bluuebunny/crossref_metadata_2025 huggingface dataset:
Prehospital triage of acute aortic syndrome using a machine learning algorithm
Authors: Duceau B , Alsac J-M , Bellenfant F , Mailloux A , Champigneulle B , Favé G , Neuschwander A , El Batti S , Cholley B , Achouh P , Pirracchio R
Published: February 2020

Background

Acute aortic syndrome (AAS) comprises a complex and potentially fatal group of conditions requiring emergency specialist management. The aim of this study was to build a prediction algorithm to assist prehospital triage of AAS.

Methods

Details of consecutive patients enrolled in a regional specialist aortic network were collected prospectively. Two prediction algorithms for AAS based on logistic regression and an ensemble machine learning method called SuperLearner (SL) were developed. Undertriage was defined as the proportion of patients with AAS not transported to the specialist aortic centre, and overtriage as the proportion of patients with alternative diagnoses but transported to the specialist aortic centre.

Results

Data for 976 hospital admissions between February 2010 and June 2017 were included; 609 (62·4 per cent) had AAS. Overtriage and undertriage rates were 52·3 and 16·1 per cent respectively. The population was divided into a training cohort (743 patients) and a validation cohort (233). The area under the receiver operating characteristic (ROC) curve values for the logistic regression score and the SL were 0·68 (95 per cent c.i. 0·64 to 0·72) and 0·87 (0·84 to 0·89) respectively (P < 0·001) in the training cohort, and 0·67 (0·60 to 0·74) and 0·73 (0·66 to 0·79) in the validation cohort (P = 0·038). The logistic regression score was associated with undertriage and overtriage rates of 33·7 (bootstrapped 95 per cent c.i. 29·3 to 38·3) and 7·2 (4·8 to 9·8) per cent respectively, whereas the SL yielded undertriage and overtriage rates of 1·0 (0·3 to 2·0) and 30·2 (25·8 to 34·8) per cent respectively.

Conclusion

A machine learning prediction model performed well in discriminating AAS and could be clinically useful in prehospital triage of patients with suspected AAS.
Undifferentiated pleomorphic sarcoma of the thyroid: A case report and ƚiterature review
Authors: Nguyen Van Bang , Nguyen Van Vy Hau , Tran Binh Thang , Le Chi Van , Dang Cong Thuan , Baek Jung Hwan
Published: February 2020

This report describes a patient who presented with a large thyroid nodule and compressive symptoms. Immunohistochemical staining showed diffuse marked reactivity for vimentin and focal reactivity for CD68 and Ki‐67 that is compatible with primary undifferentiated pleomorphic sarcoma of the thyroid. This report emphasizes and discusses extremely rare thyroid cancer type.
Utilization of Formic Acid as C1 Building Block for the Ruthenium‐Catalyzed Synthesis of Formaldehyde Surrogates
Authors: Beydoun Kassem , Thenert Katharina , Wiesenthal Jan , Hoppe Corinna , Klankermayer Jürgen
Published: February 2020

Dialkoxymethanes are becoming increasingly important as fuel additives, formaldehyde surrogates, and chemical intermediates, but the effective synthesis remains challenging. Herein, the catalytic synthesis of dialkoxymethane products using a molecular catalyst is reported. The catalytic system, comprising the [Ru(triphos)(tmm)] in combination with the Lewis acid Al(OTf)3, enables the direct synthesis of dialkoxymethane products with formic acid as C1 building block in high to excellent turnover numbers.
FeNi Alloy Nanoparticles Encapsulated in Carbon Shells Supported on N‐Doped Graphene‐Like Carbon as Efficient and Stable Bifunctional Oxygen Electrocatalysts
Authors: Li Guang‐Lan , Yang Bei‐Bei , Xu Xiao‐Cun , Cao Shuo , Shi Yantao , Yan Yang , Song Xuedan , Hao Ce
Published: February 2020

The development of cost‐effective and durable oxygen electrocatalysts remains highly critical but challenging for energy conversion and storage devices. Herein, a novel FeNi alloy nanoparticle core encapsulated in carbon shells supported on a N‐enriched graphene‐like carbon matrix (denoted as FeNi@C/NG) was constructed by facile pyrolyzing the mixture of metal salts, glucose, and dicyandiamide. The in situ pyrolysis of dicyandiamide in the presence of glucose plays a significant effect on the fabrication of the porous FeNi@C/NG with a high content of doped N and large specific surface area. The optimized FeNi@C/NG catalyst displays not only a superior catalytic performance for the oxygen reduction reaction (ORR, with an onset potential of 1.0 V and half‐wave potential of 0.84 V) and oxygen evolution reaction (OER, the potential at 10 mA cm−2 is 1.66 V) simultaneously in alkaline, but also outstanding long‐term cycling durability. The excellent bifunctional ORR/OER electrocatalytic performance is ascribed to the synergism of the carbon shell and FeNi alloy core together with the high‐content of nitrogen doped on the large specific surface area graphene‐like carbon.
Structural Tunability and Diversity of Two‐Dimensional Lead Halide Benzenethiolate
Authors: Coffey Aidan H. , Yoo Pilsun , Kim Dong Hee , Akriti  , Zeller Matthias , Avetian Sona , Huang Libai , Liao Peilin , Dou Letian
Published: February 2020

