bluuebunny/crossref_metadata_2025 huggingface dataset:
Independent calculation of monitor units for VMAT and SPORT
Authors: Chen Xin , Bush Karl , Ding Aiping , Xing Lei
Published: January 2015

Purpose:

Dose and monitor units (MUs) represent two important facets of a radiation therapy treatment. In current practice, verification of a treatment plan is commonly done in dose domain, in which a phantom measurement or forward dose calculation is performed to examine the dosimetric accuracy and the MU settings of a given treatment plan. While it is desirable to verify directly the MU settings, a computational framework for obtaining the MU values from a known dose distribution has yet to be developed. This work presents a strategy to calculate independently the MUs from a given dose distribution of volumetric modulated arc therapy (VMAT) and station parameter optimized radiation therapy (SPORT).

Methods:

The dose at a point can be expressed as a sum of contributions from all the station points (or control points). This relationship forms the basis of the proposed MU verification technique. To proceed, the authors first obtain the matrix elements which characterize the dosimetric contribution of the involved station points by computing the doses at a series of voxels, typically on the prescription surface of the VMAT/SPORT treatment plan, with unit MU setting for all the station points. An in‐house Monte Carlo (MC) software is used for the dose matrix calculation. The MUs of the station points are then derived by minimizing the least‐squares difference between doses computed by the treatment planning system (TPS) and that of the MC for the selected set of voxels on the prescription surface. The technique is applied to 16 clinical cases with a variety of energies, disease sites, and TPS dose calculation algorithms.

Results:

For all plans except the lung cases with large tissue density inhomogeneity, the independently computed MUs agree with that of TPS to within 2.7% for all the station points. In the dose domain, no significant difference between the MC and Eclipse Anisotropic Analytical Algorithm (AAA) dose distribution is found in terms of isodose contours, dose profiles, gamma index, and dose volume histogram (DVH) for these cases. For the lung cases, the MC‐calculated MUs differ significantly from that of the treatment plan computed using AAA. However, the discrepancies are reduced to within 3% when the TPS dose calculation algorithm is switched to a transport equation‐based technique (Acuros™). Comparison in the dose domain between the MC and Eclipse AAA/Acuros calculation yields conclusion consistent with the MU calculation.

Conclusions:

A computational framework relating the MU and dose domains has been established. The framework does not only enable them to verify the MU values of the involved station points of a VMAT plan directly in the MU domain but also provide a much needed mechanism to adaptively modify the MU values of the station points in accordance to a specific change in the dose domain.
Breast dosimetry in transverse and longitudinal field MRI‐Linac radiotherapy systems
Authors: Mahdavi S. R. , Esmaeeli A. D. , Pouladian M. , Monfared A. S. , Sardari D. , Bagheri S.
Published: January 2015

Purpose:

In the framework of developing the integration of a MRI‐Linac system, configurations of MRI‐Linac units were simulated in order to improve the dose distribution in tangential breast radiotherapy using transverse and longitudinal magnetic field geometries of Lorentz force for both medial and lateral tangential fields.

Methods:

In this work, the geant4 Monte Carlo (MC) code was utilized to compare dose distributions in breast radiotherapy for Linac‐MR systems in the transverse and longitudinal geometries within humanoid phantoms across a range of magnetic field strengths of 0.5 and 1.5 T. The dose increment due to scattering from the coils was investigated for both geometries as well. Computed tomography images of two patients were used for MC simulations. One patient had intact breast while the other was mastectomized. In the simulations, planning and methods of chest wall irradiation were similar to the actual clinical planning.

Results:

In a longitudinal geometry, the magnetic field is shown to restrict the lateral spread of secondary electrons to the lung, heart, and contralateral organs, which reduced the mean dose of the ipsilateral lung and heart by means of 17.2% and 6% at 1.5 T, respectively. The transverse configuration exhibits a significant increase in tissue interface effects, which increased dose buildup in the entrance regions of the lateral and medial tangent beams to the planning target volume (PTV) and improved dose homogeneity within the PTV. The improved relative average homogeneity index for two patients to the PTV at magnetic field strength of 1.5 T with respect to no magnetic field case evaluated was 11.79% and 34.45% in the LRBP and TRBP geometries, respectively. In both geometries, the simulations show significant mean dose reductions in the contralateral breast and chest wall skin, respectively, by a mean of 16.6% and 24.9% at 0.5 T and 17.2% and 28.1% at 1.5 T in the transverse geometry, and 10.56% and 14.6% at 0.5 T and 11.3% and 16.3% at 1.5 T in the longitudinal geometry. Considering the scattered photons which reflected from the coils, the average relative dose of each voxel is slightly increased by 0.53% and 0.32% in the LRBP and TRBP geometries, respectively.

Conclusions:

Orienting the B0 magnetic field parallel to the photon beam axis, LRBP geometry, tends to restrict the radial spread of secondary electrons which resulted in dose reduction to the lung. Dosimetry issues observed in both Linac‐MR geometries, such as changes to the lateral dose distribution, significantly exhibited dose reduction in the contralateral organs on a representative breast plan. Further, the results show sharper edge dose volume histogram curves at 1.5 T for both geometries, especially in the LRBP configuration.
Feasibility of RACT for 3D dose measurement and range verification in a water phantom
Authors: Alsanea Fahed , Moskvin Vadim , Stantz Keith M.
Published: January 2015

Purpose:

The objective of this study is to establish the feasibility of using radiation‐induced acoustics to measure the range and Bragg peak dose from a pulsed proton beam. Simulation studies implementing a prototype scanner design based on computed tomographic methods were performed to investigate the sensitivity to proton range and integral dose.

