Implementing the Deutsch-Jozsa algorithm with macroscopic ensembles

NASA Astrophysics Data System (ADS)

Semenenko, Henry; Byrnes, Tim

2016-05-01

Quantum computing implementations under consideration today typically deal with systems with microscopic degrees of freedom such as photons, ions, cold atoms, and superconducting circuits. The quantum information is stored typically in low-dimensional Hilbert spaces such as qubits, as quantum effects are strongest in such systems. It has, however, been demonstrated that quantum effects can be observed in mesoscopic and macroscopic systems, such as nanomechanical systems and gas ensembles. While few-qubit quantum information demonstrations have been performed with such macroscopic systems, a quantum algorithm showing exponential speedup over classical algorithms is yet to be shown. Here, we show that the Deutsch-Jozsa algorithm can be implemented with macroscopic ensembles. The encoding that we use avoids the detrimental effects of decoherence that normally plagues macroscopic implementations. We discuss two mapping procedures which can be chosen depending upon the constraints of the oracle and the experiment. Both methods have an exponential speedup over the classical case, and only require control of the ensembles at the level of the total spin of the ensembles. It is shown that both approaches reproduce the qubit Deutsch-Jozsa algorithm, and are robust under decoherence.

Active Polar Two-Fluid Macroscopic Dynamics

NASA Astrophysics Data System (ADS)

Pleiner, Harald; Svensek, Daniel; Brand, Helmut R.

2014-03-01

We study the dynamics of systems with a polar dynamic preferred direction. Examples include the pattern-forming growth of bacteria (in a solvent, shoals of fish (moving in water currents), flocks of birds and migrating insects (flying in windy air). Because the preferred direction only exists dynamically, but not statically, the macroscopic variable of choice is the macroscopic velocity associated with the motion of the active units. We derive the macroscopic equations for such a system and discuss novel static, reversible and irreversible cross-couplings connected to this second velocity. We find a normal mode structure quite different compared to the static descriptions, as well as linear couplings between (active) flow and e.g. densities and concentrations due to the genuine two-fluid transport derivatives. On the other hand, we get, quite similar to the static case, a direct linear relation between the stress tensor and the structure tensor. This prominent ``active'' term is responsible for many active effects, meaning that our approach can describe those effects as well. In addition, we also deal with explicitly chiral systems, which are important for many active systems. In particular, we find an active flow-induced heat current specific for the dynamic chiral polar order.

Probing coal architecture by magnetic resonance microscopy.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Botto, R. E.; Clifford, D. J.; Gregory, D. M.

1999-02-24

Time-resolved MRM investigations of a well-characterized suite of cross-linked polymers have yielded information on the nature of the solvent transport dynamics and mechanical relaxation of the networks. Network response parameters were then used to assess the macroscopic properties and cross-link densities of polymers with the degree of curing. This new approach is presently being developed to elucidate the complex macromolecular nature of coals and the variation with coal rank.

Evaluation of shielding parameters for heavy metal fluoride based tellurite-rich glasses for gamma ray shielding applications

NASA Astrophysics Data System (ADS)

Sayyed, M. I.; Lakshminarayana, G.; Kityk, I. V.; Mahdi, M. A.

2017-10-01

In this work, we have evaluated the γ-ray shielding parameters such as mass attenuation coefficient (μ/ρ), effective atomic number (Zeff), half value layer (HVL), mean free path (MFP) and exposure buildup factors (EBF) for heavy metal fluoride (PbF2) based tellurite-rich glasses. In addition, neutron total macroscopic cross sections (∑R) for these glasses were also calculated. The maximum value for μ/ρ, Zeff and ∑R was found for heavy metal (Bi2O3) oxide introduced glass. The results of the selected glasses have been compared, in terms of MFP with different glass systems. The shielding effectiveness of the selected glasses is found comparable or better than of common ones, which indicates that these glasses with suitable oxides could be developed for gamma ray shielding applications.

Thermal neutron macroscopic absorption cross section measurement (theory, experiment and results) for small environmental samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Czubek, J.A.; Drozdowicz, K.; Gabanska, B.

Czubek`s method of measurement of the thermal neutron macroscopic absorption cross section of small samples has been developed at the Henryk Niewodniczanski Institute of Nuclear Physics in Krakow, Poland. Theoretical principles of the method have been elaborated in the one-velocity diffusion approach in which the thermal neutron parameters used have been averaged over a modified Maxwellian. In consecutive measurements the investigated sample is enveloped in shells of a known moderator of varying thickness and irradiated with a pulsed beam of fast neutrons. The neutrons are slowed-down in the system and a die-away rate of escaping thermal neutrons is measured. Themore » decay constant vs. thickness of the moderator creates the experimental curve. The absorption cross section of the unknown sample is found from the intersection of this curve with the theoretical one. The theoretical curve is calculated for the case when the dynamic material buckling of the inner sample is zero. The method does not use any reference absorption standard and is independent of the transport cross section of the measured sample. The volume of the sample is form of fluid or crushed material is about 170 cm{sup 3}. The standard deviation for the measured mass absorption cross section of rock samples is in the range of 4 divided by 20% of the measured value and for brines is of the order of 0.5%.« less

Monolithic Hierarchical Fractal Assemblies of Silica Nanoparticles Cross-Linked with Polynorbornene via ROMP: A Structure-Property Correlation from Molecular to Bulk through Nano

DTIC Science & Technology

2012-08-23

are referred to as aerogels , and despite an impressive collection of attrcative macroscopic proporties, gragility has been the primary drawback to...applications. In that regard, polymer-cross-linked silica aerogels have emerged as strong lightweight nanostructured alternatives rendering new...applications unrelated to aerogels before, as in balistic protection, possible. However, the exact location of the polymer ion the elementary structure of

General multi-group macroscopic modeling for thermo-chemical non-equilibrium gas mixtures.

PubMed

Liu, Yen; Panesi, Marco; Sahai, Amal; Vinokur, Marcel

2015-04-07

This paper opens a new door to macroscopic modeling for thermal and chemical non-equilibrium. In a game-changing approach, we discard conventional theories and practices stemming from the separation of internal energy modes and the Landau-Teller relaxation equation. Instead, we solve the fundamental microscopic equations in their moment forms but seek only optimum representations for the microscopic state distribution function that provides converged and time accurate solutions for certain macroscopic quantities at all times. The modeling makes no ad hoc assumptions or simplifications at the microscopic level and includes all possible collisional and radiative processes; it therefore retains all non-equilibrium fluid physics. We formulate the thermal and chemical non-equilibrium macroscopic equations and rate coefficients in a coupled and unified fashion for gases undergoing completely general transitions. All collisional partners can have internal structures and can change their internal energy states after transitions. The model is based on the reconstruction of the state distribution function. The internal energy space is subdivided into multiple groups in order to better describe non-equilibrium state distributions. The logarithm of the distribution function in each group is expressed as a power series in internal energy based on the maximum entropy principle. The method of weighted residuals is applied to the microscopic equations to obtain macroscopic moment equations and rate coefficients succinctly to any order. The model's accuracy depends only on the assumed expression of the state distribution function and the number of groups used and can be self-checked for accuracy and convergence. We show that the macroscopic internal energy transfer, similar to mass and momentum transfers, occurs through nonlinear collisional processes and is not a simple relaxation process described by, e.g., the Landau-Teller equation. Unlike the classical vibrational energy relaxation model, which can only be applied to molecules, the new model is applicable to atoms, molecules, ions, and their mixtures. Numerical examples and model validations are carried out with two gas mixtures using the maximum entropy linear model: one mixture consists of nitrogen molecules undergoing internal excitation and dissociation and the other consists of nitrogen atoms undergoing internal excitation and ionization. Results show that the original hundreds to thousands of microscopic equations can be reduced to two macroscopic equations with almost perfect agreement for the total number density and total internal energy using only one or two groups. We also obtain good prediction of the microscopic state populations using 5-10 groups in the macroscopic equations.

A Multiscale Model for the Quasi-Static Thermo-Plastic Behavior of Highly Cross-Linked Glassy Polymers

DOE PAGES

Vu-Bac, N.; Bessa, M. A.; Rabczuk, Timon; ...

2015-09-10

In this paper, we present experimentally validated molecular dynamics predictions of the quasi- static yield and post-yield behavior for a highly cross-linked epoxy polymer under gen- eral stress states and for different temperatures. In addition, a hierarchical multiscale model is presented where the nano-scale simulations obtained from molecular dynamics were homogenized to a continuum thermoplastic constitutive model for the epoxy that can be used to describe the macroscopic behavior of the material. Three major conclusions were achieved: (1) the yield surfaces generated from the nano-scale model for different temperatures agree well with the paraboloid yield crite- rion, supporting previous macroscopicmore » experimental observations; (2) rescaling of the entire yield surfaces to the quasi-static case is possible by considering Argon’s theoretical predictions for pure compression of the polymer at absolute zero temperature; (3) nano- scale simulations can be used for an experimentally-free calibration of macroscopic con- tinuum models, opening new avenues for the design of materials and structures through multi-scale simulations that provide structure-property-performance relationships.« less

Neutron shielding behavior of thermoplastic natural rubber/boron carbide composites

NASA Astrophysics Data System (ADS)

Mat Zali, Nurazila; Yazid, Hafizal; Megat Ahmad, Megat Harun Al Rashid

2018-01-01

Many shielding materials have been designed against the harm of different types of radiation to the human body. Today, polymer-based lightweight composites have been chosen by the radiation protection industry. In the present study, thermoplastic natural rubber (TPNR) composites with different weight percent of boron carbide (B4C) fillers (0% to 30%) were fabricated as neutron shielding through melt blending method. Neutron attenuation properties of TPNR/B4C composites have been investigated. The macroscopic cross section (Σ), half value layer (HVL) and mean free path length (λ) of the composites have been calculated and the transmission curves have been plotted. The obtained results show that Σ, HVL and λ greatly depend on the B4C content. Addition of B4C fillers into TPNR matrix were found to enhance the macroscopic cross section values thus decrease the mean free path length (λ) and half value layer (HVL) of the composites. The transmission curves exhibited that the neutron transmission of the composites decreased with increasing shielding thickness. These results showed that TPNR/B4C composites have high potential for neutron shielding applications.

Examining the accuracy of visual diagnosis of tinea pedis and tinea unguium in aged care facilities.

PubMed

Goto, T; Nakagami, G; Takehara, K; Nakamura, T; Kawashima, M; Tsunemi, Y; Sanada, H

2017-04-02

The aim of this study was to examine the accuracy of visual diagnosis of tinea pedis (Athlete's foot) and tinea unguium (fungal nail infection), as well as to provide information on skin abnormalities that could help identify these diseases in aged care facilities (long-term care facilities (LTCFs) and nursing homes). A multicentre, cross-sectional observational study was conducted in a LTCF and two nursing homes. A dermatologist observed the skin abnormalities in the participants' interdigital and plantar areas, to screen for tinea pedis, and in the participants' toenails, to screen for tinea unguium. If abnormalities were noted, samples such as scales or toenails were collected and examined using direct microscopy. The accuracy of the macroscopic observation for each skin abnormality was examined. A total of 173 residents were recruited. The accuracy of clinical diagnosis using macroscopic observation was relatively low. The sensitivities and specificities for clinical diagnosis were 0.37 and 0.95 for tinea pedis in the interdigital areas, 0.47 and 0.94 for tinea pedis in the plantar areas, and 0.80 and 0.61 for tinea unguium in toenails, respectively. Scales in the plantar areas and discoloration of the toenails were more frequently observed in residents with tinea pedis and tinea unguium than in those without them. Several skin abnormalities were observed in the residents recruited in this study, but there was insufficient correlation with tinea pedis and tinea unguium to be used for screening.

Stress-enhanced gelation: a dynamic nonlinearity of elasticity.

PubMed

Yao, Norman Y; Broedersz, Chase P; Depken, Martin; Becker, Daniel J; Pollak, Martin R; Mackintosh, Frederick C; Weitz, David A

2013-01-04

A hallmark of biopolymer networks is their sensitivity to stress, reflected by pronounced nonlinear elastic stiffening. Here, we demonstrate a distinct dynamical nonlinearity in biopolymer networks consisting of filamentous actin cross-linked by α-actinin-4. Applied stress delays the onset of relaxation and flow, markedly enhancing gelation and extending the regime of solidlike behavior to much lower frequencies. We show that this macroscopic network response can be accounted for at the single molecule level by the increased binding affinity of the cross-linker under load, characteristic of catch-bond-like behavior.

Avoided-Level-Crossing Spectroscopy with Dressed Matter Waves

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eckardt, Andre; Holthaus, Martin

2008-12-12

We devise a method for probing resonances of macroscopic matter waves in shaken optical lattices by monitoring their response to slow parameter changes, and show that such resonances can be disabled by particular choices of the driving amplitude. The theoretical analysis of this scheme reveals far-reaching analogies between dressed atoms and time periodically forced matter waves.

Avoided-Level-Crossing Spectroscopy with Dressed Matter Waves

NASA Astrophysics Data System (ADS)

Eckardt, André; Holthaus, Martin

2008-12-01

We devise a method for probing resonances of macroscopic matter waves in shaken optical lattices by monitoring their response to slow parameter changes, and show that such resonances can be disabled by particular choices of the driving amplitude. The theoretical analysis of this scheme reveals far-reaching analogies between dressed atoms and time periodically forced matter waves.

On creating macroscopically identical granular systems with different numbers of particles

NASA Astrophysics Data System (ADS)

van der Meer, Devaraj; Rivas, Nicolas

2015-11-01

One of the fundamental differences between granular and molecular hydrodynamics is the enormous difference in the total number of constituents. The small number of particles implies that the role of fluctuations in granular dynamics is of paramount importance. To obtain more insight in these fluctuations, we investigate to what extent it is possible to create identical granular hydrodynamic states with different number of particles. A definition is given of macroscopically equivalent systems, and the dependency of the conservation equations on the particle size is studied. We show that, in certain cases, and by appropriately scaling the microscopic variables, we are able to compare systems with significantly different number of particles that present the same macroscopic phenomenology. We apply these scalings in simulations of a vertically vibrated system, namely the density inverted granular Leidenfrost state and its transition to a buoyancy-driven convective state.

Structural stability and electronic behaviors of Co1-xOsxSi and macroscopic magnetic susceptibilities of CoSi and OsSi: GGA-PBEsol, GW-approximation and QTAIM investigations

NASA Astrophysics Data System (ADS)

Bouafia, H.; Sahli, B.; Timaoui, M. A.; Djebour, B.; Hiadsi, S.; Abidri, B.

2018-02-01

The present work represents a theoretical investigation based on FP-(L)APW + lo method of structural properties, mechanical stability and electronic properties of Co1-xOsxSi as well as the macroscopic magnetic susceptibilities of CoSi and OsSi. The structural properties such as cell parameter, bulk modulus, internal parameters and total energy of non-magnetic NM, ferromagnetic FM and antiferromagnetic AFM phases were predicted by GGA-PBEsol semilocal functional. The obtained results for CoSi and OsSi are in good agreement with those found previously. The spin, orbital and total macroscopic magnetic susceptibilities of CoSi and OsSi have been estimated and confirmed that these compounds are diamagnetic. The total energy of the ferromagnetic phase of Co1-xOsxSi (with x = 0.25, 0.5 and 0.75) is the lowest indicating that they are ferromagnetic materials. The generalized stability criteria indicate that Co1-xOsxSi maintain their mechanical stabilities under a hydrostatic pressure less than 10 GPa. The electronic properties calculated by GW-approximation indicate that CoSi and Co1-xOsxSi (with x = 0.25, 0.50 and 0.75) are semimetals whereas OsSi is a semiconductor with a pseudo-direct band-gap. The topological analysis by QTAIM and the charge density plots indicate that the strong covalent character is predominant for Cosbnd Si, Ossbnd Si and Cosbnd Os bonds.

Macroscopic strain controlled ion current in an elastomeric microchannel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuo, Chin-Chang; Nguyen, Du; Buchsbaum, Steven

We report on the fabrication of an ultra-high aspect ratio ionically conductive single microchannel with tunable diameter from ≈ 20 μm to fully closed. The 4 mm-long channel is fabricated in a Polydimethylsiloxane (PDMS) mold and its cross-sectional area is controlled by applying macroscopic compressive strain to the mold in a direction perpendicular to the channel length. We investigated the ionic conduction properties of the channel. For a wide range of compressive strain up to ≈ 0.27, the strain dependence of the resistance is monotonic and fully reversible. For strain > 0.27, ionic conduction suddenly shuts off and the system becomes hystereticmore » (whereby a finite strain reduction is required to reopen the channel). Upon unloading, the original behavior is retrieved. This reversible behavior is observed over 200 compression cycles. The cross-sectional area of the channel can be inferred from the ion current measurement, as confirmed by a Nano-Computed Tomography investigation. We show that the cross-sectional area decreases monotonically with the applied compressive strain in the reversible range, in qualitative agreement with linear elasticity theory. We find that the shut-off strain is affected by the spatial extent of the applied strain, which provides additional tunability. Our tunable channel is well-suited for multiple applications in micro/nano-fluidic devices.« less

Macroscopically constrained Wang-Landau method for systems with multiple order parameters and its application to drawing complex phase diagrams

NASA Astrophysics Data System (ADS)

Chan, C. H.; Brown, G.; Rikvold, P. A.

2017-05-01

A generalized approach to Wang-Landau simulations, macroscopically constrained Wang-Landau, is proposed to simulate the density of states of a system with multiple macroscopic order parameters. The method breaks a multidimensional random-walk process in phase space into many separate, one-dimensional random-walk processes in well-defined subspaces. Each of these random walks is constrained to a different set of values of the macroscopic order parameters. When the multivariable density of states is obtained for one set of values of fieldlike model parameters, the density of states for any other values of these parameters can be obtained by a simple transformation of the total system energy. All thermodynamic quantities of the system can then be rapidly calculated at any point in the phase diagram. We demonstrate how to use the multivariable density of states to draw the phase diagram, as well as order-parameter probability distributions at specific phase points, for a model spin-crossover material: an antiferromagnetic Ising model with ferromagnetic long-range interactions. The fieldlike parameters in this model are an effective magnetic field and the strength of the long-range interaction.

Development of cross-resistance by Aspergillus fumigatus to clinical azoles following exposure to prochloraz, an agricultural azole

PubMed Central

2014-01-01

Background The purpose of this study was to unveil whether azole antifungals used in agriculture, similar to the clinical azoles used in humans, can evoke resistance among relevant human pathogens like Aspergillus fumigatus, an ubiquitous agent in nature. Additionally, cross-resistance with clinical azoles was investigated. Antifungal susceptibility testing of environmental and clinical isolates of A. fumigatus was performed according to the CLSI M38-A2 protocol. In vitro induction assays were conducted involving daily incubation of susceptible A. fumigatus isolates, at 35°C and 180 rpm, in fresh GYEP broth medium supplemented with Prochloraz (PCZ), a potent agricultural antifungal, for a period of 30 days. Minimal inhibitory concentrations (MIC) of PCZ and clinical azoles were monitored every ten days. In order to assess the stability of the developed MIC, the strains were afterwards sub-cultured for an additional 30 days in the absence of antifungal. Along the in vitro induction process, microscopic and macroscopic cultural observations were registered. Results MIC of PCZ increased 256 times after the initial exposure; cross-resistance to all tested clinical azoles was observed. The new MIC value of agricultural and of clinical azoles maintained stable in the absence of the selective PCZ pressure. PCZ exposure was also associated to morphological colony changes: macroscopically the colonies became mostly white, losing the typical pigmentation; microscopic examination revealed the absence of conidiation. Conclusions PCZ exposure induced Aspergillus fumigatus morphological changes and an evident increase of MIC value to PCZ as well as the development of cross-resistance with posaconazole, itraconazole and voriconazole. PMID:24920078

Bathed, Strained, Attenuated, Annihilated: Towards Quantum Optomechanics

NASA Astrophysics Data System (ADS)

Pepper, Brian Jeffrey

The field of optomechanics studies tiny devices that can be pushed mechanically by light. It is an extremely promising avenue towards tests of quantum mechanics on a macroscopic scale, by transferring quantum states of light to nano- or micromechanical objects. This dissertation concerns a long term research program to create quantum superpositions of a macroscopic mirror in an optomechanical cavity. This dissertation has two broad thrusts. The first focuses on microfabrication of a new type of device called optomechanical trampoline resonators, consisting of a small mirror on a cross-shaped tensed silicon nitride membrane. Devices have been fabricated with high mechanical and optical quality, including a 300 kHz device with quality factor 480,000, as well as a device of optical finesse 107,000. These devices are well into the sideband-resolved regime and suitable for optical cooling to the quantum ground state. One such device has been optically cooled to approximately 10 phonons. The second major thrust is theoretical. Creating a macroscopic superposition is a challenging problem, requiring optical cooling to the ground state, strong coupling, extremely high optical finesse and extremely low frequency. A realistic assessment of achievable parameters indicates that it is possible to achieve ground state cooling or strong coupling, but not both. This dissertation proposes a new technique using postselection to achieve macroscopic superpositions with only weak coupling. This relaxes some of the required parameters by orders of magnitude. Prospects for observing hypothetical novel decoherence mechanisms are also discussed.

CYCLOTRON-WAVE INSTABILITIES,

DTIC Science & Technology

Interactions of waves on electron streams or plasmas are studied for several geometric configurations of finite cross section in a finite magnetic...velocity parallel to the magnetic field. It is further assumed that either macroscopic neutrality exists or static spacecharge forces are negligible. For...the most part the quasi-static analysis is used. For the case of two drifting streams cyclotron waves act to giveinstabilities which are either

TEMPEST II--A NEUTRON THERMALIZATION CODE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shudde, R.H.; Dyer, J.

The TEMPEST II neutron thermalization code in Fortran for IBM 709 or 7090 calculates thermal neutron flux spectra based upon the Wigner-Wilkins equation, the Wilkins equation, or the Maxwellian distribution. When a neutron spectrum is obtained, TEMPEST II provides microscopic and macroscopic cross section averages over that spectrum. Equations used by the code and sample input and output data are given. (auth)

Free-standing 3D polyaniline-CNT/Ni-fiber hybrid electrodes for high-performance supercapacitors

NASA Astrophysics Data System (ADS)

Li, Yuan; Fang, Yuzhu; Liu, Hong; Wu, Xiaoming; Lu, Yong

2012-04-01

Free-standing 3D macroscopic polyaniline (PANi)-carbon nanotube (CNT)-nickel fiber hybrids have been developed, and they deliver high specific capacitance (725 F g-1 at 0.5 A g-1) and high energy density at high rates (~22 W h kg-1 at 2000 W kg-1, based on total electrode mass) with good cyclability.Free-standing 3D macroscopic polyaniline (PANi)-carbon nanotube (CNT)-nickel fiber hybrids have been developed, and they deliver high specific capacitance (725 F g-1 at 0.5 A g-1) and high energy density at high rates (~22 W h kg-1 at 2000 W kg-1, based on total electrode mass) with good cyclability. Electronic supplementary information (ESI) available: Experimental details on preparation, characterization, and electrochemical testing; Fig. S1-S8, Schemes S1 and S2. See DOI: 10.1039/c2nr30252g

An investigation into electromagnetic force models: differences in global and local effects demonstrated by selected problems

NASA Astrophysics Data System (ADS)

Reich, Felix A.; Rickert, Wilhelm; Müller, Wolfgang H.

2018-03-01

This study investigates the implications of various electromagnetic force models in macroscopic situations. There is an ongoing academic discussion which model is "correct," i.e., generally applicable. Often, gedankenexperiments with light waves or photons are used in order to motivate certain models. In this work, three problems with bodies at the macroscopic scale are used for computing theoretical model-dependent predictions. Two aspects are considered, total forces between bodies and local deformations. By comparing with experimental data, insight is gained regarding the applicability of the models. First, the total force between two cylindrical magnets is computed. Then a spherical magnetostriction problem is considered to show different deformation predictions. As a third example focusing on local deformations, a droplet of silicone oil in castor oil is considered, placed in a homogeneous electric field. By using experimental data, some conclusions are drawn and further work is motivated.

Macroscopic Violation of Three Cauchy-Schwarz Inequalities Using Correlated Light Beams From an Infra-Red Emitting Semiconductor Diode Array

NASA Technical Reports Server (NTRS)

Edwards, P. J.; Huang, X.; Li, Y. Q. (Editor); Wang, Y. Z. (Editor)

1996-01-01

We briefly review quantum mechanical and semi-classical descriptions of experiments which demonstrate the macroscopic violation of the three Cauchy-Schwarz inequalities: g(sup 2)(sub 11)(0) greater than or equal to 1; g(sup 2)(sub 11)(0) greater than or equal to g(sup 2)(sub 11)(t), (t approaches infinity); (the absolute value of g(sup 2)(sub 11)(0))(exp 2) less than or equal to g(sup 2)(sub 11)(0) g(sup 2)(sub 11)(0). Our measurements demonstrate the violation, at macroscopic intensities, of each of these inequalities. We show that their violation, although weak, can be demonstrated through photodetector current covariance measurements on correlated sub-Poissonian Poissonian, and super Poissonian light beams. Such beams are readily generated by a tandem array of infrared-emitting semiconductor junction diodes. Our measurements utilize an electrically coupled array of one or more infrared-emitting diodes, optically coupled to a detector array. The emitting array is operated in such a way as to generate highly correlated beams of variable photon Fano Factor. Because the measurements are made on time scales long compared with the first order coherence time and with detector areas large compared with the corresponding coherence areas, first order interference effects are negligible. The first and second inequalities are violated, as expected, when a sub-Poissonian light beam is split and the intensity fluctuations of the two split beams are measured by two photodetectors and subsequently cross-correlated. The third inequality is violated by bunched (as well as anti-bunched) beams of equal intensity provided the measured cross correlation coefficient exceeds (F - 1)/F, where F is the measured Fano Factor of each beam. We also investigate the violation for the case of unequal beams.

A new multigroup method for cross-sections that vary rapidly in energy

DOE PAGES

Haut, Terry Scot; Ahrens, Cory D.; Jonko, Alexandra; ...

2016-11-04

Here, we present a numerical method for solving the time-independent thermal radiative transfer (TRT) equation or the neutron transport (NT) equation when the opacity (cross-section) varies rapidly in frequency (energy) on the microscale ε; ε corresponds to the characteristic spacing between absorption lines or resonances, and is much smaller than the macroscopic frequency (energy) variation of interest. The approach is based on a rigorous homogenization of the TRT/NT equation in the frequency (energy) variable. Discretization of the homogenized TRT/NT equation results in a multigroup-type system, and can therefore be solved by standard methods.

Macroscopic shape change of melt-processed YBa{sub 2}Cu{sub 3}O{sub x-}Y{sub 2}BaCuO{sub 5} bulk superconductors.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Diko, P.; Goretta, K. C.; Energy Technology

A macroscopic change in the shape of five-domain melt-processed YBa{sub 2}Cu{sub 3}O{sub x}/Y{sub 2}BaCuO{sub 5} bulk superconductors is reported and explained. The change, a distortion from circular cross-section, is attributed to liquid transport from a slower growth front in an a-axis direction to a faster growth front in a c-axis direction at the edge between the a- and c-growth fronts, a phenomenon that we call the edge melt distribution (EMD) effect. Formation of bands of higher Y{sub 2}BaCuO{sub 5} particle density along the a/c growth boundaries, which nearly coincide with {l_brace}110{r_brace}-type planes, is explained by the EMD effect.

Macroscopic Magnetization Control by Symmetry Breaking of Photoinduced Spin Reorientation with Intense Terahertz Magnetic Near Field

NASA Astrophysics Data System (ADS)

Kurihara, Takayuki; Watanabe, Hiroshi; Nakajima, Makoto; Karube, Shutaro; Oto, Kenichi; Otani, YoshiChika; Suemoto, Tohru

2018-03-01

We exploit an intense terahertz magnetic near field combined with femtosecond laser excitation to break the symmetry of photoinduced spin reorientation paths in ErFeO3 . We succeed in aligning macroscopic magnetization reaching up to 80% of total magnetization in the sample to selectable orientations by adjusting the time delay between terahertz and optical pump pulses. The spin dynamics are well reproduced by equations of motion, including time-dependent magnetic potential. We show that the direction of the generated magnetization is determined by the transient direction of spin tilting and the magnetic field at the moment of photoexcitation.

Metrologically useful states of spin-1 Bose condensates with macroscopic magnetization

NASA Astrophysics Data System (ADS)

Kajtoch, Dariusz; Pawłowski, Krzysztof; Witkowska, Emilia

2018-02-01

We study theoretically the usefulness of spin-1 Bose condensates with macroscopic magnetization in a homogeneous magnetic field for quantum metrology. We demonstrate Heisenberg scaling of the quantum Fisher information for states in thermal equilibrium. The scaling applies to both antiferromagnetic and ferromagnetic interactions. The effect preserves as long as fluctuations of magnetization are sufficiently small. Scaling of the quantum Fisher information with the total particle number is derived within the mean-field approach in the zero-temperature limit and exactly in the high-magnetic-field limit for any temperature. The precision gain is intuitively explained owing to subtle features of the quasidistribution function in the phase space.

Drifting Diaphyses: Asymmetry in Diametric Growth and Adaptation Along the Humeral and Femoral Length.

PubMed

Maggiano, Isabel S; Maggiano, Corey M; Tiesler, Vera G; Chi-Keb, Julio R; Stout, Sam D

2015-10-01

This study quantifies regional histomorphological variation along the human humeral and femoral diaphysis in order to gain information on diaphyseal growth and modeling drift patterns. Three thin sections at 40, 50, and 60% bone length were prepared from a modern Mexican skeletal sample with known age and sex to give a longitudinal perspective on the drifting cortex (12 adults and juveniles total, 7 male and 5 female). Point-count techniques were applied across eight cross-sectional regions of interest using the starburst sampling pattern to quantify percent periosteal and endosteal primary lamellar bone at each diaphyseal level. The results of this study show a posterio-medial drift pattern in the humerus with a posterior rotational trend along the diaphysis. In the femur, we observed a consistent lateral to anteriolateral drift and an increase in primary lamellar bone area of both, periosteal and endosteal origin, towards the distal part of the diaphysis. These observations characterize drifting diaphyses in greater detail, raising important questions about how to resolve microscopic and macroscopic cross-sectional analysis towards a more complete understanding of bone growth and mechanical adaptation. Accounting for modeling drift has the potential to positively impact age and physical activity estimation, and explain some of the significant regional variation in bone histomorphology seen within (and between) bone cross-sections due to differing ages of tissue formation. More study is necessary, however, to discern between possible drift scenarios and characterize populational variation. © 2015 Wiley Periodicals, Inc.

Post traumatic Fat Embolism in Common Femoral Vein on CT.

PubMed

Healy, N; Billington, K; Sheehy, N

2015-01-01

Fat embolism syndrome usually occurs following trauma where fat globules from long bone fractures produce pulmonary, cerebral or cutaneous effects. This case illustrates the presence of macroscopic fat in the right common femoral vein secondary to a long bone fracture. This finding is rare but should be looked for on cross-sectional imaging to allow early, aggressive treatment of fat embolism syndrome.

Vortex cutting in superconductors

DOE PAGES

Glatz, A.; Vlasko-Vlasov, V. K.; Kwok, W. K.; ...

2016-08-09

Vortex cutting and reconnection is an intriguing and still-unsolved problem central to many areas of classical and quantum physics, including hydrodynamics, astrophysics, and superconductivity. Here, in this paper, we describe a comprehensive investigation of the crossing of magnetic vortices in superconductors using time dependent Ginsburg-Landau modeling. Within a macroscopic volume, we simulate initial magnetization of an anisotropic high temperature superconductor followed by subsequent remagnetization with perpendicular magnetic fields, creating the crossing of the initial and newly generated vortices. The time resolved evolution of vortex lines as they approach each other, contort, locally conjoin, and detach, elucidates the fine details ofmore » the vortex-crossing scenario under practical situations with many interacting vortices in the presence of weak pinning. Finally, our simulations also reveal left-handed helical vortex instabilities that accompany the remagnetization process and participate in the vortex crossing events.« less

Vortex cutting in superconductors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glatz, A.; Vlasko-Vlasov, V. K.; Kwok, W. K.

Vortex cutting and reconnection is an intriguing and still-unsolved problem central to many areas of classical and quantum physics, including hydrodynamics, astrophysics, and superconductivity. Here, in this paper, we describe a comprehensive investigation of the crossing of magnetic vortices in superconductors using time dependent Ginsburg-Landau modeling. Within a macroscopic volume, we simulate initial magnetization of an anisotropic high temperature superconductor followed by subsequent remagnetization with perpendicular magnetic fields, creating the crossing of the initial and newly generated vortices. The time resolved evolution of vortex lines as they approach each other, contort, locally conjoin, and detach, elucidates the fine details ofmore » the vortex-crossing scenario under practical situations with many interacting vortices in the presence of weak pinning. Finally, our simulations also reveal left-handed helical vortex instabilities that accompany the remagnetization process and participate in the vortex crossing events.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, Puqing; Lindsay, Lucas R.; Koh, Yee Kan

Despite recent progress in the first-principles calculations and measurements of phonon mean-free-paths (ℓ), contribution of low-energy phonons to heat conduction in silicon is still inconclusive, as exemplified by the discrepancies as large as 30% between different first-principles calculations. In this study, we investigate the contribution of low-energy phonons with ℓ>0.8 μm by accurately measuring the cross-plane thermal conductivity (Λ cross) of crystalline silicon films by time-domain thermoreflectance (TDTR), over a wide range of film thicknesses 1≤ h f ≤ 10 μm and temperatures 100 ≤ T ≤ 300 K. We employ a dual-frequency TDTR approach to improve the accuracy ofmore » our Λ cross measurements. We find from our Λ cross measurements that phonons with ℓ>0.8 μm contribute 53 W m -1 K -1 (37%) to heat conduction in natural Si at 300 K while phonons with ℓ>3 μm contribute 523 W m -1 K -1 (61%) at 100 K, >20% lower than first-principles predictions of 68 W m -1 K -1 (47%) and 717 W m -1 K -1 (76%), respectively. Using a relaxation time approximation (RTA) model, we demonstrate that macroscopic damping (e.g., Akhieser s damping) eliminates the contribution of phonons with mean-free-paths >20 μm at 300 K, which contributes 15 W m -1 K -1 (10%) to calculated heat conduction in Si. Thus, we propose that omission of the macroscopic damping for low-energy phonons in the first-principles calculations could be one of the possible explanations for the observed differences between our measurements and calculations. Finally, our work provides an important benchmark for future measurements and calculations of the distribution of phonon mean-free-paths in crystalline silicon.« less

Mechanical Strength Improvements of Carbon Nanotube Threads through Epoxy Cross-Linking

PubMed Central

Yu, Qingyue; Alvarez, Noe T.; Miller, Peter; Malik, Rachit; Haase, Mark R.; Schulz, Mark; Shanov, Vesselin; Zhu, Xinbao

2016-01-01

Individual Carbon Nanotubes (CNTs) have a great mechanical strength that needs to be transferred into macroscopic fiber assemblies. One approach to improve the mechanical strength of the CNT assemblies is by creating covalent bonding among their individual CNT building blocks. Chemical cross-linking of multiwall CNTs (MWCNTs) within the fiber has significantly improved the strength of MWCNT thread. Results reported in this work show that the cross-linked thread had a tensile strength six times greater than the strength of its control counterpart, a pristine MWCNT thread (1192 MPa and 194 MPa, respectively). Additionally, electrical conductivity changes were observed, revealing 2123.40 S·cm−1 for cross-linked thread, and 3984.26 S·cm−1 for pristine CNT thread. Characterization suggests that the obtained high tensile strength is due to the cross-linking reaction of amine groups from ethylenediamine plasma-functionalized CNT with the epoxy groups of the cross-linking agent, 4,4-methylenebis(N,N-diglycidylaniline). PMID:28787868

A Bottom-Up Approach to Understanding Protein Layer Formation at Solid-Liquid Interfaces

PubMed Central

Kastantin, Mark; Langdon, Blake B.; Schwartz, Daniel K.

2014-01-01

A common goal across different fields (e.g. separations, biosensors, biomaterials, pharmaceuticals) is to understand how protein behavior at solid-liquid interfaces is affected by environmental conditions. Temperature, pH, ionic strength, and the chemical and physical properties of the solid surface, among many factors, can control microscopic protein dynamics (e.g. adsorption, desorption, diffusion, aggregation) that contribute to macroscopic properties like time-dependent total protein surface coverage and protein structure. These relationships are typically studied through a top-down approach in which macroscopic observations are explained using analytical models that are based upon reasonable, but not universally true, simplifying assumptions about microscopic protein dynamics. Conclusions connecting microscopic dynamics to environmental factors can be heavily biased by potentially incorrect assumptions. In contrast, more complicated models avoid several of the common assumptions but require many parameters that have overlapping effects on predictions of macroscopic, average protein properties. Consequently, these models are poorly suited for the top-down approach. Because the sophistication incorporated into these models may ultimately prove essential to understanding interfacial protein behavior, this article proposes a bottom-up approach in which direct observations of microscopic protein dynamics specify parameters in complicated models, which then generate macroscopic predictions to compare with experiment. In this framework, single-molecule tracking has proven capable of making direct measurements of microscopic protein dynamics, but must be complemented by modeling to combine and extrapolate many independent microscopic observations to the macro-scale. The bottom-up approach is expected to better connect environmental factors to macroscopic protein behavior, thereby guiding rational choices that promote desirable protein behaviors. PMID:24484895

Finite volume solution for two-phase flow in a straight capillary

NASA Astrophysics Data System (ADS)

Yelkhovsky, Alexander; Pinczewski, W. Val

2018-04-01

The problem of two-phase flow in straight capillaries of polygonal cross section displays many of the dynamic characteristics of rapid interfacial motions associated with pore-scale displacements in porous media. Fluid inertia is known to be important in these displacements but is usually ignored in network models commonly used to predict macroscopic flow properties. This study presents a numerical model for two-phase flow which describes the spatial and temporal evolution of the interface between the fluids. The model is based on an averaged Navier-Stokes equation and is shown to be successful in predicting the complex dynamics of both capillary rise in round capillaries and imbibition along the corners of polygonal capillaries. The model can form the basis for more realistic network models which capture the effect of capillary, viscous, and inertial forces on pore-scale interfacial dynamics and consequent macroscopic flow properties.

Fast determination of three-dimensional fibril orientation of type-I collagen via macroscopic chirality

NASA Astrophysics Data System (ADS)

Zhuo, Guan-Yu; Chen, Mei-Yu; Yeh, Chao-Yuan; Guo, Chin-Lin; Kao, Fu-Jen

2017-01-01

Polarization-resolved second harmonic generation (SHG) microscopy is appealing for studying structural proteins and well-organized biophotonic nanostructures, due to its highly sensitized structural specificity. In recent years, it has been used to investigate the chiroptical effect, particularly SHG circular dichroism (SHG-CD) in biological tissues. Although SHG-CD attributed to macromolecular structures has been demonstrated, the corresponding quantitative analysis and interpretation on how SHG correlates with second-order susceptibility χ(2) under circularly polarized excitations remains unclear. In this study, we demonstrate a method based on macroscopic chirality to elucidate the correlation between SHG-CD and the orientation angle of the molecular structure. By exploiting this approach, three-dimensional (3D) molecular orientation of type-I collagen is revealed with only two cross polarized SHG images (i.e., interactions of left and right circular polarizations) without acquiring an image stack of varying polarization.

External and internal gelation of pectin solutions: microscopic dynamics versus macroscopic rheology

NASA Astrophysics Data System (ADS)

Secchi, E.; Munarin, F.; Alaimo, M. D.; Bosisio, S.; Buzzaccaro, S.; Ciccarella, G.; Vergaro, V.; Petrini, P.; Piazza, R.

2014-11-01

Pectin is a natural biopolymer that forms, in the presence of divalent cations, ionic-bound gels typifying a large class of biological gels stabilized by non-covalent cross-links. We investigate and compare the kinetics of formation and aging of pectin gels obtained either through external gelation via perfusion of free Ca2+ ions, or by internal gelation due to the supply of the same ions from the dissolution of CaCO3 nanoparticles. The microscopic dynamics obtained with photon correlation imaging, a novel optical technique that allows obtaining the microscopic dynamics of the sample while retaining the spatial resolution of imaging techniques, is contrasted with macroscopic rheological measurements at constant strain. Pectin gelation is found to display peculiar two-stage kinetics, highlighted by non-monotonic growth in time of both microscopic correlations and gel mechanical strength. These results are compared to those found for alginate, another biopolymer extensively used in food formulation.

Totally Asymmetric Limit for Models of Heat Conduction

NASA Astrophysics Data System (ADS)

De Carlo, Leonardo; Gabrielli, Davide

2017-08-01

We consider one dimensional weakly asymmetric boundary driven models of heat conduction. In the cases of a constant diffusion coefficient and of a quadratic mobility we compute the quasi-potential that is a non local functional obtained by the solution of a variational problem. This is done using the dynamic variational approach of the macroscopic fluctuation theory (Bertini et al. in Rev Mod Phys 87:593, 2015). The case of a concave mobility corresponds essentially to the exclusion model that has been discussed in Bertini et al. (J Stat Mech L11001, 2010; Pure Appl Math 64(5):649-696, 2011; Commun Math Phys 289(1):311-334, 2009) and Enaud and Derrida (J Stat Phys 114:537-562, 2004). We consider here the convex case that includes for example the Kipnis-Marchioro-Presutti (KMP) model and its dual (KMPd) (Kipnis et al. in J Stat Phys 27:6574, 1982). This extends to the weakly asymmetric regime the computations in Bertini et al. (J Stat Phys 121(5/6):843-885, 2005). We consider then, both microscopically and macroscopically, the limit of large externalfields. Microscopically we discuss some possible totally asymmetric limits of the KMP model. In one case the totally asymmetric dynamics has a product invariant measure. Another possible limit dynamics has instead a non trivial invariant measure for which we give a duality representation. Macroscopically we show that the quasi-potentials of KMP and KMPd, which are non local for any value of the external field, become local in the limit. Moreover the dependence on one of the external reservoirs disappears. For models having strictly positive quadratic mobilities we obtain instead in the limit a non local functional having a structure similar to the one of the boundary driven asymmetric exclusion process.

Failure Analysis on Tail Rotor Teeter Pivot Bolt on a Helicopter

NASA Astrophysics Data System (ADS)

Qiang, WANG; Zi-long, DONG

2018-03-01

Tail rotor teeter pivot bolt of a helicopter fractured when in one flight. Failure analysis on the bolt was finished in laboratory. Macroscopic observation of the tailor rotor teeter pivot bolt, macro and microscopic inspection on the fracture surface of the bolt was carried out. Chemical components and metallurgical structure was also carried out. Experiment results showed that fracture mode of the tail rotor teeter pivot bolt is fatigue fracture. Fatigue area is over 80% of the total fracture surface, obvious fatigue band characteristics can be found at the fracture face. According to the results were analyzed from the macroscopic and microcosmic aspects, fracture reasons of the tail rotor teeter pivot bolt were analyzed in detail

Missing defects? A comparison of microscopic and macroscopic approaches to identifying linear enamel hypoplasia.

PubMed

Hassett, Brenna R

2014-03-01

Linear enamel hypoplasia (LEH), the presence of linear defects of dental enamel formed during periods of growth disruption, is frequently analyzed in physical anthropology as evidence for childhood health in the past. However, a wide variety of methods for identifying and interpreting these defects in archaeological remains exists, preventing easy cross-comparison of results from disparate studies. This article compares a standard approach to identifying LEH using the naked eye to the evidence of growth disruption observed microscopically from the enamel surface. This comparison demonstrates that what is interpreted as evidence of growth disruption microscopically is not uniformly identified with the naked eye, and provides a reference for the level of consistency between the number and timing of defects identified using microscopic versus macroscopic approaches. This is done for different tooth types using a large sample of unworn permanent teeth drawn from several post-medieval London burial assemblages. The resulting schematic diagrams showing where macroscopic methods achieve more or less similar results to microscopic methods are presented here and clearly demonstrate that "naked-eye" methods of identifying growth disruptions do not identify LEH as often as microscopic methods in areas where perikymata are more densely packed. Copyright © 2013 Wiley Periodicals, Inc.

Iatrogenic Bone and Soft Tissue Trauma in Robotic-Arm Assisted Total Knee Arthroplasty Compared With Conventional Jig-Based Total Knee Arthroplasty: A Prospective Cohort Study and Validation of a New Classification System.

PubMed

Kayani, Babar; Konan, Sujith; Pietrzak, Jurek R T; Haddad, Fares S

2018-03-27

The objective of this study was to compare macroscopic bone and soft tissue injury between robotic-arm assisted total knee arthroplasty (RA-TKA) and conventional jig-based total knee arthroplasty (CJ-TKA) and create a validated classification system for reporting iatrogenic bone and periarticular soft tissue injury after TKA. This study included 30 consecutive CJ-TKAs followed by 30 consecutive RA-TKAs performed by a single surgeon. Intraoperative photographs of the femur, tibia, and periarticular soft tissues were taken before implantation of prostheses. Using these outcomes, the macroscopic soft tissue injury (MASTI) classification system was developed to grade iatrogenic bone and soft tissue injuries. Interobserver and Intraobserver validity of the proposed classification system was assessed. Patients undergoing RA-TKA had reduced medial soft tissue injury in both passively correctible (P < .05) and noncorrectible varus deformities (P < .05); more pristine femoral (P < .05) and tibial (P < .05) bone resection cuts; and improved MASTI scores compared to CJ-TKA (P < .05). There was high interobserver (intraclass correlation coefficient 0.92 [95% confidence interval: 0.88-0.96], P < .05) and intraobserver agreement (intraclass correlation coefficient 0.94 [95% confidence interval: 0.92-0.97], P < .05) of the proposed MASTI classification system. There is reduced bone and periarticular soft tissue injury in patients undergoing RA-TKA compared to CJ-TKA. The proposed MASTI classification system is a reproducible grading scheme for describing iatrogenic bone and soft tissue injury in TKA. RA-TKA is associated with reduced bone and soft tissue injury compared with conventional jig-based TKA. The proposed MASTI classification may facilitate further research correlating macroscopic soft tissue injury during TKA to long-term clinical and functional outcomes. Copyright © 2018 Elsevier Inc. All rights reserved.

Self-Consistent Field Lattice Model for Polymer Networks.

PubMed

Tito, Nicholas B; Storm, Cornelis; Ellenbroek, Wouter G

2017-12-26

A lattice model based on polymer self-consistent field theory is developed to predict the equilibrium statistics of arbitrary polymer networks. For a given network topology, our approach uses moment propagators on a lattice to self-consistently construct the ensemble of polymer conformations and cross-link spatial probability distributions. Remarkably, the calculation can be performed "in the dark", without any prior knowledge on preferred chain conformations or cross-link positions. Numerical results from the model for a test network exhibit close agreement with molecular dynamics simulations, including when the network is strongly sheared. Our model captures nonaffine deformation, mean-field monomer interactions, cross-link fluctuations, and finite extensibility of chains, yielding predictions that differ markedly from classical rubber elasticity theory for polymer networks. By examining polymer networks with different degrees of interconnectivity, we gain insight into cross-link entropy, an important quantity in the macroscopic behavior of gels and self-healing materials as they are deformed.

[Macroscopic evaluation of the oral mucosa and analysis of salivary pH in patients with anorexia nervosa].

PubMed

Paszyńska, Elzbieta; Słopień, Agnieszka; Slebioda, Zuzanna S; Dyszkiewicz-Konwińska, Marta; Weglarz, Monika; Rajewski, Andrzej

2014-01-01

The aim of the study was to evaluate the status of the oral mucosa, to assess the prevalence of Candida in the oral cavity and to analyze the pH values of total saliva in patients with anorexia nervosa (AN) in comparison to the general population. A controlled clinical trial was designed for two, age-matched, female groups: patients with AN (Group A, n=31) and healthy women (Group 0, n = 40). Total saliva was collected at rest and after stimulation by chewing paraffin wax. Salivary pH was measured and macroscopic evaluation of the oral mucosa was performed with a qualitative and quantitative mycological analysis. The smear layer was collected from three different areas in the oral cavity. Selected Candida broths were used for incubation. Changes in the macroscopic structure of the oral mucosa due to multifactorial etiologies were observed. The prevalence of Candida in patients with AN was comparable to that in the general population. Salivary pH values were significantly lower in the AN patients than in the control group. The incidence of pathological changes in the oral mucosa is associated with the loss of the salivary protective barrier. This is shown by the significant reduction in the pH values of stimulated and non-stimulated saliva of the AN patients. In these patients, the monitoring of salivary parameters such as salivary flow rate and pH is indicated, and a regular dental checkup, together with soft tissue evaluation, is advised.

Thermal conductivity and dielectric functions of alkali chloride XCl (X = Li, Na, K and Rb): a first-principles study

NASA Astrophysics Data System (ADS)

Xu, M.; Yang, J. Y.; Liu, L. H.

2016-07-01

The macroscopic physical properties of solids are fundamentally determined by the interactions among microscopic electrons, phonons and photons. In this work, the thermal conductivity and infrared-visible-ultraviolet dielectric functions of alkali chlorides and their temperature dependence are fully investigated at the atomic level, seeking to unveil the microscopic quantum interactions beneath the macroscopic properties. The microscopic phonon-phonon interaction dominates the thermal conductivity which can be investigated by the anharmonic lattice dynamics in combination with Peierls-Boltzmann transport equation. The photon-phonon and electron-photon interaction intrinsically induce the infrared and visible-ultraviolet dielectric functions, respectively, and such microscopic processes can be simulated by first-principles molecular dynamics without empirical parameters. The temperature influence on dielectric functions can be effectively included by choosing the thermally equilibrated configurations as the basic input to calculate the total dipole moment and electronic band structure. The overall agreement between first-principles simulations and literature experiments enables us to interpret the macroscopic thermal conductivity and dielectric functions of solids in a comprehensive way.

Cross sectional epidemiological investigation on the prevalence of gastrointestinal helminths in free range chickens in Narsingdi district, Bangladesh.

PubMed

Ferdushy, Tania; Hasan, Mohammed Tabaruk; Golam Kadir, A K M

2016-09-01

Rural poultry production in Bangladesh is mainly based on the free range or backyard poultry production system. This backyard poultry plays a vital tool for poverty alleviation as well as for empowerment of poor women of this country. However, this production system has disadvantage of susceptibility to many diseases including higher burden of parasitic infection. Therefore this cross sectional epidemiological investigation was done to determine the prevalence and distribution of gastrointestinal helminths in Narsingdi district, Bangladesh. To conduct this study a total of 150 chickens from three different villages of Narsingdi district, Bangladesh (50 chickens per village) were collected by random sampling method and killed by cervical disarticulation. Thereafter, all the chickens were necropsied and gastrointestinal tracts were examined macroscopically for the presence helminth infection. In total two nematode (Ascaridia galli, Heterakis gallinarum,) and one cestode (Raillietina spp.) were identified by post mortem examination. Raillietina spp. was detected as the most prevalent helminth species (86-92 %) followed by A. galli (70-86 %), and H. gallinarum (70-76 %) in studied villages. In some chickens petechial hemorrhage were observed in the small intestinal wall which was associated with the A. galli infection and for some birds white tiny nodules were detected in case of H. gallinarum infection. No significant difference in parasite prevalence was observed between male and female bird as well as among three studied villages (P > 0.05). We observed that most of chickens were infected with more than one species of parasites. This finding suggests that the poultry production system in rural areas of Bangladesh and the environmental conditions are very favourable for the transmission and persistence of the parasite species in rural areas of Bangladesh.

Dermatological Feasibility of Multimodal Facial Color Imaging Modality for Cross-Evaluation of Facial Actinic Keratosis

PubMed Central

Bae, Youngwoo; Son, Taeyoon; Nelson, J. Stuart; Kim, Jae-Hong; Choi, Eung Ho; Jung, Byungjo

2010-01-01

Background/Purpose Digital color image analysis is currently considered as a routine procedure in dermatology. In our previous study, a multimodal facial color imaging modality (MFCIM), which provides a conventional, parallel- and cross-polarization, and fluorescent color image, was introduced for objective evaluation of various facial skin lesions. This study introduces a commercial version of MFCIM, DermaVision-PRO, for routine clinical use in dermatology and demonstrates its dermatological feasibility for cross-evaluation of skin lesions. Methods/Results Sample images of subjects with actinic keratosis or non-melanoma skin cancers were obtained at four different imaging modes. Various image analysis methods were applied to cross-evaluate the skin lesion and, finally, extract valuable diagnostic information. DermaVision-PRO is potentially a useful tool as an objective macroscopic imaging modality for quick prescreening and cross-evaluation of facial skin lesions. Conclusion DermaVision-PRO may be utilized as a useful tool for cross-evaluation of widely distributed facial skin lesions and an efficient database management of patient information. PMID:20923462

Nematic elastomers: from a microscopic model to macroscopic elasticity theory.

PubMed

Xing, Xiangjun; Pfahl, Stephan; Mukhopadhyay, Swagatam; Goldbart, Paul M; Zippelius, Annette

2008-05-01

A Landau theory is constructed for the gelation transition in cross-linked polymer systems possessing spontaneous nematic ordering, based on symmetry principles and the concept of an order parameter for the amorphous solid state. This theory is substantiated with help of a simple microscopic model of cross-linked dimers. Minimization of the Landau free energy in the presence of nematic order yields the neoclassical theory of the elasticity of nematic elastomers and, in the isotropic limit, the classical theory of isotropic elasticity. These phenomenological theories of elasticity are thereby derived from a microscopic model, and it is furthermore demonstrated that they are universal mean-field descriptions of the elasticity for all chemical gels and vulcanized media.

Transrectal implantation and stability of gold markers in prostate bed for salvage radiotherapy of macroscopic recurrences.

PubMed

Shakir, Shakir I; Udrescu, Corina; Enachescu, Ciprian; Rouviere, Olivier; Arion, Simona; Caraivan, Ionela; Chapet, Olivier

2016-11-01

The objective of the study was to verify the stability of gold markers in the prostatic bed (PB) during salvage radiotherapy. Seven patients, diagnosed with a macroscopic nodule visible on MRI, underwent targeted MRI-guided biopsies. Three gold markers were implanted into the PB close to the relapsing nodule for CT/MRI fusion. A dose of 60Gy was delivered using IMRT to the PB followed by a dose escalation up to 72Gy to the macroscopic nodule. Daily anterior and left-lateral kV-images were acquired for repositioning. The coordinates of the center of each marker were measured on the two kV-images. The distance variations (Dvar) of the markers in the first session and the subsequent ones were compared. No marker was lost during treatment. The average distance between markers was 7.8mm. The average Dvar was 0.8mm, in absolute value. A total of 380/528 (72%) Dvar were ⩽1mm. A Dvar greater than 2mm was observed in 5.7% of measurements, with a maximum value of 4.8mm. Despite the absence of the prostate, the implantation of gold markers in the PB remains feasible, with Dvar often less than 2mm, and could be used to develop new approaches of salvage focal radiotherapy on the macroscopic relapse after prostatectomy. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Role of low-energy phonons with mean-free-paths >0.8 μm in heat conduction in silicon

DOE PAGES

Jiang, Puqing; Lindsay, Lucas R.; Koh, Yee Kan

2016-06-30

Despite recent progress in the first-principles calculations and measurements of phonon mean-free-paths (ℓ), contribution of low-energy phonons to heat conduction in silicon is still inconclusive, as exemplified by the discrepancies as large as 30% between different first-principles calculations. In this study, we investigate the contribution of low-energy phonons with ℓ>0.8 μm by accurately measuring the cross-plane thermal conductivity (Λ cross) of crystalline silicon films by time-domain thermoreflectance (TDTR), over a wide range of film thicknesses 1≤ h f ≤ 10 μm and temperatures 100 ≤ T ≤ 300 K. We employ a dual-frequency TDTR approach to improve the accuracy ofmore » our Λ cross measurements. We find from our Λ cross measurements that phonons with ℓ>0.8 μm contribute 53 W m -1 K -1 (37%) to heat conduction in natural Si at 300 K while phonons with ℓ>3 μm contribute 523 W m -1 K -1 (61%) at 100 K, >20% lower than first-principles predictions of 68 W m -1 K -1 (47%) and 717 W m -1 K -1 (76%), respectively. Using a relaxation time approximation (RTA) model, we demonstrate that macroscopic damping (e.g., Akhieser s damping) eliminates the contribution of phonons with mean-free-paths >20 μm at 300 K, which contributes 15 W m -1 K -1 (10%) to calculated heat conduction in Si. Thus, we propose that omission of the macroscopic damping for low-energy phonons in the first-principles calculations could be one of the possible explanations for the observed differences between our measurements and calculations. Finally, our work provides an important benchmark for future measurements and calculations of the distribution of phonon mean-free-paths in crystalline silicon.« less

Bose-Einstein condensation of light: general theory.

PubMed

Sob'yanin, Denis Nikolaevich

2013-08-01

A theory of Bose-Einstein condensation of light in a dye-filled optical microcavity is presented. The theory is based on the hierarchical maximum entropy principle and allows one to investigate the fluctuating behavior of the photon gas in the microcavity for all numbers of photons, dye molecules, and excitations at all temperatures, including the whole critical region. The master equation describing the interaction between photons and dye molecules in the microcavity is derived and the equivalence between the hierarchical maximum entropy principle and the master equation approach is shown. The cases of a fixed mean total photon number and a fixed total excitation number are considered, and a much sharper, nonparabolic onset of a macroscopic Bose-Einstein condensation of light in the latter case is demonstrated. The theory does not use the grand canonical approximation, takes into account the photon polarization degeneracy, and exactly describes the microscopic, mesoscopic, and macroscopic Bose-Einstein condensation of light. Under certain conditions, it predicts sub-Poissonian statistics of the photon condensate and the polarized photon condensate, and a universal relation takes place between the degrees of second-order coherence for these condensates. In the macroscopic case, there appear a sharp jump in the degrees of second-order coherence, a sharp jump and kink in the reduced standard deviations of the fluctuating numbers of photons in the polarized and whole condensates, and a sharp peak, a cusp, of the Mandel parameter for the whole condensate in the critical region. The possibility of nonclassical light generation in the microcavity with the photon Bose-Einstein condensate is predicted.

Analysis of the total kinetic energy of fission fragments with the Langevin equation

NASA Astrophysics Data System (ADS)

Usang, M. D.; Ivanyuk, F. A.; Ishizuka, C.; Chiba, S.

2017-12-01

We analyzed the total kinetic energy (TKE) of fission fragments with three-dimensional Langevin calculations for a series of actinides and Fm isotopes at various excitation energies. This allowed us to establish systematic trends of TKE with Z2/A1 /3 of the fissioning system and as a function of excitation energy. In the mass-energy distributions of fission fragments we see the contributions from the standard, super-long, and super-short (in the case of 258Fm) fission modes. For the fission fragments mass distribution of 258Fm we obtained a single peak mass distribution. The decomposition of TKE into the prescission kinetic energy and Coulomb repulsion showed that decrease of TKE with growing excitation energy is accompanied by a decrease of prescission kinetic energy. It was also found that transport coefficients (friction and inertia tensors) calculated by a microscopic model and by macroscopic models give drastically different behaviors of TKE as a function of excitation energy. The results obtained with microscopic transport coefficients are much closer to experimental data than those calculated with macroscopic ones.

A topological extension of GR: Black holes induce dark energy

NASA Astrophysics Data System (ADS)

Spaans, M.

2013-02-01

A topological extension of general relativity is presented. The superposition principle of quantum mechanics, as formulated by the Feynman path integral, is taken as a starting point. It is argued that the trajectories that enter this path integral are distinct and thus that space-time topology is multiply connected. Specifically, space-time at the Planck scale consists of a lattice of three-tori that facilitates many distinct paths for particles to travel along. To add gravity, mini black holes are attached to this lattice. These mini black holes represent Wheeler's quantum foam and result from the fact that GR is not conformally invariant. The number of such mini black holes in any time-slice through four-space is found to be equal to the number of macroscopic (so long-lived) black holes in the entire universe. This connection, by which macroscopic black holes induce mini black holes, is a topological expression of Mach's principle. The proposed topological extension of GR can be tested because, if correct, the dark energy density of the universe should be proportional the total number of macroscopic black holes in the universe at any time. This prediction, although strange, agrees with current astrophysical observations.

The utility of routine histological examination of gunshot wounds.

PubMed

Perez, Danielo B; Molina, D Kimberley

2012-09-01

Determining the range of fire is a crucial part of a forensic examination of gunshot wound victims. Traditionally, this has been accomplished by noting the gross appearance of soot or powder around the wound. This study was undertaken to determine the utility of routine histological examination of gunshot wounds as related to range-of-fire determination. A prospective study was performed, and a total of 69 gunshot wounds were examined both macroscopically and microscopically. Of the 45 entrance wounds examined, there was 100% concordance between macroscopic and microscopic analysis for the close-range wounds and 67% concordance for the distant wounds, with 33% of these wounds showing no evidence of soot or powder grossly but where residue was seen microscopically. In addition, 21% of the exit wounds examined showed microscopic evidence of soot/powder residues when none were visible macroscopically. As described in previous studies, it can be assumed that the bullet itself can deposit small residues along the wound track (bullet wipe) that can be seen microscopically and is unrelated to the range of fire. Therefore, the authors conclude there is no utility in the routine histological examination of gunshot wounds for the determination of range of fire.

Macroscopic and pathological assessment of methylene blue and normal saline on postoperative adhesion formation in a rat cecum model.

PubMed

Panahi, Farzad; Sadraie, Seyed Homayoon; Khoshmohabat, Hadi; Shahram, Elias; Kaka, Gholamreza; Hosseinalipour, Mohammad

2012-01-01

Adhesion formation after abdominal surgery is a major cause of postoperative bowel obstruction, infertility, and chronic abdominal pain. In this study, we evaluated the effect of normal saline and methylene blue (MB) on postoperative adhesion formation in a rat cecum model. A total of 30 Wistar female rats in 2 treatment and 1 control groups underwent midline laparotomy and standardized abrasion of the visceral peritoneum. Normal saline and methylene blue were administrated intraperitoneally at the end of the surgical procedure in 2 treatment groups. Fourteen days after surgery, a re-laparotomy was performed for macroscopic and pathological assessment. The adhesion grade and extent of the normal saline group was lower than control and MB groups in macroscopic assessment (P<0.05 for both). A comparison of adhesion stages in pathological assessment showed increment in abdominal adhesion by usage methylene blue 1% and demonstrated significant difference between MB and 2 other groups (P<0.05). Administrated normal saline individually reduce the adhesion grade near cecum. Conversely, usage of methylene blue 1% may unpredictably increase risk of adhesion formation. Copyright © 2012 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

Size effects under homogeneous deformation of single crystals: A discrete dislocation analysis

NASA Astrophysics Data System (ADS)

Guruprasad, P. J.; Benzerga, A. A.

Mechanism-based discrete dislocation plasticity is used to investigate the effect of size on micron scale crystal plasticity under conditions of macroscopically homogeneous deformation. Long-range interactions among dislocations are naturally incorporated through elasticity. Constitutive rules are used which account for key short-range dislocation interactions. These include junction formation and dynamic source and obstacle creation. Two-dimensional calculations are carried out which can handle high dislocation densities and large strains up to 0.1. The focus is laid on the effect of dimensional constraints on plastic flow and hardening processes. Specimen dimensions ranging from hundreds of nanometers to tens of microns are considered. Our findings show a strong size-dependence of flow strength and work-hardening rate at the micron scale. Taylor-like hardening is shown to be insufficient as a rationale for the flow stress scaling with specimen dimensions. The predicted size effect is associated with the emergence, at sufficient resolution, of a signed dislocation density. Heuristic correlations between macroscopic flow stress and macroscopic measures of dislocation density are sought. Most accurate among those is a correlation based on two state variables: the total dislocation density and an effective, scale-dependent measure of signed density.

Cross-scale: multi-scale coupling in space plasmas

NASA Astrophysics Data System (ADS)

Schwartz, Steven J.; Horbury, Timothy; Owen, Christopher; Baumjohann, Wolfgang; Nakamura, Rumi; Canu, Patrick; Roux, Alain; Sahraoui, Fouad; Louarn, Philippe; Sauvaud, Jean-André; Pinçon, Jean-Louis; Vaivads, Andris; Marcucci, Maria Federica; Anastasiadis, Anastasios; Fujimoto, Masaki; Escoubet, Philippe; Taylor, Matt; Eckersley, Steven; Allouis, Elie; Perkinson, Marie-Claire

2009-03-01

Most of the visible universe is in the highly ionised plasma state, and most of that plasma is collision-free. Three physical phenomena are responsible for nearly all of the processes that accelerate particles, transport material and energy, and mediate flows in systems as diverse as radio galaxy jets and supernovae explosions through to solar flares and planetary magnetospheres. These processes in turn result from the coupling amongst phenomena at macroscopic fluid scales, smaller ion scales, and down to electron scales. Cross-Scale, in concert with its sister mission SCOPE (to be provided by the Japan Aerospace Exploration Agency—JAXA), is dedicated to quantifying that nonlinear, time-varying coupling via the simultaneous in-situ observations of space plasmas performed by a fleet of 12 spacecraft in near-Earth orbit. Cross-Scale has been selected for the Assessment Phase of Cosmic Vision by the European Space Agency.

Cross-Scale: multi-scale coupling in space plasmas

NASA Astrophysics Data System (ADS)

Vaivads, A.; Taylor, M. G.

2009-12-01

Most of the visible universe is in the highly ionised plasma state, and most of that plasma is collision-free. Three physical phenomena are responsible for nearly all of the processes that accelerate particles, transport material and energy, and mediate flows in systems as diverse as radio galaxy jets and supernovae explosions through to solar flares and planetary magnetospheres. These processes in turn result from the coupling amongst phenomena at macroscopic fluid scales, smaller ion scales, and down to electron scales. Cross-Scale, in concert with its sister mission SCOPE (to be provided by the Japan Aerospace Exploration Agency—JAXA in collaboration with the Canadian Space Agency), is dedicated to quantifying that nonlinear, time-varying coupling via the simultaneous in-situ observations of space plasmas performed by a fleet of 12 spacecraft in near-Earth orbit. Cross-Scale is currently in the Assessment Phase of ESA's Cosmic Vision.

Reversed rainbow with a nonlocal metamaterial

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morgado, Tiago A., E-mail: tiago.morgado@co.it.pt; Marcos, João S.; Silveirinha, Mário G., E-mail: mario.silveirinha@co.it.pt

2014-12-29

One of the intriguing potentials of metamaterials is the possibility to realize a nonlocal electromagnetic reaction, such that the effective medium response at a given point is fundamentally entangled with the macroscopic field distribution at long distances. Here, it is experimentally and numerically verified that a microwave nonlocal metamaterial formed by crossed metallic wires enables a low-loss broadband anomalous material response such that the refractive index decreases with frequency. Notably, it is shown that an electromagnetic beam refracted by our metamaterial prism creates a reversed microwave rainbow.

Asymptotic quantum elastic generalized Lorenz Mie theory

NASA Astrophysics Data System (ADS)

Gouesbet, G.

2006-10-01

The (electromagnetic) generalized Lorenz-Mie theory describes the interaction between an electromagnetic arbitrary shaped beam and a homogeneous sphere. It is a generalization of the Lorenz-Mie theory which deals with the simpler case of a plane-wave illumination. In a recent paper, we established that, if we restrict ourselves to the study of cross-sections, both for elastic and inelastic scatterings, a macroscopic sphere in Lorenz-Mie theory is formally equivalent to a quantum-like radial potential. To generalize this result, a prerequisite is to possess an asymptotic quantum generalized Lorenz-Mie theory expressing cross-sections in the case of a quantum radial potential interacting with a sub-class of quantum arbitrary wave-packets. Such a theory, restricted however to elastic scattering, is presented in this paper.

Usefulness of combining gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging and contrast-enhanced ultrasound for diagnosing the macroscopic classification of small hepatocellular carcinoma.

PubMed

Kobayashi, Tomoki; Aikata, Hiroshi; Hatooka, Masahiro; Morio, Kei; Morio, Reona; Kan, Hiromi; Fujino, Hatsue; Fukuhara, Takayuki; Masaki, Keiichi; Ohno, Atsushi; Naeshiro, Noriaki; Nakahara, Takashi; Honda, Yohji; Murakami, Eisuke; Kawaoka, Tomokazu; Tsuge, Masataka; Hiramatsu, Akira; Imamura, Michio; Kawakami, Yoshiiku; Hyogo, Hideyuki; Takahashi, Shoichi; Chayama, Kazuaki

2015-11-01

Non-simple nodules in hepatocellular carcinoma (HCC) correlate with poor prognosis. Therefore, we examined the diagnostic ability of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (EOB-MRI) and contrast-enhanced ultrasound (CEUS) for diagnosing the macroscopic classification of small HCCs. A total of 85 surgically resected nodules (≤30 mm) were analyzed. HCCs were pathologically classified as simple nodular (SN) and non-SN. By evaluating hepatobiliary phase (HBP) of EOB-MRI and Kupffer phase of CEUS, the diagnostic abilities of both modalities to correctly distinguish between SN and non-SN were compared. Forty-six nodules were diagnosed as SN and the remaining 39 nodules as non-SN. The area under the ROC curve (AUROCs, 95% confidence interval) for the diagnosis of non-SN were EOB-MRI, 0.786 (0.682-0.890): CEUS, 0.784 (0.679-0.889), in combination, 0.876 (0.792-0.959). The sensitivity, specificity, and accuracy were 64.1%, 95.7%, and 81.2% in EOB-MRI, 56.4%, 97.8%, and 78.8% in CEUS, and 84.6%, 95.7%, and 90.6% in combination, respectively. High diagnostic ability was obtained when diagnosed in both modalities combined. The sensitivity was especially statistically significant compared to CEUS. Combined diagnosis by EOB-MRI and CEUS can provide high-quality imaging assessment for determining non-SN in small HCCs. • Non-SN has a higher frequency of MVI and intrahepatic metastasis than SN. • Macroscopic classification is useful to choose the treatment strategy for small HCCs. • Diagnostic ability for macroscopic findings of EOB-MRI and CEUS were statistically equal. • The diagnosis of macroscopic findings by individual modality has limitations. • Combined diagnosis of EOB-MRI and CEUS provides high diagnostic ability.

Evaluation of Shielding Performance for Newly Developed Composite Materials

NASA Astrophysics Data System (ADS)

Evans, Beren Richard

This work details an investigation into the contributing factors behind the success of newly developed composite neutron shield materials. Monte Carlo simulation methods were utilized to assess the neutron shielding capabilities and secondary radiation production characteristics of aluminum boron carbide, tungsten boron carbide, bismuth borosilicate glass, and Metathene within various neutron energy spectra. Shielding performance and secondary radiation data suggested that tungsten boron carbide was the most effective composite material. An analysis of the macroscopic cross-section contributions from constituent materials and interaction mechanisms was then performed in an attempt to determine the reasons for tungsten boron carbide's success over the other investigated materials. This analysis determined that there was a positive correlation between a non-elastic interaction contribution towards a material's total cross-section and shielding performance within the thermal and epi-thermal energy regimes. This finding was assumed to be a result of the boron-10 absorption reaction. The analysis also determined that within the faster energy regions, materials featuring higher non-elastic interaction contributions were comparable to those exhibiting primarily elastic scattering via low Z elements. This allowed for the conclusion that composite shield success within higher energy neutron spectra does not necessitate the use elastic scattering via low Z elements. These findings suggest that the inclusion of materials featuring high thermal absorption properties is more critical to composite neutron shield performance than the presence of constituent materials more inclined to maximize elastic scattering energy loss.

An integral biochemical analysis of the main constituents of articular cartilage, subchondral and trabecular bone.

