bluuebunny/crossref_metadata_2025 huggingface dataset:
Cardiac Structure–Function MRI in Patients After Heart Transplantation
Authors: Dolan Ryan S. , Rahsepar Amir A. , Blaisdell Julie , Lin Kai , Suwa Kenichiro , Ghafourian Kambiz , Wilcox Jane E. , Khan Sadiya S. , Vorovich Esther E. , Rich Jonathan D. , Anderson Allen S. , Yancy Clyde W. , Collins Jeremy D. , Markl Michael , Carr James C.
Published: August 2018

Background

Following heart transplantation (Tx), recipients are closely monitored using endomyocardial biopsy, which is limited by cost and invasiveness, and echocardiography, which is limited regarding detailed structural and functional evaluation.

Purpose

To test the feasibility of comprehensive structure–function cardiac MRI as a noninvasive modality to assess changes in myocardial structure and function.

Study Type

Prospective.

Subjects

MR was performed in 61 heart transplant recipients (age 47.9 ± 16.3 years, 39% female) and 14 age‐matched healthy controls (age 47.7 ± 16.7 years, 36% female).

Field Strength/Sequence

1.5T; 2D CINE steady state free precession (SSF)P imaging, T2‐mapping, pre‐ and postgadolinium contrast T1‐mapping, and tissue‐phase mapping (TPM).

Assessment

Quantification of myocardial T2 (as a measure of edema), pre‐ and post‐Gd T1 (allowing calculation of extracellular volume (ECV) to estimate interstitial expansion), and TPM‐based assessment of peak regional left ventricular (LV) velocities, dyssynchrony, and twist.

Statistical Tests

Comparisons between transplant recipients and controls were performed using independent samples t‐tests. Relationships between structural (T2, T1, ECV) and functional measures (myocardial velocities, dyssynchrony, twist) were assessed using Pearson correlation analysis.

Results

T2 and T1 were significantly elevated in transplant recipients compared to controls (global T2: 50.5 ± 3.4 msec vs. 45.2 ± 2.3 msec, P < 0.01; global T1: 1037.8 ± 48.0 msec vs. 993.8 ± 34.1 msec, P < 0.01). Systolic longitudinal function was impaired in transplant recipients compared to controls (reduced peak systolic longitudinal velocities, 2.9 ± 1.1 cm/s vs. 5.1 ± 1.2 cm/s, P < 0.01; elevated systolic longitudinal dyssynchrony, 60.2 ± 30.2 msec vs. 32.1 ± 25.1 msec, P < 0.01). Correlation analysis revealed a significant positive relationship between T2 and ECV (r = 0.45,P < 0.01). In addition, peak systolic longitudinal velocities demonstrated a significant inverse relationship with T2 (global r = –0.29, P = 0.02), and systolic radial dyssynchrony was positively associated with peak T2 and peak T1 (r = 0.26,P = 0.04; r = 0.27,P = 0.03).

Data Conclusion

MR techniques are sensitive to structural and functional differences in transplant recipients compared to controls. Structural (T2, T1) and functional (peak myocardial velocities, dyssynchrony) measures were significantly associated, suggesting a structure–function relationship of cardiac abnormalities following heart transplant.

Level of Evidence: 2

Technical Efficacy Stage: 2

J. Magn. Reson. Imaging 2019;49:678–687.
Generation and transmission equipment maintenance scheduling by transmission switching and phase shifting transformer
Authors: Behnia Hamid , Akhbari Mahdi
Published: August 2018

This paper models and investigates the incorporation of economic transmission switching (TS) into generation and transmission equipment maintenance scheduling (GTEMS) with the presence of phase shifting transformers. Adding TS and phase shifting transformer to the traditionally static transmission system makes it more flexible. The N‐1 secure GTEMS with TS problem is formulated as a mixed‐integer linear programming model. This problem is hard to solve by off‐the‐shelf commercial optimization solvers because on the one hand maintenance scheduling variables couple several time intervals together and on the other hand TS variables link normal and contingency states. A solution approach is proposed in this paper to address the problem's high computational burden, which decomposes the problem into a GTEMS subproblem and an optimal TS subproblem and solves them iteratively. The proposed model and decomposition approach are implemented on IEEE 30‐bus test system. The results demonstrate that considering TS in GTEMS alters the maintenance schedule and brings cost saving.
Clozapine impact on c‐Fos expression in mild stress preconditioned male rats exposed to a novelty stressor
Authors: Osacka Jana , Szelle Cernackova Alena , Horvathova Lubica , Majercikova Zuzana , Pirnik Zdeno , Kiss Alexander
Published: August 2018

Clozapine (CLZ) stimulates several brain areas some of them being sensitive to stress. Aim of the present study was to reveal whether 7‐day CLZ administration may: (1) activate the selected forebrain areas; (2) modulate response of these structures to a single forced swimming episode (FSW); (3) modulate response of these structures to FSW after 13‐day preconditioning with mild unpredictable stress complex (CMS). Used groups of male Wistar rats: (a) vehicle or CLZ treated for 7 days; (b) vehicle or CLZ treated for 7 days and on the 7th day exposed to FSW; (c) CMS exposed for 13 days, from the 8th day injected with vehicle or CLZ and on the 14th day exposed to FSW. Vehicle or CLZ (10 mg kg−1 day−1in 0.1% acetic acid) were administered intraperitoneally. c‐Fos quantification was performed 90 min after FSW in the medial prefrontal cortex (mPFC), dorsolateral (dLS) and ventrolateral (vLS) septum, dorsolateral (DLStr) and dorsomedial (DMStr) striatum, nucleus accumbens shell (NAc shell) and core (NAc core), and hypothalamic paraventricular nucleus (PVN). In unstressed animals CLZ increased c‐Fos expression in the mPFC, vLS, and PVN. After a single FSW, CLZ decreased the number of c‐Fos immunoreactive cells in the vLS, DMStr, NAc shell, and NAc core. In CMS rats, CLZ suppressed c‐Fos immunoreactivity in response to FSW in the PVN. Our data indicate that CLZ elicits different impact on neuronal activities in the brain areas studied and modifies the response of these structures to stress. CLZ effect seems to be affected by stress duration.
The October 1891 Cartago (Costa Rica) floods from documentary sources and 20CR data
Authors: Amador Jorge A. , Anderson María J. , Calderón Blanca , Pribyl Kathleen
Published: August 2018

