bluuebunny/crossref_metadata_2025 huggingface dataset:
Design, synthesis, characterization, and aging properties of a new end‐capped three‐dimensional high‐refractive index hybrid organic–inorganic polysiloxane
Authors: Legrand Sacha , Kärkkäinen Ari
Published: January 2021

The actual need for hybrid organic–inorganic polysiloxanes is very high due to their importance in optoelectronic applications, especially for the preparation of anti‐ and low‐reflection layers, photopatterned overcoats, flexible hard coats, and glass and metal coatings. However, such three‐dimensional hybrid polysiloxanes have very often a limited shelf life and aged very rapidly. Consequently, this type of polymer may require to be stored at cold temperatures and needs to be dilute in organic solvent to a very low solid content, which are unprofitable conditions for commercialization purposes. Therefore, there is an urgent demand to prepare three‐dimensional polysiloxanes, which are more resistant toward aging processes. Herein, a new hybrid three‐dimensional polysiloxane has been designed and synthesized from three different silane precursors using the sol–gel technology, and characterized using gel permeation chromatography, 1H, 13C, and 29Si nuclear magnetic resonance and MS spectroscopies. One‐fourth of the silanol groups present in the polysiloxane have been protected with chlorotrimethylsilane. The refractive index of the silicon wafer coated with the new polysiloxane was found to be 1.53, which is higher compare to traditional values. Importantly, the new protected three‐dimensional polysiloxane did not age after being stored at T = 40°C for 3 weeks.
Recent advances on graphene microstructure engineering for propellant‐related applications
Authors: Liu Yahao , Zheng Jian , Zhang Xiao , Li Ke , Du Yongqiang , Yu Guibo , Jia Yunfei , Zhang Yu
Published: January 2021

As a special polymeric composite and military‐strategic material, composite solid propellant has attracted extensive attention and efforts to improve its performances. Graphene been regarded as an ideal material to enhance the performances of propellants, because of its excellent physical and chemical properties, such as ultra‐strong strength, large specific surface area, remarkable thermal conductivity, and phenomenal electrical performance. Moreover, the microstructure engineering based on graphene has been demonstrated to reveal effective influences on the composites. Recently, many new advances have been developed in microstructure engineering of graphene for propellant‐related applications. In this article, we first present an overview of the main synthesis methods of graphene. Subsequently, these new advances are reviewed, discussed, and summarized carefully. Finally, the application prospects of microstructure engineering of graphene in the propellant field are proposed.
The stone adze and obsidian assemblage from the Talasiu site, Kingdom of Tonga
Authors: REEPMEYER CHRISTIAN , FERGUSON REDBIRD , VALENTIN FRÉDÉRIQUE , CLARK GEOFFREY R.
Published: January 2021

Typological and geochemical analyses of stone adzes and other stone tools have played a significant role in identifying directionality of colonisation movements in early migratory events in the Western Pacific. In later phases of Polynesian prehistory, stone adzes are important status goods which show substantial spatial and temporal variation. However, there is a debate when standardisation of form and manufacture appeared, whether it can be seen in earliest populations colonising the Pacific or whether it is a later development. We present in this paper a stone adze and obsidian tool assemblage from an early Ancestral Polynesian Society Talasiu site on Tongatapu, Kingdom of Tonga. The site shows a wide variety of adze types; however, if raw material origin is taken into account, emerging standardisation in adze form might be detected. We also show that Tongatapu was strongly connected in a network of interaction to islands to the North, particularly Samoa, suggesting that these islands had permanent populations.
Village‐specific Kula partnerships revealed by obsidian sourcing on Tubetube Island, Papua New Guinea
Authors: SHAW BEN , IRWIN GEOFF , PENGILLEY ALANA , KELLOWAY SARAH
Published: January 2021

The inter‐island Kula exchange network within the Massim region of eastern New Guinea is unique in its complexity, with the historically recorded configuration between the northern islands archaeologically visible between 1350 and 1500 AD (600–450 calBP). The southern islands were incorporated sometime later, and Tubetube Island formed a major hub in this southern extension of the Kula. To assess the timing and extent of Tubetube Islander involvement, excavated obsidian was used as a proxy to assess social connections with other island communities within the ambit of Kula. Forty‐nine pieces from two sites, Lagisuna and Tupwana, spanning the relevant period were chemically characterised using pXRF and determined to have been sourced almost exclusively from western and eastern Fergusson sources, respectively. We argue social connections between communities were village specific. Lagisuna had connections with the West Fergusson source region outside of the ethnographically known Kula network from 1500 to 1650 AD (450–300 calBP). Tupwana had maintained historically recorded kinship connections with important Kula communities on Duau and Dobu in the East Fergusson source region over several generations by at least 1800 AD (150 calBP), and probably intermittently from 1500 to 1650 AD. Our results support an increasingly nuanced model for the past development of Kula exchange.
Determination of zolpidem phenyl‐4‐carboxylic acid and zolpidem 6‐carboxylic acid in hair using gas chromatography–electron ionization–tandem mass spectrometry
Authors: Kwon Nam Hee , Kim Seon Yeong , Suh Sung Ill , Kim Jin Young
Published: January 2021

