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We theoretically investigate multifrequency cloak based on multishell by using transformation medium. As for each shell, we use the Maxwell–Garnett theory and the spectral representation theory to design the permittivity profile for the transverse magnetic wave. The plasma frequencies of the metals used in the inner (B) and outer (C) shells must satisfy ω1<ωpC<ω2<ωpB. In such case, incident electromagnetic wave of lower frequency ω1 will be distorted only by the outer shell C without entering the inner shell B to achieve invisibility. However, at the higher operating frequency ω2, the outer shell C is transparent by choosing the materials appropriately, and the incident electromagnetic wave will be distorted only by the inner shell B to achieve invisibility. So, the multishell cloak can work simultaneously on two different optical frequencies. Furthermore, we use the anisotropic differential effective dipole theory to evaluate the efficiency of the cylindrical cloak. [ABSTRACT FROM AUTHOR]

Biological cells can be treated as an inhomogeneous particle. In addition to biomaterials, inhomogeneous particles are also important in more traditional colloidal science. By using two energy methods that are based on Legendre polynomials and Green's function, respectively, we investigate the interaction between biological cells or colloidal particles in the presence of an external electric field, in an attempt to investigate the effect of inhomogeneity on crossover frequencies across which the interaction force changes from attraction to repulsion or vice versa. The predictions by the two methods agree with each other very well. It is shown that there exist two kinds of crossover frequencies ¿p, one from attraction to repulsion and the other from repulsion to attraction as external frequencies increase. The first ¿p strongly depends on the degree of inhomogeneity, while the second ¿p does not. This work has relevance to manipulation of biological cells or colloidal particles. [ABSTRACT FROM AUTHOR]

We present an effective medium theory based on the Maxwell-Garnett [J. C. Maxwell Garnett, Philos. Trans. R. Soc. London, Ser. A 203, 385 (1904); ibid. 205, 237 (1906)] and Bruggeman [D. A. G. Bruggeman, Ann. Phys. (Leipzig) 24, 636 (1935)] approximations, to investigate the effective mass density of binary and ternary liquid composites. Excellent agreement between our experiment and theory is shown. The results are well interpreted in terms of intermolecular interactions, which affect the miscibility between liquid components. Thus, it becomes possible to theoretically predict the effective mass density of liquid composites. [ABSTRACT FROM AUTHOR]

The local electric field has been derived analytically inside multilayer metallic films with weak nonlinearity, and hence the effective linear dielectric constant and third-order nonlinear susceptibility of the layered structures are calculated. As the number of layers increases, the comparison with the previous results of graded metallic films shows a gradual transition from sharp peaks to a broad continuous band. These results give further evidence of the emerging absorption band reported recently [J. P. Huang and K. W. Yu, Appl. Phys. Lett. 85, 94 (2004)]. Thus, multilayer metallic films can serve as optical materials with a giant enhancement of optical nonlinearity and a large figure of merit. [ABSTRACT FROM AUTHOR]

The effective nondegenerate four-wave mixing (NDFM) susceptibility of graded metallic films with weak nonlinearity is exactly derived by invoking the local-field effects. It is found that the presence of gradation in metallic films can yield a broad resonant plasmon band in the optical region, which results in a large enhancement in the NDFM response and thus a large figure of merit. [ABSTRACT FROM AUTHOR]

We apply a Langevin model to investigate the nonlinear ac responses of electro-magnetorheological (ERMR) fluids under the application of two crossed dc magnetic (z axis) and electric (x axis) fields and a probing ac sinusoidal magnetic field. We focus on the influence of the magnetic fields which can yield nonlinear behaviors inside the system due to the particles with a permanent magnetic dipole moment. Based on a perturbation approach, we extract the harmonics of the magnetic field and orientational magnetization analytically. To this end, we find that the harmonics are sensitive to the degree of anisotropy of the structure as well as the field frequency. Thus, it is possible to real-time-monitor the structure transformation of ERMR fluids by detecting the nonlinear ac responses. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

