bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of Multiobjective Genetic Algorithms With Different Niching Strategies and Regression Methods for Engine Optimization and Design
Authors: Shi Yu , Reitz Rolf D.
Published: March 2010

In a previous study (Shi, Y., and Reitz, R. D., 2008, “Assessment of Optimization Methodologies to Study the Effects of Bowl Geometry, Spray Targeting and Swirl Ratio for a Heavy-Duty Diesel Engine Operated at High-Load,” SAE Paper No. 2008-01-0949), nondominated sorting genetic algorithm II (NSGA II) (Deb, K., Pratap, A., Agarwal, S., and Meyarivan, T., 2002, “A Fast and Elitist Multiobjective Genetic Algorithm: NSGA-II,” IEEE Trans. Evol. Comput., 6, pp. 182–197) performed better than other popular multiobjective genetic algorithms (MOGAs) in engine optimization that sought optimal combinations of the piston bowl geometry, spray targeting, and swirl ratio. NSGA II is further studied in this paper using different niching strategies that are applied to the objective space and design space, which diversify the optimal objectives and design parameters, accordingly. Convergence and diversity metrics are defined to assess the performance of NSGA II using different niching strategies. It was found that use of design niching achieved more diversified results with respect to design parameters, as expected. Regression was then conducted on the design data sets that were obtained from the optimizations with two niching strategies. Four regression methods, including K-nearest neighbors (KNs), kriging (KR), neural networks (NNs), and radial basis functions (RBFs), were compared. The results showed that the data set obtained from optimization with objective niching provided a more fitted learning space for the regression methods. KNs and KR outperformed the other two methods with respect to prediction accuracy. Furthermore, a log transformation to the objective space improved the prediction accuracy for the KN, KR, and NN methods, except the RBF method. The results indicate that it is appropriate to use a regression tool to partly replace the actual CFD evaluation tool in engine optimization designs using the genetic algorithm. This hybrid mode saves computational resources (processors) without losing optimal accuracy. A design of experiment (DoE) method (the optimal Latin hypercube method) was also used to generate a data set for the regression processes. However, the predicted results were much less reliable than the results that were learned using the dynamically increasing data sets from the NSGA II generations. Applying the dynamical learning strategy during the optimization processes allows computationally expensive CFD evaluations to be partly replaced by evaluations using the regression techniques. The present study demonstrates the feasibility of applying the hybrid mode to engine optimization problems, and the conclusions can also extend to other optimization studies (numerical or experimental) that feature time-consuming evaluations and have highly nonlinear objective spaces.
A Numerical Investigation of Transient Flow and Cavitation Within Minisac and Valve-Covered Orifice Diesel Injector Nozzles
Authors: Lee Won Geun , Reitz Rolf D.
Published: March 2010

Cavitating flow within diesel injector passages has been investigated numerically using the homogeneous equilibrium model (HEM), which uses the barotropic assumption and the variable speed of sound of the mixture. To apply the HEM, the KIVA-3V code was modified to implement a generalized equation of state, and injector needle movement is simulated by the arbitrary Lagrangian-Eulerian (ALE) approach and the snapper algorithm. It is demonstrated that the model can predict the effect of nozzle passage geometry on the flow structure and cavitation. The model is able to reproduce the transient fuel injection rate as a function of the needle lift profile. Special interest is focused on the transient behavior during the nozzle closing period, which shows that the fast decrease in flow rate can increase the cavitation in the nozzle passage. The effects of the pressure difference and environment pressure on cavitation augmentation at the end-of-injection were also investigated. Flow characteristics due to different shapes of the nozzle flow passage in axisymmetric single hole nozzles and multihole nozzle configurations (minisac and valve-covered orifice eight-hole nozzles) were compared with emphasis on the end-of-injection period.
Modeling of Dynamically Loaded Open-Cell Metallic Foams: Yielding, Collapse, and Strain Rate Effects
Authors: Romero Pedro A. , Soboyejo Winston O. , Cuitiño Alberto M.
Published: March 2010

Open-cell metallic foams exhibit properties desirable in engineering applications requiring mitigation of the adverse effects resulting from impact loading; however, the history dependent dynamic response of these cellular materials has not been clearly elucidated. This article contributes an approach for modeling the response of dynamically loaded open-cell metallic foams from ligament level to unit cell level to specimen level. The effective response captures the localized chaotic collapse phenomena through ligament reorientation at cell level while maintaining the history of plastic deformation at ligament level. First, the phenomenological elastoplastic constitutive behavior of the ligaments composing the unit cell is modeled. Then, using the constitutive ligament model, the effective unit cell response is obtained from a micromechanical model that enforces the principle of minimum action on a representative 3D unit cell. Finally, the macroscopic specimen response is predicted utilizing a finite element analysis program, which obtains the response at every Gauss point in the mesh from the microscopic unit cell model. The current communication focuses on the ability of the model to capture the yielding and collapse behaviors, as well as the strain rate effects, observed during impact loading of metallic foams.
Recursive Differential Systems in Nonlinear Mechanics
Authors: David Claire , Marcilhac Marine , Rigolot Alain
Published: March 2010

The classical strength of materials for beams is represented through the first two terms of the asymptotic expansion of the solution of Navier’s equations. The method of asymptotic expansions with respect to the inverse of the slenderness of the beam permits us to obtain an approximate solution of Saint-Venant’s problem. For the elasticity of the second order, the displacement field is obtained as the sum of a series, the general term of which at the nth order is the solution of a differential recursive system. We presently propose a general way of solving this kind of system. The exact solution is given explicitly in the case of a slender field (beam).
Polar Orthotropic Inhomogeneous Circular Plates: Vibration Tailoring
Authors: Pentaras Demetris , Elishakoff Isaac
Published: March 2010

