bluuebunny/crossref_metadata_2025 huggingface dataset:
Colloidally Prepared Pt Nanoparticles for Heterogeneous Gas‐Phase Catalysis: Influence of Ligand Shell and Catalyst Loading on CO Oxidation Activity
Authors: Fenske Daniela , Sonström Patrick , Stöver Jörg , Wang Xiaodong , Borchert Holger , Parisi Jürgen , Kolny‐Olesiak Joanna , Bäumer Marcus , Al‐Shamery Katharina
Published: January 2010

In contrast to conventional methods, colloidally prepared heterogeneous supported metal catalysts are excellent systems to study the catalytic properties as a function of metal loading, monodispersity, particle shape, or the type of support without changing the other parameters, as will be demonstrated herein. Colloidal, ligand‐capped Pt nanoparticles deposited on oxide supports are investigated for CO adsorption and oxidation. Dodecylamine and different alkanethiols are used as ligands. IR spectroscopic experiments reveal that small molecules, such as CO, can pass through the ligand shell and can adsorb on the particle surface, even if the ligand shell is not removed by a special pretreatment. The ability to penetrate the shell was found to depend on the type of ligand used which renders ligand‐capped nanoparticles potentially interesting for reaction and selectivity control. In the case of CO oxidation, high activity is detected only at temperatures at which a partial loss of ligands has already occurred, resulting in a rather similar catalytic behavior independent on the type of ligand. However, there are no indications for poisoning of the catalysts by decomposition of the ligand shell. Simple purification procedures of the Pt nanoparticles are sufficient to avoid further poisoning effects. Depositing nanoparticles with the same size in different amounts on a support enabled a detailed study of the influence of metal loading on the activity. The activity per gram metal increases with the metal loading. Local autothermal heating is responsible for this effect, which is also detected for a reference system consisting of Pt nanoparticles prepared without a ligand shell.
Color constancy from invariant wavelength ratios. II. The nonspectral and global mechanisms
Authors: Pridmore Ralph W.
Published: January 2010

Given the spectral mechanism of color constancy (Part I of this series), the remaining nonspectral mechanism is formulated here in Part II by the constraint of correlation with known spectral illuminant–invariant functions, i.e., invariant wavelength ratios between constant hues, which plot straight parallel lines in the plane of wavelength and reciprocal illuminant color temperature (MK−1). The same is assumed to apply to nonspectral constant hues in the same plane and dominant wavelength scale extended to cover the nonspectrals (see accompanying article “Relative wavelength metric for the complete hue cycle …”). To simplify analysis, stimuli are optimal aperture colors; their monochromatic stimuli lie between 442 and 613 nm, common boundaries with optimal compound stimuli (nonspectrals). It is shown that the wavelengths and invariant ratios of spectral constant hues can be formulated exactly (±0.5%) from the ratios of an harmonic period, which shifts wavelength with MK−1. The formula implies this color‐constant hue cycle is isomorphic across illuminants and allows prediction of nonspectral constant hues. To identify these colorimetrically, their spectral complementary wavelengths are specified for various illuminants. This completes theglobal color constancy mechanism for the illuminant color temperature range 2800 to 25,000 K. © 2010 Wiley Periodicals, Inc. Col Res Appl, 2010
Step‐Mediated Anisotropic Adsorption and Condensation of tert‐Butylamine on Cu(111)
Authors: Chen Yumin , Deng Ke , Qiu Xiaohui , Wang Chen
Published: January 2010

Scanning tunneling microscopy (STM) combined with density functional theory (DFT) calculations were applied in studying the anisotropic adsorption and condensation of tert‐butylamine (t‐BA) molecules in the vicinity of the steps on the Cu(111) surface. The preferential adsorption at the upper step edges and uneven distribution of t‐BA in the vicinity of the steps illustrate the asymmetric electronic structure of the surface steps. Our observation demonstrates that the adsorption and diffusion of a polar molecule would be significantly mediated by steps on metal surfaces due to the molecule–step interaction and the intermolecular interactions.
The 19S proteasomal lid subunit POH1 enhances the transcriptional activation by Mitf in osteoclasts
Authors: Schwarz Toni , Sohn Chee , Kaiser Bria , Jensen Eric D. , Mansky Kim C.
Published: January 2010

The microphthalmia‐associated transcription factor (Mitf) regulates gene expression required for osteoclast differentiation. Genes regulated by Mitf have been previously identified. However, proteins that interact and regulate Mitf's activity in osteoclasts are not well known. Here, we report that POH1, a subunit of the 19S proteasome lid is a regulator of Mitf. We show that POH1 and Mitf interact in osteoclasts and that this interaction is dependent on RANKL signaling. Overexpression of POH1 increased Mitf's activation of 5XGal4‐TK and Acp5 promoters. The amino terminus of POH1 mediates the binding to Mitf and is sufficient to increase Mitf's transcriptional activity. Finally, we show that mutations in the JAMM motif of POH1 reduced Mitf activation of promoters. In summary, our results identify a novel mechanism of Mitf regulation in osteoclasts by POH1. J. Cell. Biochem. 109: 967–974, 2010. © 2010 Wiley‐Liss, Inc.
Thermal dissociation of tripropylamine as the first step in the growth of carbon nanotubes inside AlPO4‐5 channels
Authors: Liu J. W. , Liu Z. F.
Published: January 2010

