bluuebunny/crossref_metadata_2025 huggingface dataset:
Residual layer uniformity using complementary patterns to compensate for pattern density variation in UV nanoimprint lithography
Authors: Wang Qing , Hiroshima Hiroshi , Atobe Hidemasa , Youn Sung-Won
Published: December 2010

How to form a thin and uniform residual layer, which is difficult to be created for a feature with nonuniform pattern densities, is of critical importance in nanoimprint lithography since residual layer removal by a reactive ion etching process will result in poor pattern transfer fidelity for nonuniform residual layers. A capacity-equalized mold using complementary cavity patterns to balance the imprinted volume of the feature with pattern density variation was verified to be a good method against pattern density variation for producing a uniform residual layer. To obtain an insight into the validity of the capacity-equalized mold, the effects of the introduced complementary patterns for capacity equalization on the residual layer, at locations that were not only at a distance away from the introduced complementary patterns but also the ones that were very close to the introduced complementary patterns, were carefully studied. It was found that a capacity-equalized mold with even very coarse complementary patterns as large as 10 times the minimum width of original patterns could result in a good uniform residual layer. It showed that the residual layer thickness was mainly determined by the volume of the capacity of the pattern trench with varied depths per unit area, but not by the size of the complementary patterns. Furthermore, the local nonuniformity induced by the complementary patterns themselves was also studied. The authors found that this local nonuniformity had little influence on producing a uniform residual layer that contributed to the low viscosity of the UV-curable resin. The authors also found that the nonuniformity of the residual layer was produced even by using a capacity-equalized mold due to the presence of air bubbles.
Moisture effect on electromigration characteristics for copper dual damascene interconnection
Authors: Cheng Yi-Lung , Chang Wei-Yuan , Wang Ying-Lang
Published: December 2010

The influence of moisture on Cu line electromigration (EM) behavior of dual damascene interconnection is reported. The authors have found that moisture has a negative influence on EM behavior, but it depends on the seal-ring structure located along the peripheral of the test pattern. The reduced Cu lifetime, observed for tested samples without seal-ring structure, was due to lateral moisture penetration. Lateral moisture diffusion was considered an effective mechanism for deteriorating the Cu interface during the die-sawing processing for structures without seal-ring layout. As a result, the seal-ring layout is effective and essential in Cu/low-dielectric (low-k) material integrity to prevent moisture penetration during the package procedures.
Nanofabrication of surface-enhanced Raman scattering device by an integrated block-copolymer and nanoimprint lithography method
Authors: Yang E. L. , Liu C. C. , Yang C. Y. P. , Steinhaus C. A. , Nealey P. F. , Skinner J. L.
Published: December 2010

The integration of block-copolymers (BCPs) and nanoimprint lithography (NIL) presents a novel and cost-effective approach to achieving nanoscale patterning capabilities. The authors demonstrate the fabrication of a surface-enhanced Raman scattering device using templates created by the BCP-NIL integrated method. The method utilizes a poly(styrene-block-methyl methacrylate) cylindrical-forming diblock-copolymer as a masking material to create a Si template, which is then used to perform a thermal imprint of a poly(methyl methacrylate) (PMMA) layer on a Si substrate. Au with a Cr adhesion layer was evaporated onto the patterned PMMA and the subsequent lift-off resulted in an array of nanodots. Raman spectra collected for samples of R6G on Si substrates with and without patterned nanodots showed enhancement of peak intensities due to the presence of the nanodot array. The demonstrated BCP-NIL fabrication method shows promise for cost-effective nanoscale fabrication of plasmonic and nanoelectronic devices.
Rapid patterning of spin-on-glass using ultrasonic nanoimprint
Authors: Mekaru Harutaka , Takahashi Masaharu
Published: December 2010

The authors succeeded in room-temperature patterning on a spin-on-glass (SOG) coated Si substrate by an ultrasonic nanoimprinting in a short duration of 1 min. Typically, at a room-temperature it takes a large press pressure and a long contact time to nanoimprint without a thermal pretreatment. In our ultrasonic nanoimprinting, a mold is attached directly to an ultrasonic generator, and mold patterns are set in motion at a high-speed in a direction aligned with the direction of the contact force applied. By this movement of mold patterns, plastic deformation and thermal deformation caused by the initial pressure and frictional heat generated by the ultrasonic vibration are combined to achieve precise structures. The authors had already confirmed the assisting effect of ultrasonic vibration at room-temperature nanoimprinting on various engineering plastics and baked SOG without any heating of mold. They then experimented to apply the ultrasonic nanoimprint method on nonbaked SOG coated substrates. They prepared an organic SOG and an inorganic SOG as molding materials, and executed ultrasonic nanoimprinting under various experimental conditions based on the optimized conditions for polyethylene terephthalate (frequency of ultrasonic vibration=10 kHz, contact force=500 N, and contact time=60 s). Moreover, the relationship between the amplitude of ultrasonic vibration and the imprinted depth was investigated, and the influence that the ultrasonic vibration exerted on the transfer accuracy of mold patterns was also determined.
Brightness limitations of cold field emitters caused by Coulomb interactions
Authors: Cook B. , Verduin T. , Hagen C. W. , Kruit P.
Published: December 2010

