bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of placental transfusion in extremely low birthweight infants: meta‐analysis of long‐ and short‐term outcomes
Authors: Ghavam Sarvin , Batra Dushyant , Mercer Judith , Kugelman Amir , Hosono Shigeharu , Oh William , Rabe Heike , Kirpalani Haresh
Published: November 2013

Background

Risks and benefits of increasing placental transfusion in extremely preterm infants (extremely low birthweight [ELBW], <1000 g) are ill defined. We performed a meta‐analysis to compare long‐ and short‐term outcomes of ELBW infants in trials of enhanced placental transfusion regimens.

Study Design and Methods

We conducted a meta‐analysis of randomized controlled trials (RCTs) of delayed umbilical cord clamping or umbilical cord milking in compliance with PRISMA and Cochrane Collaborative guidelines for systematic reviews. We searched multiple databases for medical literature up to December 2012. Inclusion criteria were preterm infants less than 30 weeks and less than 1000 g birthweight, randomly assigned to enhanced placental transfusion (either delayed cord clamping or cord milking) versus immediate cord clamping. The primary outcome was standardized neurodevelopmental outcome at 18 to 24 months corrected age using a standardized scale. Several short‐term outcomes were also evaluated as secondary variables.

Results

We found 19 studies of which 10 studies could be included (n = 199). Three reported neurodevelopmental outcomes, none of which showed significant rates of disability. Two reported these at 18 to 24 months (n = 42) but used different scales preventing pooling. Short‐term benefits of enhanced placental strategies included better blood pressure and hemoglobin on admission, along with reduced blood transfusions, a trend to reduced intraventricular hemorrhage, and episodes of late‐onset sepsis.

Conclusions

Strategies to enhance placental transfusion may improve short‐term outcomes of ELBW infants. However, paucity of data on neurodevelopmental outcomes and safety concerns tempers enthusiasm for these interventions. Appropriately designed RCTs to assess short‐term and long‐term outcomes are needed in ELBW infants.
Isoprostane and isofuran lipid mediators accumulate in stored red blood cells and influence platelet function in vitro
Authors: Spinelli Sherry L. , Lannan Katie L. , Casey Ann E. , Croasdell Amanda , Curran Timothy M. , Henrichs Kelly F. , Pollock Stephen J. , Milne Ginger A. , Refaai Majed A. , Francis Charles W. , Phipps Richard P. , Blumberg Neil
Published: November 2013

Background

Stored red blood cells (RBCs) release hemoglobin (Hb) that leads to oxidative damage, which may contribute to thrombosis in susceptible transfusion recipients. Oxidative stress stimulates the generation of a new class of lipid mediators called F2‐isoprostanes (F2‐IsoPs) and isofurans (IsoFs) that influence cellular behavior. This study investigated RBC‐derived F2‐IsoPs and IsoFs during storage and their influence on human platelets (PLTs).

Study Design and Methods

F2‐IsoP and IsoF levels in RBC supernatants were measured by mass spectrometry during storage and after washing. The effects of stored supernatants, cell‐free Hb, or a key F2‐IsoP, 8‐iso‐prostaglandin F2α (PGF2α), on PLT function were examined in vitro.

Results

F2‐IsoPs, IsoFs, and Hb accumulated in stored RBC supernatants. Prestorage leukoreduction reduced supernatant F2‐IsoPs and IsoFs levels, which increased again over storage time. Stored RBC supernatants and 8‐iso‐PGF2α induced PLT activation marker CD62P (P‐selectin) expression and prothrombotic thromboxane A2 release. Cell‐free Hb did not alter PLT mediator release, but did inhibit PLT spreading. Poststorage RBC washing reduced F2‐IsoP and IsoF levels up to 24 hours.

Conclusions

F2‐IsoPs and IsoFs are produced by stored RBCs and induce adverse effects on PLT function in vitro, supporting a potential novel role for bioactive lipids in adverse transfusion outcomes. F2‐IsoP and IsoF levels could be useful biomarkers for determining the suitability of blood components for transfusion. A novel finding is that cell‐free Hb inhibits PLT spreading and could adversely influence wound healing. Poststorage RBC washing minimizes harmful lipid mediators, and its use could potentially reduce transfusion complications.
A novel approach for rapid detection of bacterially contaminated platelet concentrates via sensitive measurement of microbial DNA polymerase activity
Authors: Zweitzig Daniel R. , Riccardello Nichol M. , Pester John M. , Jeanmonod Rebecca , Kopnitsky Mark J. , O'Hara S. Mark
Published: November 2013

Background

Transfusion of bacterially contaminated platelet concentrates (PCs) can result in serious health consequences for the affected patient. Before being released from blood banking facilities, PCs are routinely screened for bacterial contamination by culture‐based tests. However, culture‐based PC screening methods require extended holding and incubation periods and are prone to false‐negative results due to sampling error. Screening PCs closer to the time of transfusion using rapid point‐of‐issue tests represents an alternative approach; however, FDA‐approved assays generally suffer from a lack of sensitivity.