This work comes to fill a fundamental gap in the history of Central American extreme climatic events by putting together qualitative and quantitative historical data and reanalysis information (the 20CR project) for the reconstruction of meteorological events associated with the floods that destroyed Cartago City in Costa Rica on October 27, 1891. This is a case study of a devastating 19th‐century disaster with profound social repercussions. Accounts, original historical documents, artistic depictions, instrumental data and photographs of the floods provide enough evidence of the severity of the meteorological system and the social dimension of the disaster. The historical information details the continuous rains, as well as the area covered by mud, trees and big rocks in the Cartago Valley due to the Reventado River flooding. Based on the above sources, the destruction of houses, roads and civil infrastructure is described, and the meteorological conditions of the period are analysed. By using documentary, instrumental and 20CR data, the potential direct or indirect effects of some tropical atmospheric systems were studied for the period October 22–29, 1891. Results indicate that the most probable cause of the rains and floods was a Caribbean “temporal,” a system that strikes the region frequently. This phenomenon, according to 20CR data, was modulated by a high‐pressure system over the Gulf of Mexico and brought abundant moisture and high winds to the region. Two women and three children were officially confirmed to have died; however, other sources imply many more victims and disappearances. The interventions by the government and local people were crucial for the restoration of the flooded part of Cartago City from the tragedy. The rains and floods left more than 120 seriously damaged or destroyed houses, and severe economic losses equivalent to potentially much more than 49 MM U.S. dollars.
Late spring soil moisture variation over the Tibetan Plateau and its influences on the plateau summer monsoon
Authors: Zhou Juan , Wen Jun , Liu Rong , Wang Xin , Xie Yan
Published: August 2018

Based on the European Centre for Medium‐Range Weather Forecasts (ECMWF) ERA‐Interim reanalysis data from 1979 to 2016, an index for Tibetan Plateau (TP) soil moisture (ITPSM), which could represent inter‐annual variation in spring soil moisture, is defined after removing the linear trend in soil moisture. The late spring soil moisture variation over the TP and its influences on the plateau summer monsoon are analysed. The results show that the TP soil moisture variation is non‐uniform, and spring soil moisture over the northeastern TP shows an increasing trend, while the western TP (especially the peripheral area) renders a significantly decreasing trend. When the ITPSM shows positive (negative) anomalies (i.e., spring soil moisture over the northeastern TP is higher (lower), soil moisture over the western TP is lower (higher) than normal), the plateau summer monsoon may be stronger (weaker). Anomalous variations in spring TP soil moisture can eventually affect the plateau summer monsoon by changing atmospheric circulation, diabatic heating, and water vapour transportation. It is found that when the ITPSM exhibits positive anomalies, diabatic heating over the centre and eastern TP is remarkably enhanced, and warm and humid moisture from the Bay of Bengal and Arabian Sea and cold air from high latitudes merge over the central and eastern TP; coupled with lower‐level convergence and upper‐level divergence, all these contribute to an increase in plateau summer monsoonal precipitation. When the ITPSM shows negative anomalies, diabatic heating over the centre and eastern TP is weakened, the anomalous cyclone to the south of the TP hinders warm and humid air flows transportation to the TP, and the anomalous anticyclone to the southeast of Lake Baikal weakens cold air to the south; coupled with weakened convergence and upwards motion, these factors all lead to a decrease in plateau summer monsoonal precipitation.
A climatology of the winter low‐level jet over the Red Sea
Authors: Samman Ahmad E. , Gallus William A.
Published: August 2018

This study presents the first climatology of the low‐level jet (LLJ) over the southern part of the Red Sea during the winter season. ERA‐Interim pressure levels with 25 hPa vertical resolution were analysed for a 10‐year period from 2006 to 2015. The jet was found to be a relatively frequent phenomenon, occurring on 37% of all 6‐hr time steps in all 10 years in the south at 13.5°N and 43°E, decreasing to 15% of the data farther north at 19.5°N and 39°E. The core of the jet was usually close to the ground, with occurrence maximized at the 925 and 950 hPa levels corresponding roughly to 540–800 m above sea level. The study defined three criteria for the jet based on peak wind speeds. The jets that met the weaker criterion were frequent north of the straight of Bab el Mandeb in the far southern part of the Red Sea. The jets that met the two stronger criteria were more frequent further north approximately between 14°–17°N and 39°–42°E. Although the jet was present in the strait of Bab el Mandeb as found in earlier studies, the extension of the jet so much farther north suggests that other processes besides channelling must be acting to produce this jet. It also appears that the jet plays a significant role in moisture advection towards the central Red Sea region, which can contribute towards precipitation there as it was found that the moisture concentration increased in that region when the LLJ was present. It must be noted, however, that the present study relied upon reanalysis data to document the jet. Upper level observations in the region are scarce, so caution should be used in the interpretation of the results.
Analyses of the oceanic heat content during 1980–2014 and satellite‐era cyclones over Bay of Bengal
Authors: T. S. Anandh , Das Bijan Kumar , Kumar Bishnu , Kuttippurath Jayanarayanan , Chakraborty Arun
Published: August 2018