Tripropylamine (TPA) is a template for the synthesis of porous AlPO4‐5, whose calcination in the absence of air leads to the formation of 4 Å single‐walled carbon nanotubes. The thermal dissociation of TPA is the first step in this remarkable process. We examined the dissociation mechanisms of TPA by first principles calculations, under three types of conditions. In the gas phase, the unimolecular dissociation was a complex process initiated by the breaking of either the NCα and the CαCβ bonds. Within a confined space inside neutral zeolitic channels, the diffusion of H radicals enhanced a cycle of reactions to produce dipropylamine and monopropylamine, in agreement with experimental observations. In the presence of an acidic site, the dissociation of TPA was catalyzed to produce ammonia and propylene molecules, which were identified as the precursors for the eventual formation of carbon nanotubes. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010
Bone marrow‐derived mesenchymal stem cells express the pericyte marker 3G5 in culture and show enhanced chondrogenesis in hypoxic conditions
Authors: Khan Wasim S. , Adesida Adetola B. , Tew Simon R. , Lowe Emma T. , Hardingham Timothy E.
Published: January 2010

Bone marrow‐derived mesenchymal stem cells are a potential source of cells for the repair of articular cartilage defects. Hypoxia has been shown to improve chondrogenesis in some cells. In this study, bone marrow‐derived stem cells were characterized and the effects of hypoxia on chondrogenesis investigated. Adherent bone marrow colony‐forming cells were characterized for stem cell surface epitopes, and then cultured as cell aggregates in chondrogenic medium under normoxic (20% oxygen) or hypoxic (5% oxygen) conditions. The cells stained strongly for markers of adult mesenchymal stem cells, and a high number of cells were also positive for the pericyte marker 3G5. The cells showed a chondrogenic response in cell aggregate cultures and, in lowered oxygen, there was increased matrix accumulation of proteoglycan, but less cell proliferation. In hypoxia, there was increased expression of key transcription factor SOX6, and of collagens II and XI, and aggrecan. Pericytes are a candidate stem cell in many tissue, and our results show that bone marrow‐derived mesenchymal stem cells express the pericyte marker 3G5. The response to chondrogenic culture in these cells was enhanced by lowered oxygen tension. This has important implications for tissue engineering applications of bone marrow‐derived stem cells. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:834–840, 2010
Mesenchymal stem cells accelerate bone allograft incorporation in the presence of diabetes mellitus
Authors: Breitbart Eric A. , Meade Sharonda , Azad Vikrant , Yeh Sloane , Al‐Zube Loay , Lee Yee‐Shuan , Benevenia Joseph , Arinzeh Treena Livingston , Lin Sheldon S.
Published: January 2010

Allograft (Allo) incorporation in the presence of a systemic disease like diabetes mellitus (DM) is becoming a major issue in the orthopedic community. Mesenchymal stem cells (MSC) are multipotent stem cells that may be derived from adult, whole bone marrow and have been shown to induce bone formation in segmental defects when combined with the appropriate carrier/scaffold. The objectives of this study were to analyze the effect of DM upon Allo incorporation in a segmental rat femoral defect and to also investigate MSC augmentation of Allo incorporation. Segmental (5 mm) femoral defects were created in non‐DM and DM rats and treated with Allo containing demineralized bone matrix (DBM) or DBM with MSC augmentation. Histological scoring at 4 weeks demonstrated less mature bone in the DM/DBM group compared to its non‐DM counterpart (p < 0.001). However, there was significantly more mature bone in the DM/MSC group when compared to the DM/DBM group at both 4 and 8 weeks (p < 0.001 and p = 0.004). Furthermore, significantly more bone formation was observed in the DM/MSC group compared to the DM/DBM group at the 4‐week time point (p < 0.001). The results of this study suggest that MSC are a potential adjunct for bone regeneration when implanted in an orthotopic site in the presence of DM. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:942–949, 2010
Nano‐scale topography of bearing surface in advanced alumina/zirconia hip joint before and after severe exposure in water vapor environment
Authors: Pezzotti Giuseppe , Saito Takuma , Padeletti Giuseppina , Cossari Pierluigi , Yamamoto Kengo
Published: January 2010

The aim of this study was to perform a surface morphology assessment with nanometer scale resolution on femoral heads made of an advanced zirconia toughened alumina (ZTA) composite. Femoral heads were characterized to a degree of statistical accuracy in the as‐received state and after exposures up to 100 h in severe vapor‐moist environment. Surface screening was made using an atomic force microscope (AFM). Scanning was systematically repeated on portions of surface as large as several tens of micrometers, randomly selected on the head surface, to achieve sufficient statistical reliability without lowering the nanometer‐scale spatial resolution of the roughness measurement. No significant difference was found in the recorded values of surface roughness after environmental exposure (at 134°C, under 2 bar), which was always comparable to that of the as‐received head. Surface roughness safely lay <10 nm after environmental exposures up to 100 h, which corresponded to an exposure time in vivo of several human lifetimes (i.e., according to an experimentally derived thermal activation energy). In addition, the roughness results were significantly (about one order of magnitude) lower as compared to those recorded on femoral heads made of monolithic zirconia tested under the same conditions. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:762–766, 2010
Hyaluronan modulates cell proliferation and mRNA expression of adhesion‐related procollagens and cytokines in glenohumeral synovial/capsular fibroblasts in adhesive capsulitis
Authors: Nago Masaru , Mitsui Yasuhiro , Gotoh Masafumi , Nakama Kenjirou , Shirachi Isao , Higuchi Fujio , Nagata Kensei
Published: January 2010

