bluuebunny/crossref_metadata_2025 huggingface dataset:
Tissue characterization of uterine fibroids with an intravoxel incoherent motion model: The need for T2 correction
Authors: Qu Feifei , Hor Pei‐Herng , Fischer John , Muthupillai Raja
Published: March 2018

Background

Diminished signal intensity of uterine fibroids in T2‐weighted images is routinely used as a qualitative marker of fibroid hypoperfusion. However, quantitative classification of fibroid perfusion with intravoxel incoherent motion (IVIM) model‐based metrics is not yet clinically accepted.

Purpose

To investigate the influence of T2 correction on the estimation of IVIM model parameters for characterizing uterine fibroid tissue.

Study Type

Prospective.

Population

Fourteen women with 41 fibroids (12 Type I and 29 Type II, per Funaki classification) underwent diffusion‐weighted imaging and T2 mapping.

Field Strength

Diffusion‐weighted images (b values: 0, 20, 40, 60, 100, 200, 400, 600, 800, 1000 s/mm2) and T2 maps were obtained at 1.5T.

Assessment

The effect of uterine fibroid T2 variation on IVIM model parameters (diffusion coefficient, perfusion coefficient, and perfusion volume fraction) were numerically modeled and experimentally evaluated without (D, D*, f) and with (Dc,
, fc) T2 correction. The relationship of T2 with D and the T2‐corrected perfusion volume fraction (fc) was also examined.

Statistical Test

D‐values and f‐values estimated with and without T2 correction were compared by using a two‐tailed Student's t‐test.

Results

Type II fibroids had higher D and f than Type I fibroids, but the differences were not significant (Type I vs. Type II, D: 0.83 ± 0.20 vs. 0.80 ± 0.25 mm2/s, P = 0.78; f: 23.64 ± 4.87% vs. 25.27 ± 7.46%, P = 0.49). For Type I and Type II fibroids, fc was lower than f, and fc of Type II fibroids was significantly higher than that of Type I fibroids (Type I vs. Type II, fc: 7.80 ± 1.88% vs. 11.82 ± 4.13%, P = 0.003). Both D and fc exponentially increased with the increase of fibroid T2 as functions:
and
respectively. D asymptotically approached 1.79 × 10−3 mm2/s, and fc approached 21.74%.

Data Conclusion

T2 correction is important when using IVIM‐based models to characterize uterine fibroid tissue.

Level of Evidence: 2

Technical Efficacy: Stage 1

J. Magn. Reson. Imaging 2018;48:994–1001.
Evaluation of noncontrast MR enterography for pediatric inflammatory bowel disease assessment
Authors: Lanier Michael Hunter , Shetty Anup S. , Salter Amber , Khanna Geetika
Published: March 2018

Background

Gadolinium deposition in normal tissues is being increasingly recognized. Children with inflammatory bowel disease (IBD) undergo frequent imaging with contrast‐enhanced MR enterography (MRE).

Purpose

To determine the impact of intravenous (IV) gadolinium in assessment of pediatric IBD by MRE.

Study Type

Retrospective, case series.

Population

Radiology information system was searched to identify all children who underwent MRE and endoscopy within 30 days in 2016.

Field Strength/Sequence

1.5T and 3T.

Assessment

Imaging studies were evaluated for bowel inflammation interpreted by two blinded radiologists in two sessions 6 weeks apart (session 1 pre‐MRE; session 2 pre/postcontrast‐MRE). Endoscopic histology was the reference standard.

Statistical Tests

A logistic regression model was evaluated using receiver operating characteristics curves and expressed by c‐statistics. Agreement between readers was evaluated using Cohen's or weighted kappa statistic, as appropriate. Two‐sided P < 0.05 was considered statistically significant. Descriptive statistics were used for assessment of IBD complications.

Results

In all, 52 children (46% female), mean age 13.2 (SD 3.42) years formed the study cohort. 77% (40/52) had inflammation on endoscopic biopsy. Pre/post‐MRE showed no significant increase in the c‐statistic compared to pre‐MRE for assessment of small bowel (Reader 1 P = 0.56, Reader 2 P = 1.00) or large bowel inflammation (Reader 1 P = 0.42, Reader 2 P = 1.00)). Intravenous contrast showed no improvement in interobserver agreement for assessment of inflammation in small (kappa 0.92 pre‐MRE, 0.88 pre/post‐MRE) or large bowel (kappa 0.83 pre‐MRE, 0.73 pre/post‐MRE). IV contrast had no meaningful impact on interobserver agreement for length of small bowel inflamed (intraclass correlation coefficient 0.90 pre‐MRE, 0.95 pre/post‐MRE). Assessment of IBD complications was improved with IV contrast, with 3/5 cases with perianal penetrating disease not recognized on pre‐MRE.

Data Conclusion

Routine administration of IV gadolinium has no impact on the assessment of bowel inflammation. However, there is potential for missing perianal complications using a noncontrast MRE protocol without dedicated pelvic imaging.

Level of Evidence: 3

Technical Efficacy: Stage 2

J. MAGN. RESON. IMAGING 2018;48:341–348.
Comparison of 3He and 129Xe MRI for evaluation of lung microstructure and ventilation at 1.5T
Authors: Stewart Neil J. , Chan Ho‐Fung , Hughes Paul J.C. , Horn Felix C. , Norquay Graham , Rao Madhwesha , Yates Denise P. , Ireland Rob H. , Hatton Matthew Q. , Tahir Bilal A. , Ford Paul , Swift Andrew J. , Lawson Rod , Marshall Helen , Collier Guilhem J. , Wild Jim M.
Published: March 2018

Background

To support translational lung MRI research with hyperpolarized 129Xe gas, comprehensive evaluation of derived quantitative lung function measures against established measures from 3He MRI is required. Few comparative studies have been performed to date, only at 3T, and multisession repeatability of 129Xe functional metrics have not been reported.

