bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrical Impedance Tomography With a Lab‐on‐Chip for Imaging Cells in Culture
Authors: Lemmens Marijn , Biesmans Hanne , Bormans Seppe , Vandenryt Thijs , Thoelen Ronald
Published: April 2018

Electrical Impedance Tomography (EIT) is a non‐invasive, non‐ionizing, and inexpensive imaging modality that is used to image the conductivity distribution inside the subject under test. EIT is an emerging imaging technique that has the potential to be used in a variety of (bio)medical applications. A technology that is easy to integrate into a small portable device and also easy to setup. In this work a custom made impedance analyzer is used as a measurement device. The working principle is based on the different conductivity distributions of the material under test, this due to inhomogeneous bioelectrical properties. However there is one major downside of this technique, the reconstruction problem of EIT is severely ill‐posed. This means that the definition of a correct model is essential. Because of this ill‐posed condition, a comparison of different models is done. In this work, an in depth study is performed to achieve the most optimal way of solving the inverse problem, which leads to noise suppression and reproducible results. This technology, integrated in a lab‐on‐chip for monitoring cellular growth, is based on a spatial reconstructed imaging technique using electrical impedance tomography.
Ion Beam Modification of ZnO Epilayers: Sequential Processing
Authors: Turos Andrzej , Ratajczak Renata , Mieszczynski Cyprian , Jozwik Przemyslaw , Stonert Anna , Prucnal Slawomir , Heller Rene , Skorupa Wolfgang , von Borany Johannes , Guziewicz Elzbieta
Published: April 2018

Defect agglomeration in ion‐implanted compound semiconductors produces lattice stress eventually causing plastic deformation at sufficiently high fluence. Consequently, a dislocations tangle is formed which can hardly be completely removed by thermal annealing. To solve this problem, a new method of sequential processing has been developed consisting of low fluence ion implantation followed by subsequent annealing. The procedure can be then repeated until the required impurity concentration has been reached without producing excessive damage. Epitaxial ZnO layers are grown using the atomic layer deposition (ALD) technique. Structural changes in ZnO epilayers due to Yb‐ion implantation and subsequent annealing are analyzed by Rutherford backscattering/channeling (RBS/c) and photoluminescence (PL). Correlation between defect transformations and PL efficiency is determined. Increased Yb‐atom optical activation upon sequential processing as compared to the standard single‐step annealing is observed.
A Modified Chemical Imaging Sensor System for Real‐Time pH Imaging of Accelerated Crevice Corrosion of Stainless Steel
Authors: Miyamoto Ko‐ichiro , Sakakita Sakura , Werner Carl Frederik , Yoshinobu Tatsuo
Published: April 2018

The measurement system of a chemical imaging sensor is combined with the circuitry for polarization of a metal test piece. The surface of the metal test piece is brought into contact with the sensor surface forming a crevice of about 12 µm width. The course of initiation and propagation of corrosion are observed as serial images of pH in the crevice. A local change of the pH value down to 2 is observed in synchronization with the change of the anodic current.
Quantized Electron Transport Through Graphene Nanoconstrictions
Authors: Clericò Vito , Delgado‐Notario Juan A. , Saiz‐Bretín Marta , Hernández Fuentevilla Cristina , Malyshev Andrey V. , Lejarreta Juan D. , Diez Enrique , Domínguez‐Adame Francisco
Published: April 2018

Here, the quantization of Dirac fermions in lithographically defined graphene nanoconstrictions is studied. Quantized conductance is observed in single nanoconstrictions fabricated on top of a thin hexamethyldisilazane layer over a Si/SiO2 wafer. This nanofabrication method allows to obtain well defined edges in the nanoconstrictions, thus reducing the effects of edge roughness on the conductance. The occurrence of ballistic transport is proved and several size quantization plateaus are identified in the conductance at low temperature. Experimental data and numerical simulations show good agreement, demonstrating that the smoothening of the plateaus is not related to edge roughness but to quantum interference effects.
Defect Study in CoCrFeMnNi High Entropy Alloy by Positron Annihilation Lifetime Spectroscopy
Authors: Elsayed Mohamed , Krause‐Rehberg Reinhard , Eisenschmidt Christian , Eißmann Nadine , Kieback Bernd
Published: April 2018

Positron annihilation lifetime spectroscopy is applied to study the crystal defects in CoCrFeMnNi high entropy alloy. The material is measured in the as‐received (electro eroded; non‐etched) state; it shows a defect‐related positron lifetime of 220 ps, corresponding most likely to divacancies, with a relatively high concentration. Furthermore, this sample is annealed in the temperature range up to 1000 K and positron lifetime is measured after each annealing step. The average positron lifetime is found to decrease with annealing and reaches 121 ps after annealing at 1000 K, indicating the existence of some remaining defects in the material. To show whether the observed defects are present in the bulk sample or only in the surface area, another sample is deeply etched and shows only one lifetime component of 112 ps, which is assigned to the defect‐free bulk lifetime in this alloy. This study indicated that the investigates high entropy alloy (in etched state) does not contain open‐volume defects within the sensitivity range of positron annihilation. Here, the defects observed in the non‐etched sample are present in the subsurface region, which are assumed to be generated most probably during wire‐erosion of the samples. In addition, X‐ray diffraction results indicate that the crystal structure is FCC with a lattice constant of (3.597 ± 0.002) Å, which is not affected by annealing.
Highly Fluorescent Magnetic Nanobeads with a Remarkable Stokes Shift as Labels for Enhanced Detection in Immunoassays
Authors: Salis Francesca , Descalzo Ana B. , Benito‐Peña Elena , Moreno‐Bondi María C. , Orellana Guillermo
Published: April 2018

