bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative Mycobacterium tuberculosis Spoligotype Distribution in Mexico
Authors: Vera-Cabrera Lucio , Ramos-Alvarez Jessica , Molina-Torres Carmen A. , Rivera-Morales Lydia Guadalupe , Rendón Adrian , Quiñones-Falconi Francisco , Ocampo-Candiani Jorge
Published: May 2014

In the present work, we studied the genetic diversity of
Mycobacterium tuberculosis
clinical isolates from patients according to their gender, age, and geographic location in Mexico. We did not observe any statistically significant differences in regard to age or gender. We found that spoligo international type 53 (SIT53) is more frequent in the northern states and that SIT119 predominates in central Mexico.
E1-Mediated Recruitment of a UAF1-USP Deubiquitinase Complex Facilitates Human Papillomavirus DNA Replication
Authors: Lehoux Michaël , Gagnon David , Archambault Jacques
Published: May 2014

The human papillomavirus (HPV) E1 helicase promotes viral DNA replication through its DNA unwinding activity and association with host factors. The E1 proteins from anogenital HPV types interact with the cellular WD repeat-containing factor UAF1 (formerly known as p80). Specific amino acid substitutions in E1 that impair this interaction inhibit maintenance of the viral episome in immortalized keratinocytes and reduce viral DNA replication by up to 70% in transient assays. In this study, we determined by affinity purification of UAF1 that it interacts with three deubiquitinating enzymes in C33A cervical carcinoma cells: USP1, a nuclear protein, and the two cytoplasmic enzymes USP12 and USP46. Coimmunoprecipitation experiments indicated that E1 assembles into a ternary complex with UAF1 and any one of these three USPs. Moreover, expression of E1 leads to a redistribution of USP12 and USP46 from the cytoplasm to the nucleus. Chromatin immunoprecipitation studies further revealed that E1 recruits these threes USPs to the viral origin in association with UAF1. The function of USP1, USP12, and USP46 in viral DNA replication was investigated by overproduction of catalytically inactive versions of these enzymes in transient assays. All three dominant negative USPs reduced HPV31 DNA replication by up to 60%, an effect that was specific, as it was not observed in assays performed with a truncated E1 lacking the UAF1-binding domain or with bovine papillomavirus 1 E1, which does not bind UAF1. These results highlight the importance of the USP1, USP12, and USP46 deubiquitinating enzymes in anogenital HPV DNA replication.

IMPORTANCE
Human papillomaviruses are small DNA tumor viruses that induce benign and malignant lesions of the skin and mucosa. HPV types that infect the anogenital tract are the etiological agents of cervical cancer, the majority of anal cancers, and a growing proportion of head-and-neck cancers. Replication of the HPV genome requires the viral protein E1, a DNA helicase that also interacts with host factors to promote viral DNA synthesis. We previously reported that the E1 helicase from anogenital HPV types associates with the WD40 repeat-containing protein UAF1. Here, we show that UAF1 bridges the interaction of E1 with three deubiquitinating enzymes, USP1, USP12, and USP46. We further show that these deubiquitinases are recruited by E1/UAF1 to the viral origin of DNA replication and that overexpression of catalytically inactive versions of these enzymes reduces viral DNA replication. These results highlight the need for an E1-associated deubiquitinase activity in anogenital HPV genome replication.
Human Immunodeficiency Virus Reverse Transcriptase Displays Dramatically Higher Fidelity under Physiological Magnesium Conditions
In Vitro
Authors: Achuthan Vasudevan , Keith Brian J. , Connolly Bernard A. , DeStefano Jeffrey J.
Published: May 2014

The fidelity of human immunodeficiency virus (HIV) reverse transcriptase (RT) has been a subject of intensive investigation. The mutation frequencies for the purified enzyme
in vitro
vary widely but are typically in the 10
−4
range (per nucleotide addition), making the enzyme severalfold less accurate than most polymerases, including other RTs. This has often been cited as a factor in HIV's accelerated generation of genetic diversity. However, cellular experiments suggest that HIV does not have significantly lower fidelity than other retroviruses and shows a mutation frequency in the 10
−5
range. In this report, we reconcile, at least in part, these discrepancies by showing that HIV RT fidelity
in vitro
is in the same range as cellular results from experiments conducted with physiological (for lymphocytes) concentrations of free Mg
2+
(∼0.25 mM) and is comparable to Moloney murine leukemia virus (MuLV) RT fidelity. The physiological conditions produced mutation rates that were 5 to 10 times lower than those obtained under typically employed
in vitro
conditions optimized for RT activity (5 to 10 mM Mg
2+
). These results were consistent in both commonly used
lacZ
α complementation and steady-state fidelity assays. Interestingly, although HIV RT showed severalfold-lower fidelity under high-Mg
2+
(6 mM) conditions, MuLV RT fidelity was insensitive to Mg
2+
. Overall, the results indicate that the fidelity of HIV replication in cells is compatible with findings of experiments carried out
in vitro
with purified HIV RT, providing more physiological conditions are used.