Purpose/Hypothesis

To compare hyperpolarized 129Xe and 3He MRI‐derived quantitative metrics of lung ventilation and microstructure, and their repeatability, at 1.5T.

Study Type

Retrospective.

Population

Fourteen healthy nonsmokers (HN), five exsmokers (ES), five patients with chronic obstructive pulmonary disease (COPD), and 16 patients with nonsmall‐cell lung cancer (NSCLC).

Field Strength/Sequence

1.5T. NSCLC, COPD patients and selected HN subjects underwent 3D balanced steady‐state free‐precession lung ventilation MRI using both 3He and 129Xe. Selected HN, all ES, and COPD patients underwent 2D multislice spoiled gradient‐echo diffusion‐weighted lung MRI using both hyperpolarized gas nuclei.

Assessment

Ventilated volume percentages (VV%) and mean apparent diffusion coefficients (ADC) were derived from imaging. COPD patients performed the whole MR protocol in four separate scan sessions to assess repeatability. Same‐day pulmonary function tests were performed.

Statistical Tests

Intermetric correlations: Spearman's coefficient. Intergroup/internuclei differences: analysis of variance / Wilcoxon's signed rank. Repeatability: coefficient of variation (CV), intraclass correlation (ICC) coefficient.

Results

A significant positive correlation between 3He and 129Xe VV% was observed (r = 0.860, P < 0.001). VV% was larger for 3He than 129Xe (P = 0.001); average bias, 8.79%. A strong correlation between mean 3He and 129Xe ADC was obtained (r = 0.922, P < 0.001). MR parameters exhibited good correlations with pulmonary function tests. In COPD patients, mean CV of 3He and 129Xe VV% was 4.08% and 13.01%, respectively, with ICC coefficients of 0.541 (P = 0.061) and 0.458 (P = 0.095). Mean 3He and 129Xe ADC values were highly repeatable (mean CV: 2.98%, 2.77%, respectively; ICC: 0.995, P < 0.001; 0.936, P < 0.001).

Data Conclusion

129Xe lung MRI provides near‐equivalent information to 3He for quantitative lung ventilation and microstructural MRI at 1.5T.

Level of Evidence: 3

Technical Efficacy Stage 2

J. Magn. Reson. Imaging 2018;48:632–642.
High Signal in Bone Marrow on Diffusion‐Weighted Imaging of Female Pelvis: Correlation With Anemia and Fibroid‐Associated Symptoms
Authors: Chen Ying‐Yuan , Wu Ching‐Lan , Shen Shu‐Huei
Published: March 2018

Background

The diffusion‐weighted imaging (DWI) signals of the female pelvic bone marrow show great variability and are usually high in female patients with fibroid‐associated symptoms and anemia.

Purpose

To ascertain clinical factors contributing to high signal intensity in the bone marrow of the female pelvis on DWI.

Study Type

Retrospective case–control study.

Subjects

A single‐institution review of 221 female patients underwent a pelvic magnetic resonance study from December 2012 to July 2014.

Field Strength/Sequence

1.5T/DWI (b = 0 and 1000) and apparent diffusion coefficient (ADC).

Assessment

The ADC of pelvic bone marrow and the muscle‐normalized signal intensity (SI) on DWI (mnDWI) were measured. A brightness grading scale ranging from 0 to 4 was used for pelvic bone assessment. Clinical factors, namely, age, the lowest hemoglobin level in the last 6 months, the presence of large uterine fibroids, and/or adenomyosis and fibroid‐associated symptoms were recorded.

Statistical Tests

The relationships between the brightness grade and clinical factors were evaluated through multinomial logistic regression, and correlations of mnDWI and the ADC with the clinical factors were analyzed through the Kruskal–Wallis test, Jonckheere's trend test, and the Mann–Whitney U‐test with Bonferroni correction.

Results

Age and the hemoglobin level were inversely associated with the bone marrow brightness grade on DWI (both P < 0.05), whereas the presence of fibroid‐associated symptoms showed a positive association (P = 0.028). The ADC and mnDWI in women younger than 50 years were significantly higher than those in older women (both P < 0.0001). The ADC had no significant correlation with anemia (P = 0.511), whereas mnDWI increased as the severity of anemia increased (P = 0.00154).

Data Conclusion

Our study showed an association of high DWI SI of pelvic bone marrow with anemia in premenopausal women.

Level of Evidence: 4

Technical Efficacy Stage 3

J. Magn. Reson. Imaging 2018;48:1024–1033.
The Role of Character Strengths and Importance of Family on Mexican American College Students' Career Decision Self‐Efficacy
Authors: Vela Javier Cavazos , Sparrow Gregory Scott , Whittenberg James F. , Rodriguez Basilio
Published: March 2018

This study examined how character strengths and the importance of family influenced Mexican American college students' (N = 129) career decision self‐efficacy. Findings from a multiple regression analysis indicated that psychological grit and curiosity were significant predictors of career decision self‐efficacy. The authors discuss the importance of these findings and provide recommendations for future research.
Self‐assembling peptide matrix for treatment of dentin hypersensitivity: A randomized controlled clinical trial
Authors: Schlee Markus , Rathe Florian , Bommer Claudine , Bröseler Frank , Kind Lucy
Published: March 2018

Background

Patient‐reported dentin hypersensitivity [DHS] pain is a common finding linked with periodontal disease. This pilot clinical study investigates a novel therapeutic regimen using self‐assembling peptide matrix [SAPM] gel (test) compared with use of an 8% arginine and calcium carbonate [ACC] toothpaste (control) for treatment of DHS.

