bluuebunny/crossref_metadata_2025 huggingface dataset:
Microalgae biotechnology as a promising pathway to ecofriendly aquaculture: a state‐of‐the‐art review
Authors: Li Huankai , Chen Sihua , Liao Kang , Lu Qian , Zhou Wenguang
Published: November 2020

Aquaculture is an important industry providing high‐quality animal protein to humans, but it brings serious environmental pollutions, such as eutrophication of water bodies and the abuse of antibiotics. Microalgae cultivation, which can recover nutrients, release oxygen and yield value‐added biomass, has been studied intensively as a promising biotechnology for aquaculture wastewater treatment and fish diet production. Herein, we introduce a novel concept of applying microalgae biotechnology in aquaculture by integrating wastewater remediation, biomass harvesting and aquatic animals rearing systems. We review recent progress in aspects of value‐added algal species screening, algae cultivation systems design, nutrient recovery by algal–bacterial interactions, and biomass harvesting technologies. Finally, we discuss some problems, including bacterial contamination, unfavorable conditions in effluent and lack of technological assessment, which may hinder the application of microalgae biotechnology. It is expected that this paper could attract researchers' and technicians' attention to the microalgae‐based pollution control and promote the development of ecofriendly aquaculture. © 2020 Society of Chemical Industry
Accelerated desalting and purification of silk fibroin in a CaCl2‐EtOH‐H2O ternary system by excess isopropanol extraction
Authors: Zhang Meng , Weng Yu‐Jie , Zhang Yu‐Qing
Published: November 2020

BACKGROUND

Silk fibroin has attracted extensive attention due to its useful biological properties. However, in the regeneration process of silk fibroin, the need for highly concentrated neutral salt dissolution and long‐term dialysis greatly hinder the development of silk biomaterials.

RESULTS

A 3‐fold volume of isopropanol (IP) was added to one volume of 20% (w/v) silk fibroin solution dissolved in a CaCl2‐EtOH‐H2O ternary system (SFTS) to extract the protein. The extraction resulted in the precipitate consisted of aggregated silk fibroin in the SFTS. The extracted protein was easily resolubilised in water. Compared with the original dialysis time required for the SFTS, the dialysis time of the extracted protein was shortened by nearly half. When the SFTS was diluted with a 2.5‐fold volume of water, the same IP extraction resulted in the dialysis time being shortened by two thirds. SDS‐PAGE showed that IP extraction did not cause breakage of the silk peptide chain. FTIR and X‐ray diffraction indicated this extraction had no influence on the secondary structure of silk fibroin.

CONCLUSION

Excess IP extraction effectively accelerates the desalting and purification of fibroin in a CaCl2‐EtOH‐H2O ternary system without affecting the protein structure, thus greatly improving the regeneration efficiency of silk fibroin. © 2020 Society of Chemical Industry
Strong‐Induced CPL Emission Promoted from Achiral Conjugated Polymer‐Containing Emissive Nematic Liquid Crystals (P‐N*‐LCs)
Authors: Chen Yihan , Xu Zhaoran , Hu Wenrui , Li Xiaojing , Cheng Yixiang , Quan Yiwu
Published: November 2020

With the rapid development on 3D printing technology, more and more works have been devoted to 3D display. 3D display will really come true by using circularly polarized luminescence (CPL)‐active materials with both high quantum yield and dissymmetry factor (gem) in organic light‐emitting diode or liquid crystals (LCs). But so far most of these CPL materials cannot meet the real application requirement because of the low gem values in the range of 10−5–10−2. In this paper, ternary chiral emissive LCs (P‐N*‐LCs) is designed by doping chiral binaphthyl‐based enantiomers as chiral dopant (Guest 1) and achiral conjugated polymer as induced CPL emitter (Guest 2) into nematic liquid crystal (N‐LCs) Host 5CB. Both Guest 1 and Guest 2 show excellent compatibility with Host 5CB. The obtained ternary P‐N*‐LCs can emit strong‐induced CPL signal with gem up to 1.12 and ФFL up to 66.1%. This work first develops a new strategy for the smart design of excellent CPL materials from versatile achiral conjugation fluorescence polymers.
Multiarm Star‐Crosslinked Hydrogel: Polymer Network with Thermoresponsive Free‐End Chains Densely Connected to Crosslinking Points
Authors: Ida Shohei , Toda Shogo , Oyama Masatoshi , Takeshita Hiroki , Kanaoka Shokyoku
Published: November 2020

Soft tissue in biological system is a hydrogel with elaborate structure exhibiting repeatable dynamic function. In order to approach such sophisticated system, precise construction of a designed network with multi‐components is desired. This communication presents a novel hydrogel having highly dense stimuli‐responsive free‐end chains around crosslinking structure. A key molecule is a core‐crosslinked star‐shaped polymer with multiple thermoresponsive arms, which can be prepared by reversible addition–fragmentation chain transfer polymerization of divinyl crosslinker with poly(N‐isopropylacrylamide) (PNIPAAm) macro‐chain transfer agent and have a number of unreacted carbon–carbon double bonds in the core. These unreacted double bonds can be utilized as a crosslinker for poly(acrylamide) (PAAm) gel synthesis by free radical polymerization. The obtained gel contains homogeneously dispersed star PNIPAAms as crosslinking points and exhibits thermoresponsive swelling behavior in water depending on the star contents. In particular, the gel with low content of the star crosslinker shows localized responsive behavior with expansion and shrinkage of the star in one molecule. The mechanical properties of the star‐crosslinked gel are significantly high compared to the conventional PAAm gels particularly in compressive strength (≈9 MPa). Moreover, the star‐crosslinked gel has thermoresponsive mechanical toughening property.
On the Klein‐Gordon‐Maxwell system with critical exponential growth in ℝ2
Authors: Chen Sitong , Lin Xiaoyan , Tang Xianhua
Published: November 2020

