bluuebunny/crossref_metadata_2025_split huggingface dataset:
Formal [3 + 2] cycloaddition of azomethine ylides generated in situ with unactivated cyclic imines: A facile approach to tricyclic imidazolines derivatives
Authors: Wang Kai‐Kai , Li Yan‐Li , Wang Zhan‐Yong , Ma Xueji , Mei Ya‐Lei , Zhang Shan‐Shan , Chen Rongxiang 
Published: December 2019

AbstractA simple and efficient method for the synthesis of tricyclic imidazolines derivatives via [3 + 2] 1,3‐dipolar cycloaddition between nonstabilized azomethine ylide generated in situ with unactivated cyclic imines is reported here. The method provided easy and mild access to various fused tricyclic hexahydroimidazo[5,1‐a]isoquinolines in excellent yields (up to 96%). This protocol is simple and easy to handle.
Comparison of the pH‐dependent formation of His and Cys heptapeptide complexes of nickel(II), copper(II), and zinc(II) as determined by ion mobility‐mass spectrometry
Authors: Yousef Enas N. , Angel Laurence A. 
Published: December 2019

AbstractThe analog methanobactin (amb) peptide with the sequence ac‐His1‐Cys2‐Gly3‐Pro4‐Tyr5‐His6‐Cys7 (amb5A) will bind the metal ions of zinc, nickel, and copper. To further understand how amb5A binds these metals, we have undertaken a series of studies of structurally related heptapeptides where one or two of the potential His or Cys binding sites have been replaced by Gly, or the C‐terminus has been blocked by amidation. The studies were designed to compare how these metals bind to these sequences in different pH solutions of pH 4.2 to 10 and utilized native electrospray ionization (ESI) with ion mobility‐mass spectrometry (IM‐MS) which allows for the quantitative analysis of the charged species produced during the reactions. The native ESI conditions were chosen to conserve as much of the solution‐phase behavior of the amb peptides as possible and an analysis of how the IM‐MS results compare with the expected solution‐phase behavior is discussed. The oligopeptides studied here have applications for tag‐based protein purification methods, as therapeutics for diseases caused by elevated metal ion levels or as inhibitors for metal‐protein enzymes such as matrix metalloproteinases.
Wide QRS complex and the risk of major arrhythmic events in Brugada syndrome patients: A systematic review and meta‐analysis
Authors: Rattanawong Pattara , Kewcharoen Jakrin , Techorueangwiwat Chol , Kanitsoraphan Chanavuth , Mekritthikrai Raktham , Prasitlumkum Narut , Puttapiban Prapaipan , Mekraksakit Poemlarp , Vutthikraivit Wasawat , Sorajja Dan 
Published: December 2019

AbstractBackgroundBrugada syndrome (BrS) is an inherited arrhythmic disease associated with an increased risk of major arrhythmic events (MAE). Previous studies reported that a wide QRS complex may be useful as a predictor of MAE in BrS patients. We aimed to assess the correlation of wide QRS complex with MAE by a systematic review and meta‐analysis.MethodsWe comprehensively searched the databases of MEDLINE and EMBASE from inception to June 2019. Included studies were cohort and case control studies that reported QRS duration and the relationship between wide QRS complex (>120 milliseconds) and MAE (sudden cardiac death, sudden cardiac arrest, ventricular fibrillation, sustained ventricular tachycardia, or appropriate shock). Data from each study were combined using the random‐effects model.ResultsTwenty‐two studies from 2007 to 2018 were included in this meta‐analysis involving 4,814 BrS patients. The mean age was 46.1 ± 12.8 years. The patients were predominately men (77.6%). Wide QRS duration was an independent predictor of MAE (pooled risk ratio 1.55, 95% confidence interval: 1.04‐2.30, P = .30, I2 = 38.4%). QRS duration was wider in BrS who had history of MAE (weight mean difference = 8.12 milliseconds, 95% confidence interval: 5.75‐10.51 milliseconds).ConclusionsOur study demonstrated that QRS duration is wider in BrS who had history of MAE, and a wide QRS complex is associated with 1.55 times higher risk of MAE in BrS populations. Wide QRS complex can be considered for risk stratification in prediction of MAE in patients with BrS, especially when considering implantable cardioverter‐defibrillator placement in asymptomatic patients.
Audience perceptions of high‐status ties and network advantage: The market for coaching jobs in the National Collegiate Athletic Association (2000–2011)
Authors: Halgin Daniel S. , Borgatti Stephen P. , Mehra Ajay , Soltis Scott 
Published: December 2019