Methods

A total of 50 patients with history of supportive periodontal therapy were enrolled in this prospective, randomized monocentric clinical study, of which 45 (test: n = 22; control: n = 23) fulfilled all the study visits. Test group patients performed ex‐office application of SAPM gel over 1 week, while control group patients performed ex‐office application of ACC toothpaste over 90 days. DHS was assessed in office by Visual Analog Scale [VAS], and patient's perception of pain relief was evaluated by questionnaire. In support of the clinical data, scanning electron microscopy images were recorded to investigate tubule occlusion of both control and test product.

Results

Both SAPM and ACC significantly reduced DHS in patients throughout the study, with the patient questionnaire indicating higher patient satisfaction at the earlier time points for the test group.

Conclusions

Both SAPM gel and ACC toothpaste were successful in providing relief from DHS and showed similar outcomes on VAS and verbal response scale (VRS) throughout the study period of 90 days. The new therapeutic regimen using SAPM resulted in higher patient satisfaction at day 7, as indicated by the patient questionnaire and the higher number of pain‐free patients at day 7 and day 90. This is a pilot study describing a novel therapy for DHS.
Chemical modifications of Tonda Gentile Trilobata hazelnut and derived processing products under different infrared and hot‐air roasting conditions: a combined analytical study
Authors: Binello Arianna , Giorgis Marta , Cena Clara , Cravotto Giancarlo , Rotolo Laura , Oliveri Paolo , Malegori Cristina , Cavallero Maria Chiara , Buso Stefania , Casale Monica
Published: March 2018

BACKGROUND

For the processing industry, it is crucial to know what effect the roasting process and conditions have on hazelnut quality. The present study investigates, for the first time, the effects of hot‐air and infrared (IR) roasting at different time–temperature combinations on Tonda Gentile Trilobata hazelnut: whole kernels and derived processing products (paste and oil).

RESULTS

The nutritional and physical characteristics of hazelnuts and processing products were investigated to determine the influence of the different roasting conditions as a function of intended use. The antioxidant profile (2.2‐diphenyl‐1‐picrylhydrazyl radical, oxygen radical absorbance capacity and total phenolic content) were analyzed on roasted hazelnut and paste extracts. For a comprehensive understanding of the complex biochemical phenomena occurring during roasting, E‐nose and near‐IR spectroscopy were also applied. All analytical data were processed using univariate and multivariate data analyses. Hazelnuts derived from IR roasting at higher temperatures (195 °C) showed a richer antioxidant profile and a more intense flavour. On the other hand, the yield associated with the oil extraction under the same conditions was unsatisfactory, making this process completely inadequate for oil production. Oil obtained by hot‐air roasting and IR roasting at lower temperature (135 °C) was found to be of good quality, showing rather similar acidity grade, peroxide number and acidic composition. In particular, a slightly but significantly lower acidity was related to lower roasting temperatures (0.21–0.22% versus 0.27% for higher temperatures). All roasting conditions tested allowed the quantitative homogeneous hazelnut paste to be obtained and, from a rheological point of view, a higher roasting temperatures resulted in pastes characterized by higher density and viscosity values.

CONCLUSION

The use of IR was found to be a promising alternative method for hazelnut roasting, as a result of its capability with respect to preserving nutritional values and enhancing organoleptic quality. © 2018 Society of Chemical Industry
Synthesis and characterization of pH‐responsive mesoporous chitosan microspheres loaded with sodium phytate for smart water‐based coatings
Authors: Liu Xiaojie , Li Weihua , Wang Wei , Song Liying , Fan Weijie , Gao Xiang , Xiong Chuansheng
Published: March 2018

Mesoporous micro‐ or nanocontainers have been indicated to be potential carriers of corrosion inhibitors to modify water‐based coatings for self‐healing properties and excellent anti‐corrosion performance. In this work, the eco‐friendly mesoporous chitosan microspheres loaded with green corrosion inhibitor sodium phytate were incorporated in self‐healing water‐based polyacrylate coating. The microspheres with mesoporous surface, uniform size, and promising pH responsiveness were prepared via the water‐in‐oil (W/O) emulsion chemical cross‐linking method. On this basis, chitosan microspheres loaded with 25.79 wt% sodium phytate were obtained by negative pressure impregnation method and the pH‐responsive was demonstrated by the electrochemical impedance spectroscopy (EIS). The results of EIS and seawater immersion tests revealed that artificial defected water‐based polyacrylate coating containing 5 wt% chitosan microspheres showed high anti‐corrosion performance and exhibited self‐healing capabilities due to the release of corrosion inhibitor sodium phytate.
Investigation of polyacrylamide containing capsaicin monomer as a novel corrosion inhibitor for mild steel in hydrochloric acid
Authors: Sun Xujin , Yu Liangmin
Published: March 2018

Polyacrylamide containing capsaicin‐derived monomer P(AM‐MAA‐AMPS‐HDDE‐SA) (PAMAHS) was investigated as a novel green polymer inhibitor for Q235 mild steel at 298 K in 1 M hydrochloric acid solution. Weight loss measurements, electrochemical techniques, and surface investigation methods were conducted to evaluate the inhibition performance and mechanism. The results indicated that the green inhibitor performed well in inhibiting the corrosion of mild steel and that the inhibition efficiency increased with the increase in the PAMAHS concentration. The polarization curves revealed that PAMAHS functions as a mixed‐type inhibitor. The outstanding anticorrosion effects could contribute to the PAMAHS molecule film adsorbed on the metal surface following a Langmuir adsorption isotherm, and the hydrophobic groups played an important role in protecting the metal surfaces from corrosion media.
Controlled Polymerization of Isoprene with Chromium‐Based Metal‐Organic Framework Catalysts: Switching from Cyclic to cis‐1,4‐Selectivity Depending on Activator
Authors: Gao Fei , Zhang Li , Yu Chao , Yan Xinwen , Zhang Shaowen , Li Xiaofang
Published: March 2018