Study Design and Methods

Presented herein is the feasibility of a novel approach toward rapid, sensitive, and universal detection of bacterially contaminated PCs via selective measurement of microbial DNA polymerase activity. This approach is achieved using a differential cell lysis procedure in combination with enzymatic template generation and amplification (termed ETGA‐PC assay).

Results

Serial dilution spiking experiments revealed an approximate sensitivity of 30 to 200 colony‐forming units (CFUs)/mL (mean, 85 CFUs/mL) for Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae. An additional 22 clinically relevant strains of bacteria were also detected below 200 CFUs/mL after spiking into PC aliquots. Furthermore, the ETGA‐PC assay was able to accurately monitor the presence and growth of seven clinically relevant bacterial species that were spiked into PC units.

Conclusion

Together, the data presented here demonstrate that the ETGA‐PC assay is a feasible approach for rapid and sensitive detection of bacterially contaminated PCs. Experiments, aimed at simplification and/or automation of the assay procedure, are under way.
The minimal generating sets of of size four
Authors: Jambor Sebastian
Published: November 2013

We show that there are only finitely many primes $p$ such that $\mathrm{PSL} (2, p)$ has a minimal generating set of size four.

Supplementary materials are available with this article.
Analysis of a Permselective Membrane-Free Alkaline Direct Ethanol Fuel Cell
Authors: Huang Jing , Bahrami Hafez , Faghri Amir
Published: November 2013

A physical model is developed to study the coupled mass and charge transport in a permselective membrane-free alkaline direct ethanol fuel cell. This type of fuel cell is not only free of expensive ion exchange membranes and platinum based catalysts, but also features a facile oxygen reduction reaction due to the presence of alkaline electrolyte. The proposed model is first validated by comparing its predictions to the experimental results from literature and then used to predict the overall performance of the cell and reveal the details of ion transport, distribution of electrolyte potential and current density. It is found that: (1) KOH concentration lower than 1 M notably impairs cell performance due to low electrolyte conductivity; (2) the concentration gradient and electrical field are equally important in driving ion transport in the electrolyte; (3) the current density distributions in the anode and cathode catalyst layers keep nonuniform due to different reasons. In the anode, it is caused by the ethanol concentration gradient, while in the cathode it is because of the electrolyte potential gradient; and (4) at low cell voltage, current density distribution in the catalyst layer shows stronger nonlinearity in the anode than in the cathode.
Dynamic Modeling of a Reformed Methanol Fuel Cell System Using Empirical Data and Adaptive Neuro-Fuzzy Inference System Models
Authors: Justesen Kristian K. , Andreasen Søren Juhl , Shaker Hamid Reza
Published: November 2013

In this work, a dynamic matlab Simulink model of an H3-350 reformed methanol fuel cell (RMFC) stand-alone battery charger produced by Serenergy® is developed on the basis of theoretical and empirical methods. The advantage of RMFC systems is that they use liquid methanol as a fuel instead of gaseous hydrogen, which is difficult and energy-consuming to store and transport. The models include thermal equilibrium models of the individual components of the system. Models of the heating and cooling of the gas flows between components are also modeled and adaptive neuro-fuzzy inference system models of the reforming process are implemented. Models of the cooling flow of the blowers for the fuel cell and the burner which supplies process heat for the reformer are made. The two blowers have a common exhaust, which means that the two blowers influence each other's output. The models take this into account using an empirical approach. Fin efficiency models for the cooling effect of the air are also developed using empirical methods. A fuel cell model is also implemented based on a standard model, which is adapted to fit the measured performance of the H3-350 module. All of the individual parts of the model are verified and fine-tuned through a series of experiments and are found to have mean absolute errors between 0.4% and 6.4% but typically below 3%. After a comparison between the performance of the combined model and the experimental setup, the model is deemed to be valid for control design and optimization purposes.
A Thermally Activated Drug Delivery System Based on a Thermoresponsive Polymer and a Cooling Device: A Theoretical Assessment
Authors: T. N. Vo Tuoi , Yang Rongbing , Aldabbagh Fawaz , Carroll William , Meere Martin , Rochev Yury
Published: November 2013

A mathematical model is developed to evaluate the feasibility of an in vivo implanted drug delivery system. The delivery device consists of a cooling material coated by a drug-loaded thermoresponsive polymeric film. Drug release is initiated by remotely dropping the temperature of the cooling material sufficiently for the temperature throughout the polymer coating to drop below its volume phase transition temperature (VPTT), causing the polymer to swell and release the drug. Drug release switches off again when heat conduction from an external fluid medium raises the polymer temperature to above the VPTT causing the polymer to collapse. Candidate cooling mechanisms based on endothermic chemical reactions, the Peltier effect, and the magnetocaloric effect is considered. In the thin polymer film limit, the model provides an upper bound for the temperature the cooling material must be lowered for drug release to be initiated. Significantly, the model predicts that the duration a thin polymer will continue to release drug in a single cycle is proportional to the square of the thickness of the cooling material. It is found that the system may be realized for realistic parameter values and materials. A simple illustrative calculation incorporating the presence of a heat source is presented, and the results suggest that conduction due to the initial temperature difference between the water and the cooling material can make the dominant contribution to heat transfer in the polymer as it reheats to its VPTT.
Motion and Strain Along the Musculotendon Junction of the Biceps Femoris: Shortening vs. Lengthening Contractions
Authors: Silder Amy , Thelen Darryl G.
Published: November 2013

