bluuebunny/crossref_metadata_2025_split huggingface dataset:
Graphene/silver nanoparticles‐based surface‐enhanced Raman spectroscopy detection platforms: Application in the study of DNA molecules at low pH
Authors: Muntean Cristina M. , Dina Nicoleta E. , Coroş Maria , Toşa Nicoleta , Turza Alexandru I. , Dan Monica 
Published: August 2019

AbstractThe aim of this work is to develop a surface‐enhanced Raman spectroscopy (SERS)‐active platform based on a mixture of graphene/Ag nanocomposite and a silver colloid for biomedical applications and to test it in the case of DNA molecules at low pH. Graphene/silver nanocomposites were synthesized by the reduction process and were characterized by transmission electron microscopy, X‐ray powder diffraction patterns, and thermogravimetric analysis. The following graphene/Ag composites were prepared: (a) “thermally reduced graphene oxide” (TRGO), containing about 2–3% silver nanoparticles (AgNPs); (b) TRGO 1 (graphene with crowded AgNPs 20%); and (c) TRGO 2 (graphene with ordered AgNPs 20%). Different mixtures of these systems with a silver colloid were tested not only by ultraviolet‐visible spectrophotometry but also by SERS in the presence of the test substance crystal violet. Moreover, the time stability of the mixtures of graphene/AgNPs composite (TRGO 1) with the silver colloid was tested for crystal violet. Based on these results, the platform with the best SERS enhancement properties was selected for DNA analyses at low pH values. Chemical stability under acidic conditions has been found for nucleic acid systems, in the presence of graphene/crowded AgNPs 20% and silver colloid. This chemical stability has been discussed considering a hydracid catalyzed electrophilic hydration reaction mechanism characteristic to the trans‐1,3‐butadiene‐type building moieties from graphene.
Semiautomatic Fetal Intelligent Navigation Echocardiography Has the Potential to Aid Cardiac Evaluations Even in Less Experienced Hands
Authors: Gembicki Michael , Hartge David R. , Dracopoulos Christoph , Weichert Jan 
Published: August 2019

ObjectivesTo investigate the interobserver and intraobserver variability and corresponding learning curve in a semiautomatic approach for a standardized assessment of the fetal heart (fetal intelligent navigation echocardiography [FINE]).MethodsA total of 30 stored spatiotemporal image correlation volume data sets of second‐trimester fetuses were evaluated by 3 physicians with different levels of expertise in fetal echocardiography by using the FINE approach. Data were analyzed regarding the examination time and proper reconstruction of the diagnostic cardiac planes. The completions and numbers of correct depictions of all diagnostic planes were evaluated by a blinded expert (time t0). To determine interobserver and intraobserver variability, the volumes were reassessed after a 4‐week training interval (time t1).ResultsAll operators were able to perform the investigation on all 30 volumes. At t0, the interobserver variability between the beginner and both the advanced (P = .0013) and expert (P < .0001) examiners was high. Focusing on intraobserver variability at t1, the beginner showed a marked improvement (P = .0087), whereas in advanced and expert hands, no further improvement regarding proper achievement of all diagnostic planes could be noticed (P > .999; P = .8383). The beginner also showed improvement in the mean investigation time (t0, 82.8 seconds; t1, 73.4 seconds; P = .0895); nevertheless, the advanced and expert examiners were faster in completing the examination (t1, advanced, 20.9 seconds; expert, 28.3 seconds; each P < .0001).ConclusionsBased on our results, the FINE technique is a reliable and easily learned method. The use of this semiautomatic work flow–based approach supports evaluation of the fetal heart in a standardized and time‐saving manner. A semiautomatic evaluation of the fetal heart might be useful in facilitating the detection of fetal cardiac anomalies.
Computed tomography performance in predicting extranodal extension in HPV‐positive oropharynx cancer
Authors: Faraji Farhoud , Aygun Nafi , Coquia Stephanie F. , Gourin Christine G. , Tan Marietta , Rooper Lisa M. , Eisele David W. , Fakhry Carole 
Published: August 2019

