bluuebunny/crossref_metadata_2025 huggingface dataset:
Angiogenic and Osteogenic Synergy of Human Mesenchymal Stem Cells and Human Umbilical Vein Endothelial Cells Cocultured on a Nanomatrix
Authors: Chen Jun , Deng Lily , Porter Catherine , Alexander Grant , Patel Dhruv , Vines Jeremy , Zhang Xixi , Chasteen-Boyd David , Sung Hak-Joon , Li Yi-Ping , Javed Amjad , Gilbert Shawn , Cheon Kyounga , Jun Ho-Wook
Published: October 2018

To date, bone tissue regeneration strategies lack an approach that effectively provides an osteogenic and angiogenic environment conducive to bone growth. In the current study, we evaluated the osteogenic and angiogenic response of human mesenchymal stem cells (hMSCs) and green fluorescent protein-expressing human umbilical vein endothelial cells (GFP-HUVECs) cocultured on a self-assembled, peptide amphiphile nanomatrix functionalized with the cell adhesive ligand RGDS (PA-RGDS). Analysis of alkaline phosphatase activity, von Kossa staining, Alizarin Red quantification, and osteogenic gene expression, indicates a significant synergistic effect between the PA-RGDS nanomatrix and coculture that promoted hMSC osteogenesis. In addition, coculturing on PA-RGDS resulted in enhanced HUVEC network formation and upregulated vascular endothelial growth factor gene and protein expression. Though PA-RGDS and coculturing hMSCs with HUVECs were each previously reported to individually enhance hMSC osteogenesis, this study is the first to demonstrate a synergistic promotion of HUVEC angiogenesis and hMSC osteogenesis by integrating coculturing with the PA-RGDS nanomatrix. We believe that using the combination of hMSC/HUVEC coculture and PA-RGDS substrate is an efficient method for promoting osteogenesis and angiogenesis, which has immense potential as an efficacious, engineered platform for bone tissue regeneration.
Magnetization Manipulation of a Flexible Magnetic Sensor by Controlled Stress Application
Authors: Kwon Joon-Hyun , Kwak Won-Young , Cho Beong Ki
Published: October 2018

Spin-based electronic devices on polymer substrates have been intensively investigated because of several advantages in terms of weight, thickness, and flexibility, compared to rigid substrates. So far, most studies have focused on maintaining the functionality of devices with minimum degradation against mechanical deformation, as induced by stretching and bending of flexible devices. Here, we applied repetitive bending stress on a flexible magnetic layer and a spin-valve structure composed of Ta/NiFe/CoFe/Cu/Ni/IrMn/Ta on a polyimide (PI) substrate. It is found that the anisotropy can be enhanced or weakened depending upon the magnetostrictive properties under stress. In the flat state after bending, due to residual compressive stress, the magnetic anisotropy of the positive magnetostrictive free layer is weakened while that of the pinned layer with negative magnetostriction is enhanced. Thus, the magnetic configuration of the spin-valve is appropriate for use as a sensor. Through the bending process, we design a prototype magnetic sensor cell array and successfully show a sensing capability by detecting magnetic microbeads. This attempt demonstrates that appropriate control of stress, induced by repetitive bending of flexible magnetic layers, can be effectively used to modify the magnetic configurations for the magnetic sensor.
Visualizing large choroidal blood flow by subtraction of the choriocapillaris projection artifacts in swept source optical coherence tomography angiography in normal eyes
Authors: Maruko Ichiro , Kawano Taizo , Arakawa Hisaya , Hasegawa Taiji , Iida Tomohiro
Published: October 2018

Optical coherence tomography angiography (OCTA) seems not to image the choroidal blood flow pattern in the normal individual because of the OCT light attenuation. Our purpose in the current study was to visualize the large choroidal blood flow pattern after subtraction of the choriocapillaris projection artifact in normal eyes non-invasively by swept source (SS) OCTA. Sixty-one eyes of 45 individuals (19 men, 26 women) without ocular disease were examined by SS-OCTA (AngioPlex Elite 9000, Zeiss, Germany). A 12 × 12 mm macular area was scanned. Subfoveal choroidal thickness (SCT) was measured, and the choroidal blood flow pattern in a slab of 30 µm width at one-half of SCT was analyzed. In examining the choroidal blood flow pattern, a slab that was between 30 to 60 µm posterior to the retinal pigment epithelium, in which the choriocapillaris blood flow was most clearly imaged, was used for the subtraction of the projection artifacts from the choriocapillaris on the stromal area of choroid. The ratio (%) of the choroidal blood flow area in the whole choroidal region was calculated after binarization. Thirty-four eyes of 27 individuals (12 men, 15 women) were also examined by spectral domain OCTA (SD-OCTA). After the subtraction, the middle and large choroidal blood flow were clearly visible in SS-OCTA in all eyes. The mean SCT was 297 ± 61 µm, and the mean ratio of the choroidal blood flow area was 27.3 ± 8.2%, which was significantly correlated with SCT (R = 0.738, P < 0.01). SD-OCTA did not show the choroidal blood flow pattern. In conclusion, removal of the projection artifacts of choriocapillaris can make the choroidal blood flow visible in SS-OCTA of normal eyes. Because the ratio of choroidal blood flow area was correlated with SCT, the choroidal blood flow might be an important factor related to the choroidal thickness.
Author Correction: Multiscale framework for simulation-guided growth of 2D materials
Authors: Momeni Kasra , Ji Yanzhou , Zhang Kehao , Robinson Joshua A. , Chen Long-Qing
Published: October 2018

