bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Study on Thrust Generation Performance of Plunging Airfoils
Authors: Gao Ji , Yuan Rui Shan , Zhang Ming Hui , Xie Yong Hui
Published: March 2013

In this paper, the effects of angle of attack, camber and camber location on propulsion performance of flapping airfoils undergoing plunging motion were numerically studied at Re=20000 and h=0.175. The unsteady incompressible viscous flow around four different airfoil sections was simulated applying the dynamic mesh. The results show that the time averaged thrust coefficient CTmean and propulsive efficiency η of the symmetric airfoil decrease with the increasing angle of attack, and the variation of CTmean is more obvious than that of CPmean. Both CTmean and η for NACA airfoils studied in this paper decrease with the increasing camber and the difference between the propulsion performances of different airfoils is not obvious, and the thrust generation and power of various NACA airfoils gradually increase during the downstroke and decrease during the upstroke. Under the same conditions, the airfoil with a further distance between the maximum camber location and the chord of the leading edge leads to higher propulsive efficiency.
A Post-Si CMP Cleaning Using BDD Film Electrochemical Oxidation
Authors: Zhu Ya Dong , Yang Xiao Ping , Gao Bao Hong
Published: March 2013

This paper presents a post-Si CMP cleaning using the boron-doped diamond (BDD) film electrode as anode in the electrochemical cleaning method. The BDD film electrode has wide potential window and high oxygen evolution potential, so it is able to electrochemically generate super-advanced oxidation free radicals, such as hydroxyl radicals, oxygen free radicals and so on. And the sub-product of the radicals are ozone and hydrogen peroxide. And the BDD film electrode electrochemically oxidation is an advanced oxidation technology. First using the surfactant to remove particles contaminants, then following this post-Si CMP cleaning, it can effectively remove organic as well as the adsorbed surfactant on the surface. The experiments of cleaning post-Si CMP wafer are introduced in this paper, and the results indicated that the effective cleaning process can meet the continuous development of microelectronic industry cleaning needs.
Study of the Parallel Hybrid Electric Vehicle Drive Train Fuzzy Logic Control Strategy
Authors: Zhang Yun , Yu Xiu Min , Bi Ming Xuan
Published: March 2013

Vehicle power train plays an important role to develop the energy efficient and reduce fuel consumption.In this paper,the drive train fuzzy controller structure and the fuzzy logic control strategies of parallel hybrid vehicles is presented. Simulation results illustrate the potential of the proposed controller and control strategy in terms of fuel economy and in keeping the deviations of SOC at a low level.
Influence of Vibration Inclination on Surface Quality and Tool Wear by Ultra-Precision Vibration-Assisted Cutting
Authors: Al-Zahrani Ahmed , Yang Jin Rong , Li Yong
Published: March 2013

Ultra-precision ultrasonic vibration-assisted cutting (UVC) with polycrystalline diamond (PCD) tool refers to the cutting with certain amplitude and high frequency tool vibration, which can definitely reduce the cutting forces and tool wear when compared with the conventional cutting. However, in the actual cutting process, the tool vibration direction is not strictly in accordance with the designed cutting direction based on the manufacturing dimension and installation accuracy error of the vibration device. It will result in an inclined cutting angled with the linear direction. The inclination angle leads to periodical grooves on the machined surface, therefore affecting the quality of machined surface. In addition, the inclined vibration cutting will also lead to an increase in cutting forces, thus exacerbating the PCD tool wear. This paper has analyzed the influence of inclined vibration on the roughness of machined surface. A finite element (FE) simulation model of inclined linear vibration cutting has also been set up to analyze the variations of cutting forces with different inclination angle, so as to explore the mechanism of tool wear. Moreover, ultra-precision ultrasonic vibration-assisted cutting (UVC) experiments with different inclination angle have been carried out. The machined surface and PCD tools have been investigated. Combining with the theoretical analysis, this work has concluded that inclined vibration will increase the roughness of machined surface as well as exacerbate the PCD tool wear. The effective techniques have been proposed to improve the surface quality and reduce the tool wear by reducing the inclination angle of vibration and with carbon atmosphere.
Design and Implementation of Metric Multi-Core Functional Simulator
Authors: Wang Yan , Zhang Bi Ying , Fu Zhong Chuan , Hu Wen
Published: March 2013

To integrate the programming model and the executing model, the procedure is introduced into the design of multi-core micro-architecture, and the method-centric (Metric) multi-core architecture is proposed. A functional simulator for Metric multi-core architecture is designed and implemented. The simulator is implemented with the object-oriented programming methodology, and is composed of three groups of components: functional simulator, ISA emulator and auxiliary components. The experimental results show that the implemented simulator is effective and correct.
Influence of Anvil Geometry on Stretching Process of Cylinder Forging with Materials Properties in Materials Engineering
Authors: Li Yong Hua , Zhang Jing , Liu Wei Yi
Published: March 2013

Stretching is a commonly used process to manufacture forgings with good quality. In this paper, the stretching process of cylinder forging with materials properties in materials engineering was investigated by finite element method. The metal flow law of cylinder stretching process was studied, based on the simulation and analysis of the effect of tool geometry like flat and V-shaped anvils on strain and stress distribution state in the forging. The reasonable tool geometry for stretching was V-shaped anvil.
Heavy Metal Distribution Inflected by Baishui Reclamation in Luoyuan Bay
Authors: Yu Dong , Lin Jian Guo , Guo Wei Jun
Published: March 2013

