bluuebunny/crossref_metadata_2025 huggingface dataset:
Growth differentiation factor 15 is associated with left atrial/left atrial appendage thrombus in patients with nonvalvular atrial fibrillation
Authors: Hu Xiao Feng , Zhan Rui , Xu Shanhu , Wang Junjun , Wu Jiong , Liu Xiaoli , Li Yaguo , Chen Linhui
Published: January 2018

Background

There is evidence suggesting that growth differentiation factor 15 (GDF‐15) appears to be associated with stroke in patients with atrial fibrillation (AF). AF‐related thromboembolic stroke is predominantly attributed to the thrombus from the left atrium (LA) or left atrial appendage (LAA).

Hypothesis

GDF‐15 is related to LA/LAA thrombus in nonvalvular AF (NVAF) patients.

Methods

A total of 894 patients with NVAF without anticoagulation therapy were included in this study. All patients routinely underwent transesophageal echocardiography for detection of LA/LAA thrombus. GDF‐15 was measured by enzyme‐linked immunosorbent assay. Logistic regression models were used to test for association.

Results

LA/LAA thrombus was detected by transesophageal echocardiography in 69 (7.72%) patients with AF. The GDF‐15 levels in the patients with LA/LAA thrombus were significantly higher than those without LA/LAA thrombus (log10 GDF‐15: 2.989 ± 0.023 ng/L vs 2.831 ± 0.007 ng/L; P < 0.001). Logistic regression analysis showed that GDF‐15 was an independent risk factor for LA/LAA thrombus (odds ratio [per quarter]: 1.799, 95% confidence interval: 1.381‐2.344, P < 0.001) after adjusting for potential clinical risk factors. The optimal cutoff point for GDF‐15 predicting LA/LAA thrombus was 809.9 ng/L (sensitivity, 75.3%; specificity, 61.5%), determined by ROC curve. The area under the curve was 0.709 (95% confidence interval: 0.644‐0.770, P < 0.001).

Conclusions

Elevated GDF‐15 indicated a significantly increased risk for LA/LAA thrombus in NVAF patients. Thus, GDF‐15 might be a potentially useful adjunct in discriminating LA/LAA thrombus in NVAF patients.
Long‐term impacts of hemodialysis on the right ventricle: Assessment via 3‐dimensional speckle‐tracking echocardiography
Authors: Sun Minmin , Cao Xuesen , Guo Yao , Tan Xiao , Dong Lili , Pan Cuizhen , Shu Xianhong
Published: January 2018

Background

Right ventricular (RV) dysfunction is a major cause of death in patients undergoing maintenance hemodialysis (MHD). We used 3‐dimensional speckle‐tracking echocardiography (3DSTE) to evaluate long‐term impacts of MHD on RV function.

Hypothesis

In this study, RV dysfunction in MHD patients will be revealed and studied in depth by 3DSTE.

Methods

Echocardiography was performed on 110 consecutively enrolled individuals: 30 controls and 80 patients with MHD. Conventional echocardiographic parameters and 3DSTE parameters were obtained and compared between groups. Univariate and multivariate logistic regression analysis identified independent predictors of intradialytic hypotension (IDH).

Results

Compared with the control group, RV end‐diastolic volume (RVEDV) was markedly enlarged (46.1 ± 11.8 mL/m2 vs 42.3 ± 8.6 mL/m2; P = 0.047), whereas RV ejection fraction (RVEF) was significantly lower in the MHD group (50.6% ± 5.8% vs 55.2% ± 3.7%; P < 0.001). RV global, septal, and lateral wall longitudinal strains were also decreased in the MHD group (−18.2 ± 3.6 vs −22.6 ± 4.3%; −13.1 ± 3.8 vs −17.5 ± 5.5%; and −23.4 ± 4.7 vs −27.7 ± 4.0%, respectively; all P < 0.001). RVEF (odds ratio [OR]: 0.72, 95% confidence interval [CI]: 0.51 to 1.01, P = 0.038) and history of diabetes (OR: 11.14, 95% CI: 1.16 to 106.71, P = 0.036) were 2 independent predictors of IDH. Ultrafiltration rate was an independent factor associated with RVEF (β = −0.01, 95% CI: −0.019 to 0.001, P = 0.039).

Conclusions

RVEF by 3DSTE could be an important predictor of IDH in MHD patients, and lower ultrafiltration rate was protective for RVEF. 3DSTE may have potential in RV evaluation and risk stratification in MHD patients.
Cooperative and out‐of‐core execution of the irregular wavefront propagation pattern on hybrid machines with Intel® Xeon Phi™
Authors: Gomes Jeremias , de Melo Alba C. M. A. , Kong Jun , Kurc Tahsin , Saltz Joel H. , Teodoro George
Published: January 2018

