bluuebunny/crossref_metadata_2025 huggingface dataset:
Acoustic losses in a thick quartz plate at low temperatures
Authors: Grib A. , Heinert D. , Nawrodt R. , Schwarz C. , Große V. , Seidel P. , Martin I. , Rowan S. , Hough J.
Published: January 2010

We have shown that thermoelastic losses give the significant contribution to the total mechanical damping in the low loss quartz even for the bulk samples if the thickness of the sample is smaller than other dimensions. We have developed a model that describes experimental data of mechanical losses in a round quartz plate with the diameter 7.48 cm and the thickness 1.2 cm at temperatures 5–25 K in the range of eigenfrequencies 11–300 kHz. The model takes into account both the contribution of thermoelastic losses and the contribution due to the interaction of the acoustic wave with thermal phonons (Akhieser damping). Thermoelastic processes determine losses below 120 kHz. At larger eigenfrequencies, the Akhieser damping dominates.
A Lagrangian approach to identifying vortex pinch-off
Authors: O’Farrell Clara , Dabiri John O.
Published: January 2010

A criterion for identifying vortex ring pinch-off based on the Lagrangian coherent structures (LCSs) in the flow is proposed and demonstrated for a piston-cylinder arrangement with a piston stroke to diameter (L/D) ratio of ≈12. It is found that the appearance of a new disconnected LCS and the termination of the original LCS are indicative of the initiation of vortex pinch-off. The subsequent growth of new LCSs, which tend to roll into spirals, indicates the formation of new vortex cores in the trailing shear layer. Using this criterion, the formation number is found to be 4.1±0.1, which is consistent with the predicted formation number of ≈4 of Gharib et al. [Gharib et al. J. Fluid Mech. 360, 121 (1998)]. The results obtained using the proposed LCS criterion are compared with those obtained using the circulation criterion of Gharib et al. and are found to be in excellent agreement. The LCS approach is also compared against other metrics, both Lagrangian and Eulerian, and is found to yield insight into the pinch-off process that these do not. Furthermore, the LCS analysis reveals a consistent pattern of coalescing or “pairing” of adjacent vortices in the trailing shear layer, a process which has been extensively documented in circular jets. Given that LCSs are objective and insensitive to local errors in the velocity field, the proposed criterion has the potential to be a robust tool for pinch-off identification. In particular, it may prove useful in the study of unsteady and low Reynolds number flows, where conventional methods based on vorticity prove difficult to use.
Diameter dependent performance of high-speed, low-power InAs nanowire field-effect transistors
Authors: Khayer M. Abul , Lake Roger K.
Published: January 2010

The diameter dependent performance metrics of InAs nanowire (NW) field-effect transistors (FETs) are investigated using an analytical two-band model and a semiclassical ballistic transport model. The first analysis of the diameter dependence of the current, the gate delay time, the power-delay product, and the energy-delay product of InAs NW FETs, which operate in the quantum capacitance limit (QCL), are presented. Because of its small density of states, which results from the lower electron effective mass, relatively large diameter (⩽60nm) InAs NW FETs operate in the QCL. Both the energy-delay and power-delay products are reduced as the diameter is reduced, and optimum designs are obtained for diameters in the range 10–40nm. Power-delay product varies from 2×10−20to63×10−20J for all devices with a source Fermi level range 0.1–0.2eV. The gate delay time for all devices varies from 4to16fs and decreases as the NW diameter increases. Analytical expressions are derived for the key device metrics for a single-moded device and compared with the numerical results. The NW FETs provide both ultralow-power switching and high speed.
Design of multibeam scanning antennas with high gains and low sidelobes using gradient-index metamaterials
Authors: Ma Hui Feng , Chen Xi , Yang Xin Mi , Jiang Wei Xiang , Cui Tie Jun
Published: January 2010

Metamaterials, composed of artificial structures with subwavelength unit cells, can be fabricated to achieve gradually refractive indices. By designing the refractive indices properly, a gradient-index planar slab will transform spherical waves to plane waves. Using such a property, we propose a beam-scanning antenna with high gain and low sidelobes based on the gradient-index planar lens and a horn antenna, where the beam direction is controlled by the refractive-index distribution. When such four lenses are fixed together, we can get a four-beam scanning antenna with high gain and low sidelobes, in which each beam can be controlled independently. The gradient-index planar lenses can be realized using metamaterial structures.
Interfacial instability induced by lateral vapor pressure fluctuation in bounded thin liquid-vapor layers
Authors: Kanatani Kentaro
Published: January 2010

We study an instability of thin liquid-vapor layers bounded by rigid parallel walls from both below and above. In this system, the interfacial instability is induced by lateral vapor pressure fluctuation, which is in turn attributed to the effect of phase change: evaporation occurs at a hotter portion of the interface and condensation at a colder one. The high vapor pressure pushes the interface downward and the low one pulls it upward. A set of equations describing the temporal evolution of the interface of the liquid-vapor layers is derived by applying long-wave approximation to both layers. This model neglects the effect of mass loss or gain at the interface and guarantees the mass conservation of the liquid layer. The result of linear stability analysis of the model shows that the presence of the pressure dependence of the local saturation temperature mitigates the growth of long-wave disturbances. The thinner vapor layer enhances the vapor pressure effect. We find the stability criterion, which suggests that only slight temperature gradients are sufficient to overcome the gravitational effect for a water/vapor system. The same holds for the Rayleigh–Taylor unstable case, with a possibility that the vapor pressure effect may be weakened if the accommodation coefficient is below a certain critical value.
Magnetic properties of graded A1/L1 films obtained by heat treatment of FePt/CoPt multilayers
Authors: Alexandrakis V. , Niarchos D. , Mergia K. , Lee Jehyun , Fidler J. , Panagiotopoulos I.
Published: January 2010