ObjectivesTo evaluate the performance characteristics of seven predetermined imaging features on pretreatment computed tomography (CT) in identifying extranodal extension (ENE) in cervical lymph node metastases from human papillomavirus‐positive oropharyngeal carcinoma (HPV‐OPC).Study DesignRetrospective study.MethodsSeventy‐three patients with HPV‐OPC who underwent primary surgery and cervical lymph node dissection were included. Preoperative contrast‐enhanced CT (cCT) imaging was evaluated by two radiologists blinded to pathological results. Each cCT was scored for seven imaging features of interest: 1) indistinct capsular contours, 2) irregular nodal margins, 3) perinodal fat stranding, 4) perinodal fat planes, 5) nodal necrosis, 6) intranodal cysts, and 7) nodal matting. Logistic regression was employed to determine radiologist‐specific odds ratios (OR) of predicting ENE for each imaging feature and radiologist‐specific receiver operating characteristics (sensitivity [Sn], specificity [Sp], area under the curve [AUC], positive predictive value [PPV], negative predictive value [NPV]) for each imaging feature.ResultsThirty‐two (44%) patients had ENE‐positive lymph nodes. The presence of irregular margins (ORA = 12.3, 95% confidence interval [CI]A = 2.3–65.9; ORB = 7.0, 95% CIB = 1.4–36.3) and absence of perinodal fat plane (ORA = 6.8, 95% CIA = 2.0–23.3; ORB = 14.2, 95% CIB = 1.7–120.5) were significantly associated with ENE for each radiologist. Irregular nodal margin status was most specific for ENE (SnA = 45%, SpA = 94%, AUCA = 69%, PPVA = 82%, NPVA = 73%; SnB = 28%, SpB = 95%, AUCB = 61%, PPVB = 80%, NPVB = 64%). Absence of perinodal fat plane was most sensitive for ENE (SnA = 87%, SpA = 50%, AUCA = 69%, PPVA = 59%, NPVA = 62%; SnB = 96%, SpB = 34%, AUCB = 65%, PPVB = 53%, NPVB = 63%).ConclusionsOf the seven imaging features hypothesized to be associated with ENE‐status, the presence of irregular nodal margins and absence of perinodal fat plane were the most specific and sensitive features, respectively.Level of Evidence4 Laryngoscope, 130:1479–1486, 2020
Elective Neck Dissection Versus Observation in Early‐Stage (cT1/T2N0) Oral Squamous Cell Carcinoma
Authors: Liu Jin‐Yong , Chen Chieh‐Feng , Bai Chyi‐Huey 
Published: August 2019

ObjectivesWhether to perform elective neck dissection (END) or apply the observation (OBS) policy in patients with early‐stage oral squamous cell carcinoma (OSCC) without clinical evidence of cervical lymph node metastasis (cT1/T2N0) remains uncertain. The two most recent meta‐analyses include many studies published before the widespread availability of CT scanning in the 1990s. With the rapid advancement in imaging studies since 1990, the early clinical detection of cervical node metastasis has become more reliable without the need for END or pathological staging. Thus, we conducted a systematic review and meta‐analysis of studies comparing survival outcomes between END and OBS in patients with cT1/T2N0 OSCC.MethodsWe performed a systematic search of MEDLINE, PubMed, and Scopus for retrospective and prospective studies published between January 1, 1990, and January 1, 2018, comparing clinical outcomes between END and OBS in patients with cT1/T2N0 OSCC. Information on population characteristics, study design, overall survival (OS), disease‐specific survival (DSS), and disease‐free survival (DFS) was extracted and estimated. Effect measures for outcomes were hazard ratios (HRs) and 95% confidence intervals (CIs).ResultsThirteen retrospective and two prospective randomized studies (3,158 patients) met the inclusion criteria. Compared to OBS, END failed to significantly improve OS (HR, 1.02; 95% CI, 0.95–1.09; P = .77; fixed‐effects model), DSS (HR, 1.07; CI, 1.02–1.13; P = .31; fixed‐effects model), and DFS (HR, 0.86; CI, 0.72–1.01; P = .12; random‐effects model).ConclusionsOur findings indicate that in patients with cT1T2N0 OSCC, the OBS policy can yield markedly similar OS, DSS, and DFS to those resulting from END.Level of Evidence2
Partitioning of Rumen‐Protected n‐3 and n‐6 Fatty Acids is Organ‐Specific in Growing Angus Heifers
Authors: Wolf Christina , Gredig Nicole , Ulbrich Susanne E. , Kreuzer Michael , Berard Joel , Giller Katrin 
Published: August 2019