Two‐dimensional (2D) organic‐inorganic hybrid materials are currently of great interest for applications in electronics and optoelectronics. Here, the synthesis and optical properties of a new type of halide‐organothiolate‐mixed 2D hybrid material, Pb2X(S‐C6H5)3, are reported, in which X is a halide (I, Br, or Cl). Different from conventional lead‐based 2D layered materials, these compounds feature unusual five‐coordinated lead centers with a stereochemically active electron lone pair on the lead atoms and four‐coordinated iodine atoms. The Pb2X(S‐C6H5)3 materials feature an indirect bandgap, strongly emissive long‐lived self‐trap states, and an extremely large Stokes shift. Interestingly, the optical bandgap of the materials can be tuned through variation of the halides; however, the photoluminescence is less sensitive to the composition and is more likely dominated by lead‐sulfur lattice interactions or the lead lone‐pair electrons. Our results support that a halide–organothiolate mixed anion hybrid structure offers a unique platform for discovering new exciting 2D electronic materials.
Cobalt(II)‐Catalyzed [4+2] Annulation of Picolinamides with Alkynes via C−H Bond Activation
Authors: Yao Yongqi , Lin Qifu , Yang Wen , Yang Weitao , Gu Fenglong , Guo Wei , Yang Dingqiao
Published: February 2020

A cobalt(II)‐catalyzed [4+2] annulation of picolinamides with alkynes via C−H bond activation has been developed. The operationally simple annulation reaction allows for the synthesis of acyl‐substituted 1H‐benzoquinoline bearing multiple aromatic rings (up to 96 % yield) without co‐oxidant or other oxidation factors under mild conditions. Several control experiments were carried out. This practical [4+2] annulation provides an efficient route to access highly functionalized compounds.
Theoretical Analysis of the Mackay Icosahedral Cluster Pd55(PiPr3)12(μ3‐CO)20: An Open‐Shell 20‐Electron Superatom
Authors: Wei Jianyu , Marchal Rémi , Astruc Didier , Saillard Jean‐Yves , Halet Jean‐François , Kahlal Samia
Published: February 2020

The electronic structure of the spherical Mackay icosahedral nanosized cluster Pd55(PiPr3)12(μ3‐CO)20 is analyzed by using DFT calculations. Results reveal that it can be considered as a regular superatom with a “magic” electron count of 20, characterized by a 1S2 1P6 1D10 2S2 jellium configuration. Its open shell nature is associated with partial occupation of non‐jellium, 4d‐type, levels located on the interior of the Pd55 kernel. This shows that the superatom model can be used to rationalize the bonding and stability of spherical ligated group 10 clusters, despite their apparent 0‐electron count.
Explosionsschutz
Authors: Schöllhorn Anna , Wörsdorfer Klaus
Published: February 2020

Durch eine Vielzahl an Stoffen kann in Form von Gasen, Dämpfen, Nebel oder Stäuben, eine explosionsfähige Atmosphäre gebildet werden. Für den Explosionsschutz von besonderer Relevanz ist dabei die Bildung einer gefährlichen explosionsfähigen Atmosphäre (= g.e.A.), da diese in einer solchen gefahrdrohenden Menge gebildet wird, so dass ein einziger Zündfunke zu einer Explosion führen kann. Dafür sind Schutzmaßnahmen zum Schutz von Sicherheit und Gesundheit der Beschäftigten oder Dritter erforderlich. In der Europäischen Union ist jeder Hersteller von Maschinen beim Einbringen von Produkten in den europäischen Markt verpflichtet, die Risiken durch eine gefährliche explosionsfähige Atmosphäre zu berücksichtigen. Dieser erste Beitrag einer dreiteiligen Artikelserie geht auf die gesetzlichen Vorgaben ein, die durch die Hersteller von Maschinen berücksichtigt werden müssen.
Schließschlagarm
Authors: Mueterthies Thomas
Published: February 2020

Um kompakte Ventile größerer Nennweite auf kleinstem Bauraum anzusteuern, hat der Fluidikspezialist Bürkert Fluis Control Systems das TwinPower‐Spulensystem entwickelt.
Materialdaten sammeln
Authors: Oberdorfer Phillip
Published: February 2020

Bei der Modellierung mit Comsol Multiphysics arbeitet man in der Regel mit Materialmodellen, die alle für eine Simulation benötigten Materialdaten enthalten. Mit dem Release der neuen Version 5.5 ist es nun möglich, in Comsol Materialmodelle aus den thermodynamischen Eigenschaften von Gemischen zu erstellen. Eigenschaften wie Dichte, Wärmekapazität, dynamische Viskosität, Diffusität und Wärmeleitfähigkeit von Gemischen können so in das Material einbezogen werden.
Vollständig trockenlaufend und hermetisch gasdicht
Authors: Koester William
Published: February 2020

Der neue Haug.Sirius NanoLoc von Sauer Compressors ist eine vollständig trockenlaufende und gasdichte Lösung für Anwendungen, die Prozesssicherheit und ‐reinheit verlangen.
Sodium‐ion capacitors: Materials, Mechanism, and Challenges
Authors: Zhang Yadi , Jiang Jiangmin , An Yufeng , Wu Langyuan , Dou Hui , Zhang Jiaoxia , Zhang Yu , Wu Shide , Dong Mengyao , Zhang Xiaogang , Guo Zhanhu
Published: February 2020