The Irregular Wavefront Propagation Pattern (IWPP) is a core computing structure in several image analysis operations. Efficient implementation of IWPP on the Intel Xeon Phi is difficult because of the irregular data access and computation characteristics. The traditional IWPP algorithm relies on atomic instructions, which are not available in the SIMD set of the Intel Phi. To overcome this limitation, we have proposed a new IWPP algorithm that can take advantage of non‐atomic SIMD instructions supported on the Intel Xeon Phi. We have also developed and evaluated methods to use CPU and Intel Phi cooperatively for parallel execution of the IWPP algorithms. Our new cooperative IWPP version is also able to handle large out‐of‐core images that would not fit into the memory of the accelerator. The new IWPP algorithm is used to implement the Morphological Reconstruction and Fill Holes operations, which are operations commonly found in image analysis applications. The vectorization implemented with the new IWPP has attained improvements of up to about 5× on top of the original IWPP and significant gains as compared to state‐of‐the‐art the CPU and GPU versions. The new version running on an Intel Phi is 6.21× and 3.14× faster than running on a 16‐core CPU and on a GPU, respectively. Finally, the cooperative execution using two Intel Phi devices and a multi‐core CPU has reached performance gains of 2.14× as compared to the execution using a single Intel Xeon Phi.
A case series of Acceptance and Commitment Therapy (ACT) for reducing symptom interference in functional neurological disorders
Authors: Graham Christopher D. , O'Hara Daniel J. , Kemp Steven
Published: January 2018

There is limited high‐quality evidence supporting psychological treatments for functional neurological disorders (FNDs), and what evidence exists suggests that the impact of such treatments could be improved. One way to increase effectiveness is to utilize approaches that can have impact across heterogeneous FND presentations. Acceptance and Commitment Therapy (ACT) targets a transdiagnostic process called psychological flexibility and is used effectively to integrate multidisciplinary treatments in other clinical contexts. Here, we present a consecutive case series (N = 8) of a relatively brief (6 to 10 sessions) ACT intervention, delivered face to face by a clinical psychologist in an outpatient neuropsychology service. Treatment aimed to reduce symptom interference and improve mood via improvements in psychological flexibility. Service users presented with a range of FND symptoms (e.g., syncope, limb paralysis, and paraesthesia). Following treatment, 5 participants showed reliable improvements in symptom interference (Work and Social Adjustment Scale), 2 to the extent of clinical significance; 4 had reliable improvements in mood (Clinical Outcomes in Routine Evaluation—10), and 2 within the range of clinical significance. There were no reliable deteriorations in symptom interference or mood. Marked variation was apparent on the measure of psychological flexibility (Acceptance and Action Questionnaire II), with 4 reliable improvements, 3 within the range of clinical significance, and also 2 reliable deteriorations. These promising results suggest that further investigation of an ACT approach to FND is warranted. Future studies should include measures of psychological flexibility with greater comprehensibility.
Hidden in plain view: The impact of mediation on the mediator and implications for conflict resolution education
Authors: Malizia Deborah A. , Jameson Jessica Katz
Published: January 2018

Empirical evidence shows that middle and high school students trained to be peer mediators experience improved communication skills, increased empathy, enhanced self‐esteem, and improved academic performance. Yet scholars have not examined whether these benefits extend to mediators in other contexts. This article presents empirical evidence and theoretical support for the inference that mediation training and practice have a positive impact on the emotional well‐being of the mediator. Given the documented increase of mental health challenges in today's society, this largely untapped potential of mediation to improve the well‐being of the mediator has significant implications for conflict resolution education.
The Context in Mining Projects Influences the Corporate Social Responsibility Strategy to Earn a Social Licence to Operate: A Case Study in Peru
Authors: Saenz Cesar
Published: January 2018

The purpose of this paper is to understand how the context in mining projects influences the corporate social responsibility (CSR) strategy to earn a social licence to operate (SLO). This paper also presents a comparative case study analysis of four mining operations in Peru. This analysis was qualitative in nature and is complemented with insights from supplementary key informant interviews and the emerging literature on SLO and CSR. The findings show that mining projects with a complex‐unstable context take considerable effort and a longer process to earn an SLO. In this situation, it is not recommended that companies use either a defensive strategy or compliance. Instead, the company must use strategic and managerial strategies to reduce social conflicts. Also, when the context is low or of moderate uncertainty, it is preferable to use strategic and managerial strategies in order to gain an SLO. Copyright © 2018 John Wiley & Sons, Ltd and ERP Environment
A novel active‐clamp zero‐voltage‐switching buck‐boost converter
Authors: Hieu Pham Phu , Hsieh Yao‐Ching , Lin Jing‐Yuan , Huang Bing‐Siang , Chiu Huang‐Jen
Published: January 2018

An active‐clamp zero‐voltage‐switching (ZVS) buck‐boost converter is proposed in this paper to improve the performance of converter in light load condition. By employing a small resonant inductor, the ZVS range of switches could be adjusted to very light load condition. Moreover, 2 clamping capacitors are added in the converter to eliminate the voltage spike on the switches during transition. The operating principle of the proposed converter is analyzed, and the optimal design guide for full range ZVS is also provided. A 60‐W output prototype is experimentally built and tested in laboratory to verify the feasibility of proposed converter. The measured results show the critical ZVS operation of power switches at 1 and 0.7‐W output power for buck and boost mode, respectively. The peak conversion efficiency is up to 92.3%.
Magnetoencephalographic study of event‐related fields and cortical oscillatory changes during cutaneous warmth processing
Authors: An Kyung‐min , Lim Sanghyun , Lee Hyun Joon , Kwon Hyukchan , Kim Min‐Young , Gohel Bakul , Kim Ji‐Eun , Kim Kiwoong
Published: January 2018

