bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of an Experimental Viscoelastic Food Model System for Studying
Zygosaccharomyces bailii
Spoilage in Acidic Sauces
Authors: Mertens L. , Geeraerd A. H. , Dang T. D. T. , Vermeulen A. , Serneels K. , Van Derlinden E. , Cappuyns A. M. , Moldenaers P. , Debevere J. , Devlieghere F. , Van Impe J. F.
Published: September 2009

Within the field of predictive microbiology, the number of studies that quantify the effect of food structure on microbial behavior is very limited. This is mainly due to impracticalities related to the use of a nonliquid growth medium. In this study, an experimental food model system for studying yeast spoilage in acid sauces was developed by selecting a suitable thickening/gelling agent. In a first step, a variety of thickening/gelling agents was screened, with respect to the main physicochemical (pH, water activity, and acetic acid and sugar concentrations) and rheological (weak gel viscoelastic behavior and presence of a yield stress) characteristics of acid sauces. Second, the rheological behavior of the selected thickening/gelling agent, Carbopol 980, was extensively studied within the following range of conditions: pH 4.0 to 5.0, acetic acid concentration of 0 to 1.0% (vol/vol), glycerol concentration of 0 to 15% (wt/vol), and Carbopol concentration of 1.0 to 1.5% (wt/vol). Finally, the applicability of the model system was illustrated by performing growth experiments in microtiter plates for
Zygosaccharomyces bailii
at 0, 0.5, 1.0, and 1.5% (wt/vol) Carbopol, 5% (wt/vol) glycerol, 0% (vol/vol) acetic acid, and pH 5.0. A shift from planktonic growth to growth in colonies was observed when the Carbopol concentration increased from 0.5 to 1.0%. The applicability of the model system was illustrated by estimating μ
max
at 0.5% Carbopol from absorbance detection times.
Promoter Strength Properties of the Complete Sigma E Regulon of
Escherichia coli
and
Salmonella enterica
Authors: Mutalik Vivek K. , Nonaka Gen , Ades Sarah E. , Rhodius Virgil A. , Gross Carol A.
Published: September 2009

The σ
E
-directed envelope stress response maintains outer membrane homeostasis and is an important virulence determinant upon host infection in
Escherichia coli
and related bacteria. σ
E
is activated by at least two distinct mechanisms: accumulation of outer membrane porin precursors and an increase in the alarmone ppGpp upon transition to stationary phase. Expression of the σ
E
regulon is driven from a suite of approximately 60 σ
E
-dependent promoters. Using green fluorescent protein fusions to each of these promoters, we dissected promoter contributions to the output of the regulon under a variety of in vivo conditions. We found that the σ
E
promoters exhibit a large dynamic range, with a few strong and many weak promoters. Interestingly, the strongest promoters control either transcriptional regulators or functions related to porin homeostasis, the very functions conserved among
E. coli
and its close relatives. We found that (i) the strength of most promoters is significantly affected by the presence of the upstream (−35 to −65) region of the promoter, which encompasses the UP element, a binding site for the C-terminal domain of the α-subunit of RNA polymerase; (ii) ppGpp generally activates σ
E
promoters, and (iii) σ
E
promoters are responsive to changing σ
E
holoenzyme levels under physiological conditions, reinforcing the idea that the σ
E
regulon is extremely dynamic, enabling cellular adaptation to a constantly changing environment.
Multiple Two-Component Systems of
Streptococcus mutans
Regulate Agmatine Deiminase Gene Expression and Stress Tolerance
Authors: Liu Yaling , Burne Robert A.
Published: September 2009

Induction of the agmatine deiminase system (AgDS) of
Streptococcus mutans
requires agmatine and is optimal at low pH. We show here that the VicRK, ComDE, and CiaRH two-component systems influence AgDS gene expression in response to acidic and thermal stresses.
The Low-Molecular-Weight Fraction of Exopolysaccharide II from
Sinorhizobium meliloti
Is a Crucial Determinant of Biofilm Formation
Authors: Rinaudi Luciana V. , González Juan E.
Published: September 2009

Sinorhizobium meliloti
is a soil bacterium that elicits the formation of root organs called nodules on its host plant,
Medicago sativa
. Inside these structures, the bacteria are able to convert atmospheric nitrogen into ammonia, which is then used by the plant as a nitrogen source. The synthesis by
S. meliloti
of at least one exopolysaccharide, succinoglycan or EPS II, is essential for a successful symbiosis. While exopolysaccharide-deficient mutants induce the formation of nodules, they fail to invade them, and as a result, no nitrogen fixation occurs. Interestingly, the low-molecular-weight fractions of these exopolysaccharides are the symbiotically active forms, and it has been suggested that they act as signals to the host plant to initiate infection thread formation. In this work, we explored the role of these rhizobial exopolysaccharides in biofilm formation and their importance in the symbiotic relationship with the host. We showed that the ExpR/Sin quorum-sensing system controls biofilm formation in
S. meliloti
through the production of EPS II, which provides the matrix for the development of structured and highly organized biofilms. Moreover, the presence of the low-molecular-weight fraction of EPS II is vital for biofilm formation, both in vitro and in vivo. This is the first report where the symbiotically active fraction of EPS II is shown to be a critical factor for biofilm formation and root colonization. Thus, the ability of
S. meliloti
to properly attach to root surfaces and form biofilms conferred by the synthesis of exopolysaccharides may embody the main function of these symbiotically essential molecules.
Death and organ donation: back to the future
Authors: Miller F G
Published: September 2009

