bluuebunny/crossref_metadata_2025 huggingface dataset:
High hip fracture risk in men with severe aortic calcification: MrOS study
Authors: Szulc Pawel , Blackwell Terri , Schousboe John T , Bauer Douglas C , Cawthon Peggy , Lane Nancy E. , Cummings Steven R , Orwoll Eric S , Black Dennis M , Ensrud Kristine E
Published: August 2013

A significant link between cardiovascular disease and osteoporosis is established in postmenopausal women, but data for men are scarce. We tested the hypothesis that greater severity of abdominal aortic calcification (AAC) was associated with an increased risk of nonspine fracture in 5994 men aged ≥65 years. AAC was assessed on 5400 baseline lateral thoracolumbar radiographs using a validated visual semiquantitative score. Total hip bone mineral density (BMD) was measured using dual-energy X-ray absorptiometry. Incident nonspine fractures were centrally adjudicated. After adjustment for age, body mass index (BMI), total hip BMD, fall history, prior fracture, smoking status, comorbidities, race, and clinical center, the risk of nonspine fracture (n = 805) was increased among men with higher AAC (hazard ratio [HR] quartile 4 [Q4] [AAC score ≥9] versus quartile 1 [Q1] [0–1], 1.36; 96% confidence interval [CI], 1.10–1.68). This association was due to an increased risk of hip fracture (n = 178) among men with higher AAC (HR Q4 versus Q1, 2.33; 95% CI, 1.41–3.87). By contrast, the association between AAC and the risk of nonspine, nonhip fracture was weaker and not significant (HR Q4 versus Q1, 1.22; 95% CI, 0.96–1.55). The findings regarding higher AAC and increased risk of fracture were not altered in additional analyses accounting for degree of trauma, estimated glomerular filtration rate, presence of lumbar vertebral fractures (which may bias AAC assessment), preexisting cardiovascular disease, ankle brachial index, or competing risk of death. Thus, in this large cohort of elderly men, greater AAC was independently associated with an increased risk of hip fracture, but not with other nonspine fractures. These findings suggest that AAC assessment may be a useful method for identification of older men at high risk of hip fracture. © 2014 American Society for Bone and Mineral Research.
Stochastic structure determination for conformationally flexible heterogenous molecular clusters: Application to ionic liquids
Authors: Addicoat Matthew A. , Fukuoka Syou , Page Alister J. , Irle Stephan
Published: August 2013

We present a novel method that enables accurate and efficient computational determination of conformationally flexible clusters, “Kick3” This method uses stochastically generated structures in combination with fast quantum mechanical methods. We demonstrate the power of this method by elucidating the structure of ionic liquid (IL) ([xMIM+][
clusters (x = E, B, D, n = 1–10,15). Dispersion‐corrected, third‐order self‐consistent‐charge density‐functional tight‐binding (DFTB3) is shown to be a computationally efficient, yet reliable approximation to density functional theory for predicting and understanding IL structure and stability. The presented approach, therefore, enables the accurate and efficient screening of ILs with high potential toward practical applications, without recourse to more expensive quantum chemical methods. © 2013 Wiley Periodicals, Inc.
On the Possible Automorphism Groups of a Steiner Quintuple System of Order 21
Authors: Kolotoğlu Emre , Magliveras Spyros S.
Published: August 2013

A Steiner system is called a Steiner quintuple systems of order v. The smallest order for which the existence, or otherwise, of a Steiner quintuple system is unknown is 21. In this article, we prove that, if an S(4, 5, 21) exists, the order of its full automorphism group is 1, 2, 3, 4, 5, 6, 7, or 10.
Wind speed trends over Turkey from 1975 to 2006
Authors: Dadaser‐Celik Filiz , Cengiz Eda
Published: August 2013

This study examines the spatial and temporal dynamics of wind speeds over Turkey by analysing data from 206 weather stations for a 32‐year period (1975–2006). Trends in annual, seasonal, and monthly average wind speeds were determined using the Mann–Kendall trend test with the trend‐free pre‐whitening procedure. The strengths of trends were estimated by calculating the Sen's slope. The possible causes of wind speed changes were discussed. The analysis showed that the majority of the stations (73%) in Turkey had average wind speeds between 1.6 and 3.3 m s−1 during the 32‐year period. From 1975 to 2006, 72% of stations had downward trends in annual average wind speeds. Downward trends were statistically significant at the 0.05 level for 62%. Significant upward trends were detected in only 16% of 206 stations. The rate of change in annual average wind speed data was on average −0.014 m s−1 year−1. The trends detected in monthly average wind speed data were mostly downward with an average strength between −0.007 and −0.017 m s−1 year−1. The directions and strengths of wind speed trends identified for the 1975–2006 period over Turkey are similar to the trends detected in wind speeds in many other regions over the earth. The changes in wind speeds in Turkey are most strongly related with the changes in general circulation patterns and air temperatures. The effects associated with changes in surface roughness and data quality are minor compared to other two factors.
Effect of Polymer Structure and Incorporation of Nanoparticles on the Behavior of Syndiotactic Polypropylenes
Authors: Bejarano Julian , Benavente Rosario , Pérez Ernesto , Wilhelm Manfred , Quijada Raúl , Palza Humberto
Published: August 2013

A syndiotactic polypropylene (sPP) homopolymer and its copolymer with 1.4 mol% of norbornene (NsPP) are synthesized using a metallocene catalyst and the effect on the main properties of the addition of 4 wt% of either silica nanoparticles or multiwalled carbon nanotubes (CNTs) is studied. Important changes are observed in the thermal behavior of the different samples, primarily related to a strong nucleating effect of the nanofillers, much larger in CNTs than in silica, and to cold crystallization processes in the copoly­mer. Moreover, a rather relevant effect of the nanoparticles and their type, and of the cyclic comonomer is observed on the mechanical behavior of the polymer in the solid state. A strong effect of the kind of nanoparticle is also observed in the melt rheological properties of the samples, where again CNTs render larger changes than silica nanoparticles. On the contrary, oxygen permeation of sPP is unchanged with the addition of nanoparticles.