The Acknowledgments section of the original version of this Article did not acknowledge all of the relevant funding sources. This has now been corrected in the HTML and PDF versions of the Article.
A conjugated carbon-dot–tyrosinase bioprobe for highly selective and sensitive detection of dopamine
Authors: Tang Zhongdi , Jiang Kai , Sun Shan , Qian Sihua , Wang Yuhui , Lin Hengwei
Published: October 2018

A conjugated carbon-dot–tyrosinase bioprobe was first designed and applied for sensitive and selective dopamine detection in human serum.
Computational design, synthesis and utilization of a magnetic molecularly imprinted polymer on graphene oxide nanosheets for highly selective extraction and determination of buprenorphine in biological fluids and tablets
Authors: Ganjavi Farideh , Ansari Mehdi , Kazemipour Maryam , Zeidabadinejad Leila
Published: October 2018

A magnetic MIP for the selective extraction of buprenorphine (BUP) from real plasma and urine samples and tablets based on computational design as a novel procedure has been developed.
Oxidative coupling of enolates using memory of chirality: an original enantioselective synthesis of quaternary α-amino acid derivatives
Authors: Mambrini Antonin , Gori Didier , Guillot Régis , Kouklovsky Cyrille , Alezra Valérie
Published: October 2018

A memory of chirality strategy allowed the first enantioselective oxidative heterocoupling of enolates.
A charge-separated diamondoid metal–organic framework
Authors: Thapa Sheela , Hettiarachchi Eshani , Dickie Diane A. , Rubasinghege Gayan , Qin Yang
Published: October 2018

Metal–organic framework with diamondoid structure constructed with precisely placed tetrahedral borate anions and copper(i) cations.
An efficient strategy for improving the luminescent sensing performance of a terbium(iii) metal–organic framework towards multiple substances
Authors: Wang Xiaoning , Li Jia-Luo , Jiang Chenggang , Hu Peng , Li Bao , Zhang Tianle , Zhou Hong-Cai
Published: October 2018

A new luminescent Ln-MOF-based sensor with hydrolytic stability has been successfully prepared.
Coinage metal complexes of NHC-stabilized silyliumylidene ions
Authors: Frisch Philipp , Inoue Shigeyoshi
Published: October 2018

The first coinage metal complexes (M = Cu, Ag, Au) of an N-heterocyclic carbene-stabilized silyliumylidene ion are reported.
Stability of the polar faces in KTiOPO4 crystalline layers grown by liquid phase epitaxy
Authors: Peña Alexandra , Ménaert Bertrand , Debray Jérôme , Canalias Carlota , Boulanger Benoît
Published: October 2018

Kinetic studies show that the non-equivalent polar faces, (001) and (001̅), of KTiOPO4 crystals have different growth rates and stabilities.
Synthesis, structure and temperature sensing of a lanthanide-organic framework constructed from a pyridine-containing tetracarboxylic acid ligand
Authors: Zhao Dian , Wang Huizhen , Qian Guodong
Published: October 2018

A high sensitive, thermostable mixed lanthanide metal–organic framework, Eu0.19Tb0.81PDDI, was developed as a self-calibrated thermometer effective in the high temperature range of 313 to 473 K.
Maximizing NMR signal per unit time by facilitating the e–e–n cross effect DNP rate
Authors: Leavesley Alisa , Jain Sheetal , Kamniker Ilia , Zhang Hui , Rajca Suchada , Rajca Andrzej , Han Songi
Published: October 2018

Dynamic nuclear polarization (DNP) efficiency is critically dependent on the properties of the radical, solvent, and solute, where electron spin clusters will shorten nuclear spin relaxation and enhance CE-DNP.
Insights into catalytic roles of noble-metal-free catalysts CoxSy for reduction of 4-nitrophenol
Authors: Zhou Rongmei , Yang Xiaoyan , Zhang Peng , Yang Lixia , Liu Chengwei , Liu Dan , Gui Jianzhou
Published: October 2018

The enhanced catalytic activity of Co9S8 results from the better H adsorption ability and the faster electron-migration efficiency of multivalent Co.
Tuning phase transitions of aqueous protein solutions by multivalent cations
Authors: Matsarskaia Olga , Roosen-Runge Felix , Lotze Gudrun , Möller Johannes , Mariani Alessandro , Zhang Fajun , Schreiber Frank
Published: October 2018

Cation-specific characteristics such as ion radius and hydration effects strongly influence the phase behaviour of protein-salt solutions.
Topologically close-packed characteristic of amorphous tantalum
Authors: Wu Zhizhou , Mo Yunfei , Lang Lin , Yu Aibing , Xie Quan , Liu Rangsu , Tian Zean
Published: October 2018

The structural evolution of tantalum during rapid cooling was investigated extensively, and its strong GFA originates from the intrinsic topologically close-packed structures that are ubiquitous in metallic melts and possible the essential units in metallic glasses.
Distinguishing ionic and radical mechanisms of hydroxylamine mediated electrocatalytic alcohol oxidation using NO–H bond dissociation energies
Authors: Dao Rina , Zhao Chenxuan , Yao Jia , Li Haoran
Published: October 2018

An idea is proposed to sort N-oxyl radicals with respect to their mechanisms of electrocatalytic alcohol oxidation by knowing the NO–H bond dissociation energies of their precursors.
In situ growth of heterostructured Sn/SnO nanospheres embedded in crumpled graphene as an anode material for lithium ion batteries
Authors: Wang Jing-Feng , He Dan-Nong
Published: October 2018