Problem of matching a desired fundamental natural frequency is solved in the closed form for the polar-orthotropic inhomogeneous circular plate, which is clamped along its circumference. The vibration tailoring is performed by posing a semi-inverse eigenvalue problem. To do this, the fundamental mode shape is postulated. Namely, the analytical expression due to Lekhnitskii, and pertaining to the static deflection of the homogeneous circular plate is demanded to serve as an exact mode shape of the inhomogeneous plate. The analytical and numerical results are reported for several ratios of orthotropic coefficient.
Hybrid Randomness of Initial Imperfections and Axial Loading in Reliability of Cylindrical Shells
Authors: Elishakoff Isaac , Andriamasy Lova , Lemaire Maurice
Published: March 2010

This study investigates the combined effect of randomness in initial geometric imperfections and the applied loading on the reliability of axially compressed cylindrical shells. In order to gain insight we consider simplest possible case when both the initial imperfections and the applied loads are uniformly distributed. It is shown that hybrid randomness may increase or decrease the reliability of the shell if the latter is treated, experiencing the sole randomness in initial imperfections.
A Note on the Effect of the Choice of Weak Form on GMRES Convergence for Incompressible Nonlinear Elasticity Problems
Authors: Pathmanathan Pras , Whiteley Jonathan P. , Chapman S. Jonathan , Gavaghan David J.
Published: March 2010

The generalized minimal residual (GMRES) method is a common choice for solving the large nonsymmetric linear systems that arise when numerically computing solutions of incompressible nonlinear elasticity problems using the finite element method. Analytic results on the performance of GMRES are available on linear problems such as linear elasticity or Stokes’ flow (where the matrices in the corresponding linear systems are symmetric), or on the nonlinear problem of the Navier–Stokes flow (where the matrix is block-symmetric/block-skew-symmetric); however, there has been very little investigation into the GMRES performance in incompressible nonlinear elasticity problems, where the nonlinearity of the incompressibility constraint means the matrix is not block-symmetric/block-skew-symmetric. In this short paper, we identify one feature of the problem formulation, which has a huge impact on unpreconditioned GMRES convergence. We explain that it is important to ensure that the matrices are perturbations of a block-skew-symmetric matrix rather than a perturbation of a block-symmetric matrix. This relates to the choice of sign before the incompressibility constraint integral in the weak formulation (with both choices being mathematically equivalent). The incorrect choice is shown to have a hugely detrimental effect on the total computation time.
Actuated Bistable Jumping Structures
Authors: Santer Matthew
Published: March 2010

The design and analysis of a fully actuated adaptive bistable structure is presented. This structure releases energy at a high frequency, which in consequence causes it to jump. Such structures have application as the basis for multistable adaptive systems. The dynamic transition of the bistable structure from its high-energy to low-energy stable states and the lower-frequency return transition are considered by reference to a specific example. The effect of embedded actuation on this behavior is also investigated.
Deformations and Stability of an Elastica Subjected to an Off-Axis Point Constraint
Authors: Chen Jen-San , Ro Wei-Chia
Published: March 2010

This paper studies, both theoretically and experimentally, the deformation, the vibration, and the stability of a buckled elastic strip (also known as an elastica) constrained by a space-fixed point in the middle. One end of the elastica is fully clamped while the other end is allowed to slide without friction and clearance inside a rigid channel. The point constraint is located at a specified height above the clamping plane. The elastic strip buckles when the pushing force reaches the conventional buckling load. At this buckling load, the elastica jumps to a symmetric configuration in contact with the point constraint. As the pushing force increases, a symmetry-breaking bifurcation occurs and the elastica evolves to one of a pair of asymmetric deformations. As the pushing force continues to increase, the asymmetric deformation experiences a second jump to a self-contact configuration. A vibration analysis based on an Eulerian description taking into account the sliding between the elastica and the point constraint is described. The natural frequencies and the stability of the calculated equilibrium configurations can then be determined. The experiment confirms the two jumps and the symmetry-breaking bifurcation predicted theoretically.
PDMS-Glass Interface Adhesion Energy Determined Via Comprehensive Solutions for Thin Film Bulge/Blister Tests
Authors: Sofla Aarash , Seker Erkin , Landers James P. , Begley Matthew R.
Published: March 2010

This paper provides comprehensive relationships for pressure, deflection, energy release rate, and phase angle for bulge testing, which are valid for all combinations of the testing length-scales (film thickness, debond size, and bulge height) and materials. These solutions can be used to design experiments that vary relative contributions of opening and sliding displacements at the crack tip by modulating the film thickness, debond size, and bulge volume. Their closed-form nature greatly facilitates property extraction via regression, e.g., modulus from experimental pressure/deflection data or interface toughness from debond size/injected volume data. This is illustrated using experiments to quantify the interfacial adhesion energy between an initially dry polydimethylsiloxane-glass interface via bulge testing under controlled volume injection. The results indicate that the mode-mixity has no effect on the energy required for debonding, which suggests that wetting of the crack faces behind the debonding front eliminates friction.
Experimental and Theoretical Study of Ventilation and Heat Loss From Isothermally Heated Clothed Vertical Cylinder in Uniform Flow Field
Authors: Ghaddar Nesreen , Ghali Kamel , Al-Othmani Mohamad , Holmer Ingvar , Kuklane Kalev
Published: March 2010