Acute muscle strain injuries typically occur during active lengthening contractions, and tend to present along or near a musculotendon junction (MTJ) [1]. For example, among sprinters, the majority of hamstring strain injuries involve the proximal MTJ of the biceps femoris long head [1,2]. We have previously shown that post-injury scarring at the MTJ can persist for many months after return to sport [2], which may contribute to the high risk for re-injury associated with these injuries. Thus, it is pertinent to understand why the MTJ is susceptible to injury, and ultimately how post-injury remodeling may alter in-vivo mechanics. The purpose of the current study was to use dynamic magnetic resonance (MR) imaging to visualize muscle tissue displacements and mechanical strains during active lengthening contractions in the biceps femoris. We hypothesized that active lengthening contractions would induce greater mechanical strain along the proximal MTJ, when compared to shortening contractions of similar loads and ranges of motion.
Examining Quiet Standing Center of Pressure Data Using Invariant Density Analysis
Authors: Hur Pilwon , Shorter K. Alex , Hsiao-Wecksler Elizabeth T.
Published: November 2013

Posturographic data collected during quiet stance using force plates is widely used to assess postural stability [1]. Center of pressure (COP) is a commonly used experimental variable for several types of analyses. Traditionally, COP data have been analyzed using measures that describe the shape or speed of the trajectory [1]. Unfortunately, these parameters do not provide insight into the physiological system as a whole and have been shown to have questionable reliability [2].
Wall Shear Stress in Turbulent Pipe Flow
Authors: Gårdhagen Roland , Lantz Jonas , Carlsson Fredrik , Karlsson Matts
Published: November 2013

Low and/or oscillatory Wall Shear Stress (WSS) has been correlated with elevated risk for increased intima media thickness and atherosclerosis in several studies during the last decades [1, 2]. Most of the studies have addressed laminar flows, in which the oscillations mainly are due to the pulsating nature of blood flow. Turbulent flows however show significant spatial and temporal fluctuations although the mean flow is steady.
In Vivo Validation of Echo Partical Image Velocimetry (Echo PIV) in Human Carotid Arteries Using Phase-Contrast MRI
Authors: Zhang Fuxing , Barker Alex J. , Gates Phillip E. , Strain W. David , Fulford Jonathan , Mazzaro Luciano , Shore Angela C. , Bellenger Nick G. , Lanning Craig , Shandas Robin
Published: November 2013

Accurate non-invasive measurements of dynamic wall shear stresses (WSS) in the cardiovascular system should allow clinicians to evaluate the progression of atherosclerosis, estimate vulnerability of plaques, and assess hemodynamic changes in the proximity of implants such as vascular grafts and stents that may contribute to restenosis. Although computational methods have been used to obtain blood flow characteristics from patients, these methods are difficult to apply in routine fashion, are prone to errors due to incorrect application of boundary conditions and are time and resource intensive. Ultrasound Doppler methods [1] allow simple measurement of blood flow velocities but are not acceptable for shear measurements because they do not provide multiple-component velocity vectors, are prone to angulation error and have relatively poor spatial resolution. Phase contrast magnetic resonance imaging (PC-MRI) velocimetry [2] does provide good spatial resolution and multiple-component velocity vectors in vivo and is considered the gold-standard. However, PC-MRI is expensive, time consuming and possesses relatively poor temporal resolution.
Personalized Neuroprosthetics
Authors: Borton David , Micera Silvestro , Millán José del R. , Courtine Grégoire
Published: November 2013

Personalized neuroprosthetics is the synergy between accurate diagnosis, integrated development of neurotechnology, and patient-specific treatment design “to help the brain help itself” in nervous system disorders.
Fighting Blindness with Microelectronics
Authors: Zrenner Eberhart
Published: November 2013

Electronic retinal implants for treating inherited diseases of retinal degeneration have entered the clinic, but many hurdles remain to achieving full vision.
The Gut Microbiome Modulates Colon Tumorigenesis
Authors: Zackular Joseph P. , Baxter Nielson T. , Iverson Kathryn D. , Sadler William D. , Petrosino Joseph F. , Chen Grace Y. , Schloss Patrick D.
Published: November 2013