Thermoreception is an important cutaneous sense, which plays a role in the maintenance of our body temperature and in the detection of potential noxious heat stimulation. In this study, we investigated event‐related fields (ERFs) and neural oscillatory activities, which were modulated by warmth stimulation. We developed a warmth stimulator that could elicit a warmth sensation, without pain or tactile sensation, by using a deep‐penetrating 980‐nm diode laser. The index finger of each participant (n = 24) was irradiated with the laser warmth stimulus, and the cortical responses were measured using magnetoencephalography (MEG). The ERFs and oscillatory responses had late latencies (∼1.3 s and 1.0–1.5 s for ERFs and oscillatory responses, respectively), which could be explained by a slow conduction velocity of warmth‐specific C‐fibers. Cortical sources of warmth‐related ERFs were seen in the bilateral primary and secondary somatosensory cortices (SI and SII), posterior part of the anterior cingulate cortex (pACC), ipsilateral primary motor, and premotor cortex. Thus, we suggested that SI, SII, and pACC play a role in processing the warmth sensation. Time–frequency analysis demonstrated the suppression of the alpha (8–13 Hz) and beta (18–23 Hz) band power in the bilateral sensorimotor cortex. We proposed that the suppressions in alpha and beta band power are involved in the automatic response to the input of warmth stimulation and sensorimotor interactions. The delta band power (1–4 Hz) increased in the frontal, temporal, and cingulate cortices. The power changes in delta band might be related with the attentional processes during the warmth stimulation.
Learning and memory performance following acute intranasal insulin administration in abstinent smokers
Authors: Hamidovic Ajna , Candelaria Lionel , Rodriguez Ihsan , Yamada Mikiko , Nawarskas James , Burge Mark R.
Published: January 2018

The highest incidence of relapse to smoking occurs within the first 2 weeks of a cessation attempt. In addition to enhanced nicotine craving, this phase of smoking cessation is also marked by learning and memory dysfunction. Many smokers are not able to overcome these symptoms, and they relapse to smoking shortly after trying to quit. In two clinical studies, we evaluated intranasal insulin for efficacy in improving learning and memory function during nicotine withdrawal. Our first study was a crossover evaluation (N = 19) following 20 hr of smoking abstinence. Study 2 was a parallel design study (N = 50) following 16 hr of abstinence. Intranasal insulin (60 IU) dose was administered in both studies and cognitive function was measured using California Verbal Learning Test‐II. Intranasal insulin did not improve learning over the 5 verbal learning trials. In addition, intranasal insulin did not improve either short‐ or long‐delay recall in either study. In summary, the one‐time administration of intranasal insulin does not improve verbal learning and memory in smokers. Whether longer administration schedules may be of benefit should be evaluated in future studies.
Long noncoding RNA NEAT1‐modulated miR‐506 regulates gastric cancer development through targeting STAT3
Authors: Tan Hai‐Yang , Wang Changcheng , Liu Gao , Zhou Xiang
Published: January 2018

Accumulating evidence has indicated that long noncoding RNA NEAT1 exerts critical roles in cancers. So far, the detailed biological role and mechanisms of NEAT1, which are responsible for human gastric cancer (GC), are still largely unknown. Here, we observed that NEAT1 and STAT3 expressions were significantly upregulated in human GC cells including BGC823, SGC‐7901, AGS, MGC803, and MKN28 cells compared with normal gastric epithelial cells GES‐1, while miR‐506 was downregulated. We inhibited NEAT1 and observed that NEAT1 inhibition was able to repress the growth, migration, and invasion of GC cells. Conversely, overexpression of NEAT1 exhibited an increased ability of GC progression in BGC823 and SGC‐7901 cells. Bioinformatics analysis, dual luciferase reporter assays, RIP assays, and RNA pull‐down tests validated the negative binding correlation between NEAT1 and miR‐506. In addition, it was found that miR‐506 can modulate the expression of NEAT1 in vitro. STAT3 was predicted as a messenger RNA (mRNA) target of miR‐506, and miR‐506 mimics can suppress STAT3 mRNA expression. Subsequently, it was observed that downregulation of NEAT1 can restrain GC development by decreasing STAT3, which can be reversed by miR‐506 inhibitors. Therefore, it was hypothesized in our study that NEAT1 can be recognized as a competing endogenous RNA to modulate STAT3 by sponging miR‐506 in GC. In conclusion, we implied that NEAT1 can serve as an important biomarker in GC diagnosis and treatment.
Early psychotherapeutic empathy, alliance, and client outcome: Preliminary evidence of indirect effects
Authors: McClintock Andrew S. , Anderson Timothy , Patterson Candace L , Wing Edgar H
Published: January 2018

The association between psychotherapeutic empathy and client outcome is well established, yet the mechanisms underlying this association remain poorly understood. We hypothesized that early experiences of empathy influence outcome through the working alliance. To test this hypothesis, we used archival data collected from 56 clients (mean [M] age = 19.5 years, 83.9% female, 76.8% White) who reported mild, moderate, or severe depressive symptoms at screening and pretreatment assessments and then received five sessions of evidence‐based psychotherapy. Therapists (M age = 26.0 years, 50% female, 100% White) were six students in a clinical psychology PhD program. Results of bootstrap analyses were consistent with the idea that early experiences of empathy strengthen the alliance (specifically the goals and tasks facets), which in turn facilitates improvements in depressive symptoms and psychological well‐being. While preliminary, these results implicate a specific pathway of change in the treatment of depression.
Operator training simulators for biorefineries: current position and future directions
Authors: Isimite Joseph , Baganz Frank , Hass Volker C
Published: January 2018

Recent technological advances in the development of alternative energy sources, including biofuels, for transportation and energy requirements have demonstrated the need for highly skilled engineers and operators in the biotechnological industries. Although operator training simulators (OTS) used in the traditional chemical process industries may be used to train biorefinery operators and engineers, several distinct aspects of bioprocess operations make their direct application limited. The development and deployment of OTSs for use in biotechnological processes is therefore beginning to gain increasing attention. This review paper examines the present status of OTS development and use in biorefineries, including future considerations on how an OTS may be used to improve operator competence, maximise biorefinery operational efficiencies and protect people and the environment.

