bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydrogen/deuterium exchange mass spectrometry in the world of small molecules
Authors: Damont Annelaure , Legrand Anaïs , Cao Chenqin , Fenaille François , Tabet Jean‐Claude
Published: December 2021

The combined use of hydrogen/deuterium exchange (HDX) and mass spectrometry (MS), referred to as HDX‐MS, is a powerful tool for exploring molecular edifices and has been used for over 60 years. Initially for structural and mechanistic investigation of low‐molecular weight organic compounds, then to study protein structure and dynamics, then, the craze to study small molecules by HDX‐MS accelerated and has not stopped yet. The purpose of this review is to present its different facets with particular emphasis on recent developments and applications. Reversible H/D exchanges of mobilizable protons as well as stable exchanges of non‐labile hydrogen are considered whether they are taking place in solution or in the gas phase, or enzymatically in a biological media. Some fundamental principles are restated, especially for gas‐phase processes, and an overview of recent applications, ranging from identification to quantification through the study of metabolic pathways, is given.
Cyclicality of capital adequacy ratios in heterogeneous environment: A nonlinear panel smooth transition regression explanation
Authors: Rubbaniy Ghulame , Khalid Ali Awais , Polyzos Stathis , Almessabi Balqees Naser
Published: December 2021

Our study uses a new business cycle (BC) index and a nonlinear panel smooth transition regression model on quarterly data of 1538 bank holding companies of the United States to investigate response of capital adequacy ratios (CARs) to changes in economic activity. Our findings confirm the existence of nonlinear effects of BC on CARs. Although we use a nonlinear model and a new proxy of BC, our results about CARs are not only consistent with existing mainstream literature but also improve estimation and goodness of the estimation of CARs. The study outcome is useful for policymakers for CARs' standards adjustments during recessions.
Strategic commitments of downstream investment firms
Authors: Lee DongJoon , Oh Joonghwa
Published: December 2021

This study investigates the strategic commitment of downstream firms' private R&D investments. While an observable investment, as a pre‐production commitment, influences an upstream firm's input price, it affects a rival downstream firm's output. We show that both downstream firms commit to underinvestment (overinvestment) to reduce an input price (compete with a rival firm) in cases of small (large) product substitutability. However, they make their aggressive investments unobservable in the market in cases of medium product substitutability. Furthermore, when both products are sufficiently differentiated, consumer surplus and social welfare are larger when downstream investments are unobservable.
NAMI Maryland giving back via ‘Giving Tuesday’ campaign
Authors: Canady Valerie A.
Published: December 2021

Last week, mental health groups embarked on their annual donation campaigns, noted as “Giving Tuesday,” representing the first Tuesday in December and considered a global day of giving to raise money to support individuals and families with mental health needs.
A W‐band sparse phased array antenna withultrahighsparsity for radar applications
Authors: Xiao Runjun , Shi Yu , Ding Zhuofu , Tang Ming‐Chun
Published: December 2021

A sparse phased array with 4% sparsity is developed for advanced low‐cost W‐band radar applications. A high‐order radiation mode‐based substrate‐integrated waveguide antenna featuring waveguide feeding is employed as the antenna element to achieve feeding loss reduction and antenna gain enhancement. An improved optimization technique is adopted to optimize the antenna element distribution. The combination of the element distribution and the antenna element radiation pattern achieves grating lobe suppression. Both the simulation and measurement results show that a ±15° beam scanning range can be achieved, and the level of the measured normal and scanning sidelobes is lower than −18 dB and −13 dB, respectively.
Design of novel compact SISL filters with multiple TZs based on patch resonators
Authors: Gao Wei , Ma Kaixue , Wang Yongqiang , Xu Wei
Published: December 2021

This letter presents two compact filters using patch resonators based on the substrate integrated suspended line (SISL) technology platform. First, a bandpass filter (BPF) with multiple coupling schemes is designed by using a shorted‐stub‐loaded patch resonator. Two shorted stepped‐impedance resonators are working together to form the third‐order BPF. A 98.18% size reduction is achieved, and five transmission zeros (TZs) are produced by introduced mixed electric and magnetic coupling, cross‐coupling, and source to load coupling. Then, the SISL dual‐band bandpass filter (DBBPF) with six TZs is designed by using an improved slotted patch resonator. By adopting the patterned suspended substrate structure, the implemented DBBPF, featured with self‐packaging, achieves a fractional bandwidth of 52% and 10%, centered at 0.95 and 3.25 GHz with insertion losses of 0.57 and 2.89 dB, respectively.
Improving the classification ability of network utilizing fusion technique in contrast‐enhanced spectral mammography
Authors: Song Jingqi , Zheng Yuanjie , Xu Chenxi , Zou Zhenxing , Ding Guocheng , Huang Wenhui
Published: December 2021

Purpose

Contrast‐enhanced spectral mammography (CESM) is an effective tool for diagnosing breast cancer with the benefit of its multiple types of images. However, few models simultaneously utilize this feature in deep learning‐based breast cancer classification methods. To combine multiple features of CESM and thus aid physicians in making accurate diagnoses, we propose a hybrid approach by taking advantages of both fusion and classification models.

Methods

We evaluated the proposed method on a CESM dataset obtained from 95 patients between ages ranging from 21 to 74 years, with a total of 760 images. The framework consists of two main parts: a generative adversarial network based image fusion module and a Res2Net‐based classification module. The aim of the fusion module is to generate a fused image that combines the characteristics of dual‐energy subtracted (DES) and low‐energy (LE) images, and the classification module is developed to classify the fused image into benign or malignant.