Bay of Bengal (BoB) is one of the most cyclone prone regions in the world. Cyclones receive energy from warm ocean surface waters and the change in cyclone activity generally depends on the change in heat energy available in the upper ocean. Here, we use satellite‐based Modern Era Retrospective‐analysis for Research and Applications dataset, and reanalysis of Simple Ocean Data Assimilation (SODA) and European Centre for Medium‐range Weather Forecasts–Ocean ReAnalysis System 4 (ECMWF–ORAS4) to analyse the oceanic heat content (OHC) and heat flux to identify sources of the additional heat input in the region during the period 1980–2014. It has been observed that during 1999–2014, heat energy is mainly stored in the southern and northwestern parts of the bay and it shows an increasing trend in both regions. In the analysis of OHC, the European Centre for Medium‐range Weather Forecasts (ECMWF) data show a trend of −0.87 × 1018 J/month during 1980–1998 and 7.58 × 1018 J/month during 1999–2014 whereas, the SODA data show a trend of 0.94 × 1018 J/month during 1980–1998 and 5.25 × 1018 J/month during 1999–2014. It is found that many cyclones are seeded in the southeastern bay and intensified over the northwestern bay, consistent with the increase in cyclone heat potential and the upper ocean heat content (UOHC) in those regions. The heat flux in the bay is primarily governed by the heat entering the eastern side and leaving through the western side. In 1999–2014, the incoming heat flux along the eastern boundary has increased significantly (from 0.18 × 1012 to 0.57 × 1012 W/month), indicating that more heat enters the region. Furthermore, a significant reduction in the outgoing heat flux along the western boundary has also been found from the analysis. These processes trap the heat and thereby contributing to the increase in OHC in the bay. The heat flux through the bay is mainly linked with conditions prevailing over Pacific Ocean, such as, the heat influx of BoB decreases during El‐Nino and increases during La‐Nina years.
Decadal change in the relationship between East Asian spring circulation and ENSO: Is it modulated by Pacific Decadal Oscillation?
Authors: Wang Yuhao , He Chao , Li Tim
Published: August 2018

Using the NOAA‐CIRES 20th century Reanalysis and the ERA‐20C reanalysis, the decadal changes in the relationship between East Asian spring circulation (EASC) and ENSO over the past century are investigated. These two datasets consistently show that a decadal change occurred around 1972 for the late 20th century, which coincides with the shift of Pacific Decadal Oscillation (PDO) from the negative to the positive phase. While the interannual variability of EASC is closely related to El Niño‐Southern Oscillation (ENSO) during 1973–2000, it is weakly related to ENSO but seems to be dominated by midlatitude atmospheric variability during 1952–1972. However, the relationship between EASC and ENSO is inconsistent between the two reanalysis datasets in the first half of the 20th century, raising a question whether PDO does have a modulation on the ENSO–EASC relationship or it just occurred by chance in 1970s. The pre‐industrial control (PIC) experiment of the coupled models from CMIP5 are analysed to address this question. In the long‐term simulation of the coupled models under fixed external forcing, the relationship between ENSO and EASC does show substantial decadal oscillation, just as in the observation, but the strength of the ENSO–EASC relationship is not substantially in phase with PDO. Forced by observed sea surface temperature from 1950 to 2010, an atmospheric general circulation model corroborates that the EASC–ENSO relation is almost steady after removing the atmospheric internal variability regardless of the phase of PDO, but it is subject to strong decadal oscillation in the multiple ensemble members with the stochastic modulation of atmospheric internal dynamics. These modelling evidences support the null hypothesis that the relationship between EASC and ENSO is not modulated by PDO.
Mediterranean winter snowfall variability over the past millennium
Authors: Diodato Nazzareno , Büntgen Ulf , Bellocchi Gianni
Published: August 2018

The brevity of the instrumental record limits our understanding of snowfall variability and its directional patterns in the Mediterranean region. Here, we develop a 1,208‐year‐long (800–2017 CE) reconstruction of central Mediterranean snowfall variability based on documentary evidence from Italy. The record suggests that the recent reduction in Italian snowfall intensity is not unprecedented over the past millennium, since comparable patterns of low snowfall intensity also occurred during the Medieval Climate Anomaly. Increased snowfall during the Little Ice Age, however, was most likely associated with a shift of the Atlantic multi‐decadal variability towards negative values, and this overall cold phase further coincided with increased volcanic activity. Our findings on natural snowfall variability over the central Mediterranean in the past millennium provide a unique winter proxy for validating output from climate model simulations.
Molecular species determination of oligosaccharides and glycoconjugates in soybean lecithin powders
Authors: Kang Jingjing , Yin Ru , Cao Dong
Published: August 2018

BACKGROUND

Oligosaccharides and glycoconjugates in soybean lecithin powder are very important for the properties and functions of the materials that contain it. Oligosaccharides can trigger infusion reactions and color changes in soybean lecithin during medical injections; glycoconjugates in the form of glycolipids can also change the physical behavior of lecithin. The molecular components of oligosaccharides and glycoconjugates in soybean lecithin powder were studied in this paper.