Heterostructured Sn/SnO core–shell nanospheres embedded in graphene have been prepared by heating tin oleate coated on the surface of sodium carbonate crystals, and they exhibit excellent electrochemical performance for LIBs.
Mixed chelating ligands used to regulate the luminescence of Ln(iii) complexes and single-ion magnet behavior in Dy-based analogues
Authors: Wang Hai-Ling , Ma Xiong-Feng , Zou Hua-Hong , Wang Kai , Li Bo , Chen Zi-Lu , Liang Fu-Pei
Published: October 2018

The organic ligands 5,7-dibromo-2-methyl-8-quinolinol (L1), 1,10-phenanthroline (L2), and 5,7-dichloro-2-methyl-8-quinolinol (L3) were used to react with Dy(NO3)3·6H2O under solvothermal conditions at 80 °C to obtain the complexes [Dy(L1)3(H2O)] (1), [Dy(L2)2(NO3)3] (2), and [Dy(L3)3(H2O)] (3), respectively.
Cold atmospheric plasma activated water as a prospective disinfectant: the crucial role of peroxynitrite
Authors: Zhou Renwu , Zhou Rusen , Prasad Karthika , Fang Zhi , Speight Robert , Bazaka Kateryna , Ostrikov Kostya (Ken)
Published: October 2018

Here the possibility of plasma-activated water being a green disinfectant, whose bioactivity is closely linked to peroxynitrite generation, was demonstrated.
High-spin enforcement in first-row metal complexes of a constrained polyaromatic ligand: synthesis, structure, and properties
Authors: Chen Lizhu , Dulaney Hunter A. , Wilkins Branford O. , Farmer Sarah , Zhang Yanbing , Fronczek Frank R. , Jurss Jonah W.
Published: October 2018

The coordination chemistry of a rigid tetradentate polypyridyl ligand has been developed with first-row transition metals Mn(ii), Fe(ii), Co(ii), Ni(ii), and Zn(ii).
Design, synthesis, and characterization of an Fe(ii)-polymer of a redox non-innocent, heteroatomic, polydentate Schiff's base ligand: negative differential resistance and memory behaviour
Authors: Oberoi Deepa , Dagar Parveen , Shankar Uday , Vyas Giriraj , Kumar Anil , Sahu Satyajit , Bandyopadhyay Anasuya
Published: October 2018

Complete characterization and memristive study of the electrochemically active, novel Fe(ii)-polymer of a fluorescence active conjugated, hexadentate ligand.
Deactivation and regeneration of in situ formed bismuth-promoted platinum catalyst for the selective oxidation of glycerol to dihydroxyacetone
Authors: Ning Xiaomei , Zhan Liang , Wang Hongjuan , Yu Hao , Peng Feng
Published: October 2018

Glycerol oxidation over a Pt catalyst can be effectively enhanced by a Bi additive in terms of activity and 1,3-dihydroxyacetone (DHA) selectivity.
Self-doped nontoxic red-emitting Mg–N-embedded carbon dots for imaging, Cu(ii) sensing and fluorescent ink
Authors: Bhati Anshu , Anand Satyesh Raj , Saini Deepika , Khare Prateek , Dubey Prashant , Sonkar Sumit Kumar
Published: October 2018

The easy fabrication of self-doped red-emitting CD is described here where the addition of external dopant materials is either can be avoided or minimized.
Atropisomeric meroterpenoids with rare triketone-phloroglucinol-terpene hybrids from Baeckea frutescens
Authors: Hou Ji-Qin , Wang Bao-Lin , Han Chao , Xu Jian , Wang Zhe , He Qi-Wei , Zhang Pei-Lin , Zhao Shu-Min , Pei Xin , Wang Hao
Published: October 2018

Compounds 1–4 represent the first examples of natural atropisomeric meroterpenoids with a rare triketone-phloroglucinol-terpene skeleton.
Simple and sensitive colorimetric detection of a trace amount of 2,4,6-trinitrotoluene (TNT) with QD multilayer-modified microchannel assays
Authors: Hu Tao , Sang Wen , Chen Ke , Gu Hongxi , Ni Zhonghua , Liu Shaoqin
Published: October 2018

Two-colored quantum dot (QD) multilayer-decorated microchannel assays were fabricated for the visual detection of ultratrace levels of TNT.
Protective effects of low-intensity pulsed ultrasound on aluminum overload-induced cerebral damage through epigenetic regulation of brain-derived neurotrophic factor expression
Authors: Li Juan , Zhang Dong-dong , Wang Chao-qing , Shi Miao , Wang Liang-liang
Published: October 2018

In consideration of its noninvasive administration and endogenous stimulation property, the enhancement of brain-derived neurotrophic factor (BDNF) via low-intensity pulsed ultrasound (LIPUS) could be a novel strategy for aluminum (Al) overload-induced cerebral damage. LIPUS was pre-treated 7 days before concomitantly given with aluminum chloride (AlCl3) daily for a period of 42 days. Morris water maze and elevated plus maze were performed to analyze spatial learning and memory. Western Blot and immunoprecipitation were used to detect BDNF and histone acetylation of histone H3 lysine 9 (H3K9) and histone H4 lysine 12 (H4K12) in the hippocampus. Assay of malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH), and glutathione peroxidase (GSH-Px) indicated the extent of oxidative damages. Aluminium exposure in rats can cause attenuated spatial learning and memory, followed by up-regulated histone deacetylase 6 (HDAC6) expression, down-regulated H3K9 and H4K12 acetylation at the PIII and PIV promoter of BDNF, all of which will eventually inhibit BDNF expression. LIPUS can recover reduced cognitive function by restoring histone acetylation and BDNF expression, accompanied with increased SOD, GSH, and GSH-Px activity. LIPUS treatment might alleviate aluminium exposure-induced cognitive decline by acetylation regulation of BDNF expression and reducing oxidative stress in the hippocampus.
Clusters partition and zonal voltage regulation for distribution networks with high penetration of PVs
Authors: Ding Jinjin , Zhang Qian , Hu Shijun , Wang Qunjing , Ye Qiubo
Published: October 2018

