bluuebunny/crossref_metadata_2025 huggingface dataset:
Relative size variation of the otoliths, swim bladder, and Weberian apparatus structures in piranhas and pacus (Characiformes: Serrasalmidae) with different ecologies and its implications for the detection of sound stimuli
Authors: Boyle Kelly S. , Herrel Anthony
Published: November 2018

The Weberian apparatus of otophysan fishes confers acute hearing that is hypothesized to allow these fishes to assess the environment and to find food resources. The otophysan family Serrasalmidae (piranhas and pacus) includes species known to feed on falling fruits and seeds (frugivore/granivores) that splash in rivers, herbivorous species associated with torrents and rapids (rheophiles), and carnivores that feed aggressively within shoals. Relevant sound stimuli may vary among these ecological groups and hearing may be tuned to different cues among species. In this context, we examined size variation of the Weberian ossicles, swim bladder chambers, and otoliths of 20 serrasalmid species from three broad feeding ecologies: frugivore/granivores, rheophiles, and carnivores. We performed 3D‐reconstructions of high resolution tomographic data (μCT) from 54 museum specimens to estimate the size of these elements. We then tested for an ecology effect on covariation of auditory structure size and body size and accounted for phylogeny with phylogenetic generalized least squares analyses. Among ecological groups, we observed differences in relative sizes of otoliths associated with sound pressure and particle motion detection, and variation in Weberian ossicle size that may impact sound transmission. Rheophiles, which live in noisy environments, possess the strongest modifications of these structures.
Accelerated multi‐snapshot free‐breathing mapping based on the dual refocusing echo acquisition mode technique (DREAM): An alternative to measure RF nonuniformity for cardiac MRI
Authors: Rincón‐Domínguez Teresa , Menini Anne , Solana Ana Beatriz , Fischer André , Kudielka Guido , Haase Axel , Burschka Darius
Published: November 2018

Background

Field inhomogeneities in MRI caused by interactions between the radiofrequency field and the patient anatomy can lead to artifacts and contrast variations, consequently degrading the overall image quality and thereby compromising diagnostic value of the images.

Purpose

To develop an efficient free‐breathing and motion‐robust mapping method that allows for the investigation of spatial homogeneity of the transmitted radiofrequency field in the myocardium at 3.0T. Three joint approaches are used to adapt the dual refocusing echo acquisition mode (DREAM) sequence for cardiac applications: (1) electrocardiograph triggering; (2) a multi‐snapshot undersampling scheme, which relies on the Golden Ratio, to accelerate the acquisition; and (3) motion‐compensation based on low‐resolution images acquired in each snapshot.

Study type

Prospective.

Phantom/subjects

Eurospin II T05 system, torso phantom, and five healthy volunteers.

Field strength/sequence

3.0T/DREAM.

Assessment

The proposed method was compared with the Bloch‐Siegert shift (BSS) method and validated against the standard DREAM sequence. Cardiac maps were obtained in free‐breathing and breath‐hold as a proof of concept of the in vivo performance of the proposed method.

Statistical tests

Mean and standard deviation (SD) values were analyzed for six standard regions of interest within the myocardium. Repeatability was assessed in terms of SD and coefficient of variation.

Results

Phantom results indicated low deviation from the BSS method (mean difference = 3%). Equivalent distributions for free‐breathing and breath‐hold in vivo experiments demonstrated the motion robustness of this method with good repeatability (SD < 0.05). The amount of variations was found to be 26% over the myocardium within a short axis slice.

Data conclusion

The feasibility of a cardiac mapping method with high spatial resolution in a reduced scan time per trigger was demonstrated. The free‐breathing characteristic could be beneficial to determine shim components for multi‐channel systems, currently limited to two for a single breath‐hold.

Level of Evidence: 1

Technical Efficacy: Stage 1

J. Magn. Reson. Imaging 2019;49:499–507.
White matter myelin profiles linked to clinical subtypes of Parkinson's disease
Authors: Baumeister Tobias R. , Kim Jowon L. , Zhu Maria , McKeown Martin J.
Published: November 2018

Background

White matter (WM) microstructural integrity is important for effective brain functioning and alterations have been shown in many neurodegenerative diseases.

Purpose

To investigate WM myelin profiles and their relation to clinical features of Parkinson's disease (PD).

Study Type

Retrospective cross‐sectional.

Population

In all, 29 PD subjects and 15 healthy controls.

Field Strength/Sequence

Multiecho GRASE with 10 msec echo spacing and echo planar imaging (EPI) diffusion‐weighted (b‐value = 700 with 32 gradient directions) on a 3T scanner.

Assessment

Myelin water fraction (MWF) and fractional anisotropy (FA) across 20 WM regions of interest (ROIs) were compared between groups. Partial least squares (PLS) was used to associate MWF and FA with clinical and behavioral measures.

Statistical Tests

Group comparisons were done using two‐sample t‐tests. PLS was assessed with permutation tests. Bootstrapping was used to investigate the robustness of imaging features.

Results

No group differences in myelin content could be detected with univariate tests. A three‐component PLS model linked MWF profiles to clinical phenotypes but no FA profiles. The three components appeared to follow along broad motor/nonmotor subtypes of “akinetic‐rigid,” “tremor‐predominant,” and “depression/apathy” subtypes, respectively. The first component showed associations between overall motor scores (r = –0.43, P = 0.0196) and cognitive performance (r = 0.44, P = 0.0171) with interhemispheric and long‐range association fibers. A second component linked overall motor scores (r = –0.58, P = 0.0009) and tremor scores (r = –0.48, P = 0.0091) to predominantly projection fibers. The last component related depression (r = –0.60, P = 0.0006) and apathy scores (r = –0.66, P = 0.0001 and r = –49, P = 0.0072) to a mixture of association and projection fibers.

