time scales. Overall, this study shows that interferometeric quantitative phase microscopy represents a noninvasive optical assay for monitoring cell growth, characterizing cellular motility, and investigating the subcellular motions of living cells.
Pregnancy-upregulated nonubiquitous calmodulin kinase induces ligand-independent EGFR degradation
Authors: Deb Tushar B. , Coticchia Christine M. , Barndt Robert , Zuo Hong , Dickson Robert B. , Johnson Michael D.
Published: June 2008

We describe here an important function of the novel calmodulin kinase I isoform, pregnancy-upregulated nonubiquitous calmodulin kinase (Pnck). Pnck (also known as CaM kinase Iβ2) was previously shown to be differentially overexpressed in a subset of human primary breast cancers, compared with benign mammary epithelial tissue. In addition, during late pregnancy, Pnck mRNA was shown to be strongly upregulated in epithelial cells of the mouse mammary gland exhibiting decreased proliferation and terminal differentiation. Pnck mRNA is also significantly upregulated in confluent and serum-starved cells, compared with actively growing proliferating cells (Gardner HP, Seung HI, Reynolds C, Chodosh LA. Cancer Res 60: 5571–5577, 2000). Despite these suggestive data, the true physiological role(s) of, or the signaling mechanism(s) regulated by Pnck, remain unknown. We now report that epidermal growth factor receptor (EGFR) levels are significantly downregulated in a ligand-independent manner in human embryonic kidney-293 (HEK-293) cells overexpressing Pnck. MAP kinase activation was strongly inhibited by EGFR downregulation in the Pnck-overexpressing cells. The EGFR downregulation was not the result of reduced transcription of the EGFR gene but from protea-lysosomal degradation of EGFR protein. Knockdown of endogenous Pnck mRNA levels by small interfering RNA transfection in human breast cancer cells resulted in upregulation of unliganded EGFR, consistent with the effects observed in the overexpression model of Pnck-mediated ligand-independent EGFR downregulation. Pnck thus emerges as a new component of the poorly understood mechanism of ligand-independent EGFR degradation, and it may represent an attractive therapeutic target in EGFR-regulated oncogenesis.
Role of desmin in active force transmission and maintenance of structure during growth of urinary bladder
Authors: Scott R. Sjuve , Li Z. , Paulin D. , Uvelius B. , Small J. V. , Arner A.
Published: June 2008

Role of the intermediate filament protein desmin in hypertrophy of smooth muscle was examined in desmin-deficient mice (Des−/−). A partial obstruction of the urethra was created, and after 9–19 days bladder weight increased approximately threefold in both Des−/− and wild type (Des+/+) animals. Bladder growth was associated with the synthesis of actin and myosin. In the hypertrophic Des+/+ bladder, the relative content of desmin increased. In Des−/−mice, desmin was absent. No alterations in the amount of vimentin were observed. Although Des−/− obstructed bladders were capable of growth, they had structural changes with a partial disruption of the wall. Des−/−bladders had slightly lower passive stress and significantly lower active stress compared with Des+/+. Des−/−preparations had lower shortening velocity. During hypertrophy, these structural and mechanical alterations in the Des−/−urinary bladder became more pronounced. In conclusion, desmin in the bladder smooth muscle is not needed for growth but has a role in active force transmission and maintenance of wall structure.
NEFA minimal model parameters estimated from the oral glucose tolerance test and the meal tolerance test
Authors: Boston Ray C. , Moate Peter J.
Published: June 2008

The kinetics of nonesterified fatty acid (NEFA) metabolism in humans requires quantification to facilitate understanding of diseases like type 1 and 2 diabetes, metabolic syndrome, and obesity, and the mechanisms underpinning various interventions. Oral glucose tolerance tests (OGTT) and glucose meal tolerance tests (MTT) are potentially useful procedures for enabling quantification of NEFA kinetics because they both cause transitory, but substantial, declines and then rebounds in plasma NEFA concentrations in response to physiologically relevant increases in plasma glucose. The Boston MINIMAL model of NEFA kinetics was developed to analyze data from the intravenous glucose tolerance test (IVGTT), but in this work, we present for the first time its application to modeling NEFA data from both OGTT and MTT studies. This model enables estimation of SFFA(μmol·l−1·min−1) (a parameter describing the maximum rate of lipolysis), and KFFA(%/min) (a parameter related to NEFA oxidation rate). The model could well describe the trajectories of NEFA concentrations following an OGTT ( R2in excess of 0.97) but was not as successful with the MTT ( R2> 0.65). Model parameters derived from analysis of OGTT and MTT data were well identified with coefficients of variation generally less than 15%. Type 2 diabetes, body mass index, and dietary treatment (high-fat vs. high-glycemic-index diets) were all shown to have significant effects on model parameters. Modeling plasma NEFA concentrations over 24 h has helped to identify and quantify the extent that periprandial NEFA peaks and nocturnal elevation in plasma NEFA can be accounted for by our model.
Dynamic Population Coding of Category Information in Inferior Temporal and Prefrontal Cortex
Authors: Meyers Ethan M. , Freedman David J. , Kreiman Gabriel , Miller Earl K. , Poggio Tomaso
Published: June 2008