There is a growing body of evidence supporting the use of hyaluronan (HA) in patients with adhesive capsulitis of the shoulder, although the mechanisms of the effect have not yet been clarified. This in vitro study examined the effects of HA on glenohumeral synovial/capsular fibroblasts (GSCFs) from patients with adhesive capsulitis of the shoulder. The study subjects were seven patients with primary or secondary adhesive capsulitis of the shoulder (average age: 55 years; range: 42–65). Synovial/capsular specimens were obtained from the rotator interval of each patient during arthroscopy. Part of the tissue specimen was used for histological analysis. The remainder of the tissue was prepared for cell culture. Various concentrations of HA (0.0–4.0 mg/mL) were added to the monolayer‐cultured GSCFs from these patients. Histological analysis consistently demonstrated chronic nonspecific inflammation with synovial hyperplasia, proliferation of vessels and fibroblasts, and increased amount of extracellular matrix. Treatment with HA at various concentrations significantly and dose‐dependently inhibited cell proliferation and decreased the expression levels of mRNA for adhesion‐related procollagens and cytokines. Pretreatment with OS/37 did not reverse the inhibitory effect of HA. These results suggest that HA modulates cell proliferation and expression of the mRNA of adhesion‐related procollagens and cytokines in GSCFs, preventing the progression of adhesion formation in patients with adhesive capsulitis of the shoulder. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:726–731, 2010
A nonrandomized comparison of potassium titanyl phosphate and CO2 laser fiber stapedotomy for primary otosclerosis with the otology‐neurotology database
Authors: Vincent Robert , Grolman Wilko , Oates John , Sperling Neil , Rovers Maroeska
Published: January 2010

Objectives/Hypothesis:

To compare short‐term hearing results in patients undergoing laser stapedotomy for primary otosclerosis using either the flexible potassium titanyl phosphate (KTP) or CO2 laser fiber.

Study Design:

Prospective nonrandomized clinical study at a tertiary referral center.

Methods:

Two hundred fourteen patients undergoing 214 stapedotomies for otosclerotic stapes fixation were enrolled in this study from January 2008 to January 2010. Comparative analyses were made between a group of 107 patients who underwent stapedotomy with the flexible KTP laser fiber and 107 patients who underwent stapedotomy with the flexible CO2 laser fiber. Preoperative and postoperative audiometric evaluation at 3 months using conventional audiometry, namely, air‐bone gap (ABG), bone‐conduction thresholds, and air‐conduction thresholds, were assessed.

Results:

In the KTP laser group the postoperative ABG was 4.3 dB compared to 3 dB in the CO2 group, which is a mean difference of 1.3 dB (95% confidence interval [CI], −0.3 to 2.8; P = .10). Of the patients from the KTP group, 92% had a postoperative ABG of 10 dB or less, as compared to 97% in the CO2 group (mean difference 5%; 95% CI, –10 to 1; P = .14). The postoperative ABG at 4 kHz was 4.9 dB in the KTP and 2.2 dB in the CO2 group, which is a mean difference of 2.7 dB (95% CI, 0.6–4.7, P = .01). No sensorineural hearing loss was reported.

Conclusions:

The use of the CO2 laser fiber appears to be associated with slightly better hearing results than the KTP laser fiber, especially when assessed at the 4 kHz frequency. Laryngoscope, 2010
Molecular characterization of the Gγ‐globin‐Tag transgenic mouse model of hormone refractory prostate cancer: Comparison to human prostate cancer
Authors: Calvo Alfonso , Perez‐Stable Carlos , Segura Victor , Catena Raúl , Guruceaga Elizabeth , Nguewa Paul , Blanco David , Parada Luis , Reiner Teresita , Green Jeffrey E.
Published: January 2010

BACKGROUND

Prostate cancer (PrCa) has a high incidence in Western countries and at present, there is no cure for hormone refractory prostate cancer. Transgenic mouse models have proven useful for understanding mechanisms of prostate carcinogenesis. The characterization of genetically modified mouse PrCa models using high‐throughput genomic analyses provides important information to guide appropriate experiment applications for such model.

METHODS

We have analyzed the transcriptome of the hormone refractory and highly metastatic Fetal Globin‐SV40/T‐antigen (Gγ‐globin‐Tag) transgenic mouse model for PrCa compared to normal mouse prostate tissue. Gene expression patterns found in Gγ‐globin‐Tag mouse prostate tumors were compared with publicly available human localized and metastatic prostate tumors (GEO accession # GSE3325) through hierarchical cluster analysis, Pearson's rank correlation coefficient, and Self Organizing Feature Maps (SOM) analyses.

RESULTS

Gγ‐globin‐Tag tumors clustered closely with human metastatic tumors and gene expression patterns had a significant correlation (P < 0.01), unlike human localized primary tumors (P > 0.6). Bioinformatic analyses identified deregulated genetic pathways and networks in Gγ‐globin‐Tag tumors, which displayed similarities to alterations in human PrCa. Changes in the expression of genes involved in DNA replication and repair (Rb1, p53, Myc, PCNA, DNMT3A) and growth factor signaling pathways (TGFβ2, ERK1/2, NRas, and Notch1) are deregulated in the Gγ‐globin‐Tag tumors, suggesting their key role in the oncogenic process. Identification of an enrichment of putative binding sites for transcription factors revealed eight transcription factors that may be important in Gγ‐globin‐Tag carcinogenesis, including SP1, NF‐Y, CREB, Elk1, and E2F. Novel genes related to microtubule regulation were also identified in Gγ‐globin‐Tag tumors as potentially important candidate targets for PrCa. Overexpression of stathmin‐1, whose expression was increased in human metastatic prostate tumors, was validated in Gγ‐globin‐Tag tumors by immunohistochemistry. This protein belongs to the SV40/T‐antigen cancer signature identified in previous studies in prostate, breast, and lung cancer mouse models.