The practice of transplantation of vital organs from “brain-dead” donors is in a state of theoretical disarray. Although the law and prevailing medical ethics treat patients diagnosed as having irreversible total brain failure as dead, scholars have increasingly challenged the established rationale for regarding these patients as dead. To understand the ethical situation that we now face, it is helpful to revisit the writings of the philosopher Hans Jonas, who forcefully challenged the emerging effort to redefine death in the late 1960s.
Smart drugs for cognitive enhancement: ethical and pragmatic considerations in the era of cosmetic neurology
Authors: Cakic V
Published: September 2009

Reports in the popular press suggest that smart drugs or “nootropics” such as methylphenidate, modafinil and piracetam are increasingly being used by the healthy to augment cognitive ability. Although current nootropics offer only modest improvements in cognitive performance, it appears likely that more effective compounds will be developed in the future and that their off-label use will increase. One sphere in which the use of these drugs may be commonplace is by healthy students within academia. This article reviews the ethical and pragmatic implications of nootropic use in academia by drawing parallels with issues relevant to the drugs in sport debate. It is often argued that performance-enhancing drugs should be prohibited because they create an uneven playing field. However, this appears dubious given that “unfair” advantages are already ubiquitous and generally tolerated by society. There are concerns that widespread use will indirectly coerce non-users also to employ nootropics in order to remain competitive. However, to restrict the autonomy of all people for fear that it may influence the actions of some is untenable. The use of potentially harmful drugs for the purposes of enhancement rather than treatment is often seen as unjustified, and libertarian approaches generally champion the rights of the individual in deciding if these risks are acceptable. Finally, whether the prohibition of nootropics can be effectively enforced is doubtful. As nootropics use becomes widespread among students in the future, discussion of this issue will become more pressing in the years to come.
Modulation ofCYP1B1andCYP1A1gene expression and activation of aryl hydrocarbon receptor byGinkgo bilobaextract in MCF-10A human mammary epithelial cells
Authors: Rajaraman Ganesh , Yang Guixiang , Chen Jie , Chang Thomas K.H.
Published: September 2009

The aryl hydrocarbon receptor (AhR) signaling pathway regulates the production of CYP1B1 and CYP1A1, which catalyze the bioactivation of various procarcinogens. In the present study, we investigated the effect of Ginkgo biloba extract and some of its chemical constituents on CYP1B1 and CYP1A1 gene expression and AhR activity in cultured MCF-10A human mammary epithelial cells. Treatment of MCF-10A cells with noncytotoxic concentrations of G. biloba extract (25–300 µg/mL for 24 or 48 h) increased CYP1B1 and CYP1A1 mRNA expression, which was accompanied by an increase in CYP1-mediated ethoxyresorufin O-dealkylation activity. The inductive effects of G. biloba extract were attenuated by an AhR antagonist (3′,4′-dimethoxyflavone). G. biloba extract (25–300 µg/mL) increased AhR-dependent reporter activity, as determined in MCF-10A cells transfected with an AhR-regulated luciferase reporter plasmid (pGudluc6.1). Bilobalide and ginkgolides A, B, C, and J were not responsible for the modulation of CYP1B1 and CYP1A1 gene expression or AhR activation by G. biloba extract. In contrast, quercetin increased CYP1B1 and CYP1A1 gene expression and activated AhR, whereas kaempferol and isorhamnetin suppressed constitutive CYP1B1 expression and antagonized AhR activation by benzo[a]pyrene. Overall, our findings provide an impetus for future investigations on the effect of G. biloba extract in CYP1-mediated chemical carcinogenesis.
Protective effect ofLycium barbarumpolysaccharide 4 on kidneys in streptozotocin-induced diabetic rats
Authors: Zhao Rui , Li Qing-wang , Li Jian , Zhang Tao
Published: September 2009

Lycium barbarum polysaccharide (LBP) has been shown to have hypoglycemic and antioxidative properties, although its mode of action is yet unknown. Because oxidative stress is implicated in the pathogenesis of diabetic nephropathy, we evaluated the protective effect of LBP-4, the major active component of Lycium barbarum, on the defensive antioxidative mechanism in kidneys in a streptozotocin-induced diabetic rat model. Moreover, we investigated the effects of LBP-4 on the activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) in isolated mesangial cells. The role of protein kinase C (PKC)-dependent and -independent pathways in LBP-4-reduced ERK1/2 was studied by bisindolylmaleimide (BIM) IV, an inhibitor of PKC. Diabetic rats treated with LBP-4 (10 mg/kg) for 8 weeks showed increased activity of antioxidant enzymes and increased scavenging of oxygen radicals, while the activity of PKC in the renal cortex was maintained at a physiological level. The decreased activation of ERK1/2 in mesangial cells, through the involvement of PKC, could explain the protective mechanism in kidneys of diabetic rats treated with LBP-4.
3,3′,4′,5,7-Pentamethylquercetin reduces angiotensin II-induced cardiac hypertrophy and apoptosis in rats
Authors: Mao Zhangfan , Liang Yuanxin , Du Xinling , Sun Zongquan
Published: September 2009