According to the features of Luoyuan Bay, such as the complex terrain, flexural coastline and the large area of tidal flat, well-known 3-D hydrodynamic moving-boundary numerical model FVCOM based on unstructured mesh is used to simulate this area. Based on this model, the tidal current field and tide-induced Eulerian residual current field of Luoyuan Bay can be obtained. The concentrations of 4 heavy metals were determined in 8 water bodies in Luoyuan Bay by an inductively coupled plasma mass spectroscopy (ICP-MS). The average concentrations of Cu, As, Cd and Pb are 3.92, 4.22, 0.201 and 5.27 μg/L, respectively. The results manifest that average levels of heavy metals in the vicinity of the reclamation project has increased significantly in recent years. According to the simulated hydrodynamic results analysis, the water power intensity weakens near the reclamation project with a residual current reducing water exchange capacity.
Discussion on the Sediment Internal Pollution and its Countermeasures of Nansi Lake
Authors: Wang Long Feng , Yang Li Yuan
Published: March 2013

Sediment is an important ecological part of the lake and has a high storage capacity. Based on the cognition of Nansi Lake, this article presents the main sediment internal pollution in Nansi Lake, including nutrient pollutants, heavy metal pollutants and persistent organic pollutants, then make some countermeasures to control pollution, which has certain guidance to the improvement of environmental contamination in Nansi Lake.
An Effect Analysis of Color Design in Guangzhou Subway System: From the Color Universal Design Perspective
Authors: Lin Jing Wei , Tang Jian
Published: March 2013

The Guangzhou Subway System adopts a planning scheme that guides passengers through a system of symbolic colors for its routes. However, the designers seem to have neglected color blind's difficulty in distinguishing some hues when selecting the routes' symbolic colors, which suggests that color universal design theories are not properly applied in their design work. This research aims at evaluating Guangzhou Subway’s symbolic color and guidance system from the color universal design perspective. We use the Vischeck[1] to simulate and analyze the practical situation. In accordance with the analysis, solutions are recommended.
Implicit 2D Numerical Simulation of Materials Submitted to High Strain Rates Including Fracture
Authors: Jeunechamps Pierre Paul , Ponthot Jean Philippe
Published: March 2013

In this paper, we present a general consistent numerical formulation able to take into account strain rate and thermal effects of the material behavior. A thermomechanical implicit approach for element erosion to model material failure is also presented. The numerical model will be illustrated by applications both from the metal forming and the impact domain. All these physical phenomena have been included in an implicit dynamic oriented object finite element code (implemented at LTAS-MN²L, University of Liège, Belgium) named Metafor [1].
Study on the Microstructure and Morphology of Sintering Process of SiC-TiB2 Composite
Authors: Jiang Liang , Bao Yi Wang , Chen Yu Hong , Wei Jie
Published: March 2013

This research employs pressureless sintering process to study the impact of different amount of titanium diboride on the performance of silicon carbide-titanium diboride composite. Results show that: no new phase was produced, and the whole process is a solid-phases sintering process. In this experiment, it has the smallest relative density and loss on ignition and porosity, and highest degree of densification of the silicon carbide-titanium diboride composite ceramics sintered body when the titanium diboride content is 50g, and the quality of SiC and TiB2 ratio is 1:1.
Research on Influence of Diffractometer Slits on XRD Pattern
Authors: Zhang Hua Yong , Xia Yong Mei , Liu Xiao Jian , Li Tian Duo
Published: March 2013

X-ray diffraction analysis is a convenient and important route to investigate crystalline materials. With powder materials, calcium carbonate as target, the effects of scatter slit, soller slit and receiving slit of Bruker D8 ADVANCE diffractometer on the diffraction pattern based on information, such as the background intensity, peak height, intensity and full width at half maximum, which provide the evidence for slits selection.
Study on the In Situ Growth of Carbon Nanotubes for the Reinforcement of Cf/SiC Composite Fabricated by CVI+PIP Process
Authors: Hu Jian Bao , Dong Shao Ming , Zhang Xiang Yu , Wang Zhen , Zhou Hai Jun , He Ping , Wu Bin
Published: March 2013

Cf/SiC composites were fabricated through in situ growth of carbon nanotubes (CNTs) on three-dimensional needle-punched carbon fabric via chemical vapor deposition and polymer impregnation and pyrolysis process. The mechanical and thermal properties of the composites were investigated. The flexural strength and fracture toughness were decreased due to the fiber volume fraction loss and much shorter pull-out length of fibers which was caused by the higher interfacial bonding strength between fiber and matrix after the growth of CNTs. Brittle fracture character of CNTs was observed due to the strong interfacial bonding strength between CNTs and matrix. The parallel thermal conductivity and perpendicular thermal conductivity were improved to 14.5% and 8.0% respectively.
Effects of Ho-Doping on Crystal Structure and Microstructure of La0.7Sr0.3MnO3 Ceramics
Authors: Sun Ben Zhe , Zhou Si Lang , Shen Tie
Published: March 2013