Data Conclusion

MWF was robustly linked to distinct clinical subtypes of PD and may serve as an additional tool to characterize the disease.

Level of Evidence: 4

Technical Efficacy: Stage 3

J. Magn. Reson. Imaging 2019;50:164–174.
Simultaneous screening and isolation of activated constituents from Puerariae Flos by ultrafiltration with liquid chromatography and mass spectrometry combined with high‐speed counter‐current chromatography
Authors: Wu Tong , Liu Chunming , Huang Yu , Li Sainan , Wang Yueqi
Published: November 2018

Puerariae Flos is the flower of Puerariae Radix, which is a common Chinese herb containing numerous isoflavones in all parts of the flower. Standard methods for screening and isolating isoflavones are typically labor intensive and time consuming. In this study, a new assay based on ultrafiltration with liquid chromatography and mass spectrometry was developed for the rapid screening and identification of ligands for α‐glucosidase, xanthine oxidase and lactate dehydrogenase in the extract of Puerariae Flos. Three isoflavones were identified as α‐glucosidase inhibitors, three isoflavones were identified as lactate dehydrogenase inhibitors, and no specific binding ligands were identified for xanthine oxidase in the extract. Subsequently, specific binding ligands, puerarin, genistin, and tectorigenin (purities were 90, 60, 99, and 91.73%, respectively), were separated by high‐speed counter‐current chromatography. The partition coefficient values of the target compounds and resolutions of peaks were employed as indicators and the solvent system and mobile phase flow rate were optimized for two‐stage separation. An optimized two‐phase solvent system comprised of ethyl acetate/ethanol/water (4:0.5:3, v/v/v) was successfully used to isolate the three compounds from Puerariae Flos. The monomer compounds isolated, collected, and purified by high‐speed counter‐current chromatography were analyzed by high‐performance liquid chromatography, resulting in the isolation of three targeted compounds. The chemical structures of all three targeted compounds were individually identified by ultra high performance liquid chromatography with high‐resolution mass spectrometry. The results demonstrate that ultrafiltration with liquid chromatography and mass spectrometry combined with high‐speed counter‐current chromatography is not only a powerful tool for screening and isolating α‐glucosidase and lactate dehydrogenase inhibitors in complex samples, but also a useful platform for identifying bioactive compounds for preventing and treating diabetes and stroke.
The Role of Real‐Time Elastography in the Differential Diagnosis of Salivary Gland Tumors
Authors: Karaman Can Zafer , Başak Sema , Polat Yasemin Durum , Ünsal Alparslan , Taşkın Füsun , Kaya Ebru , Günel Ceren
Published: November 2018

Objectives

The aim of the study was to scrutinize the value of qualitative elastography in the diagnosis of salivary gland masses.

Methods

Sixty patients were enrolled in this prospective study. Patients aged between 1 and 91 years (mean age, 48.8 ± 20.48) with a salivary gland mass were studied with real‐time elastography. All patients were examined by 1 examiner, blinded to all relevant data. On elastography, masses were scored into 4 types according to their stiffness compared to normal tissue. Scores of 3 and 4 were accepted as signs of malignancy. Sensitivity, specificity, and positive and negative predictive value were calculated for elastography in verifying malignancy.

Results

Forty‐two percent of the masses were located in the parotid, and the rest in submandibular gland. The diameter of the lesions varied between 12 and 60 mm (mean, 24.36 ± 11.98 mm). Forty‐four masses were benign (73%), and among them the majority were inflammatory lesions (31 of 60; 51.7%). There were 16 malignant lesions (27%). On elastography, not only all malignant lesions but 15 benign lesions were scored as 3 to 4. All masses scored as 1 to 2 were benign. Sensitivity was 100%; specificity, 66%; positive predictive value, 52%; and negative predictive value, 100%. When only Score 4 lesions were accepted as malignant, these values became 75%, 77%, 55%, and 90%, respectively.

Conclusions

Elastography alone cannot be used to discriminate malignant from benign in the evaluation of salivary gland lesions. However, with its high negative predictive value, it may be used as an adjunct tool to increase the diagnostic value of ultrasonography.
Defining differences in patient characteristics between spasmodic dysphonia and laryngeal tremor
Authors: Patel Priyesh N. , Kabagambe Edmond K. , Starkweather Jennifer C. , Keller Matthew , Ahmed Zaki A. , Gruber Simone C , Akins Jordan S , Garrett C. Gaelyn , Francis David O.
Published: November 2018

Objective

To compare presenting characteristics of patients with adductor spasmodic dysphonia (ADSD), ADSD with laryngeal tremor (ADSD + LT), and laryngeal tremor without ADSD (LT).

Design

Cross‐sectional analysis.

Methods

Patients treated for laryngeal movement disorders (1990–2016) were included. Analysis of variance and chi square tests measured differences in patient characteristics across the three disease groups. Using ADSD as the referent, multivariable logistic regression models were used to determine whether potential risk factors including patient demographics, family history, presence of potential inciting events prior to disease onset, and coprevalent movement disorders were associated with ADSD + LT or LT.