PubMed

van der Harst, Mark R; Brama, Pieter A J; van de Lest, Chris H A; Kiers, Geesje H; DeGroot, Jeroen; van Weeren, P René

2004-09-01

In articular joints, the forces generated by locomotion are absorbed by the whole of cartilage, subchondral bone and underlying trabecular bone. The objective of this study is to test the hypothesis that regional differences in joint loading are related to clear and interrelated differences in the composition of the extracellular matrix (ECM) of all three weight-bearing constituents. Cartilage, subchondral- and trabecular bone samples from two differently loaded sites (site 1, dorsal joint margin; site 2, central area) of the proximal articular surface of 30 macroscopically normal equine first phalanxes were collected. Collagen content, cross-linking (pentosidine, hydroxylysylpyridinoline (HP), lysylpyridinoline (LP)) hydroxylation, and denaturation, as well as glycosaminoglycan (GAG) and DNA content were measured in all three tissues. In addition, bone mineral density (BMD), the percentage of ash and the mineral composition (calcium, magnesium and phosphorus) were determined in the bony samples. For pentosidine cross-links there was an expected correlation with age. Denatured collagen content was significantly higher in cartilage at site 1 than at site 2 and was higher in trabecular bone compared to subchondral bone, with no site differences. There were significant site differences in hydroxylysine (Hyl) concentration and HP cross-links in cartilage that were paralleled in one or both of the bony layers. In subchondral bone there was a positive correlation between total (HP+LP) cross-links and Ca content. For Ca and other minerals there were corresponding site differences in both bony layers. It is concluded that there are distinct differences in distribution of the major biochemical components over both sites in all three layers. These differences show similar patterns in cartilage, subchondral bone and trabecular bone, stressing the functional unity of these tissues. Overall, differences could be interpreted as adaptations to a considerably higher cumulative loading over time at site 2, requiring stiffer tissue. Turnover is higher in trabecular bone than in subchondral bone. In cartilage, the dorsal site 1 appears to suffer more tissue damage.

Micro-Macro Coupling in Plasma Self-Organization Processes during Island Coalescence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wan Weigang; Lapenta, Giovanni; Centrum voor Plasma-Astrofysica, Departement Wiskunde, Katholieke Universiteit Leuven, Celestijnenlaan 200B, 3001 Leuven

The collisionless island coalescence process is studied with particle-in-cell simulations, as an internal-driven magnetic self-organization scenario. The macroscopic relaxation time, corresponding to the total time required for the coalescence to complete, is found to depend crucially on the scale of the system. For small-scale systems, where the macroscopic scales and the dissipation scales are more tightly coupled, the relaxation time is independent of the strength of the internal driving force: the small-scale processes of magnetic reconnection adjust to the amount of the initial magnetic flux to be reconnected, indicating that at the microscopic scales reconnection is enslaved by the macroscopicmore » drive. However, for large-scale systems, where the micro-macro scale separation is larger, the relaxation time becomes dependent on the driving force.« less

The association between histological, macroscopic and magnetic resonance imaging assessed synovitis in end-stage knee osteoarthritis: a cross-sectional study.

PubMed

Riis, R G C; Gudbergsen, H; Simonsen, O; Henriksen, M; Al-Mashkur, N; Eld, M; Petersen, K K; Kubassova, O; Bay Jensen, A C; Damm, J; Bliddal, H; Arendt-Nielsen, L; Boesen, M

2017-02-01

To investigate the association between magnetic resonance imaging (MRI), macroscopic and histological assessments of synovitis in end-stage knee osteoarthritis (KOA). Synovitis of end-stage osteoarthritic knees was assessed using non-contrast-enhanced (CE), contrast-enhanced magnetic resonance imaging (CE-MRI) and dynamic contrast-enhanced (DCE)-MRI prior to (TKR) and correlated with microscopic and macroscopic assessments of synovitis obtained intraoperatively. Multiple bivariate correlations were used with a pre-specified threshold of 0.70 for significance. Also, multiple regression analyses with different subsets of MRI-variables as explanatory variables and the histology score as outcome variable were performed with the intention to find MRI-variables that best explain the variance in histological synovitis (i.e., highest R 2 ). A stepped approach was taken starting with basic characteristics and non-CE MRI-variables (model 1), after which CE-MRI-variables were added (model 2) with the final model also including DCE-MRI-variables (model 3). 39 patients (56.4% women, mean age 68 years, Kellgren-Lawrence (KL) grade 4) had complete MRI and histological data. Only the DCE-MRI variable MExNvoxel (surrogate of the volume and degree of synovitis) and the macroscopic score showed correlations above the pre-specified threshold for acceptance with histological inflammation. The maximum R 2 -value obtained in Model 1 was R 2  = 0.39. In Model 2, where the CE-MRI-variables were added, the highest R 2  = 0.52. In Model 3, a four-variable model consisting of the gender, one CE-MRI and two DCE-MRI-variables yielded a R 2  = 0.71. DCE-MRI is correlated with histological synovitis in end-stage KOA and the combination of CE and DCE-MRI may be a useful, non-invasive tool in characterising synovitis in KOA. Copyright © 2016 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Macroscopic quantum states: Measures, fragility, and implementations

NASA Astrophysics Data System (ADS)

Fröwis, Florian; Sekatski, Pavel; Dür, Wolfgang; Gisin, Nicolas; Sangouard, Nicolas

2018-04-01

Large-scale quantum effects have always played an important role in the foundations of quantum theory. With recent experimental progress and the aspiration for quantum enhanced applications, the interest in macroscopic quantum effects has been reinforced. In this review, measures aiming to quantify various aspects of macroscopic quantumness are critically analyzed and discussed. Recent results on the difficulties and prospects to create, maintain, and detect macroscopic quantum states are surveyed. The role of macroscopic quantum states in foundational questions as well as practical applications is outlined. Finally, past and ongoing experimental advances aiming to generate and observe macroscopic quantum states are presented.

Quantitative Analyses of the Modes of Deformation in Engineering Thermoplastics

NASA Astrophysics Data System (ADS)

Landes, B. G.; Bubeck, R. A.; Scott, R. L.; Heaney, M. D.

1998-03-01

Synchrotron-based real-time small-angle X-ray scattering (RTSAXS) studies have been performed on rubber-toughened engineering thermoplastics with amorphous and semi-crystalline matrices. Scattering patterns are measured at successive time intervals of 3 ms were analyzed to determine the plastic strain due to crazing. Simultaneous measurements of the absorption of the primary beam by the sample permits the total plastic strain to be concurrently computed. The plastic strain due to other deformation mechanisms (e.g., particle cavitation and macroscopic shear yield can be determined from the difference between the total and craze-derived plastic strains. The contribution from macroscopic shear deformation can be determined from video-based optical data measured simultaneously with the X-ray data. These types of time-resolved experiments result in the generation of prodigious quantities of data, the analysis of which can considerably delay the determination of key results. A newly developed software package that runs in WINDOWSa 95 permits the rapid analysis of the relative contributions of the deformation modes from these time-resolved experiments. Examples of using these techniques on ABS-type and QUESTRAa syndiotactic polystyrene type engineering resins will be given.

Insufficiency of avoided crossings for witnessing large-scale quantum coherence in flux qubits

NASA Astrophysics Data System (ADS)

Fröwis, Florian; Yadin, Benjamin; Gisin, Nicolas

2018-04-01

Do experiments based on superconducting loops segmented with Josephson junctions (e.g., flux qubits) show macroscopic quantum behavior in the sense of Schrödinger's cat example? Various arguments based on microscopic and phenomenological models were recently adduced in this debate. We approach this problem by adapting (to flux qubits) the framework of large-scale quantum coherence, which was already successfully applied to spin ensembles and photonic systems. We show that contemporary experiments might show quantum coherence more than 100 times larger than experiments in the classical regime. However, we argue that the often-used demonstration of an avoided crossing in the energy spectrum is not sufficient to make a conclusion about the presence of large-scale quantum coherence. Alternative, rigorous witnesses are proposed.

General theory of skin reinforcement.

PubMed

Kruglikov, Ilja L; Scherer, Philipp E

2017-01-01

Macroscopic mechanical properties of human skin in vivo cannot be considered independent of adjacent subcutaneous white adipose tissue (sWAT). The layered system skin/sWAT appears as the hierarchical structural composite in which single layers behave as fiber-reinforced structures. Effective macroscopic mechanical properties of such composites are mainly determined either by the properties of the skin or by those of the sWAT, dependent on the conditions of mechanical loading. Mechanical interactions between the skin and the adjacent sWAT associated with a mismatch in the mechanical moduli of these two layers can lead to production of the skin wrinkles. Reinforcement of the composite skin/sWAT can take place in different ways. It can be provided through reorientation of collagen fibers under applied loading, through production of new bonds between existing collagen fibers and through induction of additional collagen structures. Effectiveness of this type of reinforcement is strongly dependent on the type of mechanical loading. Different physical interventions induce the reinforcement of at least one of these two layers, thus increasing the effective macroscopic stiffness of the total composite. At the same time, the standalone reinforcement of the skin appears to be less effective to achieve a delay or a reduction of the apparent signs of skin aging relative to the reinforcement of the sWAT.

Determination of Diffusion Parameters of Mean Moderation by Means of a Pulsed Neutron Source. I. Dowtherm A at 20 C; DETERMINAZIONE DEI PARAMETRI DI DIFFUSIONE DEI MEZZI MODERANTI CONIL METODO DELLA SORGENTE DI NEUTRONI PULSATA. I.DOWTHERM A (TEMPERATURE 20 C)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Demanins, F.; Rado, V.; Vinci, F.

1963-04-01

The macroscopic absorption cross section, diffusion constant, diffusion cooling constant, transport mean free patu, extrapolated distance, diffusion length, and mean life for thermal neutrons were determined for Dowtherm A at 20 deg C, using a pulsed neutron source. The experimental assembly and data analysis method are described, and the results are compared with other determinations. (auth)

The effect of carbon crystal structure on treat reactor physics calculations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swanson, R.W.; Harrison, L.J.

1988-01-01

The Transient Reactor Test Facility (TREAT) at Argonne National Laboratory-West (ANL-W) is fueled with urania in a graphite and carbon mixture. This fuel was fabricated from a mixture of graphite flour, thermax (a thermatomic carbon produced by ''cracking'' natural gas), coal-tar resin and U/sub 3/O/sub 8/. During the fabrication process, the fuel was baked to dissociate the resin, but the high temperature necessary to graphitize the carbon in the thermax and in the resin was avoided. Therefore, the carbon crystal structure is a complex mixture of graphite particles in a nongraphitized elemental carbon matrix. Results of calculations using macroscopic carbonmore » cross sections obtained by mixing bound-kernel graphite cross sections for the graphitized carbon and free-gas carbon cross sections for the remainder of the carbon and calculations using only bound-kernel graphite cross sections are compared to experimental data. It is shown that the use of the hybridized cross sections which reflect the allotropic mixture of the carbon in the TREAT fuel results in a significant improvement in the accuracy of calculated neutronics parameters for the TREAT reactor. 6 refs., 2 figs., 3 tabs.« less

Anaplasic astrocytoma with exophytic growth in Sylvian fissure in a pediatric patient: a case report

PubMed Central

Bravo-Ángel, Ulises; Hernández-Reséndiz, Rodrigo Efraín; Vicuña-González, Rosa María; Frías-Guillén, Jessica; Bercholc-Urinowsky, Irina Jeanette; Bravo-Reyna, Carlos Cesar; García-González, Ulises

2018-01-01

Abstract Gliomas are the most frequent supratentorial intracranial tumors in the pediatric population. Usually, they are intra-axial lesions with a characteristic image pattern, however, there are few reported cases of gliomas with exophytic growth. There are no previous reports in the literature of gliomas with exophytic growth in the Sylvian fissure. Fourteen year-old female patient who started with seizures. In imaging studies, a neoplasic mass with an exophytic portion in the left Sylvian fissure was found. Macroscopically, total resection was performed, definitive diagnosis was anaplastic astrocytoma. She presented recurrence and is currently receiving adjuvant treatment. Supratentorial gliomas with exophytic growth are extremely rare. We report the first case in the pediatric population, and we consider it is important to know its imaging and macroscopic characteristics for its initial management and to take it into account as a differential diagnosis of exophytic lesions. PMID:29732137

Anaplasic astrocytoma with exophytic growth in Sylvian fissure in a pediatric patient: a case report.

PubMed

Guerra-Mora, José Raúl; Bravo-Ángel, Ulises; Hernández-Reséndiz, Rodrigo Efraín; Vicuña-González, Rosa María; Frías-Guillén, Jessica; Bercholc-Urinowsky, Irina Jeanette; Bravo-Reyna, Carlos Cesar; García-González, Ulises

2018-04-01

Gliomas are the most frequent supratentorial intracranial tumors in the pediatric population. Usually, they are intra-axial lesions with a characteristic image pattern, however, there are few reported cases of gliomas with exophytic growth. There are no previous reports in the literature of gliomas with exophytic growth in the Sylvian fissure. Fourteen year-old female patient who started with seizures. In imaging studies, a neoplasic mass with an exophytic portion in the left Sylvian fissure was found. Macroscopically, total resection was performed, definitive diagnosis was anaplastic astrocytoma. She presented recurrence and is currently receiving adjuvant treatment. Supratentorial gliomas with exophytic growth are extremely rare. We report the first case in the pediatric population, and we consider it is important to know its imaging and macroscopic characteristics for its initial management and to take it into account as a differential diagnosis of exophytic lesions.

Diagnostic accuracy for macroscopic classification of nodular hepatocellular carcinoma: comparison of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging and angiography-assisted computed tomography.

PubMed

Tada, Toshifumi; Kumada, Takashi; Toyoda, Hidenori; Ito, Takanori; Sone, Yasuhiro; Okuda, Seiji; Ogawa, Sadanobu; Igura, Takumi; Imai, Yasuharu

2015-01-01

The macroscopic type of hepatocellular carcinoma (HCC) is a predictor of prognosis. We clarified the diagnostic value of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) in the macroscopic classification of nodular hepatocellular carcinoma (HCC) as compared to angiography-assisted computed tomography (CT). A total of 71 surgically resected nodular HCCs with a maximum diameter of ≤5 cm were investigated. HCCs were evaluated preoperatively using Gd-EOB-DTPA-enhanced MRI and angiography-assisted CT. HCCs were pathologically classified as simple nodular (SN), SN with extranodular growth (SN-EG), or confluent multinodular (CMN). SN-EG and CMN were grouped as non-SN. Five readers independently reviewed the images using a five-point scale. We examined the accuracy of both imaging modalities in differentiating between SN and non-SN HCC. Overall, the area under the receiver operating characteristic curve (A z ) for the diagnosis of non-SN did not differ between Gd-EOB-DTPA-enhanced MRI and angiography-assisted CT [0.879 (95% confidence interval (CI), 0.779-0.937) and 0.845 (95% CI, 0.723-0.919), respectively]. For HCCs >2 cm, the A z for Gd-EOB-DTPA-enhanced MRI was greater than 0.9. The sensitivity, specificity, and accuracy of Gd-EOB-DTPA-enhanced MRI for identifying non-SN were equal to or higher than values with angiography-assisted CT in all three categories (all tumors, ≤2 cm, and >2 cm), but the differences were not statistically significant. Using Gd-EOB-DTPA-enhanced MRI to assess the macroscopic findings in nodular HCC was equal or superior to using angiography-assisted CT.

Averaging problem in general relativity, macroscopic gravity and using Einstein's equations in cosmology.

NASA Astrophysics Data System (ADS)

Zalaletdinov, R. M.

1998-04-01

The averaging problem in general relativity is briefly discussed. A new setting of the problem as that of macroscopic description of gravitation is proposed. A covariant space-time averaging procedure is described. The structure of the geometry of macroscopic space-time, which follows from averaging Cartan's structure equations, is described and the correlation tensors present in the theory are discussed. The macroscopic field equations (averaged Einstein's equations) derived in the framework of the approach are presented and their structure is analysed. The correspondence principle for macroscopic gravity is formulated and a definition of the stress-energy tensor for the macroscopic gravitational field is proposed. It is shown that the physical meaning of using Einstein's equations with a hydrodynamic stress-energy tensor in looking for cosmological models means neglecting all gravitational field correlations. The system of macroscopic gravity equations to be solved when the correlations are taken into consideration is given and described.

Rank distributions: A panoramic macroscopic outlook

NASA Astrophysics Data System (ADS)

Eliazar, Iddo I.; Cohen, Morrel H.

2014-01-01

This paper presents a panoramic macroscopic outlook of rank distributions. We establish a general framework for the analysis of rank distributions, which classifies them into five macroscopic "socioeconomic" states: monarchy, oligarchy-feudalism, criticality, socialism-capitalism, and communism. Oligarchy-feudalism is shown to be characterized by discrete macroscopic rank distributions, and socialism-capitalism is shown to be characterized by continuous macroscopic size distributions. Criticality is a transition state between oligarchy-feudalism and socialism-capitalism, which can manifest allometric scaling with multifractal spectra. Monarchy and communism are extreme forms of oligarchy-feudalism and socialism-capitalism, respectively, in which the intrinsic randomness vanishes. The general framework is applied to three different models of rank distributions—top-down, bottom-up, and global—and unveils each model's macroscopic universality and versatility. The global model yields a macroscopic classification of the generalized Zipf law, an omnipresent form of rank distributions observed across the sciences. An amalgamation of the three models establishes a universal rank-distribution explanation for the macroscopic emergence of a prevalent class of continuous size distributions, ones governed by unimodal densities with both Pareto and inverse-Pareto power-law tails.

Structured pathology reporting improves the macroscopic assessment of rectal tumour resection specimens.

PubMed

King, Simon; Dimech, Margaret; Johnstone, Susan

2016-06-01

We examined whether introduction of a structured macroscopic reporting template for rectal tumour resection specimens improved the completeness and efficiency in collecting key macroscopic data elements. Fifty free text (narrative) macroscopic reports retrieved from 2012 to 2014 were compared with 50 structured macroscopic reports from 2013 to 2015, all of which were generated at John Hunter Hospital, Newcastle, NSW. The six standard macroscopic data elements examined in this study were reported in all 50 anatomical pathology reports using a structured macroscopic reporting dictation template. Free text reports demonstrated significantly impaired data collection when recording intactness of mesorectum (p<0.001), relationship to anterior peritoneal reflection (p=0.028) and distance of tumour to the non-peritonealised circumferential margin (p<0.001). The number of words used was also significantly (p<0.001) reduced using pre-formatted structured reports compared to free text reports. The introduction of a structured reporting dictation template improves data collection and may reduce the subsequent administrative burden when macroscopically evaluating rectal resections. Copyright © 2016 Royal College of Pathologists of Australasia. Published by Elsevier B.V. All rights reserved.

Rank distributions: a panoramic macroscopic outlook.

PubMed

Eliazar, Iddo I; Cohen, Morrel H

2014-01-01

This paper presents a panoramic macroscopic outlook of rank distributions. We establish a general framework for the analysis of rank distributions, which classifies them into five macroscopic "socioeconomic" states: monarchy, oligarchy-feudalism, criticality, socialism-capitalism, and communism. Oligarchy-feudalism is shown to be characterized by discrete macroscopic rank distributions, and socialism-capitalism is shown to be characterized by continuous macroscopic size distributions. Criticality is a transition state between oligarchy-feudalism and socialism-capitalism, which can manifest allometric scaling with multifractal spectra. Monarchy and communism are extreme forms of oligarchy-feudalism and socialism-capitalism, respectively, in which the intrinsic randomness vanishes. The general framework is applied to three different models of rank distributions-top-down, bottom-up, and global-and unveils each model's macroscopic universality and versatility. The global model yields a macroscopic classification of the generalized Zipf law, an omnipresent form of rank distributions observed across the sciences. An amalgamation of the three models establishes a universal rank-distribution explanation for the macroscopic emergence of a prevalent class of continuous size distributions, ones governed by unimodal densities with both Pareto and inverse-Pareto power-law tails.

Quasi-heterogeneous efficient 3-D discrete ordinates CANDU calculations using Attila

DOE Office of Scientific and Technical Information (OSTI.GOV)

Preeti, T.; Rulko, R.

2012-07-01

In this paper, 3-D quasi-heterogeneous large scale parallel Attila calculations of a generic CANDU test problem consisting of 42 complete fuel channels and a perpendicular to fuel reactivity device are presented. The solution method is that of discrete ordinates SN and the computational model is quasi-heterogeneous, i.e. fuel bundle is partially homogenized into five homogeneous rings consistently with the DRAGON code model used by the industry for the incremental cross-section generation. In calculations, the HELIOS-generated 45 macroscopic cross-sections library was used. This approach to CANDU calculations has the following advantages: 1) it allows detailed bundle (and eventually channel) power calculationsmore » for each fuel ring in a bundle, 2) it allows the exact reactivity device representation for its precise reactivity worth calculation, and 3) it eliminates the need for incremental cross-sections. Our results are compared to the reference Monte Carlo MCNP solution. In addition, the Attila SN method performance in CANDU calculations characterized by significant up scattering is discussed. (authors)« less

Two-Dimensional Nonlinear Finite Element Analysis of CMC Microstructures

NASA Technical Reports Server (NTRS)

Mital, Subodh K.; Goldberg, Robert K.; Bonacuse, Peter J.

2011-01-01

Detailed two-dimensional finite element analyses of the cross-sections of a model CVI (chemical vapor infiltrated) SiC/SiC (silicon carbide fiber in a silicon carbide matrix) ceramic matrix composites are performed. High resolution images of the cross-section of this composite material are generated using serial sectioning of the test specimens. These images are then used to develop very detailed finite element models of the cross-sections using the public domain software OOF2 (Object Oriented Analysis of Material Microstructures). Examination of these images shows that these microstructures have significant variability and irregularity. How these variabilities manifest themselves in the variability in effective properties as well as the stress distribution, damage initiation and damage progression is the overall objective of this work. Results indicate that even though the macroscopic stress-strain behavior of various sections analyzed is very similar, each section has a very distinct damage pattern when subjected to in-plane tensile loads and this damage pattern seems to follow the unique architectural and microstructural details of the analyzed sections.

Calculation of fast neutron removal cross sections for different lunar soils

NASA Astrophysics Data System (ADS)

Tellili, B.; Elmahroug, Y.; Souga, C.

2014-01-01

The interaction of galactic cosmic rays (GCRs) and solar energetic particles (SEPs) with the lunar surface produces secondary radiations as neutrons. The study of the production and attenuation of these neutrons in the lunar soil is very important to estimate the annual ambient dose equivalent on the lunar surface and for lunar nuclear spectroscopy. Also, understanding the attenuation of fast neutrons in lunar soils can help in measuring of the lunar neutron density profile and to measure the neutron flux on the lunar surface. In this paper, the attenuation of fast neutrons in different lunar soils is investigated. The macroscopic effective removal cross section (ΣR) of fast neutrons was theoretically calculated from the mass removal cross-section values (ΣR/ρ) for various elements in soils. The obtained values of (ΣR) were discussed according to the density. The results show that the attenuation of fast neutrons is more important in the landing sites of Apollo 12 and Luna 16 than the other landing sites of Apollo and Luna missions.

Microtubule self-organisation by reaction-diffusion processes causes collective transport and organisation of cellular particles

PubMed Central

Glade, Nicolas; Demongeot, Jacques; Tabony, James

2004-01-01

Background The transport of intra-cellular particles by microtubules is a major biological function. Under appropriate in vitro conditions, microtubule preparations behave as a 'complex' system and show 'emergent' phenomena. In particular, they form dissipative structures that self-organise over macroscopic distances by a combination of reaction and diffusion. Results Here, we show that self-organisation also gives rise to a collective transport of colloidal particles along a specific direction. Particles, such as polystyrene beads, chromosomes, nuclei, and vesicles are carried at speeds of several microns per minute. The process also results in the macroscopic self-organisation of these particles. After self-organisation is completed, they show the same pattern of organisation as the microtubules. Numerical simulations of a population of growing and shrinking microtubules, incorporating experimentally realistic reaction dynamics, predict self-organisation. They forecast that during self-organisation, macroscopic parallel arrays of oriented microtubules form which cross the reaction space in successive waves. Such travelling waves are capable of transporting colloidal particles. The fact that in the simulations, the aligned arrays move along the same direction and at the same speed as the particles move, suggest that this process forms the underlying mechanism for the observed transport properties. Conclusions This process constitutes a novel physical chemical mechanism by which chemical energy is converted into collective transport of colloidal particles along a given direction. Self-organisation of this type provides a new mechanism by which intra cellular particles such as chromosomes and vesicles can be displaced and simultaneously organised by microtubules. It is plausible that processes of this type occur in vivo. PMID:15176973

Intratumoral Macroscopic Fat and Hemorrhage Combination Useful in the Differentiation of Benign and Malignant Solid Renal Masses.

PubMed

Sun, Jun; Xing, Zhaoyu; Xing, Wei; Zheng, Linfeng; Chen, Jie; Fan, Min; Chen, Tongbing; Zhang, Zhuoli

2016-03-01

To evaluate the value of combining the detection of intratumoral macroscopic fat and hemorrhage in the differentiation of the benign from malignant solid renal masses.Conventional magnetic resonance imaging (MRI), chemical shift (CS)-MRI, and susceptibility-weighted imaging were performed in 152 patients with 152 solid renal masses, including 48 benign and 104 malignant masses all pathologically confirmed. The presence of macroscopic fat detected by CS-MRI and hemorrhage detected by susceptibility-weighted imaging were evaluated in all masses. The rates of macroscopic fat and hemorrhage observed between benign and malignant masses were compared by a χ test. All masses found to contain macroscopic fat with or without hemorrhage were considered to be benign. The remaining masses (without macroscopic fat) found not to contain hemorrhage were considered to be benign. Only those found to contain hemorrhage alone were considered to be malignant. The evaluation indexes for differentiating and forecasting the benign and malignant masses were calculated.Significant differences in the rate of macroscopic fat (observed in 85.42% of benign masses vs. 0% of malignant masses) and hemorrhage (observed in 4.17% of benign masses vs. 95.19% of malignant masses) were measured in the benign and malignant groups (P < 0.005, for both). The 41 masses containing macroscopic fat with or without hemorrhage and 11 masses containing neither macroscopic fat nor hemorrhage were considered to be benign. The 100 masses containing no macroscopic fat and only hemorrhage were considered to be malignant. By combining the results for the macroscopic fat and hemorrhage, the accuracy, sensitivity, and specificity in the differential diagnosis of the benign and malignant masses were 96.05%, 95.19%, and 97.92%, respectively, and the accuracy and error rate of forecasting the benign and malignant masses were 95.39% and 4.61%, respectively.Combining the detection intratumoral macroscopic fat and hemorrhage can be used to differentiate the benign from malignant solid renal masses.

A quantitative link between microplastic instability and macroscopic deformation behaviors in metallic glasses

NASA Astrophysics Data System (ADS)

Wu, Y.; Chen, G. L.; Hui, X. D.; Liu, C. T.; Lin, Y.; Shang, X. C.; Lu, Z. P.

2009-10-01

Based on mechanical instability of individual shear transformation zones (STZs), a quantitative link between the microplastic instability and macroscopic deformation behavior of metallic glasses was proposed. Our analysis confirms that macroscopic metallic glasses comprise a statistical distribution of STZ embryos with distributed values of activation energy, and the microplastic instability of all the individual STZs dictates the macroscopic deformation behavior of amorphous solids. The statistical model presented in this paper can successfully reproduce the macroscopic stress-strain curves determined experimentally and readily be used to predict strain-rate effects on the macroscopic responses with the availability of the material parameters at a certain strain rate, which offer new insights into understanding the actual deformation mechanism in amorphous solids.

Forensic species identification of elephant (Elephantidae) and giraffe (Giraffidae) tail hair using light microscopy.

PubMed

Yates, Bonnie C; Espinoza, Edgard O; Baker, Barry W

2010-09-01

Here we present methods for distinguishing tail hairs of African elephants (Loxodonta africana), Asian elephants (Elephas maximus), and giraffes (Giraffa camelopardalis) from forensic contexts. Such hairs are commonly used to manufacture jewelry artifacts that are often sold illegally in the international wildlife trade. Tail hairs from these three species are easily confused macroscopically, and morphological methods for distinguishing African and Asian tail hairs have not been published. We used cross section analysis and light microscopy to analyze the tail hair morphology of 18 individual African elephants, 18 Asian elephants, and 40 giraffes. We found that cross-sectional shape, pigment placement, and pigment density are useful morphological features for distinguishing the three species. These observations provide wildlife forensic scientists with an important analytical tool for enforcing legislation and international treaties regulating the trade in elephant parts.

Kinetics of color center formation in silica irradiated with swift heavy ions: Thresholding and formation efficiency

DOE Office of Scientific and Technical Information (OSTI.GOV)

Manzano-Santamaria, J.; Euratom/CIEMAT Fusion Association, Madrid; Olivares, J.

2012-10-08

We have determined the cross-section {sigma} for color center generation under single Br ion impacts on amorphous SiO{sub 2}. The evolution of the cross-sections, {sigma}(E) and {sigma}(S{sub e}), show an initial flat stage that we associate to atomic collision mechanisms. Above a certain threshold value (S{sub e} > 2 keV/nm), roughly coinciding with that reported for the onset of macroscopic disorder (compaction), {sigma} shows a marked increase due to electronic processes. In this regime, a energetic cost of around 7.5 keV is necessary to create a non bridging oxygen hole center-E Prime (NBOHC/E Prime ) pair, whatever the input energy.more » The data appear consistent with a non-radiative decay of self-trapped excitons.« less

Mesoscopic Physics of Electronic and Optical Systems

NASA Astrophysics Data System (ADS)

Hentschel, Martina

2005-10-01

The progress in fabricating and controlling mesoscopic samples opens the possibility to investigate many-body phenomena on the nanoscopic scale, for example in quantum dots or nanoparticles. We recently studied the many-body signatures in the photoabsorption cross-section of those systems. Two counteracting many-body effects (Anderson's orthogonality catastrophe and Mahan's exciton) lead to deviations from the naively expected cross-section and to Fermi-edge singularities in the form of a peaked or rounded edge. We found that mesoscopic-coherent systems can show a many-body response that differs considerably from macroscopic samples. The reason for this lies in the finite number of particles and the lack of rotational symmetry in generic mesoscopic systems. The properties of mesoscopic systems crucially depend on whether the corresponding classical systems possess chaotic or integrable dynamics. Signatures of the underlying classical dynamics in quantum-mechanical behavior are searched for in the field of quantum chaos. We study it in the context of optical microresonators-billiards where reflection at hard walls is replaced by confinement due to total internal reflection. The relation between the simple ray model and the wave description (that has to be used when the wavelength becomes comparable to the system size) is called ``ray-wave correspondence.'' It can be established in both real and phase space. For the latter we generalized the concept of Husimi functions to dielectric boundaries. Although the ray model provides a qualitative understanding of the system properties even into the wave limit, semiclassical corrections of the ray picture are necessary in order to establish quantitative correspondence.

Hauser-Feshbach fission fragment de-excitation with calculated macroscopic-microscopic mass yields

NASA Astrophysics Data System (ADS)

Jaffke, Patrick; Möller, Peter; Talou, Patrick; Sierk, Arnold J.

2018-03-01

The Hauser-Feshbach statistical model is applied to the de-excitation of primary fission fragments using input mass yields calculated with macroscopic-microscopic models of the potential energy surface. We test the sensitivity of the prompt fission observables to the input mass yields for two important reactions, 235U(nth,f ) and 239Pu(nth,f ) , for which good experimental data exist. General traits of the mass yields, such as the location of the peaks and their widths, can impact both the prompt neutron and γ -ray multiplicities, as well as their spectra. Specifically, we use several mass yields to determine a linear correlation between the calculated prompt neutron multiplicity ν ¯ and the average heavy-fragment mass 〈Ah〉 of the input mass yields ∂ ν ¯/∂ 〈Ah〉 =±0.1 (n /f ) /u . The mass peak width influences the correlation between the total kinetic energy of the fission fragments and the total number of prompt neutrons emitted, ν¯T(TKE ) . Typical biases on prompt particle observables from using calculated mass yields instead of experimental ones are δ ν ¯=4 % for the average prompt neutron multiplicity, δ M ¯γ=1 % for the average prompt γ -ray multiplicity, δ ɛ¯nLAB=1 % for the average outgoing neutron energy, δ ɛ¯γ=1 % for the average γ -ray energy, and δ 〈TKE 〉=0.4 % for the average total kinetic energy of the fission fragments.

Explicit dosimetry for 2-(1-hexyloxyethyl)-2-devinyl pyropheophorbide-a-mediated photodynamic therapy: macroscopic singlet oxygen modeling.

PubMed

Penjweini, Rozhin; Liu, Baochang; Kim, Michele M; Zhu, Timothy C

2015-01-01

Type II photodynamic therapy (PDT) is based on the photochemical reactions mediated through an interaction between a photosensitizer, ground-state oxygen ([(3)O2]), and light excitation at an appropriate wavelength, which results in production of reactive singlet oxygen ([(1)O2]rx). We use an empirical macroscopic model based on four photochemical parameters for the calculation of [(1)O2]rx threshold concentration ([(1)O2]rx,sh) causing tissue necrosis in tumors after PDT. For this reason, 2-(1-hexyloxyethyl)-2-devinyl pyropheophorbide-a (HPPH)-mediated PDT was performed interstitially on mice with radiation-induced fibrosarcoma (RIF) tumors. A linear light source at 665 nm with total energy released per unit length of 12 to 100  J/cm and source power per unit length (LS) of 12 to 150  mW/cm was used to induce different radii of necrosis. Then the amount of [(1)O2]rx calculated by the macroscopic model incorporating explicit PDT dosimetry of light fluence distribution, tissue optical properties, and HPPH concentration was correlated to the necrotic radius to obtain the model parameters and [(1)O2]rx,sh. We provide evidence that [(1)O2]rx is a better dosimetric quantity for predicting the treatment outcome than PDT dose, which is proportional to the time integral of the products of the photosensitizer concentration and light fluence rate.

Explicit dosimetry for 2-(1-hexyloxyethyl)-2-devinyl pyropheophorbide-a-mediated photodynamic therapy: macroscopic singlet oxygen modeling

PubMed Central

Penjweini, Rozhin; Liu, Baochang; Kim, Michele M.; Zhu, Timothy C.

2015-01-01

Abstract. Type II photodynamic therapy (PDT) is based on the photochemical reactions mediated through an interaction between a photosensitizer, ground-state oxygen ([O32]), and light excitation at an appropriate wavelength, which results in production of reactive singlet oxygen ([O12]rx). We use an empirical macroscopic model based on four photochemical parameters for the calculation of [O12]rx threshold concentration ([O12]rx,sh) causing tissue necrosis in tumors after PDT. For this reason, 2-(1-hexyloxyethyl)-2-devinyl pyropheophorbide-a (HPPH)-mediated PDT was performed interstitially on mice with radiation-induced fibrosarcoma (RIF) tumors. A linear light source at 665 nm with total energy released per unit length of 12 to 100  J/cm and source power per unit length (LS) of 12 to 150  mW/cm was used to induce different radii of necrosis. Then the amount of [O12]rx calculated by the macroscopic model incorporating explicit PDT dosimetry of light fluence distribution, tissue optical properties, and HPPH concentration was correlated to the necrotic radius to obtain the model parameters and [O12]rx,sh. We provide evidence that [O12]rx is a better dosimetric quantity for predicting the treatment outcome than PDT dose, which is proportional to the time integral of the products of the photosensitizer concentration and light fluence rate. PMID:26720883

Explicit dosimetry for 2-(1-hexyloxyethyl)-2-devinyl pyropheophorbide-a-mediated photodynamic therapy: macroscopic singlet oxygen modeling

NASA Astrophysics Data System (ADS)

Penjweini, Rozhin; Liu, Baochang; Kim, Michele M.; Zhu, Timothy C.

2015-12-01

Type II photodynamic therapy (PDT) is based on the photochemical reactions mediated through an interaction between a photosensitizer, ground-state oxygen ([O]), and light excitation at an appropriate wavelength, which results in production of reactive singlet oxygen ([]rx). We use an empirical macroscopic model based on four photochemical parameters for the calculation of []rx threshold concentration ([]rx,sh) causing tissue necrosis in tumors after PDT. For this reason, 2-(1-hexyloxyethyl)-2-devinyl pyropheophorbide-a (HPPH)-mediated PDT was performed interstitially on mice with radiation-induced fibrosarcoma (RIF) tumors. A linear light source at 665 nm with total energy released per unit length of 12 to 100 J/cm and source power per unit length (LS) of 12 to 150 mW/cm was used to induce different radii of necrosis. Then the amount of []rx calculated by the macroscopic model incorporating explicit PDT dosimetry of light fluence distribution, tissue optical properties, and HPPH concentration was correlated to the necrotic radius to obtain the model parameters and []rx,sh. We provide evidence that []rx is a better dosimetric quantity for predicting the treatment outcome than PDT dose, which is proportional to the time integral of the products of the photosensitizer concentration and light fluence rate.

A rat hysteropexy model for evaluating adhesion formation and comparison of two different structured meshes.

PubMed

Gokmen-Karasu, Ayse Filiz; Aydin, Serdar; Sonmez, Fatma Cavide; Adanir, Ilknur; Ilhan, Gulsah; Ates, Seda

2017-11-01

Peritonization of mesh during sacrohysteropexy is generally advocated to prevent adhesions to the viscera; however, randomized clinical trials are lacking, and peritonization may not be completely possible in a laparoscopic hysteropexy procedure. Our main objective was to describe a basic experimental rat sacrohysteropexy model. We hypothesized that even when peritoneal closure was omitted, using composite mesh would result in less adhesions to the viscera. Twenty in-bred female virgin Wistar Hannover rats were used in this study. Standardized hysteropexy procedure and adhesion model is described step by step with two different mesh materials: polypropylene and a composite polyester. Mesh was anchored between the posterior cervix and anterior longitudinal ligament of the lumbar vertebrae. Macroscopic adhesion scores and histopathological tissue reaction was investigated. Macroscopically, the surface area involved in adhesions was similar between groups. However, adhesions in the polypropylene group were more dense, required sharp dissection for lysis, and yielded higher total macroscopic adhesion scores (p < 0.001). Histologically, a more pronounced host inflammatory response was encountered in the polyester group (p < 0.001). We describe a rat hysteropexy model and a previously established uterine adhesion model. Adhesion scores in the composite mesh group were lower, and bowel involvement was not seen. Our findings are promising, and further research investigating antiadhesive composite mesh use for hysterosacropexy would be appropriate, especially when peritoneal closure is omitted.

Goethite surface reactivity: a macroscopic investigation unifying proton, chromate, carbonate, and lead(II) adsorption.

PubMed

Villalobos, Mario; Pérez-Gallegos, Ayax

2008-10-15

The goethite surface structure has been extensively studied, but no convincing quantitative description of its highly variable surface reactivity as inversely related to its specific surface area (SSA) has been found. The present study adds experimental evidence and provides a unified macroscopic explanation to this anomalous behavior from differences in average adsorption capacities, and not in average adsorption affinities. We investigated the chromate anion and lead(II) cation adsorption behavior onto three different goethites with SSA varying from 50 to 94 m(2)/g, and analyzed an extensive set of published anion adsorption and proton charging data for variable SSA goethites. Maximum chromate adsorption was found to occupy on average from 3.1 to 9.7 sites/nm(2), inversely related to SSA. Congruency of oxyanion and Pb(II) adsorption behavior based on fractional site occupancy using these values, and a site density analysis suggest that: (i) ion binding occurs to singly and doubly coordinated sites, (ii) proton binding occurs to singly and triply coordinated sites (ranging from 6.2 to 8 total sites/nm(2), in most cases), and (iii) a predominance of (210) and/or (010) faces explains the high reactivity of low SSA goethites. The results imply that the macroscopic goethite adsorption behavior may be predicted without a need to investigate extensive structural details of each specific goethite of interest.

Triple diagnostics for early detection of ambivalent necrotizing fasciitis.

PubMed

Hietbrink, Falco; Bode, Lonneke G; Riddez, Louis; Leenen, Luke P H; van Dijk, Marijke R

2016-01-01

Necrotizing fasciitis is an uncommon, rapidly progressive and potential lethal condition. Over the last decade time to surgery decreased and outcome improved, most likely due to increased awareness and more timely referral. Early recognition is key to improve mortality and morbidity. However, early referral frequently makes it a challenge to recognize this heterogeneous disease in its initial stages. Signs and symptoms might be misleading or absent, while the most prominent skin marks might be in discrepancy with the position of the fascial necrosis. Gram staining and especially fresh frozen section histology might be a useful adjunct. Retrospective analysis of 3 year period. Non-transferred patients who presented with suspected necrotizing fasciitis are included. ASA classification was determined. Mortality was documented. In total, 21 patients are included. Most patients suffered from severe comorbidities. In 11 patients, diagnoses was confirmed based on intra-operative macroscopic findings. Histology and/or microbiotic findings resulted in 6/10 remaining patients in a change in treatment strategy. In total, 17 patients proved to suffer necrotizing fasciitis. In the cohort series 2 patients died due to necrotizing fasciitis. In the early phases of necrotizing fasciitis, clinical presentation can be ambivalent. In the present cohort, triple diagnostics consisting of an incisional biopsy with macroscopic, histologic and microbiotic findings was helpful in timely identification of necrotizing fasciitis.

Occurrence of Capillaria sp. in the liver of sheep (Ovis aries ) in a slaughterhouse in the state of Acre, Brazil.

PubMed

Teixeira, Paulo Eduardo Ferlini; Corrêa, Christiane Leal; Oliveira, Fernanda Bittencourt de; Alencar, Alba Cristina Miranda de Barros; Neves, Leandro Batista das; Garcia, Daniel Daipert; Almeida, Fernanda Barbosa de; Pereira, Luis Cláudio Muniz; Machado-Silva, José Roberto; Rodrigues-Silva, Rosângela

2018-01-01

Although sheep farming has grown in the state of Acre over the past four decades, little is known about occurrences of helminthiases in the herds of this region. The objective of the study was to assess the occurrences of non-intestinal helminthiasis among sheep slaughtered in Rio Branco. A total of 110 sheep livers were inspected from two slaughter batches (july 2014 and march 2015) in a slaughterhouse in Rio Branco. Livers with macroscopic lesions were photographed and were then subjected to histopathological analysis under an optical microscope. The macroscopic lesions showed small nodes with inflammatory characteristics and areas of fibrosis, which appeared to be calcified, thus suggesting a granulomatous reaction. Of the 110 evaluated livers, we noticed 110 nodules in total; these nodules have an average size of 0.5 cm. The histopathological analysis showed alterations to the architecture of the hepatic lobe, with multiple foci of necrosis and polymorphonuclear cells. Two samples revealed the presence of helminths from Nematode class and Capillaria sp. eggs identified by the typical morphology and morphometry. This seems to be the first report of Capillaria sp. in sheep livers in Brazil, and it serves as an important alert regarding animal health surveillance and control and regarding the Capillaria sp. zoonotic role in humans.

Factors affecting the serological testing of cadaveric donor cornea.

PubMed

Raj, Anuradha; Mittal, Garima; Bahadur, Harsh

2018-01-01

The purpose of this study was to evaluate the serological profile of the eye donors and to study the influence of various factors on serological test results. A cross-sectional, observational study was conducted, and data of 509 donors were reviewed from the records of eye bank from December 2012 to June 2017. Various details of donors analyzed included the age, sex of the donor, cause of death, source of tissue, time since blood collection after death, macroscopic appearance of blood sample, and details of discarded tissues. Serological examination of blood was performed for human immunodeficiency virus (HIV), hepatitis B virus, hepatitis C virus (HCV), venereal disease research laboratory (VDRL), and serology reports reactive or nonreactive were analyzed. Among the 509 donors, 295 (58%) were male, and 420 (82.50%) belonged to age group ≥60 years. Most donors (354, 69.5%) died due to cardiac arrest. Macroscopically, sera were normal in the majority of 488 (95.9%) cases. Among 509 donors, 475 (93.3%) were nonreactive, 12 (2.4%) donors were found to be reactive to hepatitis B surface antigen (HBsAg), and 1 (0.2%) was reactive to HCV, but no donor serology was reactive to HIV or VDRL. Twenty-one (4.12%) donors' sera were not fit for serological testing. Among all donors, 475 (93.32%) donors were accepted and 34 (6.67%) were rejected or discarded on the basis of serological testing. Cause of death and macroscopic aspect of sera influenced the serological results in a highly significant manner (P = 0.00). Acceptance or rejection of the donor was significantly influenced by the serological results of the donor (P = 0.00). The seroprevalence among eye donor for HBsAg and HCV was 12 (2.4%) and 1 (0.2%), respectively. Factors such as cause of death and macroscopic aspect of sera influence the serological results. Time since blood collection or sampling will not show any impact on viral serological results if postmortem sampling will be done in < 10 hours(h) after death which can improve the safety and utility of the donor cornea.

Increasing the switching speed of liquid crystal devices with magnetic nanorods

NASA Astrophysics Data System (ADS)

Garbovskiy, Yu.; Baptist, J. R.; Thompson, J.; Hunter, T.; Lim, J. H.; Gi Min, Seong; Wiley, J. B.; Malkinski, L. M.; Glushchenko, A.; Celinski, Z.

2012-10-01

Liquid crystal (LC)/magnetic nanorods colloids were fabricated and tested using a magneto-optical setup. These thermotropic ferronematics do not show any signs of macroscopic aggregation, exhibit enhanced magnetic sensitivity, and faster time response in the simultaneous presence of crossed electric and magnetic fields. Magnetic nanorods increase an effective magnetic anisotropy of the colloid and decrease magnetic Freedericksz threshold. Applying a magnetic field along the direction perpendicular to the applied electric field leads to a decrease of the time OFF by a factor of 6 for pure liquid crystals, and by a factor of 9—for ferronematics.

Particle Interactions Mediated by Dynamical Networks: Assessment of Macroscopic Descriptions

NASA Astrophysics Data System (ADS)

Barré, J.; Carrillo, J. A.; Degond, P.; Peurichard, D.; Zatorska, E.

2018-02-01

We provide a numerical study of the macroscopic model of Barré et al. (Multiscale Model Simul, 2017, to appear) derived from an agent-based model for a system of particles interacting through a dynamical network of links. Assuming that the network remodeling process is very fast, the macroscopic model takes the form of a single aggregation-diffusion equation for the density of particles. The theoretical study of the macroscopic model gives precise criteria for the phase transitions of the steady states, and in the one-dimensional case, we show numerically that the stationary solutions of the microscopic model undergo the same phase transitions and bifurcation types as the macroscopic model. In the two-dimensional case, we show that the numerical simulations of the macroscopic model are in excellent agreement with the predicted theoretical values. This study provides a partial validation of the formal derivation of the macroscopic model from a microscopic formulation and shows that the former is a consistent approximation of an underlying particle dynamics, making it a powerful tool for the modeling of dynamical networks at a large scale.

Particle Interactions Mediated by Dynamical Networks: Assessment of Macroscopic Descriptions.

PubMed

Barré, J; Carrillo, J A; Degond, P; Peurichard, D; Zatorska, E

2018-01-01

We provide a numerical study of the macroscopic model of Barré et al. (Multiscale Model Simul, 2017, to appear) derived from an agent-based model for a system of particles interacting through a dynamical network of links. Assuming that the network remodeling process is very fast, the macroscopic model takes the form of a single aggregation-diffusion equation for the density of particles. The theoretical study of the macroscopic model gives precise criteria for the phase transitions of the steady states, and in the one-dimensional case, we show numerically that the stationary solutions of the microscopic model undergo the same phase transitions and bifurcation types as the macroscopic model. In the two-dimensional case, we show that the numerical simulations of the macroscopic model are in excellent agreement with the predicted theoretical values. This study provides a partial validation of the formal derivation of the macroscopic model from a microscopic formulation and shows that the former is a consistent approximation of an underlying particle dynamics, making it a powerful tool for the modeling of dynamical networks at a large scale.

Multiscale Morphology of Nanoporous Copper Made from Intermetallic Phases

DOE PAGES

Egle, Tobias; Barroo, Cédric; Janvelyan, Nare; ...

2017-07-11

Many application-relevant properties of nanoporous metals critically depend on their multiscale architecture. For example, the intrinsically high step-edge density of curved surfaces at the nanoscale provides highly reactive sites for catalysis, whereas the macroscale pore and grain morphology determines the macroscopic properties, such as mass transport, electrical conductivity, or mechanical properties. Here, in this work, we systematically study the effects of alloy composition and dealloying conditions on the multiscale morphology of nanoporous copper (np-Cu) made from various commercial Zn–Cu precursor alloys. Using a combination of X-ray diffraction, electron backscatter diffraction, and focused ion beam cross-sectional analysis, our results reveal thatmore » the macroscopic grain structure of the starting alloy surprisingly survives the dealloying process, despite a change in crystal structure from body-centered cubic (Zn–Cu starting alloy) to face-centered cubic (Cu). The nanoscale structure can be controlled by the acid used for dealloying with HCl leading to a larger and more faceted ligament morphology compared to that of H 3PO 4. Finally, anhydrous ethanol dehydrogenation was used as a probe reaction to test the effect of the nanoscale ligament morphology on the apparent activation energy of the reaction.« less

Multiscale Morphology of Nanoporous Copper Made from Intermetallic Phases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Egle, Tobias; Barroo, Cédric; Janvelyan, Nare

Many application-relevant properties of nanoporous metals critically depend on their multiscale architecture. For example, the intrinsically high step-edge density of curved surfaces at the nanoscale provides highly reactive sites for catalysis, whereas the macroscale pore and grain morphology determines the macroscopic properties, such as mass transport, electrical conductivity, or mechanical properties. Here, in this work, we systematically study the effects of alloy composition and dealloying conditions on the multiscale morphology of nanoporous copper (np-Cu) made from various commercial Zn–Cu precursor alloys. Using a combination of X-ray diffraction, electron backscatter diffraction, and focused ion beam cross-sectional analysis, our results reveal thatmore » the macroscopic grain structure of the starting alloy surprisingly survives the dealloying process, despite a change in crystal structure from body-centered cubic (Zn–Cu starting alloy) to face-centered cubic (Cu). The nanoscale structure can be controlled by the acid used for dealloying with HCl leading to a larger and more faceted ligament morphology compared to that of H 3PO 4. Finally, anhydrous ethanol dehydrogenation was used as a probe reaction to test the effect of the nanoscale ligament morphology on the apparent activation energy of the reaction.« less

Histopathologic Findings of Cholecystectomy Specimens in Patients Who Underwent Donor Hepatectomy for Living Donor Liver Transplantation.

PubMed

Akbulut, S; Karagul, S; Ertugrul, I; Aydin, C; Yilmaz, M; Yilmaz, S

2015-06-01

The aim of this study was to discuss the macroscopic and microscopic properties of gallbladder specimens obtained from living liver donors. The study retrospectively analyzed the clinical and histopathological data of 1088 donors who underwent living donor hepatectomy between March 2005 and September 2014 at Inonu University Faculty of Medicine, Liver Transplantation Center. Age, sex, macroscopic, and microscopic properties of the gallbladder (bladder length, diameter, content, and histopathological properties) were recorded by 2 researchers. A total of 1009 donors aged 17 to 66 years (31.1 ± 9.5) met the inclusion criteria, whereas 79 donors were excluded due to missing data. In total, 587 donors were male (30.5 ± 9.1 years [16-63 years]) and 422 were female (31.8 ± 9.8 years [18-66 years]). Preoperative tests revealed Gilbert syndrome in 3 subjects, whereas other donors' biochemical tests were within normal ranges. The macroscopic examination of gallbladders revealed mean gallbladder wall thickness, length, and width of 1.82 ± 0.8 mm (1-10 mm), 72 ± 11.4 mm (40-120 mm), and 52.5 ± 14 mm (15-90 mm), respectively. The microscopic gallbladder examination showed that 740 donors had a normal gallbladder, 193 had chronic cholecystitis (1 donor had antral metaplasia and 1 had intestinal metaplasia), 40 had cholesterolosis (1 donor had both tubular adenoma and intestinal metaplasia), 15 had minimal chronic cholecystitis (1 donor had pyloric metaplasia), 14 had cholelithiasis, 2 had adenomyosis, 2 had muscular hypertrophy, 1 had papillary hyperplasia, 1 had microdiverticulitis, and 1 had mucosal lymphatic ectasia. The results of this study reflect the actual gallbladder pathologies that can be detected in healthy people. Clearer conclusions can be reached about the epidemiological data on gallbladder as the number of living liver donors increases in the future. Copyright © 2015 Elsevier Inc. All rights reserved.

Anisotropic mechanical behaviors and their structural dependences of crossed-lamellar structure in a bivalve shell.

PubMed

Jiao, D; Liu, Z Q; Qu, R T; Zhang, Z F

2016-02-01

Crossed-lamellar structure is one of the most common organizations found in mollusk shells and may serve as a natural mimetic model for designing bio-inspired synthetic materials. Nonetheless, the mechanical behaviors and corresponding mechanisms have rarely been investigated for individual macro-layer of such structure. The integrated effects of orientation and hydration also remain unclear. In this study, the mechanical behaviors and their structural dependences of pure crossed-lamellar structure in Saxidomus purpuratus shell were systematically examined by three-point bending and compression tests. Mechanical properties and fracture mechanisms were revealed to depend strongly on the orientation, hydration state and loading condition. Three basic cracking modes of inter-platelet, trans-platelet, and along the interfaces between first-order lamellae were identified, and the interfacial separation was enhanced by hydration. Macroscopic compressive fracture was accomplished through axial splitting during which multiple toughening mechanisms were activated. The competition among different cracking modes was quantitatively evaluated by analyzing their driving stresses and resistances from fundamental mechanics. This study helps to clarify the mechanical behaviors of naturally occurring crossed-lamellar structure, and accordingly, aids in designing new bio-inspired synthetic materials by mimicking it. Copyright © 2015 Elsevier B.V. All rights reserved.

Macroscopic erosion of divertor and first wall armour in future tokamaks

NASA Astrophysics Data System (ADS)

Würz, H.; Bazylev, B.; Landman, I.; Pestchanyi, S.; Safronov, V.

2002-12-01

Sputtering, evaporation and macroscopic erosion determine the lifetime of the 'in vessel' armour materials CFC, tungsten and beryllium presently under discussion for future tokamaks. For CFC armour macroscopic erosion means brittle destruction and dust formation whereas for metallic armour melt layer erosion by melt motion and droplet splashing. Available results on macroscopic erosion from hot plasma and e-beam simulation experiments and from tokamaks are critically evaluated and a comprehensive discussion of experimental and numerical macroscopic erosion and its extrapolation to future tokamaks is given. Shielding of divertor armour materials by their own vapor exists during plasma disruptions. The evolving plasma shield protects the armour from high heat loads, absorbs the incoming energy and reradiates it volumetrically thus reducing drastically the deposited energy. As a result, vertical target erosion by vaporization turns out to be of the order of a few microns per disruption event and macroscopic erosion becomes the dominant erosion source.

Integral cross sections for electron impact excitation of electronic states of N2

NASA Astrophysics Data System (ADS)

Campbell, L.; Brunger, M. J.; Nolan, A. M.; Kelly, L. J.; Wedding, A. B.; Harrison, J.; Teubner, P. J. O.; Cartwright, D. C.; McLaughlin, B.

2001-04-01

We report integral cross sections (ICSs) for electron impact excitation of the A 3Σ+u, B 3Πg, W 3Δu, B' 3Σ-u, a' 1Σ-u, a 1Πg, ω1Δu, C 3Πu, E 3Σ+g and a'' 1Σ+g electronic states of N2. The present data, for each state, were derived at five incident electron energies in the range 15-50 eV, from the earlier crossed-beam differential cross section (DCS) measurements of our group. This was facilitated by using a molecular phase shift analysis technique to extrapolate the measured DCSs to 0° and 180°, before performing the integration. A comprehensive comparison of the present ICSs with the results of earlier experimental studies, both crossed beam and electron swarm, and theoretical calculations is provided. This comparison clearly indicates that some of the previous estimates for these excited electronic-state cross sections need to be reassessed. In addition, we have used the present ICSs in a Monte Carlo simulation for modelling the behaviour of an electron swarm in the bulk of a low current N2 discharge. The macroscopic transport parameters determined from this simulation are compared against those measured from independent swarm-based experiments and the self-consistency of our ICSs evaluated.

Calculation of total and ionization cross sections for electron scattering by primary benzene compounds

NASA Astrophysics Data System (ADS)

Singh, Suvam; Naghma, Rahla; Kaur, Jaspreet; Antony, Bobby

2016-07-01

The total and ionization cross sections for electron scattering by benzene, halobenzenes, toluene, aniline, and phenol are reported over a wide energy domain. The multi-scattering centre spherical complex optical potential method has been employed to find the total elastic and inelastic cross sections. The total ionization cross section is estimated from total inelastic cross section using the complex scattering potential-ionization contribution method. In the present article, the first theoretical calculations for electron impact total and ionization cross section have been performed for most of the targets having numerous practical applications. A reasonable agreement is obtained compared to existing experimental observations for all the targets reported here, especially for the total cross section.

Protein recognition by a pattern-generating fluorescent molecular probe.

PubMed

Pode, Zohar; Peri-Naor, Ronny; Georgeson, Joseph M; Ilani, Tal; Kiss, Vladimir; Unger, Tamar; Markus, Barak; Barr, Haim M; Motiei, Leila; Margulies, David

2017-12-01

Fluorescent molecular probes have become valuable tools in protein research; however, the current methods for using these probes are less suitable for analysing specific populations of proteins in their native environment. In this study, we address this gap by developing a unimolecular fluorescent probe that combines the properties of small-molecule-based probes and cross-reactive sensor arrays (the so-called chemical 'noses/tongues'). On the one hand, the probe can detect different proteins by generating unique identification (ID) patterns, akin to cross-reactive arrays. On the other hand, its unimolecular scaffold and selective binding enable this ID-generating probe to identify combinations of specific protein families within complex mixtures and to discriminate among isoforms in living cells, where macroscopic arrays cannot access. The ability to recycle the molecular device and use it to track several binding interactions simultaneously further demonstrates how this approach could expand the fluorescent toolbox currently used to detect and image proteins.

Rational design of capillary-driven flows for paper-based microfluidics.

PubMed

Elizalde, Emanuel; Urteaga, Raúl; Berli, Claudio L A

2015-05-21

The design of paper-based assays that integrate passive pumping requires a precise programming of the fluid transport, which has to be encoded in the geometrical shape of the substrate. This requirement becomes critical in multiple-step processes, where fluid handling must be accurate and reproducible for each operation. The present work theoretically investigates the capillary imbibition in paper-like substrates to better understand fluid transport in terms of the macroscopic geometry of the flow domain. A fluid dynamic model was derived for homogeneous porous substrates with arbitrary cross-sectional shapes, which allows one to determine the cross-sectional profile required for a prescribed fluid velocity or mass transport rate. An extension of the model to slit microchannels is also demonstrated. Calculations were validated by experiments with prototypes fabricated in our lab. The proposed method constitutes a valuable tool for the rational design of paper-based assays.

Protein recognition by a pattern-generating fluorescent molecular probe

NASA Astrophysics Data System (ADS)

Pode, Zohar; Peri-Naor, Ronny; Georgeson, Joseph M.; Ilani, Tal; Kiss, Vladimir; Unger, Tamar; Markus, Barak; Barr, Haim M.; Motiei, Leila; Margulies, David

2017-12-01

Fluorescent molecular probes have become valuable tools in protein research; however, the current methods for using these probes are less suitable for analysing specific populations of proteins in their native environment. In this study, we address this gap by developing a unimolecular fluorescent probe that combines the properties of small-molecule-based probes and cross-reactive sensor arrays (the so-called chemical 'noses/tongues'). On the one hand, the probe can detect different proteins by generating unique identification (ID) patterns, akin to cross-reactive arrays. On the other hand, its unimolecular scaffold and selective binding enable this ID-generating probe to identify combinations of specific protein families within complex mixtures and to discriminate among isoforms in living cells, where macroscopic arrays cannot access. The ability to recycle the molecular device and use it to track several binding interactions simultaneously further demonstrates how this approach could expand the fluorescent toolbox currently used to detect and image proteins.

Experimental pleurodesis induced by antibiotics (macrolides or quinolones).

PubMed

Teixeira, Lisete R; Vargas, Francisco S; Acencio, Milena M P; Bumlai, Renan U M; Antonangelo, Leila; Marchi, Evaldo

2006-12-01

Chemical pleurodesis is a therapeutic tool for the treatment of recurrent pleural effusions, mainly those of neoplastic etiology. In the past, tetracycline was the sclerosant agent of choice in clinical practice, but presently, there is no consensus about an ideal agent. The aim of this study was to evaluate the effectiveness of macrolides (azithromycin and clarithromycin) or quinolones (levofloxacin and gatifloxacin) in inducing experimental pleurodesis in rabbits. Forty New Zealand rabbits randomized into groups of 10 received (at a total volume of 2 mL for each animal) 1 of the 4 drugs by intrapleural injection. After 28 days, the animals were euthanized and the pleural cavity was evaluated macroscopically and microscopically. The intensity of the macroscopic adhesions was mild in all groups. On microscopic analysis, minimal pleural fibrosis and inflammation were observed in all animals. The macrolides (azithromycin or clarithromycin) and the quinolones (levofloxacin or gatifloxacin) when injected into the normal pleural space of rabbits are not effective in promoting pleurodesis. Additional research is required to identify sclerosing agents capable of inducing pleurodesis.

Aggregata (Protozoa: Apicomplexa) infection in the common octopus Octopus vulgaris from the West Mediterranean Sea: The infection rates and possible effect of faunistic, environmental and ecological factors

NASA Astrophysics Data System (ADS)

Mayo-Hernández, E.; Barcala, E.; Berriatua, E.; García-Ayala, A.; Muñoz, P.

2013-10-01

Prevalence and distribution of the coccidian parasite Aggregata octopiana (Protozoa: Apicomplexa) in common octopus (Octopus vulgaris) in the Mediterranean Spanish coasts were studied. A total of 114 octopuses were sampled from 30 geographic sectors by trawl fleet, and whitish macroscopic oocysts typical of A. octopiana infection were recorded in 96% of octopuses in the digestive tract and mainly in intestine and spiral caecum. The univariate analysis showed that lesion extension varied according to specific octopus, environmental and faunistic variables. A subsequent multivariable analysis indicated that the risk of macroscopic lesions in the caecum was greater in males compared to females, in octopuses living in deeper compared to shallower waters and in hauls where the crustacean Pagurus excavatus was present. The study provides further evidence of the abundance of A. octopiana in octopus ecosystems urging for further studies to evaluate its health impact. The combined abundance of infected octopuses and P. excavatus merits attention.

Comparison of macroscopic and microscopic (stereomicroscopy and scanning electron microscopy) features of bone lesions due to hatchet hacking trauma.

PubMed

Nogueira, Luísa; Quatrehomme, Gérald; Bertrand, Marie-France; Rallon, Christophe; Ceinos, Romain; du Jardin, Philippe; Adalian, Pascal; Alunni, Véronique

2017-03-01

This experimental study examined the lesions produced by a hatchet on human bones (tibiae). A total of 30 lesions were produced and examined macroscopically (naked eye) and by stereomicroscopy. 13 of them were also analyzed using scanning electron microscopy. The general shape of the lesion, both edges, both walls, the kerf floor and the extremities were described. The length and maximum width of the lesions were also recorded. The microscopic analysis of the lesions led to the description of a sharp-blunt mechanism. Specific criteria were identified (lateral pushing back, fragmentation of the upraising, fossa dug laterally to the edge and vertical striae) enabling the forensic expert to conclude that a hacking instrument was used. These criteria are easily identifiable using scanning electron microscopy, but can also be observed with stereomicroscopy. Overall, lateral pushing back and vertical striae visible using stereomicroscopy and scanning electron microscopy signal the use of a hacking tool.

General criteria for the validity of the Buckingham-Darcy Flow Law

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sposito, G.

A detailed, first-principles study is undertaken on the exact equation of linear momentum balance for water in an unsaturated soil. An approximate momentum balance equation (Raats and Klute) demonstrates that the flow of water through a rigid, homogeneous, isotropic, unsaturated soil will obey the Buckingham-Darcy Law within 10/sup -12/ to 10/sup -5/ sec after a gradient in the total potential of soil water has been applied. The Raats-Klute equation will be accurate if (1) the water mass density and mass flux density vector constitute a complete set of strongly coupled, macroscopic dynamical variables, and (2) the time scale over whichmore » these 2 variables change significantly is much longer than that over which any other dynamic quantities vary. If these 2 conditions are met, then, according to statistical mechanics, the flow of water through unsaturated soil will be described accurately over all macroscopic intervals by the Buckingham-Darcy law.« less

Free-standing 3D polyaniline-CNT/Ni-fiber hybrid electrodes for high-performance supercapacitors.

PubMed

Li, Yuan; Fang, Yuzhu; Liu, Hong; Wu, Xiaoming; Lu, Yong

2012-04-28

Free-standing 3D macroscopic polyaniline (PANi)-carbon nanotube (CNT)-nickel fiber hybrids have been developed, and they deliver high specific capacitance (725 F g(-1) at 0.5 A g(-1)) and high energy density at high rates (~22 W h kg(-1) at 2000 W kg(-1), based on total electrode mass) with good cyclability. This journal is © The Royal Society of Chemistry 2012

Protein-protein interactions within photosystem II under photoprotection: the synergy between CP29 minor antenna, subunit S (PsbS) and zeaxanthin at all-atom resolution.

PubMed

Daskalakis, Vangelis

2018-05-07

The assembly and disassembly of protein complexes within cells are crucial life-sustaining processes. In photosystem II (PSII) of higher plants, there is a delicate yet obscure balance between light harvesting and photo-protection under fluctuating light conditions, that involves protein-protein complexes. Recent breakthroughs in molecular dynamics (MD) simulations are combined with new approaches herein to provide structural and energetic insight into such a complex between the CP29 minor antenna and the PSII subunit S (PsbS). The microscopic model involves extensive sampling of bound and dissociated states at atomic resolution in the presence of photo-protective zeaxanthin (Zea), and reveals well defined protein-protein cross-sections. The complex is placed within PSII, and macroscopic connections are emerging (PsbS-CP29-CP24-CP47) along the energy transfer pathways from the antenna to the PSII core. These connections explain macroscopic observations in the literature, while the previously obscured atomic scale details are now revealed. The implications of these findings are discussed in the context of the Non-Photochemical Quenching (NPQ) of chlorophyll fluorescence, the down-regulatory mechanism of photosynthesis, that enables the protection of PSII against excess excitation load. Zea is found at the PsbS-CP29 cross-section and a pH-dependent equilibrium between PsbS dimer/monomers and the PsbS-CP29 dissociation/association is identified as the target for engineering tolerant plants with increased crop and biomass yields. Finally, the new MD based approaches can be used to probe protein-protein interactions in general, and the PSII structure provided can initiate large scale molecular simulations of the photosynthetic apparatus, under NPQ conditions.

Solvable Quantum Macroscopic Motions and Decoherence Mechanisms in Quantum Mechanics on Nonstandard Space

NASA Technical Reports Server (NTRS)

Kobayashi, Tsunehiro

1996-01-01

Quantum macroscopic motions are investigated in the scheme consisting of N-number of harmonic oscillators in terms of ultra-power representations of nonstandard analysis. Decoherence is derived from the large internal degrees of freedom of macroscopic matters.

Template-based preparation of free-standing semiconducting polymeric nanorod arrays on conductive substrates.

PubMed

Haberkorn, Niko; Weber, Stefan A L; Berger, Rüdiger; Theato, Patrick

2010-06-01

We describe the synthesis and characterization of a cross-linkable siloxane-derivatized tetraphenylbenzidine (DTMS-TPD), which was used for the fabrication of semiconducting highly ordered nanorod arrays on conductive indium tin oxide or Pt-coated substrates. The stepwise process allow fabricating of macroscopic areas of well-ordered free-standing nanorod arrays, which feature a high resistance against organic solvents, semiconducting properties and a good adhesion to the substrate. Thin films of the TPD derivate with good hole-conducting properties could be prepared by cross-linking and covalently attaching to hydroxylated substrates utilizing an initiator-free thermal curing at 160 degrees C. The nanorod arrays composed of cross-linked DTMS-TPD were fabricated by an anodic aluminum oxide (AAO) template approach. Furthermore, the nanorod arrays were investigated by a recently introduced method allowing to probe local conductivity on fragile structures. It revealed that more than 98% of the nanorods exhibit electrical conductance and consequently feature a good electrical contact to the substrate. The prepared nanorod arrays have the potential to find application in the fabrication of multilayered device architectures for building well-ordered bulk-heterojunction solar cells.

Study of the microstructure and mechanical properties of white clam shell.

PubMed

Liang, Yunhong; Zhao, Qian; Li, Xiujuan; Zhang, Zhihui; Ren, Luquan

2016-08-01

The microstructure and mechanical properties of white clam shell were investigated, respectively. It can be divided into horny layer, prismatic layer and nacreous layer. Crossed-lamellar structure was the microstructural characteristic. The extension direction of lamellae in prismatic layer was different from that in nacreous layer, which formed an angle on the interface between prismatic layer and nacreous layer. The phase component of three layers was CaCO3 with crystallization morphology of aragonite, which confirmed the crossed-lamellar structural characteristic. White calm shell exhibited perfect mechanical properties. The microhardness values of three layers were 273HV, 240HV and 300HV, respectively. The average values of flexure and compression strength were 110.2MPa and 80.1MPa, respectively. The macroscopical cracks crossed the lamellae and finally terminated within the length range of about 80μm. It was the microstructure characteristics, the angle on the interface between prismatic and nacreous layer and the hardness diversity among the different layers that enhanced mechanical properties of white calm shell. Copyright © 2016 Elsevier Ltd. All rights reserved.

Cross-protection of a new type 2 porcine reproductive and respiratory syndrome virus (PRRSV) modified live vaccine (Fostera PRRS) against heterologous type 1 PRRSV challenge in growing pigs.

PubMed

Park, Changhoon; Choi, Kyuhyung; Jeong, Jiwoon; Chae, Chanhee

2015-05-15

The objective of the present study was to determine the cross-protection of a new type 2 porcine reproductive and respiratory syndrome virus (PRRSV) modified live vaccine against heterologous type 1 PRRSV challenge in growing pigs. The mean rectal temperature and respiratory score was significantly (P<0.05) lower in vaccinated challenged pigs than in unvaccinated challenged pigs. Vaccination of pigs with type 2 PRRSV reduced the levels of type 1 PRRSV viremia after challenge with type 1 PRRSV. Vaccinated challenged pigs had significantly (P<0.05) higher frequency of interferon-γ secreting cells and lower levels of interleukin-10 compared to unvaccinated challenged pigs. Vaccination of pigs with the type 2 PRRSV effectively reduced the macroscopic and microscopic lung lesion and the type 1 PRRSV antigens within lung lesions in vaccinated challenged pigs. This study demonstrates partial cross-protection of a new type 2 PRRSV modified live vaccine against heterologous type 1 PRRSV challenge in growing pigs. Copyright © 2015 Elsevier B.V. All rights reserved.