This paper is concerned with the following Klein‐Gordon‐Maxwell system:

where ω > 0 is a constant,
,
and
obeys exponential critical growth in the sense of the Trudinger‐Moser inequality. We give some new sufficient conditions on f, specifically related to exponential growth, to obtain the existence of nontrivial solutions. Furthermore, we prove a nonexistence result with a Pohozaev‐type argument which also provides important information to get the above existence results. In particular, some new analytical approaches and estimates are used to overcome the difficulty arising from the critical growth of Trudinger‐Moser type.
A lightweight and high thermal performance graphene heat pipe
Authors: Liu Ya , Chen Shujing , Fu Yifeng , Wang Nan , Mencarelli Davide , Pierantoni Luca , Lu Hongbin , Liu Johan
Published: November 2020

Heat pipe is one of the most efficiency tools for heat dissipation in power systems. Currently, heat pipes are usually made of copper or aluminum. However, due to their relatively high density and limited heat transmission capacity, heat pipes are facing urgent challenges in power electronics. In this paper, a new class of graphene enhanced heat pipe that can cope with these issues is reported. The graphene enhanced heat pipe is made of high thermal conductivity graphene assembled film with nanostructure enhanced inner surfaces. The study shows that the dramatically improved heat dissipation capacity, 7230 W m−2 K−1 g−1, about 3.5 times higher than that of copper based commercial heat pipes can be achieved. This paves the way for using graphene enhanced heat pipe in lightweight and large capacity cooling applications, as required in many systems such as automotive electronics, hand‐sets and space electronics.
Clinical features, comorbidities, complications and treatment options in severe and non‐severe COVID‐19 patients: A systemic review and meta‐analysis
Authors: Giri Mohan , Puri Anju , Wang Ting , Guo Shuliang
Published: November 2020

Objectives

The aim of this analysis was to assess the prevalence of clinical features, comorbidities, complications and treatment options in the patients with COVID‐19 and compare incidence of these clinical data in severe and non‐severe patients.

Design

Systemic review and Meta‐analysis.

Methods

PubMed, Embase, Scopus and Web of Sciences databases were searched to identify relevant papers until 20 July 2020. All studies comparing clinical data of severe and non‐severe patients of COVID‐19 were included. Heterogeneity across included studies was determined using Cochrane's Q test and the I2 statistic. Results were expressed as odds ratio with accompanying 95% confidence intervals.

Results

Twelve studies with 3,046 patients were included. The result showed the most prevalent clinical symptoms were fever 88.3%, cough 62.2%, fatigue 39.5% and dyspnoea 31.5%. Further meta‐analysis showed incidence of fever, cough, fatigue and dyspnoea was higher in severe patients. The most prevalent comorbidities were hypertension 22.6%, diabetes 11.5%, cardiovascular disease 10.3% and cancer 2.5%. We found that compared with non‐severe patients, the symptoms, existing comorbidities and complications are prevalent in severe COVID‐19 patients. Future well‐methodologically designed studies from other populations are strongly recommended.
A review of knowledge, attitude, and practice towards COVID‐19 with future directions and open challenges
Authors: Gupta Puneet Kumar , Kumar Aishwarya , Joshi Sudhanshu
Published: November 2020

In most of the affected country's ignorance of Knowledge, Attitude, and Practice (KAP) towards COVID‐19 leads to several issues. The aim of the present study is to review and discuss the KAP to fight the COVID‐19 crisis in respect of stakeholders namely, general populations, health workers, and students. A comprehensive search of the literature associated with KAP towards COVID‐19 is made using various keywords through PubMed, Web of Science, and Scopus and based on the results; a brief review is done by assessing the various aspects like country, sample size, and so forth. A detailed structure is provided with the KAP towards COVID‐19 to overwhelm the significant impact of the explosion. Though, various studies appear in the literature as a result of sufficient element of knowledge, positive attitude, and necessary practice, yet there are various challenges in front of the authority bodies as this pandemic becoming critical day by day. Incessant progress in the KAP has contributed well in the fight against the pandemic and we believe that providing proper information to related COVID‐19 would help in tackling this disease, especially, when authorities started talking with COVID‐19 for a long period or until a vaccine developed.
Ultra‐efficient intrinsic‐vertical‐tunnel‐junction structures for next‐generation concentrator solar cells
Authors: Seoane Natalia , Fernández Eduardo F. , Almonacid Florencia , García‐Loureiro Antonio
Published: November 2020

The efficiency of solar cells can be enhanced by increasing the light intensity and/or the number of bandgaps of the structure. However, current solar cells cannot fully exploit these two factors because of various critical drawbacks. Here, we show a novel microscale, that is, side ≈ 0.5 mm, vertical solar cell structure that does not suffer the series resistance and bandgap limitations issues of current devices. The preliminary structures investigated show extreme efficiencies, >40%, at ultrahigh concentration factors of 15 000 suns. In addition, future designs with a better bandgap configuration are expected to deliver cells with efficiencies far above 50% at extreme light intensities. This early design offers a fast and reliable route to push the efficiency towards the maximum solar conversion limit and represents a promising way to develop new‐generation ultraefficient and low‐cost concentrator photovoltaic systems.
Computational design of small molecular modulators of protein–protein interactions with a novel thermodynamic cycle: Allosteric inhibitors of HIV‐1 integrase
Authors: Sun Qinfang , Ramaswamy Vijayan S. K. , Levy Ronald , Deng Nanjie
Published: November 2020