Structurally gradient layered A1/L10 films are obtained by heat treatment of magnetron sputter deposited FePt(20 nm)/CoPt(x nm) bilayers where x=0–120 nm. The magnetic properties can be tuned by adjustment of the layer thicknesses and taking advantage of the different heat-treatment temperatures required for the ordering of the L10 phase between FePt and CoPt.
Accurate extraction of Lagrangian coherent structures over finite domains with application to flight data analysis over Hong Kong International Airport
Authors: Tang Wenbo , Chan Pak Wai , Haller George
Published: January 2010

Locating Lagrangian coherent structures (LCS) for dynamical systems defined on a spatially limited domain present a challenge because trajectory integration must be stopped at the boundary for lack of further velocity data. This effectively turns the domain boundary into an attractor, introduces edge effects resulting in spurious ridges in the associated finite-time Lyapunov exponent (FTLE) field, and causes some of the real ridges of the FTLE field to be suppressed by strong spurious ridges. To address these issues, we develop a finite-domain FTLE method that renders LCS with an accuracy and fidelity that is suitable for automated feature detection. We show the application of this technique to the analysis of velocity data from aircraft landing at the Hong Kong International Airport.
Temperature-dependent modulation characteristics for 1.3 μm InAs/GaAs quantum dot lasers
Authors: Xu Peng-Fei , Yang Tao , Ji Hai-Ming , Cao Yu-Lian , Gu Yong-Xian , Liu Yu , Ma Wen-Quan , Wang Zhan-Guo
Published: January 2010

Temperature-dependent modulation characteristics of 1.3 μm InAs/GaAs quantum dot (QD) lasers under small signals have been carefully studied at various bias currents. Based on experimental observations, it is found that the modulation bandwidth significantly increases when excited state (ES) lasing emerges at high temperature. This is attributed to additional photons emitted by ES lasing which contribute to the modulation response. A rate equation model including two discrete electron energy levels and the level of wetting layer has been used to investigate the temperature-dependent dynamic behavior of the QD lasers. Numerical investigations confirm that the significant jump for the small signal modulation response is indeed caused by ES photons. Furthermore, we identify how the electron occupation probabilities of the two discrete energy levels can influence the photon density of different states and finally the modulation rate. Both experiments and numerical analysis show that the modulation bandwidth of QD lasers at high temperature can be increased by injecting more carriers into the ES that has larger electron state degeneracy and faster carrier’s relaxation time than the ground state.
Systematic variations in structural and electronic properties of BiFeO3 by A-site substitution
Authors: Zhang Zhen , Wu Ping , Chen Lang , Wang Junling
Published: January 2010

Systematic variations in the structural and electronic properties of BiFeO3 with A-site substitutions were studied using first-principles density functional theory calculations. It is found that the ferroelectric distortion of BiFeO3 with group IIIA element (Sc3+, Y3+, and La3+) substitutions is significantly affected by the hybridization between substitute d states and oxygen 2p states, while that with group VB element (Sb3+) substitution is stabilized by the s2 lone pair electrons. For both groups, the substitute with smaller ionic size and larger electronegativity causes more significant off-center displacement and narrower band gap.
Cage effect dynamics
Authors: Khudyakov Igor , Zharikov Anatoly A. , Burshtein Anatoly I.
Published: January 2010

The kinetics of recombination/dissociation of photogenerated radical pairs (RPs) is described with a generalized model (GM), which combines exponential models (EMs) and contact models (CMs) of cage effect dynamics. The main assumption of EM is the irreversible dissociation of RP as a first-order reaction. CM takes into account repetitive contacts of radicals in the pair or reversible diffusional separation of radicals. The present GM accounts for both the recombination of RP within the cage of outcome and their diffusional separation in a free space. GM predicts that a short initial time RP decay is described by EM, and RP kinetics at longer times of observation is described by CM. This theory successfully describes available experimental data. Solvent viscosity effect on the cage effect values is also analyzed.
Dependence of magnetic susceptibility on stress in textured polycrystalline Fe81.6Ga18.4 and Fe79.1Ga20.9 Galfenol alloys
Authors: Mahadevan A. , Evans P. G. , Dapino M. J.
Published: January 2010