Results

In all, 652 patients with ADSD (n = 377), ADSD + LT (n = 98), and LT (n = 177) were included. ADSD patients were significantly younger than those with ADSD + LT and LT (52.5 ± 13.4, 63.9 ± 11.3, and 69.3 ± 10.5 years, respectively; P < 0.001). Coprevalent movement disorders were more common in ADSD + LT (38.7%) and LT (57.1%) groups than in the ADSD group (11.5%; P < 0.001). Compared to ADSD, patients with ADSD + LT and LT were more likely to develop an additional movement disorder during follow‐up. In multivariable analyses, increasing age, female gender, and having a movement disorder at presentation were associated with significantly greater odds of having ADSD + LT or LT when compared to ADSD.

Conclusion

ADSD + LT patients demonstrate intermediate gender composition and age distributions between those with ADSD and LT. These findings suggest that ADSD + LT may be a distinct phenotype in the spectrum of laryngeal movement disorders.

Level of Evidence

4 Laryngoscope, 129:170–176, 2019
Impact of a Formal Patient Safety and Quality Improvement Curriculum: A Prospective, Controlled Trial
Authors: Jamal Nausheen , Bowe Sarah N. , Brenner Michael J. , Balakrishnan Karthik , Bent John P.
Published: November 2018

Objective

To assess the impact of implementing a dedicated Patient Safety and Quality Improvement (PSQI) curriculum for otolaryngology residents.

Methods

Residents in two otolaryngology residency programs were recruited to participate in the study. Residents at institution A (intervention group) participated in a formal, newly developed, year‐long PSQI curriculum. Residents at institution B (control group) participated in traditional, morbidity, and mortality conference‐based PSQI education, with no formal curriculum in place. Curriculum participants completed anonymous surveys to assess learner satisfaction. Validated instruments were administered to assess for changes in resident confidence in the ability to develop PSQI projects, their attitudes toward patient safety, and PSQI‐related knowledge. The number and quality of PSQI‐related resident projects were also assessed.

Results

Survey responses demonstrated excellent learner satisfaction with the curriculum. Based on validated instrument‐based responses, both programs demonstrated similar confidence scores (P = 0.05), safety attitudes (P = 0.82), and PSQI knowledge (P = 0.29) at the beginning of the year. The residents of institution A demonstrated significant improvement in confidence (P = 0.00009) and knowledge (P = 0.0006) after completing the curriculum, with no improvement noted for residents at institution B in either confidence (P = 0.06) or knowledge (P = 0.79). Neither program demonstrated improvement in attitudes toward patient safety at the end of the year‐long curriculum.

Conclusion

Implementing a formal curriculum dedicated to PSQI led to an improvement in PSQI‐related project development confidence and PSQI knowledge. Attitudes toward safety did not improve over the course of a year. Longer‐term studies involving multiple institutions and other interventions are needed to evaluate the impact and duration of changes that occur.

Level of Evidence

1b Laryngoscope, 129:1100–1106, 2019
Deglutition and respiratory patterns during sleep in the aged with OSAS
Authors: Sato Kiminori , Chitose Shun‐ichi , Sato Fumihiko , Umeno Hirohito
Published: November 2018

Objective

Clearance of the pharynx by deglutition, which removes matter that could be aspirated, is important in protecting the airways and lungs against aspiration. The deglutition and respiratory phase patterns during sleep in the aged with obstructive sleep apnea syndrome (OSAS) were investigated.

Study Design

Retrospective study with case groups.

Methods

Ten aged adults with severe OSAS (average age 75, average apnea‐hypopnea index 43.8) were examined via time‐matched digital recordings of polysomnography and surface electromyography of the muscles (thyrohyoid and suprahyoid) related to swallowing and compared with aged adults without OSAS previously reported on.

Results

During sleep, swallowing was infrequent and absent for long periods. The median number of swallows per hour during total sleep time was 4.1 and the median longest deglutition‐free period was 70.5 minutes. Three‐fourths of deglutition occurred in association with respiratory electroencephalographic arousal. Deglutition was related to the sleep stage. The deeper the sleep stage, the lower the mean deglutition frequency. The median number of swallows per hour was 5.7 during stage N1 sleep and 2.8 during stage N2 sleep. There was no deglutition during stage N3 (deep) sleep. The median number of swallows per hour was 0.6 during REM sleep. Approximately 40% of swallows occurred after inspiration and approximately 42% were followed by inspiration.

Conclusion

Deglutition was infrequent and respiratory phase patterns were unique during sleep in the aged with OSAS. Sleep‐related deglutition and respiratory phase patterns may adversely influence aspiration‐related diseases (aspiration pneumonia, etc) in the aged with sleep‐related breathing disorders.