A gas chromatography–electron ionization–tandem mass spectrometric (GC–EI–MS/MS) method was developed and validated for determination of the major metabolites of zolpidem, zolpidem phenyl‐4‐carboxylic acid (ZPCA) and zolpidem 6‐carboxylic acid (ZCA) in human hair. The sample preparation procedure involves decontamination, mechanical pulverization, incubation, extraction and purification prior to instrumental analysis. The extracts were derivatized using hexafluoroisopropanol and heptafluorobutyric anhydride and analyzed by GC–EI–MS/MS. The linear ranges were 8–100 pg/mg for ZPCA and 16–200 pg/mg for ZCA, with the correlation coefficients >0.997. The limits of detection were 1.8 pg/mg for ZPCA and 1.7 pg/mg for ZCA. The recoveries ranged from 77.6 to 111.7%. The intra‐ and inter‐day precisions were within 16.9 and 11.7%, while intra‐ and inter‐day accuracies were −7.0–8.7 and −2.8–7.8%, respectively. The developed method was applied for the analysis of forensic hair samples obtained from suspected zolpidem abusers and the following concentration ranges were monitored: ZPCA 11.9–35.9 pg/mg and ZCA 16.6–21.8 pg/mg. The method proved to be suitable for picogram‐level determination of ZPCA and ZCA in human hair.
Photoregulation of Gene Expression with Ligand‐Modified Caged siRNAs through Host/Guest Interaction
Authors: Wang Qian , Fan Xinli , Jing Nannan , Zhao Han , Yu Lijia , Tang Xinjing
Published: January 2021

Small interfering RNA (siRNA) can effectively silence target genes through Argonate 2 (Ago2)‐induced RNA interference (RNAi). It is very important to control siRNA activity in both spatial and temporal modes. Among different masking strategies, photocaging can be used to regulate gene expression through light irradiation with spatiotemporal and dose‐dependent resolution. Many different caging strategies and caging groups have been reported for light‐activated siRNA gene silencing. Herein, we describe a novel caging strategy that increases the blocking effect of RISC complex formation/process through host/guest (including ligand/receptor) interactions, thereby enhancing the inhibition of caged siRNA activity until light activation. This strategy can be used as a general approach to design caged siRNAs for the photomodulation of gene silencing of exogenous and endogenous genes.
Strategies for Site‐Specific Labeling of Receptor Proteins on the Surfaces of Living Cells by Using Genetically Encoded Peptide Tags
Authors: Wolf Philipp , Gavins Georgina , Beck‐Sickinger Annette G. , Seitz Oliver
Published: January 2021

Fluorescence microscopy imaging enables receptor proteins to be investigated within their biological context. A key challenge is to site‐specifically incorporate reporter moieties into proteins without interfering with biological functions or cellular networks. Small peptide tags offer the opportunity to combine inducible labeling with small tag sizes that avoid receptor perturbation. Herein, we review the current state of live‐cell labeling of peptide‐tagged cell‐surface proteins. Considering their importance as targets in medicinal chemistry, we focus on membrane receptors such as G protein‐coupled receptors (GPCRs) and receptor tyrosine kinases (RTKs). We discuss peptide tags that i) are subject to enzyme‐mediated modification reactions, ii) guide the complementation of reporter proteins, iii) form coiled‐coil complexes, and iv) interact with metal complexes. Given our own contributions in the field, we place emphasis on peptide‐templated labeling chemistry.
Co‐occurring Congeners Reveal the Position of Enantiomeric Amino Acids in Nonribosomal Peptides
Authors: Pérez‐Victoria Ignacio
Published: January 2021

The absolute configuration of the constituent amino acids in microbial nonribosomal peptides is typically determined by Marfey's method after total hydrolysis of the peptide. A challenge to structure elucidation arises when both d and l enantiomeric configurations of an amino acid are present. Determining the actual position of each amino acid enantiomer within the peptide sequence typically requires laborious approaches based on peptide partial hydrolysis or even total synthesis of the possible diastereomers. Herein, an alternative solution is discussed based on the homogeneous backbone chirality that governs all peptides biosynthesized by a common nonribosomal peptide synthetase. The information on configuration provided by Marfey's analysis of co‐occurring minor congeners can reveal unequivocally the stereochemical sequence of the whole peptide family.
The role of TRIM family proteins in autophagy, pyroptosis, and diabetes mellitus
Authors: Wan Tingting , Li Xiudan , Li Yanbo
Published: January 2021

The ubiquitin‐proteasome system, which is one of the systems for cell protein homeostasis and degradation, happens through the ordered and coordinated action of three types of enzymes, E1 ubiquitin‐activating enzyme, E2 ubiquitin‐carrier enzyme, E3 ubiquitin‐protein ligase. Tripartite motif‐containing (TRIM) family proteins are the richest subfamily of really interesting new gene E3 ubiquitin ligases, which play a critical role not only in many biological processes, including proliferation, apoptosis, pyroptosis, innate immunity, and autophagy, but also many diseases like cancer, diabetes mellitus, and neurodegenerative disease. Increasing evidence suggests that TRIM family proteins play a vital role in modulating autophagy, pyroptosis, and diabetes mellitus. The aim of this review is to discuss the role of TRIM proteins in the regulation of autophagy, pyroptosis, diabetes mellitus, and diabetic complications.
Endovascular snare technique to facilitate delivery of self‐expanding valve during transcatheter aortic valve‐in‐valve replacement in angulated aortas: A case series
Authors: Rohm Charlene L. , Farhat Salman , Al‐Hijji Mohammed , Goel Kashish , Greason Kevin , Gulati Rajiv , el Sabbagh Abdallah
Published: January 2021

Background

Transcatheter aortic valve‐in‐valve replacement (ViV) has been widely accepted as a less invasive alternative to treat failed aortic surgical or transcatheter bioprosthetic valves. Angulated aortas present an additional challenge, particularly when using self‐expanding transcatheter heart valves (SE‐THV).

