bluuebunny/crossref_metadata_2025 huggingface dataset:
A comparison of protein crystal subunit sizes in Bacillus thuringiensis
Authors: Calabrese Diane M. , Nickerson Kenneth W. , Lane Leslie C.
Published: May 2010

We have employed gel electrophoresis to determine the number and size of the subunits present in the protein crystals from 16 strains of Bacillus thuringiensis. The calculated molecular weights (MW) fell into three major categories whose crystals exhibited the following protein banding patterns: type I, high MW only (140 000 – 160 000); type II, both high MW and medium MW (60 000 and 150 000); and type III, low MW only (40 000 – 50 000). Interestingly, the type I and type II crystals were the expected bipyramidal diamonds whereas the type III crystals possessed a previously unreported tetrahedral shape.
Exclusive formation of all-trans-phytoene by a colorless mutant of Halobacterium halobium
Authors: Kushwaha S. C. , Kates M. , Weber H. J.
Published: May 2010

A spontaneously occurring Halobacterium halobium mutant (strain W5002-1) was isolated which accumulated phytoene as the only C40 polyene. Its configuration was established as all-trans (7,8,11,12,7′,8′, 11′, 12′,-octahydro-ψ,ψ-carotene) by its chromatographic and spectral properties. Neither bacterioruberins (C50) nor retinal (C20) could be detected in this mutant strain. The biosynthetic pattern of isoprenoid compounds in this mutant strain confirms for the first time our conjecture that spontaneously arising H. halobium mutants can be isolated with defects in the carotenoid pathway and lends further support to our previous hypothesis suggesting all-trans-phytoene to be the precursor for more unsaturated carotenoids in halobacteria.
Partial characterization of Pseudomonas phage 2 receptor
Authors: Castillo Francisco J.
Published: May 2010

The lipopolysacharide from Pseudomonas aeruginosa strain B1 contains the receptors for phage 2 and strongly inactivates this phage in vitro (95–98% within 15 min).Several mono- and di-saccharides tested reduced phage 2 inactivation to 50% when present at the following concentrations: D-glucosamine, 0.25 M; maltose, 0.3 M; lactose and cellobiose, 0.5 M; D-glucose, L-rhamnose, D-mannose, 2-deoxy-D-glucose, and sucrose, 1.0 M; D-galactose, D-xylose, and N-acetyl-D-glucosamine, 1.4 M; and melibiose, > 1.6 M.These results suggest the possibility that phage 2 receptors in lipopolysaccharide contain L-rhamnose, D-glucosamine, and (or) D-glucose, or a structurally related molecule. Either one of the latter two could be located at a terminal position alpha-linked to the adjacent residue, or located internally in the polysaccharide chain linked through its C-4 position.
Protease production by fermentation of fish solubles from salmon canning processes
Authors: Wah-On H. C. , Branion R. M. R. , Strasdine G. A.
Published: May 2010

Production of protease by fermentation, using Sorangium 495, of a substrate based on condensed fish solubles is demonstrated. The effects of carbohydrate addition, pH, fish solubles concentration, scale-up, agitation, and air flow rate on protease yields are described. While the fish solubles medium alone could give rise to measurable yields of protease, these were, at worst, doubled when 1% glucose was added to the medium. pH 7 was optimal for protease yield. Although the concentration of fish solubles in the basic medium showed no significant effect on cell yield, maximum protease yield was observed at a protein concentration equivalent to 3.85 mg/mL of bovine serum albumin. Protease production rates decreased as medium protein concentration increased. Scale-up from 100 mL in shake flasks to 4 L in a stirred, sparged fermentor showed no significant effect on maximum protease yields. The effects of agitator speed and air flow rate on protease yield suggested that the rate of O2 transfer from air to medium could limit the rate of protease production. It was also noted that protease production is not growth associated.
Trypanosoma musculi: transfer of immunity from mother mice to litter
Authors: Brenière Simone , Viens Pierre
Published: May 2010

Trypanosoma musculi infection in newborn and young CBA/J mice lasted longer and produced higher parasitemia than in adult mice. IgM, followed by IgG1 and IgG2 antibodies, appeared after 2 weeks following infection of 8-day-old mice. Baby mice that recovered from infection were immune. Mice born to normal mothers and nursed by immune ones were completely protected for approximately 1 month. Antibodies of the IgM, IgG1, and IgG2 classes were found in sera of lactating mice. Immune resistance of baby mice did not correlate with the amount of antibodies transferred from the mother either before or after birth.
Homologous serological analysis of Rhizobium meliloti strains by immunodiffusion
Authors: Sinha R. C. , Peterson E. A.
Published: May 2010

The homologous titers of antisera prepared against 24 Rhizobium meliloti strains ranged from 8 to 64 in immunodiffusion tests when intact cells were used as test antigens. The antisera titers against a number of strains were higher when heated or ultrasonicated cell preparations were used as sources of antigens. The minimum concentration of intact cells required to produce a positive reaction varied between strains and the heat treatment of the cells of some strains increased the detectability of surface antigens. Titers of antigens in sonicated preparations of several strains were higher than those of either intact or heated cells. The minimum concentration of antigens detectable for different strains was independent of the antisera titers. Serological reactions of strains using intact cells were categorized in several groups based on the shape, position, and number of precipitin bands formed at different cell densities. The sonicated cell preparations produced additional bands and most strains contained both heat-stable and heat-labile antigens in such preparations. Some of these antigens were similar but not identical to the surface antigens whereas others appeared to be unrelated.
A survey of Clostridium perfringens enterotoxin antibody in human and animal sera in western Canada
Authors: Niilo L. , Bainborough A. R.
Published: May 2010