Emission theory predicts that high brightness cold field emitters can enhance imaging in the electron microscope. This (neglecting chromatic aberration) is because of the large (coherent) probe current available from a high brightness source and is based on theoretically determined values of reduced brightnesses up to 1014 A/(m2 sr V). However, in their analysis, the authors find that statistical Coulomb interactions limit the reduced brightness of even atomically sharp cold field emitters to 1011 A/(m2 sr V) and regular tungsten cold field emitters to around 2×108 A/(m2 sr V). The authors also find that for tip radii in the range from 5 nm to 1 μm, cold field emitters do not outperform larger Schottky (thermal field) emitters. Although this is applied to only one geometry, they expect that similar results will occur for most other cases due to a distinct difference in the behavior of different beam regimes.
Facile wide-scale defect detection of UV-nanoimprinted resist patterns by fluorescent microscopy
Authors: Kobayashi Kei , Kubo Shoichi , Matsui Shinji , Nakagawa Masaru
Published: December 2010

The occurrence of resist pattern defects in UV nanoimprinting with a spincoated resin thin film on a silicon wafer was studied by fluorescent microscopy using a fluorescent UV-curable liquid resin causing radical photopolymerization. The generation of nonfill defects with a surface-modified silica mold with submicrometer line cavities was compared between UV nanoimprinting atmospheres of air and pentafluoropropane. It was visualized in a rapid and nondestructive manner that nonfill defects were hardly induced by UV nanoimprinting under easily condensable pentafluoropropane atmosphere, while nonfill defects owing to bubble trap and resin adhesion to a mold surface were observed in the case of UV nanoimprinting under air atmosphere. The fluorescent microscopy using the fluorescent UV-curable resin was useful for mold inspection whether or not the submicrometer-scale mold cavities were partially filled with the resin. To investigate a resolution limit to nonfill defect, the authors examined a pattern pitch and a space width for convex resist line patterns in the line width range of 80–3000 nm with various ratios of space width to line width. Linear analysis of fluorescence intensity using fluorescent microscope images revealed that line pattern pitches with a space width of 0.30 μm could be detected by fluorescent microscopy. The 0.30 μm space width was almost consistent with a value calculated according to a Sparrow resolution limit.
Spectroscopic ellipsometry optical critical dimension measurements of templates and imprinted resist for patterned magnetic media applications
Authors: Yu Zhaoning , Hwu Justin , Liu Yongdong , Su Zhenpeng , Yang Henry , Wang Hongying , Hu Wei , Xu Yuan , Kurataka Nobuo , Hsu Yautzong , Lee Shifu , Gauzner Gene , Lee Kim , Kuo David
Published: December 2010

The authors have applied spectroscopic ellipsometry optical critical dimension (SE-OCD) measurement to grating templates and imprinted resist patterns with a pitch of 72.6 nm, corresponding to a track density of 350 ktpi (kilotracks per inch) for discreet track recording media. Their experiments indicate that SE-OCD is sensitive in detecting topography features in template profiles. The measurement of imprinted resist pattern is complicated by parameter correlation. Comparison of SE-OCD reported template and imprinted resist profiles can be used to study imprint pattern fidelity.
Reducing the pattern redundancy in optical proximity correction modeling by analyzing the pattern linearity
Authors: Li Jianliang , Zhang Lin , Yan Qiliang , Melvin Lawrence S. , Lin Chadwick , Su Eason , Tang Nail
Published: December 2010

In modern photolithography, optical proximity correction (OPC) has been widely adopted to improve the image fidelity of the mask on silicon wafer and, hence, improve the yield and the performance of integrated circuits. In recent years, model based optical proximity correction (MBOPC) has evolved from a nice-to-have feature to a must-have feature, especially, for the advanced nodes, 90 nm and beyond. The purpose of MBOPC is to adjust the designed pattern on the photomask to introduce mask perturbations, such that the layout printed on the wafer is as close as possible to the drawn layout. Before MBOPC is conducted on the full chip, a high quality and yet compact OPC model must be built, which simulates the photolithography process accurately. A high quality OPC model apparently relies on the quality of the empirical critical-dimension data in terms of both metrology noisiness and layout representativeness. Although more measurements on a large number of patterns will keep overall noise at lower levels and provide better input to OPC modeling, it is crucial to choose the representative patterns wisely and minimize the redundancy of gauges due to the limited metrology budget and the requirement of shortening turnaround time. In this article, the authors propose a method that checks the linear response of the optical signal on the one-dimensional (1D) patterns and selects the most representative patterns among all possible 1D structures.
Process-simulation system for UV-nanoimprint lithography
Authors: Shibata Mayuko , Horiba Akira , Nagaoka Yoshinori , Kawata Hiroaki , Yasuda Masaaki , Hirai Yoshihiko
Published: December 2010