Recent studies have shown that individuals with colorectal cancer have an altered gut microbiome compared to healthy controls. It remains unclear whether these differences are a response to tumorigenesis or actively drive tumorigenesis. To determine the role of the gut microbiome in the development of colorectal cancer, we characterized the gut microbiome in a murine model of inflammation-associated colorectal cancer that mirrors what is seen in humans. We followed the development of an abnormal microbial community structure associated with inflammation and tumorigenesis in the colon. Tumor-bearing mice showed enrichment in operational taxonomic units (OTUs) affiliated with members of theBacteroides,Odoribacter, andAkkermansiagenera and decreases in OTUs affiliated with members of thePrevotellaceaeandPorphyromonadaceaefamilies. Conventionalization of germfree mice with microbiota from tumor-bearing mice significantly increased tumorigenesis in the colon compared to that for animals colonized with a healthy gut microbiome from untreated mice. Furthermore, at the end of the model, germfree mice colonized with microbiota from tumor-bearing mice harbored a higher relative abundance of populations associated with tumor formation in conventional animals. Manipulation of the gut microbiome with antibiotics resulted in a dramatic decrease in both the number and size of tumors. Our results demonstrate that changes in the gut microbiome associated with inflammation and tumorigenesis directly contribute to tumorigenesis and suggest that interventions affecting the composition of the microbiome may be a strategy to prevent the development of colon cancer.

IMPORTANCEThe trillions of bacteria that live in the gut, known collectively as the gut microbiome, are important for normal functioning of the intestine. There is now growing evidence that disruptive changes in the gut microbiome are strongly associated with the development colorectal cancer. However, how the gut microbiome changes with time during tumorigenesis and whether these changes directly contribute to disease have not been determined. We demonstrate using a mouse model of inflammation-driven colon cancer that there are dramatic, continual alterations in the microbiome during the development of tumors, which are directly responsible for tumor development. Our results suggest that interventions that target these changes in the microbiome may be an effective strategy for preventing the development of colorectal cancer.
Frequent Replenishment Sustains the Beneficial Microbiome of Drosophila melanogaster
Authors: Blum Jessamina E. , Fischer Caleb N. , Miles Jessica , Handelsman Jo
Published: November 2013

We report that establishment and maintenance of theDrosophila melanogastermicrobiome depend on ingestion of bacteria. Frequent transfer of flies to sterile food prevented establishment of the microbiome in newly emerged flies and reduced the predominant members,AcetobacterandLactobacillusspp., by 10- to 1,000-fold in older flies. Flies with a normal microbiome were less susceptible than germfree flies to infection bySerratia marcescensandPseudomonas aeruginosa. Augmentation of the normal microbiome with higher populations ofLactobacillus plantarum, aDrosophilacommensal and probiotic used in humans, further protected the fly from infection. Replenishment represents an unexplored strategy by which animals can sustain a gut microbial community. Moreover, the population behavior and health benefits ofL. plantarumresemble features of certain probiotic bacteria administered to humans. As such,L. plantarumin the fly gut may serve as a simple model for dissecting the population dynamics and mode of action of probiotics in animal hosts.

IMPORTANCEPrevious studies have defined the composition of theDrosophila melanogastermicrobiome in laboratory and wild-caught flies. Our study advances current knowledge in this field by demonstrating thatDrosophilamust consume bacteria to establish and maintain its microbiome. This finding suggests that the dominantDrosophilasymbionts remain associated with their host because of repeated reintroduction rather than internal growth. Furthermore, our study shows that one member of the microbiome,Lactobacillus plantarum, protects the fly from intestinal pathogens. These results suggest that, although not always present, the microbiota can promote salubrious effects for the host. In sum, our work provides a previously unexplored mechanism of microbiome maintenance and anin vivomodel system for investigating the mechanisms of action of probiotic bacteria.
Disappearance of An Adnexal Mass with Saam Acupuncture: A Case Report
Authors: Seo Jung Chul , Kwon Oh-Chang , Kwon Hyo-Jung , Chung Dae-Kyoo , Cho Yoon-Jeong , Lee Geon Ho
Published: November 2013

We report the case of a 30-year-old woman with a right adnexal mass resembling an ovarian cyst who declined diagnostic laparoscopy and requested treatment with acupuncture. The patient was treated with Saam acupuncture for 14 weeks. After treatment, transvaginal sonography revealed disappearance of the right adnexal mass. No adverse effects of the Saam acupuncture treatment were reported.
Impact of perioperative enteral synbiotics in hepatic and pancreatic surgery: design and rationale of a single blind placebo controlled prospective randomised control trial
Authors: Rammohan Ashwin , Sathyanesan Jeswanth , Rajendran Kamalakannan , Pitchaimuthu Anbalagan , Perumal Senthil Kumar , Srinivasan U P , Ramasamy Ravi , Palaniappan Ravichandran , Govindan Manoharan
Published: November 2013

Background

Prebiotics and probiotics influence all pathogenic mechanisms of bacterial translocation. Used in combination, they are called synbiotics. Postoperative infective complications in patients undergoing hepatic and pancreatic surgery lead to a significant prolongation of hospital stay and increased costs. While synbiotics are considered to have beneficial effects on human health, their clinical value in surgical patients, especially in South Asia remains unclear given a paucity of applicable clinical studies. In this study we aim to assess their clinical usefulness in patients who undergo hepatic and pancreatic surgery.

