bluuebunny/crossref_metadata_2025 huggingface dataset:
Facile Deposition of Cu−SnOx Hybrid Nanostructures on Lightly Boron‐Doped Diamond Electrodes for CO2 Reduction
Authors: Roy Nitish , Suzuki Norihiro , Nakabayashi Yukihiro , Hirano Yuiri , Ikari Hiroshi , Katsumata Ken‐ichi , Nakata Kazuya , Fujishima Akira , Terashima Chiaki
Published: June 2018

In this work, we report a facile synthesis of Cu−SnOx hybrid nanostructures on lightly boron‐doped diamond (BDDL) electrodes by a potentiodynamic electrodeposition method. The deposition potential for Cu−SnOx hybrid nanostructures was cycled between 0 to −1.0 V vs Ag/AgCl for five consecutive runs at a scan rate of 50 mV/sec. The growth of the Cu−SnOx hybrid nanostructures on BDDL was optimized by varying the number of potentiodynamic deposition cycles and precursor concentration. A uniform particle size distribution of Cu−SnOx was obtained on BDDL using 10 mM CuSO4 and 5 mM SnCl2 in 50 mM aqueous NaNO3. Detail of surface morphology and surface elemental composition of the optimized Cu−SnOx hybrid nanostructures modified BDDL electrodes were characterized. The optimized Cu−SnOx hybrid nanostructures on BDDL were found to be in the size range of 50 to 100 nm with a 3 to 10 nm SnOx‐rich shell. This optimized Cu−SnOx modified BDDL electrode was tested for electrochemical CO2 reduction reaction in aqueous electrolyte and found to produce primarily CO with a Faradaic Efficiency of up to 82.5 % at −1.6 V vs Ag/AgCl.
Dynamic Nanoparticle‐Substrate Contacts Regulate Multi‐Peak Behavior of Single Silver Nanoparticle Collisions
Authors: Sun Linlin , Wang Wei , Chen Hong‐Yuan
Published: June 2018

Single nanoparticle collision (SNC) technology has attracted increasing attention to explore single nanoparticle electrochemistry. By improving the temporal resolution of electrochemical recording, several recent studies have uncovered the intermittent electron transfer processes during the SNC of single silver nanoparticles. The electrode current curve displayed multiple current peaks that were completely separated, instead of a single peak. In the present work, we employed surface plasmon resonance microscopy to monitor the collision and oxidation processes of single silver nanoparticles. Simultaneous optical and electrochemical recordings provided comprehensive capability to correlate the physical movement of nanoparticles (from optical signal) and the electron transfer activity (from electrochemical signal). While previous studies hypothesized the physical detachment of nanoparticles from the electrode due to electrostatic repulsion or Brownian motion, the optical imaging revealed that nanoparticles often remained in physical touch with the electrode even though no electron transfer was occurring. These results demonstrated that the electrical contact between nanoparticle and electrode, which could be rather stochastic due to thermal motion and micro‐convection, played critical roles in regulating the multi‐peak behavior of single silver nanoparticles.
Synthesis and Field‐Effect Transistor Application of π‐Extended Lactam‐Fused Conjugated Oligomers obtained by Tandem Direct Arylation
Authors: Takagi Koji , Yamamoto Shun‐ya , Tsukamoto Kenji , Hirano Yuto , Hara Mitsuo , Nagano Shusaku , Ie Yutaka , Takeuchi Daisuke
Published: June 2018

Five π‐extended lactam‐fused conjugated oligomers (5FO, 5FS, 4FPO, 4FPS, and R‐4FPO) were synthesized by the tandem direct arylation. The intermolecular oxidative direct arylation was applied in the second step. These conjugated oligomers had fine‐tuned FMO energies predictable by the theoretical calculation and excellent thermal stabilities. 4FPO and 4FPS bearing tetrafluoropyridine exhibited lower LUMO energy levels (−3.20 eV and −3.39 eV, respectively) compared with others. Based on the X‐ray crystallography, 4FPO was found to have a herringbone crystal packing and a considerably large electron transfer integral value (137 meV). 4FPO‐based bottom‐gate, bottom‐contact FET device demonstrated an electron mobility of 5.2×10−3 cm2 V−1 s−1 as a result of an edge‐on alignment on the SiO2 substrate.
Sugar Acetonides are a Superior Motif for Addressing the Large, Solvent‐Exposed Ribose‐33 Pocket of tRNA‐Guanine Transglycosylase
Authors: Movsisyan Levon D. , Schäfer Elisabeth , Nguyen Andreas , Ehrmann Frederik R. , Schwab Anatol , Rossolini Thomas , Zimmerli Daniel , Wagner Björn , Daff Hamina , Heine Andreas , Klebe Gerhard , Diederich François
Published: June 2018

The intestinal disease shigellosis caused by Shigella bacteria affects over 120 million people annually. There is an urgent demand for new drugs as resistance against common antibiotics emerges. Bacterial tRNA‐guanine transglycosylase (TGT) is a druggable target and controls the pathogenicity of Shigella flexneri. We report the synthesis of sugar‐functionalized lin‐benzoguanines addressing the ribose‐33 pocket of TGT from Zymomonas mobilis. Ligand binding was analyzed by isothermal titration calorimetry and X‐ray crystallography. Pocket occupancy was optimized by variation of size and protective groups of the sugars. The participation of a polycyclic water‐cluster in the recognition of the sugar moiety was revealed. Acetonide‐protected ribo‐ and psicofuranosyl derivatives are highly potent, benefiting from structural rigidity, good solubility, and metabolic stability. We conclude that sugar acetonides have a significant but not yet broadly recognized value in drug development.
Designing Metal‐Free Frustrated Lewis Pairs Catalyst for the Efficient Dehydrogenation of Ammonia Borane
Authors: Ma Gongli , Song Guoliang , Li Zhen Hua
Published: June 2018