SummarySocial ties with high‐status others can be a potent signal of an individual's underlying quality and future promise. Individuals in competitive markets, therefore, have an incentive to publicly claim connections to high‐status others. However, cognitive limitations and biases can make social network connections difficult for observers to reliably discern, and claims to high‐status ties can go unrecognized by the audience. Our core contention is that claims to high‐status affiliation are advantageous only when the audience recognizes the claim—unrecognized claims, like unreliable signals, do not deliver advantage and can backfire. Further, we draw on the literature on imprinting and develop arguments for why some people are more likely to make claims to high‐status ties and why some claims to high‐status ties are more likely than others to be recognized by the audience. We test our arguments with data from the market for head coaching jobs in NCAA basketball (2000–2011). Our study contributes to the sparse literature on how social network ties that exist in the minds of third‐party observers influence individual attainment in market settings; and it offers new insights into how imprinting processes shape the perception and use of high‐status network ties.
Development and validation of a nomogram for predicting overall survival of node‐negative ampullary carcinoma
Authors: Huang Xi‐Tai , Huang Chen‐Song , Chen Wei , Cai Jian‐Peng , Gan Tian‐Tian , Zhao Ying , Liu Qi , Liang Li‐Jian , Yin Xiao‐Yu 
Published: December 2019

AbstractBackgroundThe accuracy of the current staging system for predicting the overall survival (OS) of patients with ampullary carcinoma (AC) is still unsatisfactory, especially in node‐negative (N0) patients. We aimed at establishing a nomogram to accurately predict OS in N0 AC.MethodSThis study enrolled 697 N0 AC patients from the Surveillance, Epidemiology, and End Results database (design cohort [DC], n = 697) and the First Affiliated Hospital of Sun Yat‐sen University (validation cohort [VC], n = 112), who underwent surgical resection. The nomogram was established by using prognostic factors determined by univariate and multivariate regression analyses.ResultsThe nomogram for OS was developed by using four independent prognostic factors, including age, grade, T stage, and a number of examined lymph nodes. The C‐index of a nomogram for OS in DC and VC was 0.665 and 0.731, respectively. Calibration curves showed good consistency of the nomogram. The nomogram had a better accuracy in predicting OS compared with conventional staging system (P < .05). On the basis of nomogram‐predicted scores, the patients were stratified into groups with different risk. The OS of low‐risk patients was significantly longer than high‐risk ones (P ≤ .010).ConclusionsThe nomogram could be used to predict the OS of N0 AC. It could help guide further treatment in clinical practice.
miR‐574‐3p inhibits proliferation and invasion in esophageal cancer by targeting FAM3C and MAPK1
Authors: Jin Ling‐Li , Zhang Shao‐Jun , Lu Guang‐Xin , Lv Fei , Shang Rui , Yang Jie 
Published: December 2019

AbstractEsophageal cancer is considered as one of the leading malignancies. MicroRNA‐574‐3p (miR‐574‐3p) was used as a postoperative prognostic indicator in patients with esophageal squamous cell carcinoma. However, the underlying mechanism miR‐574‐3p involvement in esophageal cancer remains unclear. In this study, the expression of miR‐574‐3p was reduced in esophageal cancer tissues and cells. In vitro, miR‐574‐3p mimics and inhibitor were transfected into esophageal cancer cells (TE‐1 and TE‐8 cells) to up‐ or downregulating of miR‐574‐3p. miR‐574‐3p inhibited proliferation, migration and invasion, and promoted apoptosis in esophageal cancer cells. In addition, miR‐574‐3p was confirmed to target family with sequence similarity 3 member C (FAM3C) and mitogen‐activated protein kinase 1 (MAPK1). miR‐574‐3p suppressed phosphoinositide 3‐kinase (PI3K)/protein kinase B (AKT) and rapidly accelerated fibrosarcoma (Raf)/mitogen‐activated protein kinase (MEK)/extracellular signal‐regulated kinase (ERK) signaling via regulating FAM3C and MAPK1. In vivo, overexpression of miR‐574‐3p suppressed tumor growth in mice. Our findings indicated that miR‐574‐3p repressed proliferation and invasion of esophageal cancer via regulation of FAM3C and MAPK1, which provides a new biomarker for esophageal cancer treatment.
Dynamic Contributions to the Bulk Mechanical Properties of Self‐Assembled Polymer Networks with Reconfigurable Bonds
Authors: Tang Xiaomin , Wang Bingqing , Eristoff Sophia , Zhang Han , Bettinger Christopher J. 
Published: December 2019