Methods

A prospective monocentric randomised single blind controlled trial is being conducted in patients undergoing major pancreatic resections (Whipple procedure, distal pancreatectomy, Frey procedure) and hepatic resections. Group A received a specific synbiotic composition, 5 days prior and 10 days after the surgery. Group B received a placebo. Primary study end point was the occurrence of postoperative infection during the first 30 days. Secondary outcome measures were mortality, first bowel movement, days in intensive care unit, length of hospital stay, and duration of antibiotic therapy. Side effects of probiotics were evaluated. From previous studies we assumed that perioperative synbiotics reduce the proportion of patients with infectious complications from 50% to 12%, with α of 0.05 and power 80%, the calculated sample size was 35 patients for each group with a dropout rate of 10%.

Conclusions

This study is intended at determining the impact of perioperative synbiotic therapy on postoperative infectious complications, morbidity and mortality in patients undergoing major pancreatic and hepatic surgery.

Clinical trial

The Clinical Trials Registry of India (CTRI/2013/06/003737).
He drove forward with a yell: anger in medicine and Homer
Authors: Bleakley A , Marshall R , Levine D
Published: November 2013

We use Homer and Sun Tzu as a background to better understand and reformulate confrontation, anger and violence in medicine, contrasting an unproductive ‘love of war’ with a productive ‘art of war’ or ‘art of strategy’. At first glance, it is a paradox that the healing art is not pacific, but riddled with militaristic language and practices. On closer inspection, we find good reasons for this cultural paradox yet regret its presence. Drawing on insights from Homer'sThe IliadandThe Odyssey, we argue for better understanding of confrontation, anger, bullying, intimidation and violence in medicine in order to change the culture. For example, equating medicine with war is not a given condition of medicine but a convenient metaphor with historical origins and a historical trajectory. Other, non-martial metaphors, such as medicine as collaboration, may be more appropriate in an age of team-based care. Taking lessons from Homer, we suggest three key ways in which cold-hearted confrontation and anger in medicine can be transformed into productive, warm-hearted engagement: the transformation of angry impulse into (1) reflection, (2) moral courage and (3) empathy. Thinking with Homer can offer an aesthetically and morally charged alternative to the current body of literature on topics, such as anger in doctors, and how this may be ‘managed’, without recourse to an instrumental economy where emotions are viewed as commodities, and emotional responses can be ‘trained’ through communication skills courses.
Winning the DARPA UAVForge Challenge 2012 — Team HALO
Authors: Prior S. D. , Shen S.-T. , Erbil M. A. , Brazinskas M. , Mielniczek W. P.
Published: November 2013

UAVForge was a Defense Advanced Research Projects Agency (DARPA) and Space and Naval Warfare Systems Center, Atlantic (SSC Atlantic) initiative to leverage the exchange of ideas among an international community united through common interests and inspired by creative thought. More than 140 teams and 3500 registered citizen scientists from 153 countries participated in this year long event. From several selection rounds, a core of nine teams competed in the fly-off event and in June 2012 Team HALO from the UK was declared the winner scoring 47.7 points out of a total of 60 points, with their co-axial tri-rotor, Y6 (VTOL) small Unmanned Aircraft System (sUAS).
Exploiting workload dynamics to improve SSD read latency via differentiated error correction codes
Authors: Wu Guanying , He Xubin , Xie Ningde , Zhang Tong
Published: November 2013

This article presents a cross-layer codesign approach to reduce SSD read response latency. The key is to cohesively exploit the NAND flash memory device write speed vs. raw storage reliability trade-off at the physical layer and runtime data access workload dynamics at the system level. Leveraging runtime data access workload variation, we can opportunistically slow down NAND flash memory write speed and hence improve NAND flash memory raw storage reliability. This naturally enables an opportunistic use of weaker error correction schemes that can directly reduce SSD read access latency. We develop a disk-level scheduling scheme to effectively smooth the write workload in order to maximize the occurrence of runtime opportunistic NAND flash memory write slowdown. Using 2 bits/cell NAND flash memory with BCH-based error correction correction as a test vehicle, we carry out extensive simulations over various workloads and demonstrate that this developed cross-layer co-design solution can reduce the average SSD read latency by up to 59.4% without sacrificing the write throughput performance.
An index-based management scheme with adaptive caching for huge-scale low-cost embedded flash storages
Authors: Huang Po-Chun , Chang Yuan-Hao , Kuo Tei-Wei
Published: November 2013