IMPORTANCE
Human immunodeficiency virus rapidly evolves through the generation and subsequent selection of mutants that can circumvent the immune response and escape drug therapy. This process is fueled, in part, by the presumably highly error-prone HIV polymerase reverse transcriptase (RT). Paradoxically, results of studies examining HIV replication in cells indicate an error frequency that is ∼10 times lower than the rate for RT in the test tube, which invokes the possibility of factors that make RT more accurate in cells. This study brings the cellular and test tube results in closer agreement by showing that HIV RT is not more error prone than other RTs and, when assayed under physiological magnesium conditions, has a much lower error rate than in typical assays conducted using conditions optimized for enzyme activity.
Accelerated, Spleen-Based Titration of Variant Creutzfeldt-Jakob Disease Infectivity in Transgenic Mice Expressing Human Prion Protein with Sensitivity Comparable to That of Survival Time Bioassay
Authors: Halliez Sophie , Reine Fabienne , Herzog Laetitia , Jaumain Emilie , Haïk Stéphane , Rezaei Human , Vilotte Jean-Luc , Laude Hubert , Béringue Vincent
Published: May 2014

The dietary exposure of the human population to the prions responsible for the bovine spongiform encephalopathy (BSE) epizooty has led to the emergence of variant Creutzfeldt-Jakob disease (vCJD). This fatal, untreatable neurodegenerative disorder is a growing public health concern because the prevalence of the infection seems much greater than the disease incidence and because secondary transmission of vCJD by blood transfusion or use of blood products has occurred. A current limitation in variant CJD risk assessment is the lack of quantitative information on the infectivity of contaminated tissues. To address this limitation, we tested the potential of a transgenic mouse line overexpressing human prion protein (PrP), which was previously reported to propagate vCJD prions. Endpoint titration of vCJD infectivity in different tissues was evaluated by two different methods: (i) the “classical” bioassay, based on the appearance of clinical symptoms and the detection of pathological prion protein in tissues of the inoculated mouse, and (ii) a shortened bioassay based on the detection of the protein in the mouse spleen at defined time points. The two methods proved equally sensitive in quantifying infectivity, even after very-low-dose inoculation of infected material, but the time schedule was shortened from ∼2.5 years to ∼1 year with the spleen bioassay. Compared to the “gold-standard” RIII model routinely used for endpoint titration of vCJD/BSE prions, either method improved the sensitivity by >2 orders of magnitude and allowed reevaluating the infectious titer of spleen from a vCJD individual at disease end stage to >1,000-fold-higher values.

IMPORTANCE
Here, we provide key reevaluation of the infectious titer of variant CJD brain and spleen tissues. The highly sensitive, accelerated spleen-based assay should thus constitute a key advance for variant CJD epidemiological and risk assessment purposes and should greatly facilitate future titration studies, including, for example, those aimed at validating decontamination procedures. The overlooked notion that the lymphoid tissue exhibits a higher capacity than the brain to replicate prions even after low-dose infection raises new questions about the molecular and/or cellular determinant(s) involved, a key issue regarding potent silent carriers of variant CJD in the lymphoid tissue.
Genus Beta Human Papillomavirus E6 Proteins Vary in Their Effects on the Transactivation of p53 Target Genes
Authors: White Elizabeth A. , Walther Johanna , Javanbakht Hassan , Howley Peter M.
Published: May 2014

The genus beta human papillomaviruses (beta HPVs) cause cutaneous lesions and are thought to be involved in the initiation of some nonmelanoma skin cancers (NMSCs), particularly in patients with the genetic disorder epidermodysplasia verruciformis (EV). We have previously reported that at least two of the genus beta HPV E6 proteins bind to and/or increase the steady-state levels of p53 in squamous epithelial cells. This is in contrast to a well-characterized ability of the E6 proteins of cancer-associated HPVs of genus alpha HPV, which inactivate p53 by targeting its ubiquitin-mediated proteolysis. In this study, we have investigated the ability of genus beta E6 proteins from eight different HPV types to block the transactivation of p53 target genes following DNA damage. We find that the E6 proteins from diverse beta HPV species and types vary in their capacity to block the induction of MDM2, p21, and proapoptotic genes after genotoxic stress. We conclude that some genus beta HPV E6 proteins inhibit at least some p53 target genes, although perhaps not by the same mechanism or to the same degree as the high-risk genus alpha HPV E6 proteins.

IMPORTANCEThis study addresses the ability of various human papillomavirus E6 proteins to block the activation of p53-responsive cellular genes following DNA damage in human keratinocytes, the normal host cell for HPVs. The E6 proteins encoded by the high-risk, cancer-associated HPV types of genus alpha HPV have a well-established activity to target p53 degradation and thereby inhibit the response to DNA damage. In this study, we have investigated the ability of genus beta HPV E6 proteins from eight different HPV types to block the ability of p53 to transactivate downstream genes following DNA damage. We find that some, but not all, genus beta HPV E6 proteins can block the transactivation of some p53 target genes. This differential response to DNA damage furthers the understanding of cutaneous HPV biology and may help to explain the potential connection between some beta HPVs and cancer.
Interaction of Kaposi's Sarcoma-Associated Herpesvirus ORF6 Protein with Single-Stranded DNA
Authors: Ozgur Sezgin , Griffith Jack
Published: May 2014

Kaposi's sarcoma-associated herpesvirus (KSHV) ORF6 is homologous to the herpes simplex virus 1 (HSV-1) ICP8 and Epstein-Barr virus (EBV) BALF2 proteins. Here, we describe its single-stranded DNA (ssDNA) binding properties. Based on previous findings with ICP8 and BALF2, a 60-amino-acid C-terminal deletion mutant of Orf6 was generated, and the protein was purified to explore the function of the C terminus in ssDNA binding. We showed that full-length ORF6 binds cooperatively to M13 ssDNA, disrupting its secondary structure and extending it to a length equivalent to that of duplex M13 DNA. The width of the ORF6-ssDNA filament is 9 nm, and a 7.3-nm repeat can be distinguished along the filament axis. Fluorescence polarization analysis revealed that the wild-type and C-terminal mutant ORF6 proteins bind equally well to short ssDNA substrates, with dissociation constant (