Methods:

Derived from thermodynamic wave equation, the pressure signals generated from the dose deposited from a pulsed proton beam with a 1 cm lateral beam width and a range of 16, 20, and 27 cm in water using Monte Carlo methods were simulated. The resulting dosimetric images were reconstructed implementing a 3D filtered backprojection algorithm and the pressure signals acquired from a 71‐transducer array with a cylindrical geometry (30 × 40 cm) rotated over 2π about its central axis. Dependencies on the detector bandwidth and proton beam pulse width were performed, after which, different noise levels were added to the detector signals (using 1 μs pulse width and a 0.5 MHz cutoff frequency/hydrophone) to investigate the statistical and systematic errors in the proton range (at 20 cm) and Bragg peak dose (of 1 cGy).

Results:

The reconstructed radioacoustic computed tomographic image intensity was shown to be linearly correlated to the dose within the Bragg peak. And, based on noise dependent studies, a detector sensitivity of 38 mPa was necessary to determine the proton range to within 1.0 mm (full‐width at half‐maximum) (systematic error < 150 μm) for a 1 cGy Bragg peak dose, where the integral dose within the Bragg peak was measured to within 2%. For existing hydrophone detector sensitivities, a Bragg peak dose of 1.6 cGy is possible.

Conclusions:

This study demonstrates that computed tomographic scanner based on ionizing radiation‐induced acoustics can be used to verify dose distribution and proton range with centi‐Gray sensitivity. Realizing this technology into the clinic has the potential to significantly impact beam commissioning, treatment verification during particle beam therapy and image guided techniques.
Field experimental cells to assess hydrogeological behaviour of store-and-release covers made with phosphate mine waste
Authors: Bossé Bruno , Bussière Bruno , Hakkou Rachid , Maqsoud Abdelkabir , Benzaazoua Mostafa
Published: January 2015

A field investigation was conducted to evaluate the effectiveness of store-and-release (SR) covers made with different phosphate mine wastes in reducing water infiltration (system inclination and surface runoff were neglected) and controlling acid rock drainage (ARD) generation. Four instrumented experimental cells were constructed with different SR layer configurations (two thicknesses and three materials) placed over a capillary break layer. To assess the hydrogeological behaviour of these cover systems, volumetric water content, matric suction, and meteorological monitoring time trends were studied for a period of 1.5 years under actual and extreme conditions typical of an arid climate. Under natural climatic conditions, all net infiltration was released to the atmosphere by the physical process of evaporation (regardless of SR layer thickness and type). Although high surface matric suction (>3000 kPa) decreased the evaporation rate (or release capacity) during the drying period, field tests showed that the studied scenarios limited deep water infiltration even under extreme rainfall events. The release capacity of the SR layer was slightly lower for cover systems made with the finer-grained mine waste (phosphate limestone tailings). This study showed that, for a one-dimensional (1D) condition, the tested phosphate mine wastes have the appropriate hydrogeological properties to be used as components of SR covers under conditions at the Kettara mine site, located near Marrakech, Morocco.
Finding a single-molecule receptor for citramalic acid through supramolecular chelation
Authors: Aakeröy Christer B. , Smith Michelle , Desper John
Published: January 2015

We have demonstrated that the tritopic hydrogen-bond acceptor 1,3,5-(5,6-dimethylbenzimidazol-1-yl)-2,4,6-trimethylbenzene can act as a perfectly complementary receptor for citramalic acid. The solid-state structure of the cocrystal of the two components show that they form 1:1 pairs where each pair is held together by three near-linear O–H···N hydrogen bonds in a converging manner. The conformational flexibility of both species is apparently no hindrance to the formation of discrete dimeric “cups” wherein each species presents three hydrogen-bond donors/acceptors in a face-to-face orientation.
Electron impact excitation and polarization studies of Fe-like W48+ to Al-like W61+ ions
Authors: Dipti  , Das Tapasi , Sharma Lalita , Srivastava Rajesh
Published: January 2015

A fully relativistic distorted wave theory has been employed to study electron impact excitations of specific magnetic sublevels in Fe-like W48+ through Al-like W61+ ions. M-shell excitations, namely, 3p → 3d by electron impact have been considered in these 14 tungsten ions. Excitation cross sections are reported for incident electron energies from the threshold to 20 keV. In addition, for each transition, analytic fitting to the cross sections are provided. The degree of polarization of the emitted photons from the decay of the different excited anisotropic states of the tungsten ions is also calculated through the expressions we derived using density matrix theory in terms of magnetic sublevel excitation cross sections.
Automatic Simplified Symbolic Analysis of Analog Circuits Using Modified Nodal Analysis and Genetic Algorithm
Authors: Shokouhifar Mohammad , Jalali Ali
Published: January 2015