Chromium‐based metal‐organic framework (MOF) Cr‐MIL‐100/101 activated by activator and aluminum trialkyl compound serve as unique, highly efficient heterogeneous single‐site catalysts for the controlled polymerization of isoprene, which not only exhibit quasi‐living nature in isoprene polymerization but also unprecedentedly switch from cyclic to cis‐1,4‐selectivity depending on the activator used to yield low molecular weight cyclic PIPs or extremely high molecular weight cis‐1,4‐PIPs. Such heterogeneous Cr‐MOF catalysts can be recycled approximately five times. Based on nitrogen sorption isotherm tests and powder X‐ray diffraction, a cationic mechanism is suggested, in which the polymerization takes place inside the open nanochannels of MOF catalysts and the space confinement effect of narrow open nanochannels originated from the coordination of PhNMe2 from activator [PhNHMe2][B(C6F5)4] with the multiple metal centers of MOF catalysts might give a rational explanation for such controlled adjustment on the PIP's structure and properties.
Influence of nitrate and nitrite concentration on N2O production via dissimilatory nitrate/nitrite reduction to ammonium in Bacillus paralicheniformis LMG 6934
Authors: Sun Yihua , De Vos Paul , Willems Anne
Published: March 2018

Until now, the exact mechanisms for N2O production in dissimilatory nitrate/nitrite reduction to ammonium (DNRA) remain underexplored. Previously, we investigated this mechanism in Bacillus licheniformis and Bacillus paralicheniformis, ubiquitous gram‐positive bacteria with many industrial applications, and observed significant strain dependency and media dependency in N2O production which was thought to correlate with high residual NO2−. Here, we further studied the influence of several physicochemical factors on NO3− (or NO2−) partitioning and N2O production in DNRA to shed light on the possible mechanisms of N2O production. The effects of NO3− concentrations under variable or fixed C/N‐NO3− ratios, NO2− concentrations under variable or fixed C/N‐NO2− ratios, and NH4+ concentrations under fixed C/N‐NO3− ratios were tested during anaerobic incubation of soil bacterium B. paralicheniformis LMG 6934 (previously known as B. licheniformis), a strain with a high nitrite reduction capacity. Monitoring of growth, NO3−, NO2−, NH4+ concentration, and N2O production in physiological tests revealed that NO3− as well as NO2− concentration showed a linear correlation with N2O production. Increased NO3− concentration under fixed C/N‐NO3− ratios, NO2− concentration, and NH4+ concentration had a significant positive effect on NO3− (or NO2−) partitioning ([N–NH4+]/[N–N2O]) toward N2O, which may be a consequence of the (transient) accumulation and subsequent detoxification of NO2−. These findings extend the information on several physiological parameters affecting DNRA and provide a basis for further study on N2O production during this process.
Bone vascularized composite allotransplantation model in swine tibial defect: Evaluation of surgical angiogenesis and transplant viability
Authors: Kotsougiani Dimitra , Hundepool Caroline A. , Bulstra Liselotte F. , Friedrich Patricia F. , Shin Alexander Y. , Bishop Allen T.
Published: March 2018

Introduction

In prior small animal studies, we maintained vascularized bone allotransplant viability without long‐term immunotherapy. Instead, an autogenous neoangiogenic circulation is created from implanted vessels, sufficient to maintain bone viability with only 2 weeks immunosupression. Blood flow is maintained despite rejection of the allogeneic vascular pedicle thereafter. We have previously described a large animal (swine) pre‐clinical model, reconstructing tibial defects with vascularized tibial allotransplants. In this manuscript, autologous angiogenesis is evaluated in this model and correlated with bone viability.

Materials and methods

Allogeneic tibial segments were transplanted across a major swine leukocyte antigen mismatch. Microvascular repair of the bone VCA pedicle was combined with intraosseous implantation of an autogenous arteriovenous (AV) bundle. The bundle was ligated in group 1 (n = 4), and allowed to perfuse in group 2 (n = 4). Three‐drug immunotherapy was given for 2 weeks. At 16 weeks micro‐CT angiography quantified neoangiogenic vessel volume. Bone viability, rejection grade, and bone healing were analyzed.

Results

A substantial neoangiogenic circulation developed from the implanted AV‐bundle in group 2, with vessel density superior to ligated AV‐bundle controls (0.11 ± 0.05 vs. 0.01 ± 0.01, P = .029). Bone allotransplant viability was also significantly enhanced by neoangiogenesis (78.7 ± 4.4% vs. 27.7 ± 5.8%, P = .028) with higher bone healing scores (21.4 ± 2.9 vs. 12.5 ± 3.7, P = .029). Ligated control tibias demonstrated disorganized bone morphology and higher local inflammation (P = .143).