K
d

) values of 2.2 × 10
−7
M and 1.5 × 10
−7
M, respectively. These values were confirmed by electrophoretic mobility shift assay (EMSA) analysis, which also suggested that binding by the full-length protein may involve both monomers and small multimers. While no significant difference in affinities of binding between full-length ORF6 and the C-terminal deletion mutant were observed with the short DNAs, binding of the C-terminal mutant protein to M13 ssDNA showed a clear lack of cooperativity as seen by electron microscopy (EM). Incubation of a duplex DNA containing a long single-stranded tail with double-helical ORF6 protein filaments revealed that the ssDNA segment can be enveloped within the protein filament without disrupting the filament structure.

IMPORTANCE
This work describes the biochemical characterization of the single-stranded DNA binding protein of KSHV, ORF6, central to viral DNA replication in infected cells. A C-terminal deletion mutant protein was generated to aid in understanding the role of the C terminus in DNA binding. Here we analyze the binding of the wild-type and mutant proteins to short oligomeric and longer genomic ssDNA substrates. Although it is capable of interacting with the short substrates, the inability of mutant ORF6 to form oligomers in solution hindered it from fully covering the long genomic substrates. We previously showed that ORF6 forms long filaments in solution, and we showed here that these can absorb ssDNA without disruption of the filament structure. This work will provide an important basis for future studies by us and/or others.
Prolapsed giant sigmoid lipoma: a rare cause of adult ischaemic intussusception
Authors: Elliott Mark , Martin Jennifer , Mullan Fred
Published: May 2014

Intussusception is a rare cause of obstruction in adults and has a variable, non-specific presentation. Adult intussusception is usually associated with an underlying organic pathology, such as a benign or malignant tumour which acts as the lead point. Prolapse of the lead-point mass through the anal canal is an extremely rare presentation with very few reported cases in the literature. We describe a case of a 67-year-old man who presented with rectal prolapse of a large soft tissue mass. CT of the abdomen and barium enema revealed partial intussusception of an upper sigmoid lipomatous polyp. Examination under anaesthesia was performed and the prolapse reduced. A laparoscopic sigmoid colectomy was planned. The patient subsequently re-presented clinically unwell with a recurrent necrotic prolapsing mass. Laparotomy and sigmoid colectomy was performed and the patient recovered fully. The resected mass was a 7×4.5×4.0 cm necrotic sigmoid lipoma.
Deriving high-resolution spatiotemporal fishing effort of large-scale longline fishery from vessel monitoring system (VMS) data and validated by observer data
Authors: Chang Shui-Kai , Yuan Tzu-Lun
Published: May 2014

Estimating geo-referenced fishing effort is vital to develop advice for effective fisheries management. Many studies in recent decades have attempted to obtain complete, high-resolution effort data from vessel monitoring systems (VMSs). The main challenge in this regard is to develop a classification method for differentiating fishing activities (e.g., fishing days) from nonfishing activities in VMS data. This study developed a simple, novel classification criterion for a large-scale tuna longline (LTLL) fishery that has not been studied before. LTLL operations were first explored using observer data. Three approaches were designed for developing fishing-day classification criteria, using maximizing sum of sensitivity and specificity (SS) as the major performance measure and minimizing difference of SS as a reference. At least one VMS report with speed in the range of 2–5 kn (1 kn = 1.852 km·h–1) detected during the time-of-day period of 14:00–23:00 h was recommended as the criterion for defining a fishing day. Possible explanations for the differences between the estimated fishing days from VMS data and those reported on logbooks are discussed; most causes were related to specific features of the fishery.
Effectiveness monitoring for biodiversity: comparing 15 year old structural retention harvest areas to fires in boreal aspen
Authors: Huggard David J. , Grover Brigitte E. , Dzus Elston , Smith Matthew , Schieck Jim
Published: May 2014

Convergence of species composition in regenerating harvested areas and naturally disturbed forest is a critical component of forest management modeled after natural disturbances. We assessed convergence of birds, plants, and habitat structures in aspen (Populus tremuloides) stands harvested with structural retention by Alberta-Pacific Forest Industries Inc. (Al-Pac) 15 years ago with similar aged fire area, and examined a chronosequence of younger and older burned aspen stands from Alberta Biodiversity Monitoring Institute (ABMI) sites. Most habitat structures and many bird and plant species in the 15 year harvest areas were at levels similar to 20–40 year or >40 year fire areas. Snags, moss, and lichen cover, and a few groups of species were at lower levels in the harvest areas than comparable aged fire areas or older stands. Agglomerative clustering showed the plant community to be most similar to >40 year burned stands, with the bird community intermediate between >20 year and <20 year fire areas. A novel likelihood-based analysis of species estimated the 15 year harvest areas to have a community similar to forest sites with 36.8% human footprint, indicating substantial recovery of the harvest areas. Harvesting aspen stands with structural retention appears to be effective at allowing most biodiversity components to recover rapidly.
Production of quasimonochromatic X-ray microbeams using MeV-protons and a polycapillary X-ray half lens
Authors: Ploykrachang K. , Fukuda H. , Kondo K. , Oguri Y. , Hasegawa J.
Published: May 2014