The general premise of an OTS is that model‐based operator training simulators can be used to verifiably enhance the training of industrial operators to run complex biorefineries. Only a few examples of the design and application of OTSs in large‐scale biorefineries have so far been reported. A discussion of the mathematical models used for OTS development is briefly presented, as well as available OTS design frameworks and vendors, including their benefits and drawbacks. The review concludes by looking at possible future directions of OTS development and use in biorefineries and their contribution in facilitating the transition to a bio‐based economy. © 2018 Society of Chemical Industry
Orphanhood, Household Relationships, School Attendance and Child Labor in Zimbabwe
Authors: Novella Rafael
Published: January 2018

The high incidence of orphanhood among children makes Zimbabwe an interesting case to study the school/work decision for children able to attend lower secondary. After controlling for household wealth, covariates at the individual, and household levels, and community fixed effects, I find that orphans are less likely to attend school and more likely to work. While orphans and non‐orphans face the same marginal cost to go to school and work, living in blended households places orphans at a higher disadvantage. The main factor related to discrimination within households is living with household heads with whom children are not closely biologically related. Copyright © 2018 John Wiley & Sons, Ltd.
Dynamic capabilities’ functioning in a private equity‐backed firm
Authors: Ciao Biagio
Published: January 2018

Private equity acquisition is a source of dynamic capabilities that develop resources to both improve the target firm’s competitive advantage within the original business and create economic growth, even though they could generate more value by promoting new businesses. Private equity‐backed firms adopt a focused strategy because dynamic capabilities work to generate competitive advantages in the existing businesses, feed exploitation rather than exploration, and focus on original value chain activities without integration processes. The target firm adopts responsible behavior because it is oriented to economic growth; thereby the worries about private equity‐backing can be mitigated. Future quantitative works could test the results of this article on a larger sample and in industries where the economic growth is insufficient to define responsible social behavior involving crucial social needs such as health care.
The application of digestive tract lactic acid bacteria with high esterase activity for zearalenone detoxification
Authors: Chen Shiau‐Wei , Hsu Jih‐Tay , Chou Yan‐An , Wang Han‐Tsung
Published: January 2018

BACKGROUND

Zearalenone (ZEA) is an estrogenic mycotoxin produced by several Fusarium species and frequently contaminates cereals used for food or animal feed. This study attempted to select lactic acid bacteria (LAB) with high esterase activity from the digestive tract, with the goal of using these bacteria for ZEA detoxification.

RESULTS

No ZEA activity‐related biotransformation products were observed in three isolates (B1, B2 and D10) during incubation in the presence of ZEA. All three LAB strains were Lactobacillus plantarum, but the API 50 CHL results suggested that the three isolates were different strains. Increased esterase activity was associated with an increase in cell growth, and the ZEA‐detoxifying capabilities of isolates rely on the concentration of bacteria in the culture medium. The lipolytic activity and ZEA removal assay indicated that ZEA degradation by the supernatant fraction was dependent on esterase activity; the supernatant of B2 strain showed the highest ZEA degradation ability and did not release the binding ZEA back into the medium. The D10 strain showed fast ZEA binding ability during the late log phase but began to release the bound ZEA back into the medium after the early stationary phase. All isolates showed good acid and bile salt tolerance ability but all strains showed low adhesion ability to epithelial cells.

CONCLUSION

Based on the ZEA removal characterization and ability of the isolates, it is suggested that the isolates could be applied to ZEA detoxification of contaminated feed, but the with the requirement of high cell number for ZEA binding and limited degradation time before absorption of ZEA in the digestive tract. © 2018 Society of Chemical Industry
Selection of Leuconostoc strains isolated from artisanal Serrano Catarinense cheese for use as adjuncts in cheese manufacture
Authors: Seixas Felipe Nael , Rios Edson Antônio , Martinez de Oliveira André Luiz , Beloti Vanerli , Poveda Justa Maria
Published: January 2018

BACKGROUND

Serrano Catarinense cheese is a raw bovine milk cheese produced in the region of Santa Catarina, Brazil. Twelve representative strains of Leuconostoc isolated from 20 samples of this artisanal cheese were selected and submitted for evaluation of the acidifying, proteolytic, autolytic, aminopeptidase and lipolytic activities, NaCl and acid resistance, production of dextran and biogenic amines and antimicrobial activity. The aim was to genetically and technologically characterize the Leuconostoc strains in order to use them in mixed starter cultures for cheese manufacture.

RESULTS

Leuconostoc mesenteroides subsp. mesenteroides was the species that accounted for the largest proportion of isolates of Leuconostoc genus. Two leuconostoc isolates stood out in the acidifying activity, with reduction in pH of 1.12 and 1.04 units. The isolates showed low proteolytic and autolytic activity. Most of the isolates were dextran producers, presented good resistance to the salt and pH conditions of the cheese and showed antimicrobial activity against cheese pathogen bacteria, and none of them produced biogenic amines.

