bluuebunny/crossref_metadata_2025 huggingface dataset:
TLR4 Ligands Augment Antigen-Specific CD8
+
T Lymphocyte Responses Elicited by a Viral Vaccine Vector
Authors: Rhee Elizabeth G. , Kelley R. Phelps , Agarwal Isha , Lynch Diana M. , La Porte Annalena , Simmons Nathaniel L. , Clark Sarah L. , Barouch Dan H.
Published: July 2010

Toll-like receptor (TLR) ligands are critical activators of innate immunity and are being developed as vaccine adjuvants. However, their utility in conjunction with viral vector-based vaccines remains unclear. In this study, we evaluated the impact of a variety of TLR ligands on antigen-specific CD8
+
T lymphocyte responses elicited by a recombinant adenovirus serotype 26 (rAd26) vector expressing simian immunodeficiency virus Gag in mice. The TLR3 ligand poly(I:C) suppressed Gag-specific cellular immune responses, whereas the TLR4 ligands lipopolysaccharide and monophosphoryl lipid A substantially augmented the magnitude and functionality of these responses by a MyD88- and TRIF-dependent mechanism. These data demonstrate that TLR ligands can modulate the immunogenicity of viral vaccine vectors both positively and negatively. Moreover, these findings suggest the potential utility of TLR4 ligands as adjuvants for rAd vector-based vaccines.
Leukocyte Immunoglobulin-Like Receptors Maintain Unique Antigen-Presenting Properties of Circulating Myeloid Dendritic Cells in HIV-1-Infected Elite Controllers
Authors: Huang Jinghe , Burke Patrick S. , Cung Thai Duong Hong , Pereyra Florencia , Toth Ildiko , Walker Bruce D. , Borges Luis , Lichterfeld Mathias , Yu Xu G.
Published: July 2010

Elite controllers maintain undetectable levels of HIV-1 replication in the absence of antiretroviral therapy, but the correlates of immune protection in this patient population are ill defined. Here, we demonstrate that in comparison to patients with progressive HIV-1 infection or healthy persons not infected with HIV-1, elite controllers have circulating myeloid dendritic cells with significantly increased antigen-presenting properties, while their ability to secrete proinflammatory cytokines is substantially diminished. This unique functional profile is associated with a distinct surface expression pattern of immunomodulatoryleukocyte-immunoglobulin-likereceptors (LILR) and a strong and selective upregulation of LILRB1 and LILRB3. Blockade of these two receptors by monoclonal antibodies or short interfering RNA (siRNA) abrogated the specific antigen-presenting properties of dendritic cells, implying an important regulatory role of these molecules. These data reveal previously unrecognized innate components of immune protection against HIV-1 in elite controllers and offer novel perspectives for the manipulation of host immunity for the prevention and treatment of HIV-1 infection.
Evidence for Avian and Human Host Cell Factors That Affect the Activity of Influenza Virus Polymerase
Authors: Moncorgé Olivier , Mura Manuela , Barclay Wendy S.
Published: July 2010

Typical avian influenza A viruses do not replicate efficiently in humans. The molecular basis of host range restriction and adaptation of avian influenza A viruses to a new host species is still not completely understood. Genetic determinants of host range adaptation have been found on the polymerase complex (PB1, PB2, and PA) as well as on the nucleoprotein (NP). These four viral proteins constitute the minimal set for transcription and replication of influenza viral RNA. It is widely documented that in human cells, avian-derived influenza A viral polymerase is poorly active, but despite extensive study, the reason for this blockade is not known. We monitored the activity of influenza A viral polymerases in heterokaryons formed between avian (DF1) and human (293T) cells. We have discovered that a positive factor present in avian cells enhances the activity of the avian influenza virus polymerase. We found no evidence for the existence of an inhibitory factor for avian virus polymerase in human cells, and we suggest, instead, that the restriction of avian influenza virus polymerases in human cells is the consequence of the absence or the low expression of a compatible positive cofactor. Finally, our results strongly suggest that the well-known adaptative mutation E627K on viral protein PB2 facilitates the ability of a human positive factor to enhance replication of influenza virus in human cells.
Varicella-Zoster Virus Immediate-Early Protein 62 Blocks Interferon Regulatory Factor 3 (IRF3) Phosphorylation at Key Serine Residues: a Novel Mechanism of IRF3 Inhibition among Herpesviruses
Authors: Sen Nandini , Sommer Marvin , Che Xibing , White Kris , Ruyechan William T. , Arvin Ann M.
Published: July 2010