Quantum Analogies in the Interaction between Acoustic Waves and Bubble Clouds

NASA Astrophysics Data System (ADS)

Parrales, Miguel A.; Rodriguez-Rodriguez, Javier

2014-11-01

Analogies between quantum mechanical and acoustical propagation phenomena have a great interest in academic research due to their ability to shed light on some complex quantum effects, which are impossible to visualize directly in the macroscopic world. In this talk, we describe a number of these analogies concerning the acoustic behavior of bubble clouds. Firstly, we show that the structure of the collective oscillation modes of a spherical bubble cloud resembles that of the atomic orbitals of a hydrogen atom. Secondly, we present an analogy between some perturbation methods used in quantum-electrodynamics and the computation of the acoustic response of the randomly distributed bubble cloud by considering the contribution to the total scattered pressure of the multiple scattering paths that take place inside the clouds. As an application of this analogy, we obtain the scattering cross-section of a diluted cloud, which remarkably mimics the quantum scattering of an neutron wave when passing through an atomic nucleus. Finally, we numerically reproduce the behavior of an electron in a covalent bond between two hydrogen atoms by simulating the acoustic wave propagation through two neighboring spherical bubble assemblages. Funded by the Spanish Ministry of Economy and Competitiveness through Grants DPI2011-28356-C03-01 and DPI2011-28356-C03-02.

Discrepancy between endoscopic forceps biopsy and endoscopic resection in gastric epithelial neoplasia.

PubMed

Lim, Hyun; Jung, Hwoon-Yong; Park, Young Soo; Na, Hee Kyong; Ahn, Ji Yong; Choi, Ji Young; Lee, Jeong Hoon; Kim, Mi-Young; Choi, Kwi-Sook; Kim, Do Hoon; Choi, Kee Don; Song, Ho June; Lee, Gin Hyug; Kim, Jin-Ho

2014-04-01

Endoscopic forceps biopsy (EFB) is a major diagnostic procedure for gastric epithelial neoplasia (GEN). However, discrepancy between the result of EFB and endoscopic resection (ER) is not uncommon. Thus, there is controversy over whether specimens obtained by EFB are optimal for diagnosis of GEN. We investigated the discrepancy between EFB and ER in the diagnosis of GEN. A total of 1,850 GEN cases were histologically diagnosed with EFB, including 954 low-grade dysplasias (LGDs), 315 high-grade dysplasias (HGDs), and 581 carcinomas. Following diagnosis with EFB, all patients were treated with ER. We retrospectively reviewed the pathologic findings and patient characteristics and analyzed predictors for the discrepancy between the two procedures (largest diameter, number of biopsy fragments, number of biopsy fragments/largest diameter, location, macroscopic type, color, surface unevenness, and erosion). The overall discrepancy rate between EFB and ER was 31.7 % (587/1,850). Among the discordant group, 440 (23.9 %) cases showed a higher grade of disease after ER; 229 of the 954 LGDs (24.0 %) were diagnosed as HGD or carcinoma, 166 of the 315 HGDs (52.7 %) as carcinoma, and 45 of the 581 differentiated carcinomas (7.7 %) as undifferentiated carcinoma. In the LGD group with EFB, the largest diameter (≥1.8 cm; P < 0.001), surface unevenness (P = 0.014), and depressed macroscopic type (P < 0.001) were factors associated with discrepancy. In the carcinoma group with EFB, flat macroscopic type (P = 0.043) was the only significant factor. In the HGD group with EFB, there were no significant factors for discrepancy. EFB can be insufficient for diagnosing GENs, and ER can be considered not only as treatment but also as a diagnostic modality in GEN. It is especially pertinent to all cases of HGD regardless of their endoscopic features and to cases of LGDs with the largest lesion diameter ≥1.8 cm, surface unevenness, or a depressed macroscopic type.

Macroscopic appearance of Type IV and giant Type III is a high risk for a poor prognosis in pathological stage II/III advanced gastric cancer with postoperative adjuvant chemotherapy

PubMed Central

Yamashita, Keishi; Ema, Akira; Hosoda, Kei; Mieno, Hiroaki; Moriya, Hiromitsu; Katada, Natsuya; Watanabe, Masahiko

2017-01-01

AIM To evaluate whether a high risk macroscopic appearance (Type IV and giant Type III) is associated with a dismal prognosis after curative surgery, because its prognostic relevance remains elusive in pathological stage II/III (pStage II/III) gastric cancer. METHODS One hundred and seventy-two advanced gastric cancer (defined as pT2 or beyond) patients with pStage II/III who underwent curative surgery plus adjuvant S1 chemotherapy were evaluated, and the prognostic relevance of a high-risk macroscopic appearance was examined. RESULTS Advanced gastric cancers with a high-risk macroscopic appearance were retrospectively identified by preoperative recorded images. A high-risk macroscopic appearance showed a significantly worse relapse free survival (RFS) (35.7%) and overall survival (OS) (34%) than an average risk appearance (P = 0.0003 and P < 0.0001, respectively). A high-risk macroscopic appearance was significantly associated with the 13th Japanese Gastric Cancer Association (JGCA) pT (P = 0.01), but not with the 13th JGCA pN. On univariate analysis for RFS and OS, prognostic factors included 13th JGCA pStage (P < 0.0001) and other clinicopathological factors including macroscopic appearance. A multivariate Cox proportional hazards model for univariate prognostic factors identified high-risk macroscopic appearance (P = 0.036, HR = 2.29 for RFS and P = 0.021, HR = 2.74 for OS) as an independent prognostic indicator. CONCLUSION A high-risk macroscopic appearance was associated with a poor prognosis, and it could be a prognostic factor independent of 13th JGCA stage in pStage II/III advanced gastric cancer. PMID:28451064

The severity of the long head biceps tendinopathy in patients with chronic rotator cuff tears: macroscopic versus microscopic results.

PubMed

Wu, Po-Ting; Jou, I-Ming; Yang, Cheng-Chang; Lin, Chii-Jeng; Yang, Chyun-Yu; Su, Fong-Chin; Su, Wei-Ren

2014-08-01

This study investigated the histopathology of the long head of biceps (LHB) tendon and correlated the findings with the macroscopic appearances of the LHB and the size of rotator cuff tears (RCTs) in patients with chronic RCTs. We compared biopsy specimens from LHBs in 34 patients with chronic RCTs and grossly normal LHBs in 8 patients undergoing shoulder hemiarthroplasty (controls). Duration of preoperative symptoms, the severity of RCTs, and macroscopic appearance of LHBs were recorded, classified, and compared with the histologic grading and apoptosis index of terminal deoxynucleotide transferase-mediated biotin-deoxy uridine triphosphate nick-end labeling (TUNEL) assays of LHBs. In the RCT group, there were 8 partial-thickness tears with 5 macroscopic LHB lesions, 12 full-thickness tears with 8 macroscopic LHB lesions, and 14 massive tears with 13 macroscopic LHB lesions. There were 6 LHB subluxations. However, the macroscopic grading and the symptom duration were not correlated with the severity of the histology. In patients with massive tears, no matter what the macroscopic appearance of the LHB, the proportion of end-stage (grade 4) histologic LHB tendinopathy significantly increased (85.7%, P < .05) compared with patients with other types of RCTs. There was a consistently high incidence of advanced LHB histology (grade 3 or higher) in each classification of RCTs (75.0%-100.0%). The 8 patients in the control group showed milder histopathology (grade 1 or 2). The apoptosis index significantly increased as the tendinopathy progressed (P < .05). The macroscopic pathology of LHB may not fully reflect the severity of tendinopathy, and the coexisting size of RCTs plays a role in the severity of LHB tendinopathy. Copyright © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

Hauser-Feshbach fission fragment de-excitation with calculated macroscopic-microscopic mass yields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jaffke, Patrick John; Talou, Patrick; Sierk, Arnold John

The Hauser-Feshbach statistical model is applied to the de-excitation of primary fission fragments using input mass yields calculated with macroscopic-microscopic models of the potential energy surface. We test the sensitivity of the prompt fission observables to the input mass yields for two important reactions, 235U (n th, f) and 239Pu (n th, f) , for which good experimental data exist. General traits of the mass yields, such as the location of the peaks and their widths, can impact both the prompt neutron and γ-ray multiplicities, as well as their spectra. Specifically, we use several mass yields to determine a linear correlation between the calculated prompt neutron multiplicitymore » $$\\bar{v}$$ and the average heavy-fragment mass $$\\langle$$A h$$\\rangle$$ of the input mass yields ∂$$\\bar{v}$$/∂ $$\\langle$$A h$$\\rangle$$ = ± 0.1 (n / f )/u . The mass peak width influences the correlation between the total kinetic energy of the fission fragments and the total number of prompt neutrons emitted, $$\\bar{v}_T$$ ( TKE ) . Finally, typical biases on prompt particle observables from using calculated mass yields instead of experimental ones are δ$$\\bar{v}$$ = 4 % for the average prompt neutron multiplicity, δ$$\\overline{M}_γ$$ = 1% for the average prompt γ-ray multiplicity, δ$$\\bar{ε}$$ $$LAB\\atop{n}$$ = 1 % for the average outgoing neutron energy, δ$$\\bar{ε}_γ$$ = 1 % for the average γ-ray energy, and δ $$\\langle$$TKE$$\\rangle$$ = 0.4 % for the average total kinetic energy of the fission fragments.« less

Hauser-Feshbach fission fragment de-excitation with calculated macroscopic-microscopic mass yields

DOE PAGES

Jaffke, Patrick John; Talou, Patrick; Sierk, Arnold John; ...

2018-03-15

The Hauser-Feshbach statistical model is applied to the de-excitation of primary fission fragments using input mass yields calculated with macroscopic-microscopic models of the potential energy surface. We test the sensitivity of the prompt fission observables to the input mass yields for two important reactions, 235U (n th, f) and 239Pu (n th, f) , for which good experimental data exist. General traits of the mass yields, such as the location of the peaks and their widths, can impact both the prompt neutron and γ-ray multiplicities, as well as their spectra. Specifically, we use several mass yields to determine a linear correlation between the calculated prompt neutron multiplicitymore » $$\\bar{v}$$ and the average heavy-fragment mass $$\\langle$$A h$$\\rangle$$ of the input mass yields ∂$$\\bar{v}$$/∂ $$\\langle$$A h$$\\rangle$$ = ± 0.1 (n / f )/u . The mass peak width influences the correlation between the total kinetic energy of the fission fragments and the total number of prompt neutrons emitted, $$\\bar{v}_T$$ ( TKE ) . Finally, typical biases on prompt particle observables from using calculated mass yields instead of experimental ones are δ$$\\bar{v}$$ = 4 % for the average prompt neutron multiplicity, δ$$\\overline{M}_γ$$ = 1% for the average prompt γ-ray multiplicity, δ$$\\bar{ε}$$ $$LAB\\atop{n}$$ = 1 % for the average outgoing neutron energy, δ$$\\bar{ε}_γ$$ = 1 % for the average γ-ray energy, and δ $$\\langle$$TKE$$\\rangle$$ = 0.4 % for the average total kinetic energy of the fission fragments.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, Suvam; Naghma, Rahla; Kaur, Jaspreet

The total and ionization cross sections for electron scattering by benzene, halobenzenes, toluene, aniline, and phenol are reported over a wide energy domain. The multi-scattering centre spherical complex optical potential method has been employed to find the total elastic and inelastic cross sections. The total ionization cross section is estimated from total inelastic cross section using the complex scattering potential-ionization contribution method. In the present article, the first theoretical calculations for electron impact total and ionization cross section have been performed for most of the targets having numerous practical applications. A reasonable agreement is obtained compared to existing experimental observationsmore » for all the targets reported here, especially for the total cross section.« less

Macroscopic modeling of freeway traffic using an artificial neural network

DOT National Transportation Integrated Search

1997-01-01

Traffic flow on freeways is a complex process that often is described by a set of highly nonlinear, dynamic equations in the form of a macroscopic traffic flow model. However, some of the existing macroscopic models have been found to exhibit instabi...

Uncovering low dimensional macroscopic chaotic dynamics of large finite size complex systems

NASA Astrophysics Data System (ADS)

Skardal, Per Sebastian; Restrepo, Juan G.; Ott, Edward

2017-08-01

In the last decade, it has been shown that a large class of phase oscillator models admit low dimensional descriptions for the macroscopic system dynamics in the limit of an infinite number N of oscillators. The question of whether the macroscopic dynamics of other similar systems also have a low dimensional description in the infinite N limit has, however, remained elusive. In this paper, we show how techniques originally designed to analyze noisy experimental chaotic time series can be used to identify effective low dimensional macroscopic descriptions from simulations with a finite number of elements. We illustrate and verify the effectiveness of our approach by applying it to the dynamics of an ensemble of globally coupled Landau-Stuart oscillators for which we demonstrate low dimensional macroscopic chaotic behavior with an effective 4-dimensional description. By using this description, we show that one can calculate dynamical invariants such as Lyapunov exponents and attractor dimensions. One could also use the reconstruction to generate short-term predictions of the macroscopic dynamics.

In situ studies of velocity in fractured crystalline rocks.

USGS Publications Warehouse

Moos, D.; Zoback, M.D.

1983-01-01

A study of the effects of macroscopic fractures on P and S wave velocities has been conducted in four wells drilled in granitic rock to depths between 0.6 and 1.2km. The effect of macroscopic fractures is to decrease both Vp and Vs and increase Vp/Vs. In wells with a relatively low density of macroscopic fractures, the in situ velocity is similar to that of saturated core samples under confining pressure in the laboratory, and there is a clear correlation between zones with macroscopic fractures and anomalously low velocities. In wells with numerous macroscopic fractures, the in situ velocity is lower than that of intact samples under pressure, and there is a correlation between the rate at which in situ velocity increases with depth and the rate at which the velocity of laboratory samples increases with pressure. Differences in in situ P wave velocity between wells cannot be explained solely by differences in the degree of macroscopic fracturing, thus emphasizing the importance of composition and microcracks on velocity.-from Authors

Latitudinal and stock-specific variation in size- and age-at-maturity of female winter flounder, Pseudopleuronectes americanus, as determined with gonad histology

NASA Astrophysics Data System (ADS)

McBride, Richard S.; Wuenschel, Mark J.; Nitschke, Paul; Thornton, Grace; King, Jeremy R.

2013-01-01

Female winter flounder were examined using gonad histology to determine the adequacy of routine macroscopic maturity classification methods and to determine the spatial variation in size and age of maturity in U.S. waters. Sampling occurred in spring and autumn, which was adequate to collect immature, mature, spawning-active, and non-active females. Females were collected in coastal waters from Delaware Bay, USA, to the Scotian Shelf, Canada, including in Long Island Sound and on Georges Bank, which covered all U.S. stock areas. Mature fish spawned in spring, when gonads comprised up to 30% of the total body weight. Direct comparisons of maturity assignment by macroscopic versus microscopic methods demonstrated that both schemes are compatible, but the more cost-effective macroscopic method had trouble distinguishing larger immature from smaller resting females. Spatial comparisons, using gonad histology only, supported the existence of three stocks in U.S. waters, but also revealed significant variation in age at maturity within the two coastal stocks. Age-at-maturity was more variable than size-at-maturity, which is consistent with known stock-specific patterns of growth rates and a postulated life history tradeoff to delay maturity until a size threshold is reached. The within-stock variation in median age at maturity, about one year for coastal stocks, recommends further investigation of using static, stock-specific maturity ogives to calculate reference points for management.

Superconductivity-induced macroscopic resonant tunneling.

PubMed

Goorden, M C; Jacquod, Ph; Weiss, J

2008-02-15

We show analytically and by numerical simulations that the conductance through pi-biased chaotic Josephson junctions is enhanced by several orders of magnitude in the short-wavelength regime. We identify the mechanism behind this effect as macroscopic resonant tunneling through a macroscopic number of low-energy quasidegenerate Andreev levels.

Saturn's E Ring in Ultraviolet Light

NASA Technical Reports Server (NTRS)

2002-01-01

Visible from Earth only at times of ring plane crossing, Saturn's tenuous E Ring was discovered during the 1966 crossings and imaged again in 1980. From these observations, its color is known to be distinctively blue. The E Ring was captured in ultraviolet light for the first time in this image taken with HST's Wide Field and Planetary Camera on 9 August 1995. Five individual images taken with a broadband 3000 A filter were combined, amounting to a total exposure time of 2200 sec. Shorter exposure images were also obtained with blue, red and infrared filters in order to characterize the ring's color. The peak brightness of the E Ring occurs at 3.9 Saturn radii (235,000 km), coinciding with the orbit of Enceladus. In the HST images it can be traced out to a maximum distance of approximately 8 Rs (480,000 km). The vertical thickness of the ring, on the other hand, is smallest at Enceladus' orbit, with the ring puffing up noticeably at larger distances to 15,000 km or more thick. Also visible in this image, between the E Ring and the overexposed outermost part of the main rings near the lower edge of the frame, is the tenuous, thin, 6000 km-wide G Ring at 2.8 Rs (170,000 km). This is among the first earth-based observations of the G Ring, which was discovered by the Pioneer 11 spacecraft in 1979. Noticeably thinner than the E Ring and more neutral in color, the G Ring is thought to be composed of larger, macroscopic particles, and to pose a significant hazard to spacecraft. The faint diagonal band in the lower right part of the image is due to diffracted light from the heavily-overexposed planet. Credit: Phil Nicholson (Cornell University), Mark Showalter (NASA-Ames/Stanford) and NASA

A comparison of total reaction cross section models used in particle and heavy ion transport codes

NASA Astrophysics Data System (ADS)

Sihver, Lembit; Lantz, M.; Takechi, M.; Kohama, A.; Ferrari, A.; Cerutti, F.; Sato, T.

To be able to calculate the nucleon-nucleus and nucleus-nucleus total reaction cross sections with precision is very important for studies of basic nuclear properties, e.g. nuclear structure. This is also of importance for particle and heavy ion transport calculations because, in all particle and heavy ion transport codes, the probability function that a projectile particle will collide within a certain distance x in the matter depends on the total reaction cross sections. Furthermore, the total reaction cross sections will also scale the calculated partial fragmentation cross sections. It is therefore crucial that accurate total reaction cross section models are used in the transport calculations. In this paper, different models for calculating nucleon-nucleus and nucleus-nucleus total reaction cross sections are compared and discussed.

Ovine echinococcosis I. Immunological diagnosis by enzyme immunoassay.

PubMed

Gatti, Antonio; Alvarez, Angela Rosa; Araya, Daniel; Mancini, Sergio; Herrero, Eduardo; Santillan, Graciela; Larrieu, Edmundo

2007-01-31

Immunodiagnosis in sheep presents problems of sensitivity and specificity, limiting its applicability in surveillance systems. The objective of this study was to develop a sensitive, specific and accessible technique for diagnosing cystic echinococcosis in naturally infected sheep and to evaluate the validity of necropsy as a reference test. A total of 247 sheep were studied at slaughterhouses, confirming the parasitological diagnosis with histology. Serum was processed with enzyme immunoassay (EIA) using three antigen preparations: total hydatid liquid (LHT), purified fraction of LHT (S2B) and purified lipoprotein (B). Western Blot (WB) was used as a control. EIA proved effective for differentiating Echinococcus granulosus from larval stage of Taenia hydatigena and intestinal cestodes in all three antigen preparations. Serums from macroscopically negative sheep were reactive to EIA and positive with WB. In the whole flock, sensitivity was 89.2% for LHT, 80.0% for S2B and 86.4% for B. Sensitivity in lambs was 78.6% for LHT, 75.0% for S2B and 64.3% for B. Macroscopic diagnosis at the time of slaughter was found to have limitations as a reference test for immunodiagnosis of cystic equinococcosis in sheep, so it was necessary to include histology and WB as reference tests. LHT was the antigen preparation of greatest value and EIA proved to be a sensitive and specific technique, adequate for surveillance systems and for evaluating control programmes.

Nothing new under the heavens: MIH in the past?

PubMed

Ogden, A R; Pinhasi, R; White, W J

2008-12-01

This was to study an archaeological population of subadult teeth in 17th and 18th century skeletal material from a London (England) cemetery for enamel defects including molar-incisor-hypomineralisation (MIH). Dentitions of 45 sub-adults were examined using standard macroscopic methods and systematically recorded. A total of 557 teeth were examined with a *5 lens and photographed. Ages of the individuals were estimated from their dental crown and root development stages and not from charts that combine tooth eruption with development stages. The dental age of the individual and the approximate age of onset of enamel defects was then calculated on the basis of the chronological sequence of incremental deposition and calcification of the enamel matrix. Affected enamel was graded macroscopically as: - Mild: <30% of the tooth's enamel surface area visibly disrupted (this encompasses the entire range reported in most other studies), Moderate: 31-49% of the tooth's enamel surface area visibly disrupted and Severe: >50% of the tooth's enamel surface area visibly disrupted. Of the total number of individuals 41 (93.2%) showed signs of enamel developmental dysplasia or MIH, 28 of them showing moderate or severe lesions of molars, primary or permanent (63.6% of the sample). Incisors and canines, though surviving much less often, showed episodes of linear hypoplasia. The extensive lesions seen on many of the molars displayed cuspal enamel hypoplasia (CEH). Many of these teeth also exhibited Molar Incisal Hypomineralisation (MIH).

Terahertz Science and Technology of Macroscopically Aligned Carbon Nanotube Films

NASA Astrophysics Data System (ADS)

Kono, Junichiro

One of the outstanding challenges in nanotechnology is how to assemble individual nano-objects into macroscopic architectures while preserving their extraordinary properties. For example, the one-dimensional character of electrons in individual carbon nanotubes leads to extremely anisotropic transport, optical, and magnetic phenomena, but their macroscopic manifestations have been limited. Here, we describe methods for preparing macroscopic films, sheets, and fibers of highly aligned carbon nanotubes and their applications to basic and applied terahertz studies. Sufficiently thick films act as ideal terahertz polarizers, and appropriately doped films operate as polarization-sensitive, flexible, powerless, and ultra-broadband detectors. Together with recently developed chirality enrichment methods, these developments will ultimately allow us to study dynamic conductivities of interacting one-dimensional electrons in macroscopic single crystals of single-chirality single-wall carbon nanotubes.

The use of multi representative learning materials: definitive, macroscopic, microscopic, symbolic, and practice in analyzing students’ concept understanding

NASA Astrophysics Data System (ADS)

Susilaningsih, E.; Wulandari, C.; Supartono; Kasmui; Alighiri, D.

2018-03-01

This research aims to compose learning material which contains definitive macroscopic, microscopic and symbolic to analyze students’ conceptual understanding in acid-base learning materials. This research was conducted in eleven grade, natural science class, senior high school 1 (SMAN 1) Karangtengah, Demak province, Indonesia as the low level of students’ conceptual understanding and the high level of students’ misconception. The data collecting technique is by test to assess the cognitive aspect, questionnaire to assess students’ responses to multi representative learning materials (definitive, macroscopic, microscopic, symbolic), and observation to assess students’ macroscopic aspects. Three validators validate the multi-representative learning materials (definitive, macroscopic, microscopic, symbolic). The results of the research show that the multi-representative learning materials (definitive, macroscopic, microscopes, symbolic) being used is valid in the average score 62 of 75. The data is analyzed using the descriptive qualitative method. The results of the research show that 72.934 % students understand, 7.977 % less understand, 8.831 % do not understand, and 10.256 % misconception. In comparison, the second experiment class shows 54.970 % students understand, 5.263% less understand, 11.988 % do not understand, 27.777 % misconception. In conclusion, the application of multi representative learning materials (definitive, macroscopic, microscopic, symbolic) can be used to analyze the students’ understanding of acid-base materials.

Use of thermal neutron reflection method for chemical analysis of bulk samples

NASA Astrophysics Data System (ADS)

Papp, A.; Csikai, J.

2014-09-01

Microscopic, σβ, and macroscopic, Σβ, reflection cross-sections of thermal neutrons averaged over bulk samples as a function of thickness (z) are given. The σβ values are additive even for bulk samples in the z=0.5-8 cm interval and so the σβmol(z) function could be given for hydrogenous substances, including some illicit drugs, explosives and hiding materials of ~1000 cm3 dimensions. The calculated excess counts agree with the measured R(z) values. For the identification of concealed objects and chemical analysis of bulky samples, different neutron methods need to be used simultaneously.

Focal Conic Stacking in Smectic A Liquid Crystals: Smectic Flower and Apollonius Tiling

PubMed Central

Meyer, Claire; Cunff, Loic Le; Belloul, Malika; Foyart, Guillaume

2009-01-01

We investigate two different textures of smectic A liquid crystals. These textures are particularly symmetric when they are observed at crossed polars optical microscopy. For both textures, a model has been made in order to examine the link between the defective macroscopic texture and the microscopic disposition of the layers. We present in particular in the case of some hexagonal tiling of circles (similar to the Apollonius tiling) some numeric simulation in order to visualize the smectic layers. We discuss of the nature of the smectic layers, which permit to assure their continuity from one focal conic domain to another adjacent one.

Waveguide image-slicers for ultrahigh resolution spectroscopy

NASA Astrophysics Data System (ADS)

Beckert, Erik; Strassmeier, Klaus G.; Woche, Manfred; Eberhardt, Ramona; Tünnermann, Andreas; Andersen, Michael

2008-07-01

Waveguide image-slicer prototypes with resolutions up to 310.000 for the fiber fed PEPSI echelle spectrograph at the LBT and single waveguide thicknesses of down to 30 μm have been manufactured. The waveguides were macroscopically prepared, stacked up to an order of 7 and thinned back to square stack cross sections. A high filling ratio was achieved by realizing homogenous adhesive gaps of 4.6 μm, using index matching adhesives for TIR within the waveguides. The image-slicer stacks can be used in immersion mode and are miniaturized to be implemented in a set of four, measurements indicate an overall efficiency of above 80% for them.

VENTURE: a code block for solving multigroup neutronics problems applying the finite-difference diffusion-theory approximation to neutron transport

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vondy, D.R.; Fowler, T.B.; Cunningham, G.W.

1975-10-01

The computer code block VENTURE, designed to solve multigroup neutronics problems with application of the finite-difference diffusion-theory approximation to neutron transport (or alternatively simple P$sub 1$) in up to three- dimensional geometry is described. A variety of types of problems may be solved: the usual eigenvalue problem, a direct criticality search on the buckling, on a reciprocal velocity absorber (prompt mode), or on nuclide concentrations, or an indirect criticality search on nuclide concentrations, or on dimensions. First- order perturbation analysis capability is available at the macroscopic cross section level. (auth)

Inelastic scattering of 61 MeV protons by pb-207

NASA Technical Reports Server (NTRS)

Owais, M.

1976-01-01

Differential cross sections for the excitation of the first four neutron-hole states and the doublet at 2.61 MeV by 61.2 MeV protons were measured. The data are analyzed in terms of both a purely collective model description and a microscopic model supplemented by macroscopic core polarization. A realistic two-body interaction is used and knock-on amplitudes are included. Core polarization is found to be important but represents a relatively smaller contribution than in most nuclei previously studied. A parallel analysis of similar data at lower proton bombarding energies reveals a surprisingly strong energy dependence of the reaction mechanisms.

Total cross sections for positrons scattered elastically from helium based on new measurements of total ionization cross sections

NASA Technical Reports Server (NTRS)

Diana, L. M.; Chaplin, R. L.; Brooks, D. L.; Adams, J. T.; Reyna, L. K.

1990-01-01

An improved technique is presented for employing the 2.3m spectrometer to measure total ionization cross sections, Q sub ion, for positrons incident on He. The new ionization cross section agree with the values reported earlier. Estimates are also presented of total elastic scattering cross section, Q sub el, obtained by subtracting from total scattering cross sections, Q sub tot, reported in the literature, the Q sub ion and Q sub Ps (total positronium formation cross sections) and total excitation cross sections, Q sub ex, published by another researcher. The Q sub ion and Q sub el measured with the 3m high resolution time-of-flight spectrometer for 54.9eV positrons are in accord with the results from the 2.3m spectrometer. The ionization cross sections are in fair agreement with theory tending for the most part to be higher, especially at 76.3 and 88.5eV. The elastic cross section agree quite well with theory to the vicinity of 50eV, but at 60eV and above the experimental elastic cross sections climb to and remain at about 0.30 pi a sub o sq while the theoretical values steadily decrease.

Macroscopic modeling of heat and water vapor transfer with phase change in dry snow based on an upscaling method: Influence of air convection

NASA Astrophysics Data System (ADS)

Calonne, N.; Geindreau, C.; Flin, F.

2015-12-01

At the microscopic scale, i.e., pore scale, dry snow metamorphism is mainly driven by the heat and water vapor transfer and the sublimation-deposition process at the ice-air interface. Up to now, the description of these phenomena at the macroscopic scale, i.e., snow layer scale, in the snowpack models has been proposed in a phenomenological way. Here we used an upscaling method, namely, the homogenization of multiple-scale expansions, to derive theoretically the macroscopic equivalent modeling of heat and vapor transfer through a snow layer from the physics at the pore scale. The physical phenomena under consideration are steady state air flow, heat transfer by conduction and convection, water vapor transfer by diffusion and convection, and phase change (sublimation and deposition). We derived three different macroscopic models depending on the intensity of the air flow considered at the pore scale, i.e., on the order of magnitude of the pore Reynolds number and the Péclet numbers: (A) pure diffusion, (B) diffusion and moderate convection (Darcy's law), and (C) strong convection (nonlinear flow). The formulation of the models includes the exact expression of the macroscopic properties (effective thermal conductivity, effective vapor diffusion coefficient, and intrinsic permeability) and of the macroscopic source terms of heat and vapor arising from the phase change at the pore scale. Such definitions can be used to compute macroscopic snow properties from 3-D descriptions of snow microstructures. Finally, we illustrated the precision and the robustness of the proposed macroscopic models through 2-D numerical simulations.

Nonlocal interferometry with macroscopic coherent states and its application to quantum communications

NASA Astrophysics Data System (ADS)

Kirby, Brian

Macroscopic quantum effects are of fundamental interest because they help us to understand the quantum-classical boundary, and may also have important practical applications in long-range quantum communications. Specifically we analyze a macroscopic generalization of the Franson interferometer, where violations of Bell's inequality can be observed using phase entangled coherent states created using weak nonlinearities. Furthermore we want to understand how these states, and other macroscopic quantum states, can be applied to secure quantum communications. We find that Bell's inequality can be violated at ranges of roughly 400 km in optical fiber when various unambiguous state discrimination techniques are applied. In addition Monte Carlo simulations suggest that quantum communications schemes based on macroscopic quantum states and random unitary transformations can be potentially secure at long distances. Lastly, we calculate the feasibility of creating the weak nonlinearity needed for the experimental realization of these proposals using metastable xenon in a high finesse cavity. This research suggests that quantum states created using macroscopic coherent states and weak nonlinearities may be a realistic path towards the realization of secure long-range quantum communications.

Monitoring nanoparticle-mediated cellular hyperthermia with a high-sensitivity biosensor

PubMed Central

Mukherjee, Amarnath; Castanares, Mark; Hedayati, Mohammad; Wabler, Michele; Trock, Bruce; Kulkarni, Prakash; Rodriguez, Ronald; Getzenberg, Robert H; DeWeese, Theodore L; Ivkov, Robert; Lupold, Shawn E

2014-01-01

Aim To develop and apply a heat-responsive and secreted reporter assay for comparing cellular response to nanoparticle (NP)- and macroscopic-mediated sublethal hyperthermia. Materials & methods Reporter cells were heated by water bath (macroscopic heating) or iron oxide NPs activated by alternating magnetic fields (nanoscopic heating). Cellular responses to these thermal stresses were measured in the conditioned media by secreted luciferase assay. Results & conclusion Reporter activity was responsive to macroscopic and nanoparticle heating and activity correlated with measured macroscopic thermal dose. Significant cellular responses were observed with NP heating under doses that were insufficient to measurably change the temperature of the system. Under these conditions, the reporter response correlated with proximity to cells loaded with heated nanoparticles. These results suggest that NP and macroscopic hyperthermia may be distinctive under conditions of mild hyperthermia. PMID:24547783

Three-dimensional Fe3O4-graphene macroscopic composites for arsenic and arsenate removal.

PubMed

Guo, Liangqia; Ye, Peirong; Wang, Jing; Fu, Fengfu; Wu, Zujian

2015-11-15

3D graphene macroscopic gel synthesized via self-assembly of GO nanosheets under basic conditions at low temperature is modified with polydopamine and Fe3O4 nanoparticles. The modification of polydopamine can not only strengthen the 3D graphene-based macroscopic architecture but also enhance the loadage and binding ability of Fe3O4 nanoparticles. The synthesized 3D Fe3O4-graphene macroscopic composites are characterized by SEM, XRD, XPS, BET, Raman and magnetic property and used as a versatile adsorbent for sub-ppm concentration of As(III) and As(V) removal from aqueous solutions. The experimental results suggest that the synthesized 3D Fe3O4-graphene macroscopic composites are promising for treating low concentration of arsenic contaminated water. Copyright © 2015 Elsevier B.V. All rights reserved.

Fabrication of elastomeric silk fibers.

PubMed

Bradner, Sarah A; Partlow, Benjamin P; Cebe, Peggy; Omenetto, Fiorenzo G; Kaplan, David L

2017-09-01

Methods to generate fibers from hydrogels, with control over mechanical properties, fiber diameter, and crystallinity, while retaining cytocompatibility and degradability, would expand options for biomaterials. Here, we exploited features of silk fibroin protein for the formation of tunable silk hydrogel fibers. The biological, chemical, and morphological features inherent to silk were combined with elastomeric properties gained through enzymatic crosslinking of the protein. Postprocessing via methanol and autoclaving provided tunable control of fiber features. Mechanical, optical, and chemical analyses demonstrated control of fiber properties by exploiting the physical cross-links, and generating double network hydrogels consisting of chemical and physical cross-links. Structure and chemical analyses revealed crystallinity from 30 to 50%, modulus from 0.5 to 4 MPa, and ultimate strength 1-5 MPa depending on the processing method. Fabrication and postprocessing combined provided fibers with extensibility from 100 to 400% ultimate strain. Fibers strained to 100% exhibited fourth order birefringence, revealing macroscopic orientation driven by chain mobility. The physical cross-links were influenced in part by the drying rate of fabricated materials, where bound water, packing density, and microstructural homogeneity influenced cross-linking efficiency. The ability to generate robust and versatile hydrogel microfibers is desirable for bottom-up assembly of biological tissues and for broader biomaterial applications. © 2017 Wiley Periodicals, Inc.

Macroscopic Innervation of the Dura Mater Covering the Middle Cranial Fossa in Humans Correlated to Neurovascular Headache

PubMed Central

Lee, Shin-Hyo; Hwang, Seung-Jun; Koh, Ki-Seok; Song, Wu-Chul; Han, Sang-Don

2017-01-01

The trigeminovascular system within the cranial dura mater is a possible cause of headaches. The aim of this study is to investigate macroscopically dural innervation around the middle meningeal artery (MMA) in the middle cranial fossa. Forty-four sides of the cranial dura overlying the skull base obtained from 24 human cadavers were stained using Sihler’s method. Overall, the nervus spinosus (NS) from either the maxillary or mandibular trigeminal divisions ran along the lateral wall of the middle meningeal vein rather than that of the MMA. Distinct bundles of the NS running along the course of the frontal branches of the MMA were present in 81.8% of cases (N = 36). Others did not form dominant nerve bundles, instead giving off free nerve endings along the course of the MMA or dural connective tissue. The distribution of these nerve endings was similar to that of the course of the frontal, parietal and petrosal branches of the MMA (11.4%). The others were not restricted to a perivascular plexus, crossing the dural connective tissues far from the MMA (6.8%). These findings indicate that the NS generally travels alongside the course of the frontal branches of the MMA and terminates in the vicinity of the pterion. PMID:29311855

Nanoporous thermosetting polymers.

PubMed

Raman, Vijay I; Palmese, Giuseppe R

2005-02-15

Potential applications of nanoporous thermosetting polymers include polyelectrolytes in fuel cells, separation membranes, adsorption media, and sensors. Design of nanoporous polymers for such applications entails controlling permeability by tailoring pore size, structure, and interface chemistry. Nanoporous thermosetting polymers are often synthesized via free radical mechanisms using solvents that phase separate during polymerization. In this work, a novel technique for the synthesis of nanoporous thermosets is presented that is based on the reactive encapsulation of an inert solvent using step-growth cross-linking polymerization without micro/macroscopic phase separation. The criteria for selecting such a monomer-polymer-solvent system are discussed based on FTIR analysis, observed micro/macroscopic phase separation, and thermodynamics of swelling. Investigation of resulting network pore structures by scanning electron microscopy (SEM) and small-angle X-ray scattering following extraction and supercritical drying using carbon dioxide showed that nanoporous polymeric materials with pore sizes ranging from 1 to 50 nm can be synthesized by varying the solvent content. The differences in the porous morphology of these materials compared to more common free radically polymerized analogues that exhibit phase separation were evident from SEM imaging. Furthermore, it was demonstrated that the chemical activity of the nanoporous materials obtained by our method could be tailored by grafting appropriate functional groups at the pore interface.

Epitaxial Growth of Aligned and Continuous Carbon Nanofibers from Carbon Nanotubes.

PubMed

Lin, Xiaoyang; Zhao, Wei; Zhou, Wenbin; Liu, Peng; Luo, Shu; Wei, Haoming; Yang, Guangzhi; Yang, Junhe; Cui, Jie; Yu, Richeng; Zhang, Lina; Wang, Jiaping; Li, Qunqing; Zhou, Weiya; Zhao, Weisheng; Fan, Shoushan; Jiang, Kaili

2017-02-28

Exploiting the superior properties of nanomaterials at macroscopic scale is a key issue of nanoscience. Different from the integration strategy, "additive synthesis" of macroscopic structures from nanomaterial templates may be a promising choice. In this paper, we report the epitaxial growth of aligned, continuous, and catalyst-free carbon nanofiber thin films from carbon nanotube films. The fabrication process includes thickening of continuous carbon nanotube films by gas-phase pyrolytic carbon deposition and further graphitization of the carbon layer by high-temperature treatment. As-fabricated nanofibers in the film have an "annual ring" cross-section, with a carbon nanotube core and a graphitic periphery, indicating the templated growth mechanism. The absence of a distinct interface between the carbon nanotube template and the graphitic periphery further implies the epitaxial growth mechanism of the fiber. The mechanically robust thin film with tunable fiber diameters from tens of nanometers to several micrometers possesses low density, high electrical conductivity, and high thermal conductivity. Further extension of this fabrication method to enhance carbon nanotube yarns is also demonstrated, resulting in yarns with ∼4-fold increased tensile strength and ∼10-fold increased Young's modulus. The aligned and continuous features of the films together with their outstanding physical and chemical properties would certainly promote the large-scale applications of carbon nanofibers.

Macroscopic Innervation of the Dura Mater Covering the Middle Cranial Fossa in Humans Correlated to Neurovascular Headache.

PubMed

Lee, Shin-Hyo; Hwang, Seung-Jun; Koh, Ki-Seok; Song, Wu-Chul; Han, Sang-Don

2017-01-01

The trigeminovascular system within the cranial dura mater is a possible cause of headaches. The aim of this study is to investigate macroscopically dural innervation around the middle meningeal artery (MMA) in the middle cranial fossa. Forty-four sides of the cranial dura overlying the skull base obtained from 24 human cadavers were stained using Sihler's method. Overall, the nervus spinosus (NS) from either the maxillary or mandibular trigeminal divisions ran along the lateral wall of the middle meningeal vein rather than that of the MMA. Distinct bundles of the NS running along the course of the frontal branches of the MMA were present in 81.8% of cases ( N = 36). Others did not form dominant nerve bundles, instead giving off free nerve endings along the course of the MMA or dural connective tissue. The distribution of these nerve endings was similar to that of the course of the frontal, parietal and petrosal branches of the MMA (11.4%). The others were not restricted to a perivascular plexus, crossing the dural connective tissues far from the MMA (6.8%). These findings indicate that the NS generally travels alongside the course of the frontal branches of the MMA and terminates in the vicinity of the pterion.

Failure analysis of eleven Gates Glidden drills that fractured intraorally during post space preparation. A retrieval analysis study.

PubMed

Al Jabbari, Youssef S; Fournelle, Raymond; Al Taweel, Sara M; Zinelis, Spiros

2017-07-19

The purpose of this study was to determine the failure mechanism of clinically failed Gates Glidden (GG) drills. Eleven retrieved GG drills (sizes #1 to #3) which fractured during root canal preparation were collected and the fracture location was recorded based on macroscopic observation. All fracture surfaces were investigated by a SEM. Then the fractured parts were embedded in acrylic resin and after metallographic preparation, the microstructure and elemental composition was evaluated by SEM and EDS. The Vickers hardness (HV) of all specimens was also determined. Macroscopic examination and SEM analysis showed that the drills failed near the hand piece end by torsional fatigue with fatigue cracks initiating at several locations around the circumference and propagating toward the center. Final fracture followed by a tensile overloading at the central region of cross section. Microstructural analysis, hardness measurements and EDS show that the drills are made of a martensitic stainless steel like AISI 440C. Based on the findings of this study, clinicians should expect fatigue fracture of GG drills that have small size during root canal preparation. Selection of a more fatigue resistant stainless steel alloy and enhancing the instrument design might reduce the incidence of quasi-cleavage fracture on GG drills.

Electron impact scattering study of hypohalous acids HOX (X = F, Cl, Br, I)

NASA Astrophysics Data System (ADS)

Yadav, Hitesh; Bhutadia, Harshad; Prajapati, Dinesh; Desai, Hardik; Vinodkumar, Minaxi; Vinodkumar, P. C.

2018-05-01

In this article we aim to report total cross sections (TCS) QT, total elastic cross sections (Qel), total inelastic cross sections (Qinel) i.e. (total ionizations cross sections (Qion)+total electronic excitation cross sections (Qexc)) from threshold of the target to 5000 eV energy range. We have used a well-defined theoretical methodology Spherical Complex Optical Potential (SCOP) to compute QT, Qel and Qinel and Complex Scattering Potential - ionization contribution (CSP - ic) method to report the (Qion). The cross-sectional data reported here for the Hypohalous Acids is for the first time and the present data can become a guideline for the experimentalist to study these targets.

Generating giant and tunable nonlinearity in a macroscopic mechanical resonator from a single chemical bond

NASA Astrophysics Data System (ADS)

Huang, Pu; Zhou, Jingwei; Zhang, Liang; Hou, Dong; Lin, Shaochun; Deng, Wen; Meng, Chao; Duan, Changkui; Ju, Chenyong; Zheng, Xiao; Xue, Fei; Du, Jiangfeng

2016-05-01

Nonlinearity in macroscopic mechanical systems may lead to abundant phenomena for fundamental studies and potential applications. However, it is difficult to generate nonlinearity due to the fact that macroscopic mechanical systems follow Hooke's law and respond linearly to external force, unless strong drive is used. Here we propose and experimentally realize high cubic nonlinear response in a macroscopic mechanical system by exploring the anharmonicity in chemical bonding interactions. We demonstrate the high tunability of nonlinear response by precisely controlling the chemical bonding interaction, and realize, at the single-bond limit, a cubic elastic constant of 1 × 1020 N m-3. This enables us to observe the resonator's vibrational bi-states transitions driven by the weak Brownian thermal noise at 6 K. This method can be flexibly applied to a variety of mechanical systems to improve nonlinear responses, and can be used, with further improvements, to explore macroscopic quantum mechanics.

Semen characteristics and selected biochemical markers of canine seminal plasma in various seasons of the year.

PubMed

Strzeżek, R; Szemplińska, K; Filipowicz, K; Kordan, W

2015-01-01

The aim of this study was to evaluate the influence of season on selected qualitative semen characteristics and biochemical markers of canine seminal plasma. Whole ejaculates were collected from 5 crossbred dogs aged 2-8 years. The study covered a period of one year divided into four seasons: spring (March, April, May), summer (June, July, August), autumn (September, October, November) and winter (December, January, February). Semen samples were subjected to macroscopic and microscopic analyses to determine semen volume, total sperm counts and sperm morphology parameters. The study also involved the determination of sperm motility parameters (CASA system), sperm plasma membrane integrity (SPMI, fluorescent staining SYBR-14/PI), sperm mitochondrial membrane potential (MMP, fluorescent staining JC-1/PI) and the ATP content of sperm cells. Total protein content (TPC) and the activity of alkaline phosphatase (AP) and acid phosphatase (AcP) were determined in biochemical analyses of seminal plasma. No significant differences in ejaculate volume, SMPI or ATP content of sperm cells were observed between seasons. The highest total sperm counts were reported in ejaculates acquired in summer and autumn. The lowest MMP values were determined in summer ejaculates. No significant differences in sperm motility (MOT) were observed throughout the experiment, but ejaculates collected in autumn and winter were characterized by the highest progressive motility (PMOT). AP activity and TPC were not significantly affected by season. However, AcP activity levels were significantly lower in autumn than in the remaining seasons. Seasonal variations in the analyzed macroscopic and microscopic parameters of ejaculates and biochemical markers of seminal plasma did not exert a clear negative effect on the quality of canine semen.

Synchronization invariance under network structural transformations

NASA Astrophysics Data System (ADS)

Arola-Fernández, Lluís; Díaz-Guilera, Albert; Arenas, Alex

2018-06-01

Synchronization processes are ubiquitous despite the many connectivity patterns that complex systems can show. Usually, the emergence of synchrony is a macroscopic observable; however, the microscopic details of the system, as, e.g., the underlying network of interactions, is many times partially or totally unknown. We already know that different interaction structures can give rise to a common functionality, understood as a common macroscopic observable. Building upon this fact, here we propose network transformations that keep the collective behavior of a large system of Kuramoto oscillators invariant. We derive a method based on information theory principles, that allows us to adjust the weights of the structural interactions to map random homogeneous in-degree networks into random heterogeneous networks and vice versa, keeping synchronization values invariant. The results of the proposed transformations reveal an interesting principle; heterogeneous networks can be mapped to homogeneous ones with local information, but the reverse process needs to exploit higher-order information. The formalism provides analytical insight to tackle real complex scenarios when dealing with uncertainty in the measurements of the underlying connectivity structure.

Structural Analysis of Enamel in Teeth from Head-and-Neck Cancer Patients Who Underwent Radiotherapy.

PubMed

Madrid, Cristhian C; de Pauli Paglioni, Mariana; Line, Sergio R; Vasconcelos, Karina G; Brandão, Thaís Bianca; Lopes, Marcio A; Santos-Silva, Alan Roger; De Goes, Mario Fernando

2017-01-01

To analyze macroscopic, microscopic, and ultrastructural aspects of enamel from head-and-neck cancer patients submitted to radiotherapy. Twenty sound extracted permanent molars were used and divided into 2 groups. The experimental group consisted of 10 molars from head-and-neck cancer patients submitted to radiotherapy with total doses that ranged from 50 to 70 Gy. Ten molars from patients who did not receive radiotherapy were matched with experimental-group samples by anatomic tooth group and comprised the control group. To perform a macroscopic analysis, standardized photos of different enamel faces were taken with a camera. Teeth were subjected to longitudinal cuts and hand polished to a final thickness of 0.1 mm. Enamel was analyzed under polarized light microscopy, and optical retardation values of birefringence were calculated in cervical, cusp, and occlusal pit areas. Subsequently, the same enamel areas were analyzed by scanning electron microscopy. Data from optical retardation values were statistically analyzed by 2-way ANOVA and Fisher's test (α < 0.05). No macroscopic differences were observed between the irradiated and control groups. Polarized light microscopy analysis revealed that cervical enamel exhibited darker areas characterized by discrete birefringence patterns compared to the control enamel. Optical retardation values were only significantly different in the cervical enamel of the irradiated and control groups (p < 0.0001). Scanning electron microscopy analysis revealed more evident interprismatic spaces in the cervical and outer cusp enamel of irradiated samples. Head-and-neck radiotherapy reduced optical retardation values of birefringence in cervical enamel, and the interprismatic spaces became more evident. © 2017 S. Karger AG, Basel.

Anti-inflammatory Efficiency of Ankaferd Blood Stopper in Experimental Distal Colitis Model

PubMed Central

Koçak, Erdem; Akbal, Erdem; Taş, Adnan; Köklü, Seyfettin; Karaca, Gökhan; Can, Murat; Kösem, Bahadır; Üstün, Hüseyin

2013-01-01

Background/Aim: Ankaferd blood stopper (ABS) is a herbal extract that enhances mucosal healing. In this study, we aimed to investigate the efficiency of ABS in the treatment of experimental distal colitis. Materials and Methods: Twenty one male albino rats were divided into three groups: Sham control (Group 1), colitis induced by acetic acid and treated with saline (Group 2), colitis induced by acetic acid and treated with ABS (Group 3). At end of the 7th day of induction, all the rats were lightly anesthetized with intramuscular ketamine (8 mg/kg) and thereafter laparotomy and total colectomy were performed. The distal colon segment was assessed macroscopically and microscopically. In addition malondialdehyde (MDA), superoxide dismutase (SOD) and nitric oxide (NO) levels of the colonic tissue and changes in body weight were measured. Results: The MDA and NO levels of the colonic tissues and weight loss were significantly higher in Group 2 compared to Group 1 and Group 3. Microscopic and macroscopic damage scores were significantly higher in Group 2 and Group 3 than Group 1 (P: 0.001, P: 0.004, respectively). Although the microscopic and macroscopic damage scores in Group 3 were slightly lower than Group 2, the difference was not statistically significant. The SOD levels of the colonic tissues were not different between the three groups. Conclusion: Weight alterations and high-levels of the colonic tissue MDA and NO suggested that ABS might have anti-inflammatory effects on experimental distal colitis. However, this suggestion was not supported by histopathological findings. PMID:23680710

Grasping the Second Law of Thermodynamics at University: The Consistency of Macroscopic and Microscopic Explanations

ERIC Educational Resources Information Center

Leinonen, Risto; Asikainen, Mervi A.; Hirvonen, Pekka E.

2015-01-01

This study concentrates on evaluating the consistency of upper-division students' use of the second law of thermodynamics at macroscopic and microscopic levels. Data were collected by means of a paper and pencil test (N = 48) focusing on the macroscopic and microscopic features of the second law concerned with heat transfer processes. The data…

Statistical foundations of liquid-crystal theory: II: Macroscopic balance laws.

PubMed

Seguin, Brian; Fried, Eliot

2013-01-01

Working on a state space determined by considering a discrete system of rigid rods, we use nonequilibrium statistical mechanics to derive macroscopic balance laws for liquid crystals. A probability function that satisfies the Liouville equation serves as the starting point for deriving each macroscopic balance. The terms appearing in the derived balances are interpreted as expected values and explicit formulas for these terms are obtained. Among the list of derived balances appear two, the tensor moment of inertia balance and the mesofluctuation balance, that are not standard in previously proposed macroscopic theories for liquid crystals but which have precedents in other theories for structured media.

Macroscopically Oriented Porous Materials with Periodic Ordered Structures: From Zeolites and Metal-Organic Frameworks to Liquid-Crystal-Templated Mesoporous Materials.

PubMed

Cho, Joonil; Ishida, Yasuhiro

2017-07-01

Porous materials with molecular-sized periodic structures, as exemplified by zeolites, metal-organic frameworks, or mesoporous silica, have attracted increasing attention due to their range of applications in storage, sensing, separation, and transformation of small molecules. Although the components of such porous materials have a tendency to pack in unidirectionally oriented periodic structures, such ideal types of packing cannot continue indefinitely, generally ceasing when they reach a micrometer scale. Consequently, most porous materials are composed of multiple randomly oriented domains, and overall behave as isotropic materials from a macroscopic viewpoint. However, if their channels could be unidirectionally oriented over a macroscopic scale, the resultant porous materials might serve as powerful tools for manipulating molecules. Guest molecules captured in macroscopically oriented channels would have their positions and directions well-defined, so that molecular events in the channels would proceed in a highly controlled manner. To realize such an ideal situation, numerous efforts have been made to develop various porous materials with macroscopically oriented channels. An overview of recent studies on the synthesis, properties, and applications of macroscopically oriented porous materials is presented. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Thermal Equilibrium of a Macroscopic Quantum System in a Pure State.

PubMed

Goldstein, Sheldon; Huse, David A; Lebowitz, Joel L; Tumulka, Roderich

2015-09-04

We consider the notion of thermal equilibrium for an individual closed macroscopic quantum system in a pure state, i.e., described by a wave function. The macroscopic properties in thermal equilibrium of such a system, determined by its wave function, must be the same as those obtained from thermodynamics, e.g., spatial uniformity of temperature and chemical potential. When this is true we say that the system is in macroscopic thermal equilibrium (MATE). Such a system may, however, not be in microscopic thermal equilibrium (MITE). The latter requires that the reduced density matrices of small subsystems be close to those obtained from the microcanonical, equivalently the canonical, ensemble for the whole system. The distinction between MITE and MATE is particularly relevant for systems with many-body localization for which the energy eigenfuctions fail to be in MITE while necessarily most of them, but not all, are in MATE. We note, however, that for generic macroscopic systems, including those with MBL, most wave functions in an energy shell are in both MATE and MITE. For a classical macroscopic system, MATE holds for most phase points on the energy surface, but MITE fails to hold for any phase point.

Multiscale Investigation on Biofilm Distribution and Its Impact on Macroscopic Biogeochemical Reaction Rates: BIOFILM DISTRIBUTION AND RATE SCALING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, Zhifeng; Liu, Chongxuan; Liu, Yuanyuan

Biofilms are critical locations for biogeochemical reactions in the subsurface environment. The occurrence and distribution of biofilms at microscale as well as their impacts on macroscopic biogeochemical reaction rates are still poorly understood. This paper investigated the formation and distributions of biofilms in heterogeneous sediments using multiscale models, and evaluated the effects of biofilm heterogeneity on local and macroscopic biogeochemical reaction rates. Sediment pore structures derived from X-ray computed tomography were used to simulate the microscale flow dynamics and biofilm distribution in the sediment column. The response of biofilm formation and distribution to the variations in hydraulic and chemical propertiesmore » was first examined. One representative biofilm distribution was then utilized to evaluate its effects on macroscopic reaction rates using nitrate reduction as an example. The results revealed that microorganisms primarily grew on the surfaces of grains and aggregates near preferential flow paths where both electron donor and acceptor were readily accessible, leading to the heterogeneous distribution of biofilms in the sediments. The heterogeneous biofilm distribution decreased the macroscopic rate of biogeochemical reactions as compared with those in homogeneous cases. Operationally considering the heterogeneous biofilm distribution in macroscopic reactive transport models such as using dual porosity domain concept can significantly improve the prediction of biogeochemical reaction rates. Overall, this study provided important insights into the biofilm formation and distribution in soils and sediments as well as their impacts on the macroscopic manifestation of reaction rates.« less

Multiscale Investigation on Biofilm Distribution and Its Impact on Macroscopic Biogeochemical Reaction Rates

NASA Astrophysics Data System (ADS)

Yan, Zhifeng; Liu, Chongxuan; Liu, Yuanyuan; Bailey, Vanessa L.

2017-11-01

Biofilms are critical locations for biogeochemical reactions in the subsurface environment. The occurrence and distribution of biofilms at microscale as well as their impacts on macroscopic biogeochemical reaction rates are still poorly understood. This paper investigated the formation and distributions of biofilms in heterogeneous sediments using multiscale models and evaluated the effects of biofilm heterogeneity on local and macroscopic biogeochemical reaction rates. Sediment pore structures derived from X-ray computed tomography were used to simulate the microscale flow dynamics and biofilm distribution in the sediment column. The response of biofilm formation and distribution to the variations in hydraulic and chemical properties was first examined. One representative biofilm distribution was then utilized to evaluate its effects on macroscopic reaction rates using nitrate reduction as an example. The results revealed that microorganisms primarily grew on the surfaces of grains and aggregates near preferential flow paths where both electron donor and acceptor were readily accessible, leading to the heterogeneous distribution of biofilms in the sediments. The heterogeneous biofilm distribution decreased the macroscopic rate of biogeochemical reactions as compared with those in homogeneous cases. Operationally considering the heterogeneous biofilm distribution in macroscopic reactive transport models such as using dual porosity domain concept can significantly improve the prediction of biogeochemical reaction rates. Overall, this study provided important insights into the biofilm formation and distribution in soils and sediments as well as their impacts on the macroscopic manifestation of reaction rates.

Photoeffect cross sections of some rare-earth elements at 145.4 keV

NASA Astrophysics Data System (ADS)

Umesh, T. K.; Ranganathaiah, C.; Sanjeevaiah, B.

1985-08-01

Total attenuation cross sections in the elements La, Ce, Pr, Nd, Sm, Gd, Dy, Ho, and Er were derived from the measured total cross sections of their simple oxide compounds, by employing the mixture rule at 145.4-keV photon energy. The compound cross sections have been measured by performing transmission experiments in a good geometry setup. From the derived total cross sections of elements, photoeffect cross sections have been obtained by subtracting the theoretical scattering cross sections. A good agreement is observed between the present data of photoeffect cross sections and Scofield's theoretical data.

Magneto-optic dynamics in a ferromagnetic nematic liquid crystal

NASA Astrophysics Data System (ADS)

Potisk, Tilen; Mertelj, Alenka; Sebastián, Nerea; Osterman, Natan; Lisjak, Darja; Brand, Helmut R.; Pleiner, Harald; Svenšek, Daniel

2018-01-01

We investigate dynamic magneto-optic effects in a ferromagnetic nematic liquid crystal experimentally and theoretically. Experimentally we measure the magnetization and the phase difference of the transmitted light when an external magnetic field is applied. As a model we study the coupled dynamics of the magnetization, M , and the director field, n , associated with the liquid crystalline orientational order. We demonstrate that the experimentally studied macroscopic dynamic behavior reveals the importance of a dynamic cross-coupling between M and n . The experimental data are used to extract the value of the dissipative cross-coupling coefficient. We also make concrete predictions about how reversible cross-coupling terms between the magnetization and the director could be detected experimentally by measurements of the transmitted light intensity as well as by analyzing the azimuthal angle of the magnetization and the director out of the plane spanned by the anchoring axis and the external magnetic field. We derive the eigenmodes of the coupled system and study their relaxation rates. We show that in the usual experimental setup used for measuring the relaxation rates of the splay-bend or twist-bend eigenmodes of a nematic liquid crystal one expects for a ferromagnetic nematic liquid crystal a mixture of at least two eigenmodes.

Search for ternary fission of chromium-48

NASA Astrophysics Data System (ADS)

Dummer, Andrew K.

1999-07-01

Both alpha cluster model calculations and macroscopic energy calculations that allow for a double-neck shape of the compound nucleus suggest the possibility of a novel three 16O, chain-like configuration in 48 Cr. Such a configuration might lead to an enhanced cross section for three-16O breakup. To explore this possibility, the three-body exit channels for the 36Ar + 12C reaction at a beam energy of 210 MeV have been studied. The cross section for 16O + 16O + 16O breakup has been deduced and has been found to be in excess of what would be expected to result from a sequential binary fission process. However, the observation of a similarly enhanced 12C + 16O + 20Ne breakup cross section suggests that the observed 16O + 16O + 16O yields might still be associated with a statistical fission process. The results are discussed in the context of the fission of light nuclear systems and a simple cluster model calculation. This latter, ``Harvey model'' calculation suggests a possible inhibition of the formation of a three- 16O chain configuration from the 36Ar + 12C entrance channel. A further measurement using the 20Ne + 28Si-entrance channel is suggested.

Conformal bootstrap at large charge

NASA Astrophysics Data System (ADS)

Jafferis, Daniel; Mukhametzhanov, Baur; Zhiboedov, Alexander

2018-05-01

We consider unitary CFTs with continuous global symmetries in d > 2. We consider a state created by the lightest operator of large charge Q ≫ 1 and analyze the correlator of two light charged operators in this state. We assume that the correlator admits a well-defined large Q expansion and, relatedly, that the macroscopic (thermodynamic) limit of the correlator exists. We find that the crossing equations admit a consistent truncation, where only a finite number N of Regge trajectories contribute to the correlator at leading nontrivial order. We classify all such truncated solutions to the crossing. For one Regge trajectory N = 1, the solution is unique and given by the effective field theory of a Goldstone mode. For two or more Regge trajectories N ≥ 2, the solutions are encoded in roots of a certain degree N polynomial. Some of the solutions admit a simple weakly coupled EFT description, whereas others do not. In the weakly coupled case, each Regge trajectory corresponds to a field in the effective Lagrangian.

Nonlinear effects in time-dependent transonic flows: An analysis of analog black hole stability

NASA Astrophysics Data System (ADS)

Michel, Florent; Parentani, Renaud

2015-05-01

We study solutions of the one-dimensional Gross-Pitaevskii equation to better understand dynamical instabilities occurring in flowing atomic condensates. Whereas transonic stationary flows can be fully described in simple terms, time-dependent flows exhibit a wide variety of behaviors. When the sound speed is crossed once, we observe that flows analogous to black holes obey something similar to the so-called no hair theorem since their late time profile is stationary and uniquely fixed by parameters entering the Hamiltonian and conserved quantities. For flows analogous to white holes, at late time one finds a macroscopic undulation in the supersonic side which has either a fixed amplitude or a widely varying one, signaling a quasiperiodic emission of solitons on the subsonic side. When considering flows which cross the sound speed twice, we observe various scenarios which can be understood from the above behaviors and from the hierarchy of the growth rates of the dynamical instabilities characterizing such flows.

Optical second harmonic generation from Pt nanowires with boomerang-like cross-sectional shapes

NASA Astrophysics Data System (ADS)

Ogata, Yoichi; Anh Tuan, Nguyen; Miyauchi, Yoshihiro; Mizutani, Goro

2011-08-01

We have fabricated Pt nanowires with boomerang-like cross-sectional shapes on the MgO(110) faceted template and observed their optical second-harmonic generation (SHG) response. In the TEM images the Pt nanowires on the MgO substrate had macroscopic C2v symmetry, however, their structure had microscopic imperfections. In the SHG response, as a function of the sample rotation angle around the substrate normal, we found contributions from the nonlinear susceptibility elements χ113, χ223, χ311, χ322, and χ333 originating from the broken symmetry in the 3; [110] direction of the MgO substrate. The indices 1 and 2 denote the [001] and [11¯0] directions, respectively. Under C2v symmetry no SHG is expected in the s-in/s-out polarization configuration, however, a finite SHG was observed in this polarization configuration. We suggest that the SHG in the forbidden configuration might originate from the imperfections in the nanowire structure.

Crossing Over from Attractive to Repulsive Interactions in a Tunneling Bosonic Josephson Junction.

PubMed

Spagnolli, G; Semeghini, G; Masi, L; Ferioli, G; Trenkwalder, A; Coop, S; Landini, M; Pezzè, L; Modugno, G; Inguscio, M; Smerzi, A; Fattori, M

2017-06-09

We explore the interplay between tunneling and interatomic interactions in the dynamics of a bosonic Josephson junction. We tune the scattering length of an atomic ^{39}K Bose-Einstein condensate confined in a double-well trap to investigate regimes inaccessible to other superconducting or superfluid systems. In the limit of small-amplitude oscillations, we study the transition from Rabi to plasma oscillations by crossing over from attractive to repulsive interatomic interactions. We observe a critical slowing down in the oscillation frequency by increasing the strength of an attractive interaction up to the point of a quantum phase transition. With sufficiently large initial oscillation amplitude and repulsive interactions, the system enters the macroscopic quantum self-trapping regime, where we observe coherent undamped oscillations with a self-sustained average imbalance of the relative well population. The exquisite agreement between theory and experiments enables the observation of a broad range of many body coherent dynamical regimes driven by tunable tunneling energy, interactions and external forces, with applications spanning from atomtronics to quantum metrology.

Quantum Bell inequalities from macroscopic locality

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Tzyh Haur; Sheridan, Lana; Navascues, Miguel

2011-02-15

We propose a method to generate analytical quantum Bell inequalities based on the principle of macroscopic locality. By imposing locality over binary processings of virtual macroscopic intensities, we establish a correspondence between Bell inequalities and quantum Bell inequalities in bipartite scenarios with dichotomic observables. We discuss how to improve the latter approximation and how to extend our ideas to scenarios with more than two outcomes per setting.

Renal Sinus Fat Invasion and Tumoral Thrombosis of the Inferior Vena Cava-Renal Vein: Only Confined to Renal Cell Carcinoma

PubMed Central

Harman, Mustafa; Guneyli, Serkan; Sen, Sait; Elmas, Nevra

2014-01-01

Epithelioid angiomyolipoma (E-AML), accounting for 8% of renal angiomyolipoma, is usually associated with tuberous sclerosis (TS) and demonstrates aggressive behavior. E-AML is macroscopically seen as a large infiltrative necrotic tumor with occasional extension into renal vein and/or inferior vena cava. However, without history of TS, renal sinus and venous invasion E-AML would be a challenging diagnosis, which may lead radiologists to misinterpret it as a renal cell carcinoma (RCC). In this case presentation, we aimed to report cross-sectional imaging findings of two cases diagnosed as E-AML and pathological correlation of these aforementioned masses mimicking RCC. PMID:25506021

Renal sinus fat invasion and tumoral thrombosis of the inferior vena cava-renal vein: only confined to renal cell carcinoma.

PubMed

Acar, Turker; Harman, Mustafa; Guneyli, Serkan; Sen, Sait; Elmas, Nevra

2014-01-01

Epithelioid angiomyolipoma (E-AML), accounting for 8% of renal angiomyolipoma, is usually associated with tuberous sclerosis (TS) and demonstrates aggressive behavior. E-AML is macroscopically seen as a large infiltrative necrotic tumor with occasional extension into renal vein and/or inferior vena cava. However, without history of TS, renal sinus and venous invasion E-AML would be a challenging diagnosis, which may lead radiologists to misinterpret it as a renal cell carcinoma (RCC). In this case presentation, we aimed to report cross-sectional imaging findings of two cases diagnosed as E-AML and pathological correlation of these aforementioned masses mimicking RCC.

Multi-resolution waveguide image slicer for the PEPSI instrument

NASA Astrophysics Data System (ADS)

Beckert, Erik; Strassmeier, Klaus G.; Woche, Manfred; Harnisch, Gerd; Hornaff, Marcel; Weber, Michael; Barnes, Stuart

2016-07-01

A waveguide image slicer with resolutions up to 270.000 (planned: 300.000) for the fiber fed PEPSI echelle spectrograph at the LBT and single waveguide thicknesses of down to 70 μm has been manufactured and tested. The waveguides were macroscopically prepared, stacked up to an order of seven and thinned back to square stack cross sections. A high filling ratio was achieved by realizing homogenous adhesive gaps of 3.6 μm, using index matching adhesives for TIR within the waveguides. The image slicer stacks are used in immersion mode and are miniaturized to enable implementation in a set of 2x8. The overall efficiency is between 92 % and 96 %.

3D-Microarchitectural patterns of Hyperostosis frontalis interna: a micro-computed tomography study in aged women.

PubMed

Bracanovic, Djurdja; Djonic, Danijela; Nikolic, Slobodan; Milovanovic, Petar; Rakocevic, Zoran; Zivkovic, Vladimir; Djuric, Marija

2016-11-01

Although seen frequently during dissections and autopsies, Hyperostosis frontalis interna (HFI) - a morphological pattern of the frontal bone thickening - is often ignored and its nature and development are not yet understood sufficiently. Current macroscopic classification defines four grades/stages of HFI based on the morphological appearance and size of the affected area; however, it is unclear if these stages also depict the successive phases in the HFI development. Here we assessed 3D-microarchitecture of the frontal bone in women with various degrees of HFI expression and in an age- and sex-matched control group, hypothesizing that the bone microarchitecture bears imprints of the pathogenesis of HFI and may clarify the phases of its development. Frontal bone samples were collected during routine autopsies from 20 women with HFI (age: 69.9 ± 11.1 years) and 14 women without HFI (age: 74.1 ± 9.7 years). We classified the HFI samples into four groups, each group demonstrating different macroscopic type or stage of HFI. All samples were scanned by micro-computed tomography to evaluate 3D bone microarchitecture in the following regions of interest: total sample, outer table, diploe and inner table. Our results revealed that, compared to the control group, the women with HFI showed a significantly increased bone volume fraction in the region of diploe, along with significantly thicker and more plate-like shaped trabeculae and reduced trabecular separation and connectivity density. Moreover, the inner table of the frontal bone in women with HFI displayed significantly increased total porosity and mean pore diameter compared to controls. Microstructural reorganization of the frontal bone in women with HFI was also reflected in significantly higher porosity and lower bone volume fraction in the inner vs. outer table due to an increased number of pores larger than 100 μm. The individual comparisons between the control group and different macroscopic stages of HFI revealed significant differences only between the control group and the morphologically most pronounced type of HFI. Our microarchitectural findings demonstrated clear differences between the HFI and the control group in the region of diploe and the inner table. Macroscopic grades of HFI could not be distinguished at the level of bone microarchitecture and their consecutive nature cannot be supported. Rather, our study suggests that only two different types of HFI (moderate and severe HFI) have microstructural justification and should be considered further. It is essential to record HFI systematically in human postmortem subjects to provide more data on the mechanisms of its development. © 2016 Anatomical Society.

Electric-field-induced strain contributions in morphotropic phase boundary composition of (Bi{sub 1/2}Na{sub 1/2})TiO{sub 3}-BaTiO{sub 3} during poling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khansur, Neamul H.; Daniels, John E.; Hinterstein, Manuel

2015-12-14

The microscopic contributions to the electric-field-induced macroscopic strain in a morphotropic 0.93(Bi{sub 1/2}Na{sub 1/2}TiO{sub 3})−0.07(BaTiO{sub 3}) with a mixed rhombohedral and tetragonal structure have been quantified using full pattern Rietveld refinement of in situ high-energy x-ray diffraction data. The analysis methodology allows a quantification of all strain mechanisms for each phase in a morphotropic composition and is applicable to use in a wide variety of piezoelectric compositions. It is shown that during the poling of this material 24%, 44%, and 32% of the total macroscopic strain is generated from lattice strain, domain switching, and phase transformation strains, respectively. The resultsmore » also suggest that the tetragonal phase contributes the most to extrinsic domain switching strain, whereas the lattice strain primarily stems from the rhombohedral phase. The analysis also suggests that almost 32% of the total strain is lost or is a one-time effect due to the irreversible nature of the electric-field-induced phase transformation in the current composition. This information is relevant to on-going compositional development strategies to harness the electric-field-induced phase transformation strain of (Bi{sub 1/2}Na{sub 1/2})TiO{sub 3}-based lead-free piezoelectric materials for actuator applications.« less

Manganese dioxide decoration of macroscopic carbon nanotube fibers: From high-performance liquid-based to all-solid-state supercapacitors

NASA Astrophysics Data System (ADS)

Pendashteh, Afshin; Senokos, Evgeny; Palma, Jesus; Anderson, Marc; Vilatela, Juan J.; Marcilla, Rebeca

2017-12-01

Supercapacitors capable of providing high voltage, energy and power density but yet light, low volume occupying, flexible and mechanically robust are highly interesting and demanded for portable applications. Herein, freestanding flexible hybrid electrodes based on MnO2 nanoparticles grown on macroscopic carbon nanotube fibers (CNTf-MnO2) were fabricated, without the need of any metallic current collector. The CNTf, a support with excellent electrical conductivity, mechanical stability, and appropriate pore structure, was homogeneously decorated with porous akhtenskite ɛ-MnO2 nanoparticles produced via electrodeposition in an optimized organic-aqueous mixture. Electrochemical properties of these decorated fibers were evaluated in different electrolytes including a neutral aqueous solution and a pure 1-butyl-3-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ionic liquid (PYR14TFSI). This comparison helps discriminate the various contributions to the total capacitance: (surface) Faradaic and non-Faradaic processes, improved wetting by aqueous electrolytes. Accordingly, symmetric supercapacitors with PYR14TFSI led to a high specific energy of 36 Wh· kgMnO2-1 (16 Wh·kg-1 including the weight of CNTf) and real specific power of 17 kW· kgMnO2-1 (7.5 kW kg-1) at 3.0 V with excellent cycling stability. Moreover, flexible all solid-state supercapacitors were fabricated using PYR14TFSI-based polymer electrolyte, exhibiting maximum energy density of 21 Wh·kg-1 and maximum power density of 8 kW kg-1 normalized by total active material.