Conclusion

Implantation of autogenous AV bundles into vascularized bone allotransplants resulted in the rapid formation of a neoangiogenic autogenous blood supply in a swine tibia model that maintained bone viability, improved bone healing, and minimized rejection.
Synchronization and antisynchronization of N‐coupled fractional‐order complex chaotic systems with ring connection
Authors: Jiang Cuimei , Zhang Fangfang , Li Tongxing
Published: March 2018

This paper is devoted to investigate synchronization and antisynchronization of N‐coupled general fractional‐order complex chaotic systems described by a unified mathematical expression with ring connection. By means of the direct design method, the appropriate controllers are designed to transform the fractional‐order error dynamical system into a nonlinear system with antisymmetric structure. Thus, by using the recently established result for the Caputo fractional derivative of a quadratic function and a fractional‐order extension of the Lyapunov direct method, several stability criteria are derived to ensure the occurrence of synchronization and antisynchronization among N‐coupled fractional‐order complex chaotic systems. Moreover, numerical simulations are performed to illustrate the effectiveness of the proposed design.
De novo neurogenic bladder dysfunction after salvage lymph node dissection in patients with nodal recurrence of prostate cancer
Authors: Hanske Julian , Müller Guido , van Ophoven Arndt , von Landenberg Nicolas , Roghmann Florian , Palisaar Rein‐Jüri , von Bodman Christian , Noldus Joachim , Brock Marko
Published: March 2018

Aims

To examine the impact of Salvage lymph node dissection (SLND) on bladder function and oncological outcome in hormone naïve patients with nodal recurrence of prostate cancer (PCa) after radical prostatectomy (RP).

Methods

In a prospective study between October 2015 and November 2016, 20 patients underwent transperitoneal SLND for nodal recurrence of PCa after RP at our institution. Standardized urodynamics were performed pre‐ and postoperatively after 6 weeks, 3, and 6 to 12 months. Prostate‐specific antigen (PSA) levels were used to monitor the oncological outcome. Perioperative outcomes encompassed, among others, type of complications after surgery classified to Clavien‐Dindo.

Results

The proportion of patients with neurogenic bladder dysfunction was postoperative at 6 weeks, 3, and 6 to 12 months 78.5%, 70%, and 45.5%, respectively. Compared to preoperative urodynamics, follow‐ups revealed a statistical significant cleavage of bladder wall compliance until six to twelve months after SLND (34.5 vs 22 mL/cmH2O, P = 0.044). Referring to the oncological outcome all patients experienced a PSA progression, 10 patients (50%) within 11 weeks after surgery. Overall, four patients (20%) suffered from a postoperative complication after SLND, which comprises Clavien grade I‐IIIa.

Conclusions

Transperitoneal SLND, as a treatment option for patients with nodal recurrence of PCa after RP reveals additional potential pitfalls than previously reported. Urodynamics reveal a significant impact of SLND on postoperative functional bladder dysfunctions. Therefore, informed consent prior to SLND should include the risk of persistent low compliance bladder.
Perturbation analysis in finite LD‐QBD processes and applications to epidemic models
Authors: Gómez‐Corral A. , López‐García M.
Published: March 2018

In this paper, our interest is in the perturbation analysis of level‐dependent quasi‐birth‐and‐death (LD‐QBD) processes, which constitute a wide class of structured Markov chains. An LD‐QBD process has the special feature that its space of states can be structured bylevels(groups of states), so that a tridiagonal‐by‐blocks structure is obtained for its infinitesimal generator. For these processes, a number of algorithmic procedures exist in the literature in order to compute several performance measures while exploiting the underlying matrix structure; among others, these measures are related to first‐passage times to a certain levelL(0) and hitting probabilities at this level, the maximum level visited by the process before reaching states of levelL(0), and the stationary distribution. For the case of a finite number of states, our aim here is to develop analogous algorithms to the ones analyzing these measures, for their perturbation analysis. This approach uses matrix calculus and exploits the specific structure of the infinitesimal generator, which allows us to obtain additional information during the perturbation analysis of the LD‐QBD process by dealing with specific matrices carrying probabilistic insights of the dynamics of the process. We illustrate the approach by means of applying multitype versions of the susceptible‐infective (SI) and susceptible‐infective‐susceptible (SIS) epidemic models to the spread of antibiotic‐sensitive and antibiotic‐resistant bacterial strains in a hospital ward.
The Child Adolescent Bullying Scale (CABS): Psychometric evaluation of a new measure
Authors: Strout Tania D. , Vessey Judith A. , DiFazio Rachel L. , Ludlow Larry H.
Published: March 2018

While youth bullying is a significant public health problem, healthcare providers have been limited in their ability to identify bullied youths due to the lack of a reliable, and valid instrument appropriate for use in clinical settings. We conducted a multisite study to evaluate the psychometric properties of a new 22‐item instrument for assessing youths’ experiences of being bullied, the Child Adolescent Bullying Scale (CABS). The 20 items summed to produce the measure's score were evaluated here. Diagnostic performance was assessed through evaluation of sensitivity, specificity, predictive values, and area under receiver operating characteristic (AUROC) curve. A sample of 352 youths from diverse racial, ethnic, and geographic backgrounds (188 female, 159 male, 5 transgender, sample mean age 13.5 years) were recruited from two clinical sites. Participants completed the CABS and existing youth bullying measures. Analyses grounded in classical test theory, including assessments of reliability and validity, item analyses, and principal components analysis, were conducted. The diagnostic performance and test characteristics of the CABS were also evaluated. The CABS is comprised of one component, accounting for 67% of observed variance. Analyses established evidence of internal consistency reliability (Cronbach's α = 0.97), construct and convergent validity. Sensitivity was 84%, specificity was 65%, and the AUROC curve was 0.74 (95% CI: 0.69–0.80). Findings suggest that the CABS holds promise as a reliable, valid tool for healthcare provider use in screening for bullying exposure in the clinical setting.
Mechanical and dynamic mechanical analysis of jute and human hair‐reinforced polymer composites
Authors: Selvakumar Kathiresan , Meenakshisundaram Omkumar
Published: March 2018