Magnetization and magnetostriction measurements in constant tension and compression as a function of applied magnetic field are reported for ⟨100⟩ oriented, textured polycrystalline Fe81.6Ga18.4 and Fe79.1Ga20.9 Galfenol alloys. The susceptibility change with stress, or sensitivity, is maximum at zero field for both alloys. The greatest sensitivity is observed for the 18.4 at. % Ga alloy between −10 and +20 MPa, where domain wall motion dominates. The sensitivity is greater for the 20.9 at. % Ga alloy than for the 18.4 at. % Ga alloy below −15 MPa (domain rotation region). The difference in behavior is attributed to a difference in the anisotropy coefficient.
Correlation of energy band alignment and turn-on voltage in organic light emitting diodes
Authors: Wu I-Wen , Chen Yu-Hung , Wang Po-Sheng , Wang Chao-Gong , Hsu Shu-Han , Wu Chih-I
Published: January 2010

The correlation of energy alignment and turn-on voltage of organic light emitting diodes (OLEDs) was investigated. With identical hole transport layers (HTLs) and electron transport layers (ETLs), the turn-on voltages of OLEDs are always the same, regardless of the cathode structures, such as Ca, Al, LiF/Al, and Cs2CO3/Al. For devices with various combinations of HTLs and ETLs, the turn-on voltages are equal to the energy difference between the lowest unoccupied molecular orbital of ETLs and the highest occupied molecular orbital of HTLs, taking into consideration of vacuum level shift at organic interfaces measured from ultraviolet photoemission spectroscopy.
Micro-Raman spectroscopy of Si nanowires: Influence of diameter and temperature
Authors: Torres A. , Martín-Martín A. , Martínez O. , Prieto A. C. , Hortelano V. , Jiménez J. , Rodríguez A. , Sangrador J. , Rodríguez T.
Published: January 2010

Raman spectroscopy provides nondestructive information about nanoscaled semiconductors by modeling the phonon confinement effect. However, the Raman spectrum is also sensitive to the temperature, which can mix with the size effects borrowing the interpretation of the Raman spectrum. We present an analysis of the Raman spectra of Si nanowires (NWs). The influence of the excitation conditions and the temperature increase in the NWs are discussed. The interpretation of the data is supported by the calculation of the temperature inside the NWs with different diameters.
Temperature induced change in the hysteretic behavior of the capacitance-voltage characteristics of Pt–ZnO–Pb(Zr0.2Ti0.8)O3–Pt heterostructures
Authors: Pintilie L. , Dragoi C. , Radu R. , Costinoaia A. , Stancu V. , Pintilie I.
Published: January 2010

Pt – ZnO – Pb ( Zr 0.2 Ti 0.8 ) O 3 – Pt (PZT-ZnO) heterostructures were fabricated by using a sol-gel process. Capacitance-voltage measurements performed on a wide temperature range (20–450 K) have revealed the presence of a hysteresis that undergo a change of direction from clockwise at temperatures below 350 K to counter-clockwise at higher temperatures. In the first case, the hysteresis is produced by charge injection, similar to the case of classical metal-oxide-semiconductor capacitors. In the last case, the hysteresis is the fingerprint of polarization reversal, as reported for metal-ferroelectric-semiconductor (MFS) structures based on n-Si. The memory window at 450 K is about 6 V. This result suggests that PZT-ZnO MFS heterostructures can be used for memory devices working at elevated temperatures, in which the ZnO plays the role of the semiconductor.
The electronic structure of C60/ZnPc interface for organic photovoltaic device with blended layer architecture
Authors: Park S. H. , Jeong J. G. , Kim Hyo-Jin , Park Seung-Han , Cho Mann-Ho , Cho Sang Wan , Yi Yeonjin , Heo Min Young , Sohn Hyunchul
Published: January 2010

The interfacial electronic structures of fullerene (C60)/zinc-phthalocyanine (ZnPc) and C60/ZnPc:C60 (50 wt %) containing a blended layer were investigated by in situ ultraviolet photoelectron spectroscopy (UPS), in an attempt to understand the role of the blended layer in improving the performance of organic photovoltaic devices that contain such layers. From the UPS spectra, the band bending found to be 0.30 eV in the ZnPc layer and 0.43 eV in the C60 layer at the C60/ZnPc interface. On the other hand, the band bending was 0.25 eV in both of the organic layers at the ZnPc:C60/ZnPc interface and no significant band bending in the C60 layer at the C60/ZnPc:C60 interface was found. The observed interface dipole was 0.06 eV at the C60/ZnPc interface and 0.26 eV at the ZnPc:C60/ZnPc interface. The offset between the highest unoccupied molecular orbital of ZnPc and the lowest occupied molecular orbital of C60 was 0.75 eV at C60/ZnPc and was 1.04 eV at the ZnPc:C60/ZnPc interface. The increased offset can be attributed to an increase in the interface dipole, caused by the blending donor and acceptor material. The blending facilitates charge transfer between the donor and acceptor, resulting in an increase in the interface dipole, resulting in a larger offset.
Charge renormalization of nanoparticles immersed in a molecular electrolyte
Authors: Arenas-Gómez B. L. , González-Mozuelos P.
Published: January 2010

