bluuebunny/crossref_metadata_2025 huggingface dataset:
T7 Expression Systems for Inducible Production of Proteins from Cloned Genes in E. coli
Authors: Studier F. William
Published: July 2018

Inducible T7 expression systems are capable of producing a wide range of proteins in E. coli. Improvements over common practice include: (1) preventing unintended induction by establishing and maintaining expression strains in non‐inducing growth media composed entirely of purified components instead of complex growth media that may variably induce target proteins on approach to saturation; and (2) expressing many target proteins in parallel by convenient and productive auto‐induction in BL21(DE3) and other suitable hosts, instead of IPTG induction. From the earliest days, basal expression prevented establishment of inducible strains for producing proteins that are stressful to the host. Newly developed pAL vectors now reduce basal expression to levels where coding sequences for even the most stressful proteins can be maintained and induced. Asymmetric ligation allows simple and efficient cloning of individual coding sequences or simultaneous cloning of two or three coding sequences for co‐expression from a single pAL vector. © 2018 by John Wiley & Sons, Inc.
Genetic Manipulation of Cryptococcus neoformans
Authors: Jung Kwang‐Woo , Lee Kyung‐Tae , So Yee‐Seul , Bahn Yong‐Sun
Published: July 2018

Cryptococcus neoformans is an opportunistic fungal pathogen, which causes life‐threatening meningoencephalitis in immunocompromised individuals and is responsible for more than 1,000,000 infections and 600,000 deaths annually worldwide. Nevertheless, anti‐cryptococcal therapeutic options are limited, mainly because of the similarity between fungal and human cellular structures. Owing to advances in genetic and molecular techniques and bioinformatics in the past decade, C. neoformans, belonging to the phylum basidiomycota, is now a major pathogenic fungal model system. In particular, genetic manipulation is the first step in the identification and characterization of the function of genes for understanding the mechanisms underlying the pathogenicity of C. neoformans. This unit describes protocols for constructing target gene deletion mutants using double‐joint (DJ) PCR, constitutive overexpression strains using the histone H3 gene promoter, and epitope/fluorescence protein‐tagged strains in C. neoformans. © 2018 by John Wiley & Sons, Inc.
Continuous Flow for the Photochemical C‐H Amination of Arenes
Authors: Cosgrove Sebastian C. , Douglas Gayle E. , Raw Steven A. , Marsden Stephen P.
Published: July 2018

The direct C−H amination of arenes by aminium radicals generated by photolysis of N‐chloroamines is demonstrated under continuous flow conditions. The reactions proceed with comparable efficiency to small scale batch processes but are superior to larger scale batch operations. The continuous generation of the N‐chloroamine from the amine precursor can be integrated into the process, facilitating the continuous direct conversion of secondary amines to their arylated derivatives.
FPGA implementation of adaptive time delay estimation for real‐time near‐field electromagnetic ranging
Authors: Wang Peng , Zhang Xiaotong , Liu Zhiyang , Xu Liyuan , He Jie , Xu Jinwu
Published: July 2018

The near‐field electromagnetic ranging systems exploit the near‐field phase behavior of low frequency signals for indoor real‐time ranging. Conventionally, phase detector is used to determine the phase of electric and magnetic fields. Subsequently, the phase difference is used to estimate a distance value. In adaptive time delay estimation approach, the time delay between electric and magnetic signals is used instead of phase difference for an estimation. This method does not require a priori knowledge of the transmitting signals and can obtain better performance in low signal‐to‐noise ratio environment. In this paper, we propose a digital near‐field electromagnetic ranging system design and implement it on field‐programmable gate array. This system is composed of time delay estimator, frequency estimator, and received signal strength indicator. A maximum correntropy criterion–based explicit time delay estimation algorithm with a delay in the coefficient update is implemented to estimate the time delay in real time. The fast Fourier transform and received signal strength indicator modules determine the signal frequency and the signal strength received, respectively. Our experimental results indicate that the delayed maximum correntropy criterion–based explicit time delay estimation algorithm has fast convergence rate and good steady‐state performance in an impulsive noise environment.
Phytoestrogens in soy‐based meat substitutes: Comparison of different extraction methods for the subsequent analysis by liquid chromatography‐tandem mass spectrometry
Authors: Benedetti Barbara , Di Carro Marina , Magi Emanuele
Published: July 2018

This paper presents the development of an efficient extraction procedure followed by a high performance liquid chromatography‐tandem mass spectrometry (HPLC‐MS/MS) method for the determination of five phytoestrogens (genistein, daidzein, formononetin, biochanin A, and coumestrol) in soy‐based meat substitutes. Phytoestrogens are considered endocrine disrupting compounds, and their quantification is important in soy‐based products, whose diffusion is increasing nowadays.

The HPLC‐MS/MS method, with electrospray ionization (ESI) source, was optimized to obtain high specificity and sensitivity, as well as rapidity of the analysis. Three extraction techniques were applied to soy burgers and compared: ultrasound assisted extraction, ultrasound assisted extraction followed by solid phase extraction and the Quick Easy Cheap Effective Rugged and Safe (QuEChERS) methodology. Both ultrasound assisted extraction and QuEChERS proved to be suitable for the determination of phytoestrogens, showing high recoveries, in the range of 86% to 99% and 75% to 105%, respectively. Matrix effect was evaluated, and ion suppression was observed for coumestrol and formononetin, demonstrating the importance of matrix effect assessment when complex samples are analyzed by HPLC‐ESI‐MS.

