bluuebunny/crossref_metadata_2025 huggingface dataset:
A Calculation Method for Power System Frequency Deviation Considering Intensity of Turbulence
Authors: TAMURA JUNJI , KAWAMATA KAZUKI , TAKAHASHI RION , UMEMURA ATSUSHI , KIMURA MAMORU , THET AUNG KO
Published: June 2017

As more and more wind farms are installed in power systems around the world, frequency fluctuations due to output power variations have become a serious problem. Various countermeasures for the problem, such as battery systems, have been investigated. It is very important to evaluate the magnitude of the frequency fluctuations in order to design compensating systems. This paper presents a new and simple method to evaluate the expected value of the frequency deviation due to variations in wind farm output, which is based on the intensity of turbulence and annual probability distribution for the wind speed.
Need for speed: Hard information processing in a high‐frequency world
Authors: Zhang S. Sarah
Published: June 2017

I study the role of high‐frequency traders (HFTs) and non‐high‐frequency traders (nHFTs) in transmitting hard price information from the futures market to the stock market using an index arbitrage strategy. Using intraday transaction data with HFT identification, I find that HFTs process hard information faster and trade on it more aggressively than nHFTs. In terms of liquidity supply, HFTs are better at avoiding adverse selection than nHFTs. Consequently, HFTs enhance the linkage between the futures and stock markets, and significantly contribute to information efficiency in the stock market by reducing the delay between the stock and the futures markets.
Progress and policy implication of the Insurance Programs for Catastrophic Diseases in China
Authors: Mao Wenhui , Zhang Luying , Chen Wen
Published: June 2017

The State Council encouraged the involvement of commercial insurance companies (CICs) in the development of the Insurance Program for Catastrophic Diseases (IPCD), yet its implementation has rarely been reported. We collected literature and policy documentation and conducted interviews in 10 cities with innovative IPCD policies to understand the details of the implementation of IPCD. IPCDs are operated at the prefectural level in 14 provinces, while in 4 municipalities and 6 provinces, unified IPCDs have been implemented at higher levels. The contribution level varied from 5% to 10% of total Basic Medical Insurance (BMI) funds or CNY10‐35 per beneficiary in 2015. IPCD provides an additional 50% to 70% reimbursement rate for the expenses not covered by BMI with various settings in different locations. Two models of CIC operation of IPCD have been identified according to the financial risks shared by CICs. Either the local department of Human Resources and Social Security or a third party performs assessments of the IPCD operation, service quality, and patients' satisfaction. A number of IPCDs have been observed to use 1% to 5% of the funds as a performance‐based payment to the CIC(s). CIC involvement in operating the IPCD raises concerns regarding the security of the information of beneficiaries. Developing appropriate data sharing mechanisms between the local department of Human Resources and Social Security and CICs is still in progress. In conclusion, the IPCD relieves the financial burden on patients by providing further reimbursement, but its benefit package remains limited to the BMI reimbursable list. CICs play an important role in monitoring and supervising health service provision, yet their capacity for actuarial services or risk control is underdeveloped.
A study of regulatory policies and relevant issues concerning electronic cigarette use in Taiwan
Authors: Jiang Tzuu Hwa , Cheng Li Min , Hawkins Matthew A.
Published: June 2017

Recent technological innovations have increased the amount of tobacco products available to smokers. In particular, electronic cigarettes, sometimes call e‐cigarettes, have received substantial attention as their sales have rapidly increased. Electronic cigarettes were invented in China and now have become prevalent worldwide. Electronic cigarettes can be considered fashionable and come in numerous flavors; accordingly, many young adults and students have begun to use e‐cigarettes. However, like traditional tobacco products, e‐cigarettes have negative influences on human health. After e‐cigarettes were introduced into Taiwan, they have not been effectively managed and regulated because of insufficient supporting measures. Related legislation in developed countries can serve as a reference for Taiwan. For this study, the development of e‐cigarettes is described and a theoretical analysis was performed from the administration and legal perspectives. In addition to clarifying related problems and offering measures to prevent students from using e‐cigarettes, we propose suggestions to help governments improve their strategies to protect students' health.
The association of hospital governance with innovation in Taiwan
Authors: Yang Chen‐Wei , Yan Yu‐Hua , Fang Shih‐Chieh , Inamdar Syeda Noorein , Lin Hsien‐Cheng
Published: June 2017

Hospitals in Taiwan are facing major changes and innovation is increasingly becoming a critical factor for remaining competitive. One determinant that can have a significant impact on innovation is hospital governance. However, there is limited prior research on the relationship between hospital governance and innovation. The purpose of this study is to propose a conceptual framework to hypothesize the relationship between governance mechanisms and innovation and to empirically test the hypotheses in hospital organizations. We examine the relationship between governance mechanisms and innovation using data on 102 hospitals in Taiwan from the Taiwan Joint Commission on Hospital Accreditation and Quality Improvement. We model governance mechanisms using board structure, information transparency and strategic decision‐making processes. For our modeling and data analysis we use measurement and structural models. We find that in hospital governance, information transparency and strategic decision making did impact innovation. However, governance structure did not. To facilitate innovation, hospital boards can increase information transparency and improve the decision‐making process when considering strategic investments in innovative initiatives. To remain competitive, hospital boards need to develop and monitor indices that measure hospital innovation to ensure ongoing progress.
How to evaluate the quality of coarse‐resolution DEM‐derived drainage networks
Authors: Sousa Thâmara Martins Ismael , Paz Adriano Rolim
Published: June 2017