Sodium‐ion capacitors (SICs), designed to attain high energy density, rapid energy delivery, and long lifespan, have attracted much attention because of their comparable performance to lithium‐ion capacitors (LICs), alongside abundant sodium resources. Conventional SIC design is based on battery‐like anodes and capacitive cathodes, in which the battery‐like anode materials involve various reactions, such as insertion, alloying, and conversion reactions, and the capacitive cathode materials usually depend on activated carbon (AC). However, researchers have attempted to construct SICs based on battery‐like cathodes and capacitive anodes or a combination of both in recent years. In this Minireview, charge storage mechanisms and material design strategies for SICs are summarized, with a focus on the battery‐like anode materials from both inorganic and organic sources. Additionally, the challenges in the fabrication of SICs and future research directions are discussed.
Evidence of ecological niche shift in Rhododendron ponticum (L.) in Britain: Hybridization as a possible cause of rapid niche expansion
Authors: Manzoor Syed Amir , Griffiths Geoffrey , Obiakara Maxwell C. , Esparza‐Estrada Citlalli Edith , Lukac Martin
Published: February 2020

Biological invasions threaten global biodiversity and natural resources. Anticipating future invasions is central to strategies for combating the spread of invasive species. Ecological niche models are thus increasingly used to predict potential distribution of invasive species. In this study, we compare ecological niches of Rhododendron ponticum in its native (Iberian Peninsula) and invasive (Britain) ranges. Here, we test the conservation of ecological niche between invasive and native populations of R. ponticum using principal component analysis, niche dynamics analysis, and MaxEnt‐based reciprocal niche modeling. We show that niche overlap between native and invasive populations is very low, leading us to the conclusion that the two niches are not equivalent and are dissimilar. We conclude that R. ponticum occupies novel environmental conditions in Britain. However, the evidence of niche shift presented in this study should be treated with caution because of nonanalogue climatic conditions between native and invasive ranges and a small population size in the native range. We then frame our results in the context of contradicting genetic evidence on possible hybridization of this invasive species in Britain. We argue that the existing contradictory studies on whether hybridization caused niche shift in R. ponticum are not sufficient to prove or disprove this hypothesis. However, we present a series of theoretical arguments which indicate that hybridization is a likely cause of the observed niche expansion of R. ponticum in Britain.
Recent Catalytic Applications of (Cyclopentadienone)iron Complexes
Authors: Pignataro Luca , Gennari Cesare
Published: February 2020

(Cyclopentadienone)iron complexes (CICs) are attractive pre‐catalysts due to their easy preparation and robustness, which are uncommon features in homogeneous iron catalysis. They represent a striking example of how deeply a non‐innocent ligand may affect the catalytic properties of the metal. Swinging between the cyclopentadienone and the hydroxycyclopentadienyl form, the ligand induces iron to engage in H2 heterolytic cleavage and transfer. The latter represents the basis for numerous applications of CICs in redox chemistry (multiple bond reduction, alcohol oxidation) and “hydrogen borrowing” processes (e.g., alcohol amination) that have been reported over the last few years. Moreover, very recently catalytic applications of CICs in different types of reactivity (where again the non‐innocent ligand plays a key role), have appeared in the literature. This minireview summarizes the advancements that have been made in the field of CICs and their catalytic applications in the period 2014–2019.
Posttraumatic stress disorder predicts non‐completion of day hospital treatment for bulimia nervosa and other specified feeding/eating disorder
Authors: Trottier Kathryn
Published: February 2020

Objective

The aim of this study was to determine whether posttraumatic stress disorder (PTSD) predicts non‐completion of CBT‐based day hospital treatment for bulimia nervosa (BN) and other specified feeding and eating disorder (OSFED).

Method

Participants were 151 day hospital patients with BN or OSFED. Participants were assessed at pretreatment via interview and self‐report measures. Cox regression was used to model the rate and timing of treatment termination; pretreatment binge and vomit frequencies, eating disorder‐related clinical impairment, depression, and ED psychopathology were entered as covariates.

Results

Participants who screened positive for PTSD (n = 64) had more severe ED psychopathology, ED‐related impairment, negative schemas, and depression relative to those who did not screen positive. Cox regression indicated that PTSD significantly predicted premature termination and was associated with a 2.32 times greater risk. Individuals with BN or OSFED and co‐occurring PTSD were particularly likely to terminate in the early phase of treatment compared with later in treatment.

Conclusion

PTSD appears to affect some individuals' ability to complete intensive ED treatment. Future research should examine whether PTSD predicts premature termination from less intensive ED treatments, as well as in other intensive treatment settings, and whether PTSD predicts poorer outcomes from ED treatment.
Food hazards on the European Union market: The data analysis of the Rapid Alert System for Food and Feed
Authors: Pigłowski Marcin
Published: February 2020

The aim of the study was to examine similarities in notifications on main hazards within food reported in the Rapid Alert System for Food and Feed (RASFF) in 1979–2017. The main problems were mycotoxins in nuts, pathogenic microorganisms in poultry meat and fish, pesticide residues in fruits and vegetables, and heavy metals in fish. The increase in the number of notifications has been observed since 2002/2003. Products were notified mainly by Italy, Germany, and United Kingdom and originated from Asian and European Union countries. The notification basis was border control and official control, and the notification type was border rejections, information, and alerts. Notified products were not distributed and not placed on the market, distribution status could be also not specified, or distribution was possible, also to other countries. The risk decision on hazard was usually not made. Products were redispatched, withdrawn from the market, and destroyed, or import was not authorized. Remarks, which can be used to improve the RASFF database, were also presented. It was further pointed out that European law should significantly reduce the use of pesticides, drugs, and food additives, and European agriculture should be reoriented from an intensive farming to a more sustainable and ecological one.
Untethered firing fields and intermittent silences: Why grid‐cell discharge is so variable
Authors: Nagele Johannes , Herz Andreas V.M. , Stemmler Martin B.
Published: February 2020