Crystal structure and microstructure of La0.7-xHoxSr0.3MnO3 (x=0.2,0.6) prepared by usual ceramic techniques and grinding procedure were investigated using X-ray diffraction (XRD) and transmission electron microscopy (TEM). When doping amount x equals to 0.2, incorporation of Ho atoms contributed to phase separation and coexistence of rhombohedral (La0.7Sr0.3MnO3) and hexagonal (HoMnO3) phases. La0.7Sr0.3MnO3 phase is of typical perovskite structure, whereas, HoMnO3 phase is non-perovskite structure. As x reaches 0.6, the volume fraction of HoMnO3 phase was significantly increasing. Meanwhile, an orthorhombic lattice with perovskite structure and space group Pnma can be observed. It prevented from partial substitution of La 3+ or Sr2+ by Ho3+ and the distortion of Mn-O octahedra.
On γ-γ’ Eutectic Quantitative Evaluation in the as-Cast CMSX-4 Nickel-Based Superalloy
Authors: Szczotok Agnieszka
Published: March 2013

The aim of the work is estimation of usefulness of several selected etchants and image acquisition methods for revealing of microstructure of CMSX-4 nickel–based superalloy from computer-aided quantitative metallography’s point of view. The analysis was carried out on images registered using light and scanning electron microscopes. The images of the microstructure have been analyzed in γ γ’ eutectic’s investigations context, especially to estimate the eutectic quantitatively. The work contains description of experimental method for quantitative evaluation of γ γ’ eutectic present in as-cast state of the superalloy. A quantitative evaluation of γ γ’ eutectic islands in CMSX 4 superalloy is indispensable for a proper evaluation of γ’ phase precipitates. It is mainly related to coarse cellular γ’ phase precipitates present in γ γ’ eutectic islands.
Glucocorticoids Induce Effector T Cell Depolarization via ERM Proteins, Thereby Impeding Migration and APC Conjugation
Authors: Müller Nora , Fischer Henrike J. , Tischner Denise , van den Brandt Jens , Reichardt Holger M.
Published: March 2013

Glucocorticoids (GCs) repress lymphocyte function by controlling gene expression. In this study, we investigated Ag-specific effector T cells and provide evidence that GCs also modulate these cells’ cytoskeletal architecture by nongenomic mechanisms. Following GC treatment, effector T cells rapidly lose their polarized morphology, which impedes both their migratory capacity and their interaction with APCs. The cytoskeleton rearrangements are preceded by an activation of ezrin–radixin–moesin proteins, which transiently increases the cellular rigidity but seems to occur independently of altered tyrosine phosphorylation. Phospholipase C activity is critically involved in mediating these nongenomic effects, because its inhibition prevents both T cell depolarization and ezrin–radixin–moesin phosphorylation after GC exposure. GC administration in vivo induced similar morphological changes in effector T cells as observed in vitro, suggesting that the above process plays a role in modulating inflammatory diseases. Taken together, our findings identify a novel mechanism through which GCs rapidly repress T cell function independently of gene transcription.
Discovery of T Cell Epitopes Implementing HLA-Peptidomics into a Reverse Immunology Approach
Authors: Hombrink Pleun , Hassan Chopie , Kester Michel G. D. , de Ru Arnoud H. , van Bergen Cornelis A. M. , Nijveen Harm , Drijfhout Jan W. , Falkenburg J. H. Frederik , Heemskerk Mirjam H. M. , van Veelen Peter A.
Published: March 2013

T cell recognition of minor histocompatibility Ags (MiHA) plays an important role in the graft-versus-tumor effect of allogeneic stem cell transplantation. Selective infusion of T cells reactive for hematopoiesis-restricted MiHA presented in the context of HLA class I or II molecules may help to separate the graft-versus-tumor effects from graft-versus-host disease effects after allogeneic stem cell transplantation. Over the years, increasing numbers of MiHA have been identified by forward immunology approaches, and the relevance of these MiHA has been illustrated by correlation with clinical outcome. As the tissue distribution of MiHA affects the clinical outcome of T cell responses against these Ags, it would be beneficial to identify additional predefined MiHA that are exclusively expressed on hematopoietic cells. Therefore, several reverse immunology approaches have been explored for the prediction of MiHA. Thus far, these approaches frequently resulted in the identification of T cells directed against epitopes that are not naturally processed and presented. In this study we established a method for the identification of biologically relevant MiHA, implementing mass spectrometry–based HLA-peptidomics into a reverse immunology approach. For this purpose, HLA class I binding peptides were eluted from transformed B cells, analyzed by mass spectrometry, and matched with a database dedicated to identifying polymorphic peptides. This process resulted in a set of 40 MiHA candidates that were evaluated in multiple selection steps. The identification of LB-NISCH-1A demonstrated the technical feasibility of our approach. On the basis of these results, we present an approach that can be of value for the efficient identification of MiHA or other T cell epitopes.
Candida albicans Primes TLR Cytokine Responses through a Dectin-1/Raf-1–Mediated Pathway
Authors: Ifrim Daniela C. , Joosten Leo A. B. , Kullberg Bart-Jan , Jacobs Liesbeth , Jansen Trees , Williams David L. , Gow Neil A. R. , van der Meer Jos W. M. , Netea Mihai G. , Quintin Jessica
Published: March 2013