Integration of distributed generation (DG) at large scale with high penetration challenges the radial structure of the traditional distribution networks and the effectiveness of the conventional voltage regulation methods. In this study, the clusters partitioning and voltage regulation are researched. The modified electrical distance is introduced. An effective method, based on spectral clustering algorithm, is proposed for the partitioning of the DG network via the judgement of critical load buses. Two‐stage voltage regulation optimisation is realised in each sub‐community. The optimal objects are the minimal voltage fluctuation and the network loss of the distributed network. The independent variables are reactive‐power absorption and active‐power curtailment for each controllable photovoltaic node. An advanced particle swarm optimisation algorithm is applied to the voltage regulation for the sub‐communities. After a case study of the IEEE 33‐bus system, a regional distribution network in Anhui province of China is analysed. Simulation results indicate that the node voltages are stabilised with the improvement of power quality employing the proposed clusters partitioning method and zonal power control scheme.
Parameter estimation and output feedback stabilization for the linear Korteweg-de Vries equation with disturbed boundary measurement
Authors: Jia Chaohua , Guo Wei , Luo Diao
Published: October 2018

This paper is concerned with the parameter estimation and boundary feedback stabilization for the linear Korteweg-de Vries equation posed on a finite interval with the boundary observation at the right end and the non-collocated control at the left end. The boundary observation suffers from some unknown disturbance. An adaptive observer is designed and the adaptive laws of the parameters are obtained by the Lyapunov method. The resulted closed-loop system is proved to be well-posed and asymptotically stable in case that the length of the interval is not critical. Moreover, it is shown that the estimated parameter converges to the unknown parameter. As a by-product, a hidden regularity result is proved.
Representation of the Matrix for Conversion between Triangular Bezier Patches and Rectangular Bezier Patches
Authors: Sabancıgil Pembe , Kara Mustafa
Published: October 2018

In this paper we studied Bezier surfaces that are very famous techniques and they are widely used in the area of Computer Aided Geometric Design. Mainly there are two kinds of Bezier surfaces which are classified as rectangular and triangular Bezier patches. In this paper we will give a simple representation for the conversion matrix which converts one type to another type in one step.
Use And Comparison of Topis And Electre Methods In Personnel Selection
Authors: Şenel Bilgin , Şenel Mine , Aydemir Gizem
Published: October 2018

One of the most important function of human resources is personnel selection process. This process should be done professionally, in a short time and with minimum cost. After personnel selection process, performance of the hired person is very important for the permanence and success of the company. From this point of view, the aim of this study is to select a personnel among the candidates efficiently, with minimum cost and within a short time in one of the leading companies of Turkey in automotive sector. In order to select the right personnel all criterias which has great impact on blue collar worker selection was decided and these criterias are weighted. From the candidate pool of automotive company, appropriate candidates were selected by using TOPSIS AND ELECTRE method which are multi-criteria decision making methods
Reproducing kernel functions for the generalized Kuramoto-Sivashinsky equation
Authors: Akgül Ali , Akgül Esra Karatas , Korhan Sahin , Inc Mustafa
Published: October 2018

Reproducing kernel functions are obtained for the solution of generalized Kuramoto–Sivashinsky (GKS) equation in this paper. These reproducing kernel functions are valuable in the reproducing kernel Hilbert space method. They will be useful for interested researchers.
Example of A Kinetic Mathematical Modeling in Food Engineering
Authors: ERTEKİN Özlem
Published: October 2018

Mathematical modeling of biochemical, chemical reaction processes facilitates understanding. The kinetics of these reaction processes can be analyzed mathematically and kinetics are presented as systems of differential equations. Mathematical model of a reaction kinetic is studied in this study. Bernoulli-Sub equation function method is used in this study. This example can be new model for food engineering applications.
Complex Acoustic Gravity Wave Behaviors to a Mathematical Model Arising in Nonlinear Mathematical Physics
Authors: Akturk Tolga , Sulaiman Tukur Abdulkadir , Baskonus Haci Mehmet , Bulut Hasan
Published: October 2018

In this article, we utilize the powerful sine-Gordon expansion method (SGEM) in constructing some new solutions to the (2 + 1)-dimensional Boiti-Leon-Pempinelli equation by using the Mathematica software. We successfully obtain some new travelling solutions bearing some new structures such as trigonometric function, exponential function and hyperbolic function structures. We claim that some of our results are complex in structure. All the solutions obtained verified the the (2 + 1)-dimensional Boiti-Leon-Pempinelli equation. To illustrate our results, present the numerical simulation of all the obtained solutions in this study by selecting appropriate values of the parameters. Furthermore, we give the physical interpretation of all the graphics. We also give the physical meaning to some of the obtained results in this study.
Al-Khwârizmî's Place and Importance in the History of Mathematics
Authors: DURAN Serbay , SAMANCI Hüseyin
Published: October 2018

