bluuebunny/crossref_metadata_2025 huggingface dataset:
The impact of vascular risk factors on the thickness and volume of the choroid in AMD patients
Authors: Krytkowska Elżbieta , Grabowicz Aleksandra , Mozolewska-Piotrowska Katarzyna , Ulańczyk Zofia , Safranow Krzysztof , Machalińska Anna
Published: July 2021

Disturbances in choroidal microcirculation may lead to the onset and progression of age-related macular degeneration (AMD). We aimed to assess changes in the choroidal volume and thickness in the macular region in AMD eyes and to investigate whether coexisting vascular risk factors alter choroidal status. We enrolled 354 AMD patients (175 dry, 179 wet AMD) and 121 healthy controls. All participants underwent a complete ophthalmologic examination and assessment of choroidal thickness and volume. A multivariate analysis adjusted for age, sex, and smoking status revealed that wet AMD was an independent factor associated with higher average thickness of the central ring area (ATC) and average volume of the central ring area (AVC) and lower choroidal vascularity index (CVI) compared to controls (β =  + 0.18, p = 0.0007, β =  + 0.18, p = 0.0008, respectively) and to dry AMD (β =  + 0.17, p = 0.00003 for both ATC and AVC and β =  − 0.30 p < 0.0001 for CVI). ATC, AVC and average volume (AV) were lower in AMD patients with hypertension and ischaemic heart disease (IHD). The duration of hypertension was inversely correlated with ATC, AVC and AV (Rs =  − 0.13, p < 0.05; Rs =  − 0.12; p < 0.05, Rs =  − 0.12; p < 0.05, respectively) while IHD duration negatively correlated with AV (Rs =  − 0.15, p < 0.05). No such associations were observed in the control group. Our findings show that the choroidal vascular system in eyes with AMD is much more susceptible to damage in the presence than in the absence of systemic vascular disease.
Self-assembling Hydrogels Based on Natural Building Blocks
Authors: Martin Charlotte , Ballet Steven
Published: July 2021

Hydrogels have been widely studied in the past two decades because of their high biocompatibility and versatility in many applications such as biomedicine and tissue engineering. In this chapter, we provide an overview of self-assembling hydrogels based on biomolecules including amino acids, peptides, proteins, saccharides, nucleobases and DNA. A focus is placed on the self-assembly process of ‘simple’ molecular entities via powerful and versatile noncovalent interactions, with specific attention for the design of supramolecular hydrogels.
Application of Natural Hydrogels for Cell Therapy: Focus on Osteoarthritis
Authors: Kim Changsu , Park Sang-Hyug
Published: July 2021

Regenerative medicine offers the potential to replace or repair different types of cells within damaged or defective tissues. Tissue engineering and cell therapy are promising approaches in regenerative medicine for the aging population. Particularly, treatments using therapeutic biomaterials are attractive methods for osteoarthritis (OA), which is the most common arthropathy. It is characterized by the gradual loss of articular cartilage that covers the ends of bones. Articular cartilage acts as a cushion against joint impact and enables flexible joint motion, but it has a very limited capacity for self-regeneration. Regenerative medicine technologies show promising results in cartilage regeneration using the transplantation of natural hydrogels containing various types of cells. Despite some clinical success in simple cartilage regeneration, many challenges remain in developing technologies to prevent OA progression and cartilage degradation. Injectable hydrogels have been of interest in minimal invasive treatment for OA as a cell delivery vehicle or as an inflammation modulator. Recently, the use of natural hydrogels has expanded into the areas of pain relief and reducing inflammation in OA patients. These scientific efforts have led to an effective, injectable hydrogel system to control inflammation and immunomodulation related to cartilage degradation. In this chapter, state-of-the-art tissue engineering technologies and the application of injectable natural hydrogels for OA treatment have been reviewed.
Status for Commercialization of FDA-approved Hydrogels and Their Intellectual Properties
Authors: Bhattacharyya Amitava , Janarthanan Gopinathan , Kang Julie , Noh Insup
Published: July 2021

Commercialization of U.S. Food and Drug Administration (FDA)-approved hydrogels and their intellectual properties (IP) have been extensively discussed by studying its various applications in biomedical and pharmaceutical fields. For drug delivery and physical barrier protection of wounds, the use of hydrogels in diverse forms, including injectable hydrogels, is practiced by physicians and pharmacists since long. In the last few decades, its applications encompass contact lenses, tissue engineering and 3D bioprinting, injectable hydrogels, cancer therapy, stent, etc. beyond the traditional medical devices and drug delivery. The U.S. FDA approved several hydrogel-based products while several such products are in the clinical trial stages. In this chapter, we try to highlight the approval status of various hydrogels and their specific applications in different biomedical areas, recent intellectual properties, the present market scenario of the hydrogels and the research trends on these topics.
Tetracycline antibiotics and NH4+ detection by Zn–organic framework fluorescent probe
Authors: Chen Jing , Xu Fanghong , Zhang Qian , Li Shuying , Lu Xiaoquan
Published: July 2021

Synthesis of Zn-MOF and OTC@Zn-MOF and the mechanism for detecting OTC and NH4+.
Boosting the peroxidase-like activity of gold nanoclusters for the colorimetric detection of oxytetracycline in rat serum
Authors: Zhang Xinya , Qiao Juan , Liu Wei , Qi Li
Published: July 2021

LTN@AuNCs display peroxidase-like activity in a TMB-H2O2 system. Their catalytic activity was enhanced by oxytetracycline. Using the mechanism, a protocol for highly selective and sensitive monitoring of rat serum drug was constructed.
Biocompatible nanomicelles for sensitive detection and photodynamic therapy of early-stage cancer
Authors: Zhou Hailin , Qi Zhongyuan , Pei Pei , Shen Wenhao , Zhang Yanxiang , Yang Kai , Sun Liang , Liu Teng
Published: July 2021