In this paper, a hybrid methodology based on modified nodal analysis (MNA) and genetic algorithm (GA) is presented for simplified symbolic small-signal analysis of analog circuits containing semiconductor devices like MOSFETs. At first, the circuit is analyzed by the MNA, and the derived exact continuous-time transfer function is automatically simplified via GA. We propose a new multi-objective criterion for symbolic simplification of continuous-time transfer functions, which can be performed by such optimization algorithms as local-search algorithms, heuristic algorithms, swarm-intelligence algorithms, etc. In this paper, GA is used to validate the proposed simplification criterion. All processes including netlist text pre-processing, symbolic analysis via MNA, post-processing, and simplification via GA are consecutively run in an m-file MATLAB program. The comparison of obtained numeric results with HSPICE demonstrates the efficiency of the proposed methodology.
QUARTZ CRYSTAL MICROBALANCE STUDY OF KINETICS AND THERMODYNAMICS OF IgG ADSORPTION ON THE POLYSTYRENE SURFACE
Authors: FENG BO , FENG XI , XIE XIAOMEI , WANG CAIYUN , ZHANG MENGXUE , ZHANG XIAOYUN
Published: January 2015

Polystyrene (PS) is a common substrate material for protein adsorption on biosensors and bioassays. By employing a quartz crystal microbalance (QCM) technique, we studied the kinetics and thermodynamics of anti-HBeAg adsorption on this substrate in situ. First, a thin PS film was deposited on the interface between the liquid and the quartz crystal wafer. Second, a solution containing anti-HBeAg was introduced into the holding tank. Third, we measured the change in the oscillation frequency of the quartz that was induced by the antibody–PS binding, which in turn depended on macroscopic parameters, such as antibody concentration and solution temperature, as well as on microscopic parameters, such as the diffusion type and the change in Gibb's free energy. The adsorption rate and capacity of anti-HBeAg on the PS surface were quantified and fitted using the conventional Langmuir model. It was shown that this model was applicable to protein–PS interface system. Approximately 250 nm2of the surface area was occupied by a single antibody molecule at 298 K when the concentration was 90 μg/mL. The adsorption process might have been controlled by both liquid film and particle diffusions.
Spatial routing with light-induced waveguides in uniaxial nematic liquid crystals
Authors: Sala Filip A. , Karpierz Mirosław A. , Assanto Gaetano
Published: January 2015

In reorientational soft-matter with uniaxial character, such as nematic liquid crystals (NLCs), self-confined beams into spatial optical solitons are graded-index waveguides subject to birefringent walkoff. We investigate a router to be realized in a planar cell with an inhomogeneous distribution of the optic axis. Based on the input beam position, the proposed demultiplexer can direct the soliton and the copolarized guided-wave signal(s) to various output ports, enhancing the transverse separation of the exit channels and therefore minimizing crosstalk. Both the soliton and the signal(s) maintain their phasefronts normal to launch and exit wavevectors, allowing for excellent coupling into output channels/fibers at the device exit.
Fabrication of gold micro/nanostructures by femtosecond laser direct writing and chemical etching
Authors: Zhang Hongxin , Jia Tianqing , Zhou Kan , Liu Jukun , Feng Donghai , Zhang Shian , Sun Zhenrong
Published: January 2015

In this paper, we report gold micro/nanostructures fabricated by a method called lithographically patterned nanostructure by chemical etching (LPNCE). In the LPNCE method, the photoresist layer, composed of pentaerythritol triacrylate (PETA, monomer) and isopropyl thioxanthone (ITX, photoinitiator), is dropped on gold film, and subsequently polymerized via two-photon absorption of 800 nm femtosecond laser. Micro/nanostructures are fabricated by the direct laser writing. The unpolymerized photoresist is washed by isopropanol, and the exposed gold is dissolved by KI 3 aqueous solution. Finally, polymers are removed by NaOH ethanol solution. Arbitrary 2D gold micro/nanostructures can be fabricated quickly by the direct laser writing and chemical etching method. The good electro-conductibility of these micro/nanostructures guarantees wide applications in micro-electronic devices, plasmonics and biosensors, etc.
MULTICENTRIC RETROPERITONEAL LEIOMYOSARCOMA WITH SATELLITE LESIONS NOT FOUND ON PET-CT: A CASE REPORT AND LITERATURE REVIEW
Authors: Hsieh Chin-Chiang , Yang Rong-Sen , Lin Yih-Jyh , Huang Kuo-Yuan
Published: January 2015

Most retroperitoneal leiomyosarcomas are clinically silent and are usually detected late, so a large size main tumor accompanied by satellite lesions might be presented. We report a case of a large multicentric retroperitoneal leiomyosarcoma with satellite lesions in the left iliac region, mimicking an abscess, was found on pre-operative pelvic computed tomography (CT). Positron emission tomography (PET-CT) was performed, but revealed only focal bony destruction of the left ilium and no discernable lesions in the abdomen. After resection of the iliacus satellite lesion, CT and magnetic resonance imaging (MRI) of the abdomen revealed another huge retroperitoneal leiomyosarcoma with invasion of the left kidney and ureter, descending colon and left iliac arteries. The patient was then treated with a multidisciplinary extensive excision operation. The clinical presentation, operative findings and imaging findings were reported and related articles were reviewed.
RESOURCE REDISTRIBUTION METHOD FOR SHORT-TERM RECOVERY OF SOCIETY AFTER LARGE-SCALE DISASTERS
Authors: LUBASHEVSKIY VASILY , KANNO TARO , FURUTA KAZUO
Published: January 2015