AbstractSoft materials that contain dynamic and reversible bonds exhibit unique properties including unusual extensibility, reversible elasticity, and self‐healing capabilities, for example. Catechol motifs are of particular interest owing to their ability to form many kinds of reversible bonds; however, there are few reports on the role of hydrogen bonds between catechols. Here, physically crosslinked self‐assembled networks composed of catechol‐functionalized ABA triblock co‐polymers are synthesized and characterized to elucidate the role of intermolecular bonding between catechol motifs on bulk mechanical properties. The Young's moduli of equilibrated networks range from 16 to 43 MPa. Furthermore, the concentration of intermolecular interaction is controlled indirectly by synthesizing polymers with prescribed catechol concentrations on each A block. Further, network dynamics are characterized by measuring the relaxation spectrum, and it is found that the network mean relaxation time is inversely related to catechol density. Finally, networks exhibit time‐dependent recovery after uniaxial strain. These findings establish important relationships between molecular design, network composition, and macroscopic mechanical properties of model soft matter networks with dynamic intermolecular bonds. Furthermore, this insight has the potential to guide the design of dissipative materials for use in applications ranging from consumer products to surgical materials.
Temperature sensing scheme based on fiber ring microwave photonic filter with erbium doped fiber amplification
Authors: Yang Shangwu , Xiang Zhuowei , Fu Hongyan , Wang Yunfeng 
Published: December 2019

AbstractThe temperature sensing scheme based on fiber ring microwave photonic filter (MPF) with erbium doped fiber amplification (EDFA) is proposed and experimentally demonstrated. The fiber ring is used as the time delay element, as well as a sensing element, and by introducing an EDFA to compensate the loss in the fiber ring, the number of the effective sampling taps and thus the suppression ratio are increased. When the EDFA power is set at 0.74 mW, the 3 dB bandwidth of the passband and suppression ratio of the MPF are estimated to be 82.5 kHz, and 15 dB, respectively. The superior sharp passband characteristics make the fiber ring MPF with an EDFA very advantageous for sensing. In our experiment, temperature sensing by using the fiber ring MPF with an EDFA has been carried out for demonstration. The temperature variations induce refractive index changes of the fiber, which will change the time delay of each tap of the fiber ring MPF, and as a result, the FSR of the MPF will be changed. By tracing the peak point shift of the MPF's passband, the temperature variations can be monitored. Our experimental results show that there is a good linear relationship between temperature change and frequency shift, and by measuring passbands with different frequencies, different sensitivity can be obtained. In our experiment, the sensitivity is estimated to be −5.89, −11.74, and − 17.7 kHz/°C, respectively, when the passbands at 0.8, 1.6, and 2.4 GHz are adopted for temperature monitoring.
A compact broadband differential‐fed microstrip patch antenna with 5.8 GHz WLAN band‐notched under quad‐mode resonance
Authors: Feng Shu , Zhang Li , Weng Zi‐Bin , Jiao Yong‐Chang 
Published: December 2019

AbstractA compact broadband differential‐fed microstrip patch antenna with 5.8 GHz WLAN band‐notched under quad‐mode resonance is proposed in this article. The antenna consists of two hybrid shape radiation patches and a pair of capacitances loaded loop (CLL) resonators. The broadband performance is achieved by integrating TM10 and TM01 radiation modes of rectangular patches and TM1,0,−1 radiation mode of triangular patches. Then these three radiation modes are adjusted close to each other to form a wide operation band. After that, with the loading of CLL resonators, a nonradiative resonant mode is introduced. Thus, the low‐frequency band of the proposed antenna can be further expanded, and a frequency notch point is introduced in 5.8 GHz WLAN band. Finally, the proposed antenna is fabricated and measured. The measured impedance bandwidth is about 43.5% (5.93‐9.23 GHz) while keeping a compact structure without any air gaps. Additionally, the broadside gain is varied from 4 to 6 dBi with a notch point at 5.8 GHz.
A Ku band frequency‐reconfigurable dielectric resonator antenna using metallic pillars
Authors: Tong Chang‐Wu , Tang Hui , Qin Wei , Yang Wen‐Wen , Chen Jian‐Xin 
Published: December 2019