Process-simulation systems for ultraviolet (UV) nanoimprint lithography are newly proposed to investigate process physics and resist profiles. The system consists of four modules, which simulate fluid dynamics in the resist-filling process into a pattern, the optical-intensity distribution in the UV exposure process, the mechanical properties in UV curing, and the resist profiles by UV shrinkage. Each module is independent, but shares physical parameters and resist profiles. Simulations on resist profiles by the UV curing process are demonstrated, taking the optical-intensity distribution into account. Also, a database model is newly introduced to simulate the resist profile due to shrinkage by UV curing.
Transmission electron microscopy study of damage layer formed through ion beam induced deposition of platinum on silicon substrate
Authors: Park Byong Chon , Park Yun Chang , Lee Hwack Joo , Kim Young Heon
Published: December 2010

Ion beam induced deposition is used for nanofabrication operations (e.g., transmission electron microscopy sample preparation) but is still not perfectly understood. Here, the authors describe the use of a wide variety of analytical instruments to develop such an understanding. Pt-films were deposited on native oxide films on silicon (Si) by decomposing trimethyl platinum C5H4CH3Pt(CH3)3 with focused electron or gallium ion beams. Unlike electron beam induced deposition, ion beam induced deposition produces a deep and complex damage layer below the deposition. It is revealed that the damaged area can be divided into three layers: (1) a “white-band” with a lower Pt-concentration and concurrent higher carbon (C)-concentration; (2) a-Pt–Si region where amorphized silicon crystal is mixed with Pt, and Pt-particle formation starts somewhere in the middle area; and (3) a-Si, which is silicon amorphized by Ga ions. The change in the diffusion rate of platinum into the amorphized silicon layer plays a crucial role in the formation of the distinct layers. The diffusions are affected by interatomic chemical affinity as well as by concentration, so that the Pt–Si combination initially dominates Pt agglomeration and the combination of C–Si, resulting in the creation of the novel white-band.
Rapid thermal imprinting of high-aspect-ratio nanostructures with dynamic heating of mold surface
Authors: Nagato Keisuke , Hattori Shuntaro , Hamaguchi Tetsuya , Nakao Masayuki
Published: December 2010

High-aspect-ratio nanostructures are thermally imprinted with dynamic heating of the mold surface. A thin-film current heater located at the back of the mold realized rapid heating, and an upper punch and a heater substrate as coolants make the cooling time short. This heater is applied to stamping-type imprinting and injection molding. The authors demonstrated imprinting nanostructures with aspect ratios of 2–3 in the cycle time of 15 s. This equipment concept is practical for high-throughput and low-energy thermal nanoimprinting.
Simulation of scanning electron microscope images taking into account local and global electromagnetic fields
Authors: Babin Sergey , Borisov Sergey S. , Ito Hiroyuki , Ivanchikov Andrei , Suzuki Makoto
Published: December 2010

The authors report the development of a simulation tool with unique capabilities to comprehensively model a scanning electron microscope (SEM) signal. This includes electron scattering, charging, and detector settings, as well as modeling of the local and global electromagnetic fields and electron trajectories in these fields. Experimental and simulated results were compared for SEM imaging of carbon nanofibers embedded into bulk material in the presence of significant charging as well as for samples with applied potential on metal electrodes. The effect of the potentials applied to electrodes on the secondary emission was studied; the resulting SEM images were simulated. The image contrast depends strongly on the sign and the value of the potential. SEM imaging of nanofibers embedded into silicon dioxide resulted in the considerable change in the apparent dimensions of the fibers as well as tone reversal when the beam voltage was varied. The results of the simulations are in agreement with experimental results.
Quantitative breast tomosynthesis: From detectability to estimability
Authors: Richard Samuel , Samei Ehsan
Published: December 2010

Purpose: This work aimed to extend Fourier‐based imaging metrics for modeling and predicting quantitative imaging performance. The new methodology was applied to the platform of breast tomosynthesis for investigating the influence of acquisition parameters (e.g., acquisition angle and dose) on quantitative imaging performance.

Methods: Two quantitative imaging tasks were considered: Area estimation and volume estimation of a 4 mm diameter spherical target. The maximum likelihood estimator yielded training data to generate a size estimation task function, which was combined with the MTF and NPS to predict estimation performance by computing an “estimability index” analogous to the detectability index. Estimation performance for the two tasks was computed as a function of acquisition angle and dose. The results were used for system optimization in terms of quantitation performance and further compared to the detectability index for the detection of the same spherical target.

Results: The estimability index computed with the size estimation tasks correlated well with precision measurements for area and volume estimation over a broad range of imaging conditions and provided a meaningful figure of merit for quantitative imaging performance and optimization. The results highlighted that optimal breast tomosynthesis acquisition parameters depend significantly on imaging task and dose. At nominal dose (1.5 mGy), mass detection was optimal at an acquisition angle of 85°, while area and volume estimation for the same mass were optimal at and 164° acquisition angles, respectively.