The complete analytical protocols provided limits of detection and quantitation in soy‐burgers at the ng g−1 level for all the considered phytoestrogens. Some soy burger samples were analyzed by both ultrasound assisted extraction and QuEChERS followed by HPLC‐MS/MS. High concentration levels of daidzein and genistein (2‐59 μg g−1 and 2‐72 μg g−1, respectively) were found; formononetin was in the range of 5 to 26 ng g−1, while biochanin A and coumestrol were under the limit of quantitation in all samples. The results obtained with the two different sample treatment were in good agreement, proving the precision and accuracy of the described techniques.
A systematic approach toward comparing electrospray ionization efficiencies of derivatized and non‐derivatized amino acids and biogenic amines
Authors: Gornischeff Artur , Liigand Jaanus , Rebane Riin
Published: July 2018

Ionization efficiency (IE) in mass spectrometry (MS) has been studied for many different compounds, and different IE scales have been constructed in order to quantitatively characterize IE. In the case of MS, derivatization has been used to increase the sensitivity of the method and to lower the limits of detection. However, the influence of derivatization on IE across different compounds and different derivatization reagents has not been thoroughly researched, so that practitioners do not have information on the IE‐enhancing abilities of different derivatization reagents.

Moreover, measuring IE via direct infusion of compounds cannot be considered fully adequate. Since derivatized compounds are in complex mixtures, a chromatographic method is needed to separate these compounds to minimize potential matrix effects.

In this work, an IE measurement system with a chromatographic column was developed for mainly amino acids and some biogenic amines. IE measurements with liquid chromatography electrospray ionization mass spectrometry (LC/ESI/MS) were carried out, and IE scales were constructed with a calibration curve for compounds with and without derivatization reagent diethyl ethoxymethylenemalonate. Additionally, eluent composition effects on ionization were investigated.

Results showed that derivatization increases IE for most of the compounds (by average 0.9 and up to 2‐2.5 logIE units) and derivatized compounds have more similar logIE values than without derivatization. Mobile phase composition effects on ionization efficiencies were negligible. It was also noted that the use of chromatographic separation instead of flow injection mode slightly increases IE.

In this work, for the first time, IE enhancement of derivatization reagents was quantified under real LC/ESI/MS conditions and obtained logIE values of derivatized compounds were linked with the existing scale.
Synthesis and characterization of a poly(p‐phenylenediamine)‐based electrospun nanofiber for the micro‐solid‐phase extraction of organophosphorus pesticides from drinking water and lemon and orange juice samples
Authors: Mehrani Zahra , Ebrahimzadeh Homeira , Asgharinezhad Ali Akbar
Published: July 2018

A new micro‐solid‐phase extraction sorbent was synthesized by electrospinning poly(p‐phenylenediamine)/poly(vinyl alcohol) in the presence of cetyltrimethylammonium bromide. The modified nanofiber was prepared by removing the majority of the poly(vinyl alcohol) from the nanofiber blend by exposing it to the hot water. Scanning electron microscopy and surface analysis were performed to study the homogeneity and porosity of the electrospun nanofiber. In addition, Fourier transform infrared spectroscopy was applied for more characterization. The capability of the new nanofiber was explored by applying it in the extraction and preconcentration of organophosphorus pesticides from aqueous medium. After solvent desorption, the extracted analytes were analyzed by high‐performance liquid chromatography with diode array detection. Under the optimum conditions, the relative standard deviation values at the concentration level of 50 ng/mL were in the range of 4.8–8.3%. The calibration curve showed linearity in the range of 0.5–500 ng/mL, and the limits of detection (S/N = 3) for the studied compounds were 0.15 ng/mL. By analyzing Tehran drinking water, lemon juice, sour lemon juice, orange juice and sour orange juice, the applicability of the presented method was investigated and the relative recoveries were in the range of 76–102%.
Development of Bioink from Decellularized Tendon Extracellular Matrix for 3D Bioprinting
Authors: Toprakhisar Burak , Nadernezhad Ali , Bakirci Ezgi , Khani Navid , Skvortsov Gozde Akdeniz , Koc Bahattin
Published: July 2018

Using decellularized extracellular matrix (dECM) hydrogels as bioinks has been an important step forward for bioprinting of functional tissue constructs, considering their rich microenvironment and their high degree of biomimicry. However, directly using dECM hydrogels as bioinks may not be suitable for bioprinting processes because of the loss of shape fidelity and geometrical precision of bioprinted structure due to their slow gelation kinetics. In this article, the development and direct bioprinting of dECM hydrogel bioink from bovine Achilles tendon were presented. The developed bioink is used for a microcapillary‐based bioprinting process without any support structure and/or any additional cross‐linker components. The reported decellularization and solubilization methods yield dECM pre‐gels which turn into stable hydrogels in a short time at physiological conditions. The gelation kinetics and mechanical strength of bioinks with different concentrations and digestion times are characterized. A support structure‐free 3D bioprinting of the developed bioink is shown by aspirating dECM bioinks and then in situ gelation and extrusion through a fine microcapillary nozzle. The viability assays indicate that the developed dECM bioink has no cytotoxic effect on encapsulated NIH 3T3 cells and the cells show lineage‐specific morphology in the early days of culture as well.
Preparation and Gas Separation Properties of Spirobichroman‐Based Polyimides
Authors: Zhang Caili , Li Pei
Published: July 2018