Methods

Two patients with failed surgical bioprosthetic aortic valves and one patient with a failed transcatheter bioprosthetic aortic valve underwent transcatheter aortic ViV using SE‐THV. All were deemed high‐risk for surgical aortic valve replacement by a heart team. All three patients had initial failed SE‐THV delivery using a conventional approach with subsequent successful delivery using the endovascular snare technique.

Results

In Cases 1 and 2, the SE‐THV was biased towards the greater curve of the angulated aorta and behind the outer frame of the bioprosthetic valve frame. An endovascular snare was deployed through a secondary left femoral artery access, and the valve delivery system was advanced through the snare in the ascending aorta. The snare was tightened around the SE‐THV capsule proximal to the hat‐marker, allowing deflection of the SE‐THV and successful delivery. In Case 3, the SE‐THV interacted with the tall frame of a failed SE‐THV. A snare via the left femoral artery was deployed in the descending artery. The SE‐THV was advanced through the snare, and both the snare and SE‐THV were advanced together to the ascending aorta where the SE‐THV was deflected and successfully delivered.

Conclusions

The endovascular snare technique is a feasible option for successful delivery of SE‐THV during transcatheter aortic ViV in failed transcatheter or surgical bioprosthetic valves in angulated aortas.
Transcatheter Fontan completion using novel balloon and stent system
Authors: Aregullin E. Oliver , Mohammad Nijres Bassel , Al‐Khatib Yasser , Vettukattil Joseph
Published: January 2021

Despite advances in percutaneous interventions, transcatheter Fontan completion remains experimental and performed only in select cases. Non‐surgical Fontan completion requires surgical preconditioning at an earlier stage of palliation. We describe transcatheter Fontan completion in a 15‐year‐old male with previously failed surgical Fontan palliation without surgical preconditioning.
Novel strategy for ostial left anterior descending artery acute myocardial infarction: Combined treatment with directional coronary atherectomy followed by drug‐coated balloon angioplasty
Authors: Yamamoto Hiroyuki , Sawada Takahiro , Takaya Tomofumi , Kawai Hiroya , Yasaka Yoshinori
Published: January 2021

A 69‐year‐old female diagnosed with ostial left anterior descending artery acute myocardial infarction underwent percutaneous coronary intervention using combined directional coronary atherectomy followed by drug‐coated balloon angioplasty. This report highlights a novel management strategy with no permanent scaffold left in the coronary artery.
Conflicting clinical and radiological management decisions
Authors: Zaalouk Tamer Mohamed , Bitar Zouheir Ibrahim , Maadarani Ossama Sajeh
Published: January 2021

Gliosis with hemorrhagic transformation is a late reported complication of stroke. Sometimes there is a big discrepancy between clinical and radiological diagnosis, and clinical decisions must be multi‐aspect decisions and not dependent on a single discrepant investigation result.
A call for individualized evacuation strategies for floods: A case report of secondary surgical site infection in a postsurgery breast cancer patient in Fukushima, Japan, following Typhoon Hagibis in 2019
Authors: Ozaki Akihiko , Kanemoto Yoshiaki , Wada Masahiro , Kurokawa Tomohiro , Kawamoto Ayumu , Sawano Toyoaki , Bhandari Divya , Tsubokura Masaharu , Tanimoto Tetsuya , Ejiri Tomozo , Kanzaki Norio
Published: January 2021

Recognition of Individual and environmental risks is crucial to alleviate damage inflicted by disasters. In particular, an awareness of floods and their health risks in patients’ residences is important for patients and their healthcare professionals.
A case of cardiopulmonary arrest due to left ventricular free wall rupture successfully treated with sutureless repair supported by venoarterial extracorporeal membrane oxygenation
Authors: Suzuki Ginga , Ichibayashi Ryo , Yamamoto Saki , Serizawa Hibiki , Kawada Kota , Kameda Toru , Nakamichi Yoshimi , Watanabe Masayuki , Okuma Shinnosuke , Honda Mitsuru
Published: January 2021

Extracorporeal membrane oxygenation for cardiopulmonary arrest due to left ventricular free wall rupture is considered effective, because it enables rapid cardiopulmonary support and introduction of targeted temperature management.
Outside the box—Surgery for aggressive plasmacytoma in scar
Authors: Fliss Ehud , Zaretski Arik , Cohen Yael , Shapira Yuval , Gur Eyal , Yanko Ravit
Published: January 2021

This report introduces the concept of large‐scale surgery and reconstruction when all other medical means of treatment have failed. In select cases, this may act as a mode of buying time and allowing the patient to receive second‐ or third‐line treatments.
Overlap between EBV‐positive diffuse large B‐cell lymphoma, NOS, in a young patient and angioimmunoblastic T‐cell lymphoma: A diagnostic pitfall
Authors: Kim Chae Hwa , Ghaffaripour Taban , Zhou Yi , Chapman Jennifer R.
Published: January 2021

There may be significant histopathologic overlap between EBV‐positive DLBCL, NOS, and other diagnoses including angioimmunoblastic T‐cell lymphoma (AITL). Resolution of this differential diagnosis may be particularly challenging and require extensive investigation of clinicopathologic features.
Fighting diagnostic confirmation bias: Cystic fibrosis, allergic bronchopulmonary aspergillus, or both?
Authors: Choi Patricia , Bauler Laura , Gregoire‐Bottex M. Myrtha
Published: January 2021

As diagnostic algorithms for cystic fibrosis (CF) continue to evolve, education of general practitioners is essential to prevent delayed diagnosis of CF and allow prompt referral to CF centers. For patients suffering from allergic bronchopulmonary aspergillosis (ABPA), CF should be at the top of the differential diagnosis.
Mass Transfer Behavior of a Rotating Hexagonal Cylinder Reactor Suitable for Water Pollution Control
Authors: Saad Eldin Mohamed H. , Nosier Shaban A. , Abdel-Aziz Mohamed H. , Hussein Mohamed , Sedahmed Gomaa H.
Published: January 2021