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Tunable Multiple‐Shape Memory Polyethylene Blends
Authors: Hoeher Robin , Raidt Thomas , Krumm Christian , Meuris Monika , Katzenberg Frank , Tiller Joerg C.
Published: August 2013

Shape memory polymers (SMPs) are an important class of smart materials. Usually, these polymers can be switched between two shapes. Recently, the possibility of switching more than two shapes was introduced for SMPs with relatively low strain storage capability. In this work, a lightly cross‐linked polyethylene blend comprising 80 wt% EOC, 15 wt% LDPE, and 5 wt% HDPE is prepared in order to obtain a tunable multiple‐shape memory polymer with high strain storage capacity. It is found that depending on the programming procedure, this SMP obtains a dual‐, triple‐, or quadruple‐shape memory effect, with well‐defined intermediate temporary shapes (retraction < 0.5% K−1) over a significantly broad temperature range (up to 30 K), large storable strains (up to 1700%), and nearly full recovery of all shapes (>98.9%).

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Nucleation‐Driven Kinetics of Poly(ethylene terephthalate) Melting
Authors: Vyazovkin Sergey , Yancey Benjamin , Walker Kahleah
Published: August 2013

The kinetics of poly(ethylene terephthalate) melting are studied by DSC and treated in the framework of a nucleation kinetic model. The study focuses on the temperature dependence of the effective activation energy of melting. A theoretical dependence is derived from the model and an experimental one from the Kissinger plot. It is demonstrated that the theoretical dependence satisfactorily predicts the experimental one and fitting the former to the latter can be used for estimating the surface free energy of a nucleus.

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The Influences of Cooperative Swelling and Coordination on Patterned Decoration of Gold on Block Copolymer Nanospheres
Authors: Wang Lu , Mei Shilin , Jin Zhaoxia
Published: August 2013

Ordered nanoring arrays are a new pattern of block copolymer thin films generated by spin‐coating of block copolymer reverse micelles on silicon substrates, which can further direct the formation of gold nanoring arrays on block copolymer thin films. Here, it is reported that the cooperation of swelling and coordination can influence the surface pattern of the block copolymer nanospheres. A hexagonally arranged dot pattern can be transformed into a ring pattern on polystyrene‐block‐poly(2‐vinylpyridine) nanospheres, and the new pattern can further direct the decoration of gold nanoparticles by balancing the swelling of the poly(2‐vinylpyridine) chains and the coordination effect between gold ions and the pyridine units.

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A new Brézis‐Gallouët‐Wainger inequality from the viewpoint of the real interpolation functors
Authors: Sawano Yoshihiro
Published: August 2013

The Brézis‐Gallouët‐Wainger inequality describes a subtle embedding property into . The relation between the Brézis‐Gallouët‐Wainger inequality and the real interpolation functor together with the sharpness of the results is discussed in the present paper. As our first main results shows, it turns out that there are two intermediate terms between and the logarithmic boundedness, which is supposed to be the right‐hand side of the Brézis‐Gallouët‐Wainger inequality. As the second result, the first result is extended to inequalities which reflect the meaning of the second index of Besov spaces and the interpolation theorem.
Design, Synthesis, and Application of Stimulus‐Sensing Biohybrid Hydrogels
Authors: Hotz Natascha , Wilcke Louisa , Weber Wilfried
Published: August 2013

A key feature of any living system is the ability to sense and react to the environmental stimuli. The biochemical characterization of the underlying biological sensors combined with advances in polymer chemistry has enabled the development of stimulus‐sensitive biohybrid materials that translate most diverse chemical and biological input into a precise change in material properties. In this review article, we first describe synthesis strategies of how biological and chemical polymers can functionally be interconnected. We then provide a comprehensive overview of how the different properties of biological sensor molecules such as competitive target binding and allosteric modulation can be harnessed to develop responsive materials with applications in tissue engineering and drug delivery.

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Identification of thaumatin‐like protein and aspartyl protease as new major allergens in lettuce (Lactuca sativa)
Authors: Muñoz‐García Esther , Luengo‐Sánchez Olga , Haroun‐Díaz Elisa , Maroto Aroa Sanz , Palacín Arancha , Díaz –Perales Araceli , de las Heras Gozalo Manuel , Labrador‐Horrillo Moisés , Vivanco Fernando , Cuesta‐Herranz Javier , Pastor‐Vargas Carlos
Published: August 2013

Scope

Today, about 2–8% of the population of Western countries exhibits some type of food allergy whose impact ranges from localized symptoms confined to the oral mucosa to severe anaphylactic reactions. Consumed worldwide, lettuce is a Compositae family vegetable that can elicit allergic reactions. To date, however, only one lipid transfer protein has been described in allergic reaction to lettuce. The aim of this study was to identify potential new allergens involved in lettuce allergy.