The quality of digital elevation model (DEM)‐derived river drainage networks (RDNs) is influenced by DEM quality, basin physical characteristics, scale, and algorithms used; these factors should not be neglected. However, few research studies analyse the different evaluation approaches used in the literature with respect to adequacy, meaning of the results, advantages, and limitations. Focusing on coarse‐resolution networks, this paper reviews the use of these techniques and offers new insights on these issues. Additionally, we propose adaptations for selected metrics and discuss distinct interpretations for the evaluation of RDNs derived at different spatial resolutions (1, 5, 10, 20, and 30 km) considering the Uruguay River basin (206,000 km2) as a case study. The results demonstrate that lumped basin/river characteristics and basin delineation analysis should not be used as evaluation criteria for RDN quality; however, some of these metrics offer useful complementary information. Percentage of the DEM‐derived RDN within a uniform buffer placed around a river network considered as reference and mean separation distance between these two networks are more suitable metrics, but the former is insensitive to serious errors. The change in reference from a fine‐scale network to a coarse‐resolution manual tracing network significantly augments the discrepancy of these largest errors when the mean distance metric was applied, and visual comparison analysis is necessary to interpret the results for other metrics. We recommend the use of the mean distance metric in combination with a detailed visual assessment, the importance of which increases as the resolution coarsens. In both cases, the impact of network quality can be further refined by quantifying the basin shape and river length errors.
Optimization and transferability of non‐electrostatic repulsion in the polarizable density embedding model
Authors: Hršak Dalibor , Olsen Jógvan Magnus Haugaard , Kongsted Jacob
Published: June 2017

Embedding techniques in combination with response theory represent a successful approach to calculate molecular properties and excited states in large molecular systems such as solutions and proteins. Recently, the polarizable embedding model has been extended by introducing explicit electronic densities of the molecules in the nearest environment, resulting in the polarizable density embedding (PDE) model. This improvement provides a better description of the intermolecular interactions at short distances. However, the electronic densities of the environment molecules are calculated in isolation, which results in overestimation of the non‐electrostatic repulsion, thereby requiring a scaling of this term. In this work, an optimal scaling factor for the non‐electrostatic repulsion term is examined by comparing intermolecular interaction energies obtained with embedding techniques to reference interaction energies calculated on the basis of full quantum‐mechanical calculations. The obtained optimal factors are used in PDE calculations of various ground‐ and excited‐state properties of molecules embedded in solvents described as polarizable environments. © 2017 Wiley Periodicals, Inc.
Quality specifications of routine clinical chemistry methods based on sigma metrics in performance evaluation
Authors: Xia Jun , Chen Su‐feng , Xu Fei , Zhou Yong‐lie
Published: June 2017

Introduction

Sigma metrics were applied to evaluate the performance of 20 routine chemistry assays, and individual quality control criteria were established based on the sigma values of different assays.

Methods

Precisions were expressed as the average coefficient variations (CVs) of long‐term two‐level chemistry controls. The biases of the 20 assays were obtained from the results of trueness programs organized by National Center for Clinical Laboratories (NCCL, China) in 2016. Four different allowable total error (TEa) targets were chosen from biological variation (minimum, desirable, optimal), Clinical Laboratory Improvements Amendments (CLIA, US), Analytical Quality Specification for Routine Analytes in Clinical Chemistry (WS/T 403‐2012, China) and the National Cholesterol Education Program (NECP).

Results

The sigma values from different TEa targets varied. The TEa targets for ALT, AMY, Ca, CHOL, CK, Crea, GGT, K, LDH, Mg, Na, TG, TP, UA and Urea were chosen from WS/T 403‐2012; the targets for ALP, AST and GLU were chosen from CLIA; the target for K was chosen from desirable biological variation; and the targets for HDL and LDL were chosen from the NECP. Individual quality criteria were established based on different sigma values.

Conclusions

Sigma metrics are an optimal tool to evaluate the performance of different assays. An assay with a high value could use a simple internal quality control rule, while an assay with a low value should be monitored strictly.
Morphology of the tongue of Vermilingua (Xenarthra: Pilosa) and evolutionary considerations
Authors: Casali Daniel M. , Martins‐Santos Elisângela , Santos André L. Q. , Miranda Flávia R. , Mahecha Germán A. B. , Perini Fernando A.
Published: June 2017