Level of Evidence

4
Muddy waters: An assessment of the suitability of zygocardiac ossicles for direct age estimation in the Giant mud crab Scylla serrata
Authors: Crook David A. , Adair Brendan J. , Grubert Mark A. , Saunders Thor M. , Morrongiello John R. , Douglas Michael M. , King Alison J.
Published: November 2018

A fundamental characteristic of calcified structures commonly used for direct age estimation in animals is that new material is accreted cumulatively and preserved across ontogeny, thus allowing growth marks to be reliably observed and counted. Direct age estimation in crustaceans has been problematic due to molting of calcified structures across ontogeny; however, recent studies suggest that gastric ossicle tissue is retained through molts and can be used for age estimation. We evaluate the use of sectioned gastric ossicles for direct aging of the Giant mud crab Scylla serrata. Sectioned zygocardiac ossicles from crabs collected in northern Australia are analyzed to determine: (1) whether putative annual age estimates can be reliably reproduced; (2) if age estimates are compatible with previous information; and (3) if ossicle growth is cumulative across ontogeny. Our analyses show that readability of putative annual increments in sectioned ossicles is poor and age estimates imprecise in comparison to fish otolith studies. Age‐at‐size estimates are broadly compatible with previous mark‐recapture data from the same regions. However, analyses of ossicle growth morphology suggest that the zygocardiac ossicles are either shed or extensively reworked during ontogeny, thus casting doubt on the utility of gastric ossicles for direct age estimation in this species. We conclude that the ontogenetic growth morphology of structures used for crustacean aging needs to be carefully considered and that detailed information on the timing and frequency of increment formation—and at least some understanding of the underlying processes—is required before this method is widely adopted.
Induced Transparency in Plasmon–Exciton Nanostructures for Sensing Applications
Authors: Krivenkov Victor , Goncharov Semyon , Nabiev Igor , Rakovich Yury P.
Published: November 2018

The effect of induced transparency, which is related to photoinduced bleaching of photoabsorbers, is being intensely studied and has many applications in the field of sensing. Along with this classical effect, numerous studies on induced transparency in coupled plasmon–exciton systems, which is accompanied by the formation of hybrid states, have been recently published. The formation of a new coupled system results in various spectral modifications. For example, induced transparency manifests itself as a narrow dip in the absorption spectrum of a coupled system. This effect can be used in sensing, the feasibility of which is the main objective here, where a variety of materials and methods for obtaining the induced transparency are considered. Various morphologies and geometries of plasmonic nanoparticles are discussed as well as types of molecular absorbers to assess the most favorable combinations for the evolvement of induced transparency. The potential applications of the induced transparency effect in sensing and molecular diagnostics are summarized.
Injectable Biodegradable Chitosan‐Alginate 3D Porous Gel Scaffold for mRNA Vaccine Delivery
Authors: Yan Jingxuan , Chen Ruying , Zhang Hong , Bryers James D.
Published: November 2018

mRNA vaccines have proven to be more stable, effective, and specific than protein/peptide‐based vaccines in stimulating both humoral and cellular immune response. However, mRNA's fast degradation rate and low‐transfection efficiency in vivo impede its potential in vaccination. Recent research in gene delivery has focused on nonviral vaccine carriers and either implantable or injectable delivery systems to improve transgene expression in vivo. Here, an injectable chitosan‐alginate gel scaffold for the local delivery of mRNA vaccines is reported. Gel scaffold biodegradation rates and biocompatibility are quantified. Scaffold‐mediated mRNA in vivo transgene expression as well as ovalbumin antigen specific cellular and humoral immune responses are evaluated in vivo. Luciferase reporter protein expression resulting from mRNA lipoplex‐loaded gel scaffolds is five times higher than systemic injection. Compared to systemic injections of naked mRNA or mRNA:lipoplexes, elevated levels of T cell proliferation and IFN‐γ secretion are seen with in vivo scaffold‐mediated mRNA lipoplex delivery. Furthermore, a humoral response (ovalbumin antigen specific IgG levels) is observed as early as week 1 for scaffold‐mediated mRNA lipoplex delivery, while protein‐based immunization did not elicit IgG production until 2 weeks post‐injection. Results suggest that injectable scaffold mRNA vaccine delivery maybe a viable alternative to traditional nucleic acid immunization methods.
Global existence versus blow‐up results for one dimensional compressible Navier–Stokes equations with Maxwell's law
Authors: Hu Yuxi , Wang Na
Published: November 2018

We consider one dimensional isentropic compressible Navier–Stokes equations with constitutive relation of Maxwell's law instead of Newtonion law. For this new model, we show that for small initial data, a unique smooth solution exists globally and converges to the equilibrium state as time goes to infinity. For some large data, in contrast to the situation for classical compressible Navier–Stokes equations, which admits global solutions, we show finite time blow up of solutions for the relaxed system. Moreover, we prove the compatibility of the two systems in the sense that, for vanishing relaxation parameters, the solutions to the relaxed system are shown to converge to the solutions of classical system.
Enhancing signal‐to‐noise ratio and resolution in low‐field NMR relaxation measurements using post‐acquisition digital filters
Authors: Monaretto Tatiana , Souza Andre , Moraes Tiago Bueno , Bertucci‐Neto Victor , Rondeau‐Mouro Corinne , Colnago Luiz Alberto
Published: November 2018

The traditional way to enhance signal‐to‐noise ratio (SNR) of nuclear magnetic resonance (NMR) signals is to increase the number of scans. However, this procedure increases the measuring time that can be prohibitive for some applications. Therefore, we have tested the use of several post‐acquisition digital filters to enhance SNR up to one order of magnitude in time domain NMR (TD‐NMR) relaxation measurements. The procedures were studied using continuous wave free precession (CWFP‐T1) signals, acquired with very low flip angles that contain six times more noise than the Carr–Purcell–Meiboom–Gill (CPMG) signal of the same sample and experimental time. Linear (LI) and logarithmic (LO) data compression, low‐pass infinity impulse response (LP), Savitzky–Golay (SG), and wavelet transform (WA) post‐acquisition filters enhanced the SNR of the CWFP‐T1 signals by at least six times. The best filters were LO, SG, and WA that have high enhancement in SNR without significant distortions in the ILT relaxation distribution data. Therefore, it was demonstrated that these post‐acquisition digital filters could be a useful way to denoise CWFP‐T1, as well as CPMG noisy signals, and consequently reducing the experimental time. It was also demonstrated that filtered CWFP‐T1 method has the potential to be a rapid and nondestructive method to measure fat content in beef and certainly in other meat samples.
Motion‐robust diffusion compartment imaging using simultaneous multi‐slice acquisition
Authors: Marami Bahram , Scherrer Benoit , Khan Shadab , Afacan Onur , Prabhu Sanjay P. , Sahin Mustafa , Warfield Simon K. , Gholipour Ali
Published: November 2018