Ammonia borane (AB) has been in the spotlight for the chemical storage of hydrogen over the past decade. However, the development of methods for efficient and controlled hydrogen release from AB under mild conditions is still underway. Herein, using density functional theory (DFT) computations, we designed a metal‐free frustrated Lewis pair (FLP) catalyst o‐(BPh2)C6H4(NiPr2) (M1) that can efficiently dehydrogenate AB to release more than two equivalents of H2 under mild conditions. Catalyst M1 can dehydrogenate not only AB to H2N=BH2 (AOB) and H2, but also oligomers of AOB with rather low free‐energy barriers. The high dehydrogenation activity of M1 is the key of new oligomerization routes to the efficient dehydrogenation of AB to borazine (BZ) or H2B−(NH=BH)n−NH2 (PIB) and finally to polyborazylene (PBZ) so that more than two equivalents of H2 can be released. A first‐principle kinetic Monte Carlo (KMC) study reveals that the activity of our catalytic system can be tuned by varying the initial concentration of M1 and AB. This work can guide the design of catalyst for the highly efficient utilization of AB as a hydrogen storage material.
Waste to Chemicals for a Circular Economy
Authors: Iaquaniello Gaetano , Centi Gabriele , Salladini Annarita , Palo Emma , Perathoner Siglinda
Published: June 2018

The implementation of a circular economy is a fundamental step to create a greater and more sustainable future for a better use of resources and energy. Wastes and in particular municipal solid waste represent an untapped source of carbon (and hydrogen) to produce a large range of chemicals from methane to alcohols (as methanol or ethanol) or urea. The waste to chemical process and related economics are assessed in this concept article to show the validity of such solution both from an economic point of view and from an environmental perspective considering the sensible reduction in greenhouse gas emissions with respect to conventional production from fossil fuels.
Enantiomeric separation of β‐blockers and tryptophan using heparin as stationary and pseudostationary phases in capillary electrophoresis
Authors: Liu Yi , Sombra Lorena L. , Stege Patricia W.
Published: June 2018

The separation methods of the enantiomers of two β‐blockers and tryptophan were studied using capillary electrochromatography with heparin covalently as well as non‐covalently, bonded onto the capillary inner wall as stationary phase and electrokinetic chromatography with heparin as pseudostationary phase. In the case of heparin, used as a stationary phase, the method was unable to resolve enantiomers in both cases β‐blockers and tryptophan. On the other hand, when heparin was used as a pseudostationary phase, the resolution of the enantiomers was obtained only with 3‐aminopropyltriethoxysilane which were immobilised onto the inner phase of the capillary. The results of this study let us infer that the electrostatic, hydrophobic, and steric interactions were involved in the separation mechanisms. The separation was achieved in less than 10 minutes under the optimized conditions: 30 mM phosphate buffer (pH 2.5) with the adding of 15 mg/mL of heparin at 15°C and 10 kV. The usefulness of heparin as a chiral selector both in electrokinetic chromatography using 3‐aminopropyltriethoxysilane attached to the capillary was demonstrated for the first time. The developed method was powerful, sensitive, and fast, and it could be considered an important alternative to conventional methods used for chiral separation.
A three‐dimensional (3D) two‐way coupled fluid‐structure interaction (FSI) study of peristaltic flow in obstructed ureters
Authors: Takaddus Ahmed Tasnub , Chandy Abhilash J.
Published: June 2018

Obstruction in the ureter flow path is one of the most common problems in urinary‐related diseases. As the ureter transports the urine using the expansion bolus created by the peristaltic pulses, an obstruction in its path can cause unwanted backflow and can also result in damage to the wall. But in order to understand this further, and specifically to quantify and parametrize the effect of the obstruction in the ureter, a detailed study investigating various level of obstructions in peristaltic ureter flow is necessary. In the current study, full 3D numerical simulations of peristalsis in an obstructed ureter are carried out using a finite element solver along with a two‐way coupling between the fluid and structural domain with the arbitrary Eulerian‐Lagrangian method. Analysis of the results shows that the larger the obstruction, the higher the wall shear stress and pressure gradient in the fluid. In addition, the amount of backflow increases with increase in the obstruction.
Precision Switching in a Discrete Supramolecular Assembly: Alkali Metal Ion‐Carboxylate Selectivities and the Cationic Hofmeister Effect
Authors: Hillyer Matthew B. , Gan Haiying , Gibb Bruce C.
Published: June 2018

A cavitand host has been shown to switch from a dimeric assembly to a tetrameric assembly in the presence of cations. Induced by pseudo‐specific cation binding attenuating the net negative charge of each host, switching was shown to be highly cation selective. Thus, the concentration of cation required to induce assembly switching ranged from 2 mM in the case of N(n‐Bu)4+ to ∼80 mM in the case of Na+. Overall cation affinity was found to be essentially the reverse of Collins’ law of matching water affinities, which predicts Na+ to have the strongest affinity for carboxylate groups. Combined with previous data, these results highlight the point that cation affinity for carboxylates are in large part dictated by context.
Intrinsic Triple Order in A‐site Columnar‐Ordered Quadruple Perovskites: Proof of Concept
Authors: Belik Alexei A. , Khalyavin Dmitry D. , Zhang Lei , Matsushita Yoshitaka , Katsuya Yoshio , Tanaka Masahiko , Johnson Roger D. , Yamaura Kazunari
Published: June 2018