The tongue of anteaters (Xenarthra, Pilosa, Vermilingua) is a highly specialized for myrmecophagy. Here, we describe the topography and histology of the tongue, and compare it to that of other xenarthrans and other myrmecophagous eutherian mammals. The tongue of Vermilingua is long and slender, with an apical protuberance, which differs between Myrmecophagidae and Cyclopes didactylus. In the former, the rostral region is conical, and in the latter, it is dorsoventrally compressed, as observed in sloths. The tongue of Vermilingua has filiform and circumvallate papillae on the surface; foliate and fungiform papillae are absent. The filiform papillae of Myrmecophaga tridactyla are simple all over the tongue, differing from Tamandua tetradactyla and Cyclopes didactylus, which present composed filiform papillae in the rostral and middle regions. Histologically, the tongue has a peculiar organization of muscular and neurovascular tissues, differing from the usual mammalian pattern. However, the tongue structure is less divergent in Cyclopes. The presence of two circumvallate papillae is common to the three major clades of Xenarthra (Cingulata, Folivora and Vermilingua). In each group, the tongue may reflect functional features related to myrmecophagous (anteaters and some armadillos), omnivorous (remaining armadillos) and folivorous (sloths) feeding habits. The similarities between the tongues of Vermiligua and other non‐xenarthran eutherian myrmecophagous mammals are somewhat general and, under close inspection, superficial, being an example of different lineages achieving the same morphofunctional adaptations through distinct evolutionary pathways.
Downscaling annual precipitation with TMPA and land surface characteristics in China
Authors: Ma Ziqiang , Zhou Yin , Hu Bifeng , Liang Zongzheng , Shi Zhou
Published: June 2017

Very high‐resolution (∼1 km) precipitation datasets are needed in various applications, especially in the hydrological, environmental, agricultural, and biological fields, although they also have major roles in the climate sciences. Nevertheless, various studies have concurred that the spatial distribution of precipitation is influenced by land surface characteristics through non‐stationary relationships, and that this characteristic is generally not considered fully by either global or local models using fixed combinations of variables (e.g. the normalized difference vegetation index and/or digital elevation models). This study introduced a new spatial downscaling algorithm, a divide‐and‐conquer method (called Cubist), to downscale Tropical Rainfall Measuring Mission (TRMM) satellite precipitation data over China from 2000 to 2015. In this endeavour, we considered the non‐stationary relationships between precipitation and land surface characteristics at various scales and derived the following conclusions: (1) The relationships and related variables explaining the spatial distribution of precipitation varied with spatial scale. (2) The Cubist algorithm achieved greater accuracy than Multivariate Linear Regression (MLR) models, and it was found to compensate for the disadvantages of MLR overestimation and underestimation at low and high values, respectively. (3) In downscaling, the monthly Version 7 TRMM Multisatellite Precipitation Analysis (TMPA) datasets over China, the entire study area was separated into subregions driven by spatial datasets according to geographic similarities, which were similar to Chinese rainfall zones.
Weather regimes associated with summer rainfall variability over southern Mexico
Authors: Díaz‐Esteban Yanet , Raga Graciela B.
Published: June 2017

This study focuses on the identification of weather regimes (WRs) over Mexico, the tropical eastern Pacific, Central America and the Caribbean, associated with seasonal precipitation over southern Mexico. A self‐organizing maps (SOM) analysis of sea level pressure, 850‐hPa horizontal winds and 925‐hPa‐specific humidity for the period 1997–2013 was carried out to identify the circulation patterns. This approach allowed the discrimination of wet and dry regimes, with clear and distinct features. Weather patterns exhibiting negative (positive) mean sea level pressure anomalies, southerly (northerly) winds, above‐ (below‐) average low‐level moisture and little (large) influence of the North Atlantic Subtropical High (NASH), resulted in above‐ (below‐) average precipitation over southern Mexico. The intra‐seasonal variability of the WRs and their associated rainfall is well captured by this methodology. In particular, the mid‐summer drought (MSD) during late July and early August, is clearly represented by a group of patterns, which evidence a strong influence of the NASH, strong easterly winds in the Caribbean Basin and reduced low‐level humidity, all factors that combine to induce below‐normal rainfall over southern Mexico. The analysis of the inter‐annual variability of the WRs suggests that year‐to‐year variations in their frequencies can impact summer rainfall in the regions of southern Mexico considered in this study. In particular, the analysis indicates that the dominant WR associated with the MSD exhibits a 3‐ to 4‐year modulation in its frequency of occurrence, which has not been previously reported in the literature. The main MSD pattern is more frequent during dry years and has a significant correlation with the Multivariate El Niño‐Southern Oscillation (ENSO) Index (MEI), indicating that MSD is stronger during ‘El Niño’ years. Also, WRs associated with negative (positive) rainfall anomalies showed positive (negative) correlations with the MEI, suggesting a possible modulation by ENSO phases.
Protective Factors, Coping Appraisals, and Social Barriers Predict Mental Health Following Community Violence: A Prospective Test of Social Cognitive Theory
Authors: Smith Andrew J. , Felix Erika D. , Benight Charles C. , Jones Russell T.
Published: June 2017