Results

Based on the experimental results, the fused images contained complementary information of the images of both types (DES and LE), whereas the model for classification achieved accurate classification results. In terms of qualitative indicators, the entropy of the fused images was 2.63, and the classification model achieved an accuracy of 94.784%, precision of 95.016%, recall of 95.912%, specificity of 0.945, F1_score of 0.955, and area under curve of 0.947 on the test dataset, respectively.

Conclusions

We conducted extensive comparative experiments and analyses on our in‐house dataset, and demonstrated that our method produces promising results in the fusion of CESM images and is more accurate than the state‐of‐the‐art methods in classification of fused CESM.
Interpretation of EPR and optical spectra of Ni(II) ions in crystalline lattices at ambient temperature
Authors: Amrutha Kamalon , Kathirvelu Velavan
Published: December 2021

Many biologically important paramagnetic metal ions are characterized by electron paramagnetic resonance (EPR) spectroscopy to use as spin probes to investigate the structure and function of biomolecules. Though nickel(II) ions are an essential trace element and part of many biomolecules, the EPR properties are least understood. Herein, the EPR and optical absorption spectra measured at 300 K for Ni(II) ions diluted in two different diamagnetic hosts are investigated and reported. The EPR spectrum of a polycrystalline Ni/Mg(3‐methylpyrazole)6(ClO4)2 [Ni/MMPC] shows two transitions at X‐band frequency (~9.5 GHz), suggesting the zero‐field splitting parameter (D) is larger than the resonance field of the free electron (Ho). This incomplete and complex spectrum is successfully analyzed to obtain EPR parameters. The EPR spectrum of the polycrystalline Ni/Zn(pyrazole)6(NO3)2 [Ni/ZPN] shows a triplet spectrum indicating D < Ho. A detailed analysis of single‐crystal EPR data yielded the spin Hamiltonian parameters. The optical absorption spectra are deconvoluted to understand the symmetry of the coordination environment in the complex.
3D asymmetric expectation‐maximization attention network for brain tumor segmentation
Authors: Zhang Jianxin , Jiang Zongkang , Liu Dongwei , Sun Qiule , Hou Yaqing , Liu Bin
Published: December 2021

Automatic brain tumor segmentation on MRI is a prerequisite to provide a quantitative and intuitive assistance for clinical diagnosis and treatment. Meanwhile, 3D deep neural network related brain tumor segmentation models have demonstrated considerable accuracy improvement over corresponding 2D methodologies. However, 3D brain tumor segmentation models generally suffer from high computation cost. Motivated by a recently proposed 3D dilated multi‐fiber network (DMF‐Net) architecture that pays more attention to reduction of computation cost, we present in this work a novel encoder‐decoder neural network, ie a 3D asymmetric expectation‐maximization attention network (AEMA‐Net), to automatically segment brain tumors. We modify DMF‐Net by introducing an asymmetric convolution block into a multi‐fiber unit and a dilated multi‐fiber unit to capture more powerful deep features for the brain tumor segmentation. In addition, AEMA‐Net further incorporates an expectation‐maximization attention (EMA) module into the DMF‐Net by embedding the EMA block in the third stage of skip connection, which focuses on capturing the long‐range dependence of context. We extensively evaluate AEMA‐Net on three MRI brain tumor segmentation benchmarks of BraTS 2018, 2019 and 2020 datasets. Experimental results demonstrate that AEMA‐Net outperforms both 3D U‐Net and DMF‐Net, and it achieves competitive performance compared with the state‐of‐the‐art brain tumor segmentation methods.
A gamified mobile health intervention for children in day surgery care: Protocol for a randomized controlled trial
Authors: Rantala Arja , Vuorinen Anna‐Leena , Koivisto Jonna , Similä Heidi , Helve Otto , Lahdenne Pekka , Pikkarainen Minna , Haljas Kadri , Pölkki Tarja
Published: December 2021

Aims

To describe a study protocol for a randomized controlled trial which will evaluate the effectiveness of a gamified mobile health intervention for children in whole day surgery care.

Design

A study protocol for a two‐arm randomized controlled trial.

Methods

Participants will be randomly assigned to the intervention group (N = 62), in which patients receive routine care and play a mobile game designed for children or the control group (N = 62), in which patients receive routine care, including a mobile phone application that supports parents during the care path. The primary outcome is children's pre‐operative anxiety, while the secondary outcome measures included fear and postoperative pain, along with parental satisfaction and anxiety. Data collection started in August 2020.

Results

The results of the ongoing randomized controlled trial will determine whether the developed gamified mobile health intervention can be recommended for hospital use, and whether it could be used to educate children about their surgical treatment to decrease anxiety.
The detection and prevention of adverse drug events in nursing home and home care patients: Study protocol of a quasi‐experimental study
Authors: Langenberger Benedikt , Baier Natalie , Hanke Frank‐Christian , Fahrentholz Jacqueline , Gorny Christina , Sehlen Stephanie , Reber Katrin Christiane , Liersch Sebastian , Radomski Ralf , Haftenberger Jens , Heppner Hans Jürgen , Busse Reinhard , Vogt Verena
Published: December 2021

Aim

To estimate the cost‐effectiveness of an intervention facilitating the early detection of adverse drug events through the means of health professional training and the application of a digital screening tool.