The flow characteristics and heat transfer are studied in a vertical annulus of a heated cylinder surrounded by a permeable cylinder, subject to cross uniform wind with open end to the environment and in the presence of natural convection. The objective here is to develop a computationally efficient model capable of capturing the physics of the flow and heat transport to predict air renewal rates in the vertical annulus. The small quantities of air infiltrating/exfiltrating through the porous cylinder over its upstream/downstream regions do not substantially affect the external flow pattern around the clothed cylinder. The air annulus flow and heat transport model predicted the radial and vertical mass fluxes and the mass flow rate at the opening as a function of environment conditions, porous cylinder thermal properties, wind speed, and annulus geometry. Experiments were performed in a low speed wind tunnel (0.5–5 m/s), in which an isothermally heated vertical cylinder surrounded by a clothed outer cylinder was placed in uniform cross wind. The tracer gas method is used to predict total ventilation flow rates through the fabric and the opening. Good agreement was found between the model and experimental measurements of air renewal rate and predicted heat loss from the inner cylinder at steady conditions. A parametric study is performed to study the effect of wind speed and temperature difference between the wind and skin temperature on induced ventilation through the clothing and the opening. It is found that natural convection enhances ventilation of the annulus air at wind speed, less than 3 m/s, while at higher speeds, natural convection effect is negligible. As the temperature difference between external wind and inner cylinder surface increases, the vertical air temperature gradient and total upward airflow through the opening increase.
Wrinkling of Tubes by Axial Cycling
Authors: Jiao Rong , Kyriakides Stelios
Published: March 2010

Circular tubes compressed into the plastic range first buckle into axisymmetric wrinkling. Initially, the wrinkle amplitude grows with increasing load, but induces a gradual reduction in axial rigidity that eventually leads to a limit load instability and collapse. For lower D/t tubes, the two instabilities can be separated by strain levels of a few percent. Persistent stress-controlled cycling can cause accumulation of deformation by ratcheting. Here, the interaction of ratcheting and wrinkling is investigated. In particular, it is asked if compressive ratcheting can first initiate wrinkling and then grow it to amplitudes associated with collapse. Experiments on SAF2507 super-duplex steel tubes with D/t of 28.5 have shown that a geometrically intact tube cycled under stress control initially deforms uniformly due to material ratcheting. However, in the neighborhood of the critical wrinkling strain under monotonic loading, small amplitude axisymmetric wrinkles develop. This happens despite the fact that the maximum stress of the cycles can be smaller than the critical stress under monotonic loading. In other words, wrinkling appears to be strain rather than stress driven, as is conventionally understood. Once the wrinkles are formed, their amplitude grows with continued cycling, and as a critical value of amplitude is approached, wrinkling localizes, the rate of ratcheting grows exponentially, and the tube collapses. Interestingly, collapse was also found to occur when the accumulated average strain reaches the value at which the tube localizes under monotonic compression. A custom shell model with small initial axisymmetric imperfections, coupled to a cyclic plasticity model, is used to simulate these cyclic phenomena successfully.
Model for aspect ratio dependent etch modulated processing
Authors: Gilgunn Peter J. , Alfaro J. Fernando , Fedder Gary K.
Published: March 2010

A time-multiplexed, anisotropic, inductively coupled plasma Si deep reactive ion etch process is characterized in terms of the Si macroload, cross-wafer spatial variation, local pattern density, and feature size. The process regime is established as neutral flux limited, in which material transport occurs in the molecular flow to transition flow regimes. For this process regime, a semiempirical, unified analytic model and a numeric model are developed using the Dushman and Clausing vacuum conductance correction factors, respectively, in the Coburn and Winters model of aspect ratio dependent etching. The experimental reaction probability for etching of Si by F was found to be 0.24 for Dushman’s factor and 0.22 for Clausing’s factor. Each model is validated to ±10% against experimental depth data for microdonut and trench test structures and match each other to within 10% for depths of up to 160 μm. The observed depth range is 64 μm at a depth of 160 μm.
Metabolic Syndrome and Altered Gut Microbiota in Mice Lacking Toll-Like Receptor 5
Authors: Vijay-Kumar Matam , Aitken Jesse D. , Carvalho Frederic A. , Cullender Tyler C. , Mwangi Simon , Srinivasan Shanthi , Sitaraman Shanthi V. , Knight Rob , Ley Ruth E. , Gewirtz Andrew T.
Published: March 2010

Debugging Metabolic Disease

Obesity, now officially recognized as an epidemic in many developed nations, is a key component of “metabolic syndrome,” an array of metabolic disturbances that increase an individual's risk of developing diabetes and heart disease. The rise in obesity rates has been largely attributed to the growing imbalance between food intake and energy expenditure, but recent provocative work has suggested a possible link between obesity and the composition of microbes residing within the gut.

Vijay-Kumar
et al.