Varicella-zoster virus (VZV) is an alphaherpesvirus that is restricted to humans. VZV infection of differentiated cells within the host and establishment of latency likely require evasion of innate immunity and limited secretion of antiviral cytokines. Since interferons (IFNs) severely limit VZV replication, we examined the ability of VZV to modulate the induction of the type I IFN response in primary human embryonic lung fibroblasts (HELF). IFN-β production was not detected, and transcription of two interferon response factor 3 (IRF3)-dependent interferon-stimulated genes (ISGs), ISG54 and ISG56, in response to poly(I:C) stimulation was downregulated in VZV-infected HELF. Inhibition of IRF3 function did not require VZV replication; the viral immediate-early protein 62 (IE62) alone was sufficient to produce this effect. IE62 blocked TBK1-mediated IFN-β secretion and IRF3 function, as shown in an IFN-stimulated response element (ISRE)-luciferase reporter assay. However, IRF3 function was preserved if constitutively active IRF3 (IRF3-5D) was expressed in VZV-infected or IE62-transfected cells, indicating that VZV interferes with IRF3 phosphorylation. IE62-mediated inhibition was mapped to blocking phosphorylation of at least three serine residues on IRF3. However, IE62 binding to TBK1 or IRF3 was not detected and IE62 did not perturb TBK1-IRF3 complex formation. IE62-mediated inhibition of IRF3 function was maintained even if IE62 transactivator activity was disrupted. Thus, IE62 has two critical but discrete roles following VZV entry: to induce expression of VZV genes and to disarm the IFN-dependent antiviral defense through a novel mechanism that prevents IRF3 phosphorylation.
Annexin 2 Is Not Required for Human Immunodeficiency Virus Type 1 Particle Production but Plays a Cell Type-Dependent Role in Regulating Infectivity
Authors: Rai Tia , Mosoian Arevik , Resh Marilyn D.
Published: July 2010

During assembly and budding of retroviruses, host cell proteins are incorporated into viral particles. Identification of virion-associated proteins may help pinpoint key cellular components required for virus production and function. The cellular protein annexin 2 (Anx2) is incorporated into HIV-1 particles, and knockdown of Anx2 has been reported to cause defects in Gag processing and infectivity of HIV-1 particles in macrophages. Here, we tested whether Anx2 was required for HIV-1 production in other cell types capable of producing HIV-1 virions. Endogenous Anx2 levels were knocked down by ∼98% using lentivirus encoding short hairpin RNAs (shRNAs) or small interfering RNAs (siRNAs) targeting Anx2. Under these conditions, there was no reduction in HIV-1 virus-like particle (VLP) production in either COS-1, 293T, or Jurkat T cells or primary human monocyte-derived macrophages (MDMs). Murine embryonic fibroblasts derived from Anx2
−/−
mice produced the same levels of VLPs as matched cells from wild-type mice. The calcium-mediated spike in VLP production still occurred in Anx2-depleted COS-1 cells, and there was no apparent alteration in the intracellular Gag localization. Overexpression of Anx2 in
trans
had no effect on Gag processing or VLP production. Neither Anx2 depletion nor Anx2 overexpression altered the infectivity of HIV-1 particles produced by COS-1 or 293T cells. However, supernatants containing virus from Anx2 siRNA-treated primary human MDMs exhibited decreased infectivity. These data indicate that Anx2 is not required for HIV-1 assembly or Gag processing but rather plays a cell type-dependent role in regulating production of infectious HIV-1 by macrophages.
Late-night salivary cortisol in normal subjects and in patients with Cushing’s syndrome
Authors: Jeyaraman K , Ammini A C , Nandita G , Dwivedi S N
Published: July 2010

Background

Late-night salivary cortisol is used as a screening test for Cushing’s syndrome (CS) in many European and American countries. However, its utility has not been studied in an Asian-Indian population.

Objective

To establish the reference range in Asian-Indians and to evaluate its usefulness in the diagnosis of CS.

Methods

Three groups of subjects were studied: normal subjects, patients with suspected CS, and patients with proven CS. All participants collected saliva at 23:00 h using a Salivette. Salivary cortisol was measured using an automated electrochemiluminescence assay.

Results

There were 56 normal subjects, 40 patients with suspected CS, and 30 with proven CS. Of the 40 with suspected CS, three were confirmed to have CS. The remaining 37 served as control patients. The 97.5th centile of the late-night salivary cortisol concentrations in normal subjects was 10.87 nmol/l. The mean±SD 23:00 h salivary cortisol concentration in control patients and those with confirmed CS was 3.21±2.36 nmol/l and 32.33±44.14 nmol/l, respectively. All the control patients and 30.3% (10/33) of patients with CS had a salivary cortisol concentration of <10.87 nmol/l. With the use of a receiver operating characteristic curve, a cut-off of 4.55 nmol/l gave a sensitivity of 93.9% and specificity of 81.1%. However, as this cut-off is less than the functional sensitivity of the assay, it may not be clinically applicable.

Conclusions

The reference range for late-night salivary cortisol in our population was <10.87 nmol/l. With this cut-off, the sensitivity was 69.2% and specificity 100%. Even though this automated electrochemiluminescence assay is easy and quick to use, its clinical utility in measuring the low salivary cortisol concentrations needs further investigation.
Feasibility and safety of outpatient radiofrequency catheter ablation procedures for atrial fibrillation
Authors: Haegeli Laurent M , Duru Firat , Lockwood Evan E , Lüscher Thomas F , Sterns Laurence D , Novak Paul G , Leather Richard A
Published: July 2010

Introduction

Percutaneous catheter ablation for atrial fibrillation (AF) is a procedure performed typically in an inpatient setting. The feasibility and safety of catheter ablation in patients with paroxysmal and persistent AF were evaluated on an outpatient basis.