Targeting protein–protein interactions for therapeutic development involves designing small molecules to either disrupt or enhance a known PPI. For this purpose, it is necessary to compute reliably the effect of chemical modifications of small molecules on the protein–protein association free energy. Here we present results obtained using a novel thermodynamic free energy cycle, for the rational design of allosteric inhibitors of HIV‐1 integrase (ALLINI) that act specifically in the early stage of the infection cycle. The new compounds can serve as molecular probes to dissect the multifunctional mechanisms of ALLINIs to inform the discovery of new allosteric inhibitors. The free energy protocol developed here can be more broadly applied to study quantitatively the effects of small molecules on modulating the strengths of protein–protein interactions.
Investigation of β‐Ga2O3 Film Growth Mechanism on c‐Plane Sapphire Substrate by Ozone Molecular Beam Epitaxy
Authors: Feng Boyuan , Li Zhengcheng , Cheng Feiyu , Xu Leilei , Liu Tong , Huang Zengli , Li Fangsen , Feng Jiagui , Chen Xiao , Wu Ying , He Gaohang , Ding Sunan
Published: November 2020

Growth mechanism and temperature of monoclinic gallium oxide (β‐Ga2O3) films grown by ozone molecular beam epitaxy (MBE) are investigated herein. Phase‐pure () β‐Ga2O3 films can be grown on c‐plane sapphire substrates when the growth temperature exceeds 500 °C, and the grain size increases with the increase in the growth temperature. Sixfold rotational domains are obtained based on the epitaxial relationships (Ga2O3 < 010>//Al2O3<> and Ga2O3 < 102>//Al2O3 < 110>). For the film grown at 700 °C, the threefold facets are observed for the first time, which are resulted from the easy‐cleaved (100) plane and rotational domains. In addition, the cathodoluminescence spectra of the β‐Ga2O3 films show that the proportion of ultraviolet emission increases with the increase in the growth temperature, which is attributed to the modulation of defect. Finally, the growth rate can be modulated by the ratio of Ga flux and ozone pressure. A reference is provided for heteroepitaxy of β‐Ga2O3 films and better understanding of the ozone MBE growth mechanism of oxides.
Effects of Surface Orientation and Termination Plane on Glass‐to‐Crystal Transformation of Lithium Disilicate by Molecular Dynamics Simulations
Authors: Sun Wei , Dierolf Volkmar , Jain Himanshu
Published: November 2020

Glass‐to‐crystal transformation of lithium disilicate is studied using molecular dynamics simulations using an effective partial charge potential. The structural evolution of the interface between glassy and crystalline lithium disilicate is analyzed to simulate crystallization of glass on pre‐existing crystal seeds. Besides previously used atomic number density, the distribution of Qn species (Si tetrahedra with n bridging oxygen) is shown to be an effective parameter for following this transformation quantitatively. The early stages of crystal growth are significantly affected by the orientation and termination of the surface of adjacent crystal, as indicated by calculated atomic density, partial ordering, atomic segregation, and an increase in Q3 concentration. In particular, under‐coordinated Si within the outer crystal layer is found to be most effective in transforming the amorphous structure toward crystallinity. The increase in Q3 in the glass close to interface region most clearly shows the initial stage of lithium disilicate crystal growth.
Hybrid‐Functional Study of Native Point Defects and Ti/Fe Impurities in α‐Al2O3
Authors: Palakawong Nirawith , Sukharom Siwakorn , Limpijumnong Sukit , Jungthawan Sirichok , Limkumnerd Surachate , Boonchun Adisak , Reunchan Pakpoom , T‐Thienprasert Jiraroj
Published: November 2020

First‐principles calculations with the most accurate hybrid functional are used to investigate the effect of native point defects and Ti/Fe impurities on electrical and optical properties of α‐Al2O3. For dominant native point defects, the Al vacancy (VAl), O vacancy (VO), and Al interstitial (Ali) defects are considered, and it is found that only VAl defect provides the absorption line in the visible light region. Regarding Ti‐doped or Fe‐doped sapphire, it is found that their colors should be related to intra‐atomic d–d transitions. For the Ti–Fe pair, it is found that the ground‐state configuration is TiIII–FeIII, and its binding energy is very high, indicating that this pair can exist in high concentration. The calculated optical absorption energy associated with Ti–Fe pair is ≈1.92 and 1.84, which is appropriate for sapphire to be blue. It is, therefore, suggested that the intervalence charge transfer (IVCT) mechanism is the cause of blue color in blue sapphire.
Optical response of plasma processed quantum dot under the external fields
Authors: Kılıç Kadir , Bahar Mustafa Kemal
Published: November 2020