In this paper, we have proposed monochromatic X-ray microbeams, produced by a proton-induced X-ray technique and a polycapillary X-ray half lens, as a tool for micro-X-ray fluorescence (XRF) analysis. A 30 μm thick planar Cu target was irradiated by a 2.5 MeV proton beam to produce Cu Kα X-rays (8.0 keV), and a polycapillary X-ray half lens was utilized to focus the X-rays emitted behind the Cu target. The focal spot size of the focused X-ray beam was 250 μm at full width at half maximum, which was verified using a knife-edge scanning method. The output focal distance and the depth of focus of the optics were measured to be 47 mm and 1 mm, respectively. A square grid pattern of Co thin films, formed on a thick Cu substrate by thermal evaporation, was used as a test sample for evaluation of the analytical performance of the micro-XRF setup. Two-dimensional mapping of the Co distribution on the Cu substrate was successful, and the spatial resolution was consistent with the beam spot size. For this Co layer, a minimum detection limit of 2.3 ng was achieved.
Real hypersurfaces in the complex quadric with Reeb parallel shape operator
Authors: Suh Young Jin
Published: May 2014

First, we introduce the notion of shape operator of Codazzi type for real hypersurfaces in the complex quadric Qm = SOm+2/SOmSO2. Next, we give a complete proof of non-existence of real hypersurfaces in Qm = SOm+2/SOmSO2 with shape operator of Codazzi type. Motivated by this result we have given a complete classification of real hypersurfaces in Qm = SOm+2/SOmSO2 with Reeb parallel shape operator.
Enhanced ferromagnetic properties of Cu doped two-dimensional GaN monolayer
Authors: Hussain Fayyaz , Cai Y. Q. , Khan M. Junaid Iqbal , Imran Muhammad , Rashid Muhammad , Ullah Hafeez , Ahmad Ejaz , Kousar Farhana , Ahmad S. A.
Published: May 2014

We demonstrate enhanced ferromagnetism in copper doped two-dimensional GaN monolayer ( GaN -ML). Our first principle calculation based on density functional theory predicted that nonmagnetic Cu -dopant with concentration of 6.25% to be ferromagnetic (FM) in 2D GaN layer which carries a magnetic moment of 2.0 μB per Cu atom and it is found to be long range magnetic coupling among the Cu -dopant. The Cu-dopant in 2D GaN -ML which can be explained in terms of p-d hybridization at Curie temperature and this dopant prefer the FM behavior in 2D GaN layer. Hence Cu doped 2D GaN layer shows strong magnetic properties so that it is a promising material in the field of spintronics.
Over-relaxed hit-and-run Monte Carlo for the uniform sampling of convex bodies with applications in metabolic network biophysics
Authors: De Concini G. , De Martino D.
Published: May 2014

The uniform sampling of convex regions in high dimension is an important computational issue, both from theoretical and applied point of view. The hit-and-run Monte Carlo algorithms are the most efficient methods known to perform it and one of their bottlenecks relies in the difficulty of escaping from tight corners in high dimension. Inspired by optimized Monte Carlo methods used in statistical mechanics, we define a new algorithm by over-relaxing the hit-and-run dynamics. We made numerical simulations on high-dimensional simplexes and hypercubes in order to test its performances, pointing out its improved ability to escape from angles and finally apply it to an inference problem in the steady state dynamics of metabolic networks.
Understanding the microscopic deformation mechanism and macroscopic mechanical behavior of nanocrystalline Ni by the long-term stress relaxation test
Authors: Shen Xixun , Zhang Congcong , Zeng Tao , Cheng Danhong , Lian Jianshe
Published: May 2014

The long-term stress relaxation tests with a relaxation time of about 7 h are performed on the bulk dense nanocrystalline Ni (with a mean grain size of 27 nm) pre-deformed at strain rate from 4.17 s-1- 4.17 × 10-6 s-1, where a phenomenon that the initial relaxation behavior of nc Ni depends on itself deformation history. That is, the nc Ni s pre-deformed at higher strain rate (not less than 4.17 × 10-3 s-1) exhibit a three-staged relaxation process from the initial near linear rapidly stress delayed (LRSD) stage and the subsequent lumber nonlinear stress delayed (LNSD) one and the final near linear slowly stress delayed (LSSD) one while only the later two stages are observed for the nc Ni s pre-deformed at low strain rate. The three-stage relaxation behavior is attributed to the transition from the initial dislocation-dominated plasticity to the mixture of dislocation motion and diffusion-based GB activity and finally to the entire diffusion-based GB activity including GB sliding or grain rotation in the rate-controlling deformation mechanism, which was illuminated by the attained three-staged strain rate sensitivity and activation volume and the exhaustion of mobile density of deformed nc Ni in the first two stages of relaxation. Such rate-controlling deformation mechanism well interpreted the macroscopic tensile mechanical behavior of nc Ni and simultaneously an optimizing strategy in improving the ductility of nc Ni is also mentioned.
Cartographic generalization of urban street networks based on gravitational field theory
Authors: Liu Gang , Li Yongshu , Li Zheng , Guo Jiawei
Published: May 2014