Methods

230 AF ablation procedures were performed in 206 patients (74% male; mean age 56±9 years). Patients were admitted to the hospital outpatient facility in the morning for the AF ablation procedure on the same day. The ablation strategy consisted of wide area circumferential lines around both ipsilateral pulmonary veins. After monitoring in the outpatient service, patients were discharged on the same day, if they were clinically stable.

Results

Mean procedure time was 201±31 min. Major complications occurred in seven patients (3%). One patient (0.4%) suffered a minor stroke and six patients had pericardial tamponade requiring percutaneous drainage. Patients could be discharged on the same day following 205 (89%) procedures. Among the 148 patients whose clinical outcome was assessed at 6 months, 127 (86%) had a reduction of the total symptomatic AF episodes, compared to pre-ablation, with a complete lack of symptoms in 101 patients (68%).

Conclusion

Catheter ablation of AF on the day of admission is feasible and safe with a low risk of complications. The vast majority of the patients can be discharged on the same day.
Sedimentological and Biological Changes in the Windsor Mudflat, an Area of Induced Siltation
Authors: Turk Ted R. , Risk Michael J. , Hirtle Roy W. M. , Yeo Ross K.
Published: July 2010

The causeway-induced mudflat at Windsor, Nova Scotia, was studied to determine the effect of rapid sedimentation on the sedimentological and biological characteristics of an intertidal mudflat. Compared to typical Minas Basin mudflats, the Windsor flat has high water content, (50% vs. 30% wet wt, approximately) small grain sizes, and elevated organic carbon content (0.82% vs. 0.24% dry wt). The two principal infaunal species of the Windsor flat, the amphipod Corophium volutator and the clam Macoma balthica, are less abundant than in nearby typical flats (~840 vs. ~13 000/m2 and ~640 vs. ~1500/m2, respectively), while the polychaete Heteromastus filiformis is particularly abundant at Windsor. Macoma balthica at Windsor grow faster and have a shorter lifespan (~6 yr vs. ~13 yr) than at other Minas Basin flats. Compared to other Minas Basin Macoma, the weight of Windsor Macoma increases more slowly with increasing shell size, possibly an adaptation to the more fluid Windsor sediments.These sedimentological and biological characteristics exist at Windsor nearly 10 yr after the start of flat development and show little tendency to approach typical mudflat characteristics. Our results indicate, therefore, that secondary productivity of Macoma and Corophium could be reduced by about two-thirds for at least a decade in existing Minas Basin mudflats that are covered by Windsor-type sediments as a result of the construction of a tidal power dam.Key words: Bay of Fundy, tidal power, sedimentation, water content, organic carbon, infauna, Corophium volutator, Macoma balthica, growth, mortality
Models of Ammonia Excretion for Brook Trout (Salvelinus fontinalis) and Rainbow Trout (Salmo gairdneri)
Authors: Paulson Larry J.
Published: July 2010

Ammonia excretion by brook trout (Salvelinus fontinalis) and rainbow trout (Salmo gairdneri) was measured in relation to nitrogen consumption, body weight (15–154 g for rainbow trout and 50–360 g for brook trout), and temperature (11.2–21.0 °C) under laboratory conditions. Four natural diets, collected from Castle Lake, California, and a commercial pellet diet were fed to the trout in gelatin capsules at feeding rates from 2.5 to 5% body weight∙d−1. Nitrogen consumption was the most important factor influencing ammonia excretion, followed by body weight and temperature. Testing the models with an independent data set revealed good agreement between measured and predicted rates of excretion. The models seem to estimate adequately ammonia excretion by trout in both natural and artificial aquatic systems.Key words: models, ammonia excretion, nitrogen consumption, body weight, temperature, multiple regression, rainbow trout, brook trout
Some Sources of Variability in Determination of Digestive Enzyme Activity in Zooplankton
Authors: Mayzaud P.
Published: July 2010

Enzyme activity measurements, sometimes used to ascertain the distribution and quantification of physiological activity of marine zooplankton, are sensitive to a number of sources of variability of both methodological and environmental origins. To facilitate multiple enzyme determinations on a single sample, we have developed a method of acetone extraction from neritic zooplankton followed by 50% glycerol homogenization of the resulting powder. An increase in activity was found compared with that of glycerol homogenates of live zooplankton. Because saturation of 50% glycerol was found when extracting increasing amounts of acetone powder, care was taken to prepare homogenates with an identical amount of powder. The problem of protein solubility in the homogenization medium is discussed. The method is repeatable and yields results which are little influenced by short-term storage of animals before extraction but are strongly influenced by species composition of the plankton sample and to a lesser extent by spatial variability of the plankton populations.Key words: variability, determination, digestive enzyme activity, zooplankton
Relationship Between Thermal Stability and Summer Oxygen Depletion in a Prairie Pothole Lake
Authors: Papst M. H. , Mathias J. A. , Barica J.
Published: July 2010