Biocompatible F127–PPa nanomicelles for sensitive detection and photodynamic therapy of early-stage cancer are developed.
Ultra-thin films of amphiphilic lanthanide complexes: multi-colour emission from molecular monolayers
Authors: O’Neil Alex T. , Harrison John A. , Kitchen Jonathan A.
Published: July 2021

Mixed deposition of amphiphilic Ln3+ complexes gives multi-emissive ultra-thin films.
Oxymetalation or oxidative cyclization? mechanism of Pd-catalyzed annulation of enynones
Authors: Ni Hao , He Xiaoqian , Zhong Kangbao , Chen Haohua , Lai Wei , Zhao Zhuang , Zeng Zhen , Bai Ruopeng , Lan Yu
Published: July 2021

Enynones are powerful synthons for constructing furan derivatives in the presence of transition metal catalysts.
Formation of BiOX (X = Cl and Br) in a mesoporous silica by the infiltration of Bi salts and the subsequent reaction with HX vapor
Authors: Paengjun Navarut (KAN) , Ogawa Makoto
Published: July 2021

The formation of BiOX (X = Br and Cl) nanoparticles in a mesoporous silica (SBA-15) was found by the reaction of the infiltrated bismuth oxo species with HX vapor at room temperature.
Electrochemical trifluoromethylation/cyclization for the synthesis of isoquinoline-1,3-diones and oxindoles
Authors: Guo Yuanqiang , Wang Ruiguo , Song Hongjian , Liu Yuxiu , Wang Qingmin
Published: July 2021

Herein, we describe a protocol for electrochemical cathode reduction to generate trifluoromethyl radicals.
Slight ligand modifications within multitopic linear hydroxamates promotes connectivity differences in Cu(ii) 1-D coordination polymers
Authors: Fugu Mohammed B. , Coley Joe , Dickinson Isabella F. , Orton James B. , Klooster Wim , Gleeson M. Paul , Jones Leigh F.
Published: July 2021

Two novel hydroxamic acids have been used in constructing two 1-D coordination polymers. Slight structural differences promote connectivity changes upon Cu(ii) metalation as rationalised using DFT calculations and Hirschfeld surface analysis.
Experimental and theoretical investigation of conformational states and noncovalent interactions in crystalline sulfonamides with a methoxyphenyl moiety
Authors: Kowalik Mateusz , Brzeski Jakub , Gawrońska Małgorzata , Kazimierczuk Katarzyna , Makowski Mariusz
Published: July 2021

The conformational and noncovalent interaction properties of sulfonamides with a methoxyphenyl moiety were examined by both experimental and theoretical methods.
Ultrafast decay dynamics of electronically excited 2-ethylpyrrole
Authors: Yuan Wenpeng , Yang Dongyuan , Feng Baihui , Min Yanjun , Chen Zhichao , Yu Shengrui , Wu Guorong , Yang Xueming
Published: July 2021

The ultrafast excited-state dynamics of 2-ethylpyrrole is studied in detail using the time-resolved photoelectron imaging method.
Effects of doping on photocatalytic water splitting activities of PtS2/SnS2 van der Waals heterostructures
Authors: Zhu Liang , Ding Yu-Feng , Yang Wei-Jun , Yin Shuang-Feng , Cai Meng-Qiu
Published: July 2021

Photocatalytic water splitting is a promising technology to solve serious energy and environmental problems.
Surface activation by electron scavenger metal nanorod adsorption on TiH2, TiC, TiN, and Ti2O3
Authors: Hinuma Yoyo , Mine Shinya , Toyao Takashi , Maeno Zen , Shimizu Ken-ichi
Published: July 2021

Supports with low work function have the potential to be activated by metal nanoparticle adsorption via the electron scavenger effect.
Aggregation-induced emission leading to two distinct emissive species in the solid-state structure of high-dipole organic chromophores
Authors: Witte Felix , Rietsch Philipp , Nirmalananthan-Budau Nithiya , Weigert Florian , Götze Jan P. , Resch-Genger Ute , Eigler Siegfried , Paulus Beate
Published: July 2021

Fluorescence lifetime measurements reveal two emissive species in the solid-state structure of high-dipole chromophores unravelled by high-level quantum-chemical approaches to originate from both monomers and H-type dimers.
Smart textiles for personalized thermoregulation
Authors: Fang Yunsheng , Chen Guorui , Bick Michael , Chen Jun
Published: July 2021

This article provides a fundamental understanding of the physiology of body thermoregulation and the advances in thermoregulatory textile technologies, and a perspective on future textiles for personalized thermoregulation.
Electrochemically induced metal- vs. ligand-based redox changes in mackinawite: identification of a Fe3+- and polysulfide-containing intermediate
Authors: Sanden Sebastian A. , Szilagyi Robert K. , Li Yamei , Kitadai Norio , Webb Samuel M. , Yano Takaaki , Nakamura Ryuhei , Hara Masahiko , McGlynn Shawn E.
Published: July 2021

Detection of Fe3+ and polysulfides during FeS oxidation revealing both metal, and ligand oxidation paths en route to the formation of greigite and pyrite.
A hybrid zeolitic imidazolate framework-derived ZnO/ZnMoO4heterostructure for electrochemical hydrogen production
Authors: Li Yang , Chen Shumei , Wu Xin , Zhang Huabin , Zhang Jian
Published: July 2021