(p.
228
, published online 4 March; see the Perspective by

Sandoval and Seeley

) now find that mutant mice deficient in a component of the innate immune system (which defends the body against microbial pathogens) develop hallmark features of metabolic syndrome, accompanied by changes in gut microbiota. Notably, transfer of gut microbiota from the mutant mice to wild-type mice conferred several features of metabolic syndrome to the recipients. Thus, the development of metabolic syndrome may indeed be influenced by gut microbes that are regulated by the innate immune system.
Iron-Clad Fibers: A Metal-Based Biological Strategy for Hard Flexible Coatings
Authors: Harrington Matthew J. , Masic Admir , Holten-Andersen Niels , Waite J. Herbert , Fratzl Peter
Published: March 2010

Mussel Fibers

While it is possible to make strong fibers or threads from organic materials, most suffer from high wear abrasion. Marine mussels attach themselves to rocky seashores using a series of byssal threads. Despite the constant rubbing caused by the motion of the tides, the threads show high wear resistance.
Harrington et al.
(p.
216
, published online 4 March; see the Perspective by

Messersmith

) now find that the threads are protected by a proteinaceous outer cuticle that is rich in the amino acid 3,4-dihydroxyphenylalanine (dopa), which is known to be a strong adhesive. The cuticle is also rich in metal ions, primarily Fe
3+
. The dopa-metal crosslinks helped to form the tough outer coating.
Cryptic Sex-Ratio Bias Provides Indirect Genetic Benefits Despite Sexual Conflict
Authors: Cox Robert M. , Calsbeek Ryan
Published: March 2010

The Size of the Father

Evolutionary biologists have recently discovered an intriguing phenomenon: High-fitness males often sire low-fitness daughters. The emerging consensus is that this sexual conflict overwhelms the benefits of mate choice for “good genes,” thus challenging a central tenet of evolutionary theory.
Cox and Calsbeek
(p.
92
, published online 4 March) provide a counterpoint by showing that female brown anole lizards can obtain genetic benefits by biasing offspring sex to produce disproportionately more sons with high-fitness (large) sires. The advantage of this sex-ratio bias was confirmed by tracking the fitness of sons and daughters in their natural environment, illustrating the importance of sexual conflict in the wild. Thus, because maximal fitness payoffs can be achieved by shifting offspring production from daughters to sons as sire size increases, mate choice can overcome antagonistic fitness effects.
Sunscreen for the Young Earth
Authors: Jardine Moira
Published: March 2010

Dating the establishment of Earth's magnetic field has implications for identifying conditions when life could take hold.
Treatment as Prevention
Authors: Cohen Jon
Published: March 2010

At the 17th Conference on Retroviruses and Opportunistic Infections, two groups presented some of the firmest data yet to support the concept of testing everyone for HIV and immediately starting all infected people on treatment.
Conservation genetics of Pitcher’s thistle (Cirsium pitcheri), an endangered Great Lakes endemic
Authors: Gauthier Martha , Crowe Emily , Hawke Lindsey , Emery Neil , Wilson Paul , Freeland Joanna
Published: March 2010

Pitcher's thistle ( Cirsium pitcheri Torr. ex Eaton (Torr. & Gray)) is a Great Lakes endemic that in Canada is designated as threatened at both the provincial (Ontario) and national levels. Management plans will benefit from conservation genetic data, which can provide insight into population genetic diversity and differentiation. We obtained genetic data from nuclear and chloroplast microsatellite markers from 17 populations of C. pitcheri around the Great Lakes. The nuclear data revealed overall low levels of diversity, high levels of inbreeding, and low levels of population connectivity. The chloroplast data identified a single haplotype, which is consistent with reduced genetic diversity following postglacial colonization. The high levels of inbreeding within populations will likely pose a serious threat to populations in the short term; these have resulted from a combination of low connectivity between populations, and small and fluctuating population sizes. Future management of C. pitcheri populations should consider human-mediated dispersal of plants or seeds among sites.
Differences in initial root development and soil conditions affect establishment of trembling aspen and balsam poplar seedlings
Authors: Wolken Jane M. , Landhäusser Simon M. , Lieffers Victor J. , Dyck Miles F.
Published: March 2010

Three studies examined the establishment and early growth of trembling aspen ( Populus tremuloides Michx.) and balsam poplar ( Populus balsamifera L.) from seed. To better understand the differences in initial developmental patterns between both species, we monitored germination and early growth in a washed sand medium with a balanced fertilizer added. Two additional studies used the Ae, Bm, and Bt horizons of a Brunisolic Gray Luvisol soil to test the impact of different soil horizons and conditions (compaction and moisture) on the establishment and early growth of trembling aspen and balsam poplar seedlings. Balsam poplar had faster radicle and leaf area development than trembling aspen and grew similarly in all soil horizons, while trembling aspen only grew well in the Ae horizon, where it outgrew balsam poplar. The superior growth of trembling aspen in the Ae horizon was associated with higher P and organic C relative to the lower horizons. Although germination was lowest on the low-compaction – low-moisture treatment for both species, balsam poplar establishment and early growth were higher than for trembling aspen in all combinations of compaction and moisture. Compared with trembling aspen, the wider establishment niche of balsam poplar is attributed to its faster root development and ability to grow in a range of soil substrates and conditions.
STRAIN DISTRIBUTION AND ELECTRONIC STRUCTURE OF SELF-ORGANIZEDInAs/GaAsQUANTUM DOTS
Authors: LIU YUMIN , XU ZIHUAN , YU ZHONGYUAN , JIA BOYONG , LU WENJUAN , LU PENGFEI , HAN LIHONG
Published: March 2010