Fluorescence immunoassays are popular for achieving high sensitivity, but they display limitations in biological samples due to strong absorption of light, background fluorescence from matrix components, or light scattering by the biomacromolecules. A powerful strategy to overcome these problems is introduced here by using fluorescent magnetic nanobeads doped with two boron‐dipyrromethane dyes displaying intense emission in the visible and near‐infrared regions, respectively. Careful matching of the emission and absorption features of the dopants leads to a virtual Stokes shift larger than 150 nm achieved by an intraparticle Förster resonance energy transfer (FRET) process between the donor and the acceptor dyes. Additionally, the magnetic properties of the fluorescent beads allow preconcentration of the sample. To illustrate the usefulness of this approach to increase the sensitivity of fluorescence immunoassays, the novel nanoparticles are employed as labels for quantification of the widely used Tacrolimus (FK506) immunosuppressive drug. The FRET‐based competitive inhibition immunoassay yields a limit of detection (LOD) of 0.08 ng mL−1, with a dynamic range (DR) of 0.15–2.0 ng mL−1, compared to a LOD of 2.7 ng mL−1 and a DR between 4.1 and 130 ng mL−1 for the immunoassay carried out with direct excitation of the acceptor dye.
Silver‐Assisted Synthesis of Gold Nanorods: the Relation between Silver Additive and Iodide Impurities
Authors: Jessl Sarah , Tebbe Moritz , Guerrini Luca , Fery Andreas , Alvarez‐Puebla Ramon A. , Pazos‐Perez Nicolas
Published: April 2018

Seed‐mediated methods employing cetyltrimethylammonium bromide (CTAB) as a surfactant, and silver salts as additives, are the most common synthetic strategies for high‐yield productions of quality Au nanorods. However, the mechanism of these reactions is not yet fully understood and, importantly, significant lab‐to‐lab reproducibility issues still affect these protocols. In this study, the direct correlation between the hidden content of iodide impurities in CTAB reagents, which can drastically differ from different suppliers or batches, and the optimal concentration of silver required to maximize the nanorods yield is demonstrated. As a result, high‐quality nanorods are obtained at different iodide contents. These results are interpreted based on the different concentrations of CTAB and cetyltrimethylammonium iodide (CTAI) complexes with Ag+ and Au+ metal ions in the growth solution, and their different binding affinity and reduction potential on distinct crystallographic planes. Notably, the exhaustive conversion of CTAI–Au+ to CTAI–Ag+ appears to be the key condition for maximizing the nanorod yield.
Ultrahigh Conductive Copper/Large Flake Size Graphene Heterostructure Thin‐Film with Remarkable Electromagnetic Interference Shielding Effectiveness
Authors: Wang Zhe , Mao Boyang , Wang Qianlong , Yu Jun , Dai Jixiang , Song Rongguo , Pu Zonghua , He Daping , Wu Zhi , Mu Shichun
Published: April 2018

To guarantee the normal operation of next generation portable electronics and wearable devices, together with avoiding electromagnetic wave pollution, it is urgent to find a material possessing flexibility, ultrahigh conductive, and superb electromagnetic interference shielding effectiveness (EMI SE) simultaneously. In this work, inspired by a building bricks toy with the interlock system, we design and fabricate a copper/large flake size graphene (Cu/LG) composite thin film (≈8.8 μm) in the light of high temperature annealing of a large flake size graphene oxide film followed by magnetron sputtering of copper. The obtained Cu/LG thin‐film shows ultrahigh thermal conductivity of over 1932.73 (±63.07) W m−1 K−1 and excellent electrical conductivity of 5.88 (±0.29) × 106 S m−1. Significantly, it also exhibits a remarkably high EMI SE of over 52 dB at the frequency of 1–18 GHz. The largest EMI SE value of 63.29 dB, accorded at 1 GHz, is enough to obstruct and absorb 99.99995% of incident radiation. To the best of knowledge, this is the highest EMI SE performance reported so far in such thin thickness of graphene‐based materials. These outstanding properties make Cu/LG film a promising alternative building block for power electronics, microprocessors, and flexible electronics.
Nanoscale Lacing by Electrons
Authors: Cheng Han‐Wen , Wang Jie , Li Yong‐Jun , Li Jing , Yan Shan , Shan Shiyao , Wang Lingyan , Skeete Zakiya , Zhong Chuan‐Jian
Published: April 2018