RESULTS

Three oligosaccharides and 21 glycoconjugates were verified in soybean lecithin powders for the first time. Raffinose, sucrose, and stachyose were detected as the principal components of oligosaccharides by high‐performance liquid chromatography (HPLC). Twenty‐one glycoconjugates, including four steryl glucosides (SG), 13 acyl steryl glucosides (ASG), one digalactosyl diacylglycerol (DGDG), one monogalactosyl diacylglyceride (MGDG), one glucocerebroside (Glucer), and one glucose palmitate were analyzed by gas chromatography (GC), gas chromatography–mass spectrometry (GC‐MS) and RP‐UPLC‐Q‐TOF‐ESI‐MS. Glycoconjugates were constructed in soybean lecithin powder after separation by column chromatography, thin‐layer chromatography, and color reactions.

CONCLUSION

The determination of molecular species of oligosaccharides and glycoconjugates provided a new direction for the exploration of novel functions and uses of soybean lecithin powder. © 2018 Society of Chemical Industry
Synthesis and characterization of MIL‐101(Cr) intercalated by polyaniline composite, doped with silica nanoparticles and its evaluation as an efficient solid‐phase extraction sorbent
Authors: Ghiasvand Ali Reza , Ghaedrahmati Leila , Heidari Nahid , Haddad Paul R. , Farhadi Saeid
Published: August 2018

A metal–organic framework/polyaniline composite was synthesized and doped with silica nanoparticles. The structure and morphology of the composite were characterized using Fourier transform infrared spectroscopy and scanning electron microscopy. It was packed inside a cartridge and evaluated for the solid‐phase extraction of thymol and carvacrol, followed by gas chromatography with flame ionization detection measurement. The influence of the important experimental variables on the efficiency of the proposed method, including pH, ionic strength, volume of sample solution and type, and volume of eluent were studied and optimized. Under the optimal conditions, the relative standard deviations were found to be 3.8 and 9.8% for thymol and carvacrol, respectively, and the corresponding limits of detection were 0.1 and 1.0 ng/mL. The linear dynamic ranges for the calibration curves of the analytes were 10–10000 ng/mL, with determination coefficients (R2) > 0.993. The limits of quantifications were found to be 0.01 and 0.5 μg/mL, for thymol and carvacrol, respectively. The prepared nanocomposite sorbent was applied successfully to the extraction and determination of thymol and carvacrol in Lamiaceae plant extracts and a honey sample, with relative recoveries in the range of 90.28–122.0%.
Synthesis and evaluation of a pentafluorobenzamide stationary phase for HPLC separations in the reversed phase and hydrophilic interaction modes
Authors: Ferreira Claudio de Castro , Gama Mariana Roberto , da Silva Gisele Silvestre , Almeida Wanda Pereira , Collins Carol Hollingworth , Jardim Isabel Cristina Sales Fontes
Published: August 2018

A pentafluorobenzamide stationary phase was synthesized by an easy method with no intermediate purification steps. Physicochemical characterization (elemental analysis, fourier transform infrared spectroscopy, 29Si and 13C nuclear magnetic resonance spectroscopy) confirmed the presence of pentafluorobenzamide functionalization on the surface of the silica particles. The pentafluorobenzamide stationary phase proved to be quite versatile as it can be used in two different modes in liquid chromatography: reversed phase and hydrophilic interaction liquid chromatography. Chromatographic characterizations in both modes confirmed the multiple interactions established by the new stationary phase, such as hydrogen bonding and π‐π and ion‐exchange interactions. The pentafluorobenzamide stationary phase was successfully employed for the separation of nucleosides and antihypertensive drugs under hydrophilic interaction liquid chromatography conditions, as well as pesticides and benzodiazepine using reversed phase conditions. The stationary phase showed significant potential when compared with commercial columns.
Examining incentive travelers: How motivation affects organizational commitment
Authors: Li Xiaoli , Lu Lu , Chi Christina Geng‐Qing
Published: August 2018

This study examines incentive travelers' motivation and the relationships between motivation, satisfaction, and organizational commitment. A mixed‐methods approach was employed to customize the measures and provide empirical evidence on proposed interrelationships. Factor analysis has revealed three types of travel motivation, including “travel for business networking,” “travel for leisure,” and “travel for prestige.” Partial least squares structural equation modeling results suggest that the three motivations are positively related to satisfaction with incentive travel. Travel for business networking and travel for prestige exhibit positive effects, whereas travel for leisure has a negative effect on organizational commitment. All the three motivations are positively related to organizational commitment through satisfaction.
Corrosion resistance of WC–Co and WC–Ni type sintered carbides in acetic acid water solution
Authors: Richter Janusz , Michalik Rafał
Published: August 2018

Corrosion resistance of sintered WC carbides products is an important factor determining their service properties. As an alternative to cobalt binders mainly nickel based matrices are introduced to increase corrosion resistance. To assess the effect of the metallic binder and carbide grain size on electrochemical corrosion susceptibility two grades with conventional cobalt matrices and two sinters with nickel were investigated. The gravimetric (weight) as well as electrochemical (potentiodynamic, potentiostatic, and galvanostatic) measurements in a 10% water solution of acetic acid were performed. The cobalt samples were characterized by lower corrosion resistance in comparison with the nickel containing grades. In most cases the investigated samples revealed a tendency to self‐passivation, the phenomena being more intense in the nickel sinters. Both electrochemical and gravimetric measurements showed that the increased fraction of the metallic phase and microstructural inhomogeneity lowered the corrosion resistance. The variation in grain size in <1 μm ÷ 3 μm interval did not significantly affect the corrosion intensity.
Characterization of localized corrosion of heat treated Er‐ and Zr‐containing A356 alloys in 3.5 wt% NaCl aqueous solution
Authors: Colombo Marco , Buzolin Ricardo H. , Gariboldi Elisabetta , Vallant Rudolf , Sommitsch Christof
Published: August 2018