Periods of summer oxygen depletion (summerkill), occurring in shallow prairie lakes, are dependent on the collapse of algae blooms but are not an obligatory result of the collapse. A period of thermal instability following this bloom collapse, or coincidental with it, is a necessary requirement. Wind stress and night-time air temperature are the principal factors determining the degree of thermal stability. These findings explain the speed with which oxygen depletion can occur, that the occurrence of algal biomass collapses without severe oxygen depletion (partial collapses), and the correlation between the occurrence of periods of lake oxygen depletion and changing weather conditions.Key words: lake, summerkill, anoxia, mixing, oxygen depletion, thermal stability, weather, Aphanizomenon
Brain Acetylcholinesterase Inhibition and Hepatic Activation of Acephate and Fenitrothion in Rainbow Trout (Salmo gairdneri)
Authors: Klaverkamp J. F. , Hobden B. R.
Published: July 2010

Two factors, potency of brain acetylcholinesterase (AChE) inhibition and biotransformation by liver homogenate, were investigated to understand the temperature-dependent toxicity of fenitrothion (FTN) in rainbow trout (Salmo gairdneri) and the 600- to 1000-fold differences in concentration between FTN and another organophosphate (OP) insecticide, acephate (ATE), required to produce death in these trout. Concentrations required to produce 50% inhibition of brain AChE were similar for ATE and FTN, ~125 mmol/L and 80 mmol/L, respectively, whereas fenitrooxon (FTO), the oxidative desulfuration metabolite of FTN, was approximately five orders of magnitude more potent. Incubation with liver homogenate, however, demonstrated that a more potent brain AChE inhibitor was produced from ATE, but not from FTN. It is concluded that hepatic biotransformation of FTN to FTO does not explain previous observations of FTN temperature dependency and differences in concentrations producing lethality.Key words: acephate, acetylcholinesterase, biotransformation, brain, fenitrothion, fenitrooxon, liver
Storage Characteristics of Small and Large Walleye Pollock (Theragra chalcogramma) Held in Ice
Authors: Kramer D. E. , Nordin D. M. A.
Published: July 2010

Organoleptic changes and trimethylamine (TMA) levels in the muscle of small and large walleye pollock were determined after 0, 5, and 10 d of iced storage. Small pollock (≤ 50 cm in length) spoiled appreciably faster than large pollock (≥ 60 cm) as measured by organoleptic assessment of flavor and odor. Mean TMA levels in small and large pollock were not significantly different at any of the three iced storage times; however, variation among fish was large for both sizes after 10 d of iced storage. Also, TMA level along the length of individual pollock varied greatly, indicating whole fillets should be used for TMA analysis in this species. The size and kind of homogenizer used did not affect the efficiency of TMA extraction from the flesh.Key words: walleye pollock, Theragra chalcogramma; iced storage, organoleptic assessment, trimethylamine
ON THE QUANTUM COMPLEXITY OF EVALUATING THE TUTTE POLYNOMIAL
Authors: AHMADI HAMED , WOCJAN PAWEL
Published: July 2010

We show that the problem of approximately evaluating the Tutte polynomial of triangular graphs at the points (q, 1/q) of the Tutte plane is BQP-complete for (most) roots of unity q. We also consider circular graphs and show that the problem of approximately evaluating the Tutte polynomial of these graphs at the point (e2πi/5, e-2πi/5) is DQC1-complete and at points [Formula: see text] for some integer k is in BQP.

To show that these problems can be solved by a quantum computer, we rely on the relation of the Tutte polynomial of a planar G graph with the Jones and HOMFLY polynomial of the alternating link D(G) given by the medial graph of G. In the case of our graphs the corresponding links are equal to the plat and trace closures of braids. It is known how to evaluate the Jones and HOMFLY polynomial for closures of braids.

To establish the hardness results, we use the property that the images of the generators of the braid group under the irreducible Jones–Wenzl representations of the Hecke algebra have finite order. We show that for each braid b we can efficiently construct a braid [Formula: see text] such that the evaluation of the Jones and HOMFLY polynomials of their closures at a fixed root of unity leads to the same value and that the closures of [Formula: see text] are alternating links.
POLYNOMIAL LOCAL SEARCH IN THE POLYNOMIAL HIERARCHY AND WITNESSING IN FRAGMENTS OF BOUNDED ARITHMETIC
Authors: BECKMANN ARNOLD , BUSS SAMUEL R.
Published: July 2010

The complexity class of [Formula: see text]-polynomial local search (PLS) problems is introduced and is used to give new witnessing theorems for fragments of bounded arithmetic. For 1 ≤ i ≤ k + 1, the [Formula: see text]-definable functions of [Formula: see text] are characterized in terms of [Formula: see text]-PLS problems. These [Formula: see text]-PLS problems can be defined in a weak base theory such as [Formula: see text], and proved to be total in [Formula: see text]. Furthermore, the [Formula: see text]-PLS definitions can be skolemized with simple polynomial time functions, and the witnessing theorem itself can be formalized, and skolemized, in a weak base theory. We introduce a new [Formula: see text]-principle that is conjectured to separate [Formula: see text] and [Formula: see text].
A RE-EVALUATION OF BIOMEDICAL NAMED ENTITY–TERM RELATIONS
Authors: OHTA TOMOKO , PYYSALO SAMPO , KIM JIN-DONG , TSUJII JUN'ICHI
Published: July 2010