This study tested social cognitive theory of posttraumatic adaptation in the context of mass violence, hypothesizing that pre‐event protective factors (general self‐efficacy and perceived social support) would reduce posttraumatic stress symptoms (PTSS) and depression severity through boosting post‐event coping self‐efficacy appraisals (mediator). We qualified hypotheses by predicting that post‐event social support barriers would disrupt (moderate) the health‐promoting indirect effects of pre‐event protective factors. With a prospective longitudinal sample, we employed path models with bootstrapping resampling to test hypotheses. Participants included 70 university students (71.4% female; 40.0% White; 34.3% Asian; 14.3% Hispanic) enrolled during a mass violence event who completed surveys one year pre‐event and 5–6 months post‐event. Results revealed significant large effects in predicting coping self‐efficacy (mastery model, R2= .34; enabling model, R2= .36), PTSS (mastery model, R2= .35; enabling model, R2= .41), and depression severity (mastery model, R2= .43; enabling model, R2= .46). Overall findings supported study hypotheses, showing that at low levels of post‐event social support barriers, pre‐event protective factors reduced distress severity through boosting coping self‐efficacy. However, as post‐event social support barriers increased, the indirect, distress‐reducing effects of pre‐event protective factors were reduced to nonsignificance. Study implications focus on preventative and responsive intervention.
Land Degradation Controlled and Mitigated by Rubber‐based Agroforestry Systems through Optimizing Soil Physical Conditions and Water Supply Mechanisms: A Case Study in Xishuangbanna, China
Authors: Jiang Xiao Jin , Liu Wenjie , Wu Junen , Wang Pingyuan , Liu Changan , Yuan Zi‐Qiang
Published: June 2017

Different rubber‐based agroforestry systems are adopted to control and mitigate land degradation. However, the soil physical conditions and soil hydrological processes of different agroforestry systems are still unclear. Thus, in this study, rubber (Hevea brasiliensis) monoculture, rubber and Clerodendranthus spicatus agroforestry system (RCS) and rubber and Amomum villosum agroforestry system (RAV) were developed from a degraded land that had similar backgrounds of terrain and management measures for 50 years. Conventional methods were applied, and dye tracer experiments were conducted to measure the soil physical conditions and determine the water movement in soil. After 5 years' growth, both RCS and RAV could effectively promote the soil physical conditions and optimize soil structure by improving the proportion of the three soil phases. Favourable soil properties, multiple‐layered canopies and ground cover in agroforestry systems could promote the formation of three‐dimensional hydraulic redistribution in soil profile. The infiltration of rainfall into the soil was enhanced; meanwhile, surface runoff and soil erosion were mitigated, and then more water was transported, redistributed and stored into the different soil layers by the more dominant preferential flow, water exchange and lateral flow in soil profiles. These water supply mechanisms could allow planting intercrops with rubber trees to uptake water from different water sources and coexist in an agroforestry system. Our results highlighted that rubber‐based agroforestry systems are a useful management practice to maximize the utilization of land and water resources. Copyright © 2017 John Wiley & Sons, Ltd.
Light‐Switchable Azobenzene‐Containing Macromolecules: From UV to Near Infrared
Authors: Weis Philipp , Wu Si
Published: June 2017

Azobenzene‐containing macromolecules (azo‐macromolecules) such as azobenzene‐containing polymers (azopolymers) and azobenzene‐functionalized biomacromolecules are photoswitchable macromolecules. Trans‐to‐cis photoisomerization in conventional azo‐macromolecules is induced by ultraviolet (UV) light. However, UV light cannot penetrate deeply into issue and has a very small fraction in sunlight. Therefore, conventional azo‐macromolecules are problematic for biomedical and solar‐energy‐related applications. In this Feature Article, the strategies for constructing visible and near‐infrared (NIR) light‐responsive azo‐macromolecules are reviewed, and the potential applications of visible‐ and NIR‐light‐responsive azo‐macromolecules in biomedicine and solar energy conversion are highlighted. The remaining challenges in the field of photoswitchable azo‐macromolecules are discussed.
Mechanical and Thermo‐Mechanical Properties of Discontinuously and Continuously Processed Biogenic Wood‐Plastic Composites from Polyamide 11 and Chemically Modified Beech Particles
Authors: Zierdt Patrick , Kulkarni Gaurav , Theumer Torsten
Published: June 2017

The resulting mechanical and thermo‐mechanical properties of discontinuously and continuously processed biogenic wood‐plastic composites (bio‐WPC) from polyamide 11 and chemically modified beech particles are investigated. It is found that continuous processing with a twin‐screw extruder (TSE) and subsequent industrial scale injection molding leads to a lower elastic modulus, an equal tensile strength, a higher strain at break and a lower glass transition temperature as compared to discontinuous processing with an internal mixer (IM) and subsequent laboratory scale injection molding. This is attributed to a more distinctive beech particle size reduction and shear stress induced chain scission during TSE processing and subsequent injection molding.
Prediction of Crack Toughness of Rubber Under Impact Loading Conditions
Authors: Lach Ralf , Reincke Katrin , Grellmann Wolfgang
Published: June 2017

Sulphur‐crosslinked styrene–butadiene vulcanizate filled with carbon black up to 50 parts per hundred rubber (phr) were mainly investigating using an instrumented impact tensile tester. The experimentally determined and the calculated critical J‐values are in a good agreement. The pronounced energy dissipation capability of the vulcanizate with 50 phr carbon black does not take effect because the existence of a large number of agglomerates seen by using of a transmission electron microscope at reaching the percolation threshold leads to a more brittle behaviour.
Assessment of Fracture Behavior Under Impact Loading with Simultaneous Recording of Acoustic Emission
Authors: Schoßig Marcus , Bierögel Christian , Grellmann Wolfgang
Published: June 2017