Due to its remarkable access performance, shock resistance, and costs, NAND flash memory is now widely adopted in a variety of computing environments, especially in mobile devices such as smart phones, media players and electronic book readers. For the consideration of costs, low-cost embedded flash storages such as flash memory cards are often employed on such devices. Different from solid-state disks, the RAM buffer equipped on low-cost embedded flash storages are very small, for example, limited under several dozens of kilobytes, despite of the rapidly growing capacity of the storages. The significance of effectively utilizing the very limited on-device RAM buffers of embedded flash storages is therefore highlighted, and a novel design of scalable flash management schemes is needed to tackle the new access constraints of MLC NAND flash memory. In this work, a highly scalable design of the flash translation layer is presented with the considerations of the on-device RAM size, user access patterns, address-mapping-information caching and MLC access constraints. Through a series of experiments, it is verified that, with appropriate settings of cache sizes, the proposed management scheme provides comparable performance results to prior arts with much lower requirements on the on-device RAM. In other words, the proposed scheme suggests a strategy to make better use of the on-device RAM, and is suitable for embedded flash storages.
Evaluating the distinctiveness and attractiveness of human motions on realistic virtual bodies
Authors: Hoyet Ludovic , Ryall Kenneth , Zibrek Katja , Park Hwangpil , Lee Jehee , Hodgins Jessica , O'Sullivan Carol
Published: November 2013

Recent advances in rendering and data-driven animation have enabled the creation of compelling characters with impressive levels of realism. While data-driven techniques can produce animations that are extremely faithful to the original motion, many challenging problems remain because of the high complexity of human motion. A better understanding of the factors that make human motion recognizable and appealing would be of great value in industries where creating a variety of appealing virtual characters with realistic motion is required. To investigate these issues, we captured thirty actors walking, jogging and dancing, and applied their motions to the same virtual character (one each for the males and females). We then conducted a series of perceptual experiments to explore the distinctiveness and attractiveness of these human motions, and whether characteristic motion features transfer across an individual's different gaits. Average faces are perceived to be less distinctive but more attractive, so we explored whether this was also true for body motion. We found that dancing motions were most easily recognized and that distinctiveness in one gait does not predict how recognizable the same actor is when performing a different motion. As hypothesized, average motions were always amongst the least distinctive and most attractive. Furthermore, as 50% of participants in the experiment were Caucasian European and 50% were Asian Korean, we found that the latter were as good as or better at recognizing the motions of the Caucasian actors than their European counterparts, in particular for dancing males, whom they also rated more highly for attractiveness.
Analyzing growing plants from 4D point cloud data
Authors: Li Yangyan , Fan Xiaochen , Mitra Niloy J. , Chamovitz Daniel , Cohen-Or Daniel , Chen Baoquan
Published: November 2013

Studying growth and development of plants is of central importance in botany. Current quantitative are either limited to tedious and sparse manual measurements, or coarse image-based 2D measurements. Availability of cheap and portable 3D acquisition devices has the potential to automate this process and easily provide scientists with volumes of accurate data, at a scale much beyond the realms of existing methods. However, during their development, plants grow new parts (e.g., vegetative buds) and bifurcate to different components --- violating the central incompressibility assumption made by existing acquisition algorithms, which makes these algorithms unsuited for analyzing growth. We introduce a framework to study plant growth, particularly focusing on accurate localization and tracking topological events like budding and bifurcation. This is achieved by a novel forward-backward analysis, wherein we track robustly detected plant components back in time to ensure correct spatio-temporal event detection using a locally adapting threshold. We evaluate our approach on several groups of time lapse scans, often ranging from days to weeks, on a diverse set of plant species and use the results to animate static virtual plants or directly attach them to physical simulators.
Image-based rendering in the gradient domain
Authors: Kopf Johannes , Langguth Fabian , Scharstein Daniel , Szeliski Richard , Goesele Michael
Published: November 2013

We propose a novel image-based rendering algorithm for handling complex scenes that may include reflective surfaces. Our key contribution lies in treating the problem in the gradient domain. We use a standard technique to estimate scene depth, but assign depths to image gradients rather than pixels. A novel view is obtained by rendering the horizontal and vertical gradients, from which the final result is reconstructed through Poisson integration using an approximate solution as a data term. Our algorithm is able to handle general scenes including reflections and similar effects
without
explicitly separating the scene into reflective and transmissive parts, as required by previous work. Our prototype renderer is fully implemented on the GPU and runs in real time on commodity hardware.
Content-adaptive image downscaling
Authors: Kopf Johannes , Shamir Ariel , Peers Pieter
Published: November 2013

This paper introduces a novel
content-adaptive
image downscaling method. The key idea is to optimize the shape and locations of the downsampling kernels to better align with local image features. Our content-adaptive kernels are formed as a bilateral combination of two Gaussian kernels defined over space and color, respectively. This yields a continuum ranging from smoothing to edge/detail preserving kernels driven by image content. We optimize these kernels to represent the input image well, by finding an output image from which the input can be well reconstructed. This is technically realized as an iterative maximum-likelihood optimization using a constrained variation of the Expectation-Maximization algorithm. In comparison to previous downscaling algorithms, our results remain crisper without suffering from ringing artifacts. Besides natural images, our algorithm is also effective for creating
pixel art
images from vector graphics inputs, due to its ability to keep linear features sharp
and
connected.
Real-time 3D reconstruction at scale using voxel hashing
Authors: Nießner Matthias , Zollhöfer Michael , Izadi Shahram , Stamminger Marc
Published: November 2013