Design

Multi‐centred non‐randomized controlled trial from August 2018 to March 2020 including 65 nursing homes or home care providers.

Methods

We aim to estimate the effect of the intervention on the rate of adverse drug events as primary outcome through a quasi‐experimental empirical study design. As secondary outcomes, we use hospital admissions and falls. All outcomes will be measured on patient‐month level. Once the causal effect of the intervention is estimated, cost‐effectiveness will be calculated. For cost‐effectiveness, we include all patient costs observed by the German statutory health insurance.

Results

The results of this study will inform about the cost‐effectiveness of the optimized drug supply intervention and provide evidence for potential reimbursement within the German statutory health insurance system.
Preparation of continuous glass fiber/polyamide 6 composites containing hexaphenoxycyclotriphosphazene: Mechanical properties, thermal stability, and flame retardancy
Authors: Yan Chun , Yan Pengwei , Xu Haibing , Liu Dong , Chen Gang , Cai Guangbin , Zhu Yingdan
Published: December 2021

The halogen‐free flame‐retardant continuous glass fiber/polyamide 6 (GF/PA6) composites containing hexaphenoxycyclotriphosphazene (HPCTP) were prepared by the resin transfer molding (RTM) process. The influence of HPCTP content on mechanical properties of GF/PA6 composites was studied. The addition of HPCTP has no obvious effect on the tensile properties of composites, and the tensile strength of GF/PA6 composites with the addition of 30% HPCTP reaches 425.2 MPa. However, with the addition of HPCTP, the flexural strength and interlaminar shear strength of GF/PA6/30%HPCTP composites decrease to 246.4 and 20.9 MPa, respectively. The flame retardancy, thermal stability, and burning behavior of the composites were evaluated by means of limited oxygen index (LOI), UL‐94, thermogravimetric analysis and cone calorimeter. The results show that the LOI value of GF/PA6 composites can reach up to 30.9% corresponding to the grade of UL‐94V‐0 with the addition of 30% HPCTP. The flame retardancy mechanism of GF/PA6/30%HPCTP composites is attributed to the combined effects of releasing incombustible gases in gas phase at the early stage and forming char layers in the condensed phase, which can dilute the concentration of combustible gas and retard the mass and heat transfer.
Eco‐friendly solution processing of all‐polymer solar cells: Recent advances and future perspective
Authors: Xiong Yuan , Ye Long , Zhang Chao
Published: December 2021

All‐polymer solar cells (all‐PSCs) exhibit great potentials in commercial applications. All‐PSCs have observed steady performance gains with power conversion efficiency now reaching over 17% in the open literature. However, the current processing of all‐PSCs relies predominantly on toxic, chlorinated solvents in moisture‐free environments, representing a significant barrier for their commercialization due to the added costs to handle and dispose of such solvents. There is thus an urgent need for safe, environmentally benign, and sustainable ink‐based processing methods to produce all‐PSC devices reliably and reproducibly in ambient air. In this perspective, fundamental insights on the interplay between all‐polymer blend morphologies and eco‐friendly solvents are provided. Also, we discuss the recent successes of the green processing methods to manipulate the photoactive morphologies for high‐efficiency all‐PSCs. In the end, we provide an outlook on future challenges and opportunities of eco‐friendly solvents processed all‐PSCs for large‐scale manufacturing.
Insecticide resistance in Drosophila melanogaster in vineyards and evaluation of alternative insecticides
Authors: Mertz Robert W , Hesler Stephen , Pfannenstiel Luke J , Norris Rachel H , Loeb Gregory , Scott Jeffrey G
Published: December 2021

BACKGROUND

Cultivation of grapes is a major crop globally, particularly in support of the wine production industry which has significant economic impact in numerous countries. Sour rot is an economically important disease of grapes. It is caused by an interaction of yeast + acetic acid bacteria, and vectored by Drosophila spp. Substantial control of sour rot in wine grape vineyards has been achieved by control of Drosophila using insecticides such as zeta‐cypermethrin. An outbreak of sour rot and high populations of Drosophila melanogaster were observed in 2018 in a vineyard in New York (Finger Lakes region), USA. Flies from this population were found to be resistant to zeta‐cypermethrin (the active ingredient in Mustang Maxx®), but whether or not this was a widespread problem was not known. To determine if resistance was geographically limited, we surveyed populations of D. melanogaster collected from 11 vineyards across New York State and one in Missouri (USA). We also evaluated 19 alternative insecticides for their potential use for control of D. melanogaster, by determining their toxicity to a susceptible strain and by examining cross‐resistance using a field‐collected population.

RESULTS

There were high levels of resistance to zeta‐cypermethrin, malathion, and acetamiprid found in all populations sampled. Resistance to zeta‐cypermethrin and malathion was stable over 33 months. Results from two vineyards also suggested that resistance to spinetoram was starting to evolve. The alternative insecticides we evaluated had LC50 values to the susceptible strain ranging from 0.65 to 15 000 ng·cm−2.