Conclusions: These findings provide an initial validation that the Fourier‐based metrics extended to estimation tasks can represent a meaningful metric and predictor of quantitative imaging performance. The optimization framework also revealed trade‐off between anatomical noise and system noise in volumetric imaging systems potentially identifying different optimal acquisition parameters than currently used in breast tomosynthesis and CT.
Reduction of dental filling metallic artifacts in CT‐based attenuation correction of PET data using weighted virtual sinograms optimized by a genetic algorithm
Authors: Abdoli Mehrsima , Ay Mohammad Reza , Ahmadian Alireza , Dierckx Rudi A. J. O. , Zaidi Habib
Published: December 2010

Purpose:

The presence of metallic dental fillings is prevalent in head and neck PET/CT imaging and generates bright and dark streaking artifacts in reconstructed CT images. The resulting artifacts would propagate to the corresponding PET images following CT‐based attenuation correction (CTAC). This would cause over‐ and/or underestimation of tracer uptake in corresponding regions thus leading to inaccurate quantification of tracer uptake. The purpose of this study is to improve our recently proposed metal artifact reduction (MAR) approach and to assess its performance in a clinical setting.

Methods:

The proposed MAR algorithm is performed in the virtual sinogram space to overcome the challenges associated with manipulating raw CT data. The corresponding bins of the virtual sinogram affected by metallic objects are obtained by forward projection of segmented metallic objects in the original CT image. These bins are then substituted by weighted values of three estimates: the affected bins in the original sinogram, the bins in the corrected sinogram using spline interpolation, and the sinogram bins in the neighboring column of the sinogram matrix. The optimized weighting factors (,, and) were estimated using a genetic algorithm (GA). The optimized combination of weighting coefficients was obtained using the GA applied to 24 clinical CT data sets. The proposed MAR method was then applied to 12 clinical head and neck PET/CT data sets containing dental artifacts. Analysis of the results was performed using Bland and Altman plots and a method allowing analysis in the absence of gold standard called regression without truth (RWT). The proposed method was also compared to an image‐based MAR method.

Results:

Optimization of the weighting coefficients using the GA resulted in an optimum combination of parameters of,, and. According to Bland and Altman plots generated for both CT and PET images of the clinical data, the proposed MAR algorithm is efficient for reduction of streak artifacts in CT images and such reduce the over‐ and/or underestimation of tracer uptake. The RWT method also confirmed the effectiveness of the proposed MAR method. The obtained figures of merit revealed that attenuation corrected PET data corrected using CTAC after applying the MAR algorithm are more similar to the assumed gold standard. Comparison with the knowledge‐based method revealed that the proposed method mainly corrects the artifactualregions without modifying the unaffected regions. The knowledge‐based method globally modifies the images including those that do not include metallic artifacts.

Conclusions:

The proposed MAR algorithm improves the quality and quantitative accuracy of clinical head and neck PET/CT images and could be easily integrated in clinical setting.
Optimal shielding design for bunkers of compact cyclotrons used in the production of medical radionuclides
Authors: Facure A. , França W. F.
Published: December 2010

Purpose:

There are several options to consider in the design of a vault that will house a cyclotron for radioisotopes production with regards to the door entrance. Alternatives are a direct‐shielded door, a simple maze, or a double‐legged maze. In this work, the impact of the neutron and photon doses at the vault entrance was evaluated for these options.

Methods:

Monte Carlo simulations were carried out in order to assess photon and neutron ambient dose equivalents. Simulations results were compared to experimental measurements taken inside a vault with a direct‐shielded door.

Results:

The double‐legged maze is the configuration that provides the higher degree of radiological protection at the vault entrance. In addition, the fact of the location of the cyclotron target plays an important role in the ambient dose equivalents.

Conclusions:

The comparison performed between measurements and results ofMCNP simulations confirmed a favorable agreement; maze legs reduce the neutron energies at the entrances of the vault. However, a degree of dose reduction similar to the one obtained for a two‐legged maze can be achieved with the addition of shielding against neutrons in the inner maze entrance to act as a second door. A choice of a vault design is more evident by comparing the results of this study.
A method of estimating conceptus doses resulting from multidetector CT examinations during all stages of gestation
Authors: Damilakis John , Tzedakis Antonis , Perisinakis Kostas , Papadakis Antonios E.
Published: December 2010

Purpose:

Current methods for the estimation of conceptus dose from multidetector CT (MDCT) examinations performed on the mother provide dose data for typical protocols with a fixed scan length. However, modified low‐dose imaging protocols are frequently used during pregnancy. The purpose of the current study was to develop a method for the estimation of conceptus dose from any MDCT examination of the trunk performed during all stages of gestation.

Methods:

The Monte Carlo N‐Particle (MCNP) radiation transport code was employed in this study to model the Siemens Sensation 16 and Sensation 64 MDCT scanners. Four mathematical phantoms were used, simulating women at 0, 3, 6, and 9 months of gestation. The contribution to the conceptus dose from single simulated scans was obtained at various positions across the phantoms. To investigate the effect of maternal body size and conceptus depth on conceptus dose, phantoms of different sizes were produced by adding layers of adipose tissue around the trunk of the mathematical phantoms. To verify MCNP results, conceptus dose measurements were carried out by means of three physical anthropomorphic phantoms, simulating pregnancy at 0, 3, and 6 months of gestation and thermoluminescence dosimetry (TLD) crystals.