Application of light‐weight materials in automotive and structural components such as door panel, Dashboard and internal engine cover play a crucial role in the improvement of vehicle performance. Weight reduction of automotive vehicle components results in less fuel consumption, leading to drastic reduction of CO2 emission. Carbon emission can be minimized through replacement of light‐weight natural fiber reinforced composite‐based components in place of metallic components in the vehicles. Simultaneous application of heat and dynamic loads on polymer composite materials affect crystallinity resulting in the degradation of material properties and its weight. Many researchers have shown interest in the use of bio composites for automotive parts with good mechanical and thermal properties for conventional automotive materials. The present work focuses on the fabrication of jute and human hair‐reinforced epoxy‐based polymer composites with five different fiber compositions. Mechanical properties such as tensile strength and impact energy were analyzed. Storage modulus, loss modulus and damping behavior under different frequencies constituting a function of increasing temperature was observed. The effect of fiber composition and frequency on dynamic behavior of new combination of natural composites was analyzed for determining the viscoelastic behavior of composites. Mechanical properties were found to increase with increase in human hair composition in the composites. The glass transition temperature (Tg) obtained from storage modulus, loss modulus and damping curve exhibits a temperature between 80 and 95°C for all composites. As a consequence, higher fiber content in matrix was observed to allow greater stress transfer at the interface resulting in high dynamic mechanical properties. The experimental results have shown that the natural fiber‐reinforced polymer composite is sustainable in withstanding dynamic loads. POLYM. COMPOS., 40:1132–1141, 2019. © 2018 Society of Plastics Engineers
Polymer etching by atmospheric‐pressure plasma jet and surface micro‐discharge sources: Activation energy analysis and etching directionality
Authors: Knoll Andrew J. , Luan Pingshan , Pranda Adam , Bruce Robert L. , Oehrlein Gottlieb S.
Published: March 2018

Treatments of polymer films using either a MHz atmospheric pressure plasma jet (APPJ) or an atmospheric pressure surface micro‐discharge (SMD) plasma are investigated. While the typical approach to determine relevant reactive species is to correlate surface effects with gas phase species measurement, this does not capture potential synergistic or other complex effects that may be occurring. Activation energy and directionality of the etching process can characterize what is occurring at the surface for these processes in more detail. The APPJ source shows an apparent activation energy of ∼0.18 eV at 8 mm distance and up to ∼0.34 eV at 16 mm distance for a temperature range of 20–80 °C tested with thin polymer films. The APPJ source shows directional etching at 8 mm distance with less anisotropy the more distance is increased. The SMD source has an apparent activation energy of ∼0.8–0.9 eV at a distance of 3 mm. The SMD also only shows isotropic etching behavior. However the SMD surface chemistry changes significantly to less oxidation with increased temperature while the APPJ source induced modifications remain very similar with temperature change. The lower apparent activation energy of the APPJ‐induced etching reactions as compared with low pressure work (0.5 eV) and observation of line‐of‐sight contribution to etching suggests the involvement of a directional species at closer distances facilitating the etching which falls off with increasing distance. The high activation energy of the SMD suggests that species with less capability for etching is responsible compared to the APPJ and low pressure plasma. The high surface oxidation from low temperature SMD treatments shows that the surface is being oxidized but not sufficiently to reach the desorption step of the etching process.
Energetic Compounds Based on 3,4‐Bis(4‐nitramino‐ 1,2,5‐oxadiazol‐3‐yl)‐1,2,5‐furoxan (BNAFF)
Authors: Gospodinov Ivan , Hermann Tobias , Klapötke Thomas M. , Stierstorfer Jörg
Published: March 2018

3,4‐Bis(4‐amino‐1,2,5‐oxadiazol‐3‐yl)‐1,2,5‐furoxan (BAFF,1) was nitrated in 100 % HNO3at −10 °C and then reacted with KOH to give the corresponding energetic dipotassium salt of 3,4‐bis(4‐nitramino‐1,2,5‐oxadiazol‐3‐yl)‐1,2,5‐furoxan (2, K2BNAFF). The neutral nitramino‐furoxan compound (3, H2BNAFF) is unstable at room temperature and can be obtained from K2BNAFF with 2 mHCl and ether as H2BNAFF ⋅ 0.5 Et2O. Several nitrogen‐rich salts (e. g. ammonium, guanidinium, aminoguanidinium, hydrazinium and hydroxylammonium) were prepared from K2BNAFF. The potassium, guanidinium, aminoguanidinium, hydroxylammonium and silver salts of BNAFF were characterized by low‐temperature X‐ray diffraction. In addition, all compounds were analyzed by vibrational spectroscopy (IR and Raman), multinuclear (1H,13C,14N) NMR spectroscopy, differential thermal analysis (DTA) and elemental analysis. The heats of formation for the anhydrous compounds were calculated using the atomization method based on CBS‐4 M enthalpies. Several detonation parameters were predicted by using the EXPLO5 code (V6.03). In addition, the sensitivities of all BNAFF salts toward friction, impact and electrostatic discharge were determined.
The ethnoracial context of residential mobility in France: Neighbourhood out‐migration and relocation
Authors: McAvay Haley
Published: March 2018