Energy and Mass-Number Dependence of Hadron-Nucleus Total Reaction Cross Sections

NASA Astrophysics Data System (ADS)

Kohama, Akihisa; Iida, Kei; Oyamatsu, Kazuhiro

2016-09-01

We thoroughly investigate how proton-nucleus total reaction cross sections depend on the target mass number A and the proton incident energy. In doing so, we systematically analyze nuclear reaction data that are sensitive to nuclear size, namely, proton-nucleus total reaction cross sections and differential elastic cross sections, using a phenomenological black-sphere approximation of nuclei that we are developing. In this framework, the radius of the black sphere is found to be a useful length scale that simultaneously accounts for the observed proton-nucleus total reaction cross section and first diffraction peak in the proton elastic differential cross section. This framework, which is shown here to be applicable to antiprotons, is expected to be applicable to any kind of projectile that is strongly attenuated in the nucleus. On the basis of a cross-section formula constructed within this framework, we find that a less familiar A1/6 dependence plays a crucial role in describing the energy dependence of proton-nucleus total reaction cross sections.

Process Analytical Technology for Advanced Process Control in Biologics Manufacturing with the Aid of Macroscopic Kinetic Modeling.

PubMed

Kornecki, Martin; Strube, Jochen

2018-03-16

Productivity improvements of mammalian cell culture in the production of recombinant proteins have been made by optimizing cell lines, media, and process operation. This led to enhanced titers and process robustness without increasing the cost of the upstream processing (USP); however, a downstream bottleneck remains. In terms of process control improvement, the process analytical technology (PAT) initiative, initiated by the American Food and Drug Administration (FDA), aims to measure, analyze, monitor, and ultimately control all important attributes of a bioprocess. Especially, spectroscopic methods such as Raman or near-infrared spectroscopy enable one to meet these analytical requirements, preferably in-situ. In combination with chemometric techniques like partial least square (PLS) or principal component analysis (PCA), it is possible to generate soft sensors, which estimate process variables based on process and measurement models for the enhanced control of bioprocesses. Macroscopic kinetic models can be used to simulate cell metabolism. These models are able to enhance the process understanding by predicting the dynamic of cells during cultivation. In this article, in-situ turbidity (transmission, 880 nm) and ex-situ Raman spectroscopy (785 nm) measurements are combined with an offline macroscopic Monod kinetic model in order to predict substrate concentrations. Experimental data of Chinese hamster ovary cultivations in bioreactors show a sufficiently linear correlation (R² ≥ 0.97) between turbidity and total cell concentration. PLS regression of Raman spectra generates a prediction model, which was validated via offline viable cell concentration measurement (RMSE ≤ 13.82, R² ≥ 0.92). Based on these measurements, the macroscopic Monod model can be used to determine different process attributes, e.g., glucose concentration. In consequence, it is possible to approximately calculate (R² ≥ 0.96) glucose concentration based on online cell concentration measurements using turbidity or Raman spectroscopy. Future approaches will use these online substrate concentration measurements with turbidity and Raman measurements, in combination with the kinetic model, in order to control the bioprocess in terms of feeding strategies, by employing an open platform communication (OPC) network-either in fed-batch or perfusion mode, integrated into a continuous operation of upstream and downstream.

Process Analytical Technology for Advanced Process Control in Biologics Manufacturing with the Aid of Macroscopic Kinetic Modeling

PubMed Central

Kornecki, Martin; Strube, Jochen

2018-01-01

Productivity improvements of mammalian cell culture in the production of recombinant proteins have been made by optimizing cell lines, media, and process operation. This led to enhanced titers and process robustness without increasing the cost of the upstream processing (USP); however, a downstream bottleneck remains. In terms of process control improvement, the process analytical technology (PAT) initiative, initiated by the American Food and Drug Administration (FDA), aims to measure, analyze, monitor, and ultimately control all important attributes of a bioprocess. Especially, spectroscopic methods such as Raman or near-infrared spectroscopy enable one to meet these analytical requirements, preferably in-situ. In combination with chemometric techniques like partial least square (PLS) or principal component analysis (PCA), it is possible to generate soft sensors, which estimate process variables based on process and measurement models for the enhanced control of bioprocesses. Macroscopic kinetic models can be used to simulate cell metabolism. These models are able to enhance the process understanding by predicting the dynamic of cells during cultivation. In this article, in-situ turbidity (transmission, 880 nm) and ex-situ Raman spectroscopy (785 nm) measurements are combined with an offline macroscopic Monod kinetic model in order to predict substrate concentrations. Experimental data of Chinese hamster ovary cultivations in bioreactors show a sufficiently linear correlation (R2 ≥ 0.97) between turbidity and total cell concentration. PLS regression of Raman spectra generates a prediction model, which was validated via offline viable cell concentration measurement (RMSE ≤ 13.82, R2 ≥ 0.92). Based on these measurements, the macroscopic Monod model can be used to determine different process attributes, e.g., glucose concentration. In consequence, it is possible to approximately calculate (R2 ≥ 0.96) glucose concentration based on online cell concentration measurements using turbidity or Raman spectroscopy. Future approaches will use these online substrate concentration measurements with turbidity and Raman measurements, in combination with the kinetic model, in order to control the bioprocess in terms of feeding strategies, by employing an open platform communication (OPC) network—either in fed-batch or perfusion mode, integrated into a continuous operation of upstream and downstream. PMID:29547557

Amplification of intrinsic fluctuations by the Lorenz equations

NASA Astrophysics Data System (ADS)

Fox, Ronald F.; Elston, T. C.

1993-07-01

Macroscopic systems (e.g., hydrodynamics, chemical reactions, electrical circuits, etc.) manifest intrinsic fluctuations of molecular and thermal origin. When the macroscopic dynamics is deterministically chaotic, the intrinsic fluctuations may become amplified by several orders of magnitude. Numerical studies of this phenomenon are presented in detail for the Lorenz model. Amplification to macroscopic scales is exhibited, and quantitative methods (binning and a difference-norm) are presented for measuring macroscopically subliminal amplification effects. In order to test the quality of the numerical results, noise induced chaos is studied around a deterministically nonchaotic state, where the scaling law relating the Lyapunov exponent to noise strength obtained for maps is confirmed for the Lorenz model, a system of ordinary differential equations.

The Segmental Morphometric Properties of the Horse Cervical Spinal Cord: A Study of Cadaver

PubMed Central

Bahar, Sadullah; Bolat, Durmus; Selcuk, Muhammet Lutfi

2013-01-01

Although the cervical spinal cord (CSC) of the horse has particular importance in diseases of CNS, there is very little information about its segmental morphometry. The objective of the present study was to determine the morphometric features of the CSC segments in the horse and possible relationships among the morphometric features. The segmented CSC from five mature animals was used. Length, weight, diameter, and volume measurements of the segments were performed macroscopically. Lengths and diameters of segments were measured histologically, and area and volume measurements were performed using stereological methods. The length, weight, and volume of the CSC were 61.6 ± 3.2 cm, 107.2 ± 10.4 g, and 95.5 ± 8.3 cm3, respectively. The length of the segments was increased from C 1 to C 3, while it decreased from C 3 to C 8. The gross section (GS), white matter (WM), grey matter (GM), dorsal horn (DH), and ventral horn (VH) had the largest cross-section areas at C 8. The highest volume was found for the total segment and WM at C 4, GM, DH, and VH at C 7, and the central canal (CC) at C 3. The data obtained not only contribute to the knowledge of the normal anatomy of the CSC but may also provide reference data for veterinary pathologists and clinicians. PMID:23476145

[Different aspects of magnetic resonance imaging of muscles between dermatomyositis and polymyositis].

PubMed

Miranda, Sofia Silveira de Castro; Alvarenga, Daniel; Rodrigues, João Carlos; Shinjo, Samuel Katsuyuki

2014-01-01

Although dermatomyositis (DM) and polymyositis (PM) share many clinical features in common, they have distinct pathophysiological and histological features. It is possible that these distinctions reflect also macroscopically, for example, in muscle alterations seen in magnetic resonance images (MRI). To compare simultaneously the MRI of various muscle compartments of the thighs of adult DM and PM. The present study is a cross-sectional that included, between 2010 and 2013, 11 newly diagnosed DM and 11 PM patients (Bohan and Peter's criteria, 1975), with clinical and laboratory activity. They were valued at RM thighs, T1 and T2 with fat suppression, 1.5 T MRI scanner sequences. The mean age at the time of MRI, the time between onset of symptoms and the realization of the MRI distribution of sex and drug therapy were comparable between the two groups (p>0.050). Concerning the MRI, muscle edema was significantly found in DM, and mainly in the proximal region of the muscles. The area of fat replacement was found predominantly in PM. The partial fat replacement area occurred mainly in the medial and distal region, whereas the total fat replacement area occurred mainly in the distal muscles. There was no area of muscle fibrosis. DM and PM have different characteristics on MRI muscles, alike pathophysiological and histological distinctions. Copyright © 2014 Elsevier Editora Ltda. All rights reserved.

Comparison of prevalence estimation of Mycobacterium avium subsp. paratuberculosis infection by sampling slaughtered cattle with macroscopic lesions vs. systematic sampling.

PubMed

Elze, J; Liebler-Tenorio, E; Ziller, M; Köhler, H

2013-07-01

The objective of this study was to identify the most reliable approach for prevalence estimation of Mycobacterium avium ssp. paratuberculosis (MAP) infection in clinically healthy slaughtered cattle. Sampling of macroscopically suspect tissue was compared to systematic sampling. Specimens of ileum, jejunum, mesenteric and caecal lymph nodes were examined for MAP infection using bacterial microscopy, culture, histopathology and immunohistochemistry. MAP was found most frequently in caecal lymph nodes, but sampling more tissues optimized the detection rate. Examination by culture was most efficient while combination with histopathology increased the detection rate slightly. MAP was detected in 49/50 animals with macroscopic lesions representing 1.35% of the slaughtered cattle examined. Of 150 systematically sampled macroscopically non-suspect cows, 28.7% were infected with MAP. This indicates that the majority of MAP-positive cattle are slaughtered without evidence of macroscopic lesions and before clinical signs occur. For reliable prevalence estimation of MAP infection in slaughtered cattle, systematic random sampling is essential.

X-ray-generated heralded macroscopical quantum entanglement of two nuclear ensembles.

PubMed

Liao, Wen-Te; Keitel, Christoph H; Pálffy, Adriana

2016-09-19

Heralded entanglement between macroscopical samples is an important resource for present quantum technology protocols, allowing quantum communication over large distances. In such protocols, optical photons are typically used as information and entanglement carriers between macroscopic quantum memories placed in remote locations. Here we investigate theoretically a new implementation which employs more robust x-ray quanta to generate heralded entanglement between two crystal-hosted macroscopical nuclear ensembles. Mössbauer nuclei in the two crystals interact collectively with an x-ray spontaneous parametric down conversion photon that generates heralded macroscopical entanglement with coherence times of approximately 100 ns at room temperature. The quantum phase between the entangled crystals can be conveniently manipulated by magnetic field rotations at the samples. The inherent long nuclear coherence times allow also for mechanical manipulations of the samples, for instance to check the stability of entanglement in the x-ray setup. Our results pave the way for first quantum communication protocols that use x-ray qubits.

Generating giant and tunable nonlinearity in a macroscopic mechanical resonator from a single chemical bond.

PubMed

Huang, Pu; Zhou, Jingwei; Zhang, Liang; Hou, Dong; Lin, Shaochun; Deng, Wen; Meng, Chao; Duan, Changkui; Ju, Chenyong; Zheng, Xiao; Xue, Fei; Du, Jiangfeng

2016-05-26

Nonlinearity in macroscopic mechanical systems may lead to abundant phenomena for fundamental studies and potential applications. However, it is difficult to generate nonlinearity due to the fact that macroscopic mechanical systems follow Hooke's law and respond linearly to external force, unless strong drive is used. Here we propose and experimentally realize high cubic nonlinear response in a macroscopic mechanical system by exploring the anharmonicity in chemical bonding interactions. We demonstrate the high tunability of nonlinear response by precisely controlling the chemical bonding interaction, and realize, at the single-bond limit, a cubic elastic constant of 1 × 10(20) N m(-3). This enables us to observe the resonator's vibrational bi-states transitions driven by the weak Brownian thermal noise at 6 K. This method can be flexibly applied to a variety of mechanical systems to improve nonlinear responses, and can be used, with further improvements, to explore macroscopic quantum mechanics.

Generating giant and tunable nonlinearity in a macroscopic mechanical resonator from a single chemical bond

PubMed Central

Huang, Pu; Zhou, Jingwei; Zhang, Liang; Hou, Dong; Lin, Shaochun; Deng, Wen; Meng, Chao; Duan, Changkui; Ju, Chenyong; Zheng, Xiao; Xue, Fei; Du, Jiangfeng

2016-01-01

Nonlinearity in macroscopic mechanical systems may lead to abundant phenomena for fundamental studies and potential applications. However, it is difficult to generate nonlinearity due to the fact that macroscopic mechanical systems follow Hooke's law and respond linearly to external force, unless strong drive is used. Here we propose and experimentally realize high cubic nonlinear response in a macroscopic mechanical system by exploring the anharmonicity in chemical bonding interactions. We demonstrate the high tunability of nonlinear response by precisely controlling the chemical bonding interaction, and realize, at the single-bond limit, a cubic elastic constant of 1 × 1020 N m−3. This enables us to observe the resonator's vibrational bi-states transitions driven by the weak Brownian thermal noise at 6 K. This method can be flexibly applied to a variety of mechanical systems to improve nonlinear responses, and can be used, with further improvements, to explore macroscopic quantum mechanics. PMID:27225287

Validation of In utero Tractography of Human Fetal Commissural and Internal Capsule Fibers with Histological Structure Tensor Analysis

PubMed Central

Mitter, Christian; Jakab, András; Brugger, Peter C.; Ricken, Gerda; Gruber, Gerlinde M.; Bettelheim, Dieter; Scharrer, Anke; Langs, Georg; Hainfellner, Johannes A.; Prayer, Daniela; Kasprian, Gregor

2015-01-01

Diffusion tensor imaging (DTI) and tractography offer the unique possibility to visualize the developing white matter macroanatomy of the human fetal brain in vivo and in utero and are currently under investigation for their potential use in the diagnosis of developmental pathologies of the human central nervous system. However, in order to establish in utero DTI as a clinical imaging tool, an independent comparison between macroscopic imaging and microscopic histology data in the same subject is needed. The present study aimed to cross-validate normal as well as abnormal in utero tractography results of commissural and internal capsule fibers in human fetal brains using postmortem histological structure tensor (ST) analysis. In utero tractography findings from two structurally unremarkable and five abnormal fetal brains were compared to the results of postmortem ST analysis applied to digitalized whole hemisphere sections of the same subjects. An approach to perform ST-based deterministic tractography in histological sections was implemented to overcome limitations in correlating in utero tractography to postmortem histology data. ST analysis and histology-based tractography of fetal brain sections enabled the direct assessment of the anisotropic organization and main fiber orientation of fetal telencephalic layers on a micro- and macroscopic scale, and validated in utero tractography results of corpus callosum and internal capsule fiber tracts. Cross-validation of abnormal in utero tractography results could be achieved in four subjects with agenesis of the corpus callosum (ACC) and in two cases with malformations of internal capsule fibers. In addition, potential limitations of current DTI-based in utero tractography could be demonstrated in several brain regions. Combining the three-dimensional nature of DTI-based in utero tractography with the microscopic resolution provided by histological ST analysis may ultimately facilitate a more complete morphologic characterization of axon guidance disorders at prenatal stages of human brain development. PMID:26732460

Are Cloned Quantum States Macroscopic?

NASA Astrophysics Data System (ADS)

Fröwis, F.; Dür, W.

2012-10-01

We study quantum states produced by optimal phase covariant quantum cloners. We argue that cloned quantum superpositions are not macroscopic superpositions in the spirit of Schrödinger’s cat, despite their large particle number. This is indicated by calculating several measures for macroscopic superpositions from the literature, as well as by investigating the distinguishability of the two superposed cloned states. The latter rapidly diminishes when considering imperfect detectors or noisy states and does not increase with the system size. In contrast, we find that cloned quantum states themselves are macroscopic, in the sense of both proposed measures and their usefulness in quantum metrology with an optimal scaling in system size. We investigate the applicability of cloned states for parameter estimation in the presence of different kinds of noise.

Universal ideal behavior and macroscopic work relation of linear irreversible stochastic thermodynamics

NASA Astrophysics Data System (ADS)

Ma, Yi-An; Qian, Hong

2015-06-01

We revisit the Ornstein-Uhlenbeck (OU) process as the fundamental mathematical description of linear irreversible phenomena, with fluctuations, near an equilibrium. By identifying the underlying circulating dynamics in a stationary process as the natural generalization of classical conservative mechanics, a bridge between a family of OU processes with equilibrium fluctuations and thermodynamics is established through the celebrated Helmholtz theorem. The Helmholtz theorem provides an emergent macroscopic ‘equation of state’ of the entire system, which exhibits a universal ideal thermodynamic behavior. Fluctuating macroscopic quantities are studied from the stochastic thermodynamic point of view and a non-equilibrium work relation is obtained in the macroscopic picture, which may facilitate experimental study and application of the equalities due to Jarzynski, Crooks, and Hatano and Sasa.

Ground testing of bioconvective variables such as morphological characterizations and mechanisms which regulate macroscopic patterns

NASA Technical Reports Server (NTRS)

Johnson, Adriel D.

1992-01-01

Conditions simulating low- and high-gravity, reveal changes in macroscopic pattern formation in selected microorganisms, but whether these structures are gravity dependent is not clear. Two theories have been identified in the fluid dynamics community which support macroscopic pattern formation. The first one is gravity dependent (fluid density models) where small concentrated regions of organisms sink unstably, and the second is gravity independent (wave reinforcement theory) where organisms align their movements in concert, such that either their swimming strokes beat in phase or their vortices entrain neighbors to follow parallel paths. Studies have shown that macroscopic pattern formation is consistent with the fluid density models for protozoa and algae and wave reinforcement hypothesis for caprine spermatozoa.

Fission fragment mass and total kinetic energy distributions of spontaneously fissioning plutonium isotopes

NASA Astrophysics Data System (ADS)

Pomorski, K.; Nerlo-Pomorska, B.; Bartel, J.; Schmitt, C.

2018-03-01

The fission-fragment mass and total kinetic energy (TKE) distributions are evaluated in a quantum mechanical framework using elongation, mass asymmetry, neck degree of freedom as the relevant collective parameters in the Fourier shape parametrization recently developed by us. The potential energy surfaces (PES) are calculated within the macroscopic-microscopic model based on the Lublin-Strasbourg Drop (LSD), the Yukawa-folded (YF) single-particle potential and a monopole pairing force. The PES are presented and analysed in detail for even-even Plutonium isotopes with A = 236-246. They reveal deep asymmetric valleys. The fission-fragment mass and TKE distributions are obtained from the ground state of a collective Hamiltonian computed within the Born-Oppenheimer approximation, in the WKB approach by introducing a neck-dependent fission probability. The calculated mass and total kinetic energy distributions are found in good agreement with the data.

Thrombotic Depositions on Right Impeller of Double-Ended Centrifugal Total Artificial Heart In Vivo.

PubMed

Karimov, Jamshid H; Horvath, David J; Okano, Shinji; Goodin, Mark; Sunagawa, Gengo; Byram, Nicole; Moazami, Nader; Golding, Leonard A R; Fukamachi, Kiyotaka

2017-05-01

The development of total artificial heart devices is a complex undertaking that includes chronic biocompatibility assessment of the device. It is considered particularly important to assess whether device design and features can be compatible long term in a biological environment. As part of the development program for the Cleveland Clinic continuous-flow total artificial heart (CFTAH), we evaluated the device for signs of thrombosis and biological material deposition in four animals that had achieved the intended 14-, 30-, or 90-day durations in each respective experiment. Explanted CFTAHs were analyzed for possible clot buildup at "susceptible" areas inside the pump, particularly the right pump impeller. Depositions of various consistency and shapes were observed. We here report our findings, along with macroscopic and microscopic analysis post explant, and provide computational fluid dynamics data with its potential implications for thrombus formation. © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Neutron lifetimes behavior analysis considering the two-region kinetic model in the IPEN/MB-01 reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gonnelli, Eduardo; Diniz, Ricardo

2014-11-11

This is a complementary work about the behavior analysis of the neutron lifetimes that was developed in the IPEN/MB-01 nuclear reactor facility. The macroscopic neutron noise technique was experimentally employed using pulse mode detectors for two stages of control rods insertion, where a total of twenty levels of subcriticality have been carried out. It was also considered that the neutron reflector density was treated as an additional group of delayed neutrons, being a sophisticated approach in the two-region kinetic theoretical model.

Symmetric and asymmetric exchange stiffnesses of transition-metal thin film interfaces in external electric field

NASA Astrophysics Data System (ADS)

Nakamura, K.; Pradipto, A.-M.; Akiyama, T.; Ito, T.; Oguchi, T.; Weinert, M.

2018-07-01

The electric-field induced modifications of the symmetric and asymmetric exchange stiffness constants for the prototypical transition-metal system of a Co monolayer on Pt(111) are determined from first-principles calculated total energy differences of spin-spiral states with oppositely rotating magnetizations in the presence of both the external field and spin-orbit coupling. The trend underlying the modifications is shown to be linked to orbital magnetism. The results demonstrate that an electric field may be a promising approach to manipulate macroscopically magnetic textures.

Domain Walls and Macroscopic Spin-Flip-Like States in GdxCo1-x/GdyCo1-y Bilayers

NASA Astrophysics Data System (ADS)

Martin, Jose I.

2005-03-01

Exchange coupled double layers (ECDL) made of rare earth -- transition metal amorphous alloys are of basic and technological interest, as they present different magnetization configurations when the composition is changed or when the temperature is varied crossing the compensation temperatures (Tcomp) of both ferrimagnetic alloys. In this work, amorphous GdxCo1-x(100 nm)/GdyCo1-y(100 nm) ECDL have been prepared to investigate the magnetization reversal and the stable magnetic configurations when the compositions of both layers are similar: x = 0.22, y = 0.24. The samples have been grown by co-sputtering on corning glass substrates, which has allowed to analyze the behaviour within each layer by transverse Kerr effect measurements. A rich variety of behaviours has been found in the temperature range between the Tcomp of both layers, including magnetization reversal by annihilation/creation of a Bloch wall across the sample thickness, and a macroscopic spin-flip-like metamagnetic state where the magnetic moments form a double antiferromagnetic state with the presence of a N'eel-like wall when the magnetizations of both layers are similar [1]. The whole observed behavior can be understood in terms of a deduced general magnetic field -- temperature phase diagram. [1] R. Morales et al. Phys. Rev. B 70, 174440 (2004). Work supported by Spanish CICYT.

Particle acceleration in explosive relativistic reconnection events and Crab Nebula gamma-ray flares

NASA Astrophysics Data System (ADS)

Lyutikov, Maxim; Komissarov, Serguei; Sironi, Lorenzo

2018-04-01

We develop a model of gamma-ray flares of the Crab Nebula resulting from the magnetic reconnection events in a highly magnetised relativistic plasma. We first discuss physical parameters of the Crab Nebula and review the theory of pulsar winds and termination shocks. We also review the principle points of particle acceleration in explosive reconnection events [Lyutikov et al., J. Plasma Phys., vol. 83(6), p. 635830601 (2017a); J. Plasma Phys., vol. 83(6), p. 635830602 (2017b)]. It is required that particles producing flares are accelerated in highly magnetised regions of the nebula. Flares originate from the poleward regions at the base of the Crab's polar outflow, where both the magnetisation and the magnetic field strength are sufficiently high. The post-termination shock flow develops macroscopic (not related to the plasma properties on the skin-depth scale) kink-type instabilities. The resulting large-scale magnetic stresses drive explosive reconnection events on the light-crossing time of the reconnection region. Flares are produced at the initial stage of the current sheet development, during the X-point collapse. The model has all the ingredients needed for Crab flares: natural formation of highly magnetised regions, explosive dynamics on the light travel time, development of high electric fields on macroscopic scales and acceleration of particles to energies well exceeding the average magnetic energy per particle.

High-frequency rapid B-mode ultrasound imaging for real-time monitoring of lesion formation and gas body activity during high-intensity focused ultrasound ablation.

PubMed

Gudur, Madhu Sudhan Reddy; Kumon, Ronald E; Zhou, Yun; Deng, Cheri X

2012-08-01

The goal of this study was to examine the ability of high-frame-rate, high-resolution imaging to monitor tissue necrosis and gas-body activities formed during high-intensity focused ultrasound (HIFU) application. Ex vivo porcine cardiac tissue specimens (n = 24) were treated with HIFU exposure (4.33 MHz, 77 to 130 Hz pulse repetition frequency (PRF), 25 to 50% duty cycle, 0.2 to 1 s, 2600 W/cm(2)). RF data from B-mode ultrasound imaging were obtained before, during, and after HIFU exposure at a frame rate ranging from 77 to 130 Hz using an ultrasound imaging system with a center frequency of 55 MHz. The time history of changes in the integrated backscatter (IBS), calibrated spectral parameters, and echo-decorrelation parameters of the RF data were assessed for lesion identification by comparison against gross sections. Temporal maximum IBS with +12 dB threshold achieved the best identification with a receiver-operating characteristic (ROC) curve area of 0.96. Frame-to-frame echo decorrelation identified and tracked transient gas-body activities. Macroscopic (millimeter-sized) cavities formed when the estimated initial expansion rate of gas bodies (rate of expansion in lateral-to-beam direction) crossed 0.8 mm/s. Together, these assessments provide a method for monitoring spatiotemporal evolution of lesion and gas-body activity and for predicting macroscopic cavity formation.

Fluctuation-enhanced electric conductivity in electrolyte solutions.

PubMed

Péraud, Jean-Philippe; Nonaka, Andrew J; Bell, John B; Donev, Aleksandar; Garcia, Alejandro L

2017-10-10

We analyze the effects of an externally applied electric field on thermal fluctuations for a binary electrolyte fluid. We show that the fluctuating Poisson-Nernst-Planck (PNP) equations for charged multispecies diffusion coupled with the fluctuating fluid momentum equation result in enhanced charge transport via a mechanism distinct from the well-known enhancement of mass transport that accompanies giant fluctuations. Although the mass and charge transport occurs by advection by thermal velocity fluctuations, it can macroscopically be represented as electrodiffusion with renormalized electric conductivity and a nonzero cation-anion diffusion coefficient. Specifically, we predict a nonzero cation-anion Maxwell-Stefan coefficient proportional to the square root of the salt concentration, a prediction that agrees quantitatively with experimental measurements. The renormalized or effective macroscopic equations are different from the starting PNP equations, which contain no cross-diffusion terms, even for rather dilute binary electrolytes. At the same time, for infinitely dilute solutions the renormalized electric conductivity and renormalized diffusion coefficients are consistent and the classical PNP equations with renormalized coefficients are recovered, demonstrating the self-consistency of the fluctuating hydrodynamics equations. Our calculations show that the fluctuating hydrodynamics approach recovers the electrophoretic and relaxation corrections obtained by Debye-Huckel-Onsager theory, while elucidating the physical origins of these corrections and generalizing straightforwardly to more complex multispecies electrolytes. Finally, we show that strong applied electric fields result in anisotropically enhanced "giant" velocity fluctuations and reduced fluctuations of salt concentration.

Fluctuation-enhanced electric conductivity in electrolyte solutions

PubMed Central

Péraud, Jean-Philippe; Nonaka, Andrew J.; Bell, John B.; Donev, Aleksandar; Garcia, Alejandro L.

2017-01-01

We analyze the effects of an externally applied electric field on thermal fluctuations for a binary electrolyte fluid. We show that the fluctuating Poisson–Nernst–Planck (PNP) equations for charged multispecies diffusion coupled with the fluctuating fluid momentum equation result in enhanced charge transport via a mechanism distinct from the well-known enhancement of mass transport that accompanies giant fluctuations. Although the mass and charge transport occurs by advection by thermal velocity fluctuations, it can macroscopically be represented as electrodiffusion with renormalized electric conductivity and a nonzero cation–anion diffusion coefficient. Specifically, we predict a nonzero cation–anion Maxwell–Stefan coefficient proportional to the square root of the salt concentration, a prediction that agrees quantitatively with experimental measurements. The renormalized or effective macroscopic equations are different from the starting PNP equations, which contain no cross-diffusion terms, even for rather dilute binary electrolytes. At the same time, for infinitely dilute solutions the renormalized electric conductivity and renormalized diffusion coefficients are consistent and the classical PNP equations with renormalized coefficients are recovered, demonstrating the self-consistency of the fluctuating hydrodynamics equations. Our calculations show that the fluctuating hydrodynamics approach recovers the electrophoretic and relaxation corrections obtained by Debye–Huckel–Onsager theory, while elucidating the physical origins of these corrections and generalizing straightforwardly to more complex multispecies electrolytes. Finally, we show that strong applied electric fields result in anisotropically enhanced “giant” velocity fluctuations and reduced fluctuations of salt concentration. PMID:28973890

A Novel Shape Memory Plate Osteosynthesis for Noninvasive Modulation of Fixation Stiffness in a Rabbit Tibia Osteotomy Model

PubMed Central

Müller, Christian W.; Pfeifer, Ronny; Meier, Karen; Decker, Sebastian; Reifenrath, Janin; Gösling, Thomas; Wesling, Volker; Krettek, Christian; Krämer, Manuel

2015-01-01

Nickel-titanium shape memory alloy (NiTi-SMA) implants might allow modulating fracture healing, changing their stiffness through alteration of both elastic modulus and cross-sectional shape by employing the shape memory effect (SME). Hypotheses: a novel NiTi-SMA plate stabilizes tibia osteotomies in rabbits. After noninvasive electromagnetic induction heating the alloy exhibits the SME and the plate changes towards higher stiffness (inverse dynamization) resulting in increased fixation stiffness and equal or better bony healing. In 14 rabbits, 1.0 mm tibia osteotomies were fixed with our experimental plate. Animals were randomised for control or induction heating at three weeks postoperatively. Repetitive X-ray imaging and in vivo measurements of bending stiffness were performed. After sacrifice at 8 weeks, macroscopic evaluation, µCT, and post mortem bending tests of the tibiae were carried out. One death and one early implant dislocation occurred. Following electromagnetic induction heating, radiographic and macroscopic changes of the implant proved successful SME activation. All osteotomies healed. In the treatment group, bending stiffness increased over time. Differences between groups were not significant. In conclusion, we demonstrated successful healing of rabbit tibia osteotomies using our novel NiTi-SMA plate. We demonstrated shape-changing SME in-vivo through transcutaneous electromagnetic induction heating. Thus, future orthopaedic implants could be modified without additional surgery. PMID:26167493

Microbiology of peritonsillar abscess in the South Estonian population

PubMed Central

Vaikjärv, Risto; Kasenõmm, Priit; Jaanimäe, Liis; Kivisild, Ave; Rööp, Tiiu; Sepp, Epp; Mändar, Reet

2016-01-01

Objective The first aim of this study was to compare the microbiota of different locations (pus, tonsillar fossa, blood) in peritonsillar abscess (PTA) patients in order to optimize the sampling scheme. The second aim was to estimate the occurrence of tonsillitis episodes and macroscopic oropharyngeal signs characteristic of recurrent tonsillitis in PTA patients. Methods The study group consisted of 22 consecutive patients with PTA undergoing bilateral tonsillectomy. The PTA was punctured; pus and tonsillar fossa biopsy samples and the peripheral blood cultures were collected. The index of tonsillitis was calculated by multiplying the number of tonsillitis episodes per year by the morbidity period in years. Macroscopic oropharyngeal signs were evaluated and they were as follows: tonsillar sclerosis, obstruction of the tonsillar crypts, scar tissue on tonsils, cryptic debris, and lymphatic tissue aggregates. Results The cultures of the pus were positive in 16 out of 22 patients and the cultures of the tonsillar fossa samples were positive in all cases. In total, 62 different organisms were found from tonsillar fossa, pus, and blood samples, which belonged to 5 different phyla and 18 different families. In the tonsillar fossa, the most frequent bacteria found were Streptococcus spp. In pus samples, the most frequently found bacteria were Streptococcus spp. and bacteria from the Streptococcus milleri group. Conclusion PTA patients had mixed anaerobic and aerobic microbiota both in the tissue of the tonsillar fossa and the pus of the peritonsillar space. We demonstrated that the tonsillar fossa specimen is a better material for microbiological analyses, because it reveals more bacteria per culture. PTA patients usually have a low number of tonsillitis episodes in their previous history, but a relatively high number of macroscopic oropharyngeal signs, indicating the sclerotic process in palatal tonsils. PMID:27113570

Restoration of an academic historical gross pathology collection-refreshed impact on current medical teaching?

PubMed

Eichhorn, Philip; Andraschke, Udo; Dross, Fritz; Geppert, Carol I; Hartmann, Arndt; Rau, Tilman T

2018-05-10

The declaration of Leiden pronounces the demand to conserve pathological-anatomical collections as cultural heritage. Likewise, the Institute of Pathology of the Friedrich-Alexander-University Erlangen-Nuremberg owns macroscopic pathological-anatomical specimens reaching back over 150 years. The purpose of this work is to examine the impact, meaning, and perception of such historical preparations during the current medical curriculum. Additionally, the experiences from the renovation process can be used as a template for other institutes. All preparations were documented, photographed, and catalogued in an electronic database. During a restoration period, a series of didactically suitable specimens were professionally restored. Hereby, the help of a special course of interested students was admitted. In a second step, the specimens were integrated into the regular teaching of students in macroscopic pathology. An evaluation was carried out on two student cohorts with and without historical specimens by means of a questionnaire with 23 items and two free text fields. In total, 1261 specimens were registered covering diseases from almost the complete human body with a strong representation of the cardiovascular, urinary, gastrointestinal, and central nervous systems. Hereby, exceptional rare and untreated cases with medical relevance could be found and stepwise implemented into the curriculum. The student evaluation positively addressed that the courses became livelier and interactive. Furthermore, a more comprehensive overview and a better understanding of the macroscopic pathology were appreciated. However, more self-study time with the specimen was demanded. The authenticity of historical specimens contrasts with the tendency to carry out virtual "online" didactic methods. The stereoscopic view on often untreated and, therefore, unbiased cases enhances a skill-oriented deeper understanding of diseases. In conclusion, historical specimens regain interest and even didactic value, especially in an era of declining autopsy rates.

Effects of cannabis on pulmonary structure, function and symptoms

PubMed Central

Aldington, Sarah; Williams, Mathew; Nowitz, Mike; Weatherall, Mark; Pritchard, Alison; McNaughton, Amanda; Robinson, Geoffrey; Beasley, Richard

2007-01-01

Background Cannabis is the most widely used illegal drug worldwide. Long‐term use of cannabis is known to cause chronic bronchitis and airflow obstruction, but the prevalence of macroscopic emphysema, the dose‐response relationship and the dose equivalence of cannabis with tobacco has not been determined. Methods A convenience sample of adults from the Greater Wellington region was recruited into four smoking groups: cannabis only, tobacco only, combined cannabis and tobacco and non‐smokers of either substance. Their respiratory status was assessed using high‐resolution CT (HRCT) scanning, pulmonary function tests and a respiratory and smoking questionnaire. Associations between respiratory status and cannabis use were examined by analysis of covariance and logistic regression. Results 339 subjects were recruited into the four groups. A dose‐response relationship was found between cannabis smoking and reduced forced expiratory volume in 1 s to forced vital capacity ratio and specific airways conductance, and increased total lung capacity. For measures of airflow obstruction, one cannabis joint had a similar effect to 2.5–5 tobacco cigarettes. Cannabis smoking was associated with decreased lung density on HRCT scans. Macroscopic emphysema was detected in 1/75 (1.3%), 15/92 (16.3%), 17/91 (18.9%) and 0/81 subjects in the cannabis only, combined cannabis and tobacco, tobacco alone and non‐smoking groups, respectively. Conclusions Smoking cannabis was associated with a dose‐related impairment of large airways function resulting in airflow obstruction and hyperinflation. In contrast, cannabis smoking was seldom associated with macroscopic emphysema. The 1:2.5–5 dose equivalence between cannabis joints and tobacco cigarettes for adverse effects on lung function is of major public health significance. PMID:17666437

Agreement between preoperative transvaginal ultrasound and intraoperative macroscopic examination for assessing myometrial infiltration in low-risk endometrioid carcinoma.

PubMed

Pineda, L; Alcázar, J L; Caparrós, M; Mínguez, J A; Idoate, M A; Quiceno, H; Solórzano, J L; Jurado, M

2016-03-01

To compare diagnostic performance of preoperative transvaginal ultrasound (TVS) and intraoperative macroscopic examination for determining myometrial infiltration in women with low-risk endometrial cancer, and to estimate the agreement between the two methods. This was a single-center observational study comprising women with preoperative diagnosis of well- or moderately differentiated endometrioid carcinoma of the endometrium. All women underwent preoperative TVS by a single examiner. According to the examiner's subjective impression, myometrial infiltration was stated as ≥ 50% or < 50%. Surgical staging was performed in all cases. Intraoperative macroscopic examination of the removed uterus was performed by pathologists who were unaware of the ultrasound findings, and myometrial infiltration was stated as ≥ 50% or < 50%. Definitive histological diagnosis of myometrial infiltration was made by frozen section analysis and was used as the gold standard. Sensitivity and specificity with 95% CIs were calculated for TVS and intraoperative macroscopic inspection and compared using McNemar's test. Agreement between TVS and intraoperative macroscopic inspection was estimated using Cohen's kappa index (κ) and percentage of agreement. Of 209 eligible women, 152 were ultimately included. Mean (± SD) age was 60.9 ± 10.2 years, with a range of 32-91 years. Definitive histological diagnosis revealed that myometrial infiltration was < 50% in 114 women and ≥ 50% in 38 women. Sensitivity and specificity of TVS for detecting deep myometrial infiltration were 81.6% and 89.5%, respectively, whereas the respective values for intraoperative macroscopic examination were 78.9% and 90.4% (McNemar's test, P > 0.05 when comparing TVS and intraoperative macroscopic examination). Agreement between methods was moderate with κ = 0.54 (95% CI, 0.39-0.69) and percentage of agreement of 82%. Although the agreement between preoperative TVS and intraoperative macroscopic examination for detecting deep myometrial infiltration was only moderate, both methods had similar accuracy when compared with frozen section histology. Preoperative TVS might reasonably be proposed as a method for assessing myometrial infiltration as an alternative to intraoperative macroscopic examination, especially when performed by an experienced examiner and image quality is not poor. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Quantum theory and human perception of the macro-world.

PubMed

Aerts, Diederik

2014-01-01

We investigate the question of 'why customary macroscopic entities appear to us humans as they do, i.e., as bounded entities occupying space and persisting through time', starting from our knowledge of quantum theory, how it affects the behavior of such customary macroscopic entities, and how it influences our perception of them. For this purpose, we approach the question from three perspectives. Firstly, we look at the situation from the standard quantum angle, more specifically the de Broglie wavelength analysis of the behavior of macroscopic entities, indicate how a problem with spin and identity arises, and illustrate how both play a fundamental role in well-established experimental quantum-macroscopical phenomena, such as Bose-Einstein condensates. Secondly, we analyze how the question is influenced by our result in axiomatic quantum theory, which proves that standard quantum theory is structurally incapable of describing separated entities. Thirdly, we put forward our new 'conceptual quantum interpretation', including a highly detailed reformulation of the question to confront the new insights and views that arise with the foregoing analysis. At the end of the final section, a nuanced answer is given that can be summarized as follows. The specific and very classical perception of human seeing-light as a geometric theory-and human touching-only ruled by Pauli's exclusion principle-plays a role in our perception of macroscopic entities as ontologically stable entities in space. To ascertain quantum behavior in such macroscopic entities, we will need measuring apparatuses capable of its detection. Future experimental research will have to show if sharp quantum effects-as they occur in smaller entities-appear to be ontological aspects of customary macroscopic entities. It remains a possibility that standard quantum theory is an incomplete theory, and hence incapable of coping ultimately with separated entities, meaning that a more general theory will be needed.

Complexity theory, time series analysis and Tsallis q-entropy principle part one: theoretical aspects

NASA Astrophysics Data System (ADS)

Pavlos, George P.

2017-12-01

In this study, we present the highlights of complexity theory (Part I) and significant experimental verifications (Part II) and we try to give a synoptic description of complexity theory both at the microscopic and at the macroscopic level of the physical reality. Also, we propose that the self-organization observed macroscopically is a phenomenon that reveals the strong unifying character of the complex dynamics which includes thermodynamical and dynamical characteristics in all levels of the physical reality. From this point of view, macroscopical deterministic and stochastic processes are closely related to the microscopical chaos and self-organization. The scientific work of scientists such as Wilson, Nicolis, Prigogine, Hooft, Nottale, El Naschie, Castro, Tsallis, Chang and others is used for the development of a unified physical comprehension of complex dynamics from the microscopic to the macroscopic level. Finally, we provide a comprehensive description of the novel concepts included in the complexity theory from microscopic to macroscopic level. Some of the modern concepts that can be used for a unified description of complex systems and for the understanding of modern complexity theory, as it is manifested at the macroscopic and the microscopic level, are the fractal geometry and fractal space-time, scale invariance and scale relativity, phase transition and self-organization, path integral amplitudes, renormalization group theory, stochastic and chaotic quantization and E-infinite theory, etc.

Intraoperative Consultation and Macroscopic Handling: The International Society of Urological Pathology (ISUP) Testicular Cancer Consultation Conference Recommendations.

PubMed

Verrill, Clare; Perry-Keene, Joanna; Srigley, John R; Zhou, Ming; Humphrey, Peter A; Lopez-Beltran, Antonio; Egevad, Lars; Ulbright, Thomas M; Tickoo, Satish K; Epstein, Jonathan I; Compérat, Eva; Berney, Daniel M

2018-06-01

The International Society of Urological Pathology held a conference on issues in testicular and penile pathology in Boston in March 2015, which included a presentation by the testis macroscopic features working group. The presentation focused on current published guidance for macroscopic handling of testicular tumors and retroperitoneal lymph node dissections with a summary of results from an online survey of members preceding the conference. The survey results were used to initiate discussions, but decisions on practice were made by expert consensus rather than voting. The importance of comprehensive assessment at the time of gross dissection with confirmation of findings by microscopic assessment was underscored. For example, the anatomic landmarks denoting the distinction of hilar soft tissue invasion (pT2) from spermatic cord invasion (pT3 category) can only be determined by careful macroscopic assessment in many cases. Other recommendations were to routinely sample epididymis, rete testis, hilar soft tissue, and tunica vaginalis in order to confirm macroscopic invasion of these structures or if not macroscopically evident, to exclude subtle microscopic invasion. Tumors 2 cm or less in greatest dimension should be completely embedded. If the tumor is >2 cm in greatest dimension, 10 blocks or a minimum of 1 to 2 additional blocks per centimeter should be taken (whichever is greater).

Advantages and challenges of microfluidic cell culture in polydimethylsiloxane devices.

PubMed

Halldorsson, Skarphedinn; Lucumi, Edinson; Gómez-Sjöberg, Rafael; Fleming, Ronan M T

2015-01-15

Culture of cells using various microfluidic devices is becoming more common within experimental cell biology. At the same time, a technological radiation of microfluidic cell culture device designs is currently in progress. Ultimately, the utility of microfluidic cell culture will be determined by its capacity to permit new insights into cellular function. Especially insights that would otherwise be difficult or impossible to obtain with macroscopic cell culture in traditional polystyrene dishes, flasks or well-plates. Many decades of heuristic optimization have gone into perfecting conventional cell culture devices and protocols. In comparison, even for the most commonly used microfluidic cell culture devices, such as those fabricated from polydimethylsiloxane (PDMS), collective understanding of the differences in cellular behavior between microfluidic and macroscopic culture is still developing. Moving in vitro culture from macroscopic culture to PDMS based devices can come with unforeseen challenges. Changes in device material, surface coating, cell number per unit surface area or per unit media volume may all affect the outcome of otherwise standard protocols. In this review, we outline some of the advantages and challenges that may accompany a transition from macroscopic to microfluidic cell culture. We focus on decisive factors that distinguish macroscopic from microfluidic cell culture to encourage a reconsideration of how macroscopic cell culture principles might apply to microfluidic cell culture. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

High-throughput imaging of adult fluorescent zebrafish with an LED fluorescence macroscope

PubMed Central

Blackburn, Jessica S; Liu, Sali; Raimondi, Aubrey R; Ignatius, Myron S; Salthouse, Christopher D; Langenau, David M

2011-01-01

Zebrafish are a useful vertebrate model for the study of development, behavior, disease and cancer. A major advantage of zebrafish is that large numbers of animals can be economically used for experimentation; however, high-throughput methods for imaging live adult zebrafish had not been developed. Here, we describe protocols for building a light-emitting diode (LED) fluorescence macroscope and for using it to simultaneously image up to 30 adult animals that transgenically express a fluorescent protein, are transplanted with fluorescently labeled tumor cells or are tagged with fluorescent elastomers. These protocols show that the LED fluorescence macroscope is capable of distinguishing five fluorescent proteins and can image unanesthetized swimming adult zebrafish in multiple fluorescent channels simultaneously. The macroscope can be built and used for imaging within 1 day, whereas creating fluorescently labeled adult zebrafish requires 1 hour to several months, depending on the method chosen. The LED fluorescence macroscope provides a low-cost, high-throughput method to rapidly screen adult fluorescent zebrafish and it will be useful for imaging transgenic animals, screening for tumor engraftment, and tagging individual fish for long-term analysis. PMID:21293462

Testing quantum mechanics against macroscopic realism using the output of {chi}{sup (2)} nonlinearity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Podoshvedov, Sergey A.; Kim, Jaewan

2006-09-15

We suggest an all-optical scheme to generate entangled superposition of a single photon with macroscopic entangled states for testing macroscopic realism. The scheme consists of source of single photons, a Mach-Zehnder interferometer in routes of which a system of coupled-down converters with type-I phase matching is inserted, and a beam splitter for the other auxiliary modes of the scheme. We use quantization of the pumping modes, depletion of the coherent states passing through the system, and interference effect in the pumping modes in the process of erasing which-path information of the single-photon on exit from the Mach-Zehnder interferometer. We showmore » the macroscopic fields of the output superposition are distinguishable states. This scheme generates macroscopic entangled state that violates Bell's inequality. Moreover, the detailed analysis concerning change of amplitudes of entangled superposition by means of repeating this process many times is accomplished. We show our scheme works without photon number resolving detection and it is robust to detector inefficiency.« less

Nonlocal correlations in a macroscopic measurement scenario

NASA Astrophysics Data System (ADS)

Kunkri, Samir; Banik, Manik; Ghosh, Sibasish

2017-02-01

Nonlocality is one of the main characteristic features of quantum systems involving more than one spatially separated subsystem. It is manifested theoretically as well as experimentally through violation of some local realistic inequality. On the other hand, classical behavior of all physical phenomena in the macroscopic limit gives a general intuition that any physical theory for describing microscopic phenomena should resemble classical physics in the macroscopic regime, the so-called macrorealism. In the 2-2-2 scenario (two parties, with each performing two measurements and each measurement having two outcomes), contemplating all the no-signaling correlations, we characterize which of them would exhibit classical (local realistic) behavior in the macroscopic limit. Interestingly, we find correlations which at the single-copy level violate the Bell-Clauser-Horne-Shimony-Holt inequality by an amount less than the optimal quantum violation (i.e., Cirel'son bound 2 √{2 } ), but in the macroscopic limit gives rise to a value which is higher than 2 √{2 } . Such correlations are therefore not considered physical. Our study thus provides a sufficient criterion to identify some of unphysical correlations.

A two scale modeling and computational framework for vibration-induced Raynaud syndrome.

PubMed

Hua, Yue; Lemerle, Pierre; Ganghoffer, Jean-François

2017-07-01

Hand-Arm Vibration syndrome (HAVS), usually caused by long-term use of hand-held power tools, can in certain manifestations alter the peripheral blood circulation in the hand-arm region. HAVS typically occurs after exposure to cold, causing an abnormally strong vasoconstriction of blood vessels. A pathoanatomical mechanism suggests that a reduction of the lumen of the blood vessels in VWF (Vibration White Finger) subjects, due to either hypertrophy or thickening of the vessel wall, may be at the origin of the disease. However, the direct and indirect effects of the load of the hand-held tools on the structure of blood vessels remain controversial:.one hypothesis is the mechanical action of vibration on the local acral dysregulation and/or on the vessel histomorphological modifications. Another hypothesis is the participation of the sympathetic nervous system to this dysregulation. In this paper, we assume the modifications as mechanobiological growth and the load-effect relationship may be interpreted as directly or indirectly induced. This work is the first attempt to model the effect of vibration through soft tissues onto the distal capillaries, addressing the double paradigm of multi space-time scales, i.e. low period vibration versus high time constant of the growth phenomenon as well as vibrations propagating in the macroscopic tissue including the microscopic capillary structures subjected to a pathological microstructural evolution. The objective is to lay down the theoretical basis of growth modeling for the small distal artery, with the ability to predict the geometrical and structural changes of the arterial walls caused by vibration exposure. We adopt the key idea of splitting the problem into one global vibration problem at the macroscopic scale and one local growth problem at the micro level. The macroscopic hyperelastic viscous dynamic model of the fingertip cross-section is validated by fitting experimental data. It is then used in steady-state vibration conditions to predict the mechanical fields in the close vicinity of capillaries. The space scale transfer from macroscopic to microscopic levels is ensured by considering a representative volume element (RVE) embedding a single capillary in its center. The vibrations emitted by the hand held power tool are next linked to the capillary growth through the adopted biomechanical growth model at the capillary level. The obtained results show that vibrations induce an increase of the thickness of the capillary's wall, thereby confirming the scenario of vibrations induced reduction of the lumen of blood vessels. Copyright © 2017 Elsevier Ltd. All rights reserved.

The use of many-body physics and thermodynamics to describe the dynamics of rhythmic generators in sensory cortices engaged in memory and learning.

PubMed

Vitiello, Giuseppe

2015-04-01

The problem of the transition from the molecular and cellular level to the macroscopic level of observed assemblies of myriads of neurons is the subject addressed in this report. The great amount of detailed information available at molecular and cellular level seems not sufficient to account for the high effectiveness and reliability observed in the brain macroscopic functioning. It is suggested that the dissipative many-body model and thermodynamics might offer the dynamical frame underlying the rich phenomenology observed at microscopic and macroscopic level and help in the understanding on how to fill the gap between the bio-molecular and cellular level and the one of brain macroscopic functioning. Copyright © 2014 Elsevier Ltd. All rights reserved.

Lattice gas simulations of dynamical geometry in one dimension.

PubMed

Love, Peter J; Boghosian, Bruce M; Meyer, David A

2004-08-15

We present numerical results obtained using a lattice gas model with dynamical geometry. The (irreversible) macroscopic behaviour of the geometry (size) of the lattice is discussed in terms of a simple scaling theory and obtained numerically. The emergence of irreversible behaviour from the reversible microscopic lattice gas rules is discussed in terms of the constraint that the macroscopic evolution be reproducible. The average size of the lattice exhibits power-law growth with exponent at late times. The deviation of the macroscopic behaviour from reproducibility for particular initial conditions ('rogue states') is investigated as a function of system size. The number of such 'rogue states' is observed to decrease with increasing system size. Two mean-field analyses of the macroscopic behaviour are also presented. Copyright 2004 The Royal Society

Analysis of structural patterns in the brain with the complex network approach

NASA Astrophysics Data System (ADS)

Maksimenko, Vladimir A.; Makarov, Vladimir V.; Kharchenko, Alexander A.; Pavlov, Alexey N.; Khramova, Marina V.; Koronovskii, Alexey A.; Hramov, Alexander E.

2015-03-01

In this paper we study mechanisms of the phase synchronization in a model network of Van der Pol oscillators and in the neural network of the brain by consideration of macroscopic parameters of these networks. As the macroscopic characteristics of the model network we consider a summary signal produced by oscillators. Similar to the model simulations, we study EEG signals reflecting the macroscopic dynamics of neural network. We show that the appearance of the phase synchronization leads to an increased peak in the wavelet spectrum related to the dynamics of synchronized oscillators. The observed correlation between the phase relations of individual elements and the macroscopic characteristics of the whole network provides a way to detect phase synchronization in the neural networks in the cases of normal and pathological activity.

Total and partial photoneutron cross sections for Pb isotopes

NASA Astrophysics Data System (ADS)

Kondo, T.; Utsunomiya, H.; Goriely, S.; Daoutidis, I.; Iwamoto, C.; Akimune, H.; Okamoto, A.; Yamagata, T.; Kamata, M.; Itoh, O.; Toyokawa, H.; Lui, Y.-W.; Harada, H.; Kitatani, F.; Hilaire, S.; Koning, A. J.

2012-07-01

Using quasimonochromatic laser-Compton scattering γ rays, total photoneutron cross sections were measured for 206,207,208Pb near neutron threshold with a high-efficiency 4π neutron detector. Partial E1 and M1 photoneutron cross sections along with total cross sections were determined for 207,208Pb at four energies near threshold by measuring anisotropies in photoneutron emission with linearly polarized γ rays. The E1 strength dominates over the M1 strength in the neutron channel where E1 photoneutron cross sections show extra strength of the pygmy dipole resonance in 207,208Pb near the neutron threshold corresponding to 0.32%-0.42% of the Thomas-Reiche-Kuhn sum rule. Several μN2 units of B(M1)↑ strength were observed in 207,208Pb just above neutron threshold, which correspond to an M1 cross section less than 10% of the total photoneutron cross section.

Dynamics of Large Systems of Nonlinearly Evolving Units

NASA Astrophysics Data System (ADS)

Lu, Zhixin

The dynamics of large systems of many nonlinearly evolving units is a general research area that has great importance for many areas in science and technology, including biology, computation by artificial neural networks, statistical mechanics, flocking in animal groups, the dynamics of coupled neurons in the brain, and many others. While universal principles and techniques are largely lacking in this broad area of research, there is still one particular phenomenon that seems to be broadly applicable. In particular, this is the idea of emergence, by which is meant macroscopic behaviors that "emerge" from a large system of many "smaller or simpler entities such that...large entities" [i.e., macroscopic behaviors] arise which "exhibit properties the smaller/simpler entities do not exhibit." In this thesis we investigate mechanisms and manifestations of emergence in four dynamical systems consisting many nonlinearly evolving units. These four systems are as follows. (a) We first study the motion of a large ensemble of many noninteracting particles in a slowly changing Hamiltonian system that undergoes a separatrix crossing. In such systems, we find that separatrix-crossing induces a counterintuitive effect. Specifically, numerical simulation of two sets of densely sprinkled initial conditions on two energy curves appears to suggest that the two energy curves, one originally enclosing the other, seemingly interchange their positions. This, however, is topologically forbidden. We resolve this paradox by introducing a numerical simulation method we call "robust" and study its consequences. (b) We next study the collective dynamics of oscillatory pacemaker neurons in Suprachiasmatic Nucleus (SCN), which, through synchrony, govern the circadian rhythm of mammals. We start from a high-dimensional description of the many coupled oscillatory neuronal units within the SCN. This description is based on a forced Kuramoto model. We then reduce the system dimensionality by using the Ott Antonsen Ansatz and obtain a low-dimensional macroscopic description. Using this reduced macroscopic system, we explain the east-west asymmetry of jet-lag recovery and discus the consequences of our findings. (c) Thirdly, we study neuron firing in integrate-and-fire neural networks. We build a discrete-state/discrete-time model with both excitatory and inhibitory neurons and find a phase transition between avalanching dynamics and ceaseless firing dynamics. Power-law firing avalanche size/duration distributions are observed at critical parameter values. Furthermore, in this critical regime we find the same power law exponents as those observed from experiments and previous, more restricted, simulation studies. We also employ a mean-field method and show that inhibitory neurons in this system promote robustness of the criticality (i.e., an enhanced range of system parameter where power-law avalanche statistics applies). (d) Lastly, we study the dynamics of "reservoir computing networks" (RCN's), which is a recurrent neural network (RNN) scheme for machine learning. The advantage of RCN's over traditional RNN's is that the training is done only on the output layer, usually via a simple least-square method. We show that RCN's are very effective for inferring unmeasured state variables of dynamical systems whose system state is only partially measured. Using the examples of the Lorenz system and the Rossler system we demonstrate the potential of an RCN to perform as an universal model-free "observer".

Macroscopic singlet oxygen model incorporating photobleaching as an input parameter

NASA Astrophysics Data System (ADS)

Kim, Michele M.; Finlay, Jarod C.; Zhu, Timothy C.

2015-03-01

A macroscopic singlet oxygen model for photodynamic therapy (PDT) has been used extensively to calculate the reacted singlet oxygen concentration for various photosensitizers. The four photophysical parameters (ξ, σ, β, δ) and threshold singlet oxygen dose ([1O2]r,sh) can be found for various drugs and drug-light intervals using a fitting algorithm. The input parameters for this model include the fluence, photosensitizer concentration, optical properties, and necrosis radius. An additional input variable of photobleaching was implemented in this study to optimize the results. Photobleaching was measured by using the pre-PDT and post-PDT sensitizer concentrations. Using the RIF model of murine fibrosarcoma, mice were treated with a linear source with fluence rates from 12 - 150 mW/cm and total fluences from 24 - 135 J/cm. The two main drugs investigated were benzoporphyrin derivative monoacid ring A (BPD) and 2-[1-hexyloxyethyl]-2-devinyl pyropheophorbide-a (HPPH). Previously published photophysical parameters were fine-tuned and verified using photobleaching as the additional fitting parameter. Furthermore, photobleaching can be used as an indicator of the robustness of the model for the particular mouse experiment by comparing the experimental and model-calculated photobleaching ratio.

Reflux oesophagitis and Helicobacter pylori infection in elderly patients.

PubMed Central

Liston, R.; Pitt, M. A.; Banerjee, A. K.

1996-01-01

Helicobacter pylori is associated with gastritis, peptic ulcers and gastric malignancies. Little attention has been paid to the possibility that it may also have a role in the pathogenesis of reflux oesophagitis. This is especially true in elderly patients who have life-long infection and provide an ideal group to study the mucosal changes associated with the organism. The aim of this study was to determine if H pylori is associated with reflux oesophagitis in elderly patients. Consecutive gastroscopy patients were recruited. Multiple biopsies were taken from oesophagus, stomach, antrum and duodenum for histology and rapid urease tests. Patients also had IgG ELISA antibodies and 13C-urea breath tests performed. Patients with macroscopic or microscopic evidence of reflux oesophagitis were compared to patients with macroscopically normal upper gastrointestinal tracts and no microscopic evidence of reflux. A total of 114 patients were recruited, average age 78.9 years (+/- 5.4). There were 37 refluxers and 33 non-refluxers. We found no evidence for an association between the presence of H pylori and reflux oesophagitis in elderly patients. The high prevalence of H pylori in patients with reflux oesophagitis can be explained by the presence of incidental gastritis. PMID:8733530

Chondromalacia patellae: an in vitro study. Comparison of MR criteria with histologic and macroscopic findings.

PubMed

van Leersum, M; Schweitzer, M E; Gannon, F; Finkel, G; Vinitski, S; Mitchell, D G

1996-11-01

To develop MR criteria for grades of chondromalacia patellae and to assess the accuracy of these grades. Fat-suppressed T2-weighted double-echo, fat-suppressed T2-weighted fast spin echo, fat-suppressed T1-weighted, and gradient echo sequences were performed at 1.5 T for the evaluation of chondromalacia. A total of 1000 MR, 200 histologic, and 200 surface locations were graded for chondromalacia and statistically compared. Compared with gross inspection as well as with histology the most accurate sequences were fat-suppressed T2-weighted conventional spin echo and fat suppressed T2-weighted fast spin echo, although the T1-weighted and proton density images also correlated well. The most accurate MR criteria applied to the severe grades of chondromalacia, with less accurate results for lesser grades. This study demonstrates that fat-suppressed routine T2-weighted and fast spin echo T2-weighted sequences seem to be more accurate than proton density, T1-weighted, and gradient echo sequences in grading chondromalacia. Good histologic and macroscopic correlation was seen in more severe grades of chondromalacia, but problems remain for the early grades in all sequences studied.

Heart rate reduction and longevity in mice.

PubMed

Gent, Sabine; Kleinbongard, Petra; Dammann, Philip; Neuhäuser, Markus; Heusch, Gerd

2015-03-01

Heart rate correlates inversely with life span across all species, including humans. In patients with cardiovascular disease, higher heart rate is associated with increased mortality, and such patients benefit from pharmacological heart rate reduction. However, cause-and-effect relationships between heart rate and longevity, notably in healthy individuals, are not established. We therefore prospectively studied the effects of a life-long pharmacological heart rate reduction on longevity in mice. We hypothesized, that the total number of cardiac cycles is constant, and that a 15% heart rate reduction might translate into a 15% increase in life span. C57BL6/J mice received either placebo or ivabradine at a dose of 50 mg/kg/day in drinking water from 12 weeks to death. Heart rate and body weight were monitored. Autopsy was performed on all non-autolytic cadavers, and parenchymal organs were evaluated macroscopically. Ivabradine reduced heart rate by 14% (median, interquartile range 12-15%) throughout life, and median life span was increased by 6.2% (p = 0.01). Body weight and macroscopic findings were not different between placebo and ivabradine. Life span was not increased to the same extent as heart rate was reduced, but nevertheless significantly prolonged by 6.2%.

Thick tumor capsule is a valuable risk factor for distant metastasis in follicular thyroid carcinoma.

PubMed

Shimbashi, Wataru; Sugitani, Iwao; Kawabata, Kazuyoshi; Mitani, Hiroki; Toda, Kazuhisa; Yamada, Keiko; Sato, Yukiko

2018-02-01

While the biological behavior of follicular thyroid carcinoma (FTC) has been studied in great detail using clinical experience, few studies have investigated pre- or intraoperative factors related to the risk of distant metastasis (DM) among patients with FTC. The aim of this study was to analyze the characteristics of FTC with DM. This study retrospectively investigated 102 patients with FTC who underwent surgery between 1988 and 2013. We compared clinicopathological characteristics between FTC with and without DM. Univariate analysis revealed nodal metastasis (p=0.045), serum thyroglobulin (Tg) at initial operation (≥1000ng/ml; p<0.0001), widely invasive appearance according to macroscopic findings (p<0.0001), thick tumor capsule (≥1mm; p<0.0001), vascular invasion (p=0.0003), extrathyroidal invasion (p=0.047), and venous tumor embolism (p=0.045) as significant risk factors for DM. Multivariate analysis conducted using pre- and intraoperative factors identified thick tumor capsule (≥1mm), serum Tg at initial operation (≥1000ng/ml), and macroscopically widely invasive appearance as risk factors independently associated with development of DM. Patients with these risk factors should undergo total thyroidectomy and radioactive iodine ablation. Copyright © 2017 Elsevier B.V. All rights reserved.

Matter-wave coherence limit owing to cosmic gravitational wave background

NASA Astrophysics Data System (ADS)

Steane, Andrew M.

2017-12-01

We study matter-wave interferometry in the presence of a stochastic background of gravitational waves. It is shown that if the background has a scale-invariant spectrum over a wide bandwidth (which is expected in a class of inflationary models of Big Bang cosmology), then separated-path interference cannot be observed for a lump of matter of size above a limit which is very insensitive to the strength and bandwidth of the fluctuations, unless the interferometer is servo-controlled or otherwise protected. For ordinary solid matter this limit is of order 1-10 mm. A servo-controlled or cross-correlated device would also exhibit limits to the observation of macroscopic interference, which we estimate for ordinary matter moving at speeds small compared to c.

Thermally Assisted Macroscopic Quantum Resonance on a Single-Crystal of Mn12-ac

NASA Astrophysics Data System (ADS)

Lionti, F.; Thomas, L.; Ballou, R.; Wernsdorfer, W.; Barbara, B.; Sulpice, A.; Sessoli, R.; Gatteschi, D.

1997-03-01

Magnetization measurements have been performed on a single mono-crystal of the molecule Mn12-acetate (L. Thomas, F. Lionti, R. Ballou, R. Sessoli, D. Gatteschi and B. Barbara, Nature, 383, 145 (1996).). Steps were observed in the hysteresis loop for values of the applied field at which level crossings of the collective spin states of each manganese clusters take place. The influence of quartic terms is taken into account. At these fields, the magnetization relaxes at short time scales, being otherwise essentially blocked. This novel behavior is interpreted in terms of resonant quantum tunneling of the magnetization from thermally activated energy levels. Hysteresis loop measurements performed for different field orientations and ac-susceptibility experiments, confirm general trends of this picture.

Derivation of Cumulus Cloud Dimensions and Shape from the Airborne Measurements by the Research Scanning Polarimeter

NASA Technical Reports Server (NTRS)

Alexandrov, Mikhail D.; Cairns, Brian; Emde, Claudia; Ackerman, Andrew S.; Ottaviani, Matteo; Wasilewski, Andrzej P.

2016-01-01

The Research Scanning Polarimeter (RSP) is an airborne instrument, whose measurements have been extensively used for retrievals of microphysical properties of clouds. In this study we show that for cumulus clouds the information content of the RSP data can be extended by adding the macroscopic parameters of the cloud, such as its geometric shape, dimensions, and height above the ground. This extension is possible by virtue of the high angular resolution and high frequency of the RSP measurements, which allow for geometric constraint of the cloud's 2D cross section between a number of tangent lines of view. The retrieval method is tested on realistic 3D radiative transfer simulations and applied to actual RSP data.

Far from Equilibrium Percolation, Stochastic and Shape Resonances in the Physics of Life

PubMed Central

Poccia, Nicola; Ansuini, Alessio; Bianconi, Antonio

2011-01-01

Key physical concepts, relevant for the cross-fertilization between condensed matter physics and the physics of life seen as a collective phenomenon in a system out-of-equilibrium, are discussed. The onset of life can be driven by: (a) the critical fluctuations at the protonic percolation threshold in membrane transport; (b) the stochastic resonance in biological systems, a mechanism that can exploit external and self-generated noise in order to gain efficiency in signal processing; and (c) the shape resonance (or Fano resonance or Feshbach resonance) in the association and dissociation processes of bio-molecules (a quantum mechanism that could play a key role to establish a macroscopic quantum coherence in the cell). PMID:22072921

Multifunctional Gold Nanostars for Molecular Imaging and Cancer Therapy

NASA Astrophysics Data System (ADS)

Liu, Yang; Yuan, Hsiangkuo; Fales, Andrew; Register, Janna; Vo-Dinh, Tuan

2015-08-01

Plasmonics-active gold nanoparticles offer excellent potential in molecular imaging and cancer therapy. Among them, gold nanostars (AuNS) exhibit cross-platform flexibility as multimodal contrast agents for macroscopic X-ray computer tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), as well as nanoprobes for photoacoustic tomography (PAT), two-photon photoluminescence (TPL) and surface-enhanced Raman spectroscopy (SERS). Their surfactant-free surface enables versatile functionalization to enhance cancer targeting, and allow triggered drug release. AuNS can also be used as an efficient platform for drug carrying, photothermal therapy, and photodynamic therapy. This review paper presents the latest progress regarding AuNS as a promising nanoplatform for cancer nanotheranostics. Future research directions with AuNS for biomedical applications will also be discussed.

Total reaction cross sections in CEM and MCNP6 at intermediate energies

DOE PAGES

Kerby, Leslie M.; Mashnik, Stepan G.

2015-05-14

Accurate total reaction cross section models are important to achieving reliable predictions from spallation and transport codes. The latest version of the Cascade Exciton Model (CEM) as incorporated in the code CEM03.03, and the Monte Carlo N-Particle transport code (MCNP6), both developed at Los Alamos National Laboratory (LANL), each use such cross sections. Having accurate total reaction cross section models in the intermediate energy region (50 MeV to 5 GeV) is very important for different applications, including analysis of space environments, use in medical physics, and accelerator design, to name just a few. The current inverse cross sections used inmore » the preequilibrium and evaporation stages of CEM are based on the Dostrovsky et al. model, published in 1959. Better cross section models are now available. Implementing better cross section models in CEM and MCNP6 should yield improved predictions for particle spectra and total production cross sections, among other results.« less

Total reaction cross sections in CEM and MCNP6 at intermediate energies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kerby, Leslie M.; Mashnik, Stepan G.

Accurate total reaction cross section models are important to achieving reliable predictions from spallation and transport codes. The latest version of the Cascade Exciton Model (CEM) as incorporated in the code CEM03.03, and the Monte Carlo N-Particle transport code (MCNP6), both developed at Los Alamos National Laboratory (LANL), each use such cross sections. Having accurate total reaction cross section models in the intermediate energy region (50 MeV to 5 GeV) is very important for different applications, including analysis of space environments, use in medical physics, and accelerator design, to name just a few. The current inverse cross sections used inmore » the preequilibrium and evaporation stages of CEM are based on the Dostrovsky et al. model, published in 1959. Better cross section models are now available. Implementing better cross section models in CEM and MCNP6 should yield improved predictions for particle spectra and total production cross sections, among other results.« less

Promising effect of Magliasa, a traditional Iranian formula, on experimental colitis on the basis of biochemical and cellular findings

PubMed Central

Rahimi, Roja; Baghaei, Amir; Baeeri, Maryam; Amin, Gholamreza; Shams-Ardekani, Mohammad Reza; Khanavi, Mahnaz; Abdollahi, Mohammad

2013-01-01

AIM: To investigate the efficacy of Magliasa, a traditional Iranian formula, on experimental colitis. METHODS: After botanical authentication of herbal ingredients, formulation of Magliasa, quantitative determination of total glucosinolates and total phenolic content, and analysis of the thin layer chromatography profile were performed. Colitis was then induced in male rats by instillation of 2,4,6-trinitrobenzenesulfonic acid (TNBS) in all groups, aside from the Sham group. The experimental groups consisted of: the Sham group that received only normal saline; the Mag-50, Mag-100 and Mag-200 groups, which received 50, 100 and 200 mg/kg per day of Magliasa, respectively; the control group, which received vehicle water orally; the infliximab group, which received infliximab (5 mg/kg per day, subcutaneously); and the Dexa group, which received dexamethasone (1 mg/kg per day, orally). After completing the treatment period (2 wk), the rats were sacrificed, the colon was removed, its macroscopic and microscopic changes were recorded, and tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), total antioxidant capacity, myeloperoxidase (MPO), and lipid peroxidation (LPO) were assessed in colon homogenate. RESULTS: The mean value of total glucosinolates in one gram of Magliasa was 19 ± 1 μmol. The mean value of the total phenolic content was 293.8 ± 17.6 mg gallic acid equivalents per 100 gram of Magliasa. Macroscopic scores were significantly decreased in Mag-100 (1.80 ± 0.58, P = 0.019) and Mag-200 (1.20 ± 0.20, P = 0.001) compared to the control group (3.40 ± 0.24), although some inflammation and hyperemia were evident. Treatment of rats by dexamethasone (0.33 ± 0.21, P < 0.001) and infliximab (0.83 ± 0.31, P < 0.001) remarkably attenuated scores where mild hyperemia was observed macroscopically. In comparison to the control group (4.00 ± 0.32), only Mag-200 (1.60 ± 0.40) showed a significant decrease in colonic histopathological scores (P = 0.005). Minimal mucosal inflammation was observed in the Dexa group (0.67 ± 0.21, P < 0.001). The levels of TNF-α, IL-1β and MPO were significantly lower in all groups compared to the controls (P < 0.05). A significant decrease in LPO was seen in the Mag-200 (3.27 ± 0.77, P = 0.01) and Dexa (3.44 ± 0.22, P = 0.011) groups in comparison to the control group (6.43 ± 0.61). Only dexamethasone caused a significant increase in antioxidant power in comparison to the control group (346.73 ± 9.9 vs 228.33 ± 2.75, P < 0.001). Infliximab and different doses of Magliasa did not show any remarkable increase in antioxidant capacity (P > 0.05). The effect of Magliasa in all of mentioned parameters, except antioxidant capacity, was dose dependent. CONCLUSION: The effects of Magliasa in TNBS-induced colitis are encouraging and warrant clinical trials for further confirmation. PMID:23569335

Macroscopic response in active nonlinear photonic crystals.