The aim of this study is to introduce Muḥammad ibn Mûsâ al-Khwârizmî and his works in terms of history of mathematics and mathematics education. Muḥammad ibn Musa al-Khwârizmî an Iraqi Muslim scholar and it is the first of the Muslim mathematicians who have contributed to this field by taking an important role in the progress of mathematics in his own period. He found the concept of Algorithm in mathematics. In some circles, he was given the nickname Abu Ilmi’l-Hâsûb (the father of the account). He carried out important studies in algebra, triangle, astronomy, geography and map drawing. Algebra has carried out systematic and logical studies on the solution of inequalities at second level in the development of the algebra. He with all these studies have contributed to mathematical science and today was a guide to the works done in the field of mathematics.
A Survey on Photo Forgery Detection Methods
Authors: Gurunlu Bilgehan , Ozturk Serkan
Published: October 2018

In recent years, digital image forgery detection has become one of the hardest studying area for researchers investigations in the field of information security and image processing. Image forgery detection methods can be divided into two extensive groups such as Active methods and Passive (Blind) methods. Active methods have been used data hiding techniques like watermarking and digital signatures. Passive forensic methods (or Blind) use image statistics or they investigate the attributes of the image to determine the forgeries. Passive detection techniques are also split into three branches; image splicing, image retouching, copy-move. Such image forgery detection methods are focus of this paper.
Determining strength of rubble masonry of bridges’ supports being in operation
Authors: Zasukhin Ilya , Bokarev Sergey
Published: October 2018

The purpose of this article is to create a methodology for determining the design strength of rubble masonry of bridge supports meeting the modern safety requirements for transport structures. The article contains data on the use of the rubble masonry in solid supports of railway bridges. Development of methodology of determining the permissible stresses on the rubble masonry, and the practice of applying the design strength of the rubble masonry in regulatory documents are considered. Analysis of the research works is carried out, according to which the design strength of the rubble masonry of solid supports is determined when calculating the load-bearing capacity. The experimental data of European scientists in the field of determining the strength characteristics of stone masonries are considered. A domestic method for determining the design values of strength characteristics for building materials used in transport construction is presented. The main deficiencies of the existing method for determining the design strength of rubble masonry are defined and suggestions are made for its clarification. The article concludes with the formulation of tasks required to be solved for clarification of strength characteristics of the operated railway supports made of rubble masonry.
Development of approach to improvement of urban traffic flow diagram
Authors: Burlutsky Andrey , Pushkareva Galina , Kirgisarova Elena
Published: October 2018

The result of generalized analysis of Russian and foreign studies focused on urban transportation systems demonstrate that the existing methods of forming schemes of passenger transport routes only partially account interaction of transport flows and urban highways. Usually, insufficient attention is paid to optimization criteria that allow performing comprehensive analysis of rationality of transport route schemes. It is defined that speed is one of the key optimization criteria for transport systems that accounts specific feature of traffic flow organization on a street network of a big city and its state with regard to the use of traffic. An approach to reasonable scheduling of route scheme reorganization was developed basing on the routing experience, it allows accounting the factors that defines technical state of a road network and characteristics of transport flows.
Optimization of technical solutions for pilot hole drilling in soil
Authors: Danilov Boris , Smolyanitskiy Boris
Published: October 2018

The paper discusses approaches to improvement of equipment for borehole drilling with a predetermined trajectory in construction of underground utility systems and facilities. Piercing method allows implementing dry drilling of boreholes with small diameter using simple technical equipment. The methods used when preparing the research are analysis, generalization, and experimental research methods. Outcomes of the research include evidence that increase in performance of vibro-impact piercing is possible not only due to higher impact energy, but also due to optimization of interaction between the operating tool and soil. Combination of dynamic action by impact pulses and static forces applied to the drilling equipment enables to enhance performance of impact pulse action and increase the drilling speed. Accuracy of the borehole trajectory can be provided by using dynamic stabilizers or correcting the drilling direction due to asymmetrical tool shape in combination with the torque moment of a drilling equipment. The study formulates requirements to design of a drilling unit for directed pilot hole drilling by dynamic piercing method. The design of an improved pneumatic tool installed in front of the drill string and equipped with asymmetrical front head is described. Experimental research results are given on the process of a borehole drilling using the described tool.
Methods of determination of forces in the “wheel-rail” system
Authors: Sych Tatyana , Kolomeets Andrey
Published: October 2018

Increase in the volume of heavy traffic on railways updates the requirements for ensuring transportation safety in conditions of continuous increasing in axle loads on the track. The purpose of the study is to review methods for determining the dynamic forces arising from interaction between the wheel and the rail during rolling stock movement. The numerical method is used to determine the values of relative strain of the rail web at the transducers locations. Model verification and estimation of the calculation accuracy for several methods of determining forces in the “wheel-rail” system has been performed. Methods for determining the loads arising in the wheel and rail system, as well as the results of calculating the three load components were obtained. Simulation tests of the proposed forces control method have been performed.
The Effect of Lubrication on the Vibration of Roller Bearings
Authors: Yusof N.F.M. , Ripin Z.M.
Published: October 2018

Proper lubrication is crucial to ensure smooth operation in machineries. In rolling bearing, the improper lubrication may induce high friction and vibration level due to metal to metal contact between the rolling elements. In this study, the roller bearings with and without lubrication are investigated. the natural surface degradation of the roller bearing is monitored and the surface roughness is measured for the lubricant film thickness calculation. the film thickness is determined by the Hamrock-Dowson equation which showed that the grease lubricated bearing operated under the elastro-hydrodynamic lubrication, with the ratio of lubrication film thickness to the surface roughness of λ in the range of 0.9 to 3.65. the un-lubricated bearing was damaged after 20 minutes whereas the grease lubricated bearing continued to operate for 6600 minutes. the observation under microscope showed that the surface underwent smoothening process where the surface roughness decreases initially (running-in state) followed by roughening at the steady state where the surface roughness increases. At damage, the value of λ = 0.9 can be associated with the high level of the bearing vibration. the increase of vibration level becomes rapid at the critical value of λ = 1.6. As such the overall vibration level of the bearing can be related to the surface degradation and low film thickness.
Sound and Vibration Damping Properties of Nonwoven Flax Reinforced Acrylic Based Polyester Composites
Authors: Ali WMA Wan Mamat , Ooi L.E. , Ishak Z. A Mohd.
Published: October 2018