Results:

The results consist of Monte Carlo‐generated normalized conceptus dose coefficients for single scans across the four mathematical phantoms. These coefficients were defined as the conceptus dose contribution from a single scan divided by the CTDI free‐in‐air measured with identical scanning parameters. Data have been produced to take into account the effect of maternal body size and conceptus position variations on conceptus dose. Conceptus doses measured with TLD crystals showed a difference of up to 19% compared to those estimated by mathematical simulations.

Conclusions:

Estimation of conceptus doses from MDCT examinations of the trunk performed on pregnant patients during all stages of gestation can be made using the method developed in the current study.
Failure mode and effect analysis‐based quality assurance for dynamic MLC tracking systems
Authors: Sawant Amit , Dieterich Sonja , Svatos Michelle , Keall Paul
Published: December 2010

Purpose:

To develop and implement a failure mode and effect analysis (FMEA)‐based commissioning and quality assurance framework for dynamic multileaf collimator (DMLC) tumor tracking systems.

Methods:

A systematic failure mode and effect analysis was performed for a prototype real‐time tumor tracking system that uses implanted electromagnetic transponders for tumor position monitoring and a DMLC for real‐time beam adaptation. A detailed process tree of DMLC tracking delivery was created and potential tracking‐specific failure modes were identified. For each failure mode, a risk probability number (RPN) was calculated from the product of the probability of occurrence, the severity of effect, and the detectibility of the failure. Based on the insights obtained from the FMEA, commissioning and QA procedures were developed to check (i) the accuracy of coordinate system transformation, (ii) system latency, (iii) spatial and dosimetric delivery accuracy, (iv) delivery efficiency, and (v) accuracy and consistency of system response to error conditions. The frequency of testing for each failure mode was determined from the RPN value.

Results:

Failures modes with were recommended to be tested monthly. Failure modes with were assigned to be tested during comprehensive evaluations, e.g., during commissioning, annual quality assurance, and after major software/hardware upgrades. System latency was determined to be . The system showed consistent and accurate response to erroneous conditions. Tracking accuracy was within 3%–3 mm gamma (100% pass rate) for sinusoidal as well as a wide variety of patient‐derived respiratory motions. The total time taken for monthly QA was , while that taken for comprehensive testing was .

Conclusions:

FMEA proved to be a powerful and flexible tool to develop and implement a quality management (QM) framework for DMLC tracking. The authors conclude that the use of FMEA‐based QM ensures efficient allocation of clinical resources because the most critical failure modes receive the most attention. It is expected that the set of guidelines proposed here will serve as a living document that is updated with the accumulation of progressively more intrainstitutional and interinstitutional experience with DMLC tracking.
An automatic and accurate x‐ray tube focal spot/grid alignment system for mobile radiography: System description and alignment accuracya)
Authors: Gauntt David M. , Barnes Gary T.
Published: December 2010

Purpose:

A mobile radiography automatic grid alignment system (AGAS) has been developed by modifying a commercially available mobile unit. The objectives of this article are to describe the modifications and operation and to report on the accuracy with which the focal spot is aligned to the grid and the time required to achieve the alignment.

Methods:

The modifications include an optical target arm attached to the grid tunnel, a video camera attached to the collimator, a motion control system with six degrees of freedom to position the collimator and x‐ray tube, and a computer to control the system. The video camera and computer determine the grid position, and then the motion control system drives the x‐ray focal spot to the center of the grid focal axis. The accuracy of the alignment of the focal spot with the grid and the time required to achieve alignment were measured both in laboratory tests and in clinical use.

Results:

For a typical exam, the modified unit automatically aligns the focal spot with the grid in less than 10 s, with an accuracy of better than 4 mm. The results of the speed and accuracy tests in clinical use were similar to the results in laboratory tests. Comparison patient chest images are presented—one obtained with a standard mobile radiographic unit without a grid and the other obtained with the modified unit and a 15:1 grid. The 15:1 grid images demonstrate a marked improvement in image quality compared to the nongrid images with no increase in patient dose.

Conclusions:

The mobile radiography AGAS produces images of significantly improved quality compared to nongrid images with alignment times of less than 10 s and no increase in patient dose.
Promoting Apoptosis
Authors: Ray L. Bryan
Published: December 2010

The promyelocytic leukemia protein likely influences apoptosis by influencing a calcium channel in the endoplasmic reticulum.
IL-22
+
CD4
+
T Cells Are Associated with Therapeutic
Trichuris trichiura
Infection in an Ulcerative Colitis Patient
Authors: Broadhurst Mara J. , Leung Jacqueline M. , Kashyap Vikram , McCune Joseph M. , Mahadevan Uma , McKerrow James H. , Loke P’ng
Published: December 2010

IL-22
+
CD4
+
cells are associated with
Trichuris trichiura
infection in an ulcerative colitis patient.
Human Cytomegalovirus Tegument Protein pUL71 Is Required for Efficient Virion Egress
Authors: Womack Andrew , Shenk Thomas
Published: December 2010