The immune system is essential to maintain homeostasis with resident microbial populations, ensuring that the symbiotic host–microbial relationship is maintained. In parallel, commensal microbes significantly shape mammalian immunity at the host mucosal surface, as well as systemically. Candida albicans is an opportunistic pathogen that lives as a commensal on skin and mucosa of healthy individuals. Little is known about its capacity to modulate responses toward other microorganisms, such as colonizing bacteria (e.g., intestinal microorganisms). The aim of this study was to assess the cytokine production of PBMCs induced by commensal bacteria when these cells were primed by C. albicans. We show that C. albicans and β-1,3-glucan induce priming of human primary mononuclear cells and this leads to enhanced cytokine production upon in vitro stimulation with TLR ligands and bacterial commensals. This priming requires the β-1,3-glucan receptor dectin-1 and the noncanonical Raf-1 pathway. In addition, although purified mannans cannot solely mediate the priming, the presence of mannosyl residues in the cell wall of C. albicans is nevertheless required. In conclusion, C. albicans is able to modify cytokine responses to TLR ligands and colonizing bacteria, which is likely to impact the inflammatory reaction during mucosal diseases.
The Role of IL-1β in the Early Tumor Cell–Induced Angiogenic Response
Authors: Carmi Yaron , Dotan Shahar , Rider Peleg , Kaplanov Irena , White Malka R. , Baron Rona , Abutbul Shai , Huszar Monica , Dinarello Charles A. , Apte Ron N. , Voronov Elena
Published: March 2013

In this study, we assessed the involvement of IL-1β in early angiogenic responses induced by malignant cells using Matrigel plugs supplemented with B16 melanoma cells. We found that during the angiogenic response, IL-1β and vascular endothelial growth factor (VEGF) interact in a newly described autoinduction circuit, in which each of these cytokines induces the other. The IL-1β and VEGF circuit acts through interactions between bone marrow–derived VEGF receptor 1+/IL-1R1+ immature myeloid cells and tissue endothelial cells. Myeloid cells produce IL-1β and additional proinflammatory cytokines, which subsequently activate endothelial cells to produce VEGF and other proangiogenic factors and provide the inflammatory microenvironment for angiogenesis and tumor progression. These mechanisms were also observed in a nontumor early angiogenic response elicited in Matrigel plugs by either rIL-1β or recombinant VEGF. We have shown that IL-1β inhibition stably reduces tumor growth by limiting inflammation and inducing the maturation of immature myeloid cells into M1 macrophages. In sharp contrast, only transient inhibition of tumor growth was observed after VEGF neutralization, followed by tumor recurrence mediated by rebound angiogenesis. This occurs via the reprogramming of VEGF receptor 1+/IL-1R1+ cells to express hypoxia inducible factor-1α, VEGF, and other angiogenic factors, thereby directly supporting proliferation of endothelial cells and blood vessel formation in a paracrine manner. We suggest using IL-1β inhibition as an effective antitumor therapy and are currently optimizing the conditions for its application in the clinic.
Potential Contribution of a Novel Tax Epitope–Specific CD4+ T Cells to Graft-versus-Tax Effect in Adult T Cell Leukemia Patients after Allogeneic Hematopoietic Stem Cell Transplantation
Authors: Tamai Yotaro , Hasegawa Atsuhiko , Takamori Ayako , Sasada Amane , Tanosaki Ryuji , Choi Ilseung , Utsunomiya Atae , Maeda Yasuhiro , Yamano Yoshihisa , Eto Tetsuya , Koh Ki-Ryang , Nakamae Hirohisa , Suehiro Youko , Kato Koji , Takemoto Shigeki , Okamura Jun , Uike Naokuni , Kannagi Mari
Published: March 2013

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an effective treatment for adult T cell leukemia/lymphoma (ATL) caused by human T cell leukemia virus type 1 (HTLV-1). We previously reported that Tax-specific CD8+ cytotoxic T lymphocyte (CTL) contributed to graft-versus-ATL effects in ATL patients after allo-HSCT. However, the role of HTLV-1–specific CD4+ T cells in the effects remains unclear. In this study, we showed that Tax-specific CD4+ as well as CD8+ T cell responses were induced in some ATL patients following allo-HSCT. To further analyze HTLV-1–specific CD4+ T cell responses, we identified a novel HLA-DRB1*0101–restricted epitope, Tax155–167, recognized by HTLV-1–specific CD4+ Th1-like cells, a major population of HTLV-1–specific CD4+ T cell line, which was established from an ATL patient at 180 d after allo-HSCT from an unrelated seronegative donor by in vitro stimulation with HTLV-1–infected cells from the same patient. Costimulation of PBMCs with both the identified epitope (Tax155–167) and known CTL epitope peptides markedly enhanced the expansion of Tax-specific CD8+ T cells in PBMCs compared with stimulation with CTL epitope peptide alone in all three HLA-DRB1*0101+ patients post–allo-HSCT tested. In addition, direct detection using newly generated HLA-DRB1*0101/Tax155–167 tetramers revealed that Tax155–167-specific CD4+ T cells were present in all HTLV-1–infected individuals tested, regardless of HSCT. These results suggest that Tax155–167 may be the dominant epitope recognized by HTLV-1–specific CD4+ T cells in HLA-DRB1*0101+–infected individuals and that Tax-specific CD4+ T cells may augment the graft-versus-Tax effects via efficient induction of Tax-specific CD8+ T cell responses.
Clonally Diverse T Cell Homeostasis Is Maintained by a Common Program of Cell-Cycle Control
Authors: Hogan Thea , Shuvaev Andrey , Commenges Daniel , Yates Andrew , Callard Robin , Thiebaut Rodolphe , Seddon Benedict
Published: March 2013

