bluuebunny/crossref_metadata_2025_split huggingface dataset:
Energy Transfer in Supramolecular Heteronuclear Lanthanide Dimers and Application to Fluoride Sensing in Water
Authors: Nonat Aline , Liu Tao , Jeannin Olivier , Camerel Franck , Charbonnière Loïc J. 
Published: January 2018

AbstractIn the presence of fluoride anions, [LnL(H2O)]+ complexes, based on the coordination of a lanthanide (Ln) cation into the cavity of a C2v symmetrical cyclen‐based ligand (L), self‐assemble in water to form [(LnL)2F]+ dimers. The crystal structures of the Yb hydrated monomer and of the fluorinated dimer are reported and analyzed to unravel the impact of the cumulative effect of weak hydrogen bonding and aromatic stacking interactions in the supramolecular assembly. The assembly is stable over a broad range of pH 3–8. A combination of equimolar amounts of Eu and Tb complexes led to a quasistatistical mixture of homo‐ and heterodimers, as observed by using electrospray mass spectrometry. In the heterodimers, selective excitation into the 7F6→5D4 absorption band of the Tb center at λ=488 nm allowed the observation of a Tb‐to‐Eu downshifting energy transfer, not observed in the absence of fluoride ions. Analysis of the excited‐state lifetimes of the dimers within the frame of the Förster theory of energy transfer showed the transfer to have an efficiency of 34 %, with a corresponding Förster radius of 4.1 Å; thereby, unraveling the short Ln–Ln distance as a crucial parameter of the energy‐transfer process. By using equimolar mixtures of the Tb and Eu complexes, the energy‐transfer phenomenon was used for a ratiometric sensing of fluoride anions in water with a detection limit of 17.7 nm.
A “Signal On” Photoelectrochemical Biosensor Based on Bismuth@N,O‐Codoped‐Carbon Core–Shell Nanohybrids for Ultrasensitive Detection of Telomerase in HeLa Cells
Authors: Liu Shanshan , Zhao Shulin , Tu Wenwen , Wang Xiaoying , Wang Xiao , Bao Jianchun , Wang Yu , Han Min , Dai Zhihui 
Published: January 2018

AbstractInvited for the cover of this issue is the group of Min Han and Zhihui Dai at the Nanjing Normal University. Read the full text of the article at 10.1002/chem.201704251.
In Silico Studies Designed to Select Sesquiterpene Lactones with Potential Antichagasic Activity from an In‐House Asteraceae Database
Authors: Acevedo Chonny Herrera , Scotti Luciana , Scotti Marcus Tullius 
Published: January 2018

AbstractChagas disease is an endemic disease caused by Trypanosoma cruzi, which affects more than eight million people, mostly in the Americas. A search for new treatments is necessary to control and eliminate this disease. Sesquiterpene lactones (SLs) are an interesting group of secondary metabolites characteristic of the Asteraceae family that have presented a wide range of biological activities. From the ChEMBL database, we selected a diverse set of 4452, 1635, and 1322 structures with tested activity against the three T. cruzi parasitic forms: amastigote, trypomastigote, and epimastigote, respectively, to create random forest (RF) models with an accuracy of greater than 74 % for cross‐validation and test sets. Afterward, a ligand‐based virtual screen of the entire SLs of the Asteraceae database stored in SistematX (1306 structures) was performed. In addition, a structure‐based virtual screen was also performed for the same set of SLs using molecular docking. Finally, using an approach combining ligand‐based and structure‐based virtual screening along with the equations proposed in this study to normalize the probability scores, we verified potentially active compounds and established a possible mechanism of action.
A comprehensive analysis of neurotrophins and neurotrophin tyrosine kinase receptors expression during development of zebrafish
Authors: Nittoli Valeria , Sepe Rosa M. , Coppola Ugo , D'Agostino Ylenia , De Felice Elena , Palladino Antonio , Vassalli Quirino A. , Locascio Annamaria , Ristoratore Filomena , Spagnuolo Antonietta , D'Aniello Salvatore , Sordino Paolo 
Published: January 2018