The human cytomegalovirus virion is composed of a DNA genome packaged in an icosahedral capsid, surrounded by a tegument of protein and RNA, all enclosed within a glycoprotein-studded envelope. Achieving this intricate virion architecture requires a coordinated process of assembly and egress. We show here that pUL71, a component of the virion tegument with a previously uncharacterized function, is required for the virus-induced reorganization of host cell membranes, which is necessary for efficient viral assembly and egress. A mutant that did not express pUL71 was able to efficiently accumulate viral genomes and proteins that were tested but was defective for the production and release of infectious virions. The protein localized to vesicular structures at the periphery of the viral assembly compartment, and during infection with a pUL71-deficient virus, these structures were grossly enlarged and aberrantly contained a cellular marker of late endosomes/lysosomes. Mutant virus preparations exhibited less infectivity per unit genome than wild-type virus preparations, due to aggregation of virus particles and their association with membrane fragments. Finally, mutant virus particles accumulated within the cytoplasm of infected cells and were localized to the periphery of large structures with properties of lysosomes, whose formation was kinetically favored in mutant-virus-infected cells. Together, these observations point to a role for pUL71 in the establishment and/or maintenance of a functional viral assembly compartment that is required for normal virion trafficking and egress from infected cells.

IMPORTANCE
In addition to causing disease in immunocompromised individuals, human cytomegalovirus is the leading known infectious cause of birth defects. To induce these pathologies, the virus must spread from its site of introduction to various organs and tissues in the body. The processes of viral assembly and egress, which underlie the spread of infection, are incompletely understood. We elucidate a role for a virus-coded protein, pUL71, in these processes and demonstrate the importance of maintaining an intricate, virus-induced reorganization of host cell membranes for efficient virus spread.
Intrinsic risk factors of non-contact quadriceps and hamstring strains in soccer: a prospective study of 100 professional players
Authors: Fousekis Konstantinos , Tsepis Elias , Poulmedis Peter , Athanasopoulos Spyros , Vagenas George
Published: December 2010

Objectives

To identify the intrinsic risk factors of non-contact strains in the hamstrings and quadriceps muscles of professional soccer players via a cohort prospective design.

Methods

A total of 100 professional soccer players (aged 19.4–27.8 years) from four professional teams underwent a composite musculoskeletal assessment at preseason. Intrinsic risk factors included dichotomies of asymmetries in muscle strength, flexibility, proprioception, anthropometry and knee joint stability, and of previous injuries. Muscle strains were prospectively monitored during the subsequent season using questionnaires. The data were analysed via binary logistic regression.

Results

Thirty-eight percent of the players sustained one or more lower-extremity muscle strains. Sixteen (42.1 %) and seven (18.4 %) of them were clinically diagnosed as having non-contact muscle strains at their hamstrings and quadriceps, respectively. Players with eccentric hamstring strength asymmetries (OR=3.88; 95% CI 1.13 to 13.23), functional leg length asymmetries (OR=3.80; 95% CI 1.08 to 13.33) and no previous hamstrings injuries (OR=0.15; 95% CI 0.029 to 0.79) were at greater risk of sustaining a hamstring muscle strain. Players with eccentric strength (OR=5.01; 95% CI 0.92 to 27.14) and flexibility asymmetries (OR=4.98; 95% CI 0.78 to 31.80) in their quadriceps as well as heavier (OR=10.70; 95% CI 0.73 to 156.37) and shorter players (OR=0.08; 95% CI 0.00 to 1.35) were at greater risk of sustaining a strain in this muscle group.

Conclusions

Professional soccer players with functional asymmetries possess a higher risk of sustaining hamstring strains. Previous injury seems not to constitute a risk factor. The systematic isokinetic evaluation of the lower extremities during the preseason period can provide therapists and trainers with valuable data regarding the predictive elements of non-contact hamstring strains in professional soccer players.
PULSATILE FLOW AND HEAT TRANSFER OF A MAGNETO-MICROPOLAR FLUID THROUGH A STENOSED ARTERY UNDER THE INFLUENCE OF BODY ACCELERATION
Authors: SHIT G. C. , ROY M.
Published: December 2010

With an aim to investigate the effect of externally imposed body acceleration and magnetic field on pulsatile flow of blood through an arterial segment having stenosis is under consideration in this article. The flow of blood is presented by an unsteady micropolar fluid, and the heat-transfer characteristics have been taken into account. The nonlinear equations that govern the flow are solved numerically using finite difference technique by employing a suitable coordinate transformation. The numerical results have been observed for axial and microrotation component of velocity, fluid acceleration, wall shear stress (WSS), flow resistance, temperature, and the volumetric flow rate. It thus turns out that the rate of heat transfer increases with the increase of Hartmann number H, while the WSS has a reducing effect on the Hartmann number H and an enhancing effect on the ratio of viscosity K as well as on the constriction height δ.
ANALYTICAL AND NUMERICAL SOLUTIONS OF PERISTALTIC FLOW OF WILLIAMSON FLUID MODEL IN AN ENDOSCOPE
Authors: AKBAR NOREEN SHER , NADEEM S.
Published: December 2010