We investigate theoretically the total refractive index changes (TRICs) and the total absorption coefficients (TACs) of two‐electron Gaussian quantum dot (TEGQD) including Gaussian potential confinement generated by GaAs/GaAlAs heterostructure, embedded in Debye and quantum plasma environments modeled by the more general exponential cosine screened Coulomb (MGECSC) potential, under the influence of the external electric and magnetic field. The wave equation is solved within the effective mass approach framework by using Runge–Kutta–Fehlberg method in order to obtain the subband spectra and the electronic wave functions of TEGQD. Nonlinear optical response of TEGQD is obtained through the compact‐density‐matrix formalism within the iterative method. The effects of both Debye and quantum plasma environments in the strong and weak regimes of the external fields are considered and compared throughout the study. The potents of the external electric field, the external magnetic field, the quantum dot width, the barrier height, and the plasma screening on TRICs and TACs resonant frequencies and amplitudes are analyzed. In addition to these analyses, the alternatives to each parameter effects of the model are also elucidated. TRICs and TACs analyze are carried out in a plasma‐free environment, and thus the function of environments with plasma compared to that without plasma is better explained. Thanks to all these reviews, it is elucidated how to and at what ranges perform in terms of the incident photon energy of TEGQD's optimum for TRICs and TACs characters by using plasma, and in which cases it will be an alternative to the external field and geometrical encompassing.
Alkalinity gradients in grasslands alter soil bacterial community composition and function
Authors: Xiang Junliang , Jin Jian , Liu Quan , Huang Yulan , Wu Wensi , Tang Ruixi , Chen Yuan , Yin Kuide
Published: November 2020

Clarifying the bacterial community composition and function in alkali soils is pivotal to the soil capability of sustaining venerable ecosystems. Using MiSeq sequencing, PICRUSt, and Biolog (https://www.biolog.com), we investigated the bacterial community composition and metabolic function of microbes in three soils differing in the severity of alkalinity. A high level of alkalinity deceased the diversity of microbial community and altered microbial community composition with the increase in relative abundances of 21 genera. The linear discriminate analysis and effect size analysis found most of 54 biomarkers belonged to Actinobacteria and Proteobacteria. Redundancy analysis indicated that the succession of bacterial community and metabolic characteristics of microbes were highly affected by the nutrient availability and soil moisture. The utilization rates of carbohydrates, amino acids, carboxylic acids, polymers, phenolic compound, and aminesides by microbes were positively correlated with soil nutrient concentrations but negatively correlated with the exchangeable sodium percentage and pH. Severe alkalinity inhibited the microbial community diversity and function on carbohydrate metabolisms.
Adaptive enrichment trials: What are the benefits?
Authors: Burnett Thomas , Jennison Christopher
Published: November 2020

When planning a Phase III clinical trial, suppose a certain subset of patients is expected to respond particularly well to the new treatment. Adaptive enrichment designs make use of interim data in selecting the target population for the remainder of the trial, either continuing with the full population or restricting recruitment to the subset of patients. We define a multiple testing procedure that maintains strong control of the familywise error rate, while allowing for the adaptive sampling procedure. We derive the Bayes optimal rule for deciding whether or not to restrict recruitment to the subset after the interim analysis and present an efficient algorithm to facilitate simulation‐based optimisation, enabling the construction of Bayes optimal rules in a wide variety of problem formulations. We compare adaptive enrichment designs with traditional nonadaptive designs in a broad range of examples and draw clear conclusions about the potential benefits of adaptive enrichment.
Experimental Findings about the Fluorescence Emission of Generation 4.0 and 4.5 Polyamidoamine Dendrimers
Authors: E. Ybarra David , Igartúa Daniela E. , del V. Alonso Silvia , C. Alvira Fernando
Published: November 2020

Physicochemical characterization of polyamidoamine (PAMAM) dendrimers of generation 4.0 amine‐terminated (DG4.0) and 4.5 carboxy‐ended (DG4.5) was done. We have measured the pKa of the inner tertiary amine, the surface primary‐amine, and carboxyl‐terminal groups. We have conducted UV‐Vis absorption and fluorescence emission experiments as a function of pH. We have made a 4th derivative analysis of the UV‐Vis absorption experiments and compare the results with classical amide such as dimethylformamide. Our results have permitted us to calculate the pKa of the groups sensible to the pH in both dendrimers and compare the results with theoretical studies. On the one hand, the pKa values found for DG4.0 were 10.0±0.5 and 7.1±0.2, for primary and tertiary amines groups, respectively. On the other hand, the pKa values found for the DG4.5 were 3.5±0.7 and 6.8±0.4, for the carboxylic and tertiary amine groups. Our experimental results agree with theoretical ones. We offer probes that the dendrimers have two non‐traditional fluorophores, where one of them is the inner amide bond. The dendrimers show fluorescence emission in all the tested pH.
Electrospun Polycaprolactone Scaffolds Using an Ionic Liquid as Alternative Solvent: Morphometric, Mechanical and Biological Properties
Authors: Da Silva Bernardo A. , Valério Alexsandra , Cesca Karina , Hotza Dachamir , Gómez González Sergio Yesid
Published: November 2020

Ionic liquids (IL) are a greener alternative to aggressive organic solvents used for biopolymers dissolution in the electrospinning process. Nevertheless, the effect of IL on the properties of the electrospun materials is still a gap. In this work, we obtain polycaprolactone (PCL) electrospun mats using two solvents, either trichloromethane (CHCl3) – a conventional toxic and carcinogenic solvent – or 1‐butyl‐3‐methylimidazolium chloride ([Bmim]Cl), an ionic liquid. The differences between the respective electrospun products were assessed through the scaffold's morphology, mechanical properties and cytotoxicity. The use of IL resulted in the formation of textured thinner fibers, enhancing the surface area in 43 %. IL induced a lower rupture stress and elongation of the mats of 34 and 39 %, respectively, while the elastic modulus and yield stress did not present significant differences. The cytotoxicity assays using L929 cells detected a number of viable cells slightly higher for the scaffold produced with IL. Cell interaction tests also revealed that L929 cells adhere and proliferate on both scaffolds. However, the cell adhesion was higher for the mats fabricated using IL. Beyond the results, this work sheds light on the pros and cons of tissue engineering scaffolds produced with the aid of less hazardous solvents.
P‐doped TiO2 Nanofibers Decorated with Ag Nanoparticles for Enhanced Photocatalytic Activity under Simulated Solar Light
Authors: Ghafoor Samina , Aftab Faryal , Rauf Ali , Duran Hatice , Kirchhoff Katrin , Arshad Salman N.
Published: November 2020