Purpose

To achieve motion‐robust diffusion compartment imaging (DCI) in near continuously moving subjects based on simultaneous multi‐slice, diffusion‐weighted brain MRI.

Methods

Simultaneous multi‐slice (SMS) acquisition enables fast and dense sampling of k‐ and q‐space. We propose to achieve motion‐robust DCI via slice‐level motion correction by exploiting the rigid coupling between simultaneously acquired slices. This coupling provides 3D coverage of the anatomy that substantially constraints the slice‐to‐volume alignment problem. This is incorporated into an explicit model of motion dynamics that handles continuous and large subject motion in robust DCI reconstruction.

Results

We applied the proposed technique, called Motion Tracking based on Simultanous Multislice Registration (MT‐SMR) to multi b‐value SMS diffusion‐weighted brain MRI of healthy volunteers and motion‐corrupted scans of 20 pediatric subjects. Quantitative and qualitative evaluation based on fractional anisotropy in unidirectional fiber regions, and DCI in crossing‐fiber regions show robust reconstruction in the presence of motion.

Conclusion

The proposed approach has the potential to extend routine use of SMS DCI in very challenging populations, such as young children, newborns, and non‐cooperative patients.
Micromechanical modeling of cohesive thermoelastic steady‐state and transient cracking in polycrystalline materials
Authors: Geraci G. , Aliabadi M. H.
Published: November 2018

In this paper, a micromechanical formulation is proposed for modeling thermoelastic intergranular and transgranular damage and microcracking evolution in brittle polycrystalline materials. The model is based on a multiregion boundary element approach combined with the dual boundary element formulation. Polycrystalline microstructures are created through a Voronoi tessellation algorithm. Each crystal has an elastic isotropic behavior, and multiphase aggregates have been considered. Damage evolution along (intergranular or transgranular) interfaces is modeled using thermomechanical cohesive laws, and upon failure, nonlinear frictional contact analysis is introduced to model separation, stick or slip. Steady‐state and transient thermoelastic formulations have been modeled, and numerical simulations are presented, not only to demonstrate the validity but also to study the physical implications of the proposed formulation, in comparison with other numerical methods as well as experimental observations and literature results.
Epoxy functionalized multi‐walled carbon nanotubes/polyvinylidene fluoride nanocomposites: Microstructure, morphology, thermal, piezoelectricity and conductivity investigations
Authors: Begum Saddiqa , Ullah Hameed , Kausar Ayesha , Siddiq Mohammad , Aleem Muhammad Adeel
Published: November 2018

Multi‐walled carbon nanotubes (MWCNTs) were modified by grafting to di‐glycidyl ether of bisphenol‐A (DGEBA) through 4,4′‐diaminodiphenylsulfone functionality, and subsequently were used as reinforcement in polyvinylidene fluoride (PVDF) to fabricate ef‐MWCNTs/PVDF nanocomposites for the very first time. Comparing to the nonfunctionalized pristine MWCNTs (p‐MWCNTS) and acyl chloride‐modified MWCNTs (ac‐MWCNTs), the ef‐MWCNTs have shown better and enhanced dispersion into the PVDF matrix, owing to the better interface formation due to the improved interaction between the tubes and the polymer chains. Consequently, the ef‐MWCNTs/PVDF nanocomposites have shown higher melting temperature (Tm) corresponding to the increased β‐phase fraction formation. This was also reflected in the piezoelectric analyses in which the ef‐MWCNTs/PVDF nanocomposites have shown increased β‐phase dependent piezoelectric constant, d33, reaching above 8.0 PC/N comparing to 5.0 PC/N in case of ac‐MWCNTs/PVDF. Similarly, a reverse trend has been observed after the percolation threshold in the conductivity of ac‐MWCNTs/PVDF nanocomposites. Contrarily, the conductivity of ef‐MWCNTs/PVDF nanocomposites have shown a regular increase after the percolation threshold with increasing ef‐MWCNTs wt% loading. In a nutshell, we have achieved better dispersion even at highest applied wt% loadings of MWCNTs into PVDF matrix upon functionalizing with epoxy, corresponding to strong interfacial interactions between the tubes and polymer chains. POLYM. COMPOS., 40:E776–E794, 2019. © 2018 Society of Plastics Engineers
Preparation of pH‐sensitive hydrogels by graft polymerization of itaconic acid on tragacanth gum
Authors: Verma Chetna , Negi Poonam , Pathania Deepak , Sethi Vipula , Gupta Bhuvanesh
Published: November 2018