For the assessment of the damage kinetics during the instrumented Charpy impact test (ICIT), the acoustic emissions (AEs) were recorded and the transient signal of the acoustic sensor was analyzed with the wavelet transform (WT). Based on the results discussed in this paper, an assessment of the resistance against stable crack initiation of glass fiber reinforced materials with the help of AE measurements under impact conditions is possible.
Comparing Mechanical Tests of Carbon Fiber Epoxy Resin and Carbon Fiber Polyamide Resin Composites
Authors: Schreiber Robert , Klepek Manuel , Moneke Martin , Fleischhauer Martin
Published: June 2017

The mechanical parameters of UD carbon fibre with polyamide and epoxy matrix using perpendicular tension and shear tests according to ASTM 7078 are compared. The polyamide matrix has been polymerized form ϵ‐caprolactam, therefore, specimen have a good fibre matrix adhesion but still sometimes suffer from inhomogen impregnation. This effect results in a higher standard deviation for PA specimen. Furthermore the specimen from polyamide have higher strain at break and stress at break. Epoxy specimen have a higher young's modulus and shear modulus.
Time‐Lapsing Evaluation of the Retardation Behaviour of Polypropylene Homo‐ and Copolymers using the Stepped Isothermal Method based on Depth‐Sensing Macroindentation
Authors: Krolopp Tobias , Lach Ralf , Schöne Jan , Mecklenburg Thomas , Langer Beate , Grellmann Wolfgang
Published: June 2017

The Stepped Isothermal Method (SIM) is a relatively new method for accelerated determination of the creep behaviour of polymers. The need for such a new method arises from the fact that for modern plastic components such as pipe systems minimum lifetimes of 50 years and more are achieved. The analysis of creep applying conventional methods of testing over such long periods of time is not reasonable from an economic point of view. This forms the basis for the development of accelerated procedures such as SIM. Plastic components can exhibit creep characteristics to be a function of the position due to processing. Such position‐dependent creep behaviour cannot be imaged by volume‐sensitive creep tests such as SIM under uniaxial tensile load. Therefore, SIM was implemented by means of recording macroindentation to characterize the local long‐time creep behaviour and the expressiveness of this method for different polypropylene materials was shown in this study.
Influence of Ageing on Sealability of Elastomeric O‐Rings
Authors: Kömmling Anja , Jaunich Matthias , Pourmand Payam , Wolff Dietmar , Gedde Ulf W.
Published: June 2017

At BAM, which is the federal institute for materials research and testing in Germany, it is one of our tasks to evaluate the safety of casks designed for transport and/or storage of radioactive material. This includes the assessment of the service lifetime of elastomeric seals that are part of the container lid system with regard to the requirements for long‐term safety (40 years and more) of the containers. Therefore, we started an accelerated ageing programme with selected rubbers often used for seals (HNBR, EPDM and FKM) which are aged at four different temperatures (75 °C, 100 °C, 125 °C and 150 °C) up to 1.5 years. In order to assess sealability, O‐rings are aged in compression by 25% (corresponding to the compression during service) between plates as well as in flanges that allow leakage rate measurements. For comparison, uncompressed O‐rings are aged as well. Further methods characterising seal performance are compression stress relaxation (CSR) reflecting the loss of sealing force of a compressed seal over time, and compression set (CS) which represents the recovery behaviour of a seal after release from compression. Additionally, hardness is measured for information about the change of mechanical properties. The experimental results indicate that while hardness, CSR and CS show considerable degradation effects, the leakage rate stays relatively constant or even decreases until shrinkage combined with the loss of resilience of the aged seal leads to leakage. This demonstrates that static leakage rate, which is the only available direct seal performance criterion, has only limited sensitivity towards the degradation of the seal material. CS data is extrapolated using time‐temperature shifts and Arrhenius graphs. An exemplary CS of 50% would be reached after approx. 1.2, 17 and 29 years at 60 °C for HNBR, EPDM and FKM respectively.
Three‐Phase Model of Two‐Component Blends Consisting of a Polystyrene–Polybutadiene Star Block Copolymer and a Polystyrene Homopolymer
Authors: Lach Ralf , Satapathy Bhabani K. , Weidisch Roland , Grellmann Wolfgang , Knoll Konrad
Published: June 2017

Based on results of atomic force microscopy and dynamic mechanical analysis applied on binary blends of polystyrene (PS)–poly­butadiene (PB) star block copolymers (ST3) having different compositions, a three‐phase morphology that comprises PB‐rich, PS/PB‐mixed and PS‐rich phase has been found. The pronounced enhancement of toughness in blends with 20–30 wt.‐% PS homopolymer compared to pure ST3 can be understood by improvement of the stress transfer between the microdomains through the additional hPS‐induced interfacial PS/PB‐mixed volume fraction and the co‐continuous morphology.
Multiecho pseudo‐golden angle stack of stars thermometry with high spatial and temporal resolution using k‐space weighted image contrast
Authors: Svedin Bryant T. , Payne Allison , Bolster Bradley D. , Parker Dennis L.
Published: June 2017

Purpose

Implement and evaluate a 3D MRI method to measure temperature changes with high spatial and temporal resolution and large field of view.