We report the synthesis of titania nanofibers (TNF) of ∼195 nm mean diameter doped with phosphorus through one‐pot electrospinning followed by decoration of Ag nanoparticles (NPs). The Ag NPs of ∼8 nm size on 2 % P‐doped TNFs (Ag‐PTNFs) showed excellent photocatalytic activity for the reduction of Cr(VI), under simulated solar light, with ∼100 % conversion to Cr(III) in 90 min at pH 3 with a pseudo‐first order rate constant of 0.085 min−1 that is 96.5 % higher than TNFs. The Ag‐PTNFs also exhibited excellent photodegradation of methylene blue with pseudo‐first order rate constant of 0.052 min−1 which is 82.7 % better than TNFs. The enhanced photocatalytic performance of Ag‐PTNFs is attributed to the reduced band‐gap, increased charge separation and reduced recombination rates. A proposed photocatalytic mechanism based on the synergistic effect of both Ag and P doping is presented which highlights the potential of these composite materials for water remediation.
Evaluation of a Tubulin‐Targeted Pyrimidine Indole Hybrid Molecule as an Anticancer Agent
Authors: Bose Chandra , Banerjee Priyanjalee , Kundu Jayanta , Dutta Biswadeb , Ghosh Indranil , Sinha Shreya , Ghosh Argha , Barua Abhishek , Gupta Shalini , Das Ujjal , Jana Siddhartha S. , Sinha Surajit
Published: November 2020

Several small molecules targeting microtubule dynamics have been developed because microtubules are considered to be one of the most successful cancer chemotherapeutic targets. In this regard, taxol is most worthy to mention which stabilizes microtubule polymer thereby causing defectsinmitotic spindle assembly, chromosome segregation and cell division resulting in cancer inhibition. In this direction, we have earlier reported a small molecule called Pyrimidine‐Indole‐Hybrid (PIH (P)) which was found to inhibit ciliogenesis by inhibiting both the acetylation and polymerization of tubulin subunits. Here, we have evaluated the anticancer activities of PIH (P) and its water soluble derivatives. Three water soluble derivatives of PIH (P) namely 6 A, 6B and 6 C were synthesized. Among PIH (P) series of compounds, PIH (P) and 6 C were found to be the most potent compounds showing anti‐proliferative and cytoskeletal disrupting activities against MCF‐7 cells. Not only that, PIH (P) and 6 C also showed a promising effect in preventing cancer cell migration, invasion and colony‐formation and helped to reduce spheroid formation by several‐folds. They have potential to inhibit the activity of proteins (N‐Cadherin, Vimentin) responsible for Epithelial to Mesenchymal Transition (EMT). Hence, this class of compound could be a new antimitotic agent that is different from taxol with respect to mechanism, particularly by destabilizing tubulin rather than causing stabilization.
Mechanochemically Induced Chalcogenation of Bicyclic Arenes under Solvent‐, Ligand‐, Metal‐, and Oxidant‐Free Conditions
Authors: Panja Subir , Paul Biprajit , Jalal Swapnadeep , Ghosh Tubai , Ranu Brindaban C.
Published: November 2020

A convenient method has been developed for the synthesis of biarenyl chalcogenides through the interaction of bicyclic arenes and diaryl dichalcogenides on the surface of basic alumina under ball milling without any metal catalyst or solvent. This methodology shows wide substrate scope and is of high potential in organic synthesis due to its green aspects of ease of operation, shorter reaction time, ambient conditions and high yields.
Recent Progress on NiFe‐Based Electrocatalysts for the Oxygen Evolution Reaction
Authors: Zhao Jia , Zhang Ji‐Jie , Li Zhao‐Yang , Bu Xian‐He
Published: November 2020

The seriousness of the energy crisis and the environmental impact of global anthropogenic activities have led to an urgent need to develop efficient and green fuels. Hydrogen, as a promising alternative resource that is produced in an environmentally friendly and sustainable manner by a water splitting reaction, has attracted extensive attention in recent years. However, the large‐scale application of water splitting devices is hindered predominantly by the sluggish oxygen evolution reaction (OER) at the anode. Therefore, the design and exploration of high‐performing OER electrocatalysts is a critical objective. Considering their low prices, abundant reserves, and intrinsic activities, NiFe‐based bimetal compounds are widely studied as excellent OER electrocatalysts. Moreover, recent progress on NiFe‐based OER electrocatalysts in alkaline environments is comprehensively and systematically introduced through various catalyst families including NiFe‐layered hydroxides, metal–organic frameworks, NiFe‐based (oxy)hydroxides, NiFe‐based oxides, NiFe alloys, and NiFe‐based nonoxides. This review briefly introduces the advanced NiFe‐based OER materials and their corresponding reaction mechanisms. Finally, the challenges inherent to and possible strategies for producing extraordinary NiFe‐based electrocatalysts are discussed.
716 mV Open‐Circuit Voltage with Fully Screen‐Printed p‐Type Back Junction Solar Cells Featuring an Aluminum Front Grid and a Passivating Polysilicon on Oxide Contact at the Rear Side
Authors: Min Byungsul , Wehmeier Nadine , Brendemuehl Till , Haase Felix , Larionova Yevgeniya , Nasebandt Lasse , Schulte-Huxel Henning , Peibst Robby , Brendel Rolf
Published: November 2020