Sera from human, cattle, sheep, swine, and horse populations in western Canada were tested for the presence of Clostridium perfringens enterotoxin antibody by the passive hemagglutination (PHA) test, supplemented by an immunodiffusion test and by counterimmunoelectrophoresis. A total of 224 human, 345 cattle, 165 sheep, 620 swine, and 768 horse serum samples were examined. Low-titer reactions in the PHA test were detected in human, cattle, horse, and swine sera, in that order, with no titers demonstrated in sheep. The titers in human sera ranged up to 1:128 and three of these samples were also positive in the other two serological tests.The significance of this antibody is not clear, but it is suggested that the low prevalence of the antibody may reflect a low prevalence of enterotoxigenic C. perfringens strains in western Canada. Such serological surveys may be applicable to epidemiological studies involving enterotoxigenic C. perfringens.
Hybridization studies within the genus Schwanniomyces Klöcker
Authors: Johannsen Elżbieta , Walt J. P. Van der
Published: May 2010

Hybridization studies based on the prototrophic selection technique involving the use of auxotrophic mutants of seven Schwanniomyces strains are reported.Recombinant formation was not detected in any of the 87 experiments comprising both intrastrain and interstrain crosses of strains previously identified as S. alluvius, S. castellii, S. occidentalis, and S. persoonii.
Pedigreed stocks of Mycobacterium lepraemurium for cultivation and metabolic studies
Authors: Dhople Arvind M. , Hanks John H.
Published: May 2010

Experience has shown that a prime requirement for investigations with Mycobacterium lepraemurium is pedigreed stocks of cells which provide constant baselines over a long period of time. Biochemical indicator, ATP, was employed to devise a method for preservation of metabolic pools of M. lepraemurium during storage. ATP assays were made by the luciferin–luciferase bioluminescent method. Several cryoprotective agents were compared at −76 and 4 °C. The essential steps have been found to be (i) for prolonged storage and constant supply of material, to freeze the intracellular bacteria within infected cells containing 28% proteins, i.e., to freeze the infected tissue; and (ii) when a large number of diverse experiments are to be undertaken on a single suspension, to stabilize working stocks of refrigerated cells for 12–16 weeks by using bovine serum albumin, fraction V, and Difco yeast supplement B to compensate for the leaching of intracellular cofactors, metabolites, nucleotides, etc.
Effect of 3-O-methyl-D-glucose on the production of glycosidases by Cryptococcus laurentii and Saccharomyces cerevisiae
Authors: Bhanot Pradeep , Brown Robert G.
Published: May 2010

3-O-Methyl-D-glucose (3-O-MeGlc) or a mixture of 3-O-MeGlc and glucose stimulate invertase, β-glucosidase, α-glucosidase, and α-galactosidase production by Cryptococcus laurentii. They also increase invertase and α-glucosidase production by Saccharomyces cerevisiae. The stimulatory effect of 3-O-MeGlc is not caused by competition with glucose for transport nor by a direct action on glycosidases. It is proposed that 3-O-MeGlc acts as a structural rather than as a functional analogue of glucose displacing it from regulatory sites to relieve catabolite repression. Evidence is presented suggesting that intracellular cAMP levels may be related to the effect of 3-O-MeGlc.
Comparison of selective media for the enumeration and identification of fecal streptococci from natural sources
Authors: Pagel J. E. , Hardy G. M.
Published: May 2010

Five media and procedures were compared for their recovery of fecal streptococci on membrane filters. Growth and numbers of a variety of pure cultures were compared, and recoveries from raw sewage and sewage effluent were determined on the five media. A total of 512 isolates were identified and the specificity of each medium was determined from these results. While KF agar recovered significantly higher numbers of organisms, only 81% of the positive colonies were fecal streptococci. Slanetz and Bartley (SB) medium showed similarly low specificity and the mE procedure gave low recoveries. Best overall results were obtained on mEnterococcus (mEnt) agar with high (91%) specificity for enterococci, and very good recovery efficiency with low background counts. This medium was also the only one demonstrating any appreciable recovery of other fecal streptococci with 93% of the background colonies being confirmed as fecal streptococci of which most were Streptococcus bovis, S. equinus, or S. salivarius. Pfizer selective enterococcus (PSE) agar was second in overall performance with a high (94%) rate of specificity but this medium had lower recovery efficiency and high background counts. Performance of PSE agar could be considerably improved, without impairing specificity, by using a total count disregarding esculin hydrolysis.
Ethylene production by ectomycorrhizal fungi, Fusarium oxysporum f. sp. pini, and by aseptically synthesized ectomycorrhizae and Fusarium-infected Douglas-fir roots
Authors: Graham J. H. , Linderman R. G.
Published: May 2010