Graft polymerization of itaconic acid on tragacanth gum (TG) was carried out using potassium persulfate as initiator to develop smart hydrogels for drug delivery systems. The effect of the grafting parameters on the degree of grafting was investigated. The grafting was significantly influenced by the reaction medium, the reaction temperature and the monomer concentration. The monomer dependency of the system was found to be 1.52. The hydrogels were characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry and X‐ray diffraction. The grafted TG had an amorphous nature and exhibited excellent swelling in water and strong dependence on the pH of the medium. The grafted TG showed pH‐dependent release of ciprofloxacin which offers the possibility of using these materials in colon‐specific drug targeting for human healthcare systems. © 2018 Society of Chemical Industry
Real‐Time Detection of Nanoparticles Interaction with Lipid Membranes Using an Integrated Acoustical and Electrical Multimode Biosensor
Authors: Lu Yao , Zhang Hao , Wang Zhan , Jeong Sundo , Jo Min‐Chul , Park Myoung‐Hwan , Duan Xuexin
Published: November 2018

Understanding interactions of nanoparticles with biomembranes is critical in nanomedicine and nanobiotechnology. The underlying mechanisms still remain unclear due to the fact that there are no reliable tools to follow such complex processes. In this work, the interactions between gold nanoparticles (AuNPs) and the supported lipid bilayer (SLB) are monitored in situ by a multimode biosensor integrating a quartz crystal microbalance with dissipation function (QCM‐D) and a field effect transistor (FET). Real‐time responses of frequency shift (Δf), dissipation (ΔD), and ion current (ΔI) are simultaneously recorded to provide complementary information for AuNPs translocation across the SLB. The combined mass loading, mechanical and electrical measurements reveal the dynamics of the particle–membrane interactions as well as the formation of transient pores or permanent defects in the membrane. AuNPs with different diameters, surface charge, and ligand properties are used to study their translocation behaviors, including adsorption on or desorption from the membrane surface, diffusion into or penetration through the lipid bilayer. This multimode sensing approach provides insights into the mechanism of the particle–membrane interactions and suggests a method of label‐free screening of nanomaterials' interaction with model membranes in a real‐time manner.
Influence of Thermal Annealing on Ultrafast Laser‐Induced Local Densification in Bulk Sulfur‐Based Chalcogenide Glasses
Authors: Somayaji Madhura , D'Amico Ciro , Wu Yiming , Troles Johann , Stoian Razvan
Published: November 2018

The response to focused ultrafast laser pulses, of three bulk sulfur‐based chalcogenide glasses, gallium lanthanum sulfide (GLS) and two germanium arsenic sulfide with different stoichiometry (Ge20As20S60 and Ge15As15S70), is studied as a function of a thermal treatment made by several annealing cycles under the glass transition temperature. It is demonstrated that the annealing procedure has a considerable influence on the ultrafast laser‐induced local densification process of the quenched glasses. Using post‐mortem phase contrast microscopy and single‐mode light guiding measurements on photo‐inscribed waveguides, the influence of the thermal history on the laser‐induced positive refractive index changes (local densification) is determined. In particular it is shown that, in the case of the Ge20As20S60 glass, the threshold of ultrafast laser‐induced densification in terms of laser energetic dose is considerably lowered after the first annealing cycle. In the light of this result, the activation of a new relaxation channel during the thermal treatment and its influence on the laser‐induced densification process of Ge‐As‐S glasses is discussed. Potential of material thermal pre‐treatment for developing efficient photo‐inscription techniques in the domain of integrated photonics is also discussed.
Characterization and Formation Mechanism of the Nanodiamond Synthesized by A High Energy Arc‐Plasma
Authors: Zhou Lei , Zhao Yang , Huang Hao , Gan Xiaorong , Javid Muhammad , Xue Fanghong , Yu Hongtao , Dong Xinglong , Quan Xie
Published: November 2018

A new fabrication strategy using thermal source of DC arc‐discharge plasma is developed in the synthesis of nanodiamond particles. In the fabrication process, a solid mixture of Ni/Si/graphite coarse powders is used as the raw materials, meanwhile the gaseous mixture of H2/Ar served as the preparation atmosphere. The well‐established arc‐discharge plasma is significant in operation under a low gaseous pressure and an acceptable energy condition, and would be potential to become a novel process for synthesis of nanodiamond particles in large scale. The initially formed SiC clusters and the solid solution of Ni(C) particles are crucial in serving as crystal nuclei of diamond and an in situ carbon source which can gradually be released with cooling, respectively. Structural characterizations by high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), Raman spectra, and X‐ray diffraction (XRD) confirm the existence nanodiamond particles, they are typically spherical with 5–20 nm in size. The formation of such nanodiamond particles by the arc‐discharge thermal source is discussed in detail on the knowledge of binary phase diagram, constitution of raw materials, and nucleation/growth processes under the experimental conditions.
Perfect Absorption in One–Dimensional Photonic Crystal with Graphene‐Dielectric Hyperbolic Metamaterials
Authors: Ju Lu , Xie Xun , Du Wei‐Chen , Liu Yu‐Jie , Hao Jiong‐Ju , Ma Bao‐Liang , Yang Hong‐Wei
Published: November 2018