This paper presents a finite element method for calculating the strain distribution, piezoelectric effects and their influences on the electronic structure of self-organized InAs/GaAs quantum dots. The models used for strain calculations are based on the continuum elastic theory, which is capable of treating the quantum dot of arbitrary shapes. A truncated pyramid shaped quantum dot model including the wetting layer is adopted in this work. The electronic energy levels of the InAs/GaAs systems are calculated by solving the three-dimension effective mass Schrödinger equation including the influences on the modification of conduction band edge due to the strain and piezoelectricity. The calculated results indicate that both strain and piezoelectric effects should be considered, especially in treating the electronic structure and optical characteristics for device applications.
THE STRAIN FIELD DISTRIBUTION OF QUANTUM DOT ARRAY WITH CONICAL SHAPE
Authors: LIU YUMIN , LU WENJUAN , YU ZHONGYUAN , JIA BOYONG , XU ZIHUAN , LU PENGFEI , HAN LIHONG
Published: March 2010

A systematic investigation is given about the effects of the longitudinal and transverse periodic distributions on the elastic strain field. The results show that the influences of the longitudinal and transverse period on the strain field are just opposite, especially for the path along the center-axis of the quantum dots. In the proper conditions, the influence of periodicity on strain field distribution can be partly eliminated. The results demonstrate that when calculating the effect of the strain field on the electronic structure, one must take the quantum dots periodic distribution into account. It is unsuitable to use the isolated quantum dot model in simulating the strain field and evaluate the influence on electronic structure.
SELF-ASSEMBLED VOLUME GRATING IN SILICA GLASS INDUCED BY TIGHTLY FOCUSED FEMTOSECOND LASER PULSE
Authors: GUO ZHONGYI , DING WEIQIANG , QU SHILIANG , DAI JINGMIN , LIU SHUTIAN
Published: March 2010

We report on self-assembled volume grating in silica glass induced by a tightly focused femtosecond laser pulse. The formation of volume grating is attributed to the multiple microexplosion in the transparent materials induced by the femtosecond pulses. The first order diffractive efficiency is greatly dependent on the energy of the pulses and the scanning velocity of the laser, and the highest reaches to nearly 30%.
LUMINESCENCE CHARACTERISTICS OF RARE-EARTH ERBIUM ION-DOPED NANOCRYSTALLINE ZINC OXIDE
Authors: GUO-LI SONG
Published: March 2010

Er3+-doped ZnO nanocrystalline powders are successfully prepared by the chemical precipitation method, using various doping concentrations of Er3+at different annealing temperatures from 500°C to 900°C. The characteristic emission peaks of the excitation state4S3/2(550 nm),2H11/2(520 nm),4F5/2(455 nm) →4I15/2transition of Er3+ions are observed in a wide visible band of the ZnO host. The relationship between the PL intensity of integration of nanocrystalline ZnO:Er3+and the annealing temperature and doping concentration of Er3+is given; it is found that the optimal dopant concentration and annealing temperature are 4.0 × 10-3M and 850°C for the4S3/2→4I15/2(550 nm) and4F5/2→4I15/2(455 nm) transition of Er3+. Based on these results, the mechanism of the emission spectra of ZnO is analyzed and its defects on the spectral properties are discussed. An energy transfer from excited states of ZnO hosts to doping Er3+ion centers is revealed by the fact that PL intensity of the peaks of nanocrystalline ZnO:Er3+changes with the annealing temperature and doping concentration of Er3+, and another from the 4f–4f transition of Er3+.
NONLINEAR-OPTICAL AND OPTICAL LIMITING PROPERTIES OF PHENOXY-PHTHALOCYANINES STUDIED USING THE Z-SCAN TECHNIQUE
Authors: ZHANG YUNDONG , MA LEI , YANG CHAOBO , YUAN PING
Published: March 2010

The nonlinear-optical and optical limiting properties of 2(3), 9(10), 16(17), 23(24) phenoxy-phthalocyanines have been investigated using a 10-ns-pulse laser at 532 nm. The nonlinear absorption coefficient (β) is measured by the single beam Z-scan technique. We have observed low power optical limiting, with low limiting thresholds, based on nonlinear absorption in the sample. These studies indicate that the phthalocyanine material is a potential candidate for low power optical limiting applications.
BROADBAND PUMP–PROBING INSIDE AN OPTICAL PARAMETRIC AMPLIFIER
Authors: RIORDON JASON , BASQUE VINCENT , HACHÉ ALAIN
Published: March 2010

We use an optical parametric amplifier to obtain and demonstrate a fast and flexible pump–probe system with minimal conversion needed. The readily aligned laser may be used to quickly test samples with broadband pump–probing as well as femtosecond time-resolved spectroscopy. As a proof of concept, we produce results on optical modulation in vanadium dioxide thin films similar to that previously obtained by other groups.
LIGHT SELF-LOCALIZATION IN NEMATIC LIQUID CRYSTALS: MODELLING SOLITONS IN NONLOCAL REORIENTATIONAL MEDIA
Authors: ASSANTO GAETANO , MINZONI ANTONMARIA A. , SMYTH NOEL F.
Published: March 2010

We review the mathematical modelling of propagation and specific interactions of solitary beams in nematic liquid crystals — so-called nematicons. The theory is first developed for the evolution of a single nematicon; then it is extended to the interaction of two nematicons of different wavelengths, employing linear momentum conservation equations to predict that two colour nematicons can form a vector bound state. Considering optical vortices, we show that the nonlocal response of liquid crystals stabilises a single vortex, unstable in local media. Moreover, the interaction with a nematicon in another colour can stabilise a vortex for nonlocalities far below those at which an isolated vortex remains unstable. When multiple nematicons of the same wavelength interact, the radiation they shed can join them together, still resulting in a vortex. Finally, we discuss the escape of a nematicon from a nonlinear waveguide, using simple modulation theory based on momentum conservation to model the effect and get excellent agreement with the experimental results.
SNPS IN THE HIV-1 TATA BOX AND THE AIDS PANDEMIC
Authors: SUSLOV VALENTIN V. , PONOMARENKO PETR M. , EFIMOV VADIM M. , SAVINKOVA LUDMILA K. , PONOMARENKO MIKHAIL P. , KOLCHANOV NIKOLAY A.
Published: March 2010