Methods

A multiecho pseudo‐golden angle stack‐of‐stars (SOS) sequence with k‐space weighted image contrast (KWIC) reconstruction was implemented to simultaneously measure multiple quantities, including temperature, initial signal magnitude M(0), transverse relaxation time (
), and water/fat images. Respiration artifacts were corrected using self‐navigation. KWIC artifacts were removed using a multi‐baseline library. The phases of the multiple echo images were combined to improve proton resonance frequency precision. Temperature precision was tested through in vivo breast imaging (N = 5 healthy volunteers) using both coronal and sagittal orientations and with focused ultrasound (FUS) heating in a pork phantom using a breast specific MR‐guided FUS system.

Results

Temperature measurement precision was significantly improved after echo combination when compared with the no echo combination case (spatial average of the standard deviation through time of 0.3–1.0 and 0.7–1.9°C, respectively). Temperature measurement accuracy during heating was comparable to a 3D seg‐EPI sequence. M(0) and
values showed temperature dependence during heating in pork adipose tissue.

Conclusion

A self‐navigated 3D multiecho SOS sequence with dynamic KWIC reconstruction is a promising thermometry method that provides multiple temperature sensitive quantitative values. Magn Reson Med 79:1407–1419, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
An open 8‐channel parallel transmission coil for static and dynamic 7T MRI of the knee and ankle joints at multiple postures
Authors: Jin Jin , Weber Ewald , Destruel Aurelien , O’Brien Kieran , Henin Bassem , Engstrom Craig , Crozier Stuart
Published: June 2017

Purpose

We present the initial in vivo imaging results of an open architecture eight‐channel parallel transmission (pTx) transceive radiofrequency (RF) coil array that was designed and constructed for static and dynamic 7T MRI of the knee and ankle joints.

Methods

The pTx coil has a U‐shaped dual‐row configuration (200 mm overall length longitudinally) that allows static and dynamic imaging of the knee and ankle joints at various postures and during active movements. This coil structure, in combination with B1 shimming, allows flexible configuration of B1 transmit profiles, with good homogeneity over 120‐mm regions of interest. This coil enabled high‐resolution gradient echo (e.g., 3D dual‐echo steady state [DESS] and 3D multiecho data image combination [MEDIC]) and turbo spin echo (TSE) imaging (e.g., with proton density weighting [PDw], PDw with fat saturation, and T1 and T2 weightings) with local RF energy absorption rates well below regulatory limits.

Results

High‐resolution 2D and 3D image series (e.g., 0.3 mm in‐plane resolution for TSE, 0.47 mm isotropic for DESS and MEDIC) were obtained from the knee and ankle joints with excellent tissue contrast. Dynamic imaging during continuous knee and ankle flexion‐extension cycles were successfully acquired.

Conclusion

The new open pTx coil array provides versatility for high‐quality static and dynamic MRI of the knee and ankle joints at 7T. Magn Reson Med 79:1804–1816, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
A relationship between tensile strength and loading stress governing the onset of mode I crack propagation obtained via numerical investigations using a bonded particle model
Authors: Han Zhenyu , Weatherley Dion , Puscasu Ruslan
Published: June 2017

Numerical models based on the discrete element method are used to study the fracturing process in brittle rock‐like materials under direct and indirect tension. The results demonstrate the capacity of the model to capture the essential characteristics of fracture including the onset of crack propagation, stable and unstable crack growth, arrest and reinitiation of fracturing, and crack branching. Simulations of Brazilian indirect tension tests serve to calibrate the numerical model, relating macroscopic tensile strength of specimens to their micromechanical breakage parameters. A second suite of simulations reveals a linear relationship between the tensile strength of specimens and the loading stress for which mode I tensile crack propagation ensues. Based on these results, a crack initiation criterion for brittle materials is proposed, prescribing the stressing conditions required to induce tensile failure. Such a criterion, if broadly applicable, provides a practical means to rapidly assess the failure potential of brittle materials under tensile loads.
Role of graphene oxide surface chemistry on the improvement of the interlaminar mechanical properties of resin infusion processed epoxy‐carbon fiber composites
Authors: Ramos‐Fernandez Gloria , Muñoz María , García‐Quesada Juan C. , Rodriguez‐Pastor Iluminada , Martin‐Gullon Ignacio
Published: June 2017

The present study deals with the influence of graphene oxide functional groups on their ability to reinforce an epoxy resin when forming carbon fiber composites. Composites were processed through the direct vacuum infusion of the doped resin into carbon fiber fabrics. We used graphene oxide nanosheets with two different chemical characters: as‐produced graphene oxide, with a high oxygen content and acid character, and a simple ammonia base‐washed graphene oxide, which to a great extent removes the oxidative debris or highly oxidized fulvic‐like entities, resulting in an average lower oxygen content and cleaner surface sheets than as‐produced graphene oxide. Base‐washed graphene oxide performed considerably better in both tensile and mode‐I interlaminar properties of carbon fiber composites. The fracture energy required for the onset of mode I interlaminar fracture toughness was enhanced 31% when using as‐produced graphene oxide and 60% when using base‐washed graphene oxide by adding 0.2 wt% only. More interestingly, base‐washed graphene oxide produces a higher delamination resistance along the entire range of crack growth. The effect of adding graphene oxide with a cleaner surface and lower oxygen surface chemistry allows direct chemical bonding matrix‐graphene when the resin is curing, promoting a better interface fiber‐resin and consequently, improving the reinforcement efficiency. POLYM. COMPOS., 39:E2116–E2124, 2018. © 2017 Society of Plastics Engineers
Qualitative Analysis of Polyphenols in Macroporous Resin Pretreated Pomegranate Husk Extract by HPLC‐QTOF‐MS
Authors: Abdulla Rahima , Mansur Sanawar , Lai Haizhong , Ubul Ablikim , Sun Guangying , Huang Guozheng , Aisa Haji Akber
Published: June 2017

Introduction

Pomegranate (Punica granatum L.) husk is a traditional herbal medicine abundant in phenolic compounds and plays some roles in the treatment of oxidative stress, bacterial and viral infection, diabetes mellitus, and acute and chronic inflammation.