Rates of mass transfer at a rotating cylinder of the hexagonal cross section were measured by the limiting current method. A drag‐reducing polymer diminished the speed of mass transfer depending on polymer quantity and rotation speediness. Rotating hexagonal cylinders provided higher degrees of mass transfer than circular rotating cylinders under identical conditions. The performance of rotating hexagonal cylinders in eliminating Cu2+ from dilute liquids was examined and found to be satisfactory. Besides the diffusion‐controlled electrochemical reactions like anodic oxidation of organic contaminants, the reactor can remove organic pollutants via catalytic diffusion‐controlled reactions. The high degree of heat transfer from the cylinder to the liquid would prevent possible hot spots, catalyst deactivation, and decomposition of products.
Enantioselective conjugate addition of pyrazolones to nitroalkenes catalyzed by chiral squaramide organocatalyst
Authors: Aydin Alime Ebru , Culha Selda
Published: January 2021

The chiral squaramide catalysts (8–15) were synthesized, and their catalytic efficiency in the enantioselective conjugate addition of pyrazolones to nitroalkenes was described. This protocol provides excellent chemical yields (up to 93%) of chiral 5‐methyl‐4‐(2‐nitro‐1‐arylethyl)pyrazol‐3‐ol derivatives with high enantioselectivities (up to 97% ee).
Effect of zero‐valent iron nanoparticles on the remediation of a clayish soil contaminated with γ‐hexachlorocyclohexane (lindane) in a bioelectrochemical slurry reactor
Authors: Mar‐Pineda Catherine G. , Poggi‐Varaldo Héctor M. , Ponce‐Noyola M. Teresa , Estrada‐Bárcenas Daniel A. , Ríos‐Leal Elvira , Esparza‐García Fernando J. , Galíndez‐Mayer Juvencio , Rinderknecht‐Seijas Noemí F.
Published: January 2021

In this research we evaluated the effect of adding zero‐valent iron nanoparticles (ZVI‐NP) to a complete mix bioelectrochemical slurry reactors (BESR) on the remediation of a clayish soil with a high content of organic matter, contaminated with lindane. Five BESR were loaded with a clayish polluted soil (100 mg lindane/kgds), known concentrations of ZVI‐NP, liquid medium, and sulphate‐reducing inoculum to give a 33% w/v soil concentration. A one‐factor experimental design was used, where the effect of nanoparticles concentration [NP] on lindane removal efficiency (ηlin) and other response variables were evaluated. The [NP] levels were 0.0 (background control with electrical connection, BCWC), 2.5 (Exp1), 5.0 (Exp2), and 7.5 gNP/kgds (Exp3). Maximum ηlin (95%) was attained in Exp2 (5 gNP/kgds). Beyond this level the ηlin slightly decreased (Exp3 with 85% ηlin.) Approximately 40%‐57% of lindane was removed in the first 24 hours during a rapid kinetics phase. No metabolites of lindane degradation were detected after 30 days of operation in all the BESR. Energy production increased with [NP]; Exp3 generated 4.3 MJ/tonneds at 30 days, whereas the other treatments produced energy between 1.6 MJ/tonneds‐1.2 MJ/tonneds. Bioelectrical energy could partially offset the requirements of BESR mixing energy. Overall performance evaluation using an ad hoc multicriteria framework indicated that BESR followed the order Exp2 > Exp3 > Exp1 ~ BCWC > ABCWOC (abiotic control without electrical connection). There was a significant, positive effect of the combined BESR and ZVI‐NP technology for the remediation of heavy soils contaminated with lindane.
Bridging from the Sequence to Architecture: Graft Copolymers Engineering via Successive Latent Monomer and Grafting‐from Strategies†
Authors: Zhang Yajie , Cao Xiaohuan , Gao Yang , Xie Yujie , Huang Zhihao , Zhang Zhengbiao , Zhu Xiulin
Published: January 2021

Main observation and conclusion

The on‐demand building copolymer structures, from sequence to architecture, is crucial in understanding the relation between polymer structure and property, meanwhile motivating the innovation of polymer hierarchy. However, the challenge is conspicuous for complicated polymer structures from inherently intricate polymerization. In this work, copolymers with tailored grafting density and distributions were achieved using successive latent monomer and grafting‐from strategies. The hydroxyl group functionalized furan/maleimide adduct (FMOH) was selected as the latent monomer for RAFT polymerization of an array of copolymers with tailored localization of hydroxyl group along the main chain. The hydroxyl group further initiated the ring opening polymerization (ROP) of L‐lactide or ε‐caprolactone, resulting in a library of multicomponent copolymers via grafting‐from strategy. The initiating efficiency reached to ~100% with variable molecular weight (21300—58600 Da) and narrow distributions (ÐM < 1.25), indicating that such graft copolymers possessed controlled density and distribution of side chains as its linear template. The investigation on thermal properties of the well‐defined graft copolymers implied that the precise tailoring over copolymer structures at the molecule level could lead to tunable chemical/physical properties. This work bridged polymer from sequence to architecture, unveiled a new method in creating graft copolymers with programmable structures and provided the insight into the structure/property relationship.
In Situ Characterization of Transformations in Nanoscale Layered Metal Chalcogenide Materials: A Review
Authors: Kondekar Neha , Shetty Pralav P. , Wright Salem C. , McDowell Matthew T.
Published: January 2021