Recovery of society after a large-scale disaster generally consists of two phases, short- and long-term recoveries. The main goal of the short-term recovery is to bounce the damaged system back to the operating standards enabling residents in damaged cities to survive, and fast supply with vital resources to them is one of its important elements. We propose a general principle by which the required redistribution of vital resources between the affected and neighboring cities can be efficiently implemented. The short-term recovery is a rescuer operation where uncertainty in evaluating the state of damaged region is highly probable. To allow for such an operation, the developed principle involves two basic components. The first one of ethic nature is the triage concept determining the current city priority in the resource delivery. The second one is the minimization of the delivery time subjected to this priority. Finally a certain plan of the resource redistribution is generated according to this principle. Several specific examples are studied numerically. It elucidates, in particular, the effects of system characteristics such as the city limit capacity in resource delivery, the type of initial resource allocation among the cities, the number of cities able to participate in the resource redistribution, and the damage level in the affected cities. As far as the uncertainty in evaluating the state of damaged region is concerned, some specific cases were studied. It assumes the initial communication system has crashed and formation of a new one and the resource redistribution proceed synchronously. The obtained results enable us to consider the resource redistribution plan governed by the proposed method semi-optimal and rather efficient especially under uncertainty.
Utilization of Anodized Aluminum Oxide Substrate for the Growth of ZnO Microcrystals on Polygonized Spirals
Authors: Deulkar Sundeep H. , Bhosale C. H. , Huang Jow-Lay
Published: January 2015

Anodized Aluminum Oxide (AAO) has been utilized as a substrate for the screw dislocation assisted growth of polygonize spirals (PS) of ZnO with diameter of the order of ~230 μm by Chemical Vapour Deposition (CVD) process. Stoichiometric ZnO microcrystals nucleated on the terraces and tops of these polygonized spirals.

Stress inherent in the ZnO polygonized spiral morphology (~ 3.57 GPa) was deciphered from the values of the magnitude of shift in observed 2θ values of Glancing Incidence angle XRD (GIXRD) peaks from the standard values (JCPDS 36-1451) for hexagonal Zincite. The growth mechanism of these PS was explained albeit to a limited extent on the basis of the Burton, Cabrera and Frank (BCF) theory and its later modification, wherein data obtained from exsitu SEM measurements concomitant with numerical analysis was utilized to decipher values of the critical radius and supersaturation ratios. Nucleation of ZnO microcrystals on the PS was explained on the basis of the supersaturation ratio and the plausible values of diffusion lengths, existent on the summits of these PS. Retardation of the step rotation of the PS, due to elastic stress around the dislocation source and the Gibbs–Thomson effect, was explained on the basis of numerical coefficient ω0, the dimensionless frequency of spiral rotation. Role of stress in inhibition of ZnO nucleation on PS of smaller heights and with larger supersaturation ratio, has been discussed albeit qualitatively.

The optical characteristics of a single ZnO microcrystal has been analyzed by room temperature CL measurements in the wavelength range 350 nm to 650 nm, revealing a single high intensity peak at 382 nm corresponding to a excitonic bandgap of 3.25 eV.
On the relativistic micro-canonical ensemble and relativistic kinetic theory for N relativistic particles in inertial and non-inertial rest frames
Authors: Alba David , Crater Horace W. , Lusanna Luca
Published: January 2015

A new formulation of relativistic classical mechanics allows a reconsideration of old unsolved problems in relativistic kinetic theory and in relativistic statistical mechanics. In particular a definition of the relativistic micro-canonical partition function is given strictly in terms of the Poincaré generators of an interacting N-particle system both in the inertial and non-inertial rest frames. The non-relativistic limit allows a definition of both the inertial and non-inertial micro-canonical ensemble in terms of the Galilei generators.
Wave function of the universe from a matrix-valued first-order formalism
Authors: Kruglov Sergey I. , Faizal Mir
Published: January 2015

In this paper, the Wheeler–DeWitt equation in full superspace formalism will be written in a matrix-valued first-order formalism. We will also analyze the Wheeler–DeWitt equation in minisuperspace approximation using this matrix-valued first-order formalism. We will note that this Wheeler–DeWitt equation, in this minisuperspace approximation, can be expressed as an eigenvalue equation. We will use this fact to analyze the spacetime foam in this formalism. This will be done by constructing a statistical mechanical partition function for the Wheeler–DeWitt equation in this matrix-valued first-order formalism. This will lead to a possible solution for the cosmological constant problem.
Asymptotically isometric metrics on relatively hyperbolic groups and marked length spectrum
Authors: Fujiwara Koji
Published: January 2015

We prove asymptotically isometric, coarsely geodesic metrics on a toral relatively hyperbolic group are coarsely equal. The theorem applies to all lattices in SO (n, 1). This partly verifies a conjecture by Margulis. In the case of hyperbolic groups/spaces, our result generalizes a theorem by Furman and a theorem by Krat.