This paper presents the sound and vibration damping properties of nonwoven flax reinforced acrylic based polyester composites. This research attempt to solve the problem of synthetic fibre which caused environmental problems. the goal of is study to characterize the sound absorption and damping properties of the natural fibre at difference thickness and pressure. the nonwoven flax reinforced acrylic based polyester composites are produced by using moulding machines at different compression pressures that are 10, 20 and 30 bars. the thicknesses of samples used in this study are 2 mm and 3 mm. the measurement of sound absorption of the material is carried out using impedance tube. For the sample with 2 mm thickness, the result shows that the maximum sound absorption of 0.93 was observed at frequency of 853 Hz and pressure of 20 bars. Damping values are calculated and measure for each sample. the result shows that damping factor is obtained is 0.039 and 0.052 for thickness materials of 2mm and 3mm.
Effect of Step Height On the Aeration Efficiency of Cascade Aerator System Using Particle Image Velocimetry
Authors: Azman A. , Zawawi M. H. , Hassan N. H. , Abas A. , Razak N. A. , Mazlan A. Z. A. , Mohd Remy Rozainy M.A.Z
Published: October 2018

Aeration is an important parameter in water filtration system as it allows the transfer of oxygen to water through turbulence effect which subsequently increases air entrainment in the water. For water treatment application, aeration efficiency is measured to ensure continuous re-oxygenation of the unfiltered water. Aside from aeration, this paper also studies the flow patterns through the use of particle image velocimetry (PIV) setup. Through the use of real scale down physical model laboratory study is performed using PIV to obtain the velocity profile. These velocity profiles will then be used to calculate the aeration efficiency of the water in a cascade aerator system. Based on the findings, the aeration efficiency obtained from the PIV experiment has a maximum value at the lowest point of the cascade aerator system with a value of 0.0139 due to increase in mass flow rate as it moves through the steps with velocity of 0.418 m/s. Therefore, in the design of a cascade aerator system, it is advisable to increase the number of steps since it will increase the aeration efficiency of the system.
Preface
Authors: Morozov A.
Published: October 2018

In the preface, we present a short overview of the papers included in the issue of Mathematical Modelling of Natural Phenomena ‘Modelling in Ecology, Epidemiology and Evolution’.
Initial Layer Analysis for a Linkage Density in Cell Adhesion Mechanisms
Authors: Milisic Vuk
Published: October 2018

In this paper we present a non local age structured equation involved in cell motility modeling [5, 9, 11]. It describes the evolution of a density of linkages of a point submitted to adhesion. It depends on an asymptotic parameter ɛ representing the characteristic age of linkages. Here we introduce a new initial layer term in the asymptotic expansion with respect to ɛ. This improves error estimates obtained in [5]. Moreover, we study the convergence of the time derivative of this density and show how a singular term appears when ɛ goes to zero. We show convergence, in the tight topology of measures, to the time derivative of the limit solution and a Dirac mass supported on the initial half-axis. In order to illustrate these results, numerical simulations are performed and compared to the asymptotic expansion for various values of ɛ.
Verification of 2D × 2D and Two-Species Vlasov-Poisson Solvers,
Authors: Barsamian Yann , Bernier Joackim , Hirstoaga Sever A. , Mehrenberger Michel
Published: October 2018

In [2], 1D×1D two-species Vlasov-Poisson simulations are performed by the semi-Lagrangian method. Thanks to a classical first order dispersion analysis, we are able to check the validity of their simulations; the extension to second order is performed and shown to be relevant for explaining further details. In order to validate multi-dimensional effects, we propose a 2D × 2D single species test problem that has true 2D effects coming from the sole second order dispersion analysis.

Finally, we perform, in the same code, full 2D × 2D non linear two-species simulations with mass ratio 0:01, and consider the mixing of semi-Lagrangian and Particle-in-Cell methods.
Implementation of Fetal Cardiac Guidelines for the Routine Second-Trimester Heart Examination: A Feasibility Study
Authors: Gerede Angeliki , Sotiriadis Alexandros , Karavida Aikaterini , Petousis Stamatios , Mikos Themistoklis , Assimakopoulos Efstratios , Tarlatzis Basil C , Athanasiadis Apostolos P
Published: October 2018

Purpose This study aimed to explore the feasibility of implementation of the ISUOG 2013 guidelines on routine second-trimester examination of the fetal heart.

Materials and Methods This was a prospective study in 357 women with singleton pregnancy undergoing their routine second-trimester scan. The fetal heart was examined using B-mode in different planes according to the guidelines. Potential maternal and fetal factors that can affect the rates of diagnostic-quality imaging for each of the recommended views were tested, using regression analysis. The intra- and interobserver agreement was analyzed in stored video loops.

Results Most cardiac structures could be successfully examined with rates at or close to 100 %. Structures with a successful examination rate of ≤ 85 % included the ventricular wall fine details (55.2 %), tricuspid valve insertion (82.6 %), aortic root with clear walls (77.9 %), pulmonary artery walls (65.8 %) and clear view of the great artery walls (66.7 %). Common factors affecting the likelihood of successful examination of these structures included maternal BMI, skin-to-crux distance and the orientation of the cardiac axis. A post-hoc analysis indicated that a lack of pre-defined criteria for diagnostic quality was a constant reason for the interobserver variation.