Lymphopenia induces T cells to undergo cell divisions as part of a homeostatic response mechanism. The clonal response to lymphopenia is extremely diverse, and it is unknown whether this heterogeneity represents distinct mechanisms of cell-cycle control or whether a common mechanism can account for the diversity. We addressed this question by combining in vivo and mathematical modeling of lymphopenia-induced proliferation (LIP) of two distinct T cell clonotypes. OT-I T cells undergo rapid LIP accompanied by differentiation that superficially resembles Ag-induced proliferation, whereas F5 T cells divide slowly and remain naive. Both F5 and OT-I LIP responses were most accurately described by a single stochastic division model where the rate of cell division was exponentially decreased with increasing cell numbers. The model successfully identified key biological parameters of the response and accurately predicted the homeostatic set point of each clone. Significantly, the model was successful in predicting interclonal competition between OT-I and F5 T cells, consistent with competition for the same resource(s) required for homeostatic proliferation. Our results show that diverse and heterogenous clonal T cell responses can be accounted for by a single common model of homeostasis.
Adaptive Immunity Does Not Strongly Suppress Spontaneous Tumors in a Sleeping Beauty Model of Cancer
Authors: Rogers Laura M. , Olivier Alicia K. , Meyerholz David K. , Dupuy Adam J.
Published: March 2013

The tumor immunosurveillance hypothesis describes a process by which the immune system recognizes and suppresses the growth of transformed cancer cells. A variety of epidemiological and experimental evidence supports this hypothesis. Nevertheless, there are a number of conflicting reports regarding the degree of immune protection conferred, the immune cell types responsible for protection, and the potential contributions of immunosuppressive therapies to tumor induction. The purpose of this study was to determine whether the adaptive immune system actively suppresses tumorigenesis in a Sleeping Beauty (SB) mouse model of cancer. SB transposon mutagenesis was performed in either a wild-type or immunocompromised (Rag2-null) background. Tumor latency and multiplicity were remarkably similar in both immune cohorts, suggesting that the adaptive immune system is not efficiently suppressing tumor formation in our model. Exceptions included skin tumors, which displayed increased multiplicity in wild-type animals, and leukemias, which developed with shorter latency in immune-deficient mice. Overall tumor distribution was also altered such that tumors affecting the gastrointestinal tract were more frequent and hemangiosarcomas were less frequent in immune-deficient mice compared with wild-type mice. Finally, genetic profiling of transposon-induced mutations identified significant differences in mutation prevalence for a number of genes, including Uba1. Taken together, these results indicate that B and T cells function to shape the genetic profile of tumors in various tumor types, despite being ineffective at clearing SB-induced tumors. To our knowledge, this study represents the first forward genetic screen designed to examine tumor immunosurveillance mechanisms.
Hecke algebras, finite general linear groups, and Heisenberg categorification
Authors: Licata Anthony , Savage Alistair
Published: March 2013

We define a category of planar diagrams whose Grothendieck group contains an integral version of the infinite rank Heisenberg algebra, thus yielding a categorification of this algebra. Our category, which is a

q

-deformation of one defined by Khovanov, acts naturally on the categories of modules for Hecke algebras of type

A

and finite general linear groups. In this way, we obtain a categorification of the bosonic Fock space. We also develop the theory of parabolic induction and restriction functors for finite groups and prove general results on biadjointness and cyclicity in this setting.

Erratum:
Due to a technical error, many lines in the diagrams were printed without indication of the corresponding direction (i.e. as simple lines instead of arrows). A corrected electronic version of the article can be downloaded .
Dubois torsion, $A$-polynomial and quantum invariants
Authors: Frohman Charles D. , Kania-Bartoszynska Joanna
Published: March 2013

It is shown that for knots with a sufficiently regular character variety the Dubois torsion detects the

A

-polynomial of the knot. A global formula for the integral of the Dubois torsion is given. The formula looks like the heat kernel regularization of the formula for the Witten–Reshetikhin–Turaev invariant of the double of the knot complement. The Dubois torsion is recognized as the pushforward of a measure on the character variety of the double of the knot complement coming from the square root of Reidemeister torsion. This is used to motivate a conjecture about quantum invariants detecting the

A

-polynomial.
Infrared composition of the Large Magellanic Cloud
Authors: Siudek M. , Pollo A. , Takeuchi T. T. , Ita Y. , Kato D. , Onaka T.
Published: March 2013

The evolution of galaxies and the history of star formation in the Universe are among the most important topics in today’s astrophysics. Especially, the role of small, irregular galaxies in the star-formation history of the Universe is not yet clear. Using the data from the AKARI IRC survey of the Large Magellanic Cloud at 3.2, 7, 11, 15, and 24 μm wavelengths, i.e., at the mid- and near-infrared, we have constructed a multiwavelength catalog containing data from a cross-correlation with a number of other databases at different wavelengths. We present the separation of different classes of stars in the LMC in color-color, and color-magnitude, diagrams, and analyze their contribution to the total LMC flux, related to point sources at different infrared wavelengths.
Prognosis and Predictors of Surgical Complications in Hepatocellular Carcinoma Patients With or Without Cirrhosis after Hepatectomy
Authors: Mizuguchi Toru , Kawamoto Masaki , Meguro Makoto , Nakamura Yukio , Ota Shigenori , Hui Thomas T. , Hirata Koichi
Published: March 2013

Background

Although poor liver function is associated with a high morbidity rate and poor prognosis in hepatocellular carcinoma (HCC) patients, the exact effects of liver pathology on the surgical outcomes of HCC patients are poorly understood. The purpose of this study was to assess how the liver pathology of HCC patients affects their prognosis and complications rate after liver resection.