AbstractA Ku band frequency‐reconfigurable dielectric resonator antenna (DRA) using metallic pillars is presented in this letter. A novel frequency tuning method of the DRA is proposed by selectively loading metallic pillars at two narrow sides of the DRA. Resonating at its fundamental mode, the operating frequency of the DRA can be continuously controlled by changing the heights of the pillars in a large frequency tuning range. In the range, the DRA remains good impedance match, stable radiation patterns, and low cross‐polarization level. To verify the proposed method, a prototype operated at Ku band is designed, fabricated and measured. A measured frequency tuning range of 33% with gain higher than 5.3 dBi and cross‐polarization level less than −20 dB are achieved within the range, showcasing reasonable agreement with the simulated results.
Review of air kerma‐area product, effective dose and dose conversion coefficients for non‐cardiac interventional fluoroscopy procedures
Authors: Miller Donald L. 
Published: December 2019

PurposeTo provide current data on average air kerma‐area product (PKA) and effective dose (E) for noncardiac interventional fluoroscopy procedures and suggested values of dose coefficients (DCE) for conversion of PKA to estimates of effective dose.MethodsA PubMed literature search covering the time period from 2006 to August 2019 was performed to obtain recent data on PKA, E and DCE for interventional fluoroscopy procedures.ResultsThere is very wide variation in the reported values of PKA, E, and DCE in the literature. A number of factors are involved in this variability and the resultant uncertainty in average values of these dose quantities.ConclusionsThe values of PKA, average E and suggested DCE presented here can be of use for comparison of the radiation detriment from different procedures and may be useful for categorizing detriment within an order of magnitude or so. They do not represent actual or expected radiation dose or detriment from any specific procedure or for a specific patient and should be not be used as such.
Virtual 4DCT from 4DMRI for the management of respiratory motion in carbon ion therapy of abdominal tumors
Authors: Meschini Giorgia , Vai Alessandro , Paganelli Chiara , Molinelli Silvia , Fontana Giulia , Pella Andrea , Preda Lorenzo , Vitolo Viviana , Valvo Francesca , Ciocca Mario , Riboldi Marco , Baroni Guido 
Published: December 2019

PurposeTo evaluate a method for generating virtual four‐dimensional computed tomography (4DCT) from four‐dimensional magnetic resonance imaging (4DMRI) data in carbon ion radiotherapy with pencil beam scanning for abdominal tumors.MethodsDeformable image registration is used to: (a) register each respiratory phase of the 4DMRI to the end‐exhale MRI; (b) register the reference end‐exhale CT to the end‐exhale MRI volume; (c) generate the virtual 4DCT by warping the registered CT according to the obtained deformation fields. A respiratory‐gated carbon ion treatment plan is optimized on the planning 4DCT and the corresponding dose distribution is recalculated on the virtual 4DCT. The method was validated on a digital anthropomorphic phantom and tested on eight patients (18 acquisitions). For the phantom, a ground truth dataset was available to assess the method performances from the geometrical and dosimetric standpoints. For the patients, the virtual 4DCT was compared with the planning 4DCT.ResultsIn the phantom, the method exhibits a geometrical accuracy within the voxel size and Dose Volume Histograms deviations up to 3.3% for target V95% (mean dose difference ≤ 0.2% of the prescription dose, gamma pass rate > 98%). For patients, the virtual and the planning 4DCTs show good agreement at end‐exhale (3% median D95% difference), whereas other respiratory phases exhibit moderate motion variability with consequent dose discrepancies, confirming the need for motion mitigation strategies during treatment.ConclusionsThe virtual 4DCT approach is feasible to evaluate treatment plan robustness against intra‐ and interfraction motion in carbon ion therapy delivered at the abdominal site.
Solid state nuclear magnetic resonance studies of hydroxypropylmethylcellulose acetyl succinate polymer, a useful carrier in pharmaceutical solid dispersions
Authors: Pugliese Andrea , Hawarden Lucy E. , Abraham Anuji , Tobyn Michael , Blanc Frédéric 
Published: December 2019