CONCLUSIONS

Our results show that the Gγ‐globin‐Tag model for hormone refractory PrCa shares important features with aggressive, metastatic human PrCa. Given the role of stathmin‐1 in the destabilization of microtubles and taxane resistance, the Gγ‐globin‐Tag model and other SV40/T‐antigen driven transgenic models may be useful for testing potential therapies directed at stathmin‐1 in human prostate tumors. Prostate 70: 630–645, 2010. Published 2010 Wiley‐Liss, Inc.
Prolonged treatment with bicalutamide induces androgen receptor overexpression and androgen hypersensitivity
Authors: Kawata Hiromitsu , Ishikura Nobuyuki , Watanabe Miho , Nishimoto Ayako , Tsunenari Toshiaki , Aoki Yuko
Published: January 2010

BACKGROUND

Various hormone refractory prostate cancer cell models have been established with androgen depletion and have helped to clarify the mechanism for the transition into androgen‐depletion independent status. However, the mechanism of bicalutamide resistance remains unclear because few cell models have been generated.

METHODS

We generated a bicalutamide‐resistant subline, LNCaP‐BC2, from LNCaP after prolonged treatment with bicalutamide. Androgen and/or bicalutamide responsiveness for proliferation and prostate‐specific antigen (PSA) secretion were examined in vitro and in vivo. Testosterone and dihydrotestosterone (DHT) levels in xenografted tumors were analyzed by liquid chromatography‐tandem mass spectrometry. Androgen receptor (AR) gene mutation and amplification and AR and pAR210 expression were determined.

RESULTS

LNCaP‐BC2 did not grow in an androgen‐depleted medium and proliferation was stimulated in a tenfold lower concentration of androgen than that of LNCaP. LNCaP‐BC2 grew in castrated male mice, and the DHT level in grafted LNCaP‐BC2 tumors was 7.7‐fold lower than in LNCaP tumors. Bicalutamide stimulated LNCaP‐BC2 proliferation and PSA secretion in vitro and the antitumor activity of bicalutamide against LNCaP‐BC2 was weaker than that of LNCaP in vivo. Additional AR mutation and AR gene amplification were not detected in LNCaP‐BC2, but AR and pAR210 expression and PSA secretion in LNCaP‐BC2 were higher than in LNCaP.

CONCLUSIONS

Bicalutamide‐resistant LNCaP‐BC2 exhibited AR overexpression and hypersensitivity to low levels of androgen. Our data suggests that AR overexpression is a significant mechanism of bicalutamide resistance similar to resistance from chronic androgen depletion. In addition, pAR210 overexpression could be a potential mechanism for hypersensitivity to low androgen in LNCaP‐BC2. Prostate 70: 745–754, 2010. © 2010 Wiley‐Liss, Inc.
A queuing-based model for optimal dimension of service firms
Authors: Parra-Frutos Isabel
Published: January 2010

This paper examines a stochastic model to determine optimal pricing, waiting time, output, and sizing decisions for service firms which compete on time in an uncertain environment. Sizing decisions concern optimal service capacity and maximum physical waiting room (with a given probability). Customers are sensitive to money price and expected waiting time. The firm, modeled as an M/M/1 queue, is assumed to be a full price taker as a result of the stochastic version of the perfect competition assumption. Firm costs function includes fixed and variable costs. We initially fix the service rate and obtain a closed-form expression for the waiting time, price, output and waiting room which lead to maximize the net revenue. Subsequently, we obtain first-order conditions for the profit maximizing service capacity. We find that an optimal capacity may exist when service capacity costs are strictly convex. When capacity costs are linear or concave, an optimal capacity does not exist, and it is possible to obtain higher expected profits by increasing service capacity, as the time competition principle states. However, in the linear case we find a failure of that principle, which is, there is a limit in speeding up processes.
Prevention of postpartum hemorrhage at home birth in Afghanistan
Authors: Sanghvi Harshadkumar , Ansari Nasratullah , Prata Ndola J.V. , Gibson Hannah , Ehsan Aftab T. , Smith Jeffrey M.
Published: January 2010

Objective

To test the safety, acceptability, feasibility, and effectiveness of community‐based education and distribution of misoprostol for prevention of postpartum hemorrhage at home birth in Afghanistan.

Methods

A nonrandomized experimental control design in rural Afghanistan.

Results

A total of 3187 women participated: 2039 in the intervention group and 1148 in the control group. Of the 1421 women in the intervention group who took misoprostol, 100% correctly took it after birth, including 20 women with twin pregnancies. Adverse effect rates were unexpectedly lower in the intervention group than in the comparison group. Among women in the intervention group, 92% said they would use misoprostol in their next pregnancy. In the intervention area where community‐based distribution of misoprostol was introduced, near‐universal uterotonic coverage (92%) was achieved compared with 25% coverage in the control areas.