A porous ZnO/ZnMoO4heterostructure is prepared by a hybrid zeolitic imidazolate framework-derived oxidation method for alkaline water electrolysis.
Synthesis of a task-specific imidazolium-based porous triazine polymer decorated with ultrafine Pd nanoparticles toward alcohol oxidation
Authors: Mao Yannan , Shi Yongqing , Su Yatao , Shen Qi , Zhang Yuangong , Wang Xianling , Wen Xin
Published: July 2021

Ultrafine Pd NPs supported on a task-specific imidazolium-linked porous triazine polymer were utilized as an effective catalyst for the oxidation of alcohols without any additive.
A large-scale study of ionic liquids employed in chemistry and energy research to reveal cytotoxicity mechanisms and to develop a safe design guide
Authors: Dzhemileva Lilya U. , D'yakonov Vladimir A. , Seitkalieva Marina M. , Kulikovskaya Natalia S. , Egorova Ksenia S. , Ananikov Valentine P.
Published: July 2021

Detailed study on the mechanisms of the cytotoxic action of various classes of ionic liquids including the first illustrative guide for designing ILs with targeted biological activity.
Superamphiphilic carbon from sawdust activated by oxygen/argon mixtures promoting the oxidation of benzyl alcohol in Pickering emulsion
Authors: Fan Honglei , Chen Bingfeng , Chen Chunjun , Zhang Zhaofu , Song Jinliang , Yang Guanying , Han Buxing
Published: July 2021

Superamphiphilic carbon from sawdust activated by oxygen/argon mixtures enhanced the efficiency of selective oxidation of benzyl alcohol by enriching the reactants around catalysts and inducing the formation of Pickering emulsions.
Schiff-base molecules and COFs as metal-free catalysts or silver supports for carboxylation of alkynes with CO2
Authors: Zhang Lin , Bu Ran , Liu Xiao-Yan , Mu Peng-Fei , Gao En-Qing
Published: July 2021

Triformylphloroglucinol-derived imine molecules and COFs act as transition-metal-free catalysts for the title reaction, and COFs are also composited with Ag nanoparticles to afford higher activity.
Antibiotic susceptibility test under a linear concentration gradient using travelling surface acoustic waves
Authors: Im Yongtaek , Kim Seunggyu , Park Jinsoo , Sung Hyung Jin , Jeon Jessie S.
Published: July 2021

TSAWs quickly form concentration gradients and make the AST easy to perform.
The role of liquid biopsies in prostate cancer management
Authors: Kim Chi-Ju , Dong Liang , Amend Sarah R. , Cho Yoon-Kyoung , Pienta Kenneth J.
Published: July 2021

This review describes recent advances in isolation and detection technology for circulating biomarkers. The clinical studies based on liquid biopsy results are summarized to provide a perspective on the role of such results in prostate cancer management.
Green-synthesized copper oxide nanostructures for potential multifaceted biomedical applications
Authors: Ruddaraju Lakshmi Kalyani , Veerla Sarath Chandra , Kolapalli Venkata Ramana Murthy , Pallela Panduranga Naga Vijay Kumar , Padavala Veerabhadra Swamy , Pammi S. V. N.
Published: July 2021

The novelty of the present work is the in-vitro and in vivo nano-antibitoic combinational therapy along with in vitro anti-cancer and biocompatibility activities of green synthesized CuO NLs.
Silver-catalysed C–H bond activation: a recent review
Authors: Radhika Sankaran , Abdulla C. M. Afsina , Aneeja Thaipparambil , Anilkumar Gopinathan
Published: July 2021

Transition metal catalysed C–H activations are efficient, simple, mild, cost-effective and stereoselective, and many of them are environmentally sustainable transformations.
Introduction of a luminescent sensor for tracking trace levels of hydrazine in insect pollinated cropland flowers
Authors: Saha Shrabani , Das Sujoy , Sarkar Olivia , Chattopadhyay Ansuman , Rissanen Kari , Sahoo Prithidipa
Published: July 2021

Introduction of an efficient chemodosimeter (NCD) to estimate the mutagenic hydrazine within several affected cropland flowers promptly showing ‘turn-on’ fluorescence.
Structural and electronic properties of a novel two-dimensional Janus Pd4S3Se3 monolayer controllable by electric field and strain engineering
Authors: Pham D. K. , Nguyen Son-Tung , Nguyen C. Q.
Published: July 2021

In this work, we investigate the structural and electronic properties of a newly-discovered two-dimensional Janus Pd4S3Se3 monolayer, as well as its controllable structural and electronic properties under an electric field and strain engineering using first-principles calculations.
Ruthenium-catalyzed N-alkylation of amino-1,3,5-triazines using alcohols
Authors: Zhao Junna , Zhong Pengzhen , Xie Zhongpao , Zhou Wei , Zhang Chen , Cui Dong-Mei
Published: July 2021

An efficient ruthenium-catalyzed N-alkylation of amino-1,3,5-triazines with alcohols was achieved via BH/HA strategy.
Achieving complementary resistive switching and multi-bit storage goals by modulating the dual-ion reaction through supercritical fluid-assisted ammoniation
Authors: Li Lei , Dai Tianjiao , Liu Kai , Chang Kuan-Chang , Zhang Rui , Lin Xinnan , Liu Heng-Jui , Lai Ying-Chih , Kuo Tzu-Peng
Published: July 2021

Achieving reliable self-compliant complementary resistive switching (CRS) in a single device through supercritical fluid-assisted ammoniation (SFA) technology.
Correction: Characterization of a carboxyl methyltransferase in Fusarium graminearum provides insights into the biosynthesis of fusarin A
Authors: Yang Qian , Wang Wanqiu , Lin Yueting , Lin Yuqi , Tang Zhijun , Wang Jing , Tao Jiang , Tang Weihua , Liu Wen
Published: July 2021