The renormalization of the electric charge of nanoparticles (small colloids) at infinite dilution immersed in a supporting electrolyte containing molecular ions is studied here using a simple model. The nanoparticles are represented by charged spheres of finite diameter, the anions are assumed to be pointlike, and the cations are modeled as two identical charged points connected by a rigid rod. The static structure of this model system is determined using the reference interaction site model equations with suitable closure relations and the renormalized charges are analyzed employing the dressed interactions site theory approach. It is found that for a wide range of ionic strengths these renormalized charges are clearly dependent on the length of the cations for nanoparticles with negative bare charge, but this dependence is practically negligible for nanoparticles with positive bare charges. In the limit of zero cation length and small nanoparticle charges the standard Derjaguin–Landau–Verwey–Overbeek model renormalization is recovered. A brief account of the structural and thermodynamic properties of the model molecular electrolyte is also provided.
The Role of Tax Incentives in Capital Investment and R&D Decisions
Authors: Chittenden Francis , Derregia Mohsen
Published: January 2010

In this paper we present the results from a study of the role that tax incentives play in business owners' decisions on capital investment and research and development (R&D) expenditure. We use semistructured interviews with fifteen business owners and directors and five financial advisers to establish the extent to which tax incentives are considered in capital and R&D investment decisions, and to identify obstacles that might prevent UK capital allowances and R&D tax policies from achieving their goals. First, we investigate whether incentives are sufficient to encourage investment and whether the costs of accessing the incentives faced by similar firms limit the potential benefits of the policy. Second, we explore the stage in the process of investment decision making at which tax issues are considered and the degree of importance attached to tax incentives. For example, is the tax treatment integral to the decision-making process or only a ‘final consideration’ at the end? Third, we investigate the impact of uncertainty on the tax incentives, since this can be an important aspect of investment decisions, and may diminish the effectiveness of policy. It is not clear whether the incentives offered are effective in generating additional investment and in helping financially constrained firms. Under uncertainty the incentives need to be substantial to influence the decision to invest. Effective policy should assist firms who would otherwise struggle to realise their business plans.
The Effect of Cognitive Distraction on Saccadic Latency
Authors: Halliday Jane , Carpenter Roger H S
Published: January 2010

Saccadic initiation is increasingly being studied as a surrogate for more general neural mechanisms of decision-making. Visual ‘decision-making’ is thought to be controlled by higher cortical functions. Lower areas such as the superior colliculus are thought to be involved with more primitive optomotor reflexes that can generate short-latency saccades. It is now well established that imposition of fronto-executive load on subjects performing a saccadic task which, in particular, involves suppression of saccades (the no-go saccadic task), increases the number of errors made. It is theorised that a weakening of cortical control of the superior colliculus is responsible for the increase in error rate. One way to test this theory is to measure the latency of incorrect saccades made in a no-go saccadic task in relation to error rate under different conditions of fronto-executive load. A high error rate combined with an increased number of short-latency saccades in the range of express or early saccades would indicate that subjects have an inability to inhibit these short-latency more reflexive saccades, which seem to originate in the superior colliculus. Hence the normal cortical control of the superior colliculus is weakened. We used a saccadic go/no-go task under fronto-executive load and found that the proportion of short-latency saccades increased with audio-verbal interference, in conjunction with an increase in error rate. These findings provide strong empirical evidence to support the theory that maintenance of cortical functions is key to the control of saccadic responses. Under conditions of fronto-executive loading such cortical control is weakened, leaving subjects with a reduced ability to inhibit short-latency more reflexive saccades.
Alternative Service Learning Approaches: Two Techniques That Accommodate Faculty Schedules
Authors: Heckert Teresa M.
Published: January 2010

A primary barrier to the usage of the well-documented pedagogical technique of service learning is time. Successful experiences require faculty to devote significant time to facilitating the community partnership. Another challenge is student readiness for experiences, both in terms of knowledge and motivation. In this article, 2 adaptations are discussed that expand the opportunities for service learning while preserving faculty time. The first strategy identifies internal community members, such as campus offices and organizations, as potential partners. A second strategy is to collaborate on an end product. This strategy preserves the benefits of indirect service learning. This article discusses the pragmatics, trade-offs, and lessons learned from using each of these strategies in class projects.
Do Student Perceptions of Diversity Emphasis Relate to Perceived Learning of Psychology?
Authors: Elicker Joelle D. , Snell Andrea F. , O'Malley Alison L.
Published: January 2010

We examined the extent to which students' perceived inclusion of diversity issues in the Introduction to Psychology course related to perceptions of learning. Based on the responses of 625 students, multilevel linear modeling analyses revealed that student perceptions of diversity emphasis in the class were positively related to how well students believed they understood concepts and the extent to which they believed they learned concepts they could apply to their lives. We also examined the relation between individual differences (e.g., age, race) and perceived learning. We discuss the importance of including issues of diversity in psychology classes.
Enhanced Learning and Retention through “Writing to Learn” in the Psychology Classroom
Authors: Stewart Tracie L. , Myers Ashley C. , Culley Marci R.
Published: January 2010

We assessed the benefits of employing microthemes—short in-class writing assignments designed to facilitate active learning—as pedagogical tools in psychology courses. Students in target course sections completed 10 in-class microthemes during a semester. We designed the microthemes to serve as active learning assignments that would enhance student learning and long-term retention, as well as strengthen students' writing skills. The instructors provided feedback to students on the content and writing quality of each microtheme. Students reported that the microthemes were effective and engaging learning tools. A comparison of essay and multiple-choice scores for students in target versus control course sections suggested the effectiveness of the microthemes for student learning, retention, and writing development.
The Undergraduate Psychology Major: An Examination of Structure and Sequence
Authors: Stoloff Michael , McCarthy Maureen , Keller Lizbeth , Varfolomeeva Veronika , Lynch Joanna , Makara Kara , Simmons Samantha , Smiley Whitney
Published: January 2010