Most electrophysiology studies analyze the activity of each neuron separately. While such studies have given much insight into properties of the visual system, they have also potentially overlooked important aspects of information coded in changing patterns of activity that are distributed over larger populations of neurons. In this work, we apply a population decoding method to better estimate what information is available in neuronal ensembles and how this information is coded in dynamic patterns of neural activity in data recorded from inferior temporal cortex (ITC) and prefrontal cortex (PFC) as macaque monkeys engaged in a delayed match-to-category task. Analyses of activity patterns in ITC and PFC revealed that both areas contain “abstract” category information (i.e., category information that is not directly correlated with properties of the stimuli); however, in general, PFC has more task-relevant information, and ITC has more detailed visual information. Analyses examining how information coded in these areas show that almost all category information is available in a small fraction of the neurons in the population. Most remarkably, our results also show that category information is coded by a nonstationary pattern of activity that changes over the course of a trial with individual neurons containing information on much shorter time scales than the population as a whole.
On a Two‐Variable p‐Adic lq‐Function
Authors: Kim Min-Soo , Kim Taekyun , Park D. K. , Son Jin-Woo
Published: June 2008

We prove that a two‐variable p‐adic lq‐function has the series expansion
which interpolates the values , whenever n is a nonpositive integer. The proof of this original construction is
due to Kubota and Leopoldt in 1964, although the method given in this note
is due to Washington.
Generalized Mann Iterations for Approximating Fixed Points of a Family of Hemicontractions
Authors: Hu Liang-Gen , Xiao Ti-Jun , Liang Jin
Published: June 2008

This paper concerns common fixed points for a finite family of hemicontractions or a finite family of strict pseudocontractions on uniformly convex Banach spaces. By introducing a new iteration process with error term, we obtain sufficient and necessary conditions, as well as sufficient conditions, for the existence of a fixed point. As one will see, we derive these strong convergence theorems in uniformly convex Banach spaces and without any requirement of the compactness on the domain of the mapping. The results given in this paper extend some previous theorems.
Fasudil-induced hypoxia-inducible factor-1α degradation disrupts a hypoxia-driven vascular endothelial growth factor autocrine mechanism in endothelial cells
Authors: Takata Keiko , Morishige Ken-ichirou , Takahashi Toshifumi , Hashimoto Kae , Tsutsumi Seiji , Yin Limei , Ohta Tsuyoshi , Kawagoe Jun , Takahashi Kazuhiro , Kurachi Hirohisa
Published: June 2008

Hypoxic response of endothelial cells (EC) is an important component of tumor angiogenesis. Especially, hypoxia-inducible factor-1 (HIF-1)–dependent EC-specific mechanism is an essential component of tumor angiogenesis. Recently, the Rho/Rho-associated kinase (ROCK) signaling has been shown to play a key role in HIF-1α induction in renal cell carcinoma and trophoblast. The present study was designed to investigate whether low oxygen conditions might modulate HIF-1α expression through the Rho/ROCK signaling in human umbilical vascular ECs (HUVEC). Pull-down assay showed that hypoxia stimulated RhoA activity. Under hypoxic conditions, HUVECs transfected with small interfering RNA of RhoA and ROCK2 exhibited decreased levels of HIF-1α protein compared with nontargeted small interfering RNA transfectants, whereas HIF-1α mRNA levels were not altered. One of ROCK inhibitors, fasudil, inhibited hypoxia-induced HIF-1α expression without altering HIF-1α mRNA expression. Furthermore, proteasome inhibitor prevented the effect of fasudil on HIF-1α expression, and polyubiquitination was enhanced by fasudil. These results suggested that hypoxia-induced HIF-1α expression is through preventing HIF-1α degradation by activating the Rho/ROCK signaling in ECs. Furthermore, hypoxia induced both vascular endothelial growth factor (VEGF) and VEGF receptor-2 expression through the Rho/ROCK/HIF-1α signaling in HUVECs. Thus, augmented VEGF/VEGF receptor-2 autocrine mechanism stimulated HUVEC migration under hypoxic conditions. In summary, the Rho/ROCK/HIF-1α signaling is an essential mechanism for hypoxia-driven, VEGF-mediated autocrine loop in ECs. Therefore, fasudil might have the antimigratory effect against ECs in tumor angiogenesis. [Mol Cancer Ther 2008;7(6):1551–61]
α-Catenin overrides Src-dependent activation of β-catenin oncogenic signaling
Authors: Inge Landon J. , Rajasekaran Sigrid A. , Wolle Daniel , Barwe Sonali P. , Ryazantsev Sergey , Ewing Charles M. , Isaacs William B. , Rajasekaran Ayyappan K.
Published: June 2008