PubMed

Alagappan, Gandhi; John, Sajeev; Li, Er Ping

2013-09-15

We derive macroscopic equations of motion for the slowly varying electric field amplitude in three-dimensional active nonlinear optical nanostructures. We show that the microscopic Maxwell equations and polarization dynamics can be simplified to a macroscopic one-dimensional problem in the direction of group velocity. For a three-level active material, we derive the steady-state equations for normal mode frequency, threshold pumping, nonlinear Bloch mode amplitude, and lasing in photonic crystals. Our analytical results accurately recapture the results of exact numerical methods.

Neutron total cross section measurement at WNR. [215 to 250 MeV experimental techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lisowski, P.W.; Moore, M.S.; Morgan, G.L.

1979-01-01

The techniques involved in measuring fast-neutron total cross sections at the Weapons Neutron Facility (WNR) of the Los Alamos Scientific Laboratory are described. Results of total cross section measurements on natural carbon covering the range 2.5 to 250 MeV are presented. 16 references.

Single and double capture in F9+ + Ar collisions: Comparison of total capture with capture occurring from the Ar K shell

NASA Astrophysics Data System (ADS)

La Mantia, David; Kumara, Nuwan; Kayani, Asghar; Simon, Anna; Tanis, John

2016-05-01

Total cross sections for single and double capture, as well as the corresponding cross sections for capture resulting in the emission of an Ar K x ray, were measured. This work was performed at Western Michigan University with the use of the tandem Van de Graaff accelerator. A 45 MeV beam of fully-stripped fluorine ions was collided with argon gas molecules in a differentially pumped cell. Surface barrier detectors were used to observe the charge changed projectiles and a Si(Li) x-ray detector, placed at 90o to the incident beam, were used to measure coincidences with Ar K x rays. The total capture cross sections are compared to previously measured cross sections in the existing literature. The coincidence cross sections, considerably smaller than the total cross sections, are found to be nearly equal for single and double capture in contrast to the total cross sections, which vary by about an order of magnitude. Possible reasons for this behavior are discussed. Supported in part by the NSF.

CHARACTERISTICS OF RAT LIVER EXPOSED TO NANOPARTICLES OF LEAD COMPOUNDS.

PubMed

Omelchuk, S; Aleksijchuk, V; Sokurenko, L; Blagaia, A; Prudchenko, S

2016-12-01

In recent times, the lead becomes great importance in environmental pollution, including its nanoparticles. In the literature, there is little data on the changes in the liver after the exposure with lead nanoparticles. The purpose of this study was the identification and determination of macroscopic, microscopic, and biochemical changes of the structural elements of the rat's liver exposed to the action of lead compounds. The study was carried out on 60 male Wistar rats. The first and second groups of animals were intraperitoneally injected with colloidal solution of nanoparticles of Lead Sulfide size of 10 nm and 30 nm, and the third group was intraperitoneally injected with a solution of nitrate lead. Macroscopic, histological, histochemical, biochemical methods and gas chromatography were used to identify the changes of fatty acids metabolism. The experiment has found that body weights of animals in all tested groups were decreased after 6 weeks of lead nanoparticles injection, while relative liver weight was increased. Levels of total lipids and cholesterol, total protein and albumin in the blood serum in study groups have decreased, and the level of triglycerides and glucose have increased. Moderate dystrophic changes were observed in the histological examinations of the liver, and this was confirmed by morphometric and densitometric parameters. Changes of fatty acid composition of lipids of the liver exposed to nanoparticles were the result of increasing arachidonic fatty acid content and reduction of the stearic fatty acid content. Thus, it has been proven by the experiment that the effect of lead nanoparticles depends on their size.

Macroscopic Rotator Cuff Tendinopathy and Histopathology Do Not Predict Repair Outcomes of Rotator Cuff Tears.

PubMed

Sethi, Paul M; Sheth, Chirag D; Pauzenberger, Leo; McCarthy, Mary Beth R; Cote, Mark P; Soneson, Emma; Miller, Seth; Mazzocca, Augustus D

2018-03-01

Numerous studies have identified factors that may affect the chances of rotator cuff healing after surgery. Intraoperative tendon quality may be used to predict healing and to determine type of repair and/or consideration of augmentation. There are no data that correlate how gross tendon morphology and degree of tendinopathy affect patient outcome or postoperative tendon healing. Purpose/Hypothesis: The purposes of this study were to (1) compare the gross appearance of the tendon edge during arthroscopic rotator cuff repair with its histological degree of tendinopathy and (2) determine if gross appearance correlated with postoperative repair integrity. The hypothesis was that gross (macroscopic) tendon with normal thickness, no delamination, and elastic tissue before repair would have a correlation with low Bonar scores, higher postoperative American Shoulder and Elbow Surgeons (ASES) scores, and increased rates of postoperative tendon healing on ultrasound. Cross-sectional study; Level of evidence, 3. A total of 105 patients undergoing repair of medium-size (1-3 cm) full-thickness rotator cuff tears were enrolled in the study. Intraoperatively, the supraspinatus tendon was rated on thickness, fraying, and stiffness. Tendon tissue was recovered for histological analysis based on the Bonar scoring system. Postoperative ASES and ultrasound assessment of healing were obtained 1 year after repair. Correlation between gross appearance of the tendon and rotator cuff histology was determined. Of the 105 patients, 85 were followed the study to completion. The mean age of the patients was 61.6 years; Bonar score, 7.5; preoperative ASES score, 49; and postoperative ASES score, 86. Ninety-one percent of repairs were intact on ultrasound. Gross appearance of torn rotator cuff tendon tissue did not correlate with histological appearance. Neither histological (Bonar) score nor gross appearance correlated with multivariate analysis of ASES score, postoperative repair status, or demographic data. The degree of tendinopathy did not correlate with morphological appearance of the tendon. Neither of these parameters correlated with healing or patient outcome. This study suggests that the degree of tendinopathy, unlike muscle atrophy, may not be predictive of outcomes and that, on appearance, poor quality tendon has adequate healing capacity. Therefore, abnormal gross tendon appearance should not affect the repair effort or technique.

Validation of the WIMSD4M cross-section generation code with benchmark results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deen, J.R.; Woodruff, W.L.; Leal, L.E.

1995-01-01

The WIMSD4 code has been adopted for cross-section generation in support of the Reduced Enrichment Research and Test Reactor (RERTR) program at Argonne National Laboratory (ANL). Subsequently, the code has undergone several updates, and significant improvements have been achieved. The capability of generating group-collapsed micro- or macroscopic cross sections from the ENDF/B-V library and the more recent evaluation, ENDF/B-VI, in the ISOTXS format makes the modified version of the WIMSD4 code, WIMSD4M, very attractive, not only for the RERTR program, but also for the reactor physics community. The intent of the present paper is to validate the WIMSD4M cross-section librariesmore » for reactor modeling of fresh water moderated cores. The results of calculations performed with multigroup cross-section data generated with the WIMSD4M code will be compared against experimental results. These results correspond to calculations carried out with thermal reactor benchmarks of the Oak Ridge National Laboratory (ORNL) unreflected HEU critical spheres, the TRX LEU critical experiments, and calculations of a modified Los Alamos HEU D{sub 2}O moderated benchmark critical system. The benchmark calculations were performed with the discrete-ordinates transport code, TWODANT, using WIMSD4M cross-section data. Transport calculations using the XSDRNPM module of the SCALE code system are also included. In addition to transport calculations, diffusion calculations with the DIF3D code were also carried out, since the DIF3D code is used in the RERTR program for reactor analysis and design. For completeness, Monte Carlo results of calculations performed with the VIM and MCNP codes are also presented.« less

Validation of the WIMSD4M cross-section generation code with benchmark results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leal, L.C.; Deen, J.R.; Woodruff, W.L.

1995-02-01

The WIMSD4 code has been adopted for cross-section generation in support of the Reduced Enrichment for Research and Test (RERTR) program at Argonne National Laboratory (ANL). Subsequently, the code has undergone several updates, and significant improvements have been achieved. The capability of generating group-collapsed micro- or macroscopic cross sections from the ENDF/B-V library and the more recent evaluation, ENDF/B-VI, in the ISOTXS format makes the modified version of the WIMSD4 code, WIMSD4M, very attractive, not only for the RERTR program, but also for the reactor physics community. The intent of the present paper is to validate the procedure to generatemore » cross-section libraries for reactor analyses and calculations utilizing the WIMSD4M code. To do so, the results of calculations performed with group cross-section data generated with the WIMSD4M code will be compared against experimental results. These results correspond to calculations carried out with thermal reactor benchmarks of the Oak Ridge National Laboratory(ORNL) unreflected critical spheres, the TRX critical experiments, and calculations of a modified Los Alamos highly-enriched heavy-water moderated benchmark critical system. The benchmark calculations were performed with the discrete-ordinates transport code, TWODANT, using WIMSD4M cross-section data. Transport calculations using the XSDRNPM module of the SCALE code system are also included. In addition to transport calculations, diffusion calculations with the DIF3D code were also carried out, since the DIF3D code is used in the RERTR program for reactor analysis and design. For completeness, Monte Carlo results of calculations performed with the VIM and MCNP codes are also presented.« less

Production and cross-sectional characterization of aligned co-electrospun hollow microfibrous bulk assemblies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Feng-Lei; The School of Materials, The University of Manchester, Manchester M13 9PL; CRUK-EPSRC Cancer Imaging Centre in Cambridge and Manchester

2015-11-15

The development of co-electrospun (co-ES) hollow microfibrous assemblies of an appreciable thickness is critical for many practical applications, including filtration membranes and tissue-mimicking scaffolds. In this study, thick uniaxially aligned hollow microfibrous assemblies forming fiber bundles and strips were prepared by co-ES of polycaprolactone (PCL) and polyethylene oxide (PEO) as shell and core materials, respectively. Hollow microfiber bundles were deposited on a fixed rotating disc, which resulted in non-controllable cross-sectional shapes on a macroscopic scale. In comparison, fiber strips were produced with tuneable thickness and width by additionally employing an x–y translation stage in co-ES. Scanning electron microscopy (SEM) imagesmore » of cross-sections of fiber assemblies were analyzed to investigate the effects of production time (from 0.5 h to 12 h), core flow rate (from 0.8 mL/h to 2.0 mL/h) and/or translation speed (from 0.2 mm/s to 5 mm/s) on the pores and porosity. We observed significant changes in pore size and shape with core flow rate but the influence of production time varied; five strips produced under the same conditions had reasonably good size and porosity reproducibility; pore sizes didn't vary significantly from strip bottom to surface, although the porosity gradually decreased and then returned to the initial level. - Highlights: • Hollow microfibrous assemblies based on co-electrospinning are demonstrated. • The thickness and width of co-electrospun strips were controllable. • Cross-sections of fibres had non-normally distributed pore sizes and shapes. • Cross-sections were significantly influenced by production time and flow rate. • Co-electrospun strips had reasonably good reproducible cross-sections.« less

Cross transmission of gastrointestinal nematodes between captive neotropical felids and feral cats.

PubMed

Rendón-Franco, Emilio; Romero-Callejas, Evangelina; Villanueva-García, Claudia; Osorio-Sarabia, David; Muñoz-García, Claudia I

2013-12-01

Pathogen cross transmission between wildlife and domestic animals represents an extinction risk for wildlife; however, reliable verification is difficult to perform, and in some cases, it is even considered unlikely to be conducted. The aim of this work was to identify cross transmission of helminths between feral cats and captive wild felids at a zoological park in southeastern Mexico. Feces were collected from jaguars (Panthera onca), cougars (Puma concolor), ocelots (Leopardus pardalis), margays (Leopardus wiedii), and jaguarundis (Puma yagouaroundi). A flotation technique and macroscopic sieving were performed on the feces. Additionally, as part of the noxious fauna control program of the park, feral cats were captured and euthanized. To perform parasitologic studies, helminths from these animals were recovered. Toxocara cati and Trichuris campanula were shared by jaguarundis and feral cats. Ancylostoma sp. was found in jaguar and ocelot and Ancylostoma tubaeforme in feral cats. Additionally, during this study, a couple of jaguarundis died with clinical signs of trichuriasis. This is the first report of T. campanula in jaguarundi. Because feral cats roam freely in the park, transmission could occur from these vertebrates to wild felids. This study shows the risk that parasites represent to wild felids; a similar situation could be found in free-living species, especially in fragmented habitats that favor contact with domestic animals.

Low-energy and very-low energy total cross sections for electron collisions with N2

NASA Astrophysics Data System (ADS)

Kitajima, Masashi; Kishino, Takaya; Okumura, Takuma; Kobayashi, Naomasa; Sayama, Atsushi; Mori, Yuma; Hosaka, Kouichi; Odagiri, Takeshi; Hoshino, Masamitsu; Tanaka, Hiroshi

2017-06-01

Absolute grand total cross sections for electron scattering from N2 are obtained in the energy range from 20 eV down to 5 meV with very narrow electron energy width of 9 meV using the threshold-photoelectron source. Total cross sections obtained in the present study are compared with the previous experimentally obtained results. At the very-low energy region below 50 meV, the present total cross sections are somewhat smaller than those reported by the Aarhus group [S.V. Hoffmann et al., Rev. Sci. Instrum. 73, 4157 (2002)], which has been the only experimental work that provided the total cross sections in the very-low energy region. The energy positions of the peaks in the total cross sections due to the 2Πg shape resonance are obtained with higher accuracy, due to the improved uncertainty of the energy position in the present measurement compared to the previous works. The resonance structure in the total cross sections due to the Feshbach resonances of N2 at around 11.5 eV are also observed. Analysis of the resonant structure was carried out in order to determine the values of resonance width of Feshbach resonances of N2. Contribution to the Topical Issue: "Atomic and Molecular Data and their Applications", edited by Gordon W.F. Drake, Jung-Sik Yoon, Daiji Kato, Grzegorz Karwasz.

Nanoplasmon-enabled macroscopic thermal management

PubMed Central

Jonsson, Gustav Edman; Miljkovic, Vladimir; Dmitriev, Alexandre

2014-01-01

In numerous applications of energy harvesting via transformation of light into heat the focus recently shifted towards highly absorptive nanoplasmonic materials. It is currently established that noble metals-based absorptive plasmonic platforms deliver significant light-capturing capability and can be viewed as super-absorbers of optical radiation. Naturally, approaches to the direct experimental probing of macroscopic temperature increase resulting from these absorbers are welcomed. Here we derive a general quantitative method of characterizing heat-generating properties of optically absorptive layers via macroscopic thermal imaging. We further monitor macroscopic areas that are homogeneously heated by several degrees with nanostructures that occupy a mere 8% of the surface, leaving it essentially transparent and evidencing significant heat generation capability of nanoplasmon-enabled light capture. This has a direct bearing to a large number of applications where thermal management is crucial. PMID:24870613

Estimation of macroscopic elastic characteristics for hierarchical anisotropic solids based on probabilistic approach

NASA Astrophysics Data System (ADS)

Smolina, Irina Yu.

2015-10-01

Mechanical properties of a cable are of great importance in design and strength calculation of flexible cables. The problem of determination of elastic properties and rigidity characteristics of a cable modeled by anisotropic helical elastic rod is considered. These characteristics are calculated indirectly by means of the parameters received from statistical processing of experimental data. These parameters are considered as random quantities. With taking into account probable nature of these parameters the formulas for estimation of the macroscopic elastic moduli of a cable are obtained. The calculating expressions for macroscopic flexural rigidity, shear rigidity and torsion rigidity using the macroscopic elastic characteristics obtained before are presented. Statistical estimations of the rigidity characteristics of some cable grades are adduced. A comparison with those characteristics received on the basis of deterministic approach is given.

Routine histological analysis of a macroscopically normal gallbladder--a review of the literature.

PubMed

Jamal, K; Ratansingham, K; Siddique, M; Nehra, D

2014-01-01

70,000 cholecystectomies were performed in the United Kingdom in 2011-2012. Currently it is standard practice to submit all gallbladder specimens for routine histology to exclude malignancy. The aim of this systematic review was to establish whether a normal macroscopic appearance to the gallbladder at the time of cholecystectomy is sufficient to rule out malignancy and therefore negate the need for routine histology. Relevant articles that were published between 1966 and January 2013 were identified through electronic databases. 21 studies reported on 34,499 histologically analysed specimens. 172/187 (92%) of gallbladder cancers demonstrated intra-operative macroscopic abnormality. Studies that opened the specimens intra-operatively identified all cancers, whereas gross macroscopic visualization resulted in 15 potentially missed cancers (p = 0.10). In patients of European ethnicity, gallbladder cancer in a macroscopically normal looking gallbladder was identified in only one study; however all of these patients were above the age of 60. The incidence of gallbladder cancer was significantly raised in ethnic groups from high risk areas (p = 0.0001). A macroscopically normal gallbladder in patients of European ethnicity under the age of 60 may not require formal histopathology. The best method for intra-operative examination may involve opening the specimen to allow inspection of the mucosa and wall, however this needs further investigation. In the context of the volume of gallbladder surgery being performed there is the potential for significant cost and time savings. Copyright © 2014 Surgical Associates Ltd. All rights reserved.

Motion immune diffusion imaging using augmented MUSE (AMUSE) for high-resolution multi-shot EPI

PubMed Central

Guhaniyogi, Shayan; Chu, Mei-Lan; Chang, Hing-Chiu; Song, Allen W.; Chen, Nan-kuei

2015-01-01

Purpose To develop new techniques for reducing the effects of microscopic and macroscopic patient motion in diffusion imaging acquired with high-resolution multi-shot EPI. Theory The previously reported Multiplexed Sensitivity Encoding (MUSE) algorithm is extended to account for macroscopic pixel misregistrations as well as motion-induced phase errors in a technique called Augmented MUSE (AMUSE). Furthermore, to obtain more accurate quantitative DTI measures in the presence of subject motion, we also account for the altered diffusion encoding among shots arising from macroscopic motion. Methods MUSE and AMUSE were evaluated on simulated and in vivo motion-corrupted multi-shot diffusion data. Evaluations were made both on the resulting imaging quality and estimated diffusion tensor metrics. Results AMUSE was found to reduce image blurring resulting from macroscopic subject motion compared to MUSE, but yielded inaccurate tensor estimations when neglecting the altered diffusion encoding. Including the altered diffusion encoding in AMUSE produced better estimations of diffusion tensors. Conclusion The use of AMUSE allows for improved image quality and diffusion tensor accuracy in the presence of macroscopic subject motion during multi-shot diffusion imaging. These techniques should facilitate future high-resolution diffusion imaging. PMID:25762216

Breakdown of the Debye approximation for the acoustic modes with nanometric wavelengths in glasses

PubMed Central

Monaco, Giulio; Giordano, Valentina M.

2009-01-01

On the macroscopic scale, the wavelengths of sound waves in glasses are large enough that the details of the disordered microscopic structure are usually irrelevant, and the medium can be considered as a continuum. On decreasing the wavelength this approximation must of course fail at one point. We show here that this takes place unexpectedly on the mesoscopic scale characteristic of the medium range order of glasses, where it still works well for the corresponding crystalline phases. Specifically, we find that the acoustic excitations with nanometric wavelengths show the clear signature of being strongly scattered, indicating the existence of a cross-over between well-defined acoustic modes for larger wavelengths and ill-defined ones for smaller wavelengths. This cross-over region is accompanied by a softening of the sound velocity that quantitatively accounts for the excess observed in the vibrational density of states of glasses over the Debye level at energies of a few milli-electronvolts. These findings thus highlight the acoustic contribution to the well-known universal low-temperature anomalies found in the specific heat of glasses. PMID:19240211

Effect of the size of experimental channels of the lead slowing-down spectrometer SVZ-100 (Institute for Nuclear Research, Moscow) on the moderation constant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Latysheva, L. N.; Bergman, A. A.; Sobolevsky, N. M., E-mail: sobolevs@inr.ru

Lead slowing-down (LSD) spectrometers have a low energy resolution (about 30%), but their luminosity is 10{sup 3} to 10{sup 4} times higher than that of time-of-flight (TOF) spectrometers. A high luminosity of LSD spectrometers makes it possible to use them to measure neutron cross section for samples of mass about several micrograms. These features specify a niche for the application of LSD spectrometers in measuring neutron cross sections for elements hardly available in macroscopic amounts-in particular, for actinides. A mathematical simulation of the parameters of SVZ-100 LSD spectrometer of the Institute for Nuclear Research (INR, Moscow) is performed in themore » present study on the basis of the MCNPX code. It is found that the moderation constant, which is the main parameter of LSD spectrometers, is highly sensitive to the size and shape of detecting volumes in calculations and, hence, to the real size of experimental channels of the LSD spectrometer.« less

Force per cross-sectional area from molecules to muscles: a general property of biological motors

PubMed Central

Meyer-Vernet, Nicole

2016-01-01

We propose to formally extend the notion of specific tension, i.e. force per cross-sectional area—classically used for muscles, to quantify forces in molecular motors exerting various biological functions. In doing so, we review and compare the maximum tensions exerted by about 265 biological motors operated by about 150 species of different taxonomic groups. The motors considered range from single molecules and motile appendages of microorganisms to whole muscles of large animals. We show that specific tensions exerted by molecular and non-molecular motors follow similar statistical distributions, with in particular, similar medians and (logarithmic) means. Over the 1019 mass (M) range of the cell or body from which the motors are extracted, their specific tensions vary as Mα with α not significantly different from zero. The typical specific tension found in most motors is about 200 kPa, which generalizes to individual molecular motors and microorganisms a classical property of macroscopic muscles. We propose a basic order-of-magnitude interpretation of this result. PMID:27493785

Corneal Cross-Linking Has No Effect on Matrix Metalloproteinase 9 and 13 Levels During Fungal Keratitis on the Early Stage.

PubMed

Kalkanci, Ayse; Bilgihan, Kamil; Ozdemir, Huseyin Baran; Yar Saglam, Atiye Seda; Karakurt, Funda; Erdogan, Merve

2018-04-01

The aim of our study was to investigate matrix metalloproteinases, MMP-9 and MMP-13 levels, in the rabbit model of Fusarium and Candida keratitis treated by corneal cross-linking (PACK-CXL). Rabbit corneas were inoculated with fungal inoculum for keratitis. Each group divided into four subgroups, including un-treated group, PACK-CXL group, voriconazole group and PACK-CXL plus voriconazole group. PACK-CXL was applied with 0.25% riboflavin in accelerated Dresden protocol, and 0.1% voriconazole drops were administered. All corneal buttons excised at tenth day after ophthalmological examination. Fungal cell counts and Scheiber scores were determined in all groups. Corneal tissue MMP mRNA levels were evaluated quantitative reverse transcriptase PCR. The difference in MMP-9 and MMP-13 levels at all groups was not statistically significant (p > 0.05). PACK-CXL with 0.25% riboflavin either alone or combined with antifungal drops was unable to provide decline in inflammatory findings in both macroscopic and microscopic levels similar to medical antifungal treatment.

Dually actuated triple shape memory polymers of cross-linked polycyclooctene-carbon nanotube/polyethylene nanocomposites.

PubMed

Wang, Zhenwen; Zhao, Jun; Chen, Min; Yang, Minhao; Tang, Luyang; Dang, Zhi-Min; Chen, Fenghua; Huang, Miaoming; Dong, Xia

2014-11-26

In this work, electrically and thermally actuated triple shape memory polymers (SMPs) of chemically cross-linked polycyclooctene (PCO)-multiwalled carbon nanotube (MWCNT)/polyethylene (PE) nanocomposites with co-continuous structure and selective distribution of fillers in PCO phase are prepared. We systematically studied not only the microstructure including morphology and fillers' selective distribution in one phase of the PCO/PE blends, but also the macroscopic properties including thermal, mechanical, and electrical properties. The co-continuous window of the immiscible PCO/PE blends is found to be the volume fraction of PCO (vPCO) of ca. 40-70 vol %. The selective distribution of fillers in one phase of co-continuous blends is obtained by a masterbatch technique. The prepared triple SMP materials show pronounced triple shape memory effects (SMEs) on the dynamic mechanical thermal analysis (DMTA) and the visual observation by both thermal and electric actuations. Such polyolefin samples with well-defined microstructure, electrical actuation, and triple SMEs might have potential applications as, for example, multiple autochoke elements for engines, self-adjusting orthodontic wires, and ophthalmic devices.

Radiative transfer in a sphere illuminated by a parallel beam - An integral equation approach. [in planetary atmosphere

NASA Technical Reports Server (NTRS)

Shia, R.-L.; Yung, Y. L.

1986-01-01

The problem of multiple scattering of nonpolarized light in a planetary body of arbitrary shape illuminated by a parallel beam is formulated using the integral equation approach. There exists a simple functional whose stationarity condition is equivalent to solving the equation of radiative transfer and whose value at the stationary point is proportional to the differential cross section. The analysis reveals a direct relation between the microscopic symmetry of the phase function for each scattering event and the macroscopic symmetry of the differential cross section for the entire planetary body, and the interconnection of these symmetry relations and the variational principle. The case of a homogeneous sphere containing isotropic scatterers is investigated in detail. It is shown that the solution can be expanded in a multipole series such that the general spherical problem is reduced to solving a set of decoupled integral equations in one dimension. Computations have been performed for a range of parameters of interest, and illustrative examples of applications to planetary problems as provided.

Calculation of total electron excitation cross-sections and partial electron ionization cross-sections for the elements. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Green, T. J.

1973-01-01

Computer programs were used to calculate the total electron excitation cross-section for atoms and the partial ionization cross-section. The approximations to the scattering amplitude used are as follows: (1) Born, Bethe, and Modified Bethe for non-exchange excitation; (2) Ochkur for exchange excitation; and (3) Coulomb-Born of non-exchange ionization. The amplitudes are related to the differential cross-sections which are integrated to give the total excitation (or partial ionization) cross-section for the collision. The atomic wave functions used are Hartree-Fock-Slater functions for bound states and the coulomb wave function for the continuum. The programs are presented and the results are examined.

Nucleon-Nucleon Total Cross Section

NASA Technical Reports Server (NTRS)

Norbury, John W.

2008-01-01

The total proton-proton and neutron-proton cross sections currently used in the transport code HZETRN show significant disagreement with experiment in the GeV and EeV energy ranges. The GeV range is near the region of maximum cosmic ray intensity. It is therefore important to correct these cross sections, so that predictions of space radiation environments will be accurate. Parameterizations of nucleon-nucleon total cross sections are developed which are accurate over the entire energy range of the cosmic ray spectrum.

Economic burden of advanced melanoma in France, Germany and the UK: a retrospective observational study (Melanoma Burden-of-Illness Study).

PubMed

Grange, Florent; Mohr, Peter; Harries, Mark; Ehness, Rainer; Benjamin, Laure; Siakpere, Obukohwo; Barth, Janina; Stapelkamp, Ceilidh; Pfersch, Sylvie; McLeod, Lori D; Kaye, James A; Wolowacz, Sorrel; Kontoudis, Ilias

2017-12-01

The aim of this study was to estimate the cost-of-illness associated with completely resected stage IIIB/IIIC melanoma with macroscopic lymph node involvement, overall and by disease phase, in France, Germany and the UK. This retrospective observational study included patients aged older than or equal to 18 years first diagnosed with stage IIIB/IIIC cutaneous melanoma between 1 January 2009 and 31 December 2011. Data were obtained from medical records and a patient survey. Direct costs, indirect costs and patient out-of-pocket expenses were estimated in euros (€) (and British pounds, £) by collecting resource use and multiplying by country-specific unit costs. National annual costs were estimated using national disease prevalence from the European cancer registry and other published data. Forty-nine centres provided data on 558 patients (58.2% aged <65 years, 53.6% stage IIIB disease at diagnosis). The mean follow-up duration was 27 months (France), 26 months (Germany) and 22 months (UK). The mean total direct cost per patient during follow-up was €23 582 in France, €32 058 in Germany and €37 970 (£31 123) in the UK. The largest cost drivers were melanoma drugs [mean €14 004, €21 269, €29 750 (£24 385), respectively] and hospitalization/emergency treatment [mean: €6634, €6950, €3449 (£2827), respectively]. The total mean indirect costs per patient were €129 (France), €4,441 (Germany) and €1712 (£1427) (UK). Estimates for annual national direct cost were €13.1 million (France), €30.2 million (Germany) and €27.8 (£22.8) million (UK). The economic burden of stage IIIB/IIIC melanoma with macroscopic lymph node involvement was substantial in all three countries. Total direct costs were the highest during the period with distant metastasis/terminal illness.

Causality as an emergent macroscopic phenomenon: The Lee-Wick O(N) model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grinstein, Benjamin; O'Connell, Donal; Wise, Mark B.

2009-05-15

In quantum mechanics the deterministic property of classical physics is an emergent phenomenon appropriate only on macroscopic scales. Lee and Wick introduced Lorentz invariant quantum theories where causality is an emergent phenomenon appropriate for macroscopic time scales. In this paper we analyze a Lee-Wick version of the O(N) model. We argue that in the large-N limit this theory has a unitary and Lorentz invariant S matrix and is therefore free of paradoxes in scattering experiments. We discuss some of its acausal properties.

Modeling the acid-base properties of bacterial surfaces: A combined spectroscopic and potentiometric study of the gram-positive bacterium Bacillus subtilis.

PubMed

Leone, Laura; Ferri, Diego; Manfredi, Carla; Persson, Per; Shchukarev, Andrei; Sjöberg, Staffan; Loring, John

2007-09-15

In this study, macroscopic and spectroscopic data were combined to develop a surface complexation model that describes the acid-base properties of Bacillus subtilis. The bacteria were freeze-dried and then resuspended in 0.1 M NaCl ionic medium. Macroscopic measurements included potentiometric acid-base titrations and electrophoretic mobility measurements. In addition, ATR-FTIR spectra of wet pastes from suspensions of Bacillus subtilis at different pH values were collected. The least-squares program MAGPIE was used to generate a surface complexation model that takes into account the presence of three acid-base sites on the surface: tripple bond COOH, tripple bond NH+, and tripple bond PO-, which were identified previously by XPS measurements. Both potentiometric titration data and ATR-FTIR spectra were used quantitatively, and electrostatic effects at the charged bacterial surface were accounted for using the constant capacitance model. The model was calculated using two different approaches: in the first one XPS data were used to constrain the ratio of the total concentrations of all three surface sites. The capacitance of the double layer, the total buffer capacity, and the deprotonation constants of the tripple bond NH+, tripple bond POH, and tripple bond COOH species were determined in the fit. A second approach is presented in which the ratio determined by XPS of the total concentrations of tripple bond NH+ to tripple bond PO- sites is relaxed. The total concentration of tripple bond PO- sites was determined in the fit, while the deprotonation constant for tripple bond POH was manually varied until the minimization led to a model which predicted an isoelectric point that resulted in consistency with electrophoretic mobility data. The model explains well the buffering capacity of Bacillus subtilis suspensions in a wide pH range (between pH=3 and pH=9) which is of considerable environmental interest. In particular, a similar quantitative use of the IR data opens up possibilities to model other bacterial surfaces at the laboratory scale and help estimate the buffering capacity of carboxylate-containing compounds in natural samples.

Quantum theory and human perception of the macro-world

PubMed Central

Aerts, Diederik

2014-01-01

We investigate the question of ‘why customary macroscopic entities appear to us humans as they do, i.e., as bounded entities occupying space and persisting through time’, starting from our knowledge of quantum theory, how it affects the behavior of such customary macroscopic entities, and how it influences our perception of them. For this purpose, we approach the question from three perspectives. Firstly, we look at the situation from the standard quantum angle, more specifically the de Broglie wavelength analysis of the behavior of macroscopic entities, indicate how a problem with spin and identity arises, and illustrate how both play a fundamental role in well-established experimental quantum-macroscopical phenomena, such as Bose-Einstein condensates. Secondly, we analyze how the question is influenced by our result in axiomatic quantum theory, which proves that standard quantum theory is structurally incapable of describing separated entities. Thirdly, we put forward our new ‘conceptual quantum interpretation’, including a highly detailed reformulation of the question to confront the new insights and views that arise with the foregoing analysis. At the end of the final section, a nuanced answer is given that can be summarized as follows. The specific and very classical perception of human seeing—light as a geometric theory—and human touching—only ruled by Pauli's exclusion principle—plays a role in our perception of macroscopic entities as ontologically stable entities in space. To ascertain quantum behavior in such macroscopic entities, we will need measuring apparatuses capable of its detection. Future experimental research will have to show if sharp quantum effects—as they occur in smaller entities—appear to be ontological aspects of customary macroscopic entities. It remains a possibility that standard quantum theory is an incomplete theory, and hence incapable of coping ultimately with separated entities, meaning that a more general theory will be needed. PMID:25009510

Electromagnetic fields and their impacts

NASA Astrophysics Data System (ADS)

Prša, M. A.; Kasaš-Lažetić, K. K.

2018-01-01

The main goal of this paper is to briefly recall some different electromagnetic field definitions, some macroscopic sources of electromagnetic fields, electromagnetic fields classification regarding time dependences, and the ways of field determination in concrete cases. After that, all the mechanisms of interaction between electromagnetic field and substance, on atomic level, are described in details. Interaction between substance and electric field is investigated separately from the substance and magnetic field interaction. It is demonstrated that, in all cases of the unique electromagnetic field, total interaction can be treated as a superposition of two separated interactions. Finally, the main electromagnetic fields surrounding us is cited and discussed.

Classic tongue lipoma: a common tumour at a rare site

PubMed Central

Magadum, Dilip; Sanadi, Appasab; Agrawal, Jiwanasha Manish; Agrawal, Manish Suresh

2013-01-01

Lipoma is the commonest benign tumour occurring at any anatomical site where fat is present, but occurrence in the oral cavity is rare. Tongue which is totally devoid of fat cells is a rare site for lipoma. This is one such rare case of the universal tumour, presenting at the lateral margin of the tongue, for which complete tumour excision was done. Macroscopically the mass had a hard consistency and measured 3.0×2.0 cm. From microscopic examination, diagnosis of lipoma was made. Recurrence of tongue lipoma is rare. PMID:23370950

Successful operative treatment of uterine leiomyoma with extensive intravenous extension to the IVC, right heart, and pulmonary arteries.

PubMed

Brar, Ranjeet; Skervin, Alicia; El-Sakka, Karim; Fish, Andrew; Lewis, Michael

2018-01-17

Intravenous extension of benign uterine leiomyomata ('fibroids'), in the absence of discrete metastatic disease has rarely been reported. 'Fibroids' remain one of the most common premenopausal uterine pathologies. We report the diagnosis and multidisciplinary led operative management of a 52-year-old woman with a histologically benign, but biologically aggressive, uterine leiomyoma with intravenous extension to the inferior vena cava (IVC), right heart and pulmonary arteries. Total abdominal hysterectomy and bilateral salpingo-oophorectomy combined with exploration of the sub-hepatic IVC and heart under deep hypothermic circulatory arrest achieved its successful macroscopic clearance.

Continuous Feedback and Macroscopic Coherence

NASA Technical Reports Server (NTRS)

Tombesi, Paolo; Vitali, David

1996-01-01

We show that a model, recently introduced for quantum nondemolition measurements of a quantum observable, can be adapted to obtain a measurement scheme which is able to slow down the destruction of macroscopic coherence due to the measurement apparatus.

Nonequilibrium electromagnetics: Local and macroscopic fields and constitutive relationships

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker-Jarvis, James; Kabos, Pavel; Holloway, Christopher L.

We study the electrodynamics of materials using a Liouville-Hamiltonian-based statistical-mechanical theory. Our goal is to develop electrodynamics from an ensemble-average viewpoint that is valid for microscopic and nonequilibrium systems at molecular to submolecular scales. This approach is not based on a Taylor series expansion of the charge density to obtain the multipoles. Instead, expressions of the molecular multipoles are used in an inverse problem to obtain the averaging statistical-density function that is used to obtain the macroscopic fields. The advantages of this method are that the averaging function is constructed in a self-consistent manner and the molecules can either bemore » treated as point multipoles or contain more microstructure. Expressions for the local and macroscopic fields are obtained, and evolution equations for the constitutive parameters are developed. We derive equations for the local field as functions of the applied, polarization, magnetization, strain density, and macroscopic fields.« less

Fission properties of Po isotopes in different macroscopic-microscopic models

NASA Astrophysics Data System (ADS)

Bartel, J.; Pomorski, K.; Nerlo-Pomorska, B.; Schmitt, Ch

2015-11-01

Fission-barrier heights of nuclei in the Po isotopic chain are investigated in several macroscopic-microscopic models. Using the Yukawa-folded single-particle potential, the Lublin-Strasbourg drop (LSD) model, the Strutinsky shell-correction method to yield the shell corrections and the BCS theory for the pairing contributions, fission-barrier heights are calculated and found in quite good agreement with the experimental data. This turns out, however, to be only the case when the underlying macroscopic, liquid-drop (LD) type, theory is well chosen. Together with the LSD approach, different LD parametrizations proposed by Moretto et al are tested. Four deformation parameters describing respectively elongation, neck-formation, reflectional-asymmetric, and non-axiality of the nuclear shape thus defining the so called modified Funny Hills shape parametrization are used in the calculation. The present study clearly demonstrates that nuclear fission-barrier heights constitute a challenging and selective tool to discern between such different macroscopic approaches.

Equation-free multiscale computation: algorithms and applications.

PubMed

Kevrekidis, Ioannis G; Samaey, Giovanni

2009-01-01

In traditional physicochemical modeling, one derives evolution equations at the (macroscopic, coarse) scale of interest; these are used to perform a variety of tasks (simulation, bifurcation analysis, optimization) using an arsenal of analytical and numerical techniques. For many complex systems, however, although one observes evolution at a macroscopic scale of interest, accurate models are only given at a more detailed (fine-scale, microscopic) level of description (e.g., lattice Boltzmann, kinetic Monte Carlo, molecular dynamics). Here, we review a framework for computer-aided multiscale analysis, which enables macroscopic computational tasks (over extended spatiotemporal scales) using only appropriately initialized microscopic simulation on short time and length scales. The methodology bypasses the derivation of macroscopic evolution equations when these equations conceptually exist but are not available in closed form-hence the term equation-free. We selectively discuss basic algorithms and underlying principles and illustrate the approach through representative applications. We also discuss potential difficulties and outline areas for future research.

Graphene chiral liquid crystals and macroscopic assembled fibres

PubMed Central

Xu, Zhen; Gao, Chao

2011-01-01

Chirality and liquid crystals are both widely expressed in nature and biology. Helical assembly of mesophasic molecules and colloids may produce intriguing chiral liquid crystals. To date, chiral liquid crystals of 2D colloids have not been explored. As a typical 2D colloid, graphene is now receiving unprecedented attention. However, making macroscopic graphene fibres is hindered by the poor dispersibility of graphene and by the lack of an assembly method. Here we report that soluble, chemically oxidized graphene or graphene oxide sheets can form chiral liquid crystals in a twist-grain-boundary phase-like model with simultaneous lamellar ordering and long-range helical frustrations. Aqueous graphene oxide liquid crystals were continuously spun into metres of macroscopic graphene oxide fibres; subsequent chemical reduction gave the first macroscopic neat graphene fibres with high conductivity and good mechanical performance. The flexible, strong graphene fibres were knitted into designed patterns and into directionally conductive textiles. PMID:22146390

Hybrid methods for witnessing entanglement in a microscopic-macroscopic system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spagnolo, Nicolo; Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia, Piazzale Aldo Moro 5, I-00185 Roma; Vitelli, Chiara

2011-09-15

We propose a hybrid approach to the experimental assessment of the genuine quantum features of a general system consisting of microscopic and macroscopic parts. We infer entanglement by combining dichotomic measurements on a bidimensional system and phase-space inference through the Wigner distribution associated with the macroscopic component of the state. As a benchmark, we investigate the feasibility of our proposal in a bipartite-entangled state composed of a single-photon and a multiphoton field. Our analysis shows that, under ideal conditions, maximal violation of a Clauser-Horne-Shimony-Holt-based inequality is achievable regardless of the number of photons in the macroscopic part of the state.more » The difficulty in observing entanglement when losses and detection inefficiency are included can be overcome by using a hybrid entanglement witness that allows efficient correction for losses in the few-photon regime.« less

Microscopic and macroscopic instabilities in finitely strained porous elastomers

NASA Astrophysics Data System (ADS)

Michel, J. C.; Lopez-Pamies, O.; Ponte Castañeda, P.; Triantafyllidis, N.

2007-05-01

The present work is an in-depth study of the connections between microstructural instabilities and their macroscopic manifestations—as captured through the effective properties—in finitely strained porous elastomers. The powerful second-order homogenization (SOH) technique initially developed for random media, is used for the first time here to study the onset of failure in periodic porous elastomers and the results are compared to more accurate finite element method (FEM) calculations. The influence of different microgeometries (random and periodic), initial porosity, matrix constitutive law and macroscopic load orientation on the microscopic buckling (for periodic microgeometries) and macroscopic loss of ellipticity (for all microgeometries) is investigated in detail. In addition to the above-described stability-based onset-of-failure mechanisms, constraints on the principal solution are also addressed, thus giving a complete picture of the different possible failure mechanisms present in finitely strained porous elastomers.

Total cross section of furfural by electron impact: Experiment and theory.

PubMed

Traoré Dubuis, A; Verkhovtsev, A; Ellis-Gibbings, L; Krupa, K; Blanco, F; Jones, D B; Brunger, M J; García, G

2017-08-07

We present experimental total cross sections for electron scattering from furfural in the energy range from 10 to 1000 eV, as measured using a double electrostatic analyzer gas cell electron transmission experiment. These results are compared to theoretical data for furfural, as well as to experimental and theoretical values for the structurally similar molecules furan and tetrahydrofuran. The measured total cross section is in agreement with the theoretical results obtained by means of the independent-atom model with screening corrected additivity rule including interference method. In the region of higher electron energies, from 500 eV to 10 keV, the total electron scattering cross section is also estimated using a semi-empirical model based on the number of electrons and dipole polarizabilities of the molecular targets. Together with the recently measured differential and integral cross sections, and the furfural energy-loss spectra, the present total cross section data nearly complete the data set that is required for numerical simulation of low-energy electron processes in furfural, covering the range of projectile energies from a few electron volts up to 10 keV.

Total cross section of furfural by electron impact: Experiment and theory

NASA Astrophysics Data System (ADS)

Traoré Dubuis, A.; Verkhovtsev, A.; Ellis-Gibbings, L.; Krupa, K.; Blanco, F.; Jones, D. B.; Brunger, M. J.; García, G.

2017-08-01

We present experimental total cross sections for electron scattering from furfural in the energy range from 10 to 1000 eV, as measured using a double electrostatic analyzer gas cell electron transmission experiment. These results are compared to theoretical data for furfural, as well as to experimental and theoretical values for the structurally similar molecules furan and tetrahydrofuran. The measured total cross section is in agreement with the theoretical results obtained by means of the independent-atom model with screening corrected additivity rule including interference method. In the region of higher electron energies, from 500 eV to 10 keV, the total electron scattering cross section is also estimated using a semi-empirical model based on the number of electrons and dipole polarizabilities of the molecular targets. Together with the recently measured differential and integral cross sections, and the furfural energy-loss spectra, the present total cross section data nearly complete the data set that is required for numerical simulation of low-energy electron processes in furfural, covering the range of projectile energies from a few electron volts up to 10 keV.

Bridging macroscopic and microscopic methods for the measurements of cerebral blood flow: Toward finding the determinants in maintaining the CBF homeostasis.

PubMed

Kanno, I; Masamoto, K

Methods exist to evaluate the cerebral blood flow (CBF) at both the macroscopic and microscopic spatial scales. These methods provide complementary information for understanding the mechanism in maintaining an adequate blood supply in response to neural demand. The macroscopic CBF assesses perfusion flow, which is usually measured using radioactive tracers, such as diffusible, nondiffusible, or microsphere. Each of them determines CBF based on indicator dilution principle or particle fraction principle under the assumption that CBF is steady state during the measurement. Macroscopic CBF therefore represents averaged CBF over a certain space and time domains. On the other hand, the microscopic CBF assesses bulk flow, usually measures using real-time microscopy. The method assesses hemodynamics of microvessels, ie, vascular dimensions and flow velocities of fluorescently labeled or nonlabeled RBC and plasma markers. The microscopic CBF continuously fluctuates in time and space. Smoothing out this heterogeneity may lead to underestimation in the macroscopic CBF. To link the two measurements, it is needed to introduce a common parameter which is measurable for the both methods, such as mean transit time. Additionally, applying the defined physiological and/or pharmacological perturbation may provide a good exercise to determine how the specific perturbations interfere the quantitative relationships between the macroscopic and microscopic CBF. Finally, bridging these two-scale methods potentially gives a further indication how the absolute CBF is regulated with respect to a specific type of the cerebrovascular tones or capillary flow velocities in the brain. © 2016 Elsevier B.V. All rights reserved.

[Macroscopic haematuria after transurethral resection of the prostate].

PubMed

Normand, Guillaume; Guignet, Julien; Briffaux, Raphaël; Merlet, Benoît; Irani, Jacques; Doré, Bertrand

2006-09-01

Although macroscopic haematuria during the month following transurethral resection of the prostate, due to sloughing of necrotic tissue, is a phenomenon well known to urologists since introduction of endoscopic resection, its pathophysiological and epidemiological characteristics are poorly defined. The objective of this retrospective study was to define the incidence of serious macroscopic haematuria after transurethral resection of the prostate (TURP) and to identify the risk factors for macroscopic haematuria. The hospital database was used to identify patients treated by TURP between 1997 and 2004 and rehospitalized during the 31 days following the procedure. Files of patients presenting with haematuria and bladder clots were selected and analysed. Ten of a series of 624 patients undergoing TURP were hospitalised for bladder clots and their case files were analysed: median age: 72 years, median duration of TURP: 45 min and median weight of resection: 12 g. The operators' experience and the duration of post-TURP catheterization were not informative. In 2 cases, prostate cancer was diagnosed after analysis of resection chips. Two patients were treated by anticoagulants. Patients were essentially rehospitalized during the 2nd week (median: 11th day). A bladder catheter for was inserted for lavage in each case. No patient required reoperation or removal of clots under general anaesthesia. Two patients were transfused. We did not identify any risk factor for sloughing leading to macroscopic haematuria during the month following TURP. Macroscopic haematuria justifying rehospitalization is a rare event. However, in view of this low incidence, optimal analysis could only be performed in the context of a national prospective register.

Controllable synthesis of mesoporous carbon nanospheres and Fe-N/carbon nanospheres as efficient oxygen reduction electrocatalysts

NASA Astrophysics Data System (ADS)

Wei, Jing; Liang, Yan; Zhang, Xinyi; Simon, George P.; Zhao, Dongyuan; Zhang, Jin; Jiang, Sanping; Wang, Huanting

2015-03-01

The synthesis of mesoporous carbon nanospheres (MCNs), especially with diameters below 200 nm remains a great challenge due to weak interactions between the carbon precursors and soft templates, as well as the uncontrollable cross-linking rate of carbon precursors. Herein, we demonstrate a simple acid-assisted, hydrothermal synthesis approach to synthesizing such uniform MCNs with well controlled diameters ranging from 20 to 150 nm under highly acidic conditions (2 M HCl). Both the carbon precursor and the template are partly protonated under such conditions and show additional Coulombic interactions with chloride ions (acts as mediators). This kind of enhanced interaction is similar to that of the ``I+X-S+'' mechanism in the synthesis of mesoporous metal oxide, which can effectively retard the cross-linking rate of resol molecules and avoid macroscopic phase separation during the hydrothermal synthesis. Due to their uniform spherical morphology, small diameter, and high surface areas, MCNs can be modified with Fe and N species via impregnation of cheap precursors (ferric nitrate and dicyandiamide), which are further converted into nonprecious electrocatalysts for oxygen reduction reactions. The resulting Fe-N/MCNs exhibit high catalytic activities, long-term stability and improved methanol tolerance under alkaline conditions, which can be potentially used in direct methanol fuel cells and metal-air batteries.The synthesis of mesoporous carbon nanospheres (MCNs), especially with diameters below 200 nm remains a great challenge due to weak interactions between the carbon precursors and soft templates, as well as the uncontrollable cross-linking rate of carbon precursors. Herein, we demonstrate a simple acid-assisted, hydrothermal synthesis approach to synthesizing such uniform MCNs with well controlled diameters ranging from 20 to 150 nm under highly acidic conditions (2 M HCl). Both the carbon precursor and the template are partly protonated under such conditions and show additional Coulombic interactions with chloride ions (acts as mediators). This kind of enhanced interaction is similar to that of the ``I+X-S+'' mechanism in the synthesis of mesoporous metal oxide, which can effectively retard the cross-linking rate of resol molecules and avoid macroscopic phase separation during the hydrothermal synthesis. Due to their uniform spherical morphology, small diameter, and high surface areas, MCNs can be modified with Fe and N species via impregnation of cheap precursors (ferric nitrate and dicyandiamide), which are further converted into nonprecious electrocatalysts for oxygen reduction reactions. The resulting Fe-N/MCNs exhibit high catalytic activities, long-term stability and improved methanol tolerance under alkaline conditions, which can be potentially used in direct methanol fuel cells and metal-air batteries. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr00331h

Photoeffect cross sections of several rare-earth elements for 323-keV photons

NASA Astrophysics Data System (ADS)

Umesh, T. K.; Anasuya, S. J.; Shylaja Kumari, J.; Gowda, Channe; Gopinathan Nair, K. P.; Gowda, Ramakrishna

1992-02-01

Total-attenuation cross sections of the oxides of rare-earth elements such as La, Ce, Pr, Nd, Sm, Gd, Dy, Ho, and Er, and also NaNO3 and NaNO2 have been measured in a narrow-beam geometry setup at 323 keV. The total-attenuation cross section for oxygen was obtained as the difference in NaNO3 and NaNO2 cross sections. Using this, the total-attenuation cross sections of the individual lanthanides have been obtained with the aid of the mixture rule. From these, the photoeffect cross sections were derived by subtracting the scattering contribution. These values are found to agree well with Scofield's theoretical data [University of California Report No. UCRL 51326, 1973 (unpublished)].

Fluctuation-enhanced electric conductivity in electrolyte solutions

DOE PAGES

Péraud, Jean-Philippe; Nonaka, Andrew J.; Bell, John B.; ...

2017-09-26

In this work, we analyze the effects of an externally applied electric field on thermal fluctuations for a binary electrolyte fluid. We show that the fluctuating Poisson–Nernst–Planck (PNP) equations for charged multispecies diffusion coupled with the fluctuating fluid momentum equation result in enhanced charge transport via a mechanism distinct from the well-known enhancement of mass transport that accompanies giant fluctuations. Although the mass and charge transport occurs by advection by thermal velocity fluctuations, it can macroscopically be represented as electrodiffusion with renormalized electric conductivity and a nonzero cation–anion diffusion coefficient. Specifically, we predict a nonzero cation–anion Maxwell– Stefan coefficient proportionalmore » to the square root of the salt concentration, a prediction that agrees quantitatively with experimental measurements. The renormalized or effective macroscopic equations are different from the starting PNP equations, which contain no cross-diffusion terms, even for rather dilute binary electrolytes. At the same time, for infinitely dilute solutions the renormalized electric conductivity and renormalized diffusion coefficients are consistent and the classical PNP equations with renormalized coefficients are recovered, demonstrating the self-consistency of the fluctuating hydrodynamics equations. Our calculations show that the fluctuating hydrodynamics approach recovers the electrophoretic and relaxation corrections obtained by Debye–Huckel–Onsager theory, while elucidating the physical origins of these corrections and generalizing straightforwardly to more complex multispecies electrolytes. Lastly, we show that strong applied electric fields result in anisotropically enhanced “giant” velocity fluctuations and reduced fluctuations of salt concentration.« less

Effect of calcium/sodium ion exchange on the osmotic properties and structure of polyelectrolyte gels.

PubMed

Horkay, Ferenc; Basser, Peter J; Hecht, Anne-Marie; Geissler, Erik

2015-12-01

We discuss the main findings of a long-term research program exploring the consequences of sodium/calcium ion exchange on the macroscopic osmotic and elastic properties, and the microscopic structure of representative synthetic polyelectrolyte (sodium polyacrylate, (polyacrylic acid)) and biopolymer gels (DNA). A common feature of these gels is that above a threshold calcium ion concentration, they exhibit a reversible volume phase transition. At the macroscopic level, the concentration dependence of the osmotic pressure shows that calcium ions influence primarily the third-order interaction term in the Flory-Huggins model of polymer solutions. Mechanical tests reveal that the elastic modulus is practically unaffected by the presence of calcium ions, indicating that ion bridging does not create permanent cross-links. At the microscopic level, small-angle neutron scattering shows that polyacrylic acid and DNA gels exhibit qualitatively similar structural features in spite of important differences (e.g. chain flexibility and chemical composition) between the two polymers. The main effect of calcium ions is that the neutron scattering intensity increases due to the decrease in the osmotic modulus. At the level of the counterion cloud around dissolved macroions, anomalous small-angle X-ray scattering measurements made on DNA indicate that divalent ions form a cylindrical sheath enveloping the chain, but they are not localized. Small-angle neutron scattering and small-angle X-ray scattering provide complementary information on the structure and interactions in polymer solutions and gels. © IMechE 2015.

Fluctuation-enhanced electric conductivity in electrolyte solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Péraud, Jean-Philippe; Nonaka, Andrew J.; Bell, John B.

In this work, we analyze the effects of an externally applied electric field on thermal fluctuations for a binary electrolyte fluid. We show that the fluctuating Poisson–Nernst–Planck (PNP) equations for charged multispecies diffusion coupled with the fluctuating fluid momentum equation result in enhanced charge transport via a mechanism distinct from the well-known enhancement of mass transport that accompanies giant fluctuations. Although the mass and charge transport occurs by advection by thermal velocity fluctuations, it can macroscopically be represented as electrodiffusion with renormalized electric conductivity and a nonzero cation–anion diffusion coefficient. Specifically, we predict a nonzero cation–anion Maxwell– Stefan coefficient proportionalmore » to the square root of the salt concentration, a prediction that agrees quantitatively with experimental measurements. The renormalized or effective macroscopic equations are different from the starting PNP equations, which contain no cross-diffusion terms, even for rather dilute binary electrolytes. At the same time, for infinitely dilute solutions the renormalized electric conductivity and renormalized diffusion coefficients are consistent and the classical PNP equations with renormalized coefficients are recovered, demonstrating the self-consistency of the fluctuating hydrodynamics equations. Our calculations show that the fluctuating hydrodynamics approach recovers the electrophoretic and relaxation corrections obtained by Debye–Huckel–Onsager theory, while elucidating the physical origins of these corrections and generalizing straightforwardly to more complex multispecies electrolytes. Lastly, we show that strong applied electric fields result in anisotropically enhanced “giant” velocity fluctuations and reduced fluctuations of salt concentration.« less

``Illuminating'' electron diffusion regions of collisionless magnetic reconnection using electron agyrotropy

NASA Astrophysics Data System (ADS)

Scudder, Jack; Daughton, William

2008-06-01

Agyrotropy is a scalar measure of the departure of the pressure tensor from cylindrical symmetry about the local magnetic field direction. Ordinarily electrons are well modeled as gyrotropic with very small agyrotropy. Intensified layers of electron agyrotropy are demonstrated to highlight the thin electron gyroradius scale boundary regions adjoining separatrices, X and O lines of full particle simulations of collisionless magnetic reconnection. Examples are presented to show these effects in antiparallel and guide field geometries, pair plasmas, and simulations at a variety of mass ratios, including a hydrogen plasma. Agyrotropy has been determined from the PIC pressure tensor using a new, fast algorithm developed to correct discreteness contributions to the apparent agyrotropy. As a local scalar diagnostic, agyrotropy is shown to be potentially useful with single spacecraft data to identify the crossing or proximity of electron scale current layers, thus providing a kinetic level diagnosis of a given layer's ability to be a possible site of the collisionless reconnection process. Such kinetic tools are certainly complimentary to the other macroscopic signatures of reconnection. Because of the extreme circumstances required for electron agyrotropy, detection of these signatures with framing macroscopic signatures might prove useful for the discovery of new reconnection sites in nature and 3-D codes of collisionless reconnection. The agyrotropy in the 2-D PIC codes reflect long-lived bulges on the distribution function that appear to be organized by the direction and size of slowly evolving perpendicular electric fields in these layers and are not consistent with gyrophase bunching.

Multiscale Aspects of Generation of High-Gamma Activity during Seizures in Human Neocortex123

PubMed Central

Marcuccilli, Charles J.; Ben-Mabrouk, Faiza; Lew, Sean M.; Goodman, Robert R.; McKhann, Guy M.; Frim, David M.; Kohrman, Michael H.; Schevon, Catherine A.; van Drongelen, Wim

2016-01-01

High-gamma (HG; 80-150 Hz) activity in macroscopic clinical records is considered a marker for critical brain regions involved in seizure initiation; it is correlated with pathological multiunit firing during neocortical seizures in the seizure core, an area identified by correlated multiunit spiking and low frequency seizure activity. However, the effects of the spatiotemporal dynamics of seizure on HG power generation are not well understood. Here, we studied HG generation and propagation, using a three-step, multiscale signal analysis and modeling approach. First, we analyzed concurrent neuronal and microscopic network HG activity in neocortical slices from seven intractable epilepsy patients. We found HG activity in these networks, especially when neurons displayed paroxysmal depolarization shifts and network activity was highly synchronized. Second, we examined HG activity acquired with microelectrode arrays recorded during human seizures (n = 8). We confirmed the presence of synchronized HG power across microelectrode records and the macroscale, both specifically associated with the core region of the seizure. Third, we used volume conduction-based modeling to relate HG activity and network synchrony at different network scales. We showed that local HG oscillations require high levels of synchrony to cross scales, and that this requirement is met at the microscopic scale, but not within macroscopic networks. Instead, we present evidence that HG power at the macroscale may result from harmonics of ongoing seizure activity. Ictal HG power marks the seizure core, but the generating mechanism can differ across spatial scales. PMID:27257623

An Efficient Implementation of the GMC Micromechanics Model for Multi-Phased Materials with Complex Microstructures

NASA Technical Reports Server (NTRS)

Pindera, Marek-Jerzy; Bednarcyk, Brett A.

1997-01-01

An efficient implementation of the generalized method of cells micromechanics model is presented that allows analysis of periodic unidirectional composites characterized by repeating unit cells containing thousands of subcells. The original formulation, given in terms of Hill's strain concentration matrices that relate average subcell strains to the macroscopic strains, is reformulated in terms of the interfacial subcell tractions as the basic unknowns. This is accomplished by expressing the displacement continuity equations in terms of the stresses and then imposing the traction continuity conditions directly. The result is a mixed formulation wherein the unknown interfacial subcell traction components are related to the macroscopic strain components. Because the stress field throughout the repeating unit cell is piece-wise uniform, the imposition of traction continuity conditions directly in the displacement continuity equations, expressed in terms of stresses, substantially reduces the number of unknown subcell traction (and stress) components, and thus the size of the system of equations that must be solved. Further reduction in the size of the system of continuity equations is obtained by separating the normal and shear traction equations in those instances where the individual subcells are, at most, orthotropic. The reformulated version facilitates detailed analysis of the impact of the fiber cross-section geometry and arrangement on the response of multi-phased unidirectional composites with and without evolving damage. Comparison of execution times obtained with the original and reformulated versions of the generalized method of cells demonstrates the new version's efficiency.

Two level approach to safety planning incorporating the Highway Safety Manual (HSM) network screening.

DOT National Transportation Integrated Search

2014-04-01

Compared to microscopic safety studies, macroscopic-focused research is more efficient at integrating zonal-level features into crash prediction models and identifying hot zones. However, macroscopic screening has accuracy limitations. Thus, this stu...

Calibration of steady-state car-following models using macroscopic loop detector data.

DOT National Transportation Integrated Search

2010-05-01

The paper develops procedures for calibrating the steady-state component of various car following models using : macroscopic loop detector data. The calibration procedures are developed for a number of commercially available : microscopic traffic sim...

Target correlation effects on neutron-nucleus total, absorption, and abrasion cross sections

NASA Technical Reports Server (NTRS)

Cucinotta, Francis A.; Townsend, Lawrence W.; Wilson, John W.

1991-01-01

Second order optical model solutions to the elastic scattering amplitude were used to evaluate total, absorption, and abrasion cross sections for neutron nucleus scattering. Improved agreement with experimental data for total and absorption cross sections is found when compared with first order (coherent approximation) solutions, especially below several hundred MeV. At higher energies, the first and second order solutions are similar. There are also large differences in abrasion cross section calculations; these differences indicate a crucial role for cluster knockout in the abrasion step.

Divergence of the total cross section for three body rearrangement collisions with coulomb interactions

NASA Technical Reports Server (NTRS)

Omidvar, K.

1972-01-01

Three charged particles 1, 2, 3 collide according to the reaction 1+(2+3) yields (1+3)+2, where (2+3) and (1+3) are hydrogenlike bound states. It is shown when (1+3) is in a highly excited state n, due to the repulsive potential, the cross section in the first Born approximation behaves as 1/n which makes the total cross section to diverge like ln n. The total cross sections in the higher orders of the Born approximation are similarly divergent logarithmically.

Partial Photoneutron Cross Sections for 207,208Pb

NASA Astrophysics Data System (ADS)

Kondo, T.; Utsunomiya, H.; Goriely, S.; Iwamoto, C.; Akimune, H.; Yamagata, T.; Toyokawa, H.; Harada, H.; Kitatani, F.; Lui, Y.-W.; Hilaire, S.; Koning, A. J.

2014-05-01

Using linearly-polarized laser-Compton scattering γ-rays, partial E1 and M1 photoneutron cross sections along with total cross sections were determined for 207,208Pb at four energies near neutron threshold by measuring anisotropies in photoneutron emission. Separately, total photoneutron cross sections were measured for 207,208Pb with a high-efficiency 4π neutron detector. The partial cross section measurement provides direct evidence for the presence of pygmy dipole resonance (PDR) in 207,208Pb in the vicinity of neutron threshold. The strength of PDR amounts to 0.32%-0.42% of the Thomas-Reiche-Kuhn sum rule. Several μN2 units of B(M1)↑ strength were observed in 207,208Pb just above neutron threshold, which correspond to M1 cross sections less than 10% of the total photoneutron cross sections.

Evaluation of Morphological Plasticity in the Cerebella of Basketball Players with MRI

PubMed Central

Park, In Sung; Han, Jong Woo; Lee, Kea Joo; Lee, Nam Joon; Lee, Won Teak; Park, Kyung Ah

2006-01-01

Cerebellum is a key structure involved in motor learning and coordination. In animal models, motor skill learning increased the volume of molecular layer and the number of synapses on Purkinje cells in the cerebellar cortex. The aim of this study is to investigate whether the analogous change of cerebellar volume occurs in human population who learn specialized motor skills and practice them intensively for a long time. Magnetic resonance image (MRI)-based cerebellar volumetry was performed in basketball players and matched controls with V-works image software. Total brain volume, absolute and relative cerebellar volumes were compared between two groups. There was no significant group difference in the total brain volume, the absolute and the relative cerebellar volume. Thus we could not detect structural change in the cerebellum of this athlete group in the macroscopic level. PMID:16614526

The triaxiality and Coriolis effects on the fission barrier in isovolumic nuclei with mass number A = 256 based on multidimensional total Routhian surface calculations

NASA Astrophysics Data System (ADS)

Chai, Qing-Zhen; Zhao, Wei-Juan; Wang, Hua-Lei; Liu, Min-Liang; Xu, Fu-Rong

2018-05-01

The triaxiality and Coriolis effects on the first fission barrier in even-even nuclei with A=256 have been studied in terms of the approach of multidimensional total Routhian surface calculations. The present results are compared with available data and other theories, showing a good agreement. Based on the deformation energy or Routhian curves, the first fission barriers are analyzed, focusing on their shapes, heights, and evolution with rotation. It is found that, relative to the effect on the ground-state minimum, the saddle point, at least the first one, can be strongly affected by the triaxial deformation degree of freedom and Coriolis force. The evolution trends of the macroscopic and microscopic (shell and pairing) contributions as well as the triaxial fission barriers are briefly discussed.

Calculations of Total Classical Cross Sections for a Central Field

NASA Astrophysics Data System (ADS)

Tsyganov, D. L.

2018-07-01

In order to find the total collision cross-section a direct method of the effective potential (EPM) in the framework of classical mechanics was proposed. EPM allows to over come both the direct scattering problem (calculation of the total collision cross-section) and the inverse scattering problem (reconstruction of the scattering potential) quickly and effectively. A general analytical expression was proposed for the generalized Lennard-Jones potentials: (6-3), (9-3), (12-3), (6-4), (8-4), (12-4), (8-6), (12-6), (18-6). The values for the scattering potential of the total cross section for pairs such as electron-N2, N-N, and O-O2 were obtained in a good approximation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dupertuis, M.A.; Proctor, M.; Acklin, B.

Energy balance and reciprocity relations are studied for harmonic inhomogeneous plane waves that are incident upon a stack of continuous absorbing dielectric media that are macroscopically characterized by their electric and magnetic permittivities and their conductivities. New cross terms between parallel electric and parallel magnetic modes are identified in the fully generalized Poynting vector. The symmetry and the relations between the general Fresnel coefficients are investigated in the context of energy balance at the interface. The contributions of the so-called mixed Poynting vector are discussed in detail. In particular a new transfer matrix is introduced for energy fluxes in thin-filmmore » optics based on the Poynting and mixed Poynting vectors. Finally, the study of reciprocity relations leads to a generalization of a theorem of reversibility for conducting and dielectric media. 16 refs.« less

Shielding properties of 80TeO2-5TiO2-(15-x) WO3-xAnOm glasses using WinXCom and MCNP5 code

NASA Astrophysics Data System (ADS)

Dong, M. G.; El-Mallawany, R.; Sayyed, M. I.; Tekin, H. O.

2017-12-01

Gamma ray shielding properties of 80TeO2-5TiO2-(15-x) WO3-xAnOm glasses, where AnOm is Nb2O5 = 0.01, 5, Nd2O3 = 3, 5 and Er2O3 = 5 mol% have been achieved. Shielding parameters; mass attenuation coefficients, half value layers, and macroscopic effective removal cross section for fast neutrons have been computed by using WinXCom program and MCNP5 Monte Carlo code. In addition, by using Geometric Progression method (G-P), exposure buildup factor values were also calculated. Variations of shielding parameters are discussed for the effect of REO addition into the glasses and photon energy.

Molecular and Kinetic Models for High-rate Thermal Degradation of Polyethylene

DOE PAGES

Lane, J. Matthew; Moore, Nathan W.

2018-02-01

Thermal degradation of polyethylene is studied under the extremely high rate temperature ramps expected in laser-driven and X-ray ablation experiments—from 10 10 to 10 14 K/s in isochoric, condensed phases. The molecular evolution and macroscopic state variables are extracted as a function of density from reactive molecular dynamics simulations using the ReaxFF potential. The enthalpy, dissociation onset temperature, bond evolution, and observed cross-linking are shown to be rate dependent. These results are used to parametrize a kinetic rate model for the decomposition and coalescence of hydrocarbons as a function of temperature, temperature ramp rate, and density. In conclusion, the resultsmore » are contrasted to first-order random-scission macrokinetic models often assumed for pyrolysis of linear polyethylene under ambient conditions.« less

Molecular and Kinetic Models for High-rate Thermal Degradation of Polyethylene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lane, J. Matthew; Moore, Nathan W.

Thermal degradation of polyethylene is studied under the extremely high rate temperature ramps expected in laser-driven and X-ray ablation experiments—from 10 10 to 10 14 K/s in isochoric, condensed phases. The molecular evolution and macroscopic state variables are extracted as a function of density from reactive molecular dynamics simulations using the ReaxFF potential. The enthalpy, dissociation onset temperature, bond evolution, and observed cross-linking are shown to be rate dependent. These results are used to parametrize a kinetic rate model for the decomposition and coalescence of hydrocarbons as a function of temperature, temperature ramp rate, and density. In conclusion, the resultsmore » are contrasted to first-order random-scission macrokinetic models often assumed for pyrolysis of linear polyethylene under ambient conditions.« less

Spontaneous multicentric soft tissue sarcoma in a captive African pygmy hedgehog (Atelerix albiventris): case report and literature review.

PubMed

Díaz-Delgado, Josué; Pool, Roy; Hoppes, Sharman; Cerezo, Argine; Quesada-Canales, Óscar; Stoica, George

2017-05-18

This report describes the clinical, macroscopic, histopathological and immunohistochemical features of a spontaneous multicentric extraskeletal sarcoma in an adult male African hedgehog (Atelerix albiventris). It also provides a succinct up-to-date review on neoplasia in this species. On autopsy examination, main gross findings included a moderately demarcated cranial mass and a multilobulated, caudal intra-abdominal mass. The cranial mass had perforated the underlying temporal and occipital bones and had extended into the cranial vault and was compressing the surface of the cerebellum and cerebrum. Histologic, histochemical and immunohistochemical analyses supported a diagnosis of multicentric poorly differentiated spindle cell sarcoma with fibrosarcomatous, storiform and myxoid foci. The high incidence of neoplasia and cross similarities renders the African hedgehog a suitable species for comparative pathology studies.

Asymptotic Analysis of Time-Dependent Neutron Transport Coupled with Isotopic Depletion and Radioactive Decay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brantley, P S

2006-09-27

We describe an asymptotic analysis of the coupled nonlinear system of equations describing time-dependent three-dimensional monoenergetic neutron transport and isotopic depletion and radioactive decay. The classic asymptotic diffusion scaling of Larsen and Keller [1], along with a consistent small scaling of the terms describing the radioactive decay of isotopes, is applied to this coupled nonlinear system of equations in a medium of specified initial isotopic composition. The analysis demonstrates that to leading order the neutron transport equation limits to the standard time-dependent neutron diffusion equation with macroscopic cross sections whose number densities are determined by the standard system of ordinarymore » differential equations, the so-called Bateman equations, describing the temporal evolution of the nuclide number densities.« less

Totally laparoscopic gallbladder-preserving surgery: A minimally invasive and favorable approach for cholelithiasis.

PubMed

Gao, DE-Kang; Wei, Shao-Hua; Li, Wei; Ren, Jie; Ma, Xiao-Ming; Gu, Chun-Wei; Wu, Hao-Rong

2015-02-01

The aim of the present study was to investigate the effectiveness of laparoscopic gallbladder-preserving surgery (L-GPS) for cholelithiasis and the feasibility and value of totally laparoscopic GPS (TL-GPS). A total of 517 patients underwent L-GPS, including 365 cases of laparoscopy-assisted GPS (LA-GPS), 143 cases of TL-GPS (preservation rate, 98.3%) and nine conversions to laparoscopic cholecystectomy. The surgeries were all performed by one medical team and the mean operating time was 72 min. All macroscopic calculi were removed through endoscopy. The number of calculi observed in the patients was between one and several dozen; diameters ranged between 0.1 and 2.5 cm. Only three cases of incisional infection were noted in the LA-GPS group and long-term follow-up showed a low recurrence rate of 1.2%. L-GPS is, therefore, an excellent approach to cure cholelithiasis and TL-GPS is a feasible and effective option that could avoid incisional complications.

Two level approach to safety planning incorporating the Highway Safety Manual (HSM) network screening : [summary].

DOT National Transportation Integrated Search

2014-04-01

In this project, University of Central Florida researchers combined two types of safety analysis, microscopic and macroscopic, to overcome their limitations. Microscopic models focus on traffic flows and related parameters. Macroscopic models are bas...