AbstractHydroxypropylmethylcellulose (HPMC) acetyl succinate (HPMC‐AS) is a key polymer used for the enablement of amorphous solid dispersions (ASDs) in oral solid dosage forms. Choice of the appropriate grade within the material is often made empirically by the manufacturer of small‐scale formulations, followed by extensive real time stability. A key factor in understanding and predicting the performance of an ASD is related to the presence of hydrogen (or other) bonds between the polymer and active pharmaceutical ingredient (API), which will increase stability over the parameters captured by miscibility and predicted by the Gordon–Taylor equation. Solid state nuclear magnetic resonance (NMR) is particularly well equipped to probe spatial proximities, for example, between polymer and API; however, in the case of HPMC‐AS, these interactions have been sometimes difficult to identity as the carbon‐13 NMR spectra assignment is yet to be firmly established. Using feedstock, selectively substituted HPMC polymers, and NMR editing experiments, we propose here a comprehensive understanding of the chemical structure of HPMC‐AS and a definitive spectral assignment of the13C NMR spectra of this polymer. The NMR data also capture the molar ratios of the acetate and succinate moieties present in HPMC‐AS of various grades without the need for post treatment required by chromatography methods commonly use in pharmacopoeia. This knowledge will allow the prediction and measurement of interactions between polymers and APIs and therefore a rational choice of polymer grade to enhance the solid state stability of ASDs.
A molecular fluorophore in citric acid/ethylenediamine carbon dots identified and quantified by multinuclear solid‐state nuclear magnetic resonance
Authors: Duan Pu , Zhi Bo , Coburn Luke , Haynes Christy L. , Schmidt‐Rohr Klaus 
Published: December 2019

AbstractThe composition of fluorescent polymer nanoparticles, commonly referred to as carbon dots, synthesized by microwave‐assisted reaction of citric acid and ethylenediamine was investigated by 13C, 13C{1H}, 1H─13C, 13C{14N}, and 15N solid‐state nuclear magnetic resonance (NMR) experiments. 13C NMR with spectral editing provided no evidence for significant condensed aromatic or diamondoid carbon phases. 15N NMR showed that the nanoparticle matrix has been polymerized by amide and some imide formation. Five small, resolved 13C NMR peaks, including an unusual ═CH signal at 84 ppm (1H chemical shift of 5.8 ppm) and ═CN2 at 155 ppm, and two distinctive 15N NMR resonances near 80 and 160 ppm proved the presence of 5‐oxo‐1,2,3,5‐tetrahydroimidazo[1,2‐a]pyridine‐7‐carboxylic acid (IPCA) or its derivatives. This molecular fluorophore with conjugated double bonds, formed by a double cyclization reaction of citric acid and ethylenediamine as first shown by Y. Song, B. Yang, and coworkers in 2015, accounts for the fluorescence of the carbon dots. Cross‐peaks in a 1H─13C HETCOR spectrum with brief 1H spin diffusion proved that IPCA is finely dispersed in the polyamide matrix. From quantitative 13C and 15N NMR spectra, a high concentration (18 ± 2 wt%) of IPCA in the carbon dots was determined. A pronounced gradient in 13C chemical‐shift perturbations and peak widths, with the broadest lines near the COO group of IPCA, indicated at least partial transformation of the carboxylic acid of IPCA by amide or ester formation.
Norwegian PhD students' discourses about practice‐relevant research in the field of health and social work
Authors: Kristoffersen Margareth , Vagli Åse , Oftedal Bjørg Frøysland 
Published: December 2019

AbstractAimThe aim of this study was to explore the discourses of PhD students concerning the performance of practice‐relevant research in health and social work.DesignAn explorative, qualitative design and a discourse analytical approach were used to collect data.MethodsParticipants were recruited from a national research school for practice‐relevant research in Norway. Group interviews with ten PhD students (five health and five social work professionals) with extensive, wide‐ranging work experience as practitioners were used to collect data. The data were analysed by discourse analysis.ResultsThe analysis revealed three discourses: (a) the professional knowledge discourse; (b) the promoting partnership discourse; and (c) the using research knowledge discourse. The discourses are explicit concerning how systematically formed practice‐relevant research in health and social work is linked to dominant discourses about knowledge in the scientific field. Professional knowledge, promoting partnership and using research knowledge are fundamental features of practice‐relevant research.