Methods and results

Sera from 42 Spanish lettuce‐allergic patients were obtained from patients recruited at the outpatient clinic. IgE‐binding proteins were detected by SDS‐PAGE and immunoblotting. Molecular characterization of IgE‐binding bands was performed by MS. Thaumatin was purified using the Agilent 3100 OFFGEL system. The IgE‐binding bands recognized in the sera of more than 50% of patients were identified as lipid transfer protein (9 kDa), a thaumatin‐like protein (26 kDa), and an aspartyl protease (35 and 45 kDa). ELISA inhibition studies were performed to confirm the IgE reactivity of the purified allergen.

Conclusion

Two new major lettuce allergens—a thaumatin‐like protein and an aspartyl protease—have been identified and characterized. These allergens may be used to improve both diagnosis and treatment of lettuce‐allergic patients.
G‐shaped monopole antenna with dual band‐stop function for UWB communications
Authors: Ojaroudi Nasser , Ojaroudi Mohammad
Published: August 2013

In this study, a new design of dual band‐notched monopole antenna for UWB systems has been presented. The antenna consists of a G‐shaped radiating patch with a rotated Γ‐shaped slot, a feed line, and a ground plane with an inverted fork‐shaped slit which provides a wide usable fractional bandwidth of more than 125% with double band‐stop performance. By applying the inverted fork‐shaped slit in the ground plane, a new resonance at higher frequency range (11.5 GHz) is excited and much wider impedance bandwidth can be produced. In the proposed monopole antenna, to generate a single frequency band‐stop performance we convert a square radiating patch to G‐shaped structure and also by cutting a rotated Γ‐shaped slot, dual band‐notched function can be achieved. Simulated and measured results obtained for this antenna show that the proposed antenna offers very wide bandwidth from 2.7 to 12.3 GHz with two notched bands covering all the 5.2/5.8 GHz WLAN, 3.5/5.5 GHz WiMAX, and 4‐GHz C‐bands. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2686–2689, 2013
A low power triple‐mode parallel‐processing CMOS receiver for BD‐II/GPS/Galileo joint navigation applications
Authors: Zhongyuan Hou , Chuan Wang , Junhua Liu , Huailin Liao , Xing Zhang
Published: August 2013

This article presents a low power triple‐mode parallel‐processing CMOS receiver for BD‐II/GPS/Galileo joint navigation applications. An innovative image rejecting parallel‐processing architecture is proposed, which utilizes a single frequency synthesizer, shares the front‐end, and adopts two complex band‐pass filters in two channels separately, aiming for the receiving of BD‐II B1/GPS L1/GALILEO L1 multistandard navigation signals simultaneously. The proposed triple‐mode parallel‐processing receiver is fabricated in a 0.18 μm CMOS process with 22.2 mA power consumption under the triple‐mode parallel‐processing navigation. Measured results show that it has a maximum conversion gain of 101.5 dB and a double‐side‐band noise figure of 3.3 dB with the fixed IF of 7*f0 (f0 = 1.023 MHz), tunable IF bandwidth of 2*f0/4*f0, and more than 34 dB image rejection. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2616–2620, 2013
Analysis of tem three‐section symmetrical directional couplers with tandem‐connected center section
Authors: Wincza Krzysztof , Gruszczynski Slawomir
Published: August 2013

The analysis of TEM three‐section symmetrical directional couplers with tightly coupled section realized as a tandem connection of two coupled‐line sections has been shown. The design equations allowing for calculating the required even‐mode characteristic impedances of coupled‐line sections for arbitrarily chosen coupling coefficient and coupling ripple have been derived. The proposed method has been utilized for analysis of three‐section 3‐dB symmetrical couplers with different coupling ripple and the results are given in a tabular form. The theoretical analysis has been confirmed by measurements of a 3‐dB three‐section symmetrical coupler, in which coupled‐line sections constituting a tightly coupled section have been miniaturized to for better fitting to the coupler's structure. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2578–2582, 2013
WDM PON purpose remote pumped bidirectional EDFA using cascading FBGS as a pump reflector
Authors: Yu Yi Lin , Liaw Shien‐Kuei , Liu Ren‐Yang , Shin Chow Shing
Published: August 2013

We proposed a remote pumped bidirectional C+L band fiber amplifier for wavelength division multiplexing passive optical network. A high‐reflectivity pump reflector using three cascading fiber Bragg gratings is designed to reflect the residual pump power for L‐band amplification. Both the gains for C‐band and L‐band are larger than 10.0 dB under −10 dBm launched power. Using the remote pumped bidirectional fiber amplifier, the power penalty is only 0.82 dB after 10 Gb/s, 24 km bidirectional transmission. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2553–2556, 2013
Compact wideband bandstop filters with electrically coupled open stubs
Authors: Lee Hyun‐Seung , Lim Won‐Gyu , Kim Choul‐Young
Published: August 2013