The ability to harness the optical or electrical properties of nanoscale particles depends on their assembly in terms of size and spatial characteristics which remains challenging due to lack of size focusing. Electrons provide a clean and focusing agent to initiate the assembly of nanoclusters or nanoparticles. Here an intriguing route is demonstrated to lace gold nanoclusters and nanoparticles in string assembly through electron‐initiated nucleation and aggregative growth of Au(I)‐thiolate motifs on a thin film substrate. This size‐focused assembly is demonstrated by controlling the electron dose under transmission electron microscopic imaging conditions. The Au(I)‐thiolate motifs, in combination with the molecularly mediated alignment, facilitate the interstring electrostatic and intrastring aurophilic interactions, which functions as a molecular template to aid electron‐initiated 1D lacing. The findings demonstrate a hierarchical route for the 1D assemblies with size and spatial tunable catalytic, optical, sensing, and diagnostic properties.
Effect of Submicron‐Scale MnS Inclusions on Hydrogen Trapping and HIC Susceptibility of X70 Pipeline Steels
Authors: Peng Zhixian , Liu Jing , Huang Feng , Hu Qian , Cheng Zhaoyang , Liu Shuai , Cheng Yufeng
Published: April 2018

In this work, the non‐metallic inclusions contained in a trial X70 pipeline steels are characterized by optical microscopy, scanning electron microscopy, energy‐dispersive X‐ray spectrum, and transmission electron microscopy. Statistical analysis is conducted to summarize the size and shape of the inclusions. The hydrogen trapping and the resulting hydrogen‐induced cracking (HIC) susceptibility of the steels are tested. Density functional theory is used to calculate the binding energy of hydrogen at MnS inclusions, and the impact of MnS inclusions on hydrogen trapping and the HIC susceptibility is evaluated. It is found that the majority of submicron scale inclusions are MnS, which serve as irreversible hydrogen traps. The content of the trapped hydrogen can be effectively decreased by controlling the size of MnS inclusions below submicron scale and distributing the inclusions uniformly in the steel. As a result, the susceptibility of the steel to HIC is reduced.
Effect of Oxide Inclusions on the Magnetic Properties of Non‐Oriented Electrical Steel
Authors: Ren Qiang , Zhang Lifeng , Yang Wen
Published: April 2018

A plant experiment is conducted to study the effect of oxide inclusions on the magnetic properties of non‐oriented electrical steel. The morphology, size, and composition of oxide inclusions are investigated by an automated scanning electron microscope. In the liquid steel, the increase of the content of CaO in oxide inclusions promotes the inclusion size and decreases the width of the size distribution. Besides, the viscosity of oxide inclusions plays a key role on the deformation during the hot rolling process at 1000 °C. When the viscosity of inclusions is larger than that of the steel matrix, the oxide inclusions are nearly undeformed. While when the viscosity of inclusions is lower than that of the steel matrix, the inclusions are deformed into chain‐like shape and the elongation ratio increases with the decreasing of viscosity. Additionally, deformed oxide inclusions perform a greater pinning force on the moving of grain boundaries, which is verified by the measured results of the grain size. Thus, in terms of increasing the magnetic properties, the viscosity of oxide inclusions shall be controlled to larger than that of the steel matrix by adjusting the inclusion composition.
High‐Temperature Initial Oxidation Behavior in LDX 2101
Authors: Zhang Yong , Shi Aijuan , Liang Ping , Wang Jian , Meng Haojie , Zhang Caili , Zhang Zhuxia , Han Peide
Published: April 2018

High‐temperature initial oxidation behavior at 1000 °C in LDX 2101 oxidized in a closed element is studied. The samples are investigated using optical microscopy, scanning electron microscopy, energy dispersive spectroscopy, glow discharge optical emission spectroscopy, and Raman spectra. Results show differences in morphology and development of oxides on the two phases. In the initial stage, the oxide on austenite is granular, whereas that on the ferrite region is homogeneous. However, the entire surface is full of chromium oxide. In the austenite phase, oxide gradually changes from Fe2O3 to Cr2O3. By contrast, oxide transforms from Mn2O3 to Fe2O3 and then to Cr2O3 in the ferrite phase. In addition, manganese enrichment is observed in the entire oxidation process.
Learning directed acyclic graph models based on sparsest permutations
Authors: Raskutti Garvesh , Uhler Caroline
Published: April 2018

We consider the problem of learning a Bayesian network or directed acyclic graph model from observational data. A number of constraint‐based, score‐based and hybrid algorithms have been developed for this purpose. Statistical consistency guarantees of these algorithms rely on the faithfulness assumption, which has been shown to be restrictive especially for graphs with cycles in the skeleton. We here propose the sparsest permutation (SP) algorithm, showing that learning Bayesian networks is possible under strictly weaker assumptions than faithfulness. This comes at a computational price, thereby indicating a statistical‐computational trade‐off for causal inference algorithms. In the Gaussian noiseless setting, we prove that the SP algorithm boils down to finding the permutation of the variables with the sparsest Cholesky decomposition of the inverse covariance matrix, which is equivalent toℓ0‐penalized maximum likelihood estimation. We end with a simulation study showing that in line with the proven stronger consistency guarantees, and the SP algorithm compares favourably to standard causal inference algorithms in terms of accuracy for a given sample size. Copyright © 2018 John Wiley & Sons, Ltd.
Notch Signaling Regulates Lgr5+ Olfactory Epithelium Progenitor/Stem Cell Turnover and Mediates Recovery of Lesioned Olfactory Epithelium in Mouse Model
Authors: Dai Qi , Duan Chen , Ren Wenwen , Li Fangqi , Zheng Qian , Wang Li , Li Wenyan , Lu Xiaoling , Ni Wenli , Zhang Yanping , Chen Yan , Wen Tieqiao , Yu Yiqun , Yu Hongmeng
Published: April 2018