AbstractNeurotrophins (NTF) are a family of secreted nerve growth factors with affinity for tyrosine kinase (Ntrk) and p75 receptors. To fully understand the variety of developmental roles played by NTFs, it is critical to know when and where genes encoding individual ligands and receptors are transcribed. Identification of ntf and ntrk transcripts in zebrafish development remains to be fully characterized for further uncovering the potential function(s) of the NTF signal transduction pathway. Here, we conducted a systematic analysis of the expression profiles of four ntf and five ntrk genes during zebrafish development using whole‐mount in situ hybridization. Our study unveils new expression domains in the developing embryo, confirms those previously known, and shows that ntf and ntrk genes have different degrees of cell‐ and tissue‐type specificity. The unique and overlapping expression patterns here depicted indicate the coordination of the redundant and divergent functions of NTFs and represent valuable tools for deciphering the molecular pathways involved in the specification and function of embryonic cell types.
Eye‐specific segregation and differential fasciculation of developing retinal ganglion cell axons in the mouse visual pathway
Authors: Sitko Austen A. , Kuwajima Takaaki , Mason Carol A. 
Published: January 2018

AbstractPrior to forming and refining synaptic connections, axons of projection neurons navigate long distances to their targets. While much is known about guidance cues for axon navigation through intermediate choice points, whether and how axons are organized within tracts is less clear. Here we analyze the organization of retinal ganglion cell (RGC) axons in the developing mouse retinogeniculate pathway. RGC axons are organized by both eye‐specificity and topography in the optic nerve and tract: ipsilateral RGC axons are segregated from contralateral axons and are offset laterally in the tract relative to contralateral axon topographic position. To identify potential cell‐autonomous factors contributing to the segregation of ipsilateral and contralateral RGC axons in the visual pathway, we assessed their fasciculation behavior in a retinal explant assay. Ipsilateral RGC neurites self‐fasciculate more than contralateral neurites in vitro and maintain this difference in the presence of extrinsic chiasm cues. To further probe the role of axon self‐association in circuit formation in vivo, we examined RGC axon organization and fasciculation in an EphB1−/− mutant, in which a subset of ipsilateral RGC axons aberrantly crosses the midline but targets the ipsilateral zone in the dorsal lateral geniculate nucleus on the opposite side. Aberrantly crossing axons retain their association with ipsilateral axons in the contralateral tract, indicating that cohort‐specific axon affinity is maintained independently of guidance signals present at the midline. Our results provide a comprehensive assessment of RGC axon organization in the retinogeniculate pathway and suggest that axon self‐association contributes to pre‐target axon organization.
Cognitive Characterization of Air‐Flow Stimulus
Authors: TAKAHASHI HARUKA , BANDO SHIZUKA , OIWA KOSUKE , NOZAWA AKIO , ISHIKAWA TOMOHARU , MITSUI MINORU 
Published: January 2018

SUMMARYExtra‐high‐quality audio devices, which are reproducible sound of broadband, have appeared in recent years. Such audio devices of broadband can feel like a deeper sense of realism as an air field by feeling the vibration of the air with entire body. This technology is expected application as sense of presentation technology. Using this technology, development of the new stimulus medium that is the field generating device, such as wrapped up in air is enabled. The purpose of this study is to create a completely new sense with the airflow stimulus termed “air sensation” by using the air field. In this study, we measured the psychophysical quantities to clarify the cognitive characterization of air sensation as a basic examination. Specifically, we measured the absolute thresholds to detect the air‐flow stimulus and sensitivity characteristics with respect to the strength of the stimulus. Consequently, it was revealed that cognitive characterizations vary with the properties of signal waveform, stimulus presentation site, and stimulus presentation order.
Electrochemical Aptasensor Based on Poly(Neutral Red) and Carboxylated Pillar[5]arene for Sensitive Determination of Aflatoxin M1
Authors: Smolko Vladimir , Shurpik Dmitry , Porfireva Anna , Evtugyn Gennady , Stoikov Ivan , Hianik Tibor 
Published: January 2018

AbstractAptasensor for highly sensitive determination of aflatoxin M1 (AFM1) was developed on the base of glassy carbon electrode (GCE) covered with polymeric Neutral red (NR) dye obtained by electropolymerization in the presence of polycarboxylated pillar[5]arene derivative. Aptamer against AFM1 and NR label were then covalently linked to the carboxylic groups of the carrier by carbodiimide binding. At presence of AFM1 the cathodic peak current related to the NR conversion decreases. AFM1 induced also an increase of the charge transfer resistance measured by electrochemical impedance spectroscopy. In optimal conditions, this make it possible to determine from 5 to 120 ng/L AFM1 in standard solutions with limit of detection (LOD) of 0.5 ng/L. The aptasensor was validated on the spiked samples of cow and sheep milk as well as in kefir after their methanol dilution. Reliable detection of the 40–160 ng/kg of mycotoxins was reached. This is below limited threshold value (50 μg/kg) established in EC.
A generalized focused information criterion for GMM
Authors: Chang Minsu , DiTraglia Francis J. 
Published: January 2018