In this article, a compact wideband bandstop filter in the form of open stub combination is proposed. The wideband characteristic of the proposed bandstop filter is due to electrical coupling at the ends of the two open stubs. A stopband is approximately improved by 52% (rejection depth: −20 dB) compared with the case that the end of open stub is uncombined. Proposed structure increases the skirt selectivity and elastically controls the frequency bandwidth and rejection depth. Furthermore, stopband is extended about 125% (rejection depth: −20 dB), when spurline is added to the proposed bandstop filter without any size increment. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2701–2703, 2013
A feed‐forward equalizer with winner‐take‐all variable gain amplifiers for backplane channels
Authors: Arigong Bayaner , Zhang Hualiang , Jung Sungyong , Kim Hyoungsoo
Published: August 2013

In this article, a transversal filter with winner‐take‐all variable gain amplifiers is investigated to improve the performance of a feed‐forward equalizer. The proposed equalizer structure with nine gain cells has wide bandwidth and improved voltage headroom, at the same time achieving the low power consumption per gain cell. The proposed equalizer is fabricated in a 0.18 μm CMOS process and shows the successful compensation with 30 and 60 in backplanes with 3 Gbps signal. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2666–2670, 2013
Reduction of mutual coupling between E‐shaped microstrip antennas by using a simple microstrip I‐section
Authors: Ghosh Chandan Kumar , Parui Susanta Kumar
Published: August 2013

Mutual coupling is an inevitable phenomenon in multielement antenna systems. It can significantly degrade the performance of array systems. A number of works have been done on the suppression of mutual coupling in the recent years. In this article, we propose a simple I‐shaped resonator in between two E‐shaped microstrip antenna elements separated by 0.45λ to reduce the mutual coupling in patch array of antennas. The mutual coupling has been reduced by more than 30 dB by the introduction of this simple I‐shaped resonator on the same plane of the microstrip radiator. We have developed an experimental model that has proven this concept of antenna coupling reduction. Finally, the influence of other antenna parameters on the mutual coupling level has been studied. One may find its application in wireless communication. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2544–2549, 2013
A novel dual‐band bandpass filter using CRLH triangle mushroom structure and DGS
Authors: Cao Xin , Tang Zongxi , Wang Fei , Wu Yunqiu , Zhang Biao
Published: August 2013

In this article, a novel dual‐band bandpass filter using composite right/left handed (CRLH) triangle mushroom structure and defected ground structure (DGS) is proposed. The proposed filter uses triangle mushroom structure as the CRLH transmission line to achieve low‐in‐band insertion loss and compact size, and DGS to achieve out‐band rejection. Simulation and measurement results are in good agreement and the good properties mentioned above have been verified. It is proved that CRLH triangle mushroom structure and DGS can be both used to reduce the size of the filter and increase the rejection between the passbands in multipassband filter applications for the first time. This new combination of the two different structures has succeeded in achieving excellent performance. This novel filter can be applied in the microwave circuits and wireless communication systems. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2756–2759, 2013
Increased lipid oxidation during exercise in obese pubertal girls: A QUALITY study
Authors: Jabbour Georges , O'Loughlin Jennifer , Sabiston Catherine , Tremblay Angelo , Mathieu Marie‐Eve
Published: August 2013

Objective

This study explores differences in LO rates between pre‐pubertal and pubertal girls of three body weight status groups.

Methods

The sample included 39 pre‐pubertal girls [12 normal‐weight (NW), 12 overweight (OW), and 15 obese (OB)] and 37 pubertal girls [16 NW, 10 OW, and 11 OB]. Following a rest period, the girls performed a graded maximal cycling test. The %LO contribution was computed at each stage.

Results

The %LO contribution did not differ between NW, OW, or OB pre‐pubertal girls at each exercise stage. In contrast, pubertal OB girls showed a statistically significantly higher %LO contribution at 25, 50, and 75 W stages compared with OW and NW as well as with OB pre‐pubertal girls.

Conclusions

Our results demonstrate that entering puberty is a period associated with differentiation in substrate selection in obese girls. A higher %LO contribution may help girls to solicit more fat while performing submaximal exercise.
Improving children's obesity‐related health care quality: Process outcomes of a cluster‐randomized controlled trial
Authors: Taveras Elsie M. , Marshall Richard , Horan Christine M. , Gillman Matthew W. , Hacker Karen , Kleinman Ken P. , Koziol Renata , Price Sarah , Rifas‐Shiman Sheryl L. , Simon Steven R.
Published: August 2013

Objective

To examine the extent to which an intervention using electronic decision support delivered to pediatricians at the point‐of‐care of obese children, with or without direct‐to‐parent outreach, improved health care quality measures for child obesity.

Design and Methods

Process outcomes from a three‐arm, cluster‐randomized trial from 14 pediatric practices in Massachusetts were reported. Participants were 549 children aged 6‐12 years with body mass index (BMI) ≥ 95th percentile. In five practices (Intervention‐1), pediatricians receive electronic decision support at the point‐of‐care. In five other practices (Intervention‐2), pediatricians receive point‐of‐care decision support and parents receive information about their child's prior BMI before their scheduled visit. Four practices receive usual care. The main outcomes were Healthcare Effectiveness Data and Information Set (HEDIS) performance measures for child obesity: documentation of BMI percentile and use of counseling codes for nutrition or physical activity.

Results

Compared to the usual care condition, participants in Intervention‐2, but not Intervention‐1, had substantially higher odds of use of HEDIS codes for BMI percentile documentation (adjusted OR: 3.97; 95% CI: 1.92, 8.23) and higher prevalence of use of HEDIS codes for counseling for nutrition or physical activity (adjusted predicted prevalence 20.3% [95% CI 8.5, 41.2] for Intervention −2 vs. 0.0% [0.0, 2.0] for usual care).