Early study of the curriculum focused on the ideal array of experiences that should comprise the psychology major. We developed a standardized coding scheme to identify common curricula and course titles across institutions and current implementation of the curriculum. We compared psychology major programs in 2005 to programs described a decade earlier to evaluate the progress that has been made toward implementing published curriculum design recommendations. These data will aid departments in curriculum development and serve as a benchmark for common curriculum practices at this point in the evolution of the undergraduate psychology major in North America.
A racial comparison of Family Group Decision Making in the USA1
Authors: McCrae Julie S. , Fusco Rachel A.
Published: January 2010

This study examined Family Group Decision Making (FGDM) among a nationally representative sample of African‐American and White children investigated for maltreatment in the US. While FGDM was developed for work with ethnic minority families, there is no research on how this is being carried out in the US, where African‐American children are overrepresented in child welfare services. The study views racial differences in child, caregiver and maltreatment characteristics related to FGDM; composition of FGDM meetings; service referrals and receipt; and service satisfaction. Data are from the National Survey of Child and Adolescent Well‐being (NSCAW), a study of 5501 children ages 0–14. Current analyses include African‐American and White children (n= 4129). Stratified, bivariate and multivariate regression analyses were used. Results showed that while race was not related FGDM receipt, different characteristics lead to FGDM among African‐American and White families. Surprisingly, caregivers report feeling no more involved in decision‐making in association with FGDM. FGDM is provided at low rates overall (10%) and less frequently among White caseworkers. Child access to mental health services increases in relation to FGDM. Implications are discussed.
Epitope shift of proteinase-3 anti-neutrophil cytoplasmic antibodies in patients with small vessel vasculitis
Authors: Selga D , Segelmark M , Gunnarsson L , Hellmark T
Published: January 2010

Anti-neutrophil cytoplasmic antibodies against proteinase 3 (PR3-ANCA) are used as diagnostic tools for patients with small vessel vasculitis (AASV). We have produced chimeric mouse/human PR3 molecules and investigate changes in reactivity over time and the possible relationship between epitope specificity and clinical course. Thirty-eight PR3-ANCA-positive patients diagnosed between 1990 and 2003 were followed until December 2005. Plasma was collected at each out-patient visit and older samples were retrieved retrospectively. Patients reacted with multiple epitopes at the time of diagnosis. At subsequent relapses 12 patients shifted reactivity, in 11 cases from epitopes located in the C-terminal towards epitopes in the N-terminal. Patients with reactivity against N-terminal parts of PR3 at diagnosis had a significantly lower relapse rate, 30% compared to 78% in the group with predominantly C-terminal reactivity (P = 0·04). The reactivity pattern did not correlate to outcome measured as death, end-stage renal disease or vasculitis activity index score (VDI) at 5 years. Further research is necessary to conclude if this is a general phenomenon.
Microstructure investigations of dental composite samples prepared by focused ion beam technique
Authors: ANDRZEJCZUK M. , SIEJKA‐KULCZYK J. , LEWANDOWSKA M. , KURZYDŁOWSKI K.J.
Published: January 2010

In this study, microstructures of dental composites were observed using high resolution scanning transmission electron microscopy (HR STEM). Samples for these observations were prepared by focused ion beam system. Two kinds of dental composites were investigated: (1) polymer‐ceramic composite containing nano‐sized ceramic fillers and (2) ceramic‐polymer composite based on the nano‐structured yttrium stabilized zirconia. The first composite is a popular material for dental fillings whereas the second is used for the fabrication of fixed partial dentures. The results are discussed in terms of the evaluation of fabrication process of the composites.
Studies of aluminium coatings deposited by vacuum evaporation and magnetron sputtering
Authors: GARBACZ H. , WIECIŃSKI P. , ADAMCZYK‐CIEŚLAK B. , MIZERA J. , KURZYDŁOWSKI K.J.
Published: January 2010

The paper presents the results of investigations of the microstructures and properties of the aluminium coatings deposited by vacuum evaporation and magnetron sputtering. These coatings generally have a very refined microstructure with elongated nano‐grains. However, the surface topography of the aluminium coating deposited by vacuum evaporation is more developed, its microstructure is less homogeneous and more porous. The residual tensile stresses in the aluminium coating deposited by magnetron sputtering are close to 130 MPa, and the texture is relatively pronounced. Vacuum evaporation does not induce residual stresses in the coatings and the texture is very weak. The results obtained indicate that the aluminium coatings produced by magnetron sputtering are more suitable for the diffusive Ti‐Al intermetallic layers.
Microstructure and mechanical properties of Nb15Al10Ti alloy produced by mechanical alloying and high temperature processing
Authors: ROZMUS M. , BLICHARSKI M. , DYMEK S.
Published: January 2010