A theoretical study of the dielectrophoretic (DEP) spectrum of a pair of touching colloidal particles or biological cells in a host fluid under the application of a nonuniform alternating current (ac) electric field is presented. The main objective of this work is to investigate the correlation effects due to the presence of mutual polarization on the DEP spectrum. In particular, we employ the multiple image method to account for the effect of multiple images, and obtain an analytic expression for the DEP force. It is found that, at low frequencies, the DEP force can be enhanced (reduced) significantly for the longitudinal (transverse) field case due to the presence of multiple images. The numerical results can be well understood in the spectral representation theory. To first order in the dipole interaction, our results reduce to the established formula derived by an alternative method. Our approach demonstrates the importance of the correlation effects in ac electrokinetic phenomena of colloidal suspensions. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Anisotropic dielectric response occurs naturally due to the presence of gradation, like in functionally graded materials or graded biological cells. However, these materials with locally anisotropic dielectric responses can have macroscopically isotropic responses. In treating graded particles of anisotropic materials, traditional isotropic gradation methods need to be modified. In this work, we developed a first-principles approach, as well as an anisotropic differential effective dipole approximation, for calculating the dipole moment of these particles. To this end, the two methods are shown in excellent agreement. As a result, these approaches offer convenient and effective ways to investigate the dielectric properties and optical responses of graded spherical particles of anisotropic materials, as well as the electrokinetic phenomena of biological cells. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

When a sinusoidal (ac) field is applied to a suspension containing nonlinear dielectric particles, the electrical response will generally consist of ac fields at frequencies of the higher-order harmonics. The situation is further complicated by an intrinsic dielectric dispersion, which often occurs due to the surface conductivity or inhomogeneous structure of the particles. We develop a perturbation method to investigate the effect of intrinsic dielectric dispersion on the harmonics of local field as well as induced dipole moment. The results showed, for weak intrinsic dispersion strength, the ratio of the third to first harmonics of the induced dipole moment decreases as the frequency increases, which is qualitatively in agreement with experiment. However, for a strong dispersion strength, the harmonics ratio increases as the frequency increases. Moreover, an increase in the intrinsic relaxation time may increase the strength of the harmonics. [ABSTRACT FROM AUTHOR]

We have studied the multipole polarizability of a graded spherical particle in a nonuniform electric field, in which the conductivity can vary radially inside the particle. The main objective of this work is to access the effects of multipole interactions at small interparticle separations, which can be important in non-dilute suspensions of functionally graded materials. The nonuniform electric field arises either from that applied on the particle or from the local field of all other particles. We developed a differential effective multipole moment approximation (DEMMA) to compute the multipole moment of a graded spherical particle in a nonuniform external field. Moreover, we compare the DEMMA results with the exact results of the power-law graded profile and the agreement is excellent. The extension to anisotropic DEMMA will be studied in an Appendix. [ABSTRACT FROM AUTHOR]

Conductive organic polymers can be formulated with polymers that incorporate fine dispersed metallic particles. In this work, we present a general model for ferrogels which are chemically cross-linked polymer networks swollen with a ferrofluid. Our aim is to study the effect of the shape and/or material (conductivity) anisotropy on the effective electrical conductivity of the ferrogel in the presence of an external magnetic field. Our theory can reproduce the known results and provides a link between the particle properties and orientation distribution and the effective electrical conductivity. To this end, we find that material (conductivity) anisotropies are more important for yielding a high effective electrical conductivity than shape anisotropies, while magnetic fields can offer a correction. [ABSTRACT FROM AUTHOR]

Focuses on the development of a theory concerning the effective linear and nonlinear optical properties of composite media by considering the dielectric anisotropy of the nonlinear graded particles. Model of the effective linear dialectric constant; Application of the nonlinear anisotropic differential effective dipole approximation in a nonlinear metal-dielectric composite; Role of the presence of gradation in the radial dialectric constant in enhancing the optical nonlinearity.

We investigate the pressure effect on the eletrorotation (ER) spectrum of living cell suspensions by considering the particle shape effect. Based upon the spectral representation theory, we consider coated oblate spheroidal particles and present a theoretical study of ER spectrum. Analytic expressions for the characteristic frequency as well as the dispersion strength can be obtained, thus simplifying the fitting of experimental data. From the theoretical analysis, we find that the cell shape, coating as well as material parameters can change the ER spectrum. We demonstrate good agreement between our theoretical predictions and experimental data on human erythrocytes suspensions. [ABSTRACT FROM AUTHOR]