Text mining can support the interpretation of the enormous quantity of textual data produced in biomedical field. Recent developments in biomedical text mining include advances in the reliability of the recognition of named entities (NEs) such as specific genes and proteins, as well as movement toward richer representations of the associations of NEs. We argue that this shift in representation should be accompanied by the adoption of a more detailed model of the relations holding between NEs and other relevant domain terms. As a step toward this goal, we study NE–term relations with the aim of defining a detailed, broadly applicable set of relation types based on accepted domain standard concepts for use in corpus annotation and domain information extraction approaches.
Image deblurring using inertial measurement sensors
Authors: Joshi Neel , Kang Sing Bing , Zitnick C. Lawrence , Szeliski Richard
Published: July 2010

We present a deblurring algorithm that uses a hardware attachment coupled with a natural image prior to deblur images from consumer cameras. Our approach uses a combination of inexpensive gyroscopes and accelerometers in an energy optimization framework to estimate a blur function from the camera's acceleration and angular velocity during an exposure. We solve for the camera motion at a high sampling rate
during
an exposure and infer the latent image using a joint optimization. Our method is completely automatic, handles per-pixel, spatially-varying blur, and out-performs the current leading image-based methods. Our experiments show that it handles large kernels -- up to at least 100 pixels, with a typical size of 30 pixels. We also present a method to perform "ground-truth" measurements of camera motion blur. We use this method to validate our hardware and deconvolution approach. To the best of our knowledge, this is the first work that uses 6 DOF inertial sensors for dense, per-pixel spatially-varying image deblurring and the first work to gather dense ground-truth measurements for camera-shake blur.
Spatial relationship preserving character motion adaptation
Authors: Ho Edmond S. L. , Komura Taku , Tai Chiew-Lan
Published: July 2010

This paper presents a new method for editing and retargeting motions that involve close interactions between body parts of single or multiple articulated characters, such as dancing, wrestling, and sword fighting, or between characters and a restricted environment, such as getting into a car. In such motions, the implicit spatial relationships between body parts/objects are important for capturing the scene semantics. We introduce a simple structure called an interaction mesh to represent such spatial relationships. By minimizing the local deformation of the interaction meshes of animation frames, such relationships are preserved during motion editing while reducing the number of inappropriate interpenetrations. The interaction mesh representation is general and applicable to various kinds of close interactions. It also works well for interactions involving contacts and tangles as well as those without any contacts. The method is computationally efficient, allowing real-time character control. We demonstrate its effectiveness and versatility in synthesizing a wide variety of motions with close interactions.
envyLight
Authors: Pellacini Fabio
Published: July 2010

Scenes lit with high dynamic range environment maps of real-world environments exhibit all the complex nuances of natural illumination. For applications that need lighting adjustments to the rendered images, editing environment maps directly is still cumbersome. First, designers have to determine which region in the environment map is responsible for the specific lighting feature (e.g. diffuse gradients, highlights and shadows) they desire to edit. Second, determining the parameters of image-editing operations needed to achieve specific changes to the selected lighting feature requires extensive trial-and-error.

This paper presents
envyLight
, an interactive interface for editing natural illumination that combines an algorithm to select environment map regions, by sketching strokes on lighting features in the rendered image, with a small set of editing operations to quickly adjust the selected feature. The
envyLight
selection algorithm works well for indoor and outdoor lighting corresponding to rendered images where lighting features vary widely in number, size, contrast and edge blur. Furthermore,
envyLight
selection is general with respect to material type, from matte to sharp glossy, and the complexity of scenes' shapes.
envyLight
editing operations allow designers to quickly alter the position, contrast and edge blur of the selected lighting feature and can be keyframed to support animation.
Toward evaluating material design interface paradigms for novice users
Authors: Kerr William B. , Pellacini Fabio
Published: July 2010

Material design is the process by which artists specify the reflectance properties of a surface, such as its diffuse color and specular roughness. We present a user study to evaluate the relative benefits of different material design interfaces, focusing on novice users since they stand to gain the most from intuitive interfaces. Specifically, we investigate the editing of the parameters of analytic bidirectional distribution functions (BRDFs) using three interface paradigms:
physical sliders
by which users set the parameters of analytic BRDF models, such as diffuse albedo and specular roughness;
perceptual sliders
by which users set perceptually-inspired parameters, such as diffuse luminance and gloss contrast; and
image navigation
by which material variations are displayed in arrays of image thumbnails and users make edits by selecting them.

We investigate two design tasks: precise adjustment and artistic exploration. We collect objective and subjective data, finding that subjects can perform equally well with physical and perceptual sliders as long as the interface responds interactively. Image navigation performs worse than the other interfaces on precise adjustment tasks, but excels at aiding in artistic exploration. We find that given enough time, novices can perform relatively complex material editing tasks with little training, and most novices work similarly to one another.
A simple geometric model for elastic deformations
Authors: Chao Isaac , Pinkall Ulrich , Sanan Patrick , Schröder Peter
Published: July 2010

We advocate a simple geometric model for elasticity:
distance between the differential of a deformation and the rotation group
. It comes with rigorous differential geometric underpinnings, both smooth and discrete, and is computationally almost as simple and efficient as linear elasticity. Owing to its geometric non-linearity, though, it does not suffer from the usual linearization artifacts. A material model with standard elastic moduli (Lamé parameters) falls out naturally, and a minimizer for static problems is easily augmented to construct a fully variational 2
nd
order time integrator. It has excellent conservation properties even for very coarse simulations, making it very robust.