Layered metal chalcogenide materials, such as MoS2 and Bi2Te3, have found important applications as 2D materials in emerging electronic devices. To create nanoscale layered chalcogenide materials with precisely controlled structures and properties, it is critical to understand and control how they evolve and transform under various conditions. This Minireview presents an overview of recent research focused on using in situ characterization to understand the atomic‐scale details of transformations during growth, under exposure to reactive chemical and thermal environments, and on interfacing with other materials. These efforts have used techniques including in situ transmission electron microscopy (TEM), X‐ray spectroscopy, and optical methods to understand nanoscale transformations. These in situ studies have provided a substantially improved understanding of transformation mechanisms in layered chalcogenide materials, which is an important step toward the use of these interesting materials in a variety of electronic and electrochemical devices.
Membrane Fusion Models for Bioapplications
Authors: Mazur Federico , Chandrawati Rona
Published: January 2021

Membrane fusion is a highly evolved and significant physiological process involving the mixing of two initially distinct lipid bilayer membranes. It is concerned with communication between and within cells and plays a key role in various processes such as exocytosis, endocytosis, fertilization, viral infection, and carcinogenesis. Due to its significant role, artificial model systems using lipid membranes have been developed over the last few decades which study the membrane fusion mechanism on a molecular level. More recently, this field of research has shifted its attention towards the use of these developed models for a diverse range of biomolecular and biomedical applications. This review will focus on current applications which stem from these models including drug delivery, sensing, protocell proliferation, and others. Our opinions on the future advancements of this field will also be included.
B, N Co‐doped Nanocarbon Derived In Situ from Nanoboron Carbide as Electrocatalyst for Oxygen Reduction Reaction
Authors: Zhou Shuyu , Zang Jianbing , Li Wei , Tian Pengfei , Gao Hongwei , Song Shiwei , Tian Xueqing , Wang Yanhui
Published: January 2021

Heteroatom‐doped metal free carbon materials, especially boron and nitrogen co‐doped carbons have been widely researched as promising oxygen reduction electrocatalysts because of their low cost, high activity and environmental friendliness. However, B, N‐doped carbon electrocatalysts are usually prepared at high temperature and accompanied by the formation of B−N bonds resulting in the inactivation of the active sites. This paper proposed a strategy for synthesizing B and N co‐doped carbons for oxygen reduction reaction in‐situ derived from nano‐boron carbide by one‐step heat treatment at low temperature. This strategy can produce B‐ and N‐doped active sites while avoiding formation of B−N bonds, allowing electrocatalysts to exhibit excellent catalytic activities (Eonset=0.93 V, E1/2=0.79 V) and better stability (current density remained 93.3% after 12,000 s) comparable to commercial Pt/C (20 wt%). New ideas were provided by this work to massively produce the B and N co‐doped carbon electrocatalysts candidates for ORR.
Two Polyoxometalate‐Based Hybrid Compounds Modified by Iron Schiff Base Complexes: Syntheses, Crystal structures, Cyclic Voltametric Studies and Nonlinear Optical Properties
Authors: Wang Ji‐Lei , Yang Mu‐Xiu , Zhu Yu‐Xuan , Cao Jia‐Peng , Du Ze‐Yu , Li Jia‐Nian , Liu Xiao‐Mei , Xu Yan
Published: January 2021

Two new polyoxometalate (POM)‐based hybrid compounds modified by a Schiff base, [Fe(DAPSC)(H2O)2]2[HPMo2VMo10VIO40] ⋅ 5H2O (1) and [Fe(DAPSC)(H2O)]2[HPV3IVMo4VMo7VIO42] ⋅ 6H2O (2), (DAPSC=2,6‐diacetylpyridine bis‐(semicarbazone)), have been successfully constructed from typical Keggin POMs, iron ions, and DAPSC ligands under hydrothermal condition. Structural analysis demonstrates that the Fe‐Schiff base ligand units are free from polyacid anions in compound 1. While in compound 2, the Fe‐Schiff base ligand units are bridged with polyacid anions via Fe−O bonds to emerge a stable double‐supported skeleton. Noticeably, owing to the introduction of vanadium in H5PMo10V2O40 ⋅ 32.5H2O, a divanadium‐capped configuration is shaped in compound 2. Besides, the third‐order nonlinear optical (NLO) properties of two compounds were explored. It should be noted that both compounds 1 and 2 have two‐photon absorption properties, which indicates that the two compounds are potential nonlinear optical materials.
Light‐Induced Electron Transfer in Manganese(V)–Oxo Corroles
Authors: Wang Li‐Li , Wan Bei , Lai Shu‐Hui , Weng Lin‐Fang , Liu Hai‐Yang , Wang Hui
Published: January 2021

Electron and proton transfer reactions are essential elements in water oxidation by the oxygen‐evolving complex of photosystem II. To date manganese(V)–oxo corrole has successfully mimicked the oxygen evolution reaction. We report here ultrafast intramolecular electron transfer (ET) in corrole manganese (Mn) complexes. With femtosecond spectroscopy, the evolutions of transient absorption spectra of three kinds of Mn(V)–oxo corroles were measured. A ∼0.17 ps ET process has been observed in (OHF10C)MnV(O) after photoexcitation at 400 nm, which is absent for (F15C)MnV(O) and (F10C)MnV(O). The back ET is different from that of Mn(III) corrole ((OHF10C)MnIII), being a ∼12.3 ps ET followed by a very long ground‐state recovery. The mechanism of the ET observed in (OHF10C)MnV(O) has been discussed. The result reveals that the natural O−O bond formation may include ultrafast ET among the calcium‐ligated hydroxide, Mn(V), and the oxygen bound to the metal ion.
Gingival cell growth with antiresorptive treatment combined with corticosteroids or antiestrogen
Authors: Ekholm Heidi M. , Löyttyniemi Eliisa , Soukka Tero , Rautava Jaana
Published: January 2021

Objectives

Antiresorptive treatment has been shown to impair mucosal cell proliferation, migration, and viability. However, in the clinic, antiresorptives are often used in combination with other drugs. We studied the effect of antiresorptives combined with a corticosteroid or antiestrogen on oral mucosal keratinocytes and fibroblasts.