Conclusion

In Afghanistan, community‐based education and distribution of misoprostol is safe, acceptable, feasible, and effective. This strategy should be considered for other countries where access to skilled attendance is limited.
The Crucifixion Conundrum and the Santa Sabina Doors
Authors: Sheckler Allyson Everingham , Winn Leith Mary Joan
Published: January 2010

The earliest extant public image of the crucifixion of Christ appears on a single relief panel on the early-fifth-century wooden doors of the Church of Santa Sabina on the Aventine Hill in Rome (figs. 1 and 2). General scholarly consensus dates the construction of the church to the pontificate of Pope Celestine I (422–433 c.e.) as stated in the surviving inscription on the church's interior west wall.1 Construction probably continued into the pontificate of Sixtus III (432–440 c.e.) when the church was formally consecrated.2 Although in the ensuing centuries the image of the Crucified Christ—the Crucifix—attained canonical status, scholars seeking precedents for Santa Sabina's crucifixion scene have failed to determine its pedigree satisfactorily within the Christian artistic tradition. We propose that broadening our understanding of artistic prototypes for the Santa Sabina crucifixion image to include both formal and theological elements allows for a more nuanced and promising investigation.
Determining maximum load carrying capacity of planar flexible-link robot: closed-loop approach
Authors: Korayem M. H. , Haghighi R. , Korayem A. H. , Nikoobin A. , Alamdari A.
Published: January 2010

Maximum load carrying capacity (MLCC) of flexible robot manipulators is computed based on closed-loop approach. In open-loop approach, controller is not considered, so the end effector deviation from the predefined path is significant and the accuracy constraint restrains the maximum payload before actuators go into saturation mode. In order to improve the MLCC, a method based on closed-loop strategy is presented. Since in this case the accuracy is improved the actuators constraint is not a major concern and full power of actuators can be used. Since controller can play an important role in improving the maximum payload, a sliding mode based partial feedback linearization controller is designed. Furthermore, a fuzzy variable layer is used in sliding mode design to boost the performance of the controller. However, the control strategy required measurements of elastic variables velocity that are not conveniently measurable. So a nonlinear observer is designed to estimate these variables. Stability analysis of the proposed controller and state observer are performed on the basis of Lyapunov's direct method. In order to verify the effectiveness of the presented method, simulation is done for a two-link flexible manipulator. The obtained maximum payload in open-loop and closed-loop cases is compared and the superiority of the method is illustrated and the results are discussed.
High permeability and high permittivity heterostructures for the miniaturization of Radiofrequency components
Authors: Bènevent Evangéline , Garello Kevin , Cros Dominique , Viala Bernard
Published: January 2010

This paper discusses on the miniaturization of radiofrequency (RF) front-end components such as half-wavelength resonators based on new magneto-dielectric heterostructures combining high permeability (µ = 150–250) and high permittivity (ε = 18–150). Size reduction is evaluated by means of 2-cm-long coplanar waveguides realized with silicon technology and having a resonance frequency of about 3 GHz. The experimental results show a physical length reduction of 11.2% due to the dielectric contribution (ε = 18) and 14.8% by cumulating dielectric and magnetic effects (ε = 18 and µ = 150). These results are significant with respect to the moderate thickness of the preliminary material used here (only 150 nm). In a second part, a predictive model is proposed with µ and ε as variables. When adjusting the material properties in a realistic way (µ = 250 and ε = 150), the model predicts size reduction of ~50% for the same thickness. Larger values can be expected with increasing the film thickness.
Characterization of a loaded high impedance surface
Authors: Linot Fabrice , Begaud Xavier , Soiron Michel , Renard Christian , Labeyrie Michèle
Published: January 2010

A high impedance surface (HIS) consisting of metallic square patches electrically connected one to each other with resistors is shown. Tunability of the absorption factor is achieved by the resistor value. The absorbing band of the loaded HIS is determined by the phase of the signal reflected by this structure. The main contribution of the paper is to demonstrate the absorption behavior over a wide range of incidence angle for both Transverse Electric (TE) and Transverse Magnetic (TM) polarizations. Using an equivalent circuit the resistor effect is investigated. It is shown that at resonance, the judicious choice of the resistor may lead to a significant absorption. The use of a waveguide simulator to characterize the performance of the loaded HIS is investigated. These methods have been used to design an ultra-thin absorber about λ8.4 GHz/35 thick.
Reorganization of polar cap patches through shears in the background plasma convection
Authors: Hosokawa K. , St‐Maurice J.‐P. , Sofko G. J. , Shiokawa K. , Otsuka Y. , Ogawa T.
Published: January 2010

On the night of December 20, 2006, 630 nm airglow images obtained by an all‐sky camera at Resolute Bay, Canada (74.73°N, 265.07°E; altitude adjusted corrected geomagnetic (AACGM) latitude 82.9°) showed the passage of successive polar cap patches. Shortly after convection came to a temporary halt, one of the patches was reorganized into two substructures in approximately 8 min. The two‐dimensional background ionospheric convection pattern measured using the newly deployed PolarDARN radar at Rankin Inlet (62.82°N, 93.11°W; AACGM latitude 72.96°) showed that a velocity shear of approximately 120 m s−1/340 km suddenly appeared in the vicinity of the patch at the time of reorganization. A qualitative analysis of the relationship between the magnitude of the velocity shear and the distance between the divided patches indicates that the shear in the background plasma convection velocity significantly contributed to the reorganization of the patch. This shear structure appeared soon after a southward turning of the interplanetary magnetic field (IMF) and was probably associated with the reconfiguration of the convection pattern from a pre‐existing northward‐oriented IMF pattern to a southward‐oriented one. The present observations indicate that the reconfiguration/deformation of patches because of a shear in the background convection field, especially reorganization of patches into smaller substructures, may play an important role in the rapid structuring of patches.
Jovian slow‐drift shadow events
Authors: Koshida Tomonori , Ono Takayuki , Iizima Masahide , Kumamoto Atsushi
Published: January 2010