Methods

Between January 2006 and November 2010, 149 consecutive hepatocellular carcinoma patients, including 79 noncirrhosis patients and 70 cirrhosis patients, were enrolled in this study.

Results

Among the noncirrhotic patients, operative time, fresh frozen plasma (FFP) transfusion requirement, tumor size, and serum retinol binding protein (RBP) levels were significantly higher in the complications group than in the complications‐free groups. On the other hand, in the cirrhotic patients the prothrombin time (PT) and indocyanine green retention value at 15 min (ICGR15) of the complications group were significantly lower and higher, respectively, than those of the complications‐free group. In the noncirrhotic patients, recurrence‐free survival and overall survival did not differ between the complications and complications‐free groups. On the other hand, in the cirrhotic patients, the recurrence‐free survival and overall survival of the complications‐free group were significantly longer than those of the complications group.

Conclusions

In the noncirrhotic patients, surgical complications had no prognostic effect, whereas they had a significant survival impact in the cirrhotic patients. The surgical strategy for HCC should be based on the patient’s pathological background.
Polysaccharide hydrolysis with engineeredEscherichia colifor the production of biocommodities
Authors: Muñoz-Gutiérrez Iván , Martinez Alfredo
Published: March 2013

Escherichia coli can ferment a broad range of sugars, including pentoses, hexoses, uronic acids, and polyols. These features make E. coli a suitable microorganism for the development of biocatalysts to be used in the production of biocommodities and biofuels by metabolic engineering. E. coli cannot directly ferment polysaccharides because it does not produce and secrete the necessary saccharolytic enzymes; however, there are many genetic tools that can be used to confer this ability on this prokaryote. The construction of saccharolytic E. coli strains will reduce costs and simplify the production process because the saccharification and fermentation can be conducted in a single reactor with a reduced concentration or absence of additional external saccharolytic enzymes. Recent advances in metabolic engineering, surface display, and excretion of hydrolytic enzymes provide a framework for developing E. coli strains for the so-called consolidated bioprocessing. This review presents the different strategies toward the development of E. coli strains that have the ability to display and secrete saccharolytic enzymes to hydrolyze different sugar-polymeric substrates and reduce the loading of saccharolytic enzymes.
New strategy to improve efficiency for gene replacement in Klebsiella pneumoniae
Authors: Wei Dong , Sun Junsong , Shi Jiping , Liu Pengfu , Hao Jian
Published: March 2013

We previously reported the method for introducing gene replacement into Klebsiella pneumoniae through Red-assisted homologous recombination; and it demonstrated that a higher transformation efficiency required long flanking arms at both ends of the linear DNA. The assembly job of the linear DNA is usually time-consuming and laborious. We report here an innovative method for DNA exchange in K. pneumoniae based on PCR-mediated Red recombination. The novel procedure enables rapid gene replacement in K. pneumoniae without prior cloning of the gene of interest; the key modification is to perform PCR reaction to generate linear DNA with extra non-homologous fragments on both ends as mercenary sequences which come from a TA-cloning plasmid. We give a demonstration by deleting the gene dhak1 in K. pneumoniae with high efficiency of about 20 CFU/μg DNA using the new technique.
A Nondegenerate Penalized Likelihood Estimator for Variance Parameters in Multilevel Models
Authors: Chung Yeojin , Rabe-Hesketh Sophia , Dorie Vincent , Gelman Andrew , Liu Jingchen
Published: March 2013

Group-level variance estimates of zero often arise when fitting multilevel or hierarchical linear models, especially when the number of groups is small. For situations where zero variances are implausible a priori, we propose a maximum penalized likelihood approach to avoid such boundary estimates. This approach is equivalent to estimating variance parameters by their posterior mode, given a weakly informative prior distribution. By choosing the penalty from the log-gamma family with shape parameter greater than 1, we ensure that the estimated variance will be positive. We suggest a default log-gamma(2,λ) penalty with λ→0, which ensures that the maximum penalized likelihood estimate is approximately one standard error from zero when the maximum likelihood estimate is zero, thus remaining consistent with the data while being nondegenerate. We also show that the maximum penalized likelihood estimator with this default penalty is a good approximation to the posterior median obtained under a noninformative prior.

Our default method provides better estimates of model parameters and standard errors than the maximum likelihood or the restricted maximum likelihood estimators. The log-gamma family can also be used to convey substantive prior information. In either case—pure penalization or prior information—our recommended procedure gives nondegenerate estimates and in the limit coincides with maximum likelihood as the number of groups increases.
Hearing relative clauses boosts relative clause usage (and referential clarity) in young Turkish language learners
Authors: SARILAR AYŞE , MATTHEWS DANIELLE , KÜNTAY AYLIN C.
Published: March 2013