Polymers with rigid and contorted structures are always preferred for use as gas separation membranes. Owing to the contorted nature of the spiro‐center, the spirobichroman structure is an effective scaffold for impeding polymer chain packing. Two spirobichroman‐based diamines, 6,6′‐bis(4‐amino‐2‐trifluoromethylphenoxy)‐4,4,4′,4′,7,7′‐hexamethyl‐2,2′‐spirobichroman (FSBC) and 6,6′‐bis(4‐aminophenoxy)‐4,4,4′,4′,7,7′‐hexamethyl‐2,2′‐spirobichroman (SBC), with or without CF3 side groups are prepared. The two diamines are separately reacted with 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (BTDA) and 3,3′,4,4′‐diphenylsulfonetetracarboxylic dianhydride (DSDA) to obtain four spirobichroman‐based polyimides, denoted as BTDA‐FSBC, BTDA‐SBC, DSDA‐FSBC, and DSDA‐SBC. The different molecular structures among the four monomers are expected to alter the fractional free volume of the corresponding polyimides by impacting chain‐packing conditions, and then controlling the gas transport properties. Chemical structures, thermal and physical properties of the polyimides are fully characterized. Two different methods, molecular dynamics simulation and Bondi's group contribution method are employed to characterize the fractional free volumes (FFVs) of these polyimides. In the end, it is found that FSBC‐based polyimides exhibit relatively higher gas permeability than SBC‐based polyimides.
Convenient Graphical Visualization of Messages Encoded in Sequence‐Defined Synthetic Polymers Using Kendrick Mass Defect Analysis of their MS/MS Data
Authors: Poyer Salomé , Fouquet Thierry , Sato Hiroaki , Lutz Jean‐François , Charles Laurence
Published: July 2018

Kendrick mass defect (KMD) analysis is shown here to be a convenient method to read binary messages encoded in the structure of two types of sequence‐defined synthetic polymers, namely, polyurethanes and poly(alkoxyamine phosphodiester)s. KMD analysis allows graphical ranking of mass data obtained for species containing repeating units. This is performed on MS/MS data in which distribution of fragments reveals the comonomer sequence of digital macromolecules. Choosing one coding monomer as the base unit, KMD computation of MS/MS data leads to stair‐like plots where flat steps correspond to that monomer selected as the base unit while oblique steps reveal the other monomer. To correct for any point misalignments resulting from slight inaccuracy of fragment mass measurement, fractional base units are used to perform resolution‐enhanced KMD (RE‐KMD) analysis. As the length of the chain increased, a procedure aiming at correct aliased points is also implemented to achieve continuous, more convenient, stair‐like plots.
A Tunable Nanoimprint System to Create New Features
Authors: Zhang Xiang , Hu Xin , Shen Lei , Chen Xinrui , Ge Haixiong
Published: July 2018

Fabrication of different patterns based on the same nanoimprint mould is very attractive due to the time and cost consumption of fabricating hard mould. This paper demonstrates a tunable photo‐curing nanoimprint system to create new features based on the same polydimethylsiloxane (PDMS) mould and a Ti‐containing resist synthesized by titanium (IV) ethoxide and 2‐(methacryloyloxy)ethyl acetoacetate. The resist exhibits very high oxygen RIE resistance and is able to take the place of traditional polysiloxance based resists to fabricate high‐aspect‐ratio patterns. The resist also has a low shrinkage (about 2.45%) and a high Young’s modulus of 10.85 GPa after photo‐curing. High polarity contrast of PDMS and Ti‐resist makes the release process freely and PDMS mould can be directly used without further anti‐stick treatment. A number of new features are imprinted into Ti‐resist based on the same PDMS mould by controlling the deformation and the stretched PDMS mould can be repeatedly used after relaxation.
A robust intensity modulated proton therapy optimizer based on Monte Carlo dose calculation
Authors: Ma Jiasen , Wan Chan Tseung Hok Seum , Herman Michael G. , Beltran Chris
Published: July 2018

Purpose

Accuracy of dose calculation models and robustness under various uncertainties are key factors influencing the quality of intensity modulated proton therapy (IMPT) plans. To mitigate the effects of uncertainties and to improve the dose calculation accuracy, an all‐scenario robust IMPT optimization based on accurate Monte Carlo (MC) dose calculation was developed.

Methods

In the all‐scenario robust IMPT optimization, dose volume histograms (DVHs) were computed for the nominal case and for each uncertainty scenario. All scenarios were weighted by DVH values dynamically throughout optimization iterations. In contrast, probabilistic approach weighted scenarios with fixed scenario weights and worst case optimizations picked one single scenario — the worst scenario for each iteration. Uncertainties in patient setup and proton range were considered in all clinical cases studied. Graphics processing unit (GPU) computation was employed to reduce the computational time in both the MC dose calculation and optimization stages. A previously published adaptive quasi‐Newton method for proton optimization was extended to include robustness. To validate the all‐scenario algorithm extension, it was compared with the single scenario optimization target volume (OTV) based approach in clinical cases of three different disease sites. Additional comparisons with worst case optimization methods were conducted to evaluate the performance of the all‐scenario robust optimization against other robust optimizations.