Evolutionary trends have been examined in 146 HIV-1 forms (2662 copies, 2311 isolates) polymorphic for the TATA box using the "DNA sequence→affinity for TBP" regression (TBP is the TATA binding protein). As a result, a statistically significant excess of low-affinity TATA box HIV-1 variants corresponding to a low level of both basal and TAT-dependent expression and, consequently, slow replication of HIV-1 have been detected. A detailed analysis revealed that the excess of slowly replicating HIV-1 is associated with the subtype E-associated TATA box core sequence "CATAAAA". Principal Component Analysis performed on 2662 HIV-1 TATA box copies in 70 countries revealed the presence of two principal components, PC1 (75.7% of the variance) and PC2 (23.3% of the variance). They indicate that each of these countries is specifically associated with one of the following trends in HIV-1 evolution: neutral drift around the normal TATA box; neutral drift around the slowly replicating TATA box core sequence (phylogenetic inertia); an adaptive increase in the frequency of the slowly replicating form.
Fast Eight-Domain Patterned Vertical Alignment Mode with Reactive Mesogen for a Single-Transistor-Driving
Authors: Lee You-Jin , Jo Soo In , Kim Jae-Hoon , Yu Chang-Jae
Published: March 2010

We proposed a wide-viewing patterned vertical alignment (PVA) mode with eight-domains driven by a single transistor. The eight-domain PVA mode was fabricated by introducing two different pretilt angles in a pixel using polymerized reactive mesogens (RMs) within alignment layer. The pretilt angles are simply controlled by an applied voltage during illumination of ultraviolet light for polymerization of the RMs. In addition, the polymerized RMs give rise to defect-free transition in our advanced PVA mode and thus fast response can be achieved over whole grey level.
Optoelectronic Characteristics of HgSe Nanoparticle Films Spin-Coated on Flexible Plastic Substrates
Authors: Jang Jaewon , Cho Kyoungah , Byun Kwangsub , Hong Wan-Shick , Kim Sangsig
Published: March 2010

The optoelectronic characteristics of HgSe nanoparticle films spin-coated on plastic substrates are investigated in this work. The photocurrent of a representative HgSe nanoparticle film under the illumination of 633-nm wavelength light is 10 times larger than the dark current in air at room temperature. In addition, the effects of bending on the optoelectronic characteristics of the HgSe nanoparticle film are examined by applying tensile and compressive strains to the plastic substrate.
T-type Ca2+channel modulation by otilonium bromide
Authors: Strege Peter R. , Sha Lei , Beyder Arthur , Bernard Cheryl E. , Perez-Reyes Edward , Evangelista Stefano , Gibbons Simon J. , Szurszewski Joseph H. , Farrugia Gianrico
Published: March 2010

Antispasmodics are used clinically to treat a variety of gastrointestinal disorders by inhibition of smooth muscle contraction. The main pathway for smooth muscle Ca2+entry is through L-type channels; however, there is increasing evidence that T-type Ca2+channels also play a role in regulating contractility. Otilonium bromide, an antispasmodic, has previously been shown to inhibit L-type Ca2+channels and colonic contractile activity. The objective of this study was to determine whether otilonium bromide also inhibits T-type Ca2+channels. Whole cell currents were recorded by patch-clamp technique from HEK293 cells transfected with cDNAs encoding the T-type Ca2+channels, CaV3.1 (α1G), CaV3.2 (α1H), or CaV3.3 (α1I) alpha subunits. Extracellular solution was exchanged with otilonium bromide (10−8to 10−5M). Otilonium bromide reversibly blocked all T-type Ca2+channels with a significantly greater affinity for CaV3.3 than CaV3.1 or CaV3.2. Additionally, the drug slowed inactivation in CaV3.1 and CaV3.3. Inhibition of T-type Ca2+channels may contribute to inhibition of contractility by otilonium bromide. This may represent a new mechanism of action for antispasmodics and may contribute to the observed increased clinical effectiveness of antispasmodics compared with selective L-type Ca2+channel blockers.
Clinical Features and Treatment Outcomes of Vitiligo from the Patients’ Perspective: Results of a National Survey in Germany
Authors: Radtke Marc A. , Schäfer Ines , Gajur Angelika I. , Augustin Matthias
Published: March 2010

Background: Vitiligo causes substantial disease burden and patient needs still remain underestimated. Objective: To assess the clinical features, treatment outcomes and satisfaction in patients with vitiligo. Methods: A nationwide, cross-sectional German postal survey was conducted. Clinical features and treatment outcomes of vitiligo (affected body surface, comorbidities, treatments applied, patient benefit index [PBI]) were evaluated using a standardized patient questionnaire. Results: 1,023 patients (71.4% women, mean age 44.4 years) completed the questionnaire. The average onset of disease was at 24.1 years, and the mean disease duration was 20.3 years. The mean number of body sites affected was 6.9, and the mean affected body surface area was 14.9%. On average, 3.7 therapies had been applied previously, with a total PBI of 1.03 ± 1.12. Only 38.7% experienced a PBI >1, which indicates a minimal patient benefit. Conclusions: Most therapeutic options are considered to be of low patient benefit. There is a need for more beneficial treatments and improved care in patients with vitiligo.
Splice Site Mutations in the P-Cadherin Gene Underlie Hypotrichosis with Juvenile Macular Dystrophy
Authors: Shimomura Y. , Wajid M. , Kurban M. , Christiano A.M.
Published: March 2010