On account of both their functional and their morphosyntactic characteristics, relative clauses are often viewed as indicators of complexity in child language. Morphosyntactic properties of Turkish make use of particularly arduous relative clauses in spontaneous early discourse. A matching sticker selection task was used to determine whether Turkish-learning 3- and 4-year-olds can be trained to use subject relative clauses and uniquely identifying constructions. Upon their selection of the accurate sticker, the children were exposed to relative clause constructions (relative clause condition), sentences with demonstrative pronouns (demonstrative noun phrase condition), or a general approval (positive feedback condition). The number of relative clauses increased from pretest to posttest only in the relative clause condition; the rate of using adequately discriminating forms increased in all the three conditions, albeit with a steeper increase in the relative clause condition. The results are discussed in the framework of both structural and pragmatic priming.
Uniform Total Internal Reflection Fluorescence Illumination Enables Live Cell Fluorescence Resonance Energy Transfer Microscopy
Authors: Lin Jia , Hoppe Adam D.
Published: March 2013

Fluorescence resonance energy transfer (FRET) microscopy is a powerful technique to quantify dynamic protein-protein interactions in live cells. Total internal reflection fluorescence (TIRF) microscopy can selectively excite molecules within about 150 nm of the glass-cell interface. Recently, these two approaches were combined to enable high-resolution FRET imaging on the adherent surface of living cells. Here, we show that interference fringing of the coherent laser excitation used in TIRF creates lateral heterogeneities that impair quantitative TIRF-FRET measurements. We overcome this limitation by using a two-dimensional scan head to rotate laser beams for donor and acceptor excitation around the back focal plane of a high numerical aperture objective. By setting different radii for the circles traced out by each laser in the back focal plane, the penetration depth was corrected for different wavelengths. These modifications quell spatial variations in illumination and permit calibration for quantitative TIRF-FRET microscopy. The capability of TIRF-FRET was demonstrated by imaging assembled cyan and yellow fluorescent protein–tagged HIV-Gag molecules in single virions on the surfaces of living cells. These interactions are shown to be distinct from crowding of HIV-Gag in lipid rafts.
NanoGrande: Electron Microscopy Education and Outreach Through a Collaboration of Scientists and Artists
Authors: Catravas P. , Bubriski K. , Frey M. D. , Hagerman M. E. , Cohen B. , McGee J. J. , Bowser S. S.
Published: March 2013

NanoGrande is the culmination of an art-science effort that brought undergraduate students and faculty from science, engineering, and the visual arts together with professional microscopists of the Capital District Microscopy and Microanalysis Society for electron microscopy education and outreach. Students from two independent undergraduate courses, an advanced photography course and a microscopy laboratory course, collaborated on the project. The participants represented a wide range of majors, including chemistry, biology, electrical engineering, computer engineering, mechanical engineering, bioengineering, psychology, neuroscience, sociology/social sciences, history, and the visual arts. Emphasis was placed on both the scientific and the artistic aspects of the imaging process. The creation of electron microscopy images that were at the same time scientifically meaningful and visually compelling depended critically on communication of insights and ideas between paired students. The collaboration generated an art-science exhibition, NanoGrande, that has been presented to over four-thousand K through 12 students.
Can nonadditive dispersion forces explain chain formation of nanoparticles?
Authors: Kwaadgras Bas W. , Verdult Maarten W. J. , Dijkstra Marjolein , Roij René van
Published: March 2013

We study to what extent dielectric nanoparticles prefer to self-assemble into linear chains or into more compact structures. To calculate the Van der Waals (VdW) attraction between the clusters we use the Coupled Dipole Method (CDM), which treats each atom in the nanoparticle as an inducible oscillating point dipole. The VdW attraction then results from the full many-body interactions between the dipoles. For non-capped nanoparticles, we calculate in which configuration the VdW attraction is maximal. We find that in virtually all cases we studied, many-body effects only result in local potential minima at the linear configuration, as opposed to global ones, and that these metastable minima are in most cases rather shallow compared to the thermal energy. In this work, we also compare the CDM results with those from Hamaker-de Boer and Axilrod-Teller theory to investigate the influence of the many-body effects and the accuracy of these two approximate methods.
A numerical study on distributions during cryoprotectant loading caused by laminar flow in a microchannel
Authors: Scherr T. , Pursley S. , Monroe W. T. , Nandakumar K.
Published: March 2013

In this work, we conduct a computational study on the loading of cryoprotective agents into cells in preparation for cryopreservation. The advantages of microfluidics in cryopreserving cells include control of fluid flow parameters for reliable cryoprotectant loading and reproducible streamlined processing of samples. A 0.25 m long, three inlet T-junction microchannel serves as an idealized environment for this process. The flow field and concentration distribution are determined from a computational fluid dynamics study and cells are tracked as inert particles in a Lagrangian frame. These particles are not confined to streamlines but can migrate laterally due to the Segre-Sildeberg effect for particles in a shear flow. During this tracking, the local concentration field surrounding the cell is monitored. This data are used as input into the Kedem-Katchalsky equations to numerically study passive solute transport across the cell membrane. As a result of the laminar flow, each cell has a unique pathline in the flow field resulting in different residence times and a unique external concentration field along its path. However, in most previous studies, the effect of a spatially varying concentration field on the transport across the cell membrane is ignored. The dynamics of this process are investigated for a population of cells released from the inlet. Using dimensional analysis, we find a governing parameter α, which is the ratio of the time scale for membrane transport to the average residence time in the channel. For α<=0.224, cryoprotectant loading is completed to within 5% of the target concentration for all of the cells. However, for α>0.224, we find the population of cells does not achieve complete loading and there is a distribution of intracellular cryoprotective agent concentration amongst the population. Further increasing α beyond a value of 2 leads to negligible cryoprotectant loading. These simulations on populations of cells may lead to improved microfluidic cryopreservation protocols where more consistent cryoprotective agent loading and freezing can be achieved, thus increasing cell survival.
C58 on Au(111): A scanning tunneling microscopy study
Authors: Bajales Noelia , Schmaus Stefan , Miyamashi Toshio , Wulfhekel Wulf , Wilhelm Jan , Walz Michael , Stendel Melanie , Bagrets Alexej , Evers Ferdinand , Ulas Seyithan , Kern Bastian , Böttcher Artur , Kappes Manfred M.
Published: March 2013