CONCLUSION

These results allowed the selection of five strains (UEL 04, UEL 12, UEL 18, UEL 21 and UEL 28) as good candidates for use as adjunct cultures for cheese manufacture. © 2018 Society of Chemical Industry
Simultaneous determination of seven phenylethanoid glycosides in Cistanches Herba by a single marker using a new calculation of relative correction factor
Authors: Dong Yanhong , Guo Qi , Liu Jingjing , Ma Xueqin
Published: January 2018

Current quantitative analysis of multi‐components by a single marker is usually performed by using liquid chromatography methods coupled with ultraviolet or mass spectrometry detection to afford the relative correction factors between reference standard and other components. However, low durability of the relative correction factors caused by different chromatographic system leading this approach lacking a high accuracy. In the present study, a simple but effective method was established by employing the absorption coefficient () to calculate the relative correction factors instead of peak area or height. The absorption coefficient, a fundamental constant of physics, has been widely used for qualitative and quantitative analysis in Pharmacopoeia all over the world. According to the absorbance coefficient ratio between echinacoside and other compounds, the content of seven phenylethanoid glycosides in Cistanche deserticola and Cistanches tubulosa were determined simultaneously. The low standard method difference on quantitative measurement of seven compounds in Cistanches Herba between our method and the external standard method proved the consistency of the two methods. Using an ultra high performance liquid system, these seven bioactive phenylethanoid glycosides were baseline separated in 8 min. All the data suggested that the method was accurate and reliable for the determination of multi‐components when authentic standard substances were unavailable.
Review and synthesis of research investigating golden eagle electrocutions
Authors: Mojica Elizabeth K. , Dwyer James F. , Harness Richard E. , Williams Gary E. , Woodbridge Brian
Published: January 2018

Golden eagle (Aquila chrysaetos) electrocution on power poles is a global conservation problem with an estimated 504 eagles electrocuted annually in North America alone. Despite widespread use of mitigation techniques to retrofit existing poles and to build new poles to avian‐friendly standards, electrocution remains a leading anthropogenic cause of death for the golden eagle. To assist electric utilities, wildlife managers, and the public in understanding eagle electrocution risk, we reviewed and synthesized risk factors and mitigation techniques from published literature from 1940 to 2016. Eagles have 8 electrocution risk factors: pole design, eagle age, morphology, land cover and topography, prey availability, season, weather, and behavior. Pole configuration was the most frequently identified electrocution risk factor and electrocution incidents were most often associated with distribution level (<69 kV) equipment poles. Age was the second most frequently identified risk factor, with juvenile eagles electrocuted at approximately twice the rate of subadults or adults. Risk was also associated with large body size, high‐quality habitat, high prey density, winter dispersal, inclement weather, and intraspecific interactions. Risk modeling based on these factors may assist electric utilities and other stakeholders in identification of high‐risk poles at the regional scale. High‐risk poles need prioritization for retrofitting by electric utilities. Compensatory mitigation funding becoming available through eagle take permitting may be useful in offsetting costs to utilities. Electrocution mitigation efforts strategized by region to target high‐risk poles could result in substantial reductions of golden eagle annual mortalities. © 2018 The Wildlife Society.
Analysis of a PDE model of the swelling of mitochondria accounting for spatial movement
Authors: Efendiev Messoud A. , Ôtani Mitsuharu , Eberl Hermann J.
Published: January 2018

We analyze existence and asymptotic behavior of a system of semilinear diffusion‐reaction equations that arises in the modeling of the mitochondrial swelling process. The model itself expands previous work in which the mitochondria were assumed to be stationary, whereas now their movement is modeled by linear diffusion. While in the previous model certain formal structural conditions were required for the rate functions describing the swelling process, we show that these are not required in the extended model. Numerical simulations are included to visualize the solutions of the new model and to compare them with the solutions of the previous model.
Characterization methods for comprehensive evaluations of shielding materials used in an MRI
Authors: Gross‐Weege Nicolas , Dey Thomas , Gebhardt Pierre , Schug David , Weissler Bjoern , Schulz Volkmar
Published: January 2018

Purpose

In order to integrate electronic devices into a magnetic resonance imaging (MRI) scanner, shielding of the electronics with respect to the radio frequency (RF) transmit and receive system of the MRI scanner is required. Furthermore, MRI uses time‐varying low‐frequency magnetic fields for spatial encoding, i.e., the gradient magnetic fields. Time‐varying magnetic fields induce eddy currents in all conductive elements. The eddy currents result in opposing magnetic fields, which can cause distortions of the magnetic resonance (MR) image. As shielding of lower frequencies is not feasible in this respect, an ideal shielding element should be transparent for gradient magnetic fields while providing a high RF shielding effectiveness. Furthermore, it should offer a low susceptibility to prevent distortion of the main magnetic field of the MRI. In this work, we characterize the aforesaid shielding parameters of different shielding samples.