The absorption characteristics of one‐dimensional photonic crystals (1DPC) consisting of an ordinary dielectric and graphene–dielectric hyperbolic metamaterials in terahertz (THz) are theoretically analyzed and numerically simulated using the transfer matrix method. The perfect absorption peaks can be achieved in the structure designed in our research. In the 1DPC, the dielectric layers are embedded into graphene layers and the optical axis of the graphene–dielectric hyperbolic metamaterials is normal to the graphene layers. The graphene–dielectric layers are seen as anisotropic effective medium and possess the properties of hyperbolic dispersion in THz frequency band. The locations of perfect absorptance peaks are dependent on chemical potential, the thicknesses of dielectric layers and the inclined angle. The positions of absorption peaks are blue‐shifted with increasing the chemical potential and red‐shifted by increasing the thicknesses of the dielectric layers. We testified that the orientation of the optical axis of the graphene–dielectric layers has prominent effect on the locations of the perfect absorption peaks. Moreover, multiband absorption peaks can be obtained by introducing more structure as given in our research with different parameters. The controllable perfect absorption achieved at the far infrared ray (FIR) frequencies could be applied in the design of multichannel perfect absorption filters.
Synoptic climatology of hybrid cyclones in the Australian region
Authors: Quinting Julian F. , Catto Jennifer L. , Reeder Michael J.
Published: November 2018

In May and September 2016, two intense hybrid cyclones (HCs) developed over the Great Australian Bight damaging infrastructure and causing a state‐wide power outage in South Australia. These two cyclones motivate the compilation of the first synoptic climatology of HCs in the Australian region, including an analysis of their importance for wind and precipitation extremes, and a composite view of the large‐scale flow in which they develop. HCs are identified in ERA‐Interim data from 1979 to 2010 using an objective feature tracking method and a cyclone phase space diagnostic. HCs exhibit a pronounced seasonal cycle with most of them occurring from May to September. During these months, HCs are most frequent over the Tasman Sea and the Great Australian Bight where they account for 50% of all cyclones. A common characteristic of all HCs is that the strongest precipitation, which is locally extreme in 91% of all HCs, falls in the warm sector and along a bent‐back warm front on the poleward side of the cyclones. Moreover, the area affected by extreme precipitation and the maximum precipitation in HCs are no different from non‐hybrid cyclones (NHCs). In contrast, the area affected by extreme wind gusts is significantly larger in HCs than for NHCs. In both HCs and NHCs the strongest near‐surface wind gusts typically occur in the cold air mass in the wake of the cyclones, especially in those over the Great Australian Bight. The upper‐tropospheric structure of HCs is characterized by an elongated cyclonic potential vorticity anomaly embedded between two ridges that eventually cuts off. In contrast, NHCs are characterized by a zonal flow upstream and upper‐tropospheric cyclonic wave breaking.
Source term estimation of a hazardous airborne release using an unmanned aerial vehicle
Authors: Hutchinson Michael , Liu Cunjia , Chen Wen‐Hua
Published: November 2018

Gaining information about an unknown gas source is a task of great importance with applications in several areas, including responding to gas leaks or suspicious smells, quantifying sources of emissions, or in an emergency response to an industrial accident or act of terrorism. In this paper, a method to estimate the source term of a gaseous release using measurements of concentration obtained from an unmanned aerial vehicle (UAV) is described. The source term parameters estimated include the three‐dimensional location of the release, its emission rate and other important variables needed to forecast the spread of the gas using an atmospheric transport and dispersion model. The parameters of the source are estimated by fusing concentration observations from a gas detector on‐board the aircraft, with meteorological data and an appropriate model of dispersion. Two models are compared in this paper, both derived from analytical solutions to the advection–diffusion equation. Bayes’ theorem, implemented using a sequential Monte Carlo algorithm, is used to estimate the source parameters to take into account the large uncertainties in the observations and formulated models. The system is verified with novel, outdoor, fully automated experiments, where observations from the UAV are used to estimate the parameters of a diffusive source. The estimation performance of the algorithm is assessed subject to various flight path configurations and wind speeds. Observations and lessons learned during these unique experiments are discussed, and areas for future research are identified.
Synthesis, Characterization, Photophysical and Electrochemical Studies of Ruthenium(II) Complexes with 4′‐Substituted Terpyridine Ligands and Their Biological Applications
Authors: Ezhilarasu Tamilarasu , Balasubramanian Sengottuvelan
Published: November 2018

Three 4′‐(4‐Methylbenzoate‐benzyloxy)‐2,2′:6′,2′′‐terpyridine (MBBtpy), 4′‐(4‐Ethylbenzoate‐benzyloxy)‐2,2′:6′,2′′‐terpyridine (EBBtpy) and 4′‐(5‐(1,3‐Dimethylbenzoate)‐benzyloxy)‐2,2′:6′,2′′‐terpyridine (DMBBtpy) ligands and seven ruthenium(II) symmetrical [Ru(MBBtpy)2](PF6)2(Ru1), [Ru(EBBtpy)2](PF6)2(Ru2), [Ru(DMBBtpy)2](PF6)2(Ru3) and unsymmetrical [Ru(MBBtpy)(EBBtpy)](PF6)2(Ru4), [Ru(MBBtpy)(ttpy)](PF6)2(Ru5), [Ru(MBBtpy)(Brttpy)](PF6)2(Ru6), [Ru(MBBtpy)(HOttpy)](PF6)2(Ru7) complexes were synthesized and characterized by UV/Vis, Fluorescence, FTIR,1H &13C NMR, ESI‐mass spectral studies and electrochemical studies. The crystal structure of HOttpy ligand was determined by single crystal X‐ray diffraction. The cyclic voltammograms of Ru(II) complexes exhibit a quasi‐reversible oxidation peak corresponding to RuII/RuIIIprocess. The peak currentIpaandIpcincreases with increase in scan rate. The Ru(II) complexes tested forin vitroantimicrobial activity against four human pathogens and fungusCandida albicansshowed good antibacterial and antifungal activity. The binding of Ru(II) complexes with calf thymus DNA was determined by UV/Vis spectroscopy. The cleavage activity of ruthenium(II) complexes studied by gel electrophoresis indicates that these complexes can cleave pUC19 DNA more efficiently when compared to that of control.
CuOx‐TiO2 Composites: Electronically Integrated Nanocomposites for Solar Hydrogen Generation
Authors: Bharad Pradnya A. , Nikam Arun V. , Thomas Femi , Gopinath Chinnakonda S.
Published: November 2018