Our analysis was motivated by a number of heuristic, physics-like algorithms from geometry processing (editing, morphing, parameterization, and simulation). Starting with a continuous energy formulation and taking the underlying geometry into account, we simplify and accelerate these algorithms while avoiding common pitfalls. Through the connection with the Biot strain of mechanics, the intuition of previous work that these ideas are "like" elasticity is shown to be spot on.
Unified simulation of elastic rods, shells, and solids
Authors: Martin Sebastian , Kaufmann Peter , Botsch Mario , Grinspun Eitan , Gross Markus
Published: July 2010

We develop an accurate, unified treatment of elastica. Following the method of resultant-based formulation to its logical extreme, we derive a higher-order integration rule, or
elaston
, measuring stretching, shearing, bending, and twisting along any axis. The theory and accompanying implementation do not distinguish between forms of different dimension (solids, shells, rods), nor between manifold regions and non-manifold junctions. Consequently, a single code accurately models a diverse range of elastoplastic behaviors, including buckling, writhing, cutting and merging. Emphasis on convergence to the continuum sets us apart from early unification efforts.
High-quality single-shot capture of facial geometry
Authors: Beeler Thabo , Bickel Bernd , Beardsley Paul , Sumner Bob , Gross Markus
Published: July 2010

This paper describes a passive stereo system for capturing the 3D geometry of a face in a single-shot under standard light sources. The system is low-cost and easy to deploy. Results are submillimeter accurate and commensurate with those from state-of-the-art systems based on active lighting, and the models meet the quality requirements of a demanding domain like the movie industry. Recovered models are shown for captures from both high-end cameras in a studio setting and from a consumer binocular-stereo camera, demonstrating scalability across a spectrum of camera deployments, and showing the potential for 3D face modeling to move beyond the professional arena and into the emerging consumer market in stereoscopic photography.

Our primary technical contribution is a modification of standard stereo refinement methods to capture pore-scale geometry, using a qualitative approach that produces visually realistic results. The second technical contribution is a calibration method suited to face capture systems. The systemic contribution includes multiple demonstrations of system robustness and quality. These include capture in a studio setup, capture off a consumer binocular-stereo camera, scanning of faces of varying gender and ethnicity and age, capture of highly-transient facial expression, and scanning a physical mask to provide ground-truth validation.
Paneling architectural freeform surfaces
Authors: Eigensatz Michael , Kilian Martin , Schiftner Alexander , Mitra Niloy J. , Pottmann Helmut , Pauly Mark
Published: July 2010

The emergence of large-scale freeform shapes in architecture poses big challenges to the fabrication of such structures. A key problem is the approximation of the design surface by a union of patches, so-called panels, that can be manufactured with a selected technology at reasonable cost, while meeting the design intent and achieving the desired aesthetic quality of panel layout and surface smoothness. The production of curved panels is mostly based on molds. Since the cost of mold fabrication often dominates the panel cost, there is strong incentive to use the same mold for multiple panels. We cast the major practical requirements for architectural surface paneling, including mold reuse, into a global optimization framework that interleaves discrete and continuous optimization steps to minimize production cost while meeting user-specified quality constraints. The search space for optimization is mainly generated through controlled deviation from the design surface and tolerances on positional and normal continuity between neighboring panels. A novel 6-dimensional metric space allows us to quickly compute approximate inter-panel distances, which dramatically improves the performance of the optimization and enables the handling of complex arrangements with thousands of panels. The practical relevance of our system is demonstrated by paneling solutions for real, cutting-edge architectural freeform design projects.
Triangle surfaces with discrete equivalence classes
Authors: Singh Mayank , Schaefer Scott
Published: July 2010

We propose a technique that takes a triangulated surface as input and outputs a surface with the same topology but altered geometry such that each polygon falls into a set of discrete equivalence classes. We begin by describing an error function that measures how close the polygons are to satisfying this criteria. To optimize this error function, we first cluster triangles into discrete sets such that the assignment of sets minimizes our error. We then find canonical polygons for each set using nonlinear optimization. Next, we solve a Poisson equation to find positions of vertices such that the surface polygons match the canonical polygons as close as possible. We also describe how to incorporate a fairness criteria into the optimization to avoid oscillations of the surface. We iterate this entire process until we reach a user specified tolerance, possibly adding clusters during iteration to guarantee convergence. We have been able to successfully reduce the number of unique triangles to lie within a small percentage of the total number of triangles in the surface and demonstrate our technique on various examples.
Matching fluid simulation elements to surface geometry and topology
Authors: Brochu Tyson , Batty Christopher , Bridson Robert
Published: July 2010