Correction for ‘Characterization of a carboxyl methyltransferase in Fusarium graminearum provides insights into the biosynthesis of fusarin A’ by Qian Yang et al., Org. Biomol. Chem., 2021, DOI: 10.1039/d1ob01010g.
A design strategy for D–A conjugated polymers for NIR-II fluorescence imaging
Authors: Su Yingbin , Miao Yawei , Zhu Yaowei , Zou Wentao , Yu Bing , Shen Youqing , Cong Hailin
Published: July 2021

The development of bioimaging technology in recent years has shown that second near-infrared (NIR-II) fluorescence imaging (FI) is gradually replacing the traditional visible light and first near-infrared (NIR-I) FI.
Alkali-regulated Fe6 and Fe18 molecular clusters and their structural transformation
Authors: Li Xiao-Yu , Zou Ying , Han Song-De , Wang Guo-Ming
Published: July 2021

A cyclic Fe6 like a “six-vane windmill” and a bricky Fe18 clusters as a “Chinese knot” were obtained. Moreover, the alkali-induced conversion from Fe6 to Fe18 has been achieved, realizing the nuclearity enlargement and structural regulation.
Metal-free sulfonylative annulations of alkyl diiodides with sulfur dioxide: synthesis of cyclic aliphatic sulfones
Authors: Jia Xiuwen , Huang Chunxi , Zhang Xuemei , Lian Zhong
Published: July 2021

A straightforward protocol for cyclic aliphatic sulfones is effectively established via sulfonylative annulations of alkyl diiodides and gaseous sulfur dioxide. Five- to nine-membered cyclic aliphatic sulfones were afforded in this manner.
Machine learning of solvent effects on molecular spectra and reactions
Authors: Gastegger Michael , Schütt Kristof T. , Müller Klaus-Robert
Published: July 2021

A machine learning approach for modeling the influence of external environments and fields on molecules has been developed, which allows the prediction of various types of molecular spectra in vacuum and under implicit and explicit solvation.
Mechanistic roles for altered O-GlcNAcylation in neurodegenerative disorders
Authors: Balana Aaron T. , Pratt Matthew R.
Published: July 2021

Neurodegenerative diseases such as Alzheimer's and Parkinson's remain highly prevalent and incurable disorders. A major challenge in fully understanding and combating the progression of these diseases is the complexity of the network of processes that lead to progressive neuronal dysfunction and death. An ideal therapeutic avenue is conceivably one that could address many if not all of these multiple misregulated mechanisms. Over the years, chemical intervention for the up-regulation of the endogenous posttranslational modification (PTM) O-GlcNAc has been proposed as a potential strategy to slow down the progression of neurodegeneration. Through the development and application of tools that allow dissection of the mechanistic roles of this PTM, there is now a growing body of evidence that O-GlcNAc influences a variety of important neurodegeneration-pertinent mechanisms, with an overall protective effect. As a PTM that is appended onto numerous proteins that participate in protein quality control and homeostasis, metabolism, bioenergetics, neuronal communication, inflammation, and programmed death, O-GlcNAc has demonstrated beneficence in animal models of neurodegenerative diseases, and its up-regulation is now being pursued in multiple clinical studies.
Importance of tyrosine phosphorylation for transmembrane signaling in plants
Authors: Mühlenbeck Henning , Bender Kyle W. , Zipfel Cyril
Published: July 2021

Reversible protein phosphorylation is a widespread post-translational modification fundamental for signaling across all domains of life. Tyrosine (Tyr) phosphorylation has recently emerged as being important for plant receptor kinase (RK)-mediated signaling, particularly during plant immunity. How Tyr phosphorylation regulates RK function is however largely unknown. Notably, the expansion of protein Tyr phosphatase and SH2 domain-containing protein families, which are the core of regulatory phospho-Tyr (pTyr) networks in choanozoans, did not occur in plants. Here, we summarize the current understanding of plant RK Tyr phosphorylation focusing on the critical role of a pTyr site (‘VIa-Tyr’) conserved in several plant RKs. Furthermore, we discuss the possibility of metazoan-like pTyr signaling modules in plants based on atypical components with convergent biochemical functions.
Histone mimics: more tales to read
Authors: Yu Yucong , Wen Hong , Shi Xiaobing
Published: July 2021

Post-translational modifications (PTMs) on histone proteins are known as epigenetic marks that demarcate the status of chromatin. These modifications are ‘read' by specific reader proteins, which in turn recruit additional factors to modulate chromatin accessibility and the activity of the underlying DNA. Accumulating evidence suggests that these modifications are not restricted solely to histones, many non-histone proteins may function in a similar way through mimicking the histones. In this commentary, we briefly discuss a systematic study of the discovery of histone H3 N-terminal mimicry proteins (H3TMs), and their implications in chromatin regulation and drug discoveries.
Plant long non-coding RNAs in the regulation of transcription
Authors: Chekanova Julia A.
Published: July 2021

Eukaryotic genomes are pervasively transcribed, producing large numbers of non-coding RNAs (ncRNAs), including tens of thousands of long ncRNAs (lncRNAs), defined as ncRNAs longer than 200 nucleotides. Recent studies have revealed the important roles lncRNAs play in the regulation of gene expression at various levels in all eukaryotes; moreover, emerging research in plants has identified roles for lncRNAs in key processes such as flowering time control, root organogenesis, reproduction, and adaptation to environmental changes. LncRNAs participate in regulating most steps of gene expression, including reshaping nuclear organization and chromatin structure; governing multiple steps of transcription, splicing, mRNA stability, and translation; and affecting post-translational protein modifications. In this review, I present the latest progress on the lncRNA-mediated regulatory mechanisms modulating transcription in Arabidopsis thaliana, focusing on their functions in regulation of gene expression via chromatin structure and interactions with the transcriptional machinery.
Latent label mining for group activity recognition in basketball videos
Authors: Wu Lifang , Li Zeyu , Xiang Ye , Jian Meng , Shen Jialie
Published: July 2021