Conclusion

An intervention that included both decision support for clinicians and outreach to parents resulted in improved health care quality measures for child obesity.
Formation of truncated peptide by‐products via sequence‐specific formyl group transfer from Trp(For) residues to Nα in the course of Boc‐SPPS
Authors: Azev Viatcheslav N. , Mustaeva Leila G. , Gorbunova Elena Yu. , Molchanov Maksim V. , Rodionov Igor L.
Published: August 2013

(NIn)‐Formyl protective group of tryptophan has been introduced as a base/nucleophile‐labile protective group. It has long been known that a free Nα‐amino group of the peptide can serve as a nucleophile: an irreversible formyl NIn → NH2 transfer is consistently observed when deformylation is performed last on an otherwise deprotected peptide that possesses free Nα‐amino group. Obviously, this particular side reaction should be expected any time free amino group is exposed to Trp(For), but, at the best of our knowledge, has never been reported in the course of Boc‐SPPS. In the present communication, we describe a set of appropriately designed model experiments that permitted to detect the title side reaction both in solution and in solid‐phase reactions. We observed intermolecular formyl group transfer with a model compound, Trp(For)‐NH2. Importantly, we also observed this migration on solid support with the rate roughly estimated to be up to 1% of residues per minute. We also observed that the formyl‐group transfer reaction occurred in a sequence‐dependent manner and was suppressed to a non‐detectable level using ‘in situ neutralization’ technique. Because this side reaction is sequence dependent, there might be situations when the rate of the formation of Nα‐formyl termination by‐products is significant. In other cases, the Nα‐For truncated by‐products would not contaminate the final peptide significantly but still could be a source of microheterogeneity. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd.
Terahertz studies of carrier localization in spontaneously forming polar lateral heterostructures
Authors: Metcalfe Grace D. , Hirai Asako , Young Erin C. , Speck James S. , Shen Hongen , Wraback Michael
Published: August 2013

We employ near‐bandgap terahertz emission spectroscopy to study lateral heterostructures resulting from basal plane stacking faults in m ‐plane GaN. The predominant stacking faults have I1 character and behave as an array of spontaneously forming layers comprised of a single cubic stacking sequence within the wurtzite matrix that terminate the spontaneous polarization along the in‐plane c‐axis, leading to strong lateral electric fields. Spectral tuning of femtosecond excitation pulses enables observation of the transition from carrier transport in the continuum to formation of instantaneous dipoles and nonlinear susceptibility associated with both the quantum‐well‐like regions of the cubic layers and polarization‐induced triangular‐like potentials. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Propagation of dilatation and shear waves through a dynamic checkerboard material geometry in 1D space + time
Authors: Sanguinet W.C. , Lurie K.A.
Published: August 2013

We study the propagation of dilatational and shear waves through an isotropic elastic material having the dilatation and shear moduli variable in space and time. Two isotropic materials alternate occupying rectangular cells in 1D space + time producing a double periodic checkerboard material assembly. The materials are assumed to differ in their wave velocities (dilatational and shear) and to have pairwise equal values of wave impedances for each type of wave. We show, however, that, for both types of waves traveling normally to spatial interfaces between the materials, the average velocity of propagation is the same for certain ranges of material and structural parameters. Also, the energy is accumulated in those waves, and such accumulation occurs in very narrow pulses. This is unlike the wave propagation in a uniform static material, where both types of waves propagate at different speeds. The coincidence of average speeds of propagation appears to be due to the checkerboard material geometry. It creates the “plateau effect” within the ranges of material and structural parameters mentioned above [3, 4, 6]. These ranges do not include the purely uniform material. In elastodynamics, the concept of dynamic materials has been previously studied in references [2, 7].
Force‐based derivation of exact stiffness matrix for beams onWinkler‐Pasternak foundation
Authors: Limkatanyu Suchart , Damrongwiriyanupap Nattapong , Kwon Minho , Ponbunyanon Paitoon
Published: August 2013

In this paper, the exact element stiffness matrix for a beam on Winkler‐Pasternak foundation and the fixed‐end force vector due to a linearly distributed load are alternatively derived based on the virtual force principle. The exact element flexibility matrix is at the core of the derivation of the exact element stiffness matrix and is formulated based on the exact force interpolation functions. The virtual force principle is employed to reveal the governing differential compatibility equations as well as the associated end‐boundary compatibility conditions. The exact force interpolation functions of the beam‐foundation system are derived based on the analytical solution of the governing differential compatibility equations of the problem for all combinations of foundation parameters and beam rigidity. This feature is unique to this paper. The matrix virtual force equation is employed to obtain the exact element flexibility matrix using the exact force interpolation functions. The so‐called “natural” element stiffness matrix is obtained by inverting the exact element flexibility matrix. Three numerical examples confirm the accuracy and the efficiency of the natural beam element on Winkler‐Pasternak foundation and show the deficiency of the widely used Winkler foundation model.
Micro‐poromechanics model of fluid‐saturated chemically active fibrous media
Authors: Misra Anil , Parthasarathy Ranganathan , Singh Viraj , Spencer Paulette
Published: August 2013