The Notch signaling pathway regulates stem cell proliferation and differentiation in multiple tissues and organs, and is required for tissue maintenance. However, the role of Notch in regulation of olfactory epithelium (OE) progenitor/stem cells to maintain tissue function is still not clear. A recent study reported that leucine-rich repeat-containing G-protein-coupled receptor 5 (Lgr5) is expressed in globose basal cells (GBCs) localized in OE. Through lineage tracing in vivo, we found that Lgr5+ cells act as progenitor/stem cells in OE. The generation of daughter cells from Lgr5+ progenitor/stem cells is delicately regulated by the Notch signaling pathway, which not only controls the proliferation of Lgr5+ cells and their immediate progenies but also affects their subsequent terminal differentiation. In conditionally cultured OE organoids in vitro, inhibition of Notch signaling promotes neuronal differentiation. Besides, OE lesion through methimazole administration in mice induces generation of more Notch1+ cells in the horizontal basal cell (HBC) layer, and organoids derived from lesioned OE possesses more proliferative Notch1+ HBCs. In summary, we concluded that Notch signaling regulates Lgr5+ GBCs by controlling cellular proliferation and differentiation as well as maintaining epithelial cell homeostasis in normal OE. Meanwhile, Notch1 also marks HBCs in lesioned OE and Notch1+ HBCs are transiently present in OE after injury. This implies that Notch1+ cells in OE may have dual roles, functioning as GBCs in early development of OE and HBCs in restoring the lesioned OE.
Mechanical behavior of steel fiber‐reinforced self‐compacting concrete corbels after exposure to elevated temperatures
Authors: Abdulhaleem Khamees Nayyef , Gülşan Mehmet Eren , Çevik Abdulkadir
Published: April 2018

The paper presents an experimental study to investigate the effect of steel fiber (SF) on the mechanical behavior of self‐compacting concrete corbels after exposure to elevated temperatures. This research examines the most relevant parameters that influence the behavior of reinforced concrete corbels (RC‐corbels). These parameters comprise of the grade of concrete (medium [C50] and high strength concrete [C80]), the shear span‐to‐depth ratio (0.6 and 0.8), and the reinforcement ratio (0.82 and 1.6%). RC‐corbels were prepared from self‐compacting concrete with a constant percentage of polypropylene fiber of 0.1% and three different SF volume fractions of 0, 0.5, and 1.0%. All RC‐corbels were tested before and after exposure to elevated temperatures (250, 500 and 750 °C). The results were presented in terms of load–deflection curves, crack patterns and failure modes. Results showed that the SFs have a positive effect on load‐carrying capacity and ductility of RC‐corbels both before and after exposure to elevated temperatures.
A review of literature and code formulations for cracking in R/C members
Authors: Lapi Massimo , Orlando Maurizio , Spinelli Paolo
Published: April 2018

Cracking in R/C members is a complex phenomenon characterized by high scattering, mainly affected by concrete in tensile zone. The aim of this paper is to evaluate the effectiveness of formulas for crack width prediction developed in last decades. First, an historical review of available literature models is presented and discussed. Second, the progress and missteps, which have characterized the development of international code provisions, are shown. Finally, a comprehensive comparison between predicted crack widths and experimental data is performed. Some formulas more than others provide mean values of crack width in good agreement with experimental data; nevertheless, predictions are always very scattered, as ratios between theoretical and experimental values have a coefficient of variation not lower than 30%. Results show that the prediction capacity does not necessarily increase as the cracking model is refined.
Shaking table model test and numerical analysis of a long‐span cantilevered structure
Authors: Chen Shiming , Ge Kang , Xue Weichen , Lin Yingru , Lin Gao
Published: April 2018

This paper presents an earthquake‐resistance study program of a long‐span cantilevered story building. The program consists of a shaking table test study and nonlinear seismic analysis using finite element modeling technique. A 1/30 scale model of the prototype structure was designed and manufactured and then tested via the shaking table facility. Dynamic responses of the prototype structure under different earthquake excitation loadings were simulated. Dynamic properties, acceleration, and deformation responses of the scale down model under different intensity levels of earthquake were studied. The dynamic behavior, cracking pattern, and the likely governing failure mechanism of the structure were analyzed and discussed as well. The seismic responses of the prototype building were deduced and analyzed in terms of the similitude law. Furthermore, elaborate finite element models were established, and nonlinear numerical analysis of the prototype structure was conducted. The errors in the seismic response of the structure caused by structural simplification of scale down modeling are found small, and the dynamic behavior of the structure was not altered in the earthquake excitations. This test study provides a benchmark to calibrate the finite element model and a tentative guide in seismic design of such long‐span cantilevered story buildings.
Experimental study on steel reinforced concrete columns subjected to combined bending–torsion cyclic loading
Authors: Chen Shicai , Peng Wei , Yan Weiming
Published: April 2018