The influences of Er and Zr additions on the corrosion behavior of A356 (Al‐7Si‐0.4Mg) alloy are investigated. Electrochemical tests (potentiodynamic polarization and electrochemical impedance spectroscopy), gravimetric analyses, and microstructural investigations demonstrate that 0.3 wt% Er nominal addition is beneficial for the corrosion resistance of A356 alloy, due to a modified eutectic morphology and a low volume fraction of intermetallic compounds. The further addition of about 0.5 wt% Zr, on the other hand, partially reduces the corrosion resistance of Er‐containing A356 alloy, possibly due to a higher amount of intermetallic compounds which promote corrosion localization.
A method of atmospheric corrosion prediction for aircraft structure
Authors: Chen Yueliang , Huang Hailiang , Zhang Yong , Wang Chenguang , Fan Weijie
Published: August 2018

A simulation prediction system, test pieces → flat test pieces → structural parts, for the atmospheric corrosion of aircraft is proposed to provide guidance for aircraft anti‐corrosion material selection and outfield maintenance. Based on the shell current distribution, a COMSOL corrosion simulation prediction model was constructed and applied to three types of test parts. The correctness of simulation principle is verified by comparing the galvanic current of simulation and test on each electrode surface of multi‐electrode system. Comparing the simulated potential distribution at 100 µm electrolyte layer with the corrosion morphology after 12 wet–dry corrosion periods, it is found that simulation and test are in good agreement. It is also proved that the 100 µm static liquid film can reflect the corrosion of this kind of wet–dry cycle. Comparing the corrosion depths of different periods at three different points and the simulated corrosion depth with time, it is found that the corrosion depth of the first four periods was larger than the simulated depth, which was less than the simulated value after four periods. The model was applied to the local structural parts of aircraft. Then, corrosion position and corrosion area were predicted. The results were compared with the accelerated test results to verify the accuracy of the model's prediction of structural parts. At the same time, the corrosion depth of the structural parts was also predicted.
Inflection of backward sweep of cyclic polarization curve: Pit transition potential Eptp
Authors: Sun Qingqing , Chen Kanghua
Published: August 2018

The influences of ex‐situ applied load, scan circle, reverse potential, chloride concentration, and temperature on inflection (Eptp) of backward sweep of cyclic polarization of 7150 Al alloy were investigated. The 2nd derivative of polarization curves was used to accurately determine the value of Eptp. Eptp is determined as the potential where massive metastable pits finished their repassivation process during reverse scan, providing an insight into highly constricted forms of localized corrosion repassivation. Chloride ion and diffusion condition have predominant effects on this inflection. Eptp showed non‐monotonic trend with temperature and relevant discussion was given as well.
Zwitterionic Copolymerization of β‐Butyrolactone with Styrene
Authors: Xiao Meina , Jiang Jingxing , Zhang Tongtong , Xu Anli , Ke Zhuofeng , Hong Liangzhi
Published: August 2018

The hybrid copolymerization of vinyl monomers with cyclic esters endows the formed copolymers new features, such as biodegradability and functionality. However, the recently reported hybrid copolymerizations are mainly based on polar vinyl monomers and cyclic esters catalyzed by organocatalysts. The copolymerization of non‐polar vinyl monomers with cyclic esters is still a challenge. In this work, the copolymerization of β‐butyrolactone (β‐BL) with styrene catalyzed by B(C6F5)3 in the absence of coinitiators is reported. The density functional theory studies suggest the formation of zwitterion between β‐BL and B(C6F5)3. It is found that β‐BL and styrene are concurrently copolymerized through the macro‐zwitterion intermediates. The obtained copolymers are carefully examined by 1H NMR, 2D 1H‐13C HMBC, differential scanning calorimetry, thermogravimetric analysis, hydrolysis experiments, as well as Brady's reagents.
Electrochemically Generated Conjugated Microporous Polymer Network Thin Films for Chemical Sensor Applications
Authors: Suresh Venkata M. , Scherf Ullrich
Published: August 2018

Electrogenerated π‐conjugated microporous polymer network (CMPN) thin films are potential materials for highly sensitive detection of harmful chemical species as they show fast response, high signal amplification, and easy fabrication of devices. In the last few years, several CMPN thin films from carbazolyl and thienyl monomer building blocks having a variety of aromatic cores have been reported for different applications including organic electronics, electrochemical supercapacitors, chemical sensors. This article reviews the approaches toward the preparation of electrogenerated CMPN thin films and their application in electrochemical and fluorescence quenching–based sensing of nitroaromatics, metal ions, etc.
Controlled ROMP Synthesis of Ferrocene‐Containing Amphiphilic Dendronized Diblock Copolymers as Redox‐Controlled Polymer Carriers
Authors: Liu Xiong , Qiu Guirong , Zhang Li , Liu Fangfei , Mu Shengdong , Long Yanru , Zhao Qiuxia , Liu Yue , Gu Haibin
Published: August 2018