The ectomycorrhizal fungi Cenococcum geophilum, Hebeloma crustuliniforme, and Laccaria laccata produced ethylene in vitro in modified Melin–Norkrans liquid medium only if amended with 2.5–10 mM methionine; Pisolilhus tinctorius failed to produce ethylene unless the cultures were renewed with fresh methionine-amended medium before ethylene assay. An additional 19 ectomycorrhizal fungi, plus five isolates of Fusarium oxysporum f. sp. pini, all produced ethylene in renewed and (or) nonrenewed media. Although the rates varied, ethylene production by many ectomycorrhizal fungi equaled that of Fusarium.Culture filtrates of H, crustuliniforme and L. laccata also evolved ethylene that was apparently of nonenzymatic origin.Ethylene was produced by aseptically grown Douglas-fir seedlings inoculated with C. geophilum, H. crustuliniforme, and L. laccata and appearance of ethylene coincided with the formation of mycorrhizae; production by P. tinctorius inoculated seedlings was inconsistent. Lateral root formation of Douglas-fir was stimulated by inoculation with C. geophilum, H. crustuliniforme, and L. laccata but was inhibited by P. tinctorius. Fusarium-inoculated seedlings produced more ethylene sooner than seedlings inoculated with mycorrhizal fungi. The disparity in the levels of ethylene associated with ectomycorrhiza formation compared with Fusarium infection suggests a possible differential role for ethylene in symbiotic and pathogenic fungus–host interactions.
Regulation of primary alkylsulfatase induction in Pseudomonas C12B: concentration-dependent stimulation–inhibition by exogenous UTP and sodium acetate and inhibition by 1-hexanol
Authors: Fitzgerald John W. , Stewart Gregory J. , Kight-Olliff Lynda
Published: May 2010

Pseudomonas C12B, an isolate from detergent-enriched soil, synthesized primary alkylsulfatase in response to sodium hexan-1-yl sulfate as the inducer. The induction of this enzyme was inhibited by exogenous 1 mM UTP but not by ATP or other nucleoside triphosphates. The uridine nucleotide was about 10-fold more effective than other uracil-related effectors and the ability of the nucleotide (0.1–1.0 mM) to inhibit induction was dependent upon the presence of added Mg2+. At concentrations <0.1 mM, UTP stimulated induction and the extent of this effect was also Mg2+ dependent. Marked stimulation of induction also occurred in response to low (≤ 2.5 mM) concentrations of acetate, citrate, and succinate. However, only acetate inhibited induction (by 64%) at higher (20 mM) concentrations. 1-Hexanol was a more effective inhibitor. An 80% reduction in activity was recorded after exposure of cells to 5 mM 1-hexanol. At this concentration, 2-hexanol was without effect and 3-hexanol inhibited induction by 35%. Simultaneous exposure of the cells to 2,4-dinitrophenol failed to reverse hexanol- or acetate-mediated inhibition. It is suggested that 1-hexanol per se regulates alkylsylfatase induction and immediate product inhibition was proposed as a term to describe this type of inhibition.
The complete neuraminidase of influenza A/PR8/34 (H0N1) is not detectable in its recombinant virus
Authors: Arora D. J. S. , Hill-Schubert J.
Published: May 2010

The neuraminidase located on the influenza virus recombinant A/Eq (Heql) × A/PR8 (N1) was relatively a poor antigen (N1 titre < 10) as compared with the enzyme present on the parent virus A/PR8/34 (H0N1) (N1 titre 160). This difference in the antigenic behavior of the neuraminidase of A/PR8/34 (H0N1) virus was explored. Results obtained showed that rabbit anti-A/PR8/34 (H0N1) serum contained two distinct types of antineuraminidase antibody and only one type of antineuraminidase antibody was precipitable by the neuraminidase located on the recombinant virus. Evidence suggests that the parent enzyme(s) is not detectable in its entirety on its recombinant virus.
ON THE PROXIMITY OF WEIGHTED AND EXPONENTIAL DISTRIBUTIONS
Authors: OLUYEDE BRODERICK O.
Published: May 2010

In this paper stochastic relations and closure results for weighted and transformed distributions including the proportional hazards model are presented. Exponential approximations to the class of increasing failure rate (IFR) and decreasing failure rate (DFR) weighted distributions including transformed distributions with monotone weight functions are obtained. These include approximations via the proportional hazards and length-biased exponential distributions. Also, bounds and moment-type inequalities for weighted life distributions including proportional hazards models and some applications are presented.
ANALYSIS OF SEQUENTIAL MONITORING SCHEMES USING NATURAL CONJUGATE PRIORS
Authors: OKOGBAA O. GEOFFREY , DEVARAKONDA LAKSHMI , OTIENO WILKISTAR , ALBINO VITO
Published: May 2010

The complexity of modern manufacturing underscores the need for improved control strategies for these systems. We formulate a Bayesian attribute sequential monitoring plan useful for adaptive control of a production process. The Bayesian framework is based on natural informative conjugate priors that provide an optimal adjustment interval k in response to real-time changes in the operating characteristics of a process. The sampling and adjustment decisions are based on the tradeoffs between quality costs and quality parameters resulting from the process. The parameters include the fraction of nonconforming products p, and the number of nonconforming products r. The quality costs, which include the inspection, cost, repair cost, nonconformance cost, and adjustment cost are fixed and used to develop a breakeven relationship that that results in a sequential sampling construct that optimizes both the systems costs and process quality.
DIABETIC INTERSTITIAL GLUCOSE IN THE SKIN TISSUE BY ATR-FTIR SPECTROSCOPY VERSUS CAPILLARY BLOOD GLUCOSE
Authors: EIKJE NATALJA SKREBOVA
Published: May 2010