We observed negative spectra of quenched background L burst emissions with a negative drift rate of −5 MHz s−1 by using a waveform receiver developed by Koshida [2009]. We named this phenomenon a slow‐drift shadow event (SDS event). The leading and trailing edges of these SDS events showed a sudden change in their drift rates at similar frequencies. Wavy SDS‐like phenomena were also observed with a frequency of 15 Hz. Both S bursts and the ionospheric Alfvén resonator have similar characteristic frequencies. The local potential jumps were discovered near the Jovian decametric (DAM) source regions by Hess et al. (2007b, 2009). SDS slope changes may be related to similar features. We have attempted to quantitatively estimate the background plasma densities by assuming that the background L burst emissions were generated by cyclotron maser instability (CMI) and that the SDS events were related to the Alfvén wave. The estimated background plasma densities were in the range of 5 × 106–2 × 107 cm−3. Since fp/fc ≈ 0.87–1.7, the CMI must be quenched. This give rises to the question of what induced the SDS events.
Discrimination of a preparatory stage leading to M7 characteristic earthquakes off Ibaraki Prefecture, Japan
Authors: Matsumura Shozo
Published: January 2010

An M7.0 earthquake struck off Ibaraki Prefecture, Japan, on 8 May 2008. This event was interpreted as belonging to a characteristic earthquake series fracturing the same asperities on the upper boundary of the Pacific plate with a quasi‐regular interval of about 22 years. The previous M7.0 occurred in 1982, 26 years before the latest one. I examined the background microseismicity changes preceding these two events by drawing maps of earthquake frequency ratios between two successive periods, and I found a significant similarity between them. This similarity could be expressed numerically by calculating correlation coefficients between the two maps. Surveying the temporal transition of the correlation coefficients, I confirmed that the similarity appeared only for the combination of those maps just before two characteristic earthquakes; it never appeared in the other cases. This result implies the existence and repetition of a typical preparatory stage leading to the characteristic earthquake, which might be caused by a quasi‐static slip on minor asperities in a hierarchical constitution and which forms a specific pattern of seismicity change. This evidence makes it possible to propose a definitive procedure for the practical prediction of the next characteristic earthquake, which is anticipated to occur around 2030. Two kinds of correlation coefficients (rA and rB) are calculated by treating each seismicity change map just before the 1982 and 2008 events as references. When both rA and rB exceed the prefixed threshold r0, it is possible to announce the time of immediate occurrence of the target earthquake.
Evolutionary divergence and biogeography of sympatric niche-differentiated bacterial populations
Authors: Oakley Brian B , Carbonero Franck , van der Gast Christopher J , Hawkins Robert J , Purdy Kevin J
Published: January 2010

Using multiple lines of evidence from denaturing gradient gel electrophoresis, environmental sequences and TaqMan quantitative PCR assays targeting a functional gene for sulfate respiration (dsr) affiliated with the geochemically important genus Desulfobulbus, we revealed strongly restricted distributions of specific genotypes and populations correlated with sampling position along an estuarine gradient free of dispersal barriers. Evidence of evolutionary divergence of populations was provided by three complementary analyses. First, analysis of molecular variance rejected the null hypothesis that genetic diversity within each sampling site was not significantly different than that of all sites pooled together (P<0.0001). Second, UniFrac and Parsimony tests showed phylogenetic clustering of sampling sites was highly significant (P<0.001). Third, pairwise FST statistics showed significant evolutionary divergence of populations based on the location in the estuary. To test the hypothesis that environmental niche-driven evolutionary divergence can create and maintain microbial biogeography, we used both statistical inference and an experimental manipulation to assess the independent effects of environment and geography. Significant effects of each on genotype distributions and population divergence supported the hypothesis. Our data are consistent with both sympatric and parapatric models of speciation, and suggest niche partitioning can contribute to evolutionary divergence and observable biogeographic patterns in microbial communities even among closely related taxa at limited spatial scales without significant barriers to dispersal.
Longitudinal Adaptations to Very Low–carbohydrate Weight‐reduction Diet in Obese Rats: Body Composition and Glucose Tolerance
Authors: Axen Kathleen V. , Axen Kenneth
Published: January 2010

Longitudinal effects of a very low–carbohydrate (VLC) and a calorie‐matched high‐carbohydrate (HC) weight reduction diet were compared in dietary obese Sprague–Dawley rats exhibiting impaired glucose tolerance and insulin resistance. Obese rats were divided into weight‐matched groups: (i) VLC rats consumed an energy‐restricted 5% carbohydrate, 60% fat diet for 8 weeks, (ii) HC rats consumed an isocaloric 60% carbohydrate, 15% fat diet, and (iii) HF rats consumed a high‐fat diet ad libitum. HC and VLC rats showed similar reductions in body fat and hepatic lipid at the midpoint of the weight‐reduction program, indicating effects due to energy deficit. At the end point, however, HC rats showed greater reductions in total and percent body fat, hepatic lipid and intramuscular lipid than did VLC rats, suggesting that diet composition induced changes in the relative efficiencies of the HC and VLC diets over time. HC rats showed marked improvement in glucose tolerance at the midpoint and end point, whereas VLC rats showed no improvement. Impaired glucose tolerance in VLC rats at the end point was due to insulin resistance and an attenuated insulin secretory response. Glucose tolerance in energy‐restricted rats correlated negatively with hepatic and intramuscular lipid levels, but not visceral or total fat mass. These findings demonstrate that adaptations to diet composition eventually enabled HC rats to lose more body fat than VLC rats even though energy intakes were equal, and suggest that the elevated levels of hepatic and intramuscular lipid associated with VLC diets might predispose to insulin resistance and impaired glucose tolerance despite weight loss.
Meta‐analysis Added Power to Identify Variants in FTO Associated With Type 2 Diabetes and Obesity in the Asian Population
Authors: Liu Yun , Liu Zhe , Song Yiqing , Zhou Daizhan , Zhang Di , Zhao Teng , Chen Zhuo , Yu Lan , Yang Yifeng , Feng Guoyin , Li Jun , Zhang Jie , Liu Simin , Zhang Zuofeng , He Lin , Xu He
Published: January 2010