Motion information has been widely exploited for group activity recognition in sports video. However, in order to model and extract the various motion information between the adjacent frames, existing algorithms only use the coarse video‐level labels as supervision cues. This may lead to the ambiguity of extracted features and the omission of changing rules of motion patterns that are also important sports video recognition. In this paper, a latent label mining strategy for group activity recognition in basketball videos is proposed. The authors' novel strategy allows them to obtain the latent labels set for marking different frames in an unsupervised way, and build the frame‐level and video‐level representations with two separate levels of supervision signal. Firstly, the latent labels of motion patterns are digged using the unsupervised hierarchical clustering technique. The generated latent labels are then taken as the frame‐level supervision signal to train a deep CNN for the frame‐level features extraction. Lastly, the frame‐level features are fed into an LSTM network to build the spatio‐temporal representation for group activity recognition. Experimental results on the public NCAA dataset demonstrate that the proposed algorithm achieves state‐of‐the‐art performance.
AFF‐UNIT: Adaptive feature fusion for unsupervised image‐to‐image translation
Authors: Li Yuqiang , Meng Haochen , Lin Hong , Liu Chun
Published: July 2021

The task of image‐to‐image translation is to generate images closer to the target domain style while preserving the significant features of the original image. This paper contends an adaptive feature fusion method for unsupervised image translation. The proposed architecture, termed as AFF‐UNIT, is based on a compact network structure to further improve the quality of generated images. First of all, a feature extraction module based on an adaptive feature fusion method is proposed, which combines low‐level fine‐grained information and high‐level semantic information to obtain feature maps with richer information. At the same time, a feature‐similarity loss is proposed to guide the feature extraction module to extract features that are more conducive to improving the translation result. In addition, AFF‐UNIT reuses the feature extraction module in the generator and discriminator to simplify the framework. Extensive experiments on five popular benchmarks demonstrate the superior performance of AFF‐UNIT over state‐of‐the‐art methods in terms of FID, KID, IS, and also human preference. Comprehensive ablation studies are also carried out to isolate the validity of each proposed component.
Review of HVDC systems for enhancing resilience after extreme natural events
Authors: Luo Chuhang , Liang Liang , Bai Xiaoyang
Published: July 2021

Compared with AC systems, HVDC systems are more flexible and potentially contribute to enhancing system resilience. Currently, three types of HVDC technologies, LCC‐HVDC (Line‐commutated Current‐sourced Converters, LCC), VSC‐HVDC (Voltage Sourced Converter, VSC), and MMC‐HVDC (Modular‐Multilevel‐Converter, MMC), are applied in practical projects. All types of HVDC systems can be applied to stabilize the system frequency of AC power systems and facilitate system recovery after extreme natural events. The operation characteristics, methods, and control strategies of different HVDC technologies for facilitating system operation are reviewed herein; it is indicated that HVDC technology is an effective solution for enhancing system resilience. Renewable resources, energy storage systems, and demand response devices can be coordinated well with HVDC systems. The frequency and voltage regulation ability of power systems and the black start ability can be enhanced by introducing HVDC systems into power systems. Several isolated AC power systems can be connected to HVDC systems. These AC systems can interact with other AC systems through HVDC systems by conforming to their operational characteristics and constraints. The resilience of these AC systems can be enhanced by these interactions. Additionally, related operation methods and control strategies will also be reviewed.
RadioAstron reveals a spine-sheath jet structure in 3C 273
Authors: Bruni G. , Gómez J. L. , Vega-García L. , Lobanov A. P. , Fuentes A. , Savolainen T. , Kovalev Y. Y. , Perucho M. , Martí J.-M. , Anderson J. M. , Edwards P. G. , Gurvits L. I. , Lisakov M. M. , Pushkarev A. B. , Sokolovsky K. V. , Zensus J. A.
Published: July 2021

We present Space-VLBI RadioAstron observations at 1.6 GHz and 4.8 GHz of the flat spectrum radio quasar 3C 273, with detections on baselines up to 4.5 and 3.3 Earth Diameters, respectively. Achieving the best angular resolution at 1.6 GHz to date, we have imaged limb-brightening in the jet, not previously detected in this source. In contrast, at 4.8 GHz, we detected emission from a central stream of plasma, with a spatial distribution complementary to the limb-brightened emission, indicating an origin in the spine of the jet. While a stratification across the jet width in the flow density, internal energy, magnetic field, or bulk flow velocity are usually invoked to explain the limb-brightening, the different jet structure detected at the two frequencies probably requires a stratification in the emitting electron energy distribution. Future dedicated numerical simulations will allow the determination of which combination of physical parameters are needed to reproduce the spine-sheath structure observed by Space-VLBI with RadioAstron in 3C 273.
MONOS: Multiplicity Of Northern O-type Spectroscopic systems
Authors: Trigueros Páez E. , Barbá R. H. , Negueruela I. , Maíz Apellániz J. , Simón-Díaz S. , Holgado G.
Published: July 2021

Context. Massive stars are a key element for understanding the chemical and dynamical evolution of galaxies. Stellar evolution is conditioned by many factors: Rotation, mass loss, and interaction with other objects are the most important ones for massive stars. During the first evolutionary stages of stars with initial masses (i.e., MZAMS) in the MZAMS ∼ 18–70  M⊙ range, they are of spectral type O. Given that stars in this mass range spend roughly 90% of their lifetime as O-type stars, establishing the multiplicity frequency and binary properties of O-type stars is crucial for many fields of modern astrophysics.