In this work, an Nb15Al10Ti alloy produced by mechanical alloying was investigated. The milling of elemental powders of Nb, Al as well as TiAl intermetallic phase resulted in the formation of homogenous niobium solid solution, Nbss, and refinement of powder particles. Powder after milling was consolidated by conventional hot pressing at 1300°C under pressure of 25 MPa as well as by hot isostatic pressing at 1200°C under pressure of 1 GPa. Microstructure of consolidated material was examined by transmission electron microscopy, scanning electron microscopy and X‐ray diffraction. Materials after consolidation were composed of three phases: niobium solid solution Nbss, Nb3Al intermetallic phase and titanium oxide dispersoid TiO. The analysis of the mechanical properties indicated that both refinement of microstructure as well as introduction of ductile Nbss into the microstructure contributed to very high yield strength and fracture toughness satisfactory for this strength.
Co‐occurring diagnoses among FMR1 premutation allele carriers
Authors: Hunter JE , Rohr JK , Sherman SL
Published: January 2010

Hunter JE, Rohr JK, Sherman SL. Co‐occurring diagnoses among FMR1 premutation allele carriers.

Following the discovery of two disorders associated with premutation alleles of the fragile X mental retardation gene (FMR1), primary ovarian insufficiency [fragile X‐associated primary ovarian insufficiency (FXPOI)] and a tremor/ataxia syndrome [fragile X‐associated tremor/ataxia disorder (FXTAS)], numerous studies have examined other potential co‐morbid conditions, including neuropsychological deficits. Here, the frequency of self‐reported diagnoses obtained through medical history interviews from FMR1 premutation carriers and non‐carriers aged 18–50 were analyzed. Study subjects included 537 women, 334 of whom carry the premutation and 151 men, 37 of whom carry the premutation. Men with the premutation did not report any medical conditions at higher rates compared with non‐carriers, controlling for age, ethnicity/race, and household income. Women with the premutation reported mental health disorders [i.e. attention deficit hyperactivity disorder (ADHD), anxiety, depression] significantly more often than non‐carriers. However, after adjusting for covariates, these increased rates were not statistically significant. Additional follow‐up analyses examined the consequence of ovarian dysfunction as a cause of co‐occurring conditions. Women with an indication of ovarian insufficiency (i.e. irregular cycles) reported higher rates of thyroid problems and depression/anxiety. Because only women, not men, reported these conditions more often, the relationship between FXPOI and hormone irregularities in women should be explored for a potential link with the increase in the reported medical conditions.
Hepatic effects of an open lung strategy and cardiac output restoration in an experimental lung injury
Authors: KREDEL M. , MUELLENBACH R. M. , HORNUNG A. , SCHMIDT R. , LAQUA J. , BREDERLAU J. , ROEWER N. , WUNDER C.
Published: January 2010

Background: Ventilation with high positive end‐expiratory pressure (PEEP) can lead to liver dysfunction. We hypothesized that an open lung concept (OLC) using high PEEP impairs liver function and integrity dependent on the stabilization of cardiac output.

Methods: Juvenile female Pietrain pigs instrumented with flow probes around the common hepatic artery and portal vein, pulmonary and hepatic vein catheters underwent a lavage‐induced lung injury. Ventilation was continued with a conventional approach (CON) using pre‐defined combinations of PEEP and inspiratory oxygen fraction or with an OLC using PEEP set above the lower inflection point of the lung. Volume replacement with colloids was guided to maintain cardiac output in the CON(V+) and OLC(V+) groups or acceptable blood pressure and heart rate in the OLC(V−) group. Indocyanine green plasma disappearance rate (ICG‐PDR), blood gases, liver‐specific serum enzymes, bilirubin, hyaluronic acid and lactate were tested. Finally, liver tissue was examined for neutrophil accumulation, TUNEL staining, caspase‐3 activity and heat shock protein 70 mRNA expression.

Results: Hepatic venous oxygen saturation was reduced to 18 ± 16% in the OLC(V−) group, while portal venous blood flow decreased by 45%. ICG‐PDR was not reduced and serum enzymes, bilirubin and lactate were not elevated. Liver cell apoptosis was negligible. Liver sinusoids in the OLC(V+) and OLC(V−) groups showed about two‐ and fourfold more granulocytes than the CON(V+) group. Heat shock protein 70 tended to be higher in the OLC(V−) group.

Conclusions: Open lung ventilation elicited neutrophil infiltration, but no liver dysfunction even without the stabilization of cardiac output.
A Behavioral Syndrome in the Adzuki Bean Beetle: Genetic Correlation Among Death Feigning, Activity, and Mating Behavior
Authors: Nakayama Satoshi , Miyatake Takahisa
Published: January 2010