An experimental investigation and analysis of the mechanical behavior of steel reinforced concrete (SRC) columns under combined bending–torsion cyclic loads is presented in this paper. Seven SRC columns with the same cross‐sectional construction were tested under various torsion moment to bending moment ratios and axial load levels. The effect of the torsion to bending moment ratio on the failure characteristics, hysteretic behavior, bearing capacity, and deformation characteristics of the SRC columns was studied. Results indicate that both bending and torsion bearing capacity are reduced under combined bending and torsion loads and that the torsion–bending ratio is the key parameter that determines the failure mode of the SRC columns. Based on the tests results, an equation expressing the interaction curve between the bending and torsion is proposed.
Glabridin induces apoptosis and cell cycle arrest in oral cancer cells through the JNK1/2 signaling pathway
Authors: Chen Chang‐Tai , Chen Yi‐Tzu , Hsieh Yi‐Hsien , Weng Chia‐Jui , Yeh Jung‐Chun , Yang Shun‐Fa , Lin Chiao‐Wen , Yang Jia‐Sin
Published: April 2018

Glabridin, a flavonoid extracted from licorice (Glycyrrhiza glabra), possesses various biological properties, including anticancer activities. However, the effect of glabridin on oral cancer cell apoptosis and the underlying molecular mechanisms has not been elucidated. In this study, we demonstrated that glabridin treatment significantly inhibits cell proliferation in human oral cancer SCC‐9 and SAS cell lines. Flow cytometric assays demonstrated that glabridin induced several features of apoptosis, such as sub‐G1 phase cell increase and phosphatidylserine externalization. Furthermore, glabridin induced apoptosis dose‐dependently in SCC‐9 cells through caspase‐3, −8, and −9 activation and poly (ADP‐ribose) polymerase cleavage. Moreover, glabridin increased the phosphorylation of the extracellular signal–regulated kinase, p38, and c‐Jun N‐terminal kinase (JNK) pathways in a dose‐dependent manner. Moreover, the inhibition of the JNK1/2 inhibitor significantly reversed the glabridin‐induced activation of the caspase pathway. In conclusion, our findings suggest that glabridin induces oral cancer cell apoptosis through the JNK1/2 pathway and is a potential therapeutic agent for oral cancer.
Clustering of nonstationary data streams: A survey of fuzzy partitional methods
Authors: Abdullatif Amr , Masulli Francesco , Rovetta Stefano
Published: April 2018

Data streams have arisen as a relevant research topic during the past decade. They are real‐time, incremental in nature, temporally ordered, massive, contain outliers, and the objects in a data stream may evolve over time (concept drift). Clustering is often one of the earliest and most important steps in the streaming data analysis workflow. A comprehensive literature is available about stream data clustering; however, less attention is devoted to the fuzzy clustering approach, even though the nonstationary nature of many data streams makes it especially appealing. This survey discusses relevant data stream clustering algorithms focusing mainly on fuzzy methods, including their treatment of outliers and concept drift and shift.

This article is categorized under

Technologies > Machine Learning

Technologies > Computational Intelligence

Fundamental Concepts of Data and Knowledge > Data Concepts
Double network hydrogel for tissue engineering
Authors: Gu Zhipeng , Huang Keqing , Luo Yan , Zhang Laibao , Kuang Tairong , Chen Zhou , Liao Guochao
Published: April 2018

Double network (DN) hydrogels, a kind of promising soft and tough hydrogels, are produced by two unique contrasting networks with designed network entanglement burst into the field of materials science as versatile functional systems for a very broad range of applications. A part of the DN hydrogels is characterized by extraordinary mechanical properties providing efficient biocompatible and high strength for holding considerable promise in tissue engineering. Following DN hydrogels principles and consideration of biomedical applications, we provide an overall view of the present various DN hydrogels and look forward to the future of DN hydrogels for tissue engineering. In this review, the preparation methods, structure, properties, current situation, and challenges are mainly discussed for the purpose of tissue engineering.

This article is categorized under:

Implantable Materials and Surgical Technologies > Nanomaterials and Implants

Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and Replacement
The Influence of the Counterions [AsF6]– and [GeF6]2– on the Structure of the [ClSO2NH3]+ Cation
Authors: Leitz Dominik , Stierstorfer Karin , Morgenstern Yvonne , Zischka Florian , Kornath Andreas J.
Published: April 2018

Chlorosulfonamide reacts in the superacidic solutions HF/GeF4 and HF/AsF5 under the formation of ([ClSO2NH3]+)2[GeF6]2– and [ClSO2NH3]+[AsF6]–, respectively. The chlorosulfonammonium salts were characterized by X‐ray single crystal structure analysis as well as vibrational spectroscopy and discussed together with quantum chemical calculations. ([ClSO2NH3]+)2[GeF6]2– crystallizes in the triclinic space group P1 with one formula unit in the unit cell. [ClSO2NH3]+[AsF6]– crystallizes in the monoclinic space group P21/n with four formula units in the unit cell. Dependent on the counterion, [AsF6]– or [GeF6]2–, considerable structural differences of the [ClSO2NH3]+ cation are observed. Furthermore, the hitherto unknown X‐ray single crystal structure of chlorosulfonamide is determined in the course of this study. Chlorosulfonamide crystallizes in the orthorhombic space group Pmc2 with four formula units per unit cell.
Analysis of Ores and its Purified Constituents by γ‐Spectrometry with Calculation of Uranium Isotopic Atom, Mass, and Activity Ratios
Authors: Abdel‐Rahman Mohamed A. E. , Abu Shady Hoda , El‐Mongy Sayed A.
Published: April 2018