The present studies deal with the peristaltic motion of an incompressible Williamson fluid model in an endoscope. The governing equations of Williamson fluid model are first simplify using the assumptions of long wavelength and low Reynolds number. The four types of solutions have been presented for velocity profile named (i) exact solution, (ii) perturbation solution, (iii) HAM solution, and (iv) numerical solutions. The comparisons of four solutions have been found a very good agreement between all the solutions. In addition, the expressions for pressure rise and velocity against various physical parameters are discussed through graphs.
MOLECULAR DYNAMICS SIMULATION OF ADSORPTION OF ANILINE BY α-ZIRCONIUM PHOSPHATE
Authors: CHEN RUO-YU , ZHONG JING , GU CHI-RUEI , CHEN CHENG-LUNG
Published: December 2010

Molecular dynamics simulation and minimization process were carried out to study the structure properties of α-zirconium phosphate (α- ZrP ) loaded with aniline molecules. Two minimum-energy configurations of α- ZrP with interlayer distances 14.14 and 19.0 Å were found for the systems of molar ratios of aniline to ZrP = 1:1 and 2:1. The structure properties of aniline and α- ZrP and also the interaction between aniline and α- ZrP were analyzed. The phase behavior was analyzed by calculated diffraction patterns, power spectra, and various distribution functions.
THE STEREODYNAMICS STUDY OF THEC(3P) +OH(X2Π) →CO(X1Σ+) +H(2S) REACTION
Authors: SONG PENG , ZHU YONG-HUA , LIU JIAN-YONG , MA FENG-CAI
Published: December 2010

The stereodynamics of the title reaction on the ground electronic state X2A' potential energy surface (PES)1has been studied using the quasiclassical trajectory (QCT) method. The commonly used polarization-dependent differential cross-sections (PDDCSs) of the product and the angular momentum alignment distribution, P(θr) and P(Φr), are generated in the center-of-mass frame using QCT method to gain insight of the alignment and orientation of the product molecules. Influence of collision energy on the stereodynamics is shown and discussed. The results reveal that the distribution of P(θr) and P(Φr) is sensitive to collision energy. The PDDCSs exhibit different collision energy dependency relationship at low and high collision energy ranges.
vGreen
Authors: Dhiman Gaurav , Marchetti Giacomo , Rosing Tajana
Published: December 2010

In this article, we present vGreen, a multitiered software system for energy-efficient virtual machine management in a clustered virtualized environment. The system leverages the use of novel hierarchical metrics that work across the different abstractions in a virtualized environment to capture power and performance characteristics of both the virtual and physical machines. These characteristics are then used to implement policies for scheduling and power management of virtual machines across the cluster. We show through real implementation of the system on a state-of-the-art testbed of server machines that vGreen improves both average performance and system-level energy savings by close to 40% across benchmarks with varying characteristics.
Energy-Efficient Progressive Remote Update for Flash-Based Firmware of Networked Embedded Systems
Authors: Kim Jinsik , Chou Pai H.
Published: December 2010

Firmware update over a network connection is an essential but expensive feature for many embedded systems due to not only the relatively high power consumption and limited bandwidth, but also page-granular erasure before rewriting to flash memory. This work proposes a page-level, link-time technique that minimizes not only the size of patching scripts but also perturbation to the firmware memory, over the entire sequence of updates in the system’s lifetime. We propose a tool that first clusters functions to minimize caller-callee dependency across pages, and then orders the functions within each page to minimize intrapage perturbation. Experimental results show our technique to reduce the energy consumption of firmware update by 30--42% over the state-of-the-art. Most importantly, this is the first work that has ever shown to evolve well over 41 revisions of a real-world open-source real-time operating system.
Computer vision based guidance in UAVs
Authors: Bhat Shubha , Malagi Vindhya , Rangarajan Krishnan , Babu Ramesh
Published: December 2010

In this paper we discuss the key functional and quality attribute requirements and the associated design challenges in engineering a computer vision guided UAV (Unmanned Aerial Vehicle) system. The non-functional requirements of the UAV system as a wholeare identified and mapped to the computer vision subsystem which aids in the navigation process. Expectations on availability, reliability, performance, security and evolution of the vision subsystemare discussed and the related software design challenges elaborated
Towards the design of a set-based Java collections framework
Authors: Long Brad
Published: December 2010

The Java Collections Framework (JCF) was introduced as standard in JDK 1.2. Since then several significant enhancements have been made including the introduction of generics and typed collections. One striking design choice of the Java language designers was the exclusion of map from the collections hierarchy. This paper looks at how maps could be incorporated into the Java collections hierarchy by describing early work on YACL (Yet Another Collections Library). The intention of YACL is to provide a suite of set-based collections classes and operations whilst continuing to be compatible with the JCF
An approach for early prediction of software reliability
Authors: Mohanta Sirsendu , Vinod Gopika , Ghosh A. K. , Mall Rajib
Published: December 2010