CONCLUSION

Resistance to zeta‐cypermethrin, malathion, and acetamiprid is geographically widespread and the levels of resistance are similar between early season and late season collections. Cross‐resistance was detected against all the insecticides tested, with the lowest levels seen for broflanilide, fipronil, and flumethrin. These patterns of resistance/cross‐resistance/multiple resistance are discussed in terms of selection within and outside of vineyards. The implications of these results to insecticide resistance monitoring and management are discussed.
Nano−Micro Characterization of Defects on Silicon Surfaces: An Industrial Perspective of Metrology Challenges
Authors: Borionetti Gabriella , Sanna Cristina
Published: December 2021

The electronic device industry is known to have been driven since its early stages by a continuous technological effort of miniaturization because of the dual need of manufacturing cost reduction through integration and offers to the user market of smaller electronic applications, more efficient, versatile, and differentiable. Silicon wafer manufacturers have been forced to provide larger size silicon wafers. 300 mm diameter is nowadays covering more than 50% of the total market, with dimension and density of residual defects moving from micrometers to nanometers, from ppt to ppq, or even less. In this context, the proper choice of measurement technique and setup which can guarantee measurement reliability to detect a given defect and provide information of its distribution inside the wafer is mandatory. It has to cope the need to control material quality in a range more frequently close to the measurement detection limit and improve the associated manufacturing process capabilities. Herein, a few examples in the area of crystallographic/morphological defects and chemical impurities on silicon wafers are proposed, reviewing the defect analysis approach inside a manufacturing environment. The discussion also involves the final product certification data reporting which tends to convey in a very synthetic format the whole measurement and control process.
Scutellarin ameliorates hepatic lipid accumulation by enhancing autophagy and suppressing IRE1α/XBP1 pathway
Authors: Zhang Xueying , Huo Zhaojiong , Luan Huiling , Huang Yihai , Shen Yanhui , Sheng Liang , Liang Jiangyu , Wu Feihua
Published: December 2021

Nonalcoholic fatty liver disease is the most prevalent liver disease characterized by excessive lipid accumulation in hepatocytes. Endoplasmic reticulum (ER) stress and autophagy play an important role in lipid accumulation. In this study, scutellarin (Scu) was examined in palmitic acid–treated HepG2 cells and C57/BL6 mice fed a high‐fat diet (HFD). Scu reduced intracellular lipid content and inhibited sterol regulatory element binding protein‐1c (SREBP‐1c)‐mediated lipid synthesis and fatty acid translocase‐mediated lipid uptake in HepG2 cells. Additionally, Scu restored impaired autophagy and inhibited excessive activation of ER stress in vivo and in vitro. Moreover, Scu upregulated forkhead box O transcription factor 1–mediated autophagy by inhibiting inositol‐requiring enzyme 1α (IRE1α)/X‐box‐binding protein 1 (XBP1) branch activation, while XBP1s overexpression exacerbated the lipid accumulation and impaired autophagy in HepG2 cells and also weakened the positive effects of Scu. Furthermore, Scu attenuated ER stress by activating autophagy, ultimately downregulating SREBP‐1c‐mediated lipid synthesis, and autophagy inhibitors offset these beneficial effects. Scu inhibited the crosstalk between autophagy and ER stress and downregulated saturated fatty acid–induced lipid accumulation in hepatocytes. These findings demonstrate that Scu ameliorates hepatic lipid accumulation by enhancing autophagy and suppressing ER stress via the IRE1α/XBP1 pathway.
A homogeneously weighted moving average control chart for monitoring time between events
Authors: Aslam Muhammad , Khan Majid , Anwar Syed Masroor , Zaman Babar
Published: December 2021

In high‐quality processes, non‐conforming events rarely occur, and the time between events (TBE) is more likely to follow a skewed distribution, such as gamma distribution. This paper proposes a gamma distribution‐based one‐sided homogeneously weighted moving average control chart for monitoring the TBE. The proposed control chart is known as the HWMA_TBE control chart. The HWMA_TBE control chart monitors the downward shifts in the process, that is, a decrease in inter‐arrival time that can lead to the process deterioration. The Monte Carlo simulation approach is used to compute specific performance indicators, such as average run length (), standard deviation run length , extra quadratic loss (), relative average run length (), and performance comparison index (). Based on these performance indicators, the HWMA_TBE control chart is compared to some competing control charts. The comparison suggests that the HWMA_TBE control chart is more efficient than the competing control charts. Moreover, this paper also investigates the robustness of the HWMA_TBE control chart, which indicates that the HWMA_TBE control chart is more robust than the competing control charts. In the end, two examples are provided, one with boring machine failure data and the other with breast cancer survival data, to evaluate the implementation of the HWMA_TBE control chart for practical situations.
Online monitoring of process variance drifts for leptokurtic and heavy‐tailed data
Authors: Tan Wushuang , Liu Liu
Published: December 2021

In many applications, monitoring the variance of a process online is very important. For example, in industrial and medical fields and weather and ocean research, monitoring the variance drift in processes can effectively reduce losses. This monitoring is especially important in finance because data tend to have leptokurtic and heavy‐tailed characteristics and there are few control charts for the online monitoring of variance drifts. Therefore, we develop a new exponentially weighted moving average control chart based on the sample quantiles of all pairwise differences: the EWMA control chart. This control chart shows a good performance in the online monitoring of variance drifts when the distribution is leptokurtic and heavy‐tailed, as is the case with the Student's t‐distribution, the Pareto distribution, and the generalized error distribution. To visually explain the EWMA control chart for monitoring the effect of variance drifts, we compare the monitoring efficiency of the EWMA control chart with that of two other control charts (the MDEWMA control chart and the GVA control chart) using Monte Carlo simulations and the RMI. The results show that the EWMA control chart is the most effective for monitoring the variance drifts of data with leptokurtic and heavy‐tailed distributions. Additionally, we use these three control charts to monitor the variance drifts of the weekly return rate of gold (data from Yahoo Finance) to illustrate the application of the EWMA control chart in practical cases.
On the positive stabilizability of sampled positive systems
Authors: Guo Baoyin , Zhang Liangyin , Chen Michael Z. Q. , Zou Yun
Published: December 2021