The automatic generalization of urban street networks is a constant and important aspect of geographical information science. Previous studies show that the dual graph for street–street relationships more accurately reflects the overall morphological properties and importance of streets than do other methods. In this study, we construct a dual graph to represent street–street relationship and propose an approach to generalize street networks based on gravitational field theory. We retain the global structural properties and topological connectivity of an original street network and borrow from gravitational field theory to define the gravitational force between nodes. The concept of multi-order neighbors is introduced and the gravitational force is taken as the measure of the importance contribution between nodes. The importance of a node is defined as the result of the interaction between a given node and its multi-order neighbors. Degree distribution is used to evaluate the level of maintaining the global structure and topological characteristics of a street network and to illustrate the efficiency of the suggested method. Experimental results indicate that the proposed approach can be used in generalizing street networks and retaining their density characteristics, connectivity and global structure.
DESIGN OF PWMSC CONTROLLER USING AUGMENTED LAGRANGIAN PARTICLE SWARM OPTIMIZATION ALGORITHM
Authors: SAFARI AMIN , SHAYANFAR HEIDAR ALI , SHAYEGHI HOSSEIN , AMELI AMIR
Published: May 2014

This paper presents a systematic process for designing a damping controller for pulse width modulated series compensator (PWMSC) to improve the angular stability of a multi-machine power system. The proposed controller is robust and tuned by satisfying the multiple H∞ performance criteria to stabilize the system at multiple operating conditions. The design problem has been converted into a constrained nonlinear optimization problem with the time domain-based objective function which is solved by an augmented Lagrangian particle swarm optimization (ALPSO) algorithm. The proposed control scheme has been implemented on two nonlinear test systems. The nonlinear simulation results clearly verify that the designed controller with proposed model improves the dynamic stability of the case studies, particularly when the operating loadings changes.
Seifert surfaces in open books, and pass moves on links
Authors: Hirose Susumu , Nakashima Yuusuke
Published: May 2014

The flat plumbing basket presentation of a link is introduced by Furihata, Hirasawa and Kobayashi. In this paper, we show that the pass-equivalence and an equivalence introduced by using the flat plumbing basket presentation are the same relation. Furthermore, we obtain an evaluation of the minimal number of bands used for the flat pluming basket presentation for a knot coming from the degree of the Alexander polynomial and the three genus of the knot.
Analytic evaluation of electromagnetic neutron–proton mass difference in Skyrme model
Authors: Kumar Rajesh
Published: May 2014

We calculate, here, the electromagnetic (em) neutron–proton mass difference analytically by using arctan ansatz in Skyrme model. The value so obtained is compared with those given in the literature. Our value agrees well with the widely accepted value in the literature.
On the similarity of particle and photon tunneling and multiple internal reflections in one-dimensional, two-dimensional and three-dimensional photon tunneling
Authors: Olkhovsky V. S.
Published: May 2014

The formal mathematical analogy between time-dependent quantum equation for the nonrelativistic particles and time-dependent equation for the propagation of electromagnetic waves had been studied in [A. I. Akhiezer and V. B. Berestezki, Quantum Electrodynamics (FM, Moscow, 1959) [in Russian] and S. Schweber, An Introduction to Relativistic Quantum Field Theory, Chap. 5.3 (Row, Peterson & Co, Ill, 1961)]. Here, we deal with the time-dependent Schrödinger equation for nonrelativistic particles and with time-dependent Helmholtz equation for electromagnetic waves. Then, using this similarity, the tunneling and multiple internal reflections in one-dimensional (1D), two-dimensional (2D) and three-dimensional (3D) particle and photon tunneling are studied. Finally, some conclusions and future perspectives for further investigations are presented.
OPTICAL PROPERTIES OF N-DOPED Cu2O THIN FILMS DEPOSITED BY RF-MAGNETRON SPUTTERING Cu2O TARGET
Authors: LAI GUOZHONG , WU YANGWEI , LIN LIMEI , QU YAN , LAI FACHUN
Published: May 2014

N -doped Cu 2 O films were deposited on quartz substrates by reactive magnetron sputtering a Cu 2 O target. The optical constants and thicknesses of the films with different nitrogen partial pressure (NPP) were retrieved from transmittance data by an optical model which combines the Forouhi–Bloomer model with modified Drude model. The results show that when NPP increases from 0.0 to 0.033 Pa, the optical gap decreases from 2.14 to 1.95 eV. Additionally, an optical absorption process in the infrared region below the optical band gap was observed for N -doped Cu 2 O films, which was not found in the pure Cu 2 O film. This is because an intermediate band (IB) in the band gap results from nitrogen doping. It is believed that N -doped Cu 2 O film with suitable NPP could be used to enhance the energy conversion efficiency for photovoltaic cells.
EFFECT OF MAGNETRON-SPUTTERED Al FILM ON LOW-TEMPERATURE PACK-ALUMINIZING COATING FOR OIL CASING STEEL N80
Authors: HUANG MIN , WANG YU , ZHANG MENG-XIAN , HUO YAN-QIU , GAO PENG-JIN
Published: May 2014

Low-temperature aluminizing coating was prepared onto the surface of oil casing steel N 80 with a magnetron-sputtered Al film to improve its corrosion resistance. Results show that magnetron-sputtered Al film is able to form gradient aluminide coating, composed of iron aluminide FeAl 3, Fe 2 Al 5 and Fe 3 Al with different contents of aluminum. Both the density and continuity of iron aluminide layer for oil casing steel N 80 with magnetron-sputtered Al film can be improved. Under the same corrosion condition, aluminized oil casing steel N 80 with a magnetron-sputtered Al film shows an outstanding corrosion resistance than those of original and aluminized ones without magnetron-sputtered Al film. The positive effect of Al film is considered as the concentration change of active Al atom for diffusion to form the aluminizing coating during the pack processing.
A class of braided monoidal categories via quasitriangular Hopf π-crossed coproduct algebras
Authors: Ma Tianshui , Liu Linlin , Li Haiying
Published: May 2014