Recently introduced horizontal attenuated total reflectance (HATR) Fourier transform infrared (FTIR) spectroscopy for real-time assessment and continuous monitoring of glucose biomolecules in the skin tissue directly on the patients might appear a promising alternative to interpret the activity of interstitial glucose metabolism in vivo by means of evaluating the dynamics of changes of glucose concentrations in interstitial fluid (IF). In the present study, in vivo spectra by ATR-FTIR spectroscopy were obtained post-prandially during a 120–180-minute continuous monitoring in three patients with type 2 diabetes and compared to pre-prandial spectra. In all patients with diabetes interstitial glucose levels at 1030 and 1041 cm-1 reflected the best relationship with blood glucose. The lag time (LT) required for glucose to diffuse from the capillary to epidermal skin tissue was calculated between 0 and 60 minutes at all measured glucose biomolecules. Data showed intra- and inter-subject variations of each glucose biomolecule, pointing to similarities and differences among interstitial glucose metabolism of the patients. Finally, the findings suggest that HATR-FTIR spectroscopy might have the potential for clinical interpretation of activity of glucose metabolism for diagnosis, management, and treatment of patients with diabetes.
ACCURATELY DETERMINING PROPAGATION VELOCITY OF CORTICAL SPREADING DEPRESSION IN RATS BY OPTICAL INTRINSIC SIGNAL IMAGING
Authors: SUN XIAOLI , LI PENGCHENG , LUO WEIHUA , GONG BIYING , LUO QINGMING
Published: May 2010

Cortical spreading depression (CSD) is a wave of neuronal and glial depolarization that propagates across the cortex at a rate of 2–5 mm/min accompanied by reversible electroencephalogram (EEG) suppression, a negative shift of direct current (DC) potential, and change of optical intrinsic signals (OIS). Propagation velocity of CSD is an important parameter used to study this phenomenon. It is commonly determined in an electrophysiological way that measures the time required for a CSD wave to pass along two electrodes. Since the electrophysiology technique fails to reveal the spreading pattern of CSD, velocity calculated in this manner might be inaccurate. In this study, we combined the electrophysiological recording and OIS imaging (OISI) for detecting changes in DC potential and OIS during CSD simultaneously. An optical method based on OISI to determine the CSD velocity, which is measured by generating a series of regions of interest (ROI) perpendicular to the advancing wavefront along propagation direction of CSD at different time points and then dividing by the distance between ROIs over time, is presented. Comparison of the accuracy of the two approaches in determining the CSD velocity is made as well. The average rate of 33 CSDs is 3.52 ± 0.87 mm/min by use of the optical method and 4.36 ± 1.65 mm/min by use of the electrophysiological method. Because of the information about spreading pattern of CSD provided optically, the velocity determined by OISI is of smaller deviation and higher accuracy.
WAVELET-BASED PALM VEIN RECOGNITION SYSTEM
Authors: LI QIANG , ZENG YAN'AN , YANG KUNTAO
Published: May 2010

A new personal recognition system using the palm vein pattern is presented in this article. It is the first time that the palm vein pattern is used for personal recognition. The texture feature of palm vein is extracted by wavelet decomposition. With our palm vein image database, we employed the nearest neighbor (NN) classifier to test the performance of the system. Experimental results show that the algorithm based on wavelet transform can reach a correct recognition rate (CRR) of 98.8%.
COMPARISON OF OPTICAL POLARIMETRY AND DIFFUSION TENSOR MR IMAGING FOR ASSESSING MYOCARDIAL ANISOTROPY
Authors: WALLENBURG MARIKA A. , POP MIHAELA , WOOD MICHAEL F. G. , GHOSH NIRMALYA , WRIGHT GRAHAM A. , VITKIN I. ALEX
Published: May 2010

We have recently proposed an optical method for assessing heart structure that uses polarized light measurement of birefringence as an indicator of tissue anisotropy. The highly aligned nature of healthy cardiac muscle tissue has a detectable effect on the polarization of light, resulting in a measurable phase shift ("retardance"). When this organized tissue structure is perturbed, for example after cardiac infarction (heart attack), scar tissue containing disorganized collagen is formed, causing a decrease in the measured retardance values. However, these are dependent not only on tissue anisotropy, but also on the angle between the tissue's optical anisotropy direction and the beam interrogating the sample. To remove this experimental ambiguity, we present a method that interrogates the sample at two different incident beam angles, thus yielding enough information to uniquely determine the true magnitude and orientation of the tissue optical anisotropy. We use an infarcted porcine heart model to compare these polarimetry-derived anisotropy metrics with those obtained with diffusion tensor magnetic resonance imaging (DT-MRI). The latter yields the anisotropy and the direction of tissue water diffusivity, providing an independent measure of tissue anisotropy. The optical and MR results are thus directly compared in a common ex vivo biological model of interest, yielding reasonable agreement but also highlighting some technique-specific differences.
Image Sticking Resistant Liquid Crystal Display Driven by Fringe Electric Field for Mobile Applicaitions
Authors: Seen Seung Min , Kim Mi Sook , Lee Seung Hee
Published: May 2010