This paper investigates the problem of positive stabilizability of single‐input LTI positive systems. Firstly, for a single‐input continuous‐time positive linear system, it has been derived that a necessary condition of the existence of a stablilizing linear time‐invariant controller is the number of nonnegative real poles not being greater than one. Inspired by that, the continuous‐time positive stabilizability of systems with unstable complex poles is studied in this paper, where the third‐order and higher‐order cases are considered. Secondly, an enhanced method to construct the static state‐feedback gain of a sampled positive system is presented, which takes account of the positivity preservation in the sampling interval. According to the method, the positive stabilizablity of the single‐input second‐order sampled positive system is analyzed. Some numerical examples are finally presented to illustrate the theoretical results.
Distributed optimization with hybrid linear constraints for multi‐agent networks
Authors: Zheng Yanling , Liu Qingshan , Wang Miao
Published: December 2021

This article investigates the distributed constrained optimization with hybrid linear constraints for multi‐agent networks, in which all the agents collaboratively minimize the global objective function with a sum of convex local objective functions, while the constraints are more general with local and global restrictions on the agents. Based on matrix and graph theories, a discrete‐time algorithm under distributed manner is designed to deal with the organized problems. In addition, the optimality of the presented algorithm is obtained under certain initial restriction for the agents. By virtue of a novel Lyapunov function and the optimal conditions, rigorous analysis shows the convergence of the multi‐agent networks with undirected and connected graphs. Finally, two simulation examples are presented to validate the theoretical consequence.
Contract sex: Decriminalization versus legalization
Authors: Shrage Laurie
Published: December 2021

Why are sex worker rights groups advocating for decriminalizing sex work, but not for legalizing it? In this paper, I will explain why efforts to decriminalize sex work deserve the same support as efforts to decriminalize abortion, marijuana, or polygamy. Many human rights advocates now recognize that decriminalizing sexual transactions which take place among consenting adults in private, including informally contracting for sexual services, is necessary for protecting our fundamental human and civil rights. Yet decriminalizing individual acts of prostitution opens the door to various kinds of organized and public market activities, and there is little consensus among progressive reformers about how wide this door should be pushed opened. A consensus has been forming, nevertheless, among sex worker rights organizations. These groups generally hold that regulatory restrictions specific to sex work (“legalization”), which limit where and how contracting for sexual services can take place, leads to practices that are punitive toward sex workers in ways similar to criminalization. In this paper, I will consider the arguments for decriminalization and against legalization, and argue that accepting levels of governmental oversight above the norm may be a necessary compromise in order to change policies regarding a controversial activity.
Synthesis of 1‐(3‐(1‐substituted‐1,2,3‐triazol‐4‐yl)‐1,2,4‐triazol‐5‐yl)‐tetrazoles by Sequential Assembly of Azole Fragments
Authors: Zviagin Eugene , Saraev Vyacheslav , Sysoiev Dmytro , Klepetářová Blanka , Mazur Maryna , Zhelavskyi Oleksii , Shliapkina Yuliia , Müller Thomas J. J. , Chebanov Valentyn
Published: December 2021

Only few efficient methods for the preparation of polyazoles containing three or four nitrogen atoms in each azole cycle exist. We have developed a novel synthetic strategy that allows the sequential assembly of 1,2,3‐triazole, 1,2,4‐triazole, and tetrazole fragments into a new stable polyazole. Along the novel strategy, some known procedures have been optimized to achieve better conversion, selectivity, and, in general, overall efficiency.
Reactivity of 4‐pyrimidyl Sulfonic Esters in Suzuki‐Miyaura Cross‐Coupling Reactions in Water Under Microwave Irradiation
Authors: Vidal Matías , Rodríguez‐Aguilar José , Aburto Ignacio , Aliaga Carolina , Domínguez Moisés
Published: December 2021

The reactivity of four 4‐pyrimidyl sulfonic esters in Palladium‐catalyzed Suzuki–Miyaura cross‐coupling reactions was studied with various boronic acids. All the reactions were conducted in water under microwave irradiation. Electron‐rich aryl boronic acids exhibited higher yields when triflate (−OSO2CF3) was used as the pseudohalide, whereas electron‐poor aryl boronic acids reacted faster when nonaflate was employed (−OSO2(CF2)3CF3). Furthermore, the reactivity guide for Pd‐catalyzed coupling of these accessible pseudohalides with boron‐based coupling partners was applied to synthesize a bipyrimidine in excellent yield. Finally, the 2‐methylpyrimidines obtained are suitable starting materials for the synthesis of luminescent sensors.
Metal Organic Framework Derived Cu–Doped Ni2P Nanoparticles Incorporated with Porous Carbon as High Performance Electrocatalyst for Hydrogen Evolution Reaction in a Wide pH Range
Authors: Qu Bo , Wei Mengle , Lu Xuetao , Zhu Jinkun
Published: December 2021