Quercetin has been shown to possess beneficial pharmacological properties in treatment of heart disease, but lack of stability and bioavailability limits its clinical use. In this study, we investigated for the first time the effect of a methylated form of quercetin, 3,3′,4′,5,7-pentamethylquercetin (PMQ), on myocardial protection in rats. Angiotensin II was delivered to Sprague–Dawley rats subcutaneously, while PMQ (5 mg/kg) was administered by oral gavage; blood pressure was monitored daily. The production of NADPH oxidase was measured, and cardiac hypertrophy and apoptosis were detected. The results revealed that PMQ could downregulate the expression of the NADPH oxidase gene and reduce angiotensin II- induced cardiac hypertrophy and apoptosis in rats. Therefore, we believe that PMQ showed beneficial effects on myocardium in angiotensin II-administered rats, and its potential to be used for treatment of cardiovascular disease deserves further attention.
Validation of spontaneous assessment of baroreceptor reflex sensitivity and its relation to heart rate variability in the ovine fetus pre- and near-term
Authors: Frasch Martin G. , Müller Thomas , Szynkaruk Mark , Schwab Matthias
Published: September 2009

Assessment of baroreceptor reflex sensitivity (BRS) in the ovine fetus provides insight into autonomic cardiovascular regulation. Currently, assessment of BRS relies on vasoactive drugs, but this approach is limited by feasibility issues and by the nonphysiologic nature of the stimulus. Thus we aimed to validate the method of spontaneous BRS assessment against the reference method of using vasoactive drugs in preterm (0.76 gestation, n = 16) and near-term (0.86 gestation, n = 16) chronically instrumented ovine fetuses. The BRS measures derived from the spontaneous and reference methods correlated at both gestational ages (R = 0.67 ± 0.03). The sequence method of spontaneous BRS measures also correlated both to the root mean square of standard deviations (RMSSD), which is a measure of fetal heart rate variability reflecting vagal modulation (R = 0.69 ± 0.03), and to fetal body weight (R = 0.65 ± 0.03), which is a surrogate for growth trajectory of each fetus. The methodology presented may aid in developing new models to study BRS and cardiovascular control in ovine fetus in the last trimester of pregnancy.
Effect of water temperature on laboratory swimming performance and natural activity levels of adult largemouth bass
Authors: Hasler Caleb T. , Suski Cory D. , Hanson Kyle C. , Cooke Steven J. , Philipp David P. , Tufts Bruce L.
Published: September 2009

Although locomotory performance in vertebrates is related to fitness, most performance tests are conducted in a laboratory setting, or in a manner that forces the organism to move not of their own volition. Biotelemetry offers the possibility to measure voluntary activity in a natural setting and provides the opportunity to combine laboratory-derived data with field studies on wild fish. In this study, it was found that laboratory- and field-based measurements of swimming performance and voluntary activity resulted in similar general seasonal trends, though each measurement assessed a different swimming type. In the field, all swimming metrics were lower at cooler water temperatures and were lowest during early winter (mean daily activity = 0.016 BL/s; mean voluntary swimming activity = 0.04319 BL/s; maximum swimming speed = 0.17 BL/s). In the laboratory, fish acclimatized to 25.0, 14.0, and 7.5 °C decreased swimming performance (Ucrit) with water temperature (25.0 °C (2.17 BL/s); 14.0 °C (1.69 BL/s); 7.5 °C (1.17 BL/s). Although some species and tissues have been shown to exhibit different degrees of thermal adaptation, these results show that swimming, one of the most important functions in fish, is largely dependent on environmental temperature, at least in largemouth bass ( Micropterus salmoides (Lacepède, 1802)).
Source levels and communication-range models for harp seal (Pagophilus groenlandicus) underwater calls in the Gulf of St. Lawrence, Canada
Authors: Rossong M. A. , Terhune J. M.
Published: September 2009

Harp seals ( Pagophilus groenlandicus (Erxleben, 1777)) produce underwater call types during the breeding season that are thought to be important for reproductive behaviours and herd formation. Underwater calls were recorded in the Gulf of St. Lawrence, Canada, in March 2007. A four hydrophone array system determined the locations of nearby calling seals and call source levels (amplitudes at 1 m from the seal). Source levels ranged from 103 to 180 dB re 1 µPa-m and mean values per call type ranged from 129 to 151 dB re 1 µPa-m with considerable overlap between call types. Short-range sound transmission losses under the ice were variable. Theoretical communication-range models were constructed under quiet (0 sea state, transmission-loss pattern of 20 log range) and noisy (herd noise, transmission-loss patterns of 15, 17.5, or 20 log range) conditions. Monte Carlo models for the calls for a quiet sea indicated median distances of 0.5–5.5 km (maximum 80 km). Communication distances in the presence of other calling seals dropped to 0.03–0.5 km (maximum 15 km) for dB loss = 20 log range but were longer under different spreading-loss patterns. Communication ranges are significantly influenced by call source levels, background noise, and in situ sound transmission patterns.
Genetic diversity in a remnant population of lake trout (Salvelinus namaycush)
Authors: Giroux Tina M.J. , Chivers Douglas P. , Fitzsimmons Michael J. , Chilton Neil B.
Published: September 2009

Genetic diversity of the remnant population of lake trout ( Salvelinus namaycush (Walbaum in Artedi, 1792)) in Crean Lake was compared with that for two other populations in the Prince Albert National Park (PANP) using single-strand conformation polymorphism (SSCP) and DNA sequencing analyses of two mtDNA genes. Although there was no sequence variation among individuals for nad5, six different nad2 haplotypes were detected. The Crean Lake population had the least number of haplotypes and lowest nucleotide variation. Also, one common nad2 haplotype in Crean Lake was not detected in the other populations. The results suggest that introductions of lake trout from Wassegam Lake into Crean Lake were unsuccessful with respect to the establishment and (or) reproduction of the stocked fish. Conservation of the remnant population of lake trout in Crean Lake is important because it is genetically distinct from other populations within PANP and in adjacent areas.
Holding ground in the face of invasion: native fence lizards (Sceloporus undulatus) do not alter their habitat use in response to introduced fire ants (Solenopsis invicta)
Authors: Langkilde T.
Published: September 2009