Aims. The aim of the MONOS project is to collect information to study northern Galactic O-type spectroscopic binaries. In this second paper, we tackle the study of the 35 single-line spectroscopic binary (SB1) systems identified in the previous paper of the series, analyze our data, and review the literature on the orbits of the systems.

Methods. We have measured ∼4500 radial velocities for a selection of diagnostic lines for the ∼700 spectra of the studied systems in our database, for which we have used two different methods: a Gaussian fit for several lines per object and cross-correlation with synthetic spectra computed with the FASTWIND stellar atmospheric code. We have also explored the photometric data delivered by the TESS mission to analyze the light curve (LC) of the systems, extracting 31 of them. We have explored the possible periods with the Lomb-Scargle method and, whenever possible, calculated the orbital solutions using the SBOP and GBART codes. For those systems in which an improved solution was possible, we merged our radial velocities with those in the literature and calculated a combined solution.

Results. As a result of this work, of the 35 SB1 systems identified in our first paper we have confirmed 21 systems as SB1 with good orbits, discarded the binary nature of six stars (9 Sge, HD 192 281, HDE 229 232 AB, 68 Cyg, HD 108, and α Cam), and left six stars as inconclusive due to a lack of data. The remaining two stars are 15 Mon Aa, which has been classified as SB2, and Cyg OB2-22 C, for which we find evidence that it is most likely a triple system where the O star is orbiting an eclipsing SB1. We have also recalculated 20 new orbital solutions, including the first spectroscopic orbital solution for V747 Cep. For Cyg OB2-22 C, we have obtained new ephemerides but no new orbit.
Physical characterization of recently discovered globular clusters in the Sagittarius dwarf spheroidal galaxy
Authors: Garro E. R. , Minniti D. , Gómez M. , Alonso-García J.
Published: July 2021

Context.Globular clusters (GCs) are important tools for rebuilding the accretion history of a galaxy. In particular, newly discovered GCs in the Sagittarius (Sgr) dwarf galaxy can be used as probes of the accretion event onto the Milky Way (MW).

Aims.Our main aim is to characterize the GC system of the Sgr dwarf galaxy by measuring its main physical parameters.

Methods.We built the optical and near-infrared color-magnitude diagrams for 21 new Sgr GCs using the VISTA Variables in the Via Lactea Extended Survey near-infrared database combined with theGaiaEarly Data Release 3 optical database. We derived metallicities and ages for all targets using the isochrone-fitting method with PARSEC isochrones. We also used the relation between red giant branch slope and metallicity as an independent method to confirm our metallicity estimates. In addition, the total luminosities were calculated in the near-infrared and in the optical. We then constructed the metallicity distribution (MD), the globular cluster luminosity function (GCLF), and the age-metallicity relation for the Sgr GC system.

Results.We find that there are 17 metal-rich GCs with −0.9 < [Fe/H]<  − 0.3, plus 4 metal-poor GCs with −2.0 < [Fe/H]<  − 1.1 in the new Sgr GC sample. The metallicity estimates using isochrones and red giant branch slopes agree well. Even though our age estimates are rough, we find that the metal-poor GCs are consistent with an old population with an average age of ∼13 Gyr, while the metal-rich GCs show a wider age range, between 6 − 8 Gyr and 10 − 13 Gyr. Additionally, we compare the MD and the GCLF for the Sgr GC system with those of the MW, M31, and Large Magellanic Cloud galaxies.

Conclusions.We conclude that the majority of the metal-rich GCs are located within the main body of the Sgr galaxy. We confirm that the GCLF is not a universal distribution because the Sgr GCLF peaks at fainter luminosities (MV ≈ −5.5 mag) than the GCLFs of the MW, M31, and Large Magellanic Cloud. Moreover, the MD shows a double-peaked distribution, and we note that the metal-rich population looks like the MW bulge GCs. We compared our results with the literature and conclude that the Sgr progenitor could have been a reasonably large galaxy able to retain the supernovae ejecta, thus enriching its interstellar medium.
Accepting networks of evolutionary processors with resources restricted and structure limited filters
Authors: Dassow Jürgen , Truthe Bianca
Published: July 2021

In this paper, we continue the research on accepting networks of evolutionary processors where the filters belong to several special families of regular languages. We consider families of codes or ideals and subregular families which are defined by restricting the resources needed for generating or accepting them (the number of states of the minimal deterministic finite automaton accepting a language of the family as well as the number of non-terminal symbols or the number of production rules of a right-linear grammar generating such a language). We insert the newly defined language families into the hierachy of language families obtained by using as filters languages of other subregular families (such as ordered, non-counting, power-separating, circular, suffix-closed regular, union-free, definite, combinational, finite, monoidal, nilpotent, or commutative languages).
Digging input-driven pushdown automata
Authors: Kutrib Martin , Malcher Andreas
Published: July 2021

Input-driven pushdown automata (IDPDA) are pushdown automata where the next action on the pushdown store (push, pop, nothing) is solely governed by the input symbol. Nowadays such devices are usually defined such that popping from the empty pushdown does not block the computation but continues it with empty pushdown. Here, we consider IDPDAs that have a more balanced behavior concerning pushing and popping. Digging input-driven pushdown automata (DIDPDA) are basically IDPDAs that, when forced to pop from the empty pushdown, dig a hole of the shape of the popped symbol in the bottom of the pushdown. Popping further symbols from a pushdown having a hole at the bottom deepens the current hole furthermore. The hole can only be filled up by pushing symbols previously popped. We study the impact of the new behavior of DIDPDAs on their power and compare their capacities with the capacities of ordinary IDPDAs and tinput-driven pushdown automata which are basically IDPDAs whose input may be preprocessed by length-preserving finite state transducers. It turns out that the capabilities are incomparable. We address the determinization of DIDPDAs and their descriptional complexity, closure properties, and decidability questions.
On deterministic 1-limited 5′ → 3′ sensing Watson–Crick finite-state transducers
Authors: Nagy Benedek , Kovács Zita
Published: July 2021