A hexagonal honeycomb magnetic tunneling junction array with 72 nm pitch and 30 nm MgO critical dimension was successfully fabricated on a 1× nm dynamic random access memory platform by using a mature dynamic random access memory patterning solution and ion beam etch. To our knowledge, both pitch size and critical dimension size are the world's smallest ones for industrial magnetic tunneling junction arrays. To obtain such a high density and small sized magnetic tunneling junction array, a cross self-aligned double patterning technique, a triple layer hard mask scheme, and an optimized ion beam etch condition were adopted. During the optimization of the ion beam etch process, the dependence of a magnetic tunneling junction pillar profile on ion beam etch parameters for a high density hexagonal magnetic tunneling junction array has also been systematically studied. The depth of oxide recess and the magnetic tunneling junction sidewall angle increased with the ion beam etch amount, while magnetic tunneling junction critical dimension and hard mask remainder thickness decreased with increasing ion beam etch amount. [ABSTRACT FROM AUTHOR]

We exploit theoretically nonlinear optical materials by graded multilayered colloidal crystals, whose basic layer is made of metallodielectric nanoparticles immersed periodically in a host fluid. In the crystals, either the volume fraction of nanoparticles or the dielectric constant of host fluid can vary gradually within layers. The electric field distribution can be shown to exhibit a peak in a certain layer, and that the position of the peak can change by tuning the incident angular frequency. Such a gradation-controlled electric field distribution serves as a physical mechanism for understanding the enhanced nonlinear optical responses with a broad plasmon band. [ABSTRACT FROM AUTHOR]

Based on nonlinear composite materials, we exploit theoretically a class of electrically tunable one-dimensional double-layer photonic crystals (PCs), namely, composite-dielectric and composite-composite PCs. For such PCs, extensive and precise tunability of photonic band gaps can be readily achieved by choosing appropriate pump ac or dc electric fields. [ABSTRACT FROM AUTHOR]

The authors theoretically exploit a class of nonlinear optical materials, which are made of single domain ferromagnetic nanoparticles coated by a nonmagnetic nanoshell with an intrinsic second-harmonic generation (SHG) susceptibility in a nonmagnetic host fluid. The SHG of such materials possess magnetic-field controllabilities, i.e., magnetic-field-controllable anisotropy, redshift, and enhancement, which are caused to appear by the shift of a resonant plasmon frequency due to the formation of the chains of the coated nanoparticles. [ABSTRACT FROM AUTHOR]

We theoretically exploit a class of colloidal-crystal-based nonlinear optical materials, which are made of graded metallodielectric nanoparticles suspended in a host fluid. Such materials can have both an enhancement and a redshift of optical nonlinearity, due to the gradation inside the nanoparticles as well as the lattice effects arising from the periodic structure. [ABSTRACT FROM AUTHOR]

We theoretically explore a type of bifunctional cloak possessing both electrical and thermal cloaking functionality. We employ a composite material to design the cloak shell. By using effective medium theory, the effective electrical and thermal conductivities of the composite material should meet the perfect conductivity profile calculated from the coordinate transformation approach. In the design, we choose nonspherical nanoparticles with appropriate electrical and thermal conductivities, shape aspects, and volume fractions. Furthermore, finite element simulations are performed to verify the properties of such bifunctional cloaks. [ABSTRACT FROM AUTHOR]

In this paper, we will propose a dielectrophoresis-based microchannel system. Based on numerical calculations and theoretical analysis, we investigate the dynamic behaviors of a microparticle in this system, in the presence of nonuniform electric fields generated by point microelectrodes. Good agreement is shown between them. It is found that the microelectrodes enable the system equilibrium to shift between monostable and bistable states. Further, we reveal that the microparticle can oscillate along the microchannel with a fixed period for the ideal case without a drag force, and that it can be located in either monostable or bistable states for the cases with drag forces. In view of these findings, we carefully address the possibility to design several microfluidic devices, namely, a microparticulate clock for timing, a binary random number generator for conducting stochastic calculations, and a flip-flop device for system memory. [ABSTRACT FROM AUTHOR]

Nanocrystalline diamond (NCD) films with thicknesses in the range of 0.12–1.5 μm were deposited on silicon substrates in CH4/H2/O2 gas mixtures by microwave plasma-enhanced chemical vapor deposition. The morphology and structure of these NCD films were analyzed by field-emission scanning electron microscopy, x-ray diffraction (XRD), and ultraviolet-Raman spectroscopy. The lower limit of the grain size in the NCD films was estimated to be 10 nm from the XRD measurements. These grains are embedded in a columnar-type structure. The elastic and mechanical properties of the NCD films were determined by measuring the dispersion of laser-induced surface acoustic waves. The densities were in the range of 3.41±0.11 g/cm3 and Young’s moduli varied between 674±34 and 953±48 GPa, depending on the growth time and deposition conditions. It is concluded that oxygen may have a significant positive effect on the elastic properties of NCD films. The growth rate decreases sharply for an oxygen content in the source gas in excess of about 4%. [ABSTRACT FROM AUTHOR]