We have developed a micromechanics based model for chemically active saturated fibrous media that incorporates fiber network microstructure, chemical potential driven fluid flow, and micro‐poromechanics. The stress‐strain relationship of the dry fibrous media is first obtained by considering the fiber behavior. The constitutive relationships applicable to saturated media are then derived in the poromechanics framework using Hill's volume averaging. The advantage of this approach is that the resultant continuum model accounts for the discrete nature of the individual fibers while retaining a form suitable for porous materials. As a result, the model is able to predict the influence of micro‐scale phenomena, such as the fiber pre‐strain caused by osmotic effects and evolution of fiber network structure with loading, on the overall behavior and in particular, on the poromechanics parameters. Additionally, the model can describe fluid‐flow related rate‐dependent behavior under confined and unconfined conditions and varying chemical environments. The significance of the approach is demonstrated by simulating unconfined drained monotonic uniaxial compression under different surrounding fluid bath molarity, and fluid‐flow related creep and relaxation at different loading‐levels and different surrounding fluid bath molarity. The model predictions conform to the experimental observations for saturated soft fibrous materials. The method can potentially be extended to other porous materials such as bone, clays, foams and concrete.
Enzyme replacement therapy on hypophosphatasia mouse model
Authors: Oikawa Hirotaka , Tomatsu Shunji , Haupt Bisong , Montaño Adriana M. , Shimada Tsutomu , Sly William S.
Published: August 2013

Hypophosphatasia (HPP) is an inborn error of metabolism caused by deficiency of the tissue‐nonspecific alkaline phosphatase (TNSALP), resulting in a defect of bone mineralization. Natural substrates for this ectoenzyme accumulate extracellulary including inorganic pyrophosphate (PPi), an inhibitor of mineralization, and pyridoxal 5‐phosphate (PLP), a co‐factor form of vitamin B6. Enzyme replacement therapy (ERT) for HPP by functional TNSALP is one of the therapeutic options. The C‐terminal‐anchorless human recombinant TNSALP derived from Chinese hamster ovary cell lines was purified. TNSALP‐null mice (Akp2‐/‐), an infantile model of HPP, were treated from birth using TNSALP and vitamin B6 diet. Long‐term efficacy studies of ERT consisted of every 3 days subcutaneous or intravenous injections till 28 days old (dose 20 U/g) and subsequently every 3 days intravenous injections for 6 months (dose 10 U/g). We assessed therapeutic effect by growth and survival rates, fertility, skeletal manifestations, and radiographic and pathological finding. Treated Akp2‐/‐ mice grew normally till 4 weeks and appeared well with a minimum skeletal abnormality as well as absence of epilepsy, compared with untreated mice which died by 3 weeks old. The prognosis of TNSALP‐treated Akp2‐/‐ mice was improved substantially: 1) prolonged life span over 6 months, 2) improvement of the growth, and 3) normal fertility. After 6 months of treatment, we found moderate hypomineralization with abnormal proliferative chondrocytes in growth plate and articular cartilage. In conclusion, ERT with human native TNSALP improves substantial clinical manifestations in Akp2‐/‐ mice, suggesting that ERT with anchorless TNSALP is also a potential therapy for HPP.
Maritime safety and the ISM code: a study of investigated casualties and incidents
Authors: Batalden Bjørn-Morten , Sydnes Are Kristoffer
Published: August 2013

In 1993, the International Maritime Organization adopted the International Safety Management (ISM) Code which requires all shipping companies operating certain types of vessels to establish safety management systems. Nevertheless, two decades later, maritime safety remains a concern. This article studies 94 maritime cases investigated by the Maritime Accident Investigation Branch in the UK. By providing an analysis of reported casualties and incidents, it highlights current challenges in maritime safety. For each casualty and incident, the study reviews the underlying causal factors. These causal factors are then coded according to the functional sections of the ISM Code, covering various aspects of safety management. To investigate human and organizational factors involved in the casualties and incidents, the human factor analysis and classification system (HFACS) is applied to code the same data. Finally, the relative seriousness of casualties and incidents is considered to discuss the findings from ISM Code and HFACS reviews. The study found that the main challenges pertain to the development of plans for shipboard operations, local shipboard management, and the ability of the company to verify when such practices deviate from best practices or required standards.
What makes a joint venture: Micro‐evidence from Sino‐Italian contracts
Authors: Gattai Valeria , Natale Piergiovanna
Published: August 2013

This paper provides new contract‐level evidence on control rights allocation in order to define what makes a joint venture. Property rights theory of the firm identifies circumstances under which joint control alleviates investment distortions due to contract incompleteness. We compare predictions of the theoretical literature with actual governance structures of Sino‐Italian joint ventures, as reported in a questionnaire submitted to the entire population of Italian enterprises operating in China. With an exceptional response rate of 60%, our evidence confirms most of the theoretical predictions and helps select among competing approaches to model joint ventures.
Decompression mineral microtextures in granulites of the Irkut block (Sharyzhalgai uplift of the Siberian Platform)
Authors: Sukhorukov V.P.
Published: August 2013

This paper presents mineral reactions in metapelites and estimations of PT-conditions of metamorphism for paragranulites of the Irkut block of the Sharyzhalgay uplift (Siberian Platform). The geothermometeric data based on exchange reactions, the contents of Na in cordierite and Ti in zircon indicate that the peak temperature of metamorphism reached ca. 800 °C at 6–7 kbar. The observed mineral reactions suggest that the pressure decreased to ca. 3 kbar at a retrograde stage of metamorphism.
Conditions of the accumulation of organic matter and metals in the bottom sediments of the Chukchi Sea
Authors: Astakhov A.S. , Gusev E.A. , Kolesnik A.N. , Shakirov R.B.
Published: August 2013