We introduce an Eulerian liquid simulation framework based on the Voronoi diagram of a potentially unorganized collection of pressure samples. Constructing the simulation mesh in this way allows us to place samples anywhere in the computational domain; we exploit this by choosing samples that accurately capture the geometry and topology of the liquid surface. When combined with high-resolution explicit surface tracking this allows us to simulate nearly arbitrarily thin features, while eliminating noise and other artifacts that arise when there is a resolution mismatch between the simulation and the surface---and allowing a precise inclusion of surface tension based directly on and at the same resolution as the surface mesh. In addition, we present a simplified Voronoi/Delaunay mesh velocity interpolation scheme, and a direct extension of embedded free surfaces and solid boundaries to Voronoi meshes.
Dynamic local remeshing for elastoplastic simulation
Authors: Wicke Martin , Ritchie Daniel , Klingner Bryan M. , Burke Sebastian , Shewchuk Jonathan R. , O'Brien James F.
Published: July 2010

We propose a finite element simulation method that addresses the full range of material behavior, from purely elastic to highly plastic, for physical domains that are substantially reshaped by plastic flow, fracture, or large elastic deformations. To mitigate artificial plasticity, we maintain a simulation mesh in both the current state and the rest shape, and store plastic offsets only to represent the non-embeddable portion of the plastic deformation. To maintain high element quality in a tetrahedral mesh undergoing gross changes, we use a dynamic meshing algorithm that attempts to replace as few tetrahedra as possible, and thereby limits the visual artifacts and artificial diffusion that would otherwise be introduced by repeatedly remeshing the domain from scratch. Our dynamic mesher also locally refines and coarsens a mesh, and even creates anisotropic tetrahedra, wherever a simulation requests it. We illustrate these features with animations of elastic and plastic behavior, extreme deformations, and fracture.
Camouflage images
Authors: Chu Hung-Kuo , Hsu Wei-Hsin , Mitra Niloy J. , Cohen-Or Daniel , Wong Tien-Tsin , Lee Tong-Yee
Published: July 2010

Camouflage images contain one or more hidden figures that remain imperceptible or unnoticed for a while. In one possible explanation, the ability to delay the perception of the hidden figures is attributed to the theory that human perception works in two main phases: feature search and conjunction search. Effective camouflage images make feature based recognition difficult, and thus force the recognition process to employ conjunction search, which takes considerable effort and time. In this paper, we present a technique for creating camouflage images. To foil the feature search, we remove the original subtle texture details of the hidden figures and replace them by that of the surrounding apparent image. To leave an appropriate degree of clues for the conjunction search, we compute and assign new tones to regions in the embedded figures by performing an optimization between two conflicting terms, which we call
immersion
and
standout
, corresponding to hiding and leaving clues, respectively. We show a large number of camouflage images generated by our technique, with or without user guidance. We have tested the quality of the images in an extensive user study, showing a good control of the difficulty levels.
A radiative transfer framework for rendering materials with anisotropic structure
Authors: Jakob Wenzel , Arbree Adam , Moon Jonathan T. , Bala Kavita , Marschner Steve
Published: July 2010

The radiative transfer framework that underlies all current rendering of volumes is limited to scattering media whose properties are invariant to rotation. Many systems allow for "anisotropic scattering," in the sense that scattered intensity depends on the scattering angle, but the standard equation assumes that the structure of the medium is isotropic. This limitation impedes physics-based rendering of volume models of cloth, hair, skin, and other important volumetric or translucent materials that do have anisotropic structure. This paper presents an end-to-end formulation of physics-based volume rendering of anisotropic scattering structures, allowing these materials to become full participants in global illumination simulations.

We begin with a generalized radiative transfer equation, derived from scattering by oriented non-spherical particles. Within this framework, we propose a new volume scattering model analogous to the well-known family of microfacet surface reflection models; we derive an anisotropic diffusion approximation, including the weak form required for finite element solution and a way to compute the diffusion matrix from the parameters of the scattering model; and we also derive a new anisotropic dipole BSSRDF for anisotropic translucent materials. We demonstrate results from Monte Carlo, finite element, and dipole simulations. All these contributions are readily implemented in existing rendering systems for volumes and translucent materials, and they all reduce to the standard practice in the isotropic case.
An artist friendly hair shading system
Authors: Sadeghi Iman , Pritchett Heather , Jensen Henrik Wann , Tamstorf Rasmus
Published: July 2010

Rendering hair in motion pictures is an important and challenging task. Despite much research on physically based hair rendering, it is currently difficult to benefit from this work because physically based shading models do not offer artist friendly controls. As a consequence much production work so far has used ad hoc shaders that are easier to control, but often lack the richness seen in real hair. We show that physically based shading models fail to provide intuitive artist controls and we introduce a novel approach for creating an art-directable hair shading model from existing physically based models. Through an informal user study we show that this system is easier to use compared to existing systems. Our shader has been integrated into the production pipeline at the Walt Disney Animation Studios and is being used in the production of the upcoming animated feature film Tangled.
Reliefs as images
Authors: Alexa Marc , Matusik Wojciech
Published: July 2010