Departure of microscopic friction from macroscopic drag in molecular fluid dynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanasaki, Itsuo; Fujiwara, Daiki; Kawano, Satoyuki, E-mail: kawano@me.es.osaka-u.ac.jp

2016-03-07

Friction coefficient of the Langevin equation and drag of spherical macroscopic objects in steady flow at low Reynolds numbers are usually regarded as equivalent. We show that the microscopic friction can be different from the macroscopic drag when the mass is taken into account for particles with comparable scale to the surrounding fluid molecules. We illustrate it numerically by molecular dynamics simulation of chloride ion in water. Friction variation by the atomistic mass effect beyond the Langevin regime can be of use in the drag reduction technology as well as the electro or thermophoresis.

Macroscopic crack formation and extension in pristine and artificially aged PBX 9501

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Cheng; Thompson, Darla G

2010-01-01

A technique has been developed to quantitatively describe macroscopic cracks, both their location and extent, in heterogeneous high explosive and mock materials. By combining such a technique with the deformation field measurement using digital image correlation (DIC), we conduct observation and measurement of the initiation, extension, and coalescence of internal cracks in the compression of Brazilian disk made of pristine and artificially aged PBX 9501 hjgh explosives. Our results conclude quantitatively that aged PBX 9501 is not only weaker but also much more brittle than the pristine one, thus is more susceptible to macroscopic cracking.

OSTEOCHONDROSIS IN THE DISTAL FEMURS OF AN ADULT RETICULATED GIRAFFE (GIRAFFA CAMELOPARDALIS RETICULATA): MACROSCOPIC, RADIOLOGIC, AND HISTOLOGIC FINDINGS.

PubMed

Basu, Christopher; Stoll, Alexander L; Dixon, Jonathon; Molenaar, Fieke Marije; Flach, Edmund; Smith, Ken C

2016-03-01

An adult male reticulated giraffe (Giraffa camelopardalis reticulata) was presented for postmortem examination. During radiologic examination of the hindlimbs, osseous cyst-like lesions were detected in both medial femoral condyles. These lesions were subsequently examined macroscopically and histologically. The gross appearance suggested a diagnosis of bilateral osteochondrosis that was confirmed with histopathologic examination. This finding has not previously been reported in giraffes. Macroscopic visualization of the major limb joints, including the femorotibial joints, is therefore encouraged in future postmortem examinations of giraffes (Giraffa camelopardalis), and further assessment of clinical significance is required.

Generating macroscopic chaos in a network of globally coupled phase oscillators

PubMed Central

So, Paul; Barreto, Ernest

2011-01-01

We consider an infinite network of globally coupled phase oscillators in which the natural frequencies of the oscillators are drawn from a symmetric bimodal distribution. We demonstrate that macroscopic chaos can occur in this system when the coupling strength varies periodically in time. We identify period-doubling cascades to chaos, attractor crises, and horseshoe dynamics for the macroscopic mean field. Based on recent work that clarified the bifurcation structure of the static bimodal Kuramoto system, we qualitatively describe the mechanism for the generation of such complicated behavior in the time varying case. PMID:21974662

The effect of learning multimedia on students’ understanding of macroscopic, sub-microscopic, and symbolic levels in electrolyte and nonelectrolyte

NASA Astrophysics Data System (ADS)

Eliyawati; Rohman, I.; Kadarohman, A.

2018-05-01

This research aims to investigate the effect of learning multimedia on students’ understanding of macroscopic, sub-microscopic, and symbolic levels in electrolyte and nonelectrolyte topic. The quasi-experimental with one group pre-test post-test design was used. Thirty-five students were experimental class and another thirty-five were control class. The instrument was used is three representation levels. The t-test was performed on average level of 95% to identify the significant difference between experimental class and control class. The results show that the normalized gain average of experimental class is 0.75 (high) and the normalized gain average of control class is 0.45 (moderate). There is significant difference in students’ understanding in sub-microscopic and symbolic levels and there is not significant difference of students’ understanding in macroscopic level between experimental class and control class. The normalized gain of students’ understanding of macroscopic, sub-microscopic and symbolic in experimental class are 0.6 (moderate), 0.75 (high), and 0.64 (moderate), while the normalized gain of students’ understanding of macroscopic, sub-microscopic and symbolic in control class are 0.49 (moderate), 0.39 (high), and 0.3 (moderate). Therefore, it can be concluded that learning multimedia can help in improving students’ understanding especially in sub-microscopic and symbolic levels.

Applications of the microdosimetric function implemented in the macroscopic particle transport simulation code PHITS.

PubMed

Sato, Tatsuhiko; Watanabe, Ritsuko; Sihver, Lembit; Niita, Koji

2012-01-01

Microdosimetric quantities such as lineal energy are generally considered to be better indices than linear energy transfer (LET) for expressing the relative biological effectiveness (RBE) of high charge and energy particles. To calculate their probability densities (PD) in macroscopic matter, it is necessary to integrate microdosimetric tools such as track-structure simulation codes with macroscopic particle transport simulation codes. As an integration approach, the mathematical model for calculating the PD of microdosimetric quantities developed based on track-structure simulations was incorporated into the macroscopic particle transport simulation code PHITS (Particle and Heavy Ion Transport code System). The improved PHITS enables the PD in macroscopic matter to be calculated within a reasonable computation time, while taking their stochastic nature into account. The microdosimetric function of PHITS was applied to biological dose estimation for charged-particle therapy and risk estimation for astronauts. The former application was performed in combination with the microdosimetric kinetic model, while the latter employed the radiation quality factor expressed as a function of lineal energy. Owing to the unique features of the microdosimetric function, the improved PHITS has the potential to establish more sophisticated systems for radiological protection in space as well as for the treatment planning of charged-particle therapy.

Surface-enhanced Raman spectroscopy for the analysis of smokeless gunpowders and macroscopic gunshot residues.

PubMed

López-López, María; Merk, Virginia; García-Ruiz, Carmen; Kneipp, Janina

2016-07-01

Gunshot residues (GSR) result from the discharge of a firearm being a potential piece of evidence in criminal investigations. The macroscopic GSR particles are basically formed by burned and non-burned gunpowder. Motivated by the demand of trace analysis of these samples, in this paper, the use of surface-enhanced Raman scattering (SERS) was evaluated for the analysis of gunpowders and macroscopic GSR particles. Twenty-one different smokeless gunpowders were extracted with ethanol. SERS spectra were obtained from the diluted extracts using gold nanoaggregates and an excitation wavelength of 633 nm. They show mainly bands that could be assigned to the stabilizers diphenylamine and ethylcentralite present in the gunpowders. Then, macroscopic GSR particles obtained after firing two different ammunition cartridges on clothing were also measured using the same procedure. SERS allowed the detection of the particles collected with an aluminum stub from cloth targets without interferences from the adhesive carbon. The results demonstrate the great potential of SERS for the analysis of macroscopic GSR particles. Furthermore, they indicate that the grain-to-grain inhomogeneity of the gunpowders needs to be considered. Graphical Abstract SERS allows the detection of GSR particles collected with adhesive stubs from cloth targets using gold nanoaggregates and an excitation wavelength of 633 nm.

On localization and void coalescence as a precursor to ductile fracture.

PubMed

Tekoğlu, C; Hutchinson, J W; Pardoen, T

2015-03-28

Two modes of plastic flow localization commonly occur in the ductile fracture of structural metals undergoing damage and failure by the mechanism involving void nucleation, growth and coalescence. The first mode consists of a macroscopic localization, usually linked to the softening effect of void nucleation and growth, in either a normal band or a shear band where the thickness of the band is comparable to void spacing. The second mode is coalescence with plastic strain localizing to the ligaments between voids by an internal necking process. The ductility of a material is tied to the strain at macroscopic localization, as this marks the limit of uniform straining at the macroscopic scale. The question addressed is whether macroscopic localization occurs prior to void coalescence or whether the two occur simultaneously. The relation between these two modes of localization is studied quantitatively in this paper using a three-dimensional elastic-plastic computational model representing a doubly periodic array of voids within a band confined between two semi-infinite outer blocks of the same material but without voids. At sufficiently high stress triaxiality, a clear separation exists between the two modes of localization. At lower stress triaxialities, the model predicts that the onset of macroscopic localization and coalescence occur simultaneously. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Phase-field simulation of microstructure formation in technical castings - A self-consistent homoenthalpic approach to the micro-macro problem

NASA Astrophysics Data System (ADS)

Böttger, B.; Eiken, J.; Apel, M.

2009-10-01

Performing microstructure simulation of technical casting processes suffers from the strong interdependency between latent heat release due to local microstructure formation and heat diffusion on the macroscopic scale: local microstructure formation depends on the macroscopic heat fluxes and, in turn, the macroscopic temperature solution depends on the latent heat release, and therefore on the microstructure formation, in all parts of the casting. A self-consistent homoenthalpic approximation to this micro-macro problem is proposed, based on the assumption of a common enthalpy-temperature relation for the whole casting which is used for the description of latent heat production on the macroscale. This enthalpy-temperature relation is iteratively obtained by phase-field simulations on the microscale, thus taking into account the specific morphological impact on the latent heat production. This new approach is discussed and compared to other approximations for the coupling of the macroscopic heat flux to complex microstructure models. Simulations are performed for the binary alloy Al-3at%Cu, using a multiphase-field solidification model which is coupled to a thermodynamic database. Microstructure formation is simulated for several positions in a simple model plate casting, using a one-dimensional macroscopic temperature solver which can be directly coupled to the microscopic phase-field simulation tool.

Macroscopic modeling for heat and water vapor transfer in dry snow by homogenization.

PubMed

Calonne, Neige; Geindreau, Christian; Flin, Frédéric

2014-11-26

Dry snow metamorphism, involved in several topics related to cryospheric sciences, is mainly linked to heat and water vapor transfers through snow including sublimation and deposition at the ice-pore interface. In this paper, the macroscopic equivalent modeling of heat and water vapor transfers through a snow layer was derived from the physics at the pore scale using the homogenization of multiple scale expansions. The microscopic phenomena under consideration are heat conduction, vapor diffusion, sublimation, and deposition. The obtained macroscopic equivalent model is described by two coupled transient diffusion equations including a source term arising from phase change at the pore scale. By dimensional analysis, it was shown that the influence of such source terms on the overall transfers can generally not be neglected, except typically under small temperature gradients. The precision and the robustness of the proposed macroscopic modeling were illustrated through 2D numerical simulations. Finally, the effective vapor diffusion tensor arising in the macroscopic modeling was computed on 3D images of snow. The self-consistent formula offers a good estimate of the effective diffusion coefficient with respect to the snow density, within an average relative error of 10%. Our results confirm recent work that the effective vapor diffusion is not enhanced in snow.

Unified implicit kinetic scheme for steady multiscale heat transfer based on the phonon Boltzmann transport equation

NASA Astrophysics Data System (ADS)

Zhang, Chuang; Guo, Zhaoli; Chen, Songze

2017-12-01

An implicit kinetic scheme is proposed to solve the stationary phonon Boltzmann transport equation (BTE) for multiscale heat transfer problem. Compared to the conventional discrete ordinate method, the present method employs a macroscopic equation to accelerate the convergence in the diffusive regime. The macroscopic equation can be taken as a moment equation for phonon BTE. The heat flux in the macroscopic equation is evaluated from the nonequilibrium distribution function in the BTE, while the equilibrium state in BTE is determined by the macroscopic equation. These two processes exchange information from different scales, such that the method is applicable to the problems with a wide range of Knudsen numbers. Implicit discretization is implemented to solve both the macroscopic equation and the BTE. In addition, a memory reduction technique, which is originally developed for the stationary kinetic equation, is also extended to phonon BTE. Numerical comparisons show that the present scheme can predict reasonable results both in ballistic and diffusive regimes with high efficiency, while the memory requirement is on the same order as solving the Fourier law of heat conduction. The excellent agreement with benchmark and the rapid converging history prove that the proposed macro-micro coupling is a feasible solution to multiscale heat transfer problems.

Making baryons dark: the quantum prediction of the variation of photon-particle scattering cross section with the approach to equilibrium in deep gravity wells

NASA Astrophysics Data System (ADS)

Ernest, Alllan David; Collins, Matthew P.

2015-08-01

Analysis of astrophysical phenomena relies on knowledge of cross sections. These cross sections are measured in scattering experiments, or calculated using theoretical techniques such as partial wave analysis. It has been recently shown [1,2,3] however that photon scattering cross sections depend also on the degree of localization of the target particle, and that particles in large-scale, deep-gravity wells can exhibit lower cross sections than those measured in lab-based experiments where particles are implicitly localized. This purely quantum effect arises as a consequence of differences in the gravitational eigenspectral distribution of a particle’s wavefunction in different situations, and is in addition to the obvious notion that delocalized particle scattering is less likely simply because the target particles are ‘in a bigger box’.In this presentation we consider the quantum equilibrium statistics of particles in gravitational potentials corresponding to dark matter density profiles. We show that as galactic halos approach equilibrium, the dark eigenstates of the eigenspectral ensemble are favoured and baryons exhibit lower photon scattering cross sections, rendering halos less visible than expected from currently accepted cross sections. Traditional quantum theory thus predicts that baryons that have not coalesced into self-bound macroscopic structures such as stars, can essentially behave as dark matter simply by equilibrating within a deep gravity well. We will discuss this effect and the consequences for microwave anisotropy analysis and primordial nucleosynthesis.[1] Ernest, A. D., and Collins, M. P., 2014, Australian Institute of Physics, AIP Congress, Canberra, December, 2014.[2] Ernest, A. D., 2009, J. Phys. A: Math. Theor., 42, 115207, 115208.[3] Ernest, A. D., 2012, In Prof. Ion Cotaescu (Ed) Advances in Quantum Theory (pp 221-248). Rijeka: InTech. ISBN 978-953-51-0087-4

Total and Compound Formation Cross Sections for Americium Nuclei: Recommendations for Coupled-Channels Calculations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Escher, J. E.

Calculations for total cross sections and compound-nucleus (CN) formation cross sections for americium isotopes are described, for use in the 2017 NA-22 evaluation effort. The code ECIS 2006 was used in conjunction with Frank Dietrich's wrapper `runtemplate'.

Electron-impact total ionization cross sections of DNA sugar-phosphate backbone and an additivity principle

NASA Technical Reports Server (NTRS)

Huo, Winifred M.; Dateo, Christopher E.

2005-01-01

The improved binary-encounter dipole (iBED) model [W.M. Huo, Phys. Rev. A64, 042719-1 (2001)l is used to study the total ionization cross sections of the DNA sugar-phosphate backbone by electron impact. Calculations using neutral fragments found that the total ionization cross sections of C3' - and C5', -deoxyribose-phospate, two conformers of the sugar-phosphate backbone, are close to each other. Furthermore, the sum of the ionization cross sections of the separate deoxyribose and phosphate fragments is in close agreement with the C3' - and C5" -deoxyribose-phospate cross sections, differing by less than 10%. The result implies that certain properties of the-DNA, like the total singly ionization cross section, are localized properties and a building-up or additivity principle may apply. This allows us to obtain accurate properties of larger molecular systems built up from the results of smaller subsystem fragments. Calculations are underway using a negatively charged sugar-phosphate backbone with a metal counter-ion.

Can an endocytoscope system (ECS) predict histology in neoplastic lesions?

PubMed

Eberl, T; Jechart, G; Probst, A; Golczyk, M; Bittinger, M; Scheubel, R; Arnholdt, H; Knuechel, R; Messmann, H

2007-06-01

An endocytoscope system (ECS) has recently been developed with the possibility of super-high magnification of gastrointestinal mucosa, thus allowing in vivo imaging of living cells. The aim of the present study was to assess the potential of ECS in the prediction of histology in both normal gastrointestinal mucosa and neoplastic lesions. In total, 76 patients (57 men, 19 women; age range 37-86 years) with neoplastic lesions in the esophagus, stomach, or colon were enrolled into the study and underwent esophagogastroduodenoscopy or colonoscopy. After staining with 1% methylene blue, the mucosa was examined with the ECS probe (x 450 and x 1100 magnification), and video sequences were recorded on video disk. Biopsies from the examined areas were taken for histology and served as the gold standard. The endocytoscope video sequences were evaluated by two blinded pathologists. Finally the results were compared with those resulting from the evaluation of an experienced endoscopist who was aware of the macroscopic endoscopic pictures and the endocytoscope image results. A total of 25 patients with esophageal lesions, 28 patients with colonic lesions, and 23 patients with gastric lesions were examined. The sensitivity and specificity for the evaluation of the blinded pathologists was 81% and 100%, respectively, in the esophagus, 56% and 89% in the stomach, and 79% and 90% in the colon. If an endoscopist evaluated the endocytoscopic pictures in combination with the macroscopic endoscopic images sensitivity and specificity increased significantly. First experiences with ECS show good sensitivity rates even by blinded assessment for esophageal and colonic lesions. Sensitivity for neoplastic lesions in the stomach is lower because of gastric mucous secretion. Combining the endoscopic and cytoscopic appearance of the lesion may further enhance the diagnostic value of the method.

Assessment of the Authenticity of Herbal Dietary Supplements: Comparison of Chemical and DNA Barcoding Methods.

PubMed

Pawar, Rahul S; Handy, Sara M; Cheng, Raymond; Shyong, Nicole; Grundel, Erich

2017-07-01

About 7 % of the U. S. population reports using botanical dietary supplements. Increased use of such supplements has led to discussions related to their authenticity and quality. Reports of adulteration with substandard materials or pharmaceuticals are of concern because such substitutions, whether inadvertent or deliberate, may reduce the efficacy of specific botanicals or lead to adverse events. Methods for verifying the identity of botanicals include macroscopic and microscopic examinations, chemical analysis, and DNA-based methods including DNA barcoding. Macroscopic and microscopic examinations may fail when a supplement consists of botanicals that have been processed beyond the ability to provide morphological characterizations. Chemical analysis of specific marker compounds encounters problems when these compounds are not distinct to a given species or when purified reference standards are not available. Recent investigations describing DNA barcoding analysis of botanical dietary supplements have raised concerns about the authenticity of the supplements themselves as well as the appropriateness of using DNA barcoding techniques with finished botanical products. We collected 112 market samples of frequently consumed botanical dietary supplements of ginkgo, soy, valerian, yohimbe, and St. John's wort and analyzed each for specific chemical markers (i.e., flavonol glycosides, total isoflavones, total valerenic acids, yohimbine, and hypericins, respectively). We used traditional DNA barcoding techniques targeting the nuclear ITS2 gene and the chloroplast gene psb A- trn H on the same samples to determine the presence of DNA of the labelled ingredient. We compared the results obtained by both methods to assess the contribution of each in determining the identity of the samples. Georg Thieme Verlag KG Stuttgart · New York.

Histomorphometry and macroscopic intestinal lesions in broilers infected with Eimeria acervulina.

PubMed

Assis, R C L; Luns, F D; Beletti, M E; Assis, R L; Nasser, N M; Faria, E S M; Cury, M C

2010-03-25

This study aimed at measuring intestinal villi and assessing the intestinal absorptive area in broilers infected with Eimeria acervulina under different treatments to control coccidiosis. The experiment was divided into two stages, carried out in successive housings, raised in the same environment (or aviary). In the first stage, on 25 May 2008, fifty 12-day-old birds were orally inoculated with 3 x 10(3) oocysts of E. acervulina. In the second stage, on July 2008, other 50 birds were allocated on litter contaminated by the feces of birds on the first housing (natural infection by oocysts present in the reused litter). The experiment was arranged in a complete randomized design with five treatments and three replicates of 10 chicks per treatment. Broiler chicks were housed at 1 day of age and autopsies were performed at 21 days of age. Three 2-cm-long segments of the duodenum were excised from each bird and fixed in 10% buffered formalin. A total of 30 slides were prepared for each treatment, totaling 150 evaluated histological sections using H&E staining. Villus morphology was carried out by the HL Image 97 software. The intestinal absorptive area was calculated and macroscopic lesions were classified according to standard lesion scores. Results showed that intestinal villus measurements and absorptive area are directly affected by E. acervulina and that there is direct and positive correlation between the macro and microscopic findings observed in intestinal coccidiosis. E. acervulina causes shortening of villi and reduction in the intestinal absorptive area, affecting broiler growth. The prevention method of litter fermentation during the interval between housings and oral administration of Diclazuril can reduce the severity of intestinal lesions by E. acervulina in broilers impairing oocyst virulence or viability.

Experimental study of low-energy charge transfer in nitrogen

NASA Technical Reports Server (NTRS)

Smith, A.

1979-01-01

Total charge transfer cross sections were obtained for the N2(+)-N2 system with relative translational ion energies between 9 and 441 eV. Data were obtained to examine the dependence of total cross section on ion energy. The effect of ion excitation on the cross sections was studied by varying the electron ionization energy in the mass spectrometer ion source over an electron energy range between 14.5 and 32.1 eV. The dependence of total cross section on the neutralization chamber gas pressure was examined by obtaining data at pressure values from 9.9 to 0.000199 torr. Cross section values obtained were compared with experimental and theoretical results of other investigations.

Effect of low-dose irradiation on structural and mechanical properties of hyaline cartilage-like fibrocartilage.

PubMed

Öncan, Tevfik; Demirağ, Burak; Ermutlu, Cenk; Yalçinkaya, Ulviye; Özkan, Lütfü

2013-01-01

The aim of this study was to analyze the effect of low-dose irradiation on fibrous cartilage and to obtain a hyaline cartilage-like fibrocartilage (HCLF) with similar structural and mechanical properties to hyaline cartilage. An osteochondral defect was created in 40 knees of 20 rabbits. At the 7th postoperative day, a single knee of each rabbit was irradiated with a total dose of 5.0 Gy in 1.0 Gy fractions for 5 days (radiotherapy group), while the other knee was not irradiated (control group). Rabbits were then divided into four groups of 5 rabbits each. The first three groups were sacrificed at the 4th, 8th and the 12th postoperative weeks and cartilage defects were macroscopically and microscopically evaluated. The remaining group of 5 rabbits was sacrificed at the 12th week and biomechanical compression tests were performed on the cartilage defects. There was no significant biomechanical difference between the radiotherapy and the control group (p=0.686). There was no significant macroscopic and microscopic difference between groups (p=0.300). Chondrocyte clustering was observed in the irradiated group. Low-dose irradiation does not affect the mechanical properties of HCLF in vivo. However, structural changes such as chondrocyte clustering were observed.

Alteration of the rat cecal microbiome during colonization with the helminth Hymenolepis diminuta.

PubMed

McKenney, Erin A; Williamson, Lauren; Yoder, Anne D; Rawls, John F; Bilbo, Staci D; Parker, William

2015-01-01

The microbiome is now widely recognized as being important in health and disease, and makes up a substantial subset of the biome within the ecosystem of the vertebrate body. At the same time, multicellular, eukaryotic organisms such as helminths are being recognized as an important component of the biome that shaped the evolution of our genes. The absence of these macroscopic organisms during the early development and life of humans in Western culture probably leads to a wide range of human immunological diseases. However, the interaction between the microbiome and macroscopic components of the biome remains poorly characterized. In this study, the microbiome of the cecum in rats colonized for 2 generations with the small intestinal helminth Hymenolepis diminuta was evaluated. The introduction of this benign helminth, which is of considerable therapeutic interest, led to several changes in the cecal microbiome. Most of the changes were within the Firmicutes phylum, involved about 20% of the total bacteria, and generally entailed a shift from Bacilli to Clostridia species in the presence of the helminth. The results point toward ecological relationships between various components of the biome, with the observed shifts in the microbiome suggesting potential mechanisms by which this helminth might exert therapeutic effects.

Critical insight into the influence of the potential energy surface on fission dynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mazurek, K.; Grand Accelerateur National d'Ions Lourds; Schmitt, C.

The present work is dedicated to a careful investigation of the influence of the potential energy surface on the fission process. The time evolution of nuclei at high excitation energy and angular momentum is studied by means of three-dimensional Langevin calculations performed for two different parametrizations of the macroscopic potential: the Finite Range Liquid Drop Model (FRLDM) and the Lublin-Strasbourg Drop (LSD) prescription. Depending on the mass of the system, the topology of the potential throughout the deformation space of interest in fission is observed to noticeably differ within these two approaches, due to the treatment of curvature effects. Whenmore » utilized in the dynamical calculation as the driving potential, the FRLDM and LSD models yield similar results in the heavy-mass region, whereas the predictions can be strongly dependent on the Potential Energy Surface (PES) for medium-mass nuclei. In particular, the mass, charge, and total kinetic energy distributions of the fission fragments are found to be narrower with the LSD prescription. The influence of critical model parameters on our findings is carefully investigated. The present study sheds light on the experimental conditions and signatures well suited for constraining the parametrization of the macroscopic potential. Its implication regarding the interpretation of available experimental data is briefly discussed.« less

Invasive vulvar carcinoma and the question of the surgical margin.

PubMed

Palaia, Innocenza; Bellati, Filippo; Calcagno, Marco; Musella, Angela; Perniola, Giorgia; Panici, Pierluigi B

2011-08-01

To assess the discrepancy between width of surgical margin measured with the naked eye/ruler by a surgeon before removing an invasive vulvar carcinoma, and width of margin measured under microscope by pathologist after fixation of the resected lesion with formalin. Potential relationships between discrepancy and disease recurrence were also investigated. This prospective study was conducted with resected lesions from 86 women who underwent surgery for primary/recurrent invasive vulvar carcinoma. After the surgeon removed the lesions surrounded by 1-2-cm margins, the pathologist determined margin width at the 4 cardinal points of 86 lesions (for a total of 344 margin assessments), first macroscopically and then under the microscope. A safety margin of 0.8 cm on microscopic view was achieved in 83% of cases (112 of 135) when the macroscopic measurement was 1cm, in 91% of cases (58 of 64) when it was 1.5 cm, and 98% of cases (105 of 107) when it was 2 cm. There was a small discrepancy between the surgeon's intent and the microscopic margin measurement, mostly related to tissue shrinkage. A 1-cm surgical margin corresponded to a 0.8-cm margin in microscopic view (the "safe margin") in most cases. Copyright © 2011 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

Nanoscale Electronic Conditioning for Improvement of Nanowire Light-Emitting-Diode Efficiency.

PubMed

May, Brelon J; Belz, Matthew R; Ahamed, Arshad; Sarwar, A T M G; Selcu, Camelia M; Myers, Roberto C

2018-04-24

Commercial III-Nitride LEDs and lasers spanning visible and ultraviolet wavelengths are based on epitaxial films. Alternatively, nanowire-based III-Nitride optoelectronics offer the advantage of strain compliance and high crystalline quality growth on a variety of inexpensive substrates. However, nanowire LEDs exhibit an inherent property distribution, resulting in uneven current spreading through macroscopic devices that consist of millions of individual nanowire diodes connected in parallel. Despite being electrically connected, only a small fraction of nanowires, sometimes <1%, contribute to the electroluminescence (EL). Here, we show that a population of electrical shorts exists in the devices, consisting of a subset of low-resistance nanowires that pass a large portion of the total current in the ensemble devices. Burn-in electronic conditioning is performed by applying a short-term overload voltage; the nanoshorts experience very high current density, sufficient to render them open circuits, thereby forcing a new current path through more nanowire LEDs in an ensemble device. Current-voltage measurements of individual nanowires are acquired using conductive atomic force microscopy to observe the removal of nanoshorts using burn-in. In macroscopic devices, this results in a 33× increase in peak EL and reduced leakage current. Burn-in conditioning of nanowire ensembles therefore provides a straightforward method to mitigate nonuniformities inherent to nanowire devices.

Alteration of the rat cecal microbiome during colonization with the helminth Hymenolepis diminuta

PubMed Central

McKenney, Erin A; Williamson, Lauren; Yoder, Anne D; Rawls, John F; Bilbo, Staci D; Parker, William

2015-01-01

The microbiome is now widely recognized as being important in health and disease, and makes up a substantial subset of the biome within the ecosystem of the vertebrate body. At the same time, multicellular, eukaryotic organisms such as helminths are being recognized as an important component of the biome that shaped the evolution of our genes. The absence of these macroscopic organisms during the early development and life of humans in Western culture probably leads to a wide range of human immunological diseases. However, the interaction between the microbiome and macroscopic components of the biome remains poorly characterized. In this study, the microbiome of the cecum in rats colonized for 2 generations with the small intestinal helminth Hymenolepis diminuta was evaluated. The introduction of this benign helminth, which is of considerable therapeutic interest, led to several changes in the cecal microbiome. Most of the changes were within the Firmicutes phylum, involved about 20% of the total bacteria, and generally entailed a shift from Bacilli to Clostridia species in the presence of the helminth. The results point toward ecological relationships between various components of the biome, with the observed shifts in the microbiome suggesting potential mechanisms by which this helminth might exert therapeutic effects. PMID:25942385

Upscaling of spectral induced polarization response using random tube networks

NASA Astrophysics Data System (ADS)

Maineult, Alexis; Revil, André; Camerlynck, Christian; Florsch, Nicolas; Titov, Konstantin

2017-05-01

In order to upscale the induced polarization (IP) response of porous media, from the pore scale to the sample scale, we implement a procedure to compute the macroscopic complex resistivity response of random tube networks. A network is made of a 2-D square-meshed grid of connected tubes, which obey to a given tube radius distribution. In a simplified approach, the electrical impedance of each tube follows a local Pelton resistivity model, with identical resistivity, chargeability and Cole-Cole exponent values for all the tubes-only the time constant varies, as it depends on the radius of each tube and on a diffusion coefficient also identical for all the tubes. By solving the conservation law for the electrical charge, the macroscopic IP response of the network is obtained. We fit successfully the macroscopic complex resistivity also by a Pelton resistivity model. Simulations on uncorrelated and correlated networks, for which the tube radius distribution is so that the decimal logarithm of the radius is normally distributed, evidence that the local and macroscopic model parameters are the same, except the Cole-Cole exponent: its macroscopic value diminishes with increasing heterogeneity (i.e. with increasing standard deviation of the radius distribution), compared to its local value. The methodology is also applied to six siliciclastic rock samples, for which the pore radius distributions from mercury porosimetry are available. These samples exhibit the same behaviour as synthetic media, that is, the macroscopic Cole-Cole exponent is always lower than the local one. As a conclusion, the pore network method seems to be a promising tool for studying the upscaling of the IP response of porous media.

Dynamic and temperature dependent response of physical vapor deposited Se in freely standing nanometric thin films

NASA Astrophysics Data System (ADS)

Yoon, Heedong; McKenna, Gregory B.

2016-05-01

Here, we report results from an investigation of nano-scale size or confinement effects on the glass transition and viscoelastic properties of physical vapor deposited selenium films. The viscoelastic response of freely standing Se films was determined using a biaxial membrane inflation or bubble inflation method [P. A. O'Connell and G. B. McKenna, Science 307, 1760-1763 (2005)] on films having thicknesses from 60 to 267 nm and over temperatures ranging from Tg, macroscopic - 15 °C to Tg, macroscopic + 21 °C. Time-temperature superposition and time-thickness superposition were found to hold for the films in the segmental dispersion. The responses are compared with macroscopic creep and recoverable creep compliance data for selenium [K. M. Bernatz et al., J. Non-Cryst. Solids 307, 790-801 (2002)]. The time-temperature shift factors for the thin films show weaker temperature dependence than seen in the macroscopic behavior, being near to Arrhenius-like in their temperature dependence. Furthermore, the Se films exhibit a "rubbery-like" stiffening that increases as film thickness decreases similar to prior observations [P. A. O'Connell et al., Macromolecules 45(5), 2453-2459 (2012)] for organic polymers. In spite of the differences from the macroscopic behavior in the temperature dependence of the viscoelastic response, virtually no change in Tg as determined from the thickness dependence of the retardation time defining Tg was observed in the bubble inflation creep experiments to thicknesses as small as 60 nm. We also find that the observed rubbery stiffening is consistent with the postulate of K. L. Ngai et al. [J. Polym. Sci., Part B: Polym. Phys. 51(3), 214-224 (2013)] that it should correlate with the change of the macroscopic segmental relaxation.

Understanding Local and Macroscopic Electron Mobilities in the Fullerene Network of Conjugated Polymer-based Solar Cells. Time-Resolved Microwave Conductivity and Theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aguirre, Jordan C.; Arntsen, Christopher D.; Hernandez, Samuel

2013-09-23

The efficiency of bulk heterojunction (BHJ) organic photovoltaics is sensitive to the morphology of the fullerene network that transports electrons through the device. This sensitivity makes it difficult to distinguish the contrasting roles of local electron mobility (how easily electrons can transfer between neighboring fullerene molecules) and macroscopic electron mobility (how well-connected is the fullerene network on device length scales) in solar cell performance. In this work, a combination of density functional theory (DFT) calculations, flash-photolysis time-resolved microwave conductivity (TRMC) experiments, and space-charge-limit current (SCLC) mobility estimates are used to examine the roles of local and macroscopic electron mobility inmore » conjugated polymer/fullerene BHJ photovoltaics. The local mobility of different pentaaryl fullerene derivatives (so-called ‘shuttlecock’ molecules) is similar, so that differences in solar cell efficiency and SCLC mobilities result directly from the different propensities of these molecules to self-assemble on macroscopic length scales. These experiments and calculations also demonstrate that the local mobility of phenyl-C60 butyl methyl ester (PCBM) is an order of magnitude higher than that of other fullerene derivatives, explaining why PCBM has been the acceptor of choice for conjugated polymer BHJ devices even though it does not form an optimal macroscopic network. The DFT calculations indicate that PCBM's superior local mobility comes from the near-spherical nature of its molecular orbitals, which allow strong electronic coupling between adjacent molecules. In combination, DFT and TRMC techniques provide a tool for screening new fullerene derivatives for good local mobility when designing new molecules that can improve on the macroscopic electron mobility offered by PCBM.« less

Bell inequalities for falsifying mesoscopic local realism via amplification of quantum noise

NASA Astrophysics Data System (ADS)

Reid, M. D.

2018-04-01

Macroscopic realism (MR) per se specifies that a system which has two macroscopically distinct states available to it (such as a cat being dead or alive) is at all times predetermined to be in one or other of those two states. A minimal assumption of a macroscopic realistic theory therefore is the validity of a hidden variable λM that predetermines the outcome (whether dead or alive) of a measurement M ̂ distinguishing the two states. Proposals to test MR generally introduce a second premise to further qualify the meaning of MR. Thus, we consider a model, macroscopic local realism (MLR), where the second premise is that measurements at one location cannot cause an instantaneous macroscopic change δ to the results of measurements made on a second system at another location. To provide a practical test, we define the intermediate concept of δ -scopic local realism (δ -LR), where δ ≠0 can be quantified, but need not be macroscopic. By considering the amplification of quantum fluctuations, we show how negation of δ -LR is possible using fields violating a continuous variable Bell inequality. A modified Bell-Clauser-Horne-Shimony-Holt inequality is derived that tests δ -LR, and a quantitative proposal given for experiments based on polarization entanglement. In the proposal, δ is the magnitude of the quantum noise scaled by an adjustable coherent amplitude α that can also be considered part of the measurement apparatus. Thus, δ is large in an absolute sense, but scales inversely with the square root of the system size, which is proportional to |α| 2. We discuss how the proposed experiment gives a realization of a type of Schrödinger-cat experiment without problems of decoherence.

Macroscopic Hematuria After Conventional or Hypofractionated Radiation Therapy: Results From a Prospective Phase 3 Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sanguineti, Giuseppe, E-mail: sanguineti@ifo.it; Arcidiacono, Fabio; Landoni, Valeria

2016-10-01

Purpose: To assess the macroscopic hematuria rates within a single-institution randomized phase 3 trial comparing dose-escalated, conventionally fractionated radiation therapy (CFRT) and moderately hypofractionated radiation therapy (MHRT) for localized prostate cancer. Methods and Materials: Patients with intermediate- to high-risk localized prostate cancer were treated with conformal RT and short-course androgen deprivation. Both the prostate and the entire seminal vesicles were treated to 80 Gy in 40 fractions over 8 weeks (CFRT) or 62 Gy in 20 fractions over 5 weeks (MHRT). The endpoint of the present study was the development of any episode or grade of macroscopic hematuria. The median follow-up period was 93 monthsmore » (range 6-143). Results: Macroscopic hematuria was reported by 25 of 168 patients (14.9%). The actuarial estimate of hematuria at 8 years was 17.0% (95% confidence interval [CI] 10.7%-23.3%). The number of patients with hematuria was 6 and 19 in the CFRT and MHRT arms, respectively, for an actuarial 8-year estimate of 9.7% and 24.3%, respectively (hazard ratio 3.468, 95% CI 1.385-8.684; P=.008). Overall, 8 of 25 patients were found to have biopsy-proven urothelial carcinoma (3 in the CFRT arm and 5 in the MHRT arm; P=.27). Thus, the 8-year actuarial incidence of macroscopic hematuria (after censoring urothelial cancer–related episodes) was 4.1% and 18.2% after CFRT and MHRT, respectively (hazard ratio 4.961, 95% CI 1.426-17.263; P=.012). The results were confirmed by multivariate analysis after accounting for several patient-, treatment-, and tumor-related covariates. Conclusions: MHRT was associated with a statistically significant increased risk of macroscopic hematuria compared with CFRT.« less

The effects of stream crossings on total suspended sediment in North Carolina Piedmont forests

Treesearch

Johnny Boggs; Ge Sun; Steve McNulty

2017-01-01

This study determined total suspended sediment (TSS) at six stream crossings that represented a range of site conditions and forest operations in the Piedmont of North Carolina. Two wood and three steel bridgemats and one culvert were installed to cross the streams. The road classes for the crossings included four temporary skid trails and two permanent forest haul...

Predicting the Macroscopic Fracture Energy of Epoxy Resins from Atomistic Molecular Simulations

DOE PAGES

Meng, Zhaoxu; Bessa, Miguel A.; Xia, Wenjie; ...

2016-12-06

Predicting the macroscopic fracture energy of highly crosslinked glassy polymers from atomistic simulations is challenging due to the size of the process zone being large in these systems. Here, we present a scale-bridging approach that links atomistic molecular dynamics simulations to macroscopic fracture properties on the basis of a continuum fracture mechanics model for two different epoxy materials. Our approach reveals that the fracture energy of epoxy resins strongly depends on the functionality of epoxy resin and the component ratio between the curing agent (amine) and epoxide. The most intriguing part of our study is that we demonstrate that themore » fracture energy exhibits a maximum value within the range of conversion degrees considered (from 65% to 95%), which can be attributed to the combined effects of structural rigidity and post-yield deformability. Our study provides physical insight into the molecular mechanisms that govern the fracture characteristics of epoxy resins and demonstrates the success of utilizing atomistic molecular simulations towards predicting macroscopic material properties.« less

A constitutive model and numerical simulation of sintering processes at macroscopic level

NASA Astrophysics Data System (ADS)

Wawrzyk, Krzysztof; Kowalczyk, Piotr; Nosewicz, Szymon; Rojek, Jerzy

2018-01-01

This paper presents modelling of both single and double-phase powder sintering processes at the macroscopic level. In particular, its constitutive formulation, numerical implementation and numerical tests are described. The macroscopic constitutive model is based on the assumption that the sintered material is a continuous medium. The parameters of the constitutive model for material under sintering are determined by simulation of sintering at the microscopic level using a micro-scale model. Numerical tests were carried out for a cylindrical specimen under hydrostatic and uniaxial pressure. Results of macroscopic analysis are compared against the microscopic model results. Moreover, numerical simulations are validated by comparison with experimental results. The simulations and preparation of the model are carried out by Abaqus FEA - a software for finite element analysis and computer-aided engineering. A mechanical model is defined by the user procedure "Vumat" which is developed by the first author in Fortran programming language. Modelling presented in the paper can be used to optimize and to better understand the process.

Predicting the Macroscopic Fracture Energy of Epoxy Resins from Atomistic Molecular Simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meng, Zhaoxu; Bessa, Miguel A.; Xia, Wenjie

Predicting the macroscopic fracture energy of highly crosslinked glassy polymers from atomistic simulations is challenging due to the size of the process zone being large in these systems. Here, we present a scale-bridging approach that links atomistic molecular dynamics simulations to macroscopic fracture properties on the basis of a continuum fracture mechanics model for two different epoxy materials. Our approach reveals that the fracture energy of epoxy resins strongly depends on the functionality of epoxy resin and the component ratio between the curing agent (amine) and epoxide. The most intriguing part of our study is that we demonstrate that themore » fracture energy exhibits a maximum value within the range of conversion degrees considered (from 65% to 95%), which can be attributed to the combined effects of structural rigidity and post-yield deformability. Our study provides physical insight into the molecular mechanisms that govern the fracture characteristics of epoxy resins and demonstrates the success of utilizing atomistic molecular simulations towards predicting macroscopic material properties.« less

The effect of interlayer adhesion on the mechanical behaviors of macroscopic graphene oxide papers.

PubMed

Gao, Yun; Liu, Lu-Qi; Zu, Sheng-Zhen; Peng, Ke; Zhou, Ding; Han, Bao-Hang; Zhang, Zhong

2011-03-22

High mechanical performances of macroscopic graphene oxide (GO) papers are attracting great interest owing to their merits of lightweight and multiple functionalities. However, the loading role of individual nanosheets and its effect on the mechanical properties of the macroscopic GO papers are not yet well understood. Herein, we effectively tailored the interlayer adhesions of the GO papers by introducing small molecules, that is, glutaraldehyde (GA) and water molecules, into the gallery regions. With the help of in situ Raman spectroscopy, we compared the varied load-reinforcing roles of nanosheets, and further predicted the Young's moduli of the GO papers. Systematic mechanical tests have proven that the enhancement of the tensile modulus and strength of the GA-treated GO paper arose from the improved load-bearing capability of the nanosheets. On the basis of Raman and macroscopic mechanical tests, the influences of interlayer adhesions on the fracture mechanisms of the strained GO papers were inferred.

A macroscopic plasma Lagrangian and its application to wave interactions and resonances

NASA Technical Reports Server (NTRS)

Peng, Y. K. M.

1974-01-01

The derivation of a macroscopic plasma Lagrangian is considered, along with its application to the description of nonlinear three-wave interaction in a homogeneous plasma and linear resonance oscillations in a inhomogeneous plasma. One approach to obtain the Lagrangian is via the inverse problem of the calculus of variations for arbitrary first and second order quasilinear partial differential systems. Necessary and sufficient conditions for the given equations to be Euler-Lagrange equations of a Lagrangian are obtained. These conditions are then used to determine the transformations that convert some classes of non-Euler-Lagrange equations to Euler-Lagrange equation form. The Lagrangians for a linear resistive transmission line and a linear warm collisional plasma are derived as examples. Using energy considerations, the correct macroscopic plasma Lagrangian is shown to differ from the velocity-integrated low Lagrangian by a macroscopic potential energy that equals twice the particle thermal kinetic energy plus the energy lost by heat conduction.

Healable thermoset polymer composite embedded with stimuli-responsive fibres

PubMed Central

Li, Guoqiang; Meng, Harper; Hu, Jinlian

2012-01-01

Severe wounds in biological systems such as human skin cannot heal themselves, unless they are first stitched together. Healing of macroscopic damage in thermoset polymer composites faces a similar challenge. Stimuli-responsive shape-changing polymeric fibres with outstanding mechanical properties embedded in polymers may be able to close macro-cracks automatically upon stimulation such as heating. Here, a stimuli-responsive fibre (SRF) with outstanding mechanical properties and supercontraction capability was fabricated for the purpose of healing macroscopic damage. The SRFs and thermoplastic particles (TPs) were incorporated into regular thermosetting epoxy for repeatedly healing macroscopic damages. The system works by mimicking self-healing of biological systems such as human skin, close (stitch) then heal, i.e. close the macroscopic crack through the thermal-induced supercontraction of the SRFs, and bond the closed crack through melting and diffusing of TPs at the crack interface. The healing efficiency determined using tapered double-cantilever beam specimens was 94 per cent. The self-healing process was reasonably repeatable. PMID:22896563

Designed Er(3+)-singly doped NaYF4 with double excitation bands for simultaneous deep macroscopic and microscopic upconverting bioimaging.

PubMed

Wen, Xuanyuan; Wang, Baoju; Wu, Ruitao; Li, Nana; He, Sailing; Zhan, Qiuqiang

2016-06-01

Simultaneous deep macroscopic imaging and microscopic imaging is in urgent demand, but is challenging to achieve experimentally due to the lack of proper fluorescent probes. Herein, we have designed and successfully synthesized simplex Er(3+)-doped upconversion nanoparticles (UCNPs) with double excitation bands for simultaneous deep macroscopic and microscopic imaging. The material structure and the excitation wavelength of Er(3+)-singly doped UCNPs were further optimized to enhance the upconversion emission efficiency. After optimization, we found that NaYF4:30%Er(3+)@NaYF4:2%Er(3+) could simultaneously achieve efficient two-photon excitation (2PE) macroscopic tissue imaging and three-photon excitation (3PE) deep microscopic when excited by 808 nm continuous wave (CW) and 1480 nm CW lasers, respectively. In vitro cell imaging and in vivo imaging have also been implemented to demonstrate the feasibility and potential of the proposed simplex Er(3+)-doped UCNPs as bioprobe.

End-Group Effects on the Properties of PEG-co-PGA Hydrogels

PubMed Central

Bencherif, Sidi A.; Srinivasan, Abiraman; Sheehan, Jeffrey A.; Walker, Lynn M.; Gayathri, Chakicherla; Gil, Roberto; Hollinger, Jeffrey O.; Matyjaszewski, Krzysztof; Washburn, Newell R.

2009-01-01

A series of resorbable poly(ethylene glycol)-co-poly(glycolic acid) macromonomers have been synthesized with the chemistries from three different photopolymerizable end-groups (acrylates, methacrylates, and urethane methacrylates). The aim of the study is to examine the effects of the chemistry of the cross-linker group on the properties of photocross-linkable hydrogels. PEG-co-PGA (4KG5) hydrogels were prepared by photopolymerization with high vinyl group conversion as confirmed by 1H NMR spectroscopy using DOSY 1D pulse sequence. Our study reveals that the nature of end-groups in a moderately amphiphilic polymer can adjust the distribution and size of the micellar configuration in water leading to changes in the macroscopic structure of hydrogels. By varying the chemistry of the cross-linker group (diacrylates; DA, dimethacrylates; DM, and urethane dimethacrylates; UDM), we determined that the hydrophobocity of a single core polymer consisting of poly(glycolic acid) could be fine-tuned leading to significant variations in the mechanical, swelling, and degradation properties of the gels. In addition, the effects of cross-linker chemistry on cytotoxicity and proliferation were examined. Cytotoxicity assays showed that all the three types of hydrogels (4KG5 DA, DM, and UDM) were biocompatible and the introduction of RGD ligand enhanced cell adhesion. However, differences in gel properties and stability differentially affected the spreading and proliferation of myoblast C2C12 cells. PMID:19328754

Supramolecular Architectures and Mimics of Complex Natural Folds Derived from Rationally Designed alpha-Helical Protein Structures

NASA Astrophysics Data System (ADS)

Tavenor, Nathan Albert

Protein-based supramolecular polymers (SMPs) are a class of biomaterials which draw inspiration from and expand upon the many examples of complex protein quaternary structures observed in nature: collagen, microtubules, viral capsids, etc. Designing synthetic supramolecular protein scaffolds both increases our understanding of natural superstructures and allows for the creation of novel materials. Similar to small-molecule SMPs, protein-based SMPs form due to self-assembly driven by intermolecular interactions between monomers, and monomer structure determines the properties of the overall material. Using protein-based monomers takes advantage of the self-assembly and highly specific molecular recognition properties encodable in polypeptide sequences to rationally design SMP architectures. The central hypothesis underlying our work is that alpha-helical coiled coils, a well-studied protein quaternary folding motif, are well-suited to SMP design through the addition of synthetic linkers at solvent-exposed sites. Through small changes in the structures of the cross-links and/or peptide sequence, we have been able to control both the nanoscale organization and the macroscopic properties of the SMPs. Changes to the linker and hydrophobic core of the peptide can be used to control polymer rigidity, stability, and dimensionality. The gaps in knowledge that this thesis sought to fill on this project were 1) the relationship between the molecular structure of the cross-linked polypeptides and the macroscopic properties of the SMPs and 2) a means of creating materials exhibiting multi-dimensional net or framework topologies. Separate from the above efforts on supramolecular architectures was work on improving backbone modification strategies for an alpha-helix in the context of a complex protein tertiary fold. Earlier work in our lab had successfully incorporated unnatural building blocks into every major secondary structure (beta-sheet, alpha-helix, loops and beta-turns) of a small protein with a tertiary fold. Although the tertiary fold of the native sequence was mimicked by the resulting artificial protein, the thermodynamic stability was greatly compromised. Most of this energetic penalty derived from the modifications present in the alpha-helix. The contribution within this thesis was direct comparison of several alpha-helical design strategies and establishment of the thermodynamic consequences of each.

Nondestructive evaluation of loading and fatigue effects in Haynes(R) 230(R) alloy

NASA Astrophysics Data System (ADS)

Saleh, Tarik Adel

Nondestructive evaluation is a useful method for studying the effects of deformation and fatigue. In this dissertation I employed neutron and X-ray diffraction, nonlinear resonant ultrasound spectroscopy (NRUS), and infrared thermography to study the effects of deformation and fatigue on two different nickel based superalloys. The alloys studied were HAYNES 230, a solid solution strengthened alloy with 4% M6C carbides, and secondarily HASTELLOY C-2000 a similar single phase alloy. Using neutron and X-ray diffraction, the deformation behavior of HAYNES 230 was revealed to be composite-like during compression, but unusual in tension, where the carbides provide strengthening until just after the macroscopic yield strength and then they begin to debond and crack, creating a tension-compression asymmetry that is revealed clearly by in situ diffraction. In fatigue of HAYNES 230, the hkl elastic strains changed very little in tension-tension fatigue. However, in situ tension-compression studies showed large changes over the initial stages of fatigue. The HAYNES 230 samples studies had two distinct starting textures, measured by neutron diffraction. Some samples were texture free initially and deformed in tension and compression to fiber textures. Other samples started with a bimodal texture due to cross-rolling and incomplete annealing. The final texture of these bimodal samples is shown through modeling to be a superposition of the initial texture and typical FCC deformation mechanisms. The texture-free samples deformed significantly more macroscopically and in internal elastic strains than the samples with the cross-rolled texture. In contrast to the relative insensitivity of neutron diffraction to the effects of tension-tension fatigue, NRUS revealed large differences between as-received and progressively fatigued samples. This showed that microcracking and void formation are the primary mechanisms responsible for fatigue damage in tension-tension fatigue. NRUS is shown to be a useful complimentary technique to neutron diffraction to evaluate fatigue damage. Finally, infrared thermography is used to show temperature changes over the course of fatigue in HASTELLOY C-2000. Four stages of temperature are shown over the course of a single fatigue test. Both empirical and theoretical relationships between steady state temperature and fatigue life are developed and presented.

On a chiral analog of the Einstein-de Haas effect

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zakharov, V. I., E-mail: vzakharov@itep.ru

The Einstein-de Haas effect reveals a transfer of angular momentum from microscopic constituents (electrons) to a macroscopic body, but in the case of massless fermions, one could expect the transfer of the chirality of constituents to macroscopic helical motion. For such a picture to be consistent, the macroscopic helicity is to be conserved classically, to echo the conservation of the angular momentum of a rotating body. The helicity conservation would in turn impose constraints on hydrodynamics of chiral liquids (whose constituents are massless fermions). Essentially, the chiral liquids are dissipation-free, on the classical level. Reservations and alternatives to this scenariomore » are discussed.« less

Plasmonic direct writing lithography with a macroscopical contact probe

NASA Astrophysics Data System (ADS)

Huang, Yuerong; Liu, Ling; Wang, Changtao; Chen, Weidong; Liu, Yunyue; Li, Ling

2018-05-01

In this work, we design a plasmonic direct writing lithography system with a macroscopical contact probe to achieve nanometer scale spots. The probe with bowtie-shaped aperture array adopts spring hinge and beam deflection method (BDM) to realize near-field lithography. Lithography results show that a macroscopical plasmonic contact probe can achieve a patterning resolution of around 75 nm at 365 nm wavelength, and demonstrate that the lithography system is promising for practical applications due to beyond the diffraction limit, low cost, and simplification of system configuration. CST calculations provide a guide for the design of recording structure and the arrangement of placing polarizer.

MACROSCOPIC PATTERNS OF BACTERIA AFTER DEVELOPMENT IN DROPS OF LIQUID MEDIUM

PubMed Central

Lorian, Victor

1963-01-01

Lorian, Victor (Laboratório Central de Tuberculose, Rio de Janeiro, Brazil). Macroscopic patterns of bacteria after development in drops of liquid medium. J. Bacteriol. 86:582–584. 1963.—Cultures of bacteria in liquid media with 0.06% triphenyltetrazolium hydrochloride showed visible macroscopic development and a characteristic pattern for each strain, when deposited in 0.35-ml drops on the surface of silicone-coated glass or in concavities of slides, after 3 to 4 hr of immobility in an incubator at 37 C. These patterns could be due to sedimentation or autoagglutination occurring as the bacteria developed under these conditions. Images PMID:14066441

Coarse analysis of collective behaviors: Bifurcation analysis of the optimal velocity model for traffic jam formation

NASA Astrophysics Data System (ADS)

Miura, Yasunari; Sugiyama, Yuki

2017-12-01

We present a general method for analyzing macroscopic collective phenomena observed in many-body systems. For this purpose, we employ diffusion maps, which are one of the dimensionality-reduction techniques, and systematically define a few relevant coarse-grained variables for describing macroscopic phenomena. The time evolution of macroscopic behavior is described as a trajectory in the low-dimensional space constructed by these coarse variables. We apply this method to the analysis of the traffic model, called the optimal velocity model, and reveal a bifurcation structure, which features a transition to the emergence of a moving cluster as a traffic jam.

Macroscopic Electrical Wires from Vapor Deposited Poly(3,4-ethylenedioxythiophene).

PubMed

Koch, Lukas; Polek, Anna; Rudd, Sam; Evans, Drew

2017-01-11

Conducting polymers represent a field of materials innovation that bridges the properties of metals (electrical conduction) with those of traditional polymers (mechanical flexibility). Although electronic properties have been studied, minimal attention is given to their mechanical properties such as tensile strength. This study presents macroscopic wires made from the vapor phase polymerization of poly(3,4-ethylenedioxythiophene) using triblock copolymers as a molecular template. These macroscopic wires are conductive (up to 5 × 10 4 S/m), and possess tensile properties (Young's modulus ∼1.1 GPa; tensile strength ∼90 MPa) comparable to commercially available polymers (Nylon-6 and poly(methyl methacrylate)), without need for nonconductive mechanical fillers.

Statistical foundations of liquid-crystal theory

PubMed Central

Seguin, Brian; Fried, Eliot

2013-01-01

Working on a state space determined by considering a discrete system of rigid rods, we use nonequilibrium statistical mechanics to derive macroscopic balance laws for liquid crystals. A probability function that satisfies the Liouville equation serves as the starting point for deriving each macroscopic balance. The terms appearing in the derived balances are interpreted as expected values and explicit formulas for these terms are obtained. Among the list of derived balances appear two, the tensor moment of inertia balance and the mesofluctuation balance, that are not standard in previously proposed macroscopic theories for liquid crystals but which have precedents in other theories for structured media. PMID:23554513

Hybrid Quantum Systems with Trapped Charged Particles

NASA Astrophysics Data System (ADS)

Kotler, Shlomi; Leibfried, Dietrich; Simmonds, Raymond; Wineland, Dave

We will review a joint effort by the Ion Storage Group and the Advanced Microwave Photonics Group at NIST (Boulder, CO) to design a hybrid system that interfaces charged particles with macroscopic high-Q resonators. We specifically consider coupling trapped charges to superconducting LC resonators, the mechanical modes of Silicon-Nitride membranes, and piezo-electric materials. We aim to achieve the strong coupling regime, where a single quantum of motion of the trapped charge can be coherently exchanged with harmonic motion of the macroscopic entity (electrical and/or mechanical). These kind of devices could potentially take advantage of both macroscopic control techniques and the long quantum coherence of its trapped charged particles.

Microscopic Lagrangian description of warm plasmas. IV - Macroscopic approximation

NASA Technical Reports Server (NTRS)

Kim, H.; Crawford, F. W.

1983-01-01

The averaged-Lagrangian method is applied to linear wave propagation and nonlinear three-wave interaction in a warm magnetoplasma, in the macroscopic approximation. The microscopic Lagrangian treated by Kim and Crawford (1977) and by Galloway and Crawford (1977) is first expanded to third order in perturbation. Velocity integration is then carried out, before applying Hamilton's principle to obtain a general description of wave propagation and coupling. The results are specialized to the case of interaction between two electron plasma waves and an Alfven wave. The method is shown to be more powerful than the alternative possibility of working from the beginning with a macroscopic Lagrangian density.

The rapid manufacture of uniform composite multicellular-biomaterial micropellets, their assembly into macroscopic organized tissues, and potential applications in cartilage tissue engineering.

PubMed

Babur, Betul Kul; Kabiri, Mahboubeh; Klein, Travis Jacob; Lott, William B; Doran, Michael Robert

2015-01-01

We and others have published on the rapid manufacture of micropellet tissues, typically formed from 100-500 cells each. The micropellet geometry enhances cellular biological properties, and in many cases the micropellets can subsequently be utilized as building blocks to assemble complex macrotissues. Generally, micropellets are formed from cells alone, however when replicating matrix-rich tissues such as cartilage it would be ideal if matrix or biomaterials supplements could be incorporated directly into the micropellet during the manufacturing process. Herein we describe a method to efficiently incorporate donor cartilage matrix into tissue engineered cartilage micropellets. We lyophilized bovine cartilage matrix, and then shattered it into microscopic pieces having average dimensions < 10 μm diameter; we termed this microscopic donor matrix "cartilage dust (CD)". Using a microwell platform, we show that ~0.83 μg CD can be rapidly and efficiently incorporated into single multicellular aggregates formed from 180 bone marrow mesenchymal stem/stromal cells (MSC) each. The microwell platform enabled the rapid manufacture of thousands of replica composite micropellets, with each micropellet having a material/CD core and a cellular surface. This micropellet organization enabled the rapid bulking up of the micropellet core matrix content, and left an adhesive cellular outer surface. This morphological organization enabled the ready assembly of the composite micropellets into macroscopic tissues. Generically, this is a versatile method that enables the rapid and uniform integration of biomaterials into multicellular micropellets that can then be used as tissue building blocks. In this study, the addition of CD resulted in an approximate 8-fold volume increase in the micropellets, with the donor matrix functioning to contribute to an increase in total cartilage matrix content. Composite micropellets were readily assembled into macroscopic cartilage tissues; the incorporation of CD enhanced tissue size and matrix content, but did not enhance chondrogenic gene expression.

Effects of the soil pore network architecture on the soil's physical functionalities

NASA Astrophysics Data System (ADS)

Smet, Sarah; Beckers, Eléonore; Léonard, Angélique; Degré, Aurore

2017-04-01

The soil fluid movement's prediction is of major interest within an agricultural or environmental scope because many processes depend ultimately on the soil fluids dynamic. It is common knowledge that the soil microscopic pore network structure governs the inner-soil convective fluids flow. There isn't, however, a general methodthat consider the pore network structure as a variable in the prediction of thecore scale soil's physical functionalities. There are various possible representations of the microscopic pore network: sample scale averaged structural parameters, extrapolation of theoretic pore network, or use of all the information available by modeling within the observed pore network. Different representations implydifferent analyzing methodologies. To our knowledge, few studies have compared the micro-and macroscopic soil's characteristics for the same soil core sample. The objective of our study is to explore the relationship between macroscopic physical properties and microscopic pore network structure. The saturated hydraulic conductivity, the air permeability, the retention curve, and others classical physical parameters were measured for ten soil samples from an agricultural field. The pore network characteristics were quantified through the analyses of X-ray micro-computed tomographic images(micro-CT system Skyscan-1172) with a voxel size of 22 µm3. Some of the first results confirmed what others studies had reported. Then, the comparison between macroscopic properties and microscopic parameters suggested that the air movements depended mostly on the pore connectivity and tortuosity than on the total porosity volume. We have also found that the fractal dimension calculated from the X-ray images and the fractal dimension calculated from the retention curve were significantly different. Our communication will detailthose results and discuss the methodology: would the results be similar with a different voxel size? What are the calculated and measured parameters uncertainties? Sarah Smet, as a research fellow, acknowledges the support of the National Fund for Scientific Research (Brussels, Belgium).

MULTISCALE MODELS OF TAXIS-DRIVEN PATTERNING IN BACTERIAL POPULATIONS

PubMed Central

XUE, CHUAN; OTHMER, HANS G.

2009-01-01

Spatially-distributed populations of various types of bacteria often display intricate spatial patterns that are thought to result from the cellular response to gradients of nutrients or other attractants. In the past decade a great deal has been learned about signal transduction, metabolism and movement in E. coli and other bacteria, but translating the individual-level behavior into population-level dynamics is still a challenging problem. However, this is a necessary step because it is computationally impractical to use a strictly cell-based model to understand patterning in growing populations, since the total number of cells may reach 1012 - 1014 in some experiments. In the past phenomenological equations such as the Patlak-Keller-Segel equations have been used in modeling the cell movement that is involved in the formation of such patterns, but the question remains as to how the microscopic behavior can be correctly described by a macroscopic equation. Significant progress has been made for bacterial species that employ a “run-and-tumble” strategy of movement, in that macroscopic equations based on simplified schemes for signal transduction and turning behavior have been derived [14, 15]. Here we extend previous work in a number of directions: (i) we allow for time-dependent signals, which extends the applicability of the equations to natural environments, (ii) we use a more general turning rate function that better describes the biological behavior, and (iii) we incorporate the effect of hydrodynamic forces that arise when cells swim in close proximity to a surface. We also develop a new approach to solving the moment equations derived from the transport equation that does not involve closure assumptions. Numerical examples show that the solution of the lowest-order macroscopic equation agrees well with the solution obtained from a Monte Carlo simulation of cell movement under a variety of temporal protocols for the signal. We also apply the method to derive equations of chemotactic movement that are governed by multiple chemotactic signals. PMID:19784399

The Rapid Manufacture of Uniform Composite Multicellular-Biomaterial Micropellets, Their Assembly into Macroscopic Organized Tissues, and Potential Applications in Cartilage Tissue Engineering

PubMed Central

Kul Babur, Betul; Kabiri, Mahboubeh; Klein, Travis Jacob; Lott, William B.; Doran, Michael Robert

2015-01-01

We and others have published on the rapid manufacture of micropellet tissues, typically formed from 100–500 cells each. The micropellet geometry enhances cellular biological properties, and in many cases the micropellets can subsequently be utilized as building blocks to assemble complex macrotissues. Generally, micropellets are formed from cells alone, however when replicating matrix-rich tissues such as cartilage it would be ideal if matrix or biomaterials supplements could be incorporated directly into the micropellet during the manufacturing process. Herein we describe a method to efficiently incorporate donor cartilage matrix into tissue engineered cartilage micropellets. We lyophilized bovine cartilage matrix, and then shattered it into microscopic pieces having average dimensions < 10 μm diameter; we termed this microscopic donor matrix “cartilage dust (CD)”. Using a microwell platform, we show that ~0.83 μg CD can be rapidly and efficiently incorporated into single multicellular aggregates formed from 180 bone marrow mesenchymal stem/stromal cells (MSC) each. The microwell platform enabled the rapid manufacture of thousands of replica composite micropellets, with each micropellet having a material/CD core and a cellular surface. This micropellet organization enabled the rapid bulking up of the micropellet core matrix content, and left an adhesive cellular outer surface. This morphological organization enabled the ready assembly of the composite micropellets into macroscopic tissues. Generically, this is a versatile method that enables the rapid and uniform integration of biomaterials into multicellular micropellets that can then be used as tissue building blocks. In this study, the addition of CD resulted in an approximate 8-fold volume increase in the micropellets, with the donor matrix functioning to contribute to an increase in total cartilage matrix content. Composite micropellets were readily assembled into macroscopic cartilage tissues; the incorporation of CD enhanced tissue size and matrix content, but did not enhance chondrogenic gene expression. PMID:26020956

Communication: Electron ionization of DNA bases.

PubMed

Rahman, M A; Krishnakumar, E

2016-04-28

No reliable experimental data exist for the partial and total electron ionization cross sections for DNA bases, which are very crucial for modeling radiation damage in genetic material of living cell. We have measured a complete set of absolute partial electron ionization cross sections up to 500 eV for DNA bases for the first time by using the relative flow technique. These partial cross sections are summed to obtain total ion cross sections for all the four bases and are compared with the existing theoretical calculations and the only set of measured absolute cross sections. Our measurements clearly resolve the existing discrepancy between the theoretical and experimental results, thereby providing for the first time reliable numbers for partial and total ion cross sections for these molecules. The results on fragmentation analysis of adenine supports the theory of its formation in space.

Photoionization and Photofragmentation of the Endohedral Xe C60+ Molecular Ion

NASA Astrophysics Data System (ADS)

Aryal, Nagendra Bahadur

An experimental study of photoionization and fragmentation of the Xe C 60+ endohedral molecular ion is presented in the photon energy range of the well-known Xe 4d giant resonance, and evidence of redistribution of the Xe 4d oscillator strength in photon energy due to multipath interference is reported. Experiments were conducted at undulator beamline 10.0.1 of the Advanced Light Source (ALS) using the merged-beams technique. Prior to these measurements, macroscopic samples containing endohedral Xe C60 were prepared using a setup developed at the ALS. Endohedral Xe C60 yields as high as 2.5x10 -4 were synthesized and a pure Xe C60+ ion beam current of up to 5.5 pA was obtained for the merged-beams experiments. Cross sections were measured in the photon energy range 60 - 150 eV in 0.5 eV steps for single, double, and triple photoionization of endohedral Xe C 60+ accompanied by the loss of n pairs of carbon atoms yielding Xe C60-2n2+ (n = 0, 1), Xe C60-2n 3+ (n = 0, 1, 2, 3), and Xe C584+ photoion products. Reference absolute cross-section measurements were made for empty C60+ for the corresponding reaction channels. The spectroscopic measurements with Xe C60+ were placed onto an absolute scale by normalization to the reference cross sections for C60+ in ranges of photon energies where the Xe 4d contributions were negligible. Results for single photoionization and fragmentation of Xe C60+ show no evidence of the presence of the caged Xe atom. The measurements of double and triple photoionization with fragmentation of Xe C60+ exhibit prominent signatures of the Xe 4d resonance and together account for 6.6 +/- 1.5 of the total Xe 4d oscillator strength of 10. Compared to that for a free Xe atom, the Xe oscillator strength in Xe C60+ is redistributed in photon energy due to multipath interference of outgoing Xe 4d photoelectron waves that may be transmitted or reflected by the spherical C60+ molecular cage, yielding so-called confinement resonances. The experimental data are compared with numerous theoretical predictions for this novel single-molecule photoelectron interferometer system. The comparison indicates that the interference structure is sensitive to the geometry of the molecular cage.

Identification of macroscopic sarcocysts of Sarcocystis cameli from camels (Camelus dromedarius) in Iraq

USDA-ARS?s Scientific Manuscript database

There is considerable confusion concerning the identity of macroscopic Sarcocystis species in camels. Currently two species: Sarcocystis cameli, and S. ippeni are recognized from one humped camel (Camelus dromedarius), and sarcocysts of both species are microscopic. Here, we report identity of macro...

LEAD SORPTION ON RUTHENIUM OXIDE: A MACROSCOPIC AND SPECTROSCOPIC STUDY

EPA Science Inventory

The sorption and desorption of Pb on RuO2 xH2O were examined kinetically and thermodynamically via spectroscopic and macroscopic investigations. X-ray absorption spectroscopy (XAS) was employed to determine the sorption mechanism with regard to identity of nearest atomic neighbo...

On the origin and elimination of macroscopic defects in MBE films

NASA Astrophysics Data System (ADS)

Wood, C. E. C.; Rathbun, L.; Ohno, H.; DeSimone, D.

1981-02-01

Spitting of group III metal droplets from Knudsen type effusion cells has been found culpable for a genre of problematical macroscopic surface topographical defects observed in the growth of semiconductor films by molecular beam epitaxy. Successful precautions are described which virtually eliminate the problem.

Mono-Heteromeric Configurations of Gap Junction Channels Formed by Connexin43 and Connexin45 Reduce Unitary Conductance and Determine both Voltage Gating and Metabolic Flux Asymmetry

PubMed Central

Zhong, Guoqiang; Akoum, Nazem; Appadurai, Daniel A.; Hayrapetyan, Volodya; Ahmed, Osman; Martinez, Agustin D.; Beyer, Eric C.; Moreno, Alonso P.

2017-01-01

In cardiac tissues, the expression of multiple connexins (Cx40, Cx43, Cx45, and Cx30.2) is a requirement for proper development and function. Gap junctions formed by these connexins have distinct permeability and gating mechanisms. Since a single cell can express more than one connexin isoform, the formation of hetero-multimeric gap junction channels provides a tissue with an enormous repertoire of combinations to modulate intercellular communication. To study further the perm-selectivity and gating properties of channels containing Cx43 and Cx45, we studied two monoheteromeric combinations in which a HeLa cell co-transfected with Cx43 and Cx45 was paired with a cell expressing only one of these connexins. Macroscopic measurements of total conductance between cell pairs indicated a drastic reduction in total conductance for mono-heteromeric channels. In terms of Vj dependent gating, Cx43 homomeric connexons facing heteromeric connexons only responded weakly to voltage negativity. Cx45 homomeric connexons exhibited no change in Vj gating when facing heteromeric connexons. The distributions of unitary conductances (γj) for both mono-heteromeric channels were smaller than predicted, and both showed low permeability to the fluorescent dyes Lucifer yellow and Rhodamine123. For both mono-heteromeric channels, we observed flux asymmetry regardless of dye charge: flux was higher in the direction of the heteromeric connexon for MhetCx45 and in the direction of the homomeric Cx43 connexon for MhetCx43. Thus, our data suggest that co-expression of Cx45 and Cx43 induces the formation of heteromeric connexons with greatly reduced permeability and unitary conductance. Furthermore, it increases the asymmetry for voltage gating for opposing connexons, and it favors asymmetric flux of molecules across the junction that depends primarily on the size (not the charge) of the crossing molecules. PMID:28611680

Cystic echinococcosis amongst small ruminants and humans in central Ethiopia.

PubMed

Assefa, Habtamu; Mulate, Belay; Nazir, Shahid; Alemayehu, Alula

2015-08-21

This study was conducted to determine the prevalence of cystic echinococcosis (CE) in small ruminants and humans in Addis Ababa, central Ethiopia. A cross-sectional study involving systematic random sampling was conducted to estimate the prevalence of CE in 512 small ruminants (262 sheep and 250 goats) slaughtered at Addis Ababa Abattoir Enterprise between October 2011 and March 2012. Hydatid cysts were identified macroscopically during postmortem examination and their fertility and viability were determined. CE was observed in 21 (8.02%) sheep and 17 (6.80%) goats. In sheep 13 (4.96%) of the lungs, 10 (3.81%) livers and 1 (0.381%) heart were found to be infected with hydatid cysts. Involvement of lung and liver in goats was found to be 10 (4.0%) and 8 (3.2%) respectively, with no cysts recorded in the heart. Of the total of 77 and 47 cysts encountered in sheep and goats, 33 (42.85%) and 15 (31.91%) respectively were fertile. Viability of protoscoleces from fertile cysts in sheep (29 [87.87%]) was higher than in goats (6 [40.0%]). For humans, retrospective analysis covering five years of case reports at two major hospitals in Addis Ababa between January 2008 and December 2012 showed that of the total of 25 840 patients admitted for ultrasound examination, 27 CE cases were registered, a prevalence of 0.1% and mean annual incidence rate of approximately 0.18 cases per 100 000 population. Liver was the major organ affected in humans (81.5% in affected patients) followed by spleen (11.1%) and kidney (7.4%). Logistic regression analysis showed that prevalence of CE varied significantly in relation to host age in the small ruminants (OR = 3.93, P < 0.05) as well as in humans (95% CI, R = 4.8). This epidemiological study confirms the importance of CE in small ruminants and humans in central Ethiopia, emphasising the need for integrated approaches to controlling this neglected preventable disease.