SummaryThis paper proposes a criterion for simultaneous generalized method of moments model and moment selection: the generalized focused information criterion (GFIC). Rather than attempting to identify the “true” specification, the GFIC chooses from a set of potentially misspecified moment conditions and parameter restrictions to minimize the mean squared error (MSE) of a user‐specified target parameter. The intent of the GFIC is to formalize a situation common in applied practice. An applied researcher begins with a set of fairly weak “baseline” assumptions, assumed to be correct, and must decide whether to impose any of a number of stronger, more controversial “suspect” assumptions that yield parameter restrictions, additional moment conditions, or both. Provided that the baseline assumptions identify the model, we show how to construct an asymptotically unbiased estimator of the asymptotic MSE to select over these suspect assumptions: the GFIC. We go on to provide results for postselection inference and model averaging that can be applied both to the GFIC and various alternative selection criteria. To illustrate how our criterion can be used in practice, we specialize the GFIC to the problem of selecting over exogeneity assumptions and lag lengths in a dynamic panel model, and show that it performs well in simulations. We conclude by applying the GFIC to a dynamic panel data model for the price elasticity of cigarette demand.
Realized extreme quantile: A joint model for conditional quantiles and measures of volatility with EVT refinements
Authors: Bee Marco , Dupuis Debbie J. , Trapin Luca 
Published: January 2018

SummaryWe propose a new framework exploiting realized measures of volatility to estimate and forecast extreme quantiles. Our realized extreme quantile (REQ) combines quantile regression with extreme value theory and uses a measurement equation that relates the realized measure to the latent conditional quantile. Model estimation is performed by quasi maximum likelihood, and a simulation experiment validates this estimator in finite samples. An extensive empirical analysis shows that high‐frequency measures are particularly informative of the dynamic quantiles. Finally, an out‐of‐sample forecast analysis of quantile‐based risk measures confirms the merit of the REQ.
MAPK and NF‐κB signalling pathways regulate the expression of miRNA, let‐7f in human endocervical epithelial cells
Authors: Ayyar Kanchana K. , Reddy Kudumula V. R. 
Published: January 2018

AbstractMicroRNAs (miRNAs) mediate post‐transcriptional gene suppression and are a critical component of the complex regulatory networks in epithelial immune responses. Transcription of miRNA genes in epithelial cells can be elaborately controlled through Toll‐like receptors (TLRs), and associated nuclear factor kappa‐light‐chain‐enhancer of activated B cells (NF‐κB) and mitogen‐activated protein kinase (MAPK) pathways, leading to nuclear transcription factor associated‐transactivation and transrepression of miRNAs. MiRNA, let‐7f is involved in the regulation of innate immune responses post TLR3 stimulation in human endocervical cells (End1/E6E7) and decreased let‐7f is associated with poor immune activation. Thus, expression of let‐7f is under strict control. However, the mechanism by which let‐7f is regulated in these cells is not known. Therefore, in the present study, we have investigated the role of MAPK and NF‐κB in the transcription of let‐7f. We report that signalling of TLR3, results in activation of multiple signalling pathways including MAPK/ERK, JNK, p38, and NF‐κB. Of these MAPK/ p38 and JNK directly influence the expression of let‐7f in End1/E6E7 cells. Inhibition of ERK and NF‐κB up regulates the expression of let‐7f and its transcription factor, C/EBPβ. In conclusion, we have identified a system through which TLR3 mediated immune response is regulated by C/EBPβ and let‐7f through the temporal activation of MAPK and NF‐κB in human endocervical cells.
Discrimination, religious and cultural factors, and Middle Eastern/Arab Americans’ psychological distress
Authors: Ikizler Ayse S. , Szymanski Dawn M. 
Published: January 2018