When studying animal behavior, it is often necessary to examine traits as a package, rather than as isolated units. Evidence suggests that individuals behave in a consistent manner across different contexts or over time; that is, behavioral syndromes. We compared locomotor activity levels and mating success between beetles derived from two regimes artificially selected for the duration of death‐feigning behavior in the adzuki bean beetle, Callosobruchus chinensis. The two selection regimes comprised strains with higher (L) and lower (S) intensity (frequency and duration) of death‐feigning behavior, respectively. We found that S strains had higher activity levels than L strains for both sexes, i.e., there is a negative genetic correlation between death feigning and activity. In addition, we found that S strains had higher mating success than L strains, presumably due to higher activity, in males but not in females. We thus demonstrate that death feigning is genetically correlated to mating behavior in males but not females in this species, suggesting that behavioral correlations may not always reflect in the same way in both sexes.
Dual metal crankshaft for heavy‐duty engines by cast‐joining of DCI and forged steel
Authors: HAN S. , HUH H. , HAN G. T. , LEE J. S.
Published: January 2010

An alternative design of a crankshaft applicable for heavy‐duty diesel engines up to 5000 horsepower has been introduced to achieve cost effectiveness and manufacturing efficiency simultaneously not sacrificing its reliability. Because it is expensive and time consuming to make full‐scale prototype and run a test, analytical feasibility study has been made in this paper. From the point of material, cast‐joined dual metal for a crankshaft is totally unprecedented and will be realized by virtue of the latest dual metal cast joining of ductile cast iron (DCI) and forged steel, which consequently reduces the manufacturing lead time dramatically. The strength of the dual metal interface is experimentally investigated to make sure its possibility and soundness. The key features of the new crankshaft include crankpins and journals made of forged steel and crankwebs of DCI. Prior to actual manufacturing of the new conceptual crankshaft, the design is analytically examined to verify its reliability in an existing heavy‐duty engine. Both conventional and the new dual metal crankshafts are investigated and compared to each other in terms of the stress and fatigue using comprehensive multi‐body dynamic analysis. The results demonstrate that the new dual metal approach is likely to provide higher reliability than the conventional monometallic crankshafts. In addition, it is shown that the inferior mechanical properties of DCI for a crankweb are effectively countered by the superior characteristics of forged steel for a crankpin and journal in the dual metal crankshaft.
Dietary and lifestyle interventions for weight management in adults from minority ethnic/non‐White groups: a systematic review
Authors: Osei‐Assibey G. , Kyrou I. , Adi Y. , Kumar S. , Matyka K.
Published: January 2010

Minority ethnic/non‐White populations are more prone to weight gain and more susceptible to obesity‐related complications. The objective of this study was to systematically review dietary and lifestyle interventions for weight management in minority ethnic groups. Electronic databases and reference lists of original studies and reviews were searched for studies on dietary and lifestyle weight management interventions published. Randomized clinical trials with ≥6‐month duration were included. Nineteen studies met the inclusion criteria. Fourteen studies involved African–Americans, one in non‐White Hispanics, one in Japanese Americans and three in both African–Americans and non‐White Hispanics. Most of the interventions proved relatively effective. However, significant drawbacks were noted for several of these studies, such as small sample size, high attrition rates and lack of follow‐up data. Better quality and long‐term trials are required in order to investigate in detail the effectiveness of lifestyle changes for weight management in these populations and eventually support evidence‐based recommendations.
Adipokines and dietary interventions in human obesity
Authors: Klimcakova E. , Kovacikova M. , Stich V. , Langin D.
Published: January 2010

Obesity is a multisystem disorder associated with cardiovascular and metabolic complications. According to recent studies, it is characterized as a condition of low‐grade inflammation with altered adipose tissue function and secretion of various adipokines. One of the strategies in obesity treatment is dietary intervention (DI) that could modulate cytokine levels in a favourable way. The aim of this review was to summarize the results of studies performed in the last 13 years investigating DI programmes accompanied with weight loss in relation to profile of adipokines at different level (adipose tissue mRNA, adipose tissue secretion and circulating level) and identify whether modulations of adipokines are implicated in the positive effects of DIs. The overall finding is that DIs leading to 5–10% weight loss modulate production of certain adipokines and generally induce improvement of clinical parameters, e.g. insulin sensitivity, but the amelioration of obesity complications is not coherent with the pattern of adipokine regulation, except maybe for leptin. Global analysis of the adipose tissue secretome and measurement of panels of adipokines may prove more informative than studies on individual molecules.
Direct medical cost of overweight and obesity in the USA: a quantitative systematic review
Authors: Tsai A. G. , Williamson D. F. , Glick H. A.
Published: January 2010

To estimate per‐person and aggregate direct medical costs of overweight and obesity and to examine the effect of study design factors. PubMed (1968–2009), EconLit (1969–2009) and Business Source Premier (1995–2009) were searched for original studies. Results were standardized to compute the incremental cost per overweight person and per obese person, and to compute the national aggregate cost. A total of 33 US studies met review criteria. Among the four highest‐quality studies, the 2008 per‐person direct medical cost of overweight was $266 and of obesity was $1723. The aggregate national cost of overweight and obesity combined was $113.9 billion. Study design factors that affected cost estimates included use of national samples vs. more selected populations, age groups examined, inclusion of all medical costs vs. obesity‐related costs only, and body mass index cut‐offs for defining overweight and obesity. Depending on the source of total national healthcare expenditures used, the direct medical cost of overweight and obesity combined is approximately 5.0% to 10% of US healthcare spending. Future studies should include nationally representative samples, evaluate adults of all ages, report all medical costs and use standard body mass index cut‐offs.
Ordering and Selecting Components in Multivariate or Functional Data Linear Prediction
Authors: Hall Peter , Yang You-Jun
Published: January 2010