Grid cells in medial entorhinal cortex are notoriously variable in their responses, despite the striking hexagonal arrangement of their spatial firing fields. Indeed, when the animal moves through a firing field, grid cells often fire much more vigorously than predicted or do not fire at all. The source of this trial‐to‐trial variability is not completely understood. By analyzing grid‐cell spike trains from mice running in open arenas and on linear tracks, we characterize the phenomenon of “missed” firing fields using the statistical theory of zero inflation. We find that one major cause of grid‐cell variability lies in the spatial representation itself: firing fields are not as strongly anchored to spatial location as the averaged grid suggests. In addition, grid fields from different cells drift together from trial to trial, regardless of whether the environment is real or virtual, or whether the animal moves in light or darkness. Spatial realignment across trials sharpens the grid representation, yielding firing fields that are more pronounced and significantly narrower. These findings indicate that ensembles of grid cells encode relative position more reliably than absolute position.
The effect of CEO incentives on deviations from institutional norms in foreign market expansion decisions: Behavioral agency and cross‐border acquisitions
Authors: Benischke Mirko H. , Martin Geoffrey P. , Gomez‐Mejia Luis R. , Ljubownikow Grigorij
Published: February 2020

CEO incentives have been the subject of great interest for human resource scholars. We explore the institutional context within which the CEO makes sense of their incentives. Our theory suggests that CEO equity incentives interact with institutional norms to influence foreign market entry choices. Specifically, we argue that CEOs will weigh the risk bearing created by equity incentives, along with the consequences of legitimacy loss, when deciding whether to deviate from institutional norms when internationalizing. In doing so, we advance human resource literature by demonstrating that CEO responses to incentives are influenced by institutional norms and that CEOs' decisions to deviate from institutional norms are shaped by their incentives. We find support for our framework in the analysis of the stake taken by acquirers in 4,184 cross‐border acquisitions.
m6A RNA methylation regulators contribute to malignant progression in rectal cancer
Authors: Zhuang Jinfu , Lin Chunlin , Ye Jianxin
Published: February 2020

N6,2′‐O‐dimethyladenosine (m6A) RNA methylation, which is correlated with cancer initiation and progression, is dynamically regulated by m6A RNA methylation regulators, including writers, erasers, and readers. Two subgroups of rectal cancer, including cluster1 and cluster2, were identified based on consensus clustering to m6A RNA methylation regulators. A protein–protein interaction network was constructed and hub genes were identified. The results demonstrated that the expression of WTAP was significantly associated with YTHDC1 and YTHDF2. The principal component analysis was used to compare the transcriptional profile between cluster1 and cluster2 subgroups. By using two identified m6A RNA methylation regulators, we constructed a risk signature to predict the survival outcomes of rectal cancer. The results revealed that YTHDC2 and YTHDF2 were protective genes with HR < 1. The coefficients obtained from the least absolute shrinkage and selection operator algorithm were used to calculate the risk score. Patients were then divided into low‐ and high‐risk groups based on the median risk score. The survival analysis demonstrated that there were significant differences in overall survival between these two groups (p < .05). The results of the univariate analysis showed that the risk score, AJCC stage, M stage, and age were associated with overall survival. The results of the multivariate Cox regression analysis showed that the risk score and age were still significantly associated with the overall survival (p < .05). To conclude, m6A RNA methylation regulators can be regarded as potentially useful biomarkers for predicting the prognosis and designing a treatment strategy in rectal cancer.
Long‐term effects of grazing management and buffer strips on phosphorus runoff from pastures fertilized with poultry litter
Authors: Anderson Kelsey R. , Moore Philip A. , Pilon Cristiane , Martin Jerry W. , Pote Dan. H. , Owens Phillip R. , Ashworth Amanda J. , Miller David M. , DeLaune Paul B.
Published: February 2020

Phosphorus (P) runoff from pastures can cause accelerated eutrophication of surface waters. However, few long‐term studies have been conducted on the effects of best management practices, such as rotational grazing and/or buffer strips on P losses from pastures. The objective of this study was to evaluate the long‐term effects of grazing management and buffer strips on P runoff from pastures receiving annual (5.6 Mg ha−1) poultry litter applications. A 14‐yr study was conducted on 15 small watersheds (0.14 ha) with five treatments: hayed (H), continuously grazed (CG), rotationally grazed (R), rotationally grazed with an unfertilized buffer strip (RB), and rotationally grazed with an unfertilized fenced riparian buffer (RBR). Runoff samples were collected using automatic samplers during runoff events. Average annual runoff volumes from H (40 mm yr−1) and RBR (48 mm yr−1) were lower than CG and RB, which were both 65 mm yr−1, and from R (67 mm yr−1). Rotational grazing alone did not reduce P loads compared with continuous grazing (1.88 and 1.71 kg P ha−1 for R and CG, respectively). However, compared with CG, total P losses from RB pastures were reduced 36% with unfertilized buffer strips (1.21 kg P ha−1), 60% in RBR watersheds with unfertilized fenced riparian buffer strips (0.74 kg P ha−1), and 49% by converting pastures to hayfields (0.97 kg P ha−1). Hence, the use of unfertilized buffer strips, unfertilized fenced riparian buffer strips, or converting pastures to hayfields are effective best management practices for reducing P runoff in U.S. pasture systems.
Dynamics of rainfall extremes over India: A new perspective
Authors: Sooraj KP , Terray Pascal , Shilin Anokha , Mujumdar Milind
Published: February 2020