The physical verifications, that the national and international inspectors carry out in order to perform a credibility control, often consist in the measurement of physical quantities, related to the declared nuclear material properties, by Non‐destructive Assay (NDA). Analysis of ores and its purified constituent's samples has been carried out in this work using non‐destructive gamma assay technique. The spectrometer based on HpGe detector and its electronics was calibrated using standard IAEA multi‐lines gamma sources. The efficiency calibration curve was plotted for broad gamma energies; 50–2600 keV. The gamma transition of 235U (143.7, 163.3, 185.7, and 205.3 keV) and 238U (63, 766.3, and 1001.03 keV) were used for qualitative and quantitative assay of the samples. The specific activities of the samples were calculated based on the determined efficiency, branching ratio (emission probability per disintegration), mass of sample and count rate of the characteristics gamma transitions of uranium isotopes at fixed geometrical conditions. A simplified equation was derived for calculation of 235U atom ratios. The results of calculation show natural origin of the analyzed samples; around 0.72 %. Where, the anthropogenic 236U was not detected at all in the spectra. The uranium activity ratios (235U/238U) were calculated based on the measured activity. The uranium isotopic mass and total uranium content of the investigated samples were also calculated. The results obtained are depicted, tabulated and discussed in comparison with recent published national and international works.
New closed‐form solutions for functionally graded longitudinally vibrating bar
Authors: Elishakoff Isaac , Armstrong Hailey , Hashemi Javad
Published: April 2018

In this paper we present new closed‐form solutions for functionally graded longitudinally vibrating bar. The modulus of elasticity is represented as a continuous function varying along the axial coordinate. It is postulated that the mode shape represents the sixth order polynomial. Six closed form solutions are presented: four for clamped‐clamped bar, and two for clamped‐free bar.
Conformal anomaly of generalized form factors and finite loop integrals
Authors: Chicherin Dmitry , Sokatchev Emery
Published: April 2018

Abstract

We reveal a new mechanism of conformal symmetry breaking at Born level. It occurs in generalized form factors with several local operators and an on-shell state of massless particles. The effect is due to hidden singularities on collinear configurations of the momenta. This conformal anomaly is different from the holomorphic anomaly of amplitudes. We present a number of examples in four and six dimensions. We find an application of the new conformal anomaly to finite loop momentum integrals with one or more massless legs. The collinear region around a massless leg creates a contact anomaly, made visible by the loop integration. The anomalous conformal Ward identity for an ℓ−loop integral is a 2nd-order differential equation whose right-hand side is an (ℓ − 1)−loop integral. It could serve as a new useful tool to find/test analytic expressions for conformal integrals. We illustrate this point with several examples of known integrals. We propose a new differential equation for the four-dimensional scalar double box.
Improved positivity bounds and massive gravity
Authors: de Rham Claudia , Melville Scott , Tolley Andrew J.
Published: April 2018

Abstract

Theories such as massive Galileons and massive gravity can satisfy the presently known improved positivity bounds provided they are weakly coupled. We discuss the form of the EFT Lagrangian for a weakly coupled UV completion of massive gravity which closely parallels the massive Galileon, and perform the power counting of corrections to the scattering amplitude and the positivity bounds. The Vainshtein mechanism which is central to the phenomenological viability of massive gravity is entirely consistent with weak coupling since it is classical in nature. We highlight that the only implication of the improved positivity constraints is that the EFT cutoff is lower than previous assumed, and discuss the observable implications, emphasizing that these bounds are not capable of ruling out the model contrary to previous statements in the literature.
Segmented strings coupled to a B-field
Authors: Vegh David
Published: April 2018

Abstract

In this paper we study segmented strings in AdS3 coupled to a background two-form whose field strength is proportional to the volume form. By changing the coupling, the theory interpolates between the Nambu-Goto string and the SL(2, ℝ) Wess-Zumino-Witten model. In terms of the kink momentum vectors, the action is independent of the coupling and the classical theory reduces to a single discrete-time Toda-type theory. The WZW model is a singular point in coupling space where the map into Toda variables degenerates.
Dark matter “transporting” mechanism explaining positron excesses
Authors: Kim Doojin , Park Jong-Chul , Shin Seodong
Published: April 2018

Abstract

We propose a novel mechanism to explain the positron excesses, which are observed by satellite-based telescopes including PAMELA and AMS-02, in dark matter (DM) scenarios. The novelty behind the proposal is that it makes direct use of DM around the Galactic Center where DM populates most densely, allowing us to avoid tensions from cosmological and astrophysical measurements. The key ingredients of this mechanism include DM annihilation into unstable states with a very long laboratory-frame life time and their “retarded” decay near the Earth to electron-positron pair(s) possibly with other (in)visible particles. We argue that this sort of explanation is not in conflict with relevant constraints from big bang nucleosynthesis and cosmic microwave background. Regarding the resultant positron spectrum, we provide a generalized source term in the associated diffusion equation, which can be readily applicable to any type of two-“stage” DM scenarios wherein production of Standard Model particles occurs at completely different places from those of DM annihilation. We then conduct a data analysis with the recent AMS-02 data to validate our proposal.
Raummuster: Demographischer Wandel und Klimawandel in deutschen Städten
Authors: Dieckhoff Viola Schulze , Becker Dennis , Wiechmann Thorsten , Greiving Stefan
Published: April 2018