Let π be a group and (H = {Hα}α∈π, μ, η) a Hopf π-algebra. First, we introduce the concept of quasitriangular Hopf π-algebra, and then prove that the left H-π-module category [Formula: see text], where (H, R) is a quasitriangular Hopf π-algebra, is a braided monoidal category. Second, we give the construction of Hopf π-crossed coproduct algebra [Formula: see text]. At last, the necessary and sufficient conditions for [Formula: see text] to be a quasitriangular Hopf π-algebra are derived, and in this case, [Formula: see text] is a braided monoidal category.
FABRICATION AND CHARACTERIZATION OF CALCIUM SILICATE SCAFFOLDS FOR TISSUE ENGINEERING
Authors: SHUAI CIJUN , MAO ZHONGZHENG , HAN ZIKAI , PENG SHUPING , LI ZHENG
Published: May 2014

Calcium silicate ( CaSiO 3) is a promising material due to its favorable biological properties. However, it was difficult to fabricate ceramic scaffolds with interconnected porous structure via conventional technology. In present study, CaSiO 3 scaffolds with totally interconnected pores were fabricated via selective laser sintering (SLS). The microstructure, mechanical and biological properties were examined. The results revealed that the powder gradually fused together with the reduction of voids and the elimination of particle boundary as the laser power increased in the range of 3–15 W with scanning electron microscope. Meanwhile the low-temperature phase (β- CaSiO 3) transformed into high-temperature phase (α- CaSiO 3) gradually, which decreased the mechanical properties of the obtained scaffolds. Besides, the compressive strength increased from 12.9 ± 2.34 MPa to 18.19 ± 1.24 MPa (the laser power is 12 w) and then decreased gradually with increasing laser power. In vitro biological properties of CaSiO 3 scaffolds sintered under optimal conditions indicated that the distribution of apatite mineralization became uniform as the amount of them increased after being immersed in simulated body fluids. In the meantime, the thin cytoplasmic extensions of MG-63 cells increased until formed a dense cell layer after 1–5 days of cell culture. The results suggested that the CaSiO 3 scaffold fabricated via SLS has potential application for bone tissue engineering.
DEVELOPMENT OF A SIX-DIMENSIONAL SENSOR FOR MINIMALLY INVASIVE ROBOTIC SURGERY
Authors: JIANG JUN , XIE LE , YU HAILONG , YU WENWEI , WU BO
Published: May 2014

In minimally invasive robotic surgery (MIRS), the force/torque which occurred between instruments and organs cannot be accessed by surgeon. This paper presents development of a six-dimensional sensor based on double-hole parallel crossing beam, which can be integrated into instruments of MIRS. The size of sensor is 9.8 mm (diameter) × 6 mm (height). The structure of the sensor can acquire the force signals directly. The decoupling mechanism of the sensor was analyzed. The result of the finite element analysis (FEA) showed that the maximum coupling error was 3.8%. The machining error of the sensor was also investigated, and it was feasible for numerical control (NC) machine tools to manufacture the components of the sensor. The experimental calibration and soft tissue experiment indicated that the developed sensor can measure the force/torque loaded on the instrument and can be used to obtain the force feedback in the application of teleoperation surgical robot.
Poisson structures on almost complex Lie algebroids
Authors: Popescu Paul
Published: May 2014

In this paper, we extend the almost complex Poisson structures from almost complex manifolds to almost complex Lie algebroids. Examples of such structures are also given and the almost complex Poisson morphisms of almost complex Lie algebroids are studied.
MARKET ORIENTATION, TECHNOLOGY ORIENTATION AND PRODUCT INNOVATION SUCCESS: INSIGHTS FROM CoPS
Authors: LIU JING , SU JINGQIN
Published: May 2014

This study explores how market orientation and technology orientation within fuzzy front end phases affect product innovation success in complex products and systems (CoPS) industry research and development (R&D) organisations. A sequential qualitative–quantitative mixed method was used with a single case study and a questionnaire survey. The case study results show mix effects of market orientation and technology orientation on CoPS innovation success within fuzzy front end phases. The empirical test results show that a market orientation facilitates both low-tech and high-tech CoPS innovation success and offer great benefits to mainstream customers. A technology orientation is beneficial to high-tech CoPS innovation success but has no impact on low-tech CoPS innovation success. The results have significant implications for CoPS firm strategies to facilitate product innovations and achieve competitive advantages.
STRATEGIC ENVIRONMENTAL ASSESSMENT IN THE MEXICAN ELECTRICITY SECTOR
Authors: MONTAÑEZ-CARTAXO LUIS E.
Published: May 2014

In Mexico, the Federal Commission of Electricity (CFE) is the public entity that is responsible for the annual preparation of the national programme of the electricity system development with a 15 year horizon (POISE in Spanish). Besides this national planning process, there are regional plans as well as others regarding the development of hydroelectric and geothermoelectric projects; these plans are essential inputs to prepare the POISE. Another key decision window is the site selection of the projects listed in the Program.