In the early stages of development, failure information is not available to quantitatively measure reliability of a software product. In this context, we propose an approach to predict software reliability early in the product development stages from design metrics. First we predict reliabilities of the components of a system. For this, we categorize the different kinds of faults that can occur in a component during its development and identify the design metrics that correlate to these faults. We construct a Bayesian Belief Network (BBN) model to predict reliabilities of the components using the identified design metrics. Based on predicted reliabilities and usage frequencies of the components of a system, we determine the reliability of the system. The applicability of our proposed model is illustrated through a case study. Results obtained from our case study indicate the effectiveness of our approach
Model-based regression test case prioritization
Authors: Panigrahi Chhabi Rani , Mall Rajib
Published: December 2010

We propose a model-based regression test case prioritization technique for object-oriented programs. Our technique involves constructing a graph model of the source code to represent control and data dependences as well as static object relations such as inheritance, aggregation and association. We construct a forward slice of the model to identify all the model elements that may be affected by a change. Subsequently, the model elements are marked with the specific test case(s) testing it. We construct backward slice with respect to each model element executed by a test case to determine all elements indirectly tested by the test case. Then all the affected model elements and the elements being tested are used to prioritize test cases. Empirical studies carried out by us show that our technique increases the detection of number of faults on an average of 30 percent as compared to traditional approaches in detecting regression errors
Motion fields for interactive character locomotion
Authors: Lee Yongjoon , Wampler Kevin , Bernstein Gilbert , Popović Jovan , Popović Zoran
Published: December 2010

We propose a novel representation of motion data and control that enables characters with both highly agile responses to user input and natural handling of arbitrary external disturbances. The representation organizes motion data as samples in a high dimensional generalization of a vector field we call a 'motion field'. Our runtime motion synthesis mechanism freely 'flows' in the motion field and is capable of creating novel and natural motions that are highly-responsive to the real time user input, and generally not explicitly specified in the data.
Morphable crowds
Authors: Ju Eunjung , Choi Myung Geol , Park Minji , Lee Jehee , Lee Kang Hoon , Takahashi Shigeo
Published: December 2010

Crowd simulation has been an important research field due to its diverse range of applications that include film production, military simulation, and urban planning. A challenging problem is to provide simple yet effective control over captured and simulated crowds to synthesize intended group motions. We present a new method that blends existing crowd data to generate a new crowd animation. The new animation can include an arbitrary number of agents, extends for an arbitrary duration, and yields a natural-looking mixture of the input crowd data. The main benefit of this approach is to create new spatio-temporal crowd behavior in an intuitive and predictable manner. It is accomplished by introducing a morphable crowd model that allows us to encode the formations and individual trajectories in crowd data. Then, its original spatio-temporal behavior can be reconstructed and interpolated at an arbitrary scale using our morphable model.
A progressive error estimation framework for photon density estimation
Authors: Hachisuka Toshiya , Jarosz Wojciech , Jensen Henrik Wann
Published: December 2010

We present an error estimation framework for progressive photon mapping. Although estimating rendering error has been established for unbiased rendering algorithms, error estimation for biased rendering algorithms has not been investigated well in comparison. We characterize the error by the sum of a bias estimate and a stochastic noise bound, which is motivated by stochastic error bounds formulation in biased methods. As a part of our error computation, we extend progressive photon mapping to operate with smooth kernels. This enables the calculation of illumination gradients with arbitrary accuracy, which we use to progressively compute the local bias in the radiance estimate. We also show how variance can be computed in progressive photon mapping, which is used to estimate the error due to noise. As an example application, we show how our error estimation can be used to compute images with a given error threshold. For this example application, our framework only requires the error threshold and a confidence level to automatically terminate rendering. Our results demonstrate how our error estimation framework works well in realistic synthetic scenes.
Data-driven image color theme enhancement
Authors: Wang Baoyuan , Yu Yizhou , Wong Tien-Tsin , Chen Chun , Xu Ying-Qing
Published: December 2010

It is often important for designers and photographers to convey or enhance desired color themes in their work. A color theme is typically defined as a template of colors and an associated verbal description. This paper presents a data-driven method for enhancing a desired color theme in an image. We formulate our goal as a unified optimization that simultaneously considers a desired color theme, texture-color relationships as well as automatic or user-specified color constraints. Quantifying the difference between an image and a color theme is made possible by color mood spaces and a generalization of an additivity relationship for two-color combinations. We incorporate prior knowledge, such as texture-color relationships, extracted from a database of photographs to maintain a natural look of the edited images. Experiments and a user study have confirmed the effectiveness of our method.
MovieReshape
Authors: Jain Arjun , Thormählen Thorsten , Seidel Hans-Peter , Theobalt Christian
Published: December 2010

We present a system for quick and easy manipulation of the body shape and proportions of a human actor in arbitrary video footage. The approach is based on a morphable model of 3D human shape and pose that was learned from laser scans of real people. The algorithm commences by spatio-temporally fitting the pose and shape of this model to the actor in either single-view or multi-view video footage. Once the model has been fitted, semantically meaningful attributes of body shape, such as height, weight or waist girth, can be interactively modified by the user. The changed proportions of the virtual human model are then applied to the actor in all video frames by performing an image-based warping. By this means, we can now conveniently perform spatio-temporal reshaping of human actors in video footage which we show on a variety of video sequences.