Material and methods

Human gingival keratinocyte and fibroblast cell lines were exposed to bisphosphonates (BPs) and denosumab in different concentrations and durations together with an antiestrogen or corticosteroid. Changes in cell viability, proliferation and migration after exposures were measured. Data were evaluated with hierarchical linear mixed model for repeated measurements.

Results

Bisphosphonate exposure suppressed keratinocyte and fibroblast cell viability, proliferation, and migration in a time‐dependent manner. Combining a corticosteroid or antiestrogen with BPs further increased this negative effect. Denosumab alone had a mild positive effect on keratinocyte and fibroblast growth. When denosumab was combined with a corticosteroid or antiestrogen, cell growth was suppressed.

Conclusions

Our results show that coexisting medications may increase the negative impact of BPs or denosumab on oral mucosal cells.
Self‐sustained solitary waves in a tunnel diode oscillator lattice and their applications in frequency division
Authors: Narahara Koichi
Published: January 2021

Self‐sustained solitary waves, which propagate in a one‐dimensional lattice of tunnel diode (TD) oscillators, can be effectively applied to frequency division. In this work, it is experimentally observed that the properties of a solitary wave strongly suggest that it is the discretized counterpart of the homoclinic pulse predicted in a quasi‐continuous model of a TD oscillator lattice. Generally, these self‐sustained waves annihilate during a head‐on collision. Owing to this phenomenon, a TD oscillator lattice acts as an efficient frequency divider through its simple connection to an ordinary LC ladder circuit. In this work, both the pair annihilation of pulses and a 2:1 frequency division ratio are successfully observed experimentally.
An interharmonic dual switching frequency modulation strategy for impedance network inverters
Authors: Mohammadi Mohammad , Moghani Javad S. , Mattavelli Paolo , Khoshsaadat Alireza , Mahdi Asghari Mohammad , Milimonfared Jafar
Published: January 2021

Recently, a novel dual switching frequency modulation (DFM) has been proposed for impedance network inverters (INIs). The proposed approach allows the INIs to be designed optimally in size and efficiency, for motor drive applications. Moreover, DFM provides the possibility of operation with unity modulation index. However, DFM requires a high‐frequency ratio between pulse‐width modulation (PWM) and sinusoidal PWM (SPWM) switching frequencies. This paper proposes an improved modulation strategy to overcome this issue. The modulation called interharmonic dual frequency modulation (IDFM) utilizes the interharmonic areas of a conventional sinusoidal PWM to implement DFM. The proposed approach gives a low total harmonic distortion (THD) output voltage without increasing the frequency ratio of PWM and SPWM. IDFM provides the possibility of selecting a wide range of frequencies for both switching modulations. The approach is explained theoretically, compared with other switching strategies, and also the simulation and experimental results are used to validate its performance.
Iron deficiency promotes aortic medial degeneration via destructing cytoskeleton of vascular smooth muscle cells
Authors: Li Bowen , Wang Zhiwei , Hong Junmou , Che Yanjia , Chen Ruoshi , Hu Zhipeng , Hu Xiaoping , Wu Qi , Hu Junxia , Zhang Min
Published: January 2021

Background

Aortic dissection (AD) and aortic aneurysm (AA) are critical illnesses with an unclear pathogenetic mechanism that seriously threaten human life. Aortic medial degeneration (AMD) is the main pathological feature of AD and AA. Diseases of iron metabolism can cause a variety of physiological dysfunctions. In this study, we aimed to clarify the state of iron metabolism in patients with AD and AA, and to explore the effect of iron metabolism on AMD.

Methods

A total of 200 patients with AD or AA, and 60 patients with hypertension were included in the study. Blood samples were drawn immediately when patients were admitted to the hospital. Aortic specimens from patients with Stanford type A AD were obtained at the time of surgery. The status of iron metabolism in the circulation and the aortic wall was analyzed. In addition, apolipoprotein E knockout mice were fed chow with a different iron content, and angiotensin II (Ang II) was used to induce AMD. Furthermore, transferrin receptor 1 knockout (TFR1−/−) mice were used to study the effects of iron deficiency (ID) on aortic development, to observe the effects of different iron metabolism status on the formation of AMD in mice, and to explore the cytoskeleton of vascular smooth muscle cells (VSMCs) under different iron metabolism.

Results

Patients with AMD were iron deficient. ID is associated with the development of AMD in hypertensive patients. Iron‐deficient feeding combined with Ang II pumping promoted the formation of AMD and significantly shortened the survival time of mice. ID significantly impaired the cytoskeleton of VSMCs.

Conclusions

: Our results highlighted that ID was associated with the formation of AMD in patients with hypertension. In this study, we identified a novel mechanism behind VSMCs dysfunction that was induced by ID, thereby suggesting iron homeostasis as a future precaution in patients with hypertension based on its important role in the maintenance of VSMC function.
Utility of the Milan system for reporting salivary gland cytopathology: A retrospective 5 years study
Authors: Chirmade Jyoti , Kothari Kanchan , Naik Leena , Agnihotri Mona
Published: January 2021

Background

Fine‐needle aspiration cytology (FNAC) is an established technique for preoperative diagnosis of salivary gland lesions; however, lack of a uniform reporting system has been a handicap. The main aims of this study were to evaluate the utility of the – “The Milan System for Reporting Salivary Gland Cytopathology” (MSRSGC) and ascertain the risk of malignancy (ROM) for each category.