The introduction of non-native species is becoming increasingly common. Understanding the impact of invaders on native populations is critical for effective management. Red imported fire ants ( Solenopsis invicta Buren, 1972) were introduced to the USA in the 1930s. They will attack, and can kill, native fence lizards ( Sceloporus undulatus (Bosc and Daudin in Sonnini and Latreille, 1801)), which co-occur with these ants across much of their invasive range. I determined whether fence lizards minimize encounters with S. invicta by altering their habitat use following invasion or avoiding cues of the presence of these fire ants. I recorded the habitat use of fence lizards and S. invicta mounds across four sites with different histories of invasion, and quantified lizard avoidance of S. invicta scent. I found that lizards do not alter their habitat use following S. invicta invasion, nor do they spatially avoid their mounds. Fence lizards do avoid S. invicta scent, but this was only evident in naïve or recently invaded populations. The lack of avoidance of S. invicta by fence lizards could be explained by the high prevalence of these fire ants, making them difficult to avoid, and adaptive shifts in the escape behaviour and morphology of these lizards following invasion that permit them to survive fire ant attack.
Population genetics and social organization of the sperm whale (Physeter macrocephalus) in the Azores inferred by microsatellite analyses
Authors: Pinela A. M. , Quérouil S. , Magalhães S. , Silva M. A. , Prieto R. , Matos J. A. , Santos R. S.
Published: September 2009

In the northeast Atlantic Ocean, the archipelago of the Azores is frequented by female–offspring groups of sperm whales ( Physeter macrocephalus L., 1758), as well as large males. The Azores apparently constitute both a feeding ground and a reproduction site. Little is known about the population and group structure of sperm whales in the area. We analysed 151 sloughed skin and biopsy samples collected from 2002 to 2004. Molecular analyses involved genetic tagging using 11 microsatellite loci and molecular sexing. Our objectives were to determine the population genetic structure, compare relatedness within and between social groups, infer kinship, and estimate the age of males at dispersal. Results suggest that individuals visiting the archipelago of the Azores belong to a single population. High genetic diversity and absence of inbreeding suggest that the population is recovering from whaling. Individuals sampled in close association are highly related, as well as those observed in the same area on the same day, suggesting that secondary social groups (i.e., the union of primary social units) are largely but not exclusively composed of relatives. Probable mother–offspring and full-sibling pairs were identified. Age of males at dispersal was estimated at 16.6 years, which was well above previous estimates for this species.
Stable hydrogen isotope (δD) values in songbird nestlings: effects of diet, temperature, and body size
Authors: Betini Gustavo S. , Hobson Keith A. , Wassenaar Leonard I. , Norris D. Ryan
Published: September 2009

Stable hydrogen isotopes (δD) can be a powerful tool for estimating the large-scale movements of animals, but the cause and extent of isotopic variation within animal tissues remain poorly understood. Here, we simultaneously examined three hypotheses to explain δD variation in the blood (δDB) of nestling Tree Swallows ( Tachycineta bicolor (Vieillot, 1808)) from a single nest-box population in southern Ontario, Canada: (1) microgeographic and (or) temporal variation in δD of local diet, (2) potential evaporation of protium resulting from variation in nest-box temperature, and (3) differences in body size resulting in higher rates of water loss and isotope fractionation in larger birds. δDB ranged from –128‰ to –94‰, with a mean ± SD of –113‰ ± 7‰. Nest-box temperatures ranged from 21.5 to 38 °C immediately prior to blood collection. A general linear mixed-effects model explained 80% of the variation in δDB and provided evidence that δD values in prey, maximum temperature 1 day prior to blood collection, and body size were all significant predictors of δDB. Our results suggest that isotopic variation in individuals and local populations arises from a combination of physiological factors and local environmental variation. To gain a complete understanding of how δD values can be used to estimate animal movements, additional work is needed to determine how these factors influence other tissues, such as metabolically inert feathers, and animals of different age classes.
Temperature and site selection by Blanding’s Turtles (Emydoidea blandingii) during hibernation near the species’ northern range limit
Authors: Edge C. B. , Steinberg B. D. , Brooks R. J. , Litzgus J. D.
Published: September 2009

Many animals that live in northern climates enter a state of prolonged dormancy during winter. These animals possess a suite of physiological and behavioural adaptations that minimize threats to survival while overwintering. There are three major threats to overwintering survival: metabolic and respiratory acidosis, freezing, and predation. Selection of hibernation sites should minimize these threats. We monitored dissolved oxygen, water depth, and temperature at overwintering locations of Blanding’s Turtles ( Emydoidea blandingii (Holbrook, 1838)) and at stations located haphazardly in six different habitat types over two winters in Algonquin Park, Ontario, Canada. Water depth and dissolved oxygen in overwintering sites used by turtles were similar to those measured at haphazard stations. In contrast, estimated turtle body temperatures (~0 °C) were significantly lower and less variable than water temperatures measured at haphazard stations. These data and those reported elsewhere suggest that there are two alternatives for selection of suitable hibernacula by anoxia tolerant turtles. In areas where there is periodic access to aerial oxygen, turtles select sites where ice cover may not be present for the entire winter, but in areas where ice cover restricts access to air, turtles select sites where water temperatures are close to 0 °C.
Managerial Responses to Initial Market Reactions on Share Repurchases
Authors: Chen Hung-Kun , Chen Yan-Shing , Huang Chia-Wei , Wang Yanzhi
Published: September 2009