Methods

We developed a nuclear magnetic resonance (NMR) probe to measure the magnetic fields to quantify the field distortions time‐resolvedly. The relative distortion was introduced as a proportionality constant relating the eddy‐current‐inducing field changes and the field distortions. The relative distortion was measured in the frequency range from 0 to 10 kHz for all shielding samples using the NMR probe. We characterized the shielding effectiveness of the samples in the frequency range from 1 to 150 MHz using a network analyzer. We conducted all measurements with three different materials, two carbon fiber composites and copper, each in various thicknesses.

Results

The relative distortion of the magnetic fields induced by the carbon fiber composites samples was at least a factor of seven lower than the copper sample. A linear dependency on the sample thickness was measured for the main field distortion, the relative distortion and the shielding effectiveness. The relative distortion was roughly independent of the gradient frequency contrary to the shielding effectiveness, highly depending on the RF frequency.

Conclusions

We presented a very sensitive method to characterize the distortion of the main field distortion and the gradient transparency using an NMR probe. We analyzed different shielding materials regarding the main field distortion, the gradient transparency, and the shielding effectiveness. From the tested materials, we identified a carbon fiber composite with the lowest distortion on the MRI.
An adaptive MsFEM for nonperiodic viscoelastic composites
Authors: Klimczak Marek , Cecot Witold
Published: January 2018

We present a modification of the multiscale finite element method (MsFEM) for modeling of heterogeneous viscoelastic materials and an enhancement of this method by the adaptive generation of both meshes, ie, a macroscale coarse one and a microscale fine one. The fine mesh refinements are performed independently within coarse elements adjusting the microscale discretization to the microstructure, whereas the coarse mesh adaptation optimizes the macroscale approximation. Besides the coupling of the hp‐adaptive finite element method with the MsFEM we propose a modification of the MsFEM to accommodate for the analysis of transient nonlinear problems. We illustrate the efficiency and accuracy of the new approach for a number of benchmark examples, including the modeling of functionally graded material, and demonstrate the potential of our improvement for upscaling nonperiodic and nonlinear composites.
Preparation and characterization of porous cationic poly[styrene‐co‐(N,N′‐dimethylaminoethyl methacrylate)] nanoparticles and their adsorption of heavy metal ions in water
Authors: Hu Yang , Wang Lihui , Shen Jie , Jiang Guoqiang , Kan Chengyou
Published: January 2018

Using styrene (St) andN,N′‐dimethylaminoethyl methacrylate (DMAEMA) as raw materials, monodispersed P(St‐co‐DMAEMA) nanoparticles (NPs) were first prepared via semi‐continuous emulsion polymerization, and using a stepwise acid–alkali post‐treatment, porous P(St‐co‐DMAEMA) NPs were then obtained and used to adsorb heavy metal ions in aqueous phase. Results showed that the post‐treatment conditions including temperature, initial pH and time of acid–alkali treatment had significant effects on the morphology of the porous P(St‐co‐DMAEMA) NPs, with higher temperature, more extreme pH condition and longer treatment time resulting in larger pores and volume swelling ratio. Under the optimized acid–alkali post‐treatment conditions (60 °C, acid treatment at pH = 4.0 for 1 h and then alkali treatment at pH = 10.0 for 1 h), the obtained porous NPs had nearly 15 times the surface area and 1.5 times the amount of surface amino groups than the corresponding solid NPs. An analysis of the mechanism of metal ion adsorption on the porous NPs indicated that the adsorbed amount of metal ions was the result of synergistic effect of physical and chemical adsorption, which was closely related to the porous NP surface area, amount of surface of amino groups and the volume of the ions. © 2018 Society of Chemical Industry
Assessment of Energy Barriers Between ZrCuAlNi Amorphous Metal and Atomic Layer Deposition Insulators Using Internal Photoemission Spectroscopy
Authors: Jenkins Melanie A. , Klarr Tyler , Austin Dustin Z. , Li Wei , Nguyen Nhan V. , Conley John F.
Published: January 2018

The energy barrier heights between an ultra‐smooth amorphous metal electrode, ZrCuAlNi, and several atomic layer deposited (ALD) insulators are measured using internal photoemission (IPE) spectroscopy. ZrCuAlNi–insulator barriers are characterized within metal–insulator–metal (MIM) stacks with Al top contacts and results are compared with the Al/insulator barrier heights. The measured barrier heights at the ZrCuAlNi interface are found to be 3.3, 3.2, 3.0, and 2.2 eV for SiO2, Al2O3, HfO2, and ZrO2, respectively. This barrier height trend is consistent with the electron affinity of the respective oxides. However, barriers for SiO2 and Al2O3 are smaller than that ideally expected based on the reported vacuum work function of ZrCuAlNi, indicating a smaller ZrCuAlNi effective work function in these device structures. The measured Al barrier height results confirm previous reports of a negative dipole at the Al–ALD insulator interface.
Assessing robustness of factor ranking for supersaturated designs
Authors: Jang Dae‐Heung , Anderson‐Cook Christine M.
Published: January 2018

Supersaturated designs can potentially be a beneficial tool for efficiently exploring a large number of factors with a moderately sized design. However, because more factors are being considered than there are runs, the stability of the identified factors depends heavily on effect sparsity and the lack of highly influential observations. A helpful tool for the analysis of supersaturated designs is least absolute shrinkage and selection operation (LASSO), which is useful when the effects of many explanatory variables are sparse in a high‐dimensional dataset. To understand the impact of individual observations on the selected factors, the LASSO influence plot was created. This paper describes an application of this plot and its variants that can be used to identify influential points, increase understanding of the impact of individual observations on model parameters, and the robustness of results in analyses with supersaturated designs. These graphical methods can serve as a complement to other regression diagnostics techniques in the LASSO regression setting.
A general class of nonparametric control charts
Authors: Koutras Markos V. , Triantafyllou Ioannis S.
Published: January 2018