AbstractDietary polyunsaturated fatty acids (PUFA), especially n‐3 and n‐6 fatty acids (FA), play an important role in the regulation of FA metabolism in all mammals. However, FA metabolism differs between different organs, suggesting a distinct partitioning of highly relevant FA. For the present study in cattle, a novel technology was applied to overcome rumen biohydrogenation of dietary unsaturated FA. Angus heifers were fed a straw‐based diet supplemented for 8 weeks with 450 g/day of rumen‐protected oil, either from fish (FO) or sunflower (SO). The FA composition in blood and five important organs, namely heart, kidney, liver, lung, and spleen, was examined. In blood, proportions of polyunsaturated FA were increased by supplementing FO compared to SO. The largest increase of eicosapentaenoic acid (EPA) proportion was found with FO instead of SO in the kidney, the lowest in the lung. Docosahexaenoic acid (DHA) was increased more in the liver than in kidney, lung, and spleen. The heart incorporated seven times more EPA than DHA, which is more than all other organs and described here for the first time in ruminants. In addition, the heart had the highest proportions of α‐linolenic acid (18:3n‐3) and linoleic acid (18:2n‐6) of all organs. The proportions of polyunsaturated FA in the lung and spleen were exceptionally low compared to heart, liver, and kidney. In conclusion, it was shown that the response to FO in the distribution of dietary n‐3 FA was organ‐specific while proportions of n‐6 FA were quite inert with respect to the type of oil supplemented.
Internal waves pump waters in and out of a deep coastal embayment of a large lake
Authors: Flood Bryan , Wells Mathew , Dunlop Erin , Young Joelle 
Published: August 2019

AbstractLarge internal waves are a ubiquitous feature of many thermally stratified lakes, and result in oscillating baroclinic flows that pump water into and out of deep coastal embayments. In the long, narrow, and deep Kempenfelt Bay of Lake Simcoe, we show that stratification and circulation were coupled, so that movements of the thermocline can effectively flush the embayment much faster than hydraulic residence time from river input alone. Internal currents were driven by long‐period internal waves and resulted in large horizontal excursion lengths of several kilometers, which could drive exchange of embayment waters with the main basin. If the embayments are long, wide, and deep, Coriolis forces also deflect the internal wave to follow the coastline on the right‐hand side in the direction of travel as a Kelvin‐type wave, resulting in a net cyclonic circulation in the embayment. This residual counterclockwise flow further facilitated flushing of Kempenfelt Bay. For the summer of 2015, we estimate that forced and free internal wave dynamics alone resulted in a seasonally averaged flushing timescale as short as 17 ± 6 d for the surface mixed layer, and of 13.5 ± 5 d for the hypolimnetic waters of Kempenfelt Bay. Kempenfelt Bay is representative of many long, deep, and narrow embayments found in the Laurentian Great Lakes and arctic fjords. The exchange processes investigated here are relevant for determining the dynamics of water quality parameters used as indicators to evaluate lake health and fish habitat.
Under‐ice salinity transport in low‐salinity waterbodies
Authors: Olsthoorn Jason , Bluteau Cynthia E. , Lawrence Gregory A. 
Published: August 2019

AbstractIn cold and temperate climates, ice typically covers the surface of waterbodies during winter. Many of these systems are also weakly saline where, unlike seawater, the temperature of maximum density, , is higher than its freezing temperature, . This feature of the equation of state results in a stable temperature stratification when surface waters cool below . Conversely, salts excluded from the growing ice can destabilize the underlying water. Previous laboratory and field experiments demonstrated that excluded salts generate localized overturning and downward transport of salt, despite the persistence of a stable temperature gradient. Those experiments were not able to determine the processes responsible for this transport. Here, we use direct numerical simulations to visualize and characterize the plumes generated when ice excludes salt into a stable temperature gradient. We restrict our analysis to times much earlier than the diffusion timescale of temperature over the domain. We define a mass flux parameter ℜ that considers the strength of the reverse‐temperature stratification relative to the rate of salt exclusion. We identify two types of plumes whose characteristics depend mainly on
ℜ: double‐diffusive salt‐fingering plumes and convective plumes. The former encourages transport of salt to the bottom without significantly mixing the temperature stratification, while the latter tends to mix the water column. We apply a scaled mass flux parameter to published laboratory and field observations in low‐salinity systems. These limited observations compare favorably with our numerical analysis.
Water motion and vegetation control the pH dynamics in seagrass‐dominated bays
Authors: James Rebecca K. , van Katwijk Marieke M. , van Tussenbroek Brigitta I. , van der Heide Tjisse , Dijkstra Henk A. , van Westen René M. , Pietrzak Julie D. , Candy Adam S. , Klees Roland , Riva Riccardo E. M. , Slobbe Cornelis D. , Katsman Caroline A. , Herman Peter M. J. , Bouma Tjeerd J. 
Published: August 2019