There is an emerging topic in the science of perovskite materials: A‐site columnar‐ordered A2A′A′′B4O12 quadruple perovskites, which have an intrinsic triple order at the A sites. However, in many examples reported so far, A′ and A′′ cations are the same, and the intrinsic triple order is hidden. Here, we investigate structural properties of Dy2CuMnMn4O12 (1) and Ho2MnGaMn4O12 (2) by neutron and X‐ray powder diffraction and prove the triple order at the A sites. The cation distributions determined are [Ho2]A[Mn]A′[Ga0.66Mn0.34]A′′[Mn3.66Ga0.34]BO12 and [Dy2]A[Cu0.73Mn0.27]A′[Mn0.80Dy0.20]A′′[Mn1.89Cu0.11]B1[Mn2]B2O12. There are clear signatures of Jahn‐Teller distortions in 1 and 2, and the orbital pattern is combined with an original type of charge ordering in 1. Columnar‐ordered quadruple perovskites represent a new playground to study complex interactions between different electronic degrees of freedom. No long‐range magnetic order was found in 2 by neutron diffraction, and its magnetic properties in low fields are dominated by an impurity with negative magnetization or magnetization reversal. On the other hand, 1 shows three magnetic transitions at 21, 125, and 160 K.
1.0 management in a 2.0 world: Colleges between the rock and the hard place
Authors: Chu Don
Published: June 2018

If your departments are doing great, then perhaps you don't need to read this. You can just keep doing the same things to get the same results. But if you're like most leaders whose colleges have been stuck for years between “the rock and the hard place,” between growing needs and insufficient resources, then maybe you need to do things differently to get a better result. If you're still reading this, you probably believe in the power of higher education to transform lives and make our world better. Chances are you also believe in yourself, and you feel responsible to make your college and departments better. And if it takes doing things differently to get a better result, so be it.
Improvement in estimation accuracy of impedance with electrical and ultrasonic multiimaging systems
Authors: Hamatsu Fumiya , Kimoto Akira , Hamagami Tomoki
Published: June 2018

Electrical impedance imaging is an emerging medical imaging technique which can produce tomographic images of impedance properties. Many fusion systems with impedance imaging combined with other modalities are developed, but no technique currently exists of the multiimaging system that could simultaneously produce imaging of the same region. To realize the multiimaging systems, an improved fusion impedance imaging technique with electrical and ultrasonic multiimaging system is developed. Especially, this paper investigates the accuracy effects against the increasing sensor number and proposes an improved parameter adjustment method. The numerical simulation and the practical experiment are conducted on the assumption of breast cancer. The imaging result shows that the accuracy of estimating impedance can be improved by increasing the sensor number and modifying the parameter setting.
Good neighbors make good defenses: associational refuges reduce defense investment in African savanna plants
Authors: Coverdale Tyler C. , Goheen Jacob R. , Palmer Todd M. , Pringle Robert M.
Published: June 2018

Intraspecific variation in plant defense phenotype is common and has wide‐ranging ecological consequences. Yet prevailing theories of plant defense allocation, which primarily account for interspecific differences in defense phenotype, often fail to predict intraspecific patterns. Furthermore, although individual variation in defense phenotype is often attributed to ecological interactions, few general mechanisms have been proposed to explain the ubiquity of variable defense phenotype within species. Here, we show experimentally that associational refuges and induced resistance interact to create predictable intraspecific variation in defense phenotype in African savanna plants. Physically defended species from four families (Acanthaceae, Asparagaceae, Cactaceae, and Solanaceae) growing in close association with spinescent Acacia trees had 39–78% fewer spines and thorns than did isolated conspecifics. For a subset of these species, we used a series of manipulative experiments to show that this variability is maintained primarily by a reduction in induced responses among individuals that seldom experience mammalian herbivory, whether due to association with Acacia trees or to experimental herbivore exclusion. Unassociated plants incurred 4‐ to 16‐fold more browsing damage than did associated individuals and increased spine density by 16–38% within one month following simulated browsing. In contrast, experimental clipping induced no net change in spine density among plants growing beneath Acacia canopies or inside long‐term herbivore exclosures. Associated and unassociated individuals produced similar numbers of flowers and seeds, but seedling recruitment and survival were vastly greater in refuge habitats, suggesting a net fitness benefit of association. We conclude that plant‐plant associations consistently decrease defense investment in this system by reducing both the frequency of herbivory and the intensity of induced responses, and that inducible responses enable plants to capitalize on such associations in heterogeneous environments. Given the prevalence of associational and induced defenses in plant communities worldwide, our results suggest a potentially general mechanism by which biotic interactions might predictably shape intraspecific variation in plant defense phenotype.
Eligibility for cardiac resynchronization therapy in patients hospitalized with heart failure
Authors: Osmanska Joanna , Hawkins Nathaniel M. , Toma Mustafa , Ignaszewski Andrew , Virani Sean A.
Published: June 2018

Aims

Recent guidelines recommend cardiac resynchronization therapy (CRT) in mildly symptomatic heart failure (HF) but favour left bundle branch block (LBBB) morphology in patients with moderate QRS prolongation (120–150 ms). We defined how many patients hospitalized with HF fulfil these criteria.