In this article, we introduce a new general class of nonparametric Shewhart‐type control charts using the lengths of runs of test sample observations between successive observations of a reference sample. Several control charts that have appeared in the literature are members of the new family. In addition, 3 new nonparametric control charts that belong to the class are introduced and studied. Numerical results depict that the proposed charts attain competitive in‐control and out‐of‐control performance as compared with existing nonparametric charts.
Decentralized stabilization of Markovian jump interconnected systems with unknown interconnections and measurement errors
Authors: Li Li‐Wei , Yang Guang‐Hong
Published: January 2018

This paper investigates the decentralized output feedback control problem for Markovian jump interconnected systems with unknown interconnections and measurement errors. Different from some existing results, the global operation modes of all subsystems are not required to be completely accessible for the decentralized control system. A decentralized dynamic output feedback controller is constructed using neighboring mode information and local outputs, where the measurement errors between actual and measured outputs are considered. Subsequently, a new design method is developed such that the resultant closed‐loop system is stochastically stable and satisfying an L∞‐norm constraint. Sufficient conditions are formulated by linear matrix inequalities, and the controller gains are characterized in terms of the solution of a convex optimization problem. Finally, an example is given to illustrate the effectiveness of the proposed theoretical results.
Data‐based conjectures for supporting responsive teaching in engineering design with elementary teachers
Authors: Watkins Jessica , McCormick Mary , Wendell Kristen Bethke , Spencer Kathleen , Milto Elissa , Portsmore Merredith , Hammer David
Published: January 2018

The national efforts underway to include engineering in K–12 science education present a variety of new challenges, including how to prepare teachers to teach a new discipline. In this paper, we focus on elementary teachers and how they enter into responsive teaching, in which they closely attend and meaningfully respond to students’ thinking. This pedagogical approach is particularly critical for teaching engineering design in ways that support students in developing original solutions to complex, dynamic problems. Drawing on 3 years of professional development that helped teachers incorporate engineering in literacy contexts, we investigated the knowledge and abilities teachers displayed for responsive teaching and how features of instructional design and classroom dynamics impacted their teaching. Throughout the project, we observed and videotaped professional development workshops and teachers’ classrooms, and interviewed teachers about their classroom experiences. We then conducted a thematic analysis across these data sources, presenting common themes as conjectures for how teachers enter into responsive teaching in engineering. We discuss how these conjectures can inform teacher research and the design of teacher preparation programs in engineering.
Ultrathin Nitrogen‐Doped Carbon Layer Uniformly Supported on Graphene Frameworks as Ultrahigh‐Capacity Anode for Lithium‐Ion Full Battery
Authors: Huang Yanshan , Li Ke , Yang Guanhui , Aboud Mohamed F. Aly , Shakir Imran , Xu Yuxi
Published: January 2018

The designable structure with 3D structure, ultrathin 2D nanosheets, and heteroatom doping are considered as highly promising routes to improve the electrochemical performance of carbon materials as anodes for lithium‐ion batteries. However, it remains a significant challenge to efficiently integrate 3D interconnected porous frameworks with 2D tunable heteroatom‐doped ultrathin carbon layers to further boost the performance. Herein, a novel nanostructure consisting of a uniform ultrathin N‐doped carbon layer in situ coated on a 3D graphene framework (NC@GF) through solvothermal self‐assembly/polymerization and pyrolysis is reported. The NC@GF with the nanosheets thickness of 4.0 nm and N content of 4.13 at% exhibits an ultrahigh reversible capacity of 2018 mA h g−1 at 0.5 A g−1 and an ultrafast charge–discharge feature with a remarkable capacity of 340 mA h g−1 at an ultrahigh current density of 40 A g−1 and a superlong cycle life with a capacity retention of 93% after 10 000 cycles at 40 A g−1. More importantly, when coupled with LiFePO4 cathode, the fabricated lithium‐ion full cells also exhibit high capacity and excellent rate and cycling performances, highlighting the practicability of this NC@GF.
The tetrapod fauna of the upper Permian Naobaogou Formation of China: a new species of Elginia (Parareptilia, Pareiasauria)
Authors: Liu Jun , Bever Gabriel S.
Published: January 2018

The pareiasaur fossil record in China is poor compared to that of Russia or South Africa. A new pareiasaur specimen is here reported from the upper Permian Naobaogou Formation of the Daqing Mountains, Nei Mongol, China. It is recognized as a new species of Elginia, a taxon otherwise known only from the upper Permian Cutties Hillock Sandstone of Scotland. Diagnostic features include a moderately developed cheek flange; prominent otic notch (formed between squamosal and quadratojugal at the posterior margin of the temporal plate); enlarged supraorbital bosses on prefrontal, postfrontal and postorbital; a hypertrophied supratemporal horn, and squamosal horn prominently projecting posteriorly from caudal margin of temporal plate. The new taxon is differentiated from E. mirabilis by a well‐developed and crescentic postfrontal boss, which is the largest among a series of circumorbital bosses; upper orbital border distinctly domed with a smooth rather than angled anterodorsal margin; lesser developed cranial bosses, basal confluence of the transverse process and postzygapophysis forms a horizontal flange in some dorsal vertebrae. The new discovery significantly extends the geographical distribution of Elginia and Elginiidae.
Improving image quality of mid‐trimester fetal sonography in obese women: role of ultrasound propagation velocity
Authors: Chauveau B. , Auclair C. , Legrand A. , Mangione R. , Gerbaud L. , Vendittelli F. , Boyer L. , Lémery D.
Published: January 2018