We propose image sticking resistant liquid crystal display (LCD) driven by fringe electric field for mobile application. For use of an alignment layer with polyamic acid (PA) type without cross link agent, impurity ions absorbed on the alignment layer easily discharge irrespective of liquid crystal (LC) because there is not any cross link agent which prevents discharging the ions, resulting in that image sticking easily disappears. For a panel with use of an alignment layer with polyimide (PI) type, time dependant flicker value is less than 2 dB and very steady while it is more than 10 dB and dramatically changes for a panel with the PA coated. From the result, we can know the PA coated panel without cross link agent has advantage in fast discharge of impurity ions when voltage is off, which is very favorable to an approach to image sticking free LCD driven by fringe electric field for mobile devices.
DOLFIN
Authors: Logg Anders , Wells Garth N.
Published: May 2010

We describe here a library aimed at automating the solution of partial differential equations using the finite element method. By employing novel techniques for automated code generation, the library combines a high level of expressiveness with efficient computation. Finite element variational forms may be expressed in near mathematical notation, from which low-level code is automatically generated, compiled, and seamlessly integrated with efficient implementations of computational meshes and high-performance linear algebra. Easy-to-use object-oriented interfaces to the library are provided in the form of a C++ library and a Python module. This article discusses the mathematical abstractions and methods used in the design of the library and its implementation. A number of examples are presented to demonstrate the use of the library in application code.
PRIMME
Authors: Stathopoulos Andreas , McCombs James R.
Published: May 2010

This article describes the PRIMME software package for solving large, sparse Hermitian standard eigenvalue problems. The difficulty and importance of these problems have increased over the years, necessitating the use of preconditioning and near optimally converging iterative methods. However, the complexity of tuning or even using such methods has kept them outside the reach of many users. Responding to this problem, we have developed PRIMME, a comprehensive package that brings state-of-the-art methods from “bleeding edge” to production, with the best possible robustness, efficiency, and a flexible, yet highly usable interface that requires minimal or no tuning. We describe (1) the PRIMME multimethod framework that implements a variety of algorithms, including the near optimal methods GD+kand JDQMR; (2) a host of algorithmic innovations and implementation techniques that endow the software with its robustness and efficiency; (3) a multilayer interface that captures our experience and addresses the needs of both expert and end users.
Feature-preserving triangular geometry images for level-of-detail representation of static and skinned meshes
Authors: Feng Wei-Wen , Kim Byung-Uck , Yu Yizhou , Peng Liang , Hart John
Published: May 2010

Geometry images resample meshes to represent them as texture for efficient GPU processing by forcing a regular parameterization that often incurs a large amount of distortion. Previous approaches broke the geometry image into multiple rectangular or irregular charts to reduce distortion, but complicated the automatic level of detail one gets from MIP-maps of the geometry image.

We introduce triangular-chart geometry images and show this new approach better supports the GPU-side representation and display of skinned dynamic meshes, with support for feature preservation, bounding volumes, and view-dependent level of detail. Triangular charts pack efficiently, simplify the elimination of T-junctions, arise naturally from an edge-collapse simplification base mesh, and layout more flexibly to allow their edges to follow curvilinear mesh features. To support the construction and application of triangular-chart geometry images, this article introduces a new spectral clustering method for feature detection, and new methods for incorporating skinning weights and skinned bounding boxes into the representation. This results in a tenfold improvement in fidelity when compared to quad-chart geometry images.
Temporal upsampling of performance geometry using photometric alignment
Authors: Wilson Cyrus A. , Ghosh Abhijeet , Peers Pieter , Chiang Jen-Yuan , Busch Jay , Debevec Paul
Published: May 2010

We present a novel technique for acquiring detailed facial geometry of a dynamic performance using extended spherical gradient illumination. Key to our method is a new algorithm for
jointly
aligning two photographs, under a gradient illumination condition and its complement, to a full-on tracking frame, providing dense temporal correspondences under changing lighting conditions. We employ a two-step algorithm to reconstruct detailed geometry for
every
captured frame. In the first step, we coalesce information from the gradient illumination frames to the full-on tracking frame, and form a temporally aligned photometric normal map, which is subsequently combined with dense stereo correspondences yielding a detailed geometry. In a second step, we propagate the detailed geometry back to every captured instance guided by the previously computed dense correspondences. We demonstrate reconstructed dynamic facial geometry, captured using moderate to video rates of acquisition, for every captured frame.
Programmable rendering of line drawing from 3D scenes
Authors: Grabli Stéphane , Turquin Emmanuel , Durand Frédo , Sillion François X.
Published: May 2010

This article introduces a programmable approach to nonphotorealistic line drawings from 3D models, inspired by programmable shaders in traditional rendering. This approach relies on the assumption generally made in NPR that style attributes (color, thickness, etc.) are chosen depending on generic properties of the scene such as line characteristics or depth discontinuities, etc. We propose a new image creation model where all operations are controlled through user-defined procedures in which the relations between style attributes and scene properties are specified. Aview mapdescribing all relevant support lines in the drawing and their topological arrangement is first created from the 3D model so as to ensure the continuity of all scene properties along its edges; a number of style modules operate on this map, by procedurally selecting, chaining, or splitting lines, before creating strokes and assigning drawing attributes. Consistent access to properties of the scene is provided from the different elements of the map that are manipulated throughout the whole process. The resulting drawing system permits flexible control of all elements of drawing style: First, different style modules can be applied to different types of lines in a view; second, the topology and geometry of strokes are entirely controlled from the programmable modules; and third, stroke attributes are assigned procedurally and can be correlated at will with various scene or view properties. We illustrate the components of our system and show how style modules successfully encode stylized visual characteristics that can be applied across a wide range of models.
Semantic self-assessment of query results in dynamic environments
Authors: Payton Jamie , Julien Christine , Roman Gruia-Catalin , Rajamani Vasanth
Published: May 2010