Finite automata and finite state transducers belong to the bases of (theoretical) computer science with many applications. On the other hand, DNA computing and related bio-inspired paradigms are relatively new fields of computing. Watson–Crick automata are in the intersection of the above fields. These finite automata have two reading heads as they read the upper and lower strands of the input DNA molecule, respectively. In 5′ → 3′ Watson–Crick automata the two reading heads move in the same biochemical direction, that is, from the 5′ end of the strand to the direction of the 3′ end. However, in the double-stranded DNA, the DNA strands are directed in opposite way to each other, therefore 5′ → 3′ Watson–Crick automata read the input from the two extremes. In sensing 5′ → 3′ automata the automata sense if the two heads are at the same position, moreover, the computing process is finished at that time. Based on this class of automata, we define WK transducers such that, at each transition, exactly one input letter is being processed, and exactly one output letter is written on a normal output tape. Some special cases are defined and analyzed,e.g., when only one of the reading heads is being used and when the transducer has only one state. We also show that the minimal transducer is uniquely defined if the transducer is deterministic and it has marked output,i.e., the output letter written in a step identifies the reading head that is used in that transition. We have also used the functions ‘processing order’ and ‘reading heads’ to analyze these transducers.
Ecological status estimation of eight creeks in the Lake Sapanca Basin (Sakarya, Turkey) using diatom indices
Authors: Ongun Sevindik Tuğba , Alemdar Esra , Uzun Ali , Coşkun Tolga , Tunca Hatice
Published: July 2021

It is important to determine the water quality of the creeks in the Lake Sapanca basin since it is used for drinking water supply. For this purpose, environmental parameters and diatom assemblages as biological quality components were investigated to determine the ecological status of eight creeks with monthly intervals between March 2015 and February 2016. During the studied period, 19 taxa increased their relative abundance higher than 30% in at least one sample and showed a different seasonal pattern. Main nutrients [(nitrate-nitrogen, orthophosphate, total phosphorus (TP)] and some other parameters (specific conductance, temperature, pH, and dissolved oxygen) had strong impacts on the distribution of diatom assemblages. The ecological status of the creeks was characterized by using four different diatom indices, however, only Trophic Index Turkey (TIT) represented significant positive correlations with log (TP) gradient and separated the creeks as good and moderate ecological status. According to TIT, the 4th and 6th stations had a good ecological condition and were characterized by pollution-sensitive species such as Cymbella affinis, Reimeria sinuata, and Nitzschia dissipata. On the other hand, TIT resulted in the other stations having moderate ecological conditions, which had high nutrient levels and EC. Moreover, the occurrence of pollution-tolerant taxa such as Gomphonema angustatum, Ulnaria ulna, and Achnanthidium affine endorsed the moderate ecological conditions in these creeks. Based on the results, the TIT as a biological metric could be a useful tool for the assessment of running waters in the Sakarya river basin.
Endoscopic neo-anastomosis by Rendez-vous technique for the treatment of complete occlusion of bilioenteric anastomoses and distal bile ducts (case series)
Authors: Steinbrück Ingo , Otto Helge , Ullrich Sebastian , Ruether Christoph , Fischbach Roman , Pohl Jürgen , Hagenmüller Friedrich
Published: July 2021

Background and aims The complete occlusion of bilioenteric anastomoses is a rare and challenging clinical condition. Repeated surgery is burdened with technical difficulties and significant morbidity. We report the first series of completely occluded bilioenteric anastomoses resp. distal bile duct successfully treated by simultaneous percutaneous and retrograde endoscopic interventions.

Patients and methods This case series includes 4 patients with obstructive jaundice and/or recurring cholangitis and pain due to complete fibrotic occlusion of a hepaticojejunostomy (3 patients) and the distal bile duct (1 patient). After performing PTCD and stepwise dilation of the biliocutaneous tract, we tried to approach the occluded anastomosis from 2 sides by simultaneous percutaneous cholangioscopy and peroral device-assisted enteroscopy/duodenoscopy. By cutting through the separating tissue layer with a needle knife under endoscopic and fluoroscopic control using diaphanoscopy, a new anastomosis should be established followed by dilation of the neoanastomosis with subsequent percutaneous transhepatic drainage for a minimum of 1 year to prevent re-occlusion.

Results The Rendez-vous maneuver was successful in 3/4 cases. In one case, the retrograde access to the anastomosis failed, so the neoanastomosis was cut under cholangioscopic and fluoroscopic guidance only. The neoanastomosis could be established successfully in all 4 cases. Jaundice, cholangitis, and pain disappeared. Minor periinterventional adverse events were cholangitis (n = 1) and pneumonia (n = 1) due to aspiration, which could be managed conservatively. No serious adverse events were observed, and no re-occlusion of any neoanastomosis occurred during the follow-up before and after removal of the percutaneous drainage.