The development of highly efficient and low cost electrocatalysts for hydrogen evolution reaction (HER) is crucial for electrochemical water splitting, which is considered as the most promising strategy to resolve the problems caused by the overexploit and consume of fossil fuel. Herein, we report the fabrication of copper nickel bimetallic phosphide nanoparticles encapsulated within hierarchical porous carbon (CuxNi1‐xP@PC) based on a bimetallic organic frameworks (BMOFs) assisted phosphorization route. The size‐controlled effect of BMOFs led to the ultrafine particle sizes (average about 10 nm), which possess large active surface area and high dispersity in the final catalyst materials. Remarkably, when investigated as electrocatalysts for HER, the fabricated CuxNi1‐xP@PC composites exhibited outstanding electrocatalytic activity and excellent long‐term stability toward HER at all pH values. It required overpotentials of 102 and 118 mV to reach a current density of 10 mA cm−2 in 0.5 M H2SO4 and 1.0 M KOH solution respectively, as well as Tafel slopes of 85.8 mV dec−1 and 73.1 mV dec−1. This work offers a promising route to explore BMOFs as precursor for the fabrication of hybrid electrocatalysts with high performance toward water splitting.
Aza‐Diels‐Alder Reaction of Danishefsky's Diene with Imine Catalyzed by N‐Heterocyclic Imidazole Halogen Bond Donors
Authors: Zhao Chang , Sun Cuihong , Li Xiaoyan , Zeng Yanli
Published: December 2021

Recently, the halogen bonding catalysis in Aza‐Diels‐Alder reaction is increasing gloriously. In this work, the mechanism of the Aza‐Diels‐Alder reaction between imine and Danishefsky's diene catalyzed by N‐heterocyclic imidazole halogen bond donors has been explored with density functional theory. It is revealed that the reaction has two possible pathways: [4+2] cycloaddition pathway and Mannich pathway, in agreement with experimental predictions. Formation of halogen bond between the iodine atom of the catalysts and the N atom of the imine, results in lower energy barriers and more favorable of the reaction. The catalytic effect of the halogen bond can result in the electron rearrangement, which facilitates the formation of C−C bond. The stronger electron‐withdrawing ability of the group bonded to iodine atom of catalysts is, the better the catalytic activity is. These findings could be helpful to develop halogen bond donor catalysts in organic reactions.
A Non‐Ionic Precursor for Preparing Di‐, Tetra‐, Hexanitro‐2,4,6,8,10,12‐hexaazatricyclo[7,3,0,03,7]dodecane‐5,11‐dione: Synthesis, Mechanism and Properties
Authors: Zhang Xiya , Lin Xiangyang , Huang Haifeng
Published: December 2021

A non‐ionic precursor 2,4,6,8,10,12‐hexaazatricyclo[7,3,0,03,7]dodecane‐5,11‐dione (HTDD) was applied to synthesize hexanitro‐2,4,6,8,10,12‐hexaazatricyclo[7,3,0,03,7]dodecane‐5,11‐dione (HHTDD) and its derivatives. The calculation of the electrostatic potential (ESP) shows that the non‐ionic precursor has a stronger electrophilic reactivity compared to the previous ionic analogue, which is also verified by nitrification experiments. 90 % HNO3 was reacted with the ionic precursor and the non‐ionic precursor, respectively, and only the latter can obtain a full nitrification product. All nitrification products with different nitro group numbers were characterized by FT‐IR, NMR, element analysis, DSC, TG and single‐crystal XRD. The hydrolytic stability was tested in different concentrations of acidic and alkaline solutions. The impact and friction sensitivities were measured. Further the detonation parameters were determined according to the Kamlet‐Jacobs equations based on calculated heats of formation (B3LYP) and measured densities. The results show that the non‐ionic precursor has a stronger electrophilic reactivity and is easier to react with NO2+. Applying a non‐ionic precursor is a very efficient method for promoting nitrating reactions.
A Facile Synthesis of Indole Derivatives by a Palladium‐Catalyzed Process Initiated from Ugi Adducts and their Antifungal Activities
Authors: Qiu Ji‐Ying , Yuan Ding , Yu Jing‐Jing , Zhang Yi , Li Wen‐Hao , Tang Zeng‐Xiang , He Ping , Ren Zhi‐Lin
Published: December 2021

In this work, an efficient synthesis of indole derivatives through palladium‐catalyzed double isocyanide insertion reactions has been developed. The reaction intermediates could be readily obtained by Ugi reactions. The transformation features broad functional‐group compatibility, commercially available starting materials, and moderate to good reaction yields. Furthermore, the bioactivities of the synthesized compounds were evaluated in mycelial growth tests against Penicilium digitatum and Colletotrichun gloeosporioides, and showed potential antifungal activities.
Platinum Crosslinked Carbon Dot@TiO2−x p‐n Junctions for Relapse‐Free Sonodynamic Tumor Eradication via High‐Yield ROS and GSH Depletion
Authors: Geng Bijiang , Xu Shuang , Li Ping , Li Xiaokai , Fang Fuling , Pan Dengyu , Shen Longxiang
Published: December 2021