We discuss an application to the isospectral problem for the length spectrum of Riemannian manifolds. The positive answer to this problem has been known for several cases. Most of them have hyperbolic fundamental groups. We do not solve the isospectral problem in the original sense, but prove the universal covers are (1, C)-quasi-isometric if the fundamental group is a toral relatively hyperbolic group.
Exergy Analysis of Various Absorption Heat Transformer Systems Using Classical and Modified Gouy–Stodola Equation
Authors: Goel T. , Sachdeva G.
Published: January 2015

In the present study, performance evaluation of three different configurations of absorption heat transformer (AHT) is carried out by supplying the waste heat of same mass and same temperature; and exergy analysis is done using both the classical and modified Gouy–Stodola equation. For this a mathematical model is developed for all the three arrangements in Engineering Equation Solver. Water–lithium bromide is used as a working pair. The results of exergy destruction with classical and modified Gouy–Stodola equation are compared for different systems. Further various operating parameters are varied to predict the performance of the systems on the basis of second law analysis. The result showed that the amount of hot fluid produced in absorber is more for system 3 as compared to other configurations. The irreversibility calculated by the modified approach comes out to be 25.78%, 23.60%, and 23.45% more than the exergy destruction obtained by the classical approach in the three cases, respectively. Thus, there is a need to employ the modified approach of Gouy–Stodola equation for calculating the real irreversibility which helps in predicting the scope of improvement and the performance of the system more accurately.
The Evolution of Plant Secretory Structures and Emergence of Terpenoid Chemical Diversity
Authors: Lange Bernd Markus
Published: January 2015

Secretory structures in terrestrial plants appear to have first emerged as intracellular oil bodies in liverworts. In vascular plants, internal secretory structures, such as resin ducts and laticifers, are usually found in conjunction with vascular bundles, whereas subepidermal secretory cavities and epidermal glandular trichomes generally have more complex tissue distribution patterns. The primary function of plant secretory structures is related to defense responses, both constitutive and induced, against herbivores and pathogens. The ability to sequester secondary (or specialized) metabolites and defense proteins in secretory structures was a critical adaptation that shaped plant-herbivore and plant-pathogen interactions. Although this review places particular emphasis on describing the evolution of pathways leading to terpenoids, it also assesses the emergence of other metabolite classes to outline the metabolic capabilities of different plant lineages.
Moving Toward a Comprehensive Map of Central Plant Metabolism
Authors: Sulpice Ronan , McKeown Peter C.
Published: January 2015

Decades of intensive study have led to the discovery of the main pathways involved in central metabolism but only some of the pathways and regulatory networks in which they are embedded. In this review, we discuss techniques used to assemble these pathways into a systems biology framework that can enable accurate modeling of the response of central metabolism to changes, including ways to perturb metabolic systems and assemble the resulting data into a meaningful network. Critically, these networks are of such size and complexity that it is possible to derive them only if data from different groups can be comprehensively and meaningfully combined. We conclude that it is essential to establish common standards for the description of experimental conditions and data collection and to store this information in databases to which the whole community can contribute.
Strigolactones, a Novel Carotenoid-Derived Plant Hormone
Authors: Al-Babili Salim , Bouwmeester Harro J.
Published: January 2015

Strigolactones (SLs) are carotenoid-derived plant hormones and signaling molecules. When released into the soil, SLs indicate the presence of a host to symbiotic fungi and root parasitic plants. In planta, they regulate several developmental processes that adapt plant architecture to nutrient availability. Highly branched/tillered mutants in Arabidopsis, pea, and rice have enabled the identification of four SL biosynthetic enzymes: a cis/trans-carotene isomerase, two carotenoid cleavage dioxygenases, and a cytochrome P450 (MAX1). In vitro and in vivo enzyme assays and analysis of mutants have shown that the pathway involves a combination of new reactions leading to carlactone, which is converted by a rice MAX1 homolog into an SL parent molecule with a tricyclic lactone moiety. In this review, we focus on SL biosynthesis, describe the hormonal and environmental factors that determine this process, and discuss SL transport and downstream signaling as well as the role of SLs in regulating plant development.
The Mechanism and Key Molecules Involved in Pollen Tube Guidance
Authors: Higashiyama Tetsuya , Takeuchi Hidenori
Published: January 2015

During sexual reproduction of flowering plants, pollen tube guidance by pistil tissue is critical for the delivery of nonmotile sperm cells to female gametes. Multistep controls of pollen tube guidance can be divided into two phases: preovular guidance and ovular guidance. During preovular guidance, various female molecules, including stimulants for pollen germination and pollen tube growth, are provided to support tube growth toward the ovary, where the ovules are located. After entering the ovary, pollen tubes receive directional cues from their respective target ovules, including attractant peptides for precise, species-preferential attraction. Successful pollen tube guidance in the pistil requires not only nutritional and directional controls but also competency controls to make pollen tubes responsive to guidance cues, regulation to terminate growth once a pollen tube arrives at the target, and strategies to stop ovular attraction depending on the fertilization of female gametes.
Universal Dynamics and Renormalization in Many-Body-Localized Systems
Authors: Altman Ehud , Vosk Ronen
Published: January 2015

We survey the recent progress made in understanding nonequilibrium dynamics in closed random systems. The emphasis is on the important role played by concepts from quantum information theory and on the application of systematic renormalization group methods to capture universal aspects of the dynamics. Finally, we outline some outstanding open questions, which include the description of the many-body-localization phase transition and the identification of physical systems that allow systematic experimental study of these phenomena.
Innate Immune Recognition of Cancer
Authors: Woo Seng-Ryong , Corrales Leticia , Gajewski Thomas F.
Published: January 2015