Climate change and demographic change interact. Impacts in the context of climate change do not solely result from climate change and climate variability. They are a consequence of interrelations between climate and social change. Diverse settlement structures as well as a heterogeneous population lead towards small-scale sensitivities in the face of climate variability and extreme events. Who is sensitive, at what time and at what location become central questions of urban and spatial planning, aiming at sustainable cities and communities, good health and well-being as well as reduced inequalities. Demography is, next to politics, culture, economy, education or religion, the most substantial factor regarding these questions due to its profound knowledge and methodological toolbox on population dynamics. Therefore, the article aims at analysing the spatial patterns of demographic and climate change. The integrated assessment of climatic and demographic indicators reveals major spatial patterns for Germany: urban growth in warmer climate types as well as dismantling and vacancy in drier climate types. In both cases, an extreme change in population volume and/or structure takes place parallel to an increasing climatic exposure. This leads towards growing adaption needs. Planning science and practice needs to revise its taboos (manage retreat) and premises (internal before external development) as well as integrate new findings (adaptive strategies) and technical innovations (digital information sources).
Determinanten des Online-Einkaufs – eine empirische Studie in sechs nordrhein-westfälischen Stadtregionen
Authors: Wiegandt Claus-C. , Baumgart Sabine , Hangebruch Nina , Holtermann Linus , Krajewski Christian , Mensing Matthias , Neiberger Cordula , Osterhage Frank , Texier-Ast Verena , Zehner Klaus , Zucknik Björn
Published: April 2018

Retail trade is no longer occurring in urban centres or suburban malls on the edge of cities, exclusively. It increasingly takes place online. The aim of this study is to examine the determining factors for in-store and online shopping respectively. The results are based on a survey of approximately 2,900 people in the six North Rhine-Westphalian city regions of Aachen, Bochum, Bonn, Dortmund, Münster and Cologne. Depending on the distance to each particular urban centre, 26 neighbourhoods were chosen to conduct the questionnaires. In all six city regions it is apparent that instead of spatial factors selected demographic and socio-economic forces determine buyer behaviour. While gender, age and lifestyles are important in terms of online shopping, income is no longer an influencing parameter.
Die Relevanz kleiner Gemeinden und kleinteiliger Flächen für die Innenentwicklung. Ein quantitatives Monitoring am Beispiel Deutschlands
Authors: Schiller Georg , Blum Andreas , Oertel Holger
Published: April 2018

The limitation of land use and the protection of soil is an important target set in European and national sustainability strategies. To this end, the use of brownfields, vacant and underutilised sites within existing settlement structures for urban development, frequently called infill development, is a primary strategy. This paper presents the results of a nationwide survey to generate reliable data on the potential for infill development in German cities and towns. In contrast to earlier studies, in particular infill development potential in small communities and small-scale potential, usually on vacant lots, are focused and discussed with regard to their relevance for land-saving settlement-policy making. The data generated allow to determine a reliable range of overall infill development potential per capita of at least 15 m2. Often underestimated, the survey also reveals, that more than a quarter of infill development potential is located in smaller communities below 5.000 inhabitants, which were not included in earlier surveys. With respect to lot sizes the results also show that small-scale potential on vacant lots makes up more than half of the overall potential. It is thus recommended that policy making towards sustainable land use put more emphasis on small-scale land uses and awareness rising in smaller communities which clearly tend to underestimate their infill potential.
Biological Reconstruction of Varus Deformity in Primary Total Knee Replacement Using Bone Graft and Description of a New Technique
Authors: Singh Luthra Jatinder , Habsi Salim A.L.
Published: April 2018

Peripheral bony defects of the tibia can be seen in patients with osteoarthritis of the knee. These defects must be corrected at the time of total knee replacement to ensure correct placement and alignment of the components.

We describe a new technique for correcting large tibial defect by using bone graft, where the uncontained defects were converted to contained defects using bone graft and the contained defect was impacted with cancellous bone. Between 2006 and 2010, 48 cases of primary total knee arthroplasty were reconstructed using autologous bone graft. Of 48 cases, five cases had large tibial defect and were treated with the new technique. Collapse was seen in one knee at 5 months postoperative. The rest of the patients showed improvement in total knee score and limb alignment.

We now use this technique to treat large tibial defect during total knee replacement.
Never forget a face? The rise of ‘live’ body-worn cameras
Authors: van Schelle Fernande
Published: April 2018

“IC1 male. Jeans. Red hooded top. Blue cap. Last seen running towards…” Seriously? In 2018 first responders should not still be working from vague at best two-way radio descriptions: law enforcement can do so much better than that.
Good vibrations: accessing ‘smart’ systems by touching any solid surface
Authors: Liu Jian , Wang Chen , Chen Yingying , Saxena Nitesh
Published: April 2018

The process of people authenticating themselves to verify their identity is now commonplace across many areas of our daily life. It's no longer just users of touchscreen devices like mobile phones – the growing use of smart systems means people need to identify themselves to access many other devices and daily activities, like entering their apartment, driving a vehicle and using smart appliances.
Albian infaunal Pholadomyida (Cretaceous Bivalvia), Comanchean Carbonate Shelf, Texas
Authors: Scott Robert W. , Claggett Bradley W.
Published: April 2018

Species of the megaorder Poromyata, although common and relatively diverse in Albian–lower Cenomanian Comanchean strata in Texas and northern Mexico, have been neglected as biostratigraphic markers and paleoecological indicators. Since 1852, more than a dozen species have been identified asHomomyaAgassiz, order Pholadomyida, superfamily Pholadomyoidea orPleuromyaAgassiz, order Pholadida, superfamily Pleuromyoidea. Because valve morphologies of the two genera are similar in many ways, casts are difficult to separate. Statistical analysis of key morphological properties objectively defines species concepts and assesses synonymies. Eight species are retained inHomomya; four are synonymized with these. Two species are provisionally retained in “Homomya” although they differ significantly. One species is reassigned toLiopistha (Sergipemya) alta(Roemer, 1852).Pleuromya henselli(Hill, 1893) is reassigned toPanopea.