A comprehensive analysis of the role of Indo‐Pakistan arid region (IPAR) in modulating the boreal summer heavy extreme rainfall events over monsoon core zone (MCZ over Indian subcontinent) at subseasonal to daily time scales is presented. The objective is to bring new perspectives on the dynamics of such rainfall extremes. Time‐lagged composite analysis shows the clustering of Monsoon Intra‐Seasonal Oscillation with monsoon rainfall daily extremes. However, our results additionally bring out the distinct role of surface thermal forcing and moist processes over IPAR as another potential and significant precursor, 16–10 days in advance, causing monsoon rainfall daily extremes over MCZ. Further analysis reveals that the warming over IPAR is initially found in the northern part of the domain, 20–15 days before the rainfall events over MCZ and is triggered by subtropical‐midlatitude interactions characterized by the intrusion of a midlatitude (i.e., Eurasian) atmospheric wave train into the Asian domain. Our analysis further reveals strong moist static energy (MSE) build‐up over the IPAR 12 days in advance, which is initially dominated by anomalous warming in the lower atmosphere, but with an incremental contribution of low‐level specific humidity as we moved forward in time towards the rainfall event. Hydrodynamic‐longwave radiative teleconnections are the primary mechanism for the persistence of the surface warming and MSE buildup over IPAR after the initial intrusion of the Eurasian wave train. The persistent warming over IPAR reinforces the land‐sea contrast between the Middle East and western equatorial Indian Ocean to its south, and this subsequently leads to pressure anomalies and monsoon circulation changes through geostrophic wind adjustment, thus enhancing westerlies over Arabian Sea. All these factors lead to the development of a gigantic monsoon trough over central India thus causing the rainfall extremes over MCZ through the genesis of synoptic vortices.
Standoff Raman spectroscopy for future Europa Lander missions
Authors: Sharma S.K. , Porter J.N. , Misra A.K. , Acosta‐Maeda T.E. , Angel S.M. , McKay C.P.
Published: February 2020

Near Infrared Mapping Spectrograph data from the Galileo spacecraft and cryogenic laboratory reflectance measurements on hydrated compounds identified the presence of mixtures of hydrous magnesium sulfate, sulfuric acid, and hydrogen peroxide on the surface of Europa. Standoff Raman spectroscopy is ideally suited for exploring terrestrial Europa analog sites and Europa because of its ability to unambiguously identify minerals, organic compounds, and biomarkers inside ice. In the present work, we evaluated the performance of a standoff Raman system at various distances by measuring Raman spectra of hydrogen peroxide, sulfuric acid, and hydrous sulfate minerals, which are predicted to be present on Europa's surface. To simulate Europa's surface environment, Raman spectra of MgSO4·7H2O, FeSO4·7H2O, gypsum (CaSO4·2H2O), dry ice (CO2‐ice), and polycyclic aromatic hydrocarbons (PAHs) naphthalene and anthracene inside crushed H2O‐ice, shaved H2O‐ice, and a clear H2O‐ice block have also been measured. The PAHs were selected in this study because of their presence in the interstellar medium, comets, and meteorites. The results show that it will be possible to map out the non‐ice components on the surface and subsurface of Europa analog sites and Europa up to a distance of 120 m from a static lander and to a depth of ~10 cm inside ice.

We have evaluated the performance of a standoff Raman system at various distances by measuring Raman spectra of hydrogen peroxide, sulfuric acid, and hydrous sulfate minerals, which are predicted to be present on Europas surface. To simulate Europas surface environment, Raman spectra of MgSO4·7H2O, FeSO4·7H2O, gypsum (CaSO4·2H2O), dry ice (CO2‐ice), and polycyclic aromatic hydrocarbons (PAHs) naphthalene and anthracene inside crushed H2O‐ice, shaved H2O‐ice, and H2O‐ice block have been measured.
Simultaneous extraction and purification of fucoxanthin from Tisochrysis lutea microalgae using compressed fluids
Authors: Gallego Rocío , Tardif Charles , Parreira Celina , Guerra Tiago , Alves Maria João , Ibáñez Elena , Herrero Miguel
Published: February 2020

The marine microalga Tisochrysis lutea, a Haptophyta with a thin cell wall and currently used mainly in aquaculture is a potential source of several bioactive compounds of interest such as carotenoids. In the present study, the simultaneous extraction and purification of fucoxanthin, the main carotenoid from T. lutea, was optimized using pressurized fluid extraction followed by in‐cell purification. An experimental design was employed to maximize carotenoids’ extraction; the experimental factors chosen were: (i) percentage of ethanol/ethyl acetate (0–100 %), (ii) temperature (40–150°C), and (iii) number of static extraction cycles (1–3). The maximum carotenoids’ recovery, mainly fucoxanthin, was obtained with pure ethyl acetate at 40°C using one extraction cycle, achieving values of 132.8 mg of carotenoids per gram of extract. Once the optimum extraction conditions were confirmed, in‐cell purification strategies using different adsorbents were developed to obtain fucoxanthin‐enriched extracts. Activated charcoal showed potential retention of chlorophylls allowing an effective purification of fucoxanthin in the obtained extracts. Chemical characterization of extracts was carried out by reversed‐phase high‐performance liquid chromatography with diode array detection. Therefore, a selective fractionation of high value compounds was achieved using the proposed green downstream platform based on the use of compressed fluids.
Knowledge hiding in a buyer‐supplier relationship: A pilot study
Authors: Butt Atif S. , Ahmad Ahmad B. , Shah Syed Hamad Hassan
Published: February 2020