For a few years the Environmental Protection Division of CFE has been promoting the incorporation of SEA into the decision-making processes of the company. Two regional SEAs have been made so far. This paper presents the actions carried out to incorporate SEA into CFE since 2002, as well as the methodologies followed in each of the two cases, and primarily the lessons learned from these experiences.
SCENARIO MODELLING TO SUPPORT STRATEGIC ENVIRONMENTAL ASSESSMENT: APPLICATION TO SPATIAL PLANNING OF COASTAL WETLANDS IN LA ARAUCANÍA REGION, CHILE
Authors: ROZAS-VÁSQUEZ DANIEL , PEÑA-CORTÉS FERNANDO , GENELETTI DAVIDE , REBOLLEDO GONZALO
Published: May 2014

In order to support Strategic Environmental Assessment of spatial plans, different scenarios were developed for the future configuration of wetlands along the coast of La Araucanía Region for 2020. To assess each scenario, landscape metrics related to landscape dynamics and structure were used. The results indicate that in general terms the wetland cover diminished and fragmented under different scenarios, including one which was designed for the sustainability of natural areas. It is concluded that the techniques used were relatively easy to implement by means of GIS technologies, which facilitate spatially explicit modelling of future scenarios. Furthermore, landscape metrics were a key element for assessing the effects of each model. There are currently only few experiences on the use of spatially explicit scenarios in SEA and our research suggests that this may be a useful and valid tool for supporting spatial planning decisions.
Piedra Pajarilla: a candidacy as a global heritage stone resource for Martinamor granite
Authors: Pereira Dolores , Gimeno Ana , Del Barrio Santiago
Published: May 2014

Piedra Pajarilla is the local name under which the Martinamor granite was known when it was quarried during the 19th century. It is a leucogranite of Hercynian age, and here we present its formal nomination as a ‘Global Heritage Stone Resource’. Piedra Pajarilla fits the proposed designation because it has been used for centuries in the construction of major historical and famous buildings in Salamanca, leading the city to being included in the UNESCO World Heritage list in 1988. Piedra Pajarilla is no longer quarried, and this nomination will help to maintain the historical quarry for the restoration of the monuments if blocks need to be replaced.
Role of a looming-sensitive neuron in triggering the defense behavior of the praying mantisTenodera aridifolia
Authors: Sato Keiichiro , Yamawaki Yoshifumi
Published: May 2014

In responses to looming objects, the praying mantis shows a defense behavior, which consists of retracting forelegs under the prothorax. The role of a looming-sensitive neuron in triggering this behavior was investigated by simultaneously recording the activity and behavioral responses of the neuron. The mantis initiated the defense behavior earlier in response to larger and slower looming stimuli. The time remaining to collision at defense initiation was linearly correlated with the ratio of the half-size of an approaching object to its speed ( l/| v|), suggesting that the defense behavior occurred a fixed delay after the stimuli had reached a fixed angular threshold. Furthermore, the results suggested that high-frequency spikes of the looming-sensitive neuron were involved in triggering the defense behavior: the distribution of maximum firing rate for trials with defense was shifted to larger rates compared with trials without defense; the firing rate of the neuron exceeded 150 Hz ∼100 ms before the defense initiation regardless of stimulus parameters; when a looming stimulus ceased approach prematurely, high-frequency spikes were removed, and the occurrence of defense was reduced.
Changes in input strength and number are driven by distinct mechanisms at the retinogeniculate synapse
Authors: Lin David J. , Kang Erin , Chen Chinfei
Published: May 2014

Recent studies have demonstrated that vision influences the functional remodeling of the mouse retinogeniculate synapse, the connection between retinal ganglion cells and thalamic relay neurons in the dorsal lateral geniculate nucleus (LGN). Initially, each relay neuron receives a large number of weak retinal inputs. Over a 2- to 3-wk developmental window, the majority of these inputs are eliminated, and the remaining inputs are strengthened. This period of refinement is followed by a critical period when visual experience changes the strength and connectivity of the retinogeniculate synapse. Visual deprivation of mice by dark rearing from postnatal day (P)20 results in a dramatic weakening of synaptic strength and recruitment of additional inputs. In the present study we asked whether experience-dependent plasticity at the retinogeniculate synapse represents a homeostatic response to changing visual environment. We found that visual experience starting at P20 following visual deprivation from birth results in weakening of existing retinal inputs onto relay neurons without significant changes in input number, consistent with homeostatic synaptic scaling of retinal inputs. On the other hand, the recruitment of new inputs to the retinogeniculate synapse requires previous visual experience prior to the critical period. Taken together, these findings suggest that diverse forms of homeostatic plasticity drive experience-dependent remodeling at the retinogeniculate synapse.
Long-term deficits in motion detection thresholds and spike count variability after unilateral vestibular lesion
Authors: Yu Xiong-Jie , Thomassen Jakob S. , Dickman J. David , Newlands Shawn D. , Angelaki Dora E.
Published: May 2014

The vestibular system operates in a push-pull fashion using signals from both labyrinths and an intricate bilateral organization. Unilateral vestibular lesions cause well-characterized motor deficits that are partially compensated over time and whose neural correlates have been traced in the mean response modulation of vestibular nuclei cells. Here we compare both response gains and neural detection thresholds of vestibular nuclei and semicircular canal afferent neurons in intact vs. unilateral-lesioned macaques using three-dimensional rotation and translation stimuli. We found increased stimulus-driven spike count variability and detection thresholds in semicircular canal afferents, although mean responses were unchanged, after contralateral labyrinth lesion. Analysis of trial-by-trial spike count correlations of a limited number of simultaneously recorded pairs of canal afferents suggests increased noise correlations after lesion. In addition, we also found persistent, chronic deficits in rotation detection thresholds of vestibular nuclei neurons, which were larger in the ipsilesional than the contralesional brain stem. These deficits, which persisted several months after lesion, were due to lower rotational response gains, whereas spike count variability was similar in intact and lesioned animals. In contrast to persistent deficits in rotation threshold, translation detection thresholds were not different from those in intact animals. These findings suggest that, after compensation, a single labyrinth is sufficient to recover motion sensitivity and normal thresholds for the otolith, but not the semicircular canal, system.
Comparison of Anterior Corneal Curvature Measurements Using a Galilei Dual Scheimpflug Analyzer and Topcon Auto Kerato-Refractometer
Authors: Wang Xiaogang , Dong Jing , Wu Qiang
Published: May 2014