Queries are convenient abstractions for the discovery of information and services, as they offer content-based information access. In distributed settings, query semantics are well-defined, for example, queries are often designed to satisfy ACID transactional properties. When query processing is introduced in a dynamic network setting, achieving transactional semantics becomes complex due to the open and unpredictable environment. In this article, we propose a query processing model for mobile ad hoc and sensor networks that is suitable for expressing a wide range of query semantics; the semantics differ in the degree of consistency with which query results reflect the state of the environment during query execution. We introduce several distinct notions of consistency and formally express them in our model. A practical and significant contribution of this article is a protocol for query processing that automatically assesses and adaptively provides an achievable degree of consistency given the operational environment throughout its execution. The protocol attaches an assessment of the achieved guarantee to returned query results, allowing precise reasoning about a query with a range of possible semantics. We evaluate the performance of this protocol and demonstrate the benefits accrued to applications through examples drawn from an industrial application.
PIRATE
Authors: Illikkal Ramesh , Chadha Vineet , Herdrich Andrew , Iyer Ravi , Newell Donald
Published: May 2010

As new multi-threaded usage models such as virtualization and consolidation take advantage of multiple cores in CMP architectures, the impact of shared resource contention between VMs and user-level applications introduces Quality of Service(QoS) concerns and challenges. QoS-aware management of these shared platform resources is therefore becoming increasingly important. Various QoS schemes for resource management have been recently proposed, but most of these prior efforts have been focused on controlling individual resource allocation based on priority information passed down from the OS or Hypervisor to system resources. The complexity of this approach increases when multiple levels of resources are associated with an application's performance and power consumption. In this paper we employ simpler rate-based QoS mechanisms which control the execution rate of competing applications. To enable differentiation between simultaneously running applications' performance and power consumption, these rate mechanisms need to dynamically adjust the execution of application. Our proposed PI-RATE architecture introduces a control-theoretic approach to dynamically adjust the execution rate of each application based on the QoS target and monitored resource utilization. We evaluate three modes of PI-RATE architecture - cache QoS targets, performance QoS targets and power QoS targets - to show that the PI-RATE architecture is flexible and effective at enabling QoS in a CMP platform.
Towards characterizing cloud backend workloads
Authors: Mishra Asit K. , Hellerstein Joseph L. , Cirne Walfredo , Das Chita R.
Published: May 2010

The advent of cloud computing promises highly available, efficient, and flexible computing services for applications such as web search, email, voice over IP, and web search alerts. Our experience at Google is that realizing the promises of cloud computing requires an extremely scalable backend consisting of many large compute clusters that are shared by application tasks with diverse service level requirements for throughput, latency, and jitter. These considerations impact (a) capacity planning to determine which machine resources must grow and by how much and (b) task scheduling to achieve high machine utilization and to meet service level objectives.

Both capacity planning and task scheduling require a good understanding of task resource consumption (e.g., CPU and memory usage). This in turn demands simple and accurate approaches to workload classification-determining how to form groups of tasks (workloads) with similar resource demands. One approach to workload classification is to make each task its own workload. However, this approach scales poorly since tens of thousands of tasks execute daily on Google compute clusters. Another approach to workload classification is to view all tasks as belonging to a single workload. Unfortunately, applying such a coarse-grain workload classification to the diversity of tasks running on Google compute clusters results in large variances in predicted resource consumptions.

This paper describes an approach to workload classification and its application to the Google Cloud Backend, arguably the largest cloud backend on the planet. Our methodology for workload classification consists of: (1) identifying the workload dimensions; (2) constructing task classes using an off-the-shelf algorithm such as k-means; (3) determining the break points for qualitative coordinates within the workload dimensions; and (4) merging adjacent task classes to reduce the number of workloads. We use the foregoing, especially the notion of qualitative coordinates, to glean several insights about the Google Cloud Backend: (a) the duration of task executions is bimodal in that tasks either have a short duration or a long duration; (b) most tasks have short durations; and (c) most resources are consumed by a few tasks with long duration that have large demands for CPU and memory.
Systematically improving the quality of IT utilization data
Authors: Arlitt Martin , Farkas Keith , Iyer Subu , Kumaresan Preethi , Rafaeli Sandro
Published: May 2010

Efforts to reduce the cost of ownership for enterprise IT environments are spurring the development and deployment of data-driven management tools. Yet, IT data is imperfect and these imperfections can lead to inappropriate decisions that have significant technical and business consequences. In this paper, we begin by raising awareness of this problem through examples of the imperfections that occur, and a discussion of their causes and implications on IT management tasks. We then introduce a systematic approach for addressing such imperfections. Our approach allows best practices to be readily shared, simplifies the construction of IT data assurance solutions, and allows context-specific corrections to be applied until the root cause(s) of the imperfections can be fixed. To demonstrate the value of our solution, we describe a capacity planning use case. Application of our solution to an ongoing capacity planning effort reduced the (human) planner's time requirements by ≈3x to ≈6 hours, while enabling him to evaluate the data quality of ≈5x more applications and for 9 imperfection types rather than 1.
Blackbox prediction of the impact of DVFS on end-to-end performance of multitier systems
Authors: Chen Shuyi , Joshi Kaustubh R. , Hiltunen Matti A. , Schlichting Richard D. , Sanders William H.
Published: May 2010