C58 fullerenes were adsorbed onto room temperature Au(111) surface by low-energy (∼6 eV) cluster ion beam deposition under ultrahigh vacuum conditions. The topographic and electronic properties of the deposits were monitored by means of scanning tunnelling microscopy (STM at 4.2 K). Topographic images reveal that at low coverages fullerene cages are pinned by point dislocation defects on the herringbone reconstructed gold terraces (as well as by step edges). At intermediate coverages, pinned monomers act as nucleation centres for the formation of oligomeric C58 chains and 2D islands. At the largest coverages studied, the surface becomes covered by 3D interlinked C58 cages. STM topographic images of pinned single adsorbates are essentially featureless. The corresponding local densities of states are consistent with strong cage-substrate interactions. Topographic images of [C58]n oligomers show a stripe-like intensity pattern oriented perpendicular to the axis connecting the cage centers. This striped pattern becomes even more pronounced in maps of the local density of states. As supported by density functional theory, DFT calculations, and also by analogous STM images previously obtained for C60 polymers [M. Nakaya, Y. Kuwahara, M. Aono, and T. Nakayama, J. Nanosci. Nanotechnol. 11, 2829 (2011)]10.1166/jnn.2011.3898, we conclude that these striped orbital patterns are a fingerprint of covalent intercage bonds. For thick C58 films we have derived a bandgap of 1.2 eV from scanning tunnelling spectroscopy data confirming that the outermost C58 layer behaves as a wide band semiconductor.
Correlation between magnetism and electronic structure of Zn1−xCoxO nanoparticles
Authors: Chess Jordan , Alanko Gordon , Tenne Dmitri A. , Hanna Charles B. , Punnoose Alex
Published: March 2013

Zn1−xCoxO nanoparticles (∼9 nm) were produced with x ranging from 0 to 0.2 using a forced hydrolysis method. X-ray diffraction measurements confirm the samples to be single phase, and reveal a systematic change in the lattice parameters upon cobalt doping. The unit cell volume V decreases up to x = 0.025 after which it stays roughly constant. The band gap energy (Eg), determined from the photoluminescence spectra gradually increases from x = 0 to 0.025 and then remains nearly constant for x > 0.025. Room temperature hysteresis loops, obtained using vibrating sample magnetometry, show a similar trend in the saturation magnetization (Ms). Undoped ZnO nanoparticles show a weak magnetic hysteresis; doping causes an increase in Ms up to x = 0.025 and then decreases to lower values for x > 0.025. The magnetic moment per Co ion μ decreases rapidly with x nearly following μ(x) ∝ 1/x, indicating that the moments from the Co ions have little impact on the observed magnetic properties. Electron paramagnetic resonance (EPR) data confirmed that the pure samples are free of any magnetic impurities, while all the doped samples show spectra corresponding to Co2+. The variation of the integrated EPR signal intensity with x also shows a maximum at x = 0.025. X-ray photoelectron spectroscopy confirm that the dopant is incorporated as high spin Co2+ ions for low x, but increasing fractions of the dopant ions change to Co3+ as x increases to 0.2. These results along with the strong correlation observed between the structural (V), electronic (Eg), and magnetic (Ms) properties of Zn1−xCoxO nanoparticles, and the rapid decrease in magnetic moment with increasing x, indicate that the observed changes in the magnetic properties are related to changes in the electronic structure of ZnO nanoparticles caused by dopant incorporation.
An active one-particle microrheometer: Incorporating magnetic tweezers to total internal reflection microscopy
Authors: Gong Xiangjun , Hua Li , Wu Chi , Ngai To
Published: March 2013

We present a novel microrheometer by incorporating magnetic tweezers in the total internal reflection microscopy (TIRM) that enables measuring of viscoelastic properties of materials near solid surface. An evanescent wave generated by a solid/liquid interface in the TIRM is used as the incident light source in the microrheometer. When a probe particle (of a few micrometers diameter) moves near the interface, it can interact with the evanescent field and reflect its position with respect to the interface by the scattered light intensity. The exponential distance dependence of the evanescent field, on the one hand, makes this technique extremely sensitive to small changes from z-fluctuations of the probe (with a resolution of several nanometers), and on the other, it does not require imaging of the probe with high lateral resolution. Another distinct advantage is the high sensitivity in determining the z position of the probe in the absence of any labeling. The incorporated magnetic tweezers enable us to effectively manipulate the distance of the embedded particle from the interface either by a constant or an oscillatory force. The force ramp is easy to implement through a coil current ramp. In this way, the local viscous and elastic properties of a given system under different confinements can therefore be measured by resolving the near-surface particle motion. To test the feasibility of applying this microrheology to soft materials, we measured the viscoelastic properties of sucrose and poly(ethylene glycol) solutions and compared the results to bulk rheometry. In addition, we applied this technique in monitoring the structure and properties of deformable microgel particles near the flat surface.