We theoretically exploit a class of one-dimensional double-layer photonic crystals based on colloidal ferrofluids, which are made of ferromagnetic nanoparticles suspended in a carrier liquid. Depending on the magnetic-field-induced anisotropic property of the ferrofluid, precise controllability of the band gaps is demonstrated to be possible by applying an appropriate external magnetic field. [ABSTRACT FROM AUTHOR]

The two-dimensional material phosphorene has become a focus of the scientific community recently. On the basis of molecular dynamics simulations, we utilize phosphorene as a model material to study the behavior of water molecules confined by two phosphorene plates with nonflat surfaces. As the relative position of the two plates changes, the water molecules first stay in a melting process at 230 K and then exhibit a freezing process. The disparate variations of local confinements induced by the mismatch of the two plates are the key for understanding this extraordinary behavior of water. Our results imply that such nonflat surfaces could be an important factor for understanding or controlling the dynamics of water. The phenomena reported here may enrich the knowledge of water and inspire more applications of similar materials. [ABSTRACT FROM AUTHOR]

Since the thermal conduction equation has form invariance under coordinate transformation, one can design thermal metamaterials with novel functions by tailoring materials' thermal conductivities. In this work, we establish a different transformation theory, and propose a layered device with anisotropic thermal conductivities. The device is able to convert heat flux from parallel patterns into non-parallel patterns and vice versa. In the mean time, the heat flux pattern outside the device keeps undisturbed as if this device is absent. We perform finite-element simulations to confirm the converting behavior. This work paves a different way to manipulate the flow of heat at will. [ABSTRACT FROM AUTHOR]

Understanding the flow of liquidsand particularly water in nanochannelsis important for scientific and technological applications, such asfor filtration and drug delivery. Here we perform molecular dynamicssimulations to investigate the transfer of single-file water moleculesacross straight or nonstraight single-walled carbon nanotubes (SWCNTs).In contrast with the macroscopic scenario, the nonstraight nanostructurecan increase the water permeation. Remarkably, compared with the straightSWCNT, the nonstraight SWCNT with the minimal bending angle of 35°in the simulations can enhance the water transport up to 3.5 times.This enhancement mainly originates from the Lennard-Jones interactionbetween water molecules and nonstraight nanostructures. Our work offersan additional freedom to design high-flux nanochannels by choosingnonstraight nanostructures and provides an insight into water flowacross biological water nanochannels, which are often nonstraightsince they are composed of integral membrane proteins. [ABSTRACT FROM AUTHOR]

A correction to the article "Magneto-controlled nonlinear optical materials" that was published in the 2005 issue is presented.

Achieving a fast, unidirectional flow of single-file water molecules (UFSWM) across nanochannels is important for membrane-based water purification or seawater desalination. For this purpose, electro-osmosis methods are recognized as a very promising approach and have been extensively discussed in the literature. Utilizing molecular dynamics simulations, here we propose a design for pumping water molecules in a single-walled carbon nanotube in the presence of a linearly gradient electric (GE) field. Such a GE field is inspired by GE fields generated from charged ions located adjacent to biological membrane water nanochannels that can conduct water in and out of cells and can be experimentally achieved by using the charged tip of an atomic force microscope. As a result, the maximum speed of the UFSWM can be 1 or 2 orders of magnitude larger than that in a uniform electric (UE) field. Also, inverse transportation of water molecules does not exist in case of the GE field but can appear for the UE field. Thus, the GE field yields a much more efficient UFSWM than the UE field. The giant pumping ability as revealed is attributed to the nonzero net electrostatic force acting on each water molecule confined in the nanotube. These observations have significance for the design of nanoscale devices for readily achieving controllable UFSWM at high speed. [ABSTRACT FROM AUTHOR]