Methods and results

A single‐centre retrospective cohort study of 363 consecutive patients hospitalized with HF (438 admissions) was performed. Electronic imaging, electrocardiograms, and records were reviewed. Overall, 153 patients (42%) had left ventricular ejection fraction (LVEF) ≤ 35%, and 34% of patients had QRS prolongation. Eighty patients (22%) were potentially eligible with LVEF ≤ 35% and QRS ≥ 120 ms or existing CRT. The majority (68 of 80) had a Class I or IIa recommendation according to international guidelines (LBBB or non‐LBBB QRS ≥ 150 ms or right ventricular pacing). Only a minority (12 of 80) had moderate QRS prolongation of non‐LBBB morphology. One‐quarter (n = 22) of patients fulfilling criteria were ineligible for reasons including dementia, co‐morbidities, or palliative care. A further eight patients required optimization of medical therapy. CRT was therefore immediately indicated in 50 patients. Of these, 29 were implanted or had existing CRT systems. Twenty‐one of the 80 patients eligible for CRT were not identified or treated (6% of the total hospitalized cohort).

Conclusions

Twenty‐two per cent of elderly real‐life patients hospitalized with HF fulfil LVEF and QRS criteria for CRT, most having a Class I or IIa indication. However, a large proportion is ineligible owing to co‐morbidities or requires medical optimization. Although uptake of CRT was reasonable, there remain opportunities for improvement.
Long-term effects and recovery of streams from acid mine drainage and evaluation of toxic metal threshold ranges for macroinvertebrate community reassembly
Authors: Herbst David B. , Medhurst R. Bruce , Black Ned J.P.
Published: June 2018

Monitoring of benthic invertebrates in streams receiving acidic metal-contaminated water over an 18-yr period revealed both degraded conditions and recovery along a network of downstream locations. Compared with reference streams, and over the course of clean-up remediation efforts below an abandoned open-pit sulfur mine in the central Sierra Nevada of California, improving water quality was accompanied by recovery of benthic communities at some sites. Years of high flow resulted in degraded biological status when acid mine drainage capture was incomplete and metal loading had increased with runoff. Seasonal patterns of recovery evident in the fall after the summer treatment season reverted in the next spring after overwinter periods when sources were not captured. As the metal load has been reduced, phased recovery of community structure, function, and similarity progressed toward that of reference assemblage taxonomic composition. From impacted communities dominated by relatively tolerant midges, reassembly involved an increase in density, return of long-lived taxa, an increased ratio of sensitive-to-tolerant forms, then overall diversity and community composition, and eventually large predators and grazers reappearing along with mayfly, stonefly, and caddisfly richness. Threshold effect levels defined using several analysis methods showed that the response range of biological indicators corresponds to US Environmental Protection Agency guidelines of predicted effects utilizing cumulative criterion units (CCUs) of metal toxicity (i.e., CCU ∼ 1). All sites have shown improved function with increased density of some or all trophic groups over time. Although recovery is progressing, year-around treatment may be necessary to fully restore biological integrity in streams nearest the mine. Environ Toxicol Chem 2018;37:2575–2592. © 2018 SETAC

Abstract

Progression of community reassembly responses with acid mine drainage recovery. These frame the predicted metal criterion sum CCUs = 1, showing mean and range of responses of threshold detection methods. First, midges as the dominant group decrease as densities of others increase, with long-lived taxa and the ratio of sensitive-to-tolerant taxa escalating; then overall diversity and community similarity rise, and finally the sensitive Ephemeroptera, Plecoptera, and Tricoptera (EPTs)—including large predators and grazers—recover.
Systematic review of prostaglandin analogues for retained placenta
Authors: Grillo‐Ardila Carlos F. , Amaya‐Guio Jairo , Ruíz‐Parra Ariel I. , Amaya‐Restrepo Juan C.
Published: June 2018

Background

Medical management of retained placenta could be a safe alternative to manual removal.

Objective

To evaluate the efficacy of prostaglandin analogues for retained placenta.

Search strategy

MEDLINE, EMBASE, CENTRAL, ICTRP, LILACS, and OpenSIGLE were searched without language restrictions from inception to January 31, 2017, by combining terms for retained placenta and prostaglandin analogues.

Selection criteria

Randomized controlled trials comparing prostaglandin analogues with any other intervention.

Data collection and analysis

Trials were independently assessed for inclusion, data extraction, and risk of bias. Data were extracted for meta‐analyses. GRADE was used to evaluate the quality of data.

Main results

Seven randomized controlled trials (851 patients) were included. Prostaglandins did not increase the placenta expulsion rate (relative risk [RR] 1.40, 95% confidence interval [CI] 0.83–2.36) or decrease maternal transfusion (RR 0.72, 95% CI 0.43–1.22). In comparison with oxytocin, prostaglandins did not modify the expulsion rate (RR 1.26, 95% CI 0.90–1.78), maternal transfusion (RR 1.05, 95% CI 0.27–4.09), or time for delivery of placenta (mean difference −1.56 minutes, 95% CI, −9.25–6.13). Three trials comparing prostaglandins with oxytocin agonists, ergometrine, and manual removal reported similar results.