CuOx‐TiO2 (CT) composites were prepared by different methods (impregnation, microwave and photodeposition methods) and evaluated for solar water splitting (SWS) with aqueous methanol. CT composites prepared by three different methods were characterized by relevant methods to understand the correlation between synthesis method and activity, and the mechanism of water splitting. A comparison of photocatalytic activity of CT composite materials indicates that the photocatalyst prepared by photodeposition method shows significantly improved activity for hydrogen production from aqueous methanol as well as with water (overall water splitting) under one sun conditions. Cu is present in Cu/Cu+1 form in photodeposition method prepared CT, which is more effective and helpful for solar light absorption as well as charge carrier separation due to the formation of bulk p‐n (Cu2O‐TiO2) heterojunctions. However, CuO formation seems to decrease the activity with other preparation methods.
Betti Bases from 4‐(3‐Pyridazo)‐1‐naphthol: Synthesis, Coordination Behaviour and Unusual Substitution Reactions
Authors: Kurteva Vanya B. , Lubenov Lubomir A. , Shivachev Boris L. , Nikolova Rositsa P. , Fromm Katharina M.
Published: November 2018

A series of Betti bases from 4‐(3‐pyridyl)azo‐1‐naphthol dye, possessing flexible methylene or more constrained aryl‐methyne spaced NH‐containing side‐chains, were obtained and characterized. It was shown by NMR spectroscopy that the ligands exist in keto form. The products’ structure was confirmed by single crystal XRD of a selected sample. A study on the coordination ability of the ligands with silver(I) was performed, leading to an unexpected substitution reaction.
Organic Matrix Stabilized Ultra‐Fine Bismuth Oxide Particles for Electrochemical Energy Storage Application
Authors: Devi Nishu , Ghosh Sarit , Ray Sekhar C , Mallick Kaushik
Published: November 2018

The synthesis of an organic‐inorganic supramolecular hybrid system has been reported, using a wet‐chemical synthesis method, where the Bi2O3 nanoparticles are dispersed within the organic matrix. The XRD analysis showed the formation of crystalline Bi2O3. The XPS and Raman spectra analysis also confirmed the formation of Bi2O3. In this work, the organic molecule supported nanosized Bi2O3 has been used as an electrode material for supercapacitor application in presence of the aqueous solution of alkaline electrolyte (1.0 mol dm−3 of KOH) and exhibited a specific capacitance 407 F.g−1 along with the energy density value of 113 W.h.kg−1 at 1 A.g−1. The supramolecular system exhibited a long‐term stability by retaining 89% of the initial specific capacitance value after 500 cycles at the current density of 5 A.g−1.
A new Zn mixed‐ligand coordination polymer fiber for solid‐phase microextraction of the anticancer drug tamoxifen
Authors: Jafari Mostafa , Amani Vahid
Published: November 2018

A new metal‐organic coordination polymer, [Zn(μ‐mptrz)(mptrz)(μ‐en)0.5]n (mptrz− is 4‐methyl‐1,2,4‐triazole‐3‐thiolato), has been used to prepare a solid‐phase microextraction fiber using the direct immersion method. The fiber was well characterized, and showed superior properties. Scanning electron microscopy of the fiber shows a very porous and homogenous coating. The thermal stability, adhersivity and chemical stability were excellent for extracting analytes from harsh media and desorbing them in a high thermal inlet of a gas chromatograph. An anti‐cancer drug, tamoxifen, was extracted with this fiber and then analyzed by using gas chromatography with flame ionization detection. The main factors affecting the extraction of tamoxifen were optimized. The detection limit and linear range were 0.62 and 4–800 μg L−1, respectively. The intra‐day and inter‐day relative standard deviations were obtained at different concentrations, using a single fiber, and found to be 14.1–15.4 and 13.3%, respectively. The results were then compared with other works. Tamoxifen in two urine samples was successfully analyzed with the proposed method.
Structural behavior of profiled dry joints between precast ultra‐high performance fiber reinforced concrete elements
Authors: Oettel Vincent , Empelmann Martin
Published: November 2018

The very high‐compressive strength of ultra‐high performance fiber reinforced concrete (UHPFRC) as well as its enormous durability facilitate innovative design and construction of thin‐walled and weight‐optimized elements. Because the mixing and casting of UHPFRC are demanding processes, such elements are preferably precast. An auspicious construction method is joining weight‐ and transport‐optimized UHPFRC precast elements to segmental prestressed structures such as segmental bridges, precast towers or precast poles. For the safety of these structures, the structural behavior of the joints between adjacent UHPFRC segments is fundamental. Therefore, experimental and theoretical research on the load bearing capacity of profiled dry joints of precast UHPFRC segments are carried out at the iBMB, Division of Concrete Construction of the TU Braunschweig. Using the results of slant shear tests under monotonic loading, different calculation approaches are evaluated and a modified approach is proposed.