Objectives: Previous studies have reported immortalization and tumorigenicity of human mesenchymal stem cells (hMSCs) transduced with exogenous human telomerase reverse transcriptase (hTERT). We also have established a line of hMSCs transduced with hTERT (hTERT–hMSCs) and we have cultured these cells for 290 population doublings (PDs) during which they demonstrated a large proliferation potential but with no tumorigenicity. The aim of this study was to investigate the protein expression profile of hTERT–hMSCs with two-dimensional gel electrophoresis and peptide mass fingerprinting by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, to be able to analyse the effects of exogenous hTERT on protein expression in hMSCs. Materials and methods: We generated proteome maps of primary hMSCs and hTERT–hMSCs at PD 95 and PD 275. Results: A total of 1543 ± 145 protein spots in gels of primary MSCs at PD 12, 1611 ± 186 protein spots in gels of hTERT–hMSCs at PD 95 and 1451 ± 126 protein spots in gels of hTERT–hMSCs at 275 PD were detected. One hundred of these were successfully identified, including 20 which were differentially expressed. Conclusions: The results suggest that sustaining levels of prohibitin and p53 expression along with differential expression of proteins in hTERT–hMSCs provide an insight into lack of transforming activity of hTERT–hMSCs during cell proliferation. [ABSTRACT FROM AUTHOR]

By using a perturbation approach, we investigate dynamic effects on nonlinear alternating current (ac) responses in electrorheological (ER) fluids under an ac or a direct current electric field. We show that the dynamic effect due to a shear flow plays a significant role in the responses. Our results can be well interpreted in the dielectric dispersion spectral representation, and they offer a convenient method to determine the relaxation time and rotation velocity of ER particles by measuring the nonlinear ac responses. [ABSTRACT FROM AUTHOR]

Particle rotation leads to a steady-state which is different from the equilibrium state in the absence of rotational motion. The change of the polarization of the particle due to the rotational motion is called the dynamic electrorheological effect (DER). There are three cases to be considered: rotating particles in a dc field, particle rotation due to a rotating field and spontaneous rotation of particle in dc field (Quincke rotation). In the DER of rotating particles, the particle rotational motion generally reduces the interparticle force between the particles. The effect becomes pronounced when the frequency is on the order of the relaxation rate of the surface charges. In the electrorotation of particles, the mutual interaction between approaching particles will change the electrorotation spectrum significantly. The electrorotation spectrum depends strongly on the medium conductivity as well as the conductivity contrast between the particle and the medium. In the collective behaviors of Quincke rotors, the mutual interactions between the individual rotors lead to the assembly of chain-like structures which make an angle with the applied field. This has an implication of a new class of material. [ABSTRACT FROM AUTHOR]

When a suspension consisting of electric particles having nonlinear characteristics is subjected to a sinusoidal alternating current (ac) electric field, the electric response will generally consist of ac fields at frequencies of higher-order harmonics. We experimentally report on harmonic generation by erythrocytes subjected to an ac electric field. We find that both even and odd harmonics are sensitive to cell shapes, conductivities, field frequencies, and field magnitude. Theoretical analysis based on a phenomenological model yield predictions that are in excellent agreement with the experiments. Thus, it becomes possible to detect nonlinear characteristics, shapes, and conductivities of erythrocytes by measuring such ac responses. [ABSTRACT FROM AUTHOR]

An object exhibits the infrared thermogram of another object, which is called thermal illusion as extensively investigated in the field of thermal metamaterials. However, almost all the existing thermal illusion behaviors were theoretically designed by using unconventional thermal conductivities, which means that the conductivities must be anisotropic, graded, or even singular due to the analytical methods in use. This problem largely limits fabrications for applications. By suggesting two discretization steps, here we put forward a numerical method instead to design thermal illusion, for which unconventional conductivities are no longer needed. In the meantime, more importantly, we reveal different thermal illusion behaviors. By tailoring the joint effects of thermal conduction and convection, we design a thermal pixel of cuboidal shape. We show that the assembly of such pixels into different two-dimensional arrays could generate infrared thermograms of different objects, which is thus called the digital thermal metasurface. Also, the metasurface is reconfigurable, and it can apparently produce all the existing thermal illusion behaviors reported in the literature. Finally, we experimentally fabricate a prototype. This work opens a door for applying conventional thermal conductivities of commercially available materials to thermal illusion, and we expect it to stimulate more exciting developments in electromagnetic disguise and confrontation. [ABSTRACT FROM AUTHOR]