While most papers in finance literature investigate how the stock market reacts to announcements of corporate events, very few study the opposite, how namely, the manager responds to the information from outside investors. In this paper, we examine this issue, using open market share repurchases. Open market share repurchase offers flexibility for the manager to decide whether or not to buy back shares. Therefore, the manager may refer to the opinions of outside investors and make the decision, based on actual buyback activities. We propose learning, over-confidence and timing hypotheses to interpret the behavior of the managerial response to initial market reaction on the share repurchase announcement. Empirically, if a repurchase announcement abnormal return is low, then the manager tends to achieve the repurchase announced ratio by purchasing more shares. In addition, the investor will positively react to this repurchase in the long run. These empirical findings are consistent with the market timing hypothesis, which implies that managers know the true value of their firms better than the market at the moment of the share repurchase announcement.
A Bayesian Monte Carlo Markov Chain Method for Loss Models and Risk Measure Assessments
Authors: Hu Ling , Yang Yating
Published: September 2009

Natural disasters are also known as catastrophes with low frequency but high damages. Typhoons and floods are the major catastrophes which lead to gargantuan losses in Asia. Once a disaster occurs, a broad region will be affected and this will result in huge social loss. If issuers or governments use the wrong loss models or risk measure indexes to price the related insurance products, they will get an inaccurate price and thus be insolvent to the claims. Previous researches often use a Log-Normal distribution to model a catastrophic loss. This is not appropriate since the characteristics of a loss distribution have some empirical facts, including the positive skewness and the heavy-tailed properties. Recently, some studies (McNeil and Frey, 2000; Rootzen and Tajvidi, 2000; Thuring et al., 2008) also point out that using Log-Normal distribution to model a characteristic loss is not suitable. Therefore, we build a typhoon and flood loss model with higher order moments and estimate the parameters through a Bayesian Monte Carlo Markov Chain method. According to the Kolmogorov-Smirnov test, we find that the Pareto distribution is more adaptive for modeling the loss of typhoon and flood. Further, we evaluate different kinds of risk measure indexes through simulating and numerical analysis. It gives the beacon to issuers or governments when they want to issue the insurance products about typhoon and flood loss.
ON OPEN RECTANGLE-OF-INFLUENCE AND RECTANGULAR DUAL DRAWINGS OF PLANE GRAPHS
Authors: ZHANG HUAMING , VAIDYA MILIND
Published: September 2009

Irreducible triangulations are plane graphs with a quadrangular exterior face, triangular interior faces and no separating triangles. Fusy proposed a straight-line grid drawing algorithm for irreducible triangulations, whose grid size is asymptotically with high probability 11n/27 × 11n/27 up to an additive error of [Formula: see text]. Later on, Fusy generalized the idea to quadrangulations and obtained a straight-line grid drawing, whose grid size is asymptotically with high probability 13n/27 × 13n/27 up to an additive error of [Formula: see text]. In this paper, we first prove that the above two straight-line grid drawing algorithms for irreducible triangulations and quadrangulations actually produce open rectangle-of-influence drawings for them respectively. Therefore, the above mentioned straight-line grid drawing size bounds also hold for the open rectangle-of-influence drawings. These results improve previous known drawing sizes.

In the second part of the paper, we present another application of the results obtained by Fusy. We present a linear time algorithm for constructing a rectangular dual for a randomly generated irreducible triangulation with n vertices, one of its dimensions equals [Formula: see text] asymptotically with high probability, up to an additive error of [Formula: see text]. In addition, we prove that the one dimension tight bound for a rectangular dual of any irreducible triangulations with n vertices is (n + 1)/2.
PERFECTION IN R-PROCESSES
Authors: SHEA STEPHEN
Published: September 2009

R-processes are a new type of discrete stationary stochastic process. In this paper, we investigate the underlying structure of two special classes of r-processes. For each class, we will prove precisely when the associated multidigraph is perfect.
A NOTE ON 3-COLORABLE PLANE GRAPHS WITHOUT 5- AND 7-CYCLES
Authors: XU BAOGANG
Published: September 2009

In [1], Borodin et al. figured out a gap of [5], and gave a new proof with the similar technique. The purpose of this note is to fix the gap of [5] by slightly revising the definition of special faces, and adding a few lines of explanation in the original proofs of [5] (new added text are all in italic type).
POLYNOMIAL APPROXIMATION SCHEMES FOR THE MAX-MIN ALLOCATION PROBLEM UNDER A GRADE OF SERVICE PROVISION
Authors: LI JIANPING , LI WEIDONG , LI JIANBO
Published: September 2009

The max-min allocation problem under a grade of service provision is defined in the following model: given a set [Formula: see text] of m parallel machines and a set [Formula: see text] of n jobs, where machines and jobs are all entitled to different levels of grade of service (GoS), each job [Formula: see text] has its processing time pj and it can only be allocated to a machine Mi whose GoS level is no more than the GoS level the job Jj has. The goal is to allocate all jobs to m machines to maximize the minimum machine load among these m machines, where the machine load of Mi is the sum of the processing time of jobs executed on Mi. The best known approximation algorithm [4] to solve this problem produces an allocation in which the minimum machine completion time is at least Ω ( log log log m/ log log m) of the optimal value.