Methods

All salivary gland FNACs over 5 years (January 2014‐December 2018) were reviewed and assigned a diagnostic category from the MSRSGC. Clinical data were taken from Cytology records. Cytodiagnosis was correlated with histopathology wherever available and ROM was calculated.

Results

A total of 120 salivary gland FNACs were studied. Age ranged between 5 and 85 years, male:female ratio was 2:1 and parotid was the commonest gland aspirated. Cases were reclassified as I non‐diagnostic (2.5%), II non‐neoplastic (15%), III atypia of uncertain significance‐AUS (1.7%), IV A neoplasm benign (50%), IV B neoplasm of uncertain malignant potential (12.5%), V suspicious for malignancy (5%), and VI malignant (13.3%). Follow‐up was available in 70 (58.3%) cases. The sensitivity, specificity, negative predictive value, and positive predictive value were 92.3%, 100%, 100%, and 98.27% respectively. ROM was non‐neoplastic (0%), AUS (50%), neoplasm benign (0%), neoplasm of uncertain malignant potential (28.6%), suspicious for malignancy (100%), and malignant (100%).

Conclusion

Salivary gland FNAC is a reliable diagnostic tool and the “Milan system” will further increase FNA reliability, help risk stratification, and improve patient care.
Micro RNAs in Tfh regulation: Small molecules with a big impact
Authors: Basto Afonso P. , Graca Luis
Published: January 2021

The germinal center (GC) reactions are critical for the production of high‐affinity antibodies that comprise the protective humoral response elicited by infection or vaccination. GCs are initiated through the interaction of B cells with T follicular helper (Tfh) cells. While the transcriptional regulation of Tfh differentiation has been studied in great detail, the impact of micro RNAs (miRNAs) on Tfh development and stability has been harder to address. It was previously shown that a complete deletion of miRNAs biogenesis prevents Tfh differentiation. In this issue of the European Journal of Immunology [Eur. J. Immunol. 2021. 51: 408‐413], Zeiträg et al. use an inducible gene deletion approach to reveal that miRNAs are also required for the maintenance of Tfh cells induced following viral infection in mice. These results provide new clues to the regulation of GC responses through Tfh and T follicular regulatory cells.
Heating and convection associated with alkaline electrophoresis
Authors: Khizhnyak Evgenii P. , Sirota Nikolay P. , Kuznetsova Elena A. , Khizhnyak Larisa N. , Sirota Tatyana V.
Published: January 2021

Alkaline version of the single‐cell gel electrophoresis (Comet assay) is widely used in toxicological, environmental, and monitoring studies to assess the DNA damage levels in individual cells. The change in the temperature of the electrophoretic solution is one of the reasons leading to interlaboratory variation of Comet assay results. In this work, changes of surface temperature of the solution during electrophoresis were studied using technique of real‐time thermal imaging. It has been found that the electrophoresis is accompanied by nonuniform temperature rise in different areas of the electrophoretic chamber. The maximum of heating was observed in the central region of the chamber, where temperature increased by an average of 7°C. The minimum temperature rise in other parts of the chamber was about 5°C. After removing the solution, the temperature on the surface of slides was higher than that on the surface of the solution. We believe that (1) nonuniform heating of the electrophoretic solution and convection could be the reasons responsible for the variability of results both in inter‐ and intralaboratory studies; (2) the spatial distribution of heating of the solution depends on the size and configuration of the electrophoretic chambers used.
Integrated Process Control‐Power Management System Design and Flight Performance Tests for Fuel Cell Powered Mini‐Unmanned Aerial Vehicle
Authors: Erdör Türk Betül , Sarul Mustafa Hadi , Çengelci Ekrem , İyigün Karadağ Çiğdem , Boyacı San Fatma Gül , Kılıç Murat , Okumuş Emin , Yazıcı Suha
Published: January 2021

Unmanned aerial vehicles (UAVs) powered by electric motors are in an advantageous position because of their properties, such as low noise and thermal footprint, high efficiency, and zero emissions. Lithium‐based batteries have restrictive factors for flight duration due to its low energy density, difficult, and expensive charging methods. It is aimed to extend flight duration of a battery powered mini‐type UAV with a combined system, which includes a 200 W polymer electrolyte membrane (PEM) fuel cell, a hydrogen generation system based on in situ hydrolysis of sodium borohydride, a hybrid power management system consisting of fuel cell and battery, and an embedded control system. It is observed that a fuel cell‐based energy system is able to extend endurance by twofolds compared with an only battery powered system. This is the first study in the literature that investigates the flight duration of UAVs in battery versus fuel cell according to actual flight data.
Molten‐Salt Technology Application for the Synthesis of Photocatalytic Materials
Authors: Luo Laiyu , Wang Siyu , Wang Hong , Tian Chungui , Jiang Baojiang
Published: January 2021