Conclusion Simultaneous percutaneous cholangioscopy and device-assisted enteroscopy/duodenoscopy with endoscopic creation of a neoanastomosis is a possible concept for the treatment of completely occluded bilioenteric anastomoses and distal bile ducts. This case series confirms the feasibility, safety, and long-term effectiveness of this treatment.
Techniques for Imaging Vascular Supply of Peripheral Nerves
Authors: Giron Alec , Cox Cameron , MacKay Brendan
Published: July 2021

Few studies have been developed to map the vascular structures feeding peripheral nerves, with the majority using cadaveric models and inadequate sample sizes. Preliminary evidence, while limited, indicates that the mapping of these vessels may allow or preclude certain procedures in nerve reconstruction due to the location of essential arterial inflow to the vasa nervorum. This review evaluates the evidence regarding historical, current, and emerging techniques for visualizing these vascular structures in vivo and considers their potential application in peripheral nerve vasculature.
Accuracy and Safety of Image-Guided Freehand Pin Placement in Canine Cadaveric Vertebrae
Authors: Samer Eva S. , Forterre Franck , Rathmann Justus M.K. , Stein Veronika M. , Precht Christina M. , Guevar Julien
Published: July 2021

Objective The aim of this study was to validate an imaging technique for evaluation of spinal surgery accuracy and to establish accuracy and safety of freehand technique in the thoracolumbar spine of large breed dogs.

Study Design After thoracolumbar spine computed tomography (CT), 26 drilling corridors were planned then drilled to receive 3.2 mm positive profile pins using a freehand technique. After pin removal, CT was repeated. All entry points, exit points and angles of the preoperative planned trajectories were compared with postoperative ones using an image registration and fusion technique by three observers. Corridor coordinates for entry and exit points were evaluated in three dimensions and angles were measured in one plane. Intraclass correlation coefficient (ICC) was used to establish the imaging technique reliability and descriptive statistics were used to report on the freehand technique accuracy. Safety was evaluated using a vertebral cortical breach grading scheme.

Results Intraclass correlation coefficient for the entry points, exit points and angle were 0.79, 0.96 and 0.92 respectively. Mean deviations for the entry points, exit points and angle were 3.1 mm, 6.3 mm and 7.6 degrees respectively. Maximum deviations were 6.3 mm, 11.0 mm and 16.4 degrees. Most deviations were lateral and caudal. All corridors were judged as safe.

Conclusion The imaging technique reliability was good to excellent to study spinal surgery accuracy. Implant deviations should be anticipated when planning stabilization surgery in large breed dogs using the freehand-guided technique.
Wurtzite ScAlN, InAlN, and GaAlN crystals, a comparison of structural, elastic, dielectric, and piezoelectric properties
Authors: Ambacher O. , Christian B. , Feil N. , Urban D. F. , Elsässer C. , Prescher M. , Kirste L.
Published: July 2021

We present detailed investigations of the structural, elastic, dielectric, and piezoelectric properties of scandium aluminum nitride (ScxAl1−xN) with the wurtzite crystal structure by means of first-principles calculations based on density functional theory in order to enable a detailed comparison to the corresponding physical properties of GaAlN and InAlN. The goal of our approach is to use atomistic simulations to extract the novel solid state characteristics of ScxAl1−xN crystals by the determination of complete sets of coefficients for the elastic, compliance, and piezoelectric tensor and to confirm the theoretical predictions by experimental measurements of selected tensor coefficients. The calculation of the tensor components is accompanied by a detailed analysis of the crystal structures, e.g., average bond length, bond angles, lattice parameters, and mass density in dependence on alloy composition of ScxAl1−xN. If an increasing number of Al atoms of up to x = 0.5 are replaced by Sc atoms, we observe a nonlinear change of the ratio of lattice parameter c(x)a(x) and average bond angles of about 10% and 5%, respectively, which give an indication of an increasing deviation of the crystal structure of ScxAl1−xN from an ideal hexagonal lattice. As a consequence of the deformed crystal structure and the iconicity of the Sc–N bond, we predict a change in value of the elastic coefficient C33ScAlN(x), the piezoelectric coefficient e33ScAlN(x), and the value of spontaneous polarization PSPScAlN(x) of up to 65%, 150%, and 230%, respectively. Based, on these simulation results, physical features of practical use are derived, like the average bulk, shear, and the Young modulus as well as the reciprocal Young's modulus and Poisson ratio. Furthermore, the spontaneous polarization of ScxAl1−xN is approximated, taking nonlinear effects into account as well as the piezoelectric polarization caused by uniaxial, biaxial, and hydrostatic stresses in dependency on alloy composition and strain. A detailed comparison of the structural and polarization related properties of GaAlN and InAlN allows us to point out the peculiarity of wurtzite ScAlN crystals within the group III-nitrides.
Experimental observation of the geodesic acoustic frequency limit for the NBI-driven Alfvén eigenmodes in TJ-II
Authors: Eliseev L. G. , Melnikov A. V. , Ascasibar E. , Cappa A. , Drabinskiy M. , Hidalgo C. , Khabanov P. O. , Kharchev N. K. , Kozachek A. S. , Liniers M. , Lysenko S. E. , Ochando M. , Pablos J. L. de , Pastor I. , Sharapov S. E. , Spong D. A. , Breizman B. N. , Varela J.
Published: July 2021

We study Alfvén eigenmodes (AEs) in the TJ-II heliac in hydrogen plasmas heated by hydrogen co-field neutral beam injector. Taking advantage of the unique TJ-II flexibility in a varying plasma current, we have observed strong variation of the AE frequency from fAE ∼ 30 to ∼220 kHz for selected modes. An advanced heavy-ion beam probe diagnostic determines the spatial location and internal amplitudes of the modes. The modes satisfy a local AE dispersion relation including the geodesic acoustic frequency that represents the lowest frequency of the mode. Linear MHD modeling with STELLGAP and FAR3D codes shows that the calculated temporal evolution of the mode frequency reproduces the observed maxima and minima at the same time intervals with a similar frequency range, and the radial profile peaks near the outer edge of the observed one.