Knowledge hiding has been the topic of some research in supply chains in the last few years. These studies either identify antecedents of knowledge hiding or its negative consequences. However, studies pertaining to how knowledge hiding adversely affect buyer–supplier relationships are scant. Based on an initial pilot study comprising six semistructured with managers engaged in the process of buying and selling products and services, our results unveil three factors (lack of interpersonal trust, mutual loyalty, and limited interaction), which affect business relationship between managers of buying and supplying firms, when they hide knowledge from each other. This article concludes by discussing its initial contributions to theory. Finally, study limitations and future research direction are articulated.
Recent Advancements in Using Polymers for Intestinal Mucoadhesion and Mucopenetration
Authors: Taipaleenmäki Essi , Städler Brigitte
Published: February 2020

Oral administration of actives is the most desired form of delivery, but the formulations need to overcome a variety of barriers including the intestinal mucus. This feature article summarizes the developments from the past 2–3 years in this context focusing on polymer‐based formulations. The progress in assembling mucopenetrating nanoparticles is outlined considering coatings using noninteracting polymers as well as virus‐like particles and charge‐shifting particles. Next, polymers and their modification to enhance mucoadhesion are discussed, followed by providing examples of double‐encapsulation systems that aim to combine mucopenetration with mucoadhesion in the same formulation. Finally, a short outlook is provided highlighting a few of the most pressing challenges to address.
Habitat Associations and Co-Occurrence Patterns of Two Estuarine-Dependent Predatory Fishes
Authors: Livernois Mariah C. , Powers Sean P. , Albins Mark A. , Mareska John F.
Published: February 2020

Estuarine-dependent fishes experience a wide range of environmental conditions, and most species exhibit distinct associations with particular habitats. However, similar species or multiple conspecifics often overlap spatiotemporally, which can result in ecological interactions that have consequences for behaviors that can shape the structure and function of ecosystems. We used a long-term gill-net data set (2001–2015) to investigate the habitat associations and co-occurrence patterns of two estuarine-dependent predatory fishes, Red Drum Sciaenops ocellatus and Spotted Seatrout Cynoscion nebulosus, in coastal Alabama, USA. Both species were associated with similar environmental conditions, primarily low dissolved oxygen and low salinity, especially when temperature was low. However, differences emerged between the species with respect to the effects of interacting environmental variables on their habitat use patterns, which were likely driven by physiological, biological, and ecological dissimilarities between them. Concerning their biogenic habitat use, extensive submerged aquatic vegetation (SAV) was an important habitat for both species, but Spotted Seatrout appeared to prefer high-salinity SAV beds, while Red Drum associated with SAV regardless of salinity. Spotted Seatrout were associated with extensive emergent marsh edges, and the positive relationship between Red Drum and SAV was diminished when marsh edge was abundant. Co-occurrence was observed primarily in habitats with which both species were associated, most frequently in shallow, prey-rich marsh edges and high-salinity seagrass beds. These observed habitat use patterns elucidate the subtle differences in resource use that allow these species to coexist and suggest potential areas where interactions between them may shape their roles as predators.
Blow‐up of solution for beam equation with delay and dynamic boundary conditions
Authors: Zhang Yajing , Liu Xiaoyan
Published: February 2020

In this paper, we consider an elastic beam equation with delay, source term, and boundary conditions together with some suitable initial data. Using the Faedo‐Galerkin approximation and some estimates, we get the local existence of solution. Moreover, we obtain the finite time blow‐up of solution by constructing suitable Lyapunov functionals.
Recovering local equilibrium from three‐dimensional compatible finite element solutions
Authors: Moitinho de Almeida J. P. , Maunder E. A. W.
Published: February 2020

We study the application to compressible and incompressible three‐dimensional elasticity problems of the technique that we proposed in 2009 for the recovery of equilibrated stresses from compatible finite element solutions. The case of finite elements with linear displacement approximations, for which the partitioned systems of loads are not initially balanced in terms of rotational equilibrium, addressed in 2012, is also considered. The article includes a presentation of the implementation details, a study of the convergence in terms of the energy of the error, and a characterization of the solutions obtained.
Plasma lipid peroxidation and antioxidant status in patients with oral precancerous lesions and oral cancer
Authors: Shahi Yadvendra , Samadi Fahad M. , Mukherjee Sayali
Published: February 2020

Objective

Oral precancerous lesions like oral leukoplakia and oral submucosal fibrosis are very common in north Indian population which often leads to oral squamous cell carcinoma. Chewing of tobacco, pan masala, and betel nut is very common among north Indian women. Reactive oxygen species (ROS) generation is an important outcome of this habit. Imbalance between ROS and antioxidants leads to oxidative stress. The aim of our study was to determine the level of antioxidants in oral precancerous lesions and oral cancer to predict disease susceptibility.

Method

The study group consisted of 120 subjects among which 25 were with histopathologically confirmed oral cancer, 50 with histopathologically confirmed oral precancerous lesions, and 45 were healthy controls. Blood samples were collected for the evaluation of reduced glutathione (GSH) and antioxidant enzymes, catalase, superoxide dismutase (SOD), glutathione reductase (GR) and oxidative stress markers like malondialdehyde (MDA) and nitrite.

Result

Results demonstrated a decrease in antioxidant enzymes such as catalase, SOD, and GR in oral precancerous lesion and oral cancer from that of healthy control. An increase in reduced glutathione concentration was observed in oral precancerous lesion and oral cancer as compared to healthy control. Malondialdehyde level was increased significantly in oral cancer. Increase in nitrite concentration was not statistically significant in oral precancerous lesion and oral cancer patients as compared to control.