Conclusions

Prostaglandin analogues do not offer an effective alternative for management of retained placenta.
Comparative molecular field analysis and hologram quantitative structure activity relationship studies of pyrimidine series as potent phosphodiesterase 10A inhibitors
Authors: Gholami Rostami Elham , Fatemi Mohammad H.
Published: June 2018

The inhibition of phosphodiesterase (PDE) 10A enzyme as an alternative approach is shown to have potential in the current treatment of schizophrenia. In the present work, the inhibition activity of 87 structurally diverse pyrimidine derivatives as PDE10A inhibitors were subjected to 2‐dimensional quantitative structure activity relationship (2D‐QSAR) and 3D‐QSAR studies using hologram QSAR and comparative molecular field analysis (CoMFA), respectively. The best CoMFA model gave a noncross‐validated correlation coefficient, () = 0.977, SEtrain = 0.247 and predictive correlation coefficient () = 0.957, and SEtest = 0.358. For the hologram QSAR (HQSAR) model, the similar parameters were , SEtrain = 0.565, , and SEtest = 0.872. The leave‐one‐out (LOO) cross‐validated r2 (q2) were 0.78 and 0.8 for the CoMFA and HQSAR models, respectively. These statistics indicate that the CoMFA model is more satisfactory than the HQSAR. Analysis of CoMFA steric and electrostatic contour maps strongly demonstrate that the presence of bulky group at the end of R1 substituent, especially heterocyclic aromatic rings, increase the inhibitory activities, and electronegative groups, such as alkoxide at the R2 position, enhance the inhibitory activities of studied chemicals. The results of this study serves as a guide for the possible modifications and designing of novel pyrimidine derivatives as new potent PDE10A inhibitors.
Phase‐Locked Lasing in 1D and 2D Patterned Metal–Organic Microcavities
Authors: Mischok Andreas , Kliem Mona , Brückner Robert , Meister Stefan , Fröb Hartmut , Gather Malte C. , Leo Karl
Published: June 2018

Organic microcavities provide unique properties that are highly advantageous for designing microlasers, but lack in efficient ways to directly integrate electrodes able to drive high currents. The introduction of thin, patterned metal films, leading to the formation of local Tamm plasmon polariton states, has been recently demonstrated as a possible route to preserving coherence in the presence of significant optical loss. Here, periodic micron‐scale gratings of silver are embedded into a high‐quality organic microcavity, creating a crystal‐like photonic potential structure. Despite strong absorption of metallic layers, these structures readily lase upon optical excitation. In that case, the above threshold emission originates not from isolate metal‐free areas but instead from phase‐locked supermodes spreading over several grating periods. Remarkably, in‐plane coherence can spread even further when decreasing the grating period, covering distances of more than 50 m and more than ten metal stripes. 1D and 2D gratings with varying periods are investigated using tomographic scanning of the k‐space emission fine structure, which exhibits a strong dependence on the grating geometry. These results support the fabrication of highly customizable organic microlasers with tailored in‐plane coherence, and demonstrate the coexistence of extended coherence and optical loss.
Hamsters Are a Better Model System than Rats for Evaluating the Hypocholesterolemic Efficacy of Potential Probiotic Strains
Authors: Guo Chun‐Feng , Yuan Ya‐Hong , Yue Tian‐Li , Li Jing‐Yan
Published: June 2018

Scope

Rats and hamsters are the most commonly used animal models for evaluating the hypocholesterolemic activity of potential probiotic strains, whereas little or no information has been reported on whether the animal models would affect the experimental conclusions regarding the hypocholesterolemic efficacy of the strains.

Methods and results

Both high‐cholesterol‐fed rats and hamsters were intragastrically administered viable cells of bile salt hydrolase‐active Lactobacillus acidophilus K16 once daily (1 × 1010 CFU per kg body weight) for 28 d. It was found that the strain did not significantly (p > 0.05) affect the serum and hepatic cholesterol levels in rats, whereas it significantly decreased (p < 0.01 or p < 0.001) the serum total and non‐HDL‐cholesterol as well as hepatic‐free, esterified, and total cholesterol levels in hamsters by 29.6%, 38.8%, 15.8%, 36.2%, and 34.0%, respectively.

Conclusion

These data suggest that the hypocholesterolemic efficacy of L. acidophilus K16 is substantially different between high‐cholesterol‐fed hamsters and rats and that hamsters are a better model system than rats for evaluating the hypocholesterolemic efficacy of potential probiotic strains due to their similarity to humans in biliary bile acid composition, including types of bile acids and their conjugation form.
Count statistics of nonparalyzable photon‐counting detectors with nonzero pulse length
Authors: Grönberg Fredrik , Danielsson Mats , Sjölin Martin
Published: June 2018

Purpose

Photon‐counting detectors are expected to be the next big step in the development of medical computed tomography (CT). Accurate modeling of the behavior of photon‐counting detectors in both low and high count rate regimes is important for accurate image reconstruction and detector performance evaluations. The commonly used ideal nonparalyzable (delta pulse) model is built on crude assumptions that make it unsuitable for predicting the behavior of photon‐counting detectors at high count rates. The aim of this work is to present an analytical count statistics model that better describes the behavior of photon‐counting detectors with nonzero pulse length.

Methods

An analytical statistical count distribution model for nonparalyzable detectors with nonzero pulse length is derived using tools from statistical analysis. To validate the model, a nonparalyzable photon‐counting detector is simulated using Monte Carlo methods and compared against. Image performance metrics are computed using the Fisher information metric and a comparison between the proposed model, approximations of the proposed model, and those made by the ideal nonparalyzable model is presented and analyzed.

Results

It is shown that the presented model agrees well with the results from the Monte Carlo simulation and is stable for varying x‐ray beam qualities. It is also shown that a simple Gaussian approximation of the distribution can be used to accurately model the behavior and performance of nonparalyzable detectors with nonzero pulse length. Furthermore, the comparison of performance metrics show that the proposed model predicts a very different behavior than the ideal nonparalyzable detector model, suggesting that the proposed model can fill an important gap in the understanding of pileup effects.