Results

The all‐scenario robust IMPT optimization spared organs at risk (OARs) better than the OTV‐based method while maintaining target coverage and improving the robustness of targets and OARs. Compared with composite and voxel‐wise worst case optimization, the all‐scenario robust optimization converged faster, and arrived at solutions of tighter DVH robustness spread, better target coverage and lower OAR dose.

Conclusion

An all‐scenario robust IMPT treatment planning system was developed using an adaptive quasi‐Newton optimization method. The optimization system was GPU‐accelerated and based on MC dose calculation. Improved performance was observed in clinical cases when compared with worst case optimization methods.
Quantitative Analysis of Surface Electromyography for Pediatric Neuromuscular Disorders
Authors: Higashihara Mana , Sonoo Masahiro , Ishiyama Akihiko , Nagashima Yu , Matsumoto Kohji , Uesugi Haruo , Mori‐Yoshimura Madoka , Murata Miho , Murayama Shigeo , Komaki Hirofumi
Published: July 2018

Introduction: Needle electromyography (EMG) has been an important diagnostic tool, although discomfort may limit its use in some children. We investigated the diagnostic utility of the clustering index (CI) method, a quantitative analysis for surface EMG (SEMG), in children. Methods: SEMG was recorded from the tibialis anterior muscle. Discriminant analysis between patients with neurogenic disorders and patients with myopathy was performed for whole epochs by using the CI and area values. Results: Forty‐five children (29 with myopathy, 16 with neurogenic disorders; age 9 ± 3.9 years) were enrolled. The mean discriminant function value of the neurogenic group was 0.58 ± 0.88 (−0.48–2.30), whereas that of the myopathic group was −0.55 ± 0.70 (−2.38–0.68). When the cutoff value was set at the limit of the other group, 17 of 29 children with myopathy and 7 of 16 children with neurogenic disorders were correctly classified. Discussion: The CI method can be a useful noninvasive diagnostic tool in children with neuromuscular disorders. Muscle Nerve 58:824–827, 2018
Successful Synthesis of Gold Nanoparticles through Ultrasonic Spray Pyrolysis from a Gold(III) Nitrate Precursor and Their Interaction with a High Electron Beam
Authors: Shariq Mohammed , Friedrich Bernd , Budic Bojan , Hodnik Nejc , Ruiz‐Zepeda Francisco , Majerič Peter , Rudolf Rebeka
Published: July 2018

Herein, we report for the first time the successful preparation of a gold(III) nitrate [Au(NO3)3] water‐based precursor for use in a bottom‐up ultrasonic spray pyrolysis (USP) process. Due to its limited solubility in water, the precursor was prepared under reflux conditions with nitric acid (HNO3) as the solvent and ammonium hydroxide (NH4OH) as a neutralizer. This precursor enabled the USP synthesis of gold nanoparticles (AuNPs) and the in situ formation of low concentrations of NO2− and NO3− ions, which were caught directly in deionized water in a collection system. These ions were proven to act as stabilizers for the AuNPs. Investigations showed that the AuNPs were monodispersed and spherically shaped with a size distribution over three groups: the first contained 5.3 % AuNPs with diameters (2 r) <15 nm, the second contained 82.5 % AuNPs with 2 r between 15 and 200 nm, and the third contained 12.2 % AuNPs with 2 r>200 nm. UV/Vis spectroscopy revealed the maximum absorbance band of the AuNPs at λ=528 nm. Additionally, scanning transmission electron microscopy (STEM) observations of the smallest AuNPs (2 r<5 nm) revealed atomically resolved coalescence phenomena induced by interaction with the electron beam. Four stages of the particle‐growth process were distinguished: 1) movement and rotation of the AuNPs; 2) necking mechanism; 3) orientated attachment at matching facets; 4) reshaping of the AuNPs by surface diffusion. This provided important insight into the formation/synthesis process of the AuNPs.
Profiling of Hura crepitans L. latex by ultra‐high‐performance liquid chromatography/atmospheric pressure chemical ionisation linear ion trap Orbitrap mass spectrometry
Authors: Trinel Manon , Jullian Valérie , Le Lamer Anne‐Cécile , Mhamdi Icram , Mejia Kember , Castillo Denis , Cabanillas Billy Joel , Fabre Nicolas
Published: July 2018

Introduction

The phytochemistry of the latex of Hura crepitans L. (Euphorbiaceae), a widespread tree in the Amazonian forest having many uses, is little known. Only huratoxin, a daphnane diterpene orthoester, has been described despite the high pharmacological potential of this kind of compounds. Glucosphingolipids (cerebrosides) are also known to be distributed in Euphorbiaceae latexes.

Objective

To tentatively identify daphnanes diterpenes and cerebrosides in the latex of H. crepitans.

Methods

An ethanolic extract of the lyophilised latex of H. crepitans was analysed by ultra‐high‐performance liquid chromatography (UHPLC) coupled with positive and negative atmospheric pressure chemical ionisation high‐resolution mass spectrometry (APCI‐HRMS) method using a quadrupole/linear ion trap/Orbitrap (LTQ‐Orbitrap). Tandem mass spectrometry (MS/MS) spectra were recorded by two different fragmentation modes: collision induced dissociation (CID) and higher‐energy collisional dissociation (HCD).