Recent research from France has used census data to explore patterns of residential segregation among immigrants and natives. Yet few studies explore how residential mobility underpins these patterns. This article draws on recent panel data (1990–2013) to explore how the ethnoracial composition of neighbourhoods impacts moving among first and second generation immigrants and natives. Two hypotheses are explored:ethnic clustering, or reduced out‐mobility of immigrants and their offspring from coethnic neighbourhoods, andnative flight,or the departure of natives from immigrant neighbourhoods. This article is the only to measure these processes in France at the neighbourhood level, on both first and second generation immigrants, using panel models that control for individual and neighbourhood heterogeneity. The findings document a significant negative effect of the neighbourhood coethnic share on moving out among first and second generation immigrants that remains strong over all time periods. In contrast, the French majority are more likely to exit areas with increasing shares of immigrants, except in models controlling for unobserved neighbourhood characteristics. Moving destinations across groups are also analysed and show that non‐Europeans enter neighbourhoods with substantially higher immigrant shares net of controls.
Modulating the Effect of Yttrium Doping on the Structural and Dielectric Properties of Barium Titanate
Authors: Kumar Sachin , Thakur Om Prakash , Luthra Vandna
Published: March 2018

In this paper, the influence of yttrium doping on the structural, dielectric, and piezoelectric properties of Ba1−1.5xYxTiO3 (x = 0–0.03) is investigated. The samples are synthesized using solid‐state route (SSR). The synthesized materials are analyzed by X‐ray diffraction (XRD), which indicated the formation of crystalline materials exhibiting tetragonal phase. The samples with composition x = 0.005 and 0.01 are denser relative to other samples. The dielectric constant and loss tangent are measured in the temperature range −30 to 250 °C for different frequencies. The dielectric constant increases upto x = 0.005 (7555 at 1 kHz) and decreases thereafter. The shifts in the transition temperature (Tc) are corroborated with differential scanning calorimetry (DSC) studies. The electron paramagnetic resonance (EPR) data reveals that yttrium occupied Ti‐site after a certain limit of dissolution at Ba‐site. Modified Curie‐Weiss law was employed to study the extent of diffusivity. The effects of Y doping on morphology are investigated using scanning electron microscopy. The maximum remanence value (2Pr) and piezoelectric coefficient (d33) are 8.178 μC cm−2 and 116 pC/N respectively for x = 0.005 doping composition. A correlated behavior of optimum values is observed in density, dielectric constant, and piezoelectric coefficient which can be exploited for various applications.
Robust adaptive boundary control of semilinear PDE systems using a dyadic controller
Authors: Paranjape Aditya A. , Chung Soon‐Jo
Published: March 2018

In this paper, we describe a dyadic adaptive control framework for output tracking in a class of semilinear systems of partial differential equations with boundary actuation and unknown distributed nonlinearities. The dyadic adaptive control framework uses the linear terms in the system to split the plant into 2 virtual subsystems, one of which contains the nonlinearities, whereas the other contains the control input. Full‐plant‐state feedback is used to estimate the unmeasured individual states of the 2 subsystems as well as the nonlinearities. The control signal is designed to ensure that the controlled subsystem tracks a suitably modified reference signal. We prove the well posedness of the closed‐loop system rigorously and derive conditions for closed‐loop stability and robustness using finite‐gain
stability theory.
Formic Acid Synthesis by CO2 Hydrogenation over Single‐Atom Catalysts Based on Ru and Cu Embedded in Graphene
Authors: Sredojević Dušan N. , Šljivančanin Željko , Brothers Edward N. , Belić Milivoj R.
Published: March 2018

At variance with conventional heterogeneous catalysts, where only a small number of transition or noble metal atoms at surfaces play the role of active sites, in the single‐atom catalysts (SAC) each metal atom is involved in the catalytic process. Starting from isolated Ru and Cu atoms embedded on defects in graphene, denoted as Ru‐dG and Cu‐dG, we apply density functional theory (DFT) to examine utilizing these structures to catalyze the conversion of CO2 into the formic acid (FA). Our atomistic modeling of this reaction, highly relevant for reducing the CO2 level in the atmosphere, includes three different reaction pathways. The first relies on a direct hydrogenation of CO2 with protons from the H2 molecule. Due to energy barriers higher than 35 kcal/mol on both Ru‐dG and Cu‐dG, this reaction path does not represent a favorable route for FA synthesis. The other two reaction mechanisms start with the dissociative adsorption of H2 and then proceed via completely different paths. At Ru‐dG the CO2 hydrogenation occurs with the H atoms from the dissociated H2, while the Cu‐dG favors the proton transfer from an additional H2, coadsorbed with CO2 on hydrogenated SAC. Since we find that these pathways were accompanied with the activation energies smaller than 20 kcal/mol, our DFT study indicates that the Ru adatoms embedded into the defected graphene are promising candidates for designing a SAC enabling an efficient conversion of CO2 to FA. Since adsorbed H species markedly decrease Cu binding at the vacancy sites, the Cu‐dG is considerably less robust catalyst than Ru‐dG.
Creating and taming discord: How firms manage embedded competition in alliance portfolios to limit alliance termination
Authors: Asgari Navid , Tandon Vivek , Singh Kulwant , Mitchell Will
Published: March 2018

Research Summary: Firms with resources that make them attractive allies are also desirable partners for competitors so that competition among partners is embedded in alliance portfolios. We develop a framework in which competition within a portfolio creates benefits for a focal firm but threatens partners, increasing the hazard of alliance termination. We then propose four mechanisms for managing the threat of competition to partners reflecting aspects of portfolio configuration: alliance governance, social cohesion, social structure of competition, and partner similarity. We test our framework using a sample of 204 biopharmaceutical firms with alliance portfolios comprising 1,621 alliances between 1990 and 2000. The study addresses the interplay of competition and cooperation in alliance portfolios, and more generally, key aspects of value chain integration strategy.