Several common variants in the intron 1 of FTO (fat mass and associated obesity) gene have been reliably associated with BMI and obesity in European populations. We analyzed two variants (rs9939609 and rs8050136) in 4,189 Chinese Han individuals and conducted a meta‐analysis of published studies in Asian population to investigate whether these variants are associated with type 2 diabetes (T2D) and obesity in Asian population. In this study, both the minor allele A of rs9939609 and the minor allele A of rs805136 were associated with increased risk of T2D, independent of measures of BMI; the odds ratios (ORs) per copy of the risk allele were 1.19 for rs9939609 (95% confidence interval (CI), 1.04–1.37; P = 0.01) and 1.22 for rs8050136 (95% CI, 1.07–1.40; P = 0.004) after adjusting for age, sex, and BMI. Our results also showed association with risk of obesity (rs9939609: OR = 1.39 (95% CI 1.04–1.85), P = 0.02; rs8050136: OR = 1.45 (95% CI 1.09–1.93), P = 0.01) but no association with overweight. These results were consistent with the pooled results from our meta‐analysis study (for diabetes, rs8050136, P = 1.3 × 10−3; rs9939609, P = 9.8 × 10−4; for obesity, rs8050136, P = 2.2 × 10−7; rs9939609, P = 9.0 × 10−9). Our findings indicate that the two variants (rs9939609 and rs8050136) in the FTO gene contribute to obesity and T2D in the Asian populations.
Cerium Triflate: An Efficient and Recyclable Catalyst for Chemoselective Thioacetalization of Carbonyl Compounds under Solvent-Free Conditions
Authors: Kumar Anil , Rao M. Sudershan , Kameshwara Rao V.
Published: January 2010

A simple and efficient chemoselective thioacetalization of carbonyl compounds has been achieved using Ce(OTf)3 (10 mol-%) as a catalyst under solvent-free conditions. Advantages of the methodology include very short reaction times, excellent yields, the catalytic use of a water tolerant Lewis acid, and simple recovery and reuse of the catalyst.
UBE2S drives elongation of K11-linked ubiquitin chains by the Anaphase-Promoting Complex
Authors: Wu Tao , Merbl Yifat , Huo Ying , Gallop Jennifer L. , Tzur Amit , Kirschner Marc W.
Published: January 2010

The Anaphase-Promoting Complex (APC) is an E3 ubiquitin ligase that regulates mitosis and G1 by sequentially targeting cell-cycle regulators for ubiquitination and proteasomal degradation. The mechanism of ubiquitin chain formation by APC and the resultant chain topology remains controversial. By using a single-lysine APC substrate to dissect the topology of ubiquitinated substrates, we find that APC-catalyzed ubiquitination has an intrinsic preference for the K11 linkage of ubiquitin that is essential for substrate degradation. K11 specificity is determined by an E2 enzyme, UBE2S/E2-EPF, that elongates ubiquitin chains after the substrates are pre-ubiquitinated by UbcH10 or UbcH5. UBE2S copurifies with APC; dominant-negative Ube2S slows down APC substrate degradation in functional cell-cycle extracts. We propose that Ube2S is a critical, unique component of the APC ubiquitination pathway.
Energy levels, radiative rates and electron impact excitation rates for transitions in Li-like N V, F VII, Ne VIII and Na IX
Authors: Aggarwal K M , Keenan F P , Heeter R F
Published: January 2010

In this paper, we report calculations of energy levels, radiative rates and electron impact excitation rates for transitions in Li-like N V, F VII, Ne VIII and Na IX. The general-purpose relativistic atomic structure package (GRASP) is adopted for calculating energy levels and radiative rates, while for determining the collision strengths and subsequently the excitation rates, the Dirac atomic
R
-matrix code (DARC) and the flexible atomic code (FAC) are used. Oscillator strengths, radiative rates and line strengths are reported for all E1, E2, M1 and M2 transitions among the lowest 24 levels of N V, F VII, Ne VIII and Na IX. Collision strengths have been averaged over a Maxwellian velocity distribution and the effective collision strengths so obtained are reported over a wide temperature range below 106.6 K. Additionally, lifetimes are also reported for all calculated levels of the above four ions.
NPP-16/Nup50 Function and CDK-1 Inactivation Are Associated with Anoxia-induced Prophase Arrest in Caenorhabditis elegans
Authors: Hajeri Vinita A. , Little Brent A. , Ladage Mary L. , Padilla Pamela A.
Published: January 2010