Loss of α-catenin is one of the characteristics of prostate cancer. The catenins (α and β) associated with E-cadherin play a critical role in the regulation of cell-cell adhesion. Tyrosine phosphorylation of β-catenin dissociates it from E-cadherin and facilitates its entry into the nucleus, where β-catenin acts as a transcriptional activator inducing genes involved in cell proliferation. Thus, β-catenin regulates cell-cell adhesion and cell proliferation. Mechanisms controlling the balance between these functions of β-catenin invariably are altered in cancer. Although a wealth of information is available about β-catenin deregulation during oncogenesis, much less is known about how or whether α-catenin regulates β-catenin functions. In this study, we show that α-catenin acts as a switch regulating the cell-cell adhesion and proliferation functions of β-catenin. In α-catenin-null prostate cancer cells, reexpression of α-catenin increased cell-cell adhesion and decreased β-catenin transcriptional activity, cyclin D1 levels, and cell proliferation. Further, Src-mediated tyrosine phosphorylation of β-catenin is a major mechanism for decreased β-catenin interaction with E-cadherin in α-catenin-null cells. α-Catenin attenuated the effect of Src phosphorylation by increasing β-catenin association with E-cadherin. We also show that α-catenin increases the sensitivity of prostate cancer cells to a Src inhibitor in suppressing cell proliferation. This study reveals for the first time that α-catenin is a key regulator of β-catenin transcriptional activity and that the status of α-catenin expression in tumor tissues might have prognostic value for Src targeted therapy. [Mol Cancer Ther 2008;7(6):1386–97]
Gambogic acid is an antagonist of antiapoptotic Bcl-2 family proteins
Authors: Zhai Dayong , Jin Chaofang , Shiau Chung-wai , Kitada Shinichi , Satterthwait Arnold C. , Reed John C.
Published: June 2008

The natural product gambogic acid (GA) has been reported to have cytotoxic activity against tumor cells in culture and was identified as an active compound in a cell-based high-throughput screening assay for activators of caspases, proteases involved in apoptosis. Using the antiapoptotic Bcl-2 family protein, Bfl-1, as a target for screening of a library of natural products, we identified GA as a competitive inhibitor that displaced BH3 peptides from Bfl-1 in a fluorescence polarization assay. Analysis of competition for BH3 peptide binding revealed that GA inhibits all six human Bcl-2 family proteins to various extents, with Mcl-1 and Bcl-B the most potently inhibited [concentrations required for 50% inhibition (IC50), <1μmol/L]. Competition for BH3 peptide binding was also confirmed using a time-resolved fluorescence resonance energy transfer assay. GA functionally inhibited the antiapoptotic Bcl-2 family proteins as shown by experiments using isolated mitochondria in which recombinant purified Bcl-2 family proteins suppress SMAC release in vitro, showing that GA neutralizes their suppressive effects on mitochondria in a concentration-dependent manner. GA killed tumor cell lines via an apoptotic mechanism, whereas analogues of GA with greatly reduced potency at BH3 peptide displacement showed little or no cytotoxic activity. However, GA retained cytotoxic activity against bax−/−bak−/− cells in which antiapoptotic Bcl-2 family proteins lack a cytoprotective phenotype, implying that GA also has additional targets that contribute to its cytotoxic mechanism. Altogether, the findings suggest that suppression of antiapoptotic Bcl-2 family proteins may be among the cytotoxic mechanisms by which GA kills tumor cells. [Mol Cancer Ther 2008;7(6):1639–46]
Eps8 decreases chemosensitivity and affects survival of cervical cancer patients
Authors: Chen Yun-Ju , Shen Meng-Ru , Chen Yen-Jen , Maa Ming-Chei , Leu Tzeng-Horng
Published: June 2008