Novel well‐defined redox‐responsive Ferrocene (Fc)‐containing amphiphilic dendronized diblock copolymers are synthesized by the ring‐opening metathesis polymerization technique using Grubbs’ third‐generation olefin metathesis catalyst as the initiator. These dendronized block copolymers can self‐assemble into spherical micelles in aqueous solution. The size of self‐assembled micelles can be modulated by the composition (namely, the ratio of hydrophobic and hydrophilic segments) and concentration of the dendronized copolymers. The obtained micelles show reversible redox‐controlled self‐assembly behaviors using FeCl3 as oxidant and glutathione as reductant. Furthermore, the model molecule Rhodamine B is successfully loaded in these micelles, and the oxidation‐triggered controllable release is achieved by changing the type of oxidants (FeCl3 and H2O2) and their concentrations. This is the first example of redox‐responsive micelles self‐assembled by novel amphiphilic dendronized Fc‐containing block copolymers, and the present micelles are visualized to be potential candidates in many fields, especially in stimuli‐responsive drug delivery systems.
A Variable Stiffness Spring–Sponge Composite Tube with Fast Response and Shape Recovery
Authors: Ren Xuyang , Zhang Guokai , Shang Zufeng , Wang Shuxin
Published: August 2018

Soft robots have attracted more and more attention from researchers in the past decades, and multiple materials and methods have been studied to solve the conflict between strength and adaptability. This paper presents a novel composite tube comprising a spring and sponge, which can transform between stiffness and softness, and also proposes a corresponding novel method to alter the stiffness of the tube swiftly and reliably. Additionally, studies indicate that the tube exhibits shape‐recovery ability. The potential applications of the tube are illustrated in a coat of the supporting structure in the natural orifice transluminal endoscopic surgery instrument, a fixing device for human arthrosis and skeleton rehabilitation, and a variable stiffness multidirectional actuator.
Direct Femtosecond Laser Printing of PPV on Bacterial Cellulose‐Based Paper for Flexible Organic Devices
Authors: Avila Oriana I. , Santos Moliria V. , Shimizu Flavio M. , Almeida Gustavo F. B. , Siqueir Jonathas P. , Andrade Marcelo B. , Balogh Debora T. , Ribeiro Sidney J. L. , Mendonca Cleber R.
Published: August 2018

Cellulose‐based flexible electronics has prompted as an interesting approach for the development of novel technologies, given its unique properties. Standard printing methods, however, limit the materials to be transferred, as well as the resolution of the patterns. In this paper the use of femtosecond laser induced forward transfer is demonstrated, for creating high‐resolution patterns of the conductive poly(p‐phenylene vinylene) (PPV), an advanced material that presents outstanding electrical properties, on bacterial cellulose (BC) substrate. Such an approach successfully allows transferring PPV with a resolution on the order of 10 µm and without the material's degradation, which is subsequently doped to increase the electrical conductivity. Therefore, results presented herein open new avenues in the fabrication of paper‐based devices, by combining high resolution and new classes of patterning materials.
Processing‐Driven Morphology Development and Crystallization Behavior of Immiscible Polylactide/Poly(Vinylidene Fluoride) Blends
Authors: Salehiyan Reza , Ray Suprakas Sinha , Ojijo Vincent
Published: August 2018

Processing‐driven morphology development and crystallization behavior of immiscible polymer blends are of high significance for the development of polymeric materials with controllable properties. This study correlates processing‐induced morphology alterations of different polylactide/poly(vinylidene fluoride) (PLA/PVDF) blends with their crystallization behavior, showing that blending can benefit the crystallization of both phases. X‐ray diffraction analysis reveals the facile formation of β‐PVDF crystals upon 10‐min blending of a 30/70 (w/w) PLA/PVDF ratio, which is ascribed to the more uniform distribution of smaller PLA droplets in the PVDF matrix observed for this composition and processing time. On the other hand, dispersion of smaller PVDF droplets inside the PLA matrix increases the crystallinity of the latter, while the crystallinity of PVDF droplets is increased by their coalescence. The results of differential scanning calorimetry (DSC) analysis confirm that PVDF promotes the crystallization of PLA by improving its crystallization enthalpy in blends, whereas no such effect is observed for crystallization of neat PLA from the melt. Finally, nonisothermal DSC analysis of a 50/50 PLA/PVDF blend at different cooling rates reveals that slow crystallization results in enhanced blend crystallinity.
Expected intrinsic volumes and facet numbers of random beta‐polytopes
Authors: Kabluchko Zakhar , Temesvari Daniel , Thäle Christoph
Published: August 2018

Let be i.i.d. random points in the d‐dimensional Euclidean space sampled according to one of the following probability densities:
urn:x-wiley:0025584X:media:mana201700255:mana201700255-math-0002and
urn:x-wiley:0025584X:media:mana201700255:mana201700255-math-0003We compute exactly the expected intrinsic volumes and the expected number of facets of the convex hull of . Asymptotic formulae were obtained previously by Affentranger [The convex hull of random points with spherically symmetric distributions, 1991]. By studying the limits of the beta case when , respectively , we can also cover the models in which are uniformly distributed on the unit sphere or normally distributed, respectively. We obtain similar results for the random polytopes defined as the convex hulls of and . One of the main tools used in the proofs is the Blaschke–Petkantschin formula.
Identification of paternal uniparental disomy on chromosome 22 and a de novo deletion on chromosome 18 in individuals with orofacial clefts
Authors: Oseni Ganiyu O. , Jain Deepti , Mossey Peter A. , Busch Tamara D. , Gowans Lord J.J. , Eshete Mekonen A. , Adeyemo Wasiu L. , Laurie Cecelia A. , Laurie Cathy C. , Owais Arwa , Olaitan Peter B. , Aregbesola Babatunde S. , Oginni Fadekemi O. , Bello Saidu A. , Donkor Peter , Audu Rosemary , Onwuamah Chika , Obiri‐Yeboah Solomon , Plange‐Rhule Gyikua , Ogunlewe Olugbenga M. , James Olutayo , Halilu Taiye , Abate Firke , Abdur‐Rahman Lukman O. , Oladugba Abimbola V. , Marazita Mary L. , Murray Jeffrey C. , Adeyemo Adebowale A. , Butali Azeez
Published: August 2018

Background

Orofacial clefts are the most common malformations of the head and neck region. Genetic and environmental factors have been implicated in the etiology of these traits.