Conclusion Most of the cardiac views can be consistently and reliably obtained, with maternal habitus being the primary factor limiting the quality of visualization. As offline interpretation may be subjective, using pre-defined quality criteria for the assessment of the images might improve interrater agreement.
Value of Ultrasonography in the Diagnosis of Inguinal Hernia – A Retrospective Study
Authors: Maisenbacher Tanja , Kratzer Wolfgang , Formentini Andrea , Schmidberger Julian , Kaltenbach Tanja , Henne-Bruns Doris , Graeter Tilmann , Hillenbrand Andreas
Published: October 2018

Purpose The diagnosis of an inguinal hernia is usually made clinically. Precise imaging appears to be necessary when the clinical examination is inconclusive. The aim of this study was to determine the diagnostic value of ultrasonography for inguinal hernias and whether it influences the decision for or against surgery.

Materials and Methods This study was a single-center retrospective study carried out from January 2012 to December 2016. All 326 patients had undergone ultrasound scanning of the groin as part of the diagnostic workup. Besides surgical findings being the gold standard, follow-up data and alternative ultrasound diagnoses were considered as references, allowing us to assess the accuracy of negative ultrasound findings as well.

Results The findings on ultrasonography were positive in 248 patients and negative in 78 patients. In addition to 201 operated patients, we were able to validate a further 40 patients by means of a questionnaire and the alternative ultrasound diagnoses. The correlation with all three references resulted in a sensitivity of 97 %, a specificity of 77 %, a positive predictive value of 95 %, and a negative predictive value of 87 %.

Conclusion Ultrasonography is an accurate method for evaluating inguinal hernias. High sensitivity makes it particularly suitable for ruling out an inguinal hernia when the findings are negative. An ultrasound scan carried out in addition to clinical examination can therefore help to determine the right indication for surgical intervention.
Mesenchymale Stammzellen: Tumorfördernde oder -hemmende Eigenschaften – Ein aktueller Überblick
Authors: Scherzad Agmal , Taeger Johannes , Gehrke Thomas Eckhard , Hagen Rudolf , Kleinsasser Norbert , Hackenberg Stephan
Published: October 2018

Eine multimodale Tumortherapie richtet sich nicht nur gegen die Tumorzellen, sondern beeinflusst auch das tumorumgebende Stroma. Das Tumorstroma beherbergt
verschiedene nicht-maligne Zellen, unter anderem Fibroblasten, Immunzellen, aber auch mesenchymalen Stammzellen (MSC). MSC haben die Fähigkeit der Migration in
Richtung Tumorgewebe. Welche Einflüsse MSC auf Tumorzellen ausüben wird in der gängigen Literatur kontrovers diskutiert. Die meisten Publikationen berichten von
tumorfördernden Eigenschaften der MSC, welche über vier Hauptmechanismen ermöglicht werden: Die Sekretion löslicher Mediatoren verbunden mit
Zell-Zell-Kontakten, die Transdifferenzierung der MSC in tumorassoziierte Fibroblasten, die Verbesserung der Neoangiogenese und zuletzt die Einleitung einer
Immunsuppression durch MSC. In dieser Übersicht wird über den aktuellen Stand der Literatur referiert.
Instrumente in der Unfallchirurgie, Orthopädie und Gynäkologie
Authors: Wagenhäuser Kirsten , Wagenhäuser Karl-Heinz
Published: October 2018

Im fünften Teil unserer Serie zeigen wir Ihnen einige Instrumente, die in der Unfallchirurgie, Orthopädie und Gynäkologie hauptsächlich zur Anwendung kommen.
Typische fassende und schneidende Instrumente aus der Viszeralchirurgie haben wir bereits im letzten Artikel vorgestellt, diese werden natürlich in allen
chirurgischen Bereichen in den unterschiedlichsten Ausführungen und Größen verwendet.
Die transabdominale, praeperitoneale Leistenhernienreparation
Authors: Köller Katharina , Münich Monika , Fackeldey Volker
Published: October 2018

Die transabdominale, praeperitoneale (Netz-)Plastik ist das in Deutschland am häufigsten genutzte Verfahren zur Reparation einer Leistenhernie. Dieser
minimalinvasive Eingriff liefert hervorragende Ergebnisse und ist bei korrekter Präparation mit sehr wenigen Komplikationen verbunden. Er ermöglicht eine
schnelle Rekonvaleszenz und stellt die uneingeschränkte körperliche Belastbarkeit der Patienten wieder her.
Do Hospitals with a Higher Level of Maternal Care Designation Have Better Maternal Outcomes?
Authors: Srinivas Sindhu , Kozhimannil Katy , Hung Peiyin , Attanasio Laura , Jou Judy , Grobman William
Published: October 2018

Background A recent document by the American Congress of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine introduced the concept of uniform levels of maternal care (LMCs).

Objective We assessed LMC across hospitals and measured their association with maternal morbidity, focusing on women with high-risk conditions.

Study Design We collected data from hospitals from May to November 2015 and linked survey responses to Statewide Inpatient Databases (SID) hospital discharge data in a retrospective cross-sectional study of 247,383 births admitted to 236 hospitals. Generalized logistic regression models were used to examine the associations between hospitals' LMC and the risk of severe maternal morbidity. Stratified analyses were conducted among women with high-risk conditions.