We describe how to create relief surfaces whose diffuse reflection approximates given images under known directional illumination. This allows using any surface with a significant diffuse reflection component as an image display. We propose a discrete model for the area in the relief surface that corresponds to a pixel in the desired image. This model introduces the necessary degrees of freedom to overcome theoretical limitations in shape from shading and practical requirements such as stability of the image under changes in viewing condition and limited overall variation in depth. The discrete surface is determined using an iterative least squares optimization. We show several resulting relief surfaces conveying one image for varying lighting directions as well as two images for two specific lighting directions.
Micropolygon ray tracing with defocus and motion blur
Authors: Hou Qiming , Qin Hao , Li Wenyao , Guo Baining , Zhou Kun
Published: July 2010

We present a micropolygon ray tracing algorithm that is capable of efficiently rendering high quality defocus and motion blur effects. A key component of our algorithm is a BVH (bounding volume hierarchy) based on 4D hyper-trapezoids that project into 3D OBBs (oriented bounding boxes) in spatial dimensions. This acceleration structure is able to provide tight bounding volumes for scene geometries, and is thus efficient in pruning intersection tests during ray traversal. More importantly, it can exploit the natural coherence on the time dimension in motion blurred scenes. The structure can be quickly constructed by utilizing the micropolygon grids generated during micropolygon tessellation. Ray tracing of defocused and motion blurred scenes is efficiently performed by traversing the structure. Both the BVH construction and ray traversal are easily implemented on GPUs and integrated into a GPU-based micropolygon renderer. In our experiments, our ray tracer performs up to an order of magnitude faster than the state-of-art rasterizers while consistently delivering an image quality equivalent to a maximum-quality rasterizer. We also demonstrate that the ray tracing algorithm can be extended to handle a variety of effects, such as secondary ray effects and transparency.
A practical simulation of dispersed bubble flow
Authors: Kim Doyub , Song Oh-young , Ko Hyeong-Seok
Published: July 2010

In this paper, we propose a simple and efficient framework for simulating dispersed bubble flow. Instead of modeling the complex hydrodynamics of numerous small bubbles explicitly, our method approximates the average motion of these bubbles using a continuum multiphase solver. Then, the subgrid interactions among bubbles are computed using our new stochastic solver. Using the proposed scheme, we can efficiently simulate complex scenes with millions of bubbles.
A multi-layered display with water drops
Authors: Barnum Peter C. , Narasimhan Srinivasa G. , Kanade Takeo
Published: July 2010

We present a multi-layered display that uses water drops as voxels. Water drops refract most incident light, making them excellent wide-angle lenses. Each 2D layer of our display can exhibit arbitrary visual content, creating a layered-depth (2.5D) display. Our system consists of a single projector-camera system and a set of linear drop generator manifolds that are tightly synchronized and controlled using a computer. Following the principles of fluid mechanics, we are able to accurately generate and control drops so that, at any time instant, no two drops occupy the same projector pixel's line-of-sight. This drop control is combined with an algorithm for space-time division of projector light rays. Our prototype system has up to four layers, with each layer consisting of an row of 50 drops that can be generated at up to 60 Hz. The effective resolution of the display is 50x
projector vertical-resolution x number of layers.
We show how this water drop display can be used for text, videos, and interactive games.
NETRA
Authors: Pamplona Vitor F. , Mohan Ankit , Oliveira Manuel M. , Raskar Ramesh
Published: July 2010

We introduce an interactive, portable, and inexpensive solution for estimating refractive errors in the human eye. While expensive optical devices for automatic estimation of refractive correction exist, our goal is to greatly simplify the mechanism by putting the human subject in the loop. Our solution is based on a high-resolution programmable display and combines inexpensive optical elements, interactive GUI, and computational reconstruction. The key idea is to interface a lenticular view-dependent display with the human eye in
close range
- a few millimeters apart. Via this platform, we create a new range of interactivity that is extremely sensitive to parameters of the human eye, like refractive errors, focal range, focusing speed, lens opacity, etc. We propose several simple optical setups, verify their accuracy, precision, and validate them in a user study.
Star-contours for efficient hierarchical self-collision detection
Authors: Schvartzman Sara C. , Pérez Álvaro G. , Otaduy Miguel A.
Published: July 2010

Collision detection is a problem that has often been addressed efficiently with the use of hierarchical culling data structures. In the subproblem of self-collision detection for triangle meshes, however, such hierarchical data structures lose much of their power, because triangles adjacent to each other cannot be distinguished from actually colliding ones unless individually tested. Shape regularity of surface patches, described in terms of orientation and contour conditions, was proposed long ago as a culling criterion for hierarchical self-collision detection. However, to date, algorithms based on shape regularity had to trade conservativeness for efficiency, because there was no known algorithm for efficiently performing 2D contour self-intersection tests.

In this paper, we introduce a star-contour criterion that is amenable to hierarchical computations. Together with a thorough analysis of the tree traversal process in hierarchical self-collision detection, it has led us to novel hierarchical data structures and algorithms for efficient yet conservative self-collision detection. We demonstrate the application of our algorithm to several example animations, and we show that it consistently outperforms other approaches.