The chemical composition of bottom sediments in the Chukchi and, partly, East Siberian Seas was studied. In the south and west of the Chukchi Sea, a zone has been detected with the accumulation of sediments rich in organic carbon, an increased background content and anomalies of sulfophile metals (Mo, Zn, Hg, Ag, Au), iron-group metals (V, Ni, Co), and some PGE (Ru, Pt). This zone is confined to the neotectonic active system of rift troughs extending from the Bering Strait and eastern Chukchi Peninsula to the continental slope, where it is bounded by the Cenozoic Charlie rift basin of the Canadian hollow. The geochemical features of the carbon-enriched sediments evidence that they formed under oxygen-deficient conditions and, sometimes, in suboxic and anoxic environments near endogenic water and gas sources. The high carbon and metal contents suggest that the very fine-grained sediments in the rift troughs of the Chukchi Sea are a possible analog of some types of ancient highly carbonaceous sediments belonging to black shales.
Peer attachment formation by systemic redox regulation with social training after a sensitive period
Authors: Koshiba Mamiko , Karino Genta , Senoo Aya , Mimura Koki , Shirakawa Yuka , Fukushima Yuta , Obara Saya , Sekihara Hitomi , Ozawa Shimpei , Ikegami Kentaro , Ueda Toyotoshi , Yamanouchi Hideo , Nakamura Shun
Published: August 2013

Attachment formation is the most pivotal factor for humans and animals in the growth and development of social relationships. However, the developmental processes of attachment formation mediated by sensory-motor, emotional and cognitive integration remain obscure. Here we developed an animal model to understand the types of social interactions that lead to peer-social attachment formation. We found that the social interaction in a sensitive period was essential to stabilise or overwrite the initially imprinted peer affiliation state and that synchronised behaviour with others based on common motivations could be a driver of peer social attachment formation. Furthermore, feeding experience with supplementation of ubiquinol conferred peer social attachment formation even after the sensitive period. Surprisingly, the experience of feeding beyond the cage window was also effective to reduce the required amount ubiquinol, suggesting that peri-personal space modulation may affect socio-emotional cognition and there by lead to attachment formation.
Bubble formation during the collision of a sessile drop with a meniscus
Authors: Keij D. L. , Winkels K. G. , Castelijns H. , Riepen M. , Snoeijer J. H.
Published: August 2013

The impact of a sessile droplet with a moving meniscus, as encountered in processes such as dip-coating, generically leads to the entrapment of small air bubbles. Here we experimentally study this process of bubble formation by looking through the liquid using high-speed imaging. Our central finding is that the size of the entrapped bubble crucially depends on the location where coalescence between the drop and the moving meniscus is initiated: (i) at a finite height above the substrate, or (ii) exactly at the contact line. In the first case, we typically find bubble sizes of the order of a few μm, independent of the size and speed of the impacting drop. By contrast, the bubbles that are formed when coalescence starts at the contact line become increasingly large, as the size or the velocity of the impacting drop is increased. We show how these observations can be explained from a balance between the lubrication pressure in the air layer and the capillary pressure of the drop.
On the regularity for the Boussinesq equations in a bounded domain
Authors: Hu Weiwei , Kukavica Igor , Ziane Mohammed
Published: August 2013

We address the regularity for the 2D Boussinesq equations with zero diffusivity and positive viscosity on an open bounded smooth domain Ω. In particular, we prove that for the initial velocity in H2(Ω) and the initial density in H1(Ω) there exists a global in time solution for which the velocity and the density are locally in time bounded functions in H2 and H1, respectively.
Note: A portable magnetic field for powering nanomotors, microswimmers, and sensors
Authors: Kinnunen P. , McNaughton B. H. , Niinimäki J.
Published: August 2013

Time-varying magnetic fields are the basis of many modern devices and are used to remotely power and steer nanomotors and microswimmers. However, the required magnetic field setups are often prohibitively bulky laboratory setups that require technical expertise to build, modify, or relocate. Here we introduce a programmable magnetic field setup based on consumer electronics that is both portable and easy to use. The complete setup consists of a laptop computer, an audio amplifier, and audio inductors and was used to create complex magnetic fields in 0.5–2000 Hz frequency range with up to 4.7 mT amplitude. The setup was also validated using an example application, namely a rotating magnetic field with a constant amplitude and fixed frequency, which has applications in powering nanosensors and microswimmers.
Field-pulse memory in a spin-glass
Authors: Schmitt Devin C. , Prestigiacomo Joseph C. , Adams Philip W. , Young David P. , Stadler Shane , Chan Julia Y.
Published: August 2013

We report a magnetic field-pulse memory effect in the temperature-dependent magnetization of Tb30Ru6.0Sn29.5, a spin-glass material having a newly identified structure type. Tb30Ru6.0Sn29.5 exhibits a glassy magnetization component of ∼2290 emu/mol-Tb, which represents over 84% of its total saturation magnetization. We show that when a magnetic field pulse of a few hundred gauss is applied to the sample as it is cooling, the system retains a memory of the temperature at which the pulse was applied. Upon warming, the imprinted memory is observed as a precipitous drop in magnetization at the pulse temperature.
Upscaling Lévy motions in porous media with long range correlations
Authors: Park Moongyu
Published: August 2013