Conclusion

Oxidative stress and antioxidants have been found to be important indicators in oral cancer and in pre‐malignant lesions which may predict susceptibility of development of oral cancer.
Mechanical properties of electrospun nanofiber reinforced/interleaved epoxy matrix composites—A review
Authors: Shakil Usaid A. , Hassan Shukur B. A. , Yahya Mohd Y. , Nauman Saad
Published: February 2020

Electrospinning has by far proved to be the most successful method to spin high aspect and surface area to volume ratio nanofiber for multidisciplinary applications. Its application, however, as reinforcement in fiber reinforced polymer matrix composites (FRPC's) started from interlaminar fracture toughness improvement through interleaving. Since then, its usage both in short fiber and nonwoven mat formation has been phenomenally increased to tailor mechanical properties. This review paper focuses on application of nanofiber in multiscale reinforced epoxy matrix composites for mechanical performance. After a brief overview of electrospinning and spinning parameters, it presents a case for nanofiber as reinforcement with attendant mechanisms to develop insight into nanocomposite performance. Next, it summarizes and shares findings of studies, carried out in last 10 years, seeking to enhance tensile, flexural, interlaminar toughness, impact, and fatigue properties of epoxy composites through electrospun nanofiber reinforcement. Finally, it presents a perspective to gain headways in nanofiber reinforced FRPC's research through a variety of processing and material variables.
Fluorescent reporters for functional analysis in rice leaves
Authors: Luginbuehl Leonie H. , El‐Sharnouby Sherif , Wang Na , Hibberd Julian M.
Published: February 2020

Fluorescent reporters have facilitated non‐invasive imaging in multiple plant species and thus allowed the analysis of processes ranging from gene expression and protein localization to cellular patterning. However, in rice, a globally important crop and model species, there are relatively few reports of fluorescent proteins being used in leaves. Fluorescence imaging is particularly difficult in the rice leaf blade, likely due to a high degree of light scattering in this tissue. To address this, we investigated approaches to improve deep imaging in mature rice leaf blades. We found that ClearSee treatment, which has previously been used to visualize fluorescent reporters in whole tissues of plants, led to improved imaging in rice. Removing epidermal and subtending mesophyll cell layers was faster than ClearSee and also reduced light scattering such that imaging of fluorescent proteins in deeper leaf layers was possible. To expand the range of fluorescent proteins suitable for imaging in rice, we screened twelve whose spectral profiles spanned most of the visible spectrum. This identified five proteins (mTurquoise2, mNeonGreen, mClover3, mKOκ, and tdTomato) that are robustly expressed and detectable in mesophyll cells of stably transformed plants. Using microparticle bombardment, we show that mTurquoise2 and mNeonGreen can be used for simultaneous multicolor imaging of different subcellular compartments. Overall, we conclude that mTurquoise2, mNeonGreen, mClover3, mKOκ, and tdTomato are suitable for high‐resolution live imaging of rice leaves, both after transient and stable transformation. Along with the rapid microparticle bombardment method, which allows transient transformation of major cell types in the leaf blade, these fluorescent reporters should greatly facilitate the analysis of gene expression and cell biology in rice.
Low Static and Dynamic On‐Resistance with High Figure of Merit in AlGaN/GaN High Electron Mobility Transistors on Chemical Vapor Deposited Diamond
Authors: Ranjan Kumud , Sandupatla Abhinay , Arulkumaran Subramaniam , Ng Geok Ing
Published: February 2020

AlGaN/GaN high electron mobility transistors (HEMTs) on chemical vapor deposited (CVD) diamond with different gate–drain spacings (Lgd) are fabricated, and off‐state breakdown voltage (BVgd) along with a dynamic specific on‐resistance (Dyn.‐Ron,sp) is measured. Ron,sp is obtained in the range of 0.32–0.98 mΩ cm2 for HEMTs with Lgd of 2–8 μm. The HEMTs exhibit a BVgd of 415 V (Lgd = 8 μm) with a maximum lateral breakdown strength of 0.72 MV cm−1. The power device figure of merit (FOM) of ≈0.18 GW cm−2 is obtained from HEMTs with Lgd of 8 μm. The HEMTs exhibit about 60% of higher FOM when compared with the reported HEMTs on CVD diamond (≈0.11 GW cm−2). This is mainly due to the improvement of Ron,sp through the reduction of contact resistance (Rc) and sheet resistance (Rsh). The Dyn.‐Ron,sp is estimated from pulsed (pulse width/period = 200 ns/1 ms) ID–VD characteristics, which is comparable with the static Ron,sp. These improved results of the fabricated AlGaN/GaN HEMTs on CVD diamond make it a promising candidate for high‐voltage power switching device applications.
Optimal Composition of ZnO/WO3 Composite Nanoparticle Gas Sensors
Authors: Hyun Soong Keun , Nam Bumhee , Ko Tae Kyung , Lee Chongmu , Choi Seung Bok , Lee Wan In
Published: February 2020

Herein, the effect of the ZnO/WO3 molar ratio on the response of ZnO/WO3 composite nanoparticle (NP) sensors to CO is reported. For this purpose, NP samples with ZnO/WO3 molar ratios of 2:8, 4:6, 5:5, 6:4, and 8:2 are prepared using wet chemical methods. The strongest response to 200 ppm CO is obtained by the 6:4 ZnO/WO3 composite NP sensor, which differs from previous reports, in which a ZnO/WO3 composite NP sensor with a molar ratio of 5:5 shows the strongest response to gases. The origin of this difference is explained in detail. The response of the 6:4 ZnO/WO3 composite NP sensor to 200 ppm of CO is ≈30 times stronger than that of the 8:2 ZnO/WO3 composite NP sensor. The 6:4 ZnO/WO3 composite NP sensor also shows the shortest response and recovery time among the five ZnO/WO3 composite NP sensors with different molar ratios. The underlying mechanism for the enhanced response of the ZnO/WO3 composite NP sensors to CO compared with that of the pure ZnO NP sensor is also discussed in detail.
Emerging Applications of III‐Nitride Nanocrystals
Authors: Liu Xianhe , Chowdhury Faqrul A. , Vanka Srinivas , Chu Sheng , Mi Zetian
Published: February 2020