Objective

Identification and determination of polyphenols in macroporous resin pretreated pomegranate husk extract by high performance liquid chromatography coupled with quadrupole time‐of‐flight tandem mass spectrometry (HPLC‐QTOF‐MS).

Methods

The total polyphenols of pomegranate husk were prepared by ethanol extraction followed by pretreatment with HPD‐300 macroporous resin. The polyphenolic compounds were qualitatively analysed by HPLC‐QTOF‐MS in negative electrospray ionisation (ESI) mode at different collision energy (CE) values.

Results

A total of 50 polyphenols were detected in the extract of pomegranate husk, including 35 hydrolysable tannins and 15 flavonoids with distinct retention time, fragmentation behaviours and characteristics, and the accurate mass‐to‐charge ratios at low, moderate and high CE values. Of these, we identified nine compounds for the first time in the pomegranate husk, including hexahydroxydiphenoyl‐valoneoyl‐glucoside (HHDP‐valoneyl‐glucoside), galloyl‐O‐punicalin, rutin, hyperoside, quercimeritrin, kaempferol‐7‐O‐rhahmano‐glucoside, luteolin‐3′‐O‐arabinoside, luteolin‐3′‐O‐glucoside, and luteolin‐4′‐O‐glucoside. To validate the specificity and accuracy of mass spectrometry in the detection of polyphenols, as compared to the fragmentation pathways of granatin B in detail, including the HHDP‐valoneyl‐ glucoside was first identified from pomegranate husk.

Conclusion

The study provides evidence for the quality control and development of novel drugs based on polyphenols from the pomegranate husk. Copyright © 2017 John Wiley & Sons, Ltd.
A study of ADMET polyethylene with 21‐carbon branches on every 15th compared to every 19th carbon: What a difference four extra backbone methylenes make
Authors: Matsui Kazuya , Li Hong , Nozue Yoshinobu , Rojas Giovanni , Bell Michael , Shinohara Yuya , Amemiya Yoshiyuki , Wagener Kenneth B.
Published: June 2017

Precision polyethylenes with 21‐carbon alkyl branches precisely spaced on every either 15th or 19th carbon along the polymer backbone lead to the formation of two kinds of lamellae, yielding different thicknesses during the crystallization process. Thinner lamellae originate from side‐chain crystallization, whereas thicker lamellae are formed by cocrystallization of the branch and the main chain. Side‐chain crystallization (separate from main chain crystallization) is favored when the branch is placed on every 15th carbon. Cocrystallization (side chain with main chain) is favored with the branch on every 19th carbon. Both form stable hexagonal crystal units. A branch spacing separation of just four carbons along the main chain makes a remarkable difference in crystallization behavior. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 3090–3096
Gibberellic and kaurenoic hybrid strigolactone mimics for seed germination of parasitic weeds
Authors: Pereira Rondinelle G , Cala Antonio , Fernández‐Aparicio Mónica , Molinillo José MG , Boaventura Maria AD , Macías Francisco A
Published: June 2017

BACKGROUND

Parasitic weeds are widespread and cause significant losses in important crops. Their germination requires the detection of crop‐derived molecules such as strigolactones. Strigolactone mimics are germination‐inducing molecules with the potential to apply a suicidal germination strategy for seed bank control of parasitic weeds.

RESULTS

The D‐ring, which is instrumental in the germination process of seeds of parasitic weeds, was attached to gibberellin (GA3) and kaurenoic acid as the scaffold. It was shown that indeed strigolactone mimics prepared from GA3 and kaurenoic acid are active as stimulants when a D‐ring is present; some of the mimics are as active as GR24.

CONCLUSIONS

The starting molecules were plant hormones that had previous growth‐regulating activity in other organisms and the products showed enhanced activity towards parasitic weeds. The information generated may contribute to a better understanding of the germination biochemistry of the weed species used. Further research is required in this area but it is clear that the results are promising. © 2017 Society of Chemical Industry
The history and current status of glyphosate
Authors: Duke Stephen O
Published: June 2017