In this paper, we respectively present four approximation schemes to solve this problem and its two special versions: (1) a polynomial time approximation scheme (PTAS) with a running time [Formula: see text] for the general version, where ϵ > 0; (2) a PTAS and a fully polynomial time approximation scheme (FPTAS) with the running time O(n) for the version where the number m of machines is fixed; (3) a PTAS with the running time O(n) for the version where the number of GoS levels is bounded by k.
CLASSIFICATION OF NEAR-NORMAL SEQUENCES
Authors: ĐOKOVIĆ DRAGOMIR Ž.
Published: September 2009

We introduce a canonical form for near-normal sequences NN(n), and using it we enumerate the equivalence classes of such sequences for even n ≤ 30.
IDENTIFYING STEINER MINIMAL TREES ON FOUR POINTS IN SPACE
Authors: WENG J. F. , THOMAS D. A. , MAREELS I.
Published: September 2009

A Steiner minimal tree is a network with minimum length spanning a given set of points in space. There are several criteria for identifying the Steiner minimal tree on four points in the Euclidean plane. However, it has been proved that the length of the Steiner minimal tree on four points cannot be computed using radicals if the four points lie in Euclidean space. This unsolvability implies that it is unlikely that similar necessary and sufficient conditions exist in the spatial case. Hence, a problem arises: Is it possible to generalize the known planar criteria to space in the sense that they are sufficient to identify Steiner minimal trees on four points in space? This problem is investigated and some sufficient conditions are proved in this paper. These sufficient conditions can help us to solve the general Steiner tree problem on n(> 4) points in Euclidean space.
THE RAMSEY NUMBERS FOR STARS OF ODD ORDER VERSUS A WHEEL OF ORDER NINE
Authors: ZHANG YUNQING , CHENG T. C. EDWIN , CHEN YAOJUN
Published: September 2009

For two given graphs G1 and G2, the Ramsey number R(G1, G2) is the smallest positive integer n such that for any graph G of order n, either G contains G1 or the complement of G contains G2. Let Sn denote a star of order n and Wm a wheel of order m + 1. In this paper we show that R(Sn, W8) = 2n + 1 for n ≥ 5 and n ≡ 1 (mod 2).
Attenuation of diabetes-induced renal dysfunction by multiple exposures to low-dose radiation is associated with the suppression of systemic and renal inflammation
Authors: Zhang Chi , Tan Yi , Guo Weiying , Li Cai , Ji Shunzi , Li Xiaokun , Cai Lu
Published: September 2009

Renal protection against diabetes-induced pathogenic injuries by multiple exposures to low-dose radiation (LDR) was investigated to develop a novel approach to the prevention of renal disease for diabetic subjects. C57BL/6J mice were given multiple low-dose streptozotocin (STZ; 60 × 6 mg/kg) to produce a type 1 diabetes. Two weeks after diabetes onset, some of diabetic mice and age-matched nondiabetic mice were exposed whole body to 25 mGy X-rays every other day for 2, 4, 8, 12, and 16 wk. Diabetes caused a significant renal dysfunction, shown by time-dependent increase in urinary microalbumin (Malb) and decrease in urinary creatinine (Cre), and pathological changes, shown by significant increases in renal structural changes and PAS-positive staining. However, diabetes-induced renal dysfunction and pathological changes were significantly, albeit partially, attenuated by multiple exposures to LDR. Furthermore, LDR protection against diabetes-induced renal dysfunction and pathological changes was associated with a significant suppression of diabetes-increased systemic and renal inflammation, shown by significant increases in serum and renal TNFα, ICAM-1, IL-18, MCP-1, and PAI-1 contents. To further explore the mechanism by which LDR prevents diabetes-induced renal pathological changes, renal oxidative damage was examined by Western blotting and immunohistochemical staining for 3-nitrotyrosine and 4-hydroxynonenal. Significant increase in oxidative damage was observed in diabetic mice, but not diabetic mice, with LDR. Renal fibrosis, examined by Western blotting of connective tissue growth factor and Masson's trichrome staining, was also evident in the kidneys of diabetic mice but not diabetic mice with LDR. These results suggest that multiple exposures to LDR significantly suppress diabetes-induced systemic and renal inflammatory response and renal oxidative damage, resulting in a prevention of the renal dysfunction and fibrosis.
Role of nitric oxide as a key mediator on cardiovascular actions of atrial natriuretic peptide in spontaneously hypertensive rats
Authors: Costa María A. , Elesgaray Rosana , Caniffi Carolina , Fellet Andrea , Mac Laughlin Myriam , Arranz Cristina
Published: September 2009