The oncoprotein Eps8 facilitates proliferation in fibroblasts and colon cancer cells. However, its role in human cervical cancer is unclear. By immunohistochemical staining and Western blotting, aberrant Eps8 expression was observed in cervical carcinoma compared with normal cervical epithelial cells. Clinicopathologic analysis of 45 patients indicated that Eps8 expression was associated with parametrium invasion and lymph node metastasis, two major poor prognostic factors for early-stage cervical cancer. Kaplan-Meier analysis of cervical cancer specimens also indicated an inverse relationship between the level of Eps8 and the patients' survival rate. Using small interfering RNA of eps8, we observed reduced proliferation and tumorigenesis in Eps8-attenuated HeLa and SiHa cells cultured in dishes or inoculated in mice. Furthermore, diminished Eps8 impeded G1-phase progression in HeLa and SiHa cells that might be attributable to reduced expression of cyclins D1, D3, and E, elevated accumulation of p53 and its downstream target p21Waf1/Cip1, and suppressed hyperphosphorylation of retinoblastoma. Alteration of these cell cycle–related proteins could be reversed by ectopic Eps8, implicating that the effect of Eps8 on the mentioned cell cycle modulators was specific. Notably, the augmented expression of p53 by diminished Eps8 was at least due to its decreased turnover rate. Concurrent with p53 up-regulation and the decrement of Src and AKT activity, Eps8-attenuated HeLa and SiHa cells exhibited increased chemosensitivity to cisplatin and paclitaxel. Together, our findings implicate the involvement of Eps8 in chemoresistance and show its importance in prognosis of cervical cancer patients. [Mol Cancer Ther 2008;7(6):1376–85]
Photodynamic therapy with an endocytically located photosensitizer cause a rapid activation of the mitogen-activated protein kinases extracellular signal-regulated kinase, p38, and c-Jun NH2 terminal kinase with opposing effects on cell survival
Authors: Weyergang Anette , Kaalhus Olav , Berg Kristian
Published: June 2008

Photochemical internalization (PCI) is a method for release of endosomally/lysosomally trapped drugs into the cell cytosol. PCI is based on photosensitizers that accumulate in the membranes of endosomes and lysosomes. Light exposure generates reactive oxygen species that cause membrane rupture and subsequently drug release. PCI can be considered as a combination therapy of photodynamic therapy (PDT) and the administrated drug. The present work reports on mitogen-activated protein kinase signaling after PDT with the endocytically located photosensitizer TPPS2a (meso-tetraphenylporphine with two sulfonate groups on adjacent phenyl rings) as used for PCI in two cancer cell lines: NuTu-19 and WiDr. Both extracellular signal-regulated kinase (ERK) and p38 were activated immediately after PDT. The photochemically induced ERK phosphorylation was enhanced by epidermal growth factor stimulation to a level above that obtainable with epidermal growth factor alone. Expression of the ERK phosphatase, MAPK phosphatase-1, was increased 2 h after PDT but was not the cause of ERK dephosphorylation observed simultaneously. A transient activation of c-Jun NH2 terminal kinase was also observed after PDT but only in the NuTu-19 cells. Using suitable inhibitors, it is shown here that the p38 signal is a death signal, whereas c-Jun NH2 terminal kinase rescues cells after PDT. No direct connection was observed between PDT-induced ERK activation and toxicity of the treatment. The present results document the importance of the mitogen-activated protein kinases in TPPS2a-PDT-induced cytotoxicity. [Mol Cancer Ther 2008;7(6):1740–50]
KD5170, a novel mercaptoketone-based histone deacetylase inhibitor, exerts antimyeloma effects by DNA damage and mitochondrial signaling
Authors: Feng Rentian , Ma Huihui , Hassig Christian A. , Payne Joseph E. , Smith Nicholas D. , Mapara Markus Y. , Hager Jeffrey H. , Lentzsch Suzanne
Published: June 2008