Most of the photocatalytic materials are prepared by wet chemical methods and calcination methods. These preparation methods usually have the problems of slow reaction speed and low crystallinity of products, which seriously restrict the development of photocatalytic technology. Molten salt method (MSM) has attracted much attention of researchers because of its unique advantages in optimizing the synthesis route of photocatalyst. Herein, the application of molten salt technology in the preparation of photocatalytic materials in recent years is summarized. The advantages of MSM in photocatalytic synthesis, such as promoting crystallization, adjusting morphology, accelerating the construction of heterostructure, stabilizing single atom, doping auxiliary elements and adjusting defect position, are also discussed in detail. It is indicated that MSM has important application potential in the preparation of photocatalytic materials. Meanwhile, the research achievements and existing problems of MSM are summarized, and suggestions for further application of MSM in photocatalyst's preparation are put forward.
A Novel Metal–Organic Framework Intermediated Synthesis of Heterogeneous CoS2/CoS Porous Nanosheets for Enhanced Oxygen Evolution Reaction
Authors: Hu Xiaoyue , Tan Pengfei , Dong Rui , Jiang Min , Lu Lili , Wang Yuan , Liu Hongqin , Liu Yong , Xie Jianping , Pan Jun
Published: January 2021

Designing and constructing transition metal sulfides (TMSs) as oxygen evolution reaction (OER) electrocatalysts has been attracting increasing attention. Interface engineering can effectively modify the active sites and promote electron transfer, resulting in improvement of electrocatalytic performance. Here, freestanding heterogeneous CoS2/CoS nanosheets are prepared via a simple one‐step sintering process from a kind of novel hierarchical tremella‐like metal–organic framework (MOF). The formation mechanism of the unique MOF and the heterojunctions between CoS2 and CoS is analyzed. Consequently, the prepared cost‐effective OER electrocatalyst achieves satisfying electrocatalytic efficiencies with a diminutive overpotential of 269 mV at 10 mA cm−2 current density, a small Tafel slope of 52 mV dec−1, and good stability in alkaline solution comparable to RuO2 counterparts. This work opens up a new method for constructing 2D electrocatalysts containing catalytic interfaces with boosted OER performance.
In Situ Growth of CoSe2 Coated in Porous Carbon Layers as Anode for Efficient Sodium‐Ion Batteries
Authors: Ge Huaiyun , Fan Siwei , Liu Jianyu , Li Guangda
Published: January 2021

A novel composite material of CoSe2/N‐doped carbon box (CoSe2/NC) is successfully synthesized using zeolitic imidazolate frameworks‐67 as the sacrificial templates through a simple two‐step calcine process. The CoSe2 nanoparticles are encapsulated in N‐doped carbon layers, which can seriously avoid agglomeration. When used CoSe2/NC as anode materials for sodium‐ion batteries (SIBs), it exhibits an excellent high reversible specific capacity and a superior cycling stability of 390.2 mA h g−1 at 5 A g−1 over 4000 cycles. The excellent performance of CoSe2/NC can be attributed to cooperation of CoSe2 nanoparticles and N‐doped carbon layers. Carbon layers coated on the surface of CoSe2 nanoparticles not only improve a well conductivity to facilitate the charge transfer, but also buffer the structure to expand during the Na+ insertion/extraction process. Furthermore, this novel porous structure provides more active sites and increases contact areas between the materials and the electrolyte, thus increasing the specific capacity and cycle stability. This work provides a possibility of anode materials for SIBs with excellent electrochemistry performance.
ZnO‐Based Conversion/Alloying Negative Electrodes for Lithium‐Ion Batteries: Impact of Mixing Intimacy
Authors: Asenbauer Jakob , Passerini Stefano , Bresser Dominic
Published: January 2021

Conversion/alloying materials, such as transition metal (TM)‐doped ZnO, are showing superior performance over pure ZnO due to the presence of the TM, enabling the reversible formation of Li2O due to the enhanced electronic conductivity within the single particle once being reduced to the metallic state upon lithiation. Herein, the impact of introducing Co as representative TM at the atomic level in ZnO compared with mixtures of nano‐ and microsized CoO and ZnO is investigated. While even rather simple mixtures provide higher capacities than pure ZnO, an intimate mixing of nanoparticulate CoO and ZnO leads to a further increase due to the more homogeneous dispersion of Co. Nonetheless, the “atomic mixing” via doping still provides the highest capacities—for both nano‐ and microparticles, thus highlighting the importance of the very fine distribution of Co (and generally the TM) for realizing effective electron conduction pathways to enable the reversible formation of Li2O.
Seismic robustness of self‐centering braced frames suffering tendon failure
Authors: Ping Yiwei , Fang Cheng , Chen Yiyi , Yam Michael C. H.
Published: January 2021

This paper comprehensively discusses the behavior and failure risk of self‐centering braced frames suffering tendon fracture. The fundamental mechanism of tendon failure in self‐centering braces (SCBs) is first introduced, followed by the design and analysis of a series of prototype buildings with different tendon materials and brace configurations. Assuming a normal distribution of tendon fracture strain, the dynamic behavior of the frames is then assessed by a suite of ground motion records, covering both far‐field and near‐fault ones. The collapse and residual deformation fragilities of the frames are further evaluated, and the study ends with a risk assessment considering a 50‐year service period. Among other findings, the study indicates that tendon fracture tends to increase the peak interstory drift, especially for the structure with smaller tendon fracture strains. Tendon fracture also compromises the self‐centering capability significantly, although there is no obvious statistical correlation between tendon fracture and the peak floor acceleration. The probability of collapse and that of exceedance of certain residual drift both increase evidently when tendon fracture is considered. The failure probabilities are closely related to the available deformability of the SCBs, where dual‐core SCBs show less sensitivity to tendon fracture. The probability of collapse of the considered frames over 50 years of service increases from 1.25‐2.12% to 3.58‐6.52% when tendon fracture is considered. Considering a residual drift threshold of 0.5%, the probability of exceedance of the same structures over the same life span increases from 1.78‐3.54% to 5.46‐9.71%.