Mono-Heteromeric Configurations of Gap Junction Channels Formed by Connexin43 and Connexin45 Reduce Unitary Conductance and Determine both Voltage Gating and Metabolic Flux Asymmetry.

PubMed

Zhong, Guoqiang; Akoum, Nazem; Appadurai, Daniel A; Hayrapetyan, Volodya; Ahmed, Osman; Martinez, Agustin D; Beyer, Eric C; Moreno, Alonso P

2017-01-01

In cardiac tissues, the expression of multiple connexins (Cx40, Cx43, Cx45, and Cx30.2) is a requirement for proper development and function. Gap junctions formed by these connexins have distinct permeability and gating mechanisms. Since a single cell can express more than one connexin isoform, the formation of hetero-multimeric gap junction channels provides a tissue with an enormous repertoire of combinations to modulate intercellular communication. To study further the perm-selectivity and gating properties of channels containing Cx43 and Cx45, we studied two monoheteromeric combinations in which a HeLa cell co-transfected with Cx43 and Cx45 was paired with a cell expressing only one of these connexins. Macroscopic measurements of total conductance between cell pairs indicated a drastic reduction in total conductance for mono-heteromeric channels. In terms of Vj dependent gating, Cx43 homomeric connexons facing heteromeric connexons only responded weakly to voltage negativity. Cx45 homomeric connexons exhibited no change in Vj gating when facing heteromeric connexons. The distributions of unitary conductances (γj) for both mono-heteromeric channels were smaller than predicted, and both showed low permeability to the fluorescent dyes Lucifer yellow and Rhodamine123. For both mono-heteromeric channels, we observed flux asymmetry regardless of dye charge: flux was higher in the direction of the heteromeric connexon for MhetCx45 and in the direction of the homomeric Cx43 connexon for MhetCx43. Thus, our data suggest that co-expression of Cx45 and Cx43 induces the formation of heteromeric connexons with greatly reduced permeability and unitary conductance. Furthermore, it increases the asymmetry for voltage gating for opposing connexons, and it favors asymmetric flux of molecules across the junction that depends primarily on the size (not the charge) of the crossing molecules.

[Microscopic extensions of head and neck squamous cell carcinomas: impact for clinical target volume definition].

PubMed

Fleury, B; Thariat, J; Barnoud, R; Buiret, G; Lebreton, F; Bancel, B; Poupart, M; Devouassoux-Shisheboran, M

2014-11-01

To assess microscopic extensions of head and neck squamous cell carcinomas aiming at a proposal for target volumes of radiation therapy. Surgical specimens were prospectively analysed macroscopically and microscopically. Tumour borders were identified per macroscopic visual examination and inked on stained slides. Then microscopic implants (perineural or lymphatic involvement, or in situ carcinomas) were looked for with an optic microscope in the macroscopic healthy tissue surrounding the tumour. The maximal length from tumour border was correlated with the maximal length of macroscopically healthy tissues assessable. Twenty-one specimens were analysed and 12 were locally advanced tumours. Mean and median maximal microscopic extensions were 2.9 and 1.0mm (0-15mm), respectively. The 90th and 95th percentiles were 5 and 11mm, respectively. The ratio between healthy tissue length and maximal microscopic tumour extension was 10%. No correlation was found with tumour grade or volume. The presence of microscopic tumour was unlikely after 5mm from macroscopic tumour (≤5% of patients in this series) but should be assessed along with other histoclinical factors and particularities of tumour behaviour by anatomic site. A rigorous terminology should authorize a relevant appreciation of local risk of recurrence, particularly in adjuvant setting or for clinical target volume definition. Larger and more homogenous confirmatory series are needed. Copyright © 2014. Published by Elsevier SAS.

Induction log responses to layered, dipping, and anisotropic formations: Induction log shoulder-bed corrections to anisotropic formations and the effect of shale anisotropy in thinly laminated sand/shale sequences

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hagiwara, Teruhiko

1996-12-31

Induction log responses to layered, dipping, and anisotropic formations are examined analytically. The analytical model is especially helpful in understanding induction log responses to thinly laminated binary formations, such as sand/shale sequences, that exhibit macroscopically anisotropic: resistivity. Two applications of the analytical model are discussed. In one application we examine special induction log shoulder-bed corrections for use when thin anisotropic beds are encountered. It is known that thinly laminated sand/shale sequences act as macroscopically anisotropic: formations. Hydrocarbon-bearing formations also act as macroscopically anisotropic formations when they consist of alternating layers of different grain-size distributions. When such formations are thick, inductionmore » logs accurately read the macroscopic conductivity, from which the hydrocarbon saturation in the formations can be computed. When the laminated formations are not thick, proper shoulder-bed corrections (or thin-bed corrections) should be applied to obtain the true macroscopic formation conductivity and to estimate the hydrocarbon saturation more accurately. The analytical model is used to calculate the thin-bed effect and to evaluate the shoulder-bed corrections. We will show that the formation resistivity and hence the hydrocarbon saturation are greatly overestimated when the anisotropy effect is not accounted for and conventional shoulder-bed corrections are applied to the log responses from such laminated formations.« less

The use of histology in 638 coronial post-mortem examinations of adults: an audit.

PubMed

Langlois, Neil E I

2006-10-01

An audit was performed to determine the effectiveness of histological sampling of forensic post-mortem cases based on a review of three years' data, which comprised 638 adult autopsy cases. During the study period organs and tissues that appeared macroscopically normal and abnormal were extensively sampled. Histology was regarded as in some way contributory (providing, altering or confirming a cause of death) 53% of the time. The use of histology provided the cause of death in 49 (24%) of the 203 cases not given a cause of death after the completion of the macroscopic examination. When an interim cause of death had been supplied following the completion of the gross examination it was changed in 4.8% of cases, but there were no changes of the manner of death. The majority of the histological diagnoses or discrepancies involved the lungs and the heart. All diagnoses relevant to determining the cause of death would have been made if samples had been taken only from the left ventricle, right ventricle, coronary arteries, lungs, kidneys and brain with any tissue or organ that appeared abnormal macroscopically. A macroscopically identified abnormality that appeared to have been responsible for death was not sampled in 20 cases; consequently, more attention will be paid to sampling macroscopically abnormal tissues. As a result of this audit histology sampling practice has been revised and will be re-audited in the future.

Measurement of the Total Cross Section of Uranium-Uranium Collisions at √{sNN} = 192 . 8 GeV

NASA Astrophysics Data System (ADS)

Baltz, A. J.; Fischer, W.; Blaskiewicz, M.; Gassner, D.; Drees, K. A.; Luo, Y.; Minty, M.; Thieberger, P.; Wilinski, M.; Pshenichnov, I. A.

2014-03-01

The total cross section of Uranium-Uranium at √{sNN} = 192 . 8 GeV has been measured to be 515 +/-13stat +/-22sys barn, which agrees with the calculated theoretical value of 487.3 barn within experimental error. That this total cross section is more than an order of magnitude larger than the geometric ion-ion cross section is primarily due to Bound-Free Pair Production (BFPP) and Electro-Magnetic Dissociation (EMD). Nearly all beam losses were due to geometric, BFPP and EMD collisions. This allowed the determination of the total cross section from the measured beam loss rates and luminosity. The beam loss rate is calculated from a time-dependent measurement of the total beam intensity. The luminosity is measured via the detection of neutron pairs in time-coincidence in the Zero Degree Calorimeters. Apart from a general interest in verifying the calculations experimentally, an accurate prediction of the losses created in the heavy ion collisions is of practical interest for the LHC, where collision products have the potential to quench cryogenically cooled magnets.

Blessing and curse of chaos in numerical turbulence simulations

NASA Astrophysics Data System (ADS)

Lee, Jon

1994-03-01

Because of the trajectory instability, time reversal is not possible beyond a certain evolution time and hence the time irreversibility prevails under the finite-accuracy trajectory computation. This therefore provides a practical reconciliation of the dynamic reversibility and macroscopic irreversibility (blessing of chaos). On the other hand, the trajectory instability is also responsible for a limited evolution time, so that finite-accuracy computation would yield a pseudo-orbit which is totally unrelated to the true trajectory (curse of chaos). For the inviscid 2D flow, however, we can accurately compute the long- time average of flow quantities with a pseudo-orbit by invoking the ergodic theorem.

Measuring the Newtonian constant of gravitation G with an atomic interferometer

PubMed Central

Prevedelli, M.; Cacciapuoti, L.; Rosi, G.; Sorrentino, F.; Tino, G. M.

2014-01-01

We have recently completed a measurement of the Newtonian constant of gravitation G using atomic interferometry. Our result is G=6.67191(77)(62)×10−11 m3 kg−1 s−2 where the numbers in parenthesis are the type A and type B standard uncertainties, respectively. An evaluation of the measurement uncertainty is presented and the perspectives for improvement are discussed. Our result is approaching the precision of experiments based on macroscopic sensing masses showing that the next generation of atomic gradiometers could reach a total relative uncertainty in the 10 parts per million range. PMID:25202001

Macroscopic and stereomicroscopic comparison of hacking trauma of bones before and after carbonization.

PubMed

Alunni, Véronique; Nogueira, Luísa; Quatrehomme, Gérald

2018-03-01

This experimental study examined lesions produced by a hatchet on pig femurs before and after carbonization. A total of 30 lesions were produced and analyzed using stereomicroscopy and then reexamined after carbonization. Not only was the sharp-blunt mechanism of the hacking trauma (V-shape, regularity of one edge, irregularity of the other edge, upraising, lateral pushing back, fossae dug laterally to the edge) still recognizable after carbonization; in some instances, the carbonization actually enhanced the features observed. Carbonization also did not significantly alter the measurements of the lesions. Carbonization tends to alter the structure of the bone especially in areas weakened by the blunt trauma.

PolyMEMS Actuator: A Polymer-Based Microelectromechanical (MEMS) Actuator with Macroscopic Action

DTIC Science & Technology

2002-09-01

On the right, a gold reinforcement layer has been added on top of the Al, creating a more robust bond. These held up well to handling and use...value back into the total energy, and finally set ∂UT/∂δ=0, with the result V d EtF oext 2/1 2 3 4)1(4 3       − −= εε ν π . (26) 25...0.5-1 µm gold layer above the bond pad. The thicker film resists peeling, has very low contact resistance, and can be soldered. The second

Effects of Increased Loading on In Vivo Tendon Properties: A Systematic Review

PubMed Central

WIESINGER, HANS-PETER; KÖSTERS, ALEXANDER; MÜLLER, ERICH; SEYNNES, OLIVIER R.

2015-01-01

ABSTRACT Introduction In vivo measurements have been used in the past two decades to investigate the effects of increased loading on tendon properties, yet the current understanding of tendon macroscopic changes to training is rather fragmented, limited to reports of tendon stiffening, supported by changes in material properties and/or tendon hypertrophy. The main aim of this review was to analyze the existing literature to gain further insights into tendon adaptations by extracting patterns of dose-response and time-course. Methods PubMed/Medline, SPORTDiscus, and Google Scholar databases were searched for studies examining the effect of training on material, mechanical, and morphological properties via longitudinal or cross-sectional designs. Results Thirty-five of 6440 peer-reviewed articles met the inclusion criteria. The key findings were i) the confirmation of a nearly systematic adaptation of tendon tissue to training, ii) the important variability in the observed changes in tendon properties between and within studies, and iii) the absence of a consistent incremental pattern regarding the dose-response or the time-course relation of tendon adaptation within the first months of training. However, long-term (years) training was associated with a larger tendon cross-sectional area, without any evidence of differences in material properties. Our analysis also highlighted several gaps in the existing literature, which may be addressed in future research. Conclusions In line with some cross-species observations about tendon design, tendon cross-sectional area allegedly constitutes the ultimate adjusting parameter to increased loading. We propose here a theoretical model placing tendon hypertrophy and adjustments in material properties as parts of the same adaptive continuum. PMID:25563908

SORPTION OF LEAD ON A HIGH AFFINITY OXIDE: MACROSCOPIC AND MICROSCOPIC STUDIES

EPA Science Inventory

Sorption of lead (Pb) was investigated on an innovative metal oxide compound using macroscopic and microscopic techniques. The objective of this study was to elucidate the sorption mechanism of Pb on the high-affinity engineered oxide with time at pH 6 employing batch methods an...

SORPTION OF LEAD ON A HIGH AFFINITY OXIDE: MACROSCOPIC AND MICROSCOPIC STUDIES (ABSTRACT)

EPA Science Inventory

Sorption of lead (Pb) was investigated on an innovative metal oxide compound using macroscopic and microscopic techniques. The objective of this study was to elucidate the sorption mechanism of Pb on the high-affinity engineered oxide with time at pH 6 employing batch methods an...

Macroscopic to Microscopic Scales of Particulate Dosimetry: From Source to Fate in the Body

EPA Science Inventory

Additional perspective with regards to particle dosimetry is achieved by exploring dosimetry across a range of scales from macroscopic to microscopic in scope. Typically, one thinks of dosimetry as what happens when a particle is inhaled, where it is deposited, and how it is clea...

Liposarcoma in clownfish, Amphiprion ocellaris Cuvier, produced in indoor aquaculture.

PubMed

Sharon, G; Benharroch, D; Kachko, L; Reis-Hevlin, N; Zilberg, D

2015-06-01

Clownfish, Amphiprion ocellaris Cuvier, produced and grown in an experimental indoor aquaculture facility, presented with lipomatous tumours. A total of 14 affected fish were examined. Based on the total number of fish at the aquaculture facility at the time of outbreak of this pathology, the scope of the incident is estimated to be 1 of 300 fish. The tumours were characterized by the presence of mature adipocytes of variable sizes, lipoblasts and by an invasive behaviour, which affected internal organs, muscle, central nervous system and, in one case, an eye. Detailed macroscopic and histopathological features are presented. The suggested diagnosis is that of a well-differentiated liposarcoma, a diagnosis so far never applied to fish. The limited outbreak of the neoplasm lasted a few months in 2011 and did not recur. Possible factors leading to this phenomenon, notably the metastasis, are discussed. © 2014 John Wiley & Sons Ltd.

Communication: Electron ionization of DNA bases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rahman, M. A.; Krishnakumar, E., E-mail: ekkumar@tifr.res.in

2016-04-28

No reliable experimental data exist for the partial and total electron ionization cross sections for DNA bases, which are very crucial for modeling radiation damage in genetic material of living cell. We have measured a complete set of absolute partial electron ionization cross sections up to 500 eV for DNA bases for the first time by using the relative flow technique. These partial cross sections are summed to obtain total ion cross sections for all the four bases and are compared with the existing theoretical calculations and the only set of measured absolute cross sections. Our measurements clearly resolve themore » existing discrepancy between the theoretical and experimental results, thereby providing for the first time reliable numbers for partial and total ion cross sections for these molecules. The results on fragmentation analysis of adenine supports the theory of its formation in space.« less

The role of endogenous and exogenous mechanisms in the formation of R&D networks

NASA Astrophysics Data System (ADS)

Tomasello, Mario V.; Perra, Nicola; Tessone, Claudio J.; Karsai, Márton; Schweitzer, Frank

2014-07-01

We develop an agent-based model of strategic link formation in Research and Development (R&D) networks. Empirical evidence has shown that the growth of these networks is driven by mechanisms which are both endogenous to the system (that is, depending on existing alliances patterns) and exogenous (that is, driven by an exploratory search for newcomer firms). Extant research to date has not investigated both mechanisms simultaneously in a comparative manner. To overcome this limitation, we develop a general modeling framework to shed light on the relative importance of these two mechanisms. We test our model against a comprehensive dataset, listing cross-country and cross-sectoral R&D alliances from 1984 to 2009. Our results show that by fitting only three macroscopic properties of the network topology, this framework is able to reproduce a number of micro-level measures, including the distributions of degree, local clustering, path length and component size, and the emergence of network clusters. Furthermore, by estimating the link probabilities towards newcomers and established firms from the data, we find that endogenous mechanisms are predominant over the exogenous ones in the network formation, thus quantifying the importance of existing structures in selecting partner firms.

Cellular modelling of secondary radial growth in conifer trees: application to Pinus radiata (D. Don).

PubMed

Forest, Loïc; Demongeot, Jacques; Demongeota, Jacques

2006-05-01

The radial growth of conifer trees proceeds from the dynamics of a merismatic tissue called vascular cambium or cambium. Cambium is a thin layer of active proliferating cells. The purpose of this paper was to model the main characteristics of cambial activity and its consecutive radial growth. Cell growth is under the control of the auxin hormone indole-3-acetic. The model is composed of a discrete part, which accounts for cellular proliferation, and a continuous part involving the transport of auxin. Cambium is modeled in a two-dimensional cross-section by a cellular automaton that describes the set of all its constitutive cells. Proliferation is defined as growth and division of cambial cells under neighbouring constraints, which can eliminate some cells from the cambium. The cell-growth rate is determined from auxin concentration, calculated with the continuous model. We studied the integration of each elementary cambial cell activity into the global coherent movement of macroscopic morphogenesis. Cases of normal and abnormal growth of Pinus radiata (D. Don) are modelled. Abnormal growth includes deformed trees where gravity influences auxin transport, producing heterogeneous radial growth. Cross-sectional microscopic views are also provided to validate the model's hypothesis and results.

Transient viscous response of the human cornea probed with the Surface Force Apparatus.

PubMed

Zappone, Bruno; Patil, Navinkumar J; Lombardo, Marco; Lombardo, Giuseppe

2018-01-01

Knowledge of the biomechanical properties of the human cornea is crucial for understanding the development of corneal diseases and impact of surgical treatments (e.g., corneal laser surgery, corneal cross-linking). Using a Surface Force Apparatus we investigated the transient viscous response of the anterior cornea from donor human eyes compressed between macroscopic crossed cylinders. Corneal biomechanics was analyzed using linear viscoelastic theory and interpreted in the framework of a biphasic model of soft hydrated porous tissues, including a significant contribution from the pressurization and viscous flow of fluid within the corneal tissue. Time-resolved measurements of tissue deformation and careful determination of the relaxation time provided an elastic modulus in the range between 0.17 and 1.43 MPa, and fluid permeability of the order of 10-13 m4/(N∙s). The permeability decreased as the deformation was increased above a strain level of about 10%, indicating that the interstitial space between fibrils of the corneal stromal matrix was reduced under the effect of strong compression. This effect may play a major role in determining the observed rate-dependent non-linear stress-strain response of the anterior cornea, which underlies the shape and optical properties of the tissue.

Angular distributions for H- formation in single collisions of H+ on Mg

NASA Astrophysics Data System (ADS)

Alvarez, I.; Cisneros, C.; Russek, A.

1982-07-01

Absolute differential cross sections have been measured for H- formation in single collisions of H+ on Mg in the energy range from 0.5 to 5.0 keV. Total cross sections, obtained by direct integration of these differential cross sections, are in good agreement with earlier total-cross-section measurements of Morgan and Eriksen in the energy range common to the two experiments and are in good agreement with the calculated total cross sections of Olson and Liu. The differential cross sections are strongly peaked in the forward direction. The functional form and scaling properties of this forward peak strongly indicate that it is a glory maximum, which occurs when the classical deflection function changes over from attractive to repulsive at some finite impact parameter. The differential cross sections from 1.0 to 5.0 keV show no other structure, but below 1.0 keV a τ-dependent structure is observed which becomes more pronounced as the collision energy decreases. 1982 The American Physical Society.

Contact Dependence and Velocity Crossover in Friction between Microscopic Solid/Solid Contacts.

PubMed

McGraw, Joshua D; Niguès, Antoine; Chennevière, Alexis; Siria, Alessandro

2017-10-11

Friction at the nanoscale differs markedly from that between surfaces of macroscopic extent. Characteristically, the velocity dependence of friction between apparent solid/solid contacts can strongly deviate from the classically assumed velocity independence. Here, we show that a nondestructive friction between solid tips with radius on the scale of hundreds of nanometers and solid hydrophobic self-assembled monolayers has a strong velocity dependence. Specifically, using laterally oscillating quartz tuning forks, we observe a linear scaling in the velocity at the lowest accessed velocities, typically hundreds of micrometers per second, crossing over into a logarithmic velocity dependence. This crossover is consistent with a general multicontact friction model that includes thermally activated breaking of the contacts at subnanometric elongation. We find as well a strong dependence of the friction on the dimensions of the frictional probe.

Spontaneous multicentric soft tissue sarcoma in a captive African pygmy hedgehog (Atelerix albiventris): case report and literature review

PubMed Central

DÍAZ-DELGADO, Josué; POOL, Roy; HOPPES, Sharman; CEREZO, Argine; QUESADA-CANALES, Óscar; STOICA, George

2017-01-01

This report describes the clinical, macroscopic, histopathological and immunohistochemical features of a spontaneous multicentric extraskeletal sarcoma in an adult male African hedgehog (Atelerix albiventris). It also provides a succinct up-to-date review on neoplasia in this species. On autopsy examination, main gross findings included a moderately demarcated cranial mass and a multilobulated, caudal intra-abdominal mass. The cranial mass had perforated the underlying temporal and occipital bones and had extended into the cranial vault and was compressing the surface of the cerebellum and cerebrum. Histologic, histochemical and immunohistochemical analyses supported a diagnosis of multicentric poorly differentiated spindle cell sarcoma with fibrosarcomatous, storiform and myxoid foci. The high incidence of neoplasia and cross similarities renders the African hedgehog a suitable species for comparative pathology studies. PMID:28331115

Total Electron-Impact Ionization Cross-Sections of CFx and NFx (x = 1 - 3)

NASA Technical Reports Server (NTRS)

Huo, Winifred M.; Tarnovsky, Vladimir; Becker, Kurt H.; Kwak, Dochan (Technical Monitor)

2001-01-01

The discrepancy between experimental and theoretical total electron-impact ionization cross sections for a group of fluorides, CFx, and NFx, (x = 1 - 3), is attributed to the inadequacies in previous theoretical models. Cross-sections calculated using a recently developed siBED (simulation Binary-Encounter-Dipole) model that takes into account the shielding of the long-range dipole potential between the scattering electron and target are in agreement with experimentation. The present study also carefully reanalyzed the previously reported experimental data to account for the possibility of incomplete collection of fragment ions and the presence of ion-pair formation channels. For NF3, our experimental and theoretical cross-sections compare well with the total ionization cross-sections recently reported by Haaland et al. in the region below dication formation.

Introduction to the physics of the total cross section at LHC. A review of data and models

NASA Astrophysics Data System (ADS)

Pancheri, Giulia; Srivastava, Yogendra N.

2017-03-01

This review describes the development of the physics of hadronic cross sections up to recent LHC results and cosmic ray experiments. We present here a comprehensive review - written with a historical perspective - about total cross sections from medium to the highest energies explored experimentally and studied through a variety of methods and theoretical models for over 60 years. We begin by recalling the analytic properties of the elastic amplitude and the theorems about the asymptotic behavior of the total cross section. A discussion of how proton-proton cross sections are extracted from cosmic rays at higher than accelerator energies and help the study of these asymptotic limits, is presented. This is followed by a description of the advent of particle colliders, through which high energies and unmatched experimental precisions have been attained. Thus the measured hadronic elastic and total cross sections have become crucial instruments to probe the so called soft part of QCD physics, where quarks and gluons are confined, and have led to test and refine Regge behavior and a number of diffractive models. As the c.m. energy increases, the total cross section also probes the transition into hard scattering describable with perturbative QCD, the so-called mini-jet region. Further tests are provided by cross section measurements of γ p, γ ^* p and γ ^* γ ^* for models based on vector meson dominance, scaling limits of virtual photons at high Q^2 and the BFKL formalism. Models interpolating from virtual to real photons are also tested.

Renal cell carcinoma containing abundant non-calcified fat.

PubMed

Wasser, Elliot J; Shyn, Paul B; Riveros-Angel, Marcela; Sadow, Cheryl A; Steele, Graeme S; Silverman, Stuart G

2013-06-01

Renal masses found to contain macroscopic fatty elements on CT or MRI imaging can generally be classified as benign angiomyolipomas. Rarely, renal cell carcinomas may also contain evidence of macroscopic fat. When true adipocytic elements are present, this is generally due to a process of osseous metaplasia in which both fat cells and calcification are co-localized within the mass. We present a patient with a large papillary renal cell carcinoma containing abundant fat with sparse, punctate calcification remote from the fatty elements on imaging. This report highlights the need for radiologists to maintain caution when diagnosing renal angiomyolipomas on the basis of macroscopic fat and reviews the current literature on fat-containing renal masses.

Chiral Domain Structure in Superfluid 3He-A Studied by Magnetic Resonance Imaging

NASA Astrophysics Data System (ADS)

Kasai, J.; Okamoto, Y.; Nishioka, K.; Takagi, T.; Sasaki, Y.

2018-05-01

The existence of a spatially varying texture in superfluid 3He is a direct manifestation of the complex macroscopic wave function. The real space shape of the texture, namely, a macroscopic wave function, has been studied extensively with the help of theoretical modeling but has never been directly observed experimentally with spatial resolution. We have succeeded in visualizing the texture by a specialized magnetic resonance imaging. With this new technology, we have discovered that the macroscopic chiral domains, of which sizes are as large as 1 mm, and corresponding chiral domain walls exist rather stably in 3He - A film at temperatures far below the transition temperature.

Macroscopic Modeling of In Vivo Drug Transport in Electroporated Tissue.

PubMed

Boyd, Bradley; Becker, Sid

2016-03-01

This study develops a macroscopic model of mass transport in electroporated biological tissue in order to predict the cellular drug uptake. The change in the macroscopic mass transport coefficient is related to the increase in electrical conductivity resulting from the applied electric field. Additionally, the model considers the influences of both irreversible electroporation (IRE) and the transient resealing of the cell membrane associated with reversible electroporation. Two case studies are conducted to illustrate the applicability of this model by comparing transport associated with two electrode arrangements: side-by-side arrangement and the clamp arrangement. The results show increased drug transmission to viable cells is possible using the clamp arrangement due to the more uniform electric field.

Probabilistic Metrology Attains Macroscopic Cloning of Quantum Clocks

NASA Astrophysics Data System (ADS)

Gendra, B.; Calsamiglia, J.; Muñoz-Tapia, R.; Bagan, E.; Chiribella, G.

2014-12-01

It has recently been shown that probabilistic protocols based on postselection boost the performances of the replication of quantum clocks and phase estimation. Here we demonstrate that the improvements in these two tasks have to match exactly in the macroscopic limit where the number of clones grows to infinity, preserving the equivalence between asymptotic cloning and state estimation for arbitrary values of the success probability. Remarkably, the cloning fidelity depends critically on the number of rationally independent eigenvalues of the clock Hamiltonian. We also prove that probabilistic metrology can simulate cloning in the macroscopic limit for arbitrary sets of states when the performance of the simulation is measured by testing small groups of clones.

Metabolic design of macroscopic bioreaction models: application to Chinese hamster ovary cells.

PubMed

Provost, A; Bastin, G; Agathos, S N; Schneider, Y-J

2006-12-01

The aim of this paper is to present a systematic methodology to design macroscopic bioreaction models for cell cultures based upon metabolic networks. The cell culture is seen as a succession of phases. During each phase, a metabolic network represents the set of reactions occurring in the cell. Then, through the use of the elementary flux modes, these metabolic networks are used to derive macroscopic bioreactions linking the extracellular substrates and products. On this basis, as many separate models are obtained as there are phases. Then, a complete model is obtained by smoothly switching from model to model. This is illustrated with batch cultures of Chinese hamster ovary cells.

Redkinian Biota of Macroscopic Fossils from the Northwestern East European Platform (South Ladoga Region)

NASA Astrophysics Data System (ADS)

Golubkova, E. Yu.; Kushim, E. A.; Kuznetsov, A. B.; Yanovskii, A. S.; Maslov, A. V.; Shvedov, S. D.; Plotkina, Yu. V.

2018-03-01

The stratigraphic distribution of microfossils and macroscopic fossil biota in Vendian deposits of the South Ladoga region (northwestern East European Platform) is analyzed. In the sequence of the Shotkusa- 1 well, three taxonomically heterogeneous microfossil assemblages are distinguished: two of them refer to the Redkinian age (Starorusskaya Fm.) and one to the Kotlinian age (Vasileostrovskaya Fm.). Deposits of the Starorusskaya Fm. contain Redkinian biota of macroscopic fossils, of which the most characteristic representatives are Chuaria circularis, Doushantuophyton lineare, Morania zinkovi, Orbisiana simplex, and Redkinia spinosa. These new findings expand the paleontological characteristics of Upper Vendian deposits, also providing additional criteria for distinguishing the Redkinian horizon in the northwestern East European Platform.

Flux dynamics and magnetovoltage measurements in a macroscopic cylindrical hole drilled in BSCCO

NASA Astrophysics Data System (ADS)

Yetiş, H.; Altinkok, A.; Olutaş, M.; Kiliç, A.; Kiliç, K.

2007-10-01

Slow transport relaxation measurements (V-t curves) and magnetovoltage measurements (V-H curves) were carried out in a polycrystalline sample of Bi1.7Pb0.3Sr2Ca2Cu3Ox (BSCCO) with a macroscopic cylindrically drilled hole (CH). The time evolution of quenched state in V-t curves was interpreted in terms of enhancement of the superconducting order parameter and the relaxation of moving entity. Upon cycling of the external magnetic field with different sweep rates, unusual counter clockwise hysteresis effects and asymmetry in V-H curves are observed in BSCCO sample with CH, which can also be correlated to the trapping of the macroscopic flux bundles in CH.

Positron total scattering cross-sections for alkali atoms

NASA Astrophysics Data System (ADS)

Sinha, Nidhi; Singh, Suvam; Antony, Bobby

2018-01-01

Positron-impact total scattering cross-sections for Li, Na, K, Rb, Cs and Fr atoms are calculated in the energy range from 5-5000 eV employing modified spherical complex optical potential formalism. The main aim of this work is to apply this formalism to the less studied positron-target collision systems. The results are compared with previous theoretical and experimental data, wherever available. In general, the present data show overall agreement and consistency with other results. Furthermore, we have done a comparative study of the results to investigate the effect of atomic size on the cross-sections as we descend through the group in the periodic table. We have also plotted a correlation graph of the present total cross-sections with polarizability and number of target electrons. The two correlation plots confirm the credibility and consistency of the present results. Besides, this is the first theoretical attempt to report positron-impact total cross-sections of alkali atoms over such a wide energy range.

Nanostructured hybrid hydrogels prepared by a combination of atom transfer radical polymerization and free radical polymerization

PubMed Central

Bencherif, Sidi A.; Siegwart, Daniel J.; Srinivasan, Abiraman; Horkay, Ferenc; Hollinger, Jeffrey O.; Washburn, Newell R.; Matyjaszewski, Krzysztof

2012-01-01

A new method to prepare nanostructured hybrid hydrogels by incorporating well-defined poly(oligo (ethylene oxide) monomethyl ether methacrylate) (POEO300MA) nanogels of sizes 110–120 nm into a larger three-dimensional (3D) matrix was developed for drug delivery scaffolds for tissue engineering applications. Rhodamine B isothiocyanate-labeled dextran (RITC-Dx) or fluorescein isothiocyanate-labeled dextran (FITC-Dx)-loaded POEO300MA nanogels with pendant hydroxyl groups were prepared by activators generated electron transfer atom transfer radical polymerization (AGET ATRP) in cyclohexane inverse miniemulsion. Hydroxyl-containing nanogels were functionalized with methacrylated groups to generate photoreactive nanospheres. 1H NMR spectroscopy confirmed that polymerizable nanogels were successfully incorporated covalently into 3D hyaluronic acid-glycidyl methacrylate (HAGM) hydrogels after free radical photo-polymerization (FRP). The introduction of disulfide moieties into the polymerizable groups resulted in a controlled release of nanogels from cross-linked HAGM hydrogels under a reducing environment. The effect of gel hybridization on the macroscopic properties (swelling and mechanics) was studied. It is shown that swelling and nanogel content are independent of scaffold mechanics. In-vitro assays showed the nanostructured hybrid hydrogels were cytocompatible and the GRGDS (Gly–Arg–Gly–Asp–Ser) contained in the nanogel structure promoted cell–substrate interactions within 4 days of incubation. These nanostructured hydrogels have potential as an artificial extracellular matrix (ECM) impermeable to low molecular weight biomolecules and with controlled pharmaceutical release capability. Moreover, the nanogels can control drug or biomolecule delivery, while hyaluronic acid based-hydrogels can act as a macroscopic scaffold for tissue regeneration and regulator for nanogel release. PMID:19592087

Liquid crystalline ordering and charge transport in semiconducting materials.

PubMed

Pisula, Wojciech; Zorn, Matthias; Chang, Ji Young; Müllen, Klaus; Zentel, Rudolf

2009-07-16

Organic semiconducting materials offer the advantage of solution processability into flexible films. In most cases, their drawback is based on their low charge carrier mobility, which is directly related to the packing of the molecules both on local (amorphous versus crystalline) and on macroscopic (grain boundaries) length scales. Liquid crystalline ordering offers the possibility of circumventing this problem. An advanced concept comprises: i) the application of materials with different liquid crystalline phases, ii) the orientation of a low viscosity high temperature phase, and, iii) the transfer of the macroscopic orientation during cooling to a highly ordered (at best, crystalline-like) phase at room temperature. At the same time, the desired orientation for the application (OLED or field-effect transistor) can be obtained. This review presents the use of molecules with discotic, calamitic and sanidic phases and discusses the sensitivity of the phases with regard to defects depending on the dimensionality of the ordered structure (columns: 1D, smectic layers and sanidic phases: 2D). It presents ways to systematically improve charge carrier mobility by proper variation of the electronic and steric (packing) structure of the constituting molecules and to reach charge carrier mobilities that are close to and comparable to amorphous silicon, with values of 0.1 to 0.7 cm(2)  · V(-1)  · s(-1) . In this context, the significance of cross-linking to stabilize the orientation and liquid crystalline behavior of inorganic/organic hybrids is also discussed. Copyright © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Thermoablation of Malignant Kidney Tumors Using Magnetic Nanoparticles: An In Vivo Feasibility Study in a Rabbit Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bruners, Philipp, E-mail: bruners@hia.rwth-aachen.d; Braunschweig, Till; Hodenius, Michael

2010-02-15

The objective of this study was to assess the technical feasibility of CT-guided magnetic thermoablation for the treatment of malignant kidney tumors in a VX2 tumor rabbit model. VX2 tumors were implanted into the kidneys of five rabbits and allowed to grow for 2 weeks. After preinterventional CT perfusion imaging, CT-guided injection of superparamagnetic iron oxide particles (300 {mu}l) was performed, followed by exposure of the animals to an alternating electromagnetic field for 15 min ({approx}0.32 kA/m). Then animals underwent CT perfusion imaging again. Afterward, animals were sacrificed and kidneys were dissected for macroscopic and histological evaluation. Changes in perfusionmore » before and after exposure to the alternating magnetic field were analyzed. In one animal no tumor growth could be detected so the animal was used for optimization of the ablation procedure including injection technique and peri-interventional cross-sectional imaging (CT, MRI). After image-guided intratumoral injection of ferrofluids, the depiction of nanoparticle distribution by CT correlated well with macroscopic evaluation of the dissected kidneys. MRI was limited due to severe susceptibility artefacts. Postinterventional CT perfusion imaging revealed a perfusion deficiency around the ferrofluid deposits. Histological workup showed different zones of thermal damage adjacent to the ferrofluid deposits. In conclusion, CT-guided magnetic thermoablation of malignant kidney tumors is technically feasible in an animal model and results in a perfusion deficiency indicating tumor necrosis as depicted by CT perfusion imaging and shown in histological evaluation.« less

Upscaling the diffusion equations in particulate media made of highly conductive particles. II. Application to fibrous materials.

PubMed

Vassal, J-P; Orgéas, L; Favier, D; Auriault, J-L; Le Corre, S

2008-01-01

In paper I [Vassal, Phys. Rev. E77, 011302 (2008)] of this contribution, the effective diffusion properties of particulate media with highly conductive particles and particle-particle interfacial barriers have been investigated with the homogenization method with multiple scale asymptotic expansions. Three different macroscopic models have been proposed depending on the quality of contacts between particles. However, depending on the nature and the geometry of particles contained in representative elementary volumes of the considered media, localization problems to be solved to compute the effective conductivity of the two first models can rapidly become cumbersome, time and memory consuming. In this second paper, the above problem is simplified and applied to networks made of slender, wavy and entangled fibers. For these types of media, discrete formulations of localization problems for all macroscopic models can be obtained leading to very efficient numerical calculations. Semianalytical expressions of the effective conductivity tensors are also proposed under simplifying assumptions. The case of straight monodisperse and homogeneously distributed slender fibers with a circular cross section is further explored. Compact semianalytical and analytical estimations are obtained when fiber-fiber contacts are perfect or very poor. Moreover, two discrete element codes have been developed and used to solve localization problems on representative elementary volumes for the same types of contacts. Numerical results underline the significant roles of the fiber content, the orientation of fibers as well as the relative position and orientation of contacting fibers on the effective conductivity tensors. Semianalytical and analytical predictions are discussed and compared with numerical results.

Large deformation analysis of axisymmetric inhomogeneities including coupled elastic and plastic anisotropy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brannon, R.M.

1996-12-31

A mathematical framework is developed for the study of materials containing axisymmetric inclusions or flaws such as ellipsoidal voids, penny-shaped cracks, or fibers of circular cross-section. The general case of nonuniform statistical distributions of such heterogeneities is attacked by first considering a spatially uniform distribution of flaws that are all oriented in the same direction. Assuming an isotropic substrate, the macroscopic material properties of this simpler microstructure naturally should be transversely isotropic. An orthogonal basis for the linear subspace consisting of all double-symmetric transversely-isotropic fourth-order tensors associated with a given material vector is applied to deduce the explicit functional dependencemore » of the material properties of these aligned materials on the shared symmetry axis. The aligned and uniform microstructure seems geometrically simple enough that the macroscopic transversely isotropic properties could be derived in closed form. Since the resulting properties are transversely isotropic, the analyst must therefore be able to identify the appropriate coefficients of the transverse basis. Once these functions are identified, a principle of superposition of strain rates ay be applied to define an expectation integral for the composite properties of a material containing arbitrary anisotropic distributions of axisymmetric inhomogeneities. A proposal for coupling plastic anisotropy to the elastic anisotropy is presented in which the composite yield surface is interpreted as a distortion of the isotropic substrate yield surface; the distortion directions are coupled to the elastic anisotropy directions. Finally, some commonly assumed properties (such as major symmetry) of the Cauchy tangent stiffness tensor are shown to be inappropriate for large distortions of anisotropic materials.« less

Thermodynamics of urban population flows.

PubMed

Hernando, A; Plastino, A

2012-12-01

Orderliness, reflected via mathematical laws, is encountered in different frameworks involving social groups. Here we show that a thermodynamics can be constructed that macroscopically describes urban population flows. Microscopic dynamic equations and simulations with random walkers underlie the macroscopic approach. Our results might be regarded, via suitable analogies, as a step towards building an explicit social thermodynamics.

Analog modeling of Worm-Like Chain molecules using macroscopic beads-on-a-string.

PubMed

Tricard, Simon; Feinstein, Efraim; Shepherd, Robert F; Reches, Meital; Snyder, Phillip W; Bandarage, Dileni C; Prentiss, Mara; Whitesides, George M

2012-07-07

This paper describes an empirical model of polymer dynamics, based on the agitation of millimeter-sized polymeric beads. Although the interactions between the particles in the macroscopic model and those between the monomers of molecular-scale polymers are fundamentally different, both systems follow the Worm-Like Chain theory.

College Chemistry Students' Understanding of Potential Energy in the Context of Atomic-Molecular Interactions

ERIC Educational Resources Information Center

Becker, Nicole M.; Cooper, Melanie M.

2014-01-01

Understanding the energy changes that occur as atoms and molecules interact forms the foundation for understanding the macroscopic energy changes that accompany chemical processes. In order to identify ways to scaffold students' understanding of the connections between atomic-molecular and macroscopic energy perspectives, we conducted a…

X-ray Emission from the Interaction of a Macroscopic Particle with a Dense Plasma Focus.

DTIC Science & Technology

1976-10-01

Recently the interest in dense plasma focus has greatly increased because of the possibility of developing the device into an intense, pulsed...using a macroscopic particle to interact with a plasma focus . A theoretical study was carried out to predict the relative amount of X-ray increase

Efficient and accurate two-scale FE-FFT-based prediction of the effective material behavior of elasto-viscoplastic polycrystals

NASA Astrophysics Data System (ADS)

Kochmann, Julian; Wulfinghoff, Stephan; Ehle, Lisa; Mayer, Joachim; Svendsen, Bob; Reese, Stefanie

2018-06-01

Recently, two-scale FE-FFT-based methods (e.g., Spahn et al. in Comput Methods Appl Mech Eng 268:871-883, 2014; Kochmann et al. in Comput Methods Appl Mech Eng 305:89-110, 2016) have been proposed to predict the microscopic and overall mechanical behavior of heterogeneous materials. The purpose of this work is the extension to elasto-viscoplastic polycrystals, efficient and robust Fourier solvers and the prediction of micromechanical fields during macroscopic deformation processes. Assuming scale separation, the macroscopic problem is solved using the finite element method. The solution of the microscopic problem, which is embedded as a periodic unit cell (UC) in each macroscopic integration point, is found by employing fast Fourier transforms, fixed-point and Newton-Krylov methods. The overall material behavior is defined by the mean UC response. In order to ensure spatially converged micromechanical fields as well as feasible overall CPU times, an efficient but simple solution strategy for two-scale simulations is proposed. As an example, the constitutive behavior of 42CrMo4 steel is predicted during macroscopic three-point bending tests.

Macroscopic Models of Local Field Potentials and the Apparent 1/f Noise in Brain Activity

PubMed Central

Bédard, Claude; Destexhe, Alain

2009-01-01

The power spectrum of local field potentials (LFPs) has been reported to scale as the inverse of the frequency, but the origin of this 1/f noise is at present unclear. Macroscopic measurements in cortical tissue demonstrated that electric conductivity (as well as permittivity) is frequency-dependent, while other measurements failed to evidence any dependence on frequency. In this article, we propose a model of the genesis of LFPs that accounts for the above data and contradictions. Starting from first principles (Maxwell equations), we introduce a macroscopic formalism in which macroscopic measurements are naturally incorporated, and also examine different physical causes for the frequency dependence. We suggest that ionic diffusion primes over electric field effects, and is responsible for the frequency dependence. This explains the contradictory observations, and also reproduces the 1/f power spectral structure of LFPs, as well as more complex frequency scaling. Finally, we suggest a measurement method to reveal the frequency dependence of current propagation in biological tissue, and which could be used to directly test the predictions of this formalism. PMID:19348744

Modelling of electronic excitation and radiation in the Direct Simulation Monte Carlo Macroscopic Chemistry Method

NASA Astrophysics Data System (ADS)

Goldsworthy, M. J.

2012-10-01

One of the most useful tools for modelling rarefied hypersonic flows is the Direct Simulation Monte Carlo (DSMC) method. Simulator particle movement and collision calculations are combined with statistical procedures to model thermal non-equilibrium flow-fields described by the Boltzmann equation. The Macroscopic Chemistry Method for DSMC simulations was developed to simplify the inclusion of complex thermal non-equilibrium chemistry. The macroscopic approach uses statistical information which is calculated during the DSMC solution process in the modelling procedures. Here it is shown how inclusion of macroscopic information in models of chemical kinetics, electronic excitation, ionization, and radiation can enhance the capabilities of DSMC to model flow-fields where a range of physical processes occur. The approach is applied to the modelling of a 6.4 km/s nitrogen shock wave and results are compared with those from existing shock-tube experiments and continuum calculations. Reasonable agreement between the methods is obtained. The quality of the comparison is highly dependent on the set of vibrational relaxation and chemical kinetic parameters employed.

Efficient and accurate two-scale FE-FFT-based prediction of the effective material behavior of elasto-viscoplastic polycrystals

NASA Astrophysics Data System (ADS)

Kochmann, Julian; Wulfinghoff, Stephan; Ehle, Lisa; Mayer, Joachim; Svendsen, Bob; Reese, Stefanie

2017-09-01

Recently, two-scale FE-FFT-based methods (e.g., Spahn et al. in Comput Methods Appl Mech Eng 268:871-883, 2014; Kochmann et al. in Comput Methods Appl Mech Eng 305:89-110, 2016) have been proposed to predict the microscopic and overall mechanical behavior of heterogeneous materials. The purpose of this work is the extension to elasto-viscoplastic polycrystals, efficient and robust Fourier solvers and the prediction of micromechanical fields during macroscopic deformation processes. Assuming scale separation, the macroscopic problem is solved using the finite element method. The solution of the microscopic problem, which is embedded as a periodic unit cell (UC) in each macroscopic integration point, is found by employing fast Fourier transforms, fixed-point and Newton-Krylov methods. The overall material behavior is defined by the mean UC response. In order to ensure spatially converged micromechanical fields as well as feasible overall CPU times, an efficient but simple solution strategy for two-scale simulations is proposed. As an example, the constitutive behavior of 42CrMo4 steel is predicted during macroscopic three-point bending tests.

Biomineral nanoparticles are space-filling

NASA Astrophysics Data System (ADS)

Yang, Li; Killian, Christopher E.; Kunz, Martin; Tamura, Nobumichi; Gilbert, P. U. P. A.

2011-02-01

Sea urchin biominerals have been shown to form from aggregating nanoparticles of amorphous calcium carbonate (ACC), which then crystallize into macroscopic single crystals of calcite. Here we measure the surface areas of these biominerals and find them to be comparable to those of space-filling macroscopic geologic calcite crystals. These biominerals differ from synthetic mesocrystals, which are invariably porous. We propose that space-filling ACC is the structural precursor for echinoderm biominerals.Sea urchin biominerals have been shown to form from aggregating nanoparticles of amorphous calcium carbonate (ACC), which then crystallize into macroscopic single crystals of calcite. Here we measure the surface areas of these biominerals and find them to be comparable to those of space-filling macroscopic geologic calcite crystals. These biominerals differ from synthetic mesocrystals, which are invariably porous. We propose that space-filling ACC is the structural precursor for echinoderm biominerals. This article was submitted as part of a Themed Issue on Crystallization and Formation Mechanisms of Nanostructures. Other papers on this topic can be found in issue 11 of vol. 2 (2010). This issue can be found from the Nanoscale homepage [http://www.rsc.org/nanoscale

A technique to functionalize and self-assemble macroscopic nanoparticle-ligand monolayer films onto template-free substrates.

PubMed

Fontana, Jake; Spillmann, Christopher; Naciri, Jawad; Ratna, Banahalli R

2014-05-09

This protocol describes a self-assembly technique to create macroscopic monolayer films composed of ligand-coated nanoparticles. The simple, robust and scalable technique efficiently functionalizes metallic nanoparticles with thiol-ligands in a miscible water/organic solvent mixture allowing for rapid grafting of thiol groups onto the gold nanoparticle surface. The hydrophobic ligands on the nanoparticles then quickly phase separate the nanoparticles from the aqueous based suspension and confine them to the air-fluid interface. This drives the ligand-capped nanoparticles to form monolayer domains at the air-fluid interface. The use of water-miscible organic solvents is important as it enables the transport of the nanoparticles from the interface onto template-free substrates. The flow is mediated by a surface tension gradient and creates macroscopic, high-density, monolayer nanoparticle-ligand films. This self-assembly technique may be generalized to include the use of particles of different compositions, size, and shape and may lead to an efficient assembly method to produce low-cost, macroscopic, high-density, monolayer nanoparticle films for wide-spread applications.

On the effect of irradiation-induced resolution in modelling fission gas release in UO2 LWR fuel

NASA Astrophysics Data System (ADS)

Lösönen, Pekka

2017-12-01

Irradiation resolution of gas atoms and vacancies from intra- and intergranular bubbles in sintered UO2 fuel was studied by comparing macroscopic models with a more mechanistic approach. The applied macroscopic models imply the resolution rate of gas atoms to be proportional to gas concentration in intragranular bubbles and at grain boundary (including intergranular bubbles). A relation was established between the macroscopic models and a single encounter of an energetic fission fragment with a bubble. The effect of bubble size on resolution was quantified. The number of resoluted gas atoms per encounter of a fission fragment per bubble was of the same order of magnitude for intra- and intergranular bubbles. However, the resulting macroscopic resolution rate of gas atoms was about two orders of magnitude larger from intragranular bubbles. The number of vacancies resoluted from a grain face bubble by a passing fission fragment was calculated. The obtained correlations for resolution of gas atoms from intragranular bubbles and grain boundaries and for resolution of vacancies from grain face bubbles were used to demonstrate the effect of irradiation resolution on fission gas release.

Total Cross Sections as a Surrogate for Neutron Capture: An Opportunity to Accurately Constrain (n,γ) Cross Sections for Nuclides Beyond the Reach of Direct Measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koehler, Paul E.

2014-03-05

There are many (n,γ) cross sections of great interest to radiochemical diagnostics and to nuclear astrophysics which are beyond the reach of current measurement techniques, and likely to remain so for the foreseeable future. In contrast, total neutron cross sections currently are feasible for many of these nuclides and provide almost all the information needed to accurately calculate the (n,γ) cross sections via the nuclear statistical model (NSM). I demonstrate this for the case of 151Sm; NSM calculations constrained using average resonance parameters obtained from total cross section measurements made in 1975, are in excellent agreement with recent 151Sm (n,γ)more » measurements across a wide range of energy. Furthermore, I demonstrate through simulations that total cross section measurements can be made at the Manuel Lujan Jr. Neutron Scattering Center at the Los Alamos Neutron Science Center for samples as small as 10μg. Samples of this size should be attainable for many nuclides of interest. Finally, I estimate that over half of the radionuclides identified ~20 years ago as having (n,γ) cross sections of importance to s-process nucleosynthesis studies (24/43) and radiochemical diagnostics (11/19), almost none of which have been measured, can be constrained using this technique.« less

Scaling from single molecule to macroscopic adhesion at polymer/metal interfaces.

PubMed

Utzig, Thomas; Raman, Sangeetha; Valtiner, Markus

2015-03-10

Understanding the evolution of macroscopic adhesion based on fundamental molecular interactions is crucial to designing strong and smart polymer/metal interfaces that play an important role in many industrial and biomedical applications. Here we show how macroscopic adhesion can be predicted on the basis of single molecular interactions. In particular, we carry out dynamic single molecule-force spectroscopy (SM-AFM) in the framework of Bell-Evans' theory to gain information about the energy barrier between the bound and unbound states of an amine/gold junction. Furthermore, we use Jarzynski's equality to obtain the equilibrium ground-state energy difference of the amine/gold bond from these nonequilibrium force measurements. In addition, we perform surface forces apparatus (SFA) experiments to measure macroscopic adhesion forces at contacts where approximately 10(7) amine/gold bonds are formed simultaneously. The SFA approach provides an amine/gold interaction energy (normalized by the number of interacting molecules) of (36 ± 1)k(B)T, which is in excellent agreement with the interaction free energy of (35 ± 3)k(B)T calculated using Jarzynski's equality and single-molecule AFM experiments. Our results validate Jarzynski's equality for the field of polymer/metal interactions by measuring both sides of the equation. Furthermore, the comparison of SFA and AFM shows how macroscopic interaction energies can be predicted on the basis of single molecular interactions, providing a new strategy to potentially predict adhesive properties of novel glues or coatings as well as bio- and wet adhesion.

Limit analysis and homogenization of porous materials with Mohr-Coulomb matrix. Part I: Theoretical formulation

NASA Astrophysics Data System (ADS)

Anoukou, K.; Pastor, F.; Dufrenoy, P.; Kondo, D.

2016-06-01

The present two-part study aims at investigating the specific effects of Mohr-Coulomb matrix on the strength of ductile porous materials by using a kinematic limit analysis approach. While in the Part II, static and kinematic bounds are numerically derived and used for validation purpose, the present Part I focuses on the theoretical formulation of a macroscopic strength criterion for porous Mohr-Coulomb materials. To this end, we consider a hollow sphere model with a rigid perfectly plastic Mohr-Coulomb matrix, subjected to axisymmetric uniform strain rate boundary conditions. Taking advantage of an appropriate family of three-parameter trial velocity fields accounting for the specific plastic deformation mechanisms of the Mohr-Coulomb matrix, we then provide a solution of the constrained minimization problem required for the determination of the macroscopic dissipation function. The macroscopic strength criterion is then obtained by means of the Lagrangian method combined with Karush-Kuhn-Tucker conditions. After a careful analysis and discussion of the plastic admissibility condition associated to the Mohr-Coulomb criterion, the above procedure leads to a parametric closed-form expression of the macroscopic strength criterion. The latter explicitly shows a dependence on the three stress invariants. In the special case of a friction angle equal to zero, the established criterion reduced to recently available results for porous Tresca materials. Finally, both effects of matrix friction angle and porosity are briefly illustrated and, for completeness, the macroscopic plastic flow rule and the voids evolution law are fully furnished.

Management of macroscopic haematuria in the emergency department

PubMed Central

Hicks, Derek; Li, Chi‐Ying

2007-01-01

Macroscopic haematuria is a commonly seen condition in the emergency department (ED), which has a variety of causes. However, most importantly, macroscopic haematuria has a high diagnostic yield for urological malignancy. 30% of patients presenting with painless haematuria are found to have a malignancy. The majority of these patients can be managed in the outpatient setting. This review of current literature suggests a management pathway that can be used in the ED. A literature search was done using Medline, PubMed and Google. In men aged >60 years, the positive predictive value of macroscopic haematuria for urological malignancy is 22.1%, and in women of the same age it is 8.3%. In terms of the need for follow‐up investigation, a single episode of haematuria is equally important as recurrent episodes. Baseline investigation in the ED includes full blood count, urea and electrolyte levels, midstream urine dipstick, β human chorionic gonadotrophin, and formal microscopy, culture and sensitivities. Treatment of macroscopic haematuria aims at RESP—Resuscitation, Ensuring, Safe and Prompt. Indications for admission include clot retention, cardiovascular instability, uncontrolled pain, sepsis, acute renal failure, coagulopathy, severe comorbidity, heavy haematuria or social restrictions. Discharged patients should drink plenty of clear fluids and return for further medical attention if the following occur: clot retention, worsening haematuria despite adequate fluid intake, uncontrolled pain or fever, or inability to cope at home. Follow‐up by a urological team should be promptly arranged, ideally within the 2‐week cancer referral target. PMID:17513531

Patients with gastrointestinal complains due to enteric parasites, with reference to Entamoeba histolytica/dispar as dected by ELISA E. histolytica adhesion in stool.

PubMed

El-Kadi, Mohammad A; Dorrah, Ahmad O; Shoukry, Nahla M

2006-04-01

A total of 210 patients with gastrointestinal troubles, of both sex and a mean age of 32 +/- 6.1 years, selected from the outpatient's clinics of Al-Azhar University Hospitals. 115 (54.76%) had dysentery, 95 (45.23%) did not have dysentery, 15 (14%) suffered flatulence, 20 (9.52%) had epi-gastric pain, 19 (9.05%) had vague abdominal pain, 5 vomiting (5.2%) and 10 (4.9%) had fever. Two symptoms were in 29 (13.81%) patients and three symptoms in 12 (5.71%). Of the 210 patients, 20 (9.9%) had helminthes infection, 121 (57.6%) had intestinal protozoa and 69 (32.9%) had no parasitic infection. Of these parasite-free patients, 16 had Shigella sp. and nine had Campylobacter sp. Of the patients with intestinal protozoa, 34 (16.2%) had E. histolytica/dispar by stool examination of stained smears. By using ELISA for detection of E. histolytica adhesion in stool samples of 115 with diarrhea only 18 had true E. histolytica infection and of 3 without diarrhea only one had E. histolytica infection. Mean-while, ELISA did not cross-reacted E. coli, Giardia lamblia, Cryptosporidium parvum, Endolimax nana or Blastocystis hominis. So, ELISA for detection of E. histolytica adhesion in stool samples was more specific than microscopy and safe direction to the E. histolytica treatment. Apart from intestinal protozoan and bacteria, helminthes were seen in stool analysis. These were Schistosoma mansoni (0.95%), Capillaria sp. (0.95%), Enterobius vermicularis (1.90%) macroscopically, Hymenolepis nana (4.3%) and Ascaris lumbricoides (1.43%).

Consistent second-order boundary implementations for convection-diffusion lattice Boltzmann method

NASA Astrophysics Data System (ADS)

Zhang, Liangqi; Yang, Shiliang; Zeng, Zhong; Chew, Jia Wei

2018-02-01

In this study, an alternative second-order boundary scheme is proposed under the framework of the convection-diffusion lattice Boltzmann (LB) method for both straight and curved geometries. With the proposed scheme, boundary implementations are developed for the Dirichlet, Neumann and linear Robin conditions in a consistent way. The Chapman-Enskog analysis and the Hermite polynomial expansion technique are first applied to derive the explicit expression for the general distribution function with second-order accuracy. Then, the macroscopic variables involved in the expression for the distribution function is determined by the prescribed macroscopic constraints and the known distribution functions after streaming [see the paragraph after Eq. (29) for the discussions of the "streaming step" in LB method]. After that, the unknown distribution functions are obtained from the derived macroscopic information at the boundary nodes. For straight boundaries, boundary nodes are directly placed at the physical boundary surface, and the present scheme is applied directly. When extending the present scheme to curved geometries, a local curvilinear coordinate system and first-order Taylor expansion are introduced to relate the macroscopic variables at the boundary nodes to the physical constraints at the curved boundary surface. In essence, the unknown distribution functions at the boundary node are derived from the known distribution functions at the same node in accordance with the macroscopic boundary conditions at the surface. Therefore, the advantages of the present boundary implementations are (i) the locality, i.e., no information from neighboring fluid nodes is required; (ii) the consistency, i.e., the physical boundary constraints are directly applied when determining the macroscopic variables at the boundary nodes, thus the three kinds of conditions are realized in a consistent way. It should be noted that the present focus is on two-dimensional cases, and theoretical derivations as well as the numerical validations are performed in the framework of the two-dimensional five-velocity lattice model.

AFM Study of Surface Nanobubbles on Binary Self-Assembled Monolayers on Ultraflat Gold with Identical Macroscopic Static Water Contact Angles and Different Terminal Functional Groups.

PubMed

Song, Bo; Chen, Kun; Schmittel, Michael; Schönherr, Holger

2016-11-01

All experimental findings related to surface nanobubbles, such as their pronounced stability and the striking differences of macroscopic and apparent nanoscopic contact angles, need to be addressed in any theory or model of surface nanobubbles. In this work we critically test a recent explanation of surface nanobubble stability and their consequences and contrast this with previously proposed models. In particular, we elucidated the effect of surface chemical composition of well-controlled solid-aqueous interfaces of identical roughness and defect density on the apparent nanoscopic contact angles. Expanding on a previous atomic force microscopy (AFM) study on the systematic variation of the macroscopic wettability using binary self-assembled monolayers (SAMs) on ultraflat template stripped gold (TSG), we assessed here the effect of different surface chemical composition for macroscopically identical static water contact angles. SAMs on TSG with a constant macroscopic water contact angle of 81 ± 2° were obtained by coadsorption of a methyl-terminated thiol and a second thiol with different terminal functional groups, including hydroxy, amino, and carboxylic acid groups. In addition, surface nanobubbles formed by entrainment of air on SAMs of a bromoisobutyrate-terminated thiol were analyzed by AFM. Despite the widely differing surface potentials and different functionality, such as hydrogen bond acceptor or donor, and different dipole moments and polarizability, the nanoscopic contact angles (measured through the condensed phase and corrected for AFM tip broadening effects) were found to be 145 ± 10° for all surfaces. Hence, different chemical functionalities at identical macroscopic static water contact angle do not noticeably influence the apparent nanoscopic contact angle of surface nanobubbles. This universal contact angle is in agreement with recent models that rely on contact line pinning and the equilibrium of gas outflux due to the Laplace pressure and gas influx due to gas oversaturation in the aqueous medium.

Use of a 3-Telsa magnet to perform delayed gadolinium-enhanced magnetic resonance imaging of the distal interphalangeal joint of horses with and without naturally occurring osteoarthritis.

PubMed

Bischofberger, Andrea S; Fürst, Anton E; Torgerson, Paul R; Carstens, Ann; Hilbe, Monika; Kircher, Patrick

2018-03-01

OBJECTIVE To characterize delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) features of healthy hyaline cartilage of the distal interphalangeal joint (DIPJ) of horses, to determine whether dGEMRIC can be used to differentiate various stages of naturally occurring osteoarthritis of the DIPJ, and to correlate relaxation times determined by dGEMRIC with the glycosaminoglycan concentration, water content, and macroscopic and histologic findings of hyaline cartilage of DIPJs with and without osteoarthritis. SAMPLE 1 cadaveric forelimb DIPJ from each of 12 adult warmblood horses. PROCEDURES T1-weighted cartilage relaxation times were obtained for predetermined sites of the DIPJ before (T1 preGd ) and after (T1 postGd ) intra-articular gadolinium administration. Corresponding cartilage sites underwent macroscopic, histologic, and immunohistochemical evaluation, and cartilage glycosaminoglycan concentration and water content were determined. Median T1 preGd and T1 postGd were correlated with macroscopic, histologic, and biochemical data. Mixed generalized linear models were created to evaluate the effects of cartilage site, articular surface, and macroscopic and histologic scores on relaxation times. RESULTS 122 cartilage specimens were analyzed. Median T1 postGd was lower than the median T1 preGd for normal and diseased cartilage. Both T1 preGd and T1 postGd were correlated with macroscopic and histologic scores, whereby T1 preGd increased and T1 postGd decreased as osteoarthritis progressed. There was topographic variation of T1 preGd and T1 postGd within the DIPJ. Cartilage glycosaminoglycan concentration and water content were significantly correlated with T1 preGd and macroscopic and histologic scores but were not correlated with T1 postGd . CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that dGEMRIC relaxation times varied for DIPJs with various degrees of osteoarthritis. These findings may help facilitate early detection of osteoarthritis.

Electron collisions with phenol: Total, integral, differential, and momentum transfer cross sections and the role of multichannel coupling effects on the elastic channel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Costa, Romarly F. da; Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, 09210-580 Santo André, São Paulo; Oliveira, Eliane M. de

2015-03-14

We report theoretical and experimental total cross sections for electron scattering by phenol (C{sub 6}H{sub 5}OH). The experimental data were obtained with an apparatus based in Madrid and the calculated cross sections with two different methodologies, the independent atom method with screening corrected additivity rule (IAM-SCAR), and the Schwinger multichannel method with pseudopotentials (SMCPP). The SMCPP method in the N{sub open}-channel coupling scheme, at the static-exchange-plus-polarization approximation, is employed to calculate the scattering amplitudes at impact energies ranging from 5.0 eV to 50 eV. We discuss the multichannel coupling effects in the calculated cross sections, in particular how the numbermore » of excited states included in the open-channel space impacts upon the convergence of the elastic cross sections at higher collision energies. The IAM-SCAR approach was also used to obtain the elastic differential cross sections (DCSs) and for correcting the experimental total cross sections for the so-called forward angle scattering effect. We found a very good agreement between our SMCPP theoretical differential, integral, and momentum transfer cross sections and experimental data for benzene (a molecule differing from phenol by replacing a hydrogen atom in benzene with a hydroxyl group). Although some discrepancies were found for lower energies, the agreement between the SMCPP data and the DCSs obtained with the IAM-SCAR method improves, as expected, as the impact energy increases. We also have a good agreement among the present SMCPP calculated total cross section (which includes elastic, 32 inelastic electronic excitation processes and ionization contributions, the latter estimated with the binary-encounter-Bethe model), the IAM-SCAR total cross section, and the experimental data when the latter is corrected for the forward angle scattering effect [Fuss et al., Phys. Rev. A 88, 042702 (2013)].« less

Measurement of the total hadronic cross section in e+e- annihilation below 10.56GeV

NASA Astrophysics Data System (ADS)

Besson, D.; Pedlar, T. K.; Cronin-Hennessy, D.; Gao, K. Y.; Hietala, J.; Klein, T.; Kubota, Y.; Lang, B. W.; Poling, R.; Scott, A. W.; Smith, A.; Zweber, P.; Dobbs, S.; Metreveli, Z.; Seth, K. K.; Tomaradze, A.; Ernst, J.; Ecklund, K. M.; Severini, H.; Dytman, S. A.; Love, W.; Savinov, V.; Aquines, O.; Lopez, A.; Mehrabyan, S.; Mendez, H.; Ramirez, J.; Huang, G. S.; Miller, D. H.; Pavlunin, V.; Sanghi, B.; Shipsey, I. P. J.; Xin, B.; Adams, G. S.; Anderson, M.; Cummings, J. P.; Danko, I.; Hu, D.; Moziak, B.; Napolitano, J.; He, Q.; Insler, J.; Muramatsu, H.; Park, C. S.; Thorndike, E. H.; Yang, F.; Artuso, M.; Blusk, S.; Butt, J.; Li, J.; Menaa, N.; Mountain, R.; Nisar, S.; Randrianarivony, K.; Sia, R.; Skwarnicki, T.; Stone, S.; Wang, J. C.; Zhang, K.; Bonvicini, G.; Cinabro, D.; Dubrovin, M.; Lincoln, A.; Asner, D. M.; Edwards, K. W.; Naik, P.; Briere, R. A.; Ferguson, T.; Tatishvili, G.; Vogel, H.; Watkins, M. E.; Rosner, J. L.; Adam, N. E.; Alexander, J. P.; Berkelman, K.; Cassel, D. G.; Duboscq, J. E.; Ehrlich, R.; Fields, L.; Galik, R. S.; Gibbons, L.; Gray, R.; Gray, S. W.; Hartill, D. L.; Heltsley, B. K.; Hertz, D.; Jones, C. D.; Kandaswamy, J.; Kreinick, D. L.; Kuznetsov, V. E.; Mahlke-Krüger, H.; Mohapatra, D.; Onyisi, P. U. E.; Patterson, J. R.; Peterson, D.; Pivarski, J.; Riley, D.; Ryd, A.; Sadoff, A. J.; Schwarthoff, H.; Shi, X.; Stroiney, S.; Sun, W. M.; Wilksen, T.; Athar, S. B.; Patel, R.; Potlia, V.; Yelton, J.; Rubin, P.; Cawlfield, C.; Eisenstein, B. I.; Karliner, I.; Kim, D.; Lowrey, N.; Selen, M.; White, E. J.; Wiss, J.; Mitchell, R. E.; Shepherd, M. R.

2007-10-01

Using the CLEO III detector, we measure absolute cross sections for e+e-→hadrons at seven center-of-mass energies between 6.964 and 10.538 GeV. The values of R, the ratio of hadronic and muon pair production cross sections, are determined within 2% total root-mean-square uncertainty.

Total photoionization cross sections of atomic oxygen from threshold to 44.3 A

NASA Technical Reports Server (NTRS)

Angel, G. C.; Samson, James A. R.

1988-01-01

Synchrotron radiation was used to obtain the relative photoionization cross section of atomic oxygen for the production of singly charged ions over the 44.3-910.5-A wavelength range. Measurement of the contribution of multiple ionization to the cross sections has made possible the determination of total photoionization cross sections below 250 A. The series of autoionizing resonances leading to the 4P state of the oxygen ion has been observed using an ionization-type experimental procedure for the first time.

Hydrology and water quality of Little Cross Creek, Cumberland County, North Carolina, 1996-98

USGS Publications Warehouse

Giorgino, Mary J.; Middleton, Terry L.

2000-01-01

Little Cross Creek is a small stream located in Cumberland County, North Carolina, in the Sand Hills area of the Coastal Plain Province. From August 1996 through August 1998, the U.S. Geological Survey collected streamflow, water-quality, and time-of-travel data at 10 sites in Little Cross Creek Basin to assess ambient conditions and compute loads of suspended sediment, total nitrogen, total phosphorus, and total organic carbon. Streamflows in the Little Cross Creek Basin responded to climatic factors and to human activities such as water withdrawals and controlled releases from impoundments. Peak streamflows were observed during the passages of Hurricane Fran in September 1996 and Hurricane Josephine in October 1996. Streamflows generally were lowest during the summer and early fall of 1997, reflecting drought conditions associated with a prevailing El Nino. At most sites, average streamflow per unit drainage area, or yield, was higher than yields reported previously for the Sand Hills. High yields may have resulted from unidentified inputs of water to the study basins or from underestimation of the contributing drainage area. Bonnie Doone Lake, Kornbow Lake, Mintz Pond, and Glenville Lake, four impoundments of Little Cross Creek, notably influence hydrology and water quality in the basin. Streamflow records indicate that these impoundments dampen peak stormflows and delay the downstream release of stormwater. Time of travel also is affected by seasonal stratification in the reservoirs. In general, sites downstream from reservoirs have lower concentrations of suspended sediment, turbidity, and total phosphorus than sites upstream from reservoirs or sites that receive stormwater runoff. Few water-quality problems were observed in the Little Cross Creek Basin for the constituents that were sampled. However, fecal coliform bacteria commonly exceeded 200 colonies per 100 milliliters at two of the seven monitored sites during the study. Relatively high concentrations of specific conductance, total phosphorus, and total ammonia plus organic nitrogen were observed in Clark Pond Creek, a tributary to Little Cross Creek. Loads and yields of suspended sediment, total nitrogen, total phosphorus, and total organic carbon were computed for the period from October 1996 through September 1997. The highest suspended-sediment yield (230 tons per square mile per year) occurred upstream from Bonnie Doone Lake, probably because there were no impoundments upstream from this site to intercept sediment. Sediment yields at the remaining Little Cross Creek sites were low relative to yields reported from other urban basins in North Carolina. Downstream from Kornbow Lake, yields of suspended sediment (9.50 tons per square mile per year) and total phosphorus (0.011 ton per square mile per year) were very low. Clark Pond Creek had the highest yields ot total phosphorus (0.081 ton per square mile per year) and total organic carbon (11.5 tons per square mile per year). However, total phosphorus yields at all of the Little Cross Creek sites generally were lower than yields measured in other urban basins in the State. Comparison of inflow and outflow loads for the four Little Cross Creek reservoirs from October 1996 through September 1997 indicated that Bonnie Doone Lake trapped 92 percent of incoming sediment and 37 percent of incoming total phosphorus. Kornbow Lake trapped 57 percent of incoming sediment and 77 percent of total phosphorus inputs. Nitrogen was not effectively trapped by any of the reservoirs. An influx of sediment, total phosphorus, and total organic carbon was noted at a site downstream from Mintz Pond, and may have resulted from stormwater discharge from the U.S. Highway 401 bypass or from additional, unidentified sources in the watershed downstream from Kornbow Lake.

Electron-Impact Total Ionization Cross Sections of CH and C2H2

PubMed Central

Kim, Yong-Ki; Ali, M. Asgar; Rudd, M. Eugene

1997-01-01

Electron-impact total ionization cross sections for the CH radical and C2H2 (acetylene) have been calculated using the Binary-Encounter-Bethe (BEB) model. The BEB model combines the Mott cross section and the asymptotic form of the Bethe theory, and has been shown to generate reliable ionization cross sections for a large variety of molecules. The BEB cross sections for CH and C2H2 are in good agreement with the available experimental data from ionization thresholds to hundreds of eV in incident energies. PMID:27805116

Simple method for determining fullerene negative ion formation★

NASA Astrophysics Data System (ADS)

Felfli, Zineb; Msezane, Alfred Z.