Online 3D reconstruction is gaining newfound interest due to the availability of real-time consumer depth cameras. The basic problem takes live overlapping depth maps as input and incrementally fuses these into a single 3D model. This is challenging particularly when real-time performance is desired without trading quality or scale. We contribute an online system for large and fine scale volumetric reconstruction based on a memory and speed efficient data structure. Our system uses a simple spatial hashing scheme that compresses space, and allows for real-time access and updates of implicit surface data, without the need for a regular or hierarchical grid data structure. Surface data is only stored densely where measurements are observed. Additionally, data can be streamed efficiently in or out of the hash table, allowing for further scalability during sensor motion. We show interactive reconstructions of a variety of scenes, reconstructing both fine-grained details and large scale environments. We illustrate how all parts of our pipeline from depth map pre-processing, camera pose estimation, depth map fusion, and surface rendering are performed at real-time rates on commodity graphics hardware. We conclude with a comparison to current state-of-the-art online systems, illustrating improved performance and reconstruction quality.
Joint view expansion and filtering for automultiscopic 3D displays
Authors: Didyk Piotr , Sitthi-Amorn Pitchaya , Freeman William , Durand Frédo , Matusik Wojciech
Published: November 2013

Multi-view autostereoscopic displays provide an immersive, glasses-free 3D viewing experience, but they require correctly filtered content from multiple viewpoints. This, however, cannot be easily obtained with current stereoscopic production pipelines. We provide a practical solution that takes a stereoscopic video as an input and converts it to multi-view and filtered video streams that can be used to drive multi-view autostereoscopic displays. The method combines a phase-based video magnification and an interperspective antialiasing into a single filtering process. The whole algorithm is simple and can be efficiently implemented on current GPUs to yield a near real-time performance. Furthermore, the ability to retarget disparity is naturally supported. Our method is robust and works well for challenging video scenes with defocus blur, motion blur, transparent materials, and specularities. We show that our results are superior when compared to the state-of-the-art depth-based rendering methods. Finally, we showcase the method in the context of a real-time 3D videoconferencing system that requires only two cameras.
3-Sweep
Authors: Chen Tao , Zhu Zhe , Shamir Ariel , Hu Shi-Min , Cohen-Or Daniel
Published: November 2013

We introduce an interactive technique for manipulating simple 3D shapes based on extracting them from a single photograph. Such extraction requires understanding of the components of the shape, their projections, and relations. These simple cognitive tasks for humans are particularly difficult for automatic algorithms. Thus, our approach combines the cognitive abilities of humans with the computational accuracy of the machine to solve this problem. Our technique provides the user the means to quickly create editable 3D parts---human assistance implicitly segments a complex object into its components, and positions them in space. In our interface, three strokes are used to generate a 3D component that snaps to the shape's outline in the photograph, where each stroke defines one dimension of the component. The computer reshapes the component to fit the image of the object in the photograph as well as to satisfy various inferred geometric constraints imposed by its global 3D structure. We show that with this intelligent interactive modeling tool, the daunting task of object extraction is made simple. Once the 3D object has been extracted, it can be quickly edited and placed back into photos or 3D scenes, permitting object-driven photo editing tasks which are impossible to perform in image-space. We show several examples and present a user study illustrating the usefulness of our technique.
Saddle vertex graph (SVG)
Authors: Ying Xiang , Wang Xiaoning , He Ying
Published: November 2013

This paper presents the Saddle Vertex Graph (SVG), a novel solution to the discrete geodesic problem. The SVG is a sparse undirected graph that encodes complete geodesic distance information: a geodesic path on the mesh is equivalent to a shortest path on the SVG, which can be solved efficiently using the shortest path algorithm (e.g., Dijkstra algorithm). The SVG method solves the discrete geodesic problem from a local perspective. We have observed that the polyhedral surface has some interesting and unique properties, such as the fact that the discrete geodesic exhibits a strong local structure, which is not available on the smooth surfaces. The richer the details and complicated geometry of the mesh, the stronger such local structure will be. Taking advantage of the local nature, the SVG algorithm breaks down the discrete geodesic problem into significantly smaller sub-problems, and elegantly enables information reuse. It does not require any numerical solver, and is numerically stable and insensitive to the mesh resolution and tessellation. Users can intuitively specify a model-independent parameter
K
, which effectively balances the SVG complexity and the accuracy of the computed geodesic distance. More importantly, the computed distance is guaranteed to be a metric. The experimental results on real-world models demonstrate significant improvement to the existing approximate geodesic methods in terms of both performance and accuracy.
Anisotropic spherical Gaussians
Authors: Xu Kun , Sun Wei-Lun , Dong Zhao , Zhao Dan-Yong , Wu Run-Dong , Hu Shi-Min
Published: November 2013