Dynamic voltage and frequency scaling (DVFS) is a well-known technique for gaining energy savings on desktop and laptop computers. However, its use in server settings requires careful consideration of any potential impacts on end-to-end service performance of hosted applications. In this paper, we develop a simple metric called the \frequency gradient" that allows prediction of the impact of changes in processor frequency on the end-to-end transaction response times of multitier applications. We show how frequency gradients can be measured on a running system in a push-button manner without any prior knowledge of application semantics, structure, or configuration settings. Using experimental results, we demonstrate that the frequency gradients provide accurate predictions, and enable end-to-end performance-aware DVFS for mulitier applications.
Quantifying the sustainability impact of data center availability
Authors: Marwah Manish , Maciel Paulo , Shah Amip , Sharma Ratnesh , Christian Tom , Almeida Virgilio , Araújo Carlos , Souza Erica , Callou Gustavo , Silva Bruno , Galdino Sérgio , Pires Jose
Published: May 2010

Data center availability is critical considering the explosive growth in Internet services and people's dependence on them. Furthermore, in recent years, sustainability has become important. However, data center designers have little information on the sustainability impact of data center availability architectures. In this paper, we present an approach to estimate the sustainability impact of such architectures. Availability is computed using Stochastic Petri Net (SPN) models while an exergy-based lifecycle assessment (LCA) approach is used for quantifying sustainability impact. The approach is demonstrated on real life data center power infrastructure architectures. Five different architectures are considered and initial results show that quantification of sustainability impact provides important information to a data center designer in evaluating availability architecture choices.
Fair greening for DSL broadband access
Authors: Tsiaflakis Paschalis , Yi Yung , Chiang Mung , Moonen Marc
Published: May 2010

Given that broadband access networks are an integral part of the ICT infrastructure and that DSL is the most widely deployed broadband access technology, greening DSL has become important. Our recent work demonstrated a promising tradeoff between data rate performance and energy conservation. However, more greening still implies possibly lower data rate, and allocating this "price of greening" across interfering users needs to be fair. This paper proposes four for- mulations of fair greening in interference-limited networks, unifies them into one general representation, and develops a unified algorithm to solve them effectively. Simulations quantify the intuitions on fairness in greening DSL, as these four alternative approaches offer a range of choices between maintaining a high sum data rate and enforcing various definitions of fairness. Fairness of allocating the price of greening is also interesting in its own right.
The effects of the small GTPase RhoA on the muscarinic contraction of airway smooth muscle result from its role in regulating actin polymerization
Authors: Zhang Wenwu , Du Liping , Gunst Susan J.
Published: May 2010

The small GTPase RhoA increases the Ca2+ sensitivity of smooth muscle contraction and myosin light chain (MLC) phosphorylation by inhibiting the activity of MLC phosphatase. RhoA is also a known regulator of cytoskeletal dynamics and actin polymerization in many cell types. In airway smooth muscle (ASM), contractile stimulation induces MLC phosphorylation and actin polymerization, which are both required for active tension generation. The objective of this study was to evaluate the primary mechanism by which RhoA regulates active tension generation in intact ASM during stimulation with acetylcholine (ACh). RhoA activity was inhibited in canine tracheal smooth muscle tissues by expressing the inactive RhoA mutant, RhoA T19N, in the intact tissues or by treating them with the cell-permeant RhoA inhibitor, exoenzyme C3 transferase. RhoA inactivation reduced ACh-induced contractile force by ∼60% and completely inhibited ACh-induced actin polymerization but inhibited ACh-induced MLC phosphorylation by only ∼20%. Inactivation of MLC phosphatase with calyculin A reversed the reduction in MLC phosphorylation caused by RhoA inactivation, but calyculin A did not reverse the depression of active tension and actin polymerization caused by RhoA inactivation. The MLC kinase inhibitor, ML-7, inhibited ACh-induced MLC phosphorylation by ∼80% and depressed active force by ∼70% but did not affect ACh-induced actin polymerization, demonstrating that ACh-stimulated actin polymerization occurs independently of MLC phosphorylation. We conclude that the RhoA-mediated regulation of ACh-induced contractile tension in ASM results from its role in mediating actin polymerization rather than from effects on MLC phosphatase or MLC phosphorylation.
Subtype identification and functional characterization of ryanodine receptors in rat cerebral artery myocytes
Authors: Vaithianathan Thirumalini , Narayanan Damodaran , Asuncion-Chin Maria T. , Jeyakumar Loice H. , Liu Jianxi , Fleischer Sidney , Jaggar Jonathan H. , Dopico Alejandro M.
Published: May 2010