Results

The analysis of CID‐ and HCD‐MS/MS spectra allowed to propose fragmentation patterns for daphnane esters and cerebrosides and highlight diagnostic ions in positive and negative ion modes. A total of 34 compounds including 24 daphnane esters and 10 cerebrosides have been tentatively annotated. Among them, 17 daphnane diterpenes bearing one or two acyl chains are new compounds and the cerebrosides are described in the genus Hura for the first time.

Conclusion

This study revealed the chemical constituents of the latex of H. crepitans and particularly its richness and chemical diversity in daphnane diterpenes, more frequently encountered in the species of Thymelaeaceae.
Engineering of Al/CuO Reactive Multilayer Thin Films for Tunable Initiation and Actuation
Authors: Rossi Carole
Published: July 2018

Sputter‐deposited Al/CuO multilayers represent the state‐of‐the‐art of energetic nanomaterials for tunable ignition and actuation because their theoretical energy densities are significantly higher than most conventional secondary explosives while being less sensitive to undesired initiation. Both the sensitivity and combustion properties (temperature, combustion velocity and products of reaction) can be manipulated via the layering, reactant spacing and stoichiometry of the multilayer and, to a lesser extent, via interface engineering. In this article, we first describe the technology of deposition of Al/CuO multilayers focusing on direct current sputter deposition followed by a comprehensive review of the materials structural characteristics. Next, experimental and theoretical works performed on these reactive multilayered materials to date is presented in terms of methods used, the results acquired on ignition and combustion properties, and conclusions drawn. Emphasis is placed on several studies elucidating the fundamental processes that underlie propagating combustion reactions. This paper provides a good support for engineers to safely propose Al/CuO multilayers structure to regulate the energy release rates and ignition threshold in order to manufacture high performance and tunable initiator devices.
Groove Charge of a Rigid Multi‐Point Initiation Explosive Network
Authors: Li Rui , Li Wei‐bing , Guo Xiao‐de , Liang Li , Li Wen‐bin , Wang Xiao‐ming , Zhu Jian‐jun
Published: July 2018

To improve the groove charge density and reduce the initiation synchronicity error of a multi‐point initiation explosive network, CL‐20/NC and HMX/NC polymer‐bonded explosives (PBXs) with 95 wt.% ultrafine CL‐20 or ultrafine HMX as main explosive, with 5 wt.% NC as binder, were prepared. The morphology and crystal of the two PBXs was characterized in scanning electron microscopy, X‐ray diffractometry, and Fourier‐transform infrared spectroscopy. The critical dimension for linear detonation is 0.9 mm for the CL‐20/NC PBX and 1.5 mm for the HMX/NC PBX, and with the detonation velocity of the former being 36.2 % higher than the latter. Hence, the CL‐20/NC PBX was selected as groove charge for the multi‐point initiation explosive network. An explosive network charging method is proposed that involves groove press‐loading charging with three pre‐pressed booster pellets as output end charges. This configuration increases the density of the booster charge in the grooves to 1.880 g ⋅ cm−3 (94 % of theoretical density), effectively improving the charging density consistency and lowering the network initiation synchronicity error to less than 100 ns. The rod‐shaped explosively formed projectile has a small lateral offset and good shape indicating that the synchronization of the optimized explosive network meets the requirement of a selectable shaped charge projectile.
Adaptive unit vector control of multivariable systems using monitoring functions
Authors: Hsu Liu , Oliveira Tiago Roux , Cunha José Paulo V. S. , Yan Lin
Published: July 2018

An adaptive sliding‐mode unit vector control approach based on monitoring functions to deal with disturbances of unknown bounds is proposed. An uncertain multivariable linear system is considered with a quite general class of nonsmooth disturbances. Global stabilization/tracking is demonstrated using either state or output feedback. The proposed adaptation method makes the control gain less conservative, becoming large enough when the disturbance grows and becoming smaller when it decreases, leading to reduced chattering effects. In contrast to previous methods, the new switching scheme is able to guarantee a prespecified transient time, maximum overshoot, and steady‐state error for multivariable uncertain plants. The proposed technique is applied to the trajectory tracking control of a surface vessel subjected to ocean currents, wind, and waves. Simulations are presented to show the performance of the new adaptation scheme in this adverse scenario of possibly growing, temporarily large, or vanishing exogenous disturbances.
Practical and statistical challenges in driving research
Authors: Dawson Jeffrey D.
Published: July 2018

Driving is an integral aspect of many modern societies, and motor vehicle safety is an important public health issue. With advances in sensor technology, more and more driving data are being collected by researchers, insurers, and automobile companies, which has increased the need and opportunities for statisticians to be involved in driving research. This report discusses several practical and statistical challenges in driver‐level studies, including the process of defining meaningful driving metrics, issues related to “Big Data” aspects of driving research, and the principle of reproducible research.
Quantifying and presenting overall evidence in network meta‐analysis
Authors: Lin Lifeng
Published: July 2018