Homomyid species range from upper Aptian to lower Cenomanian of the Comanchean Series in Texas and Mexico. Their ranges vary in duration from one million years up to eight million years. These infaunal suspension feeders occupied calcareous mud and carbonate shelf substrates. Two sets of species are distinct morphotypes: a smaller-sized set ofH. knowltoniHill, 1895;H. tarrantensisPerkins, 1961;H. tlahualiloensisPerkins, 1961; andH. kellumiPerkins, 1961 and a larger-sized set ofH. cymbiformisPerkins, 1961;H. austinensisShattuck, 1903;H. vulgarisShattuck, 1903;H. budaensisWhitney, 1911; andH. auroraensisPerkins, 1961. Two end-member morphotypes are represented by the “streamlined”Homomya knowltoni, which is an elongate, slightly inflated form with a relatively high umbo, and the cylindricalHomomya budaensis, which is a very elongate, tubular, inflated form with a very low umbo.
Winners and Losers of the Ballot: Electronic vs. Traditional Paper Voting Systems in Brazil
Authors: Schneider Rodrigo , Senters Kelly N.
Published: April 2018

Scholars concur that free and fair elections are essential for proper democratic functioning, but our understanding of the political effects of democratic voting systems is incomplete. This article mitigates the gap by exploiting the gradual transformation of voting systems and ballot structures in Brazil’s 1998 executive elections to study the relationship between voting systems and viable and nonviable candidates’ vote shares, using regression discontinuity design. It finds that the introduction of electronic voting concentrated vote shares among viable candidates and thus exhibited electoral bias. We posit that this result occurred because viable candidates were better able to communicate the information that electronic voters needed to cast valid ballots than were their nonviable counterparts. The article uses survey data to demonstrate that electronic voters responded to changes in ballot design and internalized the information viable candidates made available to them.
Descartes’s Indefinitely Extended Universe
Authors: REID JASPER
Published: April 2018

Descartes believed the extended world did not terminate in a boundary: but why? After elucidating Descartes’s position in §1, suggesting his conception of the indefinite extension of the universe should be understood as actual but syncategorematic, we turn in §2 to his argument: any postulation of an outermost surface for the world will be self-defeating, because merely contemplating such a boundary will lead us to recognise the existence of further extension beyond it. In §3, we identify the fundamental assumption underlying this argument by comparing Descartes’s and Malebranche’s respective conceptions of the ontological status of modes of extension.
Ap-ADIC HERMITIAN MAASS LIFT
Authors: BERGER TOBIAS , KLOSIN KRZYSZTOF
Published: April 2018

ForK, an imaginary quadratic field with discriminant −DK, and associated quadratic Galois character χK, Kojima, Gritsenko and Krieg studied a Hermitian Maass lift of elliptic modular cusp forms of levelDKand nebentypus χKvia Hermitian Jacobi forms to Hermitian modular forms of level one for the unitary groupU(2, 2) split overK. We generalize this (under certain conditions onKandp) to the case ofp-oldforms of levelpDKand character χK. To do this, we define an appropriate Hermitian Maass space for general level and prove that it is isomorphic to the space of special Hermitian Jacobi forms. We then show how to adapt this construction to lift a Hida family of modular forms to ap-adic analytic family of automorphic forms in the Maass space of levelp.
Low fertility, fecundity and numbers of mated female offspring explain the lower reproductive success of the parasitic mite Varroa destructor in African honeybees
Authors: Nganso Beatrice T. , Fombong Ayuka T. , Yusuf Abdullahi A. , Pirk Christian W. W. , Stuhl Charles , Torto Baldwyn
Published: April 2018

Although Varroa destructor is the most serious ecto-parasite to the honeybee, Apis mellifera L., some honeybee populations such as Apis mellifera scutellata in Kenya can survive mite infestations without treatment. Previously, we reported that grooming behaviour could be a potential tolerant mechanism expressed by this honeybee subspecies towards mite infestation. However, both hygienic and grooming behaviours could not explain the lower mite-infestation levels recorded in these colonies. Here, we investigated the involvement of other potential resistant mechanisms including suppression of mite reproduction in worker brood cells of A. m. scutellata to explain the low mite numbers in their colonies. High infertility rates (26–27%) and percentages of unmated female offspring (39–58%) as well as low fecundity (1.7–2.2, average offspring produced) were identified as key parameters that seem to interact with one another during different seasons to suppress mite reproduction in A. m. scutellata colonies. We also identified offspring mortality in both sexes and absence of male offspring as key factors accounting for the low numbers of mated daughter mites produced in A. m. scutellata colonies. These results suggest that reduced mite reproductive success could explain the slow mite population growth in A. m. scutellata colonies.