This article reports the recent progress of p‐type back junction solar cells featuring an aluminum front grid and an n+‐type passivating polysilicon on oxide (POLO) contact at the cell rear side. The best cell has an efficiency of 22.6% and an open‐circuit voltage of 716 mV, independently confirmed by Institute for Solar Energy Research Hamelin (ISFH) CalTeC. The cell area is 244.5 cm2. The increase in the SiNx capping layer thickness at the cell rear side reduces the deterioration of passivation quality of the POLO contact by screen‐printed silver. This increases the open‐circuit voltage by 22 mV compared with cells with a thinner nitride layer thickness. The investigation with scanning electron microscopy shows that the damage of the POLO contacts underneath the screen‐printed metal contacts is avoided by increasing the SiNx capping layer thickness. A contact resistivity of 2 mΩ cm2 is measured using the transfer length method.
Construction and characterization of a zinc‐inducible gene expression vector in fission yeast
Authors: Takahata Shinya , Asanuma Takahiro , Mori Miyuki , Murakami Yota
Published: November 2020

Gene expression vectors are useful and important tools that are commonly used in a variety of experiments, including expression of foreign genes, functional analysis of genes of interest and complementation experiments. In this study, a hybrid promoter, combining the adh1+ upstream activating sequence (UAS) of fission yeast and the GAL10 core promoter of budding yeast, was constructed to enable high level expression depending on the presence of zinc in culture medium for fission yeast. When the hybrid promoter was cloned on the multicopy plasmid, it was fully induced and repressed within 10 h in the presence and absence of zinc, respectively. The kinetics of induction and reduction were similar to those of the endogenous adh1+ mRNA. In contrast, native adh1+ promoter lost its tight repression in zinc‐depleted condition when it was cloned on the plasmid. Because adh1+ UAS‐specific transcription factors have not yet been identified, we identified UAS elements involved in zinc sensing by characterizing this hybrid promoter. We also found that the expression level increased by the TATA box mutation, GATAA, in the presence of zinc.
The large-N limit of the 4d $$ \mathcal{N} $$ = 1 superconformal index
Authors: Cabo-Bizet Alejandro , Cassani Davide , Martelli Dario , Murthy Sameer
Published: November 2020

Abstract

We systematically analyze the large-Nlimit of the superconformal index of$$ \mathcal{N} $$N= 1 superconformal theories having a quiver description. The index of these theories is known in terms of unitary matrix integrals, which we calculate using the recently-developed technique of elliptic extension. This technique allows us to easily evaluate the integral as a sum over saddle points of an effective action in the limit where the rank of the gauge group is infinite. For a generic quiver theory under consideration, we find a special family of saddles whose effective action takes a universal form controlled by the anomaly coefficients of the theory. This family includes the known supersymmetric black hole solution in the holographically dual AdS5theories. We then analyze the index refined by turning on flavor chemical potentials. We show that, for a certain range of chemical potentials, the effective action again takes a universal cubic form that is controlled by the anomaly coefficients of the theory. Finally, we present a large class of solutions to the saddle-point equations which are labelled by group homomorphisms of finite abelian groups of orderNinto the torus.
An explicit construction of the dimension-9 operator basis in the standard model effective field theory
Authors: Liao Yi , Ma Xiao-Dong
Published: November 2020

Abstract

We investigate systematically dimension-9 operators in the standard model effective field theory which contains only standard model fields and respects its gauge symmetry. With the help of the Hilbert series approach to classifying operators according to their lepton and baryon numbers and their field contents, we construct the basis of operators explicitly. We remove redundant operators by employing various kinematic and algebraic relations including integration by parts, equations of motion, Schouten identities, Dirac matrix and Fierz identities, and Bianchi identities. We confirm counting of independent operators by analyzing their flavor symmetry relations. All operators violate lepton or baryon number or both, and are thus non-Hermitian. Including Hermitian conjugated operators there are $$ {\left.384\right|}_{\Delta B=0}^{\Delta L=\pm 2}+{\left.10\right|}_{\Delta B=\pm 2}^{\Delta L=0}+{\left.4\right|}_{\Delta B=\pm 1}^{\Delta L=\pm 3}+{\left.236\right|}_{\Delta B=\pm 1}^{\Delta L=\mp 1} $$

384

Δ
B
=
0

Δ
L
=
±
2

+

10

Δ
B
=
±
2

Δ
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0

+

4

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±
1

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3

+

236

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1

Δ
L
=
∓
1

operators without referring to fermion generations, and $$ {\left.44874\right|}_{\Delta B=0}^{\Delta L=\pm 2}+{\left.2862\right|}_{\Delta B=\pm 2}^{\Delta L=0}+{\left.486\right|}_{\Delta B=\pm 1}^{\Delta L=\pm 3}+{\left.42234\right|}_{\Delta B=\mp 1}^{\Delta L=\pm 1} $$

44874

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=
0

Δ
L
=
±
2

+

2862

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B
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0

+

486

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1

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42234

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=
∓
1

Δ
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=
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operators when three generations of fermions are referred to, where ∆L, ∆B denote the net lepton and baryon numbers of the operators. Our result provides a starting point for consistent phenomenological studies associated with dimension-9 operators.
Proximale osteosynthetisch versorgte Femurfrakturen: Der Versorgungszeitpunkt verzögert sich bei vorbestehender Antikoagulation
Authors: Korbmacher J. G. , Schulze-Raestrup U. , Nowak H. , Smektala R.
Published: November 2020

Hintergrund und Fragestellung

Proximale Femurfrakturen stellen mit ca. 100.000 Betroffenen/Jahr in Deutschland ein häufiges Krankheitsbild dar. Durch eine zeitnahe Versorgung (<24 h) konnte die Mortalität erheblich gesenkt werden. Ziele der Arbeit waren, die Prävalenz der Antikoagulation und hiermit assoziierte Komplikationen bei osteosynthetisch versorgter, proximaler Femurfraktur und deren Impact auf die präoperative Verweildauer zu analysieren und Potenziale zum optimalen perioperativen Gerinnungsmanagements aufzuzeigen.