Network meta‐analysis (NMA) has become an increasingly used tool to compare multiple treatments simultaneously by synthesizing direct and indirect evidence in clinical research. However, many existing studies did not properly report the evidence of treatment comparisons and show the comparison structure to audience. In addition, nearly all treatment networks presented only direct evidence, not overall evidence that can reflect the benefit of performing NMAs. This article classifies treatment networks into three types under different assumptions; they include networks with each treatment comparison's edge width proportional to the corresponding number of studies, sample size, and precision. In addition, three new measures (ie, the effective number of studies, the effective sample size, and the effective precision) are proposed to preliminarily quantify overall evidence gained in NMAs. They permit audience to intuitively evaluate the benefit of performing NMAs, compared with pairwise meta‐analyses based on only direct evidence. We use four case studies, including one illustrative example, to demonstrate their derivations and interpretations. Treatment networks may look fairly differently when different measures are used to present the evidence. The proposed measures provide clear information about overall evidence of all treatment comparisons, and they also imply the additional number of studies, sample size, and precision obtained from indirect evidence. Some comparisons may benefit little from NMAs. Researchers are encouraged to present overall evidence of all treatment comparisons, so that audience can preliminarily evaluate the quality of NMAs.
Cysteine‐metal Porous Frameworks as Biosensing Elements for the Adsorption of Reactive Oxygen Species
Authors: Jena N. R. , Patel C. , Sahoo Subash Ch. , Mishra P. C.
Published: July 2018

The involvements of in vivo reactive oxygen species, such as superoxide radical (O2.−), peroxynitrite (ONOO−), hydrogen peroxide (H2O2), hydroxyl radical (.OH), peroxyl radical (.OOH), nitrogen oxide radical (NO.), etc in cancer and other diseases are well documented. However, the availability of biosensing elements to detect the presence of reactive oxygen species inside living cells is rare. Herein, B3LYP−D3 dispersion‐corrected density functional theory has been used to design different porous frameworks by coordinating several divalent transition metals, such as Mn+2, Fe+2, Co+2, Cu+2, and Zn+2 with cysteine (Cys) that can detect the presence of various reactive oxygen species. It is found that among all the metals, Cu+2 has the strongest interaction with Cys, thereby producing several stable porous frameworks. Among these frameworks, [Cys‐Cu+2]3(8‐1) is found to possess the largest pore and can adsorb both the anionic (O2.−, ONOO.−) and neutral reactive oxygen species (.OH, .OOH, and NO.) in the aqueous environment. It is thus proposed that the elongation of [Cys‐Cu+2]3(8‐1) framework can generate a novel biosensing element, which can be used for the sensing of various reactive oxygen species. However, experimental verification of the proposed material is required to confirm its applicability.
Microwave‐Assisted Synthesis of a Polypyrrole/Graphene Composite Using a Pyrrole‐Induced Graphene Oxide Hydrogel for the Selective Determination of Dihydroxybenzenes
Authors: Qi Yunlong , Cao Yue , Meng Xiaotong , Yu Kecheng , Si Weimeng , Lei Wu , Hao Qingli , Li Jiao , Wang Fagang
Published: July 2018

Pyrrole was utilized to induce the cross‐link of graphene oxide, resulting in a stable hydrogel. Following, polypyrrole/graphene composite was prepared using direct microwave treatment of this pyrrole‐induced hydrogel. Where, graphene oxide was chemically reduced and pyrrole in the composite was polymerized. The polypyrrole was homogeneously distributed throughout the graphene sheets. The as‐synthesized composite had a three‐dimensional, cross‐linked structure with advanced electro‐catalytic properties for hydroquinone and catechol. This feature was demonstrated by the superior electrochemical reversibility and good peak separation exhibited by the novel composite material. Accordingly, the detection of the two dihydroxybenzenes using this material produced a detection limit of 0.88 μM for hydroquinone and 0.69 μM for the catechol.
Morphology, Structure Evolution and Site‐Selective Occupancy of Eu3+ in Ca10(PO4)6(OH)2 Nanorods Synthesized via Subcritical Hydrothermal Method
Authors: Zhang Yan , Duan Mengna , Yan Jiaqing , Wang Shan , Yuan Long , Zhou Yanmin
Published: July 2018

The structure and composition evolution of hydroxyapatite in bone and teeth play important roles on their strength and durability, especially of the local chemical environment of Ca evolution, that determines bone demineralization and osteoporosis. In this paper, we synthesized a series of Eu‐doped (2‐10%) hydroxyapatite nanorod via subcritical hydrothermal method at high temperature (220‐280 oC) with the doped ions fully occupied at Ca1‐site. The as‐synthesized samples are grown with uniform particle size and shape distribution. Crystal morphology formation mechanism has been discussed based on the Bravais–Friedel–Donnay–Harker method and crystal structure of hydroxyapatite. Powder X‐ray diffraction result and Pawley fitting of the diffraction pattern for Eu‐doped hydroxyapatite samples indicate a linear structure evolution with increasing doping level. FTIR spectra suggest the minimal structure change for Eu‐doped hydroxyapatite nanocrystals. Photoluminescent spectra of Ca10(PO4)6(OH)2:Eu indicates the doping of Eu happens at the Ca1‐site, which shows a concentration‐dependent emission intensity evolution behavior. Decay curves for the 5D0→7F2 transition of Eu3+ in each samples suggested a longer lifetime in our samples than the similar composition that prepared via other methods. The site‐selective occupancy of Eu‐doped hydroxyapatite luminescent phenomenon may serve as a potential indicator for monitoring the Ca‐loss in bones and teeth that caused osteoporosis in aging people.
Silver Nanowire Templating Synthesis of Mesoporous SnO2 Nanotubes: An Effective Gas Sensor for Methanol with a Rapid Response and Recovery
Authors: Liu Huali , Wei Dongdong , Yan Yan , Li Ang , Chuai Xiaohong , Lu Geyu , Wang Yu
Published: July 2018