Purpose. To compare anterior corneal keratometry (K) measurements taken by a dual Scheimpflug analyzer and an auto kerato-refractometer.Methods. Sixty-four normal eyes underwent keratometric measurements with both devices. The repeatability of the auto kerato-refractometer measurements was assessed by calculating the coefficient of variation (COV). The interdevice agreement was evaluated using the Bland-Altman analysis, Pearson correlation coefficient, and paired two-tailedt-test.Results. The COV of the flatKand steepKmeasurements taken by the auto kerato-refractometer were 0.21% and 0.29%, respectively. There were no significant differences between the steepKand averageKmeasurements for the Topcon and Galilei devices (P= 0.475, andP= 0.137, resp.). The Galilei flatKvalues were lower than those of the Topcon (P= 0.002). Both of the instruments showed good agreement for all anterior corneal keratometric values. There was a significant linear correlation between the Galilei and Topcon devices for the flatK(r= 0.989,P< 0.0001), steepK(r= 0.987,P< 0.0001), and averageKvalues (r= 0.994,P< 0.0001).Conclusions. The anterior corneal flat keratometric values were not interchangeable between the Galilei and Topcon devices. However, the measurements of the two instruments showed significant linear correlation with each other.
On the Convergence of Biogeography‐Based Optimization for Binary Problems
Authors: Ma Haiping , Simon Dan , Fei Minrui
Published: May 2014

Biogeography‐based optimization (BBO) is an evolutionary algorithm inspired by biogeography, which is the study of the migration of species between habitats. A finite Markov chain model of BBO for binary problems was derived in earlier work, and some significant theoretical results were obtained. This paper analyzes the convergence properties of BBO on binary problems based on the previously derived BBO Markov chain model. Analysis reveals that BBO with only migration and mutation never converges to the global optimum. However, BBO with elitism, which maintains the best candidate in the population from one generation to the next, converges to the global optimum. In spite of previously published differences between genetic algorithms (GAs) and BBO, this paper shows that the convergence properties of BBO are similar to those of the canonical GA. In addition, the convergence rate estimate of BBO with elitism is obtained in this paper and is confirmed by simulations for some simple representative problems.
Chemical and Photometric Evolution Models for Disk, Irregular, and Low Mass Galaxies
Authors: Mollá Mercedes
Published: May 2014

We summarize the updated set of multiphase chemical evolution models performed with 44 theoretical radial mass initial distributions and 10 possible values of efficiencies to form molecular clouds and stars. We present the results about the infall rate histories, the formation of the disk, and the evolution of the radial distributions of diffuse and molecular gas surface density, stellar profile, star formation rate surface density, and elemental abundances of C, N, O, and Fe, finding that the radial gradients for these elements begin steeper and flatten with increasing time or decreasing redshift, although the outer disks always show a certain flattening for all times. With the resulting star formation and enrichment histories, we calculate the spectral energy distributions (SEDs) for each radial region by using the ones for single stellar populations resulting from the evolutive synthesis modelPOPSTAR. With these SEDs we may compute finally the broad band magnitudes and colors radial distributions in the Johnson and in the SLOAN/SDSS systems which are the main result of this work. We present the evolution of these brightness and color profiles with the redshift.
The Statistical Properties of Spin-One DKP Oscillator under an External Magnetic Field in Noncommutative Space
Authors: Hassanabadi S. , Ghominejad M.
Published: May 2014

The spin-one Duffin-Kemmer-Petiau oscillator in uniform magnetic field is studied in noncommutative formalism. The corresponding energy is obtained and thereby the corresponding thermal properties are obtained for both commutative and noncommutative cases.
Development of Discrete Adjoint Approach Based on the Lattice Boltzmann Method
Authors: Hekmat Mohamad Hamed , Mirzaei Masoud
Published: May 2014

The purpose of this research is to present a general procedure with low implementation cost to develop the discrete adjoint approach for solving optimization problems based on the LB method. Initially, the macroscopic and microscopic discrete adjoint equations and the cost function gradient vector are derived mathematically, in detail, using the discrete LB equation. Meanwhile, for an elementary case, the analytical evaluation of the macroscopic and microscopic adjoint variables and the cost function gradients are presented. The investigation of the derivation procedure shows that the simplicity of the Boltzmann equation, as an alternative for the Navier-Stokes (NS) equations, can facilitate the process of extracting the discrete adjoint equation. Therefore, the implementation of the discrete adjoint equation based on the LB method needs fewer attempts than that of the NS equations. Finally, this approach is validated for the sample test case, and the results gained from the macroscopic and microscopic discrete adjoint equations are compared in an inverse optimization problem. The results show that the convergence rate of the optimization algorithm using both equations is identical and the evaluated gradients have a very good agreement with each other.