Glyphosate is the only herbicide to target the enzyme 5‐enolpyruvyl‐3‐shikimate phosphate synthase (EPSPS). It is a high use rate, non‐selective herbicide that translocates primarily to metabolic sinks, killing meristematic tissues away from the application site. Its phloem‐mobile properties and slow action in killing weeds allow the herbicide to move throughout the plant to kill all meristems, making it effective for perennial weed control. Since commercialization in 1974, its use has grown to dominate the herbicide market. Much of its use is on transgenic, glyphosate‐resistant crops (GRCs), which have been the dominant transgenic crops worldwide. GRCs with glyphosate provided the most effective and inexpensive weed management technology in history for a decade or more. However, as a consequence of the rapid increase in glyphosate‐resistant (GR) weeds, the effectiveness of glyphosate use in GRCs is declining. Critics have claimed that glyphosate‐treated GRCs have altered mineral nutrition and increased susceptibility to plant pathogens because of glyphosate's ability to chelate divalent metal cations, but the complete resistance of GRCs to glyphosate indicates that chelating metal cations do not contribute to the herbicidal activity or significantly affect mineral nutrition. The rates of increases in yields of maize, soybean, and cotton in the USA have been unchanged after high adoption rates of GRCs. Glyphosate is toxic to some plant pathogens, and thereby can act as a fungicide in GRCs. Ultra‐low doses of glyphosate stimulate plant growth in glyphosate‐susceptible plants by unknown mechanisms. Despite rapid and widespread increases in GR weeds, glyphosate use has not decreased. However, as GR weeds increase, adoption of alternative technologies will eventually lead to decreased use. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.
Virucides in apiculture: persistence of surrogate enterovirus under simulated field conditions
Authors: Prodělalová Jana , Malenovská Hana , Moutelíková Romana , Titěra Dalibor
Published: June 2017

BACKGROUND

Honeybee viruses have been recognized as being among the most important factors leading to colony losses worldwide. Colony food and faeces are regarded as possible sources of infectious viruses able to contaminate the environment and equipment of apiaries. Thus, methods for elimination of viruses are required. No cell culture assay for testing the effect of disinfectants on honeybee viruses is yet available. Therefore, surrogate virus was employed for testing of the efficacy of iodophor‐ and peracetic acid‐based disinfectants in combination with six organic contaminants at +6 °C and +22 °C. Moreover, we evaluated the persistence of the surrogate in honey at +6 °C, +22 °C, and +50 °C.

RESULTS

Iodophor‐based disinfectant showed a maximum reduction of virus titre of 3.4 log10. Peracetic acid reduced the titre (≥4 log10) only at 22 °C and without yeast extract/bovine serum albumin. After 25 days of incubation of the virus − honey mix, no decrease of virus titre was observed at +6 °C, whereas a significant reduction (3.5 log10) was found at +50 °C already after 1 day.

CONCLUSIONS

Both tested disinfectants can serve as appropriate virucides in apiaries. The effect of peracetic acid significantly depended on temperature and organic contaminants. The iodophor‐based disinfectant showed a stable antiviral effect at different temperatures and with different contaminants. © 2017 Society of Chemical Industry
Decision making in health care using robust parameter design with conditions‐based selection of regression estimators
Authors: Pegues Kathryn K. , Boylan Gregory L. , Cho Byung Rae
Published: June 2017

Health care professionals often use regression methods to quantitatively describe the functional relationships between predictors and outcomes. However, little research investigates the appropriateness of tool application for response‐surface‐based design of experiments, the choice of regression estimators under different environments, and the impact of the determination of optimum conditions, or optimal factor‐level settings, to achieve desirable target outcomes. Robust parameter design (RPD) is an established methodology for determining optimum conditions for a process to achieve specified process targets while minimizing variability of the outcomes. Underlying assumptions for RPD modeling and process conditions should be taken into account when selecting a regression estimator for developing fitted models. If these assumptions are incorrect, then a direct use of estimates obtained has the potential to be problematic, and the results may be potentially catastrophic, particularly when applied to the health care field. Many approaches to RPD in existing literature use ordinary least squares to obtain response functions by assuming normality and moderate variability in the underlying process. Given that some biologic processes are often highly variable and inherently asymmetric, a conditions‐based approach for the selection of a regression estimate technique needs to be explored. This paper examines alternative approaches to regression estimation when the process data indicates that asymmetry or a high degree of process variability exists. The performance of select alternative regression methods is compared using Monte Carlo simulation and numerical analysis.
Design and Synthesis of Iron‐Doped Nanostructured TiO2 and Its Potential Use in the Photodegration of Hazardous Materials Present in Personal Care Products
Authors: Bonfrate Valentina , Manno Daniela , Buccolieri Alessandro , Padmanabhan Sanosh K. , Licciulli Antonio , Serra Antonio , Braione Eugenia , Calcagnile Lucio , Giancane Gabriele
Published: June 2017

Parabens and phenoxyethanol are chemical compounds widely used as preservatives and antimicrobial agents in cosmetic and personal care products. The issue of their effect on human and environmental health is a particularly topical and relevant one that many national and international agencies reported about the risk from the use of such compounds. In the present paper, iron doped TiO2 nanoparticles were synthetized and characterized by morphological and spectroscopic techniques. The proposed synthesis was designed to improve the photocatalytic activity of the nanostructures towards the two preservatives compounds when irradiated by a visible light, in order to optimize the effect of natural irradiation on the photodegradation of the two compounds. Preliminary photocatalytic tests showed that the analytes’ concentration in water solutions under illumination in presence of both iron‐doped TiO2 and pure TiO2 decreased. A sensible enhancement of photocatalysis of both propylparaben and phenoxyethanol was recorded in presence of the Fe‐doped nanostructures as a consequence of the physical and chemical properties of the catalyst.