Thermal metamaterials have been applied to implement thermal phenomena, such as invisibility, illusion, and refraction. However, during the fabrication, they probably have complicated issues which are on account of the complicated structures. To get around this, here we put forward a single-particle structure. The theory helps to simplify the existing methods, which will undoubtedly contribute to the efficiency of fabrication. For clarity, we show the simulation and experimental results of thermal invisibility and illusion based on our proposed single-particle structural materials. Moreover, by tailoring the shape factor of the single particle appropriately, we can simultaneously realize thermal invisibility and illusion with only one device. The adjustable area fraction also indicates that these types of structural materials are highly adaptable. Such a single-particle device may have broad applications in misleading infrared detection. This work not only opens an avenue to design thermal materials based on single-particle structures but also holds for other physical fields like electrostatics, magnetostatics, and particle dynamics. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the safety and efficacy of ultrasound-guided high-intensity focused ultrasound (USgHIFU) for treating abdominal wall endometrioses (AWE).Design: A retrospective study.Setting: Department of Obstetrics and Gynaecology in China.Population: Patients with abdominal wall endometriosis.Methods: From August 2010 to April 2014, 32 patients with AWE were treated with USgHIFU in our hospital. USgHIFU treatment was performed with the Model JC-200 High Intensity Focused Ultrasound Tumor Therapeutic System. The symptom relief and the adverse effects were evaluated after USgHIFU ablation.Main Outcome Measures: USgHIFU as a new treatment option for patients with AWE.Results: Contrast-enhanced ultrasound showed that all lesions were successfully ablated with USgHIFU. The follow-up results showed that the average volume of AWE lesions at 6 months after USgHIFU was significantly smaller than that before treatment (2.80 ± 0.12 versus 1.33 ± 0.31 cm3 ). The pain scores at 6 months after treatment were significantly lower than those before treatment (6.80 ± 2.64 versus 1.80 ± 0.3). The non-perfused volume (indicative of successful ablation) was measured in all patients immediately after treatment, ranging from 0.9 to 2.1 cm3 (median: 1.6 cm3 ), and the fractional ablation ranged from 87% to 100% (median: 94%). Local oedema was observed in these patients, lasting for 1-3 days only. No severe complications occurred during the follow-up period.Conclusions: Based on our study, USgHIFU ablation is a safe and effective method for treating AWE.Tweetable Abstract: As a non-invasive treatment technique, HIFU could be used to treat abdominal wall endometriosis. [ABSTRACT FROM AUTHOR]

Y-chromosome-specific haplotypes (Y-haplotypes) constructed using single nucleotide polymorphisms (Y- SNPs) in the MSY (male-specific region of the Y-chromosome) are valuable in population genetic studies. But sequence variants in the yak MSY region have been poorly characterized so far. In this study, we screened a total of 16 Y-chromosome-specific gene segments from the ZFY, SRY, UTY, USP9Y, AMELY and OFD1Y genes to identify Y- SNPs in domestic yaks. Six novel Y- SNPs distributed in the USP9Y (g.223C>T), UTY19 (g.158A>C and g.169C>T), AMELY2 (g.261C>T), OFD1Y9 (g.165A>G) and SRY4 (g.104G>A) loci, which can define three Y-haplotypes ( YH1, YH2 and YH3) in yaks, were discovered. YH1 was the dominant and presumably most ancient haplotype based on the comparison of UTY19 locus with other bovid species. Interestingly, we found informative UTY19 markers (g.158A>C and g.169C>T) that can effectively distinguish the three yak Y-haplotypes. The nucleotide diversity was 1.7 × 10−4 ± 0.3 × 10−4, indicating rich Y-chromosome diversity in yaks. We identified two highly divergent lineages ( YH1 and YH2 vs. YH3) that share similar frequencies ( YH1 + YH2: 0.82-0.89, YH3: 0.11-0.18) among all three populations. In agreement with previous mt DNA studies, we supported the hypothesis that the two highly divergent lineages ( YH1 and YH2 vs. YH3) derived from a single gene pool, which can be explained by the reunion of at least two paternal populations with the divergent lineages already accumulated before domestication. We estimated a divergence time of 408 110 years between the two divergent lineages, which is consistent with the data from mitochondrial DNA in yaks. [ABSTRACT FROM AUTHOR]