Methods

We recently conducted genotyping of individuals from the African population using the multiethnic genotyping array (MEGA) to identify common genetic variation associated with nonsyndromic orofacial clefts. The data cleaning of this dataset allowed for screening of annotated sex versus genetic sex, confirmation of identify by descent and identification of large chromosomal anomalies.

Results

We identified the first reported orofacial cleft case associated with paternal uniparental disomy (patUPD) on chromosome 22. We also identified a de novo deletion on chromosome 18. In addition to chromosomal anomalies, we identified cases with molecular karyotypes suggesting Klinefelter syndrome, Turner syndrome and Triple X syndrome.

Conclusion

Observations from our study support the need for genetic testing when clinically indicated in order to exclude chromosomal anomalies associated with clefting. The identification of these chromosomal anomalies and sex aneuploidies is important in genetic counseling for families that are at risk. Clinicians should share any identified genetic findings and place them in context for the families during routine clinical visits and evaluations.
Microdosimetric considerations for radiation response studies using Raman spectroscopy
Authors: Oliver Patricia A. K. , Thomson Rowan M.
Published: August 2018

Purpose

Recent Raman spectroscopy (RS) studies of radiation response involve subcellular (μm‐scale) sampling volumes and macroscopic doses as low as 0.005 Gy. These studies ignore the stochastic nature of radiation transport and energy deposition, which can lead to considerable microdosimetric “spread” (i.e., variation in energy deposition). The goal of this work is to use Monte Carlo (MC) simulations to investigate the microdosimetric spread across populations of microscopic targets relevant for RS studies of cellular radiation response.

Methods

Simulation geometries involve populations of 1600 cells, with two sizes of sampling volumes (representative of recent RS studies) considered within each nucleus, as well as averaging over multiple sampling volumes in the same nucleus. To investigate variation in microdosimetric spread as a function of dose and target size, simple cubic voxel geometries are also considered. MC simulations are used to score energy imparted per unit mass (specific energy, z) in targets (nuclei, sampling volumes, and voxels), considering doses from a few mGy to several Gy. Three photon spectra are considered: 120 kVp x‐ray, cobalt‐60, and a 6 MV medical linac.

Results

For μm‐sized targets, there can be considerable variation in energy deposition across a population of targets: the specific energy distribution is skewed, a large fraction of targets receive no energy, and the standard deviation of the specific energy relative to the mean, , is considerable. These results vary with source energy and (macroscopic) dose: for 60Co with cylindrical nuclei of 12.8 μm height and diameter, is 17% at 0.02 Gy, decreasing to 2% at 2 Gy. In contrast, for cylindrical sampling volumes with 1 μm diameter and 4 μm height, is 170% at 0.02 Gy and 18% at 2 Gy. Results of MC simulations involving cubic voxel geometries are fit to an equation relating the relative standard deviation of the specific energy to the target volume and dose; additionally, specific energy distributions are compared with normal distributions.

Conclusions

Microdosimetric considerations are important for RS cellular radiation response studies, especially for low doses. The results of this work may motivate changes to current measurement and data analysis methods for RS experiments, and motivate future work comparing MC simulation results with RS measurements to advance understanding of radiation response.
The effect of the flattening filter on photoneutron production at 10 MV in the Varian TrueBeam linear accelerator
Authors: Montgomery Logan , Evans Michael , Liang Liheng , Maglieri Robert , Kildea John
Published: August 2018

Purpose

Neutrons are an unavoidable by‐product of high‐energy radiation therapy treatments that deliver unwanted nontarget dose to patients. Use of flattening‐filter‐free (FFF) photon beams has been shown to significantly reduce photoneutron production per monitor unit (MU) of dose delivered. The purpose of this investigation was to characterize the photoneutron production of the 10 MV and 10 MV FFF beams of the Varian TrueBeamTM linear accelerator.

Methods

Neutron fluence spectra were measured using a Nested Neutron SpectrometerTM (NNS, Detec Inc., Gatineau, Canada). The ratios of neutron fluence and ambient dose equivalent for the 10 MV FFF beam relative to the 10 MV beam, dubbed FF‐ratios (FFF/FF), were used to characterize the difference between the two beams. FF‐ratios were compared under the following three conditions (a) per MU, at various locations in the treatment room, (b) per MU, with the linac jaws opened and closed, and (c) per electron striking the bremsstrahlung target, as opposed to per MU, at one location with the jaws closed.

Results

On average, the neutron fluence for the 10 MV FFF beam was 37% lower per MU than the 10 MV beam (FF‐ratio = 0.63). The FF‐ratio in neutron fluence and ambient dose equivalent did not vary by much between different locations within the treatment room. However, the FF‐ratio in neutron ambient dose equivalent was reduced significantly when the linac jaws were opened compared to closed, which implies that the jaws contribute more to the photoneutron spectrum of the 10 MV FFF beam than to the 10 MV beam. Finally, it was found that the 10 MV FFF beam produces more photoneutrons per electron striking the bremsstrahlung target than the 10 MV beam (FF‐ratio = 2.56).