Conclusions

An analytical model for the count statistics of a nonparalyzable photon‐counting detector with nonzero pulse length is presented. The model agrees well with results obtained from Monte Carlo simulations and can be used to improve, speed up and simplify modeling of photon‐counting detectors.
Assessments of tumor metabolism with CEST MRI
Authors: Goldenberg Joshua M. , Pagel Mark D.
Published: June 2018

Chemical exchange saturation transfer (CEST) is a relatively new contrast mechanism for MRI. CEST MRI exploits a specific MR frequency (chemical shift) of a molecule while generating an image with good spatial resolution using standard MRI techniques, combining the specificity of MRS with the spatial resolution of MRI. Many CEST MRI acquisition methods have been developed to improve analyses of tumor metabolism. GluCEST, CrCEST, and LATEST can map glutamate, creatine, and lactate, which are important metabolites involved in tumor metabolism. GlucoCEST MRI tracks the pharmacokinetics of glucose transport and cell internalization within tumors. CatalyCEST MRI detects enzyme catalysis that changes a substrate CEST agent. AcidoCEST MRI measures extracellular pH of the tumor microenvironment by exploiting a ratio of two pH‐dependent CEST signals. This review describes each technique, the technical issues involved with CEST MRI and each specific technique, and the merits and challenges associated with applying each CEST MRI technique to study tumor metabolism.
Nutrition Management of Necrotizing Enterocolitis
Authors: Christian Vikram J. , Polzin Elizabeth , Welak Scott
Published: June 2018

Necrotizing enterocolitis (NEC) is one of the most significant causes of morbidity and mortality among premature infants. The exact cause is considered multifactorial and related to gastrointestinal immaturity, inflammation and enteral feeding. The role of nutrition is vitally important in NEC. The main modifiable risk factor is the introduction and advancement of enteral feedings. After an infant has recovered from NEC, enteral feeds should be cautiously resumed to prevent injury from prolonged use of parenteral nutrition. The logistics of how, when, and what to feed are somewhat unclear and often depend on the severity of the disease. For patients with an enterostomy, refeeding the distal intestine with the small‐intestinal ostomy output may improve bowel growth and prevent long‐term complications.
Colonic Mucosal Proteome Signature Reveals Reduced Energy Metabolism and Protein Synthesis but Activated Autophagy during Anorexia‐Induced Malnutrition in Mice
Authors: Nobis Séverine , Achamrah Najate , Goichon Alexis , L'Huillier Clément , Morin Aline , Guérin Charlène , Chan Philippe , do Rego Jean Luc , do Rego Jean Claude , Vaudry David , Déchelotte Pierre , Belmonte Liliana , Coëffier Moïse
Published: June 2018

Anorexia nervosa is an eating disorder often associated with intestinal disorders. To explore the underlying mechanisms of these disorders, the colonic proteome was evaluated during activity‐based anorexia. Female C57Bl/6 mice were randomized into three groups: Control, Limited Food Access (LFA) and Activity‐Based Anorexia (ABA). LFA and ABA mice had a progressive limited access to food but only ABA mice had access to an activity wheel. On colonic mucosal protein extracts, a 2D PAGE‐based comparative proteomic analysis was then performed and differentially expressed proteins were identified by LC‐ESI‐MS/MS. Twenty‐seven nonredundant proteins that were differentially expressed between Control, LFA, and ABA groups were identified. ABA mice exhibited alteration of several mitochondrial proteins involved in energy metabolism such as dihydrolipoyl dehydrogenase and 3‐mercaptopyruvate sulfurtransferase. In addition, a downregulation of mammalian target of rapamycin (mTOR) pathway was observed leading, on the one hand, to the inhibition of protein synthesis, evaluated by puromycin incorporation and mediated by the increased phosphorylation of eukaryotic elongation factor 2, and on the other hand, to the activation of autophagy, assessed by the increase of the marker of autophagy, form LC3‐phosphatidylethanolamine conjugate/Cytosolic form of Microtubule‐associated protein 1A/1B light chain 3 (LC3II/LC3I) ratio. Colonic mucosal proteome is altered during ABA suggesting a downregulation of energy metabolism. A decrease of protein synthesis and an activation of autophagy were also observed mediated by mTOR pathway.
A theoretical study on excited state proton transfer in 2‐(2′‐dihydroxyphenyl) benzoxazole
Authors: Li Jia , Zhang Meixia , Du Can , Song Peng , Li Xiaodong
Published: June 2018

This research investigates the dynamic excited state process for a novel system 2‐(2′‐dihydroxyphenyl) benzoxazole (DHBO) for excited state proton transfer (ESPT) process based on density functional theory (DFT) and time‐dependent DFT (TDDFT) methods. Because 2 intramolecular hydrogen bonds (O1―H2···N3 and O4―H5···O6) in DHBO molecules may trigger proton transfer process in the S1 state, we focus on these 2 hydrogen bonds. Our results show that only the O1―H2···N3 bond has obvious changes in both bond length and bond angle upon photoexcitation. Charge redistribution also confirms that hydrogen bond wire (O1―H2···N3) is the best way to achieve the ESPT process in the S1 state. Considering the ESPT mechanism, our theoretical potential energy curves of DHBO indicate that only the excited state single‐proton transfer process occurs via O1―H2···N3 rather than O4―H5···O6. We believe that our work not only clarifies the excited state dynamical behavior of DHBO but also promotes the investigations about ESPT reactions in intramolecular or intermolecular hydrogen bonded chemical systems.
Silicon Solar Cells with Embedded Silicon‐on‐Insulation Layer via Nitrogen Ion Beam Implantation
Authors: Sahu Rajkumar , Palei Srikanta , Mun Jonghun , Kim Keunjoo
Published: June 2018