To determine the genetic diversity and paternal origin of Chinese cattle, 302 males from 16 Chinese native cattle breeds as well as 30 Holstein males and four Burma males as controls were analysed using four Y- SNPs and two Y- STRs. In Chinese bulls, the taurine Y1 and Y2 haplogroups and indicine Y3 haplogroup were detected in seven, 172 and 123 individuals respectively, and these frequencies varied among the Chinese cattle breeds examined. Y2 dominates in northern China (91.4%), and Y3 dominates in southern China (90.8%). Central China is an admixture zone, although Y2 predominates overall (72.0%). The geographical distributions of the Y2 and Y3 haplogroup frequencies revealed a pattern of male indicine introgression from south to north China. The three Y haplogroups were further classified into one Y1 haplotype, five Y2 haplotypes and one Y3 haplotype in Chinese native bulls. Due to the interplay between taurine and indicine types, Chinese cattle represent an extensive reservoir of genetic diversity. The Y haplotype distribution of Chinese cattle exhibited a clear geographical structure, which is consistent with mt DNA, historical and geographical information. [ABSTRACT FROM AUTHOR]

Contrarian behavior is a kind of self-organization in complex adaptive systems (CASs). Here we report the existence of a transition point in a model resource-allocation CAS with contrarian behavior by using human experiments, computer simulations, and theoretical analysis. The resource ratio and system predictability serve as the tuning parameter and order parameter, respectively. The transition point helps to reveal the positive or negative role of contrarian behavior. This finding is in contrast to the common belief that contrarian behavior always has a positive role in resource allocation, say, stabilizing resource allocation by shrinking the redundancy or the lack of resources. It is further shown that resource allocation can be optimized at the transition point by adding an appropriate size of contrarians. This work is also expected to be of value to some other fields ranging from management and social science to ecology and evolution. [ABSTRACT FROM AUTHOR]

On the basis of molecular dynamics simulations, we investigate water permeation across a single-walled carbon nanotube (SWCNT) under the influence of four symmetrical half-rings, each having six LiF dipolar molecules. The flux remains almost fixed as the separation, R, between the rings and SWCNT is larger than 1.562 nm, but decreases significantly as 0.944 nm < R< 1.562 nm, and reaches zero as R< 0.944 nm. This nanochannel shows an excellent on−off gate that is both effectively resistant to dipole noises and sensitive to available signals. The finite element method reveals that the electrostatic field generated by LiF molecules plays a unique role in achieving the gating of the water SWCNT. Each water molecule tends to stay at the most stable state by moving to the location with the highest field strength in order to maintain its lowest electric energy. These findings may have biological implications because membrane water nanochannels made up of proteins accompanied with co-ions and counterions (due to ionization) share a similar single-file water chain inside the SWCNT with dipoles. The Appendix shows a possible link between the model system and a membrane water nanochannel with co-ions and counterions. Furthermore, our observations may have significance for the design of SWCNT-based nanoscale devices with dipolar molecules. [ABSTRACT FROM AUTHOR]

To understand the dynamic rheological behavior of polar molecular electrorheological (PMER) fluids, the shear stress and viscosity of the colloids are compared with the parameters of their lamellar structures which are obtained simultaneously with the rheological characteristics using an electrorheoscope. The results of the experiments and molecular dynamics simulation indicate that the shear stress is mainly contributed by the moving particle rings, and there is an inverse correlation between the width of the moving particle rings and the shear stress. [ABSTRACT FROM AUTHOR]

We report the prenatal imaging findings of a rare case of cephalothoracopagus janiceps disymmetros diagnosed at 28 weeks' gestation. Two-dimensional ultrasound and magnetic resonance imaging demonstrated janiceps conjoined female twins with a single fused cranial vault, duplicated cerebra, two faces, four eyeballs, a fused thorax, two hearts, two thoracic spines, eight limbs and polyhydramnios. Three-dimensional and power Doppler ultrasound established the definitive classification of cephalothoracopagus conjoined twins and displayed the shared circulation between the two separate hearts. [ABSTRACT FROM AUTHOR]

We develop two energy methods to investigate interparticle forces in a chain of three microparticles in an electric field, two of which are fixed and symmetrically located in the two opposite sides of the third free microparticle. We reveal that, if the free microparticle is laterally dragged and released, it can oscillate perpendicular to the line joining the centers of the two fixed microparticles, being in simple harmonic oscillation with a fixed period for small oscillation amplitudes. This work demonstrates that microparticles can be used to record time, which makes it possible to design a new class of microparticulate clocks. [ABSTRACT FROM AUTHOR]