Bacterial motility has been modeled by Lévy motions which were upscaled in porous media, with drift processes such as Lévy processes and time-changed Brownian motion, via central limit theorems. It was possible to prove the limit theorems and upscale the processes because of the independence of their increments. Therefore, it has not been applied to processes with correlated increments such as fractional Brownian motions. In this paper, the upscaling approach is generalized to porous media with long-range correlated processes. The processes are modeled by a fractional Brownian velocity process and p-diffusive position processes that were defined and used to classify diffusion processes by O’Malley and Cushman [“A renormalization group classification of nonstationary and/or infinite second moment diffusive processes,” J. Stat. Phys. 146, 989–1000 (2012)]10.1007/s10955-012-0448-3. A few examples of p-diffusive processes are discussed by computing the values of the parameter p.
Influence of the repulsive Coulomb barrier on photoelectron spectra and angular distributions in a resonantly excited dianion
Authors: Horke Daniel A. , Chatterley Adam S. , Verlet Jan R. R.
Published: August 2013

A photoelectron imaging study of the gas-phase dianion of pyrromethene-556 is presented. The photoelectron spectra and angular distributions following resonant excitation of the S1 excited state with nanosecond and femtosecond laser pulses are compared, and the influence of the repulsive Coulomb barrier (RCB) in both cases evaluated. Photoelectron angular distributions show the effect of molecular alignment due to an allowed electronic excitation and can be understood qualitatively based on the calculated RCB surface using the Local Static Approximation. Comparison between femtosecond and nanosecond excitation reveals marked differences in the photoelectron spectra. While femtosecond experiments confirm that tunneling through the RCB is adiabatic, nanosecond experiments show a broad photoelectron feature peaking near the RCB maximum. This is explained in terms of the lifetime of internal conversion, which has been determined by time-resolved photoelectron spectroscopy to be ∼120 ps: as this is faster than the nanosecond laser pulses, multiple photons can be absorbed through the S1 ← S0 transition which leads to large amounts of internal energy and enables electron detachment directly above the RCB. Fragmentation and detachment from the monoanion are also inferred by the presence of photoelectrons emitted at very low kinetic energy. Our results highlight the difficulty in interpreting photoelectron spectra of polyanions in which a resonant state is excited.
Low-frequency unsteadiness in the vortex formation region of a circular cylinder
Authors: Lehmkuhl O. , Rodríguez I. , Borrell R. , Oliva A.
Published: August 2013

The presence of low-frequency fluctuations in the wake of bluff bodies have been observed in several investigations. Even though the flow past a circular cylinder at Re = 3900 (Re = UrefD/ν) has been the object of several experimental and numerical investigations, there is a large scattering in the average statistics in the near wake. In the present work, the flow dynamics of the near wake region behind a circular cylinder has been investigated by means of direct numerical simulations and statistics have been computed for more than 858 shedding cycles. The analysis of instantaneous velocity signals of several probes located in the vortex formation region, point out the existence of a low-frequency fluctuation at the non-dimensional frequency of fm = 0.0064. This large-scale almost periodic motion seems to be related with the modulation of the recirculation bubble which causes its shrinking and enlargement over the time. Two different configurations have been identified: (i) a high-energy mode with larger fluctuations in the shear-layer and in the vortex formation region (Mode H) and (ii) a low-energy mode with weaker fluctuations in the shear layer (Mode L). The influence of such a low-frequency in the wake topology has been studied not only by means of the phase-average flow field for each mode, but also by the analysis of the time-average first- and second-order statistics of each wake mode. The results are compared with the long-term averaged solution and with results in the existing literature.
Nonlinear optical response in solids from time-dependent density-functional theory simulations
Authors: Goncharov Vladimir A.
Published: August 2013

A new method for computing nonlinear susceptibilities of periodic solids is presented. The electronic response and polarization current are obtained from time-dependent Schrödinger equation dynamically coupled to the external electromagnetic field. Solid's polarization resulting from quasi-monochromatic excitation is examined in frequency domain. The higher order susceptibilities are calculated non-perturbatively. The method is illustrated by examples of third harmonic generation in silicon and carbon diamond.
Independent phasing of rephasing and non-rephasing 2D electronic spectra
Authors: Singh V. P. , Fidler A. F. , Rolczynski B. S. , Engel G. S.
Published: August 2013

Assigning absolute phase to two-dimensional (2D) third-order nonlinear optical signals generally requires acquiring both the rephasing and the non-rephasing signals and comparing the sum of the two to spectrally resolved pump-probe spectra. To date, however, Gradient Assisted Photon Echo Spectroscopy (GRAPES) has only been able to acquire rephasing spectra. Such a constraint requires a new phasing protocol. Here, we analytically prove that the rephasing and non-rephasing spectra can be phased independently using pump-probe signal. We verify this result holds even for finite duration pulses by simulation. This relationship holds for all 2D spectroscopies, not only GRAPES. In addition, we present improvements to GRAPES that enable acquisition of rephasing and non-rephasing signals in different phase-matched directions. We employ our phasing protocol to phase the data for laser dye IR-144, leading to reconstruction of purely absorptive 2D spectrum.