Background: Hypotrichosis with juvenile macular dystrophy (HJMD; OMIM 601553) is a rare autosomal recessive disorder characterized by hypotrichosis with short scalp hair and progressive macular dystrophy leading to blindness between the second and the fourth decades of life. HJMD is caused by mutations in the P-cadherin gene (CDH3), a member of the family of classical cadherins. Methods: We analyzed the DNA from members of 2 consanguineous Pakistani families with HJMD for mutations in the P-cadherin gene through direct sequencing. Results: We identified 2 splice site mutations in the P-cadherin gene in these families. One was a novel mutation, Ivs12-2A→G and the other a recurrent mutation, Ivs10-1G→T. A screening assay for the novel mutation ruled out the possibility of a polymorphism. Using haplotype analysis, we determined that the mutation, Ivs10-1G→T, is a founder mutation in the Pakistani population. Conclusion: We identified 2 splice site mutations in the CDH3 gene leading to HJMD, further enriching our understanding of HJMD versus ectodermal dysplasia, ectrodactyly and macular dystrophy syndrome.
Clinical Management of Chronic Testicular Pain
Authors: Kumar Priyadarshi , Mehta Vivek , Nargund Vinod H.
Published: March 2010

Aim: To review the causes and principles and recent concepts in the management of testicular pain. Introduction: Chronic testicular pain is a common presenting symptom in genitourinary surgery. Due to increased awareness of testicular cancer and in men’s health more cases are likely to be referred. Material and Methods: A literature search was made for abstracts, original papers and review articles in the Cochrane Database, Medline and medical textbooks using the words ‘testicular pain’ and orchialgia to find the causes and mechanisms of testicular pain. The management and algorithm have been structured on evidence-based management strategies. Results: The management of chronic testicular pain remains essentially based on clinical assessment. In recent years there have been advances in the non-surgical management of testicular pain mainly because of the emergence of pain relief as a specialty. However, in some cases pain control is a problem and may ultimately conclude with orchiectomy. Conclusions: The management of chronic testicular pain includes a careful assessment of testicular and extratesticular causes. Relief of symptoms is not always possible and gaining an insight into the patient’s concerns and empathizing with their condition is paramount in helping them cope with their symptoms. Surgery should not be undertaken lightly for there is no guarantee that there will always be resolution of symptoms and the patient should be counseled accordingly.
A Nomogram Predicting Prostate Cancer-Specific Mortality after Radical Prostatectomy
Authors: Porter Christopher R. , Suardi Nazareno , Capitanio Umberto , Hutterer Georg C. , Kodama Koichi , Gibbons Robert P. , Correa Jr. Roy , Perrotte Paul , Montorsi Francesco , Karakiewicz Pierre I.
Published: March 2010

Objective: We describe a model capable of predicting prostate cancer (PCa)-specific mortality up to 20 years after a radical prostatectomy (RP), which can adjust the predictions according to disease-free interval. Patients and Methods: 752 patients were treated with RP for organ-confined PCa. Cox regression modeled the probability of PCa-specific mortality. The significance of the predictors was confirmed in competing risks analyses, which account for other-cause mortality. Results: The mean follow-up was 11.4 years. The 5-, 10-, 15- and 20-year actuarial rates of PCa-specific survival were 99.0, 95.5, 90.9 and 85.7%, respectively. RP Gleason sum (p < 0.001), pT stage (p = 0.007), adjuvant radiotherapy (p = 0.03) and age at RP (p = 0.004) represented independent predictors of PCa-specific mortality in the Cox regression model as well as in competing risks regression. Those variables, along with lymph node dissection status (p = 0.4), constituted the nomogram predictors. After 200 bootstrap resamples, the nomogram achieved 82.6, 83.8, 75.0 and 76.3% accuracy in predicting PCa-specific mortality at 5, 10, 15 and 20 years post-RP, respectively. Conclusions: At 20 years, roughly 20% of men treated with RP may succumb to PCa. The current nomogram helps to identify these individuals. Their follow-up or secondary therapies may be adjusted according to nomogram predictions.
Comparison of Gene Expression in LNCaP Prostate Cancer Cells after Treatment with Bicalutamide or 5-Alpha-Reductase Inhibitors
Authors: Bühler Patrick , Fischer Thomas , Wolf Philipp , Gierschner Dorothee , Schultze-Seemann Wolfgang , Wetterauer Ulrich , Elsässer-Beile Ursula
Published: March 2010