Oxygen, an essential nutrient, is sensed by a multiple of cellular pathways that facilitate the responses to and survival of oxygen deprivation. The Caenorhabditis elegans embryo exposed to severe oxygen deprivation (anoxia) enters a state of suspended animation in which cell cycle progression reversibly arrests at specific stages. The mechanisms regulating interphase, prophase, or metaphase arrest in response to anoxia are not completely understood. Characteristics of arrested prophase blastomeres and oocytes are the alignment of condensed chromosomes at the nuclear periphery and an arrest of nuclear envelope breakdown. Notably, anoxia-induced prophase arrest is suppressed in mutant embryos lacking nucleoporin NPP-16/NUP50 function, indicating that this nucleoporin plays an important role in prophase arrest in wild-type embryos. Although the inactive form of cyclin-dependent kinase (CDK-1) is detected in wild-type–arrested prophase blastomeres, the inactive state is not detected in the anoxia exposed npp-16 mutant. Furthermore, we found that CDK-1 localizes near chromosomes in anoxia-exposed embryos. These data support the notion that NPP-16 and CDK-1 function to arrest prophase blastomeres in C. elegans embryos. The anoxia-induced shift of cells from an actively dividing state to an arrested state reveals a previously uncharacterized prophase checkpoint in the C. elegans embryo.
Meta-Analysis of the Effects of Triazole-Based Fungicides on Wheat Yield and Test Weight as Influenced by Fusarium Head Blight Intensity
Authors: Paul P. A. , McMullen M. P. , Hershman D. E. , Madden L. V.
Published: January 2010

Multivariate random-effects meta-analyses were conducted on 12 years of data from 14 U.S. states to determine the mean yield and test-weight responses of wheat to treatment with propiconazole, prothioconazole, tebuconazole, metconazole, and prothioconazole+tebuconazole. All fungicides led to a significant increase in mean yield and test weight relative to the check (D; P < 0.001). Metconazole resulted in the highest overall yield increase, with a D of 450 kg/ha, followed by prothioconazole+tebuconazole (444.5 kg/ha), prothioconazole (419.1 kg/ha), tebuconazole (272.6 kg/ha), and propiconazole (199.6 kg/ha). Metconazole, prothioconazole+tebuconazole, and prothioconazole also resulted in the highest increases in test weight, with D values of 17.4 to 19.4 kg/m3, respectively. On a relative scale, the best three fungicides resulted in an overall 13.8 to 15.0% increase in yield but only a 2.5 to 2.8% increase in test weight. Except for prothioconazole+tebuconazole, wheat type significantly affected the yield response to treatment; depending on the fungicide, D was 110.0 to 163.7 kg/ha higher in spring than in soft-red winter wheat. Fusarium head blight (FHB) disease index (field or plot-level severity) in the untreated check plots, a measure of the risk of disease development in a study, had a significant effect on the yield response to treatment, in that D increased with increasing FHB index. The probability was estimated that fungicide treatment in a randomly selected study will result in a positive yield increase (p+) and increases of at least 250 and 500 kg/ha (p250 and p500, respectively). For the three most effective fungicide treatments (metconazole, prothioconazole+tebuconazole, and prothioconazole) at the higher selected FHB index, p+ was very large (e.g., ≥0.99 for both wheat types) but p500 was considerably lower (e.g., 0.78 to 0.92 for spring and 0.54 to 0.68 for soft-red winter wheat); at the lower FHB index, p500 for the same three fungicides was 0.34 to 0.36 for spring and only 0.09 to 0.23 for soft-red winter wheat.
Lateralization of magnetic compass orientation in pigeons
Authors: Wilzeck Christiane , Wiltschko Wolfgang , Güntürkün Onur , Wiltschko Roswitha , Prior Helmut
Published: January 2010

The aim of our study was to test for lateralization of magnetic compass orientation in pigeons. Having shown that pigeons are capable of learning magnetic compass directions in an operant task, we wanted to know whether the brain hemispheres contribute differently and how the lateralization pattern relates to findings in other avian species. Birds that had learnt to locate food in an operant chamber by means of magnetic directions were tested for lateralization of magnetic compass orientation by temporarily covering one eye. Successful orientation occurred under all conditions of viewing. Thus, pigeons can perceive and process magnetic compass directions with the right eye and left brain hemisphere as well as the left eye and right brain hemisphere. However, while the right brain hemisphere tended to confuse the learned direction with its opposite (axial response), the left brain hemisphere specifically preferred the correct direction. Our findings demonstrate bilateral processing of magnetic information, but also suggest qualitative differences in how the left and the right brain deal with magnetic cues.
Microscale laser surgery reveals adaptive function of male intromittent genitalia
Authors: Polak Michal , Rashed Arash
Published: January 2010

The leading hypothesis for the evolution of male genital complexity proposes that genital traits evolve in response to post-insemination sexual selection; that is, via cryptic female choice or sperm competition. Here, we describe a laser ablation technique for high-precision manipulation of microscale body parts of insects, and employ it to discern the adaptive function of a rapidly evolving and taxonomically important genital trait: the intromittent claw-like genital spines of maleDrosophila bipectinataDuda. We demonstrate experimentally and unambiguously that the genital spines of this species function to mechanically couple the genitalia together. The excision of the spines by laser ablation sharply reduced the ability of males both to copulate and to compete against rival males for mates. When spineless males did succeed to copulate, their insemination success and fertilization rate were not statistically different from controls, at odds with the post-insemination sexual selection hypothesis of genital function and evolution. The results provide direct experimental support for the hypothesis that genital traits evolve in response to sexual selection occurring prior to insemination.