Objective

The quality of ultrasound images is impaired in obese patients. All ultrasound scanners are calibrated for an ultrasound propagation velocity of 1540 m/s, but the propagation in fatty tissue is slower (in the order of 1450 m/s). The main objective of this study was to evaluate the quality of images obtained with different ultrasound propagation velocity settings during the mid‐trimester fetal ultrasound examination in obese patients.

Methods

This was a cross‐sectional study using image sets of four recommended scanning planes collected from 32 obese pregnant women during their mid‐trimester fetal scan. Each image set comprised three images obtained successively at three different propagation velocity settings (1540 m/s, 1480 m/s and 1420 m/s). A panel of 114 experts assessed the quality of 100 image sets, grading them from A (most acceptable) to C (least acceptable). Scanning‐plane‐specific indicators of adiposity (fatty layer thickness, probe‐to‐organ distance) were analyzed for each scanning plane.

Results

The experts had a mean of 18.1 ± 10.2 years of experience. The grade distribution (A, B, C) differed significantly (P < 0.0001) between the three propagation velocity settings tested; at the lower speed of 1480 m/s, images were most often graded A, while at the conventional speed of 1540 m/s, they were most often graded C. Regardless of the scanning plane, the thicker the fatty layer of the abdominal wall in a given plane, the lower the preferred speed (P < 0.0001).

Conclusion

The construction of images taking into account ultrasound propagation velocities lower than 1540 m/s can improve significantly the quality of images obtained during mid‐trimester fetal ultrasonography in obese women. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.
Long-term physical activity leads to a significant increase in serum sRAGE levels: a sign of decreased AGE-mediated inflammation due to physical activity?
Authors: Sponder Michael , Campean Ioana-Alexandra , Emich Michael , Fritzer-Szekeres Monika , Litschauer Brigitte , Graf Senta , Dalos Daniel , Strametz-Juranek Jeanette
Published: January 2018

There is growing evidence that low levels of the circulating soluble receptor of advanced glycation end products (sRAGE) are a valuable predictor of cardiovascular disease (CVD). The aim of this prospective study was to investigate the influence of long-term physical activity on serum sRAGE levels. 109 subjects were recruited, and 98 completed the study. Participants were asked to perform exercise within the calculated training pulse for 8 months. The performance gain was measured/quantified by bicycle stress tests at the beginning and end of the observation period. sRAGE was measured at baseline and after 2/6/8 months by ELISA. Backwards, multiple linear regression analysis was performed to investigate the association of co-variables age, sex, BMI, and performance at baseline, HbA1c, and lipoprotein a with baseline sRAGE levels. We identified BMI and lipoprotein a as significant predictors for baseline sRAGE levels. Compared to subjects with a performance gain ≤ 4.9% subjects with a gain > 5% showed a significant increase in sRAGE levels up to 22%. sRAGE serum levels correlate negatively with lipoprotein a levels and BMI and long-term physical activity leads to a significant increase in serum sRAGE levels (9–22%), whereby the sRAGE increase is most pronounced in subjects with initially low-performance levels, suggesting that in particular, these subject profit the most from increased physical activity. The sport-mediated increase of sRAGE might be a sign of decreased AGE-mediated inflammation and highlight the protective effect of sports on CVD and other disease which are at least partly mediated by an increased inflammation status.

Clinical trials registrationNCT02097199.
Engineering co-culture system for production of apigetrin in Escherichia coli
Authors: Thuan Nguyen Huy , Chaudhary Amit Kumar , Van Cuong Duong , Cuong Nguyen Xuan
Published: January 2018

Microbial cells have extensively been utilized to produce value-added bioactive compounds. Based on advancement in protein engineering, DNA recombinant technology, genome engineering, and metabolic remodeling, the microbes can be re-engineered to produce industrially and medicinally important platform chemicals. The emergence of co-culture system which reduces the metabolic burden and allows parallel optimization of the engineered pathway in a modular fashion restricting the formation of undesired byproducts has become an alternative way to synthesize and produce bioactive compounds. In this study, we present genetically engineered E. coli-based co-culture system to the de novo synthesis of apigetrin (APG), an apigenin-7-O-β-d-glucopyranoside of apigenin. The culture system consists of an upstream module including 4-coumarate: CoA ligase (4CL), chalcone synthase, chalcone flavanone isomerase (CHS, CHI), and flavone synthase I (FNSI) to synthesize apigenin (API) from p-coumaric acid (PCA). Whereas, the downstream system contains a metabolizing module to enhance the production of UDP-glucose and expression of glycosyltransferase (PaGT3) to convert API into APG. To accomplish this improvement in titer, the initial inoculum ratio of strains for making the co-culture system, temperature, and media component was optimized. Following large-scale production, a yield of 38.5 µM (16.6 mg/L) of APG was achieved. In overall, this study provided an efficient tool to synthesize bioactive compounds in microbial cells.