A novel mesoporous SnO2 nanotube with uniform morphology can be synthesized by using Ag nanowire as a sacrificial template and Tin‐alginate as Sn source via a self‐assembly process. The void of mesoporous SnO2 nanotubes can be precisely controlled by tuning the coating thicknesses of Tin‐alginate (TA) in Ag@TA core‐shell nanocables. In‐situ variable temperature X‐ray spectrum shows that the evolution process of mesoporous SnO2 nanotubes is driven by the minimization of free energy. In contrast to general SnO2 nanostructures, the mesoporous SnO2 nanotubes exhibit efficacious methanol sensing behaviors. The dynamic transients reveal their significantly enhanced gas response of 1.88 to 1 ppm methanol with rapid response and recovery times of 3 and 6 s, respectively. This simple strategy provides new insights to design and synthesize other inorganic metal oxide nanoarchitectures by using different templates and metal ions.
Elevated slabs made of hybrid reinforced concrete: Proposal of a new design approach in flexure
Authors: Facconi Luca , Plizzari Giovanni , Minelli Fausto
Published: July 2018

When designing fiber‐reinforced concrete (FRC) structures, one of the basic design issues is represented by the choice of a proper combination of fibers and conventional reinforcement that allows to obtain the best structural performance with the minimum amount of materials. The combination of rebars and fibers in the concrete matrix is generally known as Hybrid Reinforced Concrete (HRC). HRC represents a feasible solution in many structures; among these, slabs are gaining an increasing interest among practitioners. In fact, slabs are the most widespread structural elements in common practice as they are typically used to construct slabs on ground (industrial floors or foundations), slabs on piles (foundations) or elevated slabs. This paper focuses on the flexural design of FRC elevated slabs by using the most recent design provisions reported in the fib Model Code 2010. A simplified design procedure based on a consolidated design practice is proposed. Emphasis is given to the use of HRC to minimize the total reinforcement (fibers + rebars) in order to get practical and economic advantages during construction (ie, construction time and costs reduction). In more detail, a procedure for proportioning the hybrid reinforcement and then verifying the structural safety will be presented and discussed. Numerical nonlinear finite element analyses will be carried out to assess the effectiveness of the proposed design method.
Estimates of the prevalence, incidence and severity of dementia in Ireland
Authors: Pierse T. , O’ Shea E. , Carney P.
Published: July 2018

Objectives

In this paper we provide revised estimates of the prevalence of dementia in Ireland, the number of new cases per year and the severity mix. These estimates are a necessary input for any assessment of the potential demand for services and supports for people with dementia across all care settings in Ireland.

Methods

The prevalence, incidence and severity stage of dementia are calculated by applying rates from prominent international studies to population data from the 2016 census.

Results

We show that the total number of people with dementia in Ireland ranges between 39 272 and 55 266, depending on the international rates used to measure prevalence. The incidence of dementia in Ireland has increased as the population has aged, to at least 7752 new cases per year. We estimate that there are at least 11 175 people living at home in the community in Ireland with dementia who have a serious functional impairment, based on an Activities of Daily Living measurement, of which an estimated 1876 are chair or bedbound.

Conclusions

Without a national prevalence study it is not possible to be precise about the estimates of the number of people with dementia in Ireland. However, having credible upper and lower bound estimates for the number of people with dementia, the potential number of new cases per year and severity rates is useful for planners and those charged with the responsibility of making resource allocation decisions in dementia.
AGENTS, PRINCIPALS, OR SOMETHING IN BETWEEN? BUREAUCRATS AND POLICY CONTROL IN THAILAND
Authors: Ricks Jacob I.
Published: July 2018

In the aftermath of the 2006 and 2014 Thai coups, observers declared the resurrection of the bureaucratic polity. Bureaucrats, though, remained influential even during the period of 1992–2006, when elected politicians were thought to command the Thai state. Bureaucratic involvement in politics poses a challenge for dominant political science theories of politician–bureaucrat relationships, which draw heavily from principal–agent frameworks. I apply agency theory to Thailand, testing three different hypotheses derived from the theory. Examining legislative productivity and control over bureaucratic career trajectories, I find that elected politicians increasingly acted as principals of the Thai state from 1992 through 2006, and to a lesser degree from 2008 to 2013. Thai bureaucrats, though, have frequently engaged in the political sphere, blunting political oversight and expanding their independence vis-à-vis politicians. This suggests that the principal–agent model overlooks the range of resources that bureaucracies can bring to bear in developing countries, granting them greater autonomy than anticipated. As such, theories of the politician–bureaucrat relationship in developing states need to better account for the mechanisms through which bureaucrats exercise policy discretion and political influence.
THE DILEMMA OF CRITICISM: DISENTANGLING THE
DETERMINANTS OF MEDIA CENSORSHIP IN
CHINA
Authors: Shao Li
Published: July 2018