Sonodynamic therapy as a promising noninvasive modality is being developed for tumor therapy, but there is a lack of next‐generation sonosensitizers that can generate full ROS at high yields and simultaneously deplete elevated levels of glutathione (GSH) in tumor cells. Semiconductor p‐n junctions are engineered as high‐efficacy sonosensitizers for sonodynamic tumor eradication using pyridine N‐doped carbon dots (N‐CDs) as a p‐type semiconductor and oxygen‐deficient TiO2−x nanosheets as a n‐type semiconductor. The rate constants of 1O2 and •OH generation by ultrasound‐excited N‐CD@TiO2−x p‐n junctions are 4.3 and 4.5 times higher than those of TiO2, respectively. A Z‐scheme carrier migration mechanism in the p‐n junction achieving the rapid spatial separation of the ultrasound‐generated electron–hole pairs for enhanced full ROS production is proposed. GSH‐cleavable, Pt‐crosslinked, N‐doped CD fluorescent probes to detect the presence of intracellular GSH are also constructed. A GSH‐responsive, p‐n junction platform (Pt/N‐CD@TiO2−x) with integrated GSH detection, GSH depletion, and enhanced sonodynamic performance is then assembled. Malignant tumors are completely eradicated without relapse via intravenous administration of low‐dose Pt/N‐CD@TiO2−x under ultrasound irradiation. This work substantiates the great potential of biocompatible, GSH‐responsive p‐n junctions as next‐generation sonosensitizers via p‐n junction‐enhanced ROS generation and metal ion oxidation of intracellular GSH.
Bismuth Nanoparticles Encapsulated in Nitrogen‐Rich Porous Carbon Nanofibers as a High‐Performance Anode for Aqueous Alkaline Rechargeable Batteries
Authors: Zhou Kai , Wang Shuai , Guo Xinying , Zhong Guixiang , Liu Zhenbang , Ma Yingming , Wang Haoyu , Bao Yu , Han Dongxue , Niu Li
Published: December 2021

The aqueous alkaline rechargeable batteries (AARBs) have an attractive potential for electrochemical energy storage devices. In view of the advantages of high theoretical capacity and desirable negative operating window, bismuth (Bi) has been deemed as a hopeful anode material for AARBs. Unfortunately, intensive reported works of Bi anode are still confronted with limited capacity and poor cycling stability. Herein, the designed electrodes of different size Bi nanoparticles embedded in porous carbon nanofibers with a contrasting nitrogen doping content are obtained by electrospinning and thermal treatment processes. The effect of the N dopant in carbon shell is demonstrated on the Bi core, which is in favor of enhancing the capacity of Bi anodes. More importantly, the core structure with highly dispersed ultrasmall Bi nanoparticles (<20 nm) in carbon matrix plays a crucial role in long‐term durability. Accordingly, the optimized polydisperse ultrasmall Bi nanoparticles confined in N‐rich porous carbon nanofibers electrode (Bi@NPCF) presents an admirable capacity of 196.1 mAh g−1 at 3 A g−1 and outstanding durable lifespan (retain 116.95% after 10 000 cycles). In addition, the fabricated Bi@NPCF//NiCo2O4 battery exhibits an exceptional energy and power density with durable stability (95.9% after 5000 cycles).
Co‐Assembly of Colloids and Eumelanin Nanoparticles in Droplets for Structural Pigments with High Saturation
Authors: Han Sang Hoon , Choi Ye Hun , Kim Shin‐Hyun
Published: December 2021

Colloidal crystals have been used to develop structural colors. However, incoherent scattering causes the colors to turn whitish, reducing the color saturation. To overcome the problem, light‐absorbing additives have been incorporated. Although various additives have been used, most of them are not compatible with a direct co‐assembly with common colloids in aqueous suspensions. Here, the authors suggest eumelanin nanoparticles as a new additive to enhance the color chroma. Eumelanin nanoparticles are synthesized to have diameters of several nanometers by oxidative polymerization of precursors in basic solutions. The nanoparticles carry negative charges and do not weaken the electrostatic repulsion among same‐charged polystyrene particles when they are added to aqueous suspensions. To prove the effectiveness of eumelanin as a saturation enhancer, the authors produce photonic balls through direct co‐assembly of polystyrene and eumelanin using water‐in‐oil emulsion droplets, while varying the weight ratio of eumelanin to polystyrene. The high crystallinity of colloidal crystals is preserved for the ratio up to at least 1/50 as the eumelanin does not perturb the crystallization. The eumelanin effectively suppresses incoherent scattering while maintaining the strength of structural resonance at an optimum ratio, improving color chroma without compromising brightness.
Die Capricorn‐Brücke im Düsseldorfer Medienhafen
Authors: Mähl Florian , Hartl Günter , Kloft Harald
Published: December 2021

Im Süden des Düsseldorfer Medienhafens sind innerhalb kurzer Zeit zwei moderne Bürogebäude in nächster Umgebung zueinander entstanden, zum einen das Capricornhaus der Architekten Gatermann+Schossig und das Float von Renzo Piano Building Workshop. Ursprünglich unabhängig voneinander geplant, beherbergen beide Gebäude heute gemeinsam die Firmenzentrale eines internationalen Konzerns. Zur Verbesserung der internen Erschließung wurden Supergelb Architekten und osd – office for structural design beauftragt, eine verbindende, witterungsgeschützte Fußgängerbrücke zu entwerfen. Die komplexe Form der kristallin wirkenden und allseitig mit polygonalen Isolierglaselementen bekleideten Capricorn‐Brücke leitet sich her aus den unterschiedlichen Gebäudeachsen, den verspringenden Zugängen in die bestehenden Fassaden sowie der zentralen Gründung im Straßenraum. Das 35 m lange Brückenbauwerk setzt sich gestalterisch von den Nachbargebäuden ab und markiert einen eigenständigen Baukörper im Straßenraum, der von außen wie ein geschliffener Diamant wirkt. Die Capricorn‐Brücke lagert auf einem zentralen, massiven Sockel aus Stahlbeton, von welchem das räumliche Stabwerk aus Stahlhohlprofilen in beide Richtungen zu den Andockpunkten hin auskragt. Durch die zentrale Gründung in Fahrbahnmitte ergaben sich für Tragwerks‐ und Fassadenplanung besondere Anforderungen.
Moment–rotation curve characteristics and initial rotational stiffness calculation method of angle connections
Authors: Qin Jiangui , Wang Zhan , Pan Jianrong , Li Bin , Fan Yanjing
Published: December 2021