The observation that a subset of cancer patients show evidence for spontaneous CD8+ T cell priming against tumor-associated antigens has generated renewed interest in the innate immune pathways that might serve as a bridge to an adaptive immune response to tumors. Manipulation of this endogenous T cell response with therapeutic intent—for example, using blocking antibodies inhibiting PD-1/PD-L1 (programmed death-1/programmed death ligand 1) interactions—is showing impressive clinical results. As such, understanding the innate immune mechanisms that enable this T cell response has important clinical relevance. Defined innate immune interactions in the cancer context include recognition by innate cell populations (NK cells, NKT cells, and γδ T cells) and also by dendritic cells and macrophages in response to damage-associated molecular patterns (DAMPs). Recent evidence has indicated that the major DAMP driving host antitumor immune responses is tumor-derived DNA, sensed by the stimulator of interferon gene (STING) pathway and driving type I IFN production. A deeper knowledge of the clinically relevant innate immune pathways involved in the recognition of tumors is leading toward new therapeutic strategies for cancer treatment.
ESM 2.0: State of the Art and Future Potential of Experience Sampling Methods in Organizational Research
Authors: Beal Daniel J.
Published: January 2015

The use of experience sampling methods (ESM) and related techniques has exploded in organizational research. The goals of this review are to provide a focused perspective on the state of the art in using ESM and set the stage for what ESM will look like in the years to come. First, I provide a conceptually based discussion of exactly what is and what is not ESM. Next, I discuss the more advantageous elements of ESM that have surfaced from the range of disciplines that enjoy its use (e.g., reduced memory and methods biases), followed by the inevitable challenges that have sometimes limited its utility (e.g., issues with repeated assessment, missing data, and internal validity). Finally, I discuss three innovations of ESM (e.g., trait assessment, expansion to higher levels of analysis, and connection to big data) that seem likely to ensure its continued and expanded influence as a common tool for examining not only within-person psychological processes at work, but higher levels of analysis as well.
The Emerging Picture of Autism Spectrum Disorder: Genetics and Pathology
Authors: Chen Jason A. , Peñagarikano Olga , Belgard T. Grant , Swarup Vivek , Geschwind Daniel H.
Published: January 2015

Autism spectrum disorder (ASD) is defined by impaired social interaction and communication accompanied by stereotyped behaviors and restricted interests. Although ASD is common, its genetic and clinical features are highly heterogeneous. A number of recent breakthroughs have dramatically advanced our understanding of ASD from the standpoint of human genetics and neuropathology. These studies highlight the period of fetal development and the processes of chromatin structure, synaptic function, and neuron-glial signaling. The initial efforts to systematically integrate findings of multiple levels of genomic data and studies of mouse models have yielded new clues regarding ASD pathophysiology. This early work points to an emerging convergence of disease mechanisms in this complex and etiologically heterogeneous disorder.
Engineered In Vitro Disease Models
Authors: Benam Kambez H. , Dauth Stephanie , Hassell Bryan , Herland Anna , Jain Abhishek , Jang Kyung-Jin , Karalis Katia , Kim Hyun Jung , MacQueen Luke , Mahmoodian Roza , Musah Samira , Torisawa Yu-suke , van der Meer Andries D. , Villenave Remi , Yadid Moran , Parker Kevin K. , Ingber Donald E.
Published: January 2015

The ultimate goal of most biomedical research is to gain greater insight into mechanisms of human disease or to develop new and improved therapies or diagnostics. Although great advances have been made in terms of developing disease models in animals, such as transgenic mice, many of these models fail to faithfully recapitulate the human condition. In addition, it is difficult to identify critical cellular and molecular contributors to disease or to vary them independently in whole-animal models. This challenge has attracted the interest of engineers, who have begun to collaborate with biologists to leverage recent advances in tissue engineering and microfabrication to develop novel in vitro models of disease. As these models are synthetic systems, specific molecular factors and individual cell types, including parenchymal cells, vascular cells, and immune cells, can be varied independently while simultaneously measuring system-level responses in real time. In this article, we provide some examples of these efforts, including engineered models of diseases of the heart, lung, intestine, liver, kidney, cartilage, skin and vascular, endocrine, musculoskeletal, and nervous systems, as well as models of infectious diseases and cancer. We also describe how engineered in vitro models can be combined with human inducible pluripotent stem cells to enable new insights into a broad variety of disease mechanisms, as well as provide a test bed for screening new therapies.
DNA Replication Stress as a Hallmark of Cancer
Authors: Macheret Morgane , Halazonetis Thanos D.
Published: January 2015

Human cancers share properties referred to as hallmarks, among which sustained proliferation, escape from apoptosis, and genomic instability are the most pervasive. The sustained proliferation hallmark can be explained by mutations in oncogenes and tumor suppressors that regulate cell growth, whereas the escape from apoptosis hallmark can be explained by mutations in the TP53, ATM, or MDM2 genes. A model to explain the presence of the three hallmarks listed above, as well as the patterns of genomic instability observed in human cancers, proposes that the genes driving cell proliferation induce DNA replication stress, which, in turn, generates genomic instability and selects for escape from apoptosis. Here, we review the data that support this model, as well as the mechanisms by which oncogenes induce replication stress. Further, we argue that DNA replication stress should be considered as a hallmark of cancer because it likely drives cancer development and is very prevalent.
Spintronics and Chirality: Spin Selectivity in Electron Transport Through Chiral Molecules
Authors: Naaman Ron , Waldeck David H.
Published: January 2015