The problem of component choice in regression-based prediction has a long history. The main cases where important choices must be made are functional data analysis, and problems in which the explanatory variables are relatively high dimensional vectors. Indeed, principal component analysis has become the basis for methods for functional linear regression. In this context the number of components can also be interpreted as a smoothing parameter, and so the viewpoint is a little different from that for standard linear regression. However, arguments for and against conventional component choice methods are relevant to both settings and have received significant recent attention. We give a theoretical argument, which is applicable in a wide variety of settings, justifying the conventional approach. Although our result is of minimax type, it is not asymptotic in nature; it holds for each sample size. Motivated by the insight that is gained from this analysis, we give theoretical and numerical justification for cross-validation choice of the number of components that is used for prediction. In particular we show that cross-validation leads to asymptotic minimization of mean summed squared error, in settings which include functional data analysis.
Sexual Quality of Life of Individuals with 46,XY Disorders of Sex Development
Authors: Schönbucher Verena , Schweizer Katinka , Rustige Lisa , Schützmann Karsten , Brunner Franziska , Richter-Appelt Hertha
Published: January 2010

Introduction

There has recently been a growing acceptance that it is not only heterosexual functioning of surgically adjusted genitalia which should be considered when measuring the treatment outcome of persons with disorders of sex development (DSD) but also their overall sexual quality of life (SexQoL).

Aim

A comprehensive cross-sectional investigation of SexQoL of persons with 46,XY DSD.

Methods

Forty-seven persons with 46,XY DSD (age 17–60 years) were examined by means of a questionnaire on various aspects of SexQoL. Scores were compared to a nonclinical convenience sample consisting of 145 women. Data were analyzed separately for diagnostic subgroups. Furthermore, persons whose external genitalia had been surgically corrected were compared with persons whose genitalia had been left unaltered.

Main Outcome Measures

The Multidimensional Scale of Sexuality, the German Questionnaire on Feelings of Inadequacy in Social and Sexual Situations (FUSS), items on sexual dysfunctions according to DSM-IV-TR and self-constructed measures on sexual-activity history (e.g., previous sexual experience), sexual anxieties, and satisfaction with overall sex life and sexual function comprised the standardized assessment instruments.

Results

Compared with the nonclinical group, persons with 46,XY DSD had more often no partner (P = 0.056), felt more insecure in social (MdnDSD = 17.0, Mdncomparison = 12.0, P = 0.001) and sexual situations (MdnDSD = 17.0, Mdncomparison = 11.0, P = 0.006), had more sexual problems (MdnDSD = 4.0, Mdncomparison = 3.0, P = 0.001), and were less satisfied with overall sex life (MdnDSD = 3.0, Mdncomparison = 4.0, P = 0.000) and sexual function (MdnDSD = 4.0, Mdncomparison = 4.0, P = 0.000). Results were inconsistent with regard to sexual-activity history (e.g., previous sexual experience). Participants who underwent genital surgery showed less dyspareunia (P = 0.027) but more fear of injuries during intercourse (P = 0.019) than those whose genitals were left unaltered.

Conclusion

SexQoL of persons with 46,XY DSD may be impaired. Differences in SexQoL between diagnostic subgroups, effect of corrective genital surgery, and the influence of gender assignment will have to be further investigated in future studies.
Estimation of monthly diffuse nutrient loads for a watershed in Turkey
Authors: Gurel Melike , Erturk Ali , Seker Dursun Z. , Tanik Aysegul , Ekdal Alpaslan , Avsar Cigdem , Ozturk Izzet
Published: January 2010

Diffuse pollution has a complex nature depending on various land‐use activities like agriculture, livestock breeding and forestry. In this study, an alternative methodology is applied for decreasing the spatial uncertainty of diffuse nutrient load estimations. It is applied in the Melen Watershed, Turkey, which is an important watershed from where additional water will be supplied for the megacity Istanbul via interbasin water transfer. Monthly diffuse nutrient loads were estimated for each subwatershed by utilizing remote sensing (RS) and geographical information systems (GIS). Estimated nutrient loads were considerably different in various months due to the temporally irregular fertilizer application and meteorological conditions. Temporal differences were also predicted in the spatial distribution of the nutrient loads. The methodology is applicable in watershed protection studies, especially where necessary etudes should be conducted in the short term and with limited data. Such efforts in identifying and determining the diffuse loads are important for sustainable management of the watershed.
Application of Agonist‐Receptor Modeling to the Sweetness Synergy between High Fructose Corn Syrup and Sucralose, and between High‐Potency Sweeteners
Authors: Wolf P.A. , Bridges J.R. , Wicklund R.
Published: January 2010

ABSTRACT:  The agonist‐receptor‐transducer model of D. Ennis is applied to beverage formulations sweetened with high fructose corn syrup, sucralose, and other high‐potency sweeteners, confirming the utility of the model, and supports the growing volume of evidence for multiple binding sites on the sweetness receptor. The model is further simplified to require less parameters for other sweetener blend systems whenever potency information is available for the single sweeteners.