Due to recent advances in computational power, high efficiency and high precision semi‐rigid calculation methods of steel connections are necessary. In this paper, four connection experiments were designed to study the mechanical behavior of the top and seat angle connections. In the experiment, a monotonic load was applied at the end of the beam to study its moment–rotation characteristics. In addition, this paper proposed a second derivative method to determine the yield point, the starting point of the plastic strengthening stage, and the initial rotational stiffness of the connections according to the moment–rotation curve. Loading test experiments (EX) results and finite element analysis (FEA) results showed that the compression side angle stiffener has little effect on the initial rotational stiffness. Nevertheless, it can delay the top and seat angle connection in entering the elastoplastic stage and the starting point of the plastic strengthening stage. The results also showed that the tension side angle stiffener could significantly increase the initial rotational stiffness, but makes the angle connection enter the yield stage earlier. When the connection's top and seat angles have no stiffener, the elastoplastic deformation range on the curve is smaller. Finally, based on the theory of Plates and Shells, this paper proposed the calculation method for the deformation stiffness of the key components and the initial rotational stiffness of the connection. Results from the theoretical calculation method showed high calculation accuracy and high calculation efficiency, as compared with the EX and the FEA results.
Research on vertical deformation and predeformation control of three‐tower connected super high‐rise structure during construction
Authors: Yuan Zhijie , Sun Guangjun , Wu Xiaoping , Li Hongjing , Kong Lei
Published: December 2021

Connected super high‐rise structure has a long construction period and significant time‐dependent characteristics, so it is necessary to study its vertical deformation during construction. Taking an asymmetrical three‐tower conjoined super high‐rise structure as engineering background, the equivalent elasticity problem was analyzed by age‐adjusted effective modulus method, and vertical deformation formula was deduced. A simplified model and a refined model of structure were established. The correctness of the deformation formula and modeling had been proven by comparing the dynamic characteristics and numerical simulation results. Based on the simplified model, the optimal construction plan of the conjoined super high‐rise structure was discussed. Based on the deformation formula, the predeformation calculation method of the conjoined super high rise was studied, and the correctness was verified by numerical simulation. The results show that the largest vertical deformation of the connected structure occurs at the position of corridor, and an apparent mutation occurs here. Properly delaying the rigid connection timing between corridor and tower is beneficial to the control of the overall structural deformation difference and internal force. The predeformation analysis method proposed in this paper is correct and effective, which could offset the vertical deformation of the structure during the construction sequence.
Process Intensification of Enzymatic Synthesis of Flavor Esters: A Review
Authors: Jaiswal Kajal S. , Rathod Virendra K.
Published: December 2021

The conventional flavor synthesis method suffers from low yields, time inefficiency, and extreme reaction conditions. Therefore, there is a necessity for the green and novel synthesis approach to overcome these limitations. The current review presents a holistic insight into different aspects associated with the synthesis of flavor esters using the immobilized enzyme. The application of process intensification tools such as ultrasound and microwave irradiation can enhance the reaction efficiency because of higher product recovery, less formation of by‐products, and decreased energy consumption. This review presents the process intensification of value‐added flavor esters synthesis and the mechanism of ultrasound and microwave action on the enzyme to enhance the enzyme activity and increase the reaction rate. It also summarizes the role of process intensification in enzymatic flavor ester synthesis, followed by specific examples as reported in the literature.
Seasonal variation in resource selection by subadult golden eagles in the Great Basin Desert
Authors: Hixson Kathy M. , Slater Steven J. , Knight Robert N. , Lonsinger Robert C.
Published: December 2021

Golden eaglesAquila chrysaetosare a long‐lived and wide‐ranging species believed to be stable or in slight decline across North America. Golden eagles have an extended subadult stage (4–5 years) that is critical to maintaining recruitment into the breeding population and population viability. Compared to adult golden eagles, the ecology of subadult golden eagles (hereafter, subadults) has received little attention. We investigated patterns of resource selection for subadults in the Great Basin Desert of the western United States during summer and winter, 2013–2019. We monitored 46 subadults with GPS transmitters and related locations (n = 99 037) with predictors hypothesized to influence seasonal patterns of space use with mixed‐effects logistic regression. Subadults selected for ridges and upper slopes in summer and winter, but higher elevations in summer. Subadults showed weak selection for lower ridge density in summer, which was likely facilitated by selection for areas with greater thermal wind current potential. In contrast, subadults showed strong selection for higher ridge density in winter. Subadults selected areas further from roads in summer and closer to roads and electrical transmission lines in winter, which may be related to winter scavenging of road‐killed ungulates. Resource selection functions suggested subadults selected for shrublands and woodlands in both seasons, but odds ratios revealed that during winter subadults avoided shrublands and increased selection of woodlands relative to summer. Subadults selected for areas with infrequent fires in both seasons; areas with frequent fires were avoided in summer but selected for in winter. Seasonal changes in resource selection suggested that subadults used woodlands more than expected, potentially reflecting spatial partitioning by subadults to lower‐quality habitats to minimize competition with breeding adults during winter when energetic demands for thermoregulation were presumably higher and prey more limited.