Histone deacetylase inhibitors have emerged as promising anticancer drugs. Using an unbiased ultrahigh throughput screening system, a novel mercaptoketone-based histone deacetylase inhibitor series was identified that was optimized to the lead compound, KD5170. KD5170 inhibited the proliferation of myeloma cell lines and the viability of CD138+ primary myeloma cells by induction of apoptosis, accompanied by an increase of acetylation of histones and activation of caspase-3, caspase-8, and caspase-9. Treatment with KD5170 caused a loss of mitochondrial membrane potential resulting in release of apoptogenic factors such as cytochrome c, Smac, and apoptosis-inducing factor. Furthermore, KD5170 induced oxidative stress and oxidative DNA damage in myeloma cells as evidenced by the up-regulation of heme oxygenase-1 and H2A.X phosphorylation. Combination of KD5170 with proteasome inhibitor bortezomib or tumor necrosis factor–related apoptosis-inducing ligand synergistically enhanced the antimyeloma activity. We further found that resistance of myeloma cells to KD5170 was associated with activation of the extracellular signal-regulated kinase/mitogen-activated protein kinase pathway under treatment with KD5170. Pretreatment with the mitogen-activated protein kinase inhibitor U0126 restored sensitivity to KD5170, suggesting that the combination of KD5170 with U0126 could overcome drug resistance. Growth of myeloma tumor xenografts in KD5170-treated nude mice was significantly inhibited and survival was prolonged. Histone acetylation was increased in spleen and tumor tissues of animals treated with KD5170. Our data indicate that KD5170 has potent antimyeloma activity in vitro and in vivo, which is mediated by DNA damage and mitochondrial signaling and subsequent induction of apoptosis. [Mol Cancer Ther 2008;7(6):1494–505]
Anticancer drugs affect the alternative splicing of Bcl-x and other human apoptotic genes
Authors: Shkreta Lulzim , Froehlich Ulrike , Paquet Éric R. , Toutant Johanne , Elela Sherif Abou , Chabot Benoit
Published: June 2008

Inducing an apoptotic response is the goal of most current chemotherapeutic interventions against cancer. However, little is known about the effect of chemotherapeutic agents on the alternative splicing of apoptotic genes. Here, we have tested 20 of the mainstream anticancer drugs for their ability to influence the production of Bcl-x splice isoforms. We find that many drugs shift splicing toward the proapoptotic Bcl-xS splice variant in 293 cells. The drugs modulate splicing decisions most likely through signaling events because the splicing switch is not compromised by inhibiting de novo protein synthesis or the activity of caspases. Several drugs also shift Bcl-x splicing in cancer cell lines (MCF-7, HeLa, PC-3, PA-1, and SKOV-3), but the set of active drugs varies between cell lines. We also examined the effect of anticancer agents on the alternative splicing of 95 other human apoptotic genes in different cell lines. Almost every drug can alter a subset of alternative splicing events in each cell line. Although drugs of the same class often influence the alternative splicing of the same units in individual cell lines, these units differ considerably between cell lines, indicating cell line–specific differences in the pathways that control splicing. [Mol Cancer Ther 2008;7(6):1398–409]
Anti-integrin monoclonal antibody CNTO 95 enhances the therapeutic efficacy of fractionated radiation therapy in vivo
Authors: Ning Shoucheng , Nemeth Jeffrey A. , Hanson Rebecca L. , Forsythe Kevin , Knox Susan J.
Published: June 2008

Selective targeting of up-regulated integrins on tumor cells is a novel antiangiogenesis strategy for treating solid tumors. CNTO 95 is a fully human anti-αv integrin monoclonal antibody and has shown antitumor activity when used as a single agent in preclinical studies. We previously showed that radiation combined with an integrin αvβ3 antagonist cRGD peptide increased the therapeutic efficacy of radiation in preclinical tumor models. We hypothesized that the combination of radiation and CNTO 95 would synergistically enhance the efficacy of radiation therapy. The in vitro studies showed that CNTO 95 radiosensitized and induced apoptosis in M21 cells in vitronectin-coated dishes. In mice bearing established human cancer xenograft tumors, CNTO 95 alone had only a moderate effect on tumor growth. The combined therapy of CNTO 95 and fractionated radiation significantly inhibited tumor growth and produced the longer tumor growth delay time in multiple tumor models. Maintenance dosing of CNTO 95 following irradiation contributed to efficacy and was important for continued inhibition of tumor regrowth. Immunohistochemistry studies showed that the combined use of CNTO 95 and radiation reduced the αv integrin and vascular endothelial growth factor receptor expression and the microvessel density and increased apoptosis in tumor cells and the tumor microenvironment. CNTO 95 alone and in combination with radiation did not produce any obvious signs of systemic toxicity. These results show that CNTO 95 can potentiate the efficacy of fractionated radiation therapy in a variety of human cancer xenograft tumor types in nude mice. These findings are very promising and may have high translational relevance for the treatment of patients with solid tumors. [Mol Cancer Ther 2008;7(6):1569–78]