We present a novelanisotropic Spherical Gaussian(ASG) function, built upon theBingham distribution[Bingham 1974], which is much more effective and efficient in representing anisotropic spherical functions than Spherical Gaussians (SGs). In addition to retaining many desired properties of SGs, ASGs are also rotationally invariant and capable of representing all-frequency signals. To further strengthen the properties of ASGs, we have derived approximate closed-form solutions for theirintegral, productandconvolutionoperators, whose errors are nearly negligible, as validated by quantitative analysis. Supported by all these operators, ASGs can be adapted in existing SG-based applications to enhance their scalability in handling anisotropic effects. To demonstrate the accuracy and efficiency of ASGs in practice, we have applied ASGs in two important SG-based rendering applications and the experimental results clearly reveal the merits of ASGs.
PolyCut
Authors: Livesu Marco , Vining Nicholas , Sheffer Alla , Gregson James , Scateni Riccardo
Published: November 2013

PolyCubes, or orthogonal polyhedra, are useful as parameterization base-complexes for various operations in computer graphics. However, computing quality PolyCube base-complexes for general shapes, providing a good trade-off between mapping distortion and singularity counts, remains a challenge. Our work improves on the state-of-the-art in PolyCube computation by adopting a graph-cut inspired approach. We observe that, given an arbitrary input mesh, the computation of a suitable PolyCube base-complex can be formulated as associating, or labeling, each input mesh triangle with one of six signed principal axis directions. Most of the criteria for a desirable PolyCube labeling can be satisfied using a multi-label graph-cut optimization with suitable
local
unary and pairwise terms. However, the highly constrained nature of PolyCubes, imposed by the need to align each chart with one of the principal axes, enforces additional
global
constraints that the labeling must satisfy. To enforce these constraints, we develop a constrained discrete optimization technique,
PolyCut
, which embeds a graph-cut multi-label optimization within a hill-climbing local search framework that looks for solutions that minimize the cut energy while satisfying the global constraints. We further optimize our generated PolyCube base-complexes through a combination of distortion-minimizing deformation, followed by a labeling update and a final PolyCube parameterization step. Our
PolyCut
formulation captures the desired properties of a PolyCube base-complex, balancing parameterization distortion against singularity count, and produces demonstrably better PolyCube base-complexes then previous work.
PiCam
Authors: Venkataraman Kartik , Lelescu Dan , Duparré Jacques , McMahon Andrew , Molina Gabriel , Chatterjee Priyam , Mullis Robert , Nayar Shree
Published: November 2013

We presentPiCam(Pelican Imaging Camera-Array), an ultra-thin high performance monolithic camera array, that captures light fields and synthesizes high resolution images along with a range image (scene depth) through integrated parallax detection and superresolution. The camera is passive, supporting both stills and video, low light capable, and small enough to be included in the next generation of mobile devices including smartphones. Prior works [Rander et al. 1997; Yang et al. 2002; Zhang and Chen 2004; Tanida et al. 2001; Tanida et al. 2003; Duparré et al. 2004] in camera arrays have explored multiple facets of light field capture - from viewpoint synthesis, synthetic refocus, computing range images, high speed video, and micro-optical aspects of system miniaturization. However, none of these have addressed the modifications needed to achieve the strict form factor and image quality required to make array cameras practical for mobile devices. In our approach, we customize many aspects of the camera array including lenses, pixels, sensors, and software algorithms to achieve imaging performance and form factor comparable to existing mobile phone cameras.

Our contributions to the post-processing of images from camera arrays include a cost function for parallax detection that integrates across multiple color channels, and a regularized image restoration (superresolution) process that takes into account all the system degradations and adapts to a range of practical imaging conditions. The registration uncertainty from the parallax detection process is integrated into a Maximum-a-Posteriori formulation that synthesizes an estimate of the high resolution image and scene depth. We conclude with some examples of our array capabilities such as postcapture (still) refocus, video refocus, view synthesis to demonstrate motion parallax, 3D range images, and briefly address future work.
An efficient construction of reduced deformable objects
Authors: von Tycowicz Christoph , Schulz Christian , Seidel Hans-Peter , Hildebrandt Klaus
Published: November 2013

Many efficient computational methods for physical simulation are based on model reduction. We propose new model reduction techniques for the
approximation of reduced forces
and for the
construction of reduced shape spaces of deformable objects
that accelerate the construction of a reduced dynamical system, increase the accuracy of the approximation, and simplify the implementation of model reduction. Based on the techniques, we introduce schemes for real-time simulation of deformable objects and interactive deformation-based editing of triangle or tet meshes. We demonstrate the effectiveness of the new techniques in different experiments with elastic solids and shells and compare them to alternative approaches.
Inverse bi-scale material design
Authors: Wu Hongzhi , Dorsey Julie , Rushmeier Holly
Published: November 2013

One major shortcoming of existing bi-scale material design systems is the lack of support for inverse design: there is no way to directly edit the large-scale appearance and then rapidly solve for the small-scale details that approximate that look. Prior work is either too slow to provide quick feedback, or limited in the types of small-scale details that can be handled. We present a novel computational framework for inverse bi-scale material design. The key idea is to convert the challenging inverse appearance computation into efficient search in two precomputed large libraries: one including a wide range of measured and analytical materials, and the other procedurally generated and height-map-based geometries. We demonstrate a variety of editing operations, including finding visually equivalent details that produce similar large-scale appearance, which can be useful in applications such as physical fabrication of materials.