Material und Methoden

Die Daten der externen vergleichenden Qualitätssicherung Nordrhein-Westfalen für die Jahre 2015 und 2016 wurden ausgewertet. Dabei wurden ausschließlich Fälle analysiert, bei denen eine hüftgelenknahe Femurfraktur osteosynthetisch versorgt wurde. Insgesamt wurden 24.786 Fälle hüftgelenknaher Femurfrakturen in die Studie eingeschlossen.

Ergebnisse

Von den Patienten mit einer antithrombotischen Dauertherapie (ATDT) wurden in der größten Subgruppe mit ASS-Medikation (n = 4005) 17 %, in der zweitgrößten Gruppe mit Vitamin-K-Antagonisten-Einnahme (n = 2157) 44,6 % und in der drittgrößten Gruppe mit Einnahme von direkten oralen Antikoagulanzien (DOAKs, n = 994) 18,2 % verzögert operiert.

Schlussfolgerungen

Das größte Potenzial zur Verkürzung der präoperativen Verweildauer ergibt sich in der Gruppe der Patienten, die ASS (17 % auffällig) oder einen Vitamin-K-Antagonisten (VKA, 44,6 % auffällig) einnehmen. Eine Antagonisierung der Wirkung von VKA lässt sich innerhalb kurzer Zeit durch die Gabe von Prothrombinkomplex (PPSB) erreichen. Auch unter der Einnahme von DOAKs muss das noch gängige Prozedere einer verzögerten operativen Versorgung kritisch hinterfragt werden. Die Etablierung eines Gerinnungsmanagements ist zu fordern. Neben der medizinischen Intervention (Gabe von Antidota) müssen Strukturen geschaffen werden, die eine zeitnahe Versorgung ermöglichen.
Analysis of the machinability when milling AlSi10Mg additively manufactured via laser-based powder bed fusion
Authors: Zimmermann Marco , Müller Daniel , Kirsch Benjamin , Greco Sebastian , Aurich Jan C.
Published: November 2020

Laser-based powder bed fusion (L-PBF) is a promising technology for the production of near net–shaped metallic components. The high surface roughness and the comparatively low-dimensional accuracy of such components, however, usually require a finishing by a subtractive process such as milling or grinding in order to meet the requirements of the application. Materials manufactured via L-PBF are characterized by a unique microstructure and anisotropic material properties. These specific properties could also affect the subtractive processes themselves. In this paper, the effect of L-PBF on the machinability of the aluminum alloy AlSi10Mg is explored when milling. The chips, the process forces, the surface morphology, the microhardness, and the burr formation are analyzed in dependence on the manufacturing parameter settings used for L-PBF and the direction of feed motion of the end mill relative to the build-up direction of the parts. The results are compared with a conventionally cast AlSi10Mg. The analysis shows that L-PBF influences the machinability. Differences between the reference and the L-PBF AlSi10Mg were observed in the chip form, the process forces, the surface morphology, and the burr formation. The initial manufacturing method of the part thus needs to be considered during the design of the finishing process to achieve suitable results.
Error propagation in regional geoid computation using spherical splines, least-squares collocation, and Stokes’s formula
Authors: Ophaug Vegard , Gerlach Christian
Published: November 2020

Current International Association of Geodesy efforts within regional geoid determination include the comparison of different computation methods in the quest for the “1-cm geoid.” Internal (formal) and external (empirical) approaches to evaluate geoid errors exist, and ideally they should agree. Spherical radial base functions using the spline kernel (SK), least-squares collocation (LSC), and Stokes’s formula are three commonly used methods for regional geoid computation. The three methods have been shown to be theoretically equivalent, as well as to numerically agree on the millimeter level in a closed-loop environment using synthetic noise-free data (Ophaug and Gerlach in J Geod 91:1367–1382, 2017.10.1007/s00190-017-1030-1). This companion paper extends the closed-loop method comparison using synthetic data, in that we investigate and compare the formal error propagation using the three methods. We use synthetic uncorrelated and correlated noise regimes, both on the 1-mGal ($$=10^{-5}~{\mathrm {m s}}^{-2}$$=10-5ms-2) level, applied to the input data. The estimated formal errors are validated by comparison with empirical errors, as determined from differences of the noisy geoid solutions to the noise-free solutions. We find that the error propagations of the methods are realistic in both uncorrelated and correlated noise regimes, albeit only when subjected to careful tuning, such as spectral band limitation and signal covariance adaptation. For the SKs, different implementations of the L-curve and generalized cross-validation methods did not provide an optimal regularization parameter. Although the obtained values led to a stabilized numerical system, this was not necessarily equivalent to obtaining the best solution. Using a regularization parameter governed by the agreement between formal and empirical error fields provided a solution of similar quality to the other methods. The errors in the uncorrelated regime are on the level of$$\sim $$∼5 mm and the method agreement within 1 mm, while the errors in the correlated regime are on the level of$$\sim $$∼10 mm, and the method agreement within 5 mm. Stokes’s formula generally gives the smallest error, closely followed by LSC and the SKs. To this effect, we note that error estimates from integration and estimation techniques must be interpreted differently, because the latter also take the signal characteristics into account. The high level of agreement gives us confidence in the applicability and comparability of formal errors resulting from the three methods. Finally, we present the error characteristics of geoid height differences derived from the three methods and discuss them qualitatively in relation to GNSS leveling. If applied to real data, this would permit identification of spatial scales for which height information is preferably derived by spirit leveling or GNSS leveling.
Culinary–medicinal mushrooms: a review of organic compounds and bioelements with antioxidant activity
Authors: Podkowa Adrian , Kryczyk-Poprawa Agata , Opoka Włodzimierz , Muszyńska Bożena
Published: November 2020