In this research, silicon solar cells with embedded silicon‐on‐insulation layer obtained via nitrogen ion beam implantation are investigated. The embedded layer acts as a minority carrier‐blocking layer for the silicon solar cells, which results in the suppression of carrier recombination from the surface due to the formation of the silicon‐on‐insulation layer. This is achieved by integrating nitrogen ion implantation as a carrier reduction layer, which has a band offset asymmetry with silicon. The implantation is involved with the formation of surface defects by forming amorphous layers on Si surfaces. The electroluminescence images show that defects related to high energy nitrogen ion implantation are involved in the emission mechanism compared to low energy implanted nitrogen ion. From current–voltage analysis, the conversion efficiencies of nitrogen ion implanted cells are found lower than the reference cell, but the cell implanted with low energy nitrogen ion enhances the short circuit current density.
Imaging Ellipsometry Determination of the Refractive Index Contrast and Dispersion of Channel Waveguides Inscribed by fs‐Laser Induced Ion‐Migration
Authors: Moreno‐Zarate Pedro , Gonzalez Antonio , Funke Sebastian , Días Antonio , Sotillo Belen , del Hoyo Jesus , Garcia‐Pardo Marina , Serna Rosalia , Fernandez Paloma , Solis Javier
Published: June 2018

The measurement of the refractive index of optical waveguides is a difficult task that involves different methods, among which those based on the refracted near field determination (RNF) are likely the ones providing the best resolution. Still, most such methods lack spectral resolution, which impedes accessing the index dispersion of the waveguide, an essential parameter for many applications. In this work, the refractive index of channel waveguides produced by fs‐laser induced ion‐migration in a P2O5‐La2O3‐K2O‐based glass is measured by imaging ellipsometry. Along with EDX compositional maps and guiding performance, the dispersion and refractive index maps of several waveguides are measured. The results confirm that, in this glass, waveguides are formed due to an enrichment in La in the topmost part of the laser‐excited region which is accompanied by the cross migration of K toward the region underneath. Interestingly, the index contrast of the waveguides shows a wavelength‐independent behavior for wavelengths above ≈600 nm. This indicates that in the compositional range analyzed, La3+ ions linearly contribute to the glass polarizability due to the relatively large mass of La3+ ions and the relatively small size of the isolated La‐polyhedra accommodated in the phosphate glass network.
Field‐Controlled Quantum Dot to Ring Transformation in Wave‐Function Tunable Cone‐Shell Quantum Structures
Authors: Heyn Christian , Küster Achim , Zocher Michael , Hansen Wolfgang
Published: June 2018

A new type of quantum structure is discussed where the probability distributions of the charge carriers are concentrated on the shell of a cone. These GaAs cone‐shell quantum structures (CSQSs) are filled into nanoholes in AlGaAs that are fabricated in a self‐assembled fashion using local droplet etching during molecular beam epitaxy. The structural properties of the CSQSs are studied with atomic force microscopy (AFM) and the optical emission with single‐dot photoluminescence (PL). Numerical simulations of the influence of a vertical electric field predict a strong field‐dependent displacement of either the electron or the hole away from the tip of the cone shell. This displacement has several consequences. First, the Coulomb interaction is strongly reduced. Accordingly, simulations as well as PL measurements indicate a non‐parabolic Stark‐shift for CSQSs with a regime of approximately constant emission energy. Second, the calculated exciton‐recombination lifetimes establish a variability from nanoseconds up to milliseconds. Third, regarding the shape of the electron or hole probability distributions, we predict a gate‐voltage controlled transformation from a dot into a ring shape. The respective other charge carrier remains as a dot.
Atmospheric blocking and upper‐level Rossby‐wave forecast skill dependence on model configuration
Authors: Martínez‐Alvarado Oscar , Maddison Jacob W. , Gray Suzanne L. , Williams Keith D.
Published: June 2018

Weather models differ in their ability to forecast, at medium range, atmospheric blocking and the associated structure of upper‐level Rossby waves. Here, we evaluate the effect of a model's dynamical core on such forecasts. Operational forecasts from the ensemble prediction systems (EPSs) of the European Centre for Medium‐Range Weather Forecasts (ECMWF), the Met Office (MO) and the Korean Meteorological Administration (KMA) are used. Northern Hemisphere model output is analysed from the winters before and after a major upgrade to the dynamical core of the MO‐EPS (called MOGREPS). The KMA‐EPS acts as a control as it uses the same model as MOGREPS, but uses the older dynamical core throughout. The confounding factor of resolution differences between MOGREPS and the KMA‐EPS is assessed using a MO forecast model hindcast experiment with the more recent dynamical core, but with the operational resolution of the KMA‐EPS. The introduction of the new dynamical core in MOGREPS has led to increased forecast blocking frequency, at lead times of 5 and 7 days, counteracting the typically observed reduction in blocking frequency with lead time. Hit rates of blocking activity, onset and decay are also increased in the main blocking regions (without a corresponding increase in the false positive rate). The previously found reduction of the upper‐level ridge area and tropopause sharpness (measured by an isentropic potential vorticity gradient) with lead time is also reduced with the new dynamical core. This dynamical core improvement (associated with a reduction in implicit damping) is thus demonstrated to be at least as effective as operational resolution improvements in improving the forecasts of upper‐level Rossby waves and associated blocking.
Delay compensation for linear systems with both state and distinct input delays
Authors: Liu Qingsong , Zhou Bin
Published: June 2018