Recent literature claims that China censors information
that has the potential to ignite collective action.
This article extends this finding by arguing that
Chinese censors respond differently to political
challenges than they do to performance challenges.
Political challenges call into questioning the
Party's leading role, whereas performance challenges
are directed at the failures of public goods
provisions. A survey experiment of about 60 media
professionals finds that censors are inclined to
block political challenges and to tolerate criticism
of the government's performance. However, when
criticism contains both performance and political
challenges, censorship is far more likely. By
exploring the range of censorship activities, the
results suggest that the Chinese regime's reliance
on popular support constrains its censorship
decisions.
Increasing contribution of grain boundary compliance to polycrystalline ice elasticity as temperature increases
Authors: SAYERS COLIN M.
Published: July 2018

Measured elastic stiffnesses of ice polycrystals decrease with increasing temperature due to a decrease in grain boundary stiffness with increasing temperature. In this paper, we represent grain boundaries as imperfectly bonded interfaces, across which traction is continuous, but displacement may be discontinuous. We express the additional compliance due to grain boundaries in terms of a second-rank and a fourth-rank tensor, which quantify the effect on elastic wave velocities of the orientation distribution as well as the normal and shear compliances of the grain boundaries. Measurement of the elastic stiffnesses allows determination of the components of these tensors. Application of the method to resonant ultrasound spectroscopy measurements made on ice polycrystals enables determination of the ratio BN/BS of the normal to shear compliance of the grain boundaries, which are found to be more compliant in shear than in compression. The ratio BN/BS is small at low temperatures, but increases as temperature increases, implying that the normal compliance increases relative to the shear compliance as temperature increases.
ON BASE RADICAL OPERATORS FOR CLASSES OF FINITE ASSOCIATIVE RINGS
Authors: MCDOUGALL R. G. , THORNTON L. K.
Published: July 2018

In this paper, class operators are used to give a complete listing of distinct base radical and semisimple classes for universal classes of finite associative rings. General relations between operators reveal that the maximum order of the semigroup formed is 46. In this setting, the homomorphically closed semisimple classes are precisely the hereditary radical classes and hence radical–semisimple classes, and the largest homomorphically closed subclass of a semisimple class is a radical–semisimple class.
A GENERAL POSITION PROBLEM IN GRAPH THEORY
Authors: MANUEL PAUL , KLAVŽAR SANDI
Published: July 2018

The paper introduces a graph theory variation of the general position problem: given a graph $G$, determine a largest set $S$ of vertices of $G$ such that no three vertices of $S$ lie on a common geodesic. Such a set is a max-gp-set of $G$ and its size is the gp-number $\text{gp}(G)$ of $G$. Upper bounds on $\text{gp}(G)$ in terms of different isometric covers are given and used to determine the gp-number of several classes of graphs. Connections between general position sets and packings are investigated and used to give lower bounds on the gp-number. It is also proved that the general position problem is NP-complete.
ALGEBRAIC NUMBERS WITH BOUNDED DEGREE AND WEIL HEIGHT
Authors: DUBICKAS ARTŪRAS
Published: July 2018

For a positive integer$d$and a nonnegative number$\unicode[STIX]{x1D709}$, let$N(d,\unicode[STIX]{x1D709})$be the number of$\unicode[STIX]{x1D6FC}\in \overline{\mathbb{Q}}$of degree at most$d$and Weil height at most$\unicode[STIX]{x1D709}$. We prove upper and lower bounds on$N(d,\unicode[STIX]{x1D709})$. For each fixed$\unicode[STIX]{x1D709}>0$, these imply the asymptotic formula$\log N(d,\unicode[STIX]{x1D709})\sim \unicode[STIX]{x1D709}d^{2}$as$d\rightarrow \infty$, which was conjectured in a question at Mathoverflow [https://mathoverflow.net/questions/177206/].
Bishop Bartholomew of Exeter (d. 1184) and the Heresy of Astrology
Authors: RUNCIMAN DAVID
Published: July 2018

In the late twelfth century, Bartholomew, bishop of Exeter (1161–84), identified astrology as the most serious heresy facing the English Church. The evidence of Bartholomew's writing suggests that astrology became more widely accepted among the English clergy during his episcopal tenure. It also supports the view that popular heretical movements enjoyed little success in England during this period, in contrast to some regions in mainland Europe. Instead, it was scholars deemed guilty of intellectual error, and above all the astrologers, who became the focus of Bartholomew's anxieties about heresy and the intellectual culture of his day.
Is the use of a bone conduction hearing device on a softband a useful tool in the pre-operative assessment of suitability for other hearing implants?
Authors: Spielmann P M , Roplekar R , Rae C , Ahmed F , Jones S E M
Published: July 2018

Objective

To assess whether pre-operative assessment with a bone conduction hearing device on a softband is an accurate predictor of performance with one of two transcutaneous hearing implants.

Study design

Cohort study comparing pre-and post-operative speech audiometry using correlation analysis.

Methods

Pre-operative pure tone audiometry and aided half optimum speech recognition thresholds were compared with post-operative aided results for each ear that had undergone implantation. Data were collected prospectively.

Results

Full data were available in 24 ears. In 19 out of 24 ears (79 per cent), the difference between pre- and post-operative speech scores was less than 10 dB, demonstrating a good clinical correlation. The Pearson correlation coefficient was calculated at 0.66 (95 per cent confidence interval = 0.357–0.842), indicating a strong statistical correlation.

Conclusion

Pre-operative softband testing shows good clinical correlation and strong statistical correlation with hearing implant performance. The findings suggest there is value in using the test to predict performance and guide patients’ expectations.