2018-04-01

A robust potential wherein is embedded the crucial core-polarization interaction is used in the Regge-pole methodology to calculate low-energy electron elastic scattering total cross section for the C60 fullerene in the electron impact energy range 0.02 ≤ E ≤ 10.0 eV. The energy position of the characteristic dramatically sharp resonance appearing at the second Ramsauer-Townsend minimum of the total cross section representing stable C60 - fullerene negative ion formation agrees excellently with the measured electron affinity of C60 [Huang et al., J. Chem. Phys. 140, 224315 (2014)]. The benchmarked potential and the Regge-pole methodology are then used to calculate electron elastic scattering total cross sections for selected fullerenes, from C54 through C240. The total cross sections are found to be characterized generally by Ramsauer-Townsend minima, shape resonances and dramatically sharp resonances representing long-lived states of fullerene negative ion formation. For the total cross sections of C70, C76, C78, and C84 the agreement between the energy positions of the very sharp resonances and the measured electron affinities is outstanding. Additionally, we compare our extracted energy positions of the resultant fullerene anions from our calculated total cross sections of the C86, C90 and C92 fullerenes with the estimated electron affinities ≥3.0 eV by the experiment [Boltalina et al., Rapid Commun. Mass Spectrom. 7, 1009 (1993)]. Resonance energy positions of other fullerenes, including C180 and C240 are also obtained. Most of the total cross sections presented in this paper are the first and only; our novel approach is general and should be applicable to other fullerenes as well and complex heavy atoms, such as the lanthanide atoms. We conclude with a remark on the catalytic properties of the fullerenes through their negative ions.

Students' Mind Wandering in Macroscopic and Submicroscopic Textual Narrations and Its Relationship with Their Reading Comprehension

ERIC Educational Resources Information Center

Al-Balushi, Sulaiman M.; Al-Harthy, Ibrahim S.

2015-01-01

The aim of the current study was to investigate students' mind wandering while reading different types of textual narrations (macroscopic and submicroscopic) in chemistry. Another goal was to determine the relationship between mind wandering and students' reading comprehension. The participants were 65 female ninth grade students in Oman. Using a…

The Molecular Boat: A Hands-On Experiment to Demonstrate the Forces Applied to Self-Assembled Monolayers at Interfaces

ERIC Educational Resources Information Center

Chan, Charlene J.; Salaita, Khalid

2012-01-01

Demonstrating how surface chemistry and self-assembled monolayers (SAMs) control the macroscopic properties of materials is challenging as it often necessitates the use of specialized instrumentation. In this hands-on experiment, students directly measure a macroscopic property, the floatation of glass coverslips on water as a function of…

Vascular flora and macroscopic fauna on the Fernow Experimental Forest

Treesearch

Darlene M. Madarish; Jane L. Rodrigue; Mary Beth Adams

2002-01-01

This report is the first comprehensive inventory of the vascular flora and macroscopic fauna known to occur within the Fernow Experimental Forest in north-central West Virignia. The compendium is based on information obtained from previous surveys, current research, and the personal observations of USDA Forest Service personnel and independent scientists. More than 750...

Production of squeezed states for macroscopic mechanical oscillator

NASA Technical Reports Server (NTRS)

Kulagin, V. V.

1994-01-01

The possibility of squeezed states generation for macroscopic mechanical oscillator is discussed. It is shown that one can obtain mechanical oscillator in squeezed state via coupling it to electromagnetic oscillator (Fabry-Perot resonator) and pumping this Fabry-Perot resonator with a field in squeezed state. The degradation of squeezing due to mechanical and optical losses is also analyzed.

SORPTION OF ARSENATE AND ARSENITE ON RUO2.XH2O: A SPECTROSCOPIC AND MACROSCOPIC STUDY

EPA Science Inventory

The sorption of arsenate (As(V)) and arsenite (As(III)) on RuO2 xH2O was examined using macroscopic and microscopic techniques. Constant solid:solution ratio isotherms were constructed from batch sorption experiments to study the sorption of the inorganic arsenic species on RuO2...

Understanding of Macroscopic, Microscopic and Symbolic Representations among Form Four Students in Solving Stoichiometric Problems

ERIC Educational Resources Information Center

Sujak, Kamariah Binti; Daniel, Esther Gnanamalar Sarojini

2017-01-01

The purpose of this article is to determine the levels of understanding for solving Stoichiometry problems from the aspect of macroscopic, microscopic and symbolic representations of high, average and low achieving students after infusion of metacognitive skills. Nine form four students aged sixteen years old from a secondary school in Kuala…

An Analysis of Indonesian and Japanese Students' Understandings of Macroscopic and Submicroscopic Levels of Representing Matter and Its Changes

ERIC Educational Resources Information Center

Rahayu, Sri; Kita, Masakazu

2010-01-01

This study investigated Indonesian and Japanese students' understandings of macroscopic and submicroscopic levels of representing matter and its changes and the difficulties they have with these concepts. A multiple-choice questionnaire was constructed and delivered to 447 Indonesian and 446 Japanese public senior high school students. The data…

Scaling of chaos in strongly nonlinear lattices.

PubMed

Mulansky, Mario

2014-06-01

Although it is now understood that chaos in complex classical systems is the foundation of thermodynamic behavior, the detailed relations between the microscopic properties of the chaotic dynamics and the macroscopic thermodynamic observations still remain mostly in the dark. In this work, we numerically analyze the probability of chaos in strongly nonlinear Hamiltonian systems and find different scaling properties depending on the nonlinear structure of the model. We argue that these different scaling laws of chaos have definite consequences for the macroscopic diffusive behavior, as chaos is the microscopic mechanism of diffusion. This is compared with previous results on chaotic diffusion [M. Mulansky and A. Pikovsky, New J. Phys. 15, 053015 (2013)], and a relation between microscopic chaos and macroscopic diffusion is established.

Vesicle solubilization by bile salts: comparison of macroscopic theory and simulation.

PubMed

Haustein, M; Wahab, M; Mögel, H-J; Schiller, P

2015-04-14

Lipid metabolism is accompanied by the solubilization of lipid bilayer membranes by bile salts. We use Brownian dynamics simulations to study the solubilization of model membranes and vesicles by sodium cholate. The solubilization pathways of small and large vesicles are found to be different. Both results for small and large vesicles can be compared with predictions of a macroscopic theoretical description. The line tension of bilayer edges is an important parameter in the solubilization process. We propose a simple method to determine the line tension by analyzing the shape fluctuations of planar membrane patches. Macroscopic mechanical models provide a reasonable explanation for processes observed when a spherical vesicle consisting of lipids and adsorbed bile salt molecules is transformed into mixed lipid-bile salt micelles.

Hydrodynamic dispersion in porous media with macroscopic disorder of parameters

NASA Astrophysics Data System (ADS)

Goldobin, D. S.; Maryshev, B. S.

2017-10-01

We present an analytical derivation of the macroscopic hydrodynamic dispersion for flows in porous media with frozen disorder of macroscopic parameters: porosity and permeability. The parameter inhomogeneities generate inhomogeneities of filtration flow which perform fluid mixing and, on the large spacial scale, act as an additional effective diffusion (eddy diffusivity or hydrodynamic dispersion). The derivation is performed for the general case, where the only restrictions are (i) the spatial autocorrelation functions of parameter inhomogeneities decay with the distance r not slower than 1/rn with n > 1, and (ii) the amplitudes of inhomogeneities are small compared to the mean value of parameters. Our analytical findings are confirmed with the results of direct numerical simulation for the transport of a passive scalar in inhomogeneous filtration flow.

Single crystal to polycrystal neutron transmission simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dessieux, Luc Lucius; Stoica, Alexandru Dan; Bingham, Philip R.

A collection of routines for calculation of the total cross section that determines the attenuation of neutrons by crystalline solids is presented. The total cross section is calculated semi-empirically as a function of crystal structure, neutron energy, temperature, and crystal orientation. The semi-empirical formula includes the contribution of parasitic Bragg scattering to the total cross section using both the crystal’s mosaic spread value and its orientation with respect to the neutron beam direction as parameters. These routines allow users to enter a distribution of crystal orientations for calculation of total cross sections of user defined powder or pseudo powder distributions,more » which enables simulation of non-uniformities such as texture and strain. In conclusion, the spectra for neutron transmission simulations in the neutron thermal energy range (2 meV–100 meV) are presented for single crystal and polycrystal samples and compared to measurements.« less

Single crystal to polycrystal neutron transmission simulation

DOE PAGES

Dessieux, Luc Lucius; Stoica, Alexandru Dan; Bingham, Philip R.

2018-02-02

A collection of routines for calculation of the total cross section that determines the attenuation of neutrons by crystalline solids is presented. The total cross section is calculated semi-empirically as a function of crystal structure, neutron energy, temperature, and crystal orientation. The semi-empirical formula includes the contribution of parasitic Bragg scattering to the total cross section using both the crystal’s mosaic spread value and its orientation with respect to the neutron beam direction as parameters. These routines allow users to enter a distribution of crystal orientations for calculation of total cross sections of user defined powder or pseudo powder distributions,more » which enables simulation of non-uniformities such as texture and strain. In conclusion, the spectra for neutron transmission simulations in the neutron thermal energy range (2 meV–100 meV) are presented for single crystal and polycrystal samples and compared to measurements.« less

Elastolytic activity of sputum and its relation to purulence and to lung function in patients with bronchiectasis.

PubMed Central

Stockley, R A; Hill, S L; Morrison, H M; Starkie, C M

1984-01-01

Sputum samples from 34 patients with bronchiectasis were assessed subjectively and the results related to objective measurements of elastase activity and albumin content. The results suggest that the macroscopic appearance of the sample is related to the elastase content. 88.7% of the purulent samples but none of the mucoid samples showing elastase activity. The macroscopic appearance was also associated with changes in protein transudation into the secretions. The median sputum: serum albumin concentration ratio was 0.71 X 10(-2) (range 0.22-4.7) in the mucoid samples but was greater in purulent samples (p less than 0.005), with a median value of 1.52 X 10(-2) (range 0.55-12.72), suggesting that purulence in the stable state was associated with low grade pulmonary inflammation or epithelial damage or both. Abnormalities of air flow were found in 24 of the patients (70.6%) but there was a significantly higher ratio of residual volume to total lung capacity (p less than 0.025) in patients who regularly produced purulent sputum (mean (SD) RV/TLC 44.4% (9.0%] than in those with mucoid or mucopurulent secretions (38.0% (9.9%]. A similar difference was found between those who produced elastase positive secretions and those who produced elastase negative ones. PMID:6565423

Validity of histopathological grading of articular cartilage from osteoarthritic knee joints

PubMed Central

Ostergaard, K.; Andersen, C.; Petersen, J.; Bendtzen, K.; Salter, D.

1999-01-01

OBJECTIVES—To determine the validity of the histological-histochemical grading system (HHGS) for osteoarthritic (OA) articular cartilage.
METHODS—Human articular cartilage was obtained from macroscopically normal (n = 13) and OA (n = 21) knee joints. Sections of central and peripheral regions of normal samples were produced. Sections of regions containing severe, moderate, and mild OA changes were produced from each OA sample. A total of 89 sections were graded by means of the HHGS (0-14) twice by three observers.
RESULTS—Average scores for regions designated severe (8.64) and moderate (5.83) OA were less than the expected (10-14 and 6-9, respectively) according to the HHGS, whereas average scores for the region designated mild (5.29) OA and central and peripheral regions (2.19) of normal cartilage were higher than expected (2-5 and 0-1, respectively). The HHGS was capable of differentiating between articular cartilage from macroscopically normal and OA joints and between the region designated severe OA and other regions. However, the HHGS did not adequately differentiate between regions designated mild and moderate OA. Values for sensitivity, specificity, and efficiency for all regions varied considerably.
CONCLUSION—The HHGS is valid for normal and severe OA cartilage, but does not permit distinction between mild and moderate OA changes in articular cartilage.

 Keywords: histopathology; osteoarthritis; reliability; validity PMID:10364898

From Wood to Textiles: Top-Down Assembly of Aligned Cellulose Nanofibers.

PubMed

Jia, Chao; Chen, Chaoji; Kuang, Yudi; Fu, Kun; Wang, Yilin; Yao, Yonggang; Kronthal, Spencer; Hitz, Emily; Song, Jianwei; Xu, Fujun; Liu, Boyang; Hu, Liangbing

2018-06-07

Advanced textiles made of macroscopic fibers are usually prepared from synthetic fibers, which have changed lives over the past century. The shortage of petrochemical resources, however, greatly limits the development of the textile industry. Here, a facile top-down approach for fabricating macroscopic wood fibers for textile applications (wood-textile fibers) comprising aligned cellulose nanofibers directly from natural wood via delignification and subsequent twisting is demonstrated. Inherently aligned cellulose nanofibers are well retained, while the microchannels in the delignified wood are squeezed and totally removed by twisting, resulting in a dense structure with approximately two times higher mechanical strength (106.5 vs 54.9 MPa) and ≈20 times higher toughness (7.70 vs 0.36 MJ m -3 ) than natural wood. Dramatically different from natural wood, which is brittle in nature, the resultant wood-textile fibers are highly flexible and bendable, likely due to the twisted structures. The wood-textile fibers also exhibit excellent knitting properties and dyeability, which are critical for textile applications. Furthermore, functional wood-textile fibers can be achieved by preinfiltrating functional materials in the delignified wood film before twisting. This top-down approach of fabricating aligned macrofibers is simple, scalable, and cost-effective, representing a promising direction for the development of smart textiles and wearable electronics. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characterization of the anisotropic mechanical behavior of human abdominal wall connective tissues.

PubMed

Astruc, Laure; De Meulaere, Maurice; Witz, Jean-François; Nováček, Vit; Turquier, Frédéric; Hoc, Thierry; Brieu, Mathias

2018-06-01

Abdominal wall sheathing tissues are commonly involved in hernia formation. However, there is very limited work studying mechanics of all tissues from the same donor which prevents a complete understanding of the abdominal wall behavior and the differences in these tissues. The aim of this study was to investigate the differences between the mechanical properties of the linea alba and the anterior and posterior rectus sheaths from a macroscopic point of view. Eight full-thickness human anterior abdominal walls of both genders were collected and longitudinal and transverse samples were harvested from the three sheathing connective tissues. The total of 398 uniaxial tensile tests was conducted and the mechanical characteristics of the behavior (tangent rigidities for small and large deformations) were determined. Statistical comparisons highlighted heterogeneity and non-linearity in behavior of the three tissues under both small and large deformations. High anisotropy was observed under small and large deformations with higher stress in the transverse direction. Variabilities in the mechanical properties of the linea alba according to the gender and location were also identified. Finally, data dispersion correlated with microstructure revealed that macroscopic characterization is not sufficient to fully describe behavior. Microstructure consideration is needed. These results provide a better understanding of the mechanical behavior of the abdominal wall sheathing tissues as well as the directions for microstructure-based constitutive model. Copyright © 2018 Elsevier Ltd. All rights reserved.

Proton-Nucleus Total Cross Sections in Coupled-Channel Approach

NASA Technical Reports Server (NTRS)

Tripathi, R. K.; Wilson, John W.; Cucinotta, Francis A.

2000-01-01

Recently, nucleon-nucleon (N-N) cross sections in the medium have been extracted directly from experiment. The in-medium N-N cross sections form the basic ingredients of several heavy-ion scattering approaches including the coupled-channel approach developed at the Langley Research Center. In the present study the ratio of the real to the imaginary part of the two-body scattering amplitude in the medium was investigated. These ratios are used in combination with the in-medium N-N cross sections to calculate total proton-nucleus cross sections. The agreement is excellent with the available experimental data. These cross sections are needed for the radiation risk assessment of space missions.

Measurements of total production cross sections for $$\\pi^{+}$$+C, $$\\pi^{+}$$+Al, $$K^{+}$$+C, and $$K^{+}$$+Al at 60 GeV/c and $$\\pi^{+}$$+C and $$\\pi^{+}$$+Al at 31 GeV/c

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aduszkiewicz, A.; et al.

This paper presents several measurements of total production cross sections and total inelastic cross sections for the following reactions:more » $$\\pi^{+}$$+C, $$\\pi^{+}$$+Al, $$K^{+}$$+C, $$K^{+}$$+Al at 60 GeV/c, $$\\pi^{+}$$+C and $$\\pi^{+}$$+Al at 31 GeV/c . The measurements were made using the NA61/SHINE spectrometer at the CERN SPS. Comparisons with previous measurements are given and good agreement is seen. These interaction cross sections measurements are a key ingredient for neutrino flux prediction from the reinteractions of secondary hadrons in current and future accelerator-based long-baseline neutrino experiments.« less

Positron scattering from molecular hydrogen

NASA Astrophysics Data System (ADS)

Machacek, J. R.; Anderson, E. K.; Makochekanwa, C.; Buckman, S. J.; Sullivan, J. P.

2013-10-01

We present results for total and partial cross sections for positron scattering from H2. The total scattering and positronium formation cross sections are reported between 0.5 and 200 eV. Total quasielastic and inelastic scattering cross sections are reported for energies between the positronium formation threshold and 50 eV, with quasielastic differential scattering cross sections reported at 1, 3, 5, 7, and 10 eV. Our results are compared with previous work, both experimental and theoretical, with particular attention paid to the region below the positronium formation threshold, where there are apparent discrepancies in previous work. A discussion of possible reasons for discrepancies between this and previous work is presented, including a focus on known systematic effects in the experimental results.

Elevated temperature fracture of RS/PM alloy 8009; Part 1: Fracture mechanics behavior

DOE Office of Scientific and Technical Information (OSTI.GOV)

Porr, W.C. Jr.; Gangloff, R.P.

1994-02-01

Increasing temperature and decreasing loading rate degrade the planes strain initiation (K[sub ICi] from the J integral) and growth (tearing modulus, T[sub R]) fracture toughnesses of RS/PM 8009 (Al-8.5Fe-1.3V-1.7Si, wt pct). K[sub ICi] decreases with increasing temperature from 25[degree]C to 175[degree]C (33 to 15 MPa[radical]m at 316[degree]C) without a minimum. T[sub R] is greater than zero at all temperatures and is minimized at 200[degree]C. A four order-of-magnitude decrease in loading rate, at 175[degree]C, results in a 2.5-fold decrease in K[sub ICi] and a 5-fold reduction in T[sub R]. K[sub ICi] and T[sub R] are anisotropic for extruded 8009 but aremore » isotropic for cross-rolled plate. Cross rolling does not improve the magnitude or adverse temperature dependence of toughness. Delamination occurs along oxide-decorated particle boundaries for extruded but not cross-rolled 8009. Delamination toughening plays no role in the temperature dependence of K[sub ICi], however, T[sub R] is increased by this mechanism. Macroscopic work softening and flow localization do not occur for notch-root deformation; such uniaxial tensile phenomena may not be directly relevant to crack-tip fracture. Micromechanical modeling, employing temperature-dependent flow strength, modulus, and constrained fracture strain, reasonably predicts the temperature dependencies of K[sub ICi] and T[sub R] for 8009.« less

A new multigroup method for cross-sections that vary rapidly in energy

NASA Astrophysics Data System (ADS)

Haut, T. S.; Ahrens, C.; Jonko, A.; Lowrie, R.; Till, A.

2017-01-01

We present a numerical method for solving the time-independent thermal radiative transfer (TRT) equation or the neutron transport (NT) equation when the opacity (cross-section) varies rapidly in frequency (energy) on the microscale ε; ε corresponds to the characteristic spacing between absorption lines or resonances, and is much smaller than the macroscopic frequency (energy) variation of interest. The approach is based on a rigorous homogenization of the TRT/NT equation in the frequency (energy) variable. Discretization of the homogenized TRT/NT equation results in a multigroup-type system, and can therefore be solved by standard methods. We demonstrate the accuracy and efficiency of the approach on three model problems. First we consider the Elsasser band model with constant temperature and a line spacing ε =10-4 . Second, we consider a neutron transport application for fast neutrons incident on iron, where the characteristic resonance spacing ε necessitates ≈ 16 , 000 energy discretization parameters if Planck-weighted cross sections are used. Third, we consider an atmospheric TRT problem for an opacity corresponding to water vapor over a frequency range 1000-2000 cm-1, where we take 12 homogeneous layers between 1-15 km, and temperature/pressure values in each layer from the standard US atmosphere. For all three problems, we demonstrate that we can achieve between 0.1 and 1 percent relative error in the solution, and with several orders of magnitude fewer parameters than a standard multigroup formulation using Planck-weighted (source-weighted) opacities for a comparable accuracy.

Dipole response of neutron-rich Sn isotopes

NASA Astrophysics Data System (ADS)

Klimkiewicz, A.; Adrich, P.; Boretzky, K.; Fallot, M.; Aumann, T.; Cortina-Gil, D.; Datta Pramanik, U.; Elze, Th. W.; Emling, H.; Geissel, H.; Hellstroem, M.; Jones, K. L.; Kratz, J. V.; Kulessa, R.; Leifels, Y.; Nociforo, C.; Palit, R.; Simon, H.; Surowka, G.; Sümmerer, K.; Typel, S.; Walus, W.

2007-05-01

The neutron-rich isotopes 129-133Sn were studied in a Coulomb excitation experiment at about 500 AMeV using the FRS-LAND setup at GSI. From the exclusive measurement of all projectile-like particles following the excitation and decay of the projectile in a high-Z target, the energy differential cross section can be extracted. At these beam energies dipole transitions are dominating, and within the semi-classical approach the Coulomb excitation cross sections can be transformed into photoabsorption cross sections. In contrast to stable Sn nuclei, a substantial fraction of dipole strength is observed at energies below the giant dipole resonance (GDR). For 130Sn and 132Sn this strength is located in a peak-like structure around 10 MeV excitation energy and exhibits a few percent of the Thomas-Reiche Kuhn (TRK) sum-rule strength. Several calculations predict the appearance of dipole strength at low excitation energies in neutron-rich nuclei. This low-lying strength is often referred to as pygmy dipole resonance (PDR) and, in a macroscopic picture, is discussed in terms of a collective oscillation of excess neutrons versus the core nucleons. Moreover, a sharp rise is observed at the neutron separation threshold around 5 MeV for the odd isotopes. A possible contribution of 'threshold strength', which can be described within the direct-breakup model is discussed. The results for the neutron-rich Sn isotopes are confronted with results on stable nuclei investigated in experiments using real photons.

Hot spaghetti: Viscous gravitational collapse

NASA Astrophysics Data System (ADS)

Müller, Berndt; Schäfer, Andreas

2018-02-01

We explore the fate of matter falling into a macroscopic Schwarzschild black hole for the simplified case of a radially collapsing thin spherical shell for which the back reaction of the geometry can be neglected. We treat the internal dynamics of the in-falling matter in the framework of viscous relativistic hydrodynamics and calculate how the internal temperature of the collapsing matter evolves as it falls toward the Schwarzschild singularity. We find that viscous hydrodynamics fails when either the dissipative radial pressure exceeds the thermal pressure and the total radial pressure becomes negative, or the time scale of variation of the tidal forces acting on the collapsing matter becomes shorter than the characteristic hydrodynamic response time.

Magnetohydrodynamic (MHD) analyses of various forms of activity and their propagation through helio spheric space

NASA Technical Reports Server (NTRS)

Wu, S. T.

1987-01-01

Theoretical and numerical modeling of solar activity and its effects on the solar atmosphere within the context of magnetohydrodynamics were examined. Specifically, the scientific objectives were concerned with the physical mechanisms for the flare energy build-up and subsequent release. In addition, transport of this energy to the corona and solar wind was also investigated. Well-posed, physically self-consistent, numerical simulation models that are based upon magnetohydrodynamics were sought. A systematic investigation of the basic processes that determine the macroscopic dynamic behavior of solar and heliospheric phenomena was conducted. A total of twenty-three articles were accepted and published in major journals. The major achievements are summarized.

A new compilation of experimental nuclear data for total reaction cross sections

NASA Astrophysics Data System (ADS)

Lantz, Mattias; Sihver, L.

The nucleon-nucleus and nucleus-nucleus total reaction cross sections are of importance in many different fields, both for a better theoretical understanding as well as for a number of applications, including space radiation dosimetry. We have performed a comprehensive literature study in order to find all available experimental data on total reaction cross sections, σR , and interaction cross sections, σI , for neutrons, protons, and all stable and exotic heavy ions. Excluded from the data base are measurements where the cross sections have been derived through model-dependent calculations from other kinds of measurements. The objective of the study is to identify where more measurements are needed in view of different applications, and to make the data easily available for model developers and experimentalists. We will present some examples from the study, which is in the stage of quality control of all the gathered data.

Total cross sections for ultracold neutrons scattered from gases

DOE PAGES

Seestrom, Susan Joyce; Adamek, Evan R.; Barlow, Dave; ...

2017-01-30

Here, we have followed up on our previous measurements of upscattering of ultracold neutrons (UCNs) from a series of gases by making measurements of total cross sections on the following gases hydrogen, ethane, methane, isobutene, n-butane, ethylene, water vapor, propane, neopentane, isopropyl alcohol, and 3He. The values of these cross sections are important for estimating the loss rate of trapped neutrons due to residual gas and are relevant to neutron lifetime measurements using UCNs. The effects of the UCN velocity and path-length distributions were accounted for in the analysis using a Monte Carlo transport code. Results are compared to ourmore » previous measurements and with the known absorption cross section for 3He scaled to our UCN energy. We find that the total cross sections for the hydrocarbon gases are reasonably described by a function linear in the number of hydrogen atoms in the molecule.« less

Validation of Cross Sections for Monte Carlo Simulation of the Photoelectric Effect

NASA Astrophysics Data System (ADS)

Han, Min Cheol; Kim, Han Sung; Pia, Maria Grazia; Basaglia, Tullio; Batič, Matej; Hoff, Gabriela; Kim, Chan Hyeong; Saracco, Paolo

2016-04-01

Several total and partial photoionization cross section calculations, based on both theoretical and empirical approaches, are quantitatively evaluated with statistical analyses using a large collection of experimental data retrieved from the literature to identify the state of the art for modeling the photoelectric effect in Monte Carlo particle transport. Some of the examined cross section models are available in general purpose Monte Carlo systems, while others have been implemented and subjected to validation tests for the first time to estimate whether they could improve the accuracy of particle transport codes. The validation process identifies Scofield's 1973 non-relativistic calculations, tabulated in the Evaluated Photon Data Library (EPDL), as the one best reproducing experimental measurements of total cross sections. Specialized total cross section models, some of which derive from more recent calculations, do not provide significant improvements. Scofield's non-relativistic calculations are not surpassed regarding the compatibility with experiment of K and L shell photoionization cross sections either, although in a few test cases Ebel's parameterization produces more accurate results close to absorption edges. Modifications to Biggs and Lighthill's parameterization implemented in Geant4 significantly reduce the accuracy of total cross sections at low energies with respect to its original formulation. The scarcity of suitable experimental data hinders a similar extensive analysis for the simulation of the photoelectron angular distribution, which is limited to a qualitative appraisal.

Defining the macroscopic and microscopic findings of experimental focal brain ischemia in rats from a forensic scientist's point of view.

PubMed

Tatlisumak, Ertugrul; Inan, Sevinc; Asirdizer, Mahmut; Apaydin, Nihal; Hayretdag, Ceyda; Kose, Can; Tekdemir, Ibrahim

2009-03-01

Approximately 10% of all deaths in the world occur as a result of stroke. Determination of the time schedule of the pathologic events in a stroke patient is invaluable for a forensic specialist. The aim of this study was to define the schedule of the macroscopic and microscopic changes that occurred in a rat model of permanent focal ischemia for providing useful clues for the evaluation of stroke patients. Male Wistar rats weighing 250 to 350 g were used in this study. Permanent focal brain ischemia was applied by the suture occlusion method. The animals were divided into 7 experimental groups (n = 6) with time schedules including 1.5, 3, 6, 12, 24, 72 hours, and the sham. Brains were harvested at the end of the determined time schedule. Lesions in the frontoparietal cortex were evaluated macroscopically first and later hematoxylin eosin stained sections from the infarct core were investigated microscopically. Macroscopically, enlargement of the ipsilateral hemisphere was mild at 6 hour, apparent at 12 and 24 hours, and mild again at 72 hours. Microscopically, ischemic changes were apparent even at 1.5 hour. Red neurons and infiltration of the parenchyma with neutrophil leukocytes were observed at 12 hours. Pannecrosis and massive leukocyte infiltration were observed at 72 hours. Macroscopic and microscopic findings obtained from a rat model may provide clues for determination of the time-dependent changes due to brain ischemia in human subjects. Finally, the benefits of determination of time course of pathologic changes in the brain for forensic scientists were discussed.

A semi-empirical model relating micro structure to acoustic properties of bimodal porous material

NASA Astrophysics Data System (ADS)

Mosanenzadeh, Shahrzad Ghaffari; Doutres, Olivier; Naguib, Hani E.; Park, Chul B.; Atalla, Noureddine

2015-01-01

Complex morphology of open cell porous media makes it difficult to link microstructural parameters and acoustic behavior of these materials. While morphology determines the overall sound absorption and noise damping effectiveness of a porous structure, little is known on the influence of microstructural configuration on the macroscopic properties. In the present research, a novel bimodal porous structure was designed and developed solely for modeling purposes. For the developed porous structure, it is possible to have direct control on morphological parameters and avoid complications raised by intricate pore geometries. A semi-empirical model is developed to relate microstructural parameters to macroscopic characteristics of porous material using precise characterization results based on the designed bimodal porous structures. This model specifically links macroscopic parameters including static airflow resistivity ( σ ) , thermal characteristic length ( Λ ' ) , viscous characteristic length ( Λ ) , and dynamic tortuosity ( α ∞ ) to microstructural factors such as cell wall thickness ( 2 t ) and reticulation rate ( R w ) . The developed model makes it possible to design the morphology of porous media to achieve optimum sound absorption performance based on the application in hand. This study makes the base for understanding the role of microstructural geometry and morphological factors on the overall macroscopic parameters of porous materials specifically for acoustic capabilities. The next step is to include other microstructural parameters as well to generalize the developed model. In the present paper, pore size was kept constant for eight categories of bimodal foams to study the effect of secondary porous structure on macroscopic properties and overall acoustic behavior of porous media.

Hybrid Multiscale Finite Volume Method for Advection-Diffusion Equations Subject to Heterogeneous Reactive Boundary Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barajas-Solano, David A.; Tartakovsky, A. M.

2016-10-13

We present a hybrid scheme for the coupling of macro and microscale continuum models for reactive contaminant transport in fractured and porous media. The transport model considered is the advection-dispersion equation, subject to linear heterogeneous reactive boundary conditions. The Multiscale Finite Volume method (MsFV) is employed to define an approximation to the microscale concentration field defined in terms of macroscopic or \\emph{global} degrees of freedom, together with local interpolator and corrector functions capturing microscopic spatial variability. The macroscopic mass balance relations for the MsFV global degrees of freedom are coupled with the macroscopic model, resulting in a global problem for the simultaneous time-stepping of all macroscopic degrees of freedom throughout the domain. In order to perform the hybrid coupling, the micro and macroscale models are applied over overlapping subdomains of the simulation domain, with the overlap denoted as the handshake subdomainmore » $$\\Omega^{hs}$$, over which continuity of concentration and transport fluxes between models is enforced. Continuity of concentration is enforced by posing a restriction relation between models over $$\\Omega^{hs}$$. Continuity of fluxes is enforced by prolongating the macroscopic model fluxes across the boundary of $$\\Omega^{hs}$$ to microscopic resolution. The microscopic interpolator and corrector functions are solutions to local microscopic advection-diffusion problems decoupled from the global degrees of freedom and from each other by virtue of the MsFV decoupling ansatz. The error introduced by the decoupling ansatz is reduced iteratively by the preconditioned GMRES algorithm, with the hybrid MsFV operator serving as the preconditioner.« less

Temperature-induced sol-gel transition and microgel formation in α-actinin cross-linked actin networks: A rheological study

NASA Astrophysics Data System (ADS)

Tempel, M.; Isenberg, G.; Sackmann, E.

1996-08-01

We have studied the sol-gel transition, the viscoelastic and the structural properties of networks constituted of semiflexible actin filaments cross-linked by α-actinin. Cross-linking was regulated in a reversible way by varying the temperature through the association-dissociation equilibrium of the actin-α-actinin system. Viscoelastic parameters [shear storage modulus G'(ω), phase shift tan(Φ)(ω), creep compliance J(t)] were measured as a function of temperature and actin-to-cross-linker ratio by a magnetically driven rotating disc rheometer. G'(ω) and tan(Φ)(ω) were studied at a frequency ω corresponding to the elastic plateau regime of the G'(ω) versus ω spectrum of the purely entangled solution. The microstructure of the networks was viewed by negative staining electron microscopy (EM). The phase shift tan(Φ) (or equivalently the viscosity η) diverges and reaches a maximum when approaching the apparent gel point from lower and higher temperatures, and the maximum defines the gel point (temperature Tg). The elastic plateau modulus G'N diverges at temperatures beyond this gel point TTg. The cross-linking transition (corresponding to a sol-gel transition at zero frequency) is interpreted in terms of a percolation model and the divergence of G'N at TTg), (2) that microscopic segregation takes place at T<=Tg leading to local formation of clusters (a state termed microgel), and (3) that at low actin-α-actinin ratios (rAα<=10) and low temperatures (T<=10 °C) macroscopic segregation into bundles of cross-linked actin filaments and a diluted solution of actin filaments is observed. The three regimes of network structure are represented by an equivalent phase diagram.

Two Simple Classroom Demonstrations for Scanning Probe Microscopy Based on a Macroscopic Analogy

ERIC Educational Resources Information Center

Hajkova, Zdenka; Fejfar, Antonin; Smejkal, Petr

2013-01-01

This article describes two simple classroom demonstrations that illustrate the principles of scanning probe microscopy (SPM) based on a macroscopic analogy. The analogy features the bumps in an egg carton to represent the atoms on a chemical surface and a probe that can be represented by a dwarf statue (illustrating an origin of the prefix…

On representation of mechanical behavior and stereological measures of microstructure

NASA Technical Reports Server (NTRS)

Onat, E. T.; Wright, S. I.

1991-01-01

Macroscopic homogeneity of a heterogeneous body is defined from various points of view. The applicability of the principle of Delesse to a single macroscopically homogeneous body is discussed. It is then seen that a function derived from a consideration of the area fraction of a phase can serve as a measure of clustering of particles of that phase.

Charge of a macroscopic particle in a plasma sheath.

PubMed

Samarian, A A; Vladimirov, S V

2003-06-01

Charging of a macroscopic body levitating in a rf plasma sheath is studied experimentally and theoretically. The nonlinear charge vs size dependence is obtained. The observed nonlinearity is explained on the basis of an approach taking into account different plasma conditions for the levitation positions of different particles. The importance of suprathermal electrons' contribution to the charging process is demonstrated.

The Search for Life on Mars Using Macroscopically Visible Microbial Mats (Stromatolites) in 3.5 3.3 Ga Cherts from the Pilbara in Australia and Barberton in South Africa as Analogues

NASA Astrophysics Data System (ADS)

Westall, F.; Hofmann, B.; Brack, A.

2004-03-01

Microbial mats from early terrestrial environments can be macroscopically visible and represent excellent analogues in the search for life on Mars. Tests using the Beagle 2 camera show that they can be observed by in situ instrumentation.

PLACENTA OF THE INDIAN ELEPHANT, ELEPHAS INDICUS.

PubMed

COOPER, R A; CONNELL, R S; WELLINGS, S R

1964-10-16

The placenta of the Indian elephant is incompletely annular and zonary macroscopically and occupies the equator of an ovoid chorioallantoic sac. The amnion is fused with the chorion over the zone. Microscopically, the placenta is labyrinthine and endotheliochorial with a rudimentary marginal hematoma. Both macroscopically and microscopically it resembles the placentas of thecarnivores, particularly the racoon, the cat, and the dog.

Micro-CT based finite element models for elastic properties of glass-ceramic scaffolds.

PubMed

Tagliabue, Stefano; Rossi, Erica; Baino, Francesco; Vitale-Brovarone, Chiara; Gastaldi, Dario; Vena, Pasquale

2017-01-01

In this study, the mechanical properties of porous glass-ceramic scaffolds are investigated by means of three-dimensional finite element models based on micro-computed tomography (micro-CT) scan data. In particular, the quantitative relationship between the morpho-architectural features of the obtained scaffolds, such as macroscopic porosity and strut thickness, and elastic properties, is sought. The macroscopic elastic properties of the scaffolds have been obtained through numerical homogenization approaches using the mechanical characteristics of the solid walls of the scaffolds (assessed through nanoindentation) as input parameters for the numerical simulations. Anisotropic mechanical properties of the produced scaffolds have also been investigated by defining a suitable anisotropy index. A comparison with morphological data obtained through the micro-CT scans is also presented. The proposed study shows that the produced glass-ceramic scaffolds exhibited a macroscopic porosity ranging between 29% and 97% which corresponds to an average stiffness ranging between 42.4GPa and 36MPa. A quantitative estimation of the isotropy of the macroscopic elastic properties has been performed showing that the samples with higher solid fractions were those closest to an isotropic material. Copyright © 2016 Elsevier Ltd. All rights reserved.

Modélisation macroscopique des milieux stratifiés conducteurs

NASA Astrophysics Data System (ADS)

Matagne, E.; Conard, J. Ph.

1997-11-01

Many laminated structures are recognised in Electrotechnics : magnetic cores, flat conductors windings, slotted surfaces... These structures exhibit macroscopic properties, as magnetic than electric ones. This paper shows how these characteristics can be obtained by homogenisation. It deals with linear materials but taking into account the effect of eddy currents, as well on the macroscopic magnetic permeability as on the macroscopic electric conductivity, which become then complex numbers. An example of use of the macroscopic properties is provided. On peut identifier en électrotechnique de nombreuses structures stratifiées: noyaux magnétiques, bobinages formés de conducteurs plats, surfaces encochées... Ces structures présentent des propriétés macroscopiques tant magnétiques qu'électriques. Cet article montre comment ces caractéristiques peuvent être obtenues par homogénéisation. Il se limite au cas de matériaux linéaires mais en prenant en compte l'effet des courants de Foucault aussi bien sur la perméabilité magnétique macroscopique que sur la conductivité électrique macroscopique, grandeurs qui deviennent alors des nombres complexes. Un exemple d'utilisation des caractéristiques macroscopiques est fourni.

Concealing with structured light.

PubMed

Sun, Jingbo; Zeng, Jinwei; Wang, Xi; Cartwright, Alexander N; Litchinitser, Natalia M

2014-02-13

While making objects less visible (or invisible) to a human eye or a radar has captured people's imagination for centuries, current attempts towards realization of this long-awaited functionality range from various stealth technologies to recently proposed cloaking devices. A majority of proposed approaches share a number of common deficiencies such as design complexity, polarization effects, bandwidth, losses and the physical size or shape requirement complicating their implementation especially at optical frequencies. Here we demonstrate an alternative way to conceal macroscopic objects by structuring light itself. In our approach, the incident light is transformed into an optical vortex with a dark core that can be used to conceal macroscopic objects. Once such a beam passed around the object it is transformed back into its initial Gaussian shape with minimum amplitude and phase distortions. Therefore, we propose to use that dark core of the vortex beam to conceal an object that is macroscopic yet small enough to fit the dark (negligibly low intensity) region of the beam. The proposed concealing approach is polarization independent, easy to fabricate, lossless, operates at wavelengths ranging from 560 to 700 nm, and can be used to hide macroscopic objects providing they are smaller than vortex core.

Sialic Acid-Responsive Polymeric Interface Material: From Molecular Recognition to Macroscopic Property Switching

NASA Astrophysics Data System (ADS)

Xiong, Yuting; Jiang, Ge; Li, Minmin; Qing, Guangyan; Li, Xiuling; Liang, Xinmiao; Sun, Taolei

2017-01-01

Biological systems that utilize multiple weak non-covalent interactions and hierarchical assemblies to achieve various bio-functions bring much inspiration for the design of artificial biomaterials. However, it remains a big challenge to correlate underlying biomolecule interactions with macroscopic level of materials, for example, recognizing such weak interaction, further transforming it into regulating material’s macroscopic property and contributing to some new bio-applications. Here we designed a novel smart polymer based on polyacrylamide (PAM) grafted with lactose units (PAM-g-lactose0.11), and reported carbohydrate-carbohydrate interaction (CCI)-promoted macroscopic properties switching on this smart polymer surface. Detailed investigations indicated that the binding of sialic acid molecules with the grafted lactose units via the CCIs induced conformational transformation of the polymer chains, further resulted in remarkable and reversible switching in surface topography, wettability and stiffness. With these excellent recognition and response capacities towards sialic acid, the PAM-g-lactose0.11 further facilitated good selectivity, strong anti-interference and high adsorption capacity in the capture of sialylated glycopeptides (important biomarkers for cancers). This work provides some enlightenment for the development of biointerface materials with tunable property, as well as high-performance glycopeptide enrichment materials.

Magnetic properties and macroscopic heterogeneity of FeCoNbB Hitperms

NASA Astrophysics Data System (ADS)

Butvin, Pavol; Butvinová, Beata; Sitek, Jozef; Degmová, Jarmila; Vlasák, Gabriel; Švec, Peter; Janičkovič, Dušan

Nanocrystalline ribbons of Fe 81-xCo xNb 7B 12 (where x ranges from 0 to 40.5 at%) Hitperm alloys have been investigated as to their basic magnetic properties and the influence of the macroscopic heterogeneity. Different crystalline share at surfaces compared with the volume average is observed by conversion electron Mössbauer spectroscopy (CEMS) and Mössbauer spectroscopy (MS), respectively. This marks the presence of macroscopic heterogeneity in these Hitperms. The heterogeneity is generally more significant in Ar-annealed samples than in the vacuum-annealed ones. The characteristic slant hysteresis loops (hard-ribbon-axis) are seen as a rule with few exceptions. An inspection of hysteresis loop response of resin potted samples shows that the surfaces bi-axially squeeze the ribbon interior in heterogeneous Hitperms when the ribbons cool down after annealing. Certain compositions show macroscopic viscous flow prior to crystallization so the heterogeneity gets another chance to induce anisotropy during annealing. The induction attains 1.5 T but saturates poorly due to the heterogeneity and the ensuing anisotropy. Moreover the heterogeneity appears to hamper the crystallization within the ribbon interior. Unlike Finemets, the density of these Hitperms show no pronounced trend with annealing.

Coherent coupling of a superconducting flux qubit to an electron spin ensemble in diamond.

PubMed

Zhu, Xiaobo; Saito, Shiro; Kemp, Alexander; Kakuyanagi, Kosuke; Karimoto, Shin-ichi; Nakano, Hayato; Munro, William J; Tokura, Yasuhiro; Everitt, Mark S; Nemoto, Kae; Kasu, Makoto; Mizuochi, Norikazu; Semba, Kouichi

2011-10-12

During the past decade, research into superconducting quantum bits (qubits) based on Josephson junctions has made rapid progress. Many foundational experiments have been performed, and superconducting qubits are now considered one of the most promising systems for quantum information processing. However, the experimentally reported coherence times are likely to be insufficient for future large-scale quantum computation. A natural solution to this problem is a dedicated engineered quantum memory based on atomic and molecular systems. The question of whether coherent quantum coupling is possible between such natural systems and a single macroscopic artificial atom has attracted considerable attention since the first demonstration of macroscopic quantum coherence in Josephson junction circuits. Here we report evidence of coherent strong coupling between a single macroscopic superconducting artificial atom (a flux qubit) and an ensemble of electron spins in the form of nitrogen-vacancy colour centres in diamond. Furthermore, we have observed coherent exchange of a single quantum of energy between a flux qubit and a macroscopic ensemble consisting of about 3 × 10(7) such colour centres. This provides a foundation for future quantum memories and hybrid devices coupling microwave and optical systems.

Inferring Spatial Variations of Microstructural Properties from Macroscopic Mechanical Response

PubMed Central

Liu, Tengxiao; Hall, Timothy J.; Barbone, Paul E.; Oberai, Assad A.

2016-01-01

Disease alters tissue microstructure, which in turn affects the macroscopic mechanical properties of tissue. In elasticity imaging, the macroscopic response is measured and is used to infer the spatial distribution of the elastic constitutive parameters. When an empirical constitutive model is used these parameters cannot be linked to the microstructure. However, when the constitutive model is derived from a microstructural representation of the material, it allows for the possibility of inferring the local averages of the spatial distribution of the microstructural parameters. This idea forms the basis of this study. In particular, we first derive a constitutive model by homogenizing the mechanical response of a network of elastic, tortuous fibers. Thereafter, we use this model in an inverse problem to determine the spatial distribution of the microstructural parameters. We solve the inverse problem as a constrained minimization problem, and develop efficient methods for solving it. We apply these methods to displacement fields obtained by deforming gelatin-agar co-gels, and determine the spatial distribution of agar concentration and fiber tortuosity, thereby demonstrating that it is possible to image local averages of microstructural parameters from macroscopic measurements of deformation. PMID:27655420

Implementing Total Quality Management in a University Setting.

ERIC Educational Resources Information Center

Coate, L. Edwin

1991-01-01

Oregon State University implemented Total Quality Management in nine phases: exploration; establishing a pilot study team; defining customer needs; adopting the breakthrough planning process; performing breakthrough planning in divisions; forming daily management teams; initiating cross-functional pilot projects; implementing cross-functional…

Variation in Differential and Total Cross Sections Due to Different Radial Wave Functions

ERIC Educational Resources Information Center

Williamson, W., Jr.; Greene, T.

1976-01-01

Three sets of analytical wave functions are used to calculate the Na (3s---3p) transition differential and total electron excitation cross sections by Born approximations. Results show expected large variations in values. (Author/CP)

Total electron scattering cross sections of some important biomolecules at 0.2-6.0 keV energies

NASA Astrophysics Data System (ADS)

Gurung, Meera Devi; Ariyasinghe, W. M.

2017-12-01

The total electron scattering cross sections (TCS) of five nucleic bases (adenine, cytosine, guanine, thymine and uracil), phosphoric acid, three amino acids (glycine, lysine, and L-histidine), D-glucose, alpha-D-glucose, tetrahydropyran (THP), 3-hydroxytetrahydrofuran and furan have been determined in the energy range 0.2-6.0 keV using a simple model based on the effective atomic total electron scattering cross sections (EATCS). The reliability of the model is confirmed by comparing the determined TCS with the predictions of those by existing theoretical models.

Total photoproduction cross section measurement at HERA energies

NASA Astrophysics Data System (ADS)

Ahmed, T.; Andreev, V.; Andrieu, B.; Arpagaus, M.; Babaev, A.; Bärwolff, H.; Bán, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Bassler, U.; Beck, G. A.; Beck, H. P.; Behrend, H.-J.; Belousov, A.; Berger, Ch.; Bergstein, H.; Bernardi, G.; Bernet, R.; Berthon, U.; Bertrand-Coremans, G.; Besançon, M.; Biddulph, P.; Binder, E.; Bizot, J. C.; Blobel, V.; Borras, K.; Bosetti, P. C.; Boudry, V.; Bourdarios, C.; Brasse, F.; Braun, U.; Braunschweig, W.; Brisson, V.; Bruncko, D.; Bürger, J.; Büsser, F. W.; Buniatian, A.; Burke, S.; Buschhorn, G.; Campbell, A. J.; Carli, T.; Charles, F.; Clarke, D.; Clegg, A. B.; Colombo, M.; Coughlan, J. A.; Courau, A.; Coutures, Ch.; Cozzika, G.; Criegee, L.; Cvach, J.; Dainton, J. B.; Danilov, M.; Dann, A. W. E.; Dau, W. D.; David, M.; Deffur, E.; Delcourt, B.; del Buono, L.; Devel, M.; de Roeck, A.; Dingus, P.; Dollfus, C.; Dowell, J. D.; Dreis, H. B.; Drescher, A.; Duboc, J.; Düllmann, D.; Dünger, O.; Duhm, H.; Eberle, M.; Ebert, J.; Ebert, T. R.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eichenberger, S.; Eichler, R.; Eisele, F.; Eisenhandler, E.; Ellis, N. N.; Ellison, R. J.; Elsen, E.; Erdmann, M.; Evrard, E.; Favart, L.; Fedotov, A.; Feeken, D.; Felst, R.; Feltesse, J.; Feng, Y.; Fensome, I. F.; Ferencei, J.; Ferrarotto, F.; Flauger, W.; Fleischer, M.; Flower, P. S.; Flügge, G.; Fomenko, A.; Fominykh, B.; Forbush, M.; Formánek, J.; Foster, J. M.; Franke, G.; Fretwurst, E.; Fuhrmann, P.; Gabathuler, E.; Gamerdinger, K.; Garvey, J.; Gayler, J.; Gellrich, A.; Gennis, M.; Gensch, U.; Genzel, H.; Gerhards, R.; Gillespie, D.; Godfrey, L.; Goerlach, U.; Goerlich, L.; Goldberg, M.; Goodall, A. M.; Gorelov, I.; Goritchev, P.; Grab, C.; Grässler, H.; Grässler, R.; Greenshaw, T.; Greif, H.; Grindhammer, G.; Gruber, C.; Haack, J.; Haidt, D.; Hajduk, L.; Hamon, O.; Handschuh, D.; Hanlon, E. M.; Hapke, M.; Harjes, J.; Hartz, P.; Haydar, R.; Haynes, W. J.; Heatherington, J.; Hedberg, V.; Hedgecock, R.; Heinzelmann, G.; Henderson, R. C. W.; Henschel, H.; Herma, R.; Herynek, I.; Hildesheim, W.; Hill, P.; Hilton, C. D.; Hladký, J.; Hoeger, K. C.; Huet, Ph.; Hufnagel, H.; Huot, N.; Ibbotson, M.; Jabiol, M. A.; Jacholkowska, A.; Jacobsson, C.; Jaffre, M.; Jönsson, L.; Johannsen, K.; Johnson, D. P.; Johnson, L.; Jung, H.; Kalmus, P. I. P.; Kasarian, S.; Kaschowitz, R.; Kasselmann, P.; Kathage, U.; Kaufmann, H. H.; Kenyon, I. R.; Kermiche, S.; Kiesling, C.; Klein, M.; Kleinwort, C.; Knies, G.; Köhler, T.; Kolanoski, H.; Kole, F.; Kolya, S. D.; Korbel, V.; Korn, M.; Kostka, P.; Kotelnikov, S. K.; Krasny, M. W.; Krehbiel, H.; Krücker, D.; Krüger, U.; Kubenka, J. P.; Küster, H.; Kuhlen, M.; Kurça, T.; Kurzhöfer, J.; Kuznik, B.; Lander, R.; Landon, M. P. J.; Langkau, R.; Lanius, P.; Laporte, J. F.; Lebedev, A.; Leuschner, A.; Leverenz, C.; Levin, D.; Levonian, S.; Ley, Ch.; Lindner, A.; Lindström, G.; Loch, P.; Lohmander, H.; Lopez, G. C.; Lüers, D.; Magnussen, N.; Malinovski, E.; Mani, S.; Marage, P.; Marks, J.; Marshall, R.; Martens, J.; Martin, R.; Martyn, H.-U.; Martyniak, J.; Masson, S.; Mavroidis, A.; Maxfield, S. J.; McMahon, S. J.; Mehta, A.; Meier, K.; Merz, T.; Meyer, C. A.; Meyer, H.; Meyer, J.; Mikocki, S.; Milone, V.; Monnier, E.; Moreau, F.; Moreels, J.; Morris, J. V.; Morton, J. M.; Müller, K.; Murín, P.; Murray, S. A.; Nagovizin, V.; Naroska, B.; Naumann, Th.; Newton, D.; Nguyen, H. K.; Niebergall, F.; Nisius, R.; Nowak, G.; Noyes, G. W.; Nyberg, M.; Oberlack, H.; Obrock, H.; Olsson, J. E.; Orenstein, S.; Ould-Saada, F.; Pascaud, C.; Patel, G. D.; Peppel, E.; Peters, S.; Phillips, H. T.; Phillips, J. P.; Pichler, Ch.; Pilgram, W.; Pitzl, D.; Prosi, R.; Raupach, F.; Rauschnabel, K.; Reimer, P.; Ribarics, P.; Riech, V.; Riedlberger, J.; Rietz, M.; Robertson, S. M.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Royon, C.; Rudowicz, M.; Ruffer, M.; Rusakov, S.; Rybicki, K.; Ryseck, E.; Sacton, J.; Sahlmann, N.; Sanchez, E.; Sankey, D. P. C.; Savitsky, M.; Schacht, P.; Schleper, P.; von Schlippe, W.; Schmidt, C.; Schmidt, D.; Schmitz, W.; Schröder, V.; Schulz, M.; Schwind, A.; Scobel, W.; Seehausen, U.; Sell, R.; Seman, M.; Semenov, A.; Shekelyan, V.; Sheviakov, I.; Shooshtari, H.; Siegmon, G.; Siewert, U.; Sirois, Y.; Skillicorn, I. O.; Smirnov, P.; Smith, J. R.; Smolik, L.; Soloviev, Y.; Spitzer, H.; Staroba, P.; Steenbock, M.; Steffen, P.; Steinberg, R.; Steiner, H.; Stella, B.; Stephens, K.; Stier, J.; Strachota, J.; Straumann, U.; Struczinski, W.; Sutton, J. P.; Taylor, R. E.; Thompson, G.; Thompson, R. J.; Tichomirov, I.; Trenkel, C.; Truöl, P.; Tchernyshov, V.; Turnau, J.; Tutas, J.; Urban, L.; Usik, A.; Valkar, S.; Valkarova, A.; Vallee, C.; van Esch, P.; Vartapetian, A.; Vazdik, Y.; Vecko, M.; Verrecchia, P.; Vick, R.; Villet, G.; Vogel, E.; Wacker, K.; Walker, I. W.; Walther, A.; Weber, G.; Wegener, D.; Wegner, A.; Wellisch, H. P.; Willard, S.; Winde, M.; Winter, G.-G.; Wolff, Th.; Womersley, L. A.; Wright, A. E.; Wulff, N.; Yiou, T. P.; Áçek, J.; Závada, P.; Zeitnitz, C.; Ziaeepour, H.; Zimmer, M.; Zimmermann, W.; Zomer, F.

1993-01-01

We present first results on the total photoproduction cross section measurement with the H1 detector at HERA. The data were extracted from low Q2 collisions of 26.7 GeV electrons with 820 GeV protons. The γp total cross section has been measured by two independent methods in the γp center of mass energy range from 90 to 290 GeV. For an average center of mass energy of 195 GeV a value of σtot (γp) = 159 +/- 7 (stat.) +/- 20 (syst.) μb was obtained. Supported by the Swedish Natural Science Research Council.

Cross-linked polyethylene does not reduce wear in total knee arthroplasty.

PubMed

Lasurt-Bachs, S; Torner, P; Maculé, F; Prats, E; Menéndez-García, F; Ríos-Guillermo, J; Torrents, A

To compare two different types of inserts: Ultra-high molecular weight polyethylene (UHMWPE) and cross-linked polyethylene with a quantitative and qualitative study of polyethylene wear particles in synovial fluid 3 years after total knee arthroplasty. A prospective, randomized, controlled cohort study with blinded evaluation was carried out on 25 patients undergoing staged bilateral total knee replacement, 6 months apart. Knee arthrocentesis was performed on 12 patients 3 years after surgery, and the polyethylene particles were analyzed. No significant differences were found in the number of particles generated by the two different types of inserts at 3 years from total knee arthroplasty (3,000×: x¯ cross-linked=849.7; x¯ UHMWPE=796.9; P=.63; 20,000×: x¯ cross-linked=66.3; x¯ UHMWPE=73.1; P=.76). Likewise, no differences in the probability of finding elongated (χ 2 =0.19; P=.66) or rounded (χ 2 =1.44; P=.23) particles in both types of inserts were observed. However, the probability of finding fibrillar particles is 3.08 times greater in UHMWPE. Cross-linked polyethylene does not significantly reduce the generation of polyethylene particles in patients with total knee arthroplasty, 3 years after the surgical procedure. Copyright © 2018 SECOT. Publicado por Elsevier España, S.L.U. All rights reserved.

Diffusion phenomena of cells and biomolecules in microfluidic devices.

PubMed

Yildiz-Ozturk, Ece; Yesil-Celiktas, Ozlem

2015-09-01

Biomicrofluidics is an emerging field at the cross roads of microfluidics and life sciences which requires intensive research efforts in terms of introducing appropriate designs, production techniques, and analysis. The ultimate goal is to deliver innovative and cost-effective microfluidic devices to biotech, biomedical, and pharmaceutical industries. Therefore, creating an in-depth understanding of the transport phenomena of cells and biomolecules becomes vital and concurrently poses significant challenges. The present article outlines the recent advancements in diffusion phenomena of cells and biomolecules by highlighting transport principles from an engineering perspective, cell responses in microfluidic devices with emphases on diffusion- and flow-based microfluidic gradient platforms, macroscopic and microscopic approaches for investigating the diffusion phenomena of biomolecules, microfluidic platforms for the delivery of these molecules, as well as the state of the art in biological applications of mammalian cell responses and diffusion of biomolecules.

Tuning and Freezing Disorder in Photonic Crystals using Percolation Lithography.

PubMed

Burgess, Ian B; Abedzadeh, Navid; Kay, Theresa M; Shneidman, Anna V; Cranshaw, Derek J; Lončar, Marko; Aizenberg, Joanna

2016-01-21

Although common in biological systems, synthetic self-assembly routes to complex 3D photonic structures with tailored degrees of disorder remain elusive. Here we show how liquids can be used to finely control disorder in porous 3D photonic crystals, leading to complex and hierarchical geometries. In these optofluidic crystals, dynamically tunable disorder is superimposed onto the periodic optical structure through partial wetting or evaporation. In both cases, macroscopic symmetry breaking is driven by subtle sub-wavelength variations in the pore geometry. These variations direct site-selective infiltration of liquids through capillary interactions. Incorporating cross-linkable resins into our liquids, we developed methods to freeze in place the filling patterns at arbitrary degrees of partial wetting and intermediate stages of drying. These percolation lithography techniques produced permanent photonic structures with adjustable disorder. By coupling strong changes in optical properties to subtle differences in fluid behavior, optofluidic crystals may also prove useful in rapid analysis of liquids.

Density-transition scale at quasiperpendicular collisionless shocks.

PubMed

Bale, S D; Mozer, F S; Horbury, T S

2003-12-31

Measurements of a spacecraft floating potential, on the four Cluster spacecraft, are used as a proxy for electron plasma density to study, for the first time, the macroscopic density transition scale at 98 crossings of the quasiperpendicular terrestrial bow shock. A timing analysis gives shock speeds and normals; the shock speed is used to convert the temporal measurement to a spatial one. A hyperbolic tangent function is fitted to each density transition, which captures the main shock transition, but not overshoot or undershoot nor foot features. We find that, at a low Mach number M, the density transition is consistent with both ion inertial scales c/omega(pi) and convected gyroradii v(sh,n)/Omega(ci,2), while at M>/=4-5 only the convected gyroradius is the preferred scale for the shock density transition and takes the value L approximately 0.4v(sh,n)/Omega(ci,2).

Reactivity effects of moderator voids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahlfeld, C.E.; Pryor, R.J.

1975-01-01

Reactivity worths for large moderator voids similar to those produced by steaming in postulated reactor transients were measured in the Process Development Pile (PDP) reactor. The experimental results were compared to the computed void worths obtained from techniques currently used in routine safety analyses. Neutron energy spectrum measurements were used to verify a modified lattice pattern that correctly computed the measured spectrum, and consequently, improved macroscopic cross sections. In addition, a special two-dimensional transport calculation was performed to obtain an axially defined diffusion coefficient for the void region. The combination of the modified lattice calculations and the axial diffusion coefficientmore » yielded void reactivity worths which agreed very well with experiment. It was concluded that the computational modules available in the JOSHUA system (GLASS, GRIMHX) would yield accurate void reactivity worths in SLR--SRP safety analysis studies, provided the above mentioned modifications were made.« less

Diffusion phenomena of cells and biomolecules in microfluidic devices

PubMed Central

Yildiz-Ozturk, Ece; Yesil-Celiktas, Ozlem

2015-01-01

Biomicrofluidics is an emerging field at the cross roads of microfluidics and life sciences which requires intensive research efforts in terms of introducing appropriate designs, production techniques, and analysis. The ultimate goal is to deliver innovative and cost-effective microfluidic devices to biotech, biomedical, and pharmaceutical industries. Therefore, creating an in-depth understanding of the transport phenomena of cells and biomolecules becomes vital and concurrently poses significant challenges. The present article outlines the recent advancements in diffusion phenomena of cells and biomolecules by highlighting transport principles from an engineering perspective, cell responses in microfluidic devices with emphases on diffusion- and flow-based microfluidic gradient platforms, macroscopic and microscopic approaches for investigating the diffusion phenomena of biomolecules, microfluidic platforms for the delivery of these molecules, as well as the state of the art in biological applications of mammalian cell responses and diffusion of biomolecules. PMID:26180576

Electrostatically Directed Self-Assembly of Ultrathin Supramolecular Polymer Microcapsules

PubMed Central

Parker, Richard M; Zhang, Jing; Zheng, Yu; Coulston, Roger J; Smith, Clive A; Salmon, Andrew R; Yu, Ziyi; Scherman, Oren A; Abell, Chris

2015-01-01

Supramolecular self-assembly offers routes to challenging architectures on the molecular and macroscopic scale. Coupled with microfluidics it has been used to make microcapsules—where a 2D sheet is shaped in 3D, encapsulating the volume within. In this paper, a versatile methodology to direct the accumulation of capsule-forming components to the droplet interface using electrostatic interactions is described. In this approach, charged copolymers are selectively partitioned to the microdroplet interface by a complementary charged surfactant for subsequent supramolecular cross-linking via cucurbit[8]uril. This dynamic assembly process is employed to selectively form both hollow, ultrathin microcapsules and solid microparticles from a single solution. The ability to dictate the distribution of a mixture of charged copolymers within the microdroplet, as demonstrated by the single-step fabrication of distinct core–shell microcapsules, gives access to a new generation of innovative self-assembled constructs. PMID:26213532

Gold and iodine diffusion in large area perovskite solar cells under illumination.

PubMed

Cacovich, S; Ciná, L; Matteocci, F; Divitini, G; Midgley, P A; Di Carlo, A; Ducati, C

2017-04-06

Operational stability is the main issue hindering the commercialisation of perovskite solar cells. Here, a long term light soaking test was performed on large area hybrid halide perovskite solar cells to investigate the morphological and chemical changes associated with the degradation of photovoltaic performance occurring within the devices. Using Scanning Transmission Electron Microscopy (STEM) in conjunction with EDX analysis on device cross sections, we observe the formation of gold clusters in the perovskite active layer as well as in the TiO 2 mesoporous layer, and a severe degradation of the perovskite due to iodine migration into the hole transporter. All these phenomena are associated with a drastic drop of all the photovoltaic parameters. The use of advanced electron microscopy techniques and data processing provides new insights on the degradation pathways, directly correlating the nanoscale structure and chemistry to the macroscopic properties of hybrid perovskite devices.

Microstructure-scaled active sites imaging of a solid oxide fuel cell composite cathode

NASA Astrophysics Data System (ADS)

Nagasawa, Tsuyoshi; Hanamura, Katsunori

2017-11-01

Active sites for oxygen reduction reaction in strontium-doped lanthanum manganite (LSM)/scandia-stabilized zirconia (ScSZ) composite cathode of solid oxide fuel cell (SOFC) is visualized in microstructure scale by oxygen isotope labeling. In order to quench a reaction, a SOFC power generation equipment with a nozzle for direct helium gas impinging jet to the cell is prepared. A typical electrolyte-supported cell is operated by supplying 18O2 at 1073 K and abruptly quenched to room temperature. During the quench, the temperature of the cell is decreased from 1073 K to 673 K in 1 s. The 18O concentration distribution in the cross section of the quenched cathode is obtained by secondary ion mass spectrometry (SIMS) with a spatial resolution of 50 nm. The obtained 18O mapping gives the first visualization of highly distributed active sites in the composite cathode both in macroscopic and particle scales.

Bacterial Inclusion Bodies Contain Amyloid-Like Structure

PubMed Central

Wang, Lei; Maji, Samir K; Sawaya, Michael R; Eisenberg, David; Riek, Roland

2008-01-01

Protein aggregation is a process in which identical proteins self-associate into imperfectly ordered macroscopic entities. Such aggregates are generally classified as amorphous, lacking any long-range order, or highly ordered fibrils. Protein fibrils can be composed of native globular molecules, such as the hemoglobin molecules in sickle-cell fibrils, or can be reorganized β-sheet–rich aggregates, termed amyloid-like fibrils. Amyloid fibrils are associated with several pathological conditions in humans, including Alzheimer disease and diabetes type II. We studied the structure of bacterial inclusion bodies, which have been believed to belong to the amorphous class of aggregates. We demonstrate that all three in vivo-derived inclusion bodies studied are amyloid-like and comprised of amino-acid sequence-specific cross-β structure. These findings suggest that inclusion bodies are structured, that amyloid formation is an omnipresent process both in eukaryotes and prokaryotes, and that amino acid sequences evolve to avoid the amyloid conformation. PMID:18684013

Texture analysis of Napoleonic War Era copper bolts

NASA Astrophysics Data System (ADS)

Malamud, Florencia; Northover, Shirley; James, Jon; Northover, Peter; Kelleher, Joe

2016-04-01

Neutron diffraction techniques are suitable for volume texture analyses due to high penetration of thermal neutrons in most materials. We have implemented a new data analysis methodology that employed the spatial resolution achievable by a time-of-flight neutron strain scanner to non-destructively determine the crystallographic texture at selected locations within a macroscopic sample. The method is based on defining the orientation distribution function of the crystallites from several incomplete pole figures, and it has been implemented on ENGIN-X, a neutron strain scanner at the Isis Facility in the UK. Here, we demonstrate the application of this new texture analysis methodology in determining the crystallographic texture at selected locations within museum quality archaeological objects up to 1 m in length. The results were verified using samples of similar, but less valuable, objects by comparing the results of applying this method with those obtained using both electron backscatter diffraction and X-ray diffraction on their cross sections.

Squeezed cooling of mechanical motion beyond the resolved-sideband limit

NASA Astrophysics Data System (ADS)

Yang, Cheng; Zhang, Lin; Zhang, Weiping

2018-04-01

Cavity optomechanics provides a unique platform for controlling micromechanical systems by means of optical fields that cross the classical-quantum boundary to achieve solid foundations for quantum technologies. Currently, optomechanical resonators have become promising candidates for the development of precisely controlled nano-motors, ultrasensitive sensors and robust quantum information processors. For all these applications, a crucial requirement is to cool the mechanical resonators down to their quantum ground states. In this paper, we present a novel cooling scheme to further cool a micromechanical resonator via the noise squeezing effect. One quadrature in such a resonator can be squeezed to induce enhanced fluctuations in the other, “heated” quadrature, which can then be used to cool the mechanical motion via conventional optomechanical coupling. Our theoretical analysis and numerical calculations demonstrate that this squeeze-and-cool mechanism offers a quick technique for deeply cooling a macroscopic mechanical resonator to an unprecedented temperature region below the zero-point fluctuations.

Cross-Section Parameterizations for Pion and Nucleon Production From Negative Pion-Proton Collisions

NASA Technical Reports Server (NTRS)

Norbury, John W.; Blattnig, Steve R.; Norman, Ryan; Tripathi, R. K.

2002-01-01

Ranft has provided parameterizations of Lorentz invariant differential cross sections for pion and nucleon production in pion-proton collisions that are compared to some recent data. The Ranft parameterizations are then numerically integrated to form spectral and total cross sections. These numerical integrations are further parameterized to provide formula for spectral and total cross sections suitable for use in radiation transport codes. The reactions analyzed are for charged pions in the initial state and both charged and neutral pions in the final state.

Formulation and Analysis of the Quantum Radar Cross Section

NASA Astrophysics Data System (ADS)

Brandsema, Matthew J.

In radar, the amount of returns that an object sends back to the receiver after being struck by an electromagnetic wave is characterized by what is known as the radar cross section, denoted by sigma typically. There are many mechanisms that affect how much radiation is reflected back in the receiver direction, such as reflectivity, physical contours and dimensions, attenuation properties of the materials, projected cross sectional area and so on. All of these characteristics are lumped together in a single value of sigma, which has units of m2. Stealth aircrafts for example are designed to minimize its radar cross section and return the smallest amount of radiation possible in the receiver direction. A new concept has been introduced called quantum radar, that uses correlated quantum states of photons as well as the unique properties of quantum mechanics to ascertain information on a target at a distance. At the time of writing this dissertation, quantum radar is very much in its infancy. There still exist fundamental questions about the feasibility of its implementation, especially in the microwave spectrum. However, what has been theoretically determined, is that quantum radar has a fundamental advantage over classical radar in terms of resolution and returns in certain regimes. Analogous to the classical radar cross section (CRCS), the concept of the quantum radar cross section (QRCS) has been introduced. This quantity measures how an object looks to a quantum radar be describing how a single photon, or small cluster of photons scatter off of a macroscopic target. Preliminary simulations of the basic quantum radar cross section equation have yielded promising results showing an advantage in sidelobe response in comparison to the classical RCS. This document expands upon this idea by providing insight as to where this advantage originates, as well as developing more rigorous simulation analysis, and greatly expanding upon the theory. The expanded theory presented in this document includes re-deriving the QRCS formula to be a general bistatic formula, as the current equation is only valid for monostatic radar geometries. This re-derivation process also leads to the addition of terms that capture the effect of photon polarization, something that is not properly taken into account in the current literature. Most importantly, a new formulation of the QRCS formula will be derived that includes writing the equation in terms of Fourier transforms. This has a profound impact on the analysis of the theory of the QRCS as it allows for the derivation of closed form solutions of certain geometries, something that has never been possible due to the form of the current QRCS equation. All together, this document will provide a complete and general theory of the QRCS. After deriving the necessary equations, there will be extensive work in the utilization of these equations in deriving geometry dependent responses and comparing the closed form solutions to the classical solutions as well as comparing the solutions to the numerical simulations. The current literature relies exclusively on numerical simulations to analyze the behavior of the QRCS. The simulations done do not take into account the macroscopic nature of the target. Because the atoms are so numerous, and because of the underlying Fourier transform relationship, there are many issues of sampling that must be taken into account when performing simulations. Simulating an object with too few samples results in an aliased and incorrect version of the QRCS response. An extensive error analysis is presented which ensures an accurate simulation result based on sample number. Finally, possible future work endeavors will be presented which include QRCS diffraction, shadowing, more accurate simulation concepts, and the effect of quantum tunneling on the QRCS response.

The multistate impact parameter method for molecular charge exchange in nitrogen

NASA Technical Reports Server (NTRS)

Ioup, J. W.

1980-01-01

The multistate impact parameter method is applied to the calculation of total cross sections for low energy change transfer between nitrogen ions and nitrogen molecules. Experimental data showing the relationships between total cross section and ion energy for various pressures and electron ionization energies were obtained. Calculated and experimental cross section values from the work are compared with the experimental and theoretical results of other investigators.

P(P bar)P elastic scattering and cosmic ray data

NASA Technical Reports Server (NTRS)

FAZAL-E-ALEEM; Saleem, M.

1985-01-01

It is shown that the total cross section for pp elastic scattering at cosmic ray energies, as well as the total cross section, the slope parameter b(s,t) and the differential cross section for small momentum transfer at ISR and collider energies for p(p)p elastic scattering can be simultaneously fitted by using a simple Regge pole model. The results of this theory is discussed in detail.