AbstractGlobal oceanic pH is lowering, which is causing great concern for the natural functioning of marine ecosystems. Current pH predictions are based on open ocean models; however, coastal zones are dynamic systems with seawater pH fluctuating temporally and spatially. To understand how coastal ecosystems will respond in the future, we first need to quantify the extent that local processes influence the pH of coastal zones. With this study, we show that over a single diurnal cycle, the total pH can fluctuate up to 0.2 units in a shallow seagrass‐dominated bay, driven by the photosynthesis and respiration of the vegetation. However, these biologically controlled pH fluctuations vary significantly over small distances. Monitoring conducted at neighboring sites with contrasting hydrodynamic regimes highlights how water motion controls the extent that the local pH is altered by the metabolism of vegetation. The interactive effects of hydrodynamics and vegetation were further investigated with an in situ experiment, where the hydrodynamics were constrained and thus the local water residence time was increased, displaying the counteractive effect of hydrodynamics on the pH change caused by vegetation. With this research, we provide detailed in situ evidence of the spatial variation of pH within marine ecosystems, highlighting the need to include hydrodynamic conditions when assessing the pH‐effects of vegetation, and identifying potential high‐pH refuges in a future low pH ocean.
Electromagnetic‐Dual Metasurfaces for Topological States along a 1D Interface
Authors: Bisharat Dia'aaldin J. , Sievenpiper Daniel F. 
Published: August 2019

AbstractThe discovery of topological insulators was rapidly followed by the advent of their photonic analogues, motivated by the prospect of backscattering‐immune light propagation. So far, however, implementations have mainly relied on engineering bulk modes in photonic crystals and waveguide arrays in two‐dimensional (2D) systems, which closely mimic their electronic counterparts. In addition, metamaterials‐based implementations subject to electromagnetic duality and bianisotropy conditions suffer from intricate designs and narrow operating bandwidths. Here, it is shown that symmetry‐protected topological states akin to the quantum spin‐Hall effect can be realized in a straightforward manner by coupling surface modes over metasurfaces of complementary electromagnetic responses. Specifically, stacking unit cells of such metasurfaces directly results in double Dirac cones of degenerate transverse‐electric (TE) and transverse‐magnetic (TM) modes, which break into a wide nontrivial bandgap at small interlayer separation. Consequently, the ultrathin structure supports robust gapless edge states, which are confined along a one‐dimensional (1D) line rather than a surface interface, as demonstrated at microwave frequencies by near‐field imaging. The simplicity and versatility of the proposed approach proves attractive as a tabletop platform for the study of classical topological phases, as well as for applications benefiting the compactness of metasurfaces and the potential of topological insulators.
Real‐Time In Situ Holographic Optogenetics Confocally Unraveled Sculpting Microscopy
Authors: Lerman Gilad M. , Little Justin P. , Gill Jonathan V. , Rinberg Dmitry , Shoham Shy 
Published: August 2019

AbstractTwo‐photon (2P) optogenetic stimulation is currently the only method for precise, fast, and non‐invasive cellular excitation deep inside brain tissue; it is typically combined with holographic wavefront‐shaping techniques to generate distributed light patterns and target them to multiple specific cells in the brain. During propagation in the brain, these light patterns undergo severe distortion, mainly due to scattering, which leads to a discrepancy between the desired and actual light distribution. However, despite its importance, measurement of these tissue‐induced distortions and their effects on the light patterns has yet to be demonstrated in situ. To this end, holographic optogenetics confocally unraveled sculpting (HOCUS), a system for real‐time in situ evaluation of holographic light patterns, based on confocally descanning the stimulation light's reflection from the brain, is developed. HOCUS measures both tissue and wave propagation properties and enables the real‐time measurement and correction of the dimensions and positions of holographic spots relative to neurons targeted for stimulation. It can also be used to measure tissue attenuation length, and thus should facilitate future attempts to optimize the generated hologram to pre‐compensate for tissue‐induced distortions, thereby improving the reliability of 2P holographic stimulation experiments.
Microstructural evolution and corrosion behavior of friction stir processed fine‐grained AZ80 Mg alloy
Authors: Huang Liying , Wang Kuaishe , Wang Wen , Peng Pai , Qiao Ke , Liu Qiang 
Published: August 2019