The objective was to study atrial natriuretic peptide (ANP) effects on mean arterial pressure (MAP) and cardiovascular nitric oxide (NO) system in spontaneously hypertensive rats (SHRs), investigating the receptors and signaling pathways involved. In vivo, SHRs and Wistar-Kyoto (WKY) rats were infused with saline (0.05 ml/min) or ANP (0.2 μg·kg−1·min−1) for 1 h. MAP and nitrites and nitrates excretion (NOx) were determined. NO synthase (NOS) activity and endothelial (eNOS), neuronal (nNOS) and inducible (iNOS) NOS expression were measured in the heart and aorta. In vitro, heart and aortic NOS activity induced by ANP was determined in the presence of iNOS and nNOS inhibitors, natriuretic peptide receptor (NPR)-A/B blocker, Giprotein, and calmodulin inhibitors. As a result, ANP diminished MAP and increased NOx in both groups. Cardiovascular NOS activity was higher in SHRs than in WKY rats. ANP increased NOS activity, but the activation was lower in SHRs than in WKY rats. ANP had no effect on NOS isoform expression. NOS activity induced by ANP was not modified by iNOS and nNOS inhibitors. NPR-A/B blockade blunted NOS stimulation via ANP in ventricle and aorta but not in atria. Cardiovascular NOS response to ANP was reduced by Giprotein and calmodulin inhibitors in both groups. In conclusion, in atria, ventricle, and aorta, ANP interacts with NPR-C receptors, activating Ca2+-calmodulin eNOS through Giprotein. In ventricle and aorta, NOS activation also involves NPR-A/B. The NOS response to ANP was impaired in heart and aorta of SHRs. The impaired NO-system response to ANP in hypertensive animals, involving alterations in the signaling pathway, could participate in the maintenance of high blood pressure in this model of hypertension.
Effects of postural changes and removal of vestibular inputs on blood flow to and from the hindlimb of conscious felines
Authors: Yavorcik K. J. , Reighard D. A. , Misra S. P. , Cotter L. A. , Cass S. P. , Wilson T. D. , Yates B. J.
Published: September 2009

Considerable data show that the vestibular system contributes to blood pressure regulation. Prior studies reported that lesions that eliminate inputs from the inner ears attenuate the vasoconstriction that ordinarily occurs in the hindlimbs of conscious cats during head-up rotations. These data led to the hypothesis that labyrinthine-deficient animals would experience considerable lower body blood pooling during head-up postural alterations. The present study tested this hypothesis by comparing blood flow though the femoral artery and vein of conscious cats during 20–60° head-up tilts from the prone position before and after removal of vestibular inputs. In vestibular-intact animals, venous return from the hindlimb dropped considerably at the onset of head-up tilts and, at 5 s after the initiation of 60° rotations, was 66% lower than when the animals were prone. However, after the animals were maintained in the head-up position for another 15 s, venous return was just 33% lower than before the tilt commenced. At the same time point, arterial inflow to the limb had decreased 32% from baseline, such that the decrease in blood flow out of the limb due to the force of gravity was precisely matched by a reduction in blood reaching the limb. After vestibular lesions, the decline in femoral artery blood flow that ordinarily occurs during head-up tilts was attenuated, such that more blood flowed into the leg. Contrary to expectations, in most animals, venous return was facilitated, such that no more blood accumulated in the hindlimb than when labyrinthine signals were present. These data show that peripheral blood pooling is unlikely to account for the fluctuations in blood pressure that can occur during postural changes of animals lacking inputs from the inner ear. Instead, alterations in total peripheral resistance following vestibular dysfunction could affect the regulation of blood pressure.
Low-dose indomethacin after ischemic acute kidney injury prevents downregulation of Oat1/3 and improves renal outcome
Authors: Schneider R. , Meusel M. , Renker S. , Bauer C. , Holzinger H. , Roeder M. , Wanner C. , Gekle M. , Sauvant C.
Published: September 2009

We have previously shown that expression of renal organic anion transporters Oat1 and Oat3 is diminished by prostaglandin E2 (PGE2) and that both transporters are downregulated after renal ischemia. Because PGE2 is increased after renal ischemia and is generated by cyclooxygenases (COX), we investigated the effect of the COX inhibitor indomethacin on expression of Oat1/3 after ischemic acute kidney injury (iAKI). iAKI was induced in rats by bilateral clamping of renal arteries for 45 min. Indomethacin (1 mg/kg) was given intraperitoneally as soon as reperfusion started. Sham-treated animals served as controls. Oat1/3 were determined by qPCR and Western blot. PGE2 in blood and urine was measured by enzyme-linked immunosorbent assay. Invasion of monocytes/macrophages was determined. Glomerular filtration rate and renal plasma flow were determined. All parameters were detected 24 h after ischemia. PAH net secretion, as well as clearance and secretion of PGE2 were calculated. In clamped animals, indomethacin restored expression of Oat1/3, as well as PAH net secretion, PGE2 clearance, or PGE2 secretion. Additionally, indomethacin substantially improved kidney function as measured by glomerular filtration and PAH clearance. Indomethacin did not affect ischemia-induced invasion of monocytes/macrophages. In conclusion, our study indicates that low-dose indomethacin applied after ischemia prevents ischemia-induced downregulation of Oat1/3 during reperfusion and has a substantial protective effect on kidney function after iAKI. The beneficial effect of low-dose indomethacin on renal outcome is likely due to an effect different from inhibition of inflammation. In accordance to the decreased PAH net secretion, renal excretion of an endogenous organic anion (PGE2) is also impaired after ischemia and reperfusion.
Overlapping Prediction Errors in Dorsal Striatum During Instrumental Learning With Juice and Money Reward in the Human Brain
Authors: Valentin Vivian V. , O'Doherty John P.
Published: September 2009