AbstractObjective(s)We investigated (1) the moderating role of religiosity in the link between religious affiliation and ethnic discrimination and (2) the moderating roles of religiosity, ethnic identity, and family connectedness in the relations between ethnic discrimination and psychological distress.MethodOur sample consisted of 122 (60% women, 40% men) Middle Eastern/Arab Americans (MEAAs), ranging in age from 18 to 82 years old, who completed an online survey.ResultsMuslim identification predicted discrimination for MEAAs with high but not low religiosity. Higher levels of discrimination, more family connectedness, the interaction of discrimination and religiosity, and the interaction of discrimination and family connectedness were unique predictors of psychological distress.ConclusionsReligiosity is a risk factor for experiencing ethnic discrimination among Muslim identified MEAAs. MEAAs who have high religiosity and low to moderate levels of family connectedness are vulnerable to psychological distress associated with ethnic discrimination.
Patchy colitis, and young age at diagnosis and at the time of surgery predict subsequent development of Crohn's disease after ileal pouch‐anal anastomosis surgery for ulcerative colitis
Authors: Abel Alexandra G , Chung Alvin , Paul Eldho , Gibson Peter R , Sparrow Miles P 
Published: January 2018

Background and AimA proportion of patients having total proctocolectomy and ileal pouch‐anal anastomosis (IPAA) for ulcerative colitis (UC) are later diagnosed with Crohn's disease (CD). The aim of this study was to identify preoperative and perioperative predictors for the subsequent development of CD in patients who had IPAA for presumed UC.MethodsA retrospective case–control study of patients undergoing IPAA surgery for presumed UC was undertaken. Cases were patients who had a revised diagnosis of CD after surgery. Preoperative and perioperative variables were examined and analyzed.ResultsFifteen cases were compared with 39 controls. Patients aged ≤25 years at initial UC diagnosis were more likely to develop CD compared to those aged >25 years (odds ratio, OR [95% confidence interval, CI]: 7.1 [1.6–31.3]; P = 0.01). Patients aged ≤30 years at the time of colectomy had an increased risk of subsequent development of CD compared to those aged >30 years (OR [95% CI]: 4.5 [1.3–16.0]; P = 0.02). Cases were more likely to have patchy colitis on their colectomy specimen (OR [95% CI]: 6.7 [1.1–41.8]; P = 0.04). There was no significant difference between groups regarding transmural inflammation, ileitis, or fissuring ulcers on colectomy specimens, or preoperative C‐reactive protein (CRP), albumin, family history, and smoking status.ConclusionPredictors of the development of CD in the pouch include young age at diagnosis and at the time of surgery, and patchy colitis in the resected colon.
Computational chemical biology and drug design: Facilitating protein structure, function, and modulation studies
Authors: Zheng Mingyue , Zhao Jihui , Cui Chen , Fu Zunyun , Li Xutong , Liu Xiaohong , Ding Xiaoyu , Tan Xiaoqin , Li Fei , Luo Xiaomin , Chen Kaixian , Jiang Hualiang 
Published: January 2018

AbstractOver the past quarter of a century, there has been rapid development in structural biology, which now can provide solid evidence for understanding the functions of proteins. Concurrently, computational approaches with particular relevance to the chemical biology and drug design (CBDD) field have also incrementally and steadily improved. Today, these methods help elucidate detailed working mechanisms and accelerate the discovery of new chemical modulators of proteins. In recent years, integrating computational simulations and predictions with experimental validation has allowed for more effective explorations of the structure, function and modulation of important therapeutic targets. In this review, we summarize the main advancements in computational methodology development, which are then illustrated by several successful applications in CBDD. Finally, we conclude with a discussion of the current major challenges and future directions in the field.
Noise properties of proton density fat fraction estimated using chemical shift–encoded MRI
Authors: Roberts Nathan T. , Hernando Diego , Holmes James H. , Wiens Curtis N. , Reeder Scott B. 
Published: January 2018