Recent experiments have demonstrated that the electron transmission yield through chiral molecules depends on the electron spin orientation. This phenomenon has been termed the chiral-induced spin selectivity (CISS) effect, and it provides a challenge to theory and promise for organic molecule–based spintronic devices. This article reviews recent developments in our understanding of CISS. Different theoretical models have been used to describe the effect; however, they all presume an unusually large spin-orbit coupling in chiral molecules for the effect to display the magnitudes seen in experiments. A simplified model for an electron's transport through a chiral potential suggests that these large couplings can be manifested. Techniques for measuring spin-selective electron transport through molecules are overviewed, and some examples of recent experiments are described. Finally, we present results obtained by studying several systems, and we describe the possible application of the CISS effect for memory devices.
Realism About Political Corruption
Authors: Philp Mark , Dávid-Barrett Elizabeth
Published: January 2015

This article explores how realism in political theory can inform our understanding of political corruption. Whereas political moralists see corruption as a problem of implementation, which does not undermine their values, realists see corruption as posing a more fundamental problem, challenging the very nature of politics and undermining the attempt to establish and exercise authority in the ordering of conflict and the allocation of resources. Recent realist work has sought to characterize a discrete type of “institutional” corruption, and to construct political corruption as the antithesis of good governance or impartiality. Other work has focused on the micro level, drawing on new insights from psychology and experimental economics to analyze individual decisions and motivations to behave corruptly. This article challenges scholars to build future research upon a richer understanding of the realities of political life that are intrinsic to both individual and institutional patterns of corruption.
Dragging Human Mesenchymal Stem Cells with the Aid of Supramolecular Assemblies of Single-Walled Carbon Nanotubes, Molecular Magnets, and Peptides in a Magnetic Field
Authors: de Paula Ana Cláudia C. , Sáfar Gustavo A. M. , Góes Alfredo M. , Bemquerer Marcelo P. , Ribeiro Marcos A. , Stumpf Humberto O.
Published: January 2015

Human adipose-derived stem cells (hASCs) are an attractive cell source for therapeutic applicability in diverse fields for the repair and regeneration of damaged or malfunctioning tissues and organs. There is a growing number of cell therapies using stem cells due to their characteristics of modulation of immune system and reduction of acute rejection. So a challenge in stem cells therapy is the delivery of cells to the organ of interest, a specific site. The aim of this paper was to investigate the effects of a supramolecular assembly composed of single-walled carbon nanotubes (SWCNT), molecular magnets (lawsone-Co-phenanthroline), and a synthetic peptide (FWYANHYWFHNAFWYANHYWFHNA) in the hASCs cultures. The hASCs were isolated, characterized, expanded, and cultured with the SWCNT supramolecular assembly (SWCNT-MA). The assembly developed did not impair the cell characteristics, viability, or proliferation. During growth, the cells were strongly attached to the assembly and they could be dragged by an applied magnetic field of less than 0.3 T. These assemblies were narrower than their related allotropic forms, that is, multiwalled carbon nanotubes, and they could therefore be used to guide cells through thin blood capillaries within the human body. This strategy seems to be useful as noninvasive and nontoxic stem cells delivery/guidance and tracking during cell therapy.
Nonselective Mevalonate Kinase Inhibitor as a Novel Class of Antibacterial Agents
Authors: Gharehbeglou Mohammad , Arjmand Ghasem , Haeri Mohammad Reza , Khazeni Mohammad
Published: January 2015

Introduction. There are a few evidences about targeting isoprenoids biosynthesis pathway in bacteria for finding new antibiotics. This study was conducted to assess antibacterial effects of vanadyl sulfate (VS), one of the mevalonate kinase inhibitors to find a new target for killing bacteria. Materials and Methods. Antibacterial effect of VS alone and in combination with glycine or EDTA was assessed on Escherichia coli and Pseudomonas aeruginosa as Gram-negative and Staphylococcus aureus and Enterococcus faecalis as Gram-positive bacteria using serial dilution method and minimum inhibitory concentrations (MICs) identified. Result. MICs for S. aureus and E. coli were 4 and 8 mg/mL, respectively. VS could not affect the growth of two other bacteria. However, VS in combination with glycine not only inhibited the growth of E. faecalis and P. aeruginosa, but also reduced MICs for VS-sensitive bacteria (S. aureus and E. coli). EDTA could reduce MIC for E. coli and P. aeruginosa. Conclusion. VS could inhibit the growth of S. aurous and E. coli, and adding glycine or EDTA improved VS antibacterial activity presumably via instability of the cell wall and enhanced transport of VS through bacterial cell wall. Inhibition of the isoprenoid pathway might provide new tools to overcome bacterial resistance.
Windowed Fourier Frames to Approximate Two-Point Boundary Value Problems
Authors: Aljouiee Abdullah , Bhowmik Samir Kumar
Published: January 2015

Boundary value problems arise while modeling various physical and engineering reality. In this communication we investigate windowed Fourier frames focusing two-point BVPs. We approximate BVPs using windowed Fourier frames. We present some numerical results to demonstrate the efficiency of such frame functions to approximate BVPs.
Enhanced Degradation of Lactide-co-Glycolide Polymer with Basic Nucleophilic Drugs
Authors: D’Souza Susan , Faraj Jabar A. , Dorati Rossella , DeLuca Patrick P.
Published: January 2015