This paper is concerned with the stabilization of linear systems with both state and distinct input delays. Nested predictor feedback controllers are designed to predict the future states such that the distinct input delays that can be arbitrarily large yet bounded are compensated completely. It is shown that the compensated closed‐loop system possesses the same characteristic equation as the closed‐loop system without distinct input delays. Both continuous‐time and discrete‐time time‐delay systems are studied in this paper. Moreover, the safe implementation problem for the continuous‐time nested predictor feedback controller is solved via adding input filters. Three numerical examples show the effectiveness of the proposed approaches.
Know how to comply with training requirements for stalking prevention, awareness
Authors: McCarthy Claudine
Published: June 2018

The Violence Against Women Act amendments to the Clery Act require colleges and universities to provide annual prevention and awareness training about stalking and other forms of sexual violence. To promote compliance with these training requirements, Kaitlin Zies, assistant director of student conduct, and Nicholas Campau, associate dean of student life and director of student conduct, both at Ferris State University, addressed the topic at the annual conference for the Association for Student Conduct Administration.
Was university liable for coach's alleged sexual harassment?
Authors: Gelpi Aileen
Published: June 2018

In 2015, Florida International University Women's Basketball Head Coach Marlin Chinn allegedly began asking team member Destini Feagin for details about her love life and giving her unwanted advice on ways to please men.
Student‐focus, hard work pave way to presidency
Authors: McCarthy Claudine
Published: June 2018

A first‐generation, low‐income scholar from an impoverished Detroit neighborhood, Dwaun J. Warmack, Ed.D., defied all odds when, in 2014, at the age of 37, he became one of the youngest presidents of a four‐year institution.
Estimation of exposure‐attributable fractions from time series: A simulation study
Authors: Cheysson Felix , Vibet Marie‐Anne , Guillemot Didier , Watier Laurence
Published: June 2018

Burden analysis in public health often involves the estimation of exposure‐attributable fractions from observed time series. When the entire population is exposed, the association between the exposure and outcome must be carefully modelled before the attributable fractions can be estimated. This article derives asymptotic convergences for the estimation of attributable fractions for commonly used time series models (ARMAX, Poisson, negative binomial, and Serfling), using for the most part the delta method. For the Poisson regression, the estimation of the attributable fraction is achieved by a Monte Carlo algorithm, taking into account both an estimation and a prediction error. A simulation study compares these estimations in the case of an epidemic exposure and highlights the importance of thorough analysis of the data: When the outcome is generated under an additive model, the additive models are satisfactory, and the multiplicative models are poor, and vice versa. However, the Serfling model performs poorly in all cases. Of note, a misspecification in the form or delay of the association between the exposure and the outcome leads to mediocre estimation of the attributable fraction. An application to the fraction of French outpatient antibiotic use attributable to influenza between 2003 and 2010 illustrates the asymptotic convergences. This study suggests that the Serfling model should be avoided when estimating attributable fractions while the model of choice should be selected after careful investigation of the association between the exposure and outcome.
A class of semiparametric tests of treatment effect robust to confounder measurement error
Authors: Miles Caleb H. , Schwartz Joel , Tchetgen Tchetgen Eric J.
Published: June 2018

When assessing the presence of an exposure causal effect on a given outcome, measurement error of a confounder can inflate the type I error rate of a treatment effect in even the simplest of settings. In this paper, we develop a large class of semiparametric test statistics of an exposure causal effect, which are completely robust to additive unbiased measurement error of a subset of confounders. A unique and appealing feature of our proposed methodology is that it requires no external information such as validation data or replicates of error‐prone confounders. We present a doubly robust form of this test that requires the exposure mean model to be linear in the mismeasured confounders, and only one of two models involving error‐free confounders to be correctly specified for the resulting test statistic to have correct type I error rate. We demonstrate validity within our class of test statistics through simulation studies. We apply the methods to a multi–US‐city time‐series data set to test for an effect of temperature on mortality while adjusting for atmospheric particulate matter with diameter of 2.5 micrometres or less, which is known to be measured with error.
Synthesis, Characterization and Biocompatibility of Mesolamellar Calcium Phosphate Hybrids Prepared by Anionic Surfactant Templating
Authors: Salinas Antonio J. , Blanco‐Bécares José M. , Mersinlioglu Okan , Casarrubios Laura , Fernández‐Villa Daniel , Feito María J. , Portolés Teresa , González Blanca , Vallet‐Regí María
Published: June 2018

Calcium phosphate (CaP) based hybrid materials have been synthesized through a precipitation method in aqueous medium in the presence of the anionic surfactant sodium dodecylbenzene sulfonate (SDBS) as structure directing agent. Parameters of synthesis, such as Ca/P molar ratio, surfactant concentration and initial pH, have been investigated trying to get mesostructured CaP phases. A lamellar‐like hybrid mesophase consisting in several wavy layers of apatite or apatite‐brushite nanoplates was successfully obtained. Materials have been characterized by several physico‐chemical techniques. A potential application of these lamellar calcium phosphate based hybrids can be as matrixes in drug delivery systems with the possibility of loading hydrophobic drugs in the organic interlayers. To evaluate their potential as biomaterials, the biocompatibility of two hybrids has been studiedin vitrowith human Saos‐2 osteoblasts. Cell assays showed that, upon the appropriate synthesis and stabilization conditions, a biocompatible CaP and SDBS mesolamellar hybrid can be prepared.