PurposeThe purpose of this work is to characterize the noise distribution of proton density fat fraction (PDFF) measured using chemical shift–encoded MRI, and to provide alternative strategies to reduce bias in PDFF estimation.TheoryWe derived the probability density function for PDFF estimated using chemical shift–encoded MRI, and found it to exhibit an asymmetric noise distribution that contributes to signal‐to‐noise‐ratio dependent bias.MethodsTo study PDFF noise bias, we performed (at 1.5 T) numerical simulations, phantom acquisitions, and a retrospective in vivo experiment. In each experiment, we compared the performance of three statistics (mean, median, and maximum likelihood estimator) in estimating the PDFF in a region of interest.ResultsWe demonstrated the presence of the asymmetric noise distribution in simulations, phantoms, and in vivo. In each experiment we demonstrated that both the median and proposed maximum likelihood estimator statistics outperformed the mean statistic in mitigating noise‐related bias for low signal‐to‐noise‐ratio acquisitions.ConclusionsCharacterization of the noise distribution of PDFF estimated using chemical shift–encoded MRI enabled new strategies based on median and maximum likelihood estimator statistics to mitigate noise‐related bias for accurate PDFF measurement from a region of interest. Such strategies are important for quantitative chemical shift–encoded MRI applications that typically operate in low signal‐to‐noise‐ratio regimes. Magn Reson Med 80:685–695, 2018. © 2018 International Society for Magnetic Resonance in Medicine.
Development of methods and feasibility of using hyperpolarized carbon‐13 imaging data for evaluating brain metabolism in patient studies
Authors: Park Ilwoo , Larson Peder E.Z. , Gordon Jeremy W. , Carvajal Lucas , Chen Hsin‐Yu , Bok Robert , Van Criekinge Mark , Ferrone Marcus , Slater James B. , Xu Duan , Kurhanewicz John , Vigneron Daniel B. , Chang Susan , Nelson Sarah J. 
Published: January 2018

PurposeHyperpolarized carbon‐13 (13C) metabolic imaging is a noninvasive imaging modality for evaluating real‐time metabolism. The purpose of this study was to develop and implement experimental strategies for using [1‐13C]pyruvate to probe in vivo metabolism for patients with brain tumors and other neurological diseases.MethodsThe 13C radiofrequency coils and pulse sequences were tested in a phantom and were performed using a 3 Tesla whole‐body scanner. Samples of [1‐13C]pyruvate were polarized using a SPINlab system. Dynamic 13C data were acquired from 8 patients previously diagnosed with brain tumors, who had received treatment and were being followed with serial magnetic resonance scans.ResultsThe phantom studies produced good‐quality spectra with a reduction in signal intensity in the center attributed to the reception profiles of the 13C receive coils. Dynamic data obtained from a 3‐cm slice through a patient's brain following injection with [1‐13C]pyruvate showed the anticipated arrival of the agent, its conversion to lactate and bicarbonate, and subsequent reduction in signal intensity. A similar temporal pattern was observed in 2D dynamic patient studies, with signals corresponding to pyruvate, lactate, and bicarbonate being in normal appearing brain, but only pyruvate and lactate being detected in regions corresponding to the anatomical lesion. Physiological monitoring and follow‐up confirmed that there were no adverse events associated with the injection.ConclusionThis study has presented the first application of hyperpolarized 13C metabolic imaging in patients with brain tumor and demonstrated the safety and feasibility of using hyperpolarized [1‐13C]pyruvate to evaluate in vivo brain metabolism. Magn Reson Med 80:864–873, 2018. © 2018 International Society for Magnetic Resonance in Medicine.
Enteral Nutrition in the Management of Crohn's Disease: Reviewing Mechanisms of Actions and Highlighting Potential Venues for Enhancing the Efficacy
Authors: Alhagamhmad Moftah H. 
Published: January 2018

AbstractCrohn's disease (CD) is a chronic condition that affects the gut and has adverse effects on growth and development. There is a global increase in the incidence and prevalence rates, and several factors are believed to contribute to this rise, including dietary habits. In contrast, the use of enteral nutrition (EN) as an exclusive source of nutrition is increasingly becoming the preferred induction treatment of pediatric CD patients in part to address the nutrition complications. However, EN therapy is considered less effective in adults with CD. A better understanding of the molecular mechanisms of enteral therapy will help improve the clinical management of CD. It is increasingly becoming evident that the therapeutic utility of EN is in part due to the reversal of the microbial changes and the direct immunomodulatory effects. Moreover, there is a potential tendency for enhancing the efficacy of EN therapy by improving the palatability of the given formulas and, more important, by magnifying the anti‐inflammatory properties. Recent observations have shown that the immunomodulatory effects of EN are mediated at least in part by blocking nuclear factor‐κB. Furthermore, it is likely that several ingredients of EN contribute to this activity, in particular glutamine and arginine amino acids. In addition, manipulating the composition of EN therapy by altering concentrations of the key ingredients is found to have the potential for more efficient therapy. In this review, the underlying mechanisms of EN actions will be discussed further with a focus on the potential methods for enhancing the efficacy.