Ryanodine receptors (RyRs) regulate contractility in resistance-size cerebral artery smooth muscle, yet their molecular identity, subcellular location, and phenotype in this tissue remain unknown. Following rat resistance-size cerebral artery myocyte sarcoplasmic reticulum (SR) purification and incorporation into POPE-POPS-POPC (5:3:2; wt/wt) bilayers, unitary conductances of 110 ± 8, 334 ± 15, and 441 ± 27 pS in symmetric 300 mM Cs+were usually detected. The most frequent (34/40 bilayers) conductance (334 pS) decreased to ≤100 pS when Cs+was replaced with Ca2+. The predominant conductance displayed 66 bursts/min with at least three open and three closed states. The steady-state activity (NPo)-voltage curve was bell shaped, with NPodrastically decreasing when voltage was switched from −30 to −40 mV. NPoincreased when intracellular calcium (Ca2+i) was raised within 0.1–100 μM to abruptly diminish with higher Ca2+i. Thus maximal activity occurred within the Ca2+irange found in rat cerebral artery myocytes under physiological conditions. NPowas reduced by ruthenium red (80 μM), increased monotonically by caffeine (0.1–5 mM) or ryanodine (0.05–5 μM), and unaffected by heparin (2 mg/ml). This phenotype resembles that of cardiac RyR and recombinant RyR2. RT-PCR detected RyR1, RyR2, and RyR3 transcripts in cerebral artery myocytes. However, real-time PCR indicated that RyR2 was 4 and 1.5 times more abundant than RyR1 and RyR3, respectively. Consistently, Western blotting showed that the RyR2 product was very abundant. Immunofluorescence showed that each RyR isoform distributed differentially among subcellular compartments. In particular, RyR2 was drastically stronger in the subplasmalemma than in other compartments, underscoring the predominance of RyR2 in a compartment where SR is abundant. Consistently, RyR from SR-enriched membranes displayed pharmacological specificity typical of RyR2, being activated by digoxin (1 μM), resistant to dantrolene (100 μM), and shifted to a subconductance by neomycin (100 nM). Therefore, RyR2 is the predominant molecular and functional RyR that is expressed in the SR membrane of rat resistance-size cerebral artery myocytes.
Effects of negative pressures on epithelial tight junctions and migration in wound healing
Authors: Hsu Chih-Chin , Tsai Wen-Chung , Chen Carl Pai-Chu , Lu Yun-Mei , Wang Jong-Shyan
Published: May 2010

Negative-pressure wound therapy has recently gained popularity in chronic wound care. This study attempted to explore effects of different negative pressures on epithelial migration in the wound-healing process. The electric cell-substrate impedance sensing (ECIS) technique was used to create a 5 × 10−4 cm2 wound in the Madin-Darby canine kidney (MDCK) and human keratinocyte (HaCaT) cells. The wounded cells were cultured in a negative pressure incubator at ambient pressure (AP) and negative pressures of 75 mmHg (NP75), 125 mmHg (NP125), and 175 mmHg (NP175). The effective time (ET), complete wound healing time ( Tmax), healing rate ( Rheal), cell diameter, and wound area over time at different pressures were evaluated. Traditional wound-healing assays were prepared for fluorescent staining of cells viability, cell junction proteins, including ZO-1 and E-cadherin, and actins. Amount of cell junction proteins at AP and NP125 was also quantified. In MDCK cells, the ET (1.25 ± 0.27 h), Tmax (1.76 ± 0.32 h), and Rheal (2.94 ± 0.62 × 10−4 cm2/h) at NP125 were significantly ( P < 0.01) different from those at three other pressure conditions. In HaCaT cells, the Tmax (7.34 ± 0.29 h) and Rheal (6.82 ± 0.26 × 10−5 cm2/h) at NP125 were significantly ( P < 0.01) different from those at NP75. Prominent cell migration features were identified in cells at the specific negative pressure. Cell migration activities at different pressures can be documented with the real-time wound-healing measurement system. Negative pressure of 125 mmHg can help disassemble the cell junction to enhance epithelial migration and subsequently result in quick wound closure.
Reactive oxygen species alters the electrophysiological properties and raises [Ca2+]iin intracardiac ganglion neurons
Authors: Dyavanapalli Jhansi , Rimmer Katrina , Harper Alexander A.
Published: May 2010

We have investigated the effects of the reactive oxygen species (ROS) donors hydrogen peroxide (H2O2) and tert-butyl hydroperoxide ( t-BHP) on the intrinsic electrophysiological characteristics: ganglionic transmission and resting [Ca2+]iin neonate and adult rat intracardiac ganglion (ICG) neurons. Intracellular recordings were made using sharp microelectrodes filled with either 0.5 M KCl or Oregon Green 488 BAPTA-1, allowing recording of electrical properties and measurement of [Ca2+]i. H2O2and t-BHP both hyperpolarized the resting membrane potential and reduced membrane resistance. In adult ICG neurons, the hyperpolarizing action of H2O2was reversed fully by Ba2+and partially by tetraethylammonium, muscarine, and linopirdine. H2O2and t-BHP reduced the action potential afterhyperpolarization (AHP) amplitude but had no impact on either overshoot or AHP duration. ROS donors evoked an increase in discharge adaptation to long depolarizing current pulses. H2O2blocked ganglionic transmission in most ICG neurons but did not alter nicotine-evoked depolarizations. By contrast, t-BHP had no significant action on ganglionic transmission. H2O2and t-BHP increased resting intracellular Ca2+levels to 1.6 ( ± 0.6, n = 11, P < 0.01) and 1.6 ( ± 0.3, n = 8, P < 0.001), respectively, of control value (1.0, ∼60 nM). The ROS scavenger catalase prevented the actions of H2O2, and this protection extended beyond the period of application. Superoxide dismutase partially shielded against the action of H2O2, but this was limited to the period of application. These data demonstrate that ROS decreases the excitability and ganglionic transmission of ICG neurons, attenuating parasympathetic control of the heart.