The purpose of this study was to examine the degradative effect of weakly basic nucleophilic drugs on a lactide-co-glycolide (PLGA) polymer in a microsphere formulation. Biodegradable PLGA microspheres of two second-generation atypical antipsychotics, Risperidone and Olanzapine, were manufactured using a solvent extraction/evaporation technique. The effect of drug content, buffer pH and temperature on polymer molecular weight and degradation, were examined via a series of experiments and compared against a control (Placebo PLGA microspheres). In comparison to Placebo microspheres, significant polymer molecular weight reduction was observed upon encapsulation of varying levels of either Risperidone or Olanzapine. There was excellent correlation between the extent of molecular weight reduction during manufacture and the amount of encapsulated drug in the microspheres. Subsequent studies on polymer degradation showed: the following (a) the Placebo and Olanzapine microspheres followed pseudo first order kinetics, (b) Risperidone microspheres exhibited biphasic degradation profiles, and (c) polymer degradation was dependent on temperature, not pH. The findings of these studies show that encapsulation of weakly basic nucleophile type drugs into PLGA can accelerate the biodegradation of the PLGA and have major implications on the design of polymeric microsphere drug delivery systems.
Research and Evaluation for Passive Safety System in Low Pressure Reactor
Authors: Chuanxin Peng , Wenbin Zhuo , Bingde Chen , Changhua Nie , Yanping Huang
Published: January 2015

Low pressure reactor is a small size advanced reactor with power of 180 MWt, which is under development at Nuclear Power Institute of China. In order to assess the ability and feasibility of passive safety system, several tests have been implemented on the passive safety system (PSS) test facility. During the LOCA and SBO accident, the adequate core cooling is provided by the performance of passive safety system. In addition the best-estimate thermal hydraulic code, CATHARE V2.1, has been assessed against cold leg LOCA test. The calculation results show that CATHARE is in a satisfactory agreement with the test for the steady state and transient test.
Genetic Association between Methylenetetrahydrofolate Reductase Gene Polymorphism and Risk of Osteonecrosis of the Femoral Head
Authors: Chai Wei , Zhang Zhendong , Ni Ming , Geng Peiliang , Lian Zijian , Zhang Guoqiang , Shi Lewis L. , Chen Jiying
Published: January 2015

Background. Methylenetetrahydrofolate reductase (MTHFR) SNP rs1801133 has been frequently investigated in recent years. Relevant candidate gene association studies with this SNP and osteonecrosis of the femoral head (ONFH) reported conflicting results. Meta-analysis provides a method to combine these data and to determine the association in a larger sample size.Method. We conducted a systematic search to identify possible studies. Four pooled ORs (odds ratios, T versus C, TT versus CC, TT/CT versus CC, and TT versus CT/CC), along with 95% confidence interval (CI), were calculated to evaluate the association between SNP rs1801133 and ONFH susceptibility. Both fixed effects model and random effects model were used.Findings. We eventually included twelve studies in this analysis, with results showing no overall association between ONFH susceptibility and SNP rs1801133 (T versus C:OR=1.15, 95%CI=0.97–1.38; TT versus CC:OR=1.15, 95%CI=0.91–1.46; TT/CT versus CC:OR=1.09, 95%CI=0.95–1.25; and TT versus CT/CC:OR=1.16, 95%CI=0.93–1.45). When stratified based on ethnicity, the results were still not significant.Conclusion. Our findings are generally supportive of no association between MTHFR SNP rs1801133 and the etiology of ONFH.
Upper Gastrointestinal Mucosal Injury and Symptoms in Elderly Low-Dose Aspirin Users
Authors: Shimada Yuji , Nagahara Akihito , Hojo Mariko , Asaoka Daisuke , Sasaki Hitoshi , Ueyama Hiroya , Matsumoto Kenshi , Watanabe Sumio
Published: January 2015

Background. We investigated the prevalence, symptoms, and QOL impact of esophageal (EI), gastric (GI), and duodenal mucosal injury (DI) individually between low-dose aspirin (LDA) users and nonusers to reveal the clinical features of LDA-related mucosal injury.Methods. Data were extracted from the records of subjects who underwent upper gastrointestinal endoscopy at our department between April 2008 and December 2013. Responses from 3162 elderly patients on Frequency Scale for Symptoms of GERD (FSSG) and SF-8 QOL questionnaires (SF-8) were analyzed. FSSG items were classified into total score (TS), reflux score (RS), and dyspepsia score (DS). The SF-8 questionnaire consisted of the physical component summary (PCS) and mental component summary (MCS).Results. Prevalence among LDA users and nonusers, respectively, was 9.6% and 10.0% (P=0.83) for EI, 35.9% and 27.5% (P=0.0027) for GI, 3.3% and 3.4% (P=0.84) for DI, and 8.2% and 5.2% (P=0.036) for mucosal injury in 2 or more organs. LDA users diagnosed with EI had significantly lower PCS, LDA users diagnosed with GI had significantly lower DS, and LDA users diagnosed with DI had significantly lower RS and significantly lower MCS.Conclusion. These results provide important clinical information indicating that symptom-based management is not appropriate in LDA users regarding upper gastrointestinal mucosal injury.