There are about 3000 species of mushrooms, which have a high amount of substances that are beneficial to human health, such as antioxidants. It is well known that oxidative stress plays an important role in the etiopathogenesis of many diseases, including cancer, cardiovascular disorders, and diseases of the central nervous system. One way to prevent homeostasis disorders that occur as a result of excessive production of pro-oxidative substances is to include the ingredients having antioxidant properties in the diet. Several compounds, such as those with phenolic and indole derivatives as well as carotenoids and some vitamins, exhibit antioxidant activity. These substances are present in many foods, including mushrooms. In addition, they have certain unique compounds that are not found in other sources (e.g., norbadione A). The present work discusses selected ingredients exhibiting antioxidant activity, which are found in various species of mushrooms as wells as describes the content of these compounds in the extracts obtained from mushrooms using artificial digestive juice.
LITHORISK.COM: the novel version of a software for calculating and visualizing the risk of renal stone
Authors: Marangella Martino , Petrarulo Michele , Vitale Corrado , Daniele Piergiuseppe , Sammartano Silvio
Published: November 2020

Estimation of state of saturation with stone-forming salt represents a reliable tool to assess the overall risk. The available methods are based on computer-assisted ab initio calculations. Our earlier method URSUS was subsequently substituted by Lithorisk®, a software including visualization of risk profiles. Unfortunately, Lithorisk does not adapt to new versions of Windows® and Macintosh® Apple, neither runs on smartphones or tablets. We propose a novel version of the software which can be directly used online on any device equipped by different operating systems. Upon online connection and after registration, the software is ready for unlimited accesses, in either Italian, English or French. After digiting input variables (urea and creatinine also included) in a fixed dashboard, state of saturation is promptly given. In addition to state of saturation (ß) with calcium oxalate, brushite and uric acid, ß struvite and cystine are available. Both input variables and ß results are graphically depicted as green or red horizontal bars to indicate recommended values. The software was implemented with equations allowing to omit sulphate and ammonium excretion for users with difficult access to these measurements. This simplified version, tested for ßCaOx and ßBsh on 100 urine samples showed close correlation with the full version. The software gives a list of total and free concentrations and soluble complex species distribution. Results can be printed or saved as PDF. So, we propose an easily accessible software to estimate state of saturation usable on any operating system and personal device.
Exploitative competition and displacement mediated by eusocial bees: experimental evidence in a wild pollinator community
Authors: Wignall Veronica R. , Brolly Matthew , Uthoff Cassandra , Norton Kala E. , Chipperfield Hannah M. , Balfour Nicholas J. , Ratnieks Francis L. W.
Published: November 2020

Eusocial bees are likely to be ecologically important competitors for floral resources, although competitive effects can be difficult to quantify in wild pollinator communities. To investigate this, we excluded honeybees (HBE treatment), bumblebees (BBE) or both (HB&BBE) from wild-growing patches of bramble,Rubus fruticosusL. agg., flowers in two eight-day field trials at separate locations, with complementary mapping of per-site local floral resource availability. Exclusions increased per-flower volume of nectar and visitation rates of non-excluded bees, compared to control patches with no bee exclusions (CON). There was a large increase in average nectar standing crop volume both at Site 1 (+ 172%) and Site 2 (+ 137%) in HB&BBE patch flowers, and no significant change in HBE or BBE, compared to CON patches. Foraging bee responses to exclusion treatments were more pronounced at Site 2, which may be due to lower local floral resource availability, since this is likely to increase the degree of exploitative competition present. Notably, at Site 2, there was a 447% increase in larger-bodied solitary (non-Apis/Bombus) bees visiting HB&BBE patches, suggesting ecological release from competition. Hoverflies showed no response to bee removals. Numbers of other non-bee insect groups were very small and also showed no clear response to exclusions. Our findings reveal patterns of competitive exclusion between pollinator groups, mediated by resource depletion by eusocial bees. Possible long-term implications of displacement from preferred flowers, particularly where alternative forage is reduced, are discussed.

Significance statement

Understanding patterns of exploitative competition and displacement is necessary for pollinator conservation, particularly for vulnerable or threatened species. In this research, experimental methods reveal underlying patterns of resource competition exerted by eusocial bees in a wild pollinator community. We show that honeybees and bumblebees competitively displace each other and particularly solitary (non-Apis/Bombus) bees from bramble, an important native nectar and pollen source. Effects were stronger where local floral resource availability was identified to be limited. Notably, following experimental exclusion of both honey- and bumblebees from flowers, visitation by solitary bees increased by up to 447%, strongly suggesting ecological release from competition. These results highlight the need for informed landscape management for pollinator wellbeing, including appropriate honeybee stocking densities and improved floral resource availability.