Prediction error signals have been reported in human imaging studies in target areas of dopamine neurons such as ventral and dorsal striatum during learning with many different types of reinforcers. However, a key question that has yet to be addressed is whether prediction error signals recruit distinct or overlapping regions of striatum and elsewhere during learning with different types of reward. To address this, we scanned 17 healthy subjects with functional magnetic resonance imaging while they chose actions to obtain either a pleasant juice reward (1 ml apple juice), or a monetary gain (5 cents) and applied a computational reinforcement learning model to subjects' behavioral and imaging data. Evidence for an overlapping prediction error signal during learning with juice and money rewards was found in a region of dorsal striatum (caudate nucleus), while prediction error signals in a subregion of ventral striatum were significantly stronger during learning with money but not juice reward. These results provide evidence for partially overlapping reward prediction signals for different types of appetitive reinforcers within the striatum, a finding with important implications for understanding the nature of associative encoding in the striatum as a function of reinforcer type.
Tumor Apoptotic Bodies Inhibit CTL Responses and Antitumor Immunity via Membrane-Bound Transforming Growth Factor-β1 Inducing CD8+ T-Cell Anergy and CD4+ Tr1 Cell Responses
Authors: Xie Yufeng , Bai Ou , Yuan Jinying , Chibbar Rajni , Slattery Karen , Wei Yangdou , Deng Yulin , Xiang Jim
Published: September 2009

Tumor cell apoptosis induced by radiation therapy results in apoptotic tumor cells and apparition of membrane blebs termed apoptotic bodies (APB). The immune responses induced by apoptotic tumor cells have been extensively studied. However, the role of APB in modulation of tumor immune responses is elusive. In this study, we induced apoptosis in 90% ovabumin-expressing EG7 tumor cells by in vitro irradiation (9,000 rad) of tumor cells with a subsequent cell culture for 9 hours. APB purified from irradiation-induced apoptotic EG7 cell culture supernatant by differential ultracentrifugation were vesicles with 50 to 90 nm in diameter and expressed apoptosis-specific Annexin V, 14-3-3, and Histone H3. We then investigated its potential modulation in DCOVA–induced T-cell responses and antitumor immunity. We found that EG7-derived APB were tolerogenic and capable of suppressing DCOVA-stimulated CD8+ CTL responses and antitumor immunity via its induction of CD8+ T-cell anergy and type 1 regulatory CD4+ T-cell responses. Analysis of apoptotic tumor cells and APB revealed the expression of membrane-bound transforming growth factor (TGF)-β1 associated with irradiation-induced apoptosis formation, which is a result from activation of transcriptional factor NF-AT specific for TGF-β1 promoters. Our data further elucidate that it is the membrane-bound TGF-β1 expression on APB that contributes to its in vitro antiproliferative effect as shown by using neutralizing TGF-β1–specific antibody. Administration of anti–TGF-β1 antibody in vivo also blocked APB-mediated immune suppression of CD8+ CTL responses and antitumor immunity. Therefore, our study may have great impact in designing a combined radiation therapy with immunotherapy of cancer. [Cancer Res 2009;69(19):7756–66]
Vascular Adhesion Protein-1 Enhances Tumor Growth by Supporting Recruitment of Gr-1+CD11b+ Myeloid Cells into Tumors
Authors: Marttila-Ichihara Fumiko , Auvinen Kaisa , Elima Kati , Jalkanen Sirpa , Salmi Marko
Published: September 2009

Cancer growth is regulated by several nonmalignant cell types, such as leukocytes and endothelial cells, which reside in the stroma of the tumor. Vascular adhesion protein-1 (VAP-1) is an amine oxidase enzyme that is expressed on the surface of endothelial cells. It supports leukocyte traffic into inflamed tissues, but nothing is known about its possible role in cancer biology in vivo. Here, we report that B16 melanoma and EL-4 lymphoma remain smaller in VAP-1–deficient mice than in wild-type controls. We found an unexpected defect in tumor angiogenesis in the absence of VAP-1. VAP-1 also selectively enhanced the recruitment of Gr-1+CD11b+ myeloid cells into the tumors. Generation of mice expressing enzymatically inactive VAP-1 showed that the oxidase activity of VAP-1 was necessary to support neoangiogenesis, myeloid cell recruitment, and tumor growth in vivo. These data describe VAP-1 as the first adhesion molecule known to be involved in the recruitment of Gr-1+CD11b+ myeloid cells into tumors. They also suggest that VAP-1 is a potential new tool for immunotherapy of tumors that could be exploited to reduce tumor burden by controlling the traffic of Gr-1+CD11b+ myeloid cells. [Cancer Res 2009;69(19):7875–83]
Overexpression of Kinesins Mediates Docetaxel Resistance in Breast Cancer Cells
Authors: De Sarmishtha , Cipriano Rocky , Jackson Mark W. , Stark George R.
Published: September 2009

Resistance to chemotherapy remains a major barrier to the successful treatment of cancer. To understand mechanisms underlying docetaxel resistance in breast cancer, we used an insertional mutagenesis strategy to identify proteins whose overexpression confers resistance. A strong promoter was inserted approximately randomly into the genomes of tumor-derived breast cancer cells, using a novel lentiviral vector. We isolated a docetaxel-resistant clone in which the level of the kinesin KIFC3 was elevated. When KIFC3 or the additional kinesins KIFC1, KIF1A, or KIF5A were overexpressed in the breast cancer cell lines MDA-MB231 and MDA-MB 468, the cells became more resistant to docetaxel. The binding of kinesins to microtubules opposes the stabilizing effect of docetaxel that prevents cytokinesis and leads to apoptosis. Our finding that kinesins can mediate docetaxel resistance might lead to novel therapeutic approaches in which kinesin inhibitors are paired with taxanes. [Cancer Res 2009;69(20):8035–42]