Recently, significant progress has been made in III‐nitride nanocrystals. They exhibit unique structural, electronic, optical, and photocatalytic properties, and have emerged as a functional platform to realize high‐performance optoelectronic, electronic, quantum, and solar energy devices. Compared with conventional III‐nitride epilayers and quantum wells, dislocation‐free III‐nitride nanocrystals can, in principle, be achieved on lattice mismatched foreign substrates due to the efficient surface strain relaxation. In this Feature Article, the authors discuss the epitaxy, characteristics, and some emerging device applications of III‐nitride nanocrystals grown by plasma‐assisted molecular beam epitaxy.
Delay compensated control of the Stefan problem and robustness to delay mismatch
Authors: Koga Shumon , Bresch‐Pietri Delphine , Krstic Miroslav
Published: February 2020

This paper presents a control design for the one‐phase Stefan problem under actuator delay via a backstepping method. The Stefan problem represents a liquid‐solid phase change phenomenon which describes the time evolution of a material's temperature profile and the interface position. The actuator delay is modeled by a first‐order hyperbolic partial differential equation (PDE), resulting in a cascaded transport‐diffusion PDE system defined on a time‐varying spatial domain described by an ordinary differential equation (ODE). Two nonlinear backstepping transformations are utilized for the control design. The setpoint restriction is given to guarantee a physical constraint on the proposed controller for the melting process. This constraint ensures the exponential convergence of the moving interface to a setpoint and the exponential stability of the temperature equilibrium profile and the delayed controller in the norm. Furthermore, robustness analysis with respect to the delay mismatch between the plant and the controller is studied, which provides analogous results to the exact compensation by restricting the control gain.
On the determinants of Uber accessibility and its spatial distribution: Evidence from Uber in Philadelphia
Authors: Shokoohyar Sina , Sobhani Anae , Ramezanpour Nargesi Saeed R.
Published: February 2020

This study investigates the impact of socioeconomics and demographic factors (e.g., population density, minority rate, age, gender, education, wealth, and crime) and transportation infrastructure (e.g., walk score, transit score, and bike score) on the accessibility of Uber in the city of Philadelphia. K‐means clustering is applied for initial data exploration. Based on the spatial model selection diagnostic tests, we developed maximum likelihood spatial lag models with queen contiguity spatial weight matrix. The results show that Uber accessibility is not balanced in different neighborhoods in Philadelphia. Uber is more accessible in denser areas with the high male population, better public transportation access and less access to amenities in the walkable distances. Moreover, we observed that Uber is more accessible in areas with a high crime rate. This observation shows that Uber has made it easier to get out of high crime rate areas. Finally, contribution in the literature on accessibility in ride‐sourcing networks is discussed. Findings are additionally used to provide managerial implications to mitigate discrimination in ride‐sourcing platforms.

This article is categorized under:

Application Areas > Industry Specific Applications

Algorithmic Development > Spatial and Temporal Data Mining

Commercial, Legal, and Ethical Issues > Social Considerations
SrIrIn6 – An Intergrowth of SrIrIn4 with Indium Slabs
Authors: Engelbert Simon , Kösters Jutta , Pöttgen Rainer
Published: February 2020

The indium‐rich intermetallic compound SrIrIn6 was synthesized from the elements in a sealed tantalum ampoule at 1173 K, followed by slow cooling for crystal growth. SrIrIn6 crystallizes with a new structure type which was characterized by X‐ray powder and single crystal diffraction: Pmma, a = 852.34(2), b = 434.54(5), c = 1059.18(6) pm, wR2 = 0.0178, 884 F2 values, and 32 variables. The SrIrIn6 structure shows two basic building units: (i) Ir@In9 tricapped trigonal prisms (261–292 pm Ir–In) and (ii) distorted bcc In@In8 cubes (301 to 329 pm In–In). The strontium cations fill cages within the complex three‐dimensional [IrIn6] network and have coordination number 13 (Sr@In13) in form of a tricapped pentagonal prism. The SrIrIn6 structure can be described as a simple intergrowth variant of SrIrIn4 (LaCoAl4 type) with indium slabs. The crystal chemical similarities with the structures of SrIrIn4, SrIr2In8 and Eu3Ir2In15 are discussed.
Infrared spectral characterization of the molecular wood decay in terms of age
Authors: Tintner J. , Spangl B. , Reiter F. , Smidt E. , Grabner M.
Published: February 2020

This study presents a new chronometric method for the dating of wood. The clock used is the chemical breakdown of specific parts, such as the acetyl groups of the hemicelluloses. The presented prediction models cover a maximum of 3000 years and include old living trees, construction wood and cold waterlogged wood. Any other preservation conditions are not covered by these models. Under these conditions, abiotic factors dominate and the contribution of microbial decay is negligible. This is a pre-requisite for the application of the present models. Brittle parts of the wood cannot be dated. Infrared spectroscopy was applied to detect the molecular changes over time. Currently, four models are available for Norway spruce, European larch, oak, and silver fir.