Conclusions

The photoneutron fluence per MU produced by the 10 MV FFF beam is 37% lower than the 10 MV beam of a Varian TrueBeam linac. Accordingly, a reduction in neutron dose received by patients is achieved through use of the unflattened beam, provided that treatment plans for each beam require approximately the same number of MU. It was found to be instructive to compare the photoneutron yield per source electron between the two beams as it helped provide an understanding of the physics underlying photoneutron production in both beams.
An NMR crystallography investigation of furosemide
Authors: Zilka Miri , Yates Jonathan R. , Brown Steven P.
Published: August 2018

This paper presents an NMR crystallography study of three polymorphs of furosemide. Experimental magic‐angle spinning (MAS) solid‐state NMR spectra are reported for form I of furosemide, and these are assigned using density‐functional theory (DFT)‐based gauge‐including projector augmented wave (GIPAW) calculations. Focusing on the three known polymorphs, we examine the changes to the NMR parameters due to crystal packing effects. We use a recently developed formalism to visualise which regions are responsible for the chemical shielding of particular sites and hence understand the variation in NMR parameters between the three polymorphs.
Humanitarian response to hurricane disasters: Coordinating flood‐risk mitigation with fundraising and relief operations
Authors: Chakravarty Amiya K.
Published: August 2018

To alleviate flooding, caused by hurricanes, governments build structural barriers called levees. In addition, relief providers such as the nongovernmental organizations and charities raise funds, and procure and deliver supplies (food, water, and medicines) for humanitarian relief. The strategy for managing disasters must, therefore, weigh the costs and benefits of building levees as well as procuring and delivering supplies. We use a three‐stage decision making framework to study how the investment in levee capacity can be integrated with supply procurements, fundraising, and rapid response. One of our major findings is that a large fundraising cost discourages postdisaster funding, implying relatively large investments in levee and prepositioned supplies. That notwithstanding, a large social value (of saving life) can tilt the balance in favor of postdisaster funding. If the levee capacity increases, funding for predisaster procurement is reduced without affecting postdisaster funding. For a sufficiently large increase in capacity, however, postdisaster response becomes superfluous. We also find that hurricane uncertainty motivates levees with large capacity. In contrast, levee‐failures motivate levees with small capacity.
Differentiation of the phenolic chemical profiles ofCecropia pachystachyaandCecropia hololeuca
Authors: da Silva Mathias Marcelo , Rodrigues de Oliveira Rodrigo
Published: August 2018

Introduction

Cecropia pachystachyaandC. hololeucaare common species in Brazil, popularly used to treat respiratory diseases. Phytochemical studies indicate that their leaves are rich in phenolic compounds, mainlyC‐glycosilated flavonoids. Orientin and isoorientin are reported in both species, while vitexina and isovitexina were reported inC. pachystachya. In addition, both are rich in chlorogenic acid and have some procyanidins. In some cases, syrups and teas are prepared from leaf blends from different species, which may affect the efficacy and safety of this natural medication. This problem motivated the investigation of the chemical profile of leaves of these species.

Objective

The phenolic chemical profiles fromC. pachystachyaandC. hololeucamethanolic extracts were analysed by ultra‐high performance liquid chromatography coupled with a diode array detector and mass spectrometry (UPLC‐DAD‐MS), to investigate possible differences in their metabolite production.

Material and Methods

The methanolic extracts of both species were analysed by UPLC‐DAD‐MS using a C‐18 reverse phase column, DAD at 190–400 nm and electrospray ionisation quadruple time‐of‐flight (ESI‐Q‐TOF) mass spectrometer. The separation methodology was validated and most of the flavones present in the extracts were quantified.

Results

Thirty‐seven compounds were tentatively identified, including flavonoids, phenolic acids, flavan‐3‐ols, condensed tannins (procyanidins) and iridoids, through UV analysis and tandem mass spectrometry (MS/MS) spectra obtained in the negative mode. Chlorogenic acid, orientin and isoorientin were observed as the major constituents in both extracts.

Conclusions

Cecropia pachystachyapresented a more diverse chemical profile thanC. hololeuca. The methodology developed herein could be an important tool to analyse commercialCecropia(embaúba) products.
The several facets of Trichogin GA IV: High affinity Tb(III) binding properties. A spectroscopic and molecular dynamics simulation study
Authors: Gatto Emanuela , Palleschi Maria Elena , Zangrilli Beatrice , De Zotti Marta , Di Napoli Benedetta , Palleschi Antonio , Mazzuca Claudia , Formaggio Fernando , Toniolo Claudio , Venanzi Mariano
Published: August 2018

Trichogin GA IV (TrGA) is an antimicrobial peptide isolated from Trichoderma longibrachiatum. The amino acid sequence of TrGA is rather peculiar, because it is characterized by three Aib and four Gly residues, which confer unique dynamic and structural properties. In a previous study, we found that TrGA shows excellent binding properties to Ca(II) and lanthanide Gd(III) ions in acetonitrile solutions. Within the lanthanide ions, Tb(III) ions possess fascinating optical characteristics, such as luminescence which greatly improves after coordination. Here, we present the results of our spectroscopic and molecular dynamics investigations on the Tb(III) ion‐binding properties of an Nα‐Fmoc functionalized analog of Trichogin GA IV (F0TrOMe). The high Tb(III) ion‐F0TrOMe affinity, together with the proteolytic resistance and membrane affinity of the natural compound, confers to this system potentially promising applications in several fields, such as bioimaging and bioanalytical assays.