Introduction: Androgen deprivation is the preferred treatment for disseminated prostate cancer. However, it mostly leads to the development of incurable androgen-independent disease. The aim of the present study was to compare gene expression changes that occur after treatment with either the antiandrogen bicalutamide or the 5-α-reductase inhibitors finasteride (MK906) and MK386. Materials and Methods: LNCaP cells of low passages were treated with MK906 and MK386 at 5 µM each or with bicalutamide at 10 µM for 48 h. In these cultures we analyzed the expression of 22,500 transcripts on the Affymetrix Human U133+ 2.0 GeneChip platform. Gene expression was verified by real-time quantitative Taqman PCR. Results: Our studies revealed 312 differentially regulated genes upon bicalutamide treatment and 68 differentially regulated genes upon treatment with the 5-α-reductase inhibitors. There were 35 genes equally regulated by both drugs. This subset of genes included those with the highest fold change in both treatment groups. In the subset KlK2, TMPRSS2, TRGC2, PMEPA1 and TM4SF1 were downregulated, whereas EGR1, DDC and OPRK1 were upregulated. Conclusions: A cohort of interesting genes that are differentially expressed after androgen withdrawal could be found in this study. Investigation into these genes could contribute to a better understanding of antiandrogen treatment and development of androgen-independent prostate cancer.
Rare Etiology of Obstructive Uropathy: Pelvic Lipomatosis
Authors: Miglani Uday , Sinha Tapan , Gupta Sanjay K. , Doddamani Daresh , Sethi Gurwinder S. , Talwar Raghav , Agrawal Shalabh , Chandra Mahesh , Rana Yajvender P.S. , Harkar Sandeep
Published: March 2010

We present a case of a 32-year-old hypertensive and obese male who had bilateral obstructive uropathy, and who was diagnosed as having pelvic lipomatosis on the basis of clinicoradiological findings. Cystoscopy and biopsy revealed cystitis cystica. He was successfully managed with bilateral extravesical modified Lich-Gregoir ureteric reimplantation by intraperitoneal approach. At 5 months follow-up, the patient had normal serum creatinine and was clinically asymptomatic.
Natural Course of Lugol-Voiding Lesions in Patients with Superficial Esophageal Squamous Cell Carcinoma
Authors: Fukuhara Tatsuma , Hiyama Toru , Tanaka Shinji , Oka Shiro , Yoshihara Masaharu , Arihiro Koji , Chayama Kazuaki
Published: March 2010

Background: The presence of multiple Lugol-voiding lesions (LVLs) in the esophageal mucosa can indicate a high risk of esophageal squamous cell carcinoma (ESCC) as well as a diagnosis of ESCC and dysplasia. However, there have been no reports on the natural course of LVLs. Aim: This study aimed to clarify the characteristics and natural course of LVLs. Methods: Based on patients with ESCC who underwent endoscopic treatment, a retrospective study was conducted targeting 73 patients in whom the esophageal background mucosa was evaluated using Lugol staining and who were followed up for 12 months or more. LVLs were divided into groups A (none), B (several small), C (many small), and D (many irregular-shaped multiform). Results: The average follow-up period was 42.0 months. Groups A–D consisted of 13, 34, 21, and 5 patients, respectively. In group B, 3 of 34 (8.8%) patients advanced to group C. In group C, 2 of 21 (9.5%) patients advanced to group D. In total, 5 of all 73 (6.8%) patients advanced to a higher group. Conclusion: These data suggest that a risk of ESCC may obviously increase in only some of the patients by evaluation of LVLs.
Genetic Susceptibility to Type 2 Diabetes Is Associated with Reduced Prostate Cancer Risk
Authors: Pierce Brandon L. , Ahsan Habibul
Published: March 2010

Objective: To examine the collective effects of type 1 (T1D) and type 2 diabetes (T2D) risk alleles on prostate cancer (PCa) risk. Methods: Using data on 14 and 18 single nucleotide polymorphisms (SNPs) that effect T1D and T2D risk, respectively, we generated risk scores (a ‘risk allele count’ and a ‘genetic relative risk’) for both T1D and T2D for 1,171 non-Hispanic white, PSA-screened PCa cases and 1,101 matched controls from the Cancer Genetic Markers of Susceptibility study. Logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) for associations between the diabetes risk scores and PCa risk. Results: Both T2D risk scores, but neither T1D score, showed an inverse association with PCa (p < 0.01). These associations remained significant after excluding HNF1B SNP rs4430796 (a known PCa risk factor) from the analysis. The highest quartile of the T2D allele count (>20 risk alleles) was associated with reduced PCa risk (OR = 0.77; CI: 0.60–0.99) compared to the lowest category (<17 risk alleles). Conclusions: These results suggest that individuals with increased genetic susceptibility to T2D have decreased risk for PCa. This association is consistent with the observation that individuals with T2D are at decreased risk for PCa; however, data on T2D status was not available for this analysis.
Prenatal Lipopolysaccharide Reduces Social Behavior in Male Offspring
Authors: Kirsten Thiago B. , Taricano Marina , Maiorka Paulo C. , Palermo-Neto João , Bernardi Maria M.
Published: March 2010

Objective: This study investigated the relationship between maternal sickness behavior during pregnancy and offspring development and behavior. Methods: Pregnant Wistar rats were administered with lipopolysaccharide (LPS, 100 µg/kg, i.p.) on gestation day (GD) 9.5. Dams’ sickness behavior was analyzed, and at birth, offspring number and weight were evaluated. Male offspring was evaluated through physical development, play behavior, adult social interaction, plus maze studies and morphological analysis of the brain. Results: Results, with respect to the control group, showed that: (1) LPS decreased general activity, food intake, and weight gain in dams, but no pyrexia was observed following treatment; (2) LPS reduced litter size, but no alterations in physical development were observed; (3) LPS reduced play behavior parameters in baby rats; (4) LPS decreased adult social interaction; (5) no alterations were observed between groups on plus maze studies; (6) no differences were observed between groups on morphological analyses of the brain. Conclusion: These data reveal that LPS administered on GD 9.5 impaired male offspring’s social behavior in infancy and adulthood. These results may be related to an alteration in motivational states or/and increased anxiety.