AbstractFriction stir processing (FSP) and subsequent aging heat treatment were used to modify the microstructure of AZ80 magnesium alloy. The influence of FSP and aging heat treatment on the corrosion behavior was systematically studied by using potentiodynamic polarization, immersion, and slow strain rate tensile tests. The results revealed that FSP led to grain refinement, rapid dissolution of β‐phase, and the deflection of c‐axis from transverse direction (TD) and processing direction (PD) by approximately 55° and 25°, respectively, improving the static corrosion and stress corrosion cracking (SCC) resistance. The aging heat treatment rendered a little influence on the grain size and slightly affected the grain orientation. The content of β‐phase in FSP‐5 and FSP‐24 samples was 8.1 and 21.8 wt.%, respectively. Static corrosion and SCC resistance of FSP‐5 and FSP‐24 samples were lower than those of the FSP samples. Compared with FSP‐5 sample, the amount of β‐phase and the proportion of Al2O3 increased in FSP‐24 sample, leading to enhanced static corrosion and SCC resistance. SCC behavior was controlled by anodic dissolution, whereas the presence of hydrogen accelerated the SCC.
Polyethylene–Silica Nanocomposites with the Structure of Semi‐Interpenetrating Networks
Authors: Trofimchuk Elena S. , Meshkov Ivan B. , Kandlina Margarita N. , Nikonorova Nina I. , Muzafarov Aziz M. , Malyshkina Inna A. , Moskvina Marina A. , Grabovenko Fedor I. , Volynskii Aleksandr L. 
Published: August 2019

AbstractOrganic–inorganic nanocomposites with the structure of interpenetrating or semi‐interpenetrating networks are considered as advanced materials, since they have improved thermal and mechanical properties. An alternative approach to the preparation of such hybrid systems is proposed. It is based on the synthesis of silica from the precursor of hyperbranched polyethoxysiloxane by the hydrolytic condensation reaction in the volume of pores of a polymer matrix (bulk porosity is 40 vol%) stretched via the environmental crazing mechanism. Polyethylene–silica nanocomposites with the structure of semi‐interpenetrating networks when the content of silica is not less than 20–25 wt% are obtained. These composites can undergo an additional phase separation at a temperature of 160 °C (above the melting point of polyethylene), which is accompanied by an increase in the size of the polymer phase with the formation of macrophases. At the same time, the environment (orthophosphoric acid), in which the composite is heated, fills the pores that have appeared. As a result, the content of the third component with the new functionality increases up to 50 wt%, which allowed us to impart proton‐conducting properties to the composite material and preserve its shape stability.
Traditional or behavioural? A combined decision making trial and evaluation laboratory and analytic network process approach for capital structure determinants of Turkish companies
Authors: Bank Semra , Arslantürk Çöllü Duygu , Bulut Halil Ibrahim 
Published: August 2019

AbstractThe aim of this study, following a new approach under the irrationality of managers, is to investigate the most effective determinants of capital structure decisions by combining traditional capital structure determinants with managerial‐behavioural biases. In line with this objective, considering the capital structure decision as one that employs multicriteria decision making, two of the multicriteria decision‐making methods—namely, Decision Making Trial and Evaluation Laboratory (DEMATEL) and Analytic Network Process (ANP)—are integrated into a hybrid method to analyse the interdependent relationships among traditional capital structure determinants and managerial‐behavioural biases and to prioritize them by making dual comparisons. Our findings show that managerial‐behavioural biases, not traditional capital structure determinants, are more effective in the capital structure decision and that anchoring is the most influential among managerial‐behavioural biases.
A compact feeding network with radiation contribution for X‐band marine radar antenna array applications
Authors: Wang Zhongbao , Zhou Jianhao , Wang Ya‐Nan , Zhu Zihui , Fang Shaojun , Liu Hongmei 
Published: August 2019

AbstractA compact feeding network with radiation contribution is proposed in designing microstrip patch array antenna (MPAA) for X‐band marine radar applications. The 1‐to‐4 feeding network consists of two circular‐sector patch balun, which can radiate electromagnetic wave with the same polarization of the patch array for enhancing the gain and suppressing the cross polarization. The feeding line in the series‐fed patch subarray is modified as the step‐impedance microstrip line to decrease the side‐lobe level (SLL). To verify the method, a 28‐element 9.41‐GHz MPAA with the proposed radiated feeding network is designed and fabricated. Measured results show that the impedance bandwidth is 183 MHz with a peak gain of 21.3 dBi. The SLL is 27.8 and 21.4 dB in the E‐ and H‐planes, respectively. The cross polarization is effectively reduced, which is lower than the copolarization of about 57 dB.