Managerial Summary: Alliance portfolios comprise a focal firm's set of direct partners, some of which compete with each other because of overlapping resources, capabilities, and strategies. The threat of actual or perceived competition from other partners may cause some firms to terminate their alliance with the focal firm. We develop a framework comprising four mechanisms related to alliance portfolios—alliance governance, social cohesion, social structure of competition, and partner similarity—that allows focal firms to attenuate the hazard of termination of their alliances. We find support for our framework in a study of 204 biopharmaceutical firms with alliance portfolios comprising 1,621 alliances between 1990 and 2000. We improve understanding of how firms can manage competition and cooperation within their alliance portfolios.
Comparison of Microstructure and Tensile Properties of Dual Phase Steel Welded Using Friction Stir Welding and Gas Tungsten Arc Welding
Authors: Ashrafi Hamid , Shamanian Morteza , Emadi Rahmatollah , Ahl Sarmadi Mohammad
Published: March 2018

In the present research, a comparative study on influence of friction stir welding (FSW) and gas tungsten arc welding (GTAW) processes on the microstructure and tensile properties of dual phase steel welds is carried out. The results indicate that the microstructure of weld metal and inner part of the heat affected zone (HAZ) in the GTA welded sample is composed of coarse bainite, Widmanestatten ferrite and ferrite–carbide (FC) aggregate. The sample welded by FSW exhibits the formation of fine ferrite, FC aggregate, and bainite in the weld nugget and inner part of the HAZ. Microhardness measurements reveal the formation of a softened zone in the subcritical area of the HAZ due to the tempering of the pre‐existing martensite. Both joints show lower tensile strength, tensile elongation and work hardening exponent compared to the base metal (BM), and fail in the softened HAZ during the uniaxial tensile test. However, the joint efficiency, work hardening rate and work hardening exponent of the sample welded by FSW are superior to those for the GTA welded sample. The predominant fracture mechanism for all samples is ductile with dimples on the fractured surfaces.
Model for Phosphorus Removal in LD Converter and Design of a Valuable Operative Practice
Authors: Mombelli Davide , Mapelli Carlo , Barella Silvia , Gruttadauria Andrea , Sosio Roberto , Valentino Giovanni , Ancona Vito
Published: March 2018

In the primary ironmaking production process, the use of iron ores featured by a high concentration of phosphorus leads to a greater difficulty to manage the refining period of the hot metal by the Basic Oxygen Furnace. Recently, the phosphorus concentration in the hot metal can reach 0.08–0.11 wt% resulting in operative practice troubles for achieving a final P concentration lower than 0.015 wt%. In this study, a kinetic‐thermodynamic model for dephosphorization is proposed and a more efficient dephosphorization procedure of the hot metal in LD converters (350 t) have been developed. The model is a valuable tool to predict the dephosphorization evolution and allows the implementation of a new blowing pattern, able to reach a final P concentration at the end‐point lower than the threshold value of 0.015 wt% with only a slightly increase in lime (+10%) and oxygen consumption (+3%).
Modeling and Simulation of Dynamic Recrystallization Behavior in Alloyed Steel 15V38 during Hot Rolling
Authors: Wang Xin , Chandrashekhara K. , Lekakh Simon N. , Van Aken David C. , O'Malley Ronald J.
Published: March 2018

Dynamic recrystallization (DRX) occurring during hot rolling significantly affects the microstructural evolution and final mechanical properties of steel. In this study, single hot compression tests are performed at temperatures between 1000 and 1300 °C with strain rates between 0.01 and 15 s−1 to investigate dynamic recrystallization behavior of a 15V38 steel. Critical strains for initiation of dynamic recrystallization and peak strains are identified through the analysis of work hardening rate from the measured stress–strain results. Dynamic recrystallization is identified by the softening in the flow stress during plastic deformation and quantified as the difference between a calculated dynamic recovery curve and the measured stress–strain curve. Dynamic recrystallization is modeled using calculated critical strain, peak strain, Zener‐Hollomon (Z) parameter, and volume fraction of dynamic recrystallization. Subroutines accounting for dynamic recrystallization are developed and implemented into a three‐dimensional finite element model for hot rolling of a round bar. Simulation results show that dynamic recrystallization is distributed throughout the bar and exhibits a positive relationship with equivalent plastic strain. Temperature effects on dynamic recrystallization are also investigated using different rolling temperatures, and results show that the fraction of dynamic recrystallization is significantly increased as rolling temperature increases.
The Changes in Structural, Physicochemical, and Digestive Properties of Red Adzuki Bean Starch after Repeated and Continuous Annealing Treatments
Authors: Xu Meijuan , Saleh Ahmed S.M. , Liu Yu , Jing Luzhen , Zhao Kun , Wu Hao , Zhang Guoquan , Yang Shaohui O. , Li Wenhao
Published: March 2018

Red adzuki bean starch‐water suspensions (1:3, w/v) are subjected to repeated and continuous annealing treatments at 55 °C for 96 h. The changes in structural, physicochemical, and digestive properties of starch after both treatments are studied and compared. The results show that the repeated and continuous annealing increases the relative crystallinity of starch without influencing the morphological structure and crystalline patterns. Gelatinization temperatures and enthalpy increase; however starch solubility, swelling power, and viscosity decrease after both annealing treatments. FT‐IR analysis shows that annealing treatments result in a reorganization of starch molecules and improve the crystalline perfection. Furthermore, the applied annealing treatments decrease the enzymatic susceptibility of starch and increase the percentage of slowly digestible and resistant starch present. Generally, the repeated annealing results in modified starch with good functionalities compared with continuous annealing. Therefore, repeated annealing can be recommended for producing of modified starch for industrial applications.