Results High-risk pregnancies were more likely to be managed in hospitals with higher LMC (p < 0.001). Women with cardiac conditions had lower odds of maternal morbidity when delivered in level I compared with level IV units (adjusted odds ratio: 0.29; 95% confidence interval: 0.08–0.99; p = 0.049). There were no other significant associations between the LMC and severe maternal morbidity.

Conclusion A higher proportion of high-risk pregnancies were managed within level IV units, although there was no overall evidence that these births had superior outcomes. Further prospective evaluation of LMC designation with patient outcomes is necessary to determine the impact of regionalization on maternal outcomes.
Are Women with a History of Low PAPP-A at Risk for Adverse Perinatal Outcomes in a Subsequent Pregnancy?
Authors: Zafman Kelly , Getrajdman Chloe , Arnold Melanie , Stone Joanne
Published: October 2018

Objective To determine if patients with a history of low pregnancy-associated plasma protein A (PAPP-A) in an initial pregnancy are at higher risk for adverse obstetric outcomes in a subsequent pregnancy.

Study Design This was a retrospective cohort study in patients who underwent first trimester screening for PAPP-A in two consecutive pregnancies. Two groups were examined: patients who had low PAPP-A in the first pregnancy followed by normal PAPP-A in the second pregnancy and patients who had recurrent low PAPP-A. Maternal and neonatal outcomes were compared between the groups, with the primary outcome being intrauterine growth restriction (IUGR) or preeclampsia.

Results A total of 124 patients were included, representing 248 pregnancies. Ninety-two (74.2%) patients had normal PAPP-A in the second pregnancy, and 32 (12.9%) patients had recurrent low PAPP-A. Patients with recurrent low PAPP-A had a higher rate of IUGR or preeclampsia compared with patients with normal PAPP-A in the second pregnancy but this was not significantly different (12.5 vs. 10.9%, p = 0.51). There were no significant differences for all other outcomes.

Conclusion Among patients with a history of low PAPP-A, patients with normal PAPP-A in the subsequent pregnancy have a similar risk of adverse neonatal outcomes compared with patients with recurrent low PAPP-A.
Recurrent synchronization of coupled oscillators with spontaneous phase reformation
Authors: Jeon Jong-ha , Kim Pilwon
Published: October 2018

Self-organizing and spontaneous breaking are seemingly opposite phenomena and hardly captured in a single model. We develop a second order Kuramoto model with phase-induced damping which shows phase locking together with spontaneous synchrony breaking and reformation. In a relatively large regime where the interacting force and the damping ratio are of the same order, the dynamics of the oscillators alternates in an irregular cycle of synchronization, formation-breaking, and reorganization. While the oscillators keep coming back to phase-locked states, their phase distribution repeatedly reforms. Also, the interevent time between bursty deviation from the synchronization states follows a power-law distribution, which implies that the synchronized states are maintained near a tipping point.
Bayesian calibration of force-fields from experimental data: TIP4P water
Authors: Dutta Ritabrata , Brotzakis Zacharias Faidon , Mira Antonietta
Published: October 2018

Molecular dynamics (MD) simulations give access to equilibrium structures and dynamic properties given an ergodic sampling and an accurate force-field. The force-field parameters are calibrated to reproduce properties measured by experiments or simulations. The main contribution of this paper is an approximate Bayesian framework for the calibration and uncertainty quantification of the force-field parameters, without assuming parameter uncertainty to be Gaussian. To this aim, since the likelihood function of the MD simulation models is intractable in the absence of Gaussianity assumption, we use a likelihood-free inference scheme known as approximate Bayesian computation (ABC) and propose an adaptive population Monte Carlo ABC algorithm, which is illustrated to converge faster and scales better than the previously used ABCsubsim algorithm for the calibration of the force-field of a helium system. The second contribution is the adaptation of ABC algorithms for High Performance Computing to MD simulations within the Python ecosystem ABCpy. This adaptation includes a novel use of a dynamic allocation scheme for Message Passing Interface (MPI). We illustrate the performance of the developed methodology to learn posterior distribution and Bayesian estimates of Lennard-Jones force-field parameters of helium and the TIP4P system of water implemented for both simulated and experimental datasets collected using neutron and X-ray diffraction. For simulated data, the Bayesian estimate is in close agreement with the true parameter value used to generate the dataset. For experimental as well as for simulated data, the Bayesian posterior distribution shows a strong correlation pattern between the force-field parameters. Providing an estimate of the entire posterior distribution, our methodology also allows us to perform the uncertainty quantification of model prediction. This research opens up the possibility to rigorously calibrate force-fields from available experimental datasets of any structural and dynamic property.
Integrated diagnostic and data analysis system of the C-2W advanced beam-driven field-reversed configuration plasma experiment
Authors: Thompson M. C. , Schindler T. M. , Mendoza R. , Gota H. , Putvinski S. , Binderbauer M. W. ,   TAE Team
Published: October 2018

The new C-2W experiment (also called Norman) at TAE Technologies, Inc. studies the evolution of field-reversed configuration (FRC) plasmas sustained by neutral beam injection. Data on the FRC plasma performance are provided by a comprehensive suite of diagnostics that includes over 700 magnetic sensors, four interferometer systems, multi-chord far-infrared polarimetry, two Thomson scattering systems, ten types of spectroscopic measurements, multiple fast imaging cameras with selectable atomic line filters, bolometry, reflectometry, neutral particle analyzers, and fusion product detectors. Most of these diagnostic systems are newly built using experience and data from the preceding C-2U experiment to guide the design process. A variety of commercial and custom acquisition electronics collect over 4000 raw signals from the C-2W diagnostics. These data are processed into physics results using